Cranial Neuropathy

Cranial Neuropathy. Perineural tumor spread can lead to isolated or multiple CN palsies and is the macroscopic spread of tumor along the course of a nerve distant from the site of the primary tumor as detected on imaging. It should be distinguished from perineural invasion, which is local invasion detected on histopathologic diagnosis at the primary tumor site [66,124]. Perineural tumor spread on imaging is associated with a worse prognosis [195]. The trigeminal (CN V) and facial (CN VII) nerves are most commonly affected by perineural tumor spread, although any nerve traveling in the vicinity of a malignancy may become involved. A multitude of tumors can result in perineural tumor spread, with squamous cell carcinoma (cutaneous and mucosal), adenoid cystic carcinoma, melanoma, lymphoma, basal cell carcinoma, and mucoepidermoid carcinoma most commonly occurring in the head and neck. Clues to perineural tumor spread include effacement of perineural and juxtaforaminal fat; asymmetric nerve enlargement or enhancement; osseous foraminal enlargement or erosion; and imaging features of denervation injury [65,66,104,123,124,196]. CT Head There is no relevant literature to support the use of routine head CT in the initial evaluation of perineural spread of tumor. CT Maxillofacial There is no relevant literature to support the use of routine maxillofacial CT in the initial evaluation of perineural spread of tumor. Contrast-enhanced maxillofacial CT may be complementary to MRI and is useful for characterizing osseous changes of skull base and neural foramina; however, contrast-enhanced neck CT with thin- cut high-resolution bone algorithm windows through the skull base can provide similar information while Cranial Neuropathy simultaneously staging the neck [64,66]. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Temporal Bone There is no relevant literature to support the use of routine temporal bone CT in the initial evaluation of perineural spread of tumor.


Cranial Neuropathy

Cranial Neuropathy. Temporal bone CT with IV contrast may be complementary to MRI and is useful for characterizing osseous changes of the skull base and neural foramina and may be useful to characterize perineural fat planes; however, contrast-enhanced neck CT with thin-cut high-resolution bone algorithm windows through the skull base can provide similar information while simultaneously staging the neck [64,66]. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Neck MRI has better sensitivity for detection of perineural spread of tumor compared with CT and is the preferred study for initial assessment of perineural spread of tumor [65]. The trigeminal (CN V) and facial (CN VII) nerves are most commonly affected by perineural tumor spread and have branches extending into the face and neck. Neck CT may be complementary to MRI and is useful for characterizing osseous changes of the skull base and neural foramina and may be useful to characterize perineural fat planes while simultaneously staging the neck [64,66]. Contrast should be administered. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CTA Head and Neck There is no relevant literature to support the use of CTA head and neck in the initial evaluation of perineural spread of tumor. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is not routinely used in the initial evaluation of the perineural spread of tumor, although perineural tumor spread may be detected on metabolic imaging. FDG-PET/CT may be useful for staging and response assessment in patients with a known primary malignancy [195,197]. Contrast-enhanced PET/MR may detect perineural spread of a tumor and may be useful as an alternate to PET/CT in the evaluation of patients with head and neck cancers [164]. MRA Head and Neck There is no relevant literature to support the use of MRA in the initial evaluation of perineural spread of tumor.


Cranial Neuropathy

Cranial Neuropathy. Sensitivities for MRI detection of perineural spread of tumor range from 73% to 100% and vary according to the nerve evaluated and timing of imaging relative to tissue sampling [65,104,123-125]. MRI may underestimate microscopic perineural spread of a tumor [123-125]. Advanced imaging techniques such as tractography may be useful to detect perineural tumor spread but require further investigation [130]. Contrast-enhanced PET/MR may detect perineural spread of a tumor and may be useful as an alternate to PET/CT in the evaluation of patients with head and neck cancers [164]. Cranial Neuropathy Sensitivities for MRI detection of perineural spread of a tumor range from 73% to 100% and vary according to the nerve evaluated and timing of imaging relative to tissue sampling [65,104,123-125]. MRI may underestimate microscopic perineural spread of a tumor [123-125]. Advanced imaging techniques such as tractography may be useful to detect perineural tumor spread but require further investigation [130]. Contrast-enhanced PET/MR may detect perineural spread of a tumor and may be useful as an alternate to PET/CT in the evaluation of patients with head and neck cancers [164]. Cranial Neuropathy Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation. For additional information on the Appropriateness Criteria methodology and other supporting documents go to www. acr.org/ac. Appropriateness Category Names and Definitions Relative Radiation Level Information Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination.


Palpable Breast Masses

Palpable Breast Masses.  Imaging evaluation is necessary to adequately characterize a palpable breast mass. After thorough clinical breast examination, usually by the referring clinician or by a specialist breast clinician, the radiologist must be able to establish concordance between the clinically detected mass and the imaging features at that location [2]. The negative predictive value of mammography with ultrasound (US) in the context of a palpable mass ranges from 97.4% to 100% [7-10]. Nevertheless, negative imaging evaluation should not deter biopsy when a strongly suspicious finding is present on physical examination. OR aUniversity of Michigan, Ann Arbor, Michigan. bResearch Author, Duke University Medical Center, Durham, North Carolina. cPanel Chair, Alpert Medical School of Brown University, Providence, Rhode Island. dPanel Vice-Chair, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida. eWashington University School of Medicine, Saint Louis, Missouri. fPenn State Health Hershey Medical Center, Hershey, Pennsylvania. gUniversity of Utah, Salt Lake City, Utah. hKaiser Permanente, Atlanta, Georgia. iMemorial Sloan Kettering Cancer Center, New York, New York. jUniversity of Washington, Seattle, Washington; American College of Obstetricians and Gynecologists. kSt. Bernards Healthcare, Jonesboro, Arkansas. lDuke Signature Care, Durham, North Carolina; American College of Physicians. mUMass Memorial Medical Center/UMass Chan Medical School, Worcester, Massachusetts. nProMedica Breast Care, Toledo, Ohio. oFox Chase Cancer Center, Philadelphia, Pennsylvania; American College of Surgeons. pHoag Family Cancer Institute, Newport Beach, California and University of Southern California, Los Angeles, California; Commission on Nuclear Medicine and Molecular Imaging. qSpecialty Chair, NYU Clinical Cancer Center, New York, New York.


Palpable Breast Masses

Palpable Breast Masses. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through representation of such organizations on expert panels. Participation on the expert panel does not necessarily imply endorsement of the final document by individual contributors or their respective organization. Reprint requests to: publications@acr.org Palpable Breast Masses Discussion of Procedures by Variant Variant 1: Adult female, 40 years of age or older. Palpable breast mass. Initial imaging. Digital Breast Tomosynthesis Diagnostic Diagnostic digital breast tomosynthesis (DBT) should be used for initial imaging evaluation. A small radio-opaque marker is placed on the skin over the palpable finding to identify its location. Several prior studies have shown the diagnostic accuracy of DBT is equivalent to or better than supplemental diagnostic mammographic views in the workup of women with clinical signs and symptoms and in women recalled from screening [11-14]. The added features of planar imaging and thin-section reconstructions allow further assessment of potential false-positive findings. In a recent study, DBT provided similarly accurate diagnostic results as compared with digital mammography (DM) in women with palpable breast masses for detecting breast cancer using either combination DM with DBT (DM/DBT) or DM alone [15]. Several small studies, which specifically included women presenting with clinical symptoms including palpable lumps, demonstrated increased accuracy on combination DM/DBT compared with DM alone [13,16,17]. Additionally, it was demonstrated that DBT may improve lesion detection and characterization with higher conspicuity scores as compared with conventional DM imaging, particularly for cancers presenting as spiculated masses and distortions [17].


Palpable Breast Masses

Palpable Breast Masses. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is not useful as the initial imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated There is no relevant literature to support the use of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET breast dedicated in the initial evaluation of a woman presenting with a palpable mass [2]. In several series evaluating palpable breast abnormalities [18-20], the sensitivity of mammography alone was 86% to 91%. Mammography likely does not need to be repeated if it was performed within the past 6 months [21]. This Palpable Breast Masses modality may be particularly useful in women with almost entirely fatty breasts, in which mammography alone was shown to have a high sensitivity (96%) and specificity (93%) in the evaluation of palpable breast masses [22]. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is not useful as the initial imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast There is no relevant literature to support the use of MRI breast with or without intravenous (IV) contrast in the initial evaluation of a woman presenting with a palpable mass [2,23-25]. Sestamibi MBI There is no relevant literature to support the use of Tc-99m sestamibi molecular breast imaging (MBI) in the initial evaluation of a woman presenting with a palpable mass. US Breast US may be considered as an initial means of imaging if the patient has had a recent negative mammogram within the past 6 months. In a study of women presenting with a palpable breast mass with a negative mammogram within the previous 6 to 12 months, US detected a finding in 50.3% of 311 cases, whereas repeat mammography detected a change in 12.9% of cases [21].


Palpable Breast Masses

Palpable Breast Masses. US is more frequently used following DBT/mammography in this age group [2,26] (see Variants 2, 3, and 5). The negative predictive value of mammography with US in the context of a palpable mass ranges from 97.4% to 100% [7-9]. Variant 2: Adult female, 40 years of age or older. Palpable breast mass. Mammography findings are suspicious or highly suggestive of malignancy (BI-RADS 4 or 5). Next imaging study. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated as the next step in evaluating a palpable mass in the context of a suspicious mammographic finding [2]. Image-Guided Core Biopsy Breast It is preferable for imaging to occur before biopsy because changes related to the biopsy may confuse, alter, obscure, and/or limit image interpretation. If a mammographically suspicious lesion is identified that correlates with the palpable mass, US is recommended as the next step in evaluation before image-guided core biopsy is pursued. However, the lack of sonographic correlate should not deter biopsy of a suspicious mammographic or DBT abnormality in this setting. Core biopsy is superior to FNAB in terms of sensitivity, specificity, and correct histological grading of palpable masses [27]. In addition, core biopsy allows for ready evaluation of tumor receptor status. When a mammographically or DBT-detected suspicious lesion is identified that correlates with a palpable mass, biopsy is warranted. If a lesion is only identified on mammography or DBT, mammographically or DBT- guided core biopsy may be pursued [28,29]. If the lesion can be seen with US, US-guided biopsy may be pursued [30]. At image-guided biopsy, a marker clip is placed, and a postbiopsy diagnostic mammogram confirms that the US and mammographic findings correlate. Similarly, a postbiopsy DBT confirms that the US and DBT findings correlate.


Palpable Breast Masses

Palpable Breast Masses. US-guided core biopsy is also usually more easily tolerated because of a lack of breast compression and may allow biopsy of lesions difficult to access stereotactically (eg, far posterior lesions or axillary lesions) [30]. Image-Guided Fine Needle Aspiration Breast It is preferable for imaging to occur before biopsy because changes related to the biopsy may confuse, alter, obscure, and/or limit image interpretation. If a mammographically suspicious lesion is identified that correlates with the palpable mass, US is recommended as the next step in evaluation before image-guided FNA is pursued. However, the lack of sonographic correlate should not deter biopsy of a suspicious mammographic or DBT abnormality in this setting. Core biopsy is superior to FNAB in terms of sensitivity, specificity, and correct histological grading of palpable masses [27]. In addition, core biopsy allows for ready evaluation of tumor receptor status. An additional consideration of FNAB over a core biopsy may be the faster turnover time for a pathology diagnosis without a difference in time to treatment [31]. At US-guided FNA, a marker clip is placed and a postprocedure mammogram confirms that the US and mammographic findings correlate. Similarly, a postprocedure DBT confirms that the US and DBT findings correlate. Palpable Breast Masses MRI Breast There is no relevant literature to support the use of MRI of the breast with or without IV contrast as the next step in evaluating a palpable mass in the context of a suspicious mammographic finding [2,23-25]. If malignancy is subsequently established by biopsy, MRI may be useful in delineating extent of disease in certain circumstances [32]. Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI as the next step in evaluating a palpable mass in the context of a suspicious mammographic finding. US Breast US may be helpful in characterizing a suspicious mammographic finding [33].


Palpable Breast Masses

Palpable Breast Masses. In a study of women presenting with palpable breast thickening, the sensitivity of diagnostic mammography for invasive cancer detection was 60%, whereas the sensitivity of US alone was 100% [34]. Breast US should be performed using a high-resolution, real-time linear array scanner with an adjustable focal zone and a transducer with a minimum center frequency of 12 MHz [35]. Some mammographers also perform screening US of the remainder of the ipsilateral breast and the contralateral breast in the setting of a suspicious finding [33]. If there is no sonographic correlate for a suspicious mammographic finding, tissue sampling (stereotactic biopsy) should be guided by the suspicious mammographic finding. If there is no sonographic correlate for a suspicious DBT finding, tissue sampling (tomosynthesis-guided biopsy) should be guided by the suspicious DBT finding. Image-Guided Core Biopsy Breast If a palpable mass has probably benign features as identified on mammogram and/or US, imaging follow-up may be appropriate. However, if a mass is new on imaging or increasing by >20% in volume or >20% in each diameter in a 6-month period, the mass is considered suspicious, and image-guided biopsy is recommended [36]. Core biopsy is superior to FNAB in terms of sensitivity, specificity, and correct histological grading of palpable masses [27]. In addition, there are certain cases in which biopsy may be performed even on probably benign lesions. For example, BI-RADS 3 lesions in high-risk patients, patients awaiting organ transplant, patients with known synchronous cancers, or patients trying to get pregnant may be appropriate for tissue sampling. In addition, situations in which biopsy may alleviate extreme patient anxiety may prompt tissue sampling [30,37]. If an image-guided biopsy is pursued, a marker clip is placed and a postbiopsy mammogram/DBT confirms that the clip placement and mammographic/DBT findings correlate.


Palpable Breast Masses

Palpable Breast Masses. Image-Guided Fine Needle Aspiration Breast If a palpable mass has probably benign features as identified on mammogram and/or US, imaging follow-up may be appropriate. However, if a mass is new on imaging or increasing by >20% in volume or >20% in each diameter in a 6-month period, image-guided biopsy is recommended [36]. In addition, there are certain cases in which biopsy may be performed even on probably benign lesions. For example, BI-RADS 3 lesions in high-risk patients, patients awaiting organ transplant, patients with known synchronous cancers, or patients trying to get pregnant may be appropriate for tissue sampling. In addition, situations in which biopsy may alleviate extreme patient anxiety may prompt tissue sampling [30,37]. Large series have demonstrated core biopsy is superior to FNAB in terms of sensitivity, specificity, and correct histological grading of palpable masses [27]. In addition, core biopsy allows for ready evaluation of tumor receptor status. FNAB; however, may allow a faster turnover time as compared with core biopsy for a pathology diagnosis without a difference in time to treatment [31]. At image-guided FNA, a marker clip is placed and a postprocedure mammogram/DBT confirms that the marker clip and mammographic/DBT findings correlate. Palpable Breast Masses Variant 4: Adult female, 40 years of age or older. Palpable breast mass. Mammography findings are benign (BI-RADS 2) at the site of palpable mass. Next imaging study. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated as the next step in evaluating a palpable mass in the context of a benign mammographic finding [2]. Image-Guided Core Biopsy Breast There is no relevant literature to support the use of image-guided core biopsy breast as the next step in evaluating a palpable mass in the context of a benign mammographic finding.


Palpable Breast Masses

Palpable Breast Masses. Image-Guided Fine Needle Aspiration Breast There is no relevant literature to support the use of image-guided FNAB as the next step in evaluating a palpable mass in the context of a benign mammographic finding. However, image-guided aspiration can be considered for symptomatic relief of a palpable simple cyst. MRI Breast There is no relevant literature to support the use of MRI of the breast with or without IV contrast of the breast as the next step in evaluating a palpable mass in the context of a benign mammographic finding. Sestamibi MBI There is no relevant literature to support the use of Tc-99m sestamibi MBI as the next step in evaluating a palpable mass in the context of a benign mammographic finding. US Breast When the mammogram shows a definite benign mass (eg, lymph node, hamartoma, lipoma, calcified fibroadenoma, or oil cyst), US is not necessary as long as the benign mass identified on mammography is a definitive correlate of the clinical finding. If correlation between the mammographic finding and the palpable lesion is uncertain, US is useful. US is preferably targeted specifically to the palpable finding [33]. When both mammography and US are negative or benign in the evaluation of a palpable breast mass, the negative predictive value exceeds 97% [8,9,38]. Together, these imaging modalities can be reassuring when the physical examination is not highly suspicious and clinical follow-up is planned. However, a suspicious physical examination should prompt biopsy regardless of benign imaging findings [38]. Variant 5: Adult female, 40 years of age or older. Palpable breast mass. Mammography findings are negative (BI-RADS 1). Next imaging study. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated as the next step in the evaluation of a woman presenting with a negative mammogram and a palpable mass [2].


Palpable Breast Masses

Palpable Breast Masses. Image-Guided Core Biopsy Breast There is no relevant literature to support the use of image-guided core biopsy as the next step in the evaluation of a woman presenting with a negative mammogram and a palpable mass. US should be performed, and if a suspicious correlate is identified, then US-guided core biopsy is recommended. However, a suspicious physical examination should prompt biopsy guided by palpation, regardless of negative imaging findings [38]. Image-Guided Fine Needle Aspiration Breast There is no relevant literature to support the use of image-guided FNAB as the next step in the evaluation of a woman presenting with a negative mammogram and a palpable mass. US should be performed, and if a suspicious correlate is identified, then US-guided core biopsy is recommended. However, a suspicious physical examination should prompt biopsy guided by palpation, regardless of negative imaging findings [38]. MRI Breast MRI of the breast with or without IV contrast for women with a palpable mass and negative mammography is not recommended as the next imaging study [2,23-25]. US should be performed next [8,9,19]. Palpable Breast Masses Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI as the next step in the evaluation of a woman presenting with a negative mammogram and a palpable mass. US Breast A major advantage of US is the ability to directly correlate the clinical and imaging findings. The use of multiple modalities in diagnosing palpable masses has been advocated as a measure to increase the true-positive rate. In 3 series evaluating palpable breast abnormalities [18-20], the sensitivity of mammography was 86% to 91%. The addition of US detects 93% to 100% of cancers [8,9,19]. The addition of US to mammography may also improve detection of a benign etiology for a palpable finding and may also identify lesions that are mammographically occult [26]. In a series, 40% of benign palpable masses were identified only on US [20].


Palpable Breast Masses

Palpable Breast Masses. In another study of 375 palpable masses in 320 women, 68.8% of the masses (n = 258) were only identified with US and were typically oval (n = 275, 73.3%) and hypoechoic (n = 336 in 372 US examinations, 90.3%) [39]. When both mammography and US are negative or benign in the evaluation of a palpable breast mass, the negative predictive value is very high, more than 97% [8,9,38,40]. Together, these imaging modalities can be reassuring when the physical examination is not highly suspicious and clinical follow-up is planned. If almost entirely fatty tissue is identified in the palpable region of concern, US may not be necessary [2]. In a study that included 323 palpable masses in 271 women with almost entirely fatty tissue on diagnostic mammography, mammography alone yielded a negative predictive value of 99.6% [22]. Of the 294 (91%) of women with almost entirely fatty breasts who also underwent targeted US for the evaluation of palpable symptoms, US yielded 11 false- positives and 8 benign correlates at sites with no mammographic findings [22]. Variant 6: Adult female, younger than 30 years of age. Palpable breast mass. Initial imaging. Digital Breast Tomosynthesis Diagnostic Because of the low incidence of breast cancer (<1%) in younger women, the recommended initial imaging differs from older patients [41-44]. Younger women tend to have relatively denser breast tissue [45], which is associated with decreased mammographic/DBT sensitivity [46]. DBT is not useful as the initial imaging modality in younger women. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is not useful as the initial imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated as the initial imaging workup in women <30 years of age with a palpable mass [2].


Palpable Breast Masses

Palpable Breast Masses. Image-Guided Core Biopsy Breast There is no relevant literature to support the use of image-guided core biopsy as the initial imaging workup in women <30 years of age with a palpable mass. Image-Guided Fine Needle Aspiration Breast There is no relevant literature to support the use of image-guided FNAB as the initial imaging workup in women <30 years of age with a palpable mass. Mammography Diagnostic Because of the low incidence of breast cancer (<1%) in younger women, the recommended initial imaging differs from older patients [41-44]. Younger women tend to have relatively denser breast tissue [45], which is associated with decreased mammographic/DBT sensitivity [46]. Most benign lesions in young women are not visualized on mammography [41,43]. Diagnostic mammography is not useful as the initial imaging modality in younger women. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is not useful as the initial imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. Palpable Breast Masses MRI Breast There is no relevant literature to support the use of the use of MRI of the breast with or without IV contrast as the initial imaging workup in women <30 years of age with a palpable mass [2,23-25]. Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI as the initial imaging workup in women <30 years of age with a palpable mass. Variant 7: Adult female, younger than 30 years of age. Palpable breast mass. US findings are suspicious or highly suggestive of malignancy (BI-RADS 4 or 5). Next imaging study. Digital Breast Tomosynthesis Diagnostic DBT may be useful in a woman <30 years of age with a suspicious sonographic finding that correlates to a palpable mass.


Palpable Breast Masses

Palpable Breast Masses. DBT may demonstrate findings not readily detected at US (calcifications or subtle architectural distortion); this may provide a more accurate assessment of the extent of disease in the ipsilateral breast and can identify contralateral lesions as well. In addition, DBT may have relatively high diagnostic accuracy in dense breast tissue, often encountered in younger patients [48,49]. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is not useful as the next imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated as the next step in evaluating a palpable mass with suspicious sonographic features in women <30 years of age [2]. Image-Guided Core Biopsy Breast If a suspicious mass has been identified on US, tissue sampling (US guided) is warranted. It may be appropriate to proceed directly to image-guided biopsy if a palpable lesion has suspicious features on US followed by placement of a biopsy clip. If US findings are particularly worrisome for malignancy, diagnostic mammography or DBT may be performed prior to tissue sampling to delineate disease extent (eg, calcifications extending beyond the margins of the US-identified solid mass) and identify any additional suspicious findings in the ipsilateral or contralateral breast. Core-needle biopsy has been shown in large series to be superior to FNA in terms of sensitivity, specificity, and correct histological grading [27]. Some practices have had good results using FNAB, but this may be facility specific, and a lower threshold for radiologic-pathologic discordance may need to be applied [50,51]. Image-Guided Fine Needle Aspiration Breast If a suspicious mass has been identified on US, tissue sampling (US guided) is warranted.


Palpable Breast Masses

Palpable Breast Masses. It may be appropriate to proceed directly to image-guided biopsy if a palpable lesion has suspicious features on US. If US findings are particularly worrisome for malignancy, diagnostic mammography or DBT may be performed before tissue sampling to delineate disease extent (eg, calcifications extending beyond the margins of the US-identified solid mass) and identify any additional suspicious findings in the ipsilateral or contralateral breast. Core-needle biopsy has been shown in large series to be superior to FNA in terms of sensitivity, specificity, and correct histological grading [27]. Some practices have had good results using FNAB, but this may be facility specific, and a lower threshold for radiologic-pathologic discordance may need to be applied [50,51]. US-guided FNAB may be preferred over core biopsy in rare situations but should be used judiciously. Palpable Breast Masses Mammography Diagnostic Mammography may be useful in a woman <30 years of age with a suspicious sonographic finding that correlates to a palpable mass. If US findings are particularly worrisome for malignancy, mammography diagnostic or diagnostic DBT would usually be performed before tissue sampling to identify any additional suspicious findings and/or delineate the extent of disease (eg, calcifications extending beyond the margins of the US-identified solid mass) in the ipsilateral breast. Mammography diagnostic is recommended as a prebiopsy assessment in cases in which cancer is strongly suspected clinically [41]. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is not useful as the next imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast There is no relevant literature to support the use of the use of MRI of the breast with or without IV contrast as the next step in evaluating a palpable mass with suspicious sonographic features in women <30 years of age [2,23-25].


Palpable Breast Masses

Palpable Breast Masses. Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI as the next step in evaluating a palpable mass with suspicious sonographic features in women <30 years of age. Variant 8: Adult female, younger than 30 years of age. Palpable breast mass. US findings probably benign (BI-RADS 3). Next imaging study. Digital Breast Tomosynthesis Diagnostic If a correlate for a palpable mass has been identified on US and is probably benign, there is no indication for DBT to further evaluate the palpable mass in women <30 years of age. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is unnecessary for imaging surveillance. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated There is no relevant literature to support the use of FDG-PET breast dedicated in women <30 years of age with probably benign sonographic findings in the setting of a palpable mass [2]. Image-Guided Core Biopsy Breast If a palpable mass has probably benign features as identified on US, US follow-up is recommended. However, image-guided core biopsy may be performed after complete imaging assessment in some cases. For example, BI- RADS 3 lesions in high-risk patients, patients awaiting organ transplant, patients with known synchronous cancers, or patients trying to get pregnant may be appropriate for biopsy instead of imaging follow-up. In addition, situations in which biopsy may alleviate extreme patient anxiety may prompt tissue sampling and a biopsy marker clip should be placed [30]. Image-Guided Fine Needle Aspiration Breast If a palpable mass has probably benign features as identified on US, US follow-up is recommended. Image-guided FNAB may be performed after complete imaging assessment in some cases.


Palpable Breast Masses

Palpable Breast Masses. For example, BI-RADS 3 lesions in high-risk patients, patients awaiting organ transplant, patients with known synchronous cancers, or patients trying to get pregnant may be appropriate for tissue sampling. In addition, situations in which biopsy may alleviate extreme patient anxiety may prompt tissue sampling, and a biopsy marker clip should be placed [30]. However, large series demonstrate that core biopsy is superior to FNAB in terms of sensitivity, specificity, and correct histological grading of palpable masses [27]. In addition, core biopsy allows for ready evaluation of tumor receptor status. US-guided FNAB may be preferred in rare situations (lesion abuts an implant). Mammography Diagnostic If a correlate for a palpable mass has been identified on US and is probably benign, there is no indication for diagnostic mammography to further evaluate the palpable mass in women <30 years of age. Palpable Breast Masses Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is unnecessary for imaging surveillance. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast There is no relevant literature to support the use of the use of MRI of the breast with or without IV contrast in women <30 years of age with probably benign sonographic findings in the setting of a palpable mass [2,23-25]. Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI in women <30 years of age with probably benign sonographic findings in the setting of a palpable mass. Variant 9: Adult female, younger than 30 years of age. Palpable breast mass. US findings benign (BI-RADS 2). Next imaging study. Digital Breast Tomosynthesis Diagnostic If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for further evaluation with diagnostic DBT in women <30 years of age.


Palpable Breast Masses

Palpable Breast Masses. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is unnecessary for confirmation of benignity. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for FDG- PET breast dedicated in women <30 years of age [2]. Image-Guided Core Biopsy Breast If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for tissue sampling. The likelihood of a palpable mass in a young woman that is benign on both clinical examination and US resulting in a cancer is extremely low; one study prospectively evaluating US-guided core biopsy in 248 young women <25 years of age with clinically benign masses and predominantly benign findings found no cancers in this group [52]. Image-Guided Fine Needle Aspiration Breast If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for image- guided FNAB in women <30 years of age. Mammography Diagnostic If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for further evaluation with diagnostic mammography in women <30 years of age. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is unnecessary for confirmation of benignity. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no role for MRI of the breast with or without IV contrast in women <30 years of age [2,23-25].


Palpable Breast Masses

Palpable Breast Masses. Sestamibi MBI If a benign entity has been found on US and is the definitive correlate for a palpable mass, there is no evidence for Tc-99m sestamibi MBI in women <30 years of age. Palpable Breast Masses age, if physical examination is highly suspicious and DBT and US are negative, tissue sampling with core biopsy or surgical biopsy is warranted. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is not useful as the next imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. FDG-PET Breast Dedicated There is no relevant literature to support the use of the use of FDG-PET breast dedicated in women <30 years of age with negative US findings [2]. Image-Guided Core Biopsy Breast There is no relevant literature to support the use of the use of image-guided core biopsy in women <30 years of age with negative US findings. Image-Guided Fine Needle Aspiration Breast There is no relevant literature to support the use of the use of image-guided FNAB in women <30 years of age with negative US findings. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is not useful as the next imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast There is no relevant literature to support the use of the use of MRI of the breast with or without IV contrast in women in women <30 years of age with negative US findings [2,23-25]. Sestamibi MBI There is no relevant literature to support the use of the use of Tc-99m sestamibi MBI in women <30 years of age with negative US findings. Digital Breast Tomosynthesis Screening In women presenting with signs or symptoms, including a palpable breast mass, screening DBT, with or without DM, is not useful as the initial imaging study.


Palpable Breast Masses

Palpable Breast Masses. Screening mammography is provided to women without signs or symptoms of breast disease. Palpable Breast Masses FDG-PET Breast Dedicated There is no relevant literature to support the use of the use of FDG-PET breast dedicated in the initial evaluation of women 30 to 39 years of age with a palpable mass [2]. Image-Guided Core Biopsy Breast There is no relevant literature to support the use of the use of image-guided core biopsy in the initial evaluation of women 30 to 39 years of age with a palpable mass. Image-Guided Fine Needle Aspiration Breast There is no relevant literature to support the use of the use of image-guided FNAB in the initial evaluation of women 30 to 39 years of age with a palpable mass. One study of 1,208 women 30 to 39 years of age presenting with focal breast symptoms found a higher sensitivity for US compared with mammography (95.7% versus 60.9%) but with a similar specificity (89.2% and 94.4%, respectively), negative predictive value (99.9% and 99.2%, respectively), and positive predictive value (13.2% and 18.4%, respectively) [40]. Mammography Screening In women presenting with signs or symptoms, including a palpable breast mass, screening mammography is not useful as the initial imaging study. Screening mammography is provided to women without signs or symptoms of breast disease. MRI Breast There is no relevant literature to support the use of MRI of the breast with or without IV contrast in the initial evaluation of women 30 to 39 years of age with palpable mass [2,23-25]. Sestamibi MBI There is no relevant literature to support the use of Tc-99m sestamibi MBI in the initial evaluation of women 30 to 39 years of age with palpable mass. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.


Acute Onset of Scrotal Pain Without Trauma Without Antecedent Mass.  Introduction/Background The acute scrotum is a medical emergency defined as scrotal pain, swelling and redness of acute onset, from minutes to 1 to 2 days [1] and comprises at least 0.5% of all emergency department visits [2]. Etiologies of acute scrotum are numerous, and rapid accurate diagnosis is essential to appropriately triage potentially surgical and irreversible conditions from patients for whom conservative management is sufficient. Diagnostic considerations include testicular torsion, torsion of testicular appendage, epididymoorchitis, epididymitis, idiopathic scrotal edema, hydrocele, inflammation of the tunica vaginalis, trauma, testicular tumors, epididymal cysts, Fournier gangrene, scrotal abscess, and strangulated inguinal hernia [3-6]. Torsion of a testicular appendage, epididymitis, and testicular torsion are the three most common causes of acute scrotal pain and account for approximately 85% to 90% of cases [7]. Large differential diagnoses and overlapping clinical presentation make the acute scrotum a diagnostic challenge. Acute epididymoorchitis or epididymitis is the most common cause of acute scrotum in adolescent boys and adults [8,9]. In 2002, epididymitis or epididymoorchitis accounted for 1 in 44 outpatient visits in men 18 to 50 years of age [9,10]. Although uncommon in pediatric populations, it can be associated with urinary tract infections and/or structural and functional abnormalities of the urinary tract [11,12]. Epididymitis has a more insidious and gradual onset than testicular torsion. As inflammation and edema progress, a reactive hydrocele may develop making it difficult to differentiate from testicular torsion. Clinically, scrotal pain associated with epididymitis is usually relieved when the testes are elevated over the symphysis pubis (the Prehn sign) [8,13].


Acute Onset of Scrotal Pain Without Trauma Without Antecedent Mass. This sign may help clinically differentiate between epididymitis and torsion of the spermatic cord, in which scrotal pain is not lessened with this maneuver [14]. Testicular torsion is defined as twisting of the spermatic cord, compromising blood flow to and from the testes [2]. It is a surgical emergency with a bimodal distribution presenting more frequently in neonates and postpubertal boys than in adults, although it can occur at any age [19]. It has an estimated reported yearly incidence ranging from 2.9 to 3.8 in 100,000 boys <18 years of age [20,21]. Prompt recognition and surgical exploration within 6 to 8 hours after symptom onset is essential to prevent testicular loss [22]. A validated [23-26], clinical risk scoring system, Testicular Workup for Ischemia and Suspected Torsion Score, has shown high positive predictive value; however, it has not been widely adopted [20]. Special Imaging Considerations Contrast-enhanced ultrasound (US) has expanded considerably in the last few decades and has proved to be a useful tool in determining the presence or absence of organ perfusion by improving the signal-to-noise ratio of tissue Reprint requests to: publications@acr.org Acute Onset of Scrotal Pain Microvascular imaging US is a new Doppler module that better differentiates slow flow via mathematical algorithms based on signal amplitude width [33], by separating low frequency of static tissue artifacts from low frequencies of very weak flow. Microvascular imaging obtains a higher resolution by separating the Doppler components of the 2 different sources [34]. Shear wave elastography (SWE) is a recently developed technique capable of quantitatively evaluating soft tissue stiffness [35,36]. This serves as a surrogate marker for tissue composition.


Acute Onset of Scrotal Pain Without Trauma Without Antecedent Mass. Studies have shown that SWE values of testicular parenchyma increase during testicular torsion; however, there are limited studies showing whether these changes can be distinguished from other pathologies such as acute inflammation [36]. OR Discussion of Procedures by Variant Variant 1: Adult or child. Acute onset of scrotal pain. Without trauma, without antecedent mass. Initial imaging. This discussion will be limited to patients with acute pain, without history of trauma, and no history of antecedent or known scrotal or testicular mass because these scenarios are discussed elsewhere [37,38]. CT Pelvis With IV Contrast CT of the pelvis with intravenous (IV) contrast is not routinely used as an initial imaging modality for the evaluation of acute scrotal pain without trauma and without antecedent mass. There is no relevant literature regarding the use of CT of the pelvis in these patients. However, in the setting of Fourniers gangrene, CT can lead to early diagnosis with accurate assessment of disease extent [3]. CT Pelvis Without and With IV Contrast CT of the pelvis without and with IV contrast is not routinely used as an initial imaging modality for the evaluation of acute scrotal pain without trauma and without antecedent mass. There is no relevant literature regarding the use of CT of the pelvis in these patients. CT Pelvis Without IV Contrast CT of the pelvis without IV contrast is not routinely used as an initial imaging modality for the evaluation of acute scrotal pain without trauma and without antecedent mass. There is no relevant literature regarding the use of CT of the pelvis in these patients. MRI Pelvis (Scrotum) Without and With IV Contrast MRI of the pelvis without and with IV contrast is not routinely used as an initial imaging modality for the evaluation of acute scrotal pain without trauma and without antecedent mass.


Acute Onset of Scrotal Pain Without Trauma Without Antecedent Mass. However, it may be used as a problem solving second-line modality when findings on US are indeterminate [39,40]. Diagnoses such as minor tunica albuginea tears and blunt scrotal trauma, chronic epididymoorchitis, and partial or intermittent torsion may sometimes be missed on US [39,41,42]. Due to its larger field of view and multiplanar capabilities, MRI of the scrotum provides excellent anatomical detail of all scrotal contents and inguinal region. In addition, MRI provides high soft-tissue contrast, high sensitivity for contrast enhancement, and functional information. These features contribute to a more precise treatment strategy, reducing unwarranted surgical exploration [39,40,43-47]. Limitations of MRI in the Acute Onset of Scrotal Pain evaluation of acute scrotum include long scan time, potentially delaying surgical exploration, and possible need for anesthesia in pediatric patients [39,40,48] and patients with claustrophobia or anxiety. MRI has high accuracy in establishing the diagnosis of segmental testicular infarction [39,49-51]. Segmental testicular infarction is an uncommon entity that can mimic a small hypovascular tumor on US [50,52-55]. MRI findings include a T2 hypointense, avascular lesion with marked rim enhancement. Intralesional hyperintense T1 signal may coexist due to hemorrhagic products [39,44,50,55-57]. Diffusion-weighted imaging and apparent diffusion coefficient (ADC) provide qualitative and quantitative analysis by adding functional information about molecular activity and cellular function, in addition to the morphological information provided by other MRI sequences, like dynamic contrast-enhanced and T2- and T2*-weighted images [60,61]. Diffusion-weighted imaging and ADC images demonstrate lower ADC values of the torsed testicle compared to the normal contralateral testicle [62].


Acute Onset of Scrotal Pain Without Trauma Without Antecedent Mass. MRI Pelvis (Scrotum) Without IV Contrast MRI of the pelvis without IV contrast is not routinely used as an initial imaging modality for the evaluation of acute scrotal pain without trauma and without antecedent mass. There is no relevant literature regarding the use of MRI of the pelvis without IV contrast in these patients. Nuclear Medicine Scan Scrotum Radionuclide scrotal imaging (RNSI) has been replaced by Doppler US as the primary imaging modality for evaluation of the acute scrotum. RSNI has a reported sensitivity and specificity for differentiation between testicular torsion and epididymoorchitis from 89% to 98% and 90% to 100%, respectively [68,69]. RSNI is limited by technical challenges in children whose small genitalia are difficult to image with radiotracers. RNSI also can have photon-deficient areas secondary to hydrocele, spermatocele, and inguinal hernias, which can be erroneously diagnosed as avascular testis [70]. US Duplex Doppler Scrotum Spectral analysis of the Doppler waveform allows a quantitative assessment of organ perfusion. Acute Onset of Scrotal Pain contralateral testicle or a different region within the same testicle. Variability of the amplitude was the most common abnormality, followed by reversal of diastolic flow [6]. Additional characteristic spectral Doppler waveforms seen in partial testicular torsion include monophasic waveform, tardus-parvus morphology, and spectral Doppler waveform variations within the same testis, all worrisome for underlying ischemia. Spectral Doppler analysis should be performed in the upper, mid, and lower poles of each testicle [6,72,74]. US Scrotum US is the established first-line imaging modality for acute scrotal disease [75] and can be used to diagnose most scrotal disorders when combined with clinical history and physical examination. US is generally well tolerated and widely available, making it ideal for scrotal evaluation.


Tracheobronchial Disease

Tracheobronchial Disease.  Bronchiectasis is defined as irreversible abnormal bronchial dilatation, with patients most commonly presenting with chronic productive cough. Although a wide range of congenital and acquired conditions can be associated with bronchiectasis, a common etiologic pathway is thought to be impairment of normal bronchial clearance and airway immune mechanisms, resulting in recurrent infections and chronic bronchial inflammation that cause bronchial injury and dilatation [9,10]. The prevalence of bronchiectasis has increased worldwide over the last few decades; in the United States, prevalence has been estimated as approximately 139 per 100,000 individuals [9]. Treatment includes preventive airway clearance therapies, anti-inflammatory agents, prophylactic or therapeutic antibiotics, and, in severe cases, surgical resection or lung transplantation. Special Imaging Considerations In cases of tracheal stenosis and central airway lesions in general, special CT reformatting techniques such as 2-D multiplanar, 3-D volume-rendered, and virtual bronchoscopic images may be helpful for illustration of findings and preprocedural planning [11-13]. For example, coronal and sagittal 2-D reformatted images and 3-D volume reformatted images can depict the craniocaudal extent of lesions and distance from landmarks such as the vocal cords and carina, and virtual bronchoscopic images can illustrate the expected endoluminal appearance of lesions and provide guidance for bronchoscopy and procedures by demonstrating local airway anatomy. Minimum intensity projection reformatted images can also display central airway abnormalities and bronchiectasis [10]. Modern multidetector CT can be used to image the entire trachea at end expiration or during forced expiration (dynamic expiratory imaging). More recently, 320-row multidetector CT scanners have enabled cinematic 4-D volumetric images of the trachea, allowing time-resolved coverage of the entire trachea throughout an inspiratory/expiratory cycle [14,15].


Tracheobronchial Disease

Tracheobronchial Disease. Low-dose volumetric CT using 40 to 80 mA is comparable to standard higher- Reprint requests to: publications@acr.org Tracheobronchial Disease dose techniques in demonstrating degree of trachea collapse [16], and low-dose techniques have been widely adopted for dynamic expiratory imaging assessment of ECAC [17,18]. Optimal evaluation of the airways requires thin-section imaging with a slice thickness of 1.5 mm or thinner. Larger slice thicknesses cause partial volume averaging that can obscure airway anatomy and airway lesions. Adequate breath holding at inspiration is also important, because respiratory motion can also obscure airway lesions and can also cause an erroneous impression of bronchiectasis caused by volume averaging and image blurring. OR Discussion of Procedures by Variant Variant 1: Adult. Clinically suspected tracheal or bronchial stenosis. Initial imaging. CT Chest With IV Contrast Chest CT is widely used for first-line imaging evaluation of central airway pathology such as masses, thickening, and stenosis. CT with intravenous (IV) contrast provides the advantage of evaluation of enhancement characteristics and optimal evaluation of hilar and mediastinal adenopathy [19], however, relevant studies comparing contrast- enhanced CT with unenhanced CT are lacking. CT has shown a high correlation with findings at bronchoscopy and offers additional advantages by depicting degree of stenosis, extraluminal involvement of lesions, and extension to adjacent structures [19-21]. CT allows assessment of the location, shape, dimensions, mural extent, and attenuation characteristics of tumors of the large airways and detection of intrathoracic disease in cases of malignancy [19,20]. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast in the initial evaluation of suspected tracheal stenosis.


Tracheobronchial Disease

Tracheobronchial Disease. CT Chest Without IV Contrast Chest CT is widely used for first-line imaging evaluation of central airway pathology such as masses, thickening, and stenosis. CT without IV contrast readily depicts central airway lesions, thickening, and stenosis. CT has shown high correlation with findings at bronchoscopy and offers additional advantages by depicting degree of stenosis, extraluminal involvement of lesions, and extension to adjacent structures [20,21]. CT allows assessment of the location, shape, dimensions, mural extent, and attenuation characteristics of tumors of the large airways and detection of intrathoracic disease in cases of malignancy [19,20]. CT Neck and Chest With IV Contrast There is no relevant literature to support the use of neck and chest CT with IV contrast in the initial evaluation of suspected tracheal stenosis. However, combined neck and chest CT with IV contrast can be performed for Tracheobronchial Disease assessment of suspected tracheal lesions and stenosis, especially for diseases that can involve the subglottic trachea, such as diffuse tracheal diseases and suspected or known malignancies of the neck. Chest CT protocols to evaluate tracheal stenosis often prescribe z-axis coverage through the lower neck. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast in the initial evaluation of suspected tracheal stenosis. CT Neck and Chest Without IV Contrast There is no relevant literature to support the use of neck and chest CT without IV contrast in the initial evaluation of suspected tracheal stenosis. However, combined neck and chest CT without IV contrast may be performed for assessment of suspected tracheal lesions and stenosis, especially for diseases that can involve the subglottic trachea, such as diffuse tracheal diseases and suspected or known malignancies of the neck.


Tracheobronchial Disease

Tracheobronchial Disease. Chest CT protocols to evaluate tracheal stenosis often prescribe z-axis coverage through the lower neck. CT Neck With IV Contrast Neck CT with IV contrast may occasionally be performed as a targeted assessment of known lesions within the superior trachea, including primary neck malignancies with tracheal involvement. However, the limited z-axis coverage of neck CT risks exclusion of the full extent of tracheal disease. More commonly, neck CT may be performed as part of a combined neck and chest CT for assessment of suspected tracheal lesions and stenosis. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast in the initial evaluation of suspected tracheal stenosis. CT Neck Without IV Contrast Neck CT without IV contrast may occasionally be performed as a targeted assessment of known lesions within the superior trachea, including primary neck malignancies with tracheal involvement. However, the limited z-axis coverage of neck CT risks exclusion of the full extent of tracheal disease. More commonly, neck CT may be performed as part of a combined neck and chest CT for assessment of suspected tracheal lesions and stenosis. CTA Chest With IV Contrast Chest CT angiography (CTA) with IV contrast may be used in evaluation of suspected tracheal stenosis in the setting of extrinsic compression due to a vascular cause, such as aberrant vessel or aneurysm. However, there is no relevant evidence comparing chest CTA and standard chest CT with or without IV contrast in initial evaluation of suspected tracheal stenosis. FDG-PET/CT Skull Base To Mid-Thigh Fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT is often used in the initial staging and follow-up of known thoracic malignancies, including tracheal tumors. However, FDG-PET/CT is not usually obtained as the initial imaging assessment of suspected tracheal stenosis.


Tracheobronchial Disease

Tracheobronchial Disease. MRI Chest Without and With IV Contrast Although tracheal imaging can be performed with MRI, including dynamic imaging, this tool has been used mainly as a research tool. MRI Chest Without IV Contrast Although tracheal imaging can be performed with MRI, including dynamic imaging, this tool has been used mainly as a research tool. Radiography Chest Radiography is often performed as initial imaging in patients with respiratory symptoms. Although tracheal stenosis and masses are occasionally incidental findings at chest radiography, the modality is much less sensitive for detection of central airway pathology than cross-sectional imaging. In a study of 41 patients with tumors and nonneoplastic stenosis of the central airways, radiography performed poorly compared to CT in depicting and characterizing lesions [22]. Radiography may be useful as an evaluation of possible complications of central airway disease, such as postobstructive atelectasis or pneumonia. Tracheobronchial Disease Radiography Neck There is no relevant literature to support the use of neck radiography in the initial evaluation of suspected tracheal stenosis. Radiography of the neck may be obtained in patients with suspected upper airway obstruction due to certain infections or foreign bodies. However, it is not routinely used for evaluation of tracheal stenosis. Variant 2: Adult. Tracheal or bronchial stenosis. Pre- or posttreatment assessment. CT Chest With IV Contrast CT of the chest with IV contrast can be used for pretreatment assessment of lesions and stenosis of the large airways and can help determine suitability and type of surgical or nonsurgical treatment approach [24]. However, studies comparing performance of chest CT with IV contrast to chest CT without IV contrast for evaluation of tracheal stenosis and associated lesions are lacking.


Tracheobronchial Disease

Tracheobronchial Disease. A few small studies have documented additional incremental benefits of review of 2-D multiplanar, 3-D reformatted, and VB images, including changes in surgical approach or identification of associated findings such as small fistulae [11]. Chest CT is also used for evaluation of suspected posttreatment complications of tracheal interventions. CT is commonly used for planning for tracheal stent implantation; a study of 69 patients with stenosis due to malignancy used CT to select stent diameter by measuring proximal and distal landing zone diameters and to determine desired stent length by measuring length of the involved segment [25]. A small study of 17 stenoses in 14 patients with postintubation stenosis confirmed at surgery found a detection rate of stenosis of 94% (16 of 17 lesions) of CT with VB and 88% (15 of 17) by rigid bronchoscopy; assessment of length was accurate for 87% of stenotic segments by CT and VB and 73% of segments by rigid bronchoscopy [13]. In a study of contrast-enhanced CT of 46 adenoid cystic carcinomas of the trachea and 36 other tracheal tumors, several imaging characteristics were predictive of poor disease-free survival, including longitudinal length >34 mm, transmural growth, and transverse length >20 mm, although only the latter remained significant in multivariate analysis [19]. A retrospective study of 31 tumors of the trachea or main bronchi compared a combination of pre- and postcontrast CT axial images, volume-rendered, and VB postprocessing techniques with surgical and pathology findings, finding good correlations for tumor locations, morphologies, longitudinal involvement, extent and morphology of stenosis, extramural invasion, and distance from the carina [12]. In a study of 52 patients comparing VB with bronchoscopy, VB had a high sensitivity and accuracy (both 93%) for detection of central airway tumors and had a high sensitivity (90%) and accuracy (96%) for characterization of airway stenosis [26].


Tracheobronchial Disease

Tracheobronchial Disease. However, there is no relevant literature specifically comparing chest CT with IV contrast to chest CT without IV contrast. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast for pre- or posttreatment evaluation of tracheal stenosis. CT Chest Without IV Contrast CT of the chest without IV contrast is widely used for pretreatment assessment of lesions and stenosis of the large airways and can help determine suitability and type of surgical or nonsurgical treatment approach [24]. A few small studies have documented additional incremental benefits of review of 2-D multiplanar, 3-D reformatted, and VB images, including changes in surgical approach or identification of associated findings such as small fistulae [11]. Chest CT is also used for evaluation of suspected posttreatment complications of tracheal interventions. CT is commonly used for planning for tracheal stent implantation; a study of 69 patients with stenosis due to malignancy used CT to select stent diameter by measuring proximal and distal landing zone diameters and to determine desired stent length by measuring length of the involved segment [25]. A small study of 17 stenoses in 14 patients with postintubation stenosis confirmed at surgery found a detection rate of stenosis of 94% (16 of 17 lesions) of CT with VB and 88% (15 of 17) by rigid bronchoscopy; assessment of length was accurate for 87% of stenotic segments by CT and VB and 73% of segments by rigid bronchoscopy [13]. A retrospective study of 31 tumors of the trachea or main bronchi compared a combination of pre- and postcontrast CT axial images, volume-rendered, and VB postprocessing techniques with surgical and pathology findings, finding good correlations for tumor locations, morphologies, longitudinal involvement, extent and morphology of stenosis, extramural invasion, and distance from the carina [12]. In a study of 52 patients comparing VB with bronchoscopy, Tracheobronchial Disease


Tracheobronchial Disease

Tracheobronchial Disease. VB had a high sensitivity and accuracy (both 93%) for detection of central airway tumors and had a high sensitivity (90%) and accuracy (96%) for characterization of airway stenosis [26]. CT Neck and Chest With IV Contrast Combined neck and chest CT with IV contrast can be performed for pre- or posttreatment evaluation of tracheal stenosis, especially for diseases that can involve the subglottic trachea, such as diffuse tracheal diseases and suspected or known malignancies of the neck. Chest CT protocols to evaluate tracheal stenosis often prescribe z- axis coverage through the lower neck. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast for pre- or posttreatment evaluation of tracheal stenosis. CT Neck and Chest Without IV Contrast Combined neck and chest CT without IV contrast can be performed for pre- or posttreatment evaluation of tracheal stenosis, especially for diseases that can involve the subglottic trachea, such as diffuse tracheal diseases and suspected or known malignancies of the neck. Chest CT protocols to evaluate tracheal stenosis often prescribe z- axis coverage through the lower neck. CT Neck With IV Contrast Neck CT with IV contrast may occasionally be performed as a targeted assessment of known lesions within the superior trachea, including primary neck malignancies with tracheal involvement. However, the limited z-axis coverage of neck CT risks exclusion of the full extent of tracheal disease. More commonly, neck CT may be performed as part of a combined neck and chest CT for pre- or posttreatment assessment of tracheal lesions and stenosis. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast for pre- or posttreatment evaluation of tracheal stenosis.


Tracheobronchial Disease

Tracheobronchial Disease. CT Neck Without IV Contrast Neck CT without IV contrast may occasionally be performed as a targeted assessment of known lesions within the superior trachea, including primary neck malignancies with tracheal involvement. However, the limited z-axis coverage of neck CT risks exclusion of the full extent of tracheal disease. More commonly, neck CT may be performed as part of a combined neck and chest CT for pre- or posttreatment assessment of tracheal lesions and stenosis. CTA Chest With IV Contrast Chest CTA with IV contrast may be used in preoperative evaluation of tracheal stenosis in the setting of extrinsic compression due to a vascular cause, such as aberrant vessel or aneurysm. Chest CTA with aortic contrast phase timing may be used in selected cases to evaluate suspected bleeding as a complication of tracheal interventions. MRI Chest Without and With IV Contrast Although tracheal imaging can be performed with MRI, including dynamic imaging, this tool has been used mainly as a research tool. MRI Chest Without IV Contrast Although tracheal imaging can be performed with MRI, including dynamic imaging, this tool has been used mainly as a research tool. Tracheobronchial Disease Radiography Chest There is no relevant literature to support the use of chest radiography for pretreatment evaluation of tracheal stenosis. Although there is no relevant literature to support the routine use of chest radiographs after procedures designed to treat tracheal stenosis, in practice chest radiographs may be obtained to evaluate possible complications such as pneumothorax, excessive pneumomediastinum, or aspiration. Radiography Neck There is no relevant literature to support the use of neck radiography for pre- or posttreatment evaluation of tracheal stenosis. Variant 3: Adult. Clinically suspected tracheomalacia or bronchomalacia. Initial imaging.


Tracheobronchial Disease

Tracheobronchial Disease. CT Chest With IV Contrast There is no relevant literature to support the use of chest CT with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CT Chest Without IV Contrast Chest CT without IV contrast is useful for noninvasive imaging of ECAC, including tracheobronchomalacia and excessive dynamic airway collapse. Chest CT during forced expiration has been widely adopted as the primary imaging protocol because it is more sensitive for detection of ECAC, eliciting greater degrees of expiratory collapse than CT obtained at end expiration [29-31]. In a study of 29 patients with suspected ECAC, forced expiratory dynamic cine imaging showed tracheal collapse >50% at 38% of assessed levels compared to 13% at end-expiratory CT [32]; a study of 67 patients with chronic obstructive pulmonary disease (COPD) showed a mean tracheal collapse of 62% at forced expiratory CT and only 17% at end expiratory CT [31]. Fifty percent area narrowing of the lumen of the trachea on CT at expiration had originally been considered suggestive of ECAC, but a threshold of 70% collapse is now proposed following a study by Boiselle et al [17], finding >50% collapse in 40 of 51 (78%) healthy volunteers. CT Neck and Chest With IV Contrast There is no relevant literature to support the use of neck and chest CT with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia.


Tracheobronchial Disease

Tracheobronchial Disease. CT Neck and Chest Without IV Contrast There is no relevant literature to support performing a full neck CT in this setting, however, z-axis coverage through the lower neck is often prescribed as part of a standard chest CT without IV contrast for evaluation of suspected tracheomalacia or bronchomalacia. CT Neck With IV Contrast There is no relevant literature to support the use of neck CT with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CT Neck Without IV Contrast There is no relevant literature to support the use of neck CT without IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. CTA Chest With IV Contrast There is no relevant literature to support the use of chest CTA for initial evaluation of suspected tracheomalacia or bronchomalacia. Tracheobronchial Disease FDG-PET/CT Skull Base To Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT for initial evaluation of suspected tracheomalacia or bronchomalacia. MRI Chest Without and With IV Contrast There is no relevant literature to support the use of MRI chest without and with IV contrast for initial evaluation of suspected tracheomalacia or bronchomalacia. Radiography Chest Dynamic chest radiography has been proposed for evaluating ECAC but use has been limited to small preliminary research investigations [34]. Chest radiography may be used in the initial evaluation of other pulmonary diseases that may manifest with respiratory symptoms also seen in ECAC. Radiography Neck There is no relevant literature to support the use of neck radiography for initial evaluation of suspected tracheomalacia or bronchomalacia. Variant 4: Adult. Tracheomalacia or bronchomalacia. Pre- or posttreatment assessment.


Tracheobronchial Disease

Tracheobronchial Disease. CT Chest With IV Contrast There is no relevant literature to support the use of chest CT with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. In practice, chest CT may be performed with IV contrast in evaluation of postsurgical complications of procedures used to treat tracheomalacia or bronchomalacia. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. CT Chest Without IV Contrast Evaluation of ECAC with dynamic expiratory CT can change treatment approach in some patients compared with evaluation with bronchoscopy alone and is standardly performed without IV contrast. In one study, a change in planned treatment was performed in 12 of 29 patients with tracheomalacia or bronchomalacia who had previously undergone bronchoscopy, including changes in surgical approach [30]. A small study using inspiratory and dynamic expiratory CT to evaluate 5 patients with tracheomalacia before and after tracheobronchoplasty found a decrease in degree of tracheal collapse after surgery in all participants [35]. Other studies of 18 patients [8] and 16 patients [36] with tracheobronchomalacia using end inspiratory and dynamic expiratory CT showed significant average decreases trachea after tracheobronchoplasty. However, there are no guidelines for performing routine follow up of patients after treatment for ECAC. CT Neck and Chest With IV Contrast Z-axis coverage through the lower neck is often prescribed as part of a standard chest CT with IV contrast for evaluation of suspected tracheomalacia or bronchomalacia, but there is no relevant evidence to support performing a full neck CT in this setting. In clinical practice, neck CT may be performed in conjunction with chest CT to evaluate suspected complications of tracheal interventions.


Tracheobronchial Disease

Tracheobronchial Disease. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. Tracheobronchial Disease CT Neck and Chest Without IV Contrast Z-axis coverage through the lower neck is often prescribed as part of a standard chest CT without IV contrast for evaluation of suspected tracheomalacia or bronchomalacia, but there is no relevant evidence to support performing a full neck CT in this setting. In clinical practice, neck CT may be performed in conjunction with chest CT to evaluate suspected complications of tracheal interventions. CT Neck With IV Contrast There is no relevant literature to support the use of neck CT with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. CT Neck Without IV Contrast There is no relevant literature to support the use of neck CT without IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. CTA Chest With IV Contrast There is no relevant literature to support the use of chest CTA for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. However, chest CTA timed for an aortic phase of contrast may be used in selected cases to evaluate suspected bleeding as a complication of tracheal interventions. FDG-PET/CT Skull Base To Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. MRI Chest Without and With IV Contrast There is no relevant literature to support the use of MRI chest without and with IV contrast for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia.


Tracheobronchial Disease

Tracheobronchial Disease. Radiography Chest Although there is no relevant literature to support the routine use of chest radiographs after procedures designed to treat tracheomalacia or bronchomalacia, in practice, chest radiographs may be obtained to evaluate possible complications such as pneumothorax, excessive pneumomediastinum, or aspiration. Radiography Neck There is no relevant literature to support the use of neck radiography for pre- or posttreatment evaluation of tracheomalacia or bronchomalacia. Variant 5: Adult. Clinically suspected bronchiectasis. Initial imaging. CT Chest With IV Contrast There is no relevant literature to support the use of chest CT with IV contrast for initial evaluation of suspected bronchiectasis. However, bronchiectasis can be detected incidentally on chest CT with IV contrast performed for other indications. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast for initial evaluation of suspected bronchiectasis. Tracheobronchial Disease The 2010 British Thoracic Society guidelines for non-cystic fibrosis (non-CF) bronchiectasis recommend thin- section CT, either conventional high-resolution CT or volumetric thin-slice CT, as the preferred examination for evaluation of suspected bronchiectasis. The guidelines acknowledge that, although certain CT distributions and appearances of bronchiectasis may suggest a particular etiology, in many cases, findings are not pathognomonic, as confirmed by the relatively low reader diagnostic performance in several retrospective CT studies [38-41]. However, CT can play a role in suggesting further clinical evaluation of causes of bronchiectasis and associated findings, such as in prompting testing for nontuberculous mycobacterial infection (NTMB) in the appropriate clinical setting [42]. CT can be used to quantify the extent and severity of bronchiectasis using a variety of techniques and software.


Tracheobronchial Disease

Tracheobronchial Disease. A systematic review of 122 studies found 42 quantitative CT scoring methods in the research literature, including calculation of bronchial-arterial ratios, bronchial diameters, or bronchial surface area [43]. Severity of bronchiectasis at CT correlates with measures of airflow obstruction [40]. A relatively large prospective cohort study of 608 patients with bronchiectasis examined the association between a variety of clinical, laboratory, and CT findings and clinical outcomes; a CT finding of bronchiectasis in at least 3 lobes was associated with poorer outcomes and was incorporated along with several clinical variables into a bronchiectasis severity score with relatively high predictive value for exacerbations, hospitalizations, and mortality in patients with bronchiectasis [44]. A prospective multicenter study of 261 patients with non-CF bronchiectasis found weak but statistically significant correlations between severity and extent of bronchiectasis at CT and forced expiratory volume in one second and forced vital capacity [45]. A study of 277 patients with NTMB found correlations between bronchiectasis (as assessed by semiquantitative scores) and clinical variables such as more frequent exacerbations and lower blood oxygenation [46]. CT Neck and Chest With IV Contrast There is no relevant literature to support the use of neck and chest CT with IV contrast for initial evaluation of suspected bronchiectasis. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast for initial evaluation of suspected bronchiectasis. CT Neck and Chest Without IV Contrast There is no relevant literature to support the use of neck and chest CT without IV contrast for initial evaluation of suspected bronchiectasis. CT Neck With IV Contrast There is no relevant literature to support the use of neck CT with IV contrast for initial evaluation of suspected bronchiectasis.


Tracheobronchial Disease

Tracheobronchial Disease. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast for initial evaluation of suspected bronchiectasis. CT Neck Without IV Contrast There is no relevant literature to support the use of neck CT without IV contrast for initial evaluation of suspected bronchiectasis. CTA Chest With IV Contrast There is no relevant literature to support the use of chest CTA for initial evaluation of suspected bronchiectasis. However, bronchiectasis can be detected incidentally on chest CTA with IV contrast performed for other indications. Tracheobronchial Disease FDG-PET/CT Skull Base To Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT for initial evaluation of suspected bronchiectasis. MRI Chest Without and With IV Contrast There is no relevant literature to support the use of MRI chest without and with IV contrast for initial evaluation of suspected bronchiectasis. MRI Chest Without IV Contrast Limited data exist on the use of MRI without IV contrast in characterization of bronchiectasis. A small study of 23 adults with primary immunodeficiency found MRI inferior to CT in characterizing extent of bronchiectasis but found similar performance of MRI and CT in assessing severity of bronchiectasis, mucous plugging, bronchial wall thickening, and other associated parenchymal findings [47]. An exploratory study of 25 patients showed moderate agreement between MRI and CT scores for imaging findings in mycobacterium avium complex pneumonia, including for bronchiectasis [48]. However, the use of MRI for assessment of bronchiectasis is currently limited mainly to research settings or use in young patients such as those with cystic fibrosis. Radiography Chest Chest radiography is relatively insensitive for detection of bronchiectasis but is often performed as initial imaging in patients with respiratory symptoms that are common in patients with bronchiectasis [9,10].


Tracheobronchial Disease

Tracheobronchial Disease. Chest radiography may be useful for the initial evaluation of the lung parenchyma in conditions associated with bronchiectasis, but it provides limited characterization of severity and morphology of bronchiectasis. The 2010 British Thoracic Society guidelines for non-CF bronchiectasis recommend a baseline chest radiograph in all patients with suspected bronchiectasis but recommend repeat radiographs only if clinically warranted [40]. Radiography Neck There is no relevant literature to support the use of neck radiography for initial evaluation of suspected bronchiectasis. Variant 6: Adult. Bronchiectasis. Assessment of complications or treatment response. CT Chest With IV Contrast There is no relevant literature to support the use of chest CT with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT chest with IV contrast may also be appropriate in the setting of suspected acute infection and associated complications such as abscess or necrosis. CT Chest Without and With IV Contrast There is no relevant literature to support the use of chest CT without and with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Chest Without IV Contrast Chest CT without IV contrast may be used to evaluate complications associated with bronchiectasis, including pneumonia and hemoptysis, and is often used in follow-up of conditions associated with bronchiectasis, such as chronic infections or interstitial lung diseases. Chest CT without IV contrast may be appropriate for assessing patients with known bronchiectasis and a change in clinical status to exclude pulmonary causes [40]. Chest CT without IV contrast can be used to quantify extent and severity of bronchiectasis with special software. A systematic review of 122 studies found 42 quantitative CT scoring methods in the research literature, including calculation of bronchial-arterial ratios, bronchial diameters, or bronchial surface area [43].


Tracheobronchial Disease

Tracheobronchial Disease. Severity of bronchiectasis at CT correlates with measures of airflow obstruction [40]. Although well-established guidelines on imaging follow-up of bronchiectasis are lacking, in practice, patients with diseases associated with bronchiectasis may be assessed with CT to help guide therapy and to provide prognostic information. Patients with NTMB may be followed with chest CT to assess response to therapy or worsening of disease. A study of 210 patients with NTMB found that higher CT severity scores (a combined assessment of nodules, bronchiectasis, cavities, and consolidation) were associated with higher organism sputum counts and worse prognosis [49]; higher sputum organism count was also associated with CT findings of small nodules, consolidation, bronchiectasis, and pleural thickening in another study of 50 patients with NTMB [50]. In a study of 488 patients with NTMB, patients with predominantly fibrocavitary disease were more likely to experience clinical deterioration than those with primarily noncavitary manifestations [51]. In a study of 40 patients with NTMB lung disease not undergoing antimycobacterial treatment, 39 (98%) showed worsening on chest CT findings over the course of Tracheobronchial Disease several years [52], although another study of 475 patients with NTMB pulmonary disease showed improvement in CT scores with antibiotic treatment [53]. In a study of 67 patients with NTMB, more extensive total lung involvement and higher cavitary volume were independently associated with worse pulmonary function [54]. CT may be useful for follow-up of patients with bronchiectasis who may be at risk of developing NTMB.


Tracheobronchial Disease

Tracheobronchial Disease. A study of 221 patients with bronchiectasis found new-onset NTMB pulmonary disease in 31 (14%) patients, which was associated with worsening of bronchiectasis, bronchiolitis, and other nodules on CT [55], and another study of 84 patients showed that more severe bronchiectasis and presence of cavities were more likely in NTMB pulmonary disease than in asymptomatic colonization [42]. Some studies have also found an association of CT severity scores and likelihood of NTMB treatment failure [56]. CT Neck and Chest With IV Contrast There is no relevant literature to support the use of neck and chest CT with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Neck and Chest Without and With IV Contrast There is no relevant literature to support the use of neck and chest CT without and with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Neck and Chest Without IV Contrast There is no relevant literature to support the use of neck and chest CT without IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Neck With IV Contrast There is no relevant literature to support the use of neck CT with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Neck Without and With IV Contrast There is no relevant literature to support the use of neck CT without and with IV contrast in the evaluation of bronchiectasis complications or treatment response. CT Neck Without IV Contrast There is no relevant literature to support the use of neck CT without IV contrast in the evaluation of bronchiectasis complications or treatment response. CTA Chest With IV Contrast There is no relevant literature to support the use of chest CTA for assessment of other bronchiectasis complications or treatment response.


Thyroid Disease

Thyroid Disease.  Introduction/Background There are a wide variety of diseases that affect the thyroid gland and range from hyperplastic to neoplastic, autoimmune, or inflammatory. They can present with functional abnormality or a palpable structural change. Imaging has a key role in diagnosing and characterizing the thyroid finding for management. Imaging is also essential in the management of thyroid cancer. When biopsy reveals the diagnosis of thyroid cancer, imaging has several roles, depending on the type of cancer. Papillary and follicular carcinomas arise from the follicular epithelial cells are known as differentiated thyroid carcinomas (DTC), representing 84% and 11% of all thyroid malignancies, respectively [2]. DTC have an excellent prognosis, with a 10-year survival rate of 99% for papillary carcinoma and 95% for follicular type [2]. DTCs are treated primarily with surgery and may have radioiodine ablation depending on the stage of disease. Medullary thyroid carcinoma (MTC) arises from parafollicular cells and is more aggressive, with a survival rate of 82% at 10 years [2]. MTC is also treated with surgery. Anaplastic carcinoma is an aggressive undifferentiated tumor typically occurring in the elderly with a 10-year survival of 8% [9]. Treatment of anaplastic carcinoma does not significantly impact survival. Other malignancies, such as thyroid lymphoma, sarcoma, and metastases, are rare. Imaging is used in operative planning, routine tumor surveillance, and further evaluation of suspected recurrence. The American College of Radiology seeks and encourages collaboration with other organizations on the development of the ACR Appropriateness Criteria through society representation on expert panels. Participation by representatives from collaborating societies on the expert panel does not necessarily imply individual or society endorsement of the final document. *The views expressed in this manuscript are those of the author and do not reflect the official policy of the Department of Army/Navy/Air Force,


Thyroid Disease

Thyroid Disease. Department of Defense, or United States Government. Reprint requests to: publications@acr.org Thyroid Disease Special Imaging Considerations Use of iodinated intravenous (IV) contrast for CT helps to delineate invasive tumor and morphological abnormalities in small nodal metastases. In the past, there were concerns about iodinated contrast agents delaying subsequent whole-body scans or radioiodine ablation; however, this has now been shown to be unfounded. Recent studies show that water-soluble iodinated contrast agents are generally cleared within 4 to 8 weeks in most patients; therefore, post-thyroidectomy patients requiring radioiodine therapy can be scanned with radioactive iodine (RAI) within 1 month of the contrast-enhanced CT [11,12]. Discussion of Procedures by Variant Variant 1: Palpable thyroid nodule. Not goiter. Euthyroid. Initial imaging. Screening for thyroid cancer by palpation is not recommended by the U.S. Preventive Task Force [15]. However, if a patient presents with a palpable neck nodule, the goal of imaging is to determine if the palpable abnormality corresponds to a thyroid nodule and to characterize the nodule for malignancy risk. Thyroid function tests should be performed first. If the serum thyroid-stimulating hormone (TSH) is subnormal, then the patient has thyrotoxicosis (Variant 3). This variant refers to a palpable thyroid nodule in the setting of a euthyroid patient. US Thyroid US provides high-resolution imaging to show that the palpable abnormality is within the thyroid and is the best study to characterize the nodule for the risk of malignancy. Certain sonographic features are more prevalent in malignancies. The combination of these features and the nodule size guide the decision to biopsy under the ACR TI-RADS and other risk stratification criteria [8,16]. CT Neck There is no evidence that CT can differentiate between malignant and benign nodules unless there is gross invasion or metastatic disease [7].


Thyroid Disease

Thyroid Disease. There may be a role for this cross-sectional imaging modality if the nodule is part of a goiter that is suspected to extend substernally or there is a suspicion of invasive thyroid cancer. Dual- phase CT imaging with and without IV contrast does not provide any additional information. MRI Neck There is no evidence that MRI can differentiate between malignant and benign nodules unless there is gross invasion or metastatic disease. There may be a role for this cross-sectional imaging modality if the nodule is part of a goiter that is suspected to extend substernally or there is a suspicion of invasive thyroid cancer. CT is preferred since there is less respiratory motion artifact. FDG-PET/CT Whole Body There is no evidence to support the use of PET using the tracer fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG)/CT in the setting of palpable thyroid nodule. Radionuclide Uptake and Scan In euthyroid patients, radioisotope scanning is not helpful in determining malignancy and decision to biopsy. Although cold nodules are more likely to be malignant, the majority of nodules are cold, and the majority of cold nodules are benign, resulting in a low positive predictive value. Variant 2: Suspected goiter. Initial imaging. A goiter is suspected based on a diffuse palpable abnormality or obstructive symptoms, such as dyspnea, orthopnea, obstructive sleep apnea, dysphagia, and dysphonia. These symptoms are related to mass effect on the trachea or esophagus. Thyroid Disease The role of imaging is to confirm the diagnosis of goiter and document the size and extent of the goiter. If obstructive symptoms are present, imaging can quantify the degree of compression on the trachea. This information is valuable in deciding if surgery will improve obstructive symptoms and planning operative approach. US Thyroid US is the preferred first-line imaging modality for suspected goiter. It confirms that the neck mass is arising from the thyroid and characterizes the size and morphology of the goiter.


Thyroid Disease

Thyroid Disease. If the goiter is nodular, US can also evaluate for suspicious features in nodules (see Variant 1). CT Neck CT is superior to US for evaluating substernal extension and deep extension to the retropharyngeal space [17]. CT can also define the degree of tracheal compression more effectively than US. Performing a CT with iodinated contrast is not necessary for goiter evaluation unless there is concern for an infiltrative neoplasm. Dual-phase CT imaging with and without IV contrast does not provide any additional information. MRI Neck MRI is an alternative to CT for characterizing the goiter, but CT is preferred because there is less respiratory motion artifact. Performing an MRI with IV contrast is not necessary for goiter evaluation unless there is concern for an infiltrative neoplasm. FDG-PET/CT Whole Body FDG-PET/CT imaging is not recommended as the initial imaging for the evaluation of suspected goiter. Radionuclide Uptake and Scan Radionuclide uptake may have a role if the goiter is associated with thyrotoxicosis. The radionuclide uptake and scan confirms that the entire goiter consists of thyroid tissue. Iodine-123 (I-123) is preferred over iodine-131 (I- 131) because of its superior imaging quality [18]. In addition to confirming the entire goiter is made of thyroid tissue, in a multinodular goiter the scan should be compared to an US to identify hypofunctioning or isofunctioning nodules to be targeted for biopsy [16]. Variant 3: Thyrotoxicosis. Initial imaging. Thyrotoxicosis may present with symptoms of hyperthyroidism, such as heat intolerance, tachycardia, anxiety, and weight loss, or be subclinical and found as an incidental laboratory abnormality (low TSH). The most common causes of thyrotoxicosis are Graves disease, toxic adenoma, toxic multinodular goiter, and subacute thyroiditis. Rare causes include trophoblastic disease, thyroid hormone resistance, amiodarone-induced thyroiditis, iatrogenic thyrotoxicosis, factitious ingestion of thyroid hormone, and struma ovarii [19].


Thyroid Disease

Thyroid Disease. Graves disease is diagnosed by laboratory tests, including measurement of TSH receptor antibodies [20], but in ambiguous cases or where toxic adenoma or multinodular goiter is suspected [19], imaging with an iodine uptake and scan can help confirm the cause for thyrotoxicosis. Imaging also has a role in planning therapy with RAI. US Thyroid US is the best imaging study to evaluate thyroid morphology and can be a helpful adjunct study to a radioiodine uptake. When a radioactive uptake scan shows nodules from toxic multinodular goiter or toxic adenoma, US can confirm presence of nodules and also evaluate for suspicious features of malignancy (see Variant 1). US also provides thyroid dimensions for planning RAI treatment [19]. Doppler US may be an alternative to nuclear medicine for separating thyrotoxicosis that is due to an overactive thyroid, such as Graves disease and toxic adenoma, from thyrotoxicosis, which is due to destructive causes such as subacute or lymphocytic thyroiditis. On Doppler US, these two causes of thyrotoxicosis have increased and decreased thyroid blood flow, respectively [21,22]. Although one study found similar sensitivity and specificity for Doppler US (95% and 90%) and radionuclide uptake studies (90% and 100%) [23], a radionuclide uptake study is still preferred because it directly measures thyroid activity rather than inferring it based on blood flow [24]. Among rarer causes of thyrotoxicosis, US can also distinguish between the two types of amiodarone-induced thyrotoxicosis. Type I (iodine-induced hyperthyroidism) has an enlarged or nodular thyroid gland, whereas type II (destructive) has a normal or small diffuse goiter with decreased blood flow [24]. Other causes also have characteristic features. Postpartum destructive thyroiditis has decreased blood flow. Findings of acute thyroiditis Thyroid Disease on US are hypoechoic lesions in and near the thyroid, tissue destruction, and abscesses.