Robot-Assisted Deep Venous Thrombosis Ultrasound Examination using
  Virtual Fixture
Dianye Huang Chenguang Yang Mingchuan Zhou Angelos Karlas Nassir Navab Zhongliang Jiang
Deep Venous Thrombosis (DVT) is a common vascular disease with blood clots
inside deep veins, which may block blood flow or even cause a life-threatening
pulmonary embolism. A typical exam for DVT using ultrasound (US) imaging is by
pressing the target vein until its lumen is fully compressed. However, the
compression exam is highly operator-dependent. To alleviate intra- and
inter-variations, we present a robotic US system with a novel hybrid force
motion control scheme ensuring position and force tracking accuracy, and soft
landing of the probe onto the target surface. In addition, a path-based virtual
fixture is proposed to realize easy human-robot interaction for repeat
compression operation at the lesion location. To ensure the biometric
measurements obtained in different examinations are comparable, the 6D scanning
path is determined in a coarse-to-fine manner using both an external RGBD
camera and US images. The RGBD camera is first used to extract a rough scanning
path on the object. Then, the segmented vascular lumen from US images are used
to optimize the scanning path to ensure the visibility of the target object. To
generate a continuous scan path for developing virtual fixtures, an arc-length
based path fitting model considering both position and orientation is proposed.
Finally, the whole system is evaluated on a human-like arm phantom with an
uneven surface.