FetalDiffusion: Pose-Controllable 3D Fetal MRI Synthesis with
  Conditional Diffusion Model
Molin Zhang Polina Golland Patricia Ellen Grant Elfar Adalsteinsson
The quality of fetal MRI is significantly affected by unpredictable and
substantial fetal motion, leading to the introduction of artifacts even when
fast acquisition sequences are employed. The development of 3D real-time fetal
pose estimation approaches on volumetric EPI fetal MRI opens up a promising
avenue for fetal motion monitoring and prediction. Challenges arise in fetal
pose estimation due to limited number of real scanned fetal MR training images,
hindering model generalization when the acquired fetal MRI lacks adequate pose.
  In this study, we introduce FetalDiffusion, a novel approach utilizing a
conditional diffusion model to generate 3D synthetic fetal MRI with
controllable pose. Additionally, an auxiliary pose-level loss is adopted to
enhance model performance. Our work demonstrates the success of this proposed
model by producing high-quality synthetic fetal MRI images with accurate and
recognizable fetal poses, comparing favorably with in-vivo real fetal MRI.
Furthermore, we show that the integration of synthetic fetal MR images enhances
the fetal pose estimation model's performance, particularly when the number of
available real scanned data is limited resulting in 15.4% increase in PCK and
50.2% reduced in mean error. All experiments are done on a single 32GB V100
GPU. Our method holds promise for improving real-time tracking models, thereby
addressing fetal motion issues more effectively.