(Wednesday, 7/17/2019) 10:00 AM - 10:30 AM
Room: Exhibit Hall | Forum 8
Purpose: A digital MRI phantom and a general MRI acquisition simulation procedure were developed to simulate MRI data acquired from various sequences for objects subject to respiratory and cardiac motion. A binning based 4D MRI reconstruction method was developed to support image reconstruction.
Methods: A chest-abdomen digital phantom was developed from an analytical Shepp–Logan MRI phantom. Four organs (lung, heart, liver and stomach) were included. The cardiac motion was simplified as expansion and contraction of the heart, and respiratory motions were simplified as vertical motion of lung, heart, liver and stomach and expansion and contraction of lungs. T1w MRI k-space raw-data were simulated based on clinical parameters of each organs. A 4D reconstruction method was developed to reconstruct MRI at different stages of respiratory and cardiac motion after two sets of bins of respiratory and cardiac motion were applied to the simulated data respectively.
Results: This study presents an example of the simulated MRI data from a T1 sequence and the reconstruction results of 5 stages of respiratory motion and 3 stages of cardiac motion. The digital phantom offers a noise and artifact-free ground truth and can simulate respiratory and cardiac motion of organs simultaneously. Different k-space sampling such as Cartesian or Radial sampling can be simulated in data acquisition. Other reconstruction methods such as compressed sensing methods can also be used to improve reconstruction results.
Conclusion: We have created an analytical body phantom and digital procedures to simulate MRI acquisition under respiratory and cardiac motion. Results of this study will be very useful to support development of motion-compensation reconstruction methods to support 4D and 5D MRI for MRI guided radiation therapy and cardiac radiosurgery procedures.
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