Torsional Heart Motion in Cone-beam Computed Tomography Reconstruction

We study the effects of cardiac twist on phaseresolved cardiac C-arm cone-beam computed tomography reconstruction. First, a numeric, dynamic cardiac phantom is extended with an analytic model describing the heart’s twisting motion. Then, phase-resolved reconstructions are calculated using two methods based on ECG-gating and interpolation of the original motion field, respectively. We assessed overall reconstruction quality using the correlation of voxel intensities and found it largely unaffected by cardiac twist. We then confined the evaluation to the coronary arteries using the area under precision-recall curves. Decreasing performance at larger twist angles was observed with both methods at both fast and quiet heart phases. The results indicated that limited angle problems may occur for large twist angles in interventional settings, leading to degraded image quality. However, degradations were subtle and should not affect most practical cases.