Fig. 5.

Unsatisfactory registration during an iliac artery revascularization procedure. Panel A shows the misregistration of a contrast-enhanced MR angiogram with X-ray during XFM. Multiple fiducial markers are positioned on the abdominal skin. Panel B shows another patient with MR-derived arterial adventitial contours overlaid during recanalization of occlusive iliac in-stent restenosis. Both presumably reflect error introduced by nonrigid deformation and respiratory motion of the fiducial markers.