Contrast-enhanced MR Angiography of Supraaortic Vessels: The Effect of Voxel Size on Image Quality

46-year-old man referred for an ischemic event in the posterior fossa. Frontal view from contrast-enhanced MR angiogram (4.6/1.8/1, voxel size = 0.95 × 0.76 × 0.82) shows accurate delineation of vertebrobasilar system (arrows), despite wrap-around artifacts (star) at lower part of imaging volume that slightly degrade image quality.

fig 2. 75-year-old man referred for a subclavian steal syndrome with occlusion of initial portion of left subclavian artery (short arrow) and stenosis at origin of right vertebral artery (long arrow). Oblique view from MR angiogram (4.6/1.8/1, voxel size = 0.95 × 0.76 × 0.82) shows a rapid fall-off of signal intensity at inferior part of imaging volume and a moderate enhancement of left brachiocephalic vein (star), which degrades image quality at level of aortic arch and at origin of great vessels.

fig 3. 65-year-old man with atherosclerotic disease. Frontal view from MR angiogram (4.6/1.8/1, voxel size = 0.95 × 0.76 × 0.82) shows accurate delineation of cervical arteries, despite a moderate enhancement of jugular veins (stars).

fig 4. 56-year-old man with left external carotid stenosis (long arrow) and severe short stenosis at the distal portion of the right vertebral artery (short arrow). Frontal view from MR angiogram (4.6/1.8/1, voxel size = 1.3 × 1.29 × 1.25) shows a fair delineation of artery outlines despite a slight blurring of arterial lumen.

fig 5. 43-year-old woman with occlusive dissection of left internal carotid artery (long arrow). MR angiogram (4.6/1.8/1, voxel size = 1.3 × 1.29 × 1.25) shows a poor delineation of proximal segment of vertebral arteries (short arrows).