Vascular CT

CTA

• Can be used to image arterial tree from aorta to pedal vessels
• Accurate down to tibial arteries; however, tedious to distinguish calcium and contrast at this level. Overestimation of the severity of a calcified stenosis is common.
• CTA is excellent for carotids, giving better anatomic reference than USS and not impeded by plaque presence.

Imaging kidney vasculature

• CTA and MRA are comparable in sensitivity for detection of proximal RAS. CTA is better for more distal disease, as MRA is affected by breathing artefact.
• MRA does allow contrast to be avoided, but gadolinium can also cause fibrosis in renal failure

Venous disease

• CT is better for central thrombosis (PE, mesenteric venous thrombosis) but USS better for peripheral veins

Vascular malformations

• CTA is only useful in high-flow malformations
• USS/MRI good for low-flow malformations

Shaded surface display (SSD)

• Density of vascular contrast, calcium and bone frequently overlap
• This means that calcifications are usually included as part of the contrast-enhanced vessel lumen
• SSDs show the exterior of the structure as opaque and shaded to provide an appreciation of depth

Maximum intensity projection (MIPs)

• Only the structure with maximum intensity is projected
• Plaque is displayed prominently