Imaging of Vertebral Artery Stenosis

A systematic review 1 including 13 studies with at least 929 subjects was abstracted in DARE. The studies assessed Duplex ultrasound (DUS, 5 studies), magnetic resonance angiography (MRA, 7 studies) and computed tomography angiography (CTA, 1 study) against a reference standard of intra-arterial angiography for the diagnosis of vertebral artery stenosis.

• DUS without colour (3 studies): pooled sensitivity 70.2% (95% CI 56.6 to 81.6), pooled specificity 93.4% (95% CI 89.2 to 96.3) for diagnosis of 50 to 99% stenosis vs. <50% stenosis or 100% occlusion.
• DUS using colour (2 studies): pooled sensitivity 70.2% (95% CI 54.2 to 83.3), pooled specificity 97.7% (95% CI 95.2 to 99.1) for diagnosis of 50 to 99% stenosis vs. <50% stenosis or 100% occlusion.
• MRA, non-contrast (2 studies): one study showed very high sensitivity and specificity (100% and 97.4%, respectively), whilst the other showed poor sensitivity and specificity (53.8% and 88%, respectively).
• MRA, contrast-enhanced: 4 of 5 studies assessed 50 to 99% stenosis. The pooled sensitivity was 93.9% (95% CI 79.8 to 99.3), the pooled specificity was 94.8% (95% CI 91.1 to 97.3).
• CTA (1 study) for diagnosis of 50 to 99% stenosis: a sensitivity of 100% (95% CI: 15.8 to 100) and a specificity of 95.2% (95% CI: 83.8 to 99.4).

Comment: The quality of evidence is downgraded by limitations in study quality and by indirectness (no direct comparisons of the different methods).

References

• Khan S, Cloud GC, Kerry S, Markus HS. Imaging of vertebral artery stenosis: a systematic review. J Neurol Neurosurg Psychiatry 2007 Nov;78(11):1218-25. [PubMed] [DARE]