What are the accuracy rates of CTA and MRA for detecting carotid stenosis?
Using consensus interpretation criteria, carotid ultrasound has a sensitivity of 38.8%, specificity of 91.6%, and accuracy of 87.1% for 70%. With the use of a 70% cutoff value for carotid stenosis, CTA and digital subtraction angiography were in agreement in 78 of 81 vessels (95% CI, 90 99). A meta-analysis of studies performed in 2008 found the overall sensitivity of time-of-flight MRA for the detection of 70% to 99% internal carotid artery (ICA) stenoses to be 91.2% with a specificity of 88.3%, whereas the sensitivity of contrast-enhanced MRA was 94.6% with a specificity of 91.9%.49