Sixty-two studies of 85 separate study populations were included: 21 series on MRA and 64 series on DUS. Further details of the study designs were not provided
Diagnosis of 70 to 99% versus less than 70% stenosis.
The diagnostic accuracy of the two tests were similar for severe stenosis: 4.1 (95% confidence interval, CI: 3.5, 4.8) for MRA and 4.0 (95% CI: 3.5, 4.5) for DUS. The data on sensitivity and specificity indicated better discriminatory power for MRA: the pooled sensitivity was 95% (95% CI: 92, 97) for MRA and 86% (95% CI: 84, 89) for DUS; the pooled specificities were 90% (95% CI: 86, 93) and 87% (95% CI: 84, 90), respectively.
When possible confounding variables were taken into consideration in the regression analysis, MRA was significantly better than DUS at discriminating 70 to 99% stenosis than less than 70% stenosis: the regression coefficient was 1.6 (95% CI: 0.37, 2.77, P=0.01). The sensitivity analysis showed that no individual study unduly influenced the results.
Diagnosis of less than 100% versus 100% stenosis.
The diagnostic accuracy of the two tests for occlusion was similar for distinguishing occlusion from severe stenosis: 6.5 (95% CI: 5.7, 7.4) for MRA and 6.5 (95% CI: 5.9, 7.0) for DUS. The pooled sensitivity was 98% (95% CI: 94, 100) for MRA and 96% (95% CI: 94, 98) for DUS; the pooled specificities of both MRA and DUS were 100% (95% CI: 99, 100).
When possible confounding variables were taken into consideration in the regression analysis, there was no difference between MRA and DUS in diagnostic performance: the regression coefficient was 0.73 (95% CI: -2.06, 3.51, P=0.51). The sensitivity analysis showed that no individual study unduly influenced the results.