Case 2: Contrast-enhanced magnetic resonance angiography (MRA) for arterial stenosis disease
In this case, we use meta-analysis data from the study of Menke and Larsen24 summarizing evidence about how well MRA detects arterial stenosis. A total of 32 studies were included in the analysis.
Figure 4 depicts the meta-analytic summary plots. It includes the summary ROC curve, individual study estimate, and summary point estimate of the “traditional” measures of performance of MRA in diagnosis of arterial stenosis. As with figure 1, the interpretation of traditional statistics in terms of test performance is difficult. For example, an MRA test diagnosing arterial stenosis is 96% specific and 78% sensitive. The combination of these values is difficult to interpret and may lead to inappropriate assessment. In terms of MI however, the test reduces diagnostic uncertainty by 49%, which indicates a clearly useful test.
Figure 5, demonstrates the meta-analysis of MI, in which it is shown that the information content of MRA in diagnosis of arterial stenosis is 0.53 (CI: 0.48, 0.57).
Figure 6 depicts the RMI for reported by each study as well as the pool estimate, which is approximately 67% for pre-test probability of disease 25%. That is, the MRA reduces uncertainty related to arterial stenosis by 67%.