Sixteen studies, with a total of 878 participants (range seven to 213), were included in the review. The most common methodological issues were possible differential verification bias (eight studies) and lack of blinding in interpretation of the index test and reference standard (six studies). Eleven studies did not report the time interval between the index test and reference standard.
The pooled estimate of sensitivity was 76% (95% CI 70 to 82) and the pooled estimate of specificity was 86% (95% CI 73 to 93). There was significant between study heterogeneity in both estimates; sensitivity estimates ranged from 33 to 100% and specificity estimates ranged from 40 to 100%.
Meta-regression analysis indicated that a lack of clearly reported selection criteria was associated with higher estimates of sensitivity and differential and partial verification biases were associated with higher estimates of specificity. The results of subgroup analyses were also presented; the diffusion weighted imaging subgroup had the highest sensitivity, 86% (95% CI 78 to 92).
Comparisons of MRI with positron emission tomography (seven studies), computed tomography (ten studies) and ultrasound (seven studies), showed no significant difference in diagnostic performance between MRI and other imaging modalities.
No evidence of publication bias was found.