Nineteen studies (n=2,610 participants) were included in the review. Ten studies were prospective, seven were retrospective and two studies did not report design. Seven studies reported consecutive enrolment of patients.
Prevalence of detection of additional foci in the ipsilateral breast ranged from 6% to 34% (median 16%, interquartile range 11% to 24%). The estimated SROC gave a diagnostic odds ratio of 189 (95% CI 59 to 601) and an area under the curve of 98%. When the five studies with an assumed false negative rate of zero were removed from the analysis, the diagnostic odds ratio was 88 (95% CI 30 to 259) and the area under the curve was 96%.There was a statistically significant inverse relationship between the incremental accuracy of MRI and the quality of the reference standard (p=0.016). Positive predictive value ranged from 0.19 to 1.0 with an overall estimate of 0.66 (95% CI 0.52 to 0.77).
Rate of conversion from wide local excision to mastectomy was 8.1% (95% CI 5.9 to 11.3) and from wide local excision to more extensive surgery was 11.3% (95% CI 6.8 to 18.3). Changes in management as a result of MRI false positives were 1.1% (95% CI 0.3 to 3.6) and 5.5% (95% CI 3.1 to 9.5).