Is breast MRI ever useful in a mammographic screening programme?

OBJECTIVE: To establish the diagnostic impact of breast magnetic resonance imaging (MRI), on the management of cases in our mammographic screening programme. METHODS AND MATERIALS: We analysed the cases examined from July 1997 to December 2000 during which time 44,000 population screening mammograms and 85 MRI studies were undertaken on women identified by computer overlap. The studies were reviewed to find the reason for the MRI study and its diagnostic impact. RESULTS: Of 83 studies analysed, 31 were for recurrence of tumour, 33 in newly diagnosed cancer, 22 to assess extent, 11 to monitor primary chemotherapy. In a small diagnostic subset of 19 cases MRI was used to find or characterize a lesion. The 11 cases in which MRI results caused a measurable beneficial change in management were from the query recurrence and diagnostic groups. In 52 cases from all groups, MR increased diagnostic confidence. In 11 cases MRI results were indeterminate, and in six of these stimulated more studies. CONCLUSION: MRI is an expensive investigation and its use must be justified. There is a limited, but valuable role for breast MRI in selected cases from screening assessment. Misinterpretation of enhancing lesions may generate additional procedures. Diagnostic impact was greatest for the detection of tumour recurrence.