The value of magnetic resonance imaging in diagnosis and size assessment of in situ and small invasive breast carcinoma.

Background: The value of magnetic resonance imaging (MRI) in diagnosis and size assessment of ductal carcinoma-in-situ (DCIS) and DCIS with small (<10 mm) invasive carcinoma was evaluated.

Methods: Fifty-four patients with DCIS and 12 patients with DCIS and small invasive carcinoma were included. Mammographic (N = 64) and MRI (N = 22) images were retrospectively reviewed. Correlation coefficients were calculated to assess differences in size between imaging and histopathologic examination.

Results: Mammographic rate of detection for DCIS was 48/52 (92%) and for DCIS with small invasive carcinoma, 10/12 (83%). MRI revealed 1 false negative case and the rate of detection for DCIS was 16/17 (94%). Correlation of mammographic size with histopathologic size was r = .44 (P < .01) and r = 0.49 (P = .03) for MRI. Mammography underestimated lesion size by 5 mm or more in 47%, whereas with MRI size was adequately assessed in 43% and overestimated in 38%.

Conclusions: DCIS can be visualised on MRI with high sensitivity, although tumor size can be overestimated.