MR-IMAGING OF DUCTAL CARCINOMA IN-SITU

PURPOSE: To investigate the ability of magnetic resonance (MR) imaging to depict ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: Bet ween January 1992 and April 1996, 330 women underwent MR imaging befor e excisional biopsy. Of these, 101 women had carcinoma, 19 of whom had DCIS. The MR imaging findings in the 19 women were reviewed. RESULTS: Thirteen of 19 patients had pure DCIS. The mean lesion diameter was 1 0 mm (range, 2-22 mm). MR imaging enabled identification of DCIS in 10 (77%) of the 13 cases as ductal enhancement (n = 6), regional enhance ment (n = 3), or a peripherally enhancing mass (n = 1). The three lesi ons not identified had a mean diameter of 3.7 mm. Six of 19 patients h ad both DCIS and an invasive cancer. In four of these patients, DCIS w as identified only at MR imaging (mean diameter, 3 mm). In two of six patients, DCIS was not identified at MR imaging.CONCLUSION: MR imaging can depict mammographically visible and occult foci of DCIS. Some sma ll foci of DCIS detected at mammography and histologic examination, ho wever, may be occult at MR imaging.