Pure ductal carcinoma in situ: Kinetic and morphologic MR characteristics compared with mammographic appearance and nuclear grade

Purpose: To retrospectively compare the kinetic and morphologic characteristics of pure ductal carcinoma in situ (DCIS) lesions depicted on dynamic contrast material-enhanced magnetic resonance (MR) images with the nuclear grade and conventional mammographic appearance of these lesions. Materials and Methods: This HIPAA-compliant retrospective study was institutional review board approved, and informed patient consent was waived. Seventy-eight patients with 79 histologically proved pure DCIS lesions were selected. There were 17 low-nuclear-grade, 26 intermediate-nuclear-grade, 30 high-nuclear-grade, and six unclassified lesions. Sixty-five lesions were classified as fine pleomorphic, fine linear, or fine linear-branching calcifications (n = 31); amorphous or indistinct calcifications (n = 18); noncalcified mass (n = 10); or occult (n = 6) at conventional (x-ray) mammography. One experienced radiologist analyzed lesion morphology and kinetic curve shape according to the Breast Imaging Reporting and Data System lexicon. Initial enhancement percentage, time to peak enhancement (T-peak), and signal enhancement ratio (a measure of washout) were calculated for each lesion. Results: Of the 79 pure DCIS lesions, 20 (25%) exhibited enhancement plateau curves and 35 (44%) exhibited washout curves. The lesions with a masslike appearance on mammograms exhibited more suspicious kinetic characteristics (mean T-peak similar to 2 minutes) than did the lesions with amorphous or indistinct calcifications (mean T-peak = 4.4 minutes). There was no significant difference in enhancement kinetic properties across the nuclear grades. Lesion morphology was predominantly nonmass, with clumped or heterogeneous enhancement in a segmental or linear distribution. Conclusion: The pure DCIS lesions exhibited washout, plateau, and persistent enhancement curves. Enhancement kinetic characteristics varied with mammographic appearance but not with nuclear grade.