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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) approximately 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.


SUPPLEMENTAL MATERIAL
http://radiology.rsnajnls.org/cgi/content/full/245/3/684/DC1.