title: High-spatial-resolution MRI of non-masslike breast lesions: interpretation model based on BI-RADS MRI descriptors.
abstract: OBJECTIVE
  The purpose of this study was to assess an interpretation model based on BI-RADS MRI descriptors and high-spatial-resolution MR images in lesions showing non-masslike enhancement.
  
  
  METHODS
  Retrospective review was performed of 30 consecutive lesions showing non-masslike enhancement. MRI was performed on a 1.5-T scanner using the volumetric interpolated breath-hold examination sequence. The distribution patterns were classified into three categories: single quadrant/solitary lesion (linear), single quadrant/grouped lesion (focal, regional, segmental), and multiquadrant lesion (multiple regions, diffuse). The presence of a ductal pattern was assessed in the enhancing lesions after the tumor distribution had been decided. In addition to the BI-RADS MRI descriptors, the presence of clustered ring enhancement was also assessed in heterogeneous enhancing lesions.
  
  
  RESULTS
  The most frequent morphologic finding among the benign lesions was a linear pattern (50%) followed by homogeneous internal enhancement (42%), whereas a segmental pattern (56%) (p = 0.003), heterogeneous internal enhancement (44%), and clustered ring enhancement (44%) (p = 0.01) were the most frequent findings in malignant lesions. The features with the highest positive predictive value for carcinoma were a segmental distribution (100%), a clustered ring enhancement (100%), and a clumped internal architecture (88%). Using this interpretation model, the positive predictive value for carcinoma was 94%.
  
  
  CONCLUSIONS
  A combination of BI-RADS MRI descriptors and clustered ring enhancement criteria is useful for the differential diagnosis of lesions showing non-masslike enhancement.
authors.affiliation: Present address: Division of Diagnostic Imaging, Breast Center, Kameda Medical Center, 929 Higashi-cho, Kamogawa, Chiba, Japan 296-8602. e-tozaki@keh.biglobe.ne.jp
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tozaki
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Fukuda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000145:classification / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D012189:Retrospective Studies