title: High-spatial-resolution 3-T breast MRI of nonmasslike enhancement lesions: an analysis of their features as significant predictors of malignancy.
abstract: OBJECTIVE
  The purpose of this study was to analyze the features of nonmasslike enhancement detected on 3-T MRI and to determine which of these features are significant predictors of malignancy.
  
  
  METHODS
  Retrospective review was performed of 124 consecutive patients with nonmasslike enhancement detected on 3-T MRI after biopsy or surgery. We described nonmasslike enhancement using the descriptors in the BI-RADS MRI lexicon. In addition to the BI-RADS descriptors, whether clustered ring enhancement was present and whether surrounding high signal intensity (SI) was present on T2-weighted imaging were assessed.
  
  
  RESULTS
  Cancer was identified in 85 lesions (69%). Of these lesions, ductal carcinoma in situ (DCIS) was found in 41 (48%) and invasive cancer in 44 (52%). The features found to be significant predictors of malignancy were segmental (p = 0.001), focal (p = 0.006), dendritic (p = 0.017), and clustered ring enhancement (p = 0.026) and surrounding high SI on T2-weighted imaging (p < 0.0001). The features found to be significant predictors of invasive cancer were dendritic enhancement (p < 0.0001) and surrounding high SI on T2-weighted imaging (p < 0.0001). There were no significant predictive features for DCIS. Homogeneous enhancement was found to be a significant predictor of benignancy (p = 0.001). Kinetic patterns were not significant predictors of malignancy. Nonmasslike enhancement of 1 cm or larger was more often malignant than lesions smaller than 1 cm (p < 0.0001). In multivariate analysis, a lesion size of 1 cm or larger was found to be the only significant predictor of malignancy for nonmasslike enhancement.
  
  
  CONCLUSIONS
  Segmental, focal, dendritic, and clustered ring enhancement; surrounding high SI on T2-weighted imaging; and a lesion size of 1 cm or larger can act as predictors of malignancy for nonmasslike enhancement detected on 3-T MRI, but kinetic characteristics cannot.
authors.affiliation: Breast Imaging and Breast Intervention Section, Shizuoka Cancer Center Hospital, Japan. t.uematsu@scchr.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Uematsu
authors.forename: Masako
authors.initials: M
authors.lastname: Kasami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D002278:Carcinoma in Situ / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011237:Predictive Value of Tests; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media