title: Decision making for breast lesions initially detected at contrast-enhanced breast MRI.
abstract: OBJECTIVE
  The purpose of this study was to assess the clinical significance of breast lesions initially detected at contrast-enhanced breast MRI and to consider how to manage those lesions in accordance with the imaging findings and the indication for MRI.
  
  
  METHODS
  A retrospective study of 4260 consecutive breast MRI examinations was performed to identify MRI-detected enhancing lesions. In 4260 studies, 554 MRI-detected lesions were found in 417 patients, and 134 (24%) of the lesions were malignant. Pathologic confirmation was obtained for 319 (58%) lesions. Results of the subsequent imaging workup, biopsy, surgery, and imaging follow-up were reviewed.
  
  
  RESULTS
  The median size of the lesions was 89 mm (malignant, 15.45 mm; benign, 7.48 mm). Irregular shape, irregular or spiculated margins, and heterogeneous or rim enhancement were seen significantly more often in malignant mass lesions (p < 0.001). Malignant lesions were more likely to exhibit rapid enhancement (p < 0.001). Benign lesions were more likely to have persistent kinetics (p < 0.001). There was a statistically significant difference (p < 0.001) between malignant (58/87, 67%) and benign lesions (128/287, 45%) with respect to sonographic detection at second-look ultrasound examinations. Malignant lesions were most often detected in patients with metastatic axillary lymph nodes with an unknown primary tumor (8/8, 100%), followed by patients with positive or close margins in recent breast cancer surgery (45/76, 59%), and patients with newly diagnosed breast cancer (44/115, 38%).
  
  
  CONCLUSIONS
  Management of MRI-detected lesions should be based on both MRI findings and the patient's indication for MRI.
authors.affiliation: 1 Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL 60637.
authors.forename: Ken
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: David
authors.initials: D
authors.lastname: Schacht
authors.forename: Charlene A
authors.initials: CA
authors.lastname: Sennett
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Newstead
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imaizumi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Irie
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003287:Contrast Media; D003657:Decision Making; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D016217:Ultrasonography, Mammary
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA