title: Significance of Additional Non-Mass Enhancement in Patients with Breast Cancer on Preoperative 3T Dynamic Contrast Enhanced MRI of the Breast.
abstract: BACKGROUND
  In preoperative assessment of breast cancer, MRI has been shown to identify more additional breast lesions than are detectable using conventional imaging techniques. The characterization of additional lesions is more important than detection for optimal surgical treatment. Additional breast lesions can be included in focus, mass, and non-mass enhancement (NME) on MRI. According to the fifth edition of the breast imaging reporting and data system (BI-RADS®), which includes several changes in the NME descriptors, few studies to date have evaluated NME in preoperative assessment of breast cancer.
  
  
  OBJECTIVE
  We investigated the diagnostic accuracy of BI-RADS descriptors in predicting malignancy for additional NME lesions detected on preoperative 3T dynamic contrast enhanced MRI (DCE-MRI) in patients with newly diagnosed breast cancer.
  
  
  METHODS
  Between January 2008 and December 2012, 88 patients were enrolled in our study, all with NME lesions other than the index cancer on preoperative 3T DCE-MRI and all with accompanying histopathologic examination. The MRI findings were analyzed according to the BI-RADS MRI lexicon. We evaluated the size, distribution, internal enhancement pattern, and location of NME lesions relative to the index cancer (i.e., same quadrant, different quadrant, or contralateral breast).
  
  
  RESULTS
  On histopathologic analysis of the 88 NME lesions, 73 (83%) were malignant and 15 (17%) were benign. Lesion size did not differ significantly between malignant and benign lesions (P = 0.410). Malignancy was more frequent in linear (P = 0.005) and segmental (P = 0.011) distributions, and benignancy was more frequent in focal (P = 0.004) and regional (P < 0.001) NME lesions. The highest positive predictive value (PPV) for malignancy occurred in segmental (96.8%), linear (95.1%), clustered ring (100%), and clumped (92.0%) enhancement. Asymmetry demonstrated a high positive predictive value of 85.9%. The frequency of malignancy was higher for NME lesions located in the same quadrant with the index cancer (P = 0.006), and benignancy was higher in the contralateral breast (P = 0.015). On multivariate analysis, linear (P = 0.001) and segmental (P = 0.005) distributions were significant predictors of malignancy.
  
  
  CONCLUSIONS
  The possibility of malignancy is strongly indicated when additional NME lesions show linear or segmental enhancement on preoperative 3T DCE-MRI in patients with recently diagnosed breast cancer.
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Yun Hee
authors.initials: YH
authors.lastname: Cho
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Kyu Ran
authors.initials: KR
authors.lastname: Cho
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Park
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Bo Kyoung
authors.initials: BK
authors.lastname: Seo
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Ok Hee
authors.initials: OH
authors.lastname: Woo
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Sung Bum
authors.initials: SB
authors.lastname: Cho
authors.affiliation: Department of Surgery, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Jeoung Won
authors.initials: JW
authors.lastname: Bae
keywords: Breast Neoplasms; Diagnosis; Magnetic Resonance Imaging; Non-Mass Enhancement; Preoperative Care