title: Three-phase dynamic breast magnetic resonance imaging with two-way subtraction.
abstract: OBJECTIVE
  This study was undertaken to introduce a new breast magnetic resonance (MR) imaging technique, 3-phase dynamic MR imaging with 2-way subtraction, and to examine the morphologic and kinetic features of malignant and benign breast lesions using this technique.
  
  
  METHODS
  In 99 breasts from 89 consecutive women with suspicious breast lesions (age range: 32-72 years, mean = 48.2 years), MR imaging was performed using a fat-saturated, sagittal, gradient-echo sequence in 3 phases (1 precontrast and 2 postcontrast scans). Two-way subtraction was performed: standard subtraction (early postcontrast minus precontrast scans) and reverse subtraction (early postcontrast minus late postcontrast scans). A radiologist interpreted all the images, described the breast lesions (using the Breast Imaging Reporting and Data System MR lexicon), and assessed the lesions prospectively as being benign or malignant. The lesions with at least 1 malignant feature were classified as malignant. The MR classifications were compared with the biopsy or follow-up results.
  
  
  RESULTS
  Sixty-five (65.7%) breast lesions were malignant, and 34 (34.3%) were benign. Forty-two (97.7%) of the 43 cases of microinvasive or invasive ductal cancer showed malignant morphologic features, and 38 (88.4%) showed washout kinetics. Eighteen (81.8%) of the 22 cases of ductal carcinoma in situ showed malignant morphologic features, and 11 (50.0%) showed washout kinetics. Twenty-nine (85.3%) of the 34 benign lesions showed neither malignant morphologic features nor washout kinetics. The sensitivity and specificity were 92.3% and 91.2% by morphologic analysis and 93.8% and 85.3% by the combined method (morphology plus kinetic analysis), respectively.
  
  
  CONCLUSIONS
  This study demonstrated that 3-phase dynamic breast MR imaging with 2-way subtraction and a maximum intensity projection (MIP) image is a simple and useful technique for identifying breast lesions. Although the addition of the kinetic criteria enhanced the sensitivity at the cost of specificity, radiologists can diagnose a malignant lesion showing non-mass-like enhancement more confidently using reverse subtraction imaging. Therefore, this study proposes 3-phase dynamic imaging with 2-way subtraction and an MIP image as one of the standard protocols of breast MR imaging.
authors.affiliation: Department of Diagnostic Radiology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.
authors.forename: Nami
authors.initials: N
authors.lastname: Choi
authors.forename: Boo-Kyung
authors.initials: BK
authors.lastname: Han
authors.forename: Yeon Hyeon
authors.initials: YH
authors.lastname: Choe
authors.forename: Hye Sung
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000379:methods; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA