title: Morphology evaluation of nonmass enhancement on breast MRI: Effect of a three-step interpretation model for readers' performances and biopsy recommendations.
abstract: OBJECTIVE
  To evaluate and compare the use of a newly introduced interpretation model for breast nonmass enhancement (NME, defined as an area of enhancement without a three-dimensional, space-occupying lesion) with the use of the standard interpretation method based on BI-RADS.
  
  
  METHODS
  Two expert and two less-experienced breast imaging radiologists performed reading sessions of 86 malignant and 64 benign NME lesions twice. First, radiologists characterized NME using BI-RADS descriptors and assessed the likelihood of malignancy and need for a biopsy. Second, the likelihood of malignancy and need for a biopsy were assessed with the use of the model, in which three-step characterization of morphological features were performed: (1) selection of distribution modifiers, (2) homogeneous vs. heterogeneous internal enhancement (IE) pattern, and (3) evaluation of presence of "clumped", "clustered ring enhancement (CRE)", and "branching" IE signs. Multireader-multicase receiver operating characteristic analysis was used to evaluate observers' performances. Univariate and multivariate logistic regression analyses were performed for morphology descriptors.
  
  
  RESULTS
  With use of the model, average Az of less-experienced radiologists (0.77-0.83; p=0.013) and average sensitivity of all radiologists (96.2-98.2%; p=0.007) improved significantly. NPV also improved but nonsignificantly (81.1-91.9%; p=0.055). Multivariate analyses of the second reading showed branching, clumped, and CRE signs to be significant predictors of malignancy in the results of 3, 2, and 2 readers, respectively.
  
  
  CONCLUSIONS
  The three-step interpretation model for NME has the potential to improve less-experienced radiologists' performances, making them comparable to expert breast imagers.
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan. Electronic address: akikoshima@gmail.com.
authors.forename: Akiko
authors.initials: A
authors.lastname: Shimauchi
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ota
authors.affiliation: Department of Radiology, Kameda Kyobashi Clinic, 3-1-1, Kyobashi, Chuo-ku 104-0031, Tokyo, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Machida
authors.affiliation: Department of Radiology, Kameda Kyobashi Clinic, 3-1-1, Kyobashi, Chuo-ku 104-0031, Tokyo, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Satani
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Mori
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba-ku, Sendai 980-8574, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Takase
authors.affiliation: Department of Radiology, Kameda Kyobashi Clinic, 3-1-1, Kyobashi, Chuo-ku 104-0031, Tokyo, Japan; Department of Radiology, Sagara Hospital Affiliated Breast Center, 3-28 Tenokuchi-cho, Kagoshima 892-0845, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tozaki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D011336:Probability; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Breast; Breast tumors; Cancer; Magnetic resonance imaging; Radiology