title: Lesion type and reader experience affect the diagnostic accuracy of breast MRI: a multiple reader ROC study.
abstract: OBJECTIVE
  To evaluate the influence of lesion type (mass versus non-mass) and reader experience on the diagnostic performance of breast MRI (BMRI) in a non-screening setting.
  
  
  METHODS
  Consecutive patients (mean age, 55 ± 12 years) with breast lesions that were verified by biopsy or surgery, and who had had BMRI as part of their diagnostic workup, were eligible for this retrospective single-center study. Cancers diagnosed by biopsy before BMRI were excluded to eliminate biological and interpretation bias due to biopsy or chemotherapy effects (n=103). Six blinded readers (experience level, high (HE, n=2); intermediate (IE, n=2); and low (LE, n=2)) evaluated all examinations and assigned independent MRI BI-RADS ratings. Lesion type (mass, non-mass, focal) was noted. Receiver operating characteristics (ROC) and logistic regression analysis was performed to compare diagnostic accuracies.
  
  
  RESULTS
  There were 259 histologically verified lesions (123 malignant, 136 benign) investigated. There were 169 mass (103 malignant, 66 benign) and 48 non-mass lesions (19 malignant, 29 benign). Another 42 lesions that met the inclusion criteria were biopsied due to conventional findings (i.e., microcalcifications, architectural distortions), but did not enhance on MRI (41 benign, one DCIS). ROC analysis revealed a total area under the curve (AUC) between 0.834 (LE) and 0.935 (HI). Logistic regression identified a significant effect of non-mass lesions (P<0.0001) and reader experience (P=0.005) on diagnostic performance.
  
  
  CONCLUSIONS
  Non-mass lesion type and low reader experience negatively affect the diagnostic performance of breast MRI in a non-screening setting.
authors.affiliation: Department of Biomedical Imaging and Imge-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria. Electronic address: patbaltzer@gmail.com.
authors.forename: Pascal A T
authors.initials: PAT
authors.lastname: Baltzer
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Jena, Erlanger Allee 101, 07740 Jena, Germany.
authors.forename: Werner Alois
authors.initials: WA
authors.lastname: Kaiser
authors.affiliation: Department of Neuroradiology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany. Electronic address: dietzelmatthias2@hotmail.com.
authors.forename: Matthias
authors.initials: M
authors.lastname: Dietzel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D002114:Calcinosis / Q000000981:diagnostic imaging; D002983:Clinical Competence / Q000706:statistics & numerical data*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011859:Radiography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: BI-RADS; Breast MRI; Neoplasms; Non-mass; Reader experience; Sensitivity and specificity