title: Application of MR mammography beyond local staging: is there a potential to accurately assess axillary lymph nodes? evaluation of an extended protocol in an initial prospective study.
abstract: OBJECTIVE
  The purpose of our study was to clinically test an extended MR mammography (MRM) protocol for combined local staging (T-staging) and locoregional staging (N-staging) of breast cancer within one single examination using a dedicated whole-body scanner.
  
  
  METHODS
  Fifty-six consecutive primary breast cancer patients without prior treatment underwent MRM and surgicopathological N-staging. The MRM protocol (10 minutes; axial T1-weighted gradient-recalled echo; dynamic contrast-enhanced; T2-weighted; turbo spin-echo) was extended to evaluate axillary lymph nodes (90 seconds; coronal T2-weighted HASTE; T1-weighted volumetric breath-hold examination; field of view, both axillae, supraclavicular nodes, and cervical nodes). A dedicated whole-body scanner was used. First, two experienced radiologists independently rated the presence of lymph node metastasis (present or absent, weighted kappa). Second, predefined descriptors were applied by both readers to differentiate lymph node status. These were statistically analyzed using univariate chi-square statistics, sensitivity and specificity, positive likelihood ratio, diagnostic odds ratio (OR), and multivariate statistics (binary logistic-regression, receiver operating characteristics, and chi-squared automatic interaction detection [CHAID] tree).
  
  
  RESULTS
  Most significant predictors (p < 0.001) of present metastasis were "irregular margin" (diagnostic OR, 14.0), "inhomogeneous cortex" (diagnostic OR, 8.4), "perifocal edema" (positive likelihood ratio, 100) and "asymmetry" (diagnostic OR, 19.5). CHAID tree identified "asymmetry" and "irregular margin" as significant predictors (adjusted-p < 0.05) for present metastasis (PPV: 100%), whereas absence of "asymmetry" and "homogeneous internal structure" were highly predictive of absent metastasis (negative predictive value, 94.3%). Combination of significant descriptors using binary logistic regression revealed an area under the receiver operating characteristic curve of 0.93 (p < 0.001). Interrater agreement was "almost-perfect" (κ = 0.95).
  
  
  CONCLUSIONS
  Combined T-staging and locoregional staging (N-staging) was possible within one imaging session using the proposed protocol. Despite a minimal increase in examination time, high diagnostic accuracy and excellent interrater reliability were achieved.
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University Jena, Germany. pascal.baltzer@med.uni-jena.de
authors.forename: Pascal A T
authors.initials: PA
authors.lastname: Baltzer
authors.forename: Matthias
authors.initials: M
authors.lastname: Dietzel
authors.forename: Hartmut P
authors.initials: HP
authors.lastname: Burmeister
authors.forename: Ramy
authors.initials: R
authors.lastname: Zoubi
authors.forename: Mieczyslaw
authors.initials: M
authors.lastname: Gajda
authors.forename: Oumar
authors.initials: O
authors.lastname: Camara
authors.forename: Werner A
authors.initials: WA
authors.lastname: Kaiser
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D002985:Clinical Protocols; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008327:Mammography / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results