title: Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.
abstract: OBJECTIVE
  To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.
  
  
  METHODS
  IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.
  
  
  RESULTS
  Scores of "5" were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of "5" were more predictive than resident scores of "5" (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of "5" included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).
  
  
  CONCLUSIONS
  Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.
authors.affiliation: Department of Radiology, University of Michigan Health System, B2-A209P, Ann Arbor, MI, 48109, USA.
authors.forename: D I
authors.initials: DI
authors.lastname: Glazer
authors.forename: M S
authors.initials: MS
authors.lastname: Davenport
authors.forename: S
authors.initials: S
authors.lastname: Khalatbari
authors.forename: R H
authors.initials: RH
authors.lastname: Cohan
authors.forename: J H
authors.initials: JH
authors.lastname: Ellis
authors.forename: E M
authors.initials: EM
authors.lastname: Caoili
authors.forename: E B
authors.initials: EB
authors.lastname: Stein
authors.forename: J C
authors.initials: JC
authors.lastname: Childress
authors.forename: W R
authors.initials: WR
authors.lastname: Masch
authors.forename: J M
authors.initials: JM
authors.lastname: Brown
authors.forename: B J
authors.initials: BJ
authors.lastname: Mollard
authors.forename: J S
authors.initials: JS
authors.lastname: Montgomery
authors.forename: G S
authors.initials: GS
authors.lastname: Palapattu
authors.forename: I R
authors.initials: IR
authors.lastname: Francis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D011856:Radiographic Image Enhancement; D014057:Tomography, X-Ray Computed