title: The value of ADC, T2 signal intensity, and a combination of both parameters to assess Gleason score and primary Gleason grades in patients with known prostate cancer.
abstract: BACKGROUND
  The ability to non-invasively analyze tumor aggressiveness is an important predictor for individual treatment stratification and patient outcome in prostate cancer (PCA).
  
  
  OBJECTIVE
  To evaluate: (i) whether apparent diffusion coefficient (ADC), the T2 signal intensity (SI), and a combination of both parameters allow for an improved discrimination of Gleason Score (GS) ≥7 (intermediate and high risk) and GS <7 (low risk) in PCA; and (ii) whether ADC may distinguish between 3 + 4 and 4 + 3 PCA (primary Gleason grades [pGG]).
  
  
  METHODS
  Prostatectomy specimens of 66 patients (mean age, 63 ± 5.6 years; 104 PCA foci) with a preceding multiparametric 1.5 T endorectal coil magnetic resonance imaging (MRI) were included. ADC (b values = 0, 100, 400, 800 s/mm(2)), standardized T2 (T2s), and the ADC/T2s ratio were tested for correlation with GS applying multivariate analysis. ADC cutoff values were calculated for prediction of GS and pGG, and logarithm of the odds (LOGIT) was used to express the probability for GS and pGG. Diagnostic accuracy was assessed by ROC analysis.
  
  
  RESULTS
  We found an almost linear negative relationship of ADC for GS ≥7 (P = 0.002). The effect of ADC for GS ≥7 (adjusted odds ratio = 0.995) was almost identical for peripheral and transition zone PCA (P = 0.013 and P < 0.001, respectively). ADC showed an AUC of 78.9% for discrimination between GS <7 and GS ≥7. An ADC cutoff of <1.005 × 10(-3 )mm(2)/s indicated a GS ≥7 (90.5% sensitivity, 62.5% specificity). Within the group of GS = 7 PCA, an ADC > 0.762 × 10(-3 )mm(2)/s indicated a pGG of 3 (AUC = 69.6%).
  
  
  CONCLUSIONS
  T2s and the ADC/T2s ratio do not provide additional information regarding prediction of GS. ADC values have a good discriminatory power to distinguish tumors with GS ≥7 from GS <7 and to predict pGG in GS = 7 PCA.
authors.affiliation: Department of Radiology, Universitätsklinikum Würzburg, Germany Department of Radiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Nowak
authors.affiliation: Institute for Clinical Epidemiology and Biometry, Universität Würzburg, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Malzahn
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Alexander D J
authors.initials: AD
authors.lastname: Baur
authors.affiliation: Institute for Pathology, Vivantes Klinikum am Urban Dieffenbachstrasse, Berlin, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Reichelt
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Germany Department of Radiology, Universitätsklinikum Jena, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Franiel
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Germany tahir.durmus@charite.de.
authors.forename: Tahir
authors.initials: T
authors.lastname: Durmus
mesh_terms: D000368:Aged; D006801:Humans; D061705:Image-Guided Biopsy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies
keywords: Gleason score; Prostate; cancer; diffusion-weighted imaging (DWI); magnetic resonance imaging (MRI)