title: MRI characterization of the dynamic effects of 5α-reductase inhibitors on prostate zonal volumes.
abstract: BACKGROUND
  Prior studies of volumetric effects of 5α-reductase inhibitors (5ARIs) on the prostate have used transrectal ultrasound which provides poor differentiation of prostatic zones. We utilized high-resolution prostate MRI to evaluate the true dynamic effects of 5ARI in men who underwent multiple MRIs.
  
  
  METHODS
  A retrospective study of patients who underwent serial 3.0 Tesla prostate MRI from 2007 to 2012 and were treated with 5ARI were studied. Nineteen patients who had a baseline MRI prior to 5ARI initiation and subsequent MRI follow up were selected. A randomly selected group of 40 patients who had not received any form of therapy was selected as the control cohort. Total prostate volume (TPV), transition zone volume (TZV), and peripheral zone volume (PZV) were calculated using 3D reconstructions and prostate segmentation from T2-weighted MRI. Changes in volumes were correlated with the duration of treatment using linear regression analysis.
  
  
  RESULTS
  Following over 2 years of treatment, 5ARI decreased TPV significantly (16.7%, p < 0.0001). There were similar decreases in TZV (7.5%, p < 0.001) and PZV (27.4%, p = 0.0002) from baseline. In the control group, TPV and TZV increased (p < 0.0001) while PZV remained stable. When adjusted for the natural growth of prostate zonal volume dynamics seen in the control cohort, approximately 60% of the reduction of the TPV from 5ARI resulted from changes in the TZV and 40% of the reduction from changes in the PZV.
  
  
  CONCLUSIONS
  3.0 Tesla MRI characterizations of the dynamic effects of 5ARI on prostate zonal volumes demonstrate significant decreases in TPV, TZV, and PZV. 5ARI blocks the natural growth of TZV as men age and decreases both TZV and PZV below their baselines. As imaging technology improves, prostate MRI allows for more accurate assessment of drug effects on dynamic prostate volumes.
authors: National Institutes of Health, Bethesda, Maryland, USA.
authors: Hong
authors: H
authors: Truong
authors: Jennifer
authors: J
authors: Logan
authors: Baris
authors: B
authors: Turkbey
authors: M Minhaj
authors: MM
authors: Siddiqui
authors: Soroush
authors: S
authors: Rais-Bahrami
authors: Anthony N
authors: AN
authors: Hoang
authors: Chad
authors: C
authors: Pusateri
authors: Brian
authors: B
authors: Shuch
authors: Annerleim
authors: A
authors: Walton-Diaz
authors: Srinivas
authors: S
authors: Vourganti
authors: Jeffrey
authors: J
authors: Nix
authors: Lambros
authors: L
authors: Stamatakis
authors: Colette
authors: C
authors: Harris
authors: Celene
authors: C
authors: Chua
authors: Peter L
authors: PL
authors: Choyke
authors: Bradford J
authors: BJ
authors: Wood
authors: Peter A
authors: PA
authors: Pinto
mesh_terms: D058891:5-alpha Reductase Inhibitors / Q000627:therapeutic use*; D000368:Aged; D001378:Azasteroids / Q000627:therapeutic use; D000068538:Dutasteride; D018120:Finasteride / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000187:drug effects; D011467:Prostate / Q000187:drug effects* / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000188:drug therapy* / Q000473:pathology; D012189:Retrospective Studies
chemical_list: D058891:5-alpha Reductase Inhibitors; D001378:Azasteroids; D018120:Finasteride; D000068538:Dutasteride