title: Morphometric analysis of prostate zonal anatomy using magnetic resonance imaging: impact on age-related changes in patients in Japan and the USA.
abstract: To evaluate the impact of morphometric magnetic resonance imaging (MRI) analysis of the prostate zonal anatomy on aging, prostatic hypertrophy and lower urinary tract symptoms in patients from Japan and the USA.
  
  
  
  A retrospective analysis of 307 men, including 156 men from Japan and 151 from the USA, who consecutively underwent 3-Tesla MRI and International Prostate Symptom Score (IPSS) assessment because of elevated PSA levels. Using Synapse-Vincent (Fujifilm), the prostatic zones were segmented in each axial step-section of the T2-weighted MRI to reconstruct a three-dimensional model of the prostate, which was used to calculate: zonal volumes (whole-gland prostate, transition zone and peripheral zone volumes); the presumed circle area ratio (PCAR); and PZ thickness. Bivariate associations were quantified using Spearman's rank correlation coefficients.
  
  
  
  The USA subgroup had a greater prostate volume (49 vs 42 mL; P = 0.003) and TZ volume (26 vs 20 mL; P < 0.001) than the Japan subgroup, with no difference in PZ volume (19 vs 20 mL; P = 0.2). There was no age-related increase in PZ volume in either of the subgroups or in the entire cohort (P = 0.9, P = 0.2, P = 0.3, respectively). PZ thickness had a significant negative correlation with PCAR (P < 0.001) and TZ volume (P < 0.001). The greater the increase in the TZ volume with the increase in PCAR, which probably correlates with obstructive pressure, the thinner the PZ became. PCAR had a significant positive correlation with IPSS (P = 0.003) and obstructive symptoms (P = 0.007), while PZ thickness had a significant negative correlation (P = 0.018).
  
  
  
  No age-related increases and no differences between the Japanese and the US subgroups were found with regard to PZ volume. The more TZ volume increased, the higher the obstructive pressure and the thinner the PZ became; these changes were associated with increased obstructive symptoms. MRI analysis of prostate zonal anatomy enhanced our understanding of age-related changes in morphology and urinary symptoms.
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.|Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Matsugasumi
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Fujihara
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Ushijima
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Kanazawa
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Shiraishi
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Hongo
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kamoi
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Okihara
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Andre Luis
authors.initials: AL
authors.lastname: de Castro Abreu
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.|Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Oishi
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Shin
authors.affiliation: Department of Radiology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Palmer
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Inderbir S
authors.initials: IS
authors.lastname: Gill
authors.affiliation: Institute of Urology, University of Southern California, Los Angeles, CA, USA.|Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ukimura
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015331:Cohort Studies; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000000981:diagnostic imaging* / Q000473:pathology; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D014481:United States
chemical_list: D017430:Prostate-Specific Antigen
keywords: 
  MRI
  ; aging; anatomy; benign prostatic hyperplasia; morphology; prostate