title: Visualizing the prostate gland by MR imaging in young and old mice.
abstract: OBJECTIVE
  Prostate imaging requires optimization in young and old mouse models. We tested which MR sequences and field strengths best depict the prostate gland in young and old mice; and, whether prostate MR signal, size, and architecture change with age.
  
  
  METHODS
  Magnetic resonance imaging (MRI) of the prostate of young (2 months) and old (18 months) male nude mice (n = 6) was performed at 4.7 and 7 T and SCID mice (n = 6) at 7 T field strengths, using T1, fat suppressed T1, DWI, T2, fat suppressed T2, as well as T2-based- and proton density-based Dixon "water only" sequences. Images were ranked for best overall sequence for prostate visualization, prostate delineation, and quality of fat suppression. Prostate volume and signal characteristics were compared and histology was performed.
  
  
  RESULTS
  T2-based-Dixon "water only" images ranked best overall for prostate visualization and delineation as well as fat suppression (n = 6, P<0.001) at both 4.7 T and 7 T in nude and 7T in SCID mice. Evaluated in nude mice, T2-based Dixon "water only" had greater prostate CNR and lower fat SNR at 7 T than 4.7 T (P<0.001). Prostate volume was less in older than younger mice (n = 6, P<0.02 nude mice; n = 6, P<0.002 SCID mice). Prostate T2 FSE as well as proton density-based and T2-based-Dixon "water only" signal intensity was higher in younger than older mice (P<0.001 nude mice; P<0.01 SCID mice) both at 4.7 and 7 T. This corresponded to an increase in glandular hyperplasia in older mice by histology (P<0.01, n = 6).
  
  
  CONCLUSIONS
  T2-based Dixon "water only" images best depict the mouse prostate in young and old nude mice at 4.7 and 7 T. The mouse prostate decreases in size with age. The decrease in T2 and T2-based Dixon "water only" signal with age corresponds with glandular hyperplasia. Findings suggest age should be an important determinant when choosing models of prostate biology and disease.
authors.affiliation: Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America.
authors.forename: Murali
authors.initials: M
authors.lastname: Ravoori
authors.forename: Jyoti
authors.initials: J
authors.lastname: Duggal
authors.forename: Mihai
authors.initials: M
authors.lastname: Gagea
authors.forename: Lin
authors.initials: L
authors.lastname: Han
authors.forename: Sheela
authors.initials: S
authors.lastname: Singh
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Dustin K
authors.initials: DK
authors.lastname: Ragan
authors.forename: James A
authors.initials: JA
authors.lastname: Bankson
authors.forename: Jingfei
authors.initials: J
authors.lastname: Ma
authors.forename: Vikas
authors.initials: V
authors.lastname: Kundra
mesh_terms: D000367:Age Factors; D000818:Animals; D006651:Histocytochemistry; D050152:Intra-Abdominal Fat / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D009929:Organ Size; D011467:Prostate / Q000033:anatomy & histology*; D011470:Prostatic Hyperplasia / Q000175:diagnosis* / Q000473:pathology*