title: Quantification of mineralized bone response to prostate cancer by noninvasive in vivo microCT and non-destructive ex vivo microCT and DXA in a mouse model.
abstract: BACKGROUND
  To compare nondestructive in vivo and ex vivo micro-computed tomography (muCT) and ex vivo dual-energy-X-ray-absorptiometry (DXA) in characterizing mineralized cortical and trabecular bone response to prostate cancer involving the skeleton in a mouse model.
  
  
  RESULTS
  In vivo microCT was performed before and 10 weeks after implantation of human prostate cancer cells (MDA-PCa-2b) or vehicle into SCID mouse femora. After resection, femora were imaged by nondestructive ex vivo specimen microCT at three voxel sizes (31 micro, 16 micro, 8 micro) and DXA, and then sectioned for histomorphometric analysis of mineralized bone. Bone mineral density (BMD), trabecular parameters (number, TbN; separation, TbSp; thickness, TbTh) and mineralized bone volume/total bone volume (BV/TV) were compared and correlated among imaging methods and histomorphometry. Statistical tests were considered significant if P<0.05. Ten weeks post inoculation, diaphyseal BMD increased in the femur with tumor compared to the opposite femur by all modalities (p<0.005, n = 11). Diaphyseal BMD by in vivo microCT correlated with ex vivo 31 and 16 microm microCT and histomorphometry BV/TV (r = 0.91-0.94, P<0.001, n = 11). DXA BMD correlated less with bone histomorphometry (r = 0.73, P<0.001, n = 11) and DXA did not distinguish trabeculae from cortex. By in vivo and ex vivo microCT, trabecular BMD decreased (P<0.05, n = 11) as opposed to the cortex. Unlike BMD, trabecular morphologic parameters were threshold-dependent and when using "fixed-optimal-thresholds," all except TbTh demonstrated trabecular loss with tumor and correlated with histomorphometry (r = 0.73-0.90, P<0.05, n = 11).
  
  
  CONCLUSIONS
  Prostate cancer involving the skeleton can elicit a host bone response that differentially affects the cortex compared to trabeculae and that can be quantified noninvasively in vivo and nondestructively ex vivo.
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: Aneta J
authors.initials: AJ
authors.lastname: Czaplinska
authors.forename: Charles
authors.initials: C
authors.lastname: Sikes
authors.forename: Lin
authors.initials: L
authors.lastname: Han
authors.forename: Evan M
authors.initials: EM
authors.lastname: Johnson
authors.forename: Wei
authors.initials: W
authors.lastname: Qiao
authors.forename: Chaan
authors.initials: C
authors.lastname: Ng
authors.forename: Dianna D
authors.initials: DD
authors.lastname: Cody
authors.forename: William A
authors.initials: WA
authors.lastname: Murphy
authors.forename: Kim-Anh
authors.initials: KA
authors.lastname: Do
authors.forename: Nora M
authors.initials: NM
authors.lastname: Navone
authors.forename: Vikas
authors.initials: V
authors.lastname: Kundra
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000818:Animals; D015519:Bone Density / Q000502:physiology; D001842:Bone and Bones / Q000473:pathology*; D002113:Calcification, Physiologic; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005269:Femur / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D016513:Mice, SCID; D011471:Prostatic Neoplasms / Q000473:pathology*; D055114:X-Ray Microtomography / Q000379:methods*