title: Vertebral blood perfusion reduction associated with vertebral bone mineral density reduction: a dynamic contrast-enhanced MRI study in a rat orchiectomy model.
abstract: OBJECTIVE
  To investigate the relationship between vertebral blood perfusion and vertebral bone mineral density (BMD) in a rat orchiectomy (ORX) model.
  
  
  METHODS
  Nine 6-month-old male Wistar-Kyoto rats were used. Computed tomography (CT) bone densitometry and dynamic MRI were performed at baseline and four weeks post-ORX. MRI was performed on a 1.5 T clinical MR scanner with a small surface coil placed under the rat lumbar spine region. A sagittal midsection of the lumbar spine was prescribed. Dynamic MRI was performed after a bolus injection of gadolinium-tetraazacyclododecane tetraacetic acid (Gd-DOTA) (0.3 mmol/kg) administered through a tail vein cannula. At a temporal resolution of 0.6 seconds, 800 images were acquired. Regions-of-interest were drawn comprising the medullary component of lumbar vertebrae L3-L6. Maximum enhancement was analyzed.
  
  
  RESULTS
  Satisfactory CT and MRI data for analysis was obtained in all animals. Vertebral BMD decreased by 16.6% at four weeks post-ORX (1.134 +/- 0.035 vs. 0.946 +/- 0.027 g/cm(3), P = 0.008). MRI maximum enhancement decreased by 17% at four weeks post-ORX (151.5 +/- 12.0% vs. 125.8 +/- 9.9%, P = 0.015).
  
  
  CONCLUSIONS
  Vertebral blood perfusion reduction is associated with vertebral BMD reduction in a male rat osteoporosis model. Perfusion MRI provides a new investigative technique for osteoporosis experimental research.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, People's Republic of China. yixiang_wang@cuhk.edu.hk
authors.forename: Yi-Xiang J
authors.initials: YX
authors.lastname: Wang
authors.forename: Ya-Feng
authors.initials: YF
authors.lastname: Zhang
authors.forename: James F
authors.initials: JF
authors.lastname: Griffith
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Kwok
authors.forename: Ling
authors.initials: L
authors.lastname: Qin
authors.forename: Anil T
authors.initials: AT
authors.lastname: Ahuja
mesh_terms: D000818:Animals; D015519:Bone Density; D003287:Contrast Media; D006571:Heterocyclic Compounds; D008159:Lumbar Vertebrae / Q000098:blood supply*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009919:Orchiectomy; D009942:Organometallic Compounds; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate