To investigate the relationship between vertebral blood perfusion and vertebral bone mineral density (BMD) in a rat orchiectomy (ORX) model.Materials and 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 1.5T 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/cm3, 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).Conclusion:
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. J. Magn. Reson. Imaging 2008;28:1515–1518. © 2008 Wiley-Liss, Inc.