Petersen M M, Nielsen P K, Lewin E, Olgaard K
Department of Orthopaedic Surgery, Rigshospitalet, University of Copenhagen, Denmark.
Calcif Tissue Int. 2000 Dec;67(6):455-9. doi: 10.1007/s002230001176.
The feasibility of dual energy X-ray absorptiometry (DXA) using the Norland XR-26 Mark II bone densitometer for measurements of bone mineral content (BMC) and bone mineral density (BMD) in small rats was evaluated. Thirty-two young, isogenic, Lewis rats (weights from 119 g to 227 g) were used; normal rats (n = 7) and rats with low BMD obtained from three different vitamin D-depleted models (n = 25). DXA measurements were performed using the special software for small animals. Duplicate scans of excised femurs performed at 2 mm/second (pixel size of 0.5 mm x 0.5 mm) were very precise measurements with a coefficient of variation (CV) below 1.6% in animals with normal BMD; in rats with low BMD, the CV was significantly higher (P = 0.02-0.04), 7.8% and 4.4% for BMC and BMD, respectively. Regression analysis demonstrated that these measurements were related to the ash weight (R2 > 98.6%). The CV for measurements of the lumbar spine at 10 mm/second (pixel size 0.5 mm x 0.5 mm) was 2.6% and 2.2% for BMC and BMD, respectively in rats with normal BMD, and again higher (P = 0.03-0.14) in rats with low BMD, 7.3% and 4.7%, respectively, for BMC and BMD. Even though low CVs were obtained for total body duplicate scans (scan speed of 20 mm/second and a pixel size of 1.5 mm x 1.5 mm), the measurements were problematic for accuracy because of an overestimation of both BMC and the area of bone. Using these scan parameters the measurements of total body bone mineral could not be recommended in small rats with low BMD.
评估了使用Norland XR - 26 Mark II骨密度仪进行双能X线吸收法（DXA）测量小型大鼠骨矿物质含量（BMC）和骨矿物质密度（BMD）的可行性。使用了32只年轻的、同基因的Lewis大鼠（体重从119克到227克）；正常大鼠（n = 7）和从三种不同维生素D缺乏模型获得的低BMD大鼠（n = 25）。使用小动物专用软件进行DXA测量。以2毫米/秒（像素大小为0.5毫米×0.5毫米）对切除的股骨进行重复扫描，对于BMD正常的动物，测量非常精确，变异系数（CV）低于1.6%；对于低BMD大鼠，CV显著更高（P = 0.02 - 0.04），BMC和BMD的CV分别为7.8%和4.4%。回归分析表明这些测量与灰重相关（R2 > 98.6%）。在BMD正常的大鼠中，以10毫米/秒（像素大小0.5毫米×0.5毫米）测量腰椎时，BMC和BMD的CV分别为2.6%和2.2%，在低BMD大鼠中再次更高（P = 0.03 - 0.14），BMC和BMD分别为7.3%和4.7%。尽管全身重复扫描（扫描速度为20毫米/秒，像素大小为1.5毫米×1.5毫米）获得了低CV，但由于BMC和骨面积均被高估，测量的准确性存在问题。使用这些扫描参数，不建议对低BMD的小型大鼠进行全身骨矿物质测量。
