Wehrli F W, Hopkins J A, Hwang S N, Song H K, Snyder P J, Haddad J G
Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, 1 Founders, Philadelphia, PA 19104, USA.
Radiology. 2000 Nov;217(2):527-38. doi: 10.1148/radiology.217.2.r00nv20527.
To evaluation the cancellous bone-induced intravoxel spin dephasing rate (R2') and its relationship to bone mineral density and marrow fat and to examine these parameters as predictors of vertebral fracture status.
R2' and R2, the rate constants for reversible and irreversible spin dephasing, and marrow fat fraction were measured in the lumbar vertebrae and proximal femur. One hundred thirty-nine subjects (mean age, 62.4 years +/- 11.4 [SD]; 33 men, 106 women) had spinal dual-energy x-ray absorptiometric bone mineral density (BMD) T scores ranging from +3 to -5. R2', BMD, and bone marrow composition as determinants of vertebral fracture status were examined.
Strongest single predictors of fracture status for BMD and R2' were the Ward triangle (r(2) = 0.48) and trochanter (r(2) = 0.37), respectively. Combined, the two parameters and sites increased fracture prediction (r(2) = 0. 62), whereas the combination of multiple BMD sites did not. Multivariate regression involving marrow fat fraction further improved fracture status prediction. R2' was correlated with BMD at all sites, although slopes differed by a factor of up to 2.5, which reflected differences in trabecular orientation relative to the static field. R2, the true transverse relaxation rate, was negatively correlated with marrow fat fraction. A non-age-related increase in marrow fat fraction in osteoporosis parallels earlier findings in animal models.
Cancellous bone marrow R2' measured in the proximal femur provides information, which, with BMD, improves prediction of vertebral fracture status.
评估松质骨诱导的体素内自旋去相位率（R2'）及其与骨矿物质密度和骨髓脂肪的关系，并检验这些参数作为椎体骨折状态预测指标的情况。
在腰椎和股骨近端测量R2'以及可逆和不可逆自旋去相位的速率常数R2，还有骨髓脂肪分数。139名受试者（平均年龄62.4岁±11.4[标准差]；33名男性，106名女性）的脊柱双能X线吸收法骨矿物质密度（BMD）T值范围为+3至-5。检验了R2'、BMD和骨髓成分作为椎体骨折状态的决定因素。
BMD和R2'预测骨折状态的最强单一指标分别是沃德三角（r(2)=0.48）和转子（r(2)=0.37）。两者参数和部位相结合可提高骨折预测能力（r(2)=0.62），而多个BMD部位的组合则不能。涉及骨髓脂肪分数的多变量回归进一步改善了骨折状态预测。R2'与所有部位的BMD均相关，尽管斜率相差高达2.5倍，这反映了小梁相对于静磁场方向的差异。真正的横向弛豫率R2与骨髓脂肪分数呈负相关。骨质疏松症患者中与年龄无关的骨髓脂肪分数增加与动物模型早期的研究结果相似。
在股骨近端测量的松质骨骨髓R2'提供了相关信息，与BMD一起可改善椎体骨折状态的预测。
