Phan Catherine M, Matsuura Maiko, Bauer Jan S, Dunn Timothy C, Newitt David, Lochmueller Eva M, Eckstein Felix, Majumdar Sharmila, Link Thomas M
Department of Radiology, University of California, San Francisco, 400 Parnassus Ave, A 367, Box 0628, San Francisco, CA 94143-0628, USA.
Radiology. 2006 May;239(2):488-96. doi: 10.1148/radiol.2392050574. Epub 2006 Mar 28.
To investigate in vitro the calcaneal trabecular bone structure in elderly human donors with high spatial resolution magnetic resonance (MR) imaging at 3.0 T and 1.5 T, to quantitatively compare MR measures of bone microarchitecture with those from micro-computed tomography (CT), and to compare the performance of 3.0-T MR imaging with that of 1.5-T MR imaging in differentiating donors with spinal fractures from those without spinal fractures.
The study was performed in line with institutional and legislative requirements; all donors had dedicated their body for educational and research purposes prior to death. Sagittal MR images of 49 human calcaneus cadaveric specimens were obtained (mean age of donors, 79.5 years +/- 11 [standard deviation]; 26 male donors, 23 female donors). After the spatial coregistering of images acquired at 3.0-T and 1.5-T MR imaging, the signal-to-noise-ratios and structural parameters obtained at each magnetic field strength were compared in corresponding sections. Micro-CT was performed on calcaneus cores obtained from corresponding regions in 40 cadaveric specimens. Vertebral deformities of the thoracic and lumbar spine were radiographically classified by using the spinal fracture index. Diagnostic performance of the structural parameters in differentiating donors with vertebral fractures from those without was assessed by using receiver operator characteristic (ROC) analysis, including area under the ROC curve (A(z)).
Correlations between structural parameters at 3.0-T MR imaging and those at micro-CT were significantly higher (P < .05) than correlations between structural parameters at 1.5-T MR imaging and those at micro-CT (trabecular thickness, r = 0.76 at 3.0 T vs r = 0.57 at 1.5 T). Trabecular dimensions were amplified at 3.0 T because of increasing susceptibility artifacts. Also, higher ROC values were found for structural parameters at 3.0 T than at 1.5 T, but differences were not significant (trabecular thickness, A(z) = 0.75 at 3.0 T vs A(z) = 0.66 at 1.5 T, P > .05).
MR imaging at 3.0 T provided a better measure of the trabecular bone structure than did MR imaging at 1.5 T. There was a trend for better differentiation of donors with from those without osteoporotic vertebral fractures at 3.0 T than at 1.5 T.
采用3.0T和1.5T高空间分辨率磁共振（MR）成像技术对老年人类供体的跟骨小梁骨结构进行体外研究，将骨微结构的MR测量值与显微计算机断层扫描（CT）测量值进行定量比较，并比较3.0T MR成像与1.5T MR成像在区分有脊柱骨折和无脊柱骨折供体方面的性能。
本研究符合机构和法律要求；所有供体在生前已将其遗体奉献于教育和研究目的。获取了49例人类跟骨尸体标本的矢状面MR图像（供体平均年龄79.5岁±11岁[标准差]；男性供体26例，女性供体23例）。在对3.0T和1.5T MR成像获取的图像进行空间配准后，比较了在每个磁场强度下获得的信噪比和结构参数在相应层面的情况。对40例尸体标本相应区域获取的跟骨核心进行了显微CT检查。采用脊柱骨折指数对胸腰椎椎体畸形进行影像学分类。通过使用接受者操作特征（ROC）分析评估结构参数在区分有椎体骨折和无椎体骨折供体方面的诊断性能，包括ROC曲线下面积（A(z)）。
3.0T MR成像的结构参数与显微CT的结构参数之间的相关性显著高于1.5T MR成像的结构参数与显微CT的结构参数之间的相关性（P < 0.05）（小梁厚度，3.0T时r = 0.76，1.5T时r = 0.57）。由于敏感性伪影增加，小梁尺寸在3.0T时被放大。此外，3.0T时结构参数的ROC值高于1.5T，但差异不显著（小梁厚度，3.0T时A(z) = 0.75，1.5T时A(z) = 0.66，P > 0.05）。
3.0T MR成像比1.5T MR成像能更好地测量小梁骨结构。在区分有和无骨质疏松性椎体骨折供体方面，3.0T时比1.5T时有更好区分的趋势。
