Drum Marti G, Les Clifford M, Park Richard D, McIlwraith C Wayne, Kawcak Christopher E
Department of Small Animal Clinical Sciences, Veteriary Teaching Hospital, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Am J Vet Res. 2008 Jul;69(7):891-3. doi: 10.2460/ajvr.69.7.891.
To evaluate whether cutting equine subchondral bone to demarcate specific regions of interest (ROIs) influences the mean density for that bone as measured via quantitative computed tomography (QCT). Sample population-2 metacarpophalangeal joints from equine cadavers.
The distal portion of the third metacarpal bone of each intact metacarpophalangeal joint was scanned via CT to simulate in vivo conditions. Each joint was subsequently disarticulated and dissected, and the distal portion of the dissected third metacarpal bone in air was scanned. Then, six 1-cm(2) areas representing ROIs were cut into the distal condylar surfaces to depths of approximately 1 cm, and the bone was scanned again. Three-dimensional CT models of the 3 bone preparations were generated for each third metacarpal bone on the basis of data from each set of scan images, and densities of the 6 ROIs were measured. Mean bone densities for the 6 ROIs were compared among models of intact, dissected, and cut third metacarpal bone scans.
Mean bone density was significantly lower in cut bone preparations, compared with that in intact or dissected bone. Differences between mean bone densities for intact and dissected bone preparations were not significant.
Cutting subchondral bone to demarcate specific ROIs prior to CT imaging significantly lowered mean bone density as measured via QCT and thus introduced substantial artifacts. These findings have direct implications on techniques for CT modeling of equine subchondral bone in the characterization of joint diseases in horses.
评估切割马的软骨下骨以划定特定感兴趣区域（ROI）是否会影响通过定量计算机断层扫描（QCT）测量的该骨骼的平均密度。样本群体——来自马尸体的2个掌指关节。
对每个完整掌指关节的第三掌骨远端进行CT扫描以模拟体内情况。随后将每个关节分离并解剖，对空气中解剖后的第三掌骨远端进行扫描。然后，在远端髁表面切割出6个代表ROI的1平方厘米区域，深度约为1厘米，之后再次对骨骼进行扫描。根据每组扫描图像的数据，为每根第三掌骨生成3种骨骼标本的三维CT模型，并测量6个ROI的密度。比较完整、解剖和切割后的第三掌骨扫描模型中6个ROI的平均骨密度。
与完整或解剖后的骨骼相比，切割后的骨骼标本中的平均骨密度显著更低。完整和解剖后的骨骼标本的平均骨密度之间的差异不显著。
在CT成像前切割软骨下骨以划定特定ROI会显著降低通过QCT测量的平均骨密度，从而引入大量伪影。这些发现对马关节疾病特征化过程中马软骨下骨CT建模技术具有直接影响。
