Longitudinal HR-pQCT and Image Registration Detects Endocortical Bone Loss in Kidney Transplantation Patients
Longitudinal HR-pQCT and Image Registration Detects Endocortical Bone Loss in Kidney Transplantation Patients
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DOI：
10.1002/jbmr.2358
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发表时间：
2015-03-01
影响因子：
6.2
通讯作者：
Nickolas, Thomas L.
中科院分区：
文献类型：
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作者：
Nishiyama, Kyle K.;Pauchard, Yves;Nickolas, Thomas L.
接受肾移植的慢性肾病（CKD）患者会出现骨质流失和骨折风险增加。然而，这种骨丢失的机制尚不清楚。我们的目的是使用图像配准来定义皮质，以评估首次肾移植患者的皮质孔隙率（Ct. Po）变化。我们获得了甲状旁腺激素（PTH）和骨转换标志物的系列测量值，并使用高分辨率外周定量计算机断层扫描（HR-pQCT）对31例患者（21例男性，10例女性;年龄51.9 ± 13.4岁）在移植时和1年后的桡骨远端和胫骨进行扫描。使用全自动、基于强度的图像配准框架对齐基线和1年图像。我们比较了三种定义皮质感兴趣区（ROI）并量化变化的方法：1）皮质骨在基线和随访扫描中独立定义; 2）皮质骨定义为常见的皮质ROI; 3）基线皮质ROI结转至1年随访（基线索引）。通过独立定义的ROI，桡骨的Ct. Po增加了11.7%，胫骨增加了9.1%，而通过共同ROI，桡骨的Ct. Po增加了14.6%，胫骨增加了9.1%。通过基线索引ROI（可了解皮质内区域的变化），桡骨Ct. Po增加63.4%，胫骨增加17.6%。我们发现Ct. Po的变化与桡骨骨形成和骨吸收标志物之间存在显著关系。最强的协会被发现之间的标记和Ct。Po使用基线指数法。我们的结论是，Ct. Po增加整个皮质肾移植后，这种增加是特别显着的皮质内表面。这些方法可能被证明对所有HR-pQCT纵向研究有用，特别是当预期皮质内区域发生变化时。(C)2014年美国骨与矿物质研究学会。
Patients with chronic kidney disease (CKD) who undergo kidney transplantation experience bone loss and increased risk of fracture. However, the mechanisms of this bone loss are unclear. Our objective was to use image registration to define the cortex to assess changes in cortical porosity (Ct.Po) in patients undergoing first-time kidney transplantation. We obtained serial measurements of parathyroid hormone (PTH) and bone turnover markers and used high-resolution peripheral quantitative computed tomography (HR-pQCT) to scan the distal radius and tibia in 31 patients (21 men, 10 women; aged 51.9 +/- 13.4 years) at transplant and after 1 year. Baseline and 1-year images were aligned using a fully automated, intensity-based image registration framework. We compared three methods to define the cortical region of interest (ROI) and quantify the changes: 1) cortical bone was independently defined in baseline and follow-up scans; 2) cortical bone was defined as the common cortical ROI; and 3) the cortical ROI at baseline was carried forward to 1-year follow-up (baseline-indexed). By the independently defined ROI, Ct.Po increased 11.7% at the radius and 9.1% at the tibia, whereas by the common ROI, Ct.Po increased 14.6% at the radius and 9.1% at the tibia. By the baseline-indexed ROI, which provides insight into changes at the endocortical region, Ct.Po increased 63.4% at the radius and 17.6% at the tibia. We found significant relationships between changes in Ct.Po and bone formation and resorption markers at the radius. The strongest associations were found between markers and Ct.Po using the baseline-index method. We conclude that Ct.Po increases throughout the cortex after kidney transplant, and this increase is particularly marked at the endocortical surface. These methods may prove useful for all HR-pQCT longitudinal studies, particularly when changes are expected at the endocortical region. (C) 2014 American Society for Bone and Mineral Research.