Quantification of skeletal growth, modeling, and remodeling by in vivo micro computed tomography.
Quantification of skeletal growth, modeling, and remodeling by in vivo micro computed tomography.
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DOI：
10.1016/j.bone.2015.07.037
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发表时间：
2015-12
期刊：
影响因子：
4.1
通讯作者：
Liu XS
中科院分区：
文献类型：
--
作者：
Altman AR;Tseng WJ;de Bakker CMJ;Chandra A;Lan S;Huh BK;Luo S;Leonard MB;Qin L;Liu XS
在这项研究中，我们建立了一个图像分析方案，用于研究骨骼生长过程中皮质骨和松质骨的发育，并在大鼠的体内µCT图像上测试了这一概念。为了评估其有效性，我们将该技术应用于年轻（1个月大）和成年（3个月大）大鼠tibridium与车辆（Veh）或间歇性甲状旁腺激素（PTH）治疗。通过基于其不同的小梁微结构叠加2个连续扫描，我们计算出年轻大鼠胫骨近端的线性生长速率为0.31 mm/天。由于快速生长（12天内3.7 mm），第12天扫描的骨区域与第0天扫描的骨组织没有重叠。相反，在第12天成像的骨区域代表来自生长板的新生成的骨组织。PTH处理的大鼠的新骨具有比Veh处理的大鼠显著更大的骨小梁体积分数、数量和厚度，表明PTH对骨建模的合成代谢作用。与此相反，PTH对成年大鼠松质骨的作用被发现是由PTH对骨重建的合成代谢作用引起的。PTH组（23%）的幼年大鼠胫骨近端皮质骨增厚程度也高于Veh组（14%）。这主要是由骨内膜骨形成和骨小梁合并到皮质中驱动的。该过程可以通过使用图像配准对准局部骨结构变化来可视化。结果，与Veh组相比，PTH治疗后的皮质孔隙减少了31%，极惯性矩增加了22%。最后，我们通过测量从3个月到19个月龄的骨流动远离胫骨近端生长板的距离来监测成年大鼠的纵向骨生长，并发现在16个月内总共生长了3.5 mm。结果表明，这种图像分析方案可以有效地评估骨生长，骨建模和骨重建，并准备转化为临床成像平台。
In this study we established an image analysis scheme for the investigation of cortical and trabecular bone development during skeletal growth and tested this concept on in vivo µCT images of rats. To evaluate its efficacy, we applied the technique to young (1-month-old) and adult (3-month-old) rat tibiae with vehicle (Veh) or intermittent parathyroid hormone (PTH) treatment. By overlaying 2 sequential scans based on their distinct trabecular microarchitecure, we calculated the linear growth rate of young rats to be 0.31 mm/day at the proximal tibia. Due to rapid growth (3.7 mm in 12 days), the scanned bone region at day 12 had no overlap with the bone tissue scanned at day 0. Instead, the imaged bone region at day 12 represented newly generated bone tissue from the growth plate. The new bone of the PTH-treated rats had significantly greater trabecular bone volume fraction, number, and thickness than those of the Veh-treated rats, indicating PTH’s anabolic effect on bone modeling. In contrast, the effect of PTH on adult rat trabecular bone was found to be caused by PTH’s anabolic effect on bone remodeling. The cortical bone at the proximal tibia of young rats also thickened more in the PTH group (23%) than the Veh group (14%). This was primarily driven by endosteal bone formation and coalescence of trabecular bone into the cortex. This process can be visualized by aligning the local bone structural changes using image registration. As a result, the cortex after PTH treatment was 31% less porous, and had a 22% greater polar moment of inertia compared to the Veh group. Lastly, we monitored the longitudinal bone growth in adult rats by measuring the distance of bone flow away from the proximal tibial growth plate from 3 months to 19 months of age and discovered a total of 3.5 mm growth in 16 months. It was demonstrated that this image analysis scheme can efficiently evaluate bone growth, bone modeling, and bone remodeling, and is ready to be translated into a clinical imaging platform.