离子造影剂增强Micro-CT扫描对大鼠关节软骨形态的定量分析

利用Micro-CT技术的较高分辨精度,探索一种新的测量小动物关节软骨形态的方法,为进一步利用小动物模型开展关节软骨的损伤和退变等研究提供基础。选择不同浓度的造影剂及Micro-CT扫描条件,通过造影剂对比增强Micro-CT扫描大鼠膝关节,对大鼠股骨远端关节软骨进行手动分割、重建,得到软骨3D模型,利用重建得到的3D模型,对软骨的厚度和体积等形态学参数进行无创定量分析。根据造影剂、软骨和软骨下骨对X射线吸收的平均相对衰减值差异,确定30%的离子造影剂浓度为最佳。利用该浓度对4个不同的正常大鼠关节软骨进行扫描和重建,分析获得关节软骨的体积和厚度,并求得关节软骨体积和厚度的变异系数均方根分别为7.3%和6.1%。结果提示,利用造影剂增强Micro-CT扫描能够对软骨形态重要参数厚度、体积等进行定量评价。

Quantitative Assessment of the Morphology of Articular Cartilage in Rat by an Ionic Contrast Agent-enhanced Micro-CT Scanning

Based on the high resolution of Micro- CT,to explore a novel method for measuring the morphology of articular cartilage in small animals,providing a basis to develop further research on the articular cartilage degeneration and injury using small animals’ model. The different concentration of contrast agent and scanning condition of Micro- CT were selected. By an ionic contrast agent- enhanced micro- CT scanning of rat distal femur,the 3D model of articular cartilage was remodeled after segmentation and reconstruction. And then,using this 3D model,the cartilage morphology in the rat such as thickness and volume was assessed quantitatively and nondestructively. According to the different X- ray attenuation（ CT value） of contrast agent,cartilage and calcified bone,30% contrast agent was determined as the optimal concentration. Under this condition,4 rats’ femurs were scanned and remodeled,the volume and thickness of articular cartilage were determined. The root- mean- square of coefficient variance for volume and thickness was 7. 3% and 6. 1%,respectively. Results show that using contrast agent enhanced Micro- CT scanning is an effective method to quantitatively evaluate the articular cartilage morphology including thickness and volume.