MicroCT扫描正常月骨的显微形态学研究

Microstructure study of normal lutes with microCT

目的应用MicroCT对正常月骨进行扫描和三维重建，分析正常月骨骨小梁的显微结构特点。方法使用MicroCT对5例新鲜的正常月骨标本进行扫描，以DataViewer软件对扫描图像进行三维重建，确定并统计滋养孔。以CTAnalyser软件对横断面图像进行重建，分别选取9个兴趣区（200×200×40，pixel^3），计算各兴趣区内骨小梁骨组织密度（BV／TV）、骨组织表面积（BS）、骨面积体积比（BS／BV）、骨小梁厚度（Tb.Th）、骨小梁分离度（Tb．sp）、结构模型指数（SMI）、异向度（DA）等参数，分析骨小梁结构特点。结果MicroCT扫描数据经过三维重建后能够清晰显示正常月骨骨小梁的显微结构，我们发现冠状面上月骨骨小梁由远端向近端呈放射状分布，垂直于桡月关节面与头月关节面。放射状骨小梁为板层状，通过横形与斜形棒状骨小梁组成复杂的网状结构。头月关节面软骨下骨小梁为平行于关节面的板层状结构，十分致密，并向掌、背侧延伸，通过一处移行带转化为网状骨小梁。该结构与掌、背侧远极骨小梁的B、r／Tv、BS／BV、SMI、DA值差异均有统计学意义（P〈0．05）、Tb．Th值差异无统计学意义（P〉0．05），该结构与掌侧远极Tb．Sp值差异无统计学意义（P〉0．05），而与背侧远极11）．Sp差异有统计学意义（P〈0．05）。本组月骨标本的掌侧滋养孔平均为（2．80±0．84）个，平均直径（1．87±0．21）mm；背侧滋养孔平均（1．60±1．52）个，平均直径（1．27±0．21）mm。掌、背侧滋养孔直径差异有统计学意义（P〈0．05），但掌、背侧滋养孔数目差异无统计学意义（P〉0．05）。结论应用MicroCT可以获得正常月骨骨小梁的精细显微图像，并可用于分析月骨的滋养孔，正常月骨远侧关节面的掌、背侧骨小梁结构明显弱于中央部位。

Objective To analyze the micro-structures of normal lunates with micro-computer tomography （microCT）. Methods MicroCT scans were obtained from 5 fresh cadaver normal lunates. The scanned data were reconstructed with the DateViewer software, with which the nutrient foramina were analyzed. After being reconstructed with the CT Analyser software, 9 regions of interest （200 × 200 ×40, pixel3 ） were chosen in a transverse plane so that the results of percent bone volume （BV/TV）, bone surface （BS）, bone surface/volume ratio （BS/BV）, trabecular thickness （Tb. Th）, trabecular separation （Tb. Sp）, structure model index （SMI）, degree of anisotropy （DA） of ROIs could be obtained. Results High-resolution images of the trabecular micro-structures of normal lunates were obtained after 3D reconstruction of microCT scans of the lunate. The coronal 3D images demonstrated radially-arranged trabecular bone of normal lunate, spanning from the distal cortex to the proximal and perpendicular to the articular surface. The radially-arranged trabecular bone demonstrated lamellar-like structure, forming a complex net-like micro-construction combined with rod-shaped trabecular bones in other directions. The distal subchondral bone plate demonstrated lamellar-like compact construction, extending to the volar and dorsal cortex and paralleling with the distal articular surface. The distal subchondral bone plate transformed net-like construction through a transition zone. The distal lamellar-like compact construction had statistically significant differences in BT/TV, BS/BV, SMI, DA （ P 〈 0.05）, but no significant difference in Tb. Th （ P 〉 0.05）, when it was compared with the ROIs in volar and dorsal ends of the distal cortex. There was also statistically significant difference in Th. Sp （ P 〈 0.05） compared with the ROI in the dorsal end of the distal cortex, but no significant difference in Tb. Sp （ P 〉 0.05） compared with the ROI in the volar end. There were （2.80 ± 0.84） nutrient foramina on volar cortex of the lunates with an average diameter of （1.87±0.21） mm, and （1.60 ±1.52） nutrient foramina on the dorsal cortex with an average diameter of （1.27 ±0.21 ） mm. The differences of diameter between the volar and the dorsal foramina was significant （P 〈 0.05）. However, there was no significant difference regarding to the nutrient foramina between the volar and the dorsal cortex. Conclusion High-resolution images of the normal lunates can be obtained with mieroCT to analyze the trabecular micro-structures and nutrient foramina. The trabectdar bones of the volar and dorsal distal ends have lower intensity than those of the distal central subchondral bone plate.