正常腰椎间盘纤维环MR纤维示踪图的特点

A study on the microstructure of normal annulus fiber of lumbar intervertebral discs with fiber tractography

目的研究扩散张量成像纤维示踪技术(FT)无创显示正常腰椎间盘纤维环微观结构的能力。方法随机选取30例年轻健康志愿者,进行矢状位T1WI、T2WI及轴位T2WI、DTI扫描,由两名放射科医师对所得腰椎间盘进行Pfirrmann分级,二者一致判定为PfirrmannⅠ~Ⅱ级的腰椎间盘纳入研究,利用DTI原始数据将所得腰椎间盘的图像进行后处理得到其椎间盘的FT图,按照FT图上纤维环的形态、连续性制定FT图分型标准,将其分为规则连续型和规则不连续型。统计学方法采用SPSS 24.0软件包进行χ~2分析。结果共有90个正常腰椎间盘(PfirrmannⅠ~Ⅱ级)纳入研究。PfirrmannⅠ级腰椎间盘32个,其中纤维环FT图规则连续型16个、规则不连续型16个;PfirrmannⅡ级腰椎间盘58个,其中纤维环FT图规则连续型30个、规则不连续型28个;经χ~2检验,χ~2=0.025,P=0.88,差异无统计学意义。结论正常腰椎间盘纤维环FT图分为规则连续型和规则不连续型两种,为研究病变腰椎间盘纤维环提供参考信息。

Objective To study the feasibility of using fiber tractography（FT）acquired with diffusion tensor imaging（DTI）for the detecting normal annulus fiber structure in the lumbar intervertebral discs noninvasively. Methods 30 healthy volunteers were recruited. Sagittal T1WI, T2WI, axial T2WI and DTI scans were performed. All images were reviewed by two radiologists and classified as grade Ⅰ-Ⅱ according to Pfirrmann’s classification system. FT maps of lumbar intervertebral discs were reconstructed using the DTI data. FT maps were classified as either continuous or discontinuous by the morphological characteristics and continuity of annulus fibers in FT maps. The Chi-square test statistic was performed using SPSS 24.0 software package, P 〈 0.05 was considered as statistically significant. Results There were 90 normal lumbar intervertebral discs （Pfirrmann Ⅰ - Ⅱ）included in the study in total. The number of lumbar intervertebral discs classified as grade Ⅰ - Ⅱ were 32 and 58 respectively. There were 16 annulus fibrous present continuous and 16 present discontinuous in grade Ⅰ ; 30 annulus fibrous present continuous and 58 present discontinuous in grade Ⅱ（χ2 = 0.025, P = 0.88） , there was no significant difference. Conclusions FT maps of normal annulus fibrous of lumbar intervertebral disc were classified as either continuous or discontinuous. It lays the foundation for study on abnormal annulus fibrous.