运动负荷对正常腰椎间盘MR扩散张量成像表现弥散系数和各向异性分数的影响

目的探讨运动负荷对正常腰椎间盘MR扩散张量成像（DTI）中表观弥散系数（ADC）和部分各向异性（FA）的影响。方法
对30例健康志愿者行常规矢状位FSE/T2WI成像及运动负荷前后DTI成像，其中男性24名，女性6名，年龄19~25岁。在MR常
规T2WI序列上对腰椎间盘按Pfirrmann 标准进行退变分级，利用DTI原始数据重组b0图、ADC图及FA图，测量并比较运动负
荷前后ADC值、FA值的变化。统计方法使用重复测量数据的方差分析，P<0.05 具有统计学意义。结果30 名志愿者，观测
L1~S1共计150个椎间盘，将其中27例腰椎间盘Pfirrminn分级均为Ⅱ级的受试者纳入研究。腰椎间盘平均ADC值运动负荷前
为（1.99±0.18）×10-3 mm2/s，运动负荷后为（1.93±0.17）×10-3 mm2/s，较运动负荷前下降，差异具有统计学意义（P<0.05）；腰椎间盘
平均FA值运动负荷前为0.155±0.059，运动负荷后为0.163±0.017，较运动负荷前升高，差异不具有统计学意义（P>0.05）。结论
磁共振DTI成像可以定量分析运动负荷后腰椎间盘水分子扩散能力及各向异性程度的变化。运动负荷后，腰椎间盘ADC值下
降，FA值升高，其中ADC值的变化更为敏感。

Effect of exercise load on apparent diffusion coefficient and fractional anisotropy ofnormal lumbar intervertebral discs in diffusion tensor imaging

Objective To investigate the effect of exercise load on apparent diffusion coefficient (ADC) and fractional anisotropy
(FA) of normal lumbar intervertebral discs in magnetic resonance (MR) diffusion tensor imaging (DTI) . Methods Thirty
healthy volunteers (24 males and 6 females, aged 19 to 25 years) underwent examinations with MR T2WI and DTI of the
lumbar intervertebral discs before and after exercise load. Pfirrmann grading was evaluated with T2WI, and the B0 map, ADC
map and FA map were reconstructed based on the DTI data to investigate the changes in ADC and FA after exercise. Results
Of the 30 volunteers (150 intervertebral discs) receiving the examination, 27 with discs of Pfirrminn grade II were included for
analysis. In these 27 volunteers, the average ADC and FA before exercise were (1.99 ± 0.18) × 10-3 mm2/s and 0.155 ± 0.059,
respectively. After exercise, ADC was lowered significantly to (1.93 ± 0.17) × 10-3 mm2/s (P<0.05) and FA increased slightly to
0.1623 ± 0.017 (P>0.05). Conclusion DTI allows quantitatively analysis of the changes in water molecular diffusion and
anisotropy of the lumbar intervertebral discs after exercise load, which can cause a decreased ADC and a increased FA value,
and the change of ADC is more sensitive to exercise load.