磁共振扩散张量成像对女性青少年特发性胸腰弯侧凸腰椎间盘的定量分析

A study of diffusion tensor imaging in lumbar intervertebral disc of adolescent idiopathic scoliosis with major thoracolumbar curve

目的探讨磁共振扩散张量成像(DTI)技术在评估女性青少年特发性胸腰弯侧凸(AIS)腰椎间盘(腰1/2-腰5/骶1)早期退变中的价值。方法选取38例临床诊断为AIS的女性患者及与其年龄相匹配的20例女性健康志愿者(对照组)行腰椎间盘常规MRI和DTI检查,根据T2WI图像椎间盘进行Pfirrmann(Pm)分级。将38例AIS患者中腰1-骶1椎间盘未发生任何退变(PmⅠ级)为未退变组(24例),任何节段存在退变(分级高于PmⅠ级)为退变组(14例)。测量AIS两组患者及对照组腰椎间盘的各项异性分数(FA)值和平均弥散率(MD)值,应用ANOVA方差分析及LSD-t检验比较3组腰椎间盘间以及每组各节段椎间盘间FA值和MD值的差异。结果AIS退变组腰椎间盘MD值显著低于未退变组,差异有统计学意义(P<0.05)。AIS两组腰椎间盘MD值显著低于对照组(P<0.05)。退变组腰椎间盘FA值显著高于未退变组,差异有统计学意义(P<0.05)。AIS两组腰椎间盘FA值显著高于对照组,差异有统计学意义(P<0.05)。AIS退变组腰1/2、腰2/3、腰3/4椎间盘的MD值和FA值分别与腰4/5、腰5/骶1椎间盘MD值及FA值差异有统计学意义(P<0.05)。结论DTI结果显示在Pfirrmann分级未见异常的情况下,通过对FA值和MD值的测定能够早期发现和评价女性AIS患者腰椎间盘的退变。

Objective To evaluate the value of diffusion tensor imaging(DTI)to appraise the early degeneration of the lumbar intervertebral discs(IVDs)in female adolescent idiopathic scoliosis with major thoracolumbar curve.Methods Thirtyeight female AIS patients and twenty healthy volunteers(HVs)matched in the gender and age underwent 3T magnetic resonance imaging(MRI)including conventional MRI and DTI sequences.According to T2WI,AIS patients were divided into two groups:One which included L1-S1 lumbar IVDs did not occur any deterioration(Pfirrmann Ⅰ),and another included deterioration of any segments(grade higher than Pfirrmann Ⅰ).The fractional anisotropy(FA)and mean diffusion rate(MD)values of lumbar IVDs were measured and compared between AIS patients and HVs with ANOVA analysis and followed by LSD t-tests.Further analyses were done on the different lumbar segmental with ANOVA analysis and LSD t-tests.Results MD value of the lumbar IVDs in AIS degeneration group was significantly lower than that in the non-degenerative group(P<0.05),while FA value of lumbar IVDs in AIS degeneration group was significantly higher than that in the non-degenerative group(P<0.05).The MD value of the lumbar IVDs in AIS group was significantly lower than that in HVs group(P<0.05),while,FA value of lumbar IVDs in AIS group was significantly higher than that in HVs group(P<0.05).The MD and FA values of L1/2,L2/3,and L3/4 IVDs in AIS degeneration group were significantly different from L4/5 and L5/S1 IVDs,respectively(P<0.05).Conclusion The early degeneration of lumbar IVDs can be demonstrated by FA and MD values in AIS patients even without visible changes on T2-weighted images.DTI can be used as a sensitively noninvasive technique to quantitatively evaluate the degeneration of IVDs in AIS patients.