MRI在腰椎间盘突出症伴多裂肌改变中的应用价值

The value of MRI in evaluating the lumbar disc herniation with multifidus muscle changes

【目的】探讨磁共振成像在外侧型腰椎间盘突出症压迫脊神经与多裂肌萎缩和脂肪浸润相关性中的应用价值。【方法】回顾性分析我院经手术证实的60例单侧外侧型腰椎间盘突出症患者的临床和MRI资料,根据病程长短分为A、B、C三组,测量病变层面总多裂肌横截面积(total cross-sectional area,TCSA)、无脂肪多裂肌横截面积(fat-free CSA,FCSA)、多裂肌至椎弓板的垂直距离(distance of the multifidus muscle to the lamina,MLD),并计算FCSA/TCSA、MLD比(患侧MLD/健侧MLD)、FCSA/TCSA比[(患侧FCSA/TCSA)/(健侧FCSA/TCSA)]。ROC曲线用于计算诊断阈值和曲线下面积(area under the curve,AUC)。【结果】三组组内MLD患侧大于健侧(P<0.01),C组FCSA/TCSA患侧小于健侧(P<0.05)。三组之间FCSA/TCSA比和MLD比差异有统计学意义(P<0.05),且呈负相关关系(r=-0.34,P<0.05)。ROC曲线上MLD的诊断阈值是6.74 mm,敏感度和特异度分别为73.3%和60.0%,AUC为0.682(P<0.05)。【结论】MRI新指标可以有效评估外侧型腰椎间盘突出症所致的脊神经压迫、多裂肌萎缩及脂肪浸润,对腰椎间盘突出症的诊断和评价有重要的指导作用。

【Objective】To explore the value of magnetic resonance imaging（MRI） in evaluating the correlation between spinal nerve compression due to lateral lumbar disc hernia and multifidus muscle atrophy as well as fat infiltration.【Methods】The clinical and MRI data of 60 patients with unilateral lumbar disc hernia proved by operation were retrospectively analyzed in our hospital. According to the duration of the disease, the subjects were divided into A, B and C groups. The total cross-sectional area（TCSA） and fat-free CSA（FCSA） of the multifidus muscle and perpendicular distance of the multifidus muscle to the lamina（MLD） were measured at the hernia level. Then FCSA/TCSA, MLD ratio（diseased-side MLD/normal-side MLD） and FCSA/TCSA ratio [（diseased-side FCSA/TCSA）/（normal-side FCSA/TCSA）] were calculated. ROC curves were generated to calculate the diagnostic cut-off value and area under the curve（AUC）.【Results】MLD in the diseased side was larger than that in the normal side in the three groups（P〈0.01） and FCSA/TCSA in the diseased side was smaller than that in the normal side in group C（P0.05）. The differences of FCSA/TCSA and MLD ratio among the three groups were statistically significant（P0.05） and there was a negative correlation in them（r=-0.34, P0.05）. The cut-off value for the MLD measurements was 6.74 mm（sensitivity=73.3%, specificity=60.0%）, and AUC is 0.682（P0.05）.【Conclusion】New indexes of MRI can be used to effectively evaluate the spinal nerve compression, multifidus muscle atrophy and fat infiltration due to lateral lumbar disc hernia, which play an important role in guiding the diagnosis and evaluation of lumbar disc hernia.