外侧综合征患者腰骶丛磁共振神经水成像的影像特征分析

Anlysis of magnetic resonance neurography imaging features of the lumbosacral plexus in patients with far-out syndrome

中文关键词:  远外侧综合征  磁共振神经水成像  神经根卡压  腰骶丛  影像学诊断

英文关键词:Far-out syndrome  Magnetic resonance neurography  Nerve root entrapment  Lumbosacral plexus  Imaging diagnosis

中文摘要:

  【摘要】 目的：探讨远外侧综合征（far-out syndrome，FOS）患者腰骶丛磁共振神经水成像（magnetic resonance neurography，MRN）影像特征及其在诊断中的应用价值。方法：回顾性纳入我院经手术确诊的10例FOS患者作为病例组，10例无腰腿痛的志愿者作为对照组。病例组与对照组的年龄、性别均无统计学差异（P＞0.05）。所有受试者均接受腰骶丛MRN检查。观察并比较两组MRN上L5神经根连续性、走行异常拐角情况、近端新月形高信号水肿区和假关节区低信号条索压迫征象；测量标准化L5/S1椎间隙高度、神经根硬脊膜夹角（nerve root-dural angle，NRA）及两侧L5神经根横截面积比值（cross-sectional area ratio，CSA ratio）（病例组为患侧/健侧，对照组为较大侧/较小侧）。统计学分析采用独立样本t检验、Mann-Whitney U检验、配对t检验、Fisher精确检验及Spearman秩相关分析。结果：病例组10例患者L5神经根连续性中断、近端新月形高信号水肿、异常神经拐角，7例假关节区低信号条索压迫征；对照组2例异常神经拐角，无L5神经根连续性中断、近端新月形高信号水肿及假关节区低信号条索压迫征。两组L5神经根连续性、走行异常拐角、新月形高信号水肿区例数均有统计学差异（P<0.001）。病例组标准化L5/S1椎间隙高度中位秩低于对照组[0.73（0.63，0.77） vs 1.00（0.88，1.12），P<0.001]；病例组患侧NRA（23.94°±3.88°）小于健侧（32.52°±4.32°）（P<0.001），且小于对照组左、右侧NRA（分别为26.68°±1.77°和26.70°±3.56°，P<0.05）。病例组L5神经根CSA比值高于对照组（2.32±1.76 vs 1.11±0.65，P<0.001）。标准化椎间隙高度与走行异常拐角存在负相关（rs=-0.850，P<0.001）。结论：FOS患者在腰骶丛MRN上表现为L5神经根在椎间孔外区的连续性中断、近端水肿及走行异常，并可通过NRA和CSA比值提供定量参考。

英文摘要:

  【Abstract】 Objectives: To investigate the magnetic resonance neurography(MRN) imaging characteristics of lumbosacral plexus in patients with far-out syndrome(FOS) and their diagnostic value. Methods: 10 surgically confirmed FOS patients were retrospectively enrolled as the case group, and 10 asymptomatic volunteers were enrolled as the control group. No statistically significant differences in age or sex were found between the two groups(P>0.05). All subjects underwent lumbosacral plexus MRN. Qualitative indicators included L5 nerve root continuity, abnormal angulation of nerve root course, proximal crescent-shaped hyperintense edema, and low-signal cord compression sign at the pseudoarthrosis region were observed on MRN and compared. Quantitative measurements included standardized L5/S1 intervertebral disc height, nerve root-dural angle(NRA), and bilateral L5 nerve root cross-sectional area ratio(CSA ratio, calculated as affected side/unaffected side in the case group and larger side/smaller side in the control group). Statistical analyses were performed using independent samples t-test, Mann-Whitney U test, paired t-test, Fisher′s exact test, and Spearman′s rank correlation test. Results: In the case group, L5 nerve root discontinuity, proximal crescent-shaped hyperintense edema, and abnormal angulation were observed in all 10 patients, and low-signal cord compression sign at the pseudoarthrosis region was observed in 7 patients. In the control group, abnormal angulation was observed in 2 subjects, while none showed nerve root discontinuity, crescent-shaped edema, or low-signal cord compression sign. All qualitative indicators(nerve root discontinuity, abnormal angulation, and crescent-shaped edema) differed significantly between the two groups(P<0.001). The standardized L5/S1 intervertebral disc height in the case group was significantly lower than that in the control group[0.73(0.63, 0.77) vs 1.00(0.88, 1.12), P<0.001]. The NRA on the affected side was significantly smaller than that on the unaffected side in the case group(23.94°±3.88° vs 32.52°±4.32°, P<0.001), and was also significantly smaller than the left and right NRA of the control group(26.68°±1.77° and 26.70°±3.56°, respectively, both P<0.05). The CSA ratio in the case group was significantly higher than that in the control group(2.32±1.76 vs 1.11±0.65, P<0.001). Standardized intervertebral disc height was negatively correlated with abnormal angulation of nerve root course(rs=-0.850, P<0.001). Conclusions: In FOS patients, lumbosacral plexus MRN can directly demonstrate L5 nerve root discontinuity, proximal edema, and abnormal course in the extraforaminal region, and provide quantitative reference through NRA and CSA ratio.