宽管征在MR I诊断腰椎双侧椎弓峡部不连中的意义  

Importance of wide canal sign in the MR diagnosis of lumbar isthmic spondylolisthesis

作　　者：张联合[1] 杨岗[1] 张士良[1] 

机构地区：[1]中国人民武装警察部队浙江省总队杭州医院放射科,浙江杭州310051

出　　处：《实用放射学杂志》2014年第4期645-648,共4页Journal of Practical Radiology

摘　　要：目的：探讨第5腰椎水平椎管前后径增宽（宽管征）在 MRI诊断椎弓峡部不连中的意义。方法随机收集经 X线平片和/或CT证实的 L5双侧椎弓峡部不连100例,同时收集年龄、性别匹配的无椎弓峡部不连组100例作为对照组,在 T1 WI 正中矢状位 MRI图像上测量 L1、L5椎体的正中水平椎管矢状径,并计算 L5椎体平面的椎管正中矢状径与 L1椎体平面正中矢状径的比率,比较不连组和对照组的 L5/L1椎体平面椎管矢状径率,并进行 ROC曲线分析。结果椎弓峡部不连组 L5椎体平面的平均正中矢状径为（22.3＆#177;1.34）mm,平均正中椎管矢状径比率平均为1.32；而对照组平均正中椎管矢状径为（18.8＆#177;1.57）mm,平均正中椎管矢状径比率平均为1.12；经统计学检验,两者有显著差异（P 值为0.000）；ROC曲线下面积为0.964,当截断点选择为1.25时,灵敏度为88%,特异度为90%,两者之和值最大（1.78）。结论正中椎管矢状比率超过1.25定义为宽管征阳性,是诊断 L5双侧椎弓峡部不连的特异性征象,且直观、容易掌握,能有效地减少断椎弓峡部不连的漏误诊。Objective To evaluate the importance of wide canal sign （increased anteroposterior diameter of the spinal canal at L5） in the MR diagnosis of lumbar isthmic spondylolisthesis.Methods One hundred cases of bilateral isthmic spondylolisthesis at L5 confirmed with conventional radiography and/or CT were randomly collected.Another age and sex matched 100 cases without spon-dylolisthesis were collected as control group.The sagittal canal diameters at the L1 and L5 levels were measured and analyzed for all 100 cases of bilateral isthmic spondylolisthesis and 100 control subjects.For each group,the sagittal canal ratio（defined as the maxi-mum anteroposterior diameter of the canal at L5 level divided by the diameter of the canal at L1 ）was calculated and compared be-tween the two groups ,and anylyzed with ROC curve.Results The mean midline sagittal anteroposterior diameter was （22.3 ＆#177; 1.34）mm at L5 in patients with lumbar isthmic spondylolisthesis,and （18.8＆#177;1.57）mm in the control subjects.The sagittal canal ratio was 1.32 in the isthmic spondylolisthesis group and 1.12 in the control subjects,which was different significantly.ROC curve illustrated that the sagittal canal ratio 1.25 was a most meanful point with 88% sensitivity and 90% specificity.Conclusion The sag-ittal canal ratio at L5 is bigger than 1.25 meaning abnormally increased sagittal canal diameter （wide canal sign）,which specifically indicates the presence of bilateral pars interarticularis defects.Using this sign can help to make correct MR diagnosis and differential diagnosis of isthmic spondylolisthesis .

关 键 词：椎弓峡部不连 磁共振成像 椎管 

分 类 号：R681.5[医药卫生—骨科学] R445.2[医药卫生—外科学]