股骨头缺血坏死的MRI诊断价值

Diagnostic value of MRI in avascular necrosis of femoral head

目的探讨磁共振成像(MRI)对股骨头缺血坏死的诊断价值。方法对60例患者分别行MRI、X线、CT及核素扫描检查,使用低场永磁型磁共振设备(0.35T)进行常规断面、常规序列扫描,少数病例进行更多断面及序列如脂肪抑制序列、造影剂增强扫描。对照组为无症状志愿者10例20个股骨头。结果 60例患者120个股骨头中MRI显示96个股骨头诊断为股骨头缺血坏死。根据股骨头缺血坏死的影像表现,分别对早～中期、晚期病例进行分组观察,用χ2检验对照比较各种检查方法阳性率。MRI检查的总阳性率、早-中期及晚期阳性率均明显高于X线、CT及核素检查(P值均小于0.05)。结论与X线、CT及核素扫描比较,MRI检查在股骨头缺血坏死诊断中具有优越性,尤其对于早～中期病变的敏感性高,并指出"双线征"具有诊断特异性。

Objective To evaluate the diagnostic value of magnetic resonance imaging（MRI） in avascular necrosis of femoral head and observe the sensitivity and specificity of MRI examination by comparing X-ray,CT,and radionuclide scanning.Methods 60 patients were examined by MR,X-ray,CT and radionuclide scanning by using the permanent type of magnetic resonance equipment（0.35T）.Both routine cross-section scan and conventional sequential scan were employed.For a small number of cases,more cross section and sequence scans such as fat suppression and contrast-enhancement were conducted.The controls consisted of a group of 10 asymptomatic volunteers with 20 femoral heads.Results Among the 120 femoral heads of the 60 patients,96 were diagnosed as avascular necrosis with MR.Based on the imaging findings of avascular necrosis,we observed closely the early,intermediate and advanced cases respectively.Chi-square test was employed to compare the positive rates in various inspection methods.The total positive rate,the early,intermediate and advanced stage positive rate by MR were significantly higher than those of X-ray,CT and radionuclide examinations.The difference was significant（P 0.05）.Conclusion Compared with X-ray,CT,and radionuclide scanning,the superiority of MRI examination in the diagnosis of avascular necrosis was obvious.It is especially sensitive for the diagnosis of the early and intermediate stage lesions.The ＂ double-line sign＂ has the important specificity for the diagnosis.