弥散加权成像对强直性脊柱炎活动性骶髂关节炎的诊断价值

Role of diffusion-weighted MRI in detecting active sacroiliitis of ankylosing spondylitis

目的研究弥散加权成像(diffusion-weighted imaging,DWI)在强直性脊柱炎(ankylosing spondylitis,AS)活动性骶髂关节炎的诊断价值。方法根据修订的纽约标准,78例临床诊断为AS的慢性腰背痛患者,由风湿科医生根据Bath强直性脊柱炎疾病活动指数(BASDAI)评分及实验室指标,将病例分为活动组(34例)及稳定组(44例),25例健康成年人作为对照组。作MRI斜冠状位扫描,常规序列包括T1快速自旋回波、T2快速自旋回波、脂肪抑制T2快速自旋回波,作弥散加权成像(单次激发回波平面成像序列)检查(b值:0,300s/mm2)。应用弥散加权成像序列及表观扩散系数(ADC)图,测量对照组和病变组骶髂关节骨质的ADC值,测量第一骶椎中央区ADC值,计算rADC值(骶髂关节ADC值/第一骶椎ADC值)。对活动组、非活动组、对照组平均ADC值及平均rADC值进行两两比较。结果活动组(34例)骶髂关节的平均ADC值为0.821×10-3mm2/s,对照组(25例)的平均ADC值为0.589×103mm2/s,稳定组(44例)的平均ADC值为0.622×10-3mm2/s。第一骶椎ADC值对照组活动组、对照级及稳定组分别为0.486×10-3mm2/s、0.423×10-3mm2/s、0.635×10-3mm2/s,统计结果显示,各组两两比较,ADC值的差异均有统计学意义(P<0.05)。对照组、活动组及稳定组rADC值分别为0.959、1.752、1.558。结论 DWI是一个敏感,快速的成像序列,不需要对比剂,成本较低,还能对病变作定量分析,对AS活动性骶髂关节炎价值较高。

Objective：To evaluate the value of diffusion-weighted imaging in detecting active sacroiliitis in patients with ankylosing spondylitis （AS）.Materials and Methods：Based on the modified NEW YORK criteria for AS,78 patients with chronic low back pain were diagnosed AS.They were divided into two groups as active group（n=34） and chronic group（n=44） by rheumatologist according to BASDAI and laboratory parameters.Twenty-five healthy adults composed the control group.FSE-T1WI,FSE-T2WI,FS-FSE-T2WI,and DWI（SS-EPI） （b values：0,300 s/mm2） images were obtained in oblique conronal planar.Apparent diffusion coefficient （ADC） values of all sacroiliac joints（SIJs） were measured on ADC maps.ADC values of normal sacral were also measured.rADC（ADC of SIJ/ADC of sacral） was calculated.Mean （ADC） values and mean rADC values were compared between groups.Results：SWI showed more lesions in diffusion axonal injury and subarachnoid hemorrhage.Due to the image artifacts,SWI was not as good as T1 FLAIR to detected Subdural hemorrhage.SWI showed more hemorrhage lesions in HIE than other sequences.Certain types of vascular malformations with slow flow had been shown to be better visualized with SWI,including cavernous angioma,arterio-venous malformation and sturge-weber syndrome.SWI increased the visibility of tumors and was helpful for depicting hemorrhage and increased vascularity in the neoplasms,which may reflect tumor grade.Conclusion SWI was superior to the conventional sequences for visualizing hemorrhage and vascular structure.SWI can provide useful additional information in the evaluation of various pediatric neurologic conditions.