强直性脊柱炎骶髂关节病变的CT诊断价值

目的 探讨CT扫描对强直性脊柱炎（AS）骶髂关节病变的诊断价值及年龄特征对CT表现的影响。方法 收集780例根据临床表现和／或实验室检查疑诊AS，并且骶髂关节的X线及CT资料完整者为研究对象。分别参照X线及CT片对其进行了分级和征象统计，并以＜40岁（第1组513例）和≥40岁（第2组267例）将其分为两组，进行分级及CT表现差异的比较。结果 本组X线诊断为0－Ⅳ级骶髂关节病变的各组中，CT结果与之符合的比率分别为44％、35％、49％、71％和77％。根据CT所示可以分别将56％、29％、33％X线平片诊断正常及Ⅰ、Ⅱ级病变的病例提高1－2个诊断级别。第1组0－Ⅰ组所占比率明显高于第2组，而Ⅱ组比率则远低于第2组。第1组骨性关节面硬化、模糊的发生率明显低于第2组。结论 CT扫描对AS骶髂关节病变的诊断具有重要价值。CT与平片的区别在于细微征象的显示率高，对较早期的病变可以提高诊断等级，同时也有利于治疗析观察。本研究的分组分析结果提示在对骶髂关节的CT片进行分析时亦应将年龄因素导致的退行性表现考虑在内。

Diagnostic value of CT scan for sacroiliac joint in ankylosing spondylitis

Objective　To evaluate the diagnostic value of CT scan for sacroiliac joints in ankylosing spondylitis and the influence of age on CT diagnosis.Methods　All 780 patients with suspected ankylosing spondylitis by clinical manifestations and/or laboratory tests were candidated.Their X-ray and CT scan features were studied and compared.Then they were divided into 2 groups according to their ages:group 1 aged ＜40 years (n＝513) and group 2 aged ≥40 (n＝267).The differences of disease degrees and CT signs between the 2 groups were analysed.Results　Five degrees (0～Ⅳ) of sacroiliac joints were diagnosed by X-ray and CT.Coincidence ratios of X-ray and CT results were 44%,35%,49%,71% and 77%,respectively.There were 56% (0 degree),29% (Ⅰ degree) and 33% (Ⅱ degree) of joints were diagnosed as the normal by X-ray which were raised to 1 and 2 degrees according to CT findings.The ratios of 0～Ⅳ degrees in groups 1 and 2 by CT were 19%,17%,21%,32%,11% and 8%,9%,34%,36%,13%,respectively.Sclerosis and indistinctness of the subchondral cortical plates were found much more frequently in group 2.Conclusion　CT scan is very useful for examining the sacroiliac joints in ankylosing spondylitis,finding out the early sacroilitis and following up because of its higher resolution power for small signs.The influence of age should be considered during analysis of sacroiliac joints.