目的 分析磁共振成像(MRI)诊断 早期强直性脊柱炎(AS)骶髂关节(SIJ)病 变分级的临床价值。方法 选取2017年4 月至2018年6月我院收治的早期AS患者88 例为研究对象，均行CT及MRI检查，对比 两种检查方法下影像特征及在SIJ病变分 级中的诊断价值。结果 CT检查发现早期 AS患者SIJ关节间隙变窄且模糊，关节面 见骨质破坏，呈锯齿状，多发小囊变，髂 骨侧及关节中、下部受累，Ⅰ-Ⅱ级病变 者MRI可见骨质关节面模糊粗糙、骨髓水 肿、骨质软骨受损，T1WI、T2WI、短时 反转恢复序列(STIR)多为低或等信号， Ⅲ-Ⅳ级患者MRI可见明显炎性病变、骨髓 水肿、骨质软骨受损、滑膜厚度增加、脂 肪沉积，T1WI、T2WI高信号，STIR信号不 均匀或不完整；MRI对AS患者SIJ病变Ⅰ 级、Ⅱ级的检出率高于CT(P＜0.05)，两 种检查方法对0级、Ⅲ级、Ⅳ级的检出率 比较差异无统计学意义(P＞0.05)；MRI检 查对关节面下骨质囊变、关节侵蚀、关节 面增生硬化、腰5骶1关节突病变、软组 织肿胀的检出率均高于CT(P＜0.05)；以 病理结果为准，MRI对早期SIJ病变分级 (0-Ⅱ级)诊断的正确率高于CT，而在晚期 SIJ病变分级(Ⅲ-Ⅳ级)诊断方面，CT、 MRI的正确率比较差异无统计学意义(P＞ 0.05)。结论 MRI在早期AS患者SIJ病变分 级中有较高临床价值，可作为首选检查方 法评估骶髂关节改变、脊柱及其附属结构 的早期改变。

Objective To analyze the clinical value of magnetic resonance imaging (MRI) in the diagnosis oflesion classification of sacroiliac joint (SIJ) in early ankylosing spondylitis. Methods 88patients with early AS in the hospital from April 2017 to June 2018 were chosen in the study. All patients were given CT and MRI examination. The imaging characteristics and the diagnostic value in SIJ lesion classification with the two methods were compared. Results CT examination found that the SIJ space in the patients with early AS was narrow and fuzzy, the joint surface showed destroyed bone in a jagged shape and multiple small cystic lesions, the side of ilium and the middle and lower parts of the joints were involved. MRI showed that there were fuzzy and roughbone joint surface, bone marrow edema and bone cartilagein patients with grade I to II lesions. T1WI, T2WI and short-term inversion recovery sequence (STIR) showed low or equal signals. MRI of patients with grade IIIIV lesions showed obvious inflammatory lesions, bone marrow edema, osteocartilage damage, increased synovial thickness and fat deposition. T1WI and T2WI showed high signal and STIR signal was inhomogenous or incomplete. The detection rates of grade I and II SIJ lesions in AS patients by MRI were higher than CT (P<0.05). There was no significant difference in the detection rate of grade 0, grade III or grade IV lesions between the two examination methods (P>0.05). The rates of bone cystic change under articular surface, joint erosion, articular surface hyperplasia and sclerosis, facet joint lesions at the 5th lumbar segment and the 1st sacral segment and soft tissue swelling detected by MRI were higher thanCT (P<0.05). With pathological results as the standard, the correct rate of MRI diagnosis for early SIJ lesions (grade 0-II) was higher than that of CT while there was no significant difference in the correct rate between CT and MRI in terms of the diagnosis of advanced SIJ lesions (grade III to IV) (P>0.05). Conclusion MRI is of greatclinical value in the classification of SIJ lesions in patients with early AS. It can be used as the first choice to evaluate the changes of sacroiliac joint, the spine and its accessory structures.