强直性脊柱炎骨盆骨髓脂肪沉积的磁共振成像分析

Magnetic resonance imaging for pelvic bone marrow fat deposition in patients with ankylosing spondylitis

目的：通过分析强直性脊柱炎（AS ）患者骨盆骨髓脂肪沉积（BMFD）的MRI表现及其分布特点，评估骨盆BMFD对AS的诊断价值。方法选取88例患者行骨盆MRI检查，其中44例经临床确诊的AS患者作为病例组，44例经临床确诊的非AS患者为对照组。分别比较两组患者双侧骶髂关节及髋臼BMFD的发生率、病例组骨盆关节与非关节部位BMFD的分布特点。病例组双侧骶髂关节炎及髋关节炎不同阶段BMFD的发生率有无差异。结果病例组双侧骶髂关节、髋臼BMFD的发生率显著高于对照组（P＆lt;0.01）；关节面下松质骨BMFD的发生率明显高于非关节部位（P＆lt;0.01）；骶髂关节早期BMFD的发生率为40.0%~45.9%，晚期病变BMFD的发生率为58.3%~73.1%，晚期明显高于早期（P＆lt;0.01）；髋臼各期病变之间BMFD发生率的差异无统计学意义（P＆gt;0.01）。结论骨盆MRI显示BMFD在AS患者中发生率较高，主要分布于关节面下，可发生于AS病变的全过程，提示BMFD是AS骨髓病理改变的重要征象，很有可能成为早期诊断AS的重要依据。

Objective To evaluate the diagnostic value of pelvis bone marrow fat depositions （BMFD） displayed by magnetic resonance imaging （MRI） in patients with ankylosing spondylitis （AS）. Methods Eighty-eight subjects undergoing pelvic MRI examinations were enrolled in this study, including 44 with clinically confirmed AS （39 male and 5 female patients with a mean age of 26.41＆#177;8.09 years） and 44 control subjects without AS （37 male and 7 female subjects with a mean age of 29.32＆#177;7.31 years）. The incidence of BMFD in the bilateral sacroiliac （SI） joints and acetabulums were compared between the two groups. The distribution features of BMFD of the periarticular cancellous bone marrow in the pelvis and in other regions of the pelvis were analyzed for the AS patients, and the incidence of BMFD was determined in different stages of sacroiliitis and hip arthritis. Results The incidence of BMFD in the SI joints and acetabulums was significantly higher in the AS patients than in the control subjects （P＆lt;0.01）; The incidence of BMFD was significantly higher in the periarticular cancellous bone marrow than in the other positions of pelvis （P＆lt;0.01）. The incidence of BMFD ranged from 40.0% to 45.9% in early stages of sacroiliitis, significantly lower than the incidence in later stages （58.3%-73.1%, P＆lt;0.01）; the incidence showed no difference between different stages of hip arthritis （P＆gt;0.01）. Conclusions AS patients have a higher incidence of BMFD in the pelvis than control subjects. BMFD is distributed mainly under the articular surface, seen throughout the stages of AS, indicating that BMFD is an important pathological change of the bone marrow in AS to potentially allow early diagnosis of AS.