磁化传递对比成像和扩散加权成像在中轴型脊柱关节病患者早期骶髂关节炎中的应用

The value of magnetization transfer contrast and DWI in detecting early sacroiliitis in patients with axial spondyloarthropathy

目的:研究磁化传递对比成像(MTC)和扩散加权成像(DWI)在中轴型脊柱关节炎患者早期骶髂关节炎中的应用价值。方法:连续搜集炎性腰背痛并疑为中轴型脊柱关节炎患者84例。所有患者均进行MRI检查,通过添加和不添加预饱和脉冲的三维扰相梯度回波序列,两次扫描获得磁化传递对比成像。同时进行平面回波扩散加权成像,b值选取0和600s/mm2。结果:84例患者中16例诊断为不明原因腰背痛患者(对照组)。68例符合国际脊柱关节炎评估协会制定诊断标准为中轴型脊柱关节炎(SpA组)。SpA患者骶髂关节软骨的磁化传递率(MTR)较对照组明显降低(t=4.02,P<0.05)。SpA患者的骶骨ADC值较对照组明显升高(P<0.05);SpA患者的髂骨ADC值较对照组明显升高(P<0.05)。常规磁共振序列检出中轴型脊柱关节炎的敏感度为63.2%,而骶髂关节软骨磁化传递率在检出中轴型脊柱关节炎的敏感度为75%;骶骨和髂骨骨髓ADC值在检出中轴型脊柱关节炎的敏感度为62.3%和72.1%。结论:磁化传递对比成像和DWI成像能够用于检测早期中轴型脊柱关节炎,对比常规MRI成像序列,磁化传递对比成像和扩散加权成像可作为反映早期骶髂关节炎性改变的半定量测量手段。

Objective：To investigate the value of magnetization transfer contrast（MTC）and diffusion-weighted imaging（DWI）in detecting early sacroiliitis in patients with axial spondyloarthropathy（SpA）.Methods：84consecutive patients with low back pain and being suspected with axial SpA were recruited.All patients underwent MRI examinations.MTC was performed using three dimensional spoiled gradient recalled acquisition sequence（3DSPGR）.DWI was performed using echo-planar sequence with diffusion gradients（b=0and 600s/mm^2）.Results：Of 84 patients,16patients were diagnosed as unspecific low back pain（uLBP）（control group）,and 68 patients were diagnosed as axial SpA according to the criteria of assessment of spondyloarthritis international society（ASAS）.The mean magnetization transfer rate（MTR）of sacroiliac cartilage in axial SpA patients was significantly lower than that in the control group（t=4.02,P〈0.05）.The mean ADC values of bone marrow（or articular cartilage）in axial SpA patients was significantly higher than those in the control group（P〈0.05）for both sacral and iliac sides of sacroiliac joint.The sensitivity of conventional MRI was 63.2%in distinguishing axial SpA from uLBP patients,while the sensitivity of MTR was 75%in distinguishing axial SpA from uLBP patients.The sensitivity of iliac and sacral ADC values was 72.1% and 63.2% respectively in distinguishing axial SpA from uLBP patients.Conclusion：MTC and DWI can improve the detection of the sacroiliitis in the early SpA patients.In addition to the conventional MR sequences,MTC and DWI may serve as a useful tool for the semi-quantitative evaluation of the inflammatory change of cartilage.