Comparison of X-ray, CT and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis / 中华放射学杂志

ABSTRACT

Objective To compare X-ray,CT,and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis (AS).Methods Fifty-three patients with clinical suspected early stage of AS underwent X-ray and MRI scan.MR scan sequences for the sacroiliac joints consisted of T1-weighted,T2-weighted,short time inversion recovery (STIR) and three dimensional balance turbo field echo with water selective excitation (3D-BTFE-WATS) in all patients.In 24 of the patients,fat-saturated contrast-enhanced T1-weighted was used.Twenty-five of 53 patients underwent CT scan.The Chi-square test was used to analyse the uniformity of bone erosions detected by X-ray,CT,and MRI.Results Of the 106 sacroiliac joints in 53 patients,16 sacroiliac joints with bone erosions were detected by X-ray and 63 sacroiliac joints by MRI.Of the 50 sacroiliac joints in 25 patients,26 sacroiliac joints with bone erosions were found by CT.With regard to the detection of bone erosions,there was no difference between CT and MRI (x2 =0.16,P ＞0.05 ) and there was significant difference between CT and X-ray or MRI and X-ray ( x2 =14.44 and 17.36,P ＜ 0.05 ).3D-BTFE-WATS was better than other sequences in detection of bone erosions.Acute inflammatory changes were determined by MRI,which included subchondral bone marrow edema in 32 patients,synovitis in 35 patients,fat depositions in 16 patients,enthesitis in 15 patients,capsulitis in 9 patients,and cartilaginous disruption in 31 patients.Conclusions MRI can detect acute inflammatory changes that can not display by X-ray and CT.Compared with radiography and CT,MRI is more useful in detection of abnormal sacroiliac joint changes in patients with early stage of AS.