The Performance In Detecting Subarticular Bone Erosion Of Sacroiliac Joint In Patients With Ankylosing Spondylitis:A Comparison MRI With CT

Objective: To assess the sensitivity and specificity of detecting subarticular bone erosion of sacroiliac(SI)joint in patients with Ankylosing spondylitis(AS)using MRI Multi Echo Gradient echo sequence(3D-MERGE)and Computed Tomography(CT),T1-weighted(T1WI)sequence.Materials and methods: Sixty patients with AS(from the Department and Outpatient Department of Rheumatology in the Affiliated Hospital of North Sichuan Medical College from May 2016 to February 2017)were randomly collected in this study.All patients with AS are checked by CT and MRI.MRI examination sequences include T1 WI,short tau inversion recovery(STIR)and 3D-MERGE.Two experienced adiologists,blinded to clinical data(T1WI、3D-MERGE and CT),independently determined bone erosion at bilateral sacral and iliac sides of the SI joint on CT,T1 WI and 3D-MERGE respectively.χ2 test was used to compare the sensitivity of detecting bone erosion among different diagnostic methods.Results: Of the 120 sacral and 120 iliac articular surfaces from the 60 cases,CT,MRI T1 WI and 3D-MERGE showed the presence of bone erosion in 131,88 and 127 articular surfaces respectively.MRI 3D-MERGE and CT demonstrated similar sensitivity(χ2= 0.13,P = 0.71,P > 0.05),and both were superior to T1WI(χ2 = 12.81,P = 0.00和χ2 = 15.53,P = 0.00).Using CT diagnosis as the gold standard,the sensitivity and specificity of detecting bone erosion for MRI 3D-MERGE and T1 WI sequences were 95.4%,62.6%,and 98.2%,94.5% respectively.Conclusion: MRI 3D-MERGE sequence is associated with zero ionizing radiation,high sensitivity and specificity of displaying the subarticular bone erosion of SI joints in patients with AS.Therefore,To a certain it can be considered an alternative to CT.