The Application Of T2mapping In Evaluating The Activity Of Sacroiliitis In Ankylosing Spondylitis

Objective: To evaluate the value of T2 mapping sequence in diagnosing the activity of sacroiliitis in Ankylosing Spondylitis(AS).Methods: Sixty-two cases of inpatients and outpatients from May 2016 to October 2017 in the Rheumatology and Immunization Department were randomly collected as the experimental group.All patients met the AS diagnostic criteria and exclusion criteria.And 21 cases of normal volunteers as a control group.The experimental group according to Bath ankylosing spondylitis disease activity index(BASDAI score),C-reactive protein(CPR),erythrocyte sedimentation rate(ESR)were divided into active group and stable group.The active group was 42 cases and the stable group was 20 cases.At the same time on the experimental group sacroiliac joint CT spiral scan,and right and left sacroiliac joint lesions were graded.Refer to the T2-IDEAL image to observe the lesion.The T2 values were measured using a region of interest is placed on T2 mapping image of image post-processing workstation.Age,Sacroiliac joint classification,ESR,CRP and BASDAI scores were analyzed by Mann-Whitney U.T2 values of three groups were compared using one-way ANOVA.The receiver operating characteristic curve(ROC)was plotted to obtain the area under the curve(AUC)for T2 values between groups and the diagnostic efficacy was assessed.Results:1.The differences in age,BASDAI score,ESR and CRP between stable group and active group were statistically significant(p <0.05),BASDAI score,ESR and CRP in stable group were lower than those in active group.Activity group ages were lower than the stable group.2.T2 value: The mean T2 values of active group,stable group and control group were 79.79 ± 14.13 ms,57.44 ± 9.39 ms,50.46 ± 5.99 ms.The results showed that the average T2 value in the active group was higher than that in the control group and the stable group(P <0.05),but there was no significant difference between the stable group and the control group(P> 0.05.The T2 value of the experimental group was highly correlated with the BASDAI scores.3.The ROC curve: The optimal cut-off T2 value(AUC,sensitivity,specificity)between the active group and the stable group was 63.90ms(0.893,85.70%,75.00%);The optimal cut-off T2 value(AUC,sensitivity,specificity)between active group and control group was 60.67ms(0.974?88.10%?95.20%);The optimal cut-off T2 value(AUC,sensitivity,specificity)between stable group and control group was 49.91ms(0.743? 85.00%? 61.90%).Conclusion:The mean T2 value of AS activity group was higher than that of the stable group and the control group.The T2 value of the experimental group was highly correlated with the BASDAI score.T2 values have higher diagnostic efficacy.T2 mapping as a non-invasive MR sequence can effectively quantify to evaluate the activity of sacroiliitis in Ankylosing Spondylitis.