Ankylosing Spondylitis:Sacroiliac Joint Activity Assessment By DWI And DCE-MRI And Late-Onset Sacroiliac Joint MRI Characteristics

Objective:To analyze the value of DWI and different quantitative parameters of DCE-MRI in the assessment of the inflammatory activity of the sacroiliac joint in ankylosing spondylitis（AS）.Methods:The data of 42 patients with AS diagnosed clinically by the Department of Rheumatology and Immunology of our hospital.All patients underwent DWI and DCE-MRI of the sacroiliac joint within one week of admission.According to the ASDAS-crp score of clinical disease activity,the patients were divided into the active group（ASDAS-crp≥1.3）and the inactive group（ASDAS-crp<1.3）.There were 24patients in the active group and 18 patients in the inactive group.The differences in the value of ADC and DCE-MRI quantitative parameters(K^trans,K_ep,V_e,V_p)and semi-quantitative parameters(TTP,C_max,Slope_max,AUC)between the two groups were compared.The receiver operating characteristic curve（ROC）was applied to evaluate the efficacy of parameters with statistical differences in differentiating the active group from the inactive group.The correlation between each parameter value and ASDAS-crp score was analyzed.Results:The values of ADC,K^trans,K_ep,V_e,TTP,C_maxand AUC in the active group were higher than those in the inactive group,and the differences were statistically significant（P<0.05）.The differences in V_pand Slope_maxbetween the two groups were not statistically significant（P>0.05）.The area under the ROC curve of the values of ADC,K^trans,K_ep,V_e,TTP,C_maxand AUC in evaluating AS in the active group was 0.889,0.850,0.681,0.888,0.731,0.796,and 0.757,respectively.The sensitivity was 87.50%,91.67%,41.67%,75.00%,66.67%,79.17%,79.17%,and the specificity was 83.33%,66.67%,100.00%,94.44%,94.44%,83.33%,77.78%,respectively.There was a positive correlation between the value of ADC and ASDAS-crp score（r=0.509）.The values of DCE-MRI quantitative parameters V_eand K^transhad strong correlations with ASDAS-crp score（r=0.647,0.646）,which were higher than that between the values of K_ep,TTP,C_max,AUC and ASDAS-crp score.The correlation coefficient was 0.481,0.306,0.464,0.418,respectively.Conclusion:The value of DWI and different quantitative parameters of DCE-MRI can well distinguish the active group and the inactive group of AS,and can be used as significant imaging methods to assess the activity of AS sacroiliac joint lesions.The value of ADC,semi-quantitative parameters（TTP,Cmax,AUC）and quantitative parameters（Ktrans,Kep,Ve）of DCE-MRI are positively correlated with the clinical ASDAS-crp score.Objective: To analyze the MRI features of the sacroiliac joint in late-onset ankylosing spondylitis（LAS）and to compare the differences in the MRI features of the sacroiliac joint between different gender groups in LAS.Methods: From January 2014 to August 2022,70 patients with LAS（LAS group）were hospitalized in the Department of Rheumatology and Immunology of our hospital,and70 patients were diagnosed with adult-onset ankylosing spondylitis（AAS）during the same period（AAS group）.Now for a retrospective analysis of them,the LAS group was further divided into the male group（n=40）and the female group（n=30）according to gender.All patients underwent MRI of the sacroiliac joint within one week of admission and the SPARCC score was recorded.We compared the differences in clinical manifestations,laboratory serological indices and sacroiliac joint MRI features between the LAS group and the AAS group,the male LAS group and the female LAS group.The correlation between clinical disease activity ASDAS-crp score and sacroiliac joint MRI SPARCC score in the LAS group was also analyzed.Results: Compared with the AAS group,the first clinical symptoms of the LAS group were more common in peripheral joint swelling and pain,and the course of the disease was relatively long.The number of female patients increased.The differences were statistically significant（P<0.05）.The positive rate of HLA-B27 in laboratory serological indicators in the LAS group was lower than that in the AAS group.The scores of ESR,CRP and ASDAS-crp in the LAS group were higher than those of the AAS group.The differences were statistically significant（P<0.05）.The sacroiliac joint MRI SPARCC in the LAS group was higher than that of the AAS group.The differences were statistically significant（P<0.05）.The incidences of subcutaneous fat deposition,bone marrow edema and joint space fusion of sacroiliac joint on MRI in the LAS group were higher than those of the AAS group.The differences were statistically significant（P<0.05）.The ASDAS-crp score and the incidence of sacroiliac joint space fusion in the male LAS group were higher than those in the female LAS group.The differences were statistically significant（P<0.05）.There were no statistically significant differences in other clinical indicators（age,course of disease,first symptoms）,laboratory serological indicators（ESR,CRP,HLA-B27）,sacroiliac joint MRI SPARCC and other main features of sacroiliac joint MRI（fat deposition,bone marrow edema,narrowing of joint space）between the LAS groups of different gender（P>0.05）.The MRI SPARCC score of the sacroiliac joint in the LAS group was positively correlated with the ASDAS-crp score（r=0.762）.Conclusion: There are differences between LAS and AAS in clinical first symptoms,disease duration,gender,HLA-B27,ESR,CRP,ASDAS-crp score and sacroiliac joint MRI SPARCC score.Fatty deposits,bone marrow edema and joint space fusion in the sacroiliac joint are more common in LAS than in AAS.The male LAS are more prone to sacroiliac joint space fusion than the female LAS.The sacroiliac joint MRI SPARCC score has value in the assessment of LAS disease activity.