Value of diffusion weighted imaging and contrast-enhanced MRI in the assessment of the active phase of ankylosing spondylitis / 中国综合临床

ABSTRACT

Objective To investigate the value of diffusion weighted imaging combined with contrast-enhanced MRI(CE-MRI)in activity of sacroiliitis of patients with ankylosing spondylitis(AS).Methods The AS patients diagnosed in Beijing Jishuitan Hospital were selected as the experimental group,and healthy volunteers were selected as the control group.The AS group was divided into the active group and the stable group according to the clinical diagnostic criteria.All subjects were examined with both MRI plain scan and CE-MRI of bilateral sacroiliac joints.ROIs were drawn in the lesion region and the ADC values and signal intensity enhancement rate(△SI)were recorded.△SI and ADC value among the active AS group,chronic group and control group was compared and analyzed.The clinical diagnostic criteria was regarded as the gold standard for the active AS group and the chronic group.The ROC curve was used to evaluate the value of ADC,△SI,ADC, and ADC combined with △SI can detect the efficiency of AS activity.Results Ninety-eight AS patients were enrolled in this study,including 63 cases in the active AS group,35 cases in the chronic AS group,and 23 cases in the control group.The ADC values of the active group,the chronic group and the control group were(1.35 ±0.17)×10-3mm2/s,(1.07±0.20)×10-3mm2/s,(0.36±0.14)×10-3mm2/s,respectively,and ΔSI values were (2.42±0.80)%,(1.28 ± 0.34)% and(0.74 ± 0.22)%.There were significant differences in ΔSI and ADC values among the three groups(F=216.559,56.522.P=0.000).When ADC values were used to assess the activity of AS,the area under the ROC curve was 0.809 and the optimal diagnostic threshold was 1.35×10-3 mm2/s,the sensitivity and specificity of AS activity were 57.1% and 94.3%.When ΔSI values were used,the area under the ROC curve was 0.837 and the sensitivity and specificity were 71.40% and 97.10% with the optimal diagnostic threshold of 1.79%.When ΔSI values were combined with the ADC values,the area was 0.963 and the sensitivity and specificity were 74.6% and 94.3%.Conclusion In assessment of the activity of AS,DWI combined with CE-MRI is most valuable.