| Part 1 MRI sequences comparison study for displaying sacroiliac joint cartilage Objective: To investigate whether the 3D-MEDIC-WE sequences could show the SIJ cartilage clearly,and further to validate the value of the 3D-MEDIC-WE sequences in diagnosing cartilage lesions of sacroiliitis.Methods: A total of 60 patients with typical clinical symptoms of AS were collected,and20 healthy volunteers were enrolled into the control group.And four oblique-coronal MRI sequences,including T1WI/T2WI-TSE,TIRM-T2 WI and 3D-MEDIC-WE were performed.SIJ cartilage were observed to make subjective assessment and different imaging sequences were compared.The total thickness of SIJ cartilage,the cartilage of iliac and sacral sides in the control group were measured respectively.According to whether the edge of the cartilage is clear and so on,we established 5 score standard(0~4points).The grading of SIJ cartilage were assessed from the TIRM-T2 WI and3D-MEDIC-WE sequences respectively.Results: T1 WI,T2WI couldn't display SIJ cartilage;SIJ cartilage showed relatively high signal,and the boundary is not clear with the surrounding bone in TIRM-T2 WI sequence.3D-MEDIC-WE sequence can clearly show the joint cartilage,and distinguish the sacral,iliac cartilage and the gap between them.The SIJ cartilage was(2.70±0.41)mm,cartilage of sacrum(1.21±0.22)mm was thicker than that of ilium's(0.72±0.31)mm,and there was significant difference(t=10.90,P<0.01).The sacroiliac joint cartilage of patients showed homogeneous signal,smooth edges(20 sides);irregular margin(19 sides);rough edge(50 sides);irregular thickening or narrow,twisting,serrated edges(27 sides);joint space narrowing or cartilage disappeared,not shown(4 sides).Scores of cartilage erosion in 3D-MEDIC-WE sequence were statisticly higher than that in TIRM-T2 WI sequences(c2=176.644,P<0.01).Conclusion: 3D-MEDIC-WE sequence can identify SIJ cartilage and show SIJ cartilage lesions more clearly than T1 WI,T2WI,TIRM-T2 WI.Part 2 Application of diffusion-weighted imaging and dynamic contrast-enhanced MRI in the detection of acute sacroiliitis.Objective: To investigate the value of diffusion-weighted imaging(DWI)and dynamiccontrast-enhanced MRI(DCE-MRI)in the detection of acute sacroiliitis.Methods: A total of 42 suspicious patients with typical clinical symptoms of AS were collected,and 18 healthy volunteers were enrolled into the control group.Bilateral SIJs were examined by plain MR scan,DCE-MRI and DWI.According to whether the marrow signal became higher in TIRM-T2 WI sequence,cases were divided into acute inflammation group(AIG)and non-acute inflammation group(NAIG).The SPARCC score were measured in the AIG.Time-intensity curve(TIC)was obtained from DCE-MRI,and all groups were typed according to TIC.The factor of enhancement(Fenh),slope of enhancement(Senh)and the ADC value were then calculated compared with the control group.Correlative analysis was performed among SPARCC score,ADC value and Fenh in the AIG.Results: TIRM-T2WI/DWI/DCE-MRI showed no significant difference in the detection of acute sacroiliitis(c2=2.06,P>0.05).The SPARCC score in the AIG were 21.06±3.15.The mean ADC values,Fenh,Senh in the AIG were higher than the NAIG and the control group.There were significant difference among the three groups(F=381.591,62.080,11.097;P<0.01).The three parameters above-mentioned were similar between the AIG and control group(P>0.05).All TIC were influent in the AIG,13 of which(72.22%)were fast rising platform type,5 of which(27.78%)were going fast rising.All in the NAIG and control group were fast rising and slow drop.The Spearman correlation analysis showed that in the AIG SPARCC score and ADC values,SPARCC score and Fenh,ADC values and Fenh were positively correlated(r=0.874,0.673,0.723;P<0.05).Conclusion: DWI and DCE-MRI are sensitive to show SIJ active inflammation.The ADC values,Fenh and Senh can be effectively used to quantify inflammatory areas in SIJ.DWI and DCE-MRI have a significant clinical value in detecting active inflammation in the SIS. |
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