Application Of Ultramicroscopic Blood Flow Imaging In The Evaluation Of Synovial Blood Flow In Rheumatoid Arthriti

Objective Exploring the clinical application value of Ultra-microangiography(UMA)in assessing the synovial neovascularization of rheumatoid arthritis(RA)in hand joints,as well as the clinical significance of UMA-sign which reveals surface penetrating blood flow in bone erosion lesions under UMA mode.Methods Power doppler ultrasound(PDUS)and UMA ultrasonography were performed on the wrist,2-3 metacarpophalangeal joints,and 2-3 proximal interphalangeal joints in RA patients who visited Peking Union Medical College from May 2020 to April 2021,and the synovial blood flow signals display and semiquantitative score were recorded respectively.The differences of PDUS-sum and UMA-sum in the above 5 joints was compared by Wilcoxon’s sign rank test.Spearman’s correlation was used to analysis their correlation with the values of CRP,ESR,DAS28(ESR),DAS28(CRP),SDAI,CDAI,SJC,TJC,Pain-VAS,PGA,and EGA,respectively.Subsequently patients were divided into UMA-sign(+)group and UMAsign(-)group based on the presence or absence of perforating blood flow signal signs in bone erosion.The differences in disease activity related indicators between the two groups were compared using Mann Whitney U test,and the difference in remission rate between the two groups was compared by Chi-square test using CDAI≤2.8 as the standard.Results Twenty-nine patients with RA were included in the analysis.The display rates of synovial blood flow in the 5 joints of the dominant hand in PDUS and UMA modes were 21.38%and 27.59%,respectively.There was a statistical difference in the score distribution between PDUS-sum and UMA-sum(Z=3.472,P=0.001),and the semi-quantitative score of synovial blood flow was higher in UMA mode.UMA-sum and PDUS-sum were significantly positively correlated with disease activity-related indicators,and the degree of correlation between UMA-sum was higher than PDUSsum.There was a statistically significant(Z=2.934,P=0.003)between the difference,in which the correlation between PDUS-sum and CRP was the highest(r=0.536,P=0.003),the correlation between UMA-sum and the swollen joint count was the highest(r=0.664,P=0.000).There were 12 patients in the UMA sign(+)group and 17 patients in the UMA sign(-)group,and there was no significant correlation between the sign and age or gender(age:56.0[51.5-59.8]vs 56.0[48.5-64.5],P=0.777;gender:66.7%vs 64.7%,P=0.914).Compared with UMA sign(-)patients,UMA sign(+)group patients showed higher disease activity in laboratory test results,clinical manifestations,disease activity scores,and standardized clinical scores(P<0.05),as well as lower clinical remission rate(remission rate:UMA-sign(+)vs UMA-sign(-)=8.3%vs 47.1%,P=0.026).Conclusion As a novel imaging technology,UMA has more powerful capability in detecting blood vessels in synovial when compared with PDUS,and can more accurately evaluate disease activity in RA when complementary used with clinical indicators.Under UMA mode,the appearance of perforating blood flow in bone erosion in RA patients may indicate higher disease activity and require the attention of clinical physicians.