Objective To explore the magnetic resonance(MR)imaging characteristics of joint damage caused by Chikungunya virus(CHIKV)and its correlation with pain severity,and analyze the value of T2-Mapping in asse-ssing the severity and prognosis of such damage.Methods A multicenter retrospective study design was adopted,and patients with CHIKV infection accompanied by joint pain were included in analysis.Multi-joint MR scans were performed to assess joint effusion,synovial thickening,bone marrow edema,and cartilage damage.T2-Mapping values were measured.Pain severity was assessed using the Visual Analog Scale(VAS),and imaging findings were independently assessed by two radiologists.Results A total of 131 patients were included in the study.The inci-dence of joint cavity and/or synovial sac effusion was the highest(77.1％,n=101),with knee and ankle joint effu-sion accounting for 81.2％(severe,mild-moderate were 17 and 65 cases,respectively),other joint effusion were mild.78 cases had synovial thickening(14 and 64 were severe and mild-moderate cases,respectively),27 cases had tenosynovitis,21 cases had bone marrow edema(primarily in the knee and ankle joints).19 cases had cartilage damage,114 cases presented muscle soft tissue edema(17 and 97 were severe and mild-moderate cases,respective-ly),28 cases had Kager's fat pad edema.Patients with elevated T2-Mapping values exhibited more pronounced chronic joint pain,with T2-Mapping values in the cartilage damage site increasing by 40％-60％compared with normal cartilage site(19 cases in total).The T2-Mapping value for severely damaged soft tissue was(52.3+6.7)ms,while for mildly to moderately damaged soft tissue was(42.3±5.2)ms,both significantly higher than normal refe-rence values(＜35 ms,both P＜0.05).Among 17 patients with severe soft tissue damage,12 experienced persistent pain for over one month,with statistically significant differences in T2 values compared with those with mild-mode-rate damage(P＜0.05).This further suggested that the degree of elevation in T2-Mapping values was closely related to the duration of pain and the severity of damage.After one-month follow-up,103 patients had pain relief.Among the 28 patients with ongoing pain,17 developed into subacute bone joint pain.Bone marrow edema(81.0％),ele-vation of T2-Mapping value of cartilage(89.5％),and severe synovial thickening(71.4％)were high-risk MR manifestations of subacute bone joint pain.The incidences of subacute joint cavity/sac effusion and subacute tenosy-novitis were 3.0％and 7.4％,respectively.Conclusion MR can clearly display the inflammatory and structural changes in CHIKV joint damage,and T2-Mapping values may serve as a potential imaging measurement parameter for assessing severity and prognosis of damage.

Objective To explore the magnetic resonance(MR)imaging characteristics of joint damage caused by Chikungunya virus(CHIKV)and its correlation with pain severity,and analyze the value of T2-Mapping in asse-ssing the severity and prognosis of such damage.Methods A multicenter retrospective study design was adopted,and patients with CHIKV infection accompanied by joint pain were included in analysis.Multi-joint MR scans were performed to assess joint effusion,synovial thickening,bone marrow edema,and cartilage damage.T2-Mapping values were measured.Pain severity was assessed using the Visual Analog Scale(VAS),and imaging findings were independently assessed by two radiologists.Results A total of 131 patients were included in the study.The inci-dence of joint cavity and/or synovial sac effusion was the highest(77.1％,n=101),with knee and ankle joint effu-sion accounting for 81.2％(severe,mild-moderate were 17 and 65 cases,respectively),other joint effusion were mild.78 cases had synovial thickening(14 and 64 were severe and mild-moderate cases,respectively),27 cases had tenosynovitis,21 cases had bone marrow edema(primarily in the knee and ankle joints).19 cases had cartilage damage,114 cases presented muscle soft tissue edema(17 and 97 were severe and mild-moderate cases,respective-ly),28 cases had Kager's fat pad edema.Patients with elevated T2-Mapping values exhibited more pronounced chronic joint pain,with T2-Mapping values in the cartilage damage site increasing by 40％-60％compared with normal cartilage site(19 cases in total).The T2-Mapping value for severely damaged soft tissue was(52.3+6.7)ms,while for mildly to moderately damaged soft tissue was(42.3±5.2)ms,both significantly higher than normal refe-rence values(＜35 ms,both P＜0.05).Among 17 patients with severe soft tissue damage,12 experienced persistent pain for over one month,with statistically significant differences in T2 values compared with those with mild-mode-rate damage(P＜0.05).This further suggested that the degree of elevation in T2-Mapping values was closely related to the duration of pain and the severity of damage.After one-month follow-up,103 patients had pain relief.Among the 28 patients with ongoing pain,17 developed into subacute bone joint pain.Bone marrow edema(81.0％),ele-vation of T2-Mapping value of cartilage(89.5％),and severe synovial thickening(71.4％)were high-risk MR manifestations of subacute bone joint pain.The incidences of subacute joint cavity/sac effusion and subacute tenosy-novitis were 3.0％and 7.4％,respectively.Conclusion MR can clearly display the inflammatory and structural changes in CHIKV joint damage,and T2-Mapping values may serve as a potential imaging measurement parameter for assessing severity and prognosis of damage.