| Part I Comparison of Imaging Value of 6gGa-Citrate PET/CT and 18F-FDG PET/CT in Rat Arthritis ModelsObjective:Rheumatoid arthritis(RA)is a chronic autoimmune disease characterized by systemic,symmetrical,and erosive synovitis.RA is one of the most common disabling diseases in the clinic.The main clinical intervention strategies are early diagnosis and early treatment.The aim of this study is to compare and analyze the diagnostic value of 68Ga-citrate PET/CT and 18F-FDG PET/CT in type II collagen-induced arthritis in rats,and to judge whether 68Ga-citrate PET/CT is superior to 18F-FDG PET/CT in early diagnosis of arthritisMethods:Some CIA models were established.Normal rats were selected as the control group,and 23 days and 40 days were selected as the early and late time points of arthritis,respectively.The semiquantitative analysis of CIA rats was carried out with 68Ga-citrate PET/CT and 18F-FDG PET/CT,and the ratio of the maximum standardized uptake(SUVmax)values in the regions of interest(ROIs)of the hind foot ankle joint and thigh muscle was calculated and statistically analyzed.The distribution of CIA rats in vivo at the 68Ga-citrate 90 min time point was studied,and the ankle tissues were evaluated with hematoxylin and eosin(HE)stainingResults:68Ga-citrate PET/CT is obviously superior to 18F-FDG PET/CT for CIA imaging,and the statistical results show that the difference between the two examination methods is statistically significant(P<0.001).The uptake of these two radiopharmaceuticals showed the same trend in arthritis rats with different scores.The distribution of 68Ga-citrate at 90 min is consistent with the trend shown by 68Ga-citrate PET/CTConclusion:68Ga-citrate PET/CT can reflect the inflammatory activity of affected joints in CIA rats earlier and more sensitively than 18F-FDG PET/CT,and this imaging advantage continues until the later stage of inflammation.Th-erefore,68Ga-citrate PET/CT is worthy of further promotion and application in the clinical diagnosis of RAPart II The Prediction of 68Ga-Citrate PET/CT Imaging for Dihydroartemisinin in the Treatment of Rheumatoid ArthritisObjective:Dihydroartemisinin(DHA)has the effects of anti-inflammation,immune regulation and anti-angiogenesis.The purpose of this study is to use 68Ga-citrate PET/CT non-invasive imaging method to evaluate whether DHA can play a role in the treatment of rheumatoid arthritisMethods:From the establishment of chicken II collagen-induced arthritis(CIA)rat model,20 rats with one-to-one corresponding arthritis index(AI)score were randomly divided into drug group and control group.The drug group was administered orally for 15 days at a dose of 1.5 mL/(Kg·d)(i.e.,containing 20 mg of DHA per 1 ml);the control group was continuously administered with saline at a concentration of 1.5 mL/(Kg·d)for 15 days.68Ga-citrate micro-PET/CT imaging was performed on two groups of model rats on day 0(DO),day 5(D5),day 10(D10),and day 15(D15).After the data reconstruction was completed,the cross-sectional length d(cm)of each ankle joint was measured on the transverse CT,and the SUVmax of the ankle joint and muscle background was measured for statistical analysis.After the completion of the micro-PET/CT collection,the 68Ga-citrate in vivo distribution of the two groups of rats was studied for 90 minutes,and the ankle histology was studied.Results:After 15 days of DHA treatment,the ankle swelling to CIA rats in the drug group was significantly suppressed,while the ankle swelling to arthritis rats in the control group was not significantly suppressed.There was no difference in the time trend of the change in the joint length d(cm)between the drug group and the control group(B=0.017,SE=0.013,P=0.194);there was no significant difference in the average level of joint length d(cm)between the two groups of model rats(B=0.014,SE=0.067,P=0.829);there was no significant difference in the average level of joint length d(cm)of rats at different observation times(B=-0.025,SE=0.017,P=0.146).The time trend of T/NT of the rats in the drug group and the control group was different(B=1.328,SE=0.186,P<0.001);the difference between the average levels of T/NT in the two groups of model rats was statistically significant(B=-1.771,SE=0.747,P=0.018);the differences in the average levels of T/NT in rats at different observation times were statistically significant(B=-1.786,SE=0.237,P<0.001).The correlation coefficient between joint d(cm)and T/NT was statistically significant(rs=0.848,P<0.001).The distribution in vivo showed that the 68Ga-citrate uptake of the ankle joints of the CIA model rats in the drug group was lower than that in the control group,and the 68Ga-citrate uptake of each organ and tissue in the drug group was larger than that in the control group.For ankles with the same score at DO,histological studies showed that the degree of ankle arthritis infiltration in the drug group was lighter than that in the control groupConclusion:The experimental and control groups were used to dynamically monitor the accumulation of 68Ga-citrate in arthritis,indicating that DHA can be used in the treatment of rheumatoid arthritis and can effectively reduce tissue inflammation.At the same time,68Ga-citrate PET/CT has potential application value in the dynamic monitoring of DHA for rheumatoid arthritis. |
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