Performance of 99mTc-PYP scintigraphy in the diagnosis of hereditary transthyretin cardiac amyloidosis.

OBJECTIVE: Most reported research has primarily investigated wild-type transthyretin cardiac amyloidosis (ATTRwt-CA). However, the application of bone scintigraphy for hereditary transthyretin cardiac amyloidosis (ATTRv-CA) has not been systematically investigated. Therefore, in this study, we aimed to evaluate the diagnostic value of 99mTc-PYP scintigraphy in ATTRv-CA. METHODS: Fifty-four patients were enrolled in a highly suspected cardiac amyloidosis cohort. Transthyretin (TTR) gene characteristics were summarized in the ATTRv-CA group. In 99mTc-PYP scintigraphy, the diagnostic efficiency of the visual score (VGS) and heart-to-contralateral chest (H/CL) ratio were evaluated. Furthermore, the interobserver consistency among the diagnosticians was investigated. RESULTS: Twenty-eight patients were diagnosed with ATTRv-CA with eight genotypes. The Ala97Ser genotype accounts for 46% (n = 13) with a mean age of disease onset, definite diagnosis, and interval of 61.6 ± 1.9, 66.5 ± 1.3, and 4.0 (3.0, 6.2) years, respectively. Their VGS is Grade 3, and their H/CL ratio is higher than that of the non-Ala97Ser group, but no statistical significance exists (mean H/CL: 1.95 ± 0.06 vs. 1.87 ± 0.02, p = 0.844). Additionally, ATTRv-CA patients showed VGS ≥ 2, and mean H/CL ratio of 2.09 ± 0.06. The sensitivity and specificity of VGS were 100% and 65%, respectively. And the interobserver consistency analysis of VGS showed the intraclass correlation coefficient is 0.522. The best cutoff value of H/CL ratio was 1.51 (AUC = 0.996), and the diagnostic consistency of H/CL (bias: 0.018) was high. CONCLUSIONS: Ala97Ser is the most common genotype in ATTRv-CA in our cohort, with characteristics of later onset and rapid progression, but delayed diagnosis and extensive 99mTc-PYP uptake. Overall, ATTRv-CA patients showed moderate-to-extensive myocardial 99mTc-PYP uptake. Additionally, VGS carries subjectivity, low specialty and interobserver consistency. But H/CL exhibit high diagnostic efficacy and interobserver consistency. The H/CL ratio is more useful than VGS.

[IL-10 suppresses inflammatory granuloma uptake of 18F-FDG in rats].

OBJECTIVE: To evaluate the effectiveness of IL-10 in suppressing 18F-FDG uptake in the inflammatory granuloma of SD rats. METHODS: Eight SD rats were killed, and their blood was collected sterily. After centrifugion, the white blood cells were incubated in PRMI 1640 for 3 days. Then each culture flask of white blood cells was divided into two equal parts. To one group was added 0.2 mL IL-10 solution (0.1 mg/mL); to the control was added with 0.2 mL of 0.9% sodium chloride solution. All cells were then incubated for 120 minutes at 37 degree, after which 18F-FDG (1.85 MBq) was added. Sixty minutes later, the cells were washed twice with PBS and the extent of uptake 18F-FDG determined. In vivo, an inflammatory granuloma was produced by hypodermic injection of rats with a mixture of Freund's complete adjuvant, bovine serum albumin and talcum powder. Each rat was maintained for 8 weeks. Imaging of the inflammatory granulomas was performed using the 18F-FDG signal. IL-10 was injected into SD rats at 10 µg/kg of body weight. Sixty minutes later, 7.4 MBq of 18F-FDG were injected, and, after a further 60 minutes, the rats underwent a PET-CT scan. The region of interest (ROI) of the inflammatory granuloma was delineated and the standard uptake value (SUV) calculated. A second PET-CT scan was done without IL-10 on the next day. The granulomatous tissue underwent pathological examination. RESULTS: In the intro test, the with blood cell uptaking ratio of 18F-FDG was (50.3±6.7)% without IL-10, and (34.6±3.5)% with IL-10(t=8.9, P<0.01). IL-10 suppressed the rat white blood cell uptaking 18F-FDG. In the PET-CT scan, the SUV of ROI on inflammatory granuloma was 1.7±0.4 with IL-10 and 2.1±0.3 without IL-10 (t=20.6, P<0.01). IL-10 suppressed the inflammatory granuloma uptaking 18F-FDG. CONCLUSION: IL-10 can suppress the inflammatory granuloma of SD rats uptaking 18F-FDG.