Inflammation and Infection: Imaging Properties of 18F-FDG–Labeled White Blood Cells Versus 18F-FDG

Journal of Nuclear Medicine

Justin T. Pitman¹  Stephen C. Dragotakes¹  Edward A. Carter¹  Giuliano Mariani¹  Ali A. Bonab¹  Daniela Pellegrino¹ 

关键词: ¹⁸F-FDG–labeled white blood cells;    infection;    inflammation;    biodistribution;    microPET;    phosphorimaging;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

18F-FDG and 18F-FDG–labeled white blood cells (18F-FDG–WBCs) are valuable radiopharmaceuticals for imaging focal sites of inflammation and infection. In the present study, the imaging properties of both radiotracers were compared in sterile and septic inflammation models. Methods: Groups of adult male Sprague–Dawley rats (100–120 g) were injected in the left posterior thigh muscle with saline solution (group 1: controls, n = 15), 0.100 mL of turpentine oil (group 2: sterile inflammation, n = 26), 109 viable Escherichia coli bacteria (group 3: E. coli septic inflammation, n = 29), or 108 viable Pseudomonas aeruginosa bacteria (group 4: P. aeruginosa septic inflammation, n = 25). Twenty-four hours later, the animals were divided into 2 groups: One received 18F-FDG intravenously and the other received human white blood cells (WBCs) labeled in vitro with 18F-FDG injected intravenously. Biodistribution and microPET studies were performed 1 h after radiotracer injection. One hour after injection with cell-associated or free 18F-FDG, phosphorimaging of abscess and contralateral muscle was performed in specimens collected from animals in groups 1, 2, and 3. The region of interest was selected within the abscess wall and values were converted to kBq/g using a 14C calibration standard curve. Thin-layer radiochromatography (TLRC) was performed to study the chemical forms of 18F within the WBCs. Results: Whole-body biodistribution demonstrated a significantly higher uptake ratio of 18F-FDG–WBCs compared with 18F-FDG in all sterile and septic inflammation models (t test: sterile, P = 0.048; E. coli, P = 0.040; P. aeruginosa, P = 0.037). microPET imaging confirmed the greater performance of 18F-FDG–WBCs versus 18F-FDG in the sterile inflammation model and in both E. coli and P. aeruginosa septic models. Phosphorimaging analysis showed higher 18F-FDG–WBC uptake than 18F-FDG in the sterile inflammation and P. aeruginosa septic models and similar tissue uptake in the E. coli septic model. Time course labeling and TLRC of lysed WBCs demonstrated that 18F-FDG was retained as 18F-FDG-6-phosphate inside WBCs for at least 2 h, corresponding to the time frame of analysis. Conclusion: 18F-FDG–WBCs gave better results compared with 18F-FDG in all sterile and septic inflammation models. These data suggest that 18F-FDG–WBC PET may be a useful technique for tracking focal inflammatory lesions in the body.

【 授权许可】

Unknown