Characterization of Uptake of 2-Deoxy-2-[ 18F]Fluoro-D-Glucose by Fungal-Associated Inflammation : The Differential Uptake Ratio for Blastomyces- Associated Lesions is as High as for Lymphoma and Higher than for Turpentine Abscesses in Experimentally Induced Lesions in Rats

Abstract

Purpose: The objective of this investigation was to determine the biologic basis and the significance of uptake of 2-deoxy-2-[ 18F]fluoro-D-glucose (FDG) using experimentally created fungal lesions in rats. Procedures: Uptake of FDG by experimentally induced Blastomyces granulomas was compared with uptake by turpentine abscesses (Group 1) and by lymphomas (Group 2) using the differential uptake ratio (DUR) measured one hour after administration of 2 mCi FDG intravenously. Frozen tissue sections of Blastomyces lesions and turpentine abscesses were placed in contact with radiographic film for macroautoradiography. Results: In rats in Group 1, the median (range) DUR for the Blastomyces granulomas was 1.9 (1.1–2.6) and was significantly higher than the DUR for turpentine abscesses 0.9 (0.6–1.4) and muscle 0.2 (0.1–0.5; P < 0.001). In Group 2, the median (range) DUR for the Blastomyces granulomas, lymphomas, and muscle from the rats in Group 2 were 1.8 (1.2–3.4), 1.9 (1.0–4.0), and 0.2 (0.1–0.3), respectively. There was no significant difference between the DUR of Blastomyces granulomas and lymphomas. Macroautoradiographs of the Blastomyces granulomas revealed intense uptake of FDG in the region occupied by the yeast organisms and the granulomatous inflammation. Conclusions: Blastomyces granulomas typically have high uptake of FDG associated with the region composed of the granulomatous inflammatory reaction and Blastomyces yeast organisms. (Mol Imag Biol 2002;4:193–200)