Extensive FDG uptake and its modification with corticosteroid in a granuloma rat model: an experimental study for differentiating granuloma from tumors
Extensive FDG uptake and its modification with corticosteroid in a granuloma rat model: an experimental study for differentiating granuloma from tumors
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DOI：
10.1007/s00259-007-0529-8
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发表时间：
2007-12-01
影响因子：
9.1
通讯作者：
Tamaki, Nagara
中科院分区：
文献类型：
--
作者：
Zhao, Songji;Kuge, Yuji;Tamaki, Nagara
前言炎性病变中F-18-氟脱氧葡萄糖（FDG）摄取增加，特别是在肉芽肿性炎症（例如，结节病），使得难以区分恶性肿瘤与良性病变，并且是肿瘤学中假阳性FDG-PET发现的主要来源。在这里，我们开发了一个大鼠肉芽肿模型，并检查FDG摄取的肉芽肿。方法将大鼠接种卡介苗（BCG）或同种异体肝癌细胞，分为对照组和预处理组（甲基强的松龙，8mg/kg，肌肉注射）。组在FDG注射后1小时测定组织中的放射性。结果肉芽肿对照组大鼠出现成熟的上皮样细胞肉芽肿形成，大量淋巴细胞浸润，组织学表现与结节病相似。肉芽肿的平均FDG摄取与肝癌相当。泼尼松龙减少上皮样细胞肉芽肿形成和淋巴细胞浸润。泼尼松龙显著降低肉芽肿的FDG摄取水平（对照组的52%），但在肝癌中不降低。结论建立了大鼠肌肉肉芽肿模型，其FDG摄取水平与肿瘤相当。泼尼松龙预处理对肉芽肿FDG摄取的影响大于肿瘤。这些结果表明，BCG诱导的肉芽肿可能是一种有价值的模型，并可能为FDG研究提供生物学基础。
Introduction Increased F-18-fluorodeoxyglucose (FDG) uptake in inflammatory lesions, particularly in granulomatous inflammation (e.g., sarcoidosis), makes it difficult to differentiate malignant tumors from benign lesions and is the main source of false-positive FDG-PET findings in oncology. Here, we developed a rat granuloma model and examined FDG uptake in the granuloma. The effects of corticosteroid on FDG uptake in the granuloma were compared with those in a malignant tumor.Methods Rats were inoculated with Mycobacterium bovis bacillus Calmette-Guerin (BCG) or allogenic hepatoma cells, and subdivided into control and pretreated (methylprednisolone acetate, 8 mg/kg i.m.) groups. Radioactivity in tissues was determined 1 h after the FDG injection. FDG-PET was performed in rats bearing BCG granulomas or tumors before and after prednisolone treatment.Results Mature epithelioid cell granuloma-formation and massive lymphocyte-infiltration were observed in the control group of granuloma, histologically similar to sarcoidosis. The mean FDG uptake in the granuloma was comparable to that in the hepatoma. Prednisolone reduced epithelioid cell granuloma-formation and lymphocyte-infiltration. Prednisolone significantly decreased the level of FDG uptake in the granuloma (52% of control), but not in the hepatoma. The FDG uptake levels in the granulomas and tumors were clearly imaged with PET.Conclusion We developed an intramuscular granuloma rat model that showed a high FDG uptake comparable to that of the tumor. The effect of prednisolone pretreatment on FDG uptake was greater in the granuloma than in the tumor. These results suggest that BCG-induced granuloma may be a valuable model and may provide a biological basis for FDG studies.