Patterns of FDG Uptake in Stomach on F-18 FDG Positron Emission Tomography: Correlation with Endoscopic Findings

Chae, Min Jeong; Cheon, Gi Jeong; Lee, Sang Woo; Byun, Byung Hyun; Kim, Sungeun; Kim, Yu Chul; Choi, Chang Woon; Lim, Sang Moo

Abstract

PURPOSE
we often find variable degrees of FDG uptake and patterns in stomach, which can make difficult to distinguish physiologic uptake from pathologic uptake on FDG PET. The purpose of this study was to find out the significant findings of stomach on FDG PET. MATERIALS AND METHODS: Thirty-eight patients who underwent both FDG PET and endoscopy within one week from Jun. 2003, to Aug. 2004 were included in this study. We reviewed 38 patients (18 for medical check up, 15 for work up of other malignancies, and 5 for the evaluation of stomach lesion). Their mean age was 56 years old (range: 32~79), men and women were 28 and 10, respectively. Two nuclear physicians evaluated five parameters on FDG PET findings of stomach with a consensus: 1) visual grades 2) maximum SUV (max.SUV) 3) focal 4) diffuse and 5) asymmetric patterns. We correlated the lesions of FDG PET findings of stomach with those of endoscopy. We considered more than equivocal findings on FDG PET as positive. RESULTS: The six of 38 patients were proven as malignant lesions by endoscopic biopsy and others were inflammatory lesions (ulcer in 3, chronic atrophic gastritis in 12, uncommon forms of gastritis in 5), non-inflammatory lesions (n=3), and normal stomach (n=9). By the visual analysis, malignant lesions had higher FDG uptake than the others. The max.SUV of malignant lesions was 7.95 4.83 which was significantly higher than the other benign lesions (2.9 0.69 in ulcer, 3.08 1.2 in chronic atrophic gastritis, 3.2 1.49 in uncommon forms of gastritis (p=0.044) ). In the appearance of stomach on FDG PET, malignant lesions were shown focal (5 of 6) and benign inflammatory lesions were shown diffuse (9 of 20) and asymmetric (14 of 20). Benign lesions and normal stomach were shown variable degrees of uptake and patterns. Some cases of benign inflammatory lesions such as ulcer and gastritis were shown focal and mimicked cancerous lesion (4 of 15). CONCLUSION: Gastric malignant lesions had higher FDG uptake and focal pattern. However, benign inflammatory lesions had moderate degrees of uptake and diffuse and asymmetric patterns rather than focal. It is difficult to differentiate between benign lesions including normal.