The value of vesicant 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in gastric malignancies

Aim The value of vesicant F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG PET) in the detection and staging of primary gastric malignancies was studied prospectively. Methods Thirty-eight patients with suspected gastric tumour were imaged with three-dimensional PET after the injection of F-18-FDG. During the PET study, vesicant was given orally in order to extend the stomach with CO2 gas. Surgical operation (n=31) or gastric endoscopy with biopsy (n=7) was undertaken 3-26 days after the PET study. The PET results were compared with clinical (computed tomography/magnetic resonance imaging/ultrasound), surgical and histological staging. Results PET correctly diagnosed 83.3% of primary malignant (25/30) and benign (7/8) lesions, and corrected 11 clinically and five surgically mis-staged cases. Five primaries were false-negatives in quantitative analysis, but qualitative PET readings revealed positive lymph nodes, thereby providing a correct diagnosis in two of the five. PET misdiagnosed seven N1, one N2 and one false-positive case. The focal uptake of F-18-FDG was correlated with the differentiation, size and depth of invasion of the gastric tumours. Conclusions F-18-FDG PET is useful for the detection and staging of primary gastric malignancies, and the administration of vesicant may improve the diagnostic confidence. (C) 2004 Lippincott Williams Wilkins.