The value of vesicant 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in gastric malignancies.
AIM: The value of vesicant 18F-fluorodeoxyglucose positron emission tomography (18F-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 18F-FDG. During the PET study, vesicant was given orally in order to extend the stomach with CO(2) 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 18F-FDG was correlated with the differentiation, size and depth of invasion of the gastric tumours. CONCLUSIONS: 18F-FDG PET is useful for the detection and staging of primary gastric malignancies, and the administration of vesicant may improve the diagnostic confidence.