Endoscopic F-18 FDG detection in esophageal dysplasia: Initial clinical results

659 Objectives: To demonstrate that F-18 FDG can be used to detect and differentiate dysplasia and malignancy in Barrett9s esophagus utilizing a beta-sensitive probe. Methods: After a PET scan, patients with esophageal cancer underwent endoscopic evaluation, with multiple biopsies from normal and abnormal appearing esophageal tissue. Activity in samples was measured with both a PicoCount coinidence counter and a beta probe (IntraMedical Imaging, LLC). Counts are decay-corrected and used to calculate counts/minute/mg of tissue for each sample. Biopsies were classified blindly by an experienced esophageal histopathologist (WMW) as normal squamous esophageal mucosa, premalignant (intestinal metaplasia (IM) or dysplasia) or invasive cancer. Results are normalized using the normal squamous esophageal cpm/mg. Decay-corrected cpm/mg as measured by the PicoCount and the beta probe are correlated and compared with histology. Results: 7 patients were studied, with 8-14 esophageal biopsies per patient. 3 patients (1 cancer, 2 dysplasias) with negative PET scans had evidence of elevated FDG activity in their abnormal biopsies as found by the beta probe and coincidence counter. In the first PEt-negative patient we found 4.85 tumor:normal ratio. The other two patients showed premalignant to normal countrate ratios of 1.7 and 1.9. Overall the mean and standard deviation of ratios of dysplasia to normal countrates were 1.7 +/- 0.8. The mean and standard deviation of ratios of cancer to normal tissue count rates were 2.5 +/-1.2. There was also a strong correlation (r = 0.9) between FDG expression as measured by the PicoCount and the beta probe. Conclusions: Our data demonstrates a differential expression of 18-FDG levels between normal, dysplastic, and invasive esophageal cancer. The beta probe correctly identified abnormal tissue in 3 patients 3 patients with positive histology but negative PET scans. Finally, the strong correlation between between FDG uptake and presence of abnormal tissue suggests the feasibility of endoscopic positron emission molecular imaging for diagnosis and differentiation of esophageal dysplasia and cancer.