RT Journal Article SR Electronic T1 PET/CT Detection of Unexpected Gastrointestinal Foci of 18F-FDG Uptake: Incidence, Localization Patterns, and Clinical Significance JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 758 OP 762 VO 46 IS 5 A1 Ora Israel A1 Nikolay Yefremov A1 Rachel Bar-Shalom A1 Olga Kagana A1 Alex Frenkel A1 Zohar Keidar A1 Doron Fischer YR 2005 UL http://jnm.snmjournals.org/content/46/5/758.abstract AB Precise PET/CT localization of focal 18F-FDG uptake in the gastrointestinal tract (GIT) may exclude malignancy in sites of physiologic activity but may also induce false-negative reports for malignant or premalignant lesions. The purpose of the present study was to retrospectively evaluate the nature and significance of unexpected focal 18F-FDG uptake localized by PET/CT within the GIT. Methods: The files of 4,390 patients referred for 18F-FDG PET/CT were retrospectively reviewed. The incidence of studies showing unexpected focal uptake of 18F-FDG localized by PET/CT to the GIT was determined. The position of these foci along the GIT and their intensity were recorded. The etiology of the findings was confirmed histologically or by long-term follow-up. Results: Unexpected focal 18F-FDG uptake in the GIT was found in 58 patients (1.3%). Follow-up data were available for 34 of these patients, including 4 with sites in the stomach, 2 in the small bowel, and 28 in the colon. GIT-related disease was confirmed in 24 patients (71%). There were 11 malignant tumors, 9 premalignant lesions, and 4 benign processes including 2 benign polyps, 1 case of active gastritis, and 1 abscess of the sigmoid. Ten patients (29%) had no further evidence of GIT abnormality, and the suggestive sites were considered to be physiologic uptake. Maximal standardized uptake value was 17.3 ± 10.2 in malignant lesions, 14.0 ± 10.5 in premalignant lesions, 18.0 ± 12.1 in benign lesions, and 11.1 ± 7.4 in foci of physiologic 18F-FDG uptake in the GIT, with no statistically significant difference among the 4 subgroups. Conclusion: Incidental focal 18F-FDG uptake localized by PET/CT within the GIT is of clinical significance in most patients. These findings should be followed up with appropriate invasive procedures guided by hybrid imaging results.