Retrospective Review of the Diagnosis and Clinical Impact of Unexpected or Incidental Positive Findings in Positron Emission Tomography (PET) Scans of the Gastrointestinal Tract (GI)

Abstract

Introduction: To investigate incidental findings of the gastrointestinal tract as found on PET scan imaging as ordered for other diagnoses in a south Texas veteran population. A retrospective chart review of these unexpected or “incidental” findings was done to determine if a diagnosis was made and its clinical significance if any. Methods: This is a retrospective study in which we examined a database of veterans who had PET scans ordered for a cancer diagnosis from 2011-2012. Subjects with unexpected findings of hypermetabolic activity (incidental findings) involving the tubular and non-tubular GI tract were analyzed, as well as if any follow-up investigative exams, endoscopic or other further imaging studies that resulted in the finding of a specific diagnosis. Results: Of 818 PET scans over the study period, 180 (22%) showed GI tract incidental findings. Of the 180 records, 36 (20%) had non-tubular findings and 153 (85%) showed tubular findings (some PET scans showed both tubular and non-tubular findings). Of those with tubular findings (153), follow-up exams were performed in 46 (30%). Out of those, endoscopic exams were done in 41 and other imaging done in 6 (one had both). Of the 46 records with follow-up on tubular GI PET findings, a new diagnosis was made in 8 by either modality. In 107, no further studies were done, although recommended, and in 38, further investigative studies did not yield a diagnosis and these were assumed to be false positives. Conclusion: In this retrospective study in a population of south Texas veterans, unexpected or incidental findings of the GI tract were found in 180 of 818 studies. These “incidental” findings, when found in the tubular GI tract resulted in a change in a diagnosis and management in only 8 of patients. These results suggest that unexpected findings in a small number of patients as found on PET scan imaging, can have a significant clinical impact in select patients. Further investigation is warranted in pursuit of a diagnosis by imaging studies or endoscopic exam in this subgroup of patients.