A Case of 1:1 Correlation Between PET/CT Scan and Endoscopic Findings of Diverticular Disease

Abstract

Diverticulosis is the most common lesion found on routine colonoscopy and its complications impose a significant burden on US healthcare.It effects 70% of those 80y or older in the US and its incidence is expected to increase with the growing aging population.While diverticular disease may be identified on CT scan, colonoscopy is used to define extent of disease.In cases of brisk diverticular bleeding, nuclear medicine bleeding scans can aid in localizing bleeding source for further intervention, such as angiographic embolization or segmental colonic resection.We present an incidental case of subclinical diverticulitis found on PET/CT scan which was confirmed by endoscopic evaluation. A 55-year old African American male presented to the ED with dyspnea and right upper extremity swelling.CXR and CT demonstrated a pulmonary mass and pathology confirmed stage IIb non-small cell lung cancer. He underwent chemotherapeutic treatment and follow-up PET/CT scan was advised. In addition to confirming the presence lung malignancy, PET/CT scan revealed 3cm of intensely avid FDG uptake in the descending colon, concerning for diverticulitis v. neoplasm.The patient denied bleeding symptoms, weight loss, abdominal pain, change in bowel habits, previous colonoscopy or family history of colon cancer.Outpatient colonoscopy identified scattered diverticular disease in the descending colon, correlating exactly with the location of increased FDG activity on PET/CT scan. One month later, repeat PET/CT scan was performed for surveillance.The two foci of intense short segment activity in the descending colon remained unchanged in intense activity. The lesions demonstrated a perfect 1:1 correlation with the diverticular disease found on colonoscopy. We report the first case of 1:1 correlation between PET/CT and endoscopic findings of diverticular disease. The utility of PET/CT has been well described in the detection of malignant lesions, but our case demonstrates the ability of PET/CT to recognize non-cancerous inflammatory conditions. As PET/CT is twice as costly with radiation exposure comparable to CT, this modality should not be considered as a screening tool.PET/CT may have a role in select cases of pan-colonic diverticulosis to identify areas of severe inflammation amenable to segmental resection instead of total abdominal colectomy.Further studies should investigate whether this functional molecular imaging test may be implemented in this manner.