Incidental Colonic Focal Lesions Detected by FDG PET/CT

Abstract

Presence of a focal colonic FDG uptake incidental finding on a PET/CT scan justifies a colonoscopy to detect (pre-)malignant lesions. The fusion of PET and CT images allows an accurate localization of the lesions. PET/CT is a useful tool to differentiate pathologic from physiologic FDG uptake.

Ability of integrated positron emission and computed tomography to detect significant colonic pathology

“…11,13,14 The false-positive rate we found for incidental findings on PET-CT was at the high end of this range but likely reflects our selection process: all patients in our study had colonoscopies after PET-CT, whereas 30%-56% of patients with incidental colonic activity on PET-CT in other studies did not have subsequent colonoscopies. 11,13,14 In our study, because we included only those incidental findings evaluated by colonoscopy within 90 days, our rate of incidental 18 F-FDG colonic activity (0.6%) is lower than reported in earlier series. The 65% PPV of PET-CT to detect clinically significant pathology in our study is comparable to the 64%-67% PPVs reported in previous studies.…”

“…17 Incidental colonic focal 18 F-FDG uptake on PET-CT has been reported in 1.3%-2.7% of patients. 11,13,14 Although subsequent evaluations revealed significant pathology in most of these patients with incidental colonic activity, false-positive rates of 16%-33% have been reported. 11,13,14 The false-positive rate we found for incidental findings on PET-CT was at the high end of this range but likely reflects our selection process: all patients in our study had colonoscopies after PET-CT, whereas 30%-56% of patients with incidental colonic activity on PET-CT in other studies did not have subsequent colonoscopies.…”

“…11,13,14 Although subsequent evaluations revealed significant pathology in most of these patients with incidental colonic activity, false-positive rates of 16%-33% have been reported. 11,13,14 The false-positive rate we found for incidental findings on PET-CT was at the high end of this range but likely reflects our selection process: all patients in our study had colonoscopies after PET-CT, whereas 30%-56% of patients with incidental colonic activity on PET-CT in other studies did not have subsequent colonoscopies. 11,13,14 In our study, because we included only those incidental findings evaluated by colonoscopy within 90 days, our rate of incidental 18 F-FDG colonic activity (0.6%) is lower than reported in earlier series.…”

“…One common site for such incidental activity is the colon. [10][11][12][13] Colonoscopic evaluation of incidental colonic PET activity frequently reveals abnormalities, but no lesion is found in a third of patients in most reports. 11,14 Furthermore, PET-CT does not detect all clinically relevant lesions.…”

“…[10][11][12][13] Colonoscopic evaluation of incidental colonic PET activity frequently reveals abnormalities, but no lesion is found in a third of patients in most reports. 11,14 Furthermore, PET-CT does not detect all clinically relevant lesions. 15,16 Thus, although it has been proposed as a new way of diagnosing and monitoring colonic diseases, PET-CT has a significant falsepositive rate and a poorly defined false-negative rate for colon pathology.…”