Incidental colonic focal lesions detected by FDG PET/CT.
OBJECTIVE
The aim of this study was to assess the performance of FDG PET/CT for the detection of colonic lesions, especially advanced neoplasms (villous or >10-mm adenomas, carcinomas). Because of 18F FDG accumulation in adenomatous polyps, PET using FDG can detect early premalignant colorectal lesions.


METHODS
FDG PET/CT studies performed for a 1-year period in 1,716 consecutive patients with various malignant diseases, except colorectal cancer, were retrospectively reviewed. PET images obtained 1 hr after FDG injection and non-contrast CT images used for attenuation correction were fused for analysis. Of 45 patients showing intense focal colonic FDG uptake, 20 patients (with 21 foci) underwent a colonoscopic investigation, and, when necessary, polyp resection. The intensity of FDG uptake was quantified using the standardized uptake value (SUV(max)).


RESULTS
The FDG colonic foci were associated with 18 colonoscopic abnormalities in 15 patients, with no colonic abnormality detected in five patients (false-positive [FP] results). Histopathologic findings revealed advanced neoplasms in 13 patients (13 villous adenomas and three carcinomas) and two cases of hyperplastic polyps. A difference in the mean SUV(max) was found between FP and true-positive colonic FDG foci but was not statistically significant (p = 0.14).


CONCLUSIONS
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.
Gutman
Fabrice
F
Department of Nuclear Medicine, Rene Huguenin Cancer Research Center, 35 Rue Dailly, Saint-Cloud, France 92210.
Alberini
Jean-Louis
JL
Wartski
Myriam
M
Vilain
Didier
D
Le Stanc
Elise
E
Sarandi
Farid
F
Corone
Carine
C
Tainturier
Catherine
C
Pecking
Alain Paul
AP
D000236:Adenoma / Q000175:diagnosis / Q000000981:diagnostic imaging; D000368:Aged; D003106:Colon / Q000000981:diagnostic imaging*; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003111:Colonic Polyps / Q000175:diagnosis / Q000000981:diagnostic imaging; D003113:Colonoscopy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18