title: Classification of Physiological 18F-fluorodeoxyglucose Uptake in the Large Intestine: a Preliminary Study.
abstract: Varying degrees of physiological uptake of 18F-fluorodeoxyglucose (FDG) are often noted in the large intestine and can be problematic when interpreting positron emission tomography (PET) images. In relation to colorectal tumor detection with FDG PET, we tentatively classified physiological FDG uptake in the large intestine according to its patterns and intensity. Subjects were 144 asymptomatic individuals (109 men, 35 women; mean age 57.5 ± 10.1 years) in our cancer screening program who underwent total colonoscopy within 24 days of FDG PET study and showed no evidence of colonic lesions on colonoscopy. Distinct FDG uptake on FDG PET images was classified into four types: focal, defined as distinctly nodular and visible on at least 4 axial; localized, 2 to 8 cm with SUVmean ≥ 4; diffuse, > 8 cm with SUVmean ≥ 4; and mixed, of more than one type. SUVmeans were examined by placing multiple circular regions of interest of 1 cm in diameter on the axial images. We found 21 distinct FDG uptakes matching our criteria in 20 of 144 subjects (13.9%): focal (n = 4), localized (n = 1), diffuse (n = 14), and mixed (n = 1; focal and diffuse). With regard to colorectal tumor detection, 6 subjects (4.2%) with focal or localized type of uptake were considered at risk of false-positive tumor identification, and 15 subjects (10.4%) with diffuse type of uptake were considered at risk of their tumors being missed at the site of FDG uptake. To confirm the feasibility of our criteria, this classification should be tested with a larger number of subjects.
authors.affiliation: Department of Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. yasuda@is.icc.u-tokai.ac.jp.
authors.forename: Seiei
authors.initials: S
authors.lastname: Yasuda
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Masao
authors.initials: M
authors.lastname: Ono
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Miyatake
authors.forename: Mizuho
authors.initials: M
authors.lastname: Miyauchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kato
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Tanaka
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Ito
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000517:prevention & control; D003951:Diagnostic Errors; D005189:False Positive Reactions; D005240:Feasibility Studies; D005260:Female; D005462:Fluorine Radioisotopes / Q000378:metabolism*; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D007420:Intestine, Large / Q000378:metabolism*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000378:metabolism*; D012306:Risk
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18