Pretreatment with diphenoxylate hydrochloride/atropine sulfate (Lomotil) does not decrease physiologic bowel FDG activity on PET/CT scans of the abdomen and pelvis.
OBJECTIVE
Physiologic uptake of 2-[(18)F]-fluoro-2-deoxy-D: -glucose (FDG) by bowel can confound positron emission tomography/computed tomography (PET/CT) assessment for abdominal pathology, particularly within the bowel itself. We wished to determine if oral administration of the antimotility agent, Lomotil (5 mg diphenoxylate hydrochloride/0.05 mg atropine sulfate; G.D. Searle and Company, a division of Pfizer), prior to PET/CT scanning would reduce physiologic uptake of FDG by the small bowel and colon (lower gastrointestinal [GI] tract).


METHODS
Patients undergoing PET/CT scans for lymphoma were enrolled in a prospective, randomized, double-blinded study and received either 10 mL water (control group) or 10 mL Lomotil (experimental group) orally 30-60 min prior to scanning. Scans were reviewed independently by two blinded experienced readers and scored for the degree of FDG activity in the lower GI tract relative to liver activity.


RESULTS
The administration of Lomotil prior to PET/CT scanning did not reduce physiologic FDG activity in the small bowel and colon. In contrast, increased radiotracer uptake by the lower GI tract was observed in the Lomotil group compared to the control group.


CONCLUSIONS
Pretreatment with Lomotil prior to PET/CT scanning confers no benefit toward the reduction of physiologic FDG uptake by the small bowel and colon.
Murphy
Robert
R
Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
Doerger
Kirk M
KM
Nathan
Mark A
MA
Lowe
Val J
VJ
D000005:Abdomen / Q000000981:diagnostic imaging; D000368:Aged; D001285:Atropine / Q000008:administration & dosage*; D004157:Diphenoxylate / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005765:Gastrointestinal Agents / Q000008:administration & dosage*; D006801:Humans; D041741:Lower Gastrointestinal Tract / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D008223:Lymphoma / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011860:Radiography, Abdominal; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D014057:Tomography, X-Ray Computed
D004338:Drug Combinations; D005765:Gastrointestinal Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C002534:atropine sulfate-diphenoxylate hydrochloride drug combination; D004157:Diphenoxylate; D001285:Atropine