Dose effect of dicyclomine on the reduction of peristaltic artifacts on MRI of the abdomen

Background: It has been demonstrated that oral administration of dicyclomin e significantly reduces the noise associated with the movement of the gastr ointestinal tract in abdominal magnetic resonance (MR) images. Our objectiv e was to determine the efficacy and security of two different doses of oral dicyclomine for the reduction of the gastrointestinal noise in abdominal M R imaging. Methods: Forty-eight patients with MR imaging of the upper abdomen were enr olled in a prospective, controlled, randomized, and double-blind study. All patients ingested barium of high density (196 g in 130 mL of tap water, 25 0 w/v) approximately 25 min before the MR examination. Patients were random ly distributed into three groups of 16 patients each: (a) no-drug control g roup, (b) 20 mg of dicyclomine chlorhydrate, and (c) 80 mg of dicyclomine c hlorhydrate. Quantitative image analysis was performed with region-of-inter est measurements of the signal intensity in background air posterior and la teral to the patient and in the liver. Adverse effects were counted at 2 h and 1 day after the MR examination. Results: The liver and incoherent noise signal intensities were not statist ically different among groups. The control group presented a gastrointestin al noise (mean and SD of the air signal intensity) that was statistically s uperior to that of the groups With dicyclomine (p = 0.004 and p = 0.001, re spectively), although significant differences were not observed between the two dicyclomine groups. Although the differences were not significant, adv erse effects were mon frequently associated with the higher doses of dicycl omine. All the adverse effects (most frequently, constipation, diarrhea, an d abdominal pain) were considered minor and did not require treatment. Conclusion: Oral dicyclomine is effective and safe for the reduction of per istaltic artifacts on abdominal MR imaging. The dose of 20 mg presents an e fficacy similar to that of 80 mg, with a probably lower incidence of advers e reactions.