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

Abstract

Background: It has been demonstrated that oral administration of dicyclomine significantly reduces the noise associated with the movement of the gastrointestinal tract in abdominal magnetic resonance (MR) images. Our objective was to determine the efficacy and security of two different doses of oral dicyclomine for the reduction of the gastrointestinal noise in abdominal MR imaging.

Methods: Forty-eight patients with MR imaging of the upper abdomen were enrolled in a prospective, controlled, randomized, and double-blind study. All patients ingested barium of high density (196 g in 130 mL of tap water, 250 w/v) approximately 25 min before the MR examination. Patients were randomly distributed into three groups of 16 patients each: (a) no-drug control group, (b) 20 mg of dicyclomine chlorhydrate, and (c) 80 mg of dicyclomine chlorhydrate. Quantitative image analysis was performed with region-of-interest measurements of the signal intensity in background air posterior and lateral 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 statistically different among groups. The control group presented a gastrointestinal noise (mean and SD of the air signal intensity) that was statistically superior to that of the groups with dicyclomine (p= 0.004 and p= 0.004, respectively), although significant differences were not observed between the two dicyclomine groups. Although the differences were not significant, adverse effects were more frequently associated with the higher doses of dicyclomine. All the adverse effects (most frequently, constipation, diarrhea, and abdominal pain) were considered minor and did not require treatment.

Conclusion: Oral dicyclomine is effective and safe for the reduction of peristaltic artifacts on abdominal MR imaging. The dose of 20 mg presents an efficacy similar to that of 80 mg, with a probably lower incidence of adverse reactions.