  Purpose: Bowel motion is a significant source of artifacts in mouse abdominal
MRI. Fasting and administration of hyoscine butylbromide (BUSC) have been
proposed for bowel motion reduction, but with inconsistent results and limited
efficacy assessments. Here, we evaluate these regimes for mouse abdominal MRI
at high field. Methods: Thirty-two adult C57BL/6J mice were imaged on a 9.4T
scanner with a FLASH sequence, acquired over 90 minutes with ~19s temporal
resolution. During MRI acquisition, eight mice were injected with a low-dose
and eight mice with a high-dose bolus of BUSC (0.5 and 5 mg/kg, respectively).
Eight mice were food deprived for 4.5-6.5h before MRI and another group of 8
mice was injected with saline during MRI acquisition. Two expert readers
reviewed the images and classified bowel motion, and quantitative voxel-wise
analyses were performed for identification of moving regions. After defining
the most effective protocol, high-resolution T2-weighted and diffusion-weighted
images were acquired from four mice. Results: High-dose BUSC was the most
effective protocol for bowel motion reduction, for up to 45 minutes. Fasting
and saline protocols were not effective in suppressing bowel motion.
High-resolution abdominal MRI clearly demonstrated improved image quality and
ADC quantification with the high-dose BUSC protocol. Conclusion: Our data show
that BUSC administration is advantageous for abdominal MRI in the mouse.
Specifically, it endows significant bowel motion reduction, with relatively
short onset timings after injection (~8.5 minutes) and relatively long duration
of the effect (~45 minutes). These features improve the quality of
high-resolution images of the mouse abdomen.
