Effect of hyoscine butylbromide (HBB) on the uterine corpus: quantitative assessment with T2-weighted (T2W) MRI in healthy volunteers.

Purpose: To investigate effects of hyoscine butylbromide (HBB) on the appearance of three zonal anatomy of the uterine corpus on T2-weighted images (T2WI). Materials and Methods: Sagittal T2WI of the pelvis were acquired before and after intramuscular administration of HBB with interval of 10 minutes in 22 healthy volunteers. By drawing polygonal regions of interest (ROIs), the uterine corpus was delineated into outer rnyometrium (OM), junctional zone (JZ). and endometriurn (EM) in 20 subjects. Areas (mm(2)) and relative signal intensity (rSI) of each layer were compared between pre-HBB and post-HBB administration images by using paired t-tests. Histogram analysis was conducted for the uterine layers and changes were visualized. Results: Areas of OM were significantly increased (P = 0.014) and mean rSI of JZ and OM were significantly increased (P = 0.007 and 0.001, respectively) after administration of HBB. Histogram showed an increase in the number of pixels with higher rSI in the OM, which was considered to be caused by an increase in interstitial fluid and vascular dilatation. EM did not show significant changes. Conclusion: Layer-wise ROI analyses demonstrated changes in the area and rSI in T2WI of the uterus after HBB administration. Histogram analysis contributed to the investigation of signal changes..