Imaging of pelvic floor contractions using MRI.

Magnetic resonance was used to visualize the effect of voluntary pelvic floor contractions on the abdominal structures with particular emphasis in determining the dynamic relationship between the bladder and surrounding organs. The pelvic floor was imaged in 6 asymptomatic female volunteers using MRI viewed in seven coronal and seven sagittal planes. The relative displacement of the bladder resulting from voluntary pelvic floor contraction was measured and the changes from the relaxed to the contracted stage were identified. Measurements from sagittal images show superior bladder wall movement of 3.8 +/- 1.3 mm, posterior of 7.0 +/- 2.8 mm, while maximum movement in the gluteal region was 3.5 +/- 4.0 mm. The results show that voluntary contractions of the pelvic floor measured and visualized using this technique can be identified and displayed using image processing techniques. Anatomical displacement of the bladder in the superior direction is illustrated, demonstrating that pelvic floor contraction provides increased levator muscle support. There is no significant displacement of the anterior aspect of the bladder, while the posterior wall demonstrates maximum movement.