Feasibility of diffusion tensor imaging (DTI) with fibre tractography of the normal female pelvic floor

To prospectively determine the feasibility of diffusion tensor imaging (DTI) with fibre tractography as a tool for the three-dimensional (3D) visualisation of normal pelvic floor anatomy.

Five young female nulliparous subjects (mean age 28 +/- 3 years) underwent DTI at 3.0T. Two-dimensional diffusion-weighted axial spin-echo echo-planar (SP-EPI) pulse sequence of the pelvic floor was performed, with additional T2-TSE multiplanar sequences for anatomical reference. Fibre tractography for visualisation of predefined pelvic floor and pelvic wall muscles was performed offline by two observers, applying a consensus method. Three eigenvalues (lambda 1, lambda 2, lambda 3), fractional anisotropy (FA) and mean diffusivity (MD) were calculated from the fibre trajectories.

In all subjects fibre tractography resulted in a satisfactory anatomical representation of the pubovisceral muscle, perineal body, anal - and urethral sphincter complex and internal obturator muscle. Mean FA values ranged from 0.23 +/- 0.02 to 0.30 +/- 0.04, MD values from 1.30 +/- 0.08 to 1.73 +/- 0.12 x 10(-)A(3)aEuro parts per thousand mmA(2)/s. Muscular structures in the superficial layer of the pelvic floor could not be satisfactorily identified.

This study demonstrates the feasibility of visualising the complex three-dimensional pelvic floor architecture using 3T-DTI with fibre tractography. DTI of the deep female pelvic floor may provide new insights into pelvic floor disorders.