Frank Marinus Zijta MD, Presenter: Nothing to Disclose

Marielle Lakeman, Abstract Co-Author: Nothing to Disclose

Martijn Froeling, Abstract Co-Author: Nothing to Disclose

Jan Paul Roovers, Abstract Co-Author: Nothing to Disclose

Aart N Nederveen PhD, Abstract Co-Author: Nothing to Disclose

Jaap Stoker MD, PhD, Abstract Co-Author: Nothing to Disclose

To prospectively explore the potential clinical application of diffusion tensor imaging (DTI) and tractography in the evaluation of the female pelvic floor. 

2D diffusion-weighted spin-echo echo-planar imaging (SP-EPI) of the pelvic floor was performed in 28 women:10 patients with pelvic organ prolapse, 9 age-matched controls and 9 nulliparous women. Offline fiber tractography of the principal pelvic structures using diffusion tensor images was performed by two blinded observers. Quality of the tracking results was assessed in consensus. From agreed tracking results DTI parameters (mean diffusivity(MD), fractional anisotropy(FA)) were calculated. Inter-rater agreement for quality assessment was assessed using prevalence- and bias-adjusted kappa(κ) statistics. Mean values for DTI parameters were compared among the three groups using One way ANOVA with bonferoni post hoc test. 

Good overall inter-rater agreement was found for the anatomical visualization (κ=0.67). Fiber tractography resulted in a clear anatomical representation of the following structures:(19/56) pubovisceral -,(7/56) puborectal -, (0/56) illiococcygeal -,(15/56) superficial transverse perineal -,(30/56) ischiocavernosus - and (12/28) bulbospongiosus muscle and (8/28) urethral sphincter. No perceptible differences were found in per-group distributions. Three structures (anal sphincter complex (AS), perineal body (PB), obturator internus (OI)) were consistently identified in all 28 patients (κ =0.89) and were quantitatively compared. No significant differences in MD and FA was observed for AS and PB between groups. Mean(SD) FA values for AS were 0.22±0.03 to 0.25±0.03 for prolapse patients and nulliparas, respectively. Significant difference in mean FA was found in the OI muscle between the prolapse group and nulliparas 0.27±0.05 and 0.22±0.03(p=0.015).     

DTI permits a three-dimensional visualization of in-vivo pelvic floor anatomy, with consistent visualization of the anal sphincter complex and perineal body. Currently, fiber tractography of the pelvic support is limited by spatial resolution, complex anatomical architecture and per-subject variation in tissue characteristics. 

DTI might provide insights into pelvic floor dysfunction which are not appreciated on conventional MRI. This might include differences in muscle fibre direction and muscle integrity.

Zijta, F, Lakeman, M, Froeling, M, Roovers, J, Nederveen, A, Stoker, J, Evaluation of the Pelvic Floor Using 3.0 Tesla in Vivo Diffusion Tensor Imaging (DTI) and Fiber Tractography: Initial Experience in Pelvic Floor Disorders.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015982.html