Assessment of MRI Tractography for Pelvic Floor Sphincter Analysis

Urinary and faecal incontinences are psychologically difficult to live with. These disorders generally come from a dysfunction of the pelvic floor muscles, and more particularly the sphincters: the urethral sphincter at the level of the urinary tract, and the anal sphincter at the level of the defecatory apparatus. The causes leading to urinary or faecal incontinence are multiple. They may be related to age or weight, or to accidental trauma, obstetric or iatrogenic. On this last point, the incidence of surgical interventions on the bladder collar and on the anal canal on the prevalence of incontinences can be underlined. In case of dysfunction, the sphincters can be scanned by imaging, including MRI, to assess the thickness or detect the presence of scars. The current MRI examinations in clinical routine are not capable to characterize the complex architecture of these muscles. MRI tractography, mainly known as a tool for visualisation and characterisation of white matter fibers in the brain via the acquisition of DTI (Diffusion Tensor Imaging) sequences, could be an interesting tool to visualize in 3D the structure of pelvic sphincters and their lesions. It may thereby establish the link with observed dysfunctions, thus potentially providing a complement to the urological and proctographic examinations already carried out. Some studies have already shown that MRI is an ideal method for visualizing pelvic floor muscle fibers in women. As far as it is known, there are no studies in the literature on pelvic sphincter tractography. The objective is, first, to define from this initial study the sensitivity of the method for the visualization of the pelvic sphincters architecture regardless of the gender. In a second time, it will give a description of normal and abnormal (pathological cases) tractography, as well as a descriptive post-surgery. The results found in each of these situations can be compared in order to evaluate the sensitivity and contribution of MRI tractography for the diagnosis of pelvic sphincter dysfunctions and their management, as well as to evaluate the impact of surgery. The other interest of this study is the inclusion of both patients consulting for a simple diagnosis and those coming for a pre- and post-operative examination. This will allow the assessment of the information provided by pelvic sphincters tractography on a panel of various and frequently encountered situations in clinical routine at the IHU.