Assessment of Magnetic Resonance Imaging Neurography and Tractography for Preoperative Mapping of Pelvic Nerves

Study Overview
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Brief Summary
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This project aims at assessing two MRI acquisition methods, neurography and tractography, for the visualization of pelvic nerves. The goal is to optimize both methods and to test them on a pool of volunteers to assess if nerves can be delineated, so as to provide an individualized mapping of nerves to surgeons before an intervention and avoid postoperative complications.

Detailed Description
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Nerves of the autonomic nervous system are frequently damaged during pelvic surgery, and those injuries may lead to postoperative complications like incontinence or impotence. This study aims at developing an imaging protocol providing images where nerves can be visualized and segmented. A simple preoperative MRI exam might yield an individualized mapping of pelvic nerves that would be combined to augmented reality, thereby providing a valuable support to guide surgeons during an intervention by indicating location of the nerves that have to be preserved. Up to now, investigations have been carried out with a 1.5 Tesla (1.5T) MRI system on an animal model (pig). MRI is non irradiant and non invasive imaging modality that proved to be a valuable method to visualize small structures like nerves. Investigations focused on MRI neurography, an anatomical imaging method highlighting nerves, and MRI tractography, a diffusion-tensor-based imaging method allowing reconstruction of nervous fibers. However, the swine model is not ideal due to major differences with human, more particularly the fact that the human pelvis contains a lot of fat unlike the swine pelvis, which is an interesting feature as there is a good contrast between fat and tissue in MRI. Therefore, it is important to perform new investigations in healthy volunteers to refine and assess the MRI acquisitions. Those investigations will be performed with a 3Tesla (3T) system from the same manufacturer, providing the same sequences but a higher field strength which should offer higher signal. There will be no injection of contrast agent. The protocol will use standard sequences from the manufacturer with parameters adjusted for the purposes of the study. The image quality will be scored on a 5-point Likert scale (0 = no possible delineation to 4=nerves are entirely visible).

Official Title
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Assessment of Magnetic Resonance Imaging Neurography and Tractography for Preoperative Mapping of Pelvic Nerves

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Procedure: MRI acquisition - no contrast agent


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Volunteers, male or female, from 18 years old Volunteers able to understand the study and to provide informed consent Volunteers affiliated to the French social security system Exclusion Criteria: Volunteer with contraindications to MRI (implanted device like pace-maker or neurostimulator, ferromagnetic materials, claustrophobia or obesity) Volunteer that already underwent pelvic surgery Volunteer pregnant or breastfeeding Volunteer unable to provide informed consent Volunteer refusing to be informed of any anomaly during an exam Volunteer that already received more than 4500€ of allowance for biomedical testing Volunteer in exclusion period (determined by a previous study or in progress) Volunteer having forfeited their freedom of an administrative or legal obligation Volunteer under guardianship Volunteer carrying a multiresistant bacteria

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MRI acquisition - no contrast agent<br>Volunteers will have an MRI with a 3T clinical system. Installation will be performed according to standard protocols. Different neurography and tractography sequences will be acquired in order to get different contrasts. | Procedure: MRI acquisition - no contrast agent<br>* No surgery. Volunteers will have an MRI with a 3T clinical system. Installation will be performed according to standard protocols. Different neurography and tractography sequences will be acquired in order to get different contrasts.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of image quality to delineate and identify nerves | The assessment of image quality to delineate and identify nerves will be scored on a five-point Likert scale by the operator, and independently reviewed by a radiologist. | At the time of exam | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Image quality at 1.5T and 3T by comparison of signal-to-noise ratios | Assessment of signal-to-noise ratios to compare 1.5T and 3T fields. | At the time of exam | 
| Comparative evaluation score for neurography and tractography methods | Neurography and tractography methods will be scored on a five-point Lickert scale. | Through study completion, an average of 1 year | 
| Acquisition time for neurography and tractography methods | Required acquisition time for neurography and tractography methods will be compared if evaluation scores are equivalent. | At the time of exam | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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MRI, Neurography, Tractography, Pelvic nerves