Cranial Nerves Tractography

Study Overview
=================
Brief Summary
-----------------
Introduction: The skull base tumors surgery remains a challenge since numerous cranial nerves or vessels closely surround them. Recently, diffusion tensor imaging has developed with the tractography following white fibers and visualizing functional tracts. Cranial nerves tractography could allow predicting their displacement by skull base tumors that may help the surgeon to spare them along the surgery. Methods: Preoperative cerebral MRI was performed on patients who presented with skull base tumors. A 3 tesla MRI machine was used to acquire DTI sequence with specific parameters: 32 directions, slice thickness 2 mm, echo time 86 ms, repetition time 12000 ms, matrix 128x128, b-value 1000 s.mm-1. An anatomic sequence hyperT2 was overlaid as reference. Distortion was corrected by topup and eddy functions from FSL. Cranial nerves fibers were probabilistically tracked with Mrtrix3. Cranial nerves were selected according to their location around the tumor. The radiological expected position of the cranial nerve was compared to its operative real position.

Official Title
-----------------
Diffusion Tensor Imaging and Tractography for Cranial Nerves. Interest in Skull Base Surgery and Anatomy

Conditions
-----------------
Cranial Nerve Palsy

Intervention / Treatment
-----------------
* Procedure: preoperative cerebral MRI and operative findings


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients who present a skull base tumor that requires surgical removal Patients adult, informed and agreed Exclusion Criteria: Pregnant women Patients under 18 years old, unable to legally consent

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Skull base tumors<br>Patients who presented a skull base tumor that requires a surgical removal | Procedure: preoperative cerebral MRI and operative findings<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between the expected and the real position of the selected cranial nerve | Selection of one or multiples cranial nerves of interest due to their close relationship with the tumor. Comparison of its/their position on MRI and during surgery. | Date of preoperative MRI (<3 months before the surgery) | 
| Correlation between the expected and the real position of the selected cranial nerve | Selection of one or multiples cranial nerves of interest due to their close relationship with the tumor. Comparison of its/their position on MRI and during surgery. | at 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| postoperative cranial nerve palsy | comparison with preoperative status | at 3 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
RMI