Prevalence of a High-intensity Signal of the Oculomotor Nerve on T2 MRI Sequence in Patients With Ophthalmoplegia

Study Overview
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Brief Summary
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Oculomotor nerve (third cranial nerve or III) palsy is a relatively frequent cause of consultation in ophthalmology. It may reveal a life-threatening pathology such as aneurysm rupture, pituitary apoplexy, and therefore need imaging in emergency. Apart from few extreme emergency situations, MRI of the oculomotor tract is the first-line examination required. In the usual clinical practice, the investigators noticed in several patients unusual areas of high-intensity signal within the oculomotor nerve on T2 sequence, observed in various locations along the nerve path (cavernous and/ or intra-orbital segment). This abnormal signal, at the best knowledge of the investigators, has never been reported in the literature and could confirm the nerve impairment. In patients with ophthalmoplegia involving probably the third cranial nerve, disclosing this new MRI sign could help (i) to confirm the involvement of the oculomotor nerve and eliminate differential diagnoses such as myasthenia (ii) to orientate the etiological diagnosis (inflammatory or ischemic origin). A T2 sequence focused on the III could thus be systematically included in the usual MRI protocol.

Official Title
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Prevalence of a High-intensity Signal of the Oculomotor Nerve on T2 MRI Sequence in Patients With Ophthalmoplegia

Conditions
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Ophthalmoplegia

Intervention / Treatment
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* Diagnostic Test: MRI T2 sequence of the oculomotor tract


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ophthalmoplegia whatever the clinical form (unilateral or not, isolated or not, sudden or progressive onset) Exclusion Criteria: Absolute contraindication to MRI or injection of contrast agents

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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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: MRI T2 sequence of the oculomotor tract|Patients with ophthalmoplegia will benefit from an MRI T2 sequence of the oculomotor tract (additional time of 4 minutes).|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| High-intensity signal of the oculomotor nerve on MRI T2 sequence (presence or absence, determined by a radiologist) | High-intensity signal within the oculomotor nerve on T2 sequence, observed in various locations along the nerve path (cavernous and/ or intra-orbital segment). High-intensity signal on T2 MRI sequence is defined as a signal area which is more intense than the contralateral nerve or more intense than the white matter signal. A double separate reading of the imaging will be carried out by an experienced radiologist and a junior radiologist on anonymized MRIs, with no access to clinical elements and interpretation of the other radiologist. In case of discrepancy between the radiologists, the final decision will be made by a third experienced radiologist under the same conditions (no access to clinical data, no access to the other evaluations). | Baseline |