Petro-trigeminal Line and Petrous Apex Cephaloceles

cephaloceles are rare lesions of the petrous apex, inconsistently listed as meningoceles or arachnoid cysts. They're consistent with a herniation posterolateral of the Meckel cavum within the petrous apex. These lesions may be the cause of a symptomatology varied, or be discovered by chance in subjects who have not been asymptomatic. Currently, there is no evidence in the literature a simple, fast and reproducible radiological marker that allows for the diagnosis of cephaloceles of the petrous apex, in particular the small ones. The purpose of this study is to validate a radiological benchmark simple and reproducible, the trigeminal petrol line, in order to improve the diagnosis of petrous apex cephaloceles

Inclusion criteria:Major subjects (≥18 years old)patients who underwent an MRI with high resolution 3D T2 sequence between 01/01/2003 and 09/31/2020:200 patients consulting for ENT pathology such as vertigo9 patients presenting the radiological criteria in MRI of a cephalocele of the petrous apex according to the current data of the literature on a T2 3D HR sequence- Subject who has not expressed his opposition, after being informed, to the reuse of his data for the purposes of this research.Exclusion criteria:Subject who expressed their opposition to participating in the studyKinetic ArtifactsSubject under guardianship or curatorshipSubject under safeguard of justice