====== Cerebellopontine angle arachnoid cyst diagnosis ======

===== Magnetic resonance imaging =====

MRI (magnetic resonance imaging) scan techniques have led to [[cerebellopontine angle arachnoid cyst]]s being more frequently diagnosed and with a higher degree of certainty. The need for further understanding of their [[natural history]] as well as for the development of a management rationale has been highlighted with this increased rate of [[diagnosis]].

{{::cerebellopontine_angle_arachnoid_cyst_mri.jpg?300|}}

In the series of Alaani et al., these lesions have a characteristic location in the posterior-inferior aspect of the CPA below the [[facial nerve]] and [[vestibulocochlear nerve]]s. These cysts did not show a change in size on repeated MRI scans and the patient's symptoms did not progress over the period of follow up
((Alaani A, Hogg R, Siddiq MA, Chavda SV, Irving RM. Cerebellopontine angle
arachnoid cysts in adult patients: what is the appropriate management? J Laryngol
Otol. 2005 May;119(5):337-41. PubMed PMID: 15949094.
)).
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Both [[vestibulocochlear nerve]]s (VIII) with normal and symmetrical caliber and morphology are identified, with no evidence of areas of focal thickening that suggest the existence of intra or extracanalicular [[vestibular schwannoma]]. The round image up to 21mm in the right [[cerebellopontine angle]] follows the [[fluid]] [[signal]] in all the sequences and displaces the origin of the 
the [[facial nerve]]s (VII), and the [[vestibulocochlear nerve]]s (VIII), anteriorly.
Findings are suggestive of a right [[cerebellopontine angle arachnoid cyst]].

{{::cerebellopontine_angle_arachnoid_cyst_cases_from_the_general_university_hospital_of_alicante.jpg?200|}}