Abstract
Background: Tinnitus, sensory neural hearing loss (SNHL), and vertigo are common audio-vestibular symptoms. Many diseases are associated with these symptoms; however, the exact cause is not always identified. Some studies show that the etiology could be related to the presence of a vascular loop in contact with the 8th cranial nerve. Three-dimensional (3D) constructive interference in steady state (CISS) is a fully refocused gradient-echo magnetic resonance imaging (MRI) sequence that has high sensitivity in evaluation of the cranial nerves. This high sensitivity is a result of its inherent ability to accentuate the T2 values between cerebrospinal fluid (CSF) and adjacent anatomical or pathological structures. We aimed to evaluate the association of audio-vestibular symptoms with the presence of vascular loops and vascular contact in cerebellopontine angle (CPA) and the internal auditory canal (IAC) using 3Tesla MRI. The study included 98 patients (196 ears); 51 females and 47 males with audio-vestibular dysfunction symptoms in isolation or combined; 40 patients with tinnitus, 50 with sensory neural hearing loss, and 32 with vertigo. The healthy control group with no symptoms in either ear,n= 60 (120 ears): 32 females and 28 males. The non-symptomatic ears in the patients were added to the healthy control group. All MRI examinations were performed by using a 3 T (Magnetom Verio 3 T; Siemens Medical Solutions, Erlangen, Germany).
Results: No statistically significant association was detected between the presence of different grades of vascular loop or types of vascular contact and any of the studied audio-vestibular symptoms.
Conclusion: No possible role of the presence of vascular loop/contact was identified in causing tinnitus, deafness, or vertigo as evaluated by 3D-CISS sequence. Therefore, presence of vascular loops in contact with the 8th cranial nerve is not certainly considered pathological but possibly to be a normal anatomical coincidental finding.