Evaluation of vascular variations at cerebellopontine angle by 3-dimensional T2-weighted magnetic resonance imaging in patients with tinnitus

Objective: Anatomical interactions of vascular and neural structures at cerebellopontine angle (CPA) are considered related to auditory-vestibular symptoms. Magnetic resonance imaging (MRI) has become the preferred method to visualize this complex anatomical region. This study aimed to assess the relation of vascular loops at CPA with clinical symptoms in patients with tinnitus using 3-dimensional (3D) T2-weighted (T2W) MRI. Materials and Methods: The study included 476 patients, grouped as those with and without tinnitus, undergoing MRI for various clinical auditory symptoms. MRI scans were assessed regarding the presence of vascular abnormalities at CPA. Results: For the patients with tinnitus on the left side, the frequencies of Type 1 vascular loop (at the CPA level) (p=0.001) and Type A vascular loop (contact with the vestibulocochlear and facial nerves) (p<0.001) vascular loops were significantly higher. For the patients with tinnitus on the right side, only the frequency of Type A vascular loop was significantly higher (p=0.005). For the patients with bilateral tinnitus, Type 2 vascular loop (proximal to the internal auditory canal [IAC]) on the right side (p=0.035) and Type A vascular loop on the left side (p<0.001) were significantly higher. Conclusion: This study is the largest scale study investigating the tinnitus etiology using 3D T2W MRI. The frequency of vascular loops at the CPA and IAC primarily depends on the diagnostic technique. Our results indicated that vascular causes could be shown more clearly with the use of high-resolution imaging methods. Accordingly, treatment options can be better determined by the clarification of etiology