The significance of vascular loops in the internal auditory meatus: a true incidental imaging finding?

PURPOSE: To determine the clinical significance of vascular loops (VL) in the internal auditory meatus (IAM) and cerebellopontine angle (CPA).

METHODS

We carried out a retrospective case series in a tertiary referral centre. Out of 6978 patients undergoing magnetic resonance imaging (MRI) of the IAM for unilateral cochleovestibular symptoms we identified the ones with VLs and reviewed their medical notes. We performed a statistical correlation between the laterality of the VL in the IAM/ CPA as graded according to the Chavda classification (type 1 in the CPA, type 2 extending in the IAM, type 3 extending to the distal IAM end), the laterality of symptoms and the patient's age.

RESULTS

A total of 77 VL were identified in 64 patients (0.9%); 39 patients had the VL on the same side of the main symptom, while 25 patients had the VL on the contralateral side. There were 37 Type 1 loops, 29 Type 2 loops and 11 Type 3 loops. The comparison between the grading of the VL and the laterality of symptoms did not reach the level of significance (p = 0.321). There was also no association between the presence of the loop and the patients' age (p = 0.5). All patients were reassured and discharged without any representation in three years follow-up.

CONCLUSIONS

We did not identify any significant correlation between the laterality of VLs and the laterality of symptoms, irrespective of the grading of the loop or the patients' age. Such VLs should be considered an incidental rather than causal findings.