A dilated mastoid emissary vein as a potential cause of pulsatile tinnitus.

BACKGROUND

Pulsatile tinnitus (PT) is commonly attributed to vascular etiologies; however, up to half of cases remain idiopathic.

OBJECTIVES

To investigate the association between the mastoid emissary vein (MEV) and PT and to identify MEV-related factors contributing to PT.

MATERIALS AND

METHODS

This retrospective study included 119 adults (237 ears; PT, 46 ears; non-PT, 191 ears) who underwent temporal bone computed tomography between January 2019 and July 2025. MEV presence, dilation, and morphological features were analyzed.

RESULTS

MEV was identified in 73.9% of PT ears and 61.3% of non-PT ears, without a significant difference. However, dilated MEV was significantly more common in the PT group (56.5% vs. 29.3%, OR = 3.13, p < 0.001). Among 151 ears with MEV, PT ears showed a higher prevalence of dilation (76.5% vs. 47.9%, OR = 3.54, p = 0.003). Mean MEV orifice diameter was significantly larger in the PT group on both axial and coronal images. MEV presence was also associated with concomitant venous abnormalities (OR = 2.05, p = 0.035).

CONCLUSIONS AND SIGNIFICANCE: MEV dilation is strongly associated with PT and frequently accompanied by venous abnormalities. Careful radiologic evaluation of MEV may help identify potential vascular contributors in patients with idiopathic PT.