Dilated emissary veins in patients with pulsatile tinnitus: Culprit or bystander?

Emissary veins (EVs) are common incidental radiological findings, and enlarged EVs have been associated with the development of pulsatile tinnitus (PT). The purpose of this study is to further investigate the prevalence and characteristics of EVs in patients with and without PT.

We conducted a case-control study of consecutive patients with PT and age- and sex-matched controls who received imaging (primarily CTA, CTV, and MRI) between February 2018 and February 2022. Radiological evaluation was performed by two neuroradiologists and EVs measurements were performed at the point of maximal diameter. For statistical analyses, Mann-Whitney U test was used to compare vein diameters, and Fisher's exact test was used to compare vein frequencies.

Condylar and mastoid emissary veins of any diameter were less frequently observed in patients with PT than controls (66% vs. 78%; p < 0.01). The median diameter of mastoid emissary veins (MEVs) was significantly greater in the PT cohort (1 [IQR 1-2] mm vs. 1 [1-1] mm; p < 0.01) but there was no difference in median condylar emissary vein (CEV) diameter (3 [2-4] mm vs. 2 [2-3.5] mm; p = 0.64). Dilated CEVs (≥ 5 mm, 11% vs. 4%; p = 0.02) and MEVs (≥ 2 mm, 30% vs. 13%; p < 0.01) were more common in patients with PT. In both the PT and control cohorts, there was no significant difference in the prevalence of dilated EVs in patients with and without significant internal jugular stenosis (IJVS), transverse sinus stenosis (TSS). Additionally, there was no significant difference in the prevalence of dilated EVs in patients with and without idiopathic intracranial hypertension (IIH) in the PT cohort.

Dilated CEVs and MEVs were more common in patients with PT compared to controls, while the overall prevalence of CEVs/MEVs was lower in the control cohort.There was no association between the prevalence of dilated EVs and the presence of significant IJVS or TSS in patients with PT or controls.