The relationship between tinnitus and vascular anomalies on temporal bone CT scan: a retrospective case control study

Tinnitus is a common symptom in which etiology is unclear in a group of patients. Some of anatomic or vascular variations diagnosed on temporal bone computed tomography (CT) has been known to cause tinnitus particulary pulsatile form. Therefore significance of these anatomic variations has not been validated in patients with nonpulsatile tinnitus. The aim of this study is to ascertain several anatomic variations previously attributed to pulsatile tinnitus in nonpulsatile tinnitus patients. And secondly to assess the relationship between the amount of sigmoid sinus bulging and mastoid emissary vein (MEV), enlargement of those was not evaluated before in tinnitus patients.

Retrospectively, temporal bone CT scans of 70 patients with an existing complaint of tinnitus with unexplained etiology were enrolled. As a control group, 70 patients were selected from paranasal sinus CT scans without any otological or clinical findings.

The type of tinnitus was subjective and nonpulsatile in the overall group. The diameters of enlarged MEV on the left side were significantly higher in the tinnitus group. Carotid canal dehiscence and high riding jugular bulb were significantly higher in the tinnitus patients. Petrous bone pneumatization was significantly lower in the tinnitus patients than in the control group.

In patients who complained of subjective nonpulsatile tinnitus with unknown etiology, some temporal bone vascular variations, including high riding jugular bulb, dehiscent carotid canal, left-sided MEV enlargement, and petrous bone pneumatization, seemed to have an association with tinnitus. Further studies comparing all these entities between pulsatile and nonpulsatile groups and healthy controls should be undertaken.