Pulsatile tinnitus, one more piece in the jigsaw
Reviewed by Hassan Mohammed

Pulsatile tinnitus (PT) is a common ENT symptom. It can generally be divided into venous and arterial. Arterial PT might be investigated with a CT scan while a venous one with an MRI or an MRV (MRI Venogram). Anecdotally, arachnoid granulations (AG) appear to be more common in patients with pulsatile tinnitus. The authors explore the possible correlation between AG and PT. They retrospectively investigated MRIs and MRVs that were performed to assess tinnitus. Children and those with arterial tinnitus were excluded. Authors also looked for MRI and MRV scans that were performed for other indications to assess the prevalence of AGs. There were 250 patients with PT and 401 with non-pulsatile tinnitus (NPT) over the study period; 26/250 (4.1%) of the patients with PT had AGs as compared to 1/401 (0.25%) of the patients with NPT. The difference in prevalence of AGs between the PT and NPT was statistically significant. Of the 77,607 patients who had an MRI for another indication, 230 patients (0.30%) were found to have AGs. Of these, 32 (13.9%) patients were found to have PT on chart review. On average, patients with PT were more likely to have higher BMI, less likely to be Caucasian, and more likely to be female. These differences were statistically significant. The AGs in PT patients were significantly more likely to be in the lateral sinuses (sigmoid, transverse) than in patients without PT. There were no statistically significant differences in the incidence of obstructive sleep apnoea. Although PT patients were more likely to have a diagnosis of idiopathic intracranial hypertension (IIH) (46.9% versus 17.7%, p = 0.0002) in their medical record, they did not demonstrate typical radiographic signs of IIH more frequently than non-PT patients. Authors concluded that the significance of the presence of AGs in patients with PT remains unclear. They also commented that the presence of AGs does not necessarily increase the likelihood of coexistent IIH. This study highlights that the aetiology of pulsatile tinnitus is sometimes difficult to identify. It would have been helpful if the authors correlated the side of the AGs with the side of the tinnitus. It would also have helped if they included their method of differentiating arterial from venous PT.

Dural Venous Sinus Arachnoid Granulations in Patients with Pulsatile Tinnitus.
Bauschard M, Reichl K, Socolovsky L, et al.
OTOL NEUROTOL
2022;43(7):e787-90.