Factors Affecting Attenuation of Dural Sinuses on Noncontrasted Computed Tomography Scan

Noncontrasted computed tomography (NCCT) is used as the initial neuroimaging test of choice for patients who present with new-onset neurological symptoms. An apparently hyperattenuated venous sinus may lead to the suspicion of cerebral venous sinus thrombosis (CVST). Improved understanding of all factors that can affect attenuation of dural sinuses can guide triage of patients to or from further investigations of suspected CVST. The purpose of this retrospective study was to assess the effect of different factors including hematocrit (HCT), hemoglobin (Hb), age, BUN/Cr ratio (blood urea nitrogen-to-creatinine ratio), and gender on the attenuation of dural sinuses on brain NCCT.

A total of 1293 patients with neurological symptoms who presented to the emergency department were included in this study. For each patient, clinical assessment, laboratory investigations, and brain NCCT were reviewed. For each brain NCCT, the average attenuation of superior sagittal sinus and both right and left sigmoid sinuses was measured.

Positive significant correlations were found between average attenuation of dural sinuses on one hand and each of age, Hb, and HCT on the other hand. No significant correlation was found between average attenuation and BUN/Cr ratio. Gender discrepancy was also significant as higher attenuation was found in men.

Age, gender, and Hb levels are the main factors that should be taken into account upon the assessment of dural sinuses on brain NCCT. The highest normal attenuation is predicted in an elderly polycythemic man and the lowest is predicted in a young anemic woman.