Background: Unenhanced computed tomography (CT) is a frequently used imaging method in patients who are evaluated in the emergency department with suspected cerebral vein thrombosis (CVT). Objectives: The aim of this study was to investigate the usefulness of the Hounsfield unit (HU) value determined by CT and its ratio to the patient's hematocrit (Htc) value in the diagnosis of cerebral vein thrombosis. Methods: This retrospective study evaluated 41 patients with acute cerebral venous sinus thrombosis and 41 age- and sex-matched control participants. Two experienced observers independently evaluated the CT scan and measured the attenuation of the dural sinuses. Results: There was no significant difference in age, gender, hemoglobin, and Htc values between the two groups. The mean HU value was 75 +/- 7 HU in the CVT group and 52 +/- 6 HU in the control group (p < 0.001). The mean HU/Htc ratio was 1.9 +/- 0.3 in the CVT group and 1.3 +/- 0.1 in the control group (p < 0.001). The optimal threshold value for HU was determined as 66, and sensitivity at this value was 93 %, and specificity was 98 %. The optimal threshold value for HU/Htc was determined as 1.64, and the sensitivity at this value was 90% and the specificity was 100 %. Conclusion: Hyperattenuation in the dural sinuses and the HU/Htc ratio in unenhanced brain CT scans have high diagnostic value in detecting CVT. (C) 2021 Elsevier Inc. All rights reserved.