Quantitative non-contrast measurements improve diagnosing dural venous sinus thrombosis

The only direct sign of sinus thrombosis on non-contrast computerized tomography (NCCT) is the hyperdense sign. The purpose of our study was to assess quantitative parameters for diagnosis of superficial venous sinus thrombosis and to compare these quantitative criteria with the current standard of qualitative evaluation. This retrospective case-control study included 18 patients with acute superficial sinus thrombosis and 18 matched controls. Three blinded readers independently evaluated the NCCT for the presence of hyperdense sign using axial slices only followed by axial slices with multiplanar reformats. Absolute attenuation values and ratios were calculated for thrombosed and non-thrombosed sinuses: Ratio_{target sinus/lowest attenuation sinus}, Ratio_{target sinus/basilar artery}, Ratio_{target sinus/internal carotid artery}, Ratio_{target sinus/temporal lobe}, and Ratio_{target sinus/frontal lobe}. There was a significant difference in absolute attenuation values and ratios between thrombosed and non-thrombosed sinuses, with the absolute attenuation and the Ratio_{target sinus/lowest attenuation sinus} being the most differentiating. The mean attenuation for thrombosed sinuses was 69 Hounsfield units (HU) (95 % CI 65-72 HU) vs. 52 HU (95 % CI 51-54) for non-thrombosed, P < 0.0001. The mean Ratio_{target/lowest attenuation} was 1.5 (95 % CI 1.4-1.6) for thrombosed sinuses vs. 1.1 (95 % CI 1.0-1.1) for non-thrombosed, P < 0.0001. Optimal thresholds of 62 HU and 1.3 yielded sensitivities of 81 and 84 %, respectively. Hyperdense sign had a sensitivity of 63 % on axial images and 67 % with the addition of multiplanar reformats. Density measurements result in substantial improvement over visual inspection in the diagnosis of superficial venous sinus thrombosis on NCCT. (orig.)