Attenuation measurements on non-contrast-enhanced CT brain: a re-visit of their role in the diagnosis of cerebral venous thrombosis.

Abstract

Purpose: To determine the diagnostic merit of using quantitative imaging parameters measured on non-contrast CT (NCCT) in the diagnosis of cerebral venous thrombosis (CVT).

Materials and methods: 43 patients with CVT and 30 age and sex-matched controls were enrolled in this retrospective study. Two blinded neuroradiologists independently assessed the NCCT scans for direct and indirect signs of CVT. Absolute attenuation values of thrombosed and non-thrombosed sinuses were measured and the ratio of sinus attenuation to patient's hematocrit (H/H ratio) was calculated for each case. The attenuation value of the internal carotid artery was also measured to calculate the veno-arterial (V/A) difference. Inter-reader agreement was evaluated and all measurements were compared between patient and control groups.

Results: The sensitivity and specificity of the dense sinus sign for diagnosis of CVT ranged from 72 to 79% and from 83 to 87% respectively. Sinus attenuation, H/H ratio and V/A difference were significantly higher in the CVT group than in the control group (P < 0.0001). An attenuation threshold value of > 55 HU yielded a sensitivity of 86% and a specificity of 90% and had the largest AUC of 0.89 (95%CI 0.795-0.951) among all stand-alone parameters, while the combination of an attenuation value greater than 55, or a V/A difference greater than 22, yielded the best diagnostic performance among all the parameters with sensitivity and specificity at values of 86% and a 100% respectively and an AUC of 0.93 (95%CI 0.846 to 0.977).

Conclusions: Overall, the analysis of quantitative parameters resulted in a notable upgrade in the accuracy of the diagnosis of CVT over visual inspection alone. Their high specificities make them reliable markers of CVT, yet their relatively lower sensitivities may indicate a need to perform further studies to safely eliminate the possibility of CVT in highly suspicious cases.

Trial registration number: FMASU R 10/2020/2021.