Lisette van Dam

Chapter 7 114 We aimed to provide an overview of published literature and applied extensive literature searches to identify all relevant papers regarding the diagnostic performance of CT/CT venography and MRI for the diagnosis of CVT (search strategy detailed in Appendix 1 ). Papers were chosen if written in Dutch or English and evaluating the diagnostic accuracy of CT/CT venography and MRI in cerebral vein thrombosis. We only excluded case-reports and reviews. Notably, in previous publications various terminology has been used for CVT. In this review isolated thrombosis of the dural sinuses is referred to as cerebral sinus thrombosis and thrombosis of both dural sinus and cerebral veins as CVT. Computed tomography In the emergency setting, CT is often the imaging test of choice for patients presenting with acute focal neurological symptoms 5,10 , since it’s widely available, cost-effective and useful to rule out common neurological diagnoses. 14 CVT may present variable on CT ( Table 1 ). A direct sign of CVT on non-contrast CT (NCCT) is direct visualization of a thrombus which is predominantly caused by the protein factor of haemoglobin within red blood cells, often called the “dense clot sign” or “dense vessel sign” ( Figure 1A ). 15 After the administration of a contrast agent the thrombus can directly be visualized as a filling defect within a dural sinus also called “empty delta sign”, which is specific for thrombosis of the superior sagittal sinus. 2,9 On CT indirect signs of CVT are often seen and may occur in 60-80% of cases. 14 Common indirect signs on CT that are highly evocative of CVT are multiple bilateral lesions (e.g. bilateral parasagittal hemispheric lesions are suggestive of superior sagittal sinus thrombosis), bilateral thalamic edema (can be found in deep cerebral vein thrombosis) and temporo-occipital lesions (suggestive for transverse sinus thrombosis). 14,16,17 Cerebral hemorrhage is also a common finding in patients with CVT, present in approximately 40% of patients. 18 Juxtacortical hemorrhages, small hemorrhages with limited or no edema, localized at the junction between the superficial and deep venous drainage system, are seen in up to 12% of CVT patients and are very specific for CVT and almost exclusively occur in superior sagittal sinus thrombosis. 18 There are several studies that evaluated the diagnostic accuracy of direct and indirect signs on NCCT. These studies (with sample sizes ranging between 7 and 588 patients), which were all retrospective, mostly small and using different reference standards (CT venography, MRI, DSA and/or multiple imaging and