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Stroke and Transient Ischemic Attacks of the Brain and Eye
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Postcontrast CT in a patient with cerebral venous sinus thrombosis may show the “empty delta” sign, which is characterized by enhancement of the wall, but not the center of the posterior part of the sagittal sinus, when imaged cross-sectionally in the axial CT plane (Figures 12.27 and 12.28).
Neurology cases
Published in Lt Col Edward Sellon, David C Howlett, Nick Taylor, Radiology for Medical Finals, 2017
Arrow A points to the anterior portion of the superior sagittal sinus. It is filled with contrast as expected on this CT venogram and appears normal. Arrow B points to the posterior portion of the superior sagittal sinus. There is no contrast filling the sinus (the ‘empty delta sign’) because it is obstructed by thrombus. The diagnosis is, therefore, venous sinus thrombosis: this appears as low density material within the sinus. A thin layer of contrast can be seen to outline the low density, dark, thrombus.Venous sinus thrombosis is a poorly understood condition associated with risk factors including the oral contraceptive pill, pregnancy, prothrombotic states, and malignancy. The presentation often is nonspecific.Sinus thrombosis may lead to venous hypertension, cerebral oedema, and venous infarction.
Test Paper 7
Published in Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike, Get Through, 2017
Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike
The classic finding on unenhanced CT is a hyperattenuating thrombus in the occluded sinus (delta sign). However, this is seen in only 25% cases. Increased attenuation in the venous sinuses may also be seen in patients with dehydration, an elevated haematocrit level, or a subjacent subarachnoid or subdural haemorrhage. On contrast-enhanced CT/MRI, the empty delta sign is seen, a central intraluminal filling defect that represents a thrombus surrounded by contrast-enhanced dural collateral venous channels and cavernous spaces within the dural envelope. Unenhanced MRI is more sensitive for the detection of venous thrombi than is unenhanced CT. The absence of a flow void and the presence of altered signal in the sinus is a primary finding. Slow or turbulent flow also may cause a signal intensity alteration in the sinus.
A sickle cell disease patient with dural venous sinus thrombosis: a case report and literature review
Published in Hemoglobin, 2019
Michael K. Wang, Ravi Shergill, Matthew Jefkins, Jason Cheung
Diagnosis of DVST relies heavily on imaging to identify the presence of a thrombus in the dural venous sinuses. Non-contrast CT scans demonstrate abnormalities in only 30.0% of cases, and hence, are often initially missed. Hyperdensity in the posterior aspect of the superior sagittal sinus (‘dense triangle sign’) and ischemic lesions crossing arterial boundaries are common findings indicative of DVST on plain CT [30]. On contrast-enhanced CT, thrombus in the superior sagittal sinus is often visualized as a central hypointesity surrounded by contrast enhancement with a triangular shape (‘empty-delta sign’). Thrombi may appear isodense in the subacute or chronic setting, and in such cases CT venography is often helpful. If available, magnetic resonance imaging (MRI) combined with venography (MRV) is preferred as it is more sensitive than CT. Ischemic events occurring in the direct vicinity of the venous duct are particularly often better appreciated on MRI compared to CT. More invasive methods of diagnosis, such as cerebral angiography and direct cerebral venography, are rarely used [31].