Cerebral sinovenous thrombosis. Neuroimaging diagnosis and clinical management

Abstract

Cerebral sinovenous thrombosis (CSVT) is an uncommon disorder that affects the dural venous sinus and cerebral vein. In our study, thirty- four patients were examined. Pre and/or post contrast-enhanced CT was done in 28 patients. MRI studies were done in 24 patients. 2-D TOF MR venography (MRV) and contrast-enhanced MRV (CEMRV) were done in 19 cases. Digital subtraction angiography (DSA) was done in 18 patients. Sixteen patients received systemic intravenous heparinization, and 12 received endovascular thrombolytic treatment with urokinase combined with anticoagulant therapy. Neuroimages of CSVT can be acquired by direct visualization of the thrombus within the dural sinus or by parenchymal changes secondary to venous occlusion. As there are some pitfalls to MRI in the diagnosis of CSVT, the combination of MRI and MRV is now the gold standard in the diagnosis of CSVT. Usually, accuracy can be improved by applying 2-D TOF MRV and CE MRV. Furthermore, the source image of MRV is critical in differentiating between normal sinus variations and diseased ones. DSA is the best tool for demonstrating dynamic intracranial circulation in CSVT and mostly is used for endovascular treatment. Systemic intravenous anticoagulant therapy with heparin is accepted as a first line treatment. Except for clinical manifestations after systemic heparinization, abnormal MR findings of parenchymal change can be used to determine when to initiate thrombolytic treatment. Endovascular therapy can be finished at the antegrade flow within the dural sinus and continuous anticoagulation is sufficient to facilitate clinical improvement. Clinical suspicion and excellent neuroimaging are crucial in making the diagnosis of CSVT. Proper management with anticoagulants and/or endovascular thrombolytic therapy is mandatory in preventing propagation of the thrombosis and improving the clinical outcome.

Figure 1

The intravascular thrombus (arrow) within the superior sagittal sinus is elucidated as hyperdensity on non-contrast CT (A), the triangular defect (empty delta sign) on contrast enhancing CT (B), heterogeneous hyperintensity on sagittal T1WI (C) and axial T2WI(D,E) MR images. The 2D TOF MRV shows absence of right transverse sinus with incomplete filling of right sinus confluence (F).

Figure 2

The 2D TOF (A) and contrast enhancing MR venography (B) show decreased caliber of left transverse sinus (arrow). The source images of CEMRV (C, D) detect filling defects from the thrombus within the sinus (arrow). The venous phase of the vertebral angiogram (E) shows the small caliber of the left transverse sinus. During intracranial venous thrombolytic treatment (F), the venous sinus is reopened with residual thrombus (white arrow). The tip of the micro-catheter is in position (black arrow).

Figure 3

The axial section T2WI (A) and post-Gd enhancing (B) MR images show stage III parenchymal change with hyperintensity surrounded with mild edema (arrow) and faint contrast enhancement (black arrow) over both posterior and parieto-occipital regions. The empty delta sign (arrow) within the right transverse sinus on contrast enhancing sagittal MRI is evident (C). Poor visualization of the superior sagittal and both transverse sinuses on 2D TOF MRV is noted (D). The PA (E) and lateral view (F) in the venous phase of the carotid angiogram show the absence of both transverse sinuses and a filling defect (black arrow) caused by an intraluminal thrombus.

Figure 4

The T1 weighted MR image (A) shows diffuse intraluminal thrombus within the superior sagittal sinus (arrow). During retrograde transvenous thrombolytic treatment, the micro-catheter (arrow) is demonstrated on lateral view (B) with the presence of filling defects caused by the thrombi (black arrow) within both transverse sinuses (C). The patient received subsequent heparinization for 4 days and was improved clinically. The follow-up PA (E) and lateral (F) view of the CEMRV at two weeks shows a more patent venous sinus when compared to the lateral view of MR venography done the next day of treatment (D).