Thrombosis of inferior sagittal sinus

Case Discussion:

This is an unusual case of thrombosis of the inferior sagittal sinus. 

Cerebral venous sinus thrombosis (CVST) is a rare and potentially fatal condition. Presentation is highly variable depending on the etiology. 

Most frequent locations are the superior sagittal sinus, transverse and sigmoid sinus, sinus cavernosus, and sinus rectus. Thrombosis of the inferior sagittal sinus is very rare.

The main MRI sign of cerebral venous thrombosis is the lack of expected signal flow void on standard spin-echo T1- and T2-weighted images. T2*-weighted imaging is able to demonstrate areas of hypointensity in thrombosed veins and sinuses.

• In acute venous thrombosis, loss of flow void on T1-weighted images occurs along with hypointensity on T2-weighted images, mimicking a normal flow void and making the determination of sinus occlusion difficult
• In the subacute phase, blood clot can result in loss of normal flow void on T1-weighted images and T1 hyperintensity, as is demonstrated in this case
• After 30 days the thrombus gradually becomes isointense on T1-weighted images.

MR imaging is more sensitive than CT in demonstrating the parenchymal lesions.

References

1. Rodallec MH, Krainik A, Feydy A et-al. Cerebral venous thrombosis and multidetector CT angiography: tips and tricks. Radiographics. 2006;26 Suppl 1 : S5-18.doi:10.1148/rg.26si065505 - Pubmed citation
2. Elsherbiny SM, Grünewald RA, Powell T. Isolated inferior sagittal sinus thrombosis: a case report. Neuroradiology. 1997;39 (6): 411-3. Neuroradiology (link) - Pubmed citation