Sinus Thrombosis with SAB
Patient presents for scheduled MRI with symptoms of headaches and with known arachnoid cyst in the posterior fossa. FLAIR sequence has revealed unexpected finding of Subarachnoidal Hemorrhage (SAB) in sulci adjacent to falx cerebri (arrowheads). Location of the SAB was not 'typical' for aneurysm and there was no history of trauma. The same FLAIR sequence has shown Venous Sinus Thrombosis in the left transverse and sigmoid sinus. Diagnosis was confirmed with CT Venous Angiography. Teaching point here is that 'strange' hemorrhage or atypical infarction should alert radiologist for possible source of the problem in the cerebral venous system. In this case SAB was most likely caused by ruptured cortical vein due to congestion of blood. We saw no sign of cortical vein thrombosis. It remains to be seen if the known arachnoid cyst in this case is predisposing factor or not related to venous thrombosis.
Some other cases of Sinus Thrombosis: here and here.