Specific Imaging Findings

The thrombosed cortical vein may be hyperdense on non-contrast CT or T1 bright on MRI. The underlying cortex may be edematous and occasionally adjacent subarachnoid hemorrhage is seen. The thrombosed vein is best demonstrated on T2* gradient echo and susceptibility-weighted sequences as an area of signal void. On FLAIR, the thrombus may be hyperintense, as is the underlying swollen cortex. Once hemorrhage occurs, the clot is obviously dense on CT and its MRI signal features vary according to its age. Isolated subarachnoid hemorrhage without parenchymal clots is occasionally seen. A hemorrhage in a non-arterial distribution involving both gray and white matter in a younger patient should raise the suspicion of a thrombosed cortical vein with secondary hemorrhage.

Pertinent Clinical Information

Most patients are adults who present with nonspecific clinical symptoms leading to delays in the appropriate diagnosis. The most common symptom is headache accompanied by signs of increased intracranial pressure. Once an infarct and/or hemorrhage occur, seizures frequently follow. Other symptoms such as altered mental status and paresis may also be present. The main risk factors are hypercoagulable states, pregnancy and malignant tumors. Because of its association with pregnancy, oral contraceptives, and smoking, venous thrombosis is more common in females, particularly younger ones. In children, dehydration due to fever and diarrhea and/or vomiting is the most commonly implicated cause. Patients with the syndrome of intracranial hypotension are also at risk for cortical vein thrombosis.