sinuses or cortical veins. It accounts for 10 to 15% of intracranial arteriovenous shunts. DAVF lacks a nidus. Signs and symptoms of DAVF are: headache, tinnitus, neurological deficits involving cranial nerves, and increased intracranial pressure. DAVF once ruptured, will produce intraparenchymal hemorrhage or SAH. Increase in number of vessels near dural venous sinuses as seen on CTA is suggestive of DVAF. 4DCT may increase the sensitivity of detecting DAVF. In MRI scans, susceptibility weighted imaging (SWI) and arterial spin labelling sequences (labelling protons in blood without the use of contrast media to determine blood flow) are useful in evaluating DAVF. The patterns of draining veins from the fistula determines the risk of DAVF rupture. Increased pressure within the dural venous sinuses causes backpressure into the cortical veins, thus making cortical veins more prone to rupture. The risk of hemorrhage is graded by Cognard and Borden grading systems. These grading systems are based upon the DSA. Cortical venous/cerebral venous sinus thrombosis Dural venous sinus thrombosis (DVST) and cortical venous thrombosis (CVT) commonly presents with headache, increased intracranial pressure, or seizures. DVST is more common than CVT. DVST are frequently caused by infections in the skull base, dehydration, thrombophilia, meningioma, and other dural tumours. On CT scans, brain parenchymal hemorrhage that does not confined to specific arterial territory along with hyperdense appearance on dural venous sinuses raises the suspicion of DVST. Further evaluation with CT venography, MR venography, and post gadolinium MRI provides accurate diagnosis of venous thrombosis and follow-up after treatment. These studies demonstrate thrombus as filling defect or lack of signal. Vasculitis/vasculopathy Those with vasculitis may be presented with headache, behavioural changes, neurological deficits, or intracranial bleeding. Sulcal SAH is the most common form of intracranial bleed caused by vasculitis. On CT scans, sulcal SAH is seen as hyperdensity within the cerebral sulcus, while on MRI, it is seen as hyperintensity on FLAIR sequence, and hypointensity on GRE/SWI sequence. DSA is important in making the diagnosis of vasculitis or vasculopathy. Mycotic aneurysm It is arterial outpouchings arise from distal cerebral arteries. These are pseudoaneurysm, caused by thrombus clogging the distal arteries, which results in inflammation and small tears at the site of occlusion. These inflammation and thrombis can caused by infective endocarditis, artificial heart valve or other heart problems. Similar to vasculitis, rupture of mycotic aneurysm also causes SAH in cerebral sulci, mostly located in the vertex. If mycotic aneurysm