that exerts mass effecct on adjacent brain. Follow up CT scan is recommended. Those with extension of bleed into the ventricular system, expansion of bleeding, or increasing cerebral oedema on CT scan gives poorer prognosis. CT angiography (CTA) of brain can be performed to investigate the source of bleeding. An image during the delayed phase of the CTA may be taken to look for pooling of contrast that signifies active bleeding (known as "Spot sign"). Presence of "Spot sign" signifies poor clinical outcome for the subject. Cerebral amyloid angiopathy Cerebral amyloid angiopathy (CAA) is the deposition of Amyloid beta peptide protein within the brain. Accumulation of such peptide proteins within the walls of the arteries can cause weakening of the walls and causes microhemorrhages, SAH within the cerebral sulci or large cerebral intraparenchymal bleed. SAH in CAA can be differentiated from vasculitis by its presentations. SAH in CAA usually occurs in those who age more than 60 years, temporary motor and sensory deficits, and intracranial bleed in white matter adjacent to cerebral cortex. Basal ganglia, posterior fossa, and brainstem are spared. Boston criteria is used to determine the likelihood of a cerebral hemorrhage due to CAA. Definitive diagnosis of CAA is by performing brain biopsy CT scan may show hyperdense intra-axial hemorrhage in the subcortical region. Diffuse white matter hypodensities in both cerebral hemispheres may represents microangiopathic changes. On MRI these lesions will be presented as blooming artifact on gradient echo and susceptibility weighted imaging. Hemorrhagic conversion of ischemic infarction 43% of those with infarcted brain tissue will develop hemorrhagic conversion. Risk of hemorrhagic is further increased with recanalisation of veins or arteries. Several types of hemorrhages can occur such as petechial hemorrhages around the infarcted margin (HI1), confluent petechial hemorrhages within the infarcted tissue (HI2), hematoma occupying less than 30% of the infarcted tissue (PH1), hematoma involving greater than 30% of infarcted tissue with small mass effect (PH2), and hematoma involving greater than 30% of the infarcted tissue with significant mass effect. However, only PH2 is clinically significant. Those who has infarction should be monitored frequently with CT brains to access hemorrhagic conversions or worsening vasogenic oedema that may require neurosurgical decompression. Dual energy CT scan maybe useful to differentiate the high densities caused by reperfusion hemorrhage (bleeding after endovascular stroke treatment) and high density due to iodinated contrast administered during cerebral angiography. Cerebral aneurysm Besides from head injury,