Multislice CT angiography versus MR angiography In the evaluation of Sub arachinoid hemorrhage

Abstract

Sub-arachinoid hemorrhage refers to a leakage of blood into the subarachnoid space which is a continuous space between the supratentorial and infratentorial compartments.SAH originates from a focal source can be more diffuse and spread throughout wider aspects of the subarachnoid space. (Kirkpatrick,2008) Non traumatic cases of SAH usually are caused by extravasation of blood from abnormal blood vessels onto the surface of the brain ,this is the result of aneurysmal rupture.There is evidence that aneurysms arising from the posterior circulation (i.e. intracranial vertebral arteries and basilar artery and its branches, including the posterior cerebral arteries) are at increased risk of rupture compared with aneurysms arising from the anterior circulation (i.e. from the internal carotid arteries or its branches, including the posterior communicating arteries) and that if they do rupture , the outcome is poorer .The detection of the subgroup of posterior circulation aneurysms is therefore particularly important. (Newton et al,2005) The distribution of subarachnoid blood may be a strong clue