<prompt> A 40 years old female is came in the depament by describing 1 have worst headache of my life. The investigation of choice for this patientFour vessels carotid angiographyComputed tomography CTMRINo scan is required  <response>: Answer- B. Computed tomography CTIt is a case of acute subarachnoid hemorrhage.The explosive onset of severe, excruciating headache is a common feature of subarachnoid haemonhage SAH.Diagnosis of Subarachnoid hemorrhageThe hallmark of aneurysmal rupture is blood in the cerebrospinalfluid.More than 95 cases have enough blood to be visualized on a high quality non contract CT scan obtained within 72h.MRI can also be used to diagnose subarachnoid hemorrhage but CT is more sensitive than MRI for acute blood 