<prompt> A patient presents to the emergency department of AIIMS with the most severe headache of his life. What should be done next?Contrast enhanced computed tomography CTNoncontrast CTMagnetic resonance imaging MRILumbar puncture LP  <response>: ANS. B Investigation of choice in subarachnoid hemorrhage SAH: Noncontrast CT Investigation of choice in aneurysm: DSA Investigation which can diagnose ischemia in brain earliest: MRI diffusion weighted imaging, within 3-30 minutes First imaging investigation to be done in a patient with suspected stroke: Noncontrast CT. 