13th June 2023

A 45-year-old woman with no past medical history presents to A&E with a sudden onset of a severe occipital headache

A 45-year-old woman with no past medical history presents to A&E with a sudden onset of a severe occipital headache with pain radiating down to her neck. There is no history of preceding trauma. Her initial non-contrast CT brain is normal, and she goes on to have a lumbar puncture which is positive for xanthochromia.

Which of the following options is the correct next investigation?