A 50-year-old man presents with thunderclap headache to the ED. Initial noncontrast CT head within 1 hour of onset is negative. He remains neurologically intact. Next best step to assess for SAH if suspicion remains high?ADischarge; negative CT rules out SAH at any timeBCT angiography or lumbar puncture to evaluate furtherCEmpiric migraine therapy onlyDMRI brain without contrast onlyEStart anticoagulation for suspected venous thrombosisCheck my answer