mrcem2-2198

A 65-year-old woman is brought in by ambulance to the resuscitation area of your Emergency Department. She developed sudden onset chest pain and then collapsed while exercising at home. On examination, she is pale and sweaty, and you can palpate a pulsatile mass in her abdomen. You suspect that she has a ruptured abdominal aortic aneurysm (AAA).
What is the most suitable initial imaging technique for evaluating this patient?