A 65 year old man with hypertension presents with lower abdominal pain and back pain. An expansive abdominal mass is palpated lateral and superior to the umbilicus. What is the single most discriminating investigation?

The key is E. Abdominal US. [Features like i) hypertension ii) abdominal pain iii) back pain iv)

expansile abdominal mass lateral and superior to the umbilicus are very much suggestive of abdominal

aortic aneurism. Single most discriminating investigation is abdominal ultrasound].