Could duplex ultrasound replace arteriography in screening for mesenteric ischemia?

No: The problem with any ultrasound is that it has to penetrate a number of layers before reaching its target. In the abdomen, it has to penetrate the skin, fat (some have more than others), muscle, & some organs. Also, seeing active blood flow requires a clear picture not hindered by other overlying or nearby blood vessels. Therefore, the abdomen is not ideal. Angiography gives a direct, clear view.

Doppler: Is screening tool for mesenteric ischemia. If abnormal cta should then evaluate the vessels to determine treatment options.

No screening: There is nothing called screening for mesenteric stenosis. If you have no symptoms then you no need to screen for occlusion. If you have chronic symptoms then duplex ultrasound is a good starting test but has a lot of limitations. In cases of acute ischemia then ct scan is best to start with.