Yes, angiography is used to determine the blood flow to a specific area of the body, and MRI
angiography is a newer and increasingly popular approach to angiography. The second part of your question is less straight forward, however, as it is impossible to say if any kind of radiographic imaging is likely to localize your problem. There are many things that can cause you to lose feeling in your foot, and many of them would not necessarily be visible on any kind of imaging. For that reason, the full history and physical examination which your doctor
will perform will generally provide the framework of the other studies that might be needed.
If your doctor feels that you need an MRI angiography (also called an MRA), it could be because he or she is concerned that there is something compromising the blood flow to your foot, and an MRA may prove effective at providing the information that is needed to diagnose or treat the condition. Please speak to your doctor about the possible causes of the loss of feeling in your foot and what can be done about it, and be sure to mention any other medical conditions or symptoms that you may have.