Is an open mra and mrv good enough to diagnose any abnormalities with the blood vessels even without contrast?

It depends : Vascular surgery is based upon a physical examination and is confirmed by these type of imaging studies. If you are looking for issues of flow contrast is helpful. If you are looking for issues of structure, e.g. Av malformations that may be useful without contrast although in the end you will want flow information in order to establish a treatment plan.

For the most part: Both mr angiography (mra) and mr venography (mrv) of the head are usually performed without contrast dye using a special technique that can "see" flowing blood without IV contrast. Open mri? Depends on the machine. Some newer MRI scanners have larger openings without being "open, " and these strike better balance between patient comfort and image quality. May still miss small vascular lesions.