What are the disadvantages of TOF MRA?
The sequence is limited for assessment of vessels that have a tortuous course, such as the splenic artery, and is also limited for assessment of vessels that do not run perpendicular to the plane of section. It is not as good for assessing veins, because blood flow in veins is slower. Furthermore, it does not distinguish high-grade stenosis from moderate-grade stenosis as well as contrast-enhanced MRA.