Carotid and vertebral circulation: Clinical applications

Magnetic resonance angiography (MRA) is a broad term referring to a plethora of techniques, all of which can be used to directly image flow in arteries and veins in the extra- and intracranial circulation. These techniques include 2D and 3D time of flight (TOF), 2D and 3D phase contrast (PC), newer techniques such as 3D TOF with multiple overlapping thin slab acquisition (MOTSA), as well as contrast-enhanced MRA (CEMRA). Although intra- and extracranial MRA is a relatively young technique, many of the above-mentioned techniques are mature enough to be a staple part of routine, clinical MR protocols. Hence, their clinical applications, the technical background and the various pitfalls require familiarity from the neuroradiologists. This chapter summarizes the various established as well as emerging clinical uses of these techniques. Understanding the inherent complementary nature of many of the techniques is essential to maximize the diagnostic information for every individual patient. As the physics and the technical background of these techniques have been discussed elsewhere in this book, we stress on their clinical applications.