Contrast-enhanced MRA of intracranial vessels.

Despite the possibility of performing high quality and diagnostically useful examination of the intracranial vasculature using time-of-fight (TOF) and phase contrast (PC) MR angiography, there are still some intrinsic technical problems that limit the application of these techniques. Many of these problems, particulary those related to flow effects, can be avoided by the use of a suitable contrast agent. To avoid the problem of super-imposition of veins, ultrafast gradient echo MRA techniques with very short TR and TE have been developed. Although the precise sequence parameters vary between different manufacturers, they are similar. The choice between a time resolved or high spatial resolution CE-MRA technique is dependent upon the precise clinical application. The most common applications include the study of cerebral aneurysms, arterio-venous malformations, dural arterio-venous fistulas and venous diseases.