Dynamic 3-D contrast-enhanced angiography of cerebral tumours and vascular malformations

We describe the applicability and clinical use of dynamic 3-D contrast-enhanced MR subtraction angiography performed at 3 T with parallel imaging and intelligent k-space readout for imaging both treated and untreated cerebral arteriovenous malformations (AVMs), AV fistulae (AVFs) and brain tumours. An in-plane submillimetre spatial resolution with temporal resolution of one image per 1.3 s was obtained. The spatial resolution was comparable to that of other MRA techniques (i.e. TOF or PC MRA) while the scanning time was markedly reduced and the evaluation of both the arterial and venous vessels was possible with the same imaging sequence. Additional clinical information could be obtained for a variety of CNS disorders. Concerning AVMs, dynamic contrast-enhanced 3-D MRA helped to identify the arterial feeders, the shunting volume, and the location and size of the nidus. However, we found that the most important clinical application was the assessment of shunt occlusion following treatment (i.e. radiosurgery, surgery, or embolization) by determining the absence or presence of early venous filling following injection of contrast agent. Moreover, our MRA technique helped to noninvasively diagnose and classify arteriovenous dural shunts with regard to shunting volume, arterial feeders, and, most importantly, venous drainage pattern. For preoperative imaging of meningeomas, displacement of normal arteries, depiction of tumour feeders and anatomy of the venous system including the tributaries to the large sinuses, their patency, the location of bridging veins, and the extent of tumour vascularization could be assessed. Our findings indicate that dynamic 3-D MRA can help to reduce the scanning time by eliminating additional TOF or PC MRA sequences. With the same imaging sequence, both arterial and venous information can be obtained in a short period of time. In addition, haemodynamic information can be obtained, which may be of importance for a variety of clinical questions. The number of invasive examinations can be reduced during follow-up after treatment of AVF or AVM, and the need to treat dural AV shunts can be assessed noninvasively. In the preoperative investigation of meningeomas, all pertinent information (degree of vascularization, tumour feeders, displacement of arteries, and assessment of large veins) is obtained using a single sequence. We conclude that this MRA sequence may be an alternative to current MRA approaches and will prove an important adjunct for the diagnosis of a variety of neurovascular disorders.