Intracranial vascular lesions: optimization and clinical evaluation of three-dimensional time-of-flight MR angiography.

Abstract

The clinical value of three-dimensional time-of-flight magnetic resonance (MR) angiography was prospectively evaluated in 26 patients with congenital intracranial vascular lesions; 12 had arteriovenous malformations (AVMs), and 14 had venous angiomas. In the initial phase of the study the entire region of interest was imaged with one large acquisition volume (60-120-mm-thick slab). Later, the angiograms were obtained with adjacent but slightly overlapping, 30-mm-thick slabs, which clearly improved vascular detail. Gadolinium enhancement slightly improved depiction of veins but not of arteries. MR angiograms were compared with available conventional angiograms and MR studies. The topography of the AVM nidus was equally well appreciated on the MR as on the conventional angiograms. However, in six of 12 patients the hyperdynamic afferent arteries were incompletely shown on MR angiograms because of incomplete rephrasing. In three patients, venous drainage was also incompletely visualized. Compared with conventional MR studies, MR angiography offered the same detection rate but better anatomic insight. Thirteen of the 14 venous angiomas were also identified on MR angiograms. Detailed imaging, however, necessitated gadolinium enhancement and thin-slab acquisition.

Critical Neck Position as an Independent Risk Factor for Posterior Circulation Stroke

“…Measurements were taken with the neck in four different positions and with all grades of compression at the proximal and distal vertebral arteries and basilar artery levels. The accuracy of 20 phasecontrast [37][38][39] and 20 TOF sequences reliably correlated with conventional angiography [28,[40][41][42].…”

Magnetic resonance angiography. Cerebrovascular applications.

“…6 ' 18 If this 3D MRA is combined with intravenous gadolinium, the difficulty with spin saturation (and intravascular signal loss) in the draining veins and distal nidus vessels is further reduced. 6 Regardless of the technique MRA cannot provide the physiologic information that can be derived from traditional catheter angiography such as the arteriovenous circulation time and arterial stump pressures. Edelman et al 23 -24 showed that it was possible to obtain some functional information with respect to identifying feeding vessels through the use of appropriately positioned saturation pulses.…”

Simple Assessment of Cerebral Hemodynamics Using Single-Slab 3D Time-of-Flight MR Angiography in Patients with Cervical Internal Carotid Artery Steno-Occlusive Diseases: Comparison with Quantitative Perfusion Single-Photon Emission CT

“…20,21 These spins are gradually saturated during movement within the slab. This saturation effect causes signal intensity loss in the peripheral arteries.…”