Contrast-enhanced MR angiography of the craniocervical vessels: a review

Abstract

The use of MR angiography (MRA) with injection of contrast medium enables imaging of a large volume with a very short acquisition time, providing angiographic images similar to those obtained with catheter angiography. This makes possible investigation of patients in the acute phase of stroke, with examination of the entire length of the cervical arteries from the aortic arch to the circle of Willis. However, the parameters of the sequence must be carefully chosen to optimise image quality, with a compromise between spatial resolution, acquisition time and image contrast. An overview of the technical aspects is presented, including current developments. Different protocol strategies are discussed, including their advantages and limits. Finally, we review the preliminary results of contrast-enhanced MRA for assessment of atherosclerotic lesions of supra-aortic vessels.

Contrast-Enhanced Three-Dimensional Magnetic Resonance Angiography of Atherosclerotic Internal Carotid Stenosis as the Noninvasive Imaging Modality in Revascularization Decision Making

“…7 The introduction of high-perfor-mance gradients allowed rapid acquisition in an attempt to image the first passage of paramagnetic contrast media in the arteries. Promising results have been reported by several authors in evaluations of supraortic vessels, 8,9 especially in cases of carotid pathology also with medium-field MR equipment. 10,11 The role of preoperative, noninvasive examinations in surgical decision making is currently debated.…”

Revised and Updated Recommendations for the Establishment of Primary Stroke Centers

“…MRA and CTA are capable of detecting abnormalities that can be missed by routine carotid Doppler such as stenotic lesions of the origins of the great vessels, intracranial stenoses, aneurysms, vasculitis, and some dissections. [103][104][105] The detection of such lesions might alter patient management for acute care as well as secondary prevention. 18 The inclusion of MRA and/or CTA reflects current standard imaging techniques widely available in the United States and is supported by numerous studies as well as imaging guidelines.…”

Imaging of Ischemic Stroke

“…It relies on injection of a paramagnetic agent such as gadolinium to reduce the T1 relaxation time of tissue and to generate contrast between the intravascular lumen and surrounding tissues [43]. Unlike TOF-MRA, vascular contrast is therefore relatively independent of flow dynamics, and artifacts associated with saturation effects are substantially reduced.…”

“…Vessels from the aortic arch to the circle of Willis can be obtained in less than 1 minute. This sequence enables potential assessment of stenosis or vessel occlusion [43]. CE-MRA is also used to demonstrate luminal narrowing in acute dissection ( Figure 3) [44].…”