Non-contrast MR Angiography Research Articles

Improvement of Myocardial Perfusion Reserve Early After Coronary Intervention: Assessment With Cardiac Magnetic Resonance Imaging. Al-Saadi N, Nagel E, Gross M, et al. J Am Coll Cardiol 2000;36:1557–64

Flow-independent relaxation-based non-contrast MR angiography techniques yield good signal-to-noise ratio and high blood-tissue contrast, complementing non-contrast flow-dependent and contrast-enhanced MR angiography techniques in the assessment of vascular disorders. However, these techniques often suffer from imaging artifacts at high magnetic field strengths or across large fields-of-view. Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) is a recently introduced flow-independent non-gated non-contrast three-dimensional MR angiography technique that has been developed to mitigate some of these issues. We present our initial experience with the clinical applications of REACT in imaging disorders of the central and peripheral vascular systems.

Two-dimensional thick-slice MR digital subtraction angiography for assessment of cerebrovascular occlusive diseases.

Although spatial resolution of current MR angiography is excellent, temporal resolution has remained unsatisfactory. We evaluated clinical applicability of 2D thick-slice, contrast-enhanced subtraction MR angiography (2D-MR digital subtraction angiography) with sub-second temporal resolution in cerebrovascular occlusive diseases. Twenty-five patients with cerebrovascular occlusive diseases (8 moyamoya diseases, 10 proximal internal carotid occlusions, and 2 sinus thromboses ) were studied with a 1.5-T MR unit. The MR digital subtraction angiography (MRDSA) was performed per 0.97 s continuously just after a bolus injection of 15 ml of gadolinium chelates up to 40 s in sagittal (covering hemisphere) or coronal planes. Subtraction images were generated at a workstation. We evaluated imaging quality and hemodynamic information of MRDSA in comparison with those of routine MR imaging, non-contrast MR angiography, and X-ray intra-arterial DSA. Major cerebral arteries, all of the venous sinuses, and most tributaries were clearly visualized with 2D MRDSA. Also, pure arterial phases were obtained in all cases. The MRDSA technique demonstrated prolonged circulation in sinus thromboses, distal patent lumen of proximal occlusion, and some collateral circulation. Such hemodynamic information was comparable to that of intra-arterial DSA. Two-dimensional thick-slice MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics equivalent to that of intra-arterial DSA and may play an important role for evaluation of cerebrovascular occlusive diseases.