Magnetic resonance angiography: current status and future directions

Abstract

With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renewed interest in these methods. This article discusses the current state of both contrast-enhanced (CE) and NCE-MRA. New CE-MRA methods take advantage of dose reduction at 3.0 T, novel contrast agents, and parallel imaging methods. The risks of gadolinium-based contrast media, and the NCE-MRA methods of time-of-flight, steady-state free precession, and phase contrast are discussed.

Is Migraine Related to Medial Meningeal Artery and Spinous Foramen Caliber?

“…The reason why there is limited number of studies conducted with humans is because, until recently, invasive methods have been required to make these findings. However, non-invasive sectional imaging methods such as MRA and CTA have been improved, now making it possible to visualize the thin vessels such as the MMA in a sensitive manner [9,10]. More recently, many hypotheses have decreased the role of vasodilation.…”

“…With the improvement of technology, it has been possible to visualize extremely thin vessels by Magnetic Resonance Angiography (MRA) and Computed Tomographic Angiography (CTA), and to make reliable measurements [9][10][11]. Additionally, the spinous foramen, which is the site of the entry of the MMA into the cranium, can also be visualized with the CT angiography.…”

MRI Catheterization in Cardiopulmonary Disease

“…Delineation of abnormal anatomy under fl uoroscopic guidance requires iodinated contrast injections, particularly in children with complex corrected or noncorrected congenital heart disease, whereas MRI offers unrivalled anatomic imaging without the need for contrast agents. 31,32 In adults with congenital heart disease, MRI is the recommended technique for diagnosis and management. 33 Both physicians and patients are increasingly mindful of medical radiation.…”

Understanding and Augmenting Collateral Blood Flow During Ischemic Stroke

“…Magnetic resonance angiography (MRA) uses MR imaging approaches to map blood vessels in the brain (Hartung et al, 2011). While there are several MRA variants, time-of-flight (TOF) MRA and contrast-enhanced (CE) MRA are most frequently used to image cerebral blood flow in patients with cerebrovascular disease (Barlinn & Alexandrov, 2011).…”

“…Both techniques allow either 2-dimensional (2D) or 3-dimensional (3D) volume acquisition and are capable of detecting aneurysms, occlusions or stenosis in cerebral vasculature, with the major differences being the requirement for a bolus injection of a contrast medium (gadolinium) for CE-MRA. Additionally, TOF-MRA permits higher-resolution images while CE-MRA allows faster collection over a larger anatomical volume, and reduced artefacts due to blood flow and vascular pulsation (Barlinn & Alexandrov, 2011;Hartung et al, 2011). Notably, MRA does not use ionization radiation, does not require an invasive catheter, and the "low-dose" contrast agent used with CE-MRA is considered less toxic than contrast media associated with conventional angiography.…”