Preface

Over the past 15 years, there have been numerous significant advances in magnetic resonance angiography (MRA). Developments in software and hardware have created the ability to image in near real time and at high resolution. Theoretic improvement in signal to noise of 3T systems is being realized in imaging of small vessels in the head, neck, and abdomen. Combined with parallel imaging and multichannel coils, four dimensional imaging is not only possible, but also is becoming common practice for many clinical applications.

This issue is a combination of clinical MRA examples and fundamental physics concepts that form the basis of MRA methods. Most of the techniques are introduced in the first article and are reinforced throughout the issue to give the reader an appreciation of how they work.

Contrast-enhanced MRA suffered a setback with the recognition of intravenous gadolinium administration's association with nephrogenic systemic fibrosis (NSF). Closer analysis seems to indicate that not all gadolinium contrast agents convey the same risk of developing NSF. Patients who have an estimated glomerular filtration rate of less than 30 mL/min/1.73 m2 may be affected with NSF, which has no known treatment or cure.

Renewed interest in non–contrast-enhanced techniques has also increased as a result of NSF. Techniques used for cine cardiac imaging can also be applied to other parts of the body with success. While there have been improvements in time of flight and phase contrast imaging, newer techniques, such as steady state free precession, have made non–contrast MRA a valuable tool in the MRA armamentarium.

Authors of the articles in this issue are recognized leaders in the advancement of MRA throughout the body. We thank them for their insight into this exciting field. This issue is a snapshot in time of MRA applications, and we hope the reader gains an appreciation of current state of the art and future technological trends.