Dr. Fishman is a Professor of Radiology and Oncology and the Director of Diagnostic Radiology and Body CT, Johns Hopkins Medical Institutions, Baltimore, MD.

In March of 2005, I served as moderator of the fourth in a series of Forums on the use of intravenous contrast in computed tomographic angiography (CTA) applications. Proceedings of each of the earlier Forums has been published as a special supplement to Applied Radiology , in print or online, or both.

CTA continues to evolve, especially as CT technology advances from 4- to 16- to 32- to 40- to 64-detector rows. At the same time, CTA is gaining wider acceptance with new and even more critical clinical applications. It is no longer performed at select academic healthcare institutions alone; rather, it is steadily becoming a mainstream application at many institutions.

The goals of this supplement, which is based on the March 2005 CTA Forum, are to:

• Describe the current state of the art of CTA;
• Explore how changes in CTtechnology influence the use of iodinated contrast media;
• Outline image acquisition and contrast administration protocols for a variety of CTA applications;
• Provide guidance to healthcare centers just beginning to do CTA; and
• Help experienced centers perform CTA more successfully.

Throughout the supplement, discussions on contrast administration focus on the selection of contrast agent; contrast volume, concentration, and rate of injection; the role of the saline chaser; the timing of contrast delivery relative to data acquisition; the role of image postprocessing; and the impact of contrast agents on image quality.

Another important focus is the role and advantages of isosmolar contrast medium, how to minimize or eliminate contrast-induced nephropathy, and the identification of high-risk patients and high-risk studies.

This supplement comprises an impressive array of review articles by a distinguished panel of experts. In addition to my own overview of 64-slice CT technology, Stanley Goldfarb, MD, from the University of Pennsylvania School of Medicine (Philadelphia, PA), pens an excellent review of contrast-induced nephropathy. Karen M. Horton, MD, from Johns Hopkins Medical Institutions (Baltimore, MD) addresses the controversies surrounding and appropriate role of whole-body CT screening. Geoffrey Rubin, MD, of Stanford University Medical Center (Palo Alto, CA), reviews the challenges and techniques for lower-extremity CTA. Julia R. Fielding, MD, of the University of North Carolina (Chapel Hill, NC), explores CTA of cystic renal masses. Finally, Ella Kazerooni, MD, of the University of Michigan Medical Center (Ann Arbor, MI), discusses present and future applications of cardiac CTA.

I would like to thank GE Healthcare for sponsoring the CTA Forum and for providing an educational grant in support of this publication, Anderson Publishing for producing this special supplement, and all of the Forum participants for preparing a comprehensive overview of the use of intravenous contrast in CTA.