Magnetic resonance perfusion imaging in ischemic heart disease

This review explores the present status of contrast media available for myo cardial perfusion studies, the magnetic resonance (MR) sequences adapted to multi-slice first-pass acquisitions, and the issue of myocardial perfusion quantification. To date, only low molecular weight paramagnetic gadolinium chelates have been used in clinical protocols for myocardial perfusion. Wi th the availability of fast MR acquisition techniques to follow the first-p ass distribution of the contrast agent in the myocardium, the bolus trackin g technique represents the more widely used protocol in MR perfusion studie s. On T1-weighted imaging, the ischemic zone appears with a delayed and low er signal enhancement compared with normally perfused myocardium. Visual an alysis of the image series can be greatly improved by image post-processing to obtain relative myocardial perfusion maps. With an intravascular tracer , myocardial kinetics are in theory easier to analyze in terms of perfusion . In experimental studies, different intravascular or blood pool BIR contra st agents have been tested to measure quantitative perfusion parameters. If a simple now-limited kinetic model is developed with MR contrast agents, o ne important clinical application will be the evaluation of the functional consequence of coronary stenoses, ie, noninvasive evaluation of the coronar y reserve. (C) 1999 Wiley-Liss, Inc.