Cardiac MRI for assessment of myocardial perfusion: current status and future perspectives.

Cardiac magnetic resonance imaging (MRI) has recently been applied successfully to the assessment of myocardial perfusion. Cardiac MRI offers potential advantages over radioisotopic techniques because it provides superior spatial resolution, does not use ionizing radiation, and has no imaging orientation constraints. Current MRI perfusion approaches measure the alteration of regional myocardial magnetic properties after the intravenous injection of contrast agents. Several studies have validated the ability of perfusion MRI to detect the presence of significant coronary artery stenoses by detecting decreased signal intensity upslope or reduced maximal enhancement in the ischemic territories. Perfusion MRI has also been shown to assess accurately the extent of injury after a myocardial infarction and the presence of myocardial viability. With the introduction of newer contrast media, technologic improvements on MRI hardware and software, and the enhancement of quantitative analysis, MRI is likely to become a clinical tool for assessment of myocardial perfusion imaging in the near future.