The use of intravenous dipyridamole in thallium 201 myocardial perfusion imaging

Thallium 201 myocardial perfusion imaging is a standard method of evaluating regional myocardial blood flow. Myocardial perfusion is best evaluated at rest and during exercise, however, alternative methods have been sought to increase coronary blood flow in patients incapable of performing adequate exercise. A promising new method is the use of intravenous dipyridamole for pharmacologic stress imaging. It has distinct advantages over traditional treadmill exercise testing. The primary advantage of combining intravenous dipyridamole and thallium 201 is for testing patients in whom exercise is impractical or contraindicated. Examples include patients taking beta blockers and those who have had myocardial infarction or have severe peripheral vascular disease. To date, this agent has been available only to clinical investigators in approved protocols. With continued success, it should be approved for general use in the near future.