Cardiac positron ER emission tomography (PET) for beginners

Cardiac positron emission tomography (PET) is finding increasing use as a measure of the effectiveness of antiatherosclerosis therapies. PET is a computer tomographic technique used to generate images of the three-dimensional distribution of a positron-emitting tracer The positron-emitting tracer N-13 ammonia can be used to generate images representing myocardial perfusion, and PET images recorded under conditions of acute stress with this tracer can be used to locale coronary artery stenosis. Three-dimensional myocardial perfusion data can be represented in a single image called a polar coordinate map and can, together with a tracer-kinetic model, be used to quantitate myocardial blood flow in real terms. Calculation of myocardial blood flow forms the basis of definition of a number of parameters for the measure of myocardial perfusion, including coronary flow reserve and coronary resistance. Three-dimensional myocardial perfusion data can also be used for semiquantitative image analysis.