Many stress tests being done today have two parts, the stress test and the pictures of your heart. The investigators are comparing a newer technique to obtain the pictures (PET imaging) to the standard method (SPECT imaging). However, it is not known if the new test is better than the old test. It is important to have a standard to compare these tests to, and that is why people who will be getting a cardiac catheterization are being asked to participate. The information about your arteries from the cardiac catheterization will be used to judge which stress test is better. The investigators hypothesize that the newer method (PET imaging) will be more accurate than the old method (SPECT) in detecting heart disease.