Noninvasive Diagnostic Services
Coronary Computed Tomography Angiogram (CTA) and Coronary Artery Calcium Score (CAS)
At GW Hospital, physicians use CT, a highly advanced, non-invasive scanner that has the ability to help doctors identify heart disease in minutes by capturing thousands of detailed cross-sectional images of the patient’s beating heart. These scans provide physicians with three-dimensional views that can show narrowed areas in even the smallest blood vessels as well as help identify early disease in vessel walls that may not be narrowed.
Magnetic resonance imaging provides detailed images without any radiation or injection of dyes. Using a powerful magnetic field and radio signals, the MRI examines blood vessels and can give details about how the blood is flowing throughout the body. It also provides important information on the structure of the heart and the integrity of the heart muscle.
A type of ultrasound, an echocardiography (also known as an “echo” or echocardiogram), is a diagnostic tool that uses high-pitched sound waves to produce an image of the heart. The sound waves are sent through a transducer placed on the surface of the chest and reflect off certain areas of the heart. The reflected soundwaves are then converted into pictures. This test is used to check the heart's ability to effectively pump blood throughout the body and measure how much blood is actually pumped in each contraction. This test also is used to evaluate valve function, find evidence of heart failure and confirm that the heart is normal size. There are several types of echocardiograms:
- Transesophageal (TEE)
This is a specialized test where an echo probe is passed through the mouth, into the esophagus. This gives the physicians better views, because the transducer is closer to the heart and allows physicians to identify problems such as clots in the heart, valve infection and certain types of congenital heart problems. Local and intravenous anesthetics are used with TEE to minimize any discomfort to the back of the throat.
- Stress Echocardiogram Test
Patients either exercise on a treadmill or are given a drug called Dobutamine in order to stress the heart or mimic the effects of exercise. An echocardiogram is performed before and after the exercise or medication infusion in order to see if the patient has evidence of coronary artery disease (blockage of the blood vessels that supply the heart with its blood supply).
- Arterial Ultrasound
This looks at plaque build-up in the arteries in the neck that supply blood to the brain to give physicians information about risk of stroke and evidence for peripheral artery disease. This test can also be done on the blood vessels in the legs.
Nuclear heart scans provide images that can reveal the flow of blood throughout the heart muscle, show how effectively the heart pumps blood through the body and check for damaged heart muscle. During this test, a safe, radioactive material, called a tracer, is injected through a vein into the bloodstream that travels to the heart. The tracer releases energy, which special cameras outside of your body can detect. The cameras use the energy to create images of different areas of the heart at rest or during exercise.
The George Washington University Hospital offers single photon emission computed tomography (SPECT), positron emission tomography (PET) and multi-gated acquisition radionuclide angiography (MUGA). When used with stress testing, these tests can show problems with blood flow to the heart that can be detected only when the heart is working hard and beating fast. Damaged or scarred heart muscle tissue from a previous heart attack or other injury may also be visible. The test also can reveal how well the heart's left ventricle pumps blood to the body. Weak pumping ability may be the result of heart attack, heart failure or other cause.