Heart disease is our leading killer. Cardiac imaging and vascular imaging are critical in foreseeing an event before it happens. Our expert team supports one of the highest-volume centers in the country.
The Cardiac Imaging Division of RASF is staffed with dedicated fellowship-trained cardiac imagers with extensive expertise in advanced applications of Cardiac CT, Cardiac MRI and Nuclear Cardiology. The cardiac imaging section has pioneered the clinical implementation of non-invasive imaging for assessment of chest pain in the emergency department in the mid to late 90s with Nuclear myocardial perfusion imaging (MPI) and since 2008 with Coronary CTA.
We have one of the first and busiest dedicated Coronary CTA programs in the country covering five Hospitals and several Imaging Centers. Coronary CTA cases include patients presenting with acute chest pain from the Emergency Department; outpatients presenting with stable angina and/or non-diagnostic stress test and a strong prevention program using Calcium score among other indications. Cardiac MRI is performed mainly at Baptist Cardiac and Vascular Institute, and also at South Miami Hospital. Cases include viability assessment, non-ischemic cardiomyopathy, vasodilator mediated stress perfusion, cardiac masses, pericardial disease, congenital heart disease, valvular disease and shunt assessment.
Nuclear Cardiology cases include ischemia detection, viability assessment and ejection fraction calculations. In the past, patients would need to stay in the emergency room for up to 36 hours or be admitted to the hospital. By using coronary CTA, one of several tools used to evaluate chest pain, doctors are able to determine the diagnosis within less than 12 hours from arrival. The use of Coronary CTA has been proven to be cheaper, faster and safe in the assessment of low to intermediate risk patients presenting to the ED with chest pain, negative cardiac enzymes and non-diagnostic ECG.
Cardiac computed tomography is a painless test that uses a CT scanner to take clear, detailed pictures of the heart. This common test is used to look for problems in the heart.
During a cardiac CT scan, an x-ray machine will move around your body in a circle. The machine will take a picture of each part of your heart. A computer will put the pictures together to make a three-dimensional (3D) picture of the whole heart.
For CT angiography procedures, an iodine-based dye (contrast dye) is injected into one of your veins during the scan. The contrast dye travels through your blood vessels, which helps highlight them on the x-ray pictures.
Because an x-ray machine is used, cardiac CT involves radiation. Although the amount of radiation used is considered small, it's similar to the amount of radiation you're naturally exposed to over a period of one to three years. New cardiac CT methods are available that reduce the amount of radiation used for this test.
Overview
Different types of CT scans may be used for different purposes. For example, multidetector computed tomography (MDCT) is a fast type of CT scanner. Because the heart is in motion, a fast scanner is able to produce higher quality pictures of the heart. MDCT also may be used to detect calcium in the coronary arteries.
Researchers continue to study new and better ways to use cardiac CT. Physicians at Radiology Associates of South Florida are in the forefront of research in Cardiac Imaging.
Magnetic resonance imaging (MRI) is a safe, noninvasive test that creates detailed pictures of your organs and tissues. "Noninvasive" means that no surgery is done and no instruments are inserted into your body.
MRI uses radio waves, magnets, and a computer to create pictures of your organs and tissues. Unlike computed tomography scans (also called CT scans) and standard x rays, MRI doesn't use ionizing radiation.
Cardiac MRI creates pictures of your heart as it's beating, producing both still and moving pictures of your heart and major blood vessels. Doctors use cardiac MRI to get pictures of the beating heart and to look at its structure, function, myocardial perfusion and viability. These pictures can help them decide how to treat people who have heart problems.
Cardiac MRI is a common test. It's used to diagnose and evaluate a number of diseases and conditions, including:
Cardiac MRI can help explain results from other tests, such as echocardiograms and nuclear scans. Sometimes, cardiac MRI is used to avoid the need for invasive procedures or tests that use radiation (such as x rays) or dyes containing iodine (these dyes may be harmful to people who have kidney problems).
Often during cardiac MRI, a contrast agent is injected into a vein to highlight portions of the heart or blood vessels. This contrast agent often is used for people who are allergic to the dyes used in CT scanning.
People who have severe kidney or liver problems may not be able to have the contrast agent. As a result, they may have an MRI that doesn't use the substance (a non-contrast MRI).
Nuclear cardiology studies use noninvasive techniques to assess myocardial blood flow, evaluate the pumping function of the heart as well as visualize the size and location of a heart attack. Among the techniques of nuclear cardiology, myocardial perfusion imaging is the most widely used.
Myocardial perfusion images are combined with exercise to assess the blood flow to the heart muscle. Exercise can be in the form of walking on the treadmill or riding a stationary bicycle. A "chemical" stress test using the drug dipyridamole, adenosine or dobutamine can be performed in patients who are not able to exercise maximally, providing similar information about the heart's blood flow.
A small amount of an imaging agent - thallium or sestamibi (Cardiolite) or tetrofosmin (Myoview), is injected into the blood stream during rest and during exercise or chemical stress. A scanning device (gamma camera) is used to measure the uptake by the heart of the imaging material during exercise or chemical stress and at rest. If there is significant blockage of a coronary artery, the heart muscle may not get enough of a blood supply in the setting of exercise or during chemical stress. This decrease in blood flow will be detected by the images.
Myocardial perfusion studies can thus identify areas of the heart muscle that have an inadequate blood supply as well as the areas of heart muscle that are scarred from a heart attack. In addition to the localization of the coronary artery with atherosclerosis, myocardial perfusion studies quantify the extent of the heart muscle with a limited blood flow and can also provide information about the pumping function of the heart. Thus, it is superior to routine exercise stress testing and provides the necessary information to help identify which patients are at an increased risk for a heart attack and may be candidates for invasive procedures such as coronary angiography, angioplasty and heart surgery.
Evaluation of Cardiac Function with Radionuclide Ventriculography—Radionuclide ventriculography is a noninvasive study, which provides information about the pumping function of the heart. In patients with coronary artery disease, and in those who have had a heart attack, the assessment of the pumping function of the heart (also known as the ejection fraction) is essential in the prediction of both long term and short-term survival. A small dose of an imaging agent is injected into the blood stream and pictures of the four chambers of the heart are taken using a special camera (gamma camera). These techniques can also provide information about the function of the valves of the heart, the integrity of all the cardiac chambers and can be used to monitor the effect of different drugs on the heart muscle (in patients with cancer who are treated with chemotherapy). The evaluation of cardiac function with radionuclide ventriculography is accurate and noninvasive and continues to play a critical role in predicting outcomes in patients with heart disease.
Assessment of Myocardial Injury, Infarction and Infection—The basic cellular component of the heart muscle may be irreversibly affected in the setting of a limited blood supply and or inflammation. Nuclear cardiology techniques can be used to determine which areas of the heart muscle have been damaged by infection or by a heart attack. These techniques can also be used to monitor the status of the heart muscle in the patient after cardiac transplantation.
