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CARDIAC SPECT IMAGING WITH |
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Nuclear cardiology SPECT scanning identifies groups of patients with more than a 20-fold increased risk of subsequent cardiac events. How Cardiac Imaging with SPECT Is Done The heart of the new nuclear cardiology laboratory is a system that combines technetium-99 sestamibi with a high-performance multi-head gamma camera, enabling the team to assess, virtually simultaneously, cardiac function and regional cardiac blood flow. For the test, very small doses of radioactive tracer are injected into the patient's arm vein. The gamma camera can detect the tracer as it passes through the heart chambers, during the blood pool phase, after it has been delivered through the coronary arteries to the cardiac muscle. A dramatic picture - in vivid color - of the heart at work (or at rest) appears on the computer screen linked to the gamma camera. Computerized analyses of regional heart function and blood flow are clearly displayed as color-coded maps. Continuous movies of the heart in motion reflect the accurate statistical average of hundreds of heart beats, pictures that reveal which areas of heart muscle and coronary arteries are healthy and which are damaged or at risk. If a patient is unable to exercise, cardiac stress is induced with medications. The system also provides rapid analysis of heart pump function by analyzing the blood tracer activity in the pools of blood within the heart chambers and by quantifying the percentage of blood pumped from them. Top row: Patient studies with stress. Bottom row: Patient studies at rest. (a) filtered back projection reconstruction of static Tl-201 (no attenuation correction), (b) reconstruction of summed (5 minute) teboroxime data, (c) Estimates of kinetic wash-in parameters. (d) Estimates of wash-out parameters. |
