Myocardial Perfusion Imaging
Nuclear medicine techniques for imaging blood flow in the heart muscle are a well -- established method for evaluating patients at risk for coronary artery disease. Generally, these techniques are utilized when patients have symptoms or other clinical findings (such as abnormalities on their EKG) in order to determine whether they require further evaluation with more invasive techniques or to assess the severity of the problem in a patient with known heart disease. Broadly, these imaging methods involve administration of a very small amount of a radioactive tracer intravenously and acquiring a three-dimensional image of the heart with a special type of camera. This procedure is typically performed twice, once while the patient is resting and once just following "stress." The "stress" portion of the exam involves administration of an intravenous medication that dilates the vessels of the heart OR exercising on a treadmill. There are two different nuclear imaging modalities that can provide the three-dimensional pictures of the heart. The choice of the imaging method depends on certain patient-related parameters and the type of clinical data that is being sought.
Single photon emission computed tomography (SPECT), also known as "gamma-imaging", can image the heart muscle using a specific class of radioactive agents and is the most widely utilized nuclear cardiac imaging technique, available at all 5 RAS facilities where nuclear medicine is performed (Downtown Sacramento, Roseville, Carmichael, Auburn, Folsom). One RAS facility also offers SPECT-CT, a modality that combines nuclear SPECT imaging with an x-ray-based technique to account for potential artifacts due to soft tissues overlying the heart, a technique that is useful in patients with a large body habitus.
Positron Emission Tomography (PET) is another nuclear diagnostic imaging tool that may be used to image myocardial blood flow and perfusion. This type of imaging instrument is typically combined with Computed Tomography (CT) called a PET/CT . As opposed to SPECT myocardial imaging, PET is not susceptible to artifacts created by soft tissues overlying the heart; therefore, like SPECT-CT, it is commonly employed in larger patients. PET may also be requested by a physician when additional information over that found on SPECT images is required. Cardiac PET imaging is routinely available at the RAS facility in Downtown Sacramento.
Myocardial Viability Imaging
A PET Viability Cardiac scan is useful for differentiating between heart muscle that is dead versus muscle that is alive but just not functioning normally. This type of exam uses the same type of PET instrument described above, but the radioactive tracer that is used is different than the one used to see blood perfusion in the heart muscle. PET viability imaging can help to determine whether procedures such as an angioplasty would be beneficial. Following an event such as a myocardial infarction, or heart attack, it is important to establish the extent of damage incurred to cardiac tissues. A PET Viability Cardiac scan allows a physician to assess which areas of the heart are not functioning properly and whether the tissue is still alive and can recover if blood supply is restored to that area.
PET Viability Cardiac scans are performed at three RAS PET and Nuclear Medicine Imaging centers, located in Downtown Sacramento, Carmichael, and Roseville.
For more information or to schedule an appointment, please call (916) 453-9999
