Advances in biomedical technology are making organ transplantation safer and more effective. For some, it is even helping to avoid the need for transplantation altogether. Patients with severe CAD (coronary artery disease) may become candidates for heart transplant when prolonged nutrient and oxygen deprivation due to blocked arteries has killed portions of their heart muscle. But using PET (positron emission tomography) imaging to detect cardiac viability can offer these hearts a second chance.
When an area of the heart is starved of blood by a blocked artery, the heart muscle (or myocardium) in that area dies and forms scars. If enough of the heart muscle has been compromised in this way, the organ can no longer do its job of pumping blood through the body. Decreased blood flow doesn’t always kill heart muscle, however. It can also simply render portions of the heart muscle dormant. Often referred to as “hibernating myocardium,” such living muscle is under-active, but can be revived by procedures to restore blood flow (revascularization) such as coronary bypass or angioplasty and stenting.
PET and Cardiac Viability
Hibernating myocardium must be properly detected. Routine tests that measure the amount of blood flow (perfusion) to the heart, such as the thallium test can underestimate the amount of hibernating myocardium that is present. PET, with its ability to detect cell metabolism, can distinguish the faint activity of dormant heart muscle. For this purpose, PET is recognized as offering the highest accuracy level of any non-invasive cardiac test.
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