Cardiac nuclear medicine studies provide pictures of the structure and function of the heart.
Nuclear cardiology uses a very small amount of a radioactive dye, or tracer, that is injected into your bloodstream. This tracer makes it possible to take detailed pictures of your heart and the surrounding blood vessels.
Nuclear cardiology tests are used for several purposes, such as finding out if you are at increased risk of a heart attack or whether you may need heart surgery.
The amount of radioactive tracer used is very small—much less than the radiation in an X-ray—so risks are minimal. Still, patients who have asthma, glaucoma, a heart rhythm disorder or who have had a recent heart attack may not be appropriate for nuclear cardiology.
Physicians use cardiac nuclear medicine studies to help diagnose cardiac disease.
The symptoms include:
- unexplained chest pain.
- chest pain brought on by exercise (called angina).
Cardiac nuclear medicine imaging is also performed:
- to visualize blood flow patterns to the heart walls, called a myocardial perfusion scan.
- to evaluate the presence and extent of suspected or known coronary artery disease.
- to determine the extent of injury to the heart following a heart attack, or myocardial infarction.
- to evaluate the results of bypass surgery or other revascularization procedures designed to restore blood supply to the heart.
- in conjunction with an electrocardiogram (ECG), to evaluate heart-wall movement and overall heart function with a technique called cardiac gating.
PREPARATION FOR THE TEST
-You may be asked to wear a gown during the exam or you may be allowed to wear your own clothing.
-You should also inform them if you have any allergies and about recent illnesses or other medical conditions.
-You should inform your physician if you have asthma or a chronic lung disease or have problems with your knees, hips or keeping your balance, which may limit your ability to perform the exercise needed for this procedure.
-You should not eat or drink anything after midnight on the day of your procedure, but you may continue taking medications with small amounts of water unless your physician says otherwise. If you take beta-blocker medication (Inderal, Atenolol, etc.) you should specifically ask your physician about temporary discontinuation.
-Women should always inform their physician or radiologist if there is any possibility that they are pregnant or if they are breastfeeding their baby
HOW THE TEST IS PERFORMED?
The most common type of nuclear cardiology test is a myocardial perfusion scan.
After the tracer is injected, you are asked to exercise on a treadmill for several minutes. If you are not able to exercise, you may receive a drug that makes your body respond as if it had been exercising.
A special camera is then used to take pictures of your heart. This camera will detect the tracer as it passes through your heart and the surrounding blood vessels.
If your heart is healthy, there will be little difference between images of your heart following exercise and when it is at rest. If there are blockages in your coronary arteries, these will show up clearly.
EXAMPLES OF POSSIBLE NUCLEAR STRESS TEST RESULTS IN A SIMPLE WAY
-If the scan is normal during both exercise and rest,then blood flow through the coronary arteries is most likely normal as well.No significant coronary artery blockage is suspected.
-If the scan is normal at rest but abnormal following exercise then the heart isnt receiving enough blood when its under stress.This may be due to blockage in one or multiple coronary arteries.
-If abnormal blood flow is detected both at rest and with stress,this suggests that part of the heart has suffered injury in the past.This is often the case following a heart attack.
PATIENTS NOT SUITABLE FOR NUCLEAR STRESS TEST-CONTRAINDICATIONS
- Acute myocardial infarction within 48 hours
-Uncontrolled cardiac arrhythmia, which may have significant hemodynamic responses (e.g. ventricular tachycardia)
-Severe symptomatic aortic stenosis, aortic dissection, pulmonary embolism, and pericarditis.
-Multivessel coronary artery diseases that have a high risk of producing an acute myocardial infarction.
CONCLUSION-
Depending on the results of your nuclear cardiac stress test and your physical and clinical condition, coronary angiography and perhaps coronary artery dilation (ANGIOPLASTY) may be performed.
Sometimes coronary artery bypass surgery(CABG) is considered.
In other situations, medical management seems more appropriate.
These alternatives should be discussed with your doctor when you
get the results of your nuclear cardiac stress test.
 |
| NUCLEAR IMAGE |
No comments:
Post a Comment