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MUGA

September 23, 2011 in Health Library, Medical Tests

A multi-gated acquisition scan (also called equilibrium radionuclide angiogram or blood pool scan) is a noninvasive diagnostic test used to evaluate the pumping function of the ventricles (lower chambers of the heart). During the test, a small amount of radioactive tracer is injected into a vein. A special camera, called a gamma camera, detects the radiation released by the tracer to produce computer-generated movie images of the beating heart. The MUGA scan is a highly accurate test used to determine the heart’s pumping function.

How should I prepare for the test?

  • There is no special preparation required for this test; there are no medication or food restrictions.
  • Wear comfortable clothes that can be easily removed, as you may be asked to wear a hospital gown during the test.

What happens during the test?

  • A technician will attach electrodes (small, round adhesive patches) to the skin of your chest. Men may have their chest hair shaved to allow a better connection. The electrodes are attached to an electrocardiograph monitor (EKG) that charts your heart’s electrical activity during the test.
  • An intravenous (IV) line will be inserted into a vein in your arm.
  • The technician will ask you to lie on the exam table under the gamma camera. A nuclear imaging technician will draw a small amount of blood, combine it with a radioactive tracer, and inject the mixture into your IV. The radioactive tracer tags your red blood cells, so they can be detected by the camera. The tracer stays in your bloodstream for several hours and does not enter your tissue cells.
  • The camera above the table is focused on the heart and analyzes the amount of radio-labeled red blood cells pumped from the heart with each heartbeat. Several images can be taken to look at you different walls of the heart.
  • This test calculates your ejection fraction, a measurement of how well your heart pumps with each beat. A normal ejection fraction ranges from 50-70 percent. An ejection fraction of 65 percent, for example, means that 65 percent of the total amount of blood in the left ventricle is pumped out with each heartbeat. The ejection fraction may be lower when the heart muscle has become damaged due to a heart attack, heart muscle disease (cardiomyopathy), or other causes.

Are there any side effects from the injections during the test?

Because the injected medications contain only a minimal amount of the carrier drug, there are no significant side effects. The radioactive tracer used during the MUGA scan is a diagnostic dose of radiation that is similar to the dose you would receive during a CT scan.

How long will the test take?

The MUGA scan takes about one to two hours to perform.

What happens after the test?

You can resume your normal activities right after the test.

How will I get my test results?

After the cardiologist reviews your test, the results will go into your electronic medical record. Your referring physician will have access to the results and will contact you to discuss them.

 

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SILENT ISCHEMIA

September 7, 2011 in Conditions, Health Library

Ischemia is a condition where the flow of oxygen-rich blood to a part of the body is restricted. Cardiac ischemia refers to lack of blood flow and oxygen to the heart muscle.

Cardiac ischemia happens when an artery becomes narrowed or blocked for a short time, preventing oxygen-rich blood from reaching the heart. If ischemia is severe or lasts too long, it can cause a heart attack (myocardial infarction) and can lead to heart tissue death. In most cases, a temporary blood shortage to the heart causes the pain of angina pectoris. But in other cases, there is no pain. These cases are called silent ischemia.

Silent ischemia may also disturb the heart’s rhythm. Abnormal rhythms such as ventricular tachycardia or ventricular fibrillation can interfere with the heart’s pumping ability and can cause fainting or even sudden cardiac death.

How common is silent ischemia, and who is at risk?

The American Heart Association estimates that 3 to 4 million Americans have episodes of silent ischemia. People who have had previous heart attacks or those who have diabetes are especially at risk for developing silent ischemia. Heart muscle disease (cardiomyopathy) caused by silent ischemia is among the more common causes of heart failure in the United States.

Major risk factors include

  • Previous heart attacks.
  • Coronary artery disease
  • Diabetes
  • High blood pressure (hypertension)
  • Coronary artery anomalies
  • Smoking.
  • Obesity.
  • Cardiomyopathy.
  • Alcohol and drug abuse.

What are the symptoms of silent ischemia?

Silent ischemia has no symptoms. But researchers have found that if you have episodes of noticeable chest pain, you may also have episodes of silent ischemia.

How is silent ischemia diagnosed?

The following tests can be used to diagnose silent ischemia:

  • An exercise stress test can show blood flow through your coronary arteries in response to exercise, usually walking on a treadmill.
  • Holter monitoring records your heart rate and rhythm over a 24-hour period (or longer). You wear a recording device (the Holter monitor), which is connected to disks on your chest. Doctors can then look at the printout of the recording to find out if you have had episodes of silent ischemia while you were wearing the Holter monitor.

How is ischemia treated?

Treatment for ischemia is similar to that for any form of cardiovascular disease and usually begins with the following lifestyle changes:

  • If you smoke, quit.
  • Control high blood pressure, cholesterol, and diabetes.
  • Limit how much alcohol you drink.
  • Adopt healthy eating habits.
  • Start an exercise program that has been approved by your doctor.

Medicines and Surgery

The goals of treatment include improving blood flow to your heart and reducing your heart’s need for oxygen. Your doctor may give you aspirin, blood-thinning medicines (called anticoagulants), or other blood-thinning agents to prevent blood clots from forming. Oxygen may be given to increase the oxygen content of the blood still flowing through your heart. Painkillers may be used for pain.

Some patients take medicines that slow their heart rate, open and relax their blood vessels, and otherwise reduce the burden on the heart. Most patients respond well to these medicines. Those who do not respond well may need a percutaneous coronary intervention (PCI) such as balloon angioplasty, angioplasty, coronary artery bypass surgery, or a similar procedure.

 

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NUCLEAR EXAMS

September 1, 2011 in Homepage, Medical Tests, Uncategorized

Nuclear Medicine uses a small amount of radioactive materials to diagnose and treat a variety of diseases. Differing from x-ray, which demonstrates anatomy or structure, Nuclear Medicine provides information on how parts of the body function. The radioactive material is administered by IV injection, inhalation and/or by mouth. The radioactive material is attracted to specific organs, bones or tissues in the body. Special cameras are used to detect the location of the radioactive material.
Nuclear Medicine is safe and painless. Reactions to the radioactive material are rare. However, prior to the administration of any radioactive material, it is important to know and tell your physician and the Nuclear Medicine Technologist if you are pregnant or nursing. Special precautions or a delay in performing your procedure may be necessary. The most common procedures are described below.

Heart Perfusion Scan with Stress Test

Why This Procedure is Done: Heart perfusion scan is performed to evaluate narrowing (atherosclerosis) of the coronary arteries, which supply blood to the heart muscle.
Preparation: No caffeine for 24 hours prior to the exam. The meal prior to your exam should be low fat, and you should have nothing by mouth 4-6 hours before the exam. Continuation of medication is determined by your physician.
How the Procedure is Performed: A small needle will be placed into a vein in your arm or hand. A radioactive agent will be dispensed through the needle. The radioactivity circulates approximately 45 minutes. After this waiting period, there will be a 16 minute scan to look at the blood flow to the heart muscle. During the scan you will lie on your back with both arms resting above your head. After the first set of images you will have a stress test.
There are two ways to do the stress test: exercise on a treadmill, or you will be given medication to mimic exercise. Your physician will determine which type of stress test you will have. Whichever type of stress test you have, a second injection of radioactivity will be given. You will return to the Nuclear Medicine area for a second set of images, similar to the first. The rest and exercise images are compared to determine sufficient blood supply to the heart during exercise. A decrease in blood supply can be the source of chest pain and narrowing of the coronary artery, which could be a source of future heart attack.


How Long the Procedure Takes: Please allow approximately 3 hours for your appointment.

Hepatobiliary With or Without Ejection Fraction

 

Why This Procedure is Done: This procedure is done to evaluate the function of the liver, biliary tree, gallbladder, and bile ducts for possible obstruction. It may also be used to evaluate contraction of the gallbladder, which if abnormal may justify surgical removal
Preparation: Nothing by mouth 4-6 hours before the exam. No Dilaudid for 18-24 hours before the exam. No other narcotics for a minimum of 8 hours before the exam.
How the Procedure is Performed: A Hepatobiliary scan uses radioactivity to obtain images of the liver, biliary tree and gallbladder. The radioactivity is administered through a needle in a vein in your arm. There are no side effects to the injection. Images are taken for one hour. You will lie on your back. There are small breaks if you need to move during the scan. After the hour if any ejection fraction is requested, we ask you to drink a serving of Ensure Plus and return in 60 minutes for an additional image. This allows us to determine how well your gallbladder contracts.
How Long the Procedure Takes: Please allow approximately 60-120 minutes for your appointment.

 

Bone Scan – Whole Body or Three Phase

Why This Procedure is Done: This procedure is done to obtain functional images of your bone and joint structure. It is generally performed to evaluate skeletal pain, possible tumor or bone infections.
Preparation: There is no preparation for this procedure.
How the Procedure is Performed: A radioactive injection is given into a vein, which circulates for two to three hours. There are no side effects to the injection. After this waiting period, images can then be obtained of a specific area or from head to toe. At your physician’s request, we may also review blood flow to a specific area such as the feet or hands. This review will occur by taking images during the injection.


How Long the Procedure Takes: Please allow approximately 30-90 minutes for your appointment.

 

Thyroid Uptake and Scan

Why This Procedure is Done: This procedure images the structure and measures the function of your thyroid gland. The images will determine if the thyroid is homogeneous or if it has nodules within the gland. The function or uptake portion of the procedure will determine if your thyroid is overactive (hyperthyroid), normal (euthyroide) or underactive (hypothyroid). It is a two day test.
Preparation: You should not have x-ray procedures with IV contrast 6-8 weeks prior to this exam. Routinely you will be asked to discontinue your thyroid medication. The time varies with the type of medication. Your appointment will be scheduled accordingly. The first day you will be asked to swallow a capsule with radioactive iodine. This begins the function part of the test. You will be asked to return the following day for completion of the function portion and imaging.
How the Procedure is Performed: We will use a special machine to determine function or see how much of the radioactive iodine has been absorbed by your thyroid gland. The second part of this test is a thyroid scan. For this, an injection is given into a vein of a different radioactive isotope. This is allowed to circulate for about 15 minutes before images are obtained. Four images are obtained to determine size and homogeneity (all areas functioning equally). The images are coordinated with the uptake information to assist the Radiologist in providing a diagnosis.


How Long the Procedure Takes: Please allow approximately 20-30 minutes for day one of your appointment and 30-60 minutes for day two of your appointment.

 

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STRESS TEST (Exercise Electrocardiogram)

August 7, 2011 in Health Library, Homepage, Medical Tests

The exercise Stress Test — also called a stress test, exercise electrocardiogram, treadmill test, graded exercise test, or stress ECG — is a test used to provide information about how the heart responds to exertion. It usually involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty, while your electrocardiogram, heart rate, and blood pressure are monitored.

 


Category: Cardiovascular system.
Subcategory: Graphic recording.
Material studied: Graphic recording of electrical activity generated by the heart during exercise.
Estimated cost of test: $200.00.
Patient time for test: 45-60 minutes.
Reliability of test results: Good. Other tests, studies and clinical observations are necessary to establish a precise diagnosis.
Available as home self-test? No.

BEFORE THE TEST

Purpose of test:

  • Helps diagnose cause of chest pain.
  • Determines functional capacity of the heart after surgery or myocardial infarction*.
  • Screens for heart disease (particularly in men over age 35) when no symptoms are present.
  • Helps set limitations for an exercise program.
  • Identifies cause of abnormal heart rhythms that develop during physical exercise.
  • Evaluates effectiveness of heart medications.Where is test performed?
  • Commercial laboratory, hospital, doctor’s office, outpatient or free standing surgical facility.Who performs test?
  • Lab technician, nurse, doctor.Risks and precautions:
  • This test places considerable stress on your heart. It may be a hazardous test if you have a heart aneurysm*, uncontrolled disturbances in your heartbeat, inflammation of the sac surrounding your heart, inflammation of the heart muscle, severe anemia*, uncontrolled hypertension*, unstable angina* or congestive heart failure*. Stop the test immediately if you experience any chest pain, extreme fatigue or other complications.
  • A doctor is available in the testing area at all times.Patient preparation:
  • Activity–Do not smoke for 3 hours before the test.
  • Diet–Do not eat any foods or drink any beverage that contain caffeine or alcohol for 3 hours before the test.
  • Medicines–Inform the person performing the test if you have recently taken any medications listed under Taking these drugs may affect test results. You may be asked not to take this medication before the test.
  • Disrobing–Remove all clothing. Put on surgical gown.

    THE TEST

    Sensory factors:

  • Feeling–Some degree of apprehension or fear is normal and should be expected. Discomfort disappears when the test is finished. Test will cause you to feel fatigued, slightly breathless and sweaty. You may stop the test if you feel extreme fatigue or chest pain.
  • Other senses (touch, smell, hearing, taste, sight)–Not affected.Equipment used:
  • Blood-pressure equipment.
  • Shaver.
  • Alcohol solution.
  • Cotton swabs.
  • Chest electrodes.
  • Electrode paste.
  • EKG machine, with monitor.
  • Lead wires.
  • Treadmill or stationary bike.
  • Adhesive tape or rubber belt.Description of test:
  • You or a close relative will be required to sign a consent form after the procedure has been explained to you.
  • A doctor and emergency equipment are in the testing area at all times during the stress test.
  • Several areas on your chest and possibly your back are cleaned and shaved to prepare the skin for the electrodes. The electrode sites may itch slightly, but you won’t feel any current from the electrodes.
  • Your blood pressure and heart rate are checked periodically throughout the test.
  • Monitor is started.
  • Readings are taken while you are in a resting condition. The pattern of the heartbeat segments recorded is compareä to normal heartbeat patterns.
  • An electrogram (EKG) and blood pressure readings are taken while you walk on a treadmill or pedal a stationary bicycle.
  • Treadmill starts at a slow speed with a flat incline. You walk on it, balancing on a support in front of you. Don’t bear your weight on the support.
  • Speed and slope are increased until your heart reaches a predetermined target rate.
  • Exercise stops. EKG continues to monitor you for 10 to 15 minutes.
  • Electrodes are removed.

    AFTER THE TEST

    Immediate post-test care:

  • You are helped to a chair, where your heart rate and blood pressure are monitored for 10 to 15 minutes.Activity after test:
  • Sites where chest electrodes were attached are cleaned.
  • Resume taking any medications that were withheld before the test.
  • Wait at least 1 hour before you shower. Use warm water when showering because hot water may cause you to feel dizzy or faint.
  • Resume normal diet.Time before test results available:
  • Time before results are reported to the doctor or patient varies from a few minutes to a few days.

    TEST RESULTS

    Test values:

  • Test results are determined by study of EKG tracings following monitored, controlled exercise.Normal values:
  • No unexpected changes on EKG tracings.What ABNORMAL may indicate:
  • Multivessel coronary-artery disease*.
  • Left coronary-artery disease*.
  • Dyskinetic left ventricular wall motion.
  • Severe decrease in circulation to heart muscle.Taking these drugs may affect test results:
  • Beta-blockers*.Other factors that may affect test results:
  • Failure to follow pretest restrictions may hinder the heart’s ability to respond to stress. *See Glossary.

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