One of the most informative methods for examining the heart is scintigraphy (nuclear scanning). For the procedure, a medication containing radioactive isotopes (radionuclides) is used. The drug is injected into the patient’s body intravenously and, circulating with the bloodstream, is gradually absorbed by the heart muscle.
According to the degree of saturation of myocardial tissues with radionuclides, experts evaluate its functionality: active absorption indicates normal heart function, and vice versa, “empty” areas can indicate ischemia (death) of heart tissue.
Perfusion scintigraphy – a specific method for the diagnosis of coronary heart disease (CHD) is carried out using radioactive thallium. The procedure is performed with functional tests, and in contrast to conventional electrocardiography with physical activity, it allows you to most accurately determine the localization of the ischemic zone.
Further, the study is carried out in two stages: examination at rest and with a load on the heart. The received “signals” are captured by a gamma camera and converts them into statistical, dynamic and ECG-synchronized images. Myocardial scintigrams can be performed using:
- planar radionuclide research;
- SPECT (single photon emission computed tomography);
- PET (positron emission tomography);
- SPECT / PET, SPECT / CT, or PET / CT combinations.
They allow you to identify and determine:
- areas of myocardial ischemia, which is caused by damage to the coronary vessels;
- the size and location of the sites of myocardial infarction;
- the degree of violation of the blood supply to the heart;
- possible risks of complications.
There are two main ways to conduct research:
- Myocardial perfusion scintigraphy is a method for diagnosing coronary heart disease. For research, radioactive thallium is used. The method is considered more informative compared to electrocardiography, which is carried out under the influence of physical activity.
- With the use of vasodilating group preparations. The introduced drug allows you to expand the lumen of blood vessels and increase their patency. In places where there is a smaller accumulation of isotopes, the volume of blood flow will be weak, which will indicate pathology in these areas.
- What is scintigraphy done for?
- To each according to his needs.
- Heart scintigraphy study review, indications and contraindications
- How does it work?
- What does scintigraphy show?
- Myocardial scintigraphy for congenital heart defects
- Preparations for SGM
- Stress test
- The reasons for the incorrect result of the study
- Method Capabilities
- Risks and side effects of exposure
- Is the method safe?
- The essence of the method
- How to get to the study
Myocardial scintigraphy is a remote non-invasive
using radioactive particles. In fact, this is a record of the distribution of these isotopes in the body in the process of fixing their radiation.
Myocardial perfusion scintigraphy is essentially the same study as described above, but using radioactive thallium. It is made both with load tests, and without them. It allows you to accurately establish the focus of ischemia, which makes it indispensable in the diagnosis of coronary heart disease (coronary heart disease).
What is scintigraphy done for?
Myocardial scintigraphy helps detect coronary heart disease. Areas of ischemia are often difficult to determine during an ECG, especially with concomitant pathologies. Ultrasound of the heart also does not always help in the diagnosis of this disease. Nuclear-isotopic scanning helps to identify all areas that remain without power. This allows the doctor to determine the management tactics of the patient.
Myocardial scintigraphy is indispensable for identifying complications after acute conditions. A heart attack leaves behind non-functional areas, which are often difficult to determine on a cardiogram. In this case, myocardial scintigraphy will accurately show the “dead” zones of the heart muscle. It will also help identify areas that undergo ischemia. In these places, further destruction of heart tissue is possible.
Also, annual scintigraphy allows you to evaluate the effectiveness of the therapy, determine the need for surgical treatment. This method of examination is prescribed in cases:
- the first diagnosis of a patient with cardiovascular pathologies;
- as a preventive measure for people at risk;
- the need for a more accurate diagnosis if the symptoms are similar to other diseases;
- the selection of effective tactics for treating the patient and his recovery.
In addition, the procedure is assigned:
- if there is a need to assess the functioning of the left ventricle with altered ECG;
- to confirm or exclude the presence of angina pectoris;
- to establish the appropriateness of using certain therapeutic methods, such as coronary artery bypass grafting, angioplasty, stenting;
- in order to find out the reasons that contributed to the development of cardialgia.
Scintigraphy is necessary, because the choice of treatment methods and surgical intervention will depend on its results. The procedure can be carried out only on the recommendation of a cardiologist, when there is a need for:
- establishing the level of blood supply to tissues;
- general assessment of blood flow;
- detecting localization sites of cicatricial sites after a heart attack or foci of ischemia that lack oxygen and necessary nutrition during exercise.
To each according to his needs.
Since 2007, scintigraphy has become widespread in the United States, Western Europe and several other developed countries. This medical service has been used by more than fifteen million people. There it is a fairly routine procedure, which does not take much time and effort.
In the post-Soviet space, the situation is fundamentally different. At the moment, about two hundred gamma-ray scintigraphy cameras are in operation in Russia (compared with the American thirteen thousand). And they are available only at the level of highly specialized assistance.
Heart scintigraphy study review, indications and contraindications
Presence of a constant pacemaker in a patient
Not only medicines, but almost all diagnostic procedures carry a number of indications and contraindications to their behavior. Myocardial perfusion scintigraphy is no exception. Indications for rest scintigraphy (no load):
- Chest pain with an unexplained cause;
- Inability to perform physical activity, the patient has a constant pacemaker, as well as with blockade of the left leg of the bundle of His;
- Disorders in the work of the cardiovascular system, not accompanied by symptoms during other stress tests.
Despite the fact that perfusion scintigraphy without load is considered to be an uninformative method, in the above cases, the method can provide clarifying data regarding the patient’s diagnosis.
Assessment of the effect of vascular or valvular stenosis (narrowing) on regional blood supply
Scintigraphy with a load can be assigned:
- To establish the localization of lesions of the coronary artery;
- To assess the effect of vascular or valvular stenosis (narrowing) on regional blood supply;
- For the diagnosis of coronary artery disease without the presence of symptoms – with heart failure, atrial fibrillation, other rhythm disturbances;
- To assess the viability of the heart muscle;
- For differential diagnosis between cicatricial and ischemic changes in the heart muscle;
- After myocardial infarction;
- Before major surgical interventions on other organs and tissues in the presence of a high cardiovascular risk;
- To determine the risk assessment and prognosis of cardiovascular disease;
- To evaluate the effectiveness of treatment;
- With congestive heart failure;
- To assess the function of the left ventricle before using vital drugs that have a toxic effect on the heart muscle;
- To determine the feasibility of such treatment methods as angioplasty, stenting, coronary artery bypass grafting.
- Lactation. A woman is not allowed to feed her baby earlier than 48 hours after the study;
- MI in the last two days;
- Unstable angina pectoris with high cardiovascular risk;
- Violations of the rhythm, not amenable to treatment, leading to a violation of hemodynamics;
- Infectious diseases accompanied by fever;
- Acute heart failure;
- Narrowing of the aorta, accompanied by symptoms of severe heart failure;
- Uncontrolled arterial hypertension;
- Pulmonary embolism;
- Stratified aortic aneurysm;
- Acute inflammatory processes in the membranes of the heart – myocarditis, pericarditis, infectious endocarditis;
- Extracardiac severe disorders that may affect the test – severe renal failure, thyrotoxicosis;
- Severe emotional disorders, psychoses;
- The body weight of the patient is more than 120-130 kg.
Scintigraphy is a special method that allows you to study the circulation of blood in the coronary vessels by injection of radioactive isotopes that tend to accumulate in the myocardium. After that, a picture is taken showing the movement of radionuclides along the vascular walls of the heart. The picture determines the conductivity of blood flow, deficiency of blood supply to tissues.
The main advantage of the method lies in its information content and the possibility of repeated use during the day, since the drug is removed from the bloodstream for a long time.
Among the disadvantages of the method are:
- The need to exercise extreme caution when working with radiopharmaceuticals.
- The complexity of the method, which is important, since there are other methods that do not require impressive costs (ECG, ultrasound).
- Visualization of only pathological myocardium. Only a zone with an increased or low accumulation of a substance falls under registration. This may be an indicator of not only acute, but also chronic ischemia.
Myocardial scintigraphy is prescribed for patients with coronary heart disease already confirmed and for its establishment.
Indications for the application of the procedure:
- Identification of factors provoking pain in the sternum.
- Preventive examination of people at risk. It:
- those who have hypertension or diabetes;
- those with elevated cholesterol;
- persons over the age of 45 years (for the male half of the population), and from 55 for women;
- smokers with extensive experience in this area;
- people with a hereditary predisposition to heart pathologies.
- Inspection of people who engage in professional sports (the examination is carried out directly on the eve of the competition or training).
- Establishment of angina pectoris and heart attacks.
- Monitoring the patient’s condition and evaluating the effectiveness of the therapy.
- Operations or other surgical procedures performed on the heart.
Contraindications to scintigraphy:
- pregnancy and the period of breastfeeding;
- malfunctioning heart rhythms;
- severe heart failure;
- the patient’s body weight exceeds 120 kilograms;
- serious infectious diseases accompanied by high fever;
- aortic stenosis.
Before starting the procedure, the patient is introduced to the rules. He is told how to properly prepare for scintigraphy, the presence of all possible contraindications is revealed.
Preparation for the study is as follows:
- 24 hours before the start of the examination, you can not take products that contain caffeine, as well as cola and chocolate.
- It is recommended to refuse to take some medications, because of which the results of the examination may be incorrect.
- If the patient has contraindications, as well as a tendency to allergic reactions, it is necessary to tell the doctor in advance.
- The procedure is contraindicated in pregnant women. Before the study, you must make sure that there is no pregnancy.
- After scintigraphy, nursing mothers need to abandon breastfeeding for 48 hours.
- In the case of men taking Viagra and other similar drugs, you should also warn the doctor about this.
12 hours before the examination, you can’t eat at all. Patients with diabetes can eat only low-fat foods.
Myocardial scintigraphy is one of the expensive, but quite affordable methods. Prices will vary depending on the level of medical organization and the region.
For example, in the medical centers of Moscow the cost of a two-stage procedure is about 16 thousand rubles. Conducting scintigraphy only at rest costs in the range of 7500 rubles.
Where they do this procedure, the attending physician can tell.
Myocardial scintigraphy is also called a nuclear scan. This is a very effective method of radiation diagnostics in terms of information. It helps to evaluate the functioning of various organs and systems. The study enables doctors to identify errors in the blood supply to the heart, even during prevention and as soon as possible to detect pathology of the myocardium or blood vessels. When the problem is confirmed, this technique helps in the correction of therapy.
Myocardial scintigraphy is a non-invasive and painless procedure. When diagnosing a patient, a drug with radioactive isotopes is administered through a vein. A radioactive marker, along with blood, disperses throughout the body, penetrating, among other things, into the heart muscle. Gamma camera:
- fixes marker radiation;
- shows its distribution in the heart.
In which area of the myocardium there will be the highest marker concentration, there is a better blood flow and vice versa.
Active absorption of the drug means a normal state of blood supply, and in places of ischemia of the heart muscle its absorption is not expressed.
The gamma camera shoots, and all areas are clearly visible in the image. With perfusion scintigraphy of an organ, radio thallium is used. Myocardial scintigraphy (CM) is possible with a load or with samples. This technique detects coronary heart disease and is considered more sensitive than ECG. They can perform with physical loads.
During normal functioning of the body, this leads to increased blood flow in the coronary network, which saturates the heart muscle. However, in the presence of coronary heart disease during sports load, an increase in heart nutrition may not occur, or it will be scarce. Comparing the perfusion-type SM obtained in a calm state and under load, one can understand the whole clinic, make an analysis and find areas with coronary artery disease.
The essence of heart scintigraphy is that the gamma-ray scanner equipment captures radiation from isotopes introduced into the patient’s body. The model is transferred to the PC of the specialist who performs the examination. Myocardial scintigraphy with and without load is highly detailed in the procedure. Pathologies are determined at the earliest stages of formation. Thanks to the detail and informativeness of the study, it has spread to European and American clinics.
From this article you will learn: what is myocardial scintigraphy, according to what indications it is performed, and when it is contraindicated. Preparation, conduct and possible complications of this examination.
The author of the article: Nivelichuk Taras, Head of the Department of Anesthesiology and Intensive Care, work experience 8 years. Higher education in the specialty “General Medicine”.
Myocardial scintigraphy (abbreviated as SM) refers to cardiac imaging techniques that use a small amount of radioactive material to obtain an image. Other names for CM are scintigraphy of the heart, perfusion scanning of the myocardium.
This examination is one of the most effective methods for determining blood supply (perfusion) and viability of the heart muscle, allowing you to evaluate it both at rest and during exercise (physical or drug). The method is very common in the USA and Europe, but is rarely used in the countries of the former USSR, where infrequent SM testing is associated with the lack of modern equipment and the high cost of examination.
How does it work?
A patient prepared for the procedure is injected into the vein with a radio indicator drug that contains a vector molecule and radioactive isotopes. Their work is interconnected, since the vector has a chemical tropism (location) to a specific organ or tissue of the human body. And the isotope emits gamma radiation into the space around it. Registration of this type of waves allows you to determine the best and worst blood supply.
What does scintigraphy show?
Thanks to this visualization method, you can carefully view and evaluate the blood supply to the heart muscle, as a whole, and individual parts. To detect areas with insufficient blood flow, as well as to differentiate places where the heart tissue has died, from those that can still be saved. In post-infarction patients, scars and areas of ischemia are easily detected. In addition, the specialist can predict from the results of the study what complications should be expected and how soon.
Myocardial scintigraphy for congenital heart defects
Myocardial scintigraphy in children is carried out mainly to detect the discharge of the left coronary artery from the pulmonary trunk. 201T1 is administered iv at rest, after which scintigraphy in several projections or single-photon emission tomography is performed. With defect, a segmental violation of perfusion is detected.
This study allows us to differentiate the abnormal discharge of the left coronary artery and other causes of impaired myocardial contractility in infants – myocarditis and dilated cardiomyopathy. In addition, scintigraphy is performed to detect ischemia and myocardial infarction in Kawasaki disease.
The 67Ga gallium isotope selectively accumulates in the foci of acute and chronic inflammation of both bacterial and non-bacterial origin. Capture of 67Ga has been described in many inflammatory heart conditions, including infectious endocarditis, myocardial abscesses, and pericarditis.
In animal experiments, it was shown that 67Ga accumulates in the myocardium with myocarditis, and in clinical trials a strong relationship was established between the accumulation of 67Ga and morphologically confirmed myocarditis.
With morphologically confirmed myocarditis, scintigraphy with labeled antibodies to myosin has diagnostic value. With myocarditis, they accumulate in the foci of necrosis, in contrast to 67Ga, which is tropic to the foci of inflammation. Scintigraphy with 201T1 in myocarditis has been studied very little. Focal perfusion disorders were detected, which, however, did not correspond to the distribution of blood vessels.
Preparations for SGM
– MIBI, or sestambi, is used to study the work of the heart, has tropism to the heart muscle.
– Mono- and bisphosphonates have an affinity for bone tissue, are used to diagnose cancer and their complications, as well as injuries.
– Diethylenetriaminepentaacetic acid reveals kidney pathology.
– Pertechnates are used to examine the thyroid gland.
– Iodine-123 is intended for imaging of the thyroid gland.
Preparations have already appeared on the modern pharmacological market, thanks to which it is possible to diagnose specific forms of cancer. These substances are administered intravenously into the human body, so you need to find out in advance whether the patient has allergies.
As already mentioned, radionuclide Tc-99m is used for scintigraphy of the heart. Until such a preparation began to be used, the only substance was thallium-201. However, he had serious flaws. Preparations in which Tc-99m was used were devoid of such disadvantages.
Technetium is used by the radioisotope for two main factors:
- Almost 90% of the gamma rays emitted by it have an energy of 140 keV, and this is considered the ideal energy for a gamma camera.
- Technetium is very inexpensive compared to thallium.
In addition, the gamma rays emitted by Tc-99m are absorbed by soft tissues to such a high degree as thallium, therefore false positive accumulation defects due to the use of technetium in female patients and overweight are less common.
Another important advantage is a short half-life (6 hours). In the diagnosis of heart disease, four groups of drugs are used in which technetium is used as a radioactive label. Myocardial scintigraphy is based on the following:
Technetium pyrophosphate. Thanks to this drug, areas of necrosis that are formed due to myocardial infarction are visible.
When cells die, calcium slopes enter in large quantities into the cells, and microcrystals of calcium phosphates form.
In them, given technetium. However, this drug is used extremely rarely, since the area of necrosis becomes visible only two days after the occurrence of a heart attack, but after this time there is no doubt about the diagnosis.
Teboroxime This drug accumulates in the metabolically active tissue of the heart muscle.
It is quickly captured from the blood and excreted, in connection with which the drug is used only with gamma cameras, in which there are several detectors that make it possible to complete the examination before the moment when most of the Tc-99m leaves the heart muscle.
Myocardial stress scintigraphy is carried out in the same way as a similar study on electrocardiography. To create a stressful situation, the patient is offered to work out on simulators (treadmill, bicycle). Indications for such a procedure are reliable changes on the ECG, complaints characteristic of coronary heart disease. One of the difficult moments of the procedure is to obtain high-quality visualization of the left ventricle. The criteria for a positive test are:
- Left ventricular ejection fraction is not more than 35%.
- The increase in ejection fraction during intensive work by more than 5%.
- A reliable manifestation of a violation of contractility.
- Local disturbances in the contractility of cardiomyocytes with minimal load.
The reasons for the incorrect result of the study
Analysis begins with the upper part of the heart muscle with a gradual advance to the base. In assessing deviations are divided into defects of a transient or permanent nature. Compare shots at rest and under stress.
Emotional stresses are characterized by transient defects and are not detected in a calm state. Permanent changes do not occur, which will indicate the presence of a heart attack.
Analysis of the accumulation of radiopharmaceuticals is done using a quantitative scale from 0 to 3 points. Such a system makes it possible to accurately determine the complexity of the occurring violations. A radioactive agent tends to accumulate only in places of active metabolic processes, that is, in tissues not affected by ischemia.
The scheme used in the analysis of scintigraphy indicators:
- images are studied and images analyzed in three axes;
- do a quantitative analysis;
- determine the location of defects in relation to the heart;
- assess the viability and establish the degree of damaged areas of the myocardium.
Among the factors that can distort the results of the examination, there are:
- increased tendency of tissues to absorb radionuclides;
- large mammary glands;
- high location of the diaphragm of an innate nature;
- a lot of subcutaneous fat.
Sometimes it happens that the result shows a positive, but in fact, the reasons are completely different. This may be due to various factors. But the main reasons that lead to a false positive result when myocardial scintigraphy is performed are as follows:
- a large body weight of the patient is provoked by obesity, as a bad image is obtained due to the large amount of fat;
- the large size of the mammary glands, which also in turn close the review of the equipment;
- too high aperture placement, which also creates a shutter for viewing pictures of the movement of isotopes;
- the presence of a tendency to accumulate, which leads to the fact that the substance is poorly excreted from the body and remains with each subsequent study, distorting the result.
Cardiac examinations, such as myocardial scintigram, always require attention and a very responsible attitude. Therefore, it is important to know how to prepare for it in order to get accurate results.
Myocardial scintigraphy allows you to get several types of images of the heart muscle. Firstly, these are still, so-called static, shots. This is a two-dimensional (flat) image of an organ. Most often in this way they examine bones, endocrine glands, etc.
Secondly, there are dynamic or moving images that allow you to evaluate the work of hollow organs. They are obtained as a result of combining several still pictures. They are used to examine the liver, kidneys, heart, blood vessels.
The third type of registration of the study is ECG synchronization. Additional removal of the cardiogram allows you to compare the function and topography of organ damage.
Some specialists, when performing myocardial scintigraphy, also connect SPECT (single-photon emission computed tomography) to obtain three-dimensional images of the organ under investigation. Often this is done if a pathology of the heart or brain is suspected.
Decoding myocardial scintigraphy
Having received a series of myocardial images at rest and with a load, the functional diagnostics doctor performs a visual assessment using polar maps. Next is the computer processing of images with the calculation of the concentration of substances in various parts of the myocardium. A weak accumulation of a radioactive substance in a particular area indicates the presence of an ischemic zone.
- Increased tendency of body tissues to absorb radioactive isotopes;
- Large sizes of mammary glands;
- High standing diaphragm congenital;
- Pronounced subcutaneous fat.
Using scintigraphy, doctors can determine errors in the blood supply to the myocardium even at a routine examination and identify the problem in time.
If the problem already exists, this diagnostic method helps to adjust the treatment to achieve its maximum effect.
Among other options for this non-invasive study is myocardial scintigraphy. During this procedure, a substance with radioactive isotopes is injected into a subject through a vein.
A radioactive marker along with the bloodstream spreads throughout the body, including in the myocardium. A gamma camera that captures marker radiation shows its distribution in the heart muscle.
In which area of the myocardium there will be a high concentration of the marker, there is better blood flow and vice versa.
The gamma camera takes pictures where all these areas are clearly visible.
With perfusion myocardial scintigraphy, radioactive thallium is used. Myocardial scintigraphy is possible with a load or with samples. This method of determining coronary heart disease is more sensitive compared to electrocardiography, also performed with physical activity. With its help, you can more accurately find the position of the focus of ischemia.
With physical activity of a person, the heart is forced to work more intensively, therefore, it itself needs additional oxygen and nutrition. Normally, this leads to increased blood circulation in the coronary network that nourishes the heart.
But in the presence of ischemia during exercise, an increase in the nutrition of the heart muscle may not occur, or it will be insufficient.
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Using myocardial scintigraphy, you can:
- determine the degree of circulatory failure;
- generally evaluate coronary blood supply to the myocardium;
- visualize foci of ischemia that occur during exertion, and scar tissue at the site of a heart attack;
- to differentiate zones with insufficient circulation from already undergone necrosis;
- assess the possibility of complications.
The results will affect the treatment tactics and planning of surgical intervention.
Thanks to scintigraphy, it is possible to understand the degree of blood filling of any cardiac chamber and identify the exact places where the heart begins to malfunction due to a violation of blood supply. Most often, this study is combined with treadmill tests and bicycle ergometry as an exercise stress.
Indications for myocardial scintigraphy are as follows:
- to identify angina pectoris;
- when there are changes in the ECG or symptoms of heart disease;
- to evaluate the work of the left ventricle;
- for prophylactic diagnosis among risk groups for cardiovascular diseases (before invasive procedures, surgical operations, sports);
- to assess the risk of possible complications;
- to find out the causes of chest pain;
- to assess the functionality of the heart muscle after suffering an MI;
- to determine the success of drug therapy, angioplasty, coronary bypass surgery;
- for the diagnosis of coronary heart disease (this is one of the best methods for the study of IHD) and the study of its contractile potential.
At the same time, scintigraphy can be equally useful both at the stage of diagnosis of coronary circulation disorders, and with already confirmed diagnoses.
After all, with the help of it you can more accurately assess the degree of ischemia and choose a more appropriate treatment tactic.
For example, when a diagnosis is made using computed tomography or catheterization, a scintigraphy is prescribed that will shed light on the need for surgery for the coronary vessel.
Despite its effectiveness, scintigraphy has contraindications:
- excessive obesity (body weight over 120-130 kg);
- general infections accompanied by fever;
- severe ailments that do not allow to load the cardiovascular system;
- high and uncontrolled blood pressure;
- severe heart failure or acute myocardial infarction;
- severe cardiac arrhythmia and heart valve defects (especially aortic stenosis).
Risks and side effects of exposure
The radioactive drug TC-99m-MIBI causes a very low dose, which is the same value as in conventional radiography. Your attending physician carefully weighs the risks and the fact that the research method in this particular case is the most profitable and least stressful.
This is important for the accuracy and completeness of the results that you can achieve at the highest possible load. In only one case out of 10.000 – 20.000 examinations, a cardiac arrhythmia problem may require treatment or a heart attack can be expected (probability of an attack is 1: 40000).
If the stress test on the bicycle ergometer fails, for example, with orthopedic diseases, then the load can be simulated artificially using a special drug that is injected into a vein on the arm.
During a stress test, your stress ECG is also monitored. Emergency equipment, of course, is available.
Is the method safe?
In order to undergo such a functional examination as perfusion scintigraphy, the patient must have certain indications, as well as be prepared for the study. Perfusion scintigraphy is performed on an empty stomach. A few days before the procedure, it is not recommended to use caffeinated products (coffee, chocolate, tea, caffeinated drinks).
A radiopharmaceutical drug (thallium or tetrophosmin labeled with technetium) is administered intravenously to the patient, which, in combination with a special substance, is able to quickly spread across the myocardium. The introduced radioactive substance accumulates only in healthy tissues, not lingering in areas affected by pathological processes.
Scintigraphy with a load can be of two types:
- Exercise stress. To do this, use a treadmill (treadmill test) or bicycle ergometry (bicycle).
- Medication load. If, for certain reasons, the patient cannot perform physical activity, drugs that stimulate the heart are used – dobutamine, adenosine, etc.
During the load, the cardiovascular parameters (pulse, heart rate, blood pressure) are monitored. At maximum physical load, a radiopharmaceutical is administered to the patient. Next, using a gamma camera, a series of pictures is taken.
Perfusion scintigraphy is a non-invasive diagnostic method, painless and safe for the patient. Radioactive substances are administered in small doses, have a short half-life and are rapidly excreted from the body. The most common side effects on an administered drug are allergic reactions. However, the diagnostic value of the method significantly exceeds the possible side effects.
– pregnant and lactating mothers;
– people with severe diseases of other organs and systems (this can create problems during the study using the load);
– patients with sepsis and fever;
– with myocarditis, the presence of heart defects and after a recent heart attack.
The method itself is painless and almost harmless. Sometimes patients experience side effects from medications or physical exertion, but, as a rule, the discomfort quickly passes, and people return to normal life.
They allow you to make a detailed picture of many diseases of this vital organ, but in some cases, a diagnostic procedure such as myocardial scintigraphy can supplement the informativeness of these methods of examining a patient with pathologies of the cardiovascular system.
In this article, we will introduce you to the essence, indications and contraindications, methods of preparing and conducting myocardial scintigraphy. This information will be useful for you, you can understand the principle of such a diagnostic procedure and ask your doctor your questions.
After that, experts use a gamma camera that records the degree of saturation of myocardial cells with these radionuclides. The data obtained allows doctors to evaluate the functionality of the heart muscle.
Normally working sections of the myocardium actively absorb such label preparations, and those suffering from ischemia or necrosis, on the contrary, are not capable of sufficient accumulation of these funds.
The essence of the method
A patient is injected with a radioactive drug into a vein, which, with a blood stream, spreads throughout the body and accumulates in the heart. Then, using a gamma camera, experts examine the degree of its accumulation in each of the structures of this organ.
The principle of performing myocardial scintigraphy is in many ways similar to stress echocardiography, which assesses the functioning of the heart muscle at rest and after physical exertion (for this, the patient receives a load on an exercise bike or treadmill). With scintigraphy, at the beginning of the study, a radionuclide preparation, a luminous radioactive label Tc-99m-MIBI or thallium-201, is injected into the patient’s vein.
It spreads with the flow of blood to the heart and accumulates in the myocardium, emitting gamma rays. After that, the degree of its accumulation is recorded using a gamma camera.
The study is carried out for 2-4 hours, and during this time, specialists study the state of the myocardium at rest and after exercise. A gamma camera captures signals from radiation areas and converts them into a series of dynamic, static and ECG-synchronized images.
Myocardial scintigraphy can be performed using:
- planar radionuclide research;
- single photon emission computed tomography (SPECT);
- combined methods: PET / CT, SPECT / CT or SPECT / PET.
Myocardial scintigraphy can be used not only to identify the disease, but also provides an opportunity to evaluate the effectiveness of the applied treatment methods:
- surgical and endovascular interventions: stenting, coronary artery bypass grafting, angioplasty;
- drug therapy;
- rehabilitation measures.
To obtain myocardial scintigrams, the following groups of drugs are used:
- Technetrile or Sestamibi (based on methoxy-isobutyl-isonitrile). These drugs accumulate in the metabolically active myocardial tissue and remain there for a long time. After accumulation, they can be fixed with a gamma camera and give specialists the opportunity to assess the condition of different sections of the heart muscle.
- Miowu (based on tetrophosmin). This new generation radionuclide is similar in its properties to previous preparations based on methoxy-isobutyl-isonitrile, but has a number of significant advantages. After accumulation in the tissues of the myocardium, it is not redistributed over time and is more rapidly excreted from the body by the liver.
- Teboroxime The drug, like methoxy-isobutyl-isonitrile-based products, accumulates in the metabolically active myocardial tissue. However, it is rapidly displayed and can only be used with gamma cameras that are equipped with detectors that allow examination even before most of the technetium leaves the heart muscle cells.
- Technetium pyrophosphate. Thanks to this radionuclide tag, it is possible to identify areas of myocardial necrosis provoked by a heart attack. After the death of cardiomyocytes (heart muscle cells), microcrystals of calcium phosphates are formed in them. They accumulate technetium, and its rays are captured by a gamma camera. This radionuclide preparation is used extremely rarely, since the zone of necrosis after its administration can be detected only after 24-48 hours.
- Thallium 201. This drug is less commonly used to perform perfusion myocardial scintigraphy, because it is inferior in its quality to technetium-based radionuclide agents.
Myocardial scintigraphy may be recommended for patients with heart pain to identify their causes.
Myocardial scintigraphy can be prescribed in the following cases:
- identification of the causes of cardialgia;
- cardiac ischemia;
- myocardial infarction or the need to assess the state of the myocardium after a heart attack;
- study of the contractility of the heart muscle;
- examination of patients who have been prescribed an invasive procedure or surgery on the coronary vessels or heart;
- monitoring the effectiveness of treatment (postoperative, medication or rehabilitation);
- examination of athletes before intense training or competition;
- preventive examination of people at risk of developing coronary heart disease: patients with hypertension, high cholesterol or diabetes mellitus, predisposing to coronary heart disease, smokers, women over 55 years old and men over 45 years old.
An absolute contraindication to performing myocardial scintigraphy is pregnancy. In addition, the procedure cannot be performed for patients with a body weight of more than 120-130 kg, since the installation of a radionuclide tomograph will not be able to withstand such a weight.
During breastfeeding, myocardial scintigraphy can be prescribed only in exceptional cases, when the importance of its conduct exceeds all possible risks. Under such circumstances, a woman is recommended to express milk and store it in the refrigerator until the procedure is completed.
It cannot be used to feed a baby for 48 hours.
With other relative contraindications, after stabilization of the patient’s condition, scintigraphy can be performed. This decision is made after studying all the data of diagnostic studies confirming the safety of the procedure.
Before scintigraphy, the doctor will ask the following questions:
- what preparations the patient takes (after that he can give recommendations on the temporary cancellation of some of them, for example, cardiac glycosides, Viagra, Levitra, etc.);
- Does he suffer from bronchial asthma;
- whether the woman is of childbearing age (an ultrasound or test is performed to exclude such a contraindication).
How to get to the study
Where to do myocardial scintigraphy? First of all, it is necessary to undergo an examination in a clinic or in a therapeutic hospital to determine if there is a need for such an expensive study. Many heart diseases can be detected by more accessible methods.
As mentioned above, in the post-Soviet space, the opportunity to conduct such testing is available only in large cities. Myocardial scintigraphy in Moscow is carried out in several private clinics, as well as in the Scientific and Practical Center for Interventional Cardiology, in the Research Institute of Gerontology of the Ministry of Health of the Russian Federation, and the Scientific Center for Cardiovascular Surgery. A. N. Bakuleva and in the department of radiation diagnostics of the Clinical Center MMA named after I.M.Sechenova.
Pricing policies in public and private hospitals can vary, sometimes even quite significantly. Therefore, it makes sense to carefully study the services that a particular hospital offers and then it is already up to you to decide on the requested amount for such a study as myocardial scintigraphy. The price in Moscow may vary depending on the volume of the procedure and the venue.
The cost is somewhere in the region between seven and eight thousand rubles. This is for simple research only. But there are patients who require myocardial scintigraphy with exercise. Its price will be at least twice as high. From fifteen thousand rubles, respectively. However, this method gives the doctor a more complete picture of the patient’s health status, and also helps to choose the optimal therapeutic tactics.
Myocardial scintigraphy is a relatively new, non-invasive, safe and painless way to examine the heart muscle. By combining the achievements of modern computer technology and discoveries in the field of radioactive substances, it has become possible to diagnose coronary artery disease in the very early stages.
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