In our age of high technology, medicine is trying to keep up with the times and is developing new ways to examine the human body. The main criteria are high information content, safety, ease of use and low cost. One of these methods is lung scintigraphy. The indications for this procedure are quite wide, so it is used by both therapists and surgeons. This allows you to determine the tactics of treatment and accurately localize the problem area.
Lung scintigraphy: what is it?
Scintigraphy is a method of radiation diagnostics used to assess the function of human organs and tissues. It involves injecting radioactive isotopes into the bloodstream and obtaining an image by recording the radiation they emit. The procedure itself is carried out using specific equipment that can capture radiation and visualize it.
Lung scintigraphy is performed to study the circulatory system of the lungs and detect ventilation disorders. As a rule, blood clots or emboli are eventually found, which disrupt the normal outflow of blood. During the procedure, you maytwo methods of assessing the state of the organ are used, depending on what tasks are set for the doctor:
- ventilation;- perfusion.
Ventilation and perfusion scintigraphy
Ventilation scintigraphy is needed to assess respiratory function, it shows the flow of air into the respiratory system. To do this, the patient is asked to inhale an aerosol that contains radioisotopes, and then using a gamma camera to monitor their progress in the body. Cold areas indicate that the aerosol did not enter there. The doctor may suggest possible causes of this phenomenon: stenosis, swelling, fluid, or atelectasis.
Perfusion lung scintigraphy for PE and other circulatory diseases allows you to visualize the vessels of the lungs and see the flow of blood from the right ventricle through the pulmonary arteries. Before scanning, the patient is injected intravenously with Technetium-99, which decays into smaller isotopes, and the radiation from this process is recorded by a gamma camera. If a site is found in the organ where no radioactive substance has entered, then it is most likely that the lumen of the vessel is blocked by an embolus or thrombus.
Indications for the procedure
When is a lung scintigraphy scheduled? Indications - thrombophlebitis of deep veins of the lower extremities, diagnosis of pulmonary embolism and dynamic monitoring of its treatment, identification of the causes of pulmonary hypertension and much moreother. In addition to vascular problems, scintigraphy can determine the functional state of the lungs before a long operation, check for interstitial lung diseases, as well as the presence of congenital diseases of the lungs and heart. Physicians prescribe pulmonary scintigraphy to exclude or confirm chronic obstructive pulmonary disease and heart failure, emphysema, pulmonary infarction, cancer.
Contraindications
Lung scintigraphy does not require any specific preparation from the patient, unlike most invasive procedures such as transesophageal echocardiography or bronchoscopy.
But before the procedure, it is imperative to conduct allergy tests with the radioactive substance that will be used in the study. This is necessary in order to avoid an attack of anaphylaxis at the moment when the patient is inside the gamma chamber. Stopping an allergic reaction is much more difficult than preventing it.
If a woman is examined, she must be examined by a gynecologist to rule out a possible pregnancy, or inform the doctor that the baby is breastfed, since radioisotopes will get into all liquids, including milk.
It is strongly not recommended to take barium or bismuth preparations less than four hours before the procedure, as this may affect the results of the study.
Scintigraphy process
According to reviews, a lung scan takes only twenty minutes. In order to conduct a perfusion study, the patient is asked to take a vertical position (this way the image will turn out better). The patient is injected intravenously with a drug that contains radioactive isotopes, and they immediately begin scanning to see the progress of the particles in the blood. They are so small that they will fall into even the narrowest vessels.
When performing a ventilation scintigraphy, the patient inhales an aerosol until the gases in the lungs are in equilibrium. The radioactive particles begin to decay, and the camera can pick up radiation from areas where the gas has entered. If, after these two methods, an area was found where there is a perfusion defect, but ventilation remained normal, then most likely the patient has a pulmonary embolism.
Complications
If a person is not allergic to isotope markers, then he will experience pain and discomfort only when the skin is pierced. During the study, the patient's well-being should be satisfactory. Nausea, headache, dizziness are abnormalities that should be reported to the doctor immediately.
Do not be afraid of radioactive radiation either, because it is several times less than the same during computed tomography or magnetic resonance imaging. Of course, it cannot be said that the study is completely safe, but scientists are working on these issues to this day.
Reviews indicate: sometimes it happens that the results of lung scintigraphy can be interpreted from different points of view. ATIn such cases, pulmonary angiography is necessary to confirm the diagnosis. Under the control of computed tomography, a contrast agent is injected into the patient's bloodstream (usually after pulmonary artery catheterization), which moves through the vessels of the lungs, filling all the available space. Then a series of snapshots of the lungs in dynamics is taken. If the doctor notices an area where there is no vascular pattern, then most likely this is where the embolus is located.
Patients say lung scintigraphy is informative, painless and reliable.
