In our age of high technology, medicine is trying to keep up to date and is developing ever new ways of examining the human body. The main criteria are high information content, safety, ease of use and low cost. One such technique is lung scintigraphy. 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 radiation diagnostic method used to evaluate the function of human organs and tissues. It includes the introduction of radioactive isotopes into the circulatory system and obtaining an image by recording the radiation that they emit. The procedure itself is carried out using specific equipment that can capture radiation and visualize it.
Lung scintigraphy is performed to examine the circulatory system of the lungs and detect ventilation disorders. As a rule, blood clots or emboli that interrupt the normal outflow of blood are eventually found. During the procedure, two methods can be used to assess the state of the organ, depending on what tasks the doctor has:
- ventilation;
- perfusion.
Ventilation and perfusion scintigraphy
Ventilation scintigraphy of the lungs is needed to assess respiratory function, it shows the flow of air into the respiratory system. For this, the patient is offered to inhale an aerosol that contains radioisotopes, and then with the help of a gamma camera they monitor their progress in the body. Cold areas indicate that aerosol did not enter there. The doctor may suggest possible causes for this phenomenon: stenosis, swelling, fluid or atelectasis.
Perfusion scintigraphy of the lungs with pulmonary embolism and other diseases of the circulatory system allows you to visualize the blood vessels of the lungs and see the flow of blood from the right ventricle through the pulmonary arteries. Before scanning, the patient is injected with Technetium-99, which disintegrates into smaller isotopes, and a gamma camera detects radiation from this process. If a site is found in the organ where the radioactive substance has not arrived, then it is most likely that the lumen of the vessel is blocked by an embolus or thrombus.
Indications for the procedure
When is lung scintigraphy prescribed? Indications - deep vein thrombophlebitis of the lower extremities, diagnosis of pulmonary thromboembolism and dynamic monitoring of its treatment, identification of the causes of pulmonary hypertension and much more. In addition to vascular problems, using scintigraphy, you can determine the functional state of the lungs before a long operation, check for interstitial lung diseases, as well as the presence of congenital lung and heart diseases. Therapists prescribe lung scintigraphy to rule out or confirm chronic obstructive pulmonary disease and heart failure, emphysema, pulmonary infarction, and 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 absolutely necessary 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 a time when the patient will be inside the gamma camera. Stopping an allergic reaction is much more difficult than preventing it.
If a woman is examined, then she must undergo an examination by a gynecologist to exclude a possible pregnancy, or inform the doctor that the baby is breastfed, since the radioisotopes will get into all fluids, including milk.
It is highly recommended that barium or bismuth preparations be taken less than four hours before the procedure, as this may affect the results of the study.
Scintigraphy process
According to reviews, lung scintigraphy takes only twenty minutes. In order to conduct a perfusion study, the patient is asked to take an upright position (so the image will turn out better). The patient is injected intravenously with a drug that contains radioactive isotopes, and immediately begin scanning to see the progress of particles in the blood. They are so small that they will fall even into the narrowest vessels.
During ventilation scintigraphy, the patient inhales an aerosol until a balance of gases is established in the lungs. Radioactive particles begin to decay, and the camera can catch radiation from those areas where the gas has got. If after these two methods a site was found where there is a perfusion defect, but ventilation remained normal, then most likely the patient has pulmonary embolism.
Complications
If a person is not allergic to isotope markers, then he will experience pain and discomfort only when piercing the skin. During the study, the patient's well-being should be satisfactory. Nausea, headache, dizziness are abnormalities that are best reported to the doctor right away.
Do not be afraid also of radioactive radiation, because it is several times smaller than the same during computed tomography or magnetic resonance imaging. Of course, it cannot be argued 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. In such cases, to confirm the diagnosis, angiopulmonography is necessary. Under the control of computed tomography , a contrast medium is injected into the patient’s bloodstream (usually after catheterization of the pulmonary artery), which moves along the vessels of the lungs, filling all available space. Then a series of lung shots in dynamics is taken. If the doctor notices a site where there is no vascular pattern, then most likely the embolus is located there.
Patients say lung scintigraphy is an informative, painless, and reliable diagnostic method.