Pulmonary Perfusion Scintigraphy
The lung scintigraphy or pulmmonary scintigraphy is a special examination of the blood flow and ventilation conditions of the lung. The most common reason for performing a lung scan is the suspicion of a pulmonary embolism (vascular occlusion in the lungs).
Other names: Pulmonary Perfusion Scintigraphy
Used contrast agents: Technetium Tc-99m MAA
What is a lung scintigraphy?
The lung scan (Pulmonary Perfusion Scintigraphy) is a nuclear medical examination procedure for assessing the pulmonary blood flow (perfusion) in which the regional blood flow ratios of the lungs are imaged to be calculated regionally (quantify).
When is this examination needed (indication)?
The main indication is a pulmonary embolism, which is a life-threatening disease. In approximately 20% of patients who die in the hospital, acute pulmonary embolism is the immediate cause of death. A pulmonary embolism means that threatening closures of pulmonary vessels occur. This results in a reduced oxygen uptake of the blood and a heavy load to the heart. With the help of a pulmonary perfusion scintigraphy the blood flow to the lungs is captures and the results of the vascular occlusion is presented.
Other indications for performing a pulmonary perfusion scintigraphy is the assessment of the lung function prior to elective lung surgery (e.g. lung cancer), the calculation of blood flow changes in the context of cardiac and pulmonary circulation in congenital anomalies of the lungs.
How is the examination performed?
A small amount of a slightly radioactive substance is injected into the bloodstream or into a vein in the arm; it settles in the pulmonary vascular bed and accumulates in the perfused lung areas. This makes it possible to show in particular the blood circulation and also small pulmonary vessels. Moreover, the extent of circulatory disorders in pulmonary embolism can be determined particularly well. In lung areas that are no longer supplied with blood, there is no accumulation.
During the test, the patient lies on his back, as still as possible, on an examination table. With a gamma camera single images are then made from different perspectives (so-called planar images), different individual images of lung sections taken (images of the front, back, and special images of the side). If necessary, an additional tomographic may be required (so-called SPECT). The test period may be about 20 to 40 minutes.
Are special preparations necessary?
No special preparation is required for this examination. The patient does not have to fast prior to coming to the clinic. Medication does not affect the examination and can be taken the same day.
Are there side effects?
The injection might in rare cases cause an allergic reactions since the radiation marked substance includes protein components. Such effects are, however, easy to control.
When should the examination not be performed (contraindications)?
A relative contraindication is a pregnancy or breast-feeding, and a known intolerance or allergy to medications.
How high is the radiation exposure?
Since the substance is only a weak radioactive substance, the examination involves only a low radiation dose, such as in a normal X-ray examination.
Who pays for the examination?
The pulmonary scintigraphy is a standard benefit afforded all patients of statutory and private health insurances.