La lung scintigraphy is a test that looks at the distribution of air and blood in the lungs and diagnoses a pulmonary embolism. We also speak of pulmonary scintigraphy of ventilation (air) and perfusion (blood).

Scintigraphy is a imaging technique which consists in administering to the patient a radioactive tracer, that spreads in the body or in the organs to be examined. Thus, it is the patient who “emits” the radiation that will be picked up by the device (unlike radiography, where the radiation is emitted by the device).

This test is used in case of suspected pulmonary embolism, to confirm or deny the diagnosis.

Pulmonary embolism is caused by a blood clot (thrombus) which suddenly obstructs a pulmonary artery. The signs are not very specific: chest pain, malaise, dry cough, etc. Left untreated, embolism can be fatal in 30% of cases. It is therefore a medical emergency.

To confirm or rule out the diagnosis, doctors may use imaging tests, especially CT angiography or lung scintigraphy.

This examination can also be prescribed:

• a cas de chronic lung disease, to evaluate the effectiveness of a treatment or to follow the evolution;
• to take stock in the event ofunexplained shortness of breath.

Lung scintigraphy does not require special preparation and is painless. However, it is essential to inform the doctor of any possibility of pregnancy.

Before the examination, the medical staff injects a slightly radioactive product into a vein in the patient’s arm. The product is coupled to protein aggregates (albumin) which will lodge in the pulmonary vessels, which allows them to be visualized.

To take the pictures, you will be asked to lie down on an examination table. A special camera (gamma-camera or scintillation camera) will move quickly above you: you will have to breathe a gas using a mask (radioactive krypton mixed with oxygen) to allow you to also visualize the pulmonary alveoli. In this way, the doctor can observe the distribution of air and blood in the lungs.

It is enough to remain motionless for fifteen minutes during the acquisition of the images.

After the examination, it is advisable to drink plenty of water to facilitate the elimination of the product.

Lung scintigraphy can reveal abnormalities of the air and blood circulation in the lungs.

Depending on the results, the doctor will suggest appropriate treatment and follow-up. In case of pulmonary embolism, urgent care is required, where you will be given a anticoagulant treatment to dissolve the clot.

Other examinations may be necessary to obtain more information (x-ray, CT scan, PET scan, functional respiratory examinations, etc.).