What procedure is done when finding a pulmonary embolism?

A pulmonary embolism (PE) can be diagnosed through various imaging tests, one of which is a ventilation-perfusion (V/Q) scan. Here's a general overview of the procedure involved in a V/Q scan:

1. Preparation:

- The patient may be asked to avoid certain medications or supplements that can affect the accuracy of the scan.

- A small amount of radioactive dye (radiopharmaceutical) is prepared.

2. Ventilation Scan:

- The patient is positioned on a scanning table, usually lying on their back.

- A technician or radiologist will provide the patient with a mouthpiece or face mask.

- The patient is asked to breathe in a gas that contains a radioactive isotope, such as technetium-99m (Tc-99m). This gas is inhaled and distributed throughout the lungs.

- A gamma camera, which detects the emitted radiation, captures images of the lungs as the radioactive gas is distributed.

- The ventilation scan provides information about the airflow and ventilation in the lungs.

3. Perfusion Scan:

- After the ventilation scan, the patient is still positioned on the scanning table.

- A small amount of the radioactive dye is injected into a vein in the arm, usually through an IV. This dye travels through the bloodstream to the lungs.

- Similar to the ventilation scan, the gamma camera captures images of the lungs as the radioactive dye flows through the blood vessels.

- The perfusion scan provides information about the blood flow to different regions of the lungs.

4. Image Interpretation:

- The images obtained from both the ventilation and perfusion scans are analyzed by a radiologist or nuclear medicine specialist.

- Areas with absent or reduced ventilation (seen on ventilation scan) but with preserved perfusion (seen on perfusion scan) may indicate a PE.

- The radiologist compares and interprets the patterns seen on both scans to identify any abnormalities or blockages that could suggest the presence of a pulmonary embolism.

5. Results and Diagnosis:

- The radiologist prepares a report based on the findings of the V/Q scan.

- The results are typically shared with the ordering physician, who then discusses the findings and any further steps with the patient.

- Depending on the findings of the V/Q scan, additional tests or procedures may be recommended for confirmation or further evaluation of the suspected pulmonary embolism.

It's important to note that a V/Q scan may not always be sufficient for a conclusive diagnosis, and the interpretation of the results should be done by a healthcare professional in the context of the patient's overall clinical presentation and other relevant information.