040-68334455
By Dr Govinda Reddy Karri
Consultant Radiologist
What is a V/Q scan? What is the need of a V/Q scan? What happens during a V/Q scan? Important information Faqs

V/Q scan

What is a V/Q scan?

Two imaging tests are combined into a V/Q scan to search for specific lung issues. Tests include:

  • A ventilation scan that counts the amount of air entering and leaving your lungs.
  • A perfusion scan that measures the blood flow (how blood flows in the lungs)

You can do the two scans independently or simultaneously.

A tracer, a tiny quantity of which is used in a V/Q scan, is used to look for illness in the body. The scans aid in diagnosing a pulmonary embolism, among other lung problems (PE). A PE is a potentially fatal obstruction in a lung artery. It often occurs when a blood clot that is lodged in another body organ escapes and moves to the lungs.

Other names: Other names of this test are ventilation/perfusion scan, pulmonary ventilation/perfusion scan, lung scan, lung V/Q scan

What is the use of V/Q scan?

The most frequent purpose of a V/Q scan is to look for pulmonary emboli (PE). It can also be used to:

What is the need of a V/Q scan?

If you experience pulmonary embolism symptoms, you could require a V/Q scan (PE). These consist of:


Many people with PE don't have symptoms. But doctor may order a V/Q scan based on a physical exam and if you have certain risk factors such as:

  • Long periods of inactivity or prolonged sitting (such as from long car trips or flights), bed rest.
  • Family history of blood clots or PE
  • Recent surgery
  • Older age
  • Obesity
  • Smoking

One might also be at higher risk if you have:

What happens during a V/Q scan?

V/Q scans are often carried out at a radiology office or a medical facility. A ventilation scan, a perfusion scan, or both scans might be performed on you. If you're receiving both, the scans will be performed back-to-back.

For both scan types:

  • On a special table, you will remain perfectly motionless while the scanner collects images of your lungs.
  • You will be given a material known as a radioactive tracer before to the scan. Gamma rays, a kind of energy, are released by the tracer. The scanner gathers the rays to produce pictures of your lungs.

For both scan types:

  • On a special table, you will remain perfectly motionless while the scanner collects images of your lungs.
  • You will be given a material known as a radioactive tracer before to the scan. Gamma rays, a kind of energy, are released by the tracer. The scanner gathers the rays to produce pictures of your lungs.

A ventilation scan:

  • You will wear a face mask and inhale a gas containing the radioactive tracer.
  • While you are holding your breath, a healthcare expert will use a scanner to capture photographs of your lungs.
  • While you breathe in the tracer gas for a few more minutes, your provider will continue to take images.
  • Your face mask will be removed after the tracer gas has gathered in your lungs. The tracer will exit your lungs when you breathe normally.

A perfusion scan:

  • Through an intravenous (IV) line, a medical professional will inject the radioactive tracer into your vein.
  • The tracer will build up in the lungs' blood arteries.
  • The scanner will be used by your doctor to obtain images of your lungs.
  • Throughout the examination, you will be moved around so that the scanner may take pictures of your lungs from various perspectives.

Will there be anything I need to do to get ready for the test?

Generally, a V/Q scan comes after a chest x-ray. Doctor will inform about all preparation you need.

Is there any risk associated with the test?

  • In a V/Q scan, there is hardly any radiation exposure. The radioactive material is used sparingly, and all of the radiation quickly exits the body.
  • While a V/Q scan's radiation dose is generally safe for humans, it can be dangerous for an unborn child. So make sure to inform your healthcare professional if you are pregnant or suspect you may be pregnant. Additionally, let your healthcare professional know if you are nursing since the tracer may contaminate the milk.
  • During a perfusion scan, you could feel slightly uncomfortable as the tracer is administered.
  • Allergies to the tracer are uncommon and typically minor.

What do the findings imply?

If your ventilation and perfusion scan results are abnormal, you may have a pulmonary embolism (PE) and require immediate medical attention. The scans may also reveal that you have a different lung ailment. These are some examples:


Important information to know about a V/Q scan?

If you are diagnosed with a pulmonary embolism (PE), your treatment may include medicines such as blood thinners, which help prevent clots from forming, or clot busters, which help dissolve clots quickly.
If the medicines don't work, or you have a very large clot, you may need a surgical procedure to prevent and remove the clots.

Frequently Asked Questions

1. What is a VQ scan used for?

A VQ scan can help to diagnose a blood clot in the lungs.

2. Can a VQ scan detect lung disease?

Yes, a V/Q scan helps to diagnose different lung conditions, such as pulmonary embolism (PE).

3. How long does it take for a VQ scan to complete?

The examination lasts between 30 and 45 minutes. The test consists of two parts: breathing and injection. For the breathing section, you will be asked to breathe in and out via a tube put in your mouth while your nose is clamped shut.

4. Is pulmonary hypertension detected by a VQ scan?

Yes, a VQ scan is the preferred test for distinguishing CTEPH from other forms of pulmonary hypertension (PH).

5. What precautions should be followed after a VQ scan?

For the next 24 hours, avoid prolonged close contact with pregnant women and children. Children and pregnant women are not permitted to accompany you to the department. During this period, you should also avoid blood tests and dental checkups.

6. Do you need a chest x-ray before a VQ scan?

Yes, a chest x-ray is usually done before or after a ventilation and perfusion scan.

7. What are the signs and symptoms of pulmonary hypertension?

Symptoms of pulmonary hypertension are:

  • Shortness of breath.
  • Tiredness
  • Dizzy
  • Chest pain (angina)
  • Heart palpitations
  • Swelling in the legs, ankles, feet, or tummy (abdomen)

8. Is it necessary to fast before a VQ scan?

In general, no specific dietary preparation, such as fasting, is required before the scan. But you may be requested to get a chest X-ray 24 to 48 hours before your test.

9. What is the cost of a VQ scan?

The cost of a VQ scan in India is approximately Rs. 7000, however, it can vary due to place and hospital.

10. Where can I get a V/Q scan in Hyderabad?

To get a V/Q scan in Hyderabad, visit Medicover Hospitals, it offers the best range of diagnostic tests.