What is pulmonary ventilation and perfusion?

The ventilation scan is used to see how well air moves and blood flows through the lungs. The perfusion scan measures the blood supply through the lungs. A ventilation and perfusion scan is most often done to detect a pulmonary embolus (blood clot in the lungs).

What is the relationship between ventilation and perfusion?

Ventilation (V) refers to the flow of air into and out of the alveoli, while perfusion (Q) refers to the flow of blood to alveolar capillaries. Individual alveoli have variable degrees of ventilation and perfusion in different regions of the lungs.

What factors affect pulmonary perfusion?

Factors which affect regional pulmonary blood flow:

• Lung volume (atelectasis increases pulmonary vascular resistance)
• Hypoxic pulmonary vasoconstriction.
• Gravity (affects the direction of the hydrostatic gradient)
• Pulmonary vascular architecture (some lung units are structurally advantaged)

Which disease is the alveoli ventilated but not perfused?

pulmonary shunt
In pulmonary shunt, alveoli are perfused but not ventilated. Blood flowing past poorly ventilated alveoli doesn’t pick up additional oxygen. This poorly oxygenated blood returns to the heart and mixes with oxygenated blood coming from other areas of the lungs that are ventilated.

When is ventilation perfusion scan used?

A ventilation and perfusion scan is most often performed to detect a pulmonary embolus. It is also used to evaluate lung function in people with advanced pulmonary disease, such as COPD, and to detect abnormal circulation (shunts) in the pulmonary blood vessels.

What does perfusion of the lungs involve?

A perfusion scan looks at how blood is flowing within your lungs. In a perfusion scan, the radioactive tracer is absorbed evenly where blood flow is normal. Areas that are not getting blood do not absorb the tracer. In a ventilation scan, the tracer will fill the lungs unless you have an area where the air cannot move.

What is a lung perfusion test used for?

Why is a pulmonary ventilation and perfusion scan performed?

Why the Test is Performed. The ventilation scan is used to see how well air moves and blood flows through the lungs. The perfusion scan measures the blood supply through the lungs. A ventilation and perfusion scan is most often done to detect a pulmonary embolus (blood clot in the lungs).

Do you have to lie still during a Ventilation Scan?

The mask used during the ventilation scan may make you feel nervous about being in a small space (claustrophobia). You must lie still during the scan. The radioisotope injection usually does not cause discomfort. The ventilation scan is used to see how well air moves and blood flows through the lungs.

What is the purpose of V / Q lung scanning?

The objective of this study was to define the sensitivity, specificity and accuracy of ventilation-perfusion (V/Q) lung scanning in distinguishing chronic thromboembolic pulmonary hypertension (PHT) from other nonembolic causes of PHT.

How are lung scans used to diagnose PHT?

Methods: The V/Q lung scans from 75 patients in whom a confirmed cause of PHT was established were retrospectively reviewed. Twenty-five patients (33%) had chronic thromboembolic PHT, whereas 35 patients (47%) and 15 patients (20%) suffered from primary PHT and secondary nonthromboembolic PHT, respectively.