Question

What is the purpose of a ventilation-perfusion (V-Q) scan?

1) To assess lung function
2) To diagnose pulmonary embolism
3) To evaluate blood flow to the lungs
4) To measure oxygen levels in the blood

Answer 1

The purpose of a ventilation-perfusion (V-Q) scan is to diagnose conditions such as pulmonary embolism by revealing areas of V/Q mismatch in the lungs, which indicate imbalances between ventilation and blood perfusion.

Step-by-step explanation:

The purpose of a ventilation-perfusion (V-Q) scan is to assess the balance and interplay between the air that reaches the alveoli in the lungs (ventilation) and the blood that flows through the lungs' capillaries (perfusion). This medical imaging technique is particularly useful for diagnosing conditions such as a pulmonary embolism, where a blockage in one of the pulmonary arteries in the lungs may impair blood flow and, consequently, gas exchange. The scan can identify areas where there is a V/Q mismatch, which means there is a discrepancy between the areas of the lung receiving air and those supplied with blood, a critical consideration for correct diagnosis and treatment planning. It does not directly measure oxygen levels in the blood; this is typically done with a device called a pulse oximeter.