What is V/Q scanning used to evaluate?

V/Q scanning, or ventilation-perfusion scanning, is specifically used to assess the distribution of air (ventilation) and the flow of blood (perfusion) in the lungs. This imaging technique is crucial in identifying any discrepancies between the amount of air reaching the alveoli and the blood flow in the lung's capillaries. Such discrepancies can indicate conditions like pulmonary embolism, where blood flow to parts of the lung is obstructed.

The evaluation of blood circulation and air distribution is essential for diagnosing various respiratory and cardiovascular diseases. This test helps clinicians understand how well the lungs receive air and how efficiently blood flows to the lungs, providing a comprehensive view of the lung's functional status.

In contrast, while gas exchange efficiency is related to ventilation and perfusion, it is not the direct focus of a V/Q scan. Muscle activity in respiration pertains more to the mechanics of breathing rather than the assessment V/Q scanning provides. Overall lung capacity is measured through various pulmonary function tests and would not be assessed through V/Q scanning, which focuses on assessing the specific relationship between air and blood flow.