What is the purpose of a lung ventilation/perfusion ratio scan?

The purpose of a lung ventilation/perfusion ratio scan, commonly referred to as a V/Q scan, is to assess lung function and blood flow. This imaging test evaluates both the airflow (ventilation) and the blood flow (perfusion) in the lungs, allowing healthcare providers to determine how well air is reaching the lung's air sacs compared to how well blood is flowing through the lung's blood vessels.

An optimal ventilation/perfusion ratio is crucial for effective gas exchange and overall respiratory efficiency. A V/Q scan can help identify conditions such as pulmonary embolism, where blood flow is disrupted, or other respiratory problems that can affect oxygenation. By analyzing the distribution of ventilation and perfusion, clinicians can gain valuable insight into lung health and address issues accordingly.

Other options, while related to respiratory health, do not accurately reflect the specific purpose of a V/Q scan. Diagnosing lung infections focuses more on microbiological assessments or imaging like CT scans. Measuring oxygen levels in the blood is typically done through arterial blood gas analysis or pulse oximetry. Evaluating cardiac function is usually approached through tests like echocardiograms or cardiac stress tests. Thus, the correct purpose of a V/Q scan is to assess both ventilation and perfusion, providing