What medical emergency can be screened by a V/Q scan?

A V/Q (Ventilation/Perfusion) scan is a diagnostic imaging test used primarily to evaluate pulmonary function, particularly in the context of certain pulmonary vascular conditions. The correct answer, which identifies a pulmonary embolus as a medical emergency that can be screened by a V/Q scan, highlights the test's primary purpose.

In the case of a pulmonary embolus, the scan assesses the airflow (ventilation) and blood flow (perfusion) in the lungs. A V/Q scan can show areas of the lung where ventilation is normal but perfusion is reduced or absent, indicating a blockage in blood flow due to an embolus. This makes it an effective tool for diagnosing pulmonary embolism, which can be life-threatening if not identified and treated promptly.

In contrast, conditions like pneumothorax, chronic obstructive pulmonary disease (COPD), and acute respiratory distress syndrome (ARDS) are not effectively screened by a V/Q scan. Pneumothorax is typically assessed through chest X-rays or CT scans, COPD is evaluated through pulmonary function tests and imaging for lung structure rather than ventilation-perfusion mismatch, and ARDS is generally diagnosed clinically and confirmed through imaging for the presence of bilateral infiltrates, which is not identifiable via a V