What does a VQ scan primarily assess in the body?

A VQ scan, or ventilation-perfusion scan, primarily assesses pulmonary blood flow and ventilation within the lungs. This diagnostic imaging technique is used to evaluate the distribution of air (ventilation) and blood (perfusion) in the pulmonary system. By comparing these two factors, the scan helps identify any areas of the lungs that may not be receiving adequate blood flow or airflow, which is crucial in diagnosing conditions such as pulmonary embolism.

When interpreting the results of a VQ scan, clinicians look for mismatches between ventilation and perfusion. For example, if a region of the lung is well-ventilated but poorly perfused, it may indicate a blockage in the pulmonary blood vessels. Thus, the primary focus of a VQ scan revolves around assessing the efficiency and functionality of the lungs in terms of both airflow and blood circulation, making it an essential tool for evaluating respiratory conditions.

In contrast, the other options pertain to entirely different organ systems and functions, highlighting their irrelevance to the specific functions of a VQ scan.