What would a v/q scan tell the doctor about air flow through the affected part of the lung?

Matching: A v/q scan (aka ventilation perfusion lung scan) is specifically used in situations where there is a concern for either inadequate airflow or blood flow to certain areas of lung(s). While images are acquired for both air & blood flow, interpretation is based on how well these 2 are matched in healthy & diseased parts of lung. Interpretation depends on underlying disease process. Talk to your doc.

COPD: A V (ventilation) / Q ( perfusion ) lung scan is designed to tell a doctor why a patient MAY have shortness of Breath or chest pain. Most of the time these tests are ordered to confirm or exclude whether the patient has a pulmonary embolism ( blood clot) in the lungs. However even negative V/Q scans can detect early to sever signs of emphysema /COPD. Which can also because of shortness of breath