<unk> , also called a<unk> , is a medical test to measure the circulation of air and blood within a patient's lungs. The<unk>  part of the test evaluates the ability of air to reach all parts of the lungs, while the<unk>  part measures how well the blood circulates within the lungs. This test is most commonly done in order to check for the presence of a blood clot or abnormal blood flow inside the lungs (pulmonary embolism or PE), although computed tomography with radiocontrast is now more commonly used for this purpose. A<unk>  may also be performed in the case of serious lung disorders such as COPD or pneumonia as well as a lung performance quantification tool pre and post lung lobectomy surgery.
Ventilation/perfusion scan
D-dimer
Computed tomography angiography
CT angiography
Angiogram
Magnetic resonance angiography
Peak flow meter
In vivo magnetic resonance spectroscopy