Perfusion scans (MAA) for lung shunts and lung quantification Home A-Z Health Information Health Library A-Z Perfusion Scans (MAA) For Lung Shunts and Lung Quantifica... Overview A Lung Perfusion scan is a diagnostic test used to evaluate blood flow (perfusion) to the lungs in specific situations and may be used to:Assess lung function before lung surgeryMonitor lung function after treatment or surgeryEvaluate lung diseases such as chronic obstructive pulmonary disease (COPD) or emphysemaQuantify liver-lung shunts How Should I Prepare for the Scan? Medications: Inform your doctor about all medications you are taking, including blood thinners or inhalers. You may be asked to stop certain medications before the scan.Allergies: Notify your doctor if you have any allergies, especially to iodine, contrast agents, or medications.Pregnancy and breastfeeding: If you are pregnant or breastfeeding, inform your doctor. What Happens During the Procedure? You will receive a small amount of radiopharmaceutical injection into a vein in your arm to evaluate blood flow through your lungs.The gamma camera will take more images of your lungs, and in some cases, images of your brain and abdomen will also be taken.This part takes about 15-30 minutes. What to Expect During the Test? You will lie down on a table while the gamma camera takes pictures. The camera will move around your chest but will not touch you.The procedure is generally painless, though you may feel a slight pinch from the injection.The entire process usually takes 30-60 minutes. After the Procedure You can resume normal activities immediately after the scan.Drink plenty of fluids to help flush the radioactive tracer from your body.The radioactive material will naturally leave your body within 24 hours.