A lung scan is a medical imaging test that produces detailed pictures of the lungs and surrounding chest structures. This non-invasive procedure helps doctors visualize internal anatomy and identify potential health issues.
What a Lung Scan Involves
Lung scans utilize various technologies to create images of the lungs. A common initial step is a chest X-ray, which generates images of the chest, helpful for viewing bones and large structures.
Computed Tomography (CT) scans offer detailed, cross-sectional images of the lungs. This method uses X-rays from multiple angles, processed by a computer to create comprehensive views of soft tissues, organs, and blood vessels. A contrast dye may be administered to enhance visibility.
Magnetic Resonance Imaging (MRI) uses strong magnetic fields and radio waves to produce images, providing high contrast for soft tissues without using X-rays. While less common for initial lung imaging due to the high air content in lungs, specialized MRI techniques are emerging that can assess lung function.
Positron Emission Tomography (PET) scans involve injecting a radioactive tracer to detect metabolic activity within cells. Cancer cells, which have higher metabolic rates, absorb more tracer and appear as brighter spots. PET scans are frequently combined with CT scans (PET/CT) to provide both functional and anatomical information.
Ventilation-Perfusion (V/Q) scans assess both airflow (ventilation) and blood flow (perfusion) in the lungs using radioactive tracers. This two-part scan helps identify areas where air and blood flow are mismatched, often indicating conditions like blood clots.
Why a Lung Scan is Performed
Doctors order lung scans to diagnose and monitor respiratory and chest conditions. These scans can help identify illnesses such as pneumonia, bronchitis, and emphysema. They also detect lung cancer or track its progression.
Lung scans are instrumental in identifying blood clots in the lungs, known as pulmonary embolisms, by assessing blood flow. They are also used to evaluate injuries to the chest, such as rib fractures or collapsed lungs. For individuals with chronic lung diseases like chronic obstructive pulmonary disease (COPD) or cystic fibrosis, scans help assess the severity of the condition. A lung scan can also investigate unexplained symptoms like a persistent cough, shortness of breath, or chest pain.
Preparing for and Undergoing a Lung Scan
Preparation for a lung scan is straightforward, though instructions vary by scan type. Patients are usually advised to remove any metal objects, such as jewelry, eyeglasses, or clothing with metal components like zippers or underwire bras, as these can interfere with imaging. Inform the medical staff about any allergies, especially to contrast dyes, or if pregnant. For some scans, like PET scans, you may be asked to fast for a few hours beforehand, though this is not always required for all lung scans.
During the scan, you will typically lie flat on a table that slides into the scanning machine, which may be shaped like a large donut or a tunnel. The technologist will monitor you from an adjacent room but can communicate with you through an intercom. You must remain still and may be asked to hold your breath briefly for clear images. The procedure itself is generally painless and non-invasive, with most scans taking only a few minutes. If a contrast agent is used, you might experience a warm sensation.
Understanding Lung Scan Results
After a lung scan, the images are sent to a radiologist, a medical doctor specializing in interpreting medical images. The radiologist examines the pictures for any abnormalities. Following their analysis, the radiologist compiles a detailed report that is then sent to the referring doctor.
Your referring doctor will then discuss the results with you, explaining what was found and what it signifies for your health. Results may be categorized as negative, indicating no unusual findings; positive, meaning something out of the ordinary was observed; or indeterminate, suggesting something unusual but not immediately requiring follow-up. If the scan reveals any concerning findings, your doctor will outline the next steps, which may include further tests, additional monitoring, or the initiation of a treatment plan.