Diagnosis of Pulmonary Fibrosis
Arterial Blood Gas Test
Arterial blood carries oxygen from the lungs to the heart to be pumped around the body. The scar tissue that forms in the lungs of people with PF prevents oxygen from entering the blood. To assess the balance between oxygen and carbon dioxide in arterial blood in patients suspected of having pulmonary fibrosis, an arterial blood gas analysis is conducted.
A bronchoscopy is used to look inside of the airways. It involves inserting a small tube with a light at the end through a patient’s nose or mouth, down the throat into the trachea or windpipe, and down to the bronchi and bronchioles of the lungs. This procedure is used to identify the cause of lung problems. It may detect tumors, signs of infection, excess mucus in the airways, and bleeding or blockages in the lungs.
A chest X-ray, also called a chest radiography, is a rapid and painless imaging method that generates an image of the chest structures including the heart, lungs, ribs, and diaphragm. The image generated by the chest X-ray may present shadows, which indicate scar tissue. This allows the physician to diagnose the possibility of PF.
An electrocardiogram (ECG) is a simple, painless procedure that detects your heart’s electrical activity. An ECG can show how fast your heart is beating, whether the rhythm is steady or irregular, and the strength and regularity of the electrical impulses. An ECG may be recorded in a doctor’s office, an outpatient facility, in the hospital, or as part of stress testing.
Exercise testing consists of cardiovascular exercise on a treadmill or stationary bike that measures how well the lungs and heart respond to physical activity, and to evaluate oxygen levels in the blood. As the body works harder during the test, it requires more energy, so the heart needs to pump more blood.
A high-resolution computed tomography (HRCT) scan is an important tool to evaluate idiopathic PF. Several abnormalities can be observed using this method: ground-glass opacities, consolidation, reticulation, and honeycombing. The extent of fibrosis may also be measured by evaluating the combination of reticulation and honeycombing.
Pulse oximetry is a noninvasive procedure to monitor the amount of oxygen in a patient’s bloodstream. In patients with PF, the amount of oxygen that goes into the lungs while inhaling is less due to the increased difficulty in breathing. Therefore, less oxygen binds to hemoglobin, resulting in lower oxygen saturation levels.
A pulmonary function test known as spirometry measures the rate of air flow in and out of the lungs, and a person’s estimated lung size. Spirometry tests can be used to help diagnose a number of lung diseases, including asthma, chronic obstructive pulmonary disease, and other conditions that affect breathing. The test can also be used to see if a treatment is effective.
A surgical biopsy is both the most reliable way of diagnosing PF but also the most invasive. A tissue sample needs to be removed from the patient’s lung in order to be analyzed and determine if there is thickening of the pulmonary walls. A surgeon may choose a thoracotomy or a video-assisted thoracoscopic surgery. The decision about which surgery to perform depends on the physician’s evaluation of each patient.