pulmonary disorders
Chest Imaging
Chest Computed Tomography (CT)
CT defines intrathoracic structures and abnormalities more clearly than does a Chest x-ray . Chest CT is normally done at full inspiration. Aeration of the lungs during imaging provides the best views of the lung parenchyma, airways, and vasculature, and of abnormal findings such as masses, infiltrates, or fibrosis. Images obtained with the patient in the prone position can help differentiate dependent Atelectasis (which changes with changes in body position) from lung disorders that cause ground-glass attenuation in the dependent posterior parts of the lungs, which persists despite changes in patient position (eg, fibrosis due to CT angiography uses a bolus of an IV radiopaque contrast agent to highlight the pulmonary arteries, which is useful in diagnosis of Pulmonary Embolism (PE) . Contrast agent load is comparable to that with conventional angiography, but the test is quicker and less invasive. CT angiography provides sufficient accuracy for the detection of pulmonary emboli, so it has largely replaced conventional pulmonary angiography and, except in patients unable to tolerate contrast agents, ventilation/perfusion (V/Q) scanning. 