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Principles of computed tomography of the chest

Paul Stark, MD
Section Editor
Nestor L Muller, MD, PhD
Deputy Editors
Geraldine Finlay, MD
Susanna I Lee, MD, PhD


Computed tomography (CT) is an imaging technique that has revolutionized medical imaging. It is widely available, fast, and provides a detailed view of the internal organs and structures [1-3].    

The two major types of CT are helical CT and conventional, axial, step-and-shoot CT. Helical CT is most prevalent, but conventional step-and-shoot, axial technique is used for high-resolution CT scanning of the lungs, coronary artery calcium scoring, and prospective ECG-triggered coronary CT angiography.

The technical aspects of CT are reviewed here. The role of CT in various clinical situations is described separately. (See "High resolution computed tomography of the lungs" and "Computed tomographic and positron emission tomographic scanning of pulmonary nodules" and "Imaging of lung cancer" and "Computed tomography of the hepatobiliary tract" and "Noninvasive coronary imaging with cardiac computed tomography and cardiovascular magnetic resonance".)


The principal components of a CT scanner are the x-ray tube and a diametrically opposed array of detectors [4]:

The x-ray tube rotates around the patient and generates an x-ray beam (figure 1). The gantry motion is helical during helical CT and circular during conventional, axial, step-and-shoot CT.


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Literature review current through: May 2017. | This topic last updated: May 11, 2017.
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