Principles of computed tomography of the chest
- Paul Stark, MD
Paul Stark, MD
- Professor of Radiology
- University of California San Diego
- Section Editor
- Nestor L Muller, MD, PhD
Nestor L Muller, MD, PhD
- Section Editor — Pulmonary Imaging
- Professor of Radiology
- University of British Columbia
- Deputy Editors
- Geraldine Finlay, MD
Geraldine Finlay, MD
- Senior Deputy Editor — UpToDate
- Deputy Editor — Pulmonary, Critical Care, and Sleep Medicine
- Associate Professor
- Tufts University School of Medicine
- Susanna I Lee, MD, PhD
Susanna I Lee, MD, PhD
- Deputy Editor — Radiology
- Associate Professor of Radiology
- Harvard Medical School
- Massachusetts General Hospital
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 :
●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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- GENERAL DESCRIPTION
- Duration of the helix
- Reconstruction interval
- Gantry rotation time
- BREATHING INSTRUCTIONS
- INTRAVENOUS CONTRAST
- DATA PROCESSING
- TWO-DIMENSIONAL AND THREE-DIMENSIONAL RENDERING
- CT ANGIOGRAPHY
- MULTISLICE HELICAL CT
- Technical parameters
- ELECTRON BEAM CT
- RADIATION DOSE
- SUMMARY AND RECOMMENDATIONS