computed axial tomography

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Related to computed axial tomography: CAT scan, magnetic resonance imaging, visceral muscle

computed axial tomography

Computerized axial tomography.

computed tomography

A diagnostic imaging technique in which multiple X-rays are taken from different angles in a single plane and a series of two-dimensional images (”slices”) of the different tissue densities—e.g., fat, muscle, bone, etc.—is constructed by computer. In contrast to conventional radiology, CT results in a 1000-fold increase in image resolution, and can pinpoint lesions < 2 mm in greatest dimension; dyes may be injected IV to increased resolution of abnormal tissue and blood vessels, or radiocontrast can be used for dynamic testing.

com·put·ed ax·i·al to·mog·ra·phy

(CAT) (kŏm-pyū'tĕd ak'sē-ăl tŏ-mog'ră-fē)
Synonym(s): computed tomography.


(to-mog'ra-fe) [ tomo- + -graphy]
A radiographic technique that selects a level in the body and blurs out structures above and below that plane, leaving a clear image of the selected anatomy. This is accomplished by moving the x-ray tube in the opposite direction from the imaging device around a stationary fulcrum defining the plane of interest. Tube movements can be linear, curvilinear, circular, elliptical, figure eight, hypocycloidal, or trispiral. With the exception of renal tomography most tomographic procedures have been replaced by computed tomography (CT). Synonym: body section radiography; body section roentgenography

computed axial tomography

Abbreviation: CAT
See: computed tomography

computed tomography

Abbreviation: CT
A computerized x-ray scanning system that produces a sectional anatomic image. It is achieved by digital processing of x-ray attenuation coefficients from a 360° wedge scan of ionizing radiation. There is considerable use of data from the attenuation coefficients in diagnosis. Computed tomography is colloquially called a cat scan.


CT scans expose patients to radiation on the order of 10 mSv per scan. Educational materials about the potential risks and benefits of scanning should be provided to patients to ensure that scans are performed safely and carefully.

computerized axial tomography

Abbreviation: CAT
See: computed tomography

electrical impedance tomography

Cross-sectional body imaging that reconstructs pictures of internal organs based on measurements of their electrical activity as detected by electrodes placed on the surface of the body.

electron-beam tomography

Ultrafast computed tomography

full body computed tomography

Abbreviation: FBCT
An examination from head to toe of the body with computed tomographic imaging, promoted as a screening test for cancer and other illnesses.


The test exposes patients to high levels of radiation, reveals more false positive findings than true positives, and is expensive.

Heidelberg retinal tomography

Abbreviation: HRT
A confocal laser scanning system that produces three-dimensional images of the posterior segment of the eye. It is used to diagnose and treat glaucoma.

helical computed tomography

Computed tomographic (CT) images that are obtained as the CT table moves continuously during a single, held breath. Detailed evaluation of dynamic internal features is feasible with this technique.
Synonym: spiral computed tomography

optical coherence tomography

Abbreviation: OCT
A radiographical method used to obtain high-resolution cross-sectional images of tissues and their defects, e.g., of the structures of the eye.

panoramic tomography

Enlarge picture
Enlarge picture

positron emission tomography

Abbreviation: PET
Reconstruction of brain sections by using positron-emitting radionuclides. By using several different radionuclides, researchers can measure regional cerebral blood flow, blood volume, oxygen uptake, and glucose transport and metabolism, and can locate neurotransmitter receptors. PET has been used with fludeoxyglucose F 18 to identify and localize regional lymph node metastases and to help assess response to therapy.

The images produced by PET are in colors that indicate the degree of metabolism or blood flow. The highest rates appear red, those lower appear yellow, then green, and the lowest rates appear blue. The images in various disease states may then be compared to those of normal subjects. Three- and four-dimensional reconstructions are often achieved through the use of computed tomography (CT) with the same machine. See: illustration


quantitative computed tomography

Abbreviation: QCT
A method for determining the bone mineral density of a three-dimensional bony specimen, e.g., in the vertebral bodies or the forearms. It is used in the diagnosis of osteopenia and osteoporosis.

single photon emission computed tomography

Abbreviation: SPET, SPECT
A medical imaging method for reconstructing sectional images of radiotracer distributions.
See: nuclear medicine scanning test; positron emission tomography

spiral computed tomography

Helical computed tomography.

ultrafast computed tomography

Computed tomographic scanning that produces images by rotating the x-ray beam at targets placed around a patient, instead of moving a patient on a gantry through the scanner. The technique minimizes patient movement artifacts and decreases scanning times to about 50 to 100 msec. It is capable of providing good resolution of vascular structures, such as the aorta and the coronary arteries. Synonym: electron-beam tomography

xenon-enhanced computed tomography

Computed tomographic scanning that uses the inert gas xenon to improve the visual distinction between healthy and abnormal tissues, esp. to visualize blood flow to different regions of the brain in stroke.

Computed axial tomography; CT or CAT scan

Computed axial tomography (CT) is a x-ray technique that has the ability to image soft tissue, bone, and blood vessels.
Mentioned in: Adhesions, Brain Biopsy

computed axial tomography (km·pyu·tid ak·sē·l t·mˑ·gr·fē),

Patient discussion about computed axial tomography

Q. I get bad headaches had ct scans and m.r.i. even sinus surgery, suffering 2yrs now, dizzness occurs too..

A. If all prior medical investigations turned out normal, and sinus surgery didn't help relieve your symptoms, I would suggest the reason for your headaches is probably migraine attacks, that can cause severe headaches, and no CT scan or MRI can diagnose them. The diagnosis is made clinically, by your doctor. Migraine headaches can be eased by proper medications, before and during an attack. You should consult a neurologist.

More discussions about computed axial tomography
References in periodicals archive ?
Key Words: computed axial tomography, retroperitoneal abscess
Using an SGI(R) Reality Center(TM) facility to convert computed axial tomography (CAT) scan data into a remarkably lifelike 3D image, researchers have been able for the first time to determine what lies hidden beneath the casing, or cartonnage, of a 3,000-year-old mummy, Nesperennub, housed at the museum since 1899.
Further advancements have come from magnetic resonance technology (MRI) and computed axial tomography (CAT).
MAGNET") to be the exclusive provider of mobile and fixed-site magnetic resonance imaging (MRI) and computed axial tomography (CT) services to member hospitals of MAGNET.
Virtual endoscopy is a technique that uses software to generate images of the inside of hollow organs, such as the colon and vascular structures, from computed axial tomography (CAT) scan data.
Diagnostic imaging procedures are used to diagnose various diseases and physical injuries through the use of magnetic resonance imaging, computed axial tomography, mammography, X-ray, ultrasound and other technologies.
Both MediTek and USDL are leading providers of medical diagnostic imaging services through their outpatient facilities which offer Magnetic Resonance Imaging (MRI), Computed Axial Tomography (CAT), Nuclear Medicine, Ultrasound, Mammography and X-Ray services.

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