spiral computed tomography

(redirected from helical CT)

spi·ral com·put·ed to·mog·ra·phy

computed tomography in which the x-ray tube continuously revolves around the patient, who is simultaneously moved longitudinally; computer interpolation allows reconstruction of standard transverse scans or images in any preferred plane.
Farlex Partner Medical Dictionary © Farlex 2012

spiral computed tomography

Helical scanning Imaging CT imaging based on 'slip-ring' technology, in which a large image volume is acquired by continuous rotation of the detector. See Computed tomography, Cf High-resolution computed tomography.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

spi·ral com·put·ed tom·og·ra·phy

(spīrăl kŏm-pyūtĕd tŏ-mogră-fē)
Computed tomography in which the x-ray tube continuously revolves around the patient, who is simultaneously moved longitudinally.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


(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 With the exception of renal tomography most tomographic procedures have been replaced by computed tomography (CT).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.
Medical Dictionary, © 2009 Farlex and Partners

spiral computed tomography

A development of CT scanning that is rapid, allows scanning of a large body volume on a single breath-hold, and provides high-quality two- and three-dimensional images. The X-ray tube rotates around the patient in a spiral, taking less than a second to complete one rotatation. Up top 60 rotations are possible. A special surface-shading display reveals astonishing detail, especially of bones.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Small-bowel diseases: prospective evaluation of multi-detector row helical CT enteroclysis in 107 consecutive patients.
Usefulness of helical CT angiography and MRI in the diagnosis and treatment of Pentalogy of Cantrell.
Helical CT of diaphragmatic rupture caused by blunt trauma.
Reformatted 3-D CTU from thin-cut axial helical CT scans can create a coronal image similar to that of IVU.
In addition to improving safety, OmniTom delivers high quality non-contrast axial and helical CT, CT angiography, and CT perfusion scans at the point-of-care.
[5,6] Our study was done to determine the sensitivity of the renal resistive index in diagnosing obstructive uropathy taking non-enhanced helical CT as the gold standard.
Newer reconstruction algorithms for electronics, such as helical CT, can remove these flaws.
Mimics of renal colic: Alternative diagnoses at unenhanced helical CT. Radiographics 2004; 24: 11-28.
von Ballmoos, the imaging equipment for the facility includes Toshiba Lightning Aquilian Detector, Row Ultra Helical CT Scan, Hitachi Aperto Lucent Prime Open MRI, Canon / DelftDI Triathlon DR X - Ray Machine and Planned Clarity 2D Digital Mammography (Mammogram), among others.