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.

spiral computed tomography

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.

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.

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 With the exception of renal tomography most tomographic procedures have been replaced by computed tomography (CT).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.

CAUTION!

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.

CAUTION!

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

Zonography.
Enlarge picture
POSITRON EMISSION TOMOGRAPHY: PET SCAN revealing lung cancer
Enlarge picture
PET SCAN OF BRAIN

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

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.

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.
References in periodicals archive ?
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.
Contract award notice: Supply, Installation, Commissioning and maintenance of a 64-slice helical ct for gai ciudad real.
Investigators from Strasbourg reported on the use of Helical CT scanning to assess response to neoadjuvant chemotherapy.
Helical CT has been reported to isentify diaphragmatic injuries with a higher sensitivity and specificity compared to chest radiographys.
EKG gated dose modulated 128 slice helical CT images of the heart were obtained with optimal opacification of the left sided cardiac chambers and the aorta.
Methods: We performed a retrospective cohort study of patients with symptomatic urinary calculi diagnosed by unenhanced helical CT.
Improved detection of renal pathologic features on multiphasic helical CT compared with IVU in patients presenting with microscopic hematuria.
Reduced frequency of sedation of young children with multisection helical CT.
HeliExtend, a helical CT feature, can eliminate artifacts in long parts that have a small diameter.
Peripancreatic vascular abnormalities complicating acute pancreatitis: contrast-enhanced helical CT findings.