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Results for “computed tomography”

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PubMed1987

The appearances of multiple biliary hamartomas of the liver (von Meyenberg complexes) on computed tomography.

Computed tomography is well established in the management of patients with malignant disease, both as a staging procedure before initiation of treatment and in follow up. The presence of unsuspected metastases may affect the decision to perform surgery on the primary tumour and may alter the management of suspected recurrent tumour. Two cases are presented of patients with primary carcinoma whose computed tomography images showed multiple focal hepatic lesions suggestive of metastases. However multiple biliary hamartomas were found on histology, in one case by biopsy and in the other at post mortem. The differential diagnosis and significance of multiple liver defects on computed tomography is considered.

Aged↗

PubMedDate not supplied

Noninvasive visualisation of coronary atherosclerosis with multislice computed tomography.

Computed Tomography (Electron Beam Tomography: EBCT and multislice computed tomography: MSCT) have recently emerged as non-invasive diagnostic modalities that can quantify coronary calcium which is not only as indicator of coronary risk, but also permits assessment of the coronary lumen. The 16-slice MS-CT, the most recent CT-scanner has a very high resolution, which allows non-invasive assessment of coronary plaques. This has led to a stimulus for further research to assess the role of MSCT coronary plaque imaging in the identification of high-risk coronary plaques.

Age Distribution↗

PubMed1991

Evaluation of dacryocystorhinostomy failure with computed tomography and computed tomographic dacryocystography.

Five patients with dacryocystorhinostomy failures were examined with computed tomography or computed tomographic dacryocystography. In computed tomographic dacryocystography, radiopaque dye was instilled into the lacrimal sac before computed tomography to show its shape, location, and relation to surrounding structures. Problems with the bony ostium were detected in all five patients. Recurrent nasal polyposis, a retained metallic clip, and an unresected ethmoid air cell were also identified. Computed tomography and computed tomographic dacryocystography provided important information that facilitated reoperation after dacryocystorhinostomy failure.

Adolescent↗

PubMed1978

Evaluation of abdominal abscess with computed tomography.

Computed tomography (CT) is valuable in providing a specific diagnosis of abdominal abscess and in determining its site and extent. Computed tomography is also capable of excluding an abscess with a high degree of certainty. In 31 of 34 patients with proven abdominal abscess, CT suggested the correct diagnosis and accurately defined the extent of involvement. In nine patients, the CT findings were specific for abscess. The CT appearance of abscess is diverse, largely depending on its location. The most common appearance is a low density mass often with higher density at the periphery. The presence of gas distributed within the mass or an extraalimentary air--fluid level allows an extremely confident diagnosis of abscess. Differential diagnostic possibilities are reviewed with emphasis on interpretive problems.

Abscess↗

PubMed1994

Evaluation of the skull base by SPECT. A comparison with planar scintigraphy and computed tomography.

Computed tomography is currently the standard diagnostic tool for the evaluation of the skull base. The complex anatomy of this area is the primary reason why planar bone scintigraphy is often unsatisfactory; exact localization of abnormalities may be very difficult. These limitations may be overcome by SPECT. Seventeen patients with clinical features of basal skull involvement were assessed by CT, SPECT, and planar scintigraphy. Subsequent clinical diagnoses were malignancy in 15 patients, vasculitis in 1 patient, and osteomyelitis in 1 patient. Computed tomography with IV contrast was performed through the skull base at 5 mm intervals. Planar scintigraphy with Tc-99m MDP was followed by SPECT. Bony involvement compatible with the clinical findings was demonstrated by CT scans in 6 patients, by planar scintigraphy in 7 patients, and by SPECT in 9 patients. The abnormalities that were identified by CT were all identified by SPECT. This study suggests that, in imaging the skull base, SPECT is more sensitive and provides better anatomical localization than planar imaging and appears useful in patients with a negative CT study.

Contrast Media↗

PubMed1986

Moment arm lengths of trunk muscles to the lumbosacral joint obtained in vivo with computed tomography.

Computed tomography is valuable in obtaining in vivo length of muscular moment arms, which can be used in biomechanical models. Using computed tomography, the authors measured lengths of the muscular moment arms of the erector spinae, psoas, oblique abdominal, and rectus abdominis muscles to the bilateral motion axis (about which flexion/extension movements occur) and to the anteroposterior motion axis (about which lateral bending occurs), both axes running through the lumbosacral joint. The subjects were 21 patients. Examinations were performed on a General Electric CT/T 7800 scanner. The average erector spinae moment arm to the bilateral motion axis was 68 mm, which is greater than the moment arm used earlier. The results also revealed significant differences in moment arm length between men and women for several muscles. The authors conclude that for some muscles different moment arm lengths should be used for men and for women. The moment arms reported are proposed for use in biomechanical models for calculating lumbosacral joint load.

Aged↗

PubMed1987

Anatomy of the abductor muscles of the hip as studied by computed tomography.

Computed tomography provides a non-invasive method for studying anatomy in live subjects. The abductor muscles of the hip were studied by using computed tomography to describe their position, size, and orientation. The outlines of the muscles were clearly identifiable; patterns that are associated with trauma, arthritis, and so on, differed from normal. The patterns in eighteen normal hips in twelve adults were mapped in detail. The cross-sectional areas of the abductor muscles were measured and vectors representing the total pull of the abductor muscle in the frontal and sagittal planes were constructed for each hip. The variations in individual and composite muscular anatomy were recorded. The inclination of the axis of the abductor muscle ranged from 17 to 26 degrees (standard deviation, 2.9 degrees) in the frontal plane and from -2 to 14 degrees (standard deviation, 4.2 degrees) in the sagittal plane.

Adult↗

PubMed1982

[Diagnosis of presacral tumor recurrence following rectum extirpation using computer tomography].

Computed tomography enables the direct visualization of presacral recurrences of their expansion and relations to adjoining organs. The signs and symptoms were described and discussed. The value of computed tomography was demonstrated by 23 patients with recurrences after resection of carcinomas of the rectum. There are problems in differentiating small tumor recurrences to scar tissue. Most of our recurrences were extensive.

Female↗

PubMed1999

[Radiation exposure and computed tomography].

Computed Tomography (CT) is recognized as a relatively high-dose diagnostic procedure. There is some obscurity in the literature about the doses due to conventional CT, spiral CT and High Resolution Computed Tomography (HRCT) of the chest. Conventional chest CT results in a radiation dose approximately 100 times that of a standard chest film and 10 times that of a mammography; on the other hand, conventional chest CT is safe for the lens and the pelvis (ovaries, testes and uterus). Radiation dose associated with helical CT is potentially lower than the dose associated with conventional CT. HRCT, consisting of 1- to 2- mm thick-sections performed at 10 mm intervals, has an effective radiation dose lower than that of conventional CT, even with high-dose techniques (400 mAs). HRCT scans obtained at reduced milliamperage (40-80 mAs), the so-called "low-dose HRCT technique", may provide satisfactory visualization of lung parenchyma in the majority of cases and is recommended in patients in whom radiation dose is a major concern (pediatric population or young women in order to minimize breast irradiation). The awareness of radiation dose will become increasingly important for both referring physicians and radiologists when determining indications and deciding which types of imaging procedures and specific protocols should be used.

Female↗

PubMed2004

Reflexions about imaging technique and examination protocol 1. Computed tomography.

Computed tomography as imaging technique is established since decades, especially in examinations of the orbit. New technical development of multi-slice helical CT requires new attention, concerning radiation burden. Always asked is the use of contrast material in orbital examination. Indications and contraindications are discussed.

Clinical Protocols↗

PubMed1985

Enhancement of pulmonary vasculature in pulmonary consolidation as seen by computed tomography.

Computed tomography of the chest is often useful in evaluating lung consolidation and endobronchial obstruction. Our case demonstrates a consolidated lung associated with endobronchial obstruction and an interesting finding of enhanced pulmonary vasculature contrasted against surrounding pulmonary parenchyma of low density. We believe this represents the computed tomography appearance of drowned lung.

Aged↗

PubMed1999

Tomography versus computed tomography for assessing step off in intraarticular distal radial fractures.

Computed tomography scans have supplanted conventional tomography for many applications and often are considered the imaging study of choice for assessing intraarticular distal radial fractures. Concern about cost containment in healthcare delivery prompts the question of whether the two studies provide comparable information and at what cost. Common intraarticular distal radial fractures were created in 12 lightly embalmed cadaveric specimens. The fractures were fixed with radiolucent Kirschner wires. Articular step off was measured with a caliper. Plain radiographs, computed tomography scans, and trispiral tomograms were obtained of each specimen. Maximal step off was measured blindly by two musculoskeletal radiologists and four hand surgeons. The radiographic measurements were compared with the actual step off and expressed as a positive or negative deviation from the actual value. There was no statistically significant difference between computed tomography scans and tomograms in predicting step off. In addition, the difference between actual and radiographic measurements was insignificant in tomogram readings and different in one of the computed tomography measurements. In the authors' institution, a tomogram costs $200, and a computed tomography scan costs $562. Trispiral tomography is more accurate and cost effective than computed tomography, and thus when available should be considered the imaging modality of choice for assessing articular step off in distal radius fractures.

Analysis of Variance↗

PubMed2003

[The condition of the auditory tube in patients with chronic purulent otitis media as shown by computed tomography].

Computed tomography (CT) was made in 25 patients with otitis media purulenta chronica (OMPC). Of them 17 patients had meso- or mesoepitympanitis and 8 patients had the history of radical operations on the ear. At first, CT was made of the temporal bone without contrast medium, then with instillation of the contrast medium through the external acoustic meatus and tympanic cavity into the auditory tube. Native computer tomograms of the temporal bones of 43 persons without any middle ear pathology were used as control. Non-contrast computer tomograms showed air in the lumen of the bone part of the auditory tube of all the examinees. It was impossible to obtain the image of the cartilage part of the auditory tube. None of 25 OMPC patients showed the signs of peritubal pneumatisation while it was registered in 14 healthy controls. By CT data, 14 of 17 patients with perforative OMPC had passable auditory tube even in aggravated inflammatory process, 3 of them had unpassable one. All 8 patients after radical operation had unpassable auditory tube. Thus, the method of contrast computer tomography determines passability of the auditory tube in the direction from the tympanic cavity to the nasopharynx and specifies the level of obstruction that is important to know before hearing improving operations of tympanoplasty type. Evaluation of the drainage function of the auditory tube basing on the time of evacuation of the contrast medium from the tympanic cavity to the nasopharynx was declared useless.

Adolescent↗

PubMedDate not supplied

Estimation of vertebral rotation and the spinal and rib cage deformity in scoliosis by computer tomography.

Computer tomography (CT) presents a method of determining longitudinal axis vertebral rotation and vertebral, spinal, and rib case deformity. Different rotation angles, distances, and indexes are defined and discussed. Radiation risks were evaluated and considered exceedingly small when compared to the ordinary spinal anteroposterior radiograph. In a model study the mean difference between actual vertebral rotation and measured rotation was 0.3 degrees if the vertebrae were tilted up to 20 degrees in either the frontal or sagittal plane. This accuracy was lost if the vertebrae were tilted 20 degrees in both the frontal and the sagittal plane. Computer tomography can be used for evaluation of the vertebral rotation in the frontal plane.

Humans↗

PubMedDate not supplied

Otosclerosis: comparison of complex-motion tomography and computed tomography.

A prospective computed tomographic and complex-motion tomographic evaluation was performed in 18 suspected or proven cases of otosclerosis. Although there was good agreement between both methods, there was no greater diagnostic accuracy with computed tomography. However, computed tomography demonstrated the changes better than complex-motion tomography.

Evaluation Studies as Topic↗

PubMed1976

Subependymal and intraventricular hemorrhage in neonates. Early diagnosis by computed tomography.

Computed tomography was used to evaluate subependymal and intraventricular hemorrhage in 11 formalin-fixed brains obtained at autopsy from newborn infants from a population with a known high incidence of cerebral hemorrhage. After scanning, the brains were step-sectioned at levels corresponding to those of the scans. Subependymal and/or intraventricular hemorrhage was demonstrated in 6 of the 11 brains. There was a very close correlation between the scan images and the gross pathological findings in the affected brains. The authors conclude that computed tomography is an accurate method for the diagnosis of neonatal cerebral hemorrhage.

Evaluation Studies as Topic↗

PubMed2004

Diagnostic imaging for pancreatic cancer: computed tomography, magnetic resonance imaging, and positron emission tomography.

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are sophisticated modalities typically used in the second-line diagnosis following routine clinical practice. Among them, CT is regarded as the standard imaging in diagnosing pancreatic cancer at present in Japan due to its popularity and reasonable reliability in wide-ranging diagnostic ability. However, even with multidetector row CT (MDCT), the demonstration of pancreatic cancer less than 1 cm in size remains nearly impossible. CT staging is considered accurate in one-half to two-thirds of patients, but limitations in the imaging of peripancreatic microinvasion and nodal or hepatic micrometastases still have a tendency to underestimate tumor extension. With recent advancement in imaging techniques, MRI has proven to be equal or superior to other imaging modalities in diagnosing pancreatic cancer. Most of all, it is expected that MRCP will become as effective an instrument as ultra-sonography (US) in the screening of pancreatic cancer. Functional imaging with PET using the glucose analog FDG can be used in the diagnosis of pancreatic cancer, but systemic or local disturbance of glucose metabolism may result in an incorrect diagnosis. The usefulness of PET is now considered in assessing tumor viability, monitoring tumor response to treatment, and detecting distant metastases.

Carcinoma↗

PubMed2005

The evolution and state-of-the-art principles of multislice computed tomography.

Computed tomography has revolutionized diagnostic radiology with the introduction of spiral CT in the early 1990s, allowing for the first time the acquisition of volume data without the danger of misregistration or double registration of anatomical details. The next revolution occurred in 1998 when all major CT manufacturers introduced multislice CT (MSCT) systems, which typically offered simultaneous acquisition of four slices, providing considerable improvement towards the goal of isotropic three-dimensional imaging. The most recent generation of MSCT systems acquire 64 slices per rotation, enabling a whole body CTA with 1,500 mm scan range and an isotropic resolution of down to 0.4 mm in only 22- 25 s. The tube and the detector measurement system belong to the most important system components of a CT system, having a large influence on system performance. For example, new rotating envelope tube design principles allow for faster rotation times and for double z-sampling techniques in order to increase resolution. The applied dose is ultimately the limiting factor for the improvement of image quality and increase in isotropic resolution. In order to make best diagnostic use of the applied dose, sophisticated dynamic dose adaptation techniques to patient size and geometry have been developed.

Equipment Design↗