Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Computers”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1990

[Single photon emission computed tomography of the brain in Sturge-Weber syndrome using N-isopropyl-p-[123I] iodoamphetamine--a comparative study with X-ray computed tomography].

Single photon emission computed tomography (SPECT) of the brain using N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) was performed in 11 children with port wine stain on the face or head, aged 1.0-14.2 years at investigation. Four cases without neurologic symptoms had no specific abnormality on SPECT and X-ray computed tomography (CT). In 4 cases of so-called Sturge-Weber syndrome with developmental quotients (DQ) or intelligence quotients (IQ) more than 80 and the neurologic symptoms consisting of seizures and hemiplegia, SPECT showed localized reduction of IMP accumulation, and CT exhibited calcification, atrophy and enhancement in 2 cases of 3 with contrast medium infusion in the same areas. In 3 cases with DQ of 50-60 and severer neurologic symptoms, SPECT showed diffuse reduction or defect of IMP accumulation in the ipsilateral hemisphere, and CT exhibited remarkable atrophy, calcifications and enhancement in 2 cases with contrast medium infusion in the same hemisphere. In one case with severe neurologic symptoms, SPECT performed at an early stage showed high IMP accumulation in the ipsilateral hemisphere.

Adolescent↗
PubMed1989

[Application of computer systems in perinatology. II. Organization of computer systems in intensive care of the fetus and newborn].

The main computer systems used in perinatal medicine are described, with particular reference to the systems of analysis of perinatal data, analysis of cardiotocogram, obstetric ultrasonogram, assessment of the heart function of the newborn, records of respiratory activity in newborns, and use of computers in parenteral alimentation of newborns.

Diagnosis, Computer-Assisted↗
PubMed1986

Computed tomography of the lumbar spine. Experience with an Expert System in computer aided diagnosis.

The authors report their experience in the formulation of an Expert System for computer aided diagnosis in the examination of the lumbar spine with computed tomography. A large number of steps are identified in the process of diagnostic evaluation of CT examinations; about 80 decisional rules are considered and arranged in five 'areas'. The Expert System under study is a first proposal, intended for use by radiologists with some basic training.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

1978 memorial award paper: a computer-aided technique for overlaying cerebral angiograms onto computed tomograms.

We have developed a method which uses a digital computer to combine angiographic images of the cerebral vasculature with a computed tomogram of the brain. The procedure is simple and could be implemented in any radiology department equipped with both a CT scanner and a bi-plane angiography suite. We have performed the entire process in prototype on phantoms and on a patient and have produced images that appear accurate and informative.

Brain↗
PubMed1993

Brain sonography, computed tomography, and single-photon emission computed tomography in term neonates with perinatal asphyxia.

The clinical diagnosis of hypoxic-ischemic brain injury in neonates can be supported by radiologic studies including cranial sonography, computed tomography (CT), single-photon emission computed tomography (SPECT), magnetic resonance imaging, and positron emission tomography. The role of cranial sonography, CT, and SPECT in term neonates with perinatal asphyxia is reviewed in this article.

Adolescent↗
PubMed2003

Quality assurance for computed-tomography simulators and the computed-tomography-simulation process: report of the AAPM Radiation Therapy Committee Task Group No. 66.

This document presents recommendations of the American Association of Physicists in Medicine (AAPM) for quality assurance of computed-tomography- (CT) simulators and CT-simulation process. This report was prepared by Task Group No. 66 of the AAPM Radiation Therapy Committee. It was approved by the Radiation Therapy Committee and by the AAPM Science Council.

Computer Simulation↗
PubMed1986

The validity of computed tomographic scan findings for the localization of cerebral functions. The relationship between computed tomography and hemiparesis.

We studied recovery from hemiparesis in 52 patients who participated in the Hennepin County (Minnesota) Recovery From Aphasia Study. Our intent was to determine the anatomic correlates of recovery from hemiparesis and then to contrast computed tomography (CT)-hemiparesis relationships with CT-aphasia relationships in this same population. Hemiparesis was assessed at one month after onset and again at six months after onset. Computed tomographic scans were obtained five months after onset and analyzed quantitatively for lesion location. The presence or absence of arm paresis was strongly predicted by CT scan findings in the supratentorial corticospinal pathway. However, three of 25 nonparetic patients had lesions in the corticospinal pathway, and one of 22 severely paretic patients lacked an appropriate lesion. This study demonstrated that a small but inherent lack of specificity and sensitivity existed in the predictive power of CT localization of lesions potentially affecting the motor system, suggesting that some caution is necessary in interpreting the lesion-deficit relationships in less well-localized functions, eg, language. Besides considering the lack of precision in localizing with CT, the existence of individual differences both in anatomy and localization of function must be taken into account.

Adult↗
PubMed1999

Effect of four computer keyboards in computer users with upper extremity musculoskeletal disorders.

Eighty computer users with musculoskeletal disorders participated in a 6-month, randomized, placebo-controlled trial evaluating the effects of four computer keyboards on clinical findings, pain severity, functional hand status, and comfort. The alternative geometry keyboards tested were: the Apple Adjustable Keyboard [kb1], Comfort Keyboard System [kb2], Microsoft Natural Keyboard [kb3], and placebo. Compared to placebo, kb3 and to a lesser extent kb1 groups demonstrated an improving trend in pain severity and hand function following 6 months of keyboard use. However, there was no corresponding consistent improvement in clinical findings in the alternative geometry keyboard groups compared to the placebo group. Overall, there was a significant correlation between improvement of pain severity and greater satisfaction with the keyboards. These results provide evidence that keyboard users may experience a reduction in hand pain after several months of use of some alternative geometry keyboards.

Adult↗
PubMed2002

Computational simulations of stress shielding and bone resorption around existing and computer-designed orthopaedic screws.

Failure of an orthopaedic fixation due to stress shielding and consequent screw loosening is a major concern among surgeons: the loosened screws could not only interfere with the healing process but also endanger adjacent anatomical structures. In this study, the effect of the screw's engineering design (dimensions, profile shape and material properties) on the load sharing with adjacent bone and consequent bone resorption was tested, using a set of two-dimensional computational (finite element) models. An algorithm simulating local bone adaptation to strain energy density (SED) mechanical stimuli was developed and used to evaluate the biomechanical performances of different commercial screws. Two new designs, a 'graded-stiffness' composite screw, with a reduced-stiffness titanium core and outer polymeric threads, and an active-compression hollow screw that generates compressive stresses on the surrounding bone, were also evaluated. A dimensionless set of stress transfer parameters (STPs) were utilised for ranking the performances of the different screws according to the expected screw-bone load sharing and its evolution with adaptation of the surrounding tissue. The results indicated that commercial wide (6 mm thread diameter) trapezoidal and rectangular screw profiles have superior biomechanical compatibility with bone (i.e. predicted to be stable after 2 years). The graded-stiffness and active-compression screws provided the best biomechanical performances: bone loading around them was predicted to decrease by no more than 15% after 3 years, compared with a decrease of 55-70% in bone loading around commercially available screws. Computer simulations of bone adaptation around orthopaedic screws are demonstrated to be effective means for objective and quantitative evaluation of the biomechanical aspects of implant-tissue compatibility.

Bone Resorption↗
PubMed2000

Intraoperative ultrasonography versus helical computed tomography and computed tomography with arterioportography in diagnosing colorectal liver metastases: lesion-by-lesion analysis.

Helical computed tomography with arterioportography (CTAP) and intraoperative sonography (IOUS) are both recognized to be extremely sensitive in the detection of liver metastases measuring <2 cm in diameter. As sensitivity and specificity values for both techniques differ significantly in the literature and in default of sufficient published data regarding this subject, a lesion-by-lesion analysis was considered necessary. Accuracy of IOUS was compared with helical computed tomography (CT) and portal-phase contrast enhancement (CTAP) in the preoperative detection of liver metastases from colorectal carcinoma projected as a prospective blinded study. Cost efficiency should be determined. Liver CTAP and IOUS were evaluated in 33 patients with colorectal carcinoma. Metastases were resected in 10 cases, and the remaining 23 patients were observed for follow-up with CT investigations every 3 months for a period of 1 year. CTAP and IOUS detected all 13 lesions measuring 5-10 mm (13/13). One metastasis measuring >10 mm was missed by IOUS. CTAP presented an ideal sensitivity of 100%, but specificity was as low as 68%. IOUS sensitivity was 98% and specificity was 95%. IOUS and CTAP are of comparable value regarding the detection of liver metastases <10 mm. Both techniques may be used if resections of synchronous or metachronous metastases are planned in order not to miss limiting small lesions and to prevent superfluous liver surgery. Helical CT scan with dynamic intravenous contrast enhancement is considered the most cost-effective preoperative staging method, although local staging may not be achieved because of insufficient intraabdominal survey.

Adult↗
PubMed1982

Computer program for storage and retrieval of the nucleic acid structures: storing and updating of transfer RNA sequences - drawing of the secondary structure for transfer RNA by computer.

The availability of a large number of tRNA sequences has created a need for computer programs to store the data. A program written in FORTRAN language allows one to store tRNA sequences and to retrieve information. The data are stored in such a way that it allows a direct comparison of various tRNA sequences. Moreover, the program draws the 'cloverleaf' structure of any stored tRNA sequence and also provides the characteristics of minor, modified nucleosides and major references. Additions and corrections to the program and stored data can be made easily and an individual does not need computer programming skills to use the program.

Base Sequence↗
PubMed1987

Computed tomography number correlations for metrizamide computed tomographic ventriculography.

The authors describe a method that permits the determination of the precise intraventricular iodine concentration after metrizamide computed tomographic ventriculography. There is an observed linear relationship between computed tomography number (Hounsfield units) and iodine concentration. This relationship may be used to provide the basis for a method of evaluating ventricular fluid dynamics. This, in turn, is useful for the determination of the indications for a shunting procedure and for the evaluation of shunt function in a patient with an existing shunt.

Cerebral Ventricles↗
PubMed1995

Computer-assisted simulation of conventional roentgenograms from three-dimensional computed tomography (CT) data--an aid in the identification of unknown corpses (FoXSIS).

A computer simulation program (Forensic X-ray Simulation and Identification System, FoXSIS) is presented. FoXSIS calculates conventional X-ray summation images using any scanning parameters from three-dimensional CT data records. All those parameters decisive for X-ray morphology are freely selectable for realistic simulations: focus-object distance, object-film distance, centering of the X-ray beam, the location of the object in the patch of rays, brightness and contrast, as well as parallel and central projection. In addition, distance and angle measurements, as well as enlargements of details are possible. The program may be expected to help in the identification of unknown corpses now, and even more in the future on account of the increased use of clinical computed tomographies.

Forensic Medicine↗
PubMed2006

Computer-assisted categorizing of head computed tomography reports for clinical decision rule research.

STUDY OBJECTIVE: To develop software that categorizes electronic head computed tomography (CT) reports into groups useful for clinical decision rule research. METHODS: Data were obtained from the Second National Emergency X-Radiography Utilization Study, a cohort of head injury patients having received head CT. CT reports were reviewed manually for presence or absence of clinically important subdural or epidural hematoma, defined as greater than 1.0 cm in width or causing mass effect. Manual categorization was done by 2 independent researchers blinded to each other's results. A third researcher adjudicated discrepancies. A random sample of 300 reports with radiologic abnormalities was selected for software development. After excluding reports categorized manually or by software as indeterminate (neither positive nor negative), we calculated sensitivity and specificity by using manual categorization as the standard. System efficiency was defined as the percentage of reports categorized as positive or negative, regardless of accuracy. Software was refined until analysis of the training data yielded sensitivity and specificity approximating 95% and efficiency exceeding 75%. To test the system, we calculated sensitivity, specificity, and efficiency, using the remaining 1,911 reports. RESULTS: Of the 1,911 reports, 160 had clinically important subdural or epidural hematoma. The software exhibited good agreement with manual categorization of all reports, including indeterminate ones (weighted kappa 0.62; 95% confidence interval [CI] 0.58 to 0.65). Sensitivity, specificity, and efficiency of the computerized system for identifying manual positives and negatives were 96% (95% CI 91% to 98%), 98% (95% CI 98% to 99%), and 79% (95% CI 77% to 80%), respectively. CONCLUSION: Categorizing head CT reports by computer for clinical decision rule research is feasible.

Humans↗
PubMed2004

A study of trabecular bones in ovariectomized goats with micro-computed tomography and peripheral quantitative computed tomography.

Osteoporotic fractures occur most frequently in trabeculae-rich skeletal sites. The purpose of this study was to use a high-resolution micro-computed tomography (micro-CT) to investigate the changes in trabecular bone microarchitecture and to use a peripheral quantitative computed tomography (pQCT) to study changes in volumetric bone mineral density (BMD) in a large animal model resulted from ovariectomy (OVX). Ten adult goats were used for this study. The first iliac crest biopsy was harvested before OVX and served as baseline; the second biopsy was collected 6 months later from the opposite side for both pQCT and micro-CT measurements. Results showed that after 6 months of OVX, the BMD of the iliac crest biopsies decreased significantly by 16.3% (P < 0.05). The bone volume density (BV/TV), trabecular number (Tb.N), and connectivity density (Conn.D) measured with micro-CT decrease significantly after OVX, with an average decrease of 8.34%, 8.51%, and 18.52% (P < 0.05 each), respectively. The trabecular plate separation (Tb.Sp) was 8.26% (P < 0.05) greater than baseline after OVX. Significant correlations were found between the reduction of BMD and the decreases of BV/TV and Tb.N (r = 0.839 and 0.719, respectively; P< 0.001 both), as well as the increase of Tb.Sp (r = -0.758, P< 0.001) and SMI (r = -0.697, P< 0.001). In conclusion, this was the first experimental study in goat model to show that OVX-induced bone loss in goats was attributed by deterioration of trabecular microarchitecture.

Animals↗
PubMed2005

The accuracy of endoscopic ultrasonography with fine-needle aspiration, integrated positron emission tomography with computed tomography, and computed tomography in restaging patients with esophageal cancer after neoadjuvant chemoradiotherapy.

BACKGROUND: Patients with esophageal cancer who receive neoadjuvant chemoradiotherapy are restaged with computed tomography (CT), endoscopic ultrasound with fine needle aspiration (EUS-FNA), and integrated positron emission computed tomography (FDG-PET/CT), and the results affect treatment. METHODS: This is a prospective trial on a consecutive series of patients who had initial chest, abdomen, and pelvis CT scan; EUS-FNA; and fluoro-2-deoxy- d -glucose (FDG)-integrated PET/CT; neoadjuvant chemoradiotherapy; repeat staging tests; pathologic staging; and, if appropriate, resection with lymphadenectomy. The primary objective was to assess the accuracy of these 3 tests in restaging patients after neoadjuvant therapy. RESULTS: There were 48 patients (41 men), and 41 underwent Ivor Lewis esophagogastrectomy with lymphadenectomy. The accuracy of each test for distinguishing pathologic T4 from T1 to T3 disease is 76%, 80%, and 80% for CT scan, EUS-FNA and FDG-PET/CT, respectively. The accuracy for nodal disease was 78%, 78%, and 93% for CT scan, EUS-FNA and FDG-PET/CT, respectively ( P = .04). FDG-PET/CT correctly identified M1b disease in 4 patients, falsely suggested it in 4 patients, and missed it in 2 patients, whereas for CT, it was 3, 3, and 3 patients. Fifteen (31%) patients were complete responders, and FDG-PET/CT accurately predicted complete response in 89% compared with 67% for EUS-FNA ( P = .045) and 71% for CT ( P = .05). CONCLUSIONS: FDG-PET/CT is more accurate than EUS-FNA and CT scan for predicting nodal status and complete responders after neoadjuvant therapy in patients with esophageal cancer. FDG-PET/CT and CT alone provide targets for biopsy, but results are often falsely positive.

Adenocarcinoma↗
PubMed2005

What imaging studies are necessary for abdominal aortic endograft sizing? A prospective blinded study using conventional computed tomography, aortography, and three-dimensional computed tomography.

OBJECTIVE: Preoperative imaging modalities for endovascular abdominal aortic aneurysm repair (EVAR) include conventional computed tomography (CT), aortography with a marking catheter, and three-dimensional computed tomography (3D CT). Although each technique has advantages, to date no study has compared in a prospective manner the reproducibility of measurements and impact on graft selection of all three modalities. The objective of this study was to determine the most useful imaging studies in planning EVAR. METHODS: Twenty patients being considered for EVAR were enrolled prospectively to undergo a conventional CT scan and aortography. The CT scans were then reconstructed into 3D images using Preview Treatment Planning Software (Medical Media Systems, West Lebanon, NH). Four measurements of diameter and six of length were made from each modality in determining the proper graft for EVAR. RESULTS: Measurements from all three modalities were reproducible with intraobserver correlation coefficients of 0.79 to 1.0 for aortography, 0.87 to 1.0 for CT, and 0.96 to 1.0 for 3D CT. Measurements between observers were also similar from each modality; interobserver correlations were 0.70 to 0.97 for aortography, 0.76 to 0.97 for CT, and 0.73 to 0.99 for 3D CT. Significant differences ( P < .01) in diameter measurements were noted at D2 with aortography compared with 3D CT, whereas differences in length measurements were found between CT and 3D CT at L4 (nonaneurysmal right iliac) ( P < .01). The correlation between CT and 3D CT for most length measurements was acceptable (0.63 to 1.0). Aortography for diameters correlated poorly (0.35 to 0.67) with 3D CT. When the endograft selected by aortography/CT or 3D CT alone was compared with the actual endograft used, there was agreement in 11 of 11 patients when adjusted for +/- one size in diameter or length. CONCLUSION: Reproducible and comparable measures of diameter and length can be obtained by each of three imaging modalities available for endograft sizing. As a single imaging modality, 3D CT appears to have the best correlation for both diameters and lengths; however, the difference is not sufficient enough to alter endograft selection. Three-dimensional CT may be reserved for challenging aortic anatomy where small differences in measurements would affect patient or graft selection for EVAR.

Aged↗
PubMed2001

Noninvasive coronary angiography by magnetic resonance imaging, electron-beam computed tomography, and multislice computed tomography.

In recent years, several techniques for noninvasive imaging of the coronary artery lumen (noninvasive coronary angiography) have been developed. These techniques include magnetic resonance imaging, electron-beam computed tomography, and, most recently, multislice computed tomography. Each of these techniques has specific advantages and disadvantages. Currently, EBCT seems to permit the most robust coronary artery imaging. In the future, imaging modalities will have to be further improved and validated in order to define specific areas for potential clinical applications.

Clinical Trials as Topic↗