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Biomedical subjects

B C Wilson

Publications and source records attributed to B C Wilson.

At least 127 records · Page 7Linked to original sources
PubMed1982

Comparative evaluation of several rare-earth film-screen systems.

Comparisons of image quality were made for several rare-earth film-screen combinations under conditions similar to those used in chest radiography. The characteristic curve, modulation transfer function, and Wiener spectrum were measured. Observer response studies were carried out to compare the limits of perceived resolution. Signal-to-noise considerations based on the measured characteristics favor a fast film-show screen pair over a slow film-fast screen pair, consistent with the observer study results. The interrelationship of the physical parameters in determining image quality and the limitations of the method are discussed.

Humans↗
PubMed1981

Computer processing of perfusion, ventilation, and V/Q images to highlight pulmonary embolism.

A method is described for generating regional ventilation/perfusion (V/Q) images of the lung to aid assessment of suspected pulmonary embolism, especially in patients with obstructive airways disease. The radionuclide scans used for this are stored on a computer and comprise; lung perfusion (P) with Tc-99 m MAA, lung ventilation at equilibrium (E) with Xe-127, and the sum of the Xe-127 washout images (W). A functional ventilation image is calculated as V=E/W and a functional perfusion image as Q=P/E. Finally a ventilation perfusion ratio image is obtained by taking V/Q. This is normalised by a factor determined from the cumulative frequency distributions of the counts per pixel in the Q and V images so that areas which are well ventilated and perfused are given a V/Q value of 1.10. Areas with normalised V/Q values greater than 1.5 suggest pulmonary embolism. In 100 studies on patients with pulmonary embolism. In 100 studies on patients with abnormal perfusion scans this method proved very helpful by assisting the recognition or exclusion of areas with abnormally high V/Q values.

Adult↗
PubMed1981

Correlation of computed tomography and nephrography in quantitative comparison of urographic contrast agents.

The use of computed tomography (CT) to estimate the differences in radiographic contrast obtainable with different contrast agents is discussed. A CT scanner was calibrated to measure the in vivo iodine concentration, and phantom studies were performed to derive the relationship between iodine concentration and resultant radiographic contrast in the kidneys. The technique is illustrated by a quantitative comparison of the nephrographic phase in dogs with two urographic contrast agents, sodium iothalamate and sodium ioxaglate.

Animals↗
PubMed1980

Diagnostic and therapeutic impact of computerized tomography in patients with malignant brain tumours: South Australian experience.

The incidence of malignant brain tumours in the South Australian population has been determined for two six-months periods before and after the introduction of computerized tomography (CT). The impact of CT on diagnosis and short-term patient status has been analysed in patients with astrocytoma or glioblastoma multiforme. CT has significantly altered neuroradiological practice in these patients, but appears to have had little impact on prognosis or outcome.

Adolescent↗
PubMed1980

Changes in neurological practice in South Australia after the introduction of computerized tomography.

There has been no significant change in the age distribution of patients undergoing neuroradiological investigations after the introduction of computerized tomography (CT) in South Australia. The referral pattern has not changed, and adequate clinical neurological assessment was apparent both before and after the availability of CT, with the application of CT being selective rather than additive. Initial impression suggests some reduction in bed utilization after the introduction of CT.

Adolescent↗
PubMed1980

Kinetic studies of a quantitative single-tube enzyme-linked immunosorbent assay.

We describe a single-cuvette enzyme-linked immunosorbent assay (ELISA) based on enzymic rate kinetics. This kinetic assay can yield linear quantitative data on immunoglobin concentrations. Optimum assay conditions, component concentrations, reaction intervals, and pH are described. Assay linearity and sensitivity are demonstrated in systems involving immunoglobulin G and antibodies to it, and with pooled sera from monkeys infected with Schistosoma mansoni.

Animals↗
PubMed1979

Impact of computerized tomography on neuroradiological investigations in South Australia.

Although there has been a reduction in cerebral angiographic (33%), pneumoencephalographic (70%) and radionuclide brain scanning (28%) investigations since the introduction of computerized tomography in South Australia, there has been a significant increase (56%) in the total number of neuroradiological investigations performed. At the same time, the number of patients who underwent neuroradiological investigations has risen by 75%. This is equivalent to approximately one person in every 290 per year.

Australia↗
PubMed1975

Neuropsychologic function of children with severe hearing impairment.

A neuropsychologic and medical study was carried out on a selected sample of 34 hearing-impaired children aged seven to 10 years at the onset of the study. In 16 children the cause of the hearing loss was thought to be exogenous. Eight of these had evidence for organic brain dysfunction. Nine children were thought to have genetic etiologies, and in nine no cause could be determined (sporadic hearing loss). Medical examination revealed several unsuspected abnormalities, particularly visual ones. Motor and visual motor deficits were frequent among hearing-impaired children with brain damage. The Performance Scale of the Wechsler Intelligence Scale for Children, and Raven's Coloured Progressive Matrices, as well as the Paper Folding item of the Hiskey-Nebraska Test of Learning Aptitude appeared sensitive to the presence of brain damage. The mean score for the WISC Performance Scale fell within the average range for hearing children, supporting previous findings of cognitive competence of the deaf. In this sample, Hiskey-Nebraska scores tended to be lower than WISC scores. Reasons for this discrepancy were suggested and did not appear to be accounted for by brain damage. Deficits in items requiring visual memory, sequencing, and categorization were relatively prevalent but showed no etiologic predilection. They were thought to be related to the consequence of hearing loss rather than to brain damage. Difficulty with stereognosis highlighted the problem of deciding why a hearing-impaired child might fail a particular task. This difficulty suggested that failure might not indicate a deficit in the function the task was designed to measure, but rather, reliance on an inefficient strategy for success.

Audiometry↗
PubMed1975

Digital reconstruction of point sources imaged by a zone plate camera.

Zone plate cameras are used for high sensitivity imaging of X- and gamma-ray sources. The image thus obtained requires decoding and numerical techniques are devised for this purpose. The response function and the signal-to-noise ratio for a single point source have been evaluated for zone plates with varying numbers of zones. Autocorrelation is the best of the methods examined, and the results are in good aggreement with those obtained using Monte Carlo techniques. The autocorrelation method can give a gain of 50% in signal-to-noise for a single point source over the maximum obtainable with optical decoding. Criteria for the choice of number of zones are discussed.

Computers↗
PubMed1975

Digital processing of images from a zone plate camera.

A method for the digital decoding of data obtained with a gamma camera fitted with a zone plate aperture is described. Taking a line source as the object, computer simulations have been used to examine the effects of noise, solid angle variations, shape of detector and detector resolution and methods of dealing with these effects are considered. Using an Anger gamma camera and a zone plate aperture both a line source and a thyroid phantom containing 99Tcm have been well reconstructed. The behaviour of the system with regard to resolution, signal-to-noise ratio and tomographic capability is discussed.

Computers↗
PubMed1975

Gemistocytic astrocytes in gliomas. An autoradiographic study.

Tritiated thymidine (3-H-T) was administered intravenously to seven patients with cerebral gliomas. Autoradiographs of biopsy specimens excised within the next four hours and of autopsy specimens from three of these patients obtained three weeks to six months after the single pulse of 3-H-T revealed the following: (a) no gemistocytic astrocytes and only a few giant astrocytes were labeled in biopsy specimens, despite a high overall labeling index of 5-10% (percentage of cells labeled in the total cell population); and (b) scattered foci of labeled genistocytes occurred in autopsy specimens, despite a sharp drop in overall labeling index. In histologic sections of these same specimens, genistocytes and giant cells occurred as the major cell types in an irradiated tumor, in large clusters near foci of degeneration, and as isolated cells in anaplastic foci. These findings suggest that: 1) gemistocytes and giant astrocytes are similar in origin and growth potential regardless of minor variations in morphology; 2) these cells multiply slowly, if at all, and are closely related to regressive changes within the tumor; 3) these cells may reflect profound proliferative activity in adjacent neoplastic cells; and 4) the labeling index and malignant potential of the tumor as a whole depend upon the more rapidly dividing tumor elements. Thus, if genistocytes and giant cells indicate malignancy, they do so secondarily, and the biologically harmless gemistocyte may be the loser in an intense competition for the substrates needed in cell proliferation.

Adolescent↗