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Biomedical subjects

E Dykes

Publications and source records attributed to E Dykes.

12 recordsLinked to original sources
PubMed1994

Cystic mesothelioma of the peritoneum: a rare cause of 'ascites' in children.

A 2-year-old girl presented with a 3-month history of progressive painless abdominal distension. Results of the clinical examination suggested massive ascites, but no other symptoms or signs could be elicited. There was no history of any other illness preceding the onset of distension. Ultrasonography and a computed tomography scan confirmed gross ascites, with multiple thin-walled loculi throughout the abdomen, from the diaphragm to the pelvis. The preoperative diagnosis was intraabdominal lymphangioma. During laparotomy, multiple transparent cysts were found throughout the peritoneum. There was no evidence of malignancy in any organ, and the cysts appeared almost completely avascular. Histological and ultrastructural appearances were those of benign cystic mesothelioma of the peritoneum, a condition that hitherto has been recognized only in adults. It is thought to represent a borderline variant between a truly benign adenomatoid lesion and the better-known malignant mesothelioma. The experience with adult cases suggests a high potential for recurrence but no progression to malignancy. It is possible that some cases of intraabdominal lymphangioma may have been misdiagnosed in the past; future cases should be fully evaluated, both immunohistochemically and ultrastructurally, to establish the true incidence of mesothelial proliferative disease in children.

Ascites↗
PubMed1994

Accuracy of prenatal diagnosis of congenital cystic adenomatoid malformation.

A series of 13 consecutive patients with a prenatal diagnosis of congenital cystic adenomatoid malformation (CCAM) were reviewed with respect to prenatal ultrasound findings, clinical features at birth, and postnatal outcome. In two cases (15%) the abnormality regressed in utero. Only three infants (23%) showed any respiratory distress at birth. After a mean of 25 months postnatal follow up, 11 patients (85%) were found to have a definite pulmonary abnormality. In seven patients (54%) the specific prenatal diagnosis of CCAM has been confirmed (five histologically, two radiologically). Four infants (31%) were found to have other types of pulmonary abnormality and in two (15%) the lungs remain apparently normal. Prenatal ultrasound appears reliable in the detection of pulmonary abnormalities but the variety of conditions identified postnatally suggests that specific prenatal diagnoses and prognoses should be avoided; prenatal counselling and perinatal management should be adapted accordingly.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed1993

Accurate measurement of surface areas of anatomical structures by computer-assisted triangulation of computed tomography images.

There is a need for accurate surface area measurement of internal irregular anatomical structures in order to define light dosimetry in adjunctive intraoperative photodynamic therapy (AIOPDT). No satisfactory preoperative method exists of measuring this parameter. We have investigated whether computer-assisted triangulation of serial sections generated by computed tomography (CT) scanning can give an accurate assessment of the surface area of the walls of the true pelvis after anterior resection and before colorectal anastomosis. We have shown that the technique of paper density tessellation is an acceptable method of measuring the surface areas of phantom objects, with a maximum error of 0.5%, and is used as the gold standard. Computer-assisted triangulation of CT images of standard geometric objects and accurately-constructed pelvic phantoms gives a surface area assessment with a maximum error of 2.5% compared with the gold standard. The CT images of 20 patients' pelves have been analysed by computer-assisted triangulation and this shows that the surface area of the walls varies from 143 cm2 to 392 cm2. Simple step-like analysis of images and approximation to geometric shapes with subsequent calculation give unacceptably high errors. The surface area of an internal, rigid, irregular surface area for illumination in AIOPDT can be accurately measured preoperatively by computer-assisted triangulation of CT images.

Anthropometry↗
PubMed1993

Three-dimensional reconstruction: methods of improving image registration and interpretation.

(i) Image registration. The use of serial images for computerised three-dimensional reconstruction necessitates the inclusion of three separate sources of information at the stage of data input. These are (i) artificial registration points or fiducials, (ii) a calibration scale and (iii) an outline of each slab of the section to be included in the reconstruction. Most traditional methods rely on the production of drawings of the contours of the structure under investigation which also include both registration points and a calibration scale. We report on a method which considerably reduces the time involved at this labour intensive stage of reconstruction and in addition allows subsequent reconstructions of different structures to be performed without new drawings. Use is made of computerised alignment of tissue sections and the production of composite photomicrographs of both the tissue under investigation and an accurately registered stage micrometer scale. (ii) Improving image interpretation. Images derived from computerised three-dimensional reconstruction can be affected by the number of coordinates used to form the contour of each slice of a structure and by the number of slices that are used to construct the final model. Too little or too much data can considerably reduce the ability of the observer to interpret accurately the image generated by the computer. We report on a feature-based method which enables the experimenter to assess objectively the amount of data required in the two-dimensional plane, i.e. the number of data points per slice, and the three-dimensional plane, i.e. number of slices per structure, so that optimal reconstructions are generated.

Computer Graphics↗
PubMed1990

Thoracic vascular injuries: a post mortem study.

We reviewed the coroner's records for all pediatric (less than 16 years of age) trauma fatalities in Ontario (population, 9.5 million) for the period January 1, 1985, through December 31, 1987. Twenty-six (8%) of the 322 cases for which complete autopsy data were available had major thoracic vascular injuries. Twenty-five deaths occurred within 6 hours of injury. The majority of patients had at least one AIS 6 injury. The aorta was the most frequently injured vessel. Major thoracic vascular injuries are more common among children than previous reports suggest, probably because they are rapidly fatal. Many deaths occur in the field, at local hospitals, or in transit before the patient can reach a trauma center. Efforts to reduce the number of total thoracic vascular injuries should focus on primary and secondary prevention.

Adolescent↗
PubMed1984

Computer-generated three-dimensional visualization of the trigeminal nuclear complex.

The spatial configuration of the trigeminal nuclear complex has been determined using new computer techniques aided by color graphic display facilities. Precise, statistical computer-generated drawings are provided of the three-dimensional anatomy of the nuclear complex and spinal tract of the fifth cranial nerve, as well as adjacent structures. Techniques for viewing these structures from variable directions and producing stereopairs are presented.

Computers↗
PubMed1983

Three-dimensional stereotactic anatomy of the human trigeminal nerve nuclear complex.

The trigeminal nuclear complex and its spinal tract extend throughout the greater part of the brain-stem and at medullary levels form the target site for producing stereotactic lesions. This paper describes a method for three-dimensional drawings of this nuclear complex. A stereotactic atlas of the human brain-stem and cerebellar nuclei has formed the data base. The two-dimensional composite transverse sections, at 1-mm intervals have been digitized using an X-Y coordinate plotting microscope. Computer programs have been written to generate drawings of a single transverse hemisection as well as regeneration of the opposite hemibrain-stem section. Specific programs were used to reconstruct serial transverse section outlines and incorporate the trigeminal nuclear complex with and without hidden line removal techniques and colour graphic display facilities. Rotation about the x, y and z axes was possible and permits any view of the reconstructed specimen to be computer-generated. A further program for reconstructing structures as stereopairs is presented.

Brain Mapping↗
PubMedDate not supplied

Applications of a microcomputer-based reconstruction system to produce realistic three-dimensional shaded images from serial sections.

A microcomputer-based system is described that generates three-dimensional shaded images from serial section data. It is implemented on the IBM PC-AT microcomputer, using a graphics display card (Real World Graphics PC 4000) to provide sufficient colours for the production of realistically shaded and highlighted images. Image generation time is typically less than 10 min. The capabilities of the system are illustrated by reconstructions of the Kurloff cell from the guinea-pig (based on serial electron micrographs), human teeth (based on light microscope data), the human leg (from gross anatomical sections) and the human brainstem (from stereotaxic atlas data). The system is applicable to a wide variety of serial section data from histological, anatomical and medical imaging systems and ultrastructural studies.

Animals↗