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Biomedical subjects

E G Duncan

Publications and source records attributed to E G Duncan.

6 recordsLinked to original sources
PubMed1992

High-resolution magnetic resonance imaging of experimental spinal cord injury in the rat.

The ability of magnetic resonance imaging (MRI) to display the anatomic changes after spinal cord injury in the rat were examined in postmortem specimens. With the clip compression technique, acute spinal cord injuries of three grades of severity were produced in adult male rats. One hour after injury, during which time physiological parameters were measured and maintained within the normal range, the rats were killed by transcardiac perfusion of formalin. The vertebral column containing the cervical and upper thoracic segments was excised and, after further formalin fixation, 20 contiguous MRI scans centered on the injury site were obtained using a spin-echo imaging sequence. The volume of signal acquisition for each image was 15 x 15 x 1.0 mm thick. The spinal cords were then removed from the vertebral column, sectioned, and stained for histological examination. Ten-micrometer serial sections of each cord were examined microscopically. MRI scans and microscopic sections at comparable levels were examined to determine the quality of anatomical detail and spatial resolution of the MRI scans. MRI scans with resolution of about 75 microns per pixel edge were obtained. At the site of injury, there was disruption of the normally well demarcated gray-white interface and variable areas of low signal intensity. Because of the resolution achieved, it was possible to determine that these low signal intensity areas were post-traumatic hemorrhages. Indeed, hemorrhages with dimensions of the order of 100 microns were detected on the MRI scans. Furthermore, by examining the serial sections of the cord, the extent of the injury along the cord could be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

In vitro magnetic resonance microimaging of the spinal cord.

A 2.0-T small animal imager equipped with 3 G/cm imaging gradient coils was used to obtain images of en bloc segments of the vertebral column containing the rat spinal cord and of a cadaveric human spinal cord. These images demonstrate the applicability of MR micro-imaging techniques to the study of interesting problems in medicine and biology. Images of transverse sections of the spinal cord with in-plane resolution of better than 0.1 mm were obtained from slices 1 mm thick. The images of normal and injured rat spinal cord vividly show that spinal cord injury in the rat can be visualized using MRI techniques. The MR image of the cadaveric human spinal cord shows subanachroid gray and white matter structures. A comparison with a photomicrograph indicates that it is the superior contrast of the MR image that leads to increased conspicuity.

Animals↗
PubMed1990

Comparisons of the clinical and radiological features and surgical management of posterior fossa meningiomas and acoustic neuromas.

Next to acoustic neuromas, meningiomas are the most common benign tumour of the posterior fossa. This paper reviews the personal experience of one of the authors with the management of 26 posterior fossa meningiomas and 212 acoustic neuromas. The aim was to compare the clinical and radiological features of these two types of posterior fossa tumours to determine whether they can be differentiated preoperatively. The study also aimed at analysing the surgical treatment of posterior fossa meningiomas. The results showed that posterior fossa meningiomas can usually be differentiated from acoustic neuromas on the basis of clinical and radiological features. Preoperative differentiation aids surgical management, especially for selection of surgical approach. In most instances, posterior fossa meningiomas can be totally resected with minimal morbidity and mortality.

Adult↗
PubMed1987

Comparison of surgical and conservative management in 208 patients with acute spinal cord injury.

The role of surgery in the management of acute spinal cord or cauda equina injuries remains controversial. The present study analyzed ten admission features and three outcome variables in 208 patients treated in an Acute Spinal Cord Injury Unit, 116 (56%) of whom underwent at least one spinal operation. The surgical and non-surgical groups showed no significant differences in the following seven clinical features: age, sex, distance travelled to the Unit, time interval between trauma and admission, type of accident, severity of injuries to the spinal cord, and severity of associated injuries. However, the two groups showed significant differences in level and type of vertebral column injury, and in the frequency of pre-existing spinal abnormalities. These differences were due to management policies which selected certain injuries for surgical or non-surgical treatment. One-third of the operative procedures were performed primarily for neural decompression, one-third primarily for reduction of bony structures and one-third for fusion. However, 95% of the operative patients had a fusion at the initial operation. Operative treatment was associated with a lower overall mortality rate (6.1%) than non-operative (15.2%), despite a higher frequency of thrombo-embolic complications in the surgical group. Overall, there was no difference between operated and non-operated patients in length of stay or neurological recovery. Surgical management of patients with acute spinal cord injury appears safe in terms of mortality rate and neurological recovery, but it has not been proven to improve the latter.

Acute Disease↗