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Biomedical subjects

D Kidd

Publications and source records attributed to D Kidd.

49 records · Page 3Linked to original sources
PubMed1994

Correlation of magnetization transfer ratio with clinical disability in multiple sclerosis.

We performed spin echo magnetic resonance imaging with and without application of an off-resonance saturation pulse in 43 patients with multiple sclerosis (MS), 10 age-matched controls, and 4 elderly asymptomatic patients with the radiological diagnosis of small-vessel disease. Magnetization transfer (MT) ratio images were obtained from these. All MS subgroups (primary progressive, secondary progressive, benign, early relapsing-remitting) showed significantly lower average lesion MT ratios than small-vessel disease patients. Secondary progressive MS patients showed significantly lower lesion MT ratios than those with benign disease, and there was an inverse correlation of disability with average lesion MT ratio. The degree of reduction of MT ratios is an indicator of the extent of tissue destruction. Thus, reduced MT ratios in MS may provide an indication of the degree of demyelination and axonal loss, both of which are likely to cause functional deficits in MS. We conclude that MT measurement is (1) a robust quantitative method that may increase the pathological specificity of magnetic resonance imaging, (2) has the potential to differentiate demyelination in MS from less destructive pathological changes, and (3) may be useful in monitoring modifications in tissue structure brought about by treatment.

Adult↗
PubMed1994

Increased expression of high affinity IL-2 receptors and beta-adrenoceptors on peripheral blood mononuclear cells is associated with clinical and MRI activity in multiple sclerosis.

Enhanced expression of beta-adrenoceptor densities on peripheral blood mononuclear cells (PBMCs) in progressive multiple sclerosis patients has been observed in a number of independent studies. A link between increased number of beta-adrenoceptors and inflammatory disease has been further indicated by studies in rheumatoid arthritis and relapsing-remitting multiple sclerosis patients. In a serial monthly assessment of relapsing-remitting multiple sclerosis patients, we have demonstrated that increased beta-adrenoceptors on PBMCs correlate with the expression of high affinity interleukin-2 receptors (IL-2Rs) and disease activity as determined by clinical and MRI findings. Magnetic resonance imaging activity was strongly correlated with IL-2R expression and it appears to be a sensitive marker of PBMC immunoactivation in multiple sclerosis. In vitro studies showed that beta-agonist stimulation of PBMCs reduces the IL-2R expression and suppresses cell proliferation following mitogenic stimulation. This observation may indicate a recovery role for the enhanced beta-adrenoceptor expression in multiple sclerosis. However, its therapeutic importance remains to be tested by appropriate trials using either beta-agonists or agents activating the second messenger system, c-AMP, in lymphocytes.

Adult↗
PubMed1994

A comparison of the pathology of primary and secondary progressive multiple sclerosis.

The dynamics of primary progressive multiple sclerosis differ from those of the more common secondary progressive form. The observation by MRI that the frequency of enhancement with gadolinium-DTPA, a marker for blood-brain barrier dysfunction, is significantly less in the primary progressive form, has led to the hypothesis that inflammation is less intense in this group. To test this, we have studied postmortem material from nine cases judged from a retrospective analysis of case notes to show clear clinical evidence of either primary progressive or secondary progressive disease. Five hundred and seventy-eight lesions were analysed. There was significantly more inflammation in secondary progressive multiple sclerosis (as judged by the frequency of perivascular cuffing and cellularity of the parenchyma) than in primary progressive disease. These observations have implications for therapeutic strategies in progressive multiple sclerosis.

Adult↗
PubMed1994

Benign form of multiple sclerosis: MRI evidence for less frequent and less inflammatory disease activity.

Data from two serial studies comparing the MRI activity of two groups of 11 patients, one with early relapsing-remitting (mean disease duration 3.5 years), the other benign (mean disease duration 22 years) multiple sclerosis are presented. Those with benign disease developed fewer new or enlarging lesions, and such lesions that occurred had a lower incidence of gadolinium enhancement, a marker of inflammation. These results, when considered in conjunction with other published studies, suggest that both the frequency of new lesions and the amount of inflammation within them influence the development of disability in multiple sclerosis.

Adult↗
PubMed1993

Spinal cord MRI using multi-array coils and fast spin echo. I. Technical aspects and findings in healthy adults.

It is time-consuming to detect intrinsic spinal cord lesions in multiple sclerosis (MS) by MRI using conventional surface coils and T2-weighted spin-echo pulse sequences. Multi-array coils and fast spin-echo pulse sequences permit the generation of high-resolution T2-weighted sagittal images of the whole spinal cord in about 5 minutes. Using these advances, we found an area of high signal within the cord in only 1/45 (2%) healthy subjects aged 18 to 72 years, whereas 26% of those who underwent brain imaging had cerebral white matter abnormalities. Degenerative vertebral column changes, especially in the cervical region, were present in 64% and were associated with cord compression in 11%. Cord cross-sectional areas in mm2, measured from axial gradient-echo images, were usually highly reproducible and showed a significant correlation with the subject's height. We conclude that (1) MRI signal abnormalities within the spinal cord may be more specific for MS than cerebral white matter lesions, especially in subjects over 50 years old; (2) asymptomatic degenerative changes in the vertebral column are common, even in younger adults; (3) measurement of cord cross-sectional area should allow accurate quantitation of the degree of atrophy in MS and other spinal cord diseases; and (4) multi-array coils and fast spin echo represent an important advance in MRI of the spinal cord.

Adolescent↗
PubMed1993

Spinal cord MRI using multi-array coils and fast spin echo. II. Findings in multiple sclerosis.

We performed MRI of brain and spinal cord on 80 patients with multiple sclerosis (MS). Using multi-array coils and fast spin echo, 139 intrinsic lesions were identified in 59 patients (74%). Lesions were more common in the cervical than in the thoracic cord. Cross-sectional areas of the cord, measured from axial images at four levels, showed atrophy in 40%. Clinical disability correlated with cord atrophy but not with cord lesion load. These results show that the use of multi-array coils and fast spin echo allows rapid and sensitive detection of spinal cord lesions in MS and that the cord is involved in the majority of patients. A lack of association between cord lesions and disability may relate to limitations in MR resolution but also suggests that the mechanisms of disability in MS are complex and multifactorial.

Adult↗
PubMed1993

Aspiration in acute stroke: a clinical study with videofluoroscopy.

To assess the incidence of lung aspiration in acute stroke, and attempt to identify factors which render such patients at risk of aspiration, consecutive patients admitted to hospital within 24 h of their first symptomatic stroke were studied prospectively. Sixty patients who were conscious, and who did not have any preceding neurological or other cause of dysphagia, were assessed clinically and underwent a bedside water-swallowing test and videofluoroscopy within 72 h of stroke. Twenty-five patients (42%) were seen to aspirate at videofluoroscopy; of these 20% did not have overt dysphagia as detected by a simple water-swallowing test. Factors found to be significantly associated with aspiration were reduced pharyngeal sensation, dysphagia and stroke severity. Aspiration is common in the early period following acute stroke; disordered pharyngeal sensation is an important concomitant of this and should be carefully tested in each patient admitted with acute stroke.

Aged↗
PubMedDate not supplied

Macroscopic and microscopic assessments of disease burden by MRI in multiple sclerosis: relationship to clinical parameters.

We have evaluated macroscopic white matter abnormalities (visible lesions) together with microscopic abnormalities in the normal appearing white matter (NAWM) of patients with multiple sclerosis (MS) to determine their relative contributions to the development of disability. The total visible lesion volume (TLV) was computed as a measure macroscopic changes, whereas both texture analysis and T2 were used as possible indicators of diffuse disease in the NAWM. Dual echo T2-weighted SE images were obtained from 41 patients with definite MS: 10 primary progressive (PP), 11 secondary progressive (SP), 10 benign (BE), 10 early relapsing remitting (ERR), as well as from 10 healthy controls. Calculation of T2 and texture parameters were performed in a region of frontal NAWM of patients and controls. The TLV of each patient was measured using a semiautomated lesion detection program. No significant differences were found between the controls and the patients for all texture parameters examined. However, NAWM T2 was longer in the patients than in the controls (P = .02). Mean TLV was highest for SP and lowest for BE and ERR patients. A significant correlation was found between TLV and EDSS (P < .01) but not between NAWM T2 or texture and expanded disability status score (EDSS). Our study suggest that: (a) diffuse changes are present in NAWM, (b) texture analysis is unable to detect any subtle structure in the NAWM abnormalities, possibly because of the limited image resolution; (c) in the development of disability in MS, macroscopic lesions are more important than microscopic abnormalities in the NAWM.

Adult↗
PubMedDate not supplied

The assessment of handicap: an evaluation of the Environmental Status Scale.

The assessment and measurement of disability and handicap are of particular relevance in rehabilitation, as these are the main foci of therapeutic intervention. The area of handicap is the least developed with few measuring tools to provide an objective assessment of status. The Environmental Status Scale (ESS) is now becoming increasingly utilized to measure handicap. It was used in a study of 50 patients on admission and discharge in a neurorehabilitation unit, to analyse its validity and usefulness as an outcome measure of the rehabilitation process. The results suggest it has limited validity, mixes disability and handicap issues and in some sections has a misleading scoring system. It requires modification to overcome these difficulties.

Disability Evaluation↗