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Biomedical subjects

G Teasdale

Publications and source records attributed to G Teasdale.

At least 19 recordsLinked to original sources
PubMed1992

Computed tomographic and magnetic resonance imaging classification of head injury.

Neuroimaging with CT and MRI is a basis for decision making in individual head-injured patients and also provides a classification of patients according to severity of damage, patterns of injury, pathophysiologic mechanisms and prognosis. Such classifications can be based on the intracranial lesions identified: subdural, extradural, and intracerebral hematomas, contusions, and shearing lesions, or indirect indications of raised intracranial pressure and brain swelling: shift, obliteration of the third ventricle and basal cisterns, and signs of ischemia. The appropriate classification for early diagnosis and acute decision making may differ from the assessment of severity of damage, prognosis and late sequelae. Parallel systems of classification, suitable for these purposes, are proposed.

Brain Edema↗
PubMed1992

A randomized trial of nimodipine in severe head injury: HIT I. British/Finnish Co-operative Head Injury Trial Group.

We studied the efficacy of nimodipine in severely head-injured patients in a randomized study. Of 176 patients who received nimodipine, 2 mg/h iv for 2 day, 53% had a favorable outcome (moderate or good recovery). Of 175 control patients, 49% had a favorable outcome. This difference was not statistically significant but does not exclude the possibility that a study of a larger number of patients could show a clinically useful benefit.

Adult↗
PubMed1991

Pituitary apoplexy and its effect on vision.

A series of 15 patients with a clinical diagnosis of pituitary apoplexy is reviewed. Clinical features are highlighted, with stress on the defects of visual function and ocular motility, and the associated endocrine abnormalities are described. Potential diagnostic errors and their significance are considered. The incidence of this complication in a large series of pituitary adenoma patients is measured, and the radiological and pathological findings are recorded. The results of treatment by surgery and/or radiotherapy and/or bromocriptine are assessed, particularly in relation to visual consequences, and compared with previous reports in the literature, which are reviewed.

Adult↗
PubMed1991

The treatment of head trauma: implications for the future.

The basic aspects of care and organization are going to be most important in these patients: determining who is best suited to provide the care, determining the best treatment, and determining the best venues for treatment. With regard to newer treatments, it will be necessary not only to definitely establish the efficacy of treatment but also to convince the individuals supporting what will be large, expensive trials that this extra benefit is worth the effort and expense required.

Brain Injuries↗
PubMed1990

The effect of nimodipine on outcome after head injury: a prospective randomised control trial. The British/Finnish Co-operative Head Injury Trial Group.

To study the effect of nimodipine on the outcome of head injury, three hundred and fifty-two patients who were not obeying commands were randomised to placebo or nimodipine (2 mg per hour intravenously for 7 days). The 2 groups were well matched for important prognostic features. Six months after injury, more of the patients who were given nimodipine had a favourable outcome (moderate/good recovery) than in the control group, but the increase in favourable outcome (8%) was not significant statistically.

Craniocerebral Trauma↗
PubMed1990

Somatosensory and auditory brain stem conduction after head injury: a comparison with clinical features in prediction of outcome.

Evoked potential conduction times in brain stem auditory (BCT) and central somatosensory pathways (CCT) were recorded from 23 normal subjects and 101 patients with severe head injury. Abnormalities in the CCT and the BCT findings correlated with the clinical indices of brain damage (coma score, motor response, pupil response, and spontaneous and reflex eye movements) in the head-injured patients and each correlated with outcome at 6 months from the injury. The CCT in the "best" hemisphere produced the strongest correlation with outcome (P less than 0.001). The correlation of the CCT with outcome was stronger in the 47 patients examined 2 to 3 days after the injury (P less than 0.001) compared to the 34 patients examined within 24 hours after the injury (P less than 0.02). No such difference was noted for the BCT. Serial studies within the first 2 weeks of injury did not show a consistent pattern and repetition of the investigation over this period did not provide any additional information. We used an INDEP-SELECT discriminant analysis program to determine whether information from the evoked potential data could improve prediction of outcome based on clinical data alone. With the addition of the CCT, the predictive accuracy (expressed as the correct classification probability) increased only slightly from 77 to 80%, and the difference was not significant. We conclude that central somatosensory and auditory brain stem conduction times provide useful prognostic information in paralyzed or sedated patients, but when neurological examination is feasible the benefits of evoked potential analysis do not justify the effort involved in data collection.

Acoustic Stimulation↗
PubMed1990

Efficacy of nimodipine in cerebral ischemia or hemorrhage.

Our studies showed that in an appropriate dose, nimodipine increased local cerebral blood flow with no corresponding increase in local metabolism. Nimodipine treatment given before experimental ischemic insult, resulting from either vascular occlusion or intracranial hemorrhage or after subarachnoid hemorrhage, maintained or improved blood flow and minimized the severity of subsequent brain damage. Lack of benefit from nimodipine treatment after the insult may occur because the inexorable progression of events leading to ischemic neuronal damage, once initiated, cannot be arrested. On the other hand, pharmacokinetic factors may be important, and post-treatment efficacy may depend on administration protocols that achieve an adequate concentration in ischemic tissue sufficiently soon after an insult. Our findings are compatible with the benefit of nimodipine being due to an improvement in blood flow that reduces the severity of ischemia. However, they do not exclude the possibility that treatment may minimize the accumulation of calcium in damaged cells as a result of "cytoprotective" effects.

Animals↗
PubMed1989

Pituitary microadenomas. Does Gadolinium enhance their demonstration?

Ten patients with biochemical evidence of a hormonally active pituitary adenoma were examined by dynamic contrast enhanced computed tomography (CT) and then by pre and post Gadolinium-DTPA (Gd-DTPA) enhanced magnetic resonance imaging (MRI). Excluding one false positive case, CT and unenhanced MRI were comparable in the detection of microadenoma. Post Gd-DTPA examination gave more clear evidence of the actual adenoma in two patients and aided in the demonstration of a third. However, in two others all imaging techniques failed to demonstrate the microadenoma subsequently found at surgery. On the post enhancement MRI it was easier to assess the relationship of a tumour to the cavernous sinus and to visualise the relationships of the parasellar carotid arteries.

Adenoma↗
PubMed1988

Temporal physiochemical changes during in vitro relaxation time measurements: the cerebrospinal fluid.

Documented relaxation time measurements of body fluids such as cerebrospinal fluid (CSF) vary considerably. This may be largely due to lack of an appropriate method of maintaining the in vivo physiological and biochemical characteristics of the fluid. We have developed an in vitro technique that maintains the in vivo characteristics of body fluid samples for a sufficiently long period to establish the true relaxation times. To illustrate this we studied changes in CSF pH, pO2, and pCO2, first as it equilibrated with air and then under anaerobic conditions as found in vivo. Relaxation times of CSF were then studied under aerobic and anaerobic conditions. Under the particular aerobic conditions used the pH and pO2 of CSF increased quickly and pCO2 fell within the first 30 min. By 3-4 h equilibration with air was complete. The T1 and T2 relaxation times of CSF decreased by 14 and 16%, respectively, as a result of these physicochemical changes. It is important that such changes be considered when relaxation measurements of any body fluid are performed in vitro and efforts to maintain the in vivo milieu should not be neglected.

Aerobiosis↗
PubMed1988

Early and late magnetic resonance imaging and neuropsychological outcome after head injury.

Twenty five adults with closed head injury who had early magnetic resonance imaging (MRI) and computed tomography (CT) were followed up 5 to 18 months after injury. Patients were given a repeat MRI and performed a series of neuropsychological tests. They were classified by the deepest abnormality detectable on scanning. Classifications derived from early and late MRI scanning were significantly correlated. However, measures of neuropsychological outcome showed a strong correlation only with late MRI, and little or no relationship with either early MRI or early CT. Deeper abnormalities detected by late MRI were associated with poorer neuropsychological test performance; late ventricular enlargement was particularly associated with poor outcome. It is concluded that the lesions visualised by MRI are important for neuropsychological outcome, and that functionally significant abnormalities may only be fully apparent on late scanning.

Adolescent↗
PubMed1988

Growth hormone, body composition and somatomedin C after treatment of acromegaly.

Acromegaly is associated with abnormal indices of body composition (as determined by exchangeable sodium, exchangeable potassium and total body water estimations) which may be corrected by treatment. We related these indices of body composition to the attained growth hormone levels (mean of five daytime values) in 42 treated acromegalics. Somatomedin C was measured in 30 subjects. The mean duration of treatment was 7.7 years (range 1-26). Exchangeable sodium, potassium and total body water were significantly lowered by treatment. After treatment of acromegaly subjects whose growth hormone level was below 5 mU/l achieved normal body composition more often than those with higher levels. Growth hormone concentration of below 5 mU/l after treatment should be regarded as more appropriate index of control of acromegaly than the higher levels previously recommended.

Acromegaly↗
PubMed1987

Invasive v non-invasive assessment of the carotid arteries prior to trans-sphenoidal surgery.

Imaging studies in 47 patients who were to undergo trans-sphenoidal surgery were analysed with reference to the vascular structures in the parasellar region. The results of cavernous sinography, dynamic contrast enhanced Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) showed good correlation with each other and with the appearances found at operation. CT and MRI, both non-invasive investigations, are therefore reliable preliminary screening methods for identifying the small proportion of patients on whom other imaging techniques need to be performed.

Carotid Artery, Internal↗
PubMed1986

Brain lesions detected by magnetic resonance imaging in mild and severe head injuries.

50 patients were studied by magnetic resonance imaging (MRI) within one week of a head injury. Abnormalities indicating primary brain damage were found in 46 patients, almost twice as many as with computed tomography. Cortical contusions were the most common finding, irrespective of the effect of injury on the level of consciousness. Intracerebral lesions were seen only in patients who had lost consciousness and were present in 29 of 42 patients whose consciousness was still impaired on arrival at hospital. Lesions in the deep white-matter of the cerebral hemispheres were seen in 15 patients; they were significantly more frequent in patients in coma but were also seen in patients who had lost consciousness for no more than 5 min. The findings indicate that lesions in the cerebral hemispheres may be the primary factor in traumatic unconsciousness. MRI studies may also clarify the sequelae of head injuries.

Acute Disease↗
PubMed1986

Use of magnetic resonance imaging to measure intracranial cerebrospinal fluid volume.

Magnetic resonance imaging was used to measure intracranial extraventricular and ventricular cerebrospinal fluid (CSF) volume. In 10 normal subjects lateral ventricular and extraventricular intracranial CSF volumes were 25.3 +/- 4.6 ml (mean +/- SD) and 97.6 +/- 6.6 ml, respectively (total 122.8 +/- 38.7). These volumes were measured in 4 patients and the results were: 11.0 ml ventricular volume, 68.7 ml total cranial CSF in the patient with benign intracranial hypertension; 606.6 ml ventricular, 174.1 ml total in the patient with hydrocephalus due to a blocked ventriculo-peritoneal (V-P) shunt; 83.4 ml ventricular, 108.5 ml total in the patient with normal pressure hydrocephalus; and 52.7 ml ventricular, 181.0 ml total in the patient with cerebral atrophy due to Alzheimer's disease. The technique gave highly reproducible results (SD less than 5.7% of mean value). It may be useful in differential diagnosis and as an objective means of monitoring therapy or progress in conditions such as cerebral atrophy, hydrocephalus, and benign intracranial hypertension.

Adolescent↗
PubMed1986

High-resolution computed tomography in pituitary microadenoma: is seeing believing?

Controversy surrounds the reliability of high-resolution computed tomography (CT) in the identification of functioning microadenomas, especially in patients with hyperprolactinaemia and hypercortisolaemia. We studied 34 such patients: each underwent a high-resolution CT examination of the pituitary gland and each had a trans-sphenoidal exploration. Computed tomography showed 28 focal abnormalities but only 20 of these were confirmed to be due to a tumour at operation. In the other eight the tissue at the site of the radiological abnormality was normal histologically. In a total of 29 patients a tumour was found at operation and confirmed histologically; 20 were at the site of an abnormality shown by CT but in nine a tumour was found in a part of the gland judged to be normal radiologically. In general, good correlation between CT and the surgical findings was found only with tumours more than 6 mm in size. Of the indirect signs of a tumour, such as stalk deviation and a convex upper surface of the gland, only the former showed any correlation with the presence of a tumour. The results show that cautious, even sceptical interpretation of pituitary CT scans is essential and suggest that this investigation is not sufficiently reliable to be used as a routine in the assessment of hyperprolactinaemia or Cushing's syndrome. Computed tomography should be reserved for patients undergoing pituitary surgery, those with an enlarged fossa on plain radiography and those with extreme hormone hypersecretion.

Adenoma↗