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Biomedical subjects

A Aulich

Publications and source records attributed to A Aulich.

At least 37 records · Page 2Linked to original sources
PubMed1993

Striatal glucose consumption in chorea-free subjects at risk of Huntington's disease.

Controversial data have been reported with regard to the diagnostic value of the positron emission tomographic (PET) measurement of striatal glucose consumption (rCMRGlc) in chorea-free subjects at risk of Huntington's disease (HD). For further clarification of this issue we measured striatal and cerebellar rCMRGlc in 27 chorea-free subjects at risk of HD, 20 patients with manifest HD and 20 control subjects, using PET and 18F-fluorodeoxyglucose. In 6 of the at-risk subjects cerebellar ratios of striatal rCMRGlc were decreased below the corresponding 99% confidence limit determined in the controls. This indicates that the PET measurement of rCMRGlc may, indeed, be valuable in establishing the diagnosis of incipient HD in presymptomatic at-risk subjects.

Adolescent↗
PubMed1993

[Quantification of extracranial carotid stenosis. Magnetic resonance angiography and Doppler sonography versus intra-arterial angiography].

UNLABELLED: To assess various non-invasive techniques for quantifying internal carotid artery CA stenosis, per cent luminal diameter reduction on intraarterial angiograms (IAA) was measured in 63 patients with ICA stenosis or occlusion. These data were compared with independent measurements based on MR-angiography, continuous-wave (cw) Doppler ultrasonography, systolic peak flow velocity and colour Doppler assisted duplex imaging. Correlations with IAA were equally strong for MR angiography, cw Doppler and colour Doppler analysis (0.95; 0.92; 0.92). Positive predictive values for > or = 70% ICA stenosis were lower and negative predictive values were higher for cw Doppler (0.85; 0.92) and colour duplex analysis (0.81; 0.94) than for MR angiography (0.86; 0.88). Statistical analysis showed non-linear correlations between percentage of lumen diameter narrowing and the length of the zone of signal intensity loss (0.72) and maximum systolic peak flow velocity (0.77). CONCLUSION: Several non-invasive methods do compare with IAA in identifying and quantifying high-grade ICA stenosis and may suffice for decisions on treatment.

Adult↗
PubMed1993

[The hemodynamics and anatomy of the circle of Willis. The technic and clinical value of selective MR angiography].

This study evaluates the usefulness of MR angiography in analysing the individual collateral flow dynamics and anatomy of the circle of Willis in 56 patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar area was performed by means of presaturation up to the brain-supplying arteries at the level of the middle neck (angled presaturation slabs). Results obtained with selective and non-selective MRA in 56 consecutive patients were compared with the findings at transcranial Doppler ultrasonography and arterial angiography. Ischaemic cerebral infarctions were classified by computerized tomography and correlated with the results of collateral flow analysis: Sensitivity of selective MRA in detecting intracranial collateral flow via anterior or posterior communicating artery was 96 and 97%, respectively; sensitivity in depicting extracranial transorbital flow was lower (71%). Non-selective MRA was 100% sensitive in detecting a non-filling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Slow flow infarctions occurred more frequently in patients with transorbital and posterior-to-anterior collateral flow than in patients with collateral flow via anterior communicating artery.

Angiography↗
PubMed1992

Magnetoelectrical stimulation of motor cortex in children with motor disturbances.

Transcranial magnetoelectrical stimulation (TMS) is now widely used as a diagnostic tool in adults. In this study we report our experiences with this technique in children with central motor disturbances. We used a Cadwell MES10 magnetoelectrical stimulator with a maximal magnetic field of 2 tesla. The stimulation procedure followed a standardized protocol, with the patients being as relaxed as possible in order to avoid contamination of parameters with different preinnervational levels. Stimulation data were compared to a data base obtained in 58 normal children. The first group of patients consisted of 20 children aged from 7 months to 16 years with hemiparesis of different etiologies. Neuroimaging data were correlated with the results of magnetoelectrical stimulation. In 13 patients a pathological pattern of TMS could be detected, and in 7 of these a corresponding lesion of the cortico-spinal tract was found in CT or MRI scans. In 7 children TMS was normal, in spite of a clear-cut lesion of the cortico-spinal tract in CT or MRI scans in 4 of them. The second group of patients consisted of 16 children with extrapyramidal disease, mostly of hereditary origin, such as DOPA-responsive dystonia or benign hereditary chorea. TMS showed a normal response pattern in this group. We discuss problems and possible pitfalls in TMS in childhood in evaluating the diagnostic value of TMS. At the moment the diagnostic usefulness of TMS in children with motor disturbances appears limited and calls for careful interpretation.

Adolescent↗
PubMed1992

Stroke and dolichoectatic intracranial arteries.

During a 6-year-period, in 45 patients the diagnosis of dolichoectatic intracranial arteries was established. Dolichoectasia of the vertebrobasilar system was the most frequent finding (n = 39). Twenty-two patients presented with brain stem ischaemia, and 10 patients had ischaemic hemispheric events. Six patients had symptoms due to compression of cranial nerves. Hydrocephalus was observed once. Peak and mean flow velocities in 39 patients with dolichoectatic basilar arteries as revealed by transcranial Doppler ultrasound were significantly reduced (p less than 0.00001) when compared with an age-adjusted control group of 20 patients without evidence of vertebrobasilar dolichoectasia on angiogram. Non-invasive MR-angiography offered an excellent imaging of the vascular abnormality. The combined use of CT, TCD, MRI and MR-angiography allows reliable non-invasive diagnosis of dolichoectatic intracranial arteries. This condition seems to play an underestimated role in stroke patients, in particular with respect to the vertebrobasilar circulation.

Brain Ischemia↗
PubMed1990

Transcranial Doppler ultrasonography versus arteriography for assessment of the vertebrobasilar circulation.

The investigation of the vertebrobasilar arterial system by transcranial Doppler (TCD) ultrasonography is difficult due to the numerous anatomical variations in the posterior circulation. To test the validity of TCD, we compared topographic measurements from vertebrobasilar angiograms and corresponding TCD findings in 58 patients with cerebrovascular diseases (N = 37, 21 affecting the vertebrobasilar system), brain tumors (N = 8), and other neurological diseases (N = 13). Normal TCD recordings of the vertebrobasilar system were confirmed by the angiograms in 25 patients, although the noninvasive method failed to separate morphologic variants (N = 15). In patients with pathological conditions of the vertebrobasilar system revealed by either method (N = 17), the combined use of both hemodynamic and radiomorphologic methods improved the diagnostic validity in 24%. We conclude that TCD examination of the posterior fossa circulation provides unambiguous results only if used in combination with cerebral arteriography.

Adult↗
PubMed1990

Normal striatal glucose consumption in two patients with benign hereditary chorea as measured by positron emission tomography.

Positron emission tomography (PET) with [18F]-2-fluoro-2-deoxy-D-glucose (FDG) was used to investigate the regional cerebral metabolic rate of glucose consumption (rCMRGlc) in two patients with benign hereditary chorea (BHC) and 21 normal subjects. Relative and absolute values of cerebellar, striatal, thalamic, and cortical rCMRGlc were within normal limits for both patients with BHC, indicating that the choreic movement disorder encountered in these two patients was not caused by a decrease of energy metabolism in the striatum such as that found regularly in most patients with other forms of chorea (e.g. Huntington's and Wilson's disease).

Adult↗
PubMed1990

Compensatory mechanisms in patients with asymptomatic carotid artery occlusion.

Twelve patients with asymptomatic occlusion of one (n = 8) or both (n = 4) internal carotid arteries were examined by positron emission tomography (PET) and transcranial Doppler ultrasound. PET measurements included the determination of the regional cerebral blood flow (rCBF), oxygen extraction ratio (rOER), cerebral metabolic rate of oxygen (rCMRO2), and cerebral metabolic rate of glucose consumption (rCMRGlc). Transcranial Doppler ultrasound (TCD) was used to determine the pathways and efficacy of collateralization via the circle of Willis and included spectrum analysis of flow velocities within the middle and anterior cerebral arteries as well as vasoreactivity tests. In correspondence with ultrasound evidence of a haemodynamically effective intracranial collateral circulation no significant differences between patients and controls were observed for rOER, rCMRO2 and rCMRGlc, but rCBF was globally reduced. Furthermore, in all patients with unilateral carotid occlusion PET excluded side asymmetries of any parameter studied. In contrast, flow velocity parameters measured by TCD were significantly reduced ipsilateral and significantly increased contralateral to the carotid obstruction. Vasodilative capacities, however, remained preserved even in the territory of the occluded carotid system. These data indicate that patients with asymptomatic carotid occlusion compensate by haemodynamic and not by metabolic mechanisms in contrast to symptomatic patients.

Aged↗
PubMed1990

Cortical and subcortical glucose consumption measured by PET in patients with Huntington's disease.

In 23 patients with moderate to severe Huntington's disease (HD) and 21 normal volunteers, the regional cerebral metabolic rate of glucose consumption (rCMRGlc) was measured in the cerebellum, thalamus, striatum, and cortex using positron emission tomography and the 18F-deoxyglucose method. In contrast to previous reports, rCMRGlc was reduced not only in the striatum, but also in the cerebral cortex of patients with HD as compared with normal subjects. No significant difference between HD patients and normal subjects was found for thalamic and cerebellar rCMRGlc. To investigate the relationship between the clinical status and rCMRGlc, correlation coefficients for the clinical data were calculated for absolute values of rCMRGlc and for cerebellar ratios (CR) of rCMRGlc. The duration of chorea correlated significantly only with the absolute values of frontoparietal and temporo-occipital rCMRGlc and with the CRs of most cortical regions evaluated. The severity of chorea correlated significantly only with lentiform nucleus rCMRGlc. The severity of dementia correlated significantly only with the frontoparietal and temporo-occipital rCMRGlc, the CRs of most cortical regions, and the CR for the caudate nucleus. The degree of disability correlated significantly with the CRs of all regions evaluated except the occipital and the superior frontal cortex. It appears from this study that there is a reduction not only for the striatum but also for cortical rCMRGlc in patients with manifest HD, and that the cortical reduction of rCMRGlc contributes to the severity of clinical symptoms in these patients. This challenges the concept that dementia in HD is of purely subcortical origin.

Adult↗
PubMed1989

[Diagnosis and progress of carotid artery dissecting aneurysm].

33 patients with angiographically confirmed dissection of the internal carotid artery (ICA) were followed prospectively. Cardinal symptoms were: 1) focal disturbances of the cerebral circulation (n = 28); 2) unilateral headache or neck pain (n = 20); 3) incomplete Horner's syndrome (n = 9). Neurological deficits without pain or sympathetic nerve damage developed in 11 patients. All patients had abnormal Doppler ultrasound findings over the ICA; in 22 there were markedly reduced flow velocities and retrograde flow components ("to- and- fro" phenomenon), typical of carotid artery dissection. During a mean observation time of 6.9 +/- 5.7 months serial Doppler ultrasound and angiographic examinations demonstrated recanalization in 73% after an average of 56 days. Angiographically different types (long segments in 13; pseudo-occlusions in 7; pseudoaneurysms in 5; and distal stenoses in 6; others in 2) are interpreted as expressions of different stages in the development of dissection up to complete recanalization.

Adolescent↗
PubMed1989

Doppler color flow imaging of carotid body tumors.

Doppler color flow imaging is a new ultrasound method for the simultaneous spatial display of tissue and vessel morphology (B-mode echotomograms) and of color-coded blood flow velocity information (Doppler-mode analysis). This new method is particularly useful in the neck, not only for the assessment of brain arteries but also for the safe and valid identification of carotid paragangliomas compared with other neck tumors. Early clinical detection of carotid paragangliomas is difficult since these lesions often occur sporadically and the patients remain symptom-free until the tumor becomes noticeable. Doppler color flow imaging allows the diagnosis of even small paragangliomas, which may improve management because of existing complications of surgical therapy.

Adult↗
PubMed1989

Controlled, double-blind study of iosimide, a new, nonionic, monomeric contrast medium, and ioxaglate in cerebral angiography.

Iosimide is a new synthetic, nonionic, monomeric contrast medium in which a new substance, triiodine-trimesine acid, is used. It has definite advantages compared with the basic substances used in the past, diaminobenzoic acid and monoaminoisophthalic acid. Due to the high stability, the possibility of the formation of toxicologically questionable, free nuclei amino compounds disappears. Only the slightest probability of a cross-reaction with present antibodies exists, because of the low frequency in the environment. On the basis of the hydrophilic structure of the side chains, there is only a slight chemotoxicity. In a controlled, double-blind study on 100 randomized patients iosimide was tested in cerebral angiography against ioxaglate. Ioxaglate is an ionic contrast medium, popular because of its low osmolality. In this study iosimide exhibited no differences in comparison with ioxaglate with respect to the contrast, the neurological status or the liver or renal tolerance. In examining cardiovascular tolerance there is only a slight tendency toward liver changes with iosimide. Examination of the general tolerance, however, shows a statistically significant lower incidence of sensation of heat and pain with iosimide than with ioxaglate.

Adult↗
PubMed1988

Usefulness of angioscopy in stenotic processes of the carotid--a comparison with morphological findings.

The development of a new generation of ultrathin flexible fiberscopes permitted direct in-vivo intravascular visualization of pathological changes. But not until the construction of a double-lumen balloon catheter for simultaneous obstruction of the blood flow and rinsing of the vessel did an accurate percutaneous transluminal examination become possible. For testing the usefulness of angioscopic intraluminal diagnosis, 48 carotid arteries from 32 autopsies were examined independently by angioscopy and morphologically. There was a high degree of correspondence between the two methods, especially in cases with low-degree stenosis or complicated plaques, in which other examination methods often fail. Problems of underestimating fibrous plaques and optical projection upstream of the stenosis are discussed.

Arterial Occlusive Diseases↗