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D Leys

Publications and source records attributed to D Leys.

At least 127 records · Page 7Linked to original sources
PubMed1998

Contrast-enhanced three-dimensional fast imaging with steady-state precession (FISP) MR angiography of supraaortic vessels: preliminary results.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the effectiveness of contrast-enhanced fast three-dimensional (3D) MR angiography in depicting both the carotid and vertebral arteries in their cervical portions and to compare MR angiography with conventional angiography for the evaluation of arteriosclerotic disease. METHODS: Twenty-seven patients with ischemic cerebral events in the anterior (n = 18) and posterior (n = 9) circulation underwent contrast-enhanced 3D MR angiography in the coronal plane. MR angiograms were examined in a blinded fashion by two observers independently. Stenosis was classified according to the appearance of the residual lumen (no stenosis, mild stenosis, moderate stenosis, severe stenosis, occlusion). Conventional angiography was used as the standard of reference. RESULTS: Proximal great vessels and carotid siphons were not assessable on MR angiograms in 35% of cases owing to limited coverage. All cervical and petrous segments of the internal carotid arteries (ICAs) and 93% of the extracranial vertebral arteries were assessable. Flow-related artifacts were observed in seven cases of severe stenosis, including three with signal void at the site of narrowing and four with signal loss in the distal ICA. Interobserver agreement was good and significant. Overall agreement between 3D MR angiography and conventional angiography was good for the anterior and posterior circulations despite a tendency toward overestimation of stenoses on MR angiograms. Clinically relevant stenoses and occlusions were correctly identified on 3D MR angiograms, providing good sensitivity and specificity. CONCLUSION: Contrast-enhanced 3D MR angiography is a promising tool for assessing arteriosclerotic lesions of supraaortic vessels. Further studies with larger groups are required to determine its value for patient care.

Adult↗
PubMed1998

[Blood pressure and Alzheimer's disease].

To fulfill criteria for probable Alzheimer's disease (AD), patients must be free of cerebrovascular lesions that may explain the cognitive decline. These criteria probably lead to an underestimation of the links between risk factors for stroke and AD. However, the association between stroke and AD is probably more frequent than expected. Arterial hypertension is the most important risk factor for stroke. The aim of this study is to evaluate, from the literature, the possible relationship between blood pressure and AD. Cognitive performances are usually lower in patients with arterial hypertension. A longitudinal study revealed that patients with AD aged 79-85 are more likely to have had higher values of blood pressure 10 to 15 years earlier, and they usually have a spontaneous decline of blood pressure beginning 1 or 2 years before the onset of AD. The relationship between arterial hypertension and AD is probably due to the summation of Alzheimer pathology, white matter changes and cerebrovascular lesions. A possible consequence of these findings would be to prevent, or to postpone, AD by an early treatment of arterial hypertension. This is currently evaluated in drug trials.

Adrenergic Fibers↗
PubMed1997

Why are stroke patients prone to develop dementia?

Stroke patients are more likely to develop dementia than age- and sex-matched controls but the pathogenesis of dementia remains unresolved in most of them. The aim of this review is to determine, from the available literature, the theoretical reasons for a stroke patient to become demented. We found three distinct factors that may explain the occurrence of dementia after a stroke. Firstly, post-stroke dementia may be the direct consequence of the vascular lesions of the brain: this is the most likely cause in patients with normal cognitive functions before a strategic infarct, especially in young patients, in Icelandic-type hereditary amyloid angiopathy and in cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy. Secondly, post-stroke dementia may be due to an associated asymptomatic Alzheimer pathology; the reasons for such an association are that (1) some cases of dementia occurring after a stroke are progressive and Alzheimer's disease (AD) is the most frequent cause of progressive dementia; (2) age and APOE epsilon 4 genotype are risk factors for both AD and ischaemic stroke; (3) a vasculopathy is often associated with AD. Lastly, white matter changes may also contribute to dementia because they often indicate small-vessel disease and a higher risk of stroke recurrence, and may lead to slight cognitive impairment. Finally, the summation of vascular lesions of the brain, white matter changes, and Alzheimer pathology might lead to dementia, even when each type of lesion, on its own, is not severe enough to induce dementia. Therefore, in patients followed up after a stroke, the term "post-stroke dementia" is probably more appropriate than that of vascular dementia because it includes all possible causal factors.

Aged↗
PubMed1997

Cervical artery dissections.

Cervical artery dissection (CAD) accounts for up to one fifth of ischemic strokes occurring before 45 years. Their increasing recognition is probably due to an increased clinical awareness of this condition in patients with painful ischemic events. The internal carotid artery is the most commonly affected vessel. Cerebral ischemia is the most serious consequence of a CAD. It may be due to hemodynamic factors or emboli. The enlargement of the artery may lead to a direct compression of the lower cranial nerves. CAD typically occurs in young adults with a mean age of 40 years with a male:female ratio of 1.5. After exclusion of traumatic cases, the average annual incidence rate of CAD is 2.6 per 100,000, but the reported incidence figures in the literature are likely to be an underestimation of the incidence of CAD. A spontaneous dissection is assumed when no or only minor trauma preceded the onset. However, the differentiation between spontaneous and traumatic dissections is artificial because of a continuum between both forms. The pathogenesis of dissections remains unknown in most cases. However, traumas and primary diseases of the arterial wall are the main predisposing factors. The clinical presentation of spontaneous dissections of the internal carotid artery includes cerebral ischemia, cervical or cranial pain, Horner's syndrome and cranial nerve palsy; CAD may also be silent. Brainstem ischemic deficits and occipital pain are the most common findings in vertebral artery dissections, but these features may be biased because the most benign and the most severe cases may escape detection. The favorable natural history of CAD emphasizes the need for a noninvasive approach to the detection, monitoring and follow-up. This noninvasive approach can be obtained by means of CT scan, MRI, magnetic resonance angiography and ultrasonography, although angiography remains the gold standard for the diagnosis of arterial dissections. Follow-up studies suggest a fairly good overall prognosis in adults and in children. In many centers, CAD are treated by heparin at the acute stage, although the benefit of such a potentially dangerous treatment has never been proven by a randomized trial.

Adult↗
PubMed1997

Qualitative assessment of cerebral atrophy on MRI: inter- and intra-observer reproducibility in dementia and normal aging.

To assess the reproducibility of a qualitative rating scale of cerebral atrophy on MRI in an aged population of demented and non-demented individuals, 4 raters independently judged cerebral atrophy (CA) in 13 regions on a 0-3 scale on 75 MRI scans, on two occasions. The level of agreement was expressed by kappa statistics as well as by analysis of variance for interexaminer reproducibility studies. The mean CA scores ranged from 13.3 to 21.2, indicating moderately high prevalence of cerebral atrophy in this sample. Complete agreement among observers was reached in 49.7% of the ratings during the first assessment and in 44.1% in the second assessment. The inter-observer agreement was poor in both sessions (mean overall kappas 0.34 and 0.24). The intra-observer agreement was moderate to good for all raters (mean overall kappa: 0.58). The average standard deviation of the differences between CA scores of the 4 raters was 5.12 in the first and 5.13 in the second session. The average standard deviation for the differences within raters was 2.4. We conclude that the assessment of cerebral atrophy using this rating scale on MRI in an aged population has a poor reproducibility among raters. However, it provides regional atrophy measurements and is quite reliable when performed by a single rater.

Aged↗
PubMed1997

Preexisting dementia in stroke patients. Baseline frequency, associated factors, and outcome.

BACKGROUND AND PURPOSE: The link between stroke and degenerative dementia, especially Alzheimer's disease, is closer than expected by chance. Dementia after stroke may be due to the cumulative effect of vascular and degenerative changes. The prevalence of dementia just before stroke onset remains unsettled. The aim of this study was to determine the frequency of preexisting dementia in stroke patients, associated factors, and consequences on outcome. METHODS: We evaluated the cognitive functioning prior to stroke in 202 consecutive patients with ischemic or hemorrhagic stroke by means of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). We classified in the dementia group patients with IQCODE scores of 104 or more. Six months after stroke onset, survivors underwent a battery of neuropsychological tests. RESULTS: Thirty-three patients were demented before stroke (16.3%; 95% confidence interval, 11.2 to 21.4). There was no diagnosis of dementia in 32 of these 33 patients. We determined by logistic regression analysis that female sex, family dementia, leukoaraiosis, and cerebral atrophy are independently associated with prestroke dementia. All survivors who had IQCODE scores of 104 or more at the acute stage met criteria for dementia 6 months later. CONCLUSIONS: Our study showed that one sixth of stroke patients have preexisting dementia. Therefore, some patients with so-called "poststroke dementia" probably had unrecognized preexisting dementia.

Adult↗
PubMed1997

Arterial ischemic strokes associated with pregnancy and puerperium.

Physiological changes occurring during pregnancy and puerperium may increase the risk of stroke. However, the incidence rate of ischemic stroke is of 3.8 to 5 in 100,000 pregnancies, i.e. quite similar to that of ischemic strokes occurring in non pregnant women of child bearing age. Whereas eclampsia, choriocarcinoma and amniotic emboli occur only during pregnancy or puerperium, peripartum cardiomyopathy and benign cerebral angiopathy are less specific. All other causes of cerebral ischemia may also occur during pregnancy and puerperium. The management of an ischemic stroke should not differ between pregnant and non pregnant women of child bearing age. Strokes associated with pregnancy require a complete diagnostic work-up including angiography if necessary. Low doses of aspirin (60-80 mg/d) can be used after 3 months of pregnancy. Heparin is the anticoagulant of choice during pregnancy, but warfarin may be used between 13 and 36 weeks of gestation; heparin and warfarin can be used during breast feeding. There is no neurological reason to recommend a systematic use of cesarean section. Subsequent prescription of oral contraceptive therapy is not recommended except in patients with a definite cause of ischemic stroke which is not influenced by hormones.

Arterial Occlusive Diseases↗
PubMed1997

Is positron emission tomography useful in stroke?

Positron emission tomography (PET) has been widely used in the study of stroke and related cerebrovascular diseases. It has shown the various stages leading to cerebral infarction and defined the significance of the ischaemic penumbra. PET scan can predict the clinical outcome of patients with acute ischaemic stroke. Several types of diaschisis can also be demonstrated by PET. They reflect different pathophysiological changes in supratentorial infarcts. Post-apoplectic seizures are shown to increase the ischaemic damage in the affected cerebral hemisphere. PET has contributed also to the concept of multi-infarct dementia, although the significance of chronic ischaemia in the pathogenesis of vascular dementia has not been fully investigated.

Brain Ischemia↗
PubMed1996

Atherosclerotic disease of the aortic arch as a risk factor for recurrent ischemic stroke.

BACKGROUND: Atherosclerotic disease of the aortic arch is found in 60 percent of patients 60 years of age or older who have had brain infarction. The aim of this study was to determine whether atherosclerotic plaques in the aortic arch are a risk factor for recurrent brain infarction and for vascular events in general (i.e., brain infarction, myocardial infarction, peripheral embolism, and death from vascular causes). METHODS: For a period of two to four years, we followed a cohort of 331 patients 60 years of age or older who were consecutively admitted to the hospital with brain infarction (a total of 788 person-years of follow up). All patients underwent transesophageal echocardiography to determine whether atherosclerotic plaques were present in the aortic arch proximal to the ostium of the left subclavian artery. The patients were divided into three groups according to the thickness of the wall of the aortic arch ( < 1 mm, 1 to 3.9 mm, and > or = 4 mm). RESULTS: The incidence of recurrent brain infarction was 11.9 per 100 person-years in patients with an aortic-wall thickness of > or = 4 mm, as compared with 3.5 per 100 person-years in patients with a wall thickness of 1 to 3.9 mm and 2.8 per 100 person-years in patients with a wall thickness of < 1 mm (P < 0.001). The overall incidence of vascular events was 26.0, 9.1, and 5.9 per 100 person-years of follow-up in the respective groups (P < 0.001). After adjustment for the presence of carotid stenosis, atrial fibrillation, peripheral arterial disease, and other risk factors, aortic plaques > or = 4 mm thick (including the thickness of the aortic wall) were found to be independent predictors of recurrent brain infarction (relative risk, 3.8; 95 percent confidence interval, 1.8 to 7.8; P = 0.0012) and of all vascular events (relative risk, 3.5; 95 percent confidence interval, 2.1 to 5.9; P < 0.001). CONCLUSIONS: Atherosclerotic plaques > or = 4 mm thick in the aortic arch are significant predictors of recurrent brain infarction and other vascular events.

Aged↗
PubMed1996

Risk factors and leukoaraiosis in stroke patients.

OBJECTIVES: Although leukoaraosis (LA) is a common CT findings, its pathogenesis remains debated: if small-artery pathology may explain in some cases white matter changes, many other factors, such as hemodynamic perturbations, might also lead to LA. To test these hypothesis, we determined the types of cerebrovascular risk factors associated with leukoaraosis in consecutive patients with acute cerebrovascular event. PATIENTS AND METHODS: Using CT-scans, we prospectively studied in 610 patients consecutively admitted for an acute cerebral event, the relation between LA and the following cerebrovascular risk factors: age, sex, arterial hypertension, diabetes mellitus, hyperlipemia, alcohol consumption, birth contraceptive pills, previous transient ischemic attack or stroke, migraine, atrial fibrillation, valvulopathy, coronaropathy, left ventricular hypertrophy, stenosis of the internal carotid artery, by means of a multiple linear regression. Relation with cerebral atrophy was also evaluated. RESULTS: We found LA scores to depend on increasing age (p = 0.0001), female sex (p = 0.0146), history of stroke or TIA (p = 0.0051), history or current atrial fibrillation (p = 0.0083), increasing cerebral atrophy score (p = 0.0001), absence of hyperlipemia (p = 0.0003) and absence of alcohol consumption higher than 300 g/week (p = 0.0398). CONCLUSION: Our findings do not support the hypothesis that, in stroke patients, LA share similar risk factors than small-vessel disease; other cerebrovascular risk factors may also contribute to LA, perhaps because of decreased cerebral blood flow.

Adolescent↗
PubMed1996

Inter- and intraobserver reproducibility of cerebral atrophy assessment on MRI scans with hemispheric infarcts.

Cerebral atrophy (CA) in stroke patients is associated with poststroke dementia and may reflect underlying neurodegenerative pathology. Therefore, regional CA may be valuable to study in patients who develop poststroke dementia. The aim of this study was to test the reproducibility of a qualitative rating scale of CA on MRI. MRI scans were performed in 50 consecutive patients (age range 19-81) admitted for an acute hemispheric ischemic stroke. CA was assessed on 2 occasions 24 h apart, on axial T2-weighted sequences by 4 independent observers. We evaluated CA in 13 regions on a 0-3 scale. The sum of the subscores was called the CA score (range: 0-39). The level of agreement was expressed by kappa statistics as well as by analysis of variance for interexaminer reproducibility studies. The mean CA scores ranged from 2.8 to 11.0, indicating the low prevalence of CA in this sample. Complete agreement was reached in 41.7% during the first assessment and in 44.1% in the second assessment. The interobserver agreement was moderate in the first session (mean overall kappa: 0.48) and substantial in the second (mean overall kappa: 0.67). The intraobserver agreement was good for all raters (mean kappa: 0.65). Standardized to the range of the scale, standard deviations of the differences between CA scores of the 4 raters in the 2 sessions were 11.1 and 11.2%; within raters it was 4.4%. We conclude that the assessment of CA using this rating scale is possible in stroke patients. It provides regional atrophy measurements and is reproducible when performed by 1 rater.

Adult↗
PubMed1996

Helical CT for the diagnosis of extracranial internal carotid artery dissection.

BACKGROUND AND PURPOSE: We attempted to evaluate the sensitivity of helical CT for the diagnosis of extracranial internal carotid artery (ICA) dissection. METHODS: Sixteen consecutive patients with 18 angiographically confirmed extracranial ICA dissections were studied with a helical CT protocol with large-volume acquisition and thin axial slice reconstructions. A control group including normal and atherosclerotic ICAs was formed for comparison, and a blind interpretation of CT images was made by two observers. We evaluated the presence of stenosis, eccentric lumen, mural thickening, aneurysm, occlusion, and annular contrast enhancement. When the artery seemed to be occluded, we measured the external diameter of the ICA (1) on the occluded side, at its upper portion and most enlarged level, (2) at its lower portion, beyond the bulb, and (3) on the contralateral side, at is upper portion. RESULTS: Interobserver agreement was good except for the presence of annular contrast enhancement. In the stenotic dissection group (n=12), the presence of a narrowed eccentric lumen at the upper portion of the ICA on axial CT images was classified correctly in all cases (sensitivity, 100%; specificity, 100%). An arterial wall thickening was seen in all cases of dissection but also in three cases of the control group. In the occlusive dissection group (n=6), the enlargement of the dissected artery was the best criterion (sensitivity, 100%, specificity, 100%) for occlusive dissection. CONCLUSIONS: Helical CT seems to be a reliable method for evaluating extracranial ICA dissection. The analysis of the residual arterial lumen and the measurement of the external diameter of the carotid artery were the best criteria for the diagnosis. Further studies with larger groups are required to determine whether ICA dissections might be diagnosed using helical CT as a first procedure.

Adult↗
PubMed1996

Dementia in stroke.

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Cerebrovascular Disorders↗
PubMed1996

Cranial nerve palsies due to internal carotid artery dissection: seven cases.

Cranial nerve palsies are rare complications of internal carotid artery (ICA) dissections. The aim of this study is to evaluate the incidence of cranial nerve palsies in consecutive patients with ICA dissection and to describe clinical and radiological characteristics and their evolution over time. This study was conducted in 52 consecutive patients with dissection of the ICA. We have analyzed clinical data of patients with cranial nerve palsy as complication of ICA dissection. We defined ICA dissection as angiographic evidence of a string sign, double lumen, or internal flaps or visualization on magnetic resonance imaging (MRI) or computed tomographic scans of an enlarged arterial wall due to the hematoma. Of 52 consecutive patients with ICA dissection 7 had cranial nerve palsies: 2 had an involvement of the Vth cranial nerve and 5 had lower cranial nerve palsies. Five patients totally recovered while 2 did not after a 2 to 10-month period. The frequency of cranial nerve palsies associated with ICA dissection is higher in our study than in those of the literature. Many patients presenting with cranial nerve palsies due to ICA dissection without any ischemic event are probably not referred to stroke units. Angiography is less sensitive than cervical MRI to detect such patients. Cranial nerve palsies could either be due to compression by the enlarged ICA wall or an ischemia of the nerve.

Adult↗