bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure of MK-801 to reduce infarct volume in thrombotic middle cerebral artery occlusion in rats.
Authors: Yao H , Ginsberg M D , Watson B D , Prado R , Dietrich W D , Kraydieh S , Busto R
Published: June 2011

We examined the effects of the noncompetitive N-methyl-D-aspartate receptor antagonist MK-801 using a newly developed stroke model of thrombotic distal middle cerebral artery occlusion under conditions of carefully controlled head temperature.

Male Sprague-Dawley rats were treated with 1 mg/kg of MK-801 or saline before the induction of ischemia. An argon laser-activated dye laser (562 nm) was used to cause thrombotic distal middle cerebral artery occlusion. In experiments 1 and 2, the single laser beam (20 mW) was separated into three beams. Each beam was positioned onto the distal middle cerebral artery at three sites along the vessel. The photosensitizing dye rose bengal (20 mg/kg) was administered intravenously over 2 minutes; the three points were then irradiated for 3 minutes. In experiment 3, higher power of the laser (three separate irradiations using a single beam of 20 mW) was used. The ipsilateral common carotid artery was occluded permanently, and the contralateral carotid artery was occluded for 60 minutes. Head temperature was controlled at 36 degrees C in experiment 1 and not controlled in experiments 2 and 3. Three days after the ischemic insult, brains were perfusion-fixed and infarct volumes were determined.

Head temperature was mildly hypothermic (34-35 degrees C before ischemia, with a further decrease of 1-2 degrees C during the initial 60 minutes of ischemia) in experiment 2. However, no differences were observed in head temperature between the MK-801-treated and control groups. Cortical infarct volume in experiment 1 was 89 +/- 29 mm3 (mean +/- SD) in the treated group, which was not different from the control value of 84 +/- 40 mm3. Infarct volumes were smaller (58 +/- 35 mm3 and 54 +/- 14 mm3) in the control groups of experiments 2 and 3, respectively. However, MK-801 also failed to reduce infarct volumes in experiments 2 and 3.

MK-801 is not effective in this stroke model of focal thrombotic infarction under conditions of either controlled (normothermic) or uncontrolled (mildly hypothermic) head temperature.
Neuroprotection by corticotropin releasing factor during hypoxia in rat brain.
Authors: Fox M W , Anderson R E , Meyer F B
Published: June 2011

Corticotropin releasing factor is an endogenous neuropeptide released by the hypothalamus that activates the pituitary-adrenocortical system in response to stressful stimuli. It has been demonstrated that corticotropin releasing factor increases the excitability of hippocampal neurons in both in vitro and in vivo studies, which may contribute to neurological injury during hypoxia. The purpose of this study was to determine the effects of corticotropin releasing factor and its synthetic competitive antagonist, alpha-CRF, on neuronal synaptic recovery after a hypoxic insult using the hippocampal slice.

Wistar rat hippocampal brain slices (n = 120) were treated with various concentrations (10(-6) to 10(-11)) of corticotropin releasing factor or its synthetic antagonist during a 10-minute hypoxic episode. Extracellular recording of population spikes was used during and after the hypoxic insult to assess neuronal recovery.

Corticotropin releasing factor provided dose-dependent neuronal protection with maximum recovery (37.95 +/- 8.71%) occurring at 10(-9) concentrations. The competitive antagonist alpha-CRF provided a similar degree of recovery at 10(-6) concentration, whereas 10(-9) molar concentration of competitive antagonist resulted in 16.84 +/- 7.68% recovery.

Corticotropin releasing factor provides moderate protection to hypoxic hippocampal neurons in the brain slice preparation. The mechanism of action is unknown but appears to be a direct neuronal effect. These results support the hypothesis that corticotropin releasing factor may act as an endogenous neuroprotective hormone during hypoxia.
Evaluation of the combination of a tissue-type plasminogen activator, SUN9216, and a thromboxane A2 receptor antagonist, vapiprost, in a rat middle cerebral artery thrombosis model.
Authors: Umemura K , Wada K , Uematsu T , Nakashima M
Published: June 2011

We aimed to evaluate a modified tissue-type plasminogen activator, SUN9216, and the combination of SUN9216 and a thromboxane A2 receptor antagonist, vapiprost, in a rat middle cerebral artery thrombosis model.

Under anesthesia, the left middle cerebral artery was observed under an operation microscope without cutting the dura mater via a subtemporal craniotomy. Photoillumination (wave length, 540 nm) was applied to the middle cerebral artery, and then rose bengal (20 mg/kg) was administered intravenously. The reopening of the middle cerebral artery by SUN9216, injected 30 minutes after middle cerebral artery occlusion, was observed under an operation microscope for a 60-minute observation period. Twenty-four hours after the operation, sections of the cerebrum were stained with triphenyltetrazolium chloride, and the area of cerebral infarction was analyzed by a computer.

The combination of SUN9216 and vapiprost caused reopening of the middle cerebral artery in 58.8% of the rats, which was a greater percentage than that achieved with SUN9216 alone (31.6%). In contrast, saline did not cause reopening of the middle cerebral artery during the 60-minute observation period. The area of cerebral infarction in rats reperfused with SUN9216 was significantly reduced compared with that in the control group. The infarction area in rats treated with the combination of SUN9216 and vapiprost was reduced compared with that in rats treated with SUN9216 alone; this was the case whether or not the occlusion was reperfused. There was a significant correlation between the time of reopening of the middle cerebral artery and area of cerebral infarction.

A single injection of SUN9216 was effective in recanalizing the vessel and reducing the area of cerebral infarction.
Transcranial clipping of recurrent cerebral aneurysms after endovascular treatment.
Authors: Ladouceur D L
Published: June 2011

Treatment of intracranial aneurysms by interventional neurovascular techniques may be useful as a therapeutic alternative. We describe two cases of recurrent aneurysms after endovascular treatment using detachable balloons.

Two cases are reported of recurrence 2 years after endovascular treatment of cerebral aneurysms (posterior communicating in both cases). One patient had a subarachnoid hemorrhage after rupture of a posterior communicating aneurysm. The other patient had an aneurysm diagnosed incidentally after a contrast-enhanced computed tomographic scan of the head for an unrelated problem. Endovascular balloon embolization of both aneurysms was performed without any immediate complication. Two years after treatment, a cerebral angiogram showed recurrent aneurysms. Surgical clipping excluded both aneurysms definitely.

These cases highlight the importance of control angiography at long-term follow-up and emphasize the significance of balloon migration after endovascular treatment of aneurysms.
Risk factors for cervical atherosclerosis in patients with transient ischemic attack or minor ischemic stroke.
Authors: Palomäki H , Kaste M , Raininko R , Salonen O , Juvela S , Sarna S
Published: June 2011

Our purpose was to study potential determinants of the presence and the severity of cervical atherosclerosis in patients with transient ischemic attack or minor ischemic stroke.

Two hundred ninety-four patients up to 60 years of age were included in this cross-sectional study. The male to female ratio was 171/123. Atherosclerosis was defined as the presence of any visible atherosclerotic lesion in anteroposterior or left oblique views of cervical arteries in aortic arch angiograms. The severity of atherosclerosis was assessed using three scores, which were computed separately for the total thickness and length of all plaques as well as for the percent stenosis of the vessels.

Atherosclerosis was present in 180 patients (61.2%). In a multiple stepwise logistic regression analysis, age, serum triglycerides, smoking history for more than 20 years, arterial hypertension (defined as systolic or diastolic blood pressure values at least 150 or 100 mm Hg, respectively, or the use of antihypertensive medication), regular light alcohol consumption (inversely), and body mass index (marginal inverse association) were independent determinants of the presence of atherosclerosis; the respective odds ratios were 1.1/1 y, 1.8/1 mmol/L, 3.3, 2.4, 0.3, and 0.9/1 kg/m2. In multiple linear regression models, age was associated positively and the ratio of high density lipoprotein to total cholesterol was associated negatively with the severity of atherosclerosis regardless of the scoring method, whereas current smoking and female sex were predictors only of the percent stenosis and the length of the lesions. Arterial hypertension showed a significant association only with the length of the lesions.

Age, cigarette smoking, and arterial hypertension contribute substantially to atherosclerosis in cervical arteries, but this study also confirms the independent associations of lipid or lipoprotein variables with atherosclerotic disease. An independent inverse association of regular light consumption of alcohol with cervical atherosclerosis was also observed.
Carotid stenosis and perioperative stroke risk in symptomatic and asymptomatic patients undergoing vascular or coronary surgery.
Authors: Gerraty R P , Gates P C , Doyle J C
Published: June 2011

The management of asymptomatic carotid stenosis found before vascular or coronary surgery is unclear from the literature. We aimed to define the relation of carotid stenosis to perioperative stroke in all patients, symptomatic and asymptomatic, and so determine a policy for the management of asymptomatic carotid stenosis in patients requiring major surgery.

We conducted a prospective clinical and Duplex ultrasound study of 358 consecutive noncarotid major vascular or coronary artery bypass operations, with a moratorium on endarterectomy for asymptomatic carotid stenosis.

There were 145 vascular and 213 coronary bypass operations. Ten of the 49 cases with prior symptoms of cerebral ischemia (38 carotid, 11 vertebrobasilar) had symptomatic stenosis of 50% or greater or occlusion, and 3 of these (30%) had ipsilateral perioperative cerebral infarction (95% confidence interval, 6.67% to 65.25%). Two of these occurred ipsilateral to symptomatic carotid occlusions, and 1 occurred ipsilateral to an 80% symptomatic stenosis. One symptomatic patient with bilateral 30% stenosis had a perioperative infarct in the asymptomatic hemisphere. Among the 309 asymptomatic patients, 1 perioperative infarct occurred ipsilateral to carotid stenosis of 30%. In all there were 5 (1.4%) perioperative (within 72 hours) and 2 late (after 18 days) strokes. All strokes were hemisphere infarcts confirmed by computed tomography. There were 53 cases with 50% or greater asymptomatic carotid stenosis or occlusion, including 28 with 80% or greater stenosis or occlusion. None had an ipsilateral perioperative stroke (95% confidence interval, 0% to 6.72%).

We conclude that the risk of perioperative stroke related to symptomatic carotid stenosis may be high, but for asymptomatic carotid stenosis the risk is low and does not justify preoperative prophylactic carotid endarterectomy.
A comparison of five stroke scales with measures of disability, handicap, and quality of life.
Authors: De Haan R , Horn J , Limburg M , Van Der Meulen J , Bossuyt P
Published: June 2011

Recently much debate has arisen on the appropriateness of assessing stroke outcomes with stroke impairment scales. Our purpose was to study the relationship between long-term impairments and functional outcomes in terms of disability, handicap, and quality of life.

We studied 87 patients who had a stroke 6 months earlier. Impairments were scored on five stroke scales: the Orgogozo Scale, the National Institutes of Health scale, the Canadian Neurological Scale, the Mathew scale, and the Scandinavian Stroke Scale. Disability was assessed with the Barthel Index, handicap with the Rankin scale, and quality of life with the Sickness Impact Profile. The linear relationship between stroke scales and functional scales was assessed with correlation coefficients. We used regression analyses to explain functional health.

The stroke scales were highly related to one another (range, r = -.85 to .92). The correlation between stroke scales and functional scales was < .70 and decreased from Barthel (mean r2 = 47.5%) to Rankin (mean r2 = 36.5%) to Sickness Impact Profile (mean r2 = 33%). Stroke scales were rather poorly correlated with patients' psychosocial conditions (mean r2 = 11.5%). Functional health status was mainly related to leg power and orientation. The standardized stroke scale weights of the explanatory items were lower than their standardized regression weights.

Stroke scales only partly explain functional health. The impact of impairments on functional outcomes seems to be underestimated by the stroke scale weights. The correlation patterns give empirical support to the hierarchical structure of the International Classification of Impairments, Disabilities and Handicaps.
Rate of successful recording of blood flow signals in the middle cerebral artery using transcranial Doppler sonography.
Authors: Itoh T , Matsumoto M , Handa N , Maeda H , Hougaku H , Hashimoto H , Etani H , Tsukamoto Y , Kamada T
Published: June 2011

To assess the usefulness of transcranial Doppler sonography, we investigated the rate of blood flow signal recording failure in the middle cerebral artery in Japanese subjects. Furthermore, we studied the effect of increased emitted power on the rate of successful recording in some of the patients in whom recording failure had been detected at the standard transducer power of 100 mW/cm2.

To evaluate the rate of successful recording, we measured blood flow signals in 597 patients (age range, 16 to 89 years) for screening of cerebrovascular disease by using a 2-MHz range-gated, pulsed-wave Doppler instrument at the standard transducer power. In 18 elderly patients with recording failure at the standard power, we assessed the effect of increased emitted power of 400 mW/cm2 on flow signal recording.

Blood flow signals were recorded in 920 (77.1%) of the 1194 middle cerebral arteries of the 597 patients studied. The rate of successful recording of bilateral middle cerebral artery flow signals (70.9%; 423 of 597 patients) decreased with age, especially in females (17.0% in women aged 70 years or older). In 12 of 18 elderly patients with recording failure at the standard power, blood flow signals could be detected at the increased emitted power of 400 mW/cm2.

The rate of successful recording of blood flow signals in Japanese subjects decreases with advancing age, especially in females. Increasing the emitted power markedly improves the successful recording rate.
Measuring carotid stenosis. Time for a reappraisal.
Authors: Alexandrov A V , Bladin C F , Maggisano R , Norris J W
Published: June 2011

Data from recent multicenter carotid endarterectomy trials have questioned the validity and reliability of Doppler ultrasound in the assessment of carotid stenosis.

We prospectively analyzed 45 patients undergoing carotid angiography to compare the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) methods of measuring carotid stenosis with those of direct visualization ("eyeballing") and duplex ultrasound. Linear NASCET and ECST measurements were also converted into area using the pi r2 function and termed "squared NASCET" (N2) and "squared ECST" (E2). In 15 of 45 patients undergoing carotid endarterectomy, the carotid plaque was removed intact, sectioned, and photographed for computer measurement of cross-sectional area. Comparison of this "gold standard" was then made to each method of measurement.

Comparison between duplex and the various angiographic measurement techniques revealed significant differences between NASCET and duplex (P < .0001), ECST and duplex (P < .01), and E2 and duplex (P < .01) but not between N2, eyeballing, and carotid duplex methods. Even the NASCET and ECST methods themselves differed significantly (P < .006). When comparison was made with computerized planimetric measurements of the carotid plaque, there were significant differences for both NASCET (P < .0007) and ECST (P < .007). Correlation was demonstrated only between planimetry and N2, E2, and duplex.

NASCET and ECST angiographic methods of measurement consistently underestimate the "true" anatomic stenosis. As such, they represent only "indexes" of carotid stenosis severity. Duplex provides a more accurate measurement of carotid stenosis.
Carotid artery intimal-medial thickness distribution in general populations as evaluated by B-mode ultrasound. ARIC Investigators.
Authors: Howard G , Sharrett A R , Heiss G , Evans G W , Chambless L E , Riley W A , Burke G L
Published: June 2011

B-mode ultrasound is a widely used technique for the clinical and epidemiological assessment of carotid atherosclerosis. This article provides a description of the distribution of carotid atherosclerosis in the general population.

Intimal-medial arterial wall thickness was measured by B-mode real-time ultrasound as an index of atherosclerotic involvement in the extracranial carotid arteries as part of the population-based Atherosclerosis Risk in Communities (ARIC) study. The distribution was described by race-sex strata, in which 759 to 4952 individuals were imaged depending on strata and location in the carotid system.

Median wall thickness ranged between 0.5 and 1 mm at all ages; fewer than 5% of ARIC participants had values exceeding 2 mm. Individuals tended to have a larger wall thickness in the carotid bifurcation than in the common carotid artery. Internal carotid artery values were more variable, with higher proportions of both large and small wall thicknesses than in the common carotid. The proportion of individuals with a large wall thickness was greatest at the bifurcation and smallest at the common carotid artery. Men had uniformly larger wall thickness than women. Cross-sectional analysis suggests that age-related increases in wall thickness average approximately 0.015 mm/y in women and 0.018 mm/y in men in the carotid bifurcation, 0.010 mm/y for women and 0.014 mm/y for men in the internal carotid artery, and 0.010 mm/y in both sexes in the common carotid artery.

Estimates provided for wall thickness percentiles can serve as "nomograms" by age, race, and sex.
Transcranial color duplex sonography in childhood and adolescence. Age dependence of flow velocities and waveform parameters.
Authors: Schöning M , Staab M , Walter J , Niemann G
Published: June 2011

Transcranial color duplex sonographic examinations in children and adolescents without cerebrovascular disease were evaluated retrospectively. Flow velocities and waveform parameters were determined and their side-to-side differences and age dependence analyzed and, finally, compared with analogous data of a previously described group of healthy adults.

With a 2.0-MHz sector transducer of a computed sonographic system, the anterior, middle, and posterior cerebral arteries were examined in 64 children and adolescents between 1.5 and 17.5 years of age. Angle-corrected systolic peak, end-diastolic maximum, time-averaged, and time-averaged maximum velocities, and the resistance, pulsatility, and spectral broadening indexes were determined in all vessels.

Mean +/- SD values for time-averaged maximum velocity (and time-averaged velocity) were 92.2 +/- 13.0, 79.9 +/- 17.7, and 63.9 +/- 13.6 (55.3 +/- 11.7, 40.4 +/- 10.4, and 34.2 +/- 9.2) cm/s, respectively, in the middle, anterior, and posterior cerebral arteries in children under 10 years of age; values were 83.2 +/- 11.9, 69.4 +/- 13.8, and 55.6 +/- 10.1 (50.8 +/- 9.0, 39.9 +/- 10.5, and 33.1 +/- 6.3) cm/s, respectively, in children 10 years of age and older. Time-averaged maximum velocity decreased significantly with age in all vessels (P < .001). Although time-averaged velocity did not change significantly during childhood and adolescence, a clear decline occurred from adolescence to adulthood (P < .0001 in the middle and posterior cerebral arteries; P < .01 in the anterior cerebral artery). The spectral broadening index decreased significantly from childhood to adolescence in the anterior and posterior cerebral arteries (P < .0001). The resistance and pulsatility indexes remained stable throughout childhood.

Transcranial color duplex sonography allows angle-corrected measurements of "true" flow velocities in basal cerebral arteries. Additional determination of time-averaged velocity permits more detailed evaluation of flow characteristics for all age groups. The transcranial color duplex technique may provide deeper insights on normal cerebral perfusion and its disorders.
Magnetic resonance angiography in vertebrobasilar ischemia.
Authors: Röther J , Wentz K U , Rautenberg W , Schwartz A , Hennerici M
Published: June 2011

Magnetic resonance angiography is a new, noninvasive technique whose diagnostic value in vertebrobasilar artery disease has not yet been determined.

Forty-one patients with acute cerebellar and/or brain-stem ischemia were examined by routine magnetic resonance imaging, extracranial and transcranial Doppler ultrasound, and selective intra-arterial arteriography. Results were correlated with magnetic resonance angiography. Magnetic resonance angiography was accomplished using a three-dimensional time-of-flight gradient-echo technique.

Magnetic resonance angiography correctly identified all occlusions, stenoses, and an aneurysm within the distal vertebrobasilar system as revealed by conventional intra-arterial arteriography but missed the diagnosis of vertebral artery dissection in one case. This results in a sensitivity of magnetic resonance angiography of 97% and a specificity of 98.9%. However, the degree of stenoses was difficult to evaluate by magnetic resonance angiography. At least for severe obstructive lesions, this drawback can be eliminated by application of presaturation pulses, which allow the analysis of flow direction and collateral blood flow. Doppler ultrasound studies add useful hemodynamic information for less severe degrees of stenoses.

The combined use of magnetic resonance angiography and Doppler ultrasound findings may replace the invasive intra-arterial arteriography examination in many patients with suspected macroangiopathy of the vertebrobasilar arteries.
Longitudinal changes in proton magnetic resonance spectroscopy in cerebral infarction.
Authors: Houkin K , Kamada K , Kamiyama H , Iwasaki Y , Abe H , Kashiwaba T
Published: June 2011

Proton magnetic resonance spectroscopy has revealed changes in lactate and N-acetyl-aspartate in acute cerebral infarction. However, the details of these drastic changes and subsequent chronic changes have not been clarified. The purpose of this study was to disclose longitudinal changes in spectra seen in proton magnetic resonance spectroscopy.

Six patients with completed cerebral infarction were examined longitudinally with localized proton magnetic resonance spectroscopy.

(1) In the acute stage (within 2 days after onset), two drastic changes were observed: N-acetyl-aspartate decreased rapidly and severely within 2 days after onset, and lactate increased immediately and reached a high level in the acute stage after onset. (2) In the chronic stage (more than 1 month after onset), two features were observed: lactate, which had increased in the acute stage, remained high for more than 1 month, and other signals such as those of N-acetyl-aspartate, choline, and phosphocreatine/creatine decreased dramatically.

These results suggest that N-acetyl-aspartate and lactate as revealed by proton magnetic resonance spectroscopy can be useful indicators of the ischemic damage to the brain in clinical cases of cerebral infarction.
Silent infarcts in patients with ischemic stroke are related to age and size of the left atrium.
Authors: Mounier-Vehier F , Leys D , Rondepierre P , Godefroy O , Pruvo J P
Published: June 2011

Possible specific risk factors for silent infarcts remain unknown. The aim of this study was to investigate whether risk factors for silent infarcts differ from those for symptomatic infarcts in stroke patients.

Silent infarcts were defined as asymptomatic infarcts detected on computed tomographic scan in patients free of history of stroke and unrelated to the symptoms and signs of the index stroke. Of 595 consecutive patients with stroke or transient ischemic attacks, 116 (19%) had at least one silent infarct on the first computed tomographic scan performed within 24 hours after onset. They were compared with the 479 remaining patients for cerebrovascular risk factors and for presumed mechanism of stroke by means of the odds ratio method. A discriminant analysis was then performed in the subgroup of 216 patients with ischemic stroke who underwent an exhaustive cardiac and vascular workup.

One hundred forty-one silent infarcts (99% confidence interval [CI], 29% to 41%) and 265 symptomatic infarcts (99% CI, 59% to 71%) were subcortical infarcts smaller than 15 mm. Univariate analysis showed that patients with silent infarcts were more likely to be older than 65 years (odds ratio [99% CI], 1.11 to 3.49) and to have left atrial enlargement on echocardiogram (odds ratio [99% CI], 1.02 to 26.70) and leukoaraiosis (odds ratio [99% CI], 1.39 to 4.21). Discriminant analysis found only two independent risk factors for silent infarcts: left atrial enlargement (P = .007) and age older than 65 years (P = .03); leukoaraiosis was not found to be an independent risk factor (P = .86).

Age and left atrial enlargement are the main risk factors for silent infarcts in patients with ischemic stroke or transient ischemic attacks.
Decline in US stroke mortality in the era before antihypertensive therapy.
Authors: Lanska D J , Mi X
Published: June 2011

This study was done to determine if reported declines in stroke mortality in the era before antihypertensive therapy are artifactual.

This study involved analyses of national and state vital statistics data using adjusted and specific rates.

Adoption of the third revision of the International List of Causes of Death in 1921 produced an abrupt 6.6% decrease in stroke mortality rates, but otherwise, changes in disease classification systems had little effect on stroke mortality rates. Adoption of the second revision of the joint-cause manual produced a 9.2% drop in stroke death rates, but other revisions of the joint-cause selection rules had little effect. While rates for the expanding group of states in the death registration area progressively declined, rates for fixed component areas remained constant until around 1925 and then declined. Reselection of the underlying cause from aggregate multiple cause data for 1917, 1925, and 1940 using uniform selection rules confirmed a decline after 1925. Correlation analyses of rates of change for stroke and heart disease rates did not support a shift in diagnosis to explain the divergent trends.

The apparent decline in stroke mortality rates before 1925 is an artifact of changes in disease classification systems, joint-cause selection rules, and nonrandom incorporation of states with different mortality rates into the expanding registration area. The decline after 1925 could not be explained by changes in coding systems or joint-cause selection rules or by a shift in diagnosis from stroke to heart disease.
Subarachnoid hemorrhage without detectable aneurysm. A review of the causes.
Authors: Rinkel G J , van Gijn J , Wijdicks E F
Published: June 2011

In 15% to 20% of patients with a spontaneous subarachnoid hemorrhage, no aneurysm is found on the first angiogram. This review emphasizes that this group of patients is in fact heterogeneous and describes the clinical features, pattern of hemorrhage on early computed tomographic (CT) scan, prognosis, and proposed management in the several and distinct subsets of these patients.

Patients in whom no aneurysm is revealed on the initial angiogram can be subdivided mainly according to the pattern of hemorrhage on an early CT scan. In two thirds of these patients the CT scan shows a perimesencephalic pattern of hemorrhage (ie, blood confined to the cisterns around the midbrain); these patients invariably have a good prognosis, which obviates the need for a second angiogram. Patients with diffuse or anteriorly located blood on CT scan are at risk of rebleeding. In most of these patients the source of hemorrhage is an occult aneurysm, but intracranial artery dissections, dural arteriovenous malformations, mycotic aneurysms, trauma, bleeding disorders, substance abuse, or a cervical origin of the hemorrhage should also be considered. Patients with no blood revealed on an early CT scan but with xanthochromic cerebrospinal fluid are extremely rare. These patients deserve a second reading of the scan for blood in the prepontine cistern, which can be the only site of hemorrhage in perimesencephalic hemorrhage.

The prognosis and management of patients in whom no aneurysm is found on the initial angiogram depends on the pattern of hemorrhage on the initial CT scan. Patients should no longer be designated with the umbrella term "angiogram-negative subarachnoid hemorrhage."
Causes and mechanisms of territorial and nonterritorial cerebellar infarcts in 115 consecutive patients.
Authors: Amarenco P , Lévy C , Cohen A , Touboul P J , Roullet E , Bousser M G
Published: June 2011

Territorial cerebellar infarcts have mainly a thromboembolic mechanism. Cerebellar infarcts less than 2 cm in diameter have recently been reported as nonterritorial infarcts, but it is not clear whether they are low-flow or embolic infarcts. The aim of the present study was to compare the characteristics and causes of territorial and nonterritorial infarcts in a prospective series of 115 patients.

We collected data from 115 consecutive patients with cerebellar infarcts (79 territorial and 36 nonterritorial [ie, less than 2 cm]), using magnetic resonance imaging (88 patients) and computed tomography.

Patients with territorial infarcts and those with nonterritorial infarcts had similar vascular risk factors and clinical presentations and an equal frequency of cardiac source of embolism (32% versus 42%; P = NS) and of large artery occlusive disease (23% versus 19%; P = NS). Occlusive lesions of large arteries at angiography occurred at the level of one cerebellar artery (5% versus 0%; P = NS) and proximal to the ostia of the cerebellar arteries (18% versus 19%; P = NS). Infarcts distal to occlusive lesions were subdivided into unilateral vertebral artery occlusive disease (presumed artery-to-artery embolic mechanism; 18% versus 5%; P = NS) and low-flow state distal to bilateral vertebral or basilar artery occlusion (presumed hemodynamic mechanism; 0% versus 14%; P = .004). Patients with nonterritorial infarcts had more frequent hypercoagulable state (17% versus 1.25%; odds ratio, 15.6 [95% confidence interval, 1.8 to 135]). For the remaining patients, the mechanism of the infarct was unknown (34% versus 22%; P = NS).

Cerebellar infarcts less than 2 cm in diameter (ie, nonterritorial) have the same high rate of embolic mechanism as territorial infarcts (47% versus 49%; P = NS), have more frequent hypercoagulable state, and sometimes have a hemodynamic mechanism.
Stroke rehabilitation outcome. A potential use of predictive variables to establish levels of care.
Authors: Alexander M P
Published: June 2011

The most powerful predictors of functional recovery and eventual home discharge among stroke survivors are the initial severity of the stroke and the patient's age. We analyzed a large population of stroke rehabilitation admissions by stratifying subgroups with coherent outcomes in an attempt to define potentially more efficient patterns of providing rehabilitation care.

We retrospectively analyzed 520 consecutive patients admitted to a rehabilitation hospital (1 calendar year) with cerebral infarction or hemorrhage. Side of index stroke, age, and functional disability at admission were the independent variables. Change in functional disability and home versus nursing home discharge were the dependent measures.

Recovery was overall most closely related to admission severity and age, but the relations between recovery and independent measures were complex. Patients aged < 55 years all were discharged home whatever their initial severity. Patients admitted with modest functional disability were almost all discharged home (96%), whatever their age. For the remainder of the patients, admission severity and age interacted to create two groups with very different prospects for home discharge (P < .0001). Within the groups that eventually returned home, there were very different rates of functional improvement that were directly related to length of hospital stay.

Standard clinical measures available at rehabilitation admission carry enough predictive power to define management strategies for stroke survivors. A management algorithm is proposed that might increase the efficiency of stroke rehabilitation programs and might allow comparisons of efficacy between different treatment settings.
Time course of variations in rabbit cerebrospinal fluid levels of calcitonin gene-related peptide- and substance P-like immunoreactivity in experimental subarachnoid hemorrhage.
Authors: Tran Dinh Y R , Debdi M , Couraud J Y , Creminon C , Seylaz J , Sercombe R
Published: June 2011

Cerebral vasospasm after subarachnoid hemorrhage may result partially from the imbalance between vasodilator and vasoconstrictor factors. The vasodilator peptides substance P and calcitonin gene-related peptide contained in the trigeminovascular system are involved in the vasomotor phenomenon occurring after subarachnoid hemorrhage. The delayed arterial narrowing may reflect the time course of the release of these peptides. Therefore, we followed the time course of the changes in cerebrospinal fluid immunoreactivity of substance P and calcitonin gene-related peptide in a model of experimental subarachnoid hemorrhage.

Cerebrospinal fluid samples were taken in the basal state and at 30 minutes, 24 hours, and 3 days after a single injection of 1 mL autologous arterial blood into the cisterna magna of rabbits using a percutaneous suboccipital route. Substance P-like and calcitonin gene-related peptide-like immunoreactivities were determined in centrifuged cerebrospinal fluid and plasma by use of enzyme immunoassay.

Early (30 minutes) after induced subarachnoid hemorrhage, there was a large increase in cerebrospinal fluid substance P-like immunoreactivity (P < .01) and calcitonin gene-related peptide-like immunoreactivity (P < .01). Arterial and hemorrhagic cerebrospinal fluid levels of substance P-like immunoreactivity were different (P < .03), indicating that the increased cerebrospinal fluid level did not result only from the blood contamination. Twenty-four hours after induced subarachnoid hemorrhage, the immunoreactivities of substance P and calcitonin gene-related peptide remained significantly higher than the basal level (P < .01). At day 3, both immunoreactivities had decreased to a level nonsignificantly different from the basal level.

The early high values of the cerebrospinal fluid immunoreactivities for substance P and calcitonin gene-related peptide, apart from the contamination by arterial blood, probably resulted from the depletion of neurotransmitter peptides from the trigeminovascular fibers.
Estimation of cerebral blood flow through color duplex sonography of the carotid and vertebral arteries in healthy adults.
Authors: Schöning M , Walter J , Scheel P
Published: June 2011

To noninvasively estimate cerebral blood flow volume, a prospective study of color duplex sonography of the common, external, and internal carotid arteries and vertebral arteries of healthy adults was done. Cerebral blood flow was calculated with the sum of flow volumes in the internal carotid and vertebral arteries of both sides.

Using a 7.0-MHz linear transducer of a computed sonography system, cervical arteries of 48 volunteers (23 women, 25 men; mean age, 35 +/- 12 years) were examined. We measured angle-corrected time-averaged velocities and the diameter of the vessels and calculated the flow volumes of all arteries. In addition, peak systolic, maximum end-diastolic, and time-averaged maximum velocities and the resistance, pulsatility, and spectral broadening indexes were determined. Furthermore, we analyzed the side-to-side difference, age dependence, and long-term reproducibility of these parameters.

The mean +/- SD values of flow volumes in the common, internal, and external carotid and vertebral arteries were 470 +/- 120, 265 +/- 62, 160 +/- 66, and 85 +/- 33 mL/min on either side, respectively. Total cerebral blood flow was 701 +/- 104 mL/min (corresponding to 54 +/- 8 mL/100 g per minute), with no variation in age or sex. Long-term reproducibility of cerebral blood flow and flow volumes in all vessels was significant (P < .01).

We conclude that color duplex sonography of cervical arteries is potentially a practical method for estimating total cerebral blood flow. This noninvasive technique may be ideally suited for bedside and follow-up examinations of the critically ill patient. In future studies it should be compared with established radionuclide techniques.
Magnetic resonance imaging of thrombosed dural sinuses.
Authors: Isensee C , Reul J , Thron A
Published: June 2011

Magnetic resonance imaging should have the potential to replace angiography in the diagnosis of dural sinus thrombosis. Concerning time-dependent signal changes of the thrombus, we intended to develop a standardized examination protocol for routine use in suspected dural sinus thrombosis.

The time-dependent signal changes of thrombosed dural sinuses were studied in 23 consecutive patients by multiplanar spin-echo and flow-sensitive sequences. Signal intensities and thrombus homogeneity were graded and related to the time after clinical onset and the results of the magnetic resonance angiography.

Four stages of the thrombus evolution could be observed. The acute thrombosis (days 1 to 5) appeared strongly hypointense in T2-weighted images and isointense in spin density- and T1-weighted images. In the subacute stage (up to day 15) the thrombus signal was strongly hyperintense in T1- and T2-weighted images. The third stage began in the third week after clinical onset. The thrombus signal was decreased in all sequences and showed an increasing inhomogeneity. The fourth (late) stage was characterized by either the restitution of blood flow or the persistence of a residual thrombus.

Each stage requires a different diagnostic approach. With the combined use of spin-echo and gradient-echo sequences, it is possible to make the diagnosis of acute thrombosis; in the second stage, multiplanar spin-echo sequences are sufficient. Diagnosis of dural sinus thrombosis can be established accurately with magnetic resonance imaging in the first two stages. However, the diagnosis of the later stages is difficult because of inhomogeneous signs of recanalization and flow phenomena. Therefore, a suspected older dural sinus thrombus still requires intra-arterial angiography as the primary diagnostic tool.
Relation of carotid artery wall thickness to diabetes mellitus, fasting glucose and insulin, body size, and physical activity. Atherosclerosis Risk in Communities (ARIC) Study Investigators.
Authors: Folsom A R , Eckfeldt J H , Weitzman S , Ma J , Chambless L E , Barnes R W , Cram K B , Hutchinson R G
Published: June 2011

We tested the hypothesis that body mass, waist-to-hip circumference ratio, physical inactivity, diabetes, hyperglycemia, and fasting insulin are each positively associated with asymptomatic carotid artery wall thickness.

Average intimal-medial carotid wall thickness (an indicator of atherosclerosis) was measured noninvasively by B-mode ultrasonography in cross-sectional samples of 45- to 64-year-old adults, both blacks and whites, free of symptomatic cardiovascular disease, in four US communities.

Sample mean carotid wall thickness was approximately 0.7 mm in women (n = 7956) and 0.8 mm in men (n = 6474). Body mass, waist-to-hip ratio, work physical activity, diabetes, and fasting insulin were associated (P < .05) with carotid wall thickness in the hypothesized direction. Adjusted for age, race, smoking, body mass index, artery depth, and Atherosclerosis Risk in Communities field center, mean wall thickness was greater by 0.02 mm in women and 0.03 mm in men for a 0.07-unit (one SD) larger waist-to-hip ratio. Adjusted mean wall thickness was about 0.07 mm thicker in participants with diabetes mellitus and 0.02 mm thicker in participants with hyperglycemia (fasting glucose 6.4 to 7.7 mmol/L) than in subjects with fasting glucose < 6.4 mmol/L. Adjusted mean wall thickness increased by about 0.02 mm with an increase of 100 mmol/L in fasting serum insulin.

Abdominal adiposity, physical inactivity, and abnormal glucose metabolism are associated positively with carotid intimal-medial wall thickness, suggesting these factors contribute to atherogenesis.
Extracranial carotid atherosclerosis and vascular risk factors in different types of ischemic stroke in Taiwan.
Authors: Jeng J S , Chung M Y , Yip P K , Hwang B S , Chang Y C
Published: June 2011

The clinical patterns of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese people are different from those in whites. Studies relating carotid atherosclerosis and vascular risk factors to various types of stroke in Chinese people are lacking.

Based on clinical information, we separated 367 stroke patients living in Taiwan into four subgroups: cortical infarction (CI), subcortical infarction (SCI), vertebrobasilar artery infarction (VBAI), and cardioembolic infarction (CEI). We assessed the extent and severity of extracranial carotid artery atherosclerosis in different types of ischemic stroke using duplex ultrasonography. Vascular risk factors and carotid atherosclerosis were then correlated with each subgroup of ischemic stroke.

Our data revealed that 32% of the CI subgroup, 3% of the SCI subgroup, 7% of the VBAI subgroup, and 21% of the CEI subgroup possessed severe carotid stenosis (> or = 50% stenosis or occlusion). The extent of atherosclerosis of extracranial carotid arteries, measured by plaque score, was also more severe in the CI subgroup than in the other subgroups. Diabetes mellitus was more frequent in the CI subgroup. Cardiomegaly and left ventricular hypertrophy were more commonly seen in the CEI subgroup. The VBAI subgroup was younger than the other subgroups. There were no differences in hypertension, prior stroke, alcohol intake, or serum levels of glucose, uric acid, hematocrit, lipids, and lipoproteins among the subgroups.

Of the Chinese patients living in Taiwan, the extent and severity of extracranial carotid artery atherosclerosis were more prominent in patients with CI than in patients with other types of ischemic stroke. In Chinese patients with CI, severe carotid stenosis is not uncommon; in Chinese patients with SCI, however, the frequency of carotid stenosis is quite low.
Long-term prognosis of symptomatic lacunar infarcts. A hospital-based study.
Authors: Clavier I , Hommel M , Besson G , Noèlle B , Perret J E
Published: June 2011

This study concerns the long-term prognosis of lacunar infarcts.

We report the analysis of our hospital-based series of 178 patients consecutively admitted for a lacunar syndrome due to a lacunar infarct diagnosed with computed tomography and magnetic resonance imaging. Demographic data, medical history, vascular risk factors, and imaging data were recorded for each patient. The follow-up was 35 +/- 22 months.

The lacunar syndrome was pure motor hemiparesis in 69 patients (39%), ataxic hemiparesis in 45 patients (25.4%), pure sensory stroke in 15 patients (8.5%), sensorimotor stroke in 14 patients (7.9%), and miscellaneous syndrome in 34 patients (19.2%). The 4-year survival rate was 80 +/- 4% and the 4-year survival rate without recurrent stroke was 85 +/- 3.5%. Using Cox proportional-hazards analysis, the predictors of death were age (P < .02), diabetes mellitus (P < .05), and cigarette smoking (P < .05). We did not find any predictors of recurrence. After 1 year, 74% of the patients had mild or no disability. Using logistic regression analysis, the predictive factors of disability were age more than 70 years (P < .01), diabetes (P < .01), history of stroke or transient ischemic attack (P < .05), and type of lacunar syndrome (P < .01). Imaging data, number of lacunes, and presence of leukoaraiosis were not predictors of outcome.

Our study suggests that with a high survival rate, a low recurrence rate, and a relatively good functional recovery, lacunar infarcts have a relatively favorable prognosis.
On the inheritance of intracranial aneurysms.
Authors: Schievink W I , Schaid D J , Rogers H M , Piepgras D G , Michels V V
Published: June 2011

The familial occurrence of intracranial aneurysms suggests the presence of a genetically determined underlying arteriopathy. The pattern of inheritance in these families usually is not known.

A family with seven members with intracranial aneurysms is described and, from the literature before 1994, a total of 238 families with 560 affected members (56% female and 44% male) with intracranial aneurysms not associated with a known heritable disease are reviewed. A segregation analysis was performed on 73 of these families.

Two members were affected in the great majority of families (79%); five or more members were reported in only eight families (3%). The most common affected kinship was among siblings. Angiographic screening in 12 families detected an intracranial aneurysm in 29% of 51 asymptomatic relatives. Segregation analysis revealed several patterns of inheritance that were consistent with the compiled pedigrees, but no single mendelian model was the overall best fitting, suggesting that genetic heterogeneity may be important. Twenty-two percent of siblings of male probands had an intracranial aneurysm compared with 9% of siblings of female probands (P = .003).

Genetic heterogeneity may be important in the genetics of intracranial aneurysms. In families with intracranial aneurysms, siblings of an affected male proband may be at a higher risk of developing an aneurysm than siblings of an affected female proband. Screening for intracranial aneurysms in asymptomatic relatives should be considered in families with two or more affected members. In most families, the nature of the underlying arteriopathy remains obscure.