bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.