Changes in Cognition and Hemodynamics 1 Year after Carotid Endarterectomy for Asymptomatic Stenosis.

OBJECTIVES: The impact of a change in hemodynamics on cognitive skills in patients with asymptomatic carotid stenosis (ACS) after carotid endarterectomy (CEA) remains unclear. The aim of this study was to evaluate the results of CEA for ACS at 1 year by assessing the changes in anterior, middle, and posterior cerebral artery blood flow in tandem with changes in cognitive efficiency. METHODS: Flow volume in cerebral arteries using quantitative magnetic resonance angiography was measured in a group of 14 males and 5 females before and at 1 year after CEA for ACS. Cognitive efficiency was assessed by Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The values of flow volume were processed using simple ratio (SR) and were used for covariance analyses with changes in cognitive skills after CEA. RESULTS: A significant improvement in cognitive efficiency indexes of immediate memory and visuospatial perception at 1 year after CEA for ACS was observed. Simultaneously, a significant deterioration of speech index was noted. During the analysis of association between flow and cognition, the highest correlation could be seen between the middle cerebral artery (MCA) flow and the visuospatial perception. A change in posterior cerebral artery (PCA) flow was associated with an increase in immediate memory index and anterior cerebral artery (ACA) flow change with the speech index. CONCLUSION: Convergence of data supporting the association between revascularization and cognitive improvement were added in a small, single-center cohort of ACS patients undergoing CEA. No significant differences in cognition were seen between preoperative findings and at 1 year after CEA. Visuospatial perception improvement was linked to flow change in MCA, immediate memory improvement to flow change in PCA, and speech index change to flow change in ACA. Methodical limitations of this small study preclude formulating larger generalizations. Hemodynamic factors in CEA should be assessed in a larger-scale study.

Blood Flow Volume Measurement in Cervical and Intracranial Arteries using Quantitative Magnetic Resonance Angiography and Duplex Sonography (Bocaccia) - A Prospective Observational Study.

PURPOSE: Cerebral blood flow volume is an important factor for the accurate diagnosis of neurovascular diseases and treatment indication. This study aims to assess correlations of blood flow volume measurements in cervical and intracranial arteries between duplex sonography and quantitative magnetic resonance angiography (qMRA). MATERIALS AND METHODS: Consecutive patients with suspicion of cerebral vascular pathology underwent qMRA and duplex sonography of cervical and intracranial arteries with measurement of blood flow volume in bilateral common (CCA), internal (ICA) and external carotid arteries, vertebral and basilar arteries, middle, anterior, posterior cerebral and posterior communicating arteries using 2 different ultrasound machines. Ten patients underwent all examinations twice. Correlations between blood flow volume measurements were evaluated using Spearman's correlation coefficient and inter-class correlation coefficient (ICC). RESULTS: In total, 21 subjects (15 males, mean age: 56.3 ± 6.2 years) were included in the study. Duplex sonography inter-investigator correlation was excellent (ICC = 0.972, p < 0.0001) as well as intra-investigator correlations of both qMRA and duplex sonography (ICC ˃ 0.990, p < 0.0001). Mostly high correlations were recorded between qMRA and duplex sonography in particular cervical arteries but only low to moderate correlations were obtained for intracranial arteries. The mean differences between blood flow volume measurements were 10.9 ±â€Š8.1 % in the CCA and its branches when using qMRA and 15.0 ±â€Š11.9 % when using duplex sonography, 13.5 ±â€Š11.8 %/35.4 ±â€Š34.2 % in the ICA siphon and its branches when using qMRA/duplex sonography, and 24.1 ±â€Š19.7 %/44.9 ± 44.0 % in both vertebral arteries and the basilar artery when using qMRA/duplex sonography. CONCLUSION: Duplex sonography as well as qMRA allow for highly reproducible measurement of blood flow volume in cervical and intracranial arteries in routine clinical practice.

Laser Desorption Ionization Time-of-Flight Mass Spectrometry of Silver-Doped (GeS2)50(Sb2S3)50 Chalcogenide Glasses.

Mass spectra of (GeS2)50(Sb2S3)50 glass and Ag-doped glasses [5% Ag (GeS2)50(Sb2S3)50 and 15% Ag (GeS2)50(Sb2S3)50] obtained using laser desorption ionization (LDI) time-of-flight coupled with quadrupole ion trap mass spectrometry were studied. The analysis of the mass spectra indicated the formation of Ag a Ge b Sb c S d clusters. In addition to the SbS d + (d = 1 and 2), Sb2S d + (d = 1-3), Sb3S d + (d = 1-5), Sb4S d + (d = 3 and 4), Sb5S2 +, and Sb c + (c = 3 and 5) clusters, various clusters containing Ag, such as Ag a + (a = 1 and 2), AgGeS+, AgSb c + (c = 1, 2, and 4), AgSbS+, AgSb2S d + (d = 1-5), AgSb3S3 +, AgSb4S4 +, Ag2Sb3S d + (d = 4 and 5), Ag4Sb2S3 +, and Ag5SbS3 +, were generated. Moreover, in spite of the five-ninth purity of all glass components, several hydrogenated clusters (SbS3H8 +, Sb4S2H+, Ag2H11 +, Ag2Sb3H4 +, Ag3Sb2H4 +, Ag4Sb2H2 +, and Ag4S3H8 +) and some low-intensity oxidized clusters, such as Sb3O+ and Sb3O5 +, were also detected. When applying LDI on (GeS2)50(Sb2S3)50 glass, no Ge-containing clusters were detected in the positive ion mode, and just one Ge-containing cluster was observed after doping the glass with Ag. Hydrogen plays an important role in the glasses studied. The knowledge gained concerning cluster stoichiometry contributes to the elucidation of the structure of Ag-doped Ge-Sb-S chalcogenide glasses. It should be noted that some of the clusters were considered to be structural fragments. Furthermore, mass spectrometry was complemented with Raman spectroscopy.

Urgent Middle Cerebral Artery Embolectomy of Calcified Embolus After Intravenous Thrombolysis: 2-Dimensional Operative Video.

This video shows an urgent microsurgical embolectomy of the inferior division of the left middle cerebral artery in a patient treated by intravenous thrombolysis (IVT). Patient was eligible for endovascular mechanical thrombectomy1; however, the interventional radiologist was not comfortable performing the procedure given prior unsuccessful attempts to remove a calcified cerebral embolus.2 A 75-yr-old female presented with an acute ischemic stroke with isolated aphasia (NIHSS 9). Using the drip-and-ship concept, IVT (0.9 mg/kg rt-PA) was administered in a regional hospital. Fifty-five minutes after a complete recovery following IVT, multiple transient ischemic attacks of aphasia were observed. While the patient was a candidate for mechanical thrombectomy based on CT perfusion imaging, given the unsuccessful reports in the literature and the interventional radiologist's experience, the decision was made to offer microsurgical embolectomy of the calcified cerebral embolus.3 Informed consent for the procedure was obtained directly from the patient. Calcified, crumbly embolus was removed from a 5 mm longitudinal arteriotomy. The arteriotomy was sutured with interrupted 10-0 suture. Initial flow after the embolectomy was 6.5 mL/min. Upon inspection, a distal kink was found in the M2 and after repositioning, flow improved to 35 mL/min. Postoperative CT angiography documented complete recanalization. The clinical findings completely resolved (NIHSS 0) within 12 hr and remained unchanged at 3 mo and 1 yr. Informed consent was obtained from the patient for use of media for educational and publication purposes.

Extended Study on Crystal Growth and Viscosity in Ge-Sb-Se Bulk Glasses and Thin Films.

Crystal growth rates in Ge18Sb28Se54 bulk glass and thin film were measured using optical and scanning electron microscopy under isothermal conditions. The studied temperature region was 255-346 °C and 254-286 °C for bulk glass and thin film, respectively. The compact crystalline layer growing from the surface into the amorphous core was formed in bulk glasses and no bulk crystallization was observed. In the case of thin films, needle-shape crystals were formed. The crystalline layer and needle-shape crystals grew linearly with time that corresponds to a crystal growth controlled by the crystal-liquid interface kinetics. In the narrow temperature range, crystal growth rates exhibit simple exponential behavior, so the activation energies of crystal growth for the studied temperature regions were estimated (EG = 294 ± 6 kJ/mol for bulk glass and EG = 224 ± 12 kJ/mol for thin film). Viscosity of Ge18Sb28Se54 material was measured in the region of the undercooled melt and glass. The extrapolation of viscosity data into the immeasurable, but important, temperature range is discussed. The experimental growth data were combined with melting and viscosity data and the appropriate growth models were proposed to describe crystal growth in a wide temperature region. The standard crystal growth models are based on a simple proportionality of the crystal growth rate to the viscosity (u ∝ η-1). This simple proportionality holds for the bulk material. Nevertheless, in the thin films the decoupling of the crystal growth rate from the inverse viscosity occurs, and the standard kinetic growth models need to be corrected. Such corrections provide better description of experimental data and more realistic value of the parameter describing the mean interatomic distance in the crystal-liquid interface layer, where the crystal growth takes place.

Crystal Growth Kinetics and Viscous Behavior in Ge2Sb2Se5 Undercooled Melt.

Crystal growth, viscosity, and melting were studied in Ge2Sb2Se5 bulk samples. The crystals formed a compact layer on the surface of the sample and then continued to grow from the surface to the central part of the sample. The formed crystalline layer grew linearly with time, which suggests that the crystal growth is controlled by liquid-crystal interface kinetics. Combining the growth data with the measured viscosities and melting data, crystal growth could be described on the basis of standard crystal growth models. The screw dislocation growth model seems to be operative in describing the temperature dependence of the crystal growth rate in the studied material in a wide temperature range. A detailed discussion on the relation between the kinetic coefficient of crystal growth and viscosity (ukin ∝ η(-ξ)) is presented. The activation energy of crystal growth was found to be higher than the activation energy of crystallization obtained from differential scanning calorimetry, which covers the whole nucleation-growth process. This difference is considered and explained under the experimental conditions.