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To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion. [ABSTRACT FROM AUTHOR]

Objectives: Cerebral blood flow (CBF) estimates from arterial spin labelling (ASL) show unexplained variability in older populations. We studied the impact of variation of haematocrit (Hct) on CBF estimates in a tri-ethnic elderly population.Materials and Methods: Approval for the study was obtained from the Fulham Research Ethics Committee and participants gave written informed consent. Pseudo-continuous arterial spin labelling was performed on 493 subjects (age 55-90) from a tri-ethnic community-based cohort recruited in London. CBF was estimated using a simplified Buxton equation, with and without correction for Hct measured from blood samples. Differences in perfusion were compared, stratified by sex, ethnicity and diabetes. Results of Student's t tests were reported with effect size.Results: Hct adjustment decreased CBF estimates in all categories except white European men. The decrease for women was 2.7 (3.0, 2.4) mL/100 g/min) (mean (95% confidence interval (CI)), p < 0.001 d = 0.38. The effect size differed by ethnicity with estimated mean perfusion in South Asian and African Caribbean women found to be lower by 3.0 (3.6, 2.5) mL/100 g/min, p < 0.001 d = 0.56 and 3.1 (3.6, 2.5) mL/100 g/min), p < 0.001 d = 0.48, respectively. Estimates of perfusion in subjects with diabetes decreased by 1.8 (2.3, 1.4) mL/100 g/min, p < 0.001 d = 0.23) following Hct correction. Correction for individual Hct altered sample frequency distributions of CBF values, especially in women of non-European ethnicity.Conclusion: ASL-derived CBF values in women, non-European ethnicities and individuals with diabetes are overestimated if calculations are not appropriately adjusted for individual Hct.Key Points: • CBF quantification from ASL using a fixed Hct of 43.5%, as recommended in the ISMRM white paper, may lead to erroneous CBF estimations particularly in non-European and female subjects. • Individually measured Hct values improve the accuracy of CBF estimation and, if these are not available, an adjusted value according to gender, ethnicity or diabetes status should be considered. • Hct-corrected ASL could be potentially important for CBF threshold decision making in the fields of neurodegenerative disease and neuro-oncology. [ABSTRACT FROM AUTHOR]

Purpose: The dilation of the fetal cerebral veins is a rare phenomenon that may be associated to a bad obstetric outcome, and is usually connected to antenatal thrombosis of the posterior dural venous sinuses. There are several descriptions of cerebral vein distension on magnetic resonance imaging (MRI), but all of them are detected postnatally. We present herein two cases of fetal antenatal cerebral dilation of the venous system, without any association to any sign of vein thrombosis, and a systematic review of literature regarding pathogenesis, diagnosis and outcomes associated to the antenatal detection of this condition with the use of MRI.Materials and Methods: To identify potentially eligible studies, we searched PubMed, Scopus, Cochrane Library (all from inception to October 20th, 2016) and applied no language restrictions.Results: The electronic database search provided a total of 22,843 results. After the exclusion of duplicates, manuscripts that resulted not relevant to the review based on title and abstract screening, and analysis of manuscripts eligible for full-text assessment, no papers were found related to the subject reported in the present manuscript.Conclusions: Our report adds importance to MRI as a tool in cases of complex ultrasound finding with the presence of fetal heart failure and deterioration of fetal growth, in order to improve the prognostic evaluation and patient?s counseling. [ABSTRACT FROM AUTHOR]

Introduction. The forming of the blood vessels network configuration at the base of the brain and interconnecting of blood vessels during the embryogenesis is directly related to the phylogenetic development of the brain and brain structures. A blood vessel configuration at the brain base, in the form of a ring or a hexagon, stands in direct relation to the perfusion needs of certain parts of the brain during its primary differentiation. The aim of this paper was to determine the incidence of certain blood vessel configurations at the base of the brain and understanding their symmetry or asymmetry. Methods. Analysis of the blood vessels at the base of the brain was performed on the autopsied subjects. The object of observation was the anterior segment of the circle of Willis consisting of C1-a. carotis interna (ICA), above a. communicaus posterior (PcoA), the segment A1 a. cerebri anterior (ACA) from a. carotis interna bifurcation to the a. communicans anterior (AcoA) and a. communicans anterior itself, as well as the posterior segment consisting of PcoA and the segment P1 -- a. cerebri posterior (PCA) from the a. basilaris bifurcation to the PcoA. For the purpose of grouping the findings, the four basic configuration types of the circle of Willis were identified based on its symmetry or asymmetry. Type-A (symmetric circle of Willis), type-B (asymmetric circle of Willis' due to the unilateral hypoplastic A1-ACA); type-C (symmetric circle of Willis with bilateral symmetric changes on PcoA) and type-D (asymmetric circle of Willis due to the asymmetric changes on PcoA). Results. Autopsy was performed on 56 corpses. A total of 41 (73.2%) subjects were recorded with a symmetric configuration of the circle of Willis', of which 27 (48.2%) subjects had type A and 14 (25%) type C. The asymmetric configuration was present in 15 (26.8%) subjects, of whom 9 (16%) had type B and 6 (10.8%) type D. The symmetric Willis group (73.2%) did not have a homogeneous finding that would fit into the schematic presentation of the symmetric type A and type C. A total of 17 (30.4%) findings were classified in this group of the so-called conditionally symmetric configurations. In all the cases, type B (16%) had unilaterally reduced diameter A1 and hyperplastic AcoA. Conclusion. The presence of asymmetric Willis configuration in 26.8% of the cases, which makes up more than one fourth, indicates that the asymmetric configurations do not represent a pathological form of connecting the blood vessels at the base of the brain, but rather one aspect of its adaptation. The forming of the basic types of configurations of the circle of Willis is associated with a tendency toward certain types of hemodynamic disorders and more frequent pathological changes in places of reduced resistance. [ABSTRACT FROM AUTHOR]

A conference paper about cerebral protection in aortic arch surgery using the straight deep hypothermic circulatory arrest (DHCA) technique. It discusses studies on ascending, descending and thoracoabdominal aortic operations in elective and emergent medical setting, and the cognitive change in patients who used DHCA. A comparison of straight DHCA with retrograde cerebral perfusion (RCP) and antegrade cerebral perfusion (ACP) is offered.