Stroke recovery and lesion reduction following acute isolated bilateral ischaemic pontine infarction : a case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Acknowledgements The initial scan was offered as part of the standard clinical service provided by NHS Grampian and the follow-up scan was funded by a grant from the NHS Grampian Endowments Trust (grant number 12/35). We thank Dr Olive Robb, Dr Arnab Rana, Professor Alison Murray for reporting the imaging scans, Lisa Marshall for providing information regarding the patient’s on-going community physiotherapy input following discharge from Aberdeen Royal Infirmary, Gordon Buchan for his technical support during scanning, the research radiographers (Baljit Jagpal, Beverly Maclennan, Nichola Crouch and Katrina Klaasen), the Aberdeen Biomedical Imaging Centre staff especially Teresa Morris and Dawn Younie for coordinating the scanning appointments, the stroke research nurses (Anu Joyson, Heather Gow and Janice Irvine) and above all the patient for agreeing to take part in this case study.Peer reviewedPublisher PD

Dietary nitrate reduces skeletal muscle oxygenation response to physical exercise : a quantitative muscle functional MRI study

© 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.Peer reviewedPublisher PD

Age Related Changes in Cerebrovascular Reactivity and Its Relationship to Global Brain Structure

ACKNOWLEDGMENTS This study was funded by Alzheimer’s Research UK (ARUK) and the Aberdeen Biomedical Imaging Centre, University of Aberdeen. GDW, ADM and CS are part of the SINASPE collaboration (Scottish Imaging Network - A Platform for Scientific Excellence www.SINAPSE.ac.uk). The authors thank Gordon Buchan, Baljit Jagpal, Nichola Crouch, Beverly Maclennan and Katrina Klaasen for their help with running the experiment and Dawn Younie and Teresa Morris for their help with recruitment and scheduling. We also thank the residents of Aberdeen and Aberdeenshire, and further afield, for their generous participation.Peer reviewedPublisher PD

Resting state connectivity and cognitive performance in adults with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Cognitive impairment is an inevitable feature of cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), affecting executive function, attention and processing speed from an early stage. Impairment is associated with structural markers such as lacunes, but associations with functional connectivity have not yet been reported. Twenty-two adults with genetically-confirmed CADASIL (11 male; aged 49.8 ± 11.2 years) underwent functional magnetic resonance imaging at rest. Intrinsic attentional/executive networks were identified using group independent components analysis. A linear regression model tested voxel-wise associations between cognitive measures and component spatial maps, and Pearson correlations were performed with mean intra-component connectivity z-scores. Two frontoparietal components were associated with cognitive performance. Voxel-wise analyses showed an association between one component cluster and processing speed (left middle temporal gyrus; peak −48, −18, −14; ZE = 5.65, pFWEcorr = 0.001). Mean connectivity in both components correlated with processing speed (r = 0.45, p = 0.043; r = 0.56, p = 0.008). Mean connectivity in one component correlated with faster Trailmaking B minus A time (r = −0.77, p < 0.001) and better executive performance (r = 0.56, p = 0.011). This preliminary study provides evidence for associations between cognitive performance and attentional network connectivity in CADASIL. Functional connectivity may be a useful biomarker of cognitive performance in this population

Is There a Difference in Clinical Measures and Structural Magnetic Resonance Imaging Metrics Between Minor Stroke and Migraine Patients?

Background: Patients presenting with minor acute focal neurological symptoms are often diagnosed with minor stroke, transient ischaemic attack, or migraine. Early diagnosis and treatment, in the case of the first two, is important to reduce risk of major strokes. The aim of this study was to assess whether there was a difference in clinical measures and structural magnetic resonance imaging (MRI) metrics between minor stroke and migraine patients. Methods: Twenty-two minor stroke (54.2 ±13.8 years; 10:12 female:male) and twenty-four migraine patients (44.2 ±13.0 years; 12:12 female:male) were enrolled. Clinical measures and structural MRI metrics, the latter extracted with FreeSurfer, were analysed using t test, Pearson correlation coefficient and ordinal regression in SPSS, version 26. The Benjamini-Hochberg post-hoc analysis, with FDR of 0.05, was applied for the t tests and correlations. Results: Systolic (p=0.001, t=3.774), mean arterial (p=0.002, t=3.348), diastolic blood pressure (p=0.009, t=2.721) and pulse pressure (p=0.003, t=3.207) were higher in minor stroke compared to migraine. Grey matter hyperintensities (p=0.002, t=3.350), white matter hyperintensities (p=0.018, t=2.462) and total Scheltens Score (p=0.013, t=2.580) were higher in minor stroke compared to migraine. Left (p=0.007, t=-2.389), right (p=0.009, t=-2.722) and total (p=0.007, t=-2.815) cortical thickness were higher in migraine compared to minor stroke. A significant correlation was observed between pulse pressure and total Scheltens score (r=0.653, p=0.001) in migraine patients. Ordinal regression showed an association between increased age and minor stroke with an odds ratio of 0.948 (95% CI, 0.902-0.996), Wald χ2 (1) = 4.449 p=0.034. Conclusion: The minor stroke results are consistent with current literature. The increased cortical thickness in migraine, could possibly be linked to the cortical spreading theory. This finding and the significant positive correlation between pulse pressure and Scheltens score in migraine warrant further investigation

Brain hyperintensities in magnetic resonance imaging of patients with mild acute focal neurology

Purpose: Hyperintensities are common in neuroimaging scans of patients with mild acute focal neurology. However, their pathogenic role and clinical significance is not well understood. We assessed whether there was an association between hyperintensity score with diagnostic category and clinical assessments/measures. Methods: One hundred patients (51 ± 12 years; 45:55 women:men), with symptomatology suggestive of short duration ischemia referred for magnetic resonance imaging, were prospectively recruited in NHS Grampian between 2012 and 2014. Hyperintensities were quantified, on T2 and FLAIR, using the Scheltens score. Results: The most frequent diagnosis was minor stroke (33%), migraine (25%) and transient ischemic attack (17%). The mean total Scheltens score was 28.49 ± 11.93 with all participants having various loads of hyperintensities. Statistically significant correlations between hyperintensity scores and clinical assessments/measures (age, systolic blood pressure, pulse pressure, MoCA) at the global level were also reflected regionally. These provide further supporting data in terms of the robustness of the Scheltens scale. Conclusion: Hyperintensities could serve as a diagnostic and prognostic imaging biomarker for patients, presenting with mild acute focal neurology, warranting application of automated quantification methods. However, larger cohorts are required to provide a definitive answer especially as this is a heterogenous group of patients

Evaluating an acoustically quiet EPI sequence for use in fMRI studies of speech and auditory processing.

Echoplanar MRI is associated with significant acoustic noise, which can interfere with the presentation of auditory stimuli, create a more challenging listening environment, and increase discomfort felt by participants. Here we investigate a scanning sequence that significantly reduces the amplitude of acoustic noise associated with echoplanar imaging (EPI). This is accomplished using a constant phase encoding gradient and a sinusoidal readout echo train to produce a narrow-band acoustic frequency spectrum, which is adapted to the scanner's frequency response function by choosing an optimum gradient switching frequency. To evaluate the effect of these nonstandard parameters we conducted a speech experiment comparing four different EPI sequences: Quiet, Sparse, Standard, and Matched Standard (using the same readout duration as Quiet). For each sequence participants listened to sentences and signal-correlated noise (SCN), which provides an unintelligible amplitudematched control condition. We used BOLD sensitivity maps to quantify sensitivity loss caused by the longer EPI readout duration used in the Quiet and Matched Standard EPI sequences. We found that the Quiet sequence provided more robust activation for SCN in primary auditory areas and comparable activation in frontal and temporal regions for Sentences N SCN, but less sentence-related activity in inferotemporal cortex. The increased listening effort associated with the louder Standard sequence relative to the Quiet sequence resulted in increased activation in the left temporal and inferior parietal cortices. Together, these results suggest that the Quiet sequence is suitable, and perhaps preferable, for many auditory studies. However, its applicability depends on the specific brain regions of interest. Crow

Oxygen challenge magnetic resonance imaging in healthy human volunteers

Oxygen challenge imaging involves transient hyperoxia applied during deoxyhaemoglobin sensitive (T2*-weighted) magnetic resonance imaging and has the potential to detect changes in brain oxygen extraction. In order to develop optimal practical protocols for oxygen challenge imaging, we investigated the influence of oxygen concentration, cerebral blood flow change, pattern of oxygen administration and field strength on T2*-weighted signal. Eight healthy volunteers underwent multi-parametric magnetic resonance imaging including oxygen challenge imaging and arterial spin labelling using two oxygen concentrations (target FiO2 of 100 and 60%) administered consecutively (two-stage challenge) at both 1.5T and 3T. There was a greater signal increase in grey matter compared to white matter during oxygen challenge (p < 0.002 at 3T, P < 0.0001 at 1.5T) and at FiO2 = 100% compared to FiO2 = 60% in grey matter at both field strengths (p < 0.02) and in white matter at 3T only (p = 0.0314). Differences in the magnitude of signal change between 1.5T and 3T did not reach statistical significance. Reduction of T2*-weighted signal to below baseline, after hyperoxia withdrawal, confounded interpretation of two-stage oxygen challenge imaging. Reductions in cerebral blood flow did not obscure the T2*-weighted signal increases. In conclusion, the optimal protocol for further study should utilise target FiO2 = 100% during a single oxygen challenge. Imaging at both 1.5T and 3T is clinically feasible

Mittelfristige Prognose der österreichischen Wirtschaft 2012-2016: Jahresmodell LIMA/05 ; Ökonometrisches Forschungsprogramm des Instituts für Höhere Studien

aus dem Inhaltsverzeichnis: Einleitung und Zusammenfassung; Die internationale Konjunktur; Die österreichische Außenwirtschaft; Perspektiven der Inlandskonjunktur; Monetäre Prognose; Tabellenanhang

Prognose der österreichischen Wirtschaft 2012-2014: Jahresmodell LIMA/05 ; Ökonometrisches Forschungsprogramm des Instituts für Höhere Studien

aus dem Inhaltsverzeichnis: Einleitung und Zusammenfassung; Die internationale Konjunktur; Die österreichische Außenwirtschaft; Perspektiven der Inlandskonjunktur; Monetäre Prognose; Tabellenanhang