OBJECTIVES: The objective of this work was to compare quantification techniques for CEST imaging that specifically separate APT and NOE effects for application in the clinical setting. Towards this end a methodological comparison of different CEST quantification techniques was undertaken in healthy subjects, and around clinical endpoints in a cohort of acute stroke patients.
METHODS: MRI data from 12 patients presenting with ischaemic stroke were retrospectively analysed. Six APT quantification techniques, comprising model-based and model-free techniques, were compared for repeatability and ability for APT to distinguish pathological tissue in acute stroke.
RESULTS: Robustness analysis of six quantification techniques indicated that the multi-pool model-based technique had the smallest contrast between grey and white matter (2%), whereas model-free techniques exhibited the highest contrast (>30%). Model-based techniques also exhibited the lowest spatial variability, of which 4-pool APTR∗ was by far the most uniform (10% coefficient of variation, CoV), followed by 3-pool analysis (20%). Four-pool analysis yielded the highest ischaemic core contrast-to-noise ratio (0.74). Four-pool modelling of APT effects was more repeatable (3.2% CoV) than 3-pool modelling (4.6% CoV), but this appears to come at the cost of reduced contrast between infarct growth tissue and normal tissue.
CONCLUSION: The multi-pool measures performed best across the analyses of repeatability, spatial variability, contrast-to-noise ratio, and grey matter-white matter contrast, and might therefore be more suitable for use in clinical imaging of acute stroke. Addition of a fourth pool that separates NOEs and semisolid effects appeared to be more biophysically accurate and provided better separation of the APT signal compared to the 3-pool equivalent, but this improvement appeared be accompanied by reduced contrast between infarct growth tissue and normal tissue.
AIM OF THE STUDY: To assess the motor and cognitive effects of acute oral administration of CT root methanolic extract and hippocampal long-term plasticity in the CA1 region of the CCH rat model.
MATERIALS AND METHODS: Male Sprague Dawley rats (200-300 g) were subjected to permanent bilateral occlusion of common carotid arteries (PBOCCA) or sham operation. Then, these rats were given oral administration of CT root extract at doses of 100, 200 or 300 mg/kg on day 28 post-surgery and tested using behavioural tests (open-field test, passive avoidance task, and Morris water maze) and electrophysiological recordings (under urethane anaesthesia).
RESULTS: Treatment with CT root extract at the doses of 200 and 300 mg/kg resulted in a significant enhancement in memory performance in CCH rats induced by PBOCCA. Furthermore, CCH resulted in inhibition of long-term potentiation (LTP) formation in the hippocampus, and CT root extract rescued the LTP impairment. The CT root extract was confirmed to improve the glutamate-induced calcium increase via calcium imaging using primary cultured rat neurons. No significance difference was found in the CaMKII expression. These results demonstrated that CT root extract ameliorates synaptic function, which may contribute to its improving effect on cognitive behaviour.
CONCLUSIONS: Our findings demonstrated an improving effect of CT root extract on memory in the CCH rat model suggesting that CT root extract could be a potential therapeutic strategy to prevent the progression of cognitive deterioration in vascular dementia (VaD) and Alzheimer's disease (AD) patients.
METHODS: We included ischaemic stroke cases admitted to Sarawak General Hospital between June 2013 and August 2018 from Malaysia National Stroke Registry. We performed descriptive analyses on patient demographics, cardiovascular risk factors, prior medications, smoking status, arrival time, thrombolysis rate, Get With The Guidelines (GWTG)-Stroke measures, and outcomes at discharge. We also numerically compared the results from Sarawak with the published data from selected national and international cohorts.
RESULTS: We analysed 1435 ischaemic stroke cases. The mean age was 60.1±13.2 years old; 64.9% were male; median baseline National Institute of Health Stroke Scale was seven points. Hypertension was the most prevalent risk factor of ischaemic stroke; 12.7% had recurrent stroke; 13.7% were active smokers. The intravenous thrombolysis rate was 18.8%. We achieved 80-90% in three GWTG-Stroke performance measures and 90-98% in four additional quality measures in our ischaemic stroke management. At discharge, 57% had modified Rankin Scale of 0-2; 6.7% died during hospitalisation. When compared with selected national and international data, patients in Sarawak were the youngest; Sarawak had more male and more first-ever stroke. Thrombolysis rate in Sarawak was higher compared with most studies in the comparison. Functional outcome at discharge in Sarawak was better than national cohort but still lagging behind when compared with the developed countries. In-hospital mortality rate in Sarawak was slightly lower than the national data but higher when compared with other countries.
CONCLUSION: Our study described characteristics, management, and outcomes of ischaemic stroke in Sarawak. We achieved high compliance with most of GTWG-Stroke performance and quality indicators. Sarawak had better outcomes than the national results on ischaemic stroke. However, there is still room for improvement when compared with other countries. Actions are needed to reduce the cardiovascular burdens for stroke prevention, enhance healthcare resources for stroke care, and improve intravenous thrombolysis treatment in Sarawak.
METHODS: From the Malaysian National Neurology Registry, we included hypertensive patients with first ischemic stroke who presented within 48 hours from ictus. Antihypertensive drugs were divided into Ang II increasers (angiotensin-I receptor blockers (ARBs), calcium channel blockers (CCBs) and diuretics) and Ang II suppressors (angiotensin-converting-enzyme inhibitors (ACEIs) and beta blockers). We evaluated stroke severity during admission with the National Institute of Health Stroke Scale (NIHSS). We performed a multivariable logistic regression with the score being dichotomized at 15. Scores of less than 15 were categorized as less severe stroke.
RESULTS: A total of 710 patients were included. ACEIs was the most commonly prescribed antihypertensive drug in patients using Ang II suppressors (74%) and CCBs, in patients prescribed with Ang II increasers at 77%. There was no significant difference in the severity of ischemic stroke between patients who were using Ang II increasers in comparison to patients with Ang II suppressors (OR: 1.32, 95%CI: 0.83-2.10, p = 0.24).
CONCLUSION: In our study, we found that use of antihypertensive drugs that increase Ang II formation was not associated with less severe ischemic stroke as compared to use of antihypertensive drugs that suppress Ang II formation.