Application of transcranial Doppler in cerebrovascular diseases

Analyzing post-endovascular treatment stroke prognosis with transcranial Doppler and quantitative electroencephalography

OBJECTIVE

Despite successful recanalization following acute ischemic stroke, patients may have a poor prognosis. We investigated whether transcranial Doppler combined with quantitative electroencephalography can identify patients with a poor prognosis at an early stage.

METHODS

Prospectively recruited patients with successful recanalization after endovascular treatment for acute ischemic stroke were assessed for prognosis at 90 days using the modified Rankin Scale. Clinical information and National Institute of Health Stroke Scale scores were recorded. Transcranial Doppler combined with quantitative electroencephalography was used to evaluate brain function.

RESULTS

Of the 37 patients (63.5 ± 11.7 years) studied, 18 had a poor prognosis at 90 days (modified Rankin Scale >3). Multivariable analysis revealed that transcranial Doppler indicators of the pulsatility index of the unaffected side, quantitative electroencephalography indicators of the pairwise-derived Brain Symmetry Index, and National Institute of Health Stroke Scale score were independent prognostic indicators. Modeling indicated that combining these independent predictors yielded superior accuracy and net clinical benefit to any single variable. With the final predictive model presented as a nomogram, internal validation by bootstrap resampling showed good discrimination with a concordance index of 0.961. The calibration curve displayed good agreement of predicted and actual probabilities.

INTERPRETATION

The nomogram prediction model combining transcranial Doppler with quantitative electroencephalography and National Institute of Health Stroke Scale scores can provide guidance for individualized risk prediction in patients with acute ischemic stroke after revascularization.

Empowering sickle cell disease care: the rise of TechnoRehabLab in Sub-Saharan Africa for enhanced patient's perspectives

Sickle-cell Disease (SCD) is a major public health problem in Africa, and there are significant obstacles to its comprehensive management, particularly in terms of access to appropriate healthcare. This calls for inventive approaches to improve patients' prospects. Among the major challenges to be met are the primary and secondary prevention of certain serious complications associated with the disease, such as neurocognitive, motor and respiratory functional disorders. This perspective argues for the rapid creation of specific, cost-effective, technology-supported rehabilitation centres to advance SCD care, identify patients at high risk of stroke and implement tailored rehabilitation strategies. The TechnoRehabLab in Lubumbashi illustrates this shift in thinking by using cutting-edge technologies such as virtual reality (VR), serious games and mobile health to create a comprehensive and easily accessible rehabilitation framework. Diagnostic tools used to perform functional assessment can be used to identify cognitive, balance and walking deficits respectively. Transcranial Doppler enables early detection of sickle cell cerebral vasculopathy, making it possible to provide early and appropriate treatment. VR technology and serious games enable effective rehabilitation and cognitive stimulation, which is particularly advantageous for remote or community-based rehabilitation. In the context of African countries where there is a glaring disparity in access to digital resources, the TechnoRehabLab serves as a tangible example, demonstrating the flexibility and accessibility of technology-assisted rehabilitation. This perspective is an urgent call to governments, non-governmental organisations and the international community to allocate resources to the replication and expansion of similar facilities across Africa.

High-resolution magnetic resonance vessel wall imaging provides new insights into Moyamoya disease

Moyamoya disease (MMD) is a rare condition that affects the blood vessels of the central nervous system. This cerebrovascular disease is characterized by progressive narrowing and blockage of the internal carotid, middle cerebral, and anterior cerebral arteries, which results in the formation of a compensatory fragile vascular network. Currently, digital subtraction angiography (DSA) is considered the gold standard in diagnosing MMD. However, this diagnostic technique is invasive and may not be suitable for all patients. Hence, non-invasive imaging methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are often used. However, these methods may have less reliable diagnostic results. Therefore, High-Resolution Magnetic Resonance Vessel Wall Imaging (HR-VWI) has emerged as the most accurate method for observing and analyzing arterial wall structure. It enhances the resolution of arterial walls and enables quantitative and qualitative analysis of plaque, facilitating the identification of atherosclerotic lesions, vascular entrapment, myofibrillar dysplasia, moyamoya vasculopathy, and other related conditions. Consequently, HR-VWI provides a new and more reliable evaluation criterion for diagnosing vascular lesions in patients with Moyamoya disease.

Intraoperative monitoring of the central and peripheral nervous systems: a narrative review

The central and peripheral nervous systems are the primary target organs during anaesthesia. At the time of the inception of the British Journal of Anaesthesia, monitoring of the central nervous system comprised clinical observation, which provided only limited information. During the 100 yr since then, and particularly in the past few decades, significant progress has been made, providing anaesthetists with tools to obtain real-time assessments of cerebral neurophysiology during surgical procedures. In this narrative review article, we discuss the rationale and uses of electroencephalography, evoked potentials, near-infrared spectroscopy, and transcranial Doppler ultrasonography for intraoperative monitoring of the central and peripheral nervous systems.

Comparable dynamic cerebral autoregulation and neurovascular coupling of the posterior cerebral artery between healthy men and women

AIMS

Most studies focus on dynamic cerebral autoregulation (dCA) in the middle cerebral artery (MCA), and few studies investigated neurovascular coupling (NVC) and dCA in the posterior cerebral artery (PCA). We investigated NVC and dCA of the PCA in healthy volunteers to identify sex differences.

METHODS

Thirty men and 30 age-matched women completed dCA and NCV assessments. The cerebral blood flow velocity (CBFV) and mean arterial pressure were evaluated using transcranial Doppler ultrasound and a servo-controlled plethysmograph, respectively. The dCA parameters were analyzed using transfer function analysis. The NCV was evaluated by eyes-open and eyes-closed (24 s each) periodically based on voice prompts. The eyes-open visual stimulation comprised silent reading of Beijing-related tourist information.

RESULTS

The PCA gain was lower than that of the MCA in all frequency ranges (all p < 0.05). Phase was consistent across the cerebrovascular territories. The cerebrovascular conductance index (CVCi) and mean CBFV (MV) of the PCA were significantly higher during the eyes-open than eyes-closed period (CVCi: 0.50 ± 0.12 vs. 0.38 ± 0.10; MV: 42.89 ± 8.49 vs. 32.98 ± 7.25, both p < 0.001). The PCA dCA and NVC were similar between the sexes.

CONCLUSION

We assessed two major mechanisms that maintain cerebral hemodynamic stability in healthy men and women. The visual stimulation-evoked CBFV of the PCA was significantly increased compared to that during rest, confirming the activation of NVC. Men and women have similar functions in PCA dCA and NCV.

Harnessing Passive Pulsatile Shear Stress for Alzheimer's Disease Prevention and Intervention

 Alzheimer's disease (AD) affects more than 40 million people worldwide and is the leading cause of dementia. This disease is a challenge for both patients and caregivers and puts a significant strain on the global healthcare system. To address this issue, the Lancet Commission recommends focusing on reducing modifiable lifestyle risk factors such as hypertension, diabetes, and physical inactivity. Passive pulsatile shear stress (PPSS) interventions, which use devices like whole-body periodic acceleration, periodic acceleration along the Z-axis (pGz), and the Jogging Device, have shown significant systemic and cellular effects in preclinical and clinical models which address these modifiable risks factors. Based on this, we propose that PPSS could be a potential non-pharmacological and non-invasive preventive or therapeutic strategy for AD. We perform a comprehensive review of the biological basis based on all publications of PPSS using these devices and demonstrate their effects on the various aspects of AD. We draw from this comprehensive analysis to support our hypothesis. We then delve into the possible application of PPSS as an innovative intervention. We discuss how PPSS holds promise in ameliorating hypertension and diabetes while mitigating physical inactivity, potentially offering a holistic approach to AD prevention and management.

The Role of High-Resolution Magnetic Resonance Imaging in Cerebrovascular Disease: A Narrative Review

High-resolution magnetic resonance imaging (HRMRI) is the most important and popular vessel wall imaging technique for the direct assessment of vessel wall and cerebral arterial disease. It can identify the cause of stroke in high-risk plaques and differentiate the diagnosis of head and carotid artery dissection, including inflammation, Moya Moya disease, cerebral aneurysm, vasospasm after subarachnoid hemorrhage, reversible cerebral vasoconstriction syndrome, blunt cerebrovascular injury, cerebral arteriovenous malformations, and other stenosis or occlusion conditions. Through noninvasive visualization of the vessel wall in vitro, quantified assessment of luminal stenosis and pathological features of the vessel wall can provide clinicians with further disease information. In this report, technical considerations of HRMRI are discussed, and current clinical applications of HRMRI are reviewed.