Cerebral haemodynamics in symptomatic intracranial atherosclerotic disease: a narrative review of the assessment methods and clinical implications

Intracranial atherosclerotic disease (ICAD) is a common cause of ischaemic stroke and transient ischaemic attack (TIA) with a high recurrence rate. It is often referred to as intracranial atherosclerotic stenosis (ICAS), when the plaque has caused significant narrowing of the vessel lumen. The lesion is usually considered 'symptomatic ICAD/ICAS' (sICAD/sICAS) when it has caused an ischaemic stroke or TIA. The severity of luminal stenosis has long been established as a prognostic factor for stroke relapse in sICAS. Yet, accumulating studies have also reported the important roles of plaque vulnerability, cerebral haemodynamics, collateral circulation, cerebral autoregulation and other factors in altering the stroke risks across patients with sICAS. In this review article, we focus on cerebral haemodynamics in sICAS. We reviewed imaging modalities/methods in assessing cerebral haemodynamics, the haemodynamic metrics provided by these methods and application of these methods in research and clinical practice. More importantly, we reviewed the significance of these haemodynamic features in governing the risk of stroke recurrence in sICAS. We also discussed other clinical implications of these haemodynamic features in sICAS, such as the associations with collateral recruitment and evolution of the lesion under medical treatment, and indications for more individualised blood pressure management for secondary stroke prevention. We then put forward some knowledge gaps and future directions on these topics.

Additive Manufacturing of Thermoelectric Microdevices for 4D Thermometry

Thermometry, the process of measuring temperature, is one of the most fundamental tasks not only for understanding the thermodynamics of basic physical, chemical, and biological processes but also for thermal management of microelectronics. However, it is a challenge to acquire microscale temperature fields in both space and time. Here, a 3D printed micro-thermoelectric device that enables direct 4D (3D Space + Time) thermometry at the microscale is reported. The device is composed of freestanding thermocouple probe networks, fabricated by bi-metal 3D printing with an outstanding spatial resolution of a few µm. It shows that the developed 4D thermometry can explore dynamics of Joule heating or evaporative cooling on microscale subjects of interest such as a microelectrode or a water meniscus. The utilization of 3D printing further opens up the possibility to freely realize a wide range of on-chip, freestanding microsensors or microelectronic devices without the design restrictions by manufacturing processes.

Protocol for a mixed-methods randomised controlled trial evaluating the effectiveness of a dyadic expressive arts-based intervention in improving the psychosocial well-being of children with intellectual disability in special schools and their mothers

INTRODUCTION

Mothers of children with intellectual disability (ID) are often distressed because of intensive workloads and difficulties in communicating with their children. Given the interdependence between the psychosocial well-being of such dyads, interventions that promote parent-child relationships and mutual communication would be beneficial. Arts provide alternative avenues for expression and offer an imaginative and playful environment for discovering new communication strategies. Given the lack of studies on arts-based dyadic interventions, this study aims to examine the effectiveness of dyadic expressive arts-based intervention (EXAT) in improving the psychosocial outcomes of children with ID and their mothers and the mother-child relationships.

METHODS AND ANALYSIS

This study will adopt a mixed-methods randomised controlled trial design, wherein 154 dyads of children with ID and their mothers will be randomised into either the dyadic EXAT group or the treatment-as-usual waitlist control group. Quantitative data will be collected at four time points: baseline (T0), postintervention (T1), 3-month postintervention (T2) and 6-month postintervention (T3). Qualitative data will be collected from a subset of 30 mothers in the intervention group at T1 and T3 to document their experiences and perceived changes after the intervention. Mixed-effects models and path analysis will be adopted to analyse the quantitative data, whereas thematic analysis will be applied to the qualitative data. Both sets of data will be triangulated for an integrated view of the effectiveness and mechanism of the intervention.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Human Research Ethics Committee of the University of Hong Kong (Ref. no.: EA200329). Written consent forms will be obtained from all recruited participants (mothers, children with ID and teachers/social workers) before data collection. The study findings will be disseminated in international conferences and peer-reviewed academic journals.

TRIAL REGISTRATION NUMBER

NCT05214859.

Plaque morphology in acute symptomatic intracranial atherosclerotic disease

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is globally a major ischaemic stroke subtype with high recurrence. Understanding the morphology of symptomatic ICAD plaques, largely unknown by far, may help identify vulnerable lesions prone to relapse.

METHODS

We prospectively recruited patients with acute ischaemic stroke or transient ischaemic attack attributed to high-grade ICAD (60%-99% stenosis). Plaque morphological parameters were assessed in three-dimensional rotational angiography, including surface contour, luminal stenosis, plaque length/thickness, upstream shoulder angulation, axial/longitudinal plaque distribution and presence of adjoining branch atheromatous disease (BAD). We compared morphological features of smooth, irregular and ulcerative plaques and correlated them with cerebral ischaemic lesion load downstream in MRI.

RESULTS

Among 180 recruited patients (median age=60 years; 63.3% male; median stenosis=75%), plaque contour was smooth (51 (28.3%)), irregular (101 (56.1%)) or ulcerative (28 (15.6%)). Surface ulcers were mostly at proximal (46.4%) and middle one-third (35.7%) of the lesions. Most (84.4%) plaques were eccentric, and half had their maximum thickness over the distal end. Ulcerative lesions were thicker (medians 1.6 vs 1.3 mm; p=0.003), had steeper upstream shoulder angulation (56.2° vs 31.0°; p<0.001) and more adjoining BAD (83.3% vs 57.0%; p=0.033) than non-ulcerative plaques. Ulcerative plaques were significantly associated with coexisting acute and chronic infarcts downstream (35.7% vs 12.5%; adjusted OR 4.29, 95% CI 1.65 to 11.14, p=0.003). Sensitivity analyses in patients with anterior-circulation ICAD lesions showed similar results in the associations between the plaque types and infarct load.

CONCLUSIONS

Ulcerative intracranial atherosclerotic plaques were associated with vulnerable morphological features and had a higher cumulative infarct load downstream.