Session Report – Stroke Imaging 2025

This session on novel concepts and decision-making based on state-of-the-art imaging provided a powerful start to ESOC 2025. The presentations highlighted the evolving role of advanced imaging in acute stroke management, combining scientific insight with practical application.

Professor Bijoy Menon – University of Calgary, Canada

Professor Menon opened the session with a compelling talk on CT hypodensities and their implications for decision-making in intravenous thrombolysis (IVT) and thrombectomy. He explained the pathophysiological basis: as tissue water content increases during ischemia, Hounsfield units drop, manifesting as hypodensity on CT. He outlined two key concepts:

• Extent of ischemia (assessed via ASPECTS)
• Degree of hypodensity (quantified density reduction)

Although both markers correlate with poor outcomes and higher rates of symptomatic intracranial hemorrhage, there is no strong evidence that these imaging features modify the efficacy of IVT. Therefore, patients with limited ischemic changes should always be treated. For those with more extensive damage, he advised caution and careful monitoring, but emphasised that these patients should not be automatically excluded from reperfusion therapies.

Petra Cimflova – Stroke Research Center, Bern, Switzerland

Ms. Cimflova introduced post-thrombectomy flat-panel CT as a novel tool available directly in the angiosuite. The latest systems allow acquisition not only of native CT images but also of perfusion scans. One highlight was the DOT (Distal Occlusion Tracker) sign, which indicates residual contrast in a blocked distal vessel and is highly specific for incomplete reperfusion – if  you see a DOT sign, it’s not TICI 3.

She also discussed early detection of complications such as subarachnoid or intracerebral hemorrhage, which can be identified immediately post-procedure. While subtle subarachnoid hemorrhage is common, only higher grades of bleeding have a meaningful impact on outcomes.

Perfusion imaging in this context is particularly helpful in assessing tissue viability and eloquence, guiding decisions on whether to pursue further reperfusion (e.g., intra-arterial thrombolytics or additional distal passes).

Professor Kevin Sheth – Yale School of Medicine, USA

Professor Sheth presented recent advances in low-field, portable MRI systems. He emphasised their transformative potential: while standard MRI is costly and often inaccessible, these new devices are more affordable, mobile, and require less maintenance. This could revolutionise stroke care, particularly in prehospital settings, hyperacute care environments, and critically ill patients across various disciplines.

Though current image quality does not yet match that of conventional MRI, ongoing developments in hardware, software, and AI-driven enhancement suggest substantial improvements are on the horizon. While still primarily used in research, these devices are moving steadily toward broader clinical application.

Professors Stephen Davis & Geoffrey Donnan – Parkville, Australia

In a joint presentation, Professors Davis and Donnan explored ultralightweight brain imaging technologies – critical for stroke care in geographically remote settings. They showcased nanotube-based CT scanners (approx. 70 kg) and low-field MRI devices (approx. 15 kg), both designed for deployment in ambulances, helicopters, aircraft, and even by first responders.

Although not yet commercially available or licensed, these technologies promise to dramatically reduce time to treatment. Clinical trials and feasibility studies are eagerly awaited to validate their effectiveness and real-world utility.

Anke Wouters – Leuven, Belgium

Dr. Wouters concluded the session with a presentation on penumbra imaging in patients with large established infarct cores. She reported that patients without a perfusion mismatch generally did not benefit from thrombectomy, but noted that the sample size in this group was small, leaving room for uncertainty.

She emphasised that moving beyond the traditional core–penumbra dichotomy by incorporating quantitative analysis of hypoattenuation and perfusion allows for more nuanced and individualised treatment decisions.

This dynamic session illustrated the critical role of advanced imaging in guiding stroke treatment and underscored the need for continued innovation, validation, and integration into clinical workflows.