Platform Presentation The Joint Annual Meeting of the Stroke Society of Australasia (SSA) and Smartstrokes 2023

Developing Miniaturised Carbon Nanotube Brain Scanners for Standard Road and World-First Air Ambulances (#25)

Thomas McSkimming 1 2 3 , Anna H Balabanski 4 5 , Angela Dos Santos 4 , Anthony Skeats 3 , Francesca Langenberg 4 , Andrew Bivard 4 , Brian Gonzales 6 , Chris Delnooz 3 , Peter Cooper 3 , Damien Easton 4 , Wojtek Zbijewski 1 , Alejandro Sisniega 1 , Alejandro Lopez Montez 1 , Egon Perilli 7 , Karen Reynolds 7 , Geoffrey A Donnan 4 , Stephen M Davis 4
  1. Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
  2. Department of Biomedical Engineering, Flinders University, Adelaide, South Australia, Australia
  3. Micro-X Engineering, Adelaide, South Australia, Australia
  4. Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
  5. Department of Neuroscience, The Central Clinical School, Monash University and Alfred Health, Melbourne, Victoria, Australia
  6. Micro-X Engineering, Seattle, Washington State, United States of America
  7. Medical Device Research Institute, Flinders University, Adelaide, South Australia, Australia

Background: Mobile Stroke Units have been shown to improve stroke outcomes by bringing neuroimaging to the patient, reducing time-to-treatment. However, associated costs limit their use to densely populated metropolitan areas, further widening the gap between rural and urban stroke outcomes. The Australian Stroke Alliance, a national collaboration aiming to reshape prehospital stroke care, has partnered with Micro-X Ltd to develop a lightweight, portable, and affordable brain scanner. The scanner, based on a compact arrangement of 31 carbon nanotube x-ray sources and a curved x-ray detector, will weigh less than 100kg (Neurologica CereTomTM weighs approximately 500kg) and be sufficiently compact to be installed in standard road and world-first air ambulances.

Aims:  We aim to determine if this novel brain scanner will sensitively detect simulated small-volume intracerebral haemorrhage.

Methods: Scanner geometry, including source radius, detector radius, angular span, and rotational indexing, were optimised using high-fidelity simulations and validated using an eight degrees-of-freedom x-ray test bench. Initial artifact correction included truncation correction by modification of statistical weights in reconstruction, and scatter correction using Monte-Carlo simulation.

Results: Contrast-to-noise ratio and uniformity were maximized when source and detector radius were approximately equal, and angular span was maximized. The inclusion of a 45° rotational indexing minimized artifacts from limited-angular range. Truncation artifacts were greatly reduced using statistical weight modification, and initial scatter correction significantly reduced the cupping artifact, resulting in improved simulated ICH detection. Simulated intracerebral haemorrhage of 115 Hounsfield units contrast, and 33.5mm3 were detected in physical phantom scans.

Conclusion: We demonstrate feasibility of a compact, lightweight multisource computed tomography for stroke assessment. Ongoing algorithmic improvement, including artifact correction, is expected to detect intracerebral haemorrhage reliably. These scanners would facilitate mobile stroke imaging and reperfusion therapy in rural and remote areas, improving equity in acute stroke treatment.