Supplementary Material for: Marine Mobile Stroke Unit: A Pilot Study on the Feasibility and Quality of Brain Imaging

BACKGROUND: Timely early reperfusion therapies improve stroke outcomes, but geographic barriers often limit patient access to these essential treatments. Innovative care models emerged as potential solutions to overcome these accessibility constraints. We introduce a new paradigm in stroke care: the marine Mobile Stroke Units (MSUs).

METHODS: This is a prospective study to evaluate the feasibility, image quality, and inter-rater reliability of images produced by portable brain CT scanner on a catamaran while exposed to winds, waves and tides. We performed non-contrast brain portable CT scanning in healthy volunteers hourly while the catamaran was docked on the river over 7 consecutive days. Six raters (3 neurologists, 3 radiologists) evaluated brain imaging. Twenty-three anatomical regions were assessed and categorized as ganglionic, supra-ganglionic, and posterior fossa. A quality imaging score ranges from 0 (lowest quality) to 5 (highest quality), with scores of 4 or 5 considered adequate image quality. We used Gwet's AC1 to assess Inter-rater agreement. Radiation dose, safety data and axis rotation data from catamaran were also collected.
RESULTS: Of the 168 recruited participants, all completed the study. There were 3,864 anatomical locations included in the analysis. Adequate image quality was demonstrated in 94.9%, 93.0% and 45.7% of anatomical items at the ganglionic, supra-ganglionic and posterior fossa regions. Interrater agreement was substantial at the ganglionic level (Gwet’s AC1 0.62, 95% CI: 0.54-0.70) and the supra-ganglionic level (Gwet’s AC1 0.80, 95% CI: 0.74-0.85). The agreement at the posterior fossa level was fair (Gwet's AC1 0.21, 95% CI: 0.13-0.29). No major adverse events occurred throughout the duration of the study.

CONCLUSIONS: Our study shows the feasibility and safety of a portable brain CT on a catamaran under real-world marine conditions. Our findings pave the way for testing the role of marine Mobile Stroke Unit for acute stroke management.