Background and purpose Currently, there is neither a standard protocol for vessel wall MR imaging of intracranial atherosclerotic disease (ICAD) nor a gold standard phantom to compare MR sequences. In this study, a plaque phantom is developed and characterized that provides a platform for establishing a uniform imaging approach for ICAD.
Materials and methods A patient specific injection mold was 3D printed to construct a geometrically accurate ICAD phantom. Polyvinyl alcohol hydrogel was infused into the core shell mold to form the stenotic artery. The ICAD phantom incorporated materials mimicking a stenotic vessel and plaque components, including fibrous cap and lipid core. Two phantoms were scanned using high resolution cone beam CT and compared with four different 3 T MRI systems across eight different sites over a period of 18 months. Inter-phantom variability was assessed by lumen dimensions and contrast to noise ratio (CNR).
Results Quantitative evaluation of the minimum lumen radius in the stenosis showed that the radius was on average 0.80 mm (95% CI 0.77 to 0.82 mm) in model 1 and 0.77 mm (95% CI 0.74 to 0.81 mm) in model 2. The highest CNRs were observed for comparisons between lipid and vessel wall. To evaluate manufacturing reproducibility, the CNR variability between the two models had an average absolute difference of 4.31 (95% CI 3.82 to 5.78). Variation in CNR between the images from the same scanner separated by 7 months was 2.5–6.2, showing reproducible phantom durability.
Conclusions A plaque phantom composed of a stenotic vessel wall and plaque components was successfully constructed for multicenter high resolution MRI standardization.
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Contributors J-YC, KVDM, MJG, TL, TRB, SA, TJC, ARC, RHS, EF, and TNT: designed the phantom and imaging experiments, performed the experiments, analyzed and processed the data, and drafted the manuscript. RMK and OWB: contributed to phantom modeling and MR characterization, and revised the draft manuscript. TL, TRB, SA, TJC, AKB, XJZ, HM, SZ, JWR, and RHS: acquired imaging data and revised the manuscript.
Funding This work was supported in part by NINDS 5R21-TW010356-02 (to TNT). The content is solely the responsibility of the authors and does not represent the official views of the NIH.
Competing interests MJG: consultant on a fee per hour basis for Codman Neurovascular, InNeuroCo Inc, and Stryker Neurovascular; holds stock in InNeuroCo; and research support from the National Institutes of Health (NIH), Cerevasc LLC, Codman Neurovascular, the Cure Tay Sachs Foundation, Gentuity LLC, InNeuroCo, Medtronic Neurovascular, Microvention/Terumo, Mivi Neuroscience, Neuravi, Neurogami, Neuronal Protection Systems, Rapid Medical, R92M LLC, Philips Healthcare, Stryker Neurovascular, and the Wyss Institute. SA: NIH 1R21HL130969. RHS: The Heart and Stroke Foundation of Canada New Investigator Award, the Canadian Partnership for Stroke Recovery, and the Department of Medicine at Sunnybrook and University of Toronto. TNT: NINDS 5R21-TW010356-02.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement: For access to the raw images obtained in this study, please contact the corresponding author.
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