Inter-user Comparison for Quantification of Superparamagnetic Iron Oxides with Magnetic Particle Imaging Across Two Institutions Highlights a Need for Standardized Approaches

Hayden J Good; Olivia C Sehl; Julia J Gevaert; Bo Yu; Maryam A Berih; Sebastian A Montero; Carlos M Rinaldi-Ramos; Paula J Foster

doi:10.1007/s11307-023-01829-2

Inter-user Comparison for Quantification of Superparamagnetic Iron Oxides with Magnetic Particle Imaging Across Two Institutions Highlights a Need for Standardized Approaches

Mol Imaging Biol. 2023 Oct;25(5):954-967. doi: 10.1007/s11307-023-01829-2. Epub 2023 Jun 29.

Authors

Hayden J Good¹, Olivia C Sehl², Julia J Gevaert², Bo Yu³, Maryam A Berih², Sebastian A Montero³, Carlos M Rinaldi-Ramos^{3

4}, Paula J Foster²

Affiliations

¹ Department of Chemical Engineering, University of Florida, 1006 Center Dr. P.O. Box 116005, Gainesville, FL, 32611, USA. Haydengood34@ufl.edu.
² Department of Medical Biophysics, Imaging Research Laboratories, Western University, Robarts Research Institute, London, ON, N6A 5B7, Canada.
³ Department of Chemical Engineering, University of Florida, 1006 Center Dr. P.O. Box 116005, Gainesville, FL, 32611, USA.
⁴ J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr. JG56, P.O. Box 116131, Gainesville, FL, 32611, USA.

PMID: 37386319
DOI: 10.1007/s11307-023-01829-2

Abstract

Purpose: Magnetic particle imaging (MPI) is being explored in biological contexts that require accurate and reproducible quantification of superparamagnetic iron oxide nanoparticles (SPIONs). While many groups have focused on improving imager and SPION design to improve resolution and sensitivity, a few have focused on improving quantification and reproducibility of MPI. The aim of this study was to compare MPI quantification results by two different systems and the accuracy of SPION quantification performed by multiple users at two institutions.

Procedures: Six users (3 from each institute) imaged a known amount of Vivotrax + (10 μg Fe), diluted in a small (10 μL) or large (500 μL) volume. These samples were imaged with or without calibration standards in the field of view, to create a total of 72 images (6 users × triplicate samples × 2 sample volumes × 2 calibration methods). These images were analyzed by the respective user with two region of interest (ROI) selection methods. Image intensities, Vivotrax + quantification, and ROI selection were compared across users, within and across institutions.

Results: MPI imagers at two different institutes produce significantly different signal intensities, that differ by over 3 times for the same concentration of Vivotrax + . Overall quantification yielded measurements that were within [Formula: see text] 20% from ground truth; however, SPION quantification values obtained at each laboratory were significantly different. Results suggest that the use of different imagers had a stronger influence on SPION quantification compared to differences arising from user error. Lastly, calibration conducted from samples in the imaging field of view gave the same quantification results as separately imaged samples.

Conclusions: This study highlights that there are many factors that contribute to the accuracy and reproducibility of MPI quantification, including variation between MPI imagers and users, despite pre-defined experimental setup, image acquisition parameters, and ROI selection analysis.

Keywords: Inter-user; MPI; Magnetic particle imaging; Quantification; Reproducibility; SPIONs; Superparamagnetic iron oxide nanoparticles; Vivotrax +.

Abstract

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