Multi-Patch Sequences in Magnetic Particle Imaging

In this project we develop multi-patch imaging sequences and reconstruction algorithms for enlarged measuring fields in magnetic particle imaging (MPI). The regular field-of-view (FOV) in MPI is limited due to physiological constraints such as tissue heating and nerve stimulation. In practice typical FOV are in the range of 2x2x1 cm³. In order to scan larger regions it is possible to shift the FOV to different positions and scan various smaller FOV, which can later be combined to a joint 3D dataset. Especially the reconstruction of multi-patch data is a computationally intensive and memory demanding task. In this project we develop algorithms for efficient reconstruction of multi-patch MPI data.

To reduce calibration time and speed up image reconstruction, we have introduced a number of different methods, including reducing the number of system matricessystem matrix warping, and overscan extrapolation.

Sketch of a multi-patch imaging sequence.

Project Publications

[191956]
Title: GPU Accelerated Multi-Patch Reconstruction.
Written by: N. Hackelberg, M. Boberg, and T. Knopp
in: <em>International Journal on Magnetic Particle Imaging</em>. (2025).
Volume: <strong>11</strong>. Number: (1 Suppl 1),
on pages: 1-2
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: https://doi.org/10.18416/IJMPI.2025.2503048
URL: https://www.journal.iwmpi.org/index.php/iwmpi/article/view/816
ARXIVID:
PMID:

[www]

Note: inproceedings, reconstruction, multi-patch

Abstract: The multi-patch approach in magnetic particle imaging is used to capture large field of views. System-matrix-based image reconstruction for this approach often considers a joint system of equations to minimize artifacts. Due to the prohibitive size of this inverse problem, reconstructions rely on iterative algorithms that do not need to keep the entire system matrix in memory. This work shows a graphical processing unit accelerated implementation of a generalized multi-patch operator. The achieved runtime improvements allow for multi-patch reconstructions using different optimization algorithms, which in turn allow for a flexible choice of regularization terms.