Open structure magnetic particle imaging by nonlinear back projection tomography reconstruction

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Physics

Background:

• Open structure magnetic particle imaging (MPI) systems face challenges with nonlinear field free line (FFL) variations.
• These variations cause significant distortion in x-space image reconstruction, particularly in large regions of interest.

Purpose of the Study:

• To develop a nonlinear FFL projection reconstruction algorithm.
• To mitigate edge distortion issues in open structure MPI imaging.

Main Methods:

• Calculating the curvature change law of FFLs during scanning.
• Designing a nonlinear back projection algorithm based on observed FFL nonlinearities.
• Applying the algorithm for blood vessel tomography.

Main Results:

• The proposed nonlinear back projection algorithm successfully reconstructs vascular faults in open structure MPI.
• It significantly suppresses image edge distortion and enhances positioning accuracy.
• The effective region of interest with low distortion increased 16-fold, with minimal gradient degradation.

Conclusions:

• A nonlinear inverse projection reconstruction algorithm effectively reduces structural artifacts from FFL distortion.
• This provides a viable reconstruction strategy for high-resolution imaging over large regions in open structure FFL-MPI.