Magnetic Particle Imaging: In vitro Signal Analysis and Lumen Quantification of 21 Endovascular Stents

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Nanotechnology

Background:

• Endovascular stents are crucial for treating stenosed blood vessels.
• High rates of in-stent re-stenosis necessitate noninvasive imaging for early occlusion detection.
• Computed tomography (CT) and magnetic resonance imaging (MRI) are limited by material-induced artifacts for stent lumen evaluation.

Purpose of the Study:

• To investigate the potential of magnetic particle imaging (MPI) for visualizing and quantifying endovascular stent lumina.
• To assess MPI's ability to overcome limitations of CT and MRI in stent imaging.

Main Methods:

• In vitro study involving 21 endovascular stents implanted in vessel phantoms.
• Preclinical MPI scanner used for signal analysis and artifact evaluation.
• Phantoms scanned with and without tracer material; lumen diameter quantified using a calibrated threshold.

Main Results:

• MPI successfully visualized stent lumina across various stent types without material-induced artifacts.
• Stents generated insufficient signals in MPI, preventing artifact generation.
• Stent lumen quantification demonstrated a high correlation (r = 0.98) between calculated and nominal diameters.

Conclusions:

• MPI offers accurate visualization and quantification of endovascular stent lumina.
• MPI overcomes the artifact limitations inherent in CT and MRI for stent imaging.
• MPI shows promise as a noninvasive imaging modality for early detection of stent occlusion.