iMPI - Interventional Magnetic Particle Imaging

• Applicant: Dr. Patrick Vogel
• Subject Area: Medical Physics, Biomedical Technology ; Biophysics
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 410898690

For the treatment of cardiovascular diseases to date X-ray-guided, catheter-based, minimal-invasive interventions are state of the art. X-ray provide high spatial and temporal resolution but comes with the drawback of potentially high ionization radiation dosage, which can risk late cancer. Since interventions can be time-consuming they can result in significant radiation exposure for clinical staff working in a catheterization lab. A further limitation of X-ray fluoroscopy is the need for nephrotoxic and potentially allergenic iodine-based constrast agents.As radiation-free imaging technique with near real-time qualities Magnetic Resonance Imaging (MRI) has emerged. However, the workflow for MR-guided interventions is greatly hampered by issues such as the complex operation of an MRI, limited access to and communication with the patient, high acoustic noise levels and MRI safety regulations throughout the procedure. As a result, MRI has not been widely accepted for guiding interventions so far.As a new tracer-based, background-free imaging modality, Magnetic Particle Imaging (MPI) could be an intersting alternative. Since the first publication in 2005 several impressive leaps forward in development have been presented demonstrating the great potential of this young technologie for directly visualizing vessel structures without signal disturbances from background tissue. MPI is based on the non-linear response of superparamagnetic iron-oxide nanoparticles (SPIONs) in time and space dependent magnetic fields. The spatial distribution of the SPIONs is visualized by scanning the field of view with a so-called field-free point (FFP) or field-free line (FFL), which locally generates a strong magnetic field gradient. Several different approaches and scanner designs have been presented providing high sensitivity in the range of micro molar, sub-millimeter resolution, and high temporal resolution sufficient for real-time applications.The aim of this project is to develop and establish interventional Magnetic Particle Imaging (iMPI) as an alternative endovascular strategy for treatment of stenotic or occluded vessels in cardiovascular diseases in specific percutaneous transluminal balloon angioplasty (PTA).For that a novel concept is proposed for a near human sized MPI scanner tailored to the needs of modern cardiovascular imaging. To meet the requirements of a clinical environment a new open bore concept based on the TWMPI approach is applied and scanner properties are customized to feature fast and dynamic imaging of vasculature structures. To track and visualize required interventional instruments such a balloon catheters and guidewires MPI-visible materials are used. For seamless interventions, new protocols have to be evolved to optimize the whole process for MPI-guided PTA.The advantages for the patient and the medical staff are not only the absence of harmful radiation in an MPI-guided PTA but also the more comfortable access to the patient.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Volker Christian Behr; Professor Dr. Thorsten Bley