In vitro detection of gastrointestinal bleeding using single- and multi-contrast MPI

Gastrointestinal (GI) bleeding is a potentially life-threatening condition that is typically diagnosed using radiation-based imaging modalities such as computed tomography (CT) or catheter-based angiography. Magnetic Particle Imaging (MPI) could provide non-invasive, real-time volumetric imaging without ionizing radiation in future human-sized scanners that covers the entire GI tract. We have developed a human-sized (3D printed) phantom that represents both the bowel lumen and the vascular compartment of the bowel wall. One version has a perforation between the two compartments and a control phantom does not. For single contrast MPI, we evaluate the fluid exchange between the two lumen by observing an administered blood pool tracer. For multi-contrast MPI, the intestinal lumen was filled with an intestinal tracer, which represents an orally administered tracer, to allow co-registration of both tracers at the same location. Both single-and multi-contrast MPI are feasible to visualize GI bleeding and MPI may prove to be a useful tool for radiation-free detection of bleeding throughout the GI tract.