In vivo Multimodal Magnetic Particle Imaging for Early Detection of Ischemic Stroke in Tree Shrews

Ischemic stroke is a significant threat to human life and health, and timely diagnosis is essential for improving patient outcomes. Magnetic Particle Imaging (MPI), as an emerging high-sensitivity imaging technology, holds significant potential for the diagnosis of ischemic stroke. It is necessary to conduct multimodal MPI research based on the characteristics of the animal model and the detection needs of ischemic stroke.

We used tree shrews, which have a close phylogenetic relationship with primates, as experimental subjects and established a photothrombotic (PT) stroke model. Considering the body size of tree shrews and the high-sensitivity detection requirements for ischemic stroke, a dedicated MPI receiving system for tree shrews was developed based on the primate brain MPI equipment. After validating the MPI system's performance, multimodal MPI fusion imaging of the tree shrew brain was performed by combining magnetic resonance imaging (MRI) and computed tomography (CT).

The sensitivity of the receiving system for tree shrews is 0.017 mg Fe/mL, which is 8 times higher than that of the original system. Within one hour after the establishment of the PT stroke model, the MPI signal intensity in ischemic stroke tree shrews was approximately 25% lower than in the control group, while MRI showed no significant differences. On the 6th and 12th days after ischemic stroke onset, MRI images revealed clear lesion locations. Anatomical results of the tree shrew brain revealed significant lesions, confirming the successful establishment of the PT stroke model.

The dedicated MPI receiving system developed in this study significantly enhanced MPI sensitivity. The multimodal MPI imaging platform integrates the advantages of MRI and CT structural imaging based on high-sensitivity detection, enabling early detection of ischemic stroke in tree shrews.