High-sensitivity in vivo contrast for ultra-low field magnetic resonance imaging using superparamagnetic iron oxide nanoparticles

Abstract

Magnetic resonance imaging (MRI) scanners operating at ultra-low magnetic fields (ULF; <10 mT) are uniquely positioned to reduce the cost and expand the clinical accessibility of MRI. A fundamental challenge for ULF MRI is obtaining high-contrast images without compromising acquisition sensitivity to the point that scan times become clinically unacceptable. Here, we demonstrate that the high magnetization of superparamagnetic iron oxide nanoparticles (SPIONs) at ULF makes possible relaxivity- and susceptibility-based effects unachievable with conventional contrast agents (CAs). We leverage these effects to acquire high-contrast images of SPIONs in a rat model with ULF MRI using short scan times. This work overcomes a key limitation of ULF MRI by enabling in vivo imaging of biocompatible CAs. These results open a new clinical translation pathway for ULF MRI and have broader implications for disease detection with low-field portable MRI scanners.

Signal-enhanced real-time magnetic resonance of enzymatic reactions at millitesla fields

“…This includes affordable low field magnetic resonance imaging (MRI) devices. 55 Lastly, we foresee that analytical possibilities will be unlocked for ZULF-NMR in the future. This can be achieved by combining the presented method with highly sensitive detection schemes that include the EHQE (external-high-quality-enhanced) NMR approach for Faraday detection 56 or the use of SQUIDs, atomic magnetometers and NV diamond magnetometers with the potential to measure real-time kinetics of metabolites in single cells.…”

Therapeutic Applications of Functional Nanomaterials for Prostatitis

“…Currently, many nanomaterials have been successfully developed as contrast agents for clinical use ( Lu et al, 2017 ; Hu et al, 2018 ; Song et al, 2018 ). For example, iron oxide nanoparticles and manganese oxide nanoparticles are used as MRI contrast agents because of their unique magnetic properties ( Waddington et al, 2020 ). Gold nanorods have been used in photoacoustic imaging (PAI) due to their unique surface plasmon resonance properties ( Huang et al, 2019 ).…”

Boosting the signal-to-noise of low-field MRI with deep learning image reconstruction

“…MRI scanners that operate in the low magnetic field regime (i.e., < 0.3 T) as a rule suffer from reduced image quality that arises from the low Boltzmann polarization at these field strengths resulting in weak NMR signals 1 . Accordingly, images obtained at low-field suffer from low signal-to-noise ratio (SNR) which can be mitigated in part by increased acquisition times 2 .…”