Magnetic barcode imaging for contrast agents

Purpose To demonstrate a new MR imaging approach that unambiguously identifies and quantitates contrast agents based on intrinsic agent properties such as r 1 , r 2 , , and magnetic susceptibility. The approach is referred to as magnetic barcode imaging (MBI). Methods Targeted and bioresponsive contrast agents were imaged in agarose phantoms to generate T 1 , T 2 , , and quantitative susceptibility maps. The parameter maps were processed by a machine learning algorithm that is trained to recognize the contrast agents based on these parameters. The output is a quantitative map of contrast agent concentration, identity, and functional state. Results MBI allowed the quantitative interpretation of intensities, removed confounding backgrounds, enabled contrast agent multiplexing, and unambiguously detected the activation and binding states of bioresponsive and targeted contrast agents. Conclusion MBI has the potential to overcome significant limitations in the interpretation, quantitation, and multiplexing of contrast enhancement by MR imaging probes. Magn Reson Med 77:970–978, 2017.