title: Magnetic barcode imaging for contrast agents.
abstract: To demonstrate a new MR imaging approach that unambiguously identifies and quantitates contrast agents based on intrinsic agent properties such as r1, r2, r2*, and magnetic susceptibility. The approach is referred to as magnetic barcode imaging (MBI).
  
  
  
  Targeted and bioresponsive contrast agents were imaged in agarose phantoms to generate T1, T2, T2*, 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.
  
  
  
  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.
  
  
  
  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. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois, USA.
authors.forename: Andy H
authors.initials: AH
authors.lastname: Hung
authors.affiliation: Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois, USA.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Lilley
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, China.
authors.forename: Fengqin
authors.initials: F
authors.lastname: Hu
authors.affiliation: Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois, USA.
authors.forename: Victoria S R
authors.initials: VS
authors.lastname: Harrison
authors.affiliation: Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, Evanston, Illinois, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Meade
mesh_terms: D000465:Algorithms; D003287:Contrast Media / Q000032:analysis* / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D057054:Molecular Imaging / Q000379:methods*; D015336:Molecular Probe Techniques; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media
keywords: contrast agent; machine learning; magnetic resonance imaging; molecular imaging