title: Improved dynamic response assessment for intra-articular injected iron oxide nanoparticles.
abstract: The emerging importance of nanoparticle technology, including iron oxide nanoparticles for monitoring development, progression, and treatment of inflammatory diseases such as arthritis, drives development of imaging techniques. Studies require an imaging protocol that is sensitive and quantifiable for the detection of iron oxide over a wide range of concentrations. Conventional signal loss measurements of iron oxide nanoparticle containing tissues saturate at medium concentrations and show a nonlinear/nonproportional intensity to concentration profile due to the competing effects of T₁ and T₂ relaxation. A concentration calibration phantom and an in vivo study of intra-articular injection in a rat knee of known concentrations of iron oxide were assessed using the difference-ultrashort echo time sequence giving a positive, quantifiable, unambiguous iron signal and monotonic, increasing concentration response over a wide concentration range in the phantom with limited susceptibility artifacts and high contrast in vivo to all other tissues. This improved dynamic response to concentration opens possibilities for quantification due to its linear nature at physiologically relevant concentrations.
authors.affiliation: Division of Radiology, Geneva University Hospitals, University of Geneva, Faculty of Medicine, Foundation for Medical Researchers, Geneva, Switzerland. lindsey.crowe@hcuge.ch
authors.forename: L A
authors.initials: LA
authors.lastname: Crowe
authors.forename: F
authors.initials: F
authors.lastname: Tobalem
authors.forename: A
authors.initials: A
authors.lastname: Gramoun
authors.forename: B M A
authors.initials: BM
authors.lastname: Delattre
authors.forename: K
authors.initials: K
authors.lastname: Grosdemange
authors.forename: J
authors.initials: J
authors.lastname: Salaklang
authors.forename: A
authors.initials: A
authors.lastname: Redjem
authors.forename: A
authors.initials: A
authors.lastname: Petri-Fink
authors.forename: H
authors.initials: H
authors.lastname: Hofmann
authors.forename: J-P
authors.initials: JP
authors.lastname: Vallée
mesh_terms: D000465:Algorithms; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D003911:Dextrans / Q000008:administration & dosage*; D005260:Female; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007269:Injections, Intra-Arterial; D007596:Joints / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000008:administration & dosage*; D051381:Rats; D011917:Rats, Inbred Lew; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; C097921:ferumoxtran-10