title: Uptake of a superparamagnetic contrast agent imaged by MR with high spectral and spatial resolution.
abstract: Conventional MRI implicitly treats the proton signal as a single, narrow Lorentzian. However, water signals in vivo are often in homogeneously broadened and have multiple resolvable components. These components represent discrete populations of water molecules within each pixel which are affected differently by physiology and contrast agents. Accurate measurement of each component of the water resonance can improve anatomic and functional MR images and provide insight into the structure and dynamics of subpixelar microenvironments. This report describes high spectral and spatial resolution (HiSS) MR imaging of rodent prostate tumors before and after injection of a superparamagnetic contrast agent. HiSS datasets were used to synthesize images in which intensity is proportional to peak height, peak frequency, and linewidth. These images showed anatomic features which were not clearly delineated in conventional T(2) and gradient echo images. HiSS images obtained after injection of the contrast agent showed T *(2) and T(1) changes which were not seen in conventional images. These changes are associated with microvessel density and permeability. The results suggest HiSS with superparamagnetic contrast agents has the potential to improve characterization of tumors.
authors.affiliation: Department of Radiology, University of Chicago, IL 60637, USA. gskarczm@midway.uchicago.edu
authors.forename: G S
authors.initials: GS
authors.lastname: Karczmar
authors.forename: X
authors.initials: X
authors.lastname: Fan
authors.forename: H A
authors.initials: HA
authors.lastname: Al-Hallaq
authors.forename: M
authors.initials: M
authors.lastname: Zamora
authors.forename: J N
authors.initials: JN
authors.lastname: River
authors.forename: C
authors.initials: C
authors.lastname: Rinker-Schaeffer
authors.forename: M
authors.initials: M
authors.lastname: Zaucha
authors.forename: K
authors.initials: K
authors.lastname: Tarlo
authors.forename: K
authors.initials: K
authors.lastname: Kellar
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism; D003287:Contrast Media / Q000493:pharmacokinetics*; D003911:Dextrans; D052203:Ferrosoferric Oxide; D006614:Hindlimb; D007501:Iron / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D010087:Oxides / Q000493:pharmacokinetics*; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000378:metabolism*; D051381:Rats; D012815:Signal Processing, Computer-Assisted; D014407:Tumor Cells, Cultured
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide