title: High magnetic susceptibility coatings for visualisation of optical fibres on a specialised interventional MRI system.
abstract: The aim of this study was to develop methods of visualising optical fibres on MRI scans for monitoring interstitial laser therapy. Scans were performed on a specialised MRI extremity scanner at 0.17 T. Optical fibres of 0.4 mm diameter used for delivering laser energy were coated with iron particles from a superferromagnetic contrast agent. MR images of the fibres were acquired using gradient echo sequences (TR/TE = 300/10, 1 mm in-plane, 3 mm slice) and assessed for fibre visibility. Coated fibres could be resolved as lines 2 +/- 1 mm wide using the gradient echo sequence. Uncoated fibres were invisible on the sequences used for in vivo therapy monitoring due to partial volume averaging. It is concluded that optical fibre visualisation by MRI may be improved by coating with ferromagnetic particles. Biocompatibility requires further assessment, but direct coating appears to be a promising method for fibre visualisation in MR-guided laser therapy.
authors.affiliation: Department of Neurology, The Middlesex Hospital, University College London Hospitals NHS Trust and University College London, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Paley
authors.forename: M
authors.initials: M
authors.lastname: Clemence
authors.forename: M A
authors.initials: MA
authors.lastname: Hall-Craggs
authors.forename: I D
authors.initials: ID
authors.lastname: Wilkinson
authors.forename: W R
authors.initials: WR
authors.lastname: Lees
authors.forename: M J
authors.initials: MJ
authors.lastname: Harrison
mesh_terms: D003287:Contrast Media; D003911:Dextrans; D052203:Ferrosoferric Oxide; D005336:Fiber Optic Technology; D006801:Humans; D007501:Iron; D017075:Laser Coagulation / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D058185:Magnetite Nanoparticles; D010087:Oxides; D015642:Radiology, Interventional / Q000295:instrumentation; D013535:Suspensions
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D013535:Suspensions; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide