title: Carbon fibre and nitinol needles for MRI-guided interventions: first in vitro and in vivo application.
abstract: OBJECTIVE
  To assess the artefact properties of a MR-compatible carbon fibre needle with a nitinol mandrin in vitro and to report first clinical experiences.
  
  
  METHODS
  In vitro, the carbon fibre/nitinol needle was imaged at different angles against the main magnetic field (1.5T open bore magnet). A gradient echo MR fluoroscopy sequence (GRE: TR 9.3 ms, TE 3.12 ms, bandwidth 200 Hz/pixel, flip-angle 12°) and a fast turbo spin echo sequence (FSE: TR 412 ms, TE 9.7 ms, bandwidth 200 Hz/pixel, flip-angle 150°) were used. Artefact width, needle intensity contrast and needle tip location errors were assessed. In vivo, lumbar periradicular corticosteroid injections and one sclerotherapy were performed with carbon fibre needles (10 procedures) and with titanium alloy needles (2 procedures). The artefact sizes and contrasts were measured.
  
  
  RESULTS
  In vitro, artefact diameters of the carbon fibre needle ranged from 3.3 to 4.6 mm, contrasts from 0.11 to 0.52, with larger artefact contrasts and widths with the GRE sequence. Needle tip location errors of -2.1 to -2.8 mm were observed. Decreasing angles to the main field lead to smaller artefacts. In vivo, the carbon fibre/nitinol needle produced smaller artefacts (mean width FSE/GRE: 2.8mm/4.6mm) with lower contrast (0.30-0.42) than the titanium alloy needle (mean width FSE/GRE: 4.1 mm/7.5 mm, contrast 0.60-0.73).
  
  
  CONCLUSIONS
  The carbon fibre/nitinol needle is useful for performing MR-guided interventions at 1.5T, producing more subtle artefacts than a titanium alloy needle, but with an incomplete depiction and thus inaccurate localization of the needle tip.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany. Christoph.thomas@med.uni-tuebingen.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.forename: Hanne
authors.initials: H
authors.lastname: Wojtczyk
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Rempp
authors.forename: Stephan
authors.initials: S
authors.lastname: Clasen
authors.forename: Marius
authors.initials: M
authors.lastname: Horger
authors.forename: Christoph
authors.initials: C
authors.lastname: von Lassberg
authors.forename: Jan
authors.initials: J
authors.lastname: Fritz
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Philippe L
authors.initials: PL
authors.lastname: Pereira
mesh_terms: D000497:Alloys; D016477:Artifacts; D002244:Carbon; D000077482:Carbon Fiber; D003287:Contrast Media / Q000008:administration & dosage; D004867:Equipment Design; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation*; D009339:Needles; D019047:Phantoms, Imaging; D015911:Sclerotherapy / Q000295:instrumentation; D013129:Spinal Puncture / Q000295:instrumentation
chemical_list: D000497:Alloys; D000077482:Carbon Fiber; D003287:Contrast Media; C013616:nitinol; D002244:Carbon; D019786:Gadolinium DTPA