title: Biopsy needle artifact localization in MRI-guided robotic transrectal prostate intervention.
abstract: Recently a number of robotic intervention systems for magnetic resonance image (MRI)-guided needle placement in the prostate have been reported. In MRI-guided needle interventions, after a needle is inserted, the needle position is often confirmed with a volumetric MRI scan. Commonly used titanium needles are not directly visible in an MRI, but they generate a susceptibility artifact in the immediate neighborhood of the needle. This paper reports the results of a quantitative study of the relationship between the true position of titanium biopsy needle and the corresponding needle artifact position in MRI, thereby providing a better understanding of the influence of needle artifact on targeting errors. The titanium needle tip artifact extended 9 mm beyond the actual needle tip location with tendency to bend toward the scanner's B  (0) magnetic field direction, and axially displaced 0.38 and 0.32 mm (mean) in scanner's frequency and phase encoding direction, respectively.
authors.affiliation: Johns Hopkins University, Baltimore, MD 21202, USA. sam0song@gmail.com
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Song
authors.forename: Nathan Bongjoon
authors.initials: NB
authors.lastname: Cho
authors.forename: Iulian I
authors.initials: II
authors.lastname: Iordachita
authors.forename: Peter
authors.initials: P
authors.lastname: Guion
authors.forename: Gabor
authors.initials: G
authors.lastname: Fichtinger
authors.forename: Aradhana
authors.initials: A
authors.lastname: Kaushal
authors.forename: Kevin
authors.initials: K
authors.lastname: Camphausen
authors.forename: Louis L
authors.initials: LL
authors.lastname: Whitcomb
mesh_terms: D016477:Artifacts; D001707:Biopsy, Needle / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008954:Models, Biological; D009339:Needles; D019047:Phantoms, Imaging; D011467:Prostate / Q000601:surgery*; D012371:Robotics; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014025:Titanium
chemical_list: D014025:Titanium