title: Reduction of guide needle streak artifact in CT-guided biopsy.
abstract: OBJECTIVE
  Computed tomography (CT)-guided core needle biopsy (CNB) can be affected by streak artifact obscuring the needle tip. This study investigates factors that influence the occurrence and severity of streak artifact during CNB.
  
  
  METHODS
  Eight coaxial guide needles of two sizes from two manufacturers with and without stylets were imaged in a CT phantom, with CT reconstructed with adaptive statistical iterative reconstruction and filtered back projection. CNB-related streak artifact was quantified with profile analysis in an image-processing program. Differences between maximum attenuation at the needle tip and minimum attenuation in the streak artifact were compared for each variable. Diagnostic acceptability and streak artifact were subjectively assessed on each phantom image and on 40 clinical CNB procedures by three independent blinded reviewers following training case review.
  
  
  RESULTS
  Artifact was significantly less with the central stylet removed versus in situ (median, 1,145 HU vs 3,390 HU; P < .001) for all needles, and less for 19-gauge needles versus 17-gauge needles (median, 1,334 HU vs 2,780 HU, respectively; P = .006). There were no differences based on manufacturer (P = .906) or reconstruction algorithm (P = .524). Independent reviews found that streak artifact was significantly reduced when the central stylet was removed (κ = 0.875-1.0; P < .001), and needle tip position was better in cases in which the stylet was removed (κ = 0.231-0.711; P < .001).
  
  
  CONCLUSIONS
  Streak artifact can be reduced and needle tip visualization improved by confirming final biopsy needle position with the central stylet removed on CT and using smaller-gauge guide needles.
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland.
authors.forename: Sebastian R
authors.initials: SR
authors.lastname: McWilliams
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Murphy
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland.
authors.forename: Safieh
authors.initials: S
authors.lastname: Golestaneh
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: O'Regan
authors.affiliation: Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, 55 Fruit St., Boston, MA 02114.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Arellano
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Maher
authors.affiliation: Department of Radiology, University College Cork, Cork University Hospital and Mercy University Hospital, Cork, Ireland; Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, 55 Fruit St., Boston, MA 02114. Electronic address: oj.oconnor@ucc.ie.
authors.forename: Owen J
authors.initials: OJ
authors.lastname: O'Connor
mesh_terms: D016477:Artifacts; D062005:Biopsy, Large-Core Needle / Q000295:instrumentation / Q000379:methods; D001707:Biopsy, Needle; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D061705:Image-Guided Biopsy / Q000295:instrumentation / Q000379:methods; D015588:Observer Variation; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*