title: Evaluation of Metallic Artifacts Caused by Nonpenetrating Titanium Clips in Postoperative Neuroimaging.
abstract: BACKGROUND
  Nonpenetrating titanium clips create no suture holes and thereby reduce cerebrospinal fluid leakage after dural closure. However, no data exist regarding metallic artifacts caused by these clips during postoperative neuroimaging. We aimed to evaluate clip-related artifacts on postoperative magnetic resonance (MR) images of 17 patients who underwent spinal surgery.
  
  
  METHODS
  A phantom study evaluated the size of metallic artifacts, and a clinical study evaluated the quality of postoperative spinal MR images. Both 1.5-T studies used T1-weighted and T2-weighted fast spin echo sequences. The phantom study compared clip and artifact size for 10 clips. Artifacts were defined as signal voids surrounded by high signal amplitude that followed the clip shape. In the clinical study, 2 neurosurgeons assessed 22 images from 17 patients of the spinal cord, cauda equina, and paravertebral muscles adjacent to the nonpenetrating titanium clips, using 5-point scales.
  
  
  RESULTS
  Mean metallic artifact sizes were 4.82 ± 0.16 mm (T1) and 4.66 ± 0.25 mm (T2; P < 0.001 vs. control). The former and latter were respectively 207% and 200% larger than the clip size. Both readers graded spinal cord and paravertebral muscles images as 3 or 4, indicating very good image quality regardless of clip-related artifacts, with excellent interobserver agreement (κ = 0.99 and 0.98, respectively).
  
  
  CONCLUSIONS
  Metallic artifacts caused by nonpenetrating titanium clips were 200% larger than the actual clip but did not affect spinal cord and extradural tissue visualization. The use of these clips for closing the spinal dura mater does not alter postoperative radiologic evaluation quality.
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan. Electronic address: kitoh@shinshu-u.ac.jp.
authors: Kiyoshi
authors: K
authors: Ito
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Tatsuya
authors: T
authors: Seguchi
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Takuya
authors: T
authors: Nakamura
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Akihiro
authors: A
authors: Chiba
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Takatoshi
authors: T
authors: Hasegawa
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Alhusain
authors: A
authors: Nagm
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Tetsuyoshi
authors: T
authors: Horiuchi
authors: Department of Neurosurgery, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors: Kazuhiro
authors: K
authors: Hongo
mesh_terms: D001164:Arteriovenous Fistula / Q000601:surgery; D016477:Artifacts; D064131:Back Muscles / Q000000981:diagnostic imaging*; D020785:Central Nervous System Vascular Malformations / Q000601:surgery; D065634:Cerebrospinal Fluid Leak / Q000517:prevention & control; D004388:Dura Mater / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000601:surgery; D008579:Meningioma / Q000601:surgery; D008875:Middle Aged; D009442:Neurilemmoma / Q000601:surgery; D059906:Neuroimaging; D019047:Phantoms, Imaging; D011184:Postoperative Period; D013116:Spinal Cord / Q000000981:diagnostic imaging*; D013525:Surgical Instruments; D014025:Titanium; D058106:Wound Closure Techniques / Q000295:instrumentation
chemical_list: D014025:Titanium
keywords: Cerebrospinal fluid leakage; Dural closure; Magnetic resonance imaging; Metallic artifacts; Nonpenetrating clips; Spinal surgery