title: Improvement in image quality of noncontrast head images in multidetector-row CT by volume helical scanning with a three-dimensional denoising filter.
abstract: OBJECTIVE
  The aim of this study was to improve the contrast-to-noise ratio on noncontrast head computed tomography (CT) images, which are crucial for assessing patients with acute ischemic stroke. We applied a technique combining volume helical scanning with a three-dimensional (3D) denoising filter.
  
  
  METHODS
  We scanned phantoms for low-contrast resolutions and helical/cone-beam artifacts as well as stroke patients using a 16-row multidetector-row CT (MDCT) unit. Volume helical scans with 1-mm collimation and nonhelical scans with 8-mm thickness were performed. From the 1-mm thick volume data, 8-mm thick contiguous images were generated before and after applying a 3D denoising filter.
  
  
  RESULTS
  On images stacked from volume data, the contrast-to-noise ratio was significantly improved by the 3D denoising filter and was nearly the same as that on nonhelical images. On stacked volume images, artifacts due to the cone beam and the helical scan were increased with larger helical pitches, but bone-related streak artifacts in the posterior fossa and underneath the calvarium were reduced when compared with nonhelical images.
  
  
  CONCLUSIONS
  Volume helical scan with a 3D denoising filter effectively improves image quality in noncontrast head MDCT images.
authors: Center for Radiological Sciences, Iwate Medical University Hospital, 19-1 Uchimaru, Morioka, 020-8505, Japan. sasachu2555@ybb.ne.jp
authors: Tadashi
authors: T
authors: Sasaki
authors: Makoto
authors: M
authors: Sasaki
authors: Takao
authors: T
authors: Hanari
authors: Hiroshi
authors: H
authors: Gakumazawa
authors: Yasuhiro
authors: Y
authors: Noshi
authors: Miwa
authors: M
authors: Okumura
mesh_terms: D000704:Analysis of Variance; D016477:Artifacts; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D020521:Stroke / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed / Q000295:instrumentation*
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