title: Improved image quality of helical computed tomography of the head in children by iterative reconstruction.
abstract: OBJECTIVE
  Iterative reconstruction (IR) offers noise reduction and improved image quality of computed tomography (CT). Our aim was to assess the imaging quality of non-contrast helical CT of the head in children using IR.
  
  
  METHODS
  This study recruited 78 consecutive children aged ≤5 years (range: from 3 months to 5 years; mean: 1.7 years) who underwent an emergent non-enhanced helical CT of the head with no abnormal findings. The acquired data were reconstructed using filtered back projection (FBP) and sinogram-affirmed IR (SAFIRE) with strength levels of 2 (IR2) and 4 (IR4). The imaging quality of FBP, IR2 and IR4 was scored by two experienced neuroradiologists in terms of the contrast between the gray-white matter junction and artifacts from the skull at the level of the semioval center, basal ganglia and fourth ventricle. FBP, IR2 and IR4 scores were compared at each slice level. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for FBP, IR2 and IR4 and were compared among the three reconstruction algorithms.
  
  
  RESULTS
  The score of IR2 and IR4 was significantly higher than that of FBP in terms of both the contrast between the gray-white matter junction and artifacts from the skull at each slice level (P<0.001). SNR and CNR on IR4 were the highest followed by those on IR2 and FBP (P<0.001).
  
  
  CONCLUSIONS
  IR may improve the image quality of helical CT of the head in children.
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Ono
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan. Electronic address: niwat@tokai-u.jp.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Niwa
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Noriharu
authors.initials: N
authors.lastname: Yanagimachi
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan; Department of Radiology, Isehara Kyodo Hospital, 345, Tanaka, Isehara 259-1132, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Okazaki
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Takakiyo
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Hashimoto
authors.affiliation: Department of Radiology, Tokai University School of Medicine, 143, Shimokasuya, Isehara 259-1193, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
mesh_terms: D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging*; D002675:Child, Preschool; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement; D007223:Infant; D008297:Male; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012886:Skull / Q000000981:diagnostic imaging; D036542:Tomography, Spiral Computed / Q000379:methods*; D066127:White Matter / Q000000981:diagnostic imaging
keywords: Children; Head CT; Helical CT; Iterative reconstruction