title: Image quality and radiation exposure in CT of the pancreas: 320-MDCT with and without adaptive iterative dose reduction versus 64-MDCT.
abstract: OBJECTIVE
  To compare the image quality and radiation exposure in computed tomography (CT) of the pancreas acquired using 320-multidetector (MD)CT versus 64-MDCT and to demonstrate the effects of adaptive iterative dose reduction (AIDR) on 320-MDCT.
  
  
  METHODS
  One hundred and fifty patients were randomized into three groups including 320-section volume imaging using AIDR (group A), 320-slice volume scan without AIDR (group B), and 64-section helical imaging without AIDR (group C). Transaxial arterial, pancreatic phase, and volume-rendered CT angiographic images were reconstructed. CT radiodensity of the abdominal aorta, pancreas, signal-to-noise ratios (SNR), dose-length products (DLPs; mGy cm), and image quality were measured.
  
  
  RESULTS
  No significant difference in CT radiodensity of the abdominal aorta or pancreas was noted between groups. Mean DLPs were 600.9 ± 145.8, 681.6 ± 97.5, and 1231.5 ± 271.4 in groups A, B, and C, respectively. The DLP was reduced by 51% in group A and 45% in group B compared to group C (p < 0.001). SNRs of the pancreas during the pancreatic phase were comparable between groups A and C, but were significantly lower in group B (p < 0.001). Image quality, including the depiction of some small arterial branches on the arterial and CT angiographic images and the main pancreatic duct on the pancreatic-phase images, were significantly lower in group B than in groups A and C (p = 0.008-0.038).
  
  
  CONCLUSIONS
  Radiation dose can be markedly reduced for contrast-enhanced CT imaging of the pancreas without compromising image quality using a 320-MDCT with AIDR, compared with 64-section helical CT.
authors.affiliation: Department of Radiology, Gifu University Hospital, Gifu, Japan. Electronic address: gossy@par.odn.ne.jp.
authors.forename: S
authors.initials: S
authors.lastname: Goshima
authors.forename: M
authors.initials: M
authors.lastname: Kanematsu
authors.forename: H
authors.initials: H
authors.lastname: Nishibori
authors.forename: D
authors.initials: D
authors.lastname: Miyazawa
authors.forename: H
authors.initials: H
authors.lastname: Kondo
authors.forename: N
authors.initials: N
authors.lastname: Moriyama
authors.forename: K T
authors.initials: KT
authors.lastname: Bae
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010179:Pancreas / Q000000981:diagnostic imaging*; D010182:Pancreatic Diseases / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D036542:Tomography, Spiral Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D007472:Iohexol