title: The effect of adaptive iterative dose reduction on image quality in 320-detector row CT coronary angiography.
abstract: OBJECTIVE
  To evaluate the effect of adaptive iterative dose reduction (AIDR) on image noise and image quality as compared with standard filtered back projection (FBP) in 320-detector row CT coronary angiography (CTCA).
  
  
  METHODS
  50 patients (14 females, mean age 68 ± 9 years) who underwent CTCA (100 kV or 120 kV, 400-580 mA) within a single heartbeat were enrolled. Studies were reconstructed with FBP and subsequently AIDR. Image noise, vessel contrast and contrast-to-noise ratio (CNR) in the coronary arteries were evaluated. Overall image quality for coronary arteries was assessed using a five-point scale (1, non-diagnostic; 5, excellent).
  
  
  RESULTS
  All the examinations were performed in a single heartbeat. Image noise in the aorta was significantly lower in data sets reconstructed with AIDR than in those reconstructed with FBP (21.4 ± 3.1 HU vs 36.9 ± 4.5 HU; p<0.001). No significant differences were observed between FBP and AIDR for the mean vessel contrast (HU) in the proximal coronary arteries. Consequently, CNRs in the proximal coronary arteries were higher in the AIDR group than in the FBP group (p<0.001). The mean image quality score was improved by AIDR (3.75 ± 0.38 vs 4.24 ± 0.38; p<0.001).
  
  
  CONCLUSIONS
  The use of AIDR reduces image noise and improves image quality in 320-detector row CTCA.
authors.affiliation: Department of Radiology, Osaka Medical College, Takatsuki City, Osaka, Japan. sa104@rg8.so-net.ne.jp
authors.forename: F
authors.initials: F
authors.lastname: Tatsugami
authors.forename: M
authors.initials: M
authors.lastname: Matsuki
authors.forename: G
authors.initials: G
authors.lastname: Nakai
authors.forename: Y
authors.initials: Y
authors.lastname: Inada
authors.forename: S
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Takeda
authors.forename: H
authors.initials: H
authors.lastname: Morita
authors.forename: H
authors.initials: H
authors.lastname: Takada
authors.forename: S
authors.initials: S
authors.lastname: Yoshikawa
authors.forename: K
authors.initials: K
authors.lastname: Fukumura
authors.forename: Y
authors.initials: Y
authors.lastname: Narumi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002985:Clinical Protocols; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods* / Q000592:standards; D015588:Observer Variation; D011829:Radiation Dosage; D059629:Signal-To-Noise Ratio