title: Soft and intermediate plaques in coronary arteries: how accurately can we measure CT attenuation using 64-MDCT?
abstract: OBJECTIVE
  The objective of this study was to validate the accuracy of 64-MDCT densitometry of soft and intermediate plaques.
  
  
  METHODS
  Acrylonitrile-butadiene-styrene resin (47 H) and acrylic (110 H) were used to simulate soft and intermediate plaques, respectively, in coronary artery models (diameters of 3 and 4 mm). The variable parameters were heart rate (50, 65, 80, and 95 beats per minute), reconstruction algorithm (half and segmentation), coronary artery enhancement (150, 250, 350, and 450 H), CT densitometry site (arterial lumen or center), shape of plaque (D-shaped, centric, and eccentric), and level of stenosis due to plaque (25%, 50%, and 75% of arterial diameter). Measured CT attenuation values of soft and intermediate plaques were compared for different combinations of parameters. Repeated measures analysis of variance, Wilcoxon's signed rank, Mann-Whitney U, and Kruskal-Wallis tests were used for statistical analyses.
  
  
  RESULTS
  For measuring soft plaque, CT densitometry was accurate at low heart rates with the use of a half reconstruction algorithm (p < 0.01) on intracoronary artery enhancement of 250 H (p < 0.01). For both soft and intermediate plaques, the densitometry measurements near the arterial lumen were overestimated and higher than those at the center (p < 0.01). For plaques that were 50% or more of the arterial diameter, accurate CT densitometry was possible.
  
  
  CONCLUSIONS
  Coronary artery enhancement has a significant impact on 64-MDCT densitometry measurements of coronary artery plaques, especially of soft plaques. A large plaque size, densitometry performed not near the arterial lumen but at the center of the plaque, intracoronary enhancement of 250 H, and a low heart rate increase the accuracy of plaque densitometry.
authors: Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima, 734-8551, Japan.
authors: Jun
authors: J
authors: Horiguchi
authors: Chikako
authors: C
authors: Fujioka
authors: Masao
authors: M
authors: Kiguchi
authors: Yun
authors: Y
authors: Shen
authors: Christian E
authors: CE
authors: Althoff
authors: Hideya
authors: H
authors: Yamamoto
authors: Katsuhide
authors: K
authors: Ito
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000145:classification / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*