title: Effects of heart rate on motion artifacts of the aorta on non-ECG-assisted 0.5-sec thoracic MDCT.
abstract: OBJECTIVE
  Our aim was to evaluate the effects of heart rate on aortic motion artifacts on 0.5-sec non-ECG-assisted thoracic MDCT.
  
  
  METHODS
  A total of 124 non-ECG-assisted thoracic MDCT scans with satisfactory simultaneous ECG data were reviewed. Scans were grouped according to patient heart rates (beats per minute [bpm]: group A, 46-55; B, 56-65; C, 66-75; D, 76-85; E, 86-95; and F > 95). The groups were compared regarding the presence, locations, and spatial distributions of pulsation artifact, number of slices affected, maximum amplitude of pulsation, continuity of artifact, and the presence of superior vena cava (SVC) pseudoflaps.
  
  
  RESULTS
  Of the 124 scans, 114 (91.9%) had aortic motion artifacts, with prevalence ranging from 85.3% (66-75 bpm) to 100% (65 bpm or less). Of the 114 motion artifacts, all affected the ascending aorta, 105 (92.1%) involved the left anterior and right posterior aspects of the aortic circumference, and 106 (93%) were associated with SVC pseudoflaps. Group B had significantly greater numbers of images with artifacts (p < 0.001-0.006), greater artifact amplitudes (p < 0.001-0.002), and a higher continuity trend for the artifacts (p = 0.003-0.194) than did the other five groups.
  
  
  CONCLUSIONS
  Aortic motion artifacts are frequently seen on thoracic MDCT, especially in patients with heart rates of 65 bpm or less. The presence of a SVC pseudoflap is helpful for distinguishing artifacts from dissection. If aortic disease is suspected, then measures to reduce motion artifact, such as ECG-gating, should be considered.
authors.affiliation: Department of Radiology, Chang Gung Memorial Hospital at Kaohsiung, Chang Gung University, 123 Ta-Pei Rd., Niao-Sung Hsiang, Kaohsiung Hsien 833, Taiwan. sfatko@adm.cgmh.org.tw
authors.forename: Sheung-Fat
authors.initials: SF
authors.lastname: Ko
authors.forename: Ming-Jeng
authors.initials: MJ
authors.lastname: Hsieh
authors.forename: Min-Chi
authors.initials: MC
authors.lastname: Chen
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Fu-Min
authors.initials: FM
authors.lastname: Fang
authors.forename: Chung-Cheng
authors.initials: CC
authors.lastname: Huang
authors.forename: Yung-Liang
authors.initials: YL
authors.lastname: Wan
authors.forename: Tze-Yu
authors.initials: TY
authors.lastname: Lee
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000502:physiology*; D016477:Artifacts; D003287:Contrast Media; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009038:Motion; D013902:Radiography, Thoracic; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media