title: Homogeneous enhancement in pediatric thoracic CT aortography using a novel and reproducible method: contrast-covering time.
abstract: OBJECTIVE
  This study compares the empiric setting and contrast-covering time (CCT) concept for i.v. contrast injection in pediatric thoracic CT aortography.
  
  
  METHODS
  A total of 113 pediatric patients referred for thoracic CT aortography were classified into four groups: group 1 (1-5 years old, CCT), group 2A (6-10 years old, CCT), group 2B (6-10 years old, empiric setting), and group 3 (11-15 years old, CCT). The CT attenuation values from the left common carotid artery to the descending aorta were recorded every 0.5 second. The quantitative bolus geometric analysis of each group included average enhancement, SD within the patient, and slope of enhancement. Groups 2A and 2B were compared to determine whether better bolus geometry could be obtained with the CCT concept than with the traditional empiric setting. Groups 1, 2A, and 3 were compared to determine whether homogeneous bolus geometry could be obtained in different age groups.
  
  
  RESULTS
  More homogeneous enhancement was obtained with the CCT concept than the empiric setting with a smaller SD of enhancement (25.5 +/- 8.5 H vs 49.3 +/- 16.2 H, p < 0.001). Furthermore, in the three different age groups (groups 1, 2A, and 3) examined using the CCT concept, there was no significant difference in the average enhancement (415.7 +/- 83.6 H, 422.8 +/- 97.1 H, 392.0 +/- 78.5 H, respectively; all p > 0.05), SD of enhancement (28.5 +/- 9.8 H, 25.5 +/- 8.5 H, 28.5 +/- 14.6 H, respectively; all p > 0.05), or enhancement slopes (-5.6 +/- 18.0 H, -2.7 +/- 10.7 H, -5.4 +/- 12.3 H, respectively; all p > 0.05).
  
  
  CONCLUSIONS
  The CCT concept yields more homogeneous enhancement than the empiric setting. It also can routinely obtain homogeneous bolus geometry in patients in different age groups.
authors: Department of Radiology, Taichung Veterans General Hospital, No. 160, Sec. 3, Taichung Harbor Rd., Taichung 407, Taiwan, ROC.
authors: I-Chen
authors: IC
authors: Tsai
authors: Tain
authors: T
authors: Lee
authors: Min-Chi
authors: MC
authors: Chen
authors: Wei-Lin
authors: WL
authors: Tsai
authors: Pao-Chun
authors: PC
authors: Lin
authors: Wan-Chun
authors: WC
authors: Liao
mesh_terms: D001013:Aorta, Thoracic; D001018:Aortic Diseases / Q000150:complications / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D013997:Time Factors; D014057:Tomography, X-Ray Computed