title: Simulation of aortic peak enhancement on MDCT using a contrast material flow phantom: feasibility study.
abstract: OBJECTIVE
  The objective of our study was to develop a flow phantom simulating aortic peak enhancement after the injection of contrast material on CT and to investigate the validity of the flow phantom by comparing the time-enhancement curves obtained for the flow phantom and humans.
  
  
  METHODS
  We developed a flow phantom simulating the enhancement pattern of the aorta after the injection of contrast material. In protocols 1, 2, and 3 of the phantom study, 90, 102, and 150 mL of iohexol, respectively, was administered over 35 sec. In protocol 4, 102 mL of iohexol was administered over 25 sec. In phantom protocols 1', 2', and 3', the dose and contrast injection duration were the same as in protocols 1, 2, and 3; however, saline (10 mL) was injected during the 20 sec after contrast delivery. In the human study, 20 patients were randomized into four groups: Groups A, B, and C received 1.5, 1.7, and 2.5 mL of iohexol per kilogram of body weight, respectively, over 35 sec; and group D received 1.7 mL/kg over 25 sec. In patient groups A, B, C, and D, phantom protocols 1, 2, 3, and 4 were used, respectively. Single-level serial CT scans were obtained using a 16-MDCT scanner on the simulated and real aortas after the injection of contrast material. Time-enhancement curves of simulated and real aortas were generated, and aortic peak times and aortic peak enhancement values were calculated.
  
  
  RESULTS
  Aortic peak enhancement and aortic peak times in protocols 1-4 and 1'-3' of the phantom study were 2-8% larger and 6-18% longer, respectively, than in the corresponding patient study. The shape of the time-enhancement curves before aortic peak time in protocols 1-3 and 1'-3' of the phantom study closely resembled that of the corresponding patient study. After the aortic peak time, the shape of time-enhancement curves in protocols 1, 2, and 3 of the phantom study was different from the corresponding patient study; however, it was similar in phantom protocols 1'-3' and the corresponding patient study. In all four phantom protocols, the difference between maximal and minimal aortic peak enhancement was less than the SD of the corresponding patient study.
  
  
  CONCLUSIONS
  The level of peak aortic enhancement and the time to peak aortic enhancement were similar in the phantom and human studies when we used our different contrast injection protocols for MDCT.
authors.affiliation: Department of Diagnostic Radiology, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjyo, Kumamoto 860-8556, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hatcho
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kusunoki
authors.forename: Duo
authors.initials: D
authors.lastname: Liu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hatemura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Funama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Denbo
authors.forename: Natsuko
authors.initials: N
authors.lastname: Sato
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol