title: CT number-controlling system for reproducibility of intracoronary CT number on follow-up coronary CT angiography.
abstract: BACKGROUND
  Coronary computed tomography angiography (CCTA) may be useful for noninvasive follow-up; however, evaluation of coronary stenosis and CT number of plaque may be inaccurate under different vessel enhancement of contrast media. We examined the reproducibility of the CT number of repeat CCTA using our original CT number-controlling system (CTN-CS), which selects contrast level by a multiple regression equation using body surface area and peak CT number and peak time on timing bolus and during CCTA.
  
  
  RESULTS
  One hundred seventy-two patients who underwent serial CCTA were prospectively and randomly assigned to 3 groups. In the first group, Group A, the amount of contrast for the second CCTA was determined by CTN-CS to match the intracoronary CT number of the first CCTA. In Group B, each patient received the same amount of intravenous contrast in both CCTA examinations. In Group C, 0.7 mL/mg body weight (BW) of contrast medium (350 mgI/mL) was used for baseline and follow-up CCTAs. The regression of repeated CCTAs was the best in Group A (r=0.85, p<0.001) vs. Group B (r=0.52, p<0.001), and Group C (r=0.61, p<0.001). The absolute difference between intracoronary CT numbers of the second and first CCTA was the lowest in Group A (24.8 ± 21.8HU), followed by Group B (37.6 ± 26.2 HU; p<0.05) and Group C (46.5 ± 34.4HU; p<0.001).
  
  
  CONCLUSIONS
  Using CTN-CS, the difference of intracoronary CT numbers of the second and first CCTA was the smallest when compared to CCTAs using the same contrast volumes or constant volumes per body weight.
authors.affiliation: Cardiovascular Center, Amagasaki Central Hospital, Hyogo, Japan. plaquemap@yahoo.co.jp
authors.forename: Sei
authors.initials: S
authors.lastname: Komatsu
authors.forename: Atsuko
authors.initials: A
authors.lastname: Imai
authors.forename: Teruaki
authors.initials: T
authors.lastname: Kamata
authors.forename: Tomoki
authors.initials: T
authors.lastname: Ohara
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Takewa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Minamiguchi
authors.forename: Ryoko
authors.initials: R
authors.lastname: Ohe
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishiuchi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Miyaji
authors.forename: Junichi
authors.initials: J
authors.lastname: Yoshida
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Kodama
mesh_terms: D001830:Body Surface Area; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D012044:Regression Analysis; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media
keywords: Angiography; Computed tomography; Contrast media