title: Enhancement of hepatic parenchyma, aorta, and portal vein in helical CT: comparison of iodixanol and iopromide.
abstract: OBJECTIVE
  The purpose of this study was to determine hepatic, aortic, and portal vein enhancement with a new dimeric, nonionic, isotonic contrast medium (iodixanol) in a routinely performed helical CT protocol and compare enhancement characteristics with those of a monomeric, nonionic, low-osmolality contrast medium (iopromide).
  
  
  METHODS
  In 81 patients, we injected 150 ml of iodixanol (320 mg I/ml), iodixanol (300 mg I/ml), or iopromide (300 mg I/ml). Injection rate was 5 ml/sec. A dual-phase helical CT scan was obtained (first helical scan began at 30 sec. second helical scan began at 70 sec), and enhancement characteristics were assessed. Results were analyzed taking into account various intrinsic parameters of patients.
  
  
  RESULTS
  During the second imaging phase, iodixanol at 320 mg I/ml and iodixanol at 300 mg I/ml provided significantly higher enhancement of the liver (75 H, 69 H, 62 H), aorta (144 H, 140 H, 122 H), and portal vein (147 H, 147 H, 118 H) than did iopromide at 300 mg I/ml. No significant differences were observed during the first imaging phase.
  
  
  CONCLUSIONS
  The combination of higher vascular and parenchymal enhancement levels after injection of the isotonic agent may represent a different quality of tissue enhancement. Such an enhancement would be characterized more by a higher contribution of the blood pool compartment to absolute enhancement levels than by a contribution of the interstitial compartment. Further studies are needed to determine whether the use of isotonic agents effects lesion conspicuity.
authors.affiliation: Department of Radiology, Vienna General Hospital, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Graf
authors.forename: G S
authors.initials: GS
authors.lastname: Gazelle
authors.forename: S
authors.initials: S
authors.lastname: Kreuzer
authors.forename: E F
authors.initials: EF
authors.lastname: Halpern
authors.forename: P
authors.initials: P
authors.lastname: Boehm
authors.forename: G
authors.initials: G
authors.lastname: Lechner
authors.forename: P R
authors.initials: PR
authors.lastname: Mueller
mesh_terms: D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives*; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011169:Portal Vein / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; C038192:iopromide; C044834:iodixanol