title: Clinical evaluation of a computer simulated prediction model of contrast enhancement of the liver in spiral CT.
abstract: OBJECTIVE
  A software program was developed simulating a compartmental model of blood circulation based on differential equations. The aim of this study was to compare software-simulated levels of hepatic enhancement with the true values in patients and to test how many patients reach the simulated hepatic enhancement level.
  
  
  METHODS
  As software program the CT application software carebolus 2 (Siemens, Forchheim, Germany) was used. Hepatic contrast-enhancement curves were simulated prior to CT examinations to evaluate a patient specific time delay after contrast application. At the time delay, when the simulation curve showed an enhancement threshold of 40 Hounsfield Units (HU), the CT spiral scan was started applying 120 ml contrast media with 2 ml/s. The simulated curves were compared with the empiric curves of each patient.
  
  
  RESULTS
  25 of 28 patients (89%) achieved 40 HU. The mean enhancement of empiric patients curves was 46.32 +/- 11.9 HU, the mean simulated enhancement was 46.62 +/- 4.3 HU S.D. (P= 0.48). 4.4 values per patient liver could be compared with the simulation curve (122 points for 28 patients): 50% of the patient curves were within a range of 5 HU compared with the simulation curve.
  
  
  CONCLUSIONS
  Software simulation of contrast enhancement curves of the liver is a feasible and valuable method to predict individual liver enhancement curves. Improvements concerning the integration of cardiovascular parameters and preexisting liver parenchymal diseases into the simulation software have to be arranged.
authors.affiliation: Department of Diagnostic Radiology, Eberhard-Karls-Universität, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. schoeber.wogi@t-online.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schöber
authors.forename: Andreas
authors.initials: A
authors.lastname: Kopp
authors.forename: Claudia
authors.initials: C
authors.lastname: Scherf
authors.forename: Florian
authors.initials: F
authors.lastname: Mehnert
authors.forename: Martin
authors.initials: M
authors.lastname: Heuschmid
authors.forename: Stephan H
authors.initials: SH
authors.lastname: Duda
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Philippe
authors.initials: P
authors.lastname: Pereira
mesh_terms: D000328:Adult; D000368:Aged; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D008102:Liver Circulation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012984:Software; D036542:Tomography, Spiral Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide