title: A non-invasive cardiac output measurement as an alternative to the test bolus technique during CT angiography.
abstract: OBJECTIVE
  To investigate the association between a non-invasive cardiac output (CO) measurement and the scan delay, as derived from a test bolus injection protocol. The secondary objective was to determine which factors affect the relationship between the CO and scan delay.
  
  
  METHODS
  Fifty-five patients referred for a contrast-enhanced (thorax-)abdomen CT examination were included in this feasibility study. A test bolus examination was performed prior to the abdominal CT. During the test bolus injection, the CO of the patient was measured using a non-invasive finger-cuff measurement. Associations were analysed using linear regression analyses. Age, gender, height, weight, and blood pressure were included as potential confounders.
  
  
  RESULTS
  Linear regression analysis showed a negative and significant association between CO and delay. The regression formula was as follows: scan delay (seconds) = 26.8-1.6 CO (l/min), with a 95% CI between -2.3 and -1.0 (p<0.001). Weight appeared to be a confounder in this relation, and gender and blood pressure were effect modifiers. There was no interaction between scan delay and age, height and weight.
  
  
  CONCLUSIONS
  There is a negative and significant association between the non-invasive CO measurement and the CT scan delay; however, to validate these findings a larger cohort study is needed to investigate whether the non-invasively determined scan delay is as accurate as the use of a test bolus.
authors.affiliation: University of Twente, MIRA-Institute for Biomedical Technology and Technical Medicine, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands; Department of Radiology, Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ, 's-Hertogenbosch, The Netherlands. Electronic address: w.h.nijhof@gmail.com.
authors.forename: W H
authors.initials: WH
authors.lastname: Nijhof
authors.affiliation: Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ, 's-Hertogenbosch, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Hilbink
authors.affiliation: Department of Radiology, Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ, 's-Hertogenbosch, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Jager
authors.affiliation: University of Twente, MIRA-Institute for Biomedical Technology and Technical Medicine, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands.
authors.forename: C H
authors.initials: CH
authors.lastname: Slump
authors.affiliation: Department of Radiology, Jeroen Bosch Hospital, Henri Dunantstraat 1, 5223 GZ, 's-Hertogenbosch, The Netherlands.
authors.forename: M J C M
authors.initials: MJ
authors.lastname: Rutten
mesh_terms: D001011:Aorta / Q000378:metabolism*; D001027:Aortography / Q000379:methods*; D002302:Cardiac Output / Q000502:physiology*; D000072226:Computed Tomography Angiography / Q000379:methods*; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006334:Heart Function Tests / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014283:Triiodobenzoic Acids / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C054871:ioversol