title: Optimization of contrast material administration for electrocardiogram-gated computed tomographic angiography of the chest.
abstract: OBJECTIVE
  Electrocardiogram-gated computed tomographic angiography is increasingly used in the differential diagnosis of acute chest pain. We studied the optimal timing of contrast material injection using a test bolus and a bolus-tracking technique.
  
  
  METHODS
  Thirty patients were prospectively included in the study. Volume and flow of high concentration contrast material were adapted to body weight. The scan delay was determined using either a test bolus or a bolus-tracking technique. Attenuation profiles of the different vascular districts were measured to evaluate the timing techniques.
  
  
  RESULTS
  In all the patients except for one, an adequate and homogeneous contrast enhancement of more than 200 Hounsfield units (HU) was achieved (285 +/- 45 HU) in the different vascular districts. The pulmonary transit time in the test bolus group was 7 seconds (range, 4-11 seconds). Differences and variability of pulmonary and aortic enhancement were small in both groups (13 +/- 48 HU vs -9 +/- 21 HU), with differences of less than 70 HU over the craniocaudal range and very small intraindividual differences between pulmonary attenuation and systemic attenuation.
  
  
  CONCLUSIONS
  Contrast administration regimens for electrocardiogramgated computed tomographic angiography of the chest can be optimized using the bolus-tracking method in the ascending aorta, with a short delay after trigger. Body weight adaptation of volume and injection rate of the contrast material results in a reliable simultaneous opacification of the pulmonary and systemic vasculature.
authors.affiliation: Department of Clinical Radiology, Medical Clinic I, University of Munich-Grosshadern Campus, Marchioninistrasse, Munich, Germany. thorsten.johnson@med.uni-muenchen.de
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Wintersperger
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
authors.forename: Carsten
authors.initials: C
authors.lastname: Rist
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Leber
authors.forename: Andreas
authors.initials: A
authors.lastname: Knez
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Becker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001027:Aortography / Q000379:methods; D001835:Body Weight; D002637:Chest Pain / Q000209:etiology; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000175:diagnosis*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008171:Lung Diseases / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide