title: Intravenous contrast material administration at 16-detector row helical CT coronary angiography: test bolus versus bolus-tracking technique.
abstract: OBJECTIVE
  To compare test bolus and bolus-tracking techniques for intravenous contrast material administration at 16-detector row computed tomographic (CT) coronary angiography.
  
  
  METHODS
  This study had institutional review board approval, and patients gave informed consent. Thirty-eight patients (mean age, 60 years; three women) were randomized into two groups according to bolus timing technique: group 1 (20-mL test bolus with 100-mL main bolus) and group 2 (bolus tracking with 100-mL main bolus). All patients underwent electrocardiography-gated 16-detector row CT coronary angiography with 12 detectors (collimation, 0.75 mm; rotation time, 420 msec). In group 1, test bolus peak attenuation was used as a delay, while in group 2, a +100-HU threshold in ascending aorta triggered angiographic acquisition, with an additional 4-second delay for patient instruction. Attenuation was measured in the longitudinal direction throughout the examination in three main vessels: ascending aorta (region of interest [ROI] 1), descending aorta (ROI 2), and main pulmonary artery (ROI 3). Mean attenuation and slope of bolus geometry curve were calculated in each patient and ROI. Attenuation at origin of coronary arteries was measured. Student t test was used to compare results.
  
  
  RESULTS
  Mean scan delay was 6 seconds longer in group 2 (P < .05). Average attenuation values were 306.6 HU +/- 44.0 (standard deviation) and 328.2 HU +/- 58.6 (P > .05) in ROI 1, 291.6 HU +/- 45.1 and 326.4 HU +/- 62.6 (P > .05) in ROI 2, and 354.7 HU +/- 78.0 and 305.3 HU +/- 71.4 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average slope values were 5.8 and -0.8 (P < .05) in ROI 1, 7.7 and 0.7 (P < .05) in ROI 2, and -1.0 and -13.3 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average attenuation values in left main, left anterior descending, and left circumflex arteries were higher in group 2 (P < .05); there were no differences (P > .05) between groups in right coronary artery.
  
  
  CONCLUSIONS
  Bolus-tracking yields more homogeneous enhancement than does the test bolus technique.
authors.affiliation: Department of Radiology, Erasmus Medical Center, Dr Molenwaterplein 40, 3015 GD Rotterdam, the Netherlands. filippocademartiri@hotmail.com
authors.forename: Filippo
authors.initials: F
authors.lastname: Cademartiri
authors.forename: Koen
authors.initials: K
authors.lastname: Nieman
authors.forename: Aad
authors.initials: A
authors.lastname: van der Lugt
authors.forename: Rolf H
authors.initials: RH
authors.lastname: Raaijmakers
authors.forename: Nico
authors.initials: N
authors.lastname: Mollet
authors.forename: Peter M T
authors.initials: PM
authors.lastname: Pattynama
authors.forename: Pim J
authors.initials: PJ
authors.lastname: de Feyter
authors.forename: Gabriel P
authors.initials: GP
authors.lastname: Krestin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging; D001027:Aortography; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D013997:Time Factors; D036542:Tomography, Spiral Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000008:administration & dosage
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol