title: Improved uniformity of aortic enhancement with customized contrast medium injection protocols at CT angiography.
abstract: OBJECTIVE
  To compare the uniformity of aortoiliac opacification obtained from uniphasic contrast medium injections versus individualized biphasic injections at computed tomographic (CT) angiography.
  
  
  METHODS
  Thirty-two patients with an abdominal aortic aneurysm underwent CT angiography. In 16 patients (group 1), 120 mL of contrast material was administered at a flow rate of 4 mL/sec. In the other 16 patients (group 2), biphasic injection protocols were computed by using mathematic deconvolution of each patient's time-attenuation response to a standardized test injection. Attenuation uniformity was quantified as the "plateau deviation" of enhancement values, which were calculated as the SD of the time-contiguous attenuation values observed during the 30-second scanning period.
  
  
  RESULTS
  Group 2 patients received between 77 and 165 mL (mean, 115 mL) of contrast medium. Initial flow rates ranged from 4.1 to 10.0 mL/sec (mean, 6.8 mL/sec) for the first 4-6 seconds; continuing flow rates ranged from 2.0 to 4.8 mL/sec (mean, 3.1 mL/sec) for the remaining 24-26 seconds. The plateau deviation was significantly smaller in group 2 patients (19 HU) versus group 1 patients (38 HU, P <.001).
  
  
  CONCLUSIONS
  At CT angiography, tailored biphasic injections led to more uniform aortoiliac enhancement, compared with standard uniphasic injections of contrast medium.
authors.affiliation: Department of Radiology, University of Vienna, AKH, Währinger Gürtel 18-20, A-1090, Austria. dominik.fleischmann@univie.ac.at
authors.forename: D
authors.initials: D
authors.lastname: Fleischmann
authors.forename: G D
authors.initials: GD
authors.lastname: Rubin
authors.forename: A A
authors.initials: AA
authors.lastname: Bankier
authors.forename: K
authors.initials: K
authors.lastname: Hittmair
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging; D001027:Aortography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D007275:Injections, Intravenous / Q000379:methods; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods*; D012212:Rheology; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media