Hepatic helical CT: contrast material injection protocol.
OBJECTIVE
To develop and compare contrast material injection protocols suitable for hepatic helical computed tomography (CT).


METHODS
Monophasic and biphasic helical CT were performed with contrast material with an iodine load of 50 g at 3 mL/sec for 60 seconds or at 5 mL/sec for 10 seconds and 2 mL/sec for 65 seconds, respectively. In 58 men and 51 women, aged 22-77 years, aortic and hepatic enhancement curves were constructed from a cluster acquisition with a slip-ring scanner operating in a nonhelical mode.


RESULTS
The monophasic protocol produced a higher peak aortic enhancement (180 HU +/- 47 [+/- 1 standard deviation]) than the biphasic protocol (150 HU +/- 24). Peak hepatic enhancement (63-64 HU +/- 15) was equivalent. Calculated equilibrium time for the monophasic protocol was 95.1 seconds and for the biphasic protocol was 101.4 seconds. The contrast enhancement index differed only marginally between the two protocols (P < .4).


CONCLUSIONS
Monophasic and biphasic protocols produced equivalent results when tailored for the shorter temporal window of a rapid-sequence helical acquisition.
Department of Radiology, Medical College of Wisconsin, Milwaukee 53226.
W D
WD
Foley
R G
RG
Hoffmann
F A
FA
Quiroz
C E
CE
Kahn
R S
RS
Perret
D000328:Adult; D000368:Aged; D001027:Aortography; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media