Determining the optimal timing for early arterial phase hepatic CT imaging by measuring abdominal aortic enhancement in variable contrast injection protocols.
OBJECTIVE
To find the optimal scan timing for early arterial phase hepatic CT with adequate arterial enhancement after the aortic contrast arrival.


METHODS
Sixty patients were divided randomly into three groups, each of which received 2.0 mL/kg of the 300 mgI/mL contrast medium with an injection duration of 30 seconds (Group A, mean rate 3.6 mL/sec); of 25 seconds (B, 4.6 mL/sec); of 30 seconds (3.6 mL/sec) followed by a saline chaser (C).


RESULTS
After the contrast arrival, aortic enhancement increased rapidly for 6-15 seconds (mean, 10 seconds) to the initial peak enhancement in all groups, and then, increased moderately to the maximum aortic enhancement over the following 19, 13, and 21 seconds, respectively. The mean maximum aortic enhancement in Group B (392 HU) and C (360 HU) were significantly higher than that in A (326 HU), respectively. The difference between the initial and maximum aortic enhancement was less than 50 HU.


CONCLUSIONS
The optimal timing of the early arterial phase for hepatic CT arteriography is 10-15 seconds after the aortic arrival.
Murakami
Takamichi
T
Department of Radiology, Osaka University Graduate School of Medicine, Osaka, Japan. murakami@med.kindai.ac.jp
Onishi
Hiromitsu
H
Mikami
Koji
K
Iannaccone
Riccardo
R
Federle
Michael P
MP
Kim
Tonsok
T
Hori
Masatoshi
M
Okada
Atsuya
A
Marukawa
Taro
T
Higashihara
Hiroki
H
Passariello
Roberto
R
Nakamura
Hironobu
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013997:Time Factors
D003287:Contrast Media