Effect of contrast material injection duration and rate on aortic peak time and peak enhancement at dynamic CT involving injection protocol with dose tailored to patient weight.
OBJECTIVE
To investigate the effect of duration and rate of contrast material injection on aortic peak time and peak enhancement in an injection protocol in which the contrast material dose is adjusted according to patient weight.


METHODS
One hundred ninety-nine patients were randomly divided into three groups in which the fixed duration of contrast material injection was 25 seconds (group A) or 35 seconds (group B) or the fixed injection rate was 4.0 mL/sec (group C). Computed tomography (CT) at the L3 vertebral level was performed before and after contrast material injection. Aortic peak time, aortic peak enhancement, and period when aortic enhancement is 200 HU or greater (T200) were calculated. The Pearson product-moment correlation coefficient (r) was used to investigate relationships between patient weight and aortic peak time, aortic peak enhancement, and T200 in each group.


RESULTS
A significant correlation between aortic peak time and patient weight (r = 0.91, P <.001) was observed in group C. No significant correlations between patient weight and aortic peak time were observed in group A (r = 0.16, P =.21) or B (r = -0.05, P =.69). A significant inverse correlation between aortic peak enhancement and patient weight (r = -0.70, P <.001) was observed in group C. No significant correlations between patient weight and aortic peak enhancement were observed in group A (r = 0.09, P =.48) or B (r = 0.10, P =.41). A significant correlation between T200 and patient weight (r = 0.72, P <.001) was observed in group C. No significant correlations between patient weight and T200 were observed in group A (r = 0.12, P =.34) or B (r = 0.001, P =.99).


CONCLUSIONS
Aortic peak time, aortic peak enhancement, and T200 were closely related to injection duration in the protocol with contrast material dose determined according to patient weight.
Awai
Kazuo
K
Department of Radiology, Kinki University School of Medicine, Osaka, Japan.
Hiraishi
Kumiko
K
Hori
Shinichi
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal; D001027:Aortography / Q000379:methods* / Q000706:statistics & numerical data; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data
D003287:Contrast Media