Effective contrast use in CT angiography and dual-phase hepatic CT performed with a subsecond scanner.
OBJECTIVE
To deduce an optimal injection protocol for CT angiography and fast dual-phase hepatic CT.


METHODS
Fifty-two patients underwent fast dual-phase hepatic CT using one of three different injection protocols: A (0.9 g/sec iodine injection rate, 36 g dose); B (1.35 g/sec, 30 g); C (1.6 g/sec, 40 g). Aortic attenuation time curves as well as aorta-to-liver contrast and hepatic enhancement time curves obtained by region of interest measurements along the helical axis were analyzed.


RESULTS
Protocol C revealed a significantly higher peak in aortic attenuation and hepatic enhancement than the other protocols. Approximately 50 seconds after the bolus injection, hepatic enhancement declined to a plateau similar to that seen with the other protocols. In terms of the areas under the curves of the aorta-to-liver contrast and hepatic enhancement dynamics, protocol C was significantly superior to the other protocols.


CONCLUSIONS
A high iodine injection rate realized by a high iodine concentration in conjunction with fast dual-phase scanning (total scan time < 50 seconds) promises to enhance CT angiography and contrast of liver lesions.
Luboldt
W
W
Institute of Diagnostic Radiology, University Hospital Grosshadern, Munich, Germany.
Straub
J
J
Seemann
M
M
Helmberger
T
T
Reiser
M
M
D000792:Angiography / Q000379:methods*; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006391:Hemangioma / Q000098:blood supply / Q000000981:diagnostic imaging*; D006801:Humans; D007275:Injections, Intravenous; D007472:Iohexol / Q000031:analogs & derivatives*; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide