Background: To optimize hepatic arterial phase timing in contrast-enhanced dynamic ultrasonography (US) of the liver.
Methods: Dynamic US was performed by using a microbubble-specific mode in 22 healthy volunteers after bolus injection of SH U 508A. Images were analyzed to determine whether hepatic arterial and portal venous phases could be temporally discriminated. Delay times to contrast enhancement at the hepatic artery (A(ini)) and portal vein (P(ini)) and the delay time until the signals between both vessels became inseparable (A(end)) were determined.
Results: The hepatic arterial and portal venous phases could be temporally discriminated in all subjects. A(ini), P(ini), and A(end) (mean +/- standard deviation) were 11.0 +/- 2.0, 14.8 +/- 3.6, and 22.6 +/- 5.1 s, respectively.
Conclusion: In hepatic contrast-enhanced dynamic US, hepatic arterial phase scanning should be commenced earlier than 11 s and terminated after 23 s postinjection.