Purpose : To determine the potential usefulness of dynamic contrast-enhanced power Doppler(PD) sonography(US) in the characterization of hepatic hemangiomas.
Materials and Methods : Contrast-enhanced PD US was performed in 17 patients with hepatic hemangiomas with a HDI 3000 scanner and a 4-2 MHz convex transducer according to a standardized examination protocol(PRF, 1000 Hz ; medium wall filter ; power Doppler gain, 50-85%). The studies were videotaped for 5 min and serial dynamic PD static images were obtained before and 30, 60, 90, 120, 180, 240, and 300 seconds after intravenous injection of the contrast agent(Levovist 200 mg/mL at a rate of 0.2mL/sec). Images were reviewed to determine the pattern and the amount of PD signals within the tumor. These findings were also compared with findings at dynamic contrast-enhanced(n=9) and two-phase spiral CT (n=7).
Results : Unenhanced PD images showed no intratumoral Doppler signal in 12 cases(71%) and minimal dot-like or linear signals were depicted at the periphery of the tumor in five cases(29%). The most common enhancement pattern was dot-like or linear enhancement predominantly located at the periphery of the tumor(13 cases, 76%). Diffuse homogeneous enhancement was seen in one case(6%). There was no definite contrast nhancement in three cases(18%). The contrast enhancement began at 30 sec in 11 cases(65%) and at 60-120 sec in three cases(18%0. Enhancing areas began to decrease at 90-120 sec in 12 cases(60%). Centripetal fill-in pattern was identified in five cases(25%). Persistent enhancement until 300 sec was not seen in any case.
Conclusion : Peripheral linear or dot-like enhancement is the most common findings of hepatic hemangiomas at dynamic contrast-enhanced power Doppler US. However, centripetal fill-in with pesistent enhancement is usually not seen, therefore, specific diagnosis of hemangioma with this imaging technique is limited.
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