Objective: Use of new echo enhancers capable of passing the lung filter has extended the clinical applications of color power Doppler flow imaging in many diseases and appears promising in the study of neoplasm vascularization. Levovist (Shering, Berlin Germany) is an ultrasound contrast agent containing galactose microbubbles suspended in palmitic oil. The sensitivity of Levovist-enhanced color power Doppler was compared to that of standard color power Doppler and contrast-enhanced spiral computed tomography (CT) in the detection of vascular signals in hepatocellular carcinoma.
Methods: We examined 29 hepatocellular carcinoma nodules in cirrhotic livers that had appeared avascular on unenhanced color power Doppler. Color power Doppler studies were repeated with and without Levovist enhancement before (15 examinations) and/or after (23 examinations) percutaneous ablation procedures. Findings (vascularized vs nonvascularized) were compared to those obtained with contrast-enhanced spiral computed tomography (gold standard) performed no more than 24 h after each of the 38 Doppler examinations.
Results: In pretreatment studies, Levovist-enhanced power Doppler correctly revealed vascularization in 12 of 15 lesions that had appeared avascular without echo enhancement and confirmed the avascularity of one other nodule; the remaining two, which appeared avascular on contrast-enhanced Doppler, displayed vascularization on the spiral CT examination. Levovist-enhanced power Doppler was fully concordant with spiral CT findings in all of the posttreatment examinations.
Conclusion: Considering the absence of false positive results in this study, echo-enhanced color power Doppler can be considered reliable in diagnosing incomplete necrosis of hepatocellular carcinomas after percutaenous ablation. Spiral computed tomography can thus be reserved for those cases in which the enhanced power Doppler examination reveals no evidence of vascularity.