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Dynamic sonography of hepatic tumors.

OBJECTIVE
Our objectives were to propose and evaluate a dynamic sonography protocol for the characterization of hepatic tumors.


SUBJECTS AND METHODS
The subjects were 107 patients with focal liver lesions that initially had been found on conventional sonograms. The final diagnoses for the lesions were hepatocellular carcinoma in 60 patients, cholangiocellular carcinoma in six, metastatic carcinoma in 24, hemangioma in 10, and focal fat-spared region in seven. The pulse inversion harmonic imaging mode and a galactose-based contrast agent (Levovist) were used. Dynamic sonography was designed to obtain vascular-phase (composed of the arterial phase and the portal phase) images of the focal lesion and liver-parenchymal-phase images of the whole liver in a series obtained after a bolus injection of the contrast agent.


RESULTS
If the whole-tumor or mosaic enhancement patterns (arterial phase) and/or the reticular enhancement (parenchymal phase) are regarded as positive findings for hepatocellular carcinoma, the sensitivity, specificity, and positive predictive value of dynamic sonography in our study were 92%, 96%, and 96%, respectively. If a ring enhancement (arterial to portal phase) or a clear defect (parenchymal phase) or both are regarded as positive findings for cholangiocellular carcinoma or metastasis, the sensitivity, specificity, and positive predictive value were 90%, 95%, and 88%, respectively. If puddle enhancement (portal phase) is regarded as a positive finding for hemangioma, the figures for sensitivity, specificity, and positive predictive value were 60%, 100%, and 100%, respectively. Also, the tumors that showed no focal sign in the liver parenchymal phase were all benign lesions, such as hemangiomas or focal fat-spared regions.


CONCLUSION
Dynamic sonography in a protocol combining pulse inversion harmonic imaging and an IV bolus injection of the contrast agent proved to be an effective tool in characterizing liver tumors.