Contrast-enhanced multiphase dynamic ultrasonography for the characterization of liver tumors.

Purpose: The purpose of the study was to introduce our protocol for contrast-enhanced multiphase dynamic ultrasonography (US) and examine the effectiveness of this method for characterizing liver tumors.

Methods: The subjects were 142 patients with liver tumors. The final diagnoses were 58 hepatocellular carcinomas (HCCs), 4 cholangiocellular carcinomas (CCCs), 14 metastases, 29 hemangiomas, 6 cases of focal nodular hyperplasia (FNH), and 31 other benign lesions. The contrast agent used was Levovist. A wide-band pulse inversion harmonic imaging mode was employed. Multiphase dynamic US was achieved by changing the sound transmission interval automatically from 0.3 s to 15.0 s according to a preset menu. Early arterial-phase images were observed at the short interval, and an equilibrium-phase image was observed at the longest interval. After a series of vascular images, a postvascular liver parenchymal image was obtained. Based on previously published criteria, the most compatible diagnosis was noted. The accuracy of this multiphase dynamic US technique for diagnosing focal liver lesions was examined by comparing our results with the final diagnosis based on a prospective study.

Results: The overall accuracy of all 142 cases was 93.7%. The sensitivity, specificity, and positive predictive value were, respectively, 100%, 92.9%, and 90.6% for HCC; 88.9%, 97.6%, and 84.2% for metastasis or CCC; 89.7%, 100%, and 100% for hemangioma; and 83.3%, 100%, and 100% for FNH.

Conclusion: Contrast-enhanced multiphase dynamic US is a highly accurate, safe diagnostic tool for characterizing liver tumors.