Three-dimensional contrast-enhanced sonography of vascular patterns of focal liver tumors: pilot study of visualization methods.

ABSTRACT

OBJECTIVE: We investigated visualization methods of 3D sonography with a perflubutane-based contrast agent in the imaging evaluation of vascular patterns of focal liver tumors. MATERIALS AND METHODS: Eighty-four patients with focal liver tumors underwent automatic scanning with 3D sonography 20-60 seconds after administration of a perflubutane contrast agent. The confirmed final diagnoses were 50 hepatocellular carcinomas, 20 metastatic lesions, nine hemangiomas, and five cases of focal nodular hyperplasia. Tomographic sonographic images reconstructed in 3D parallel slices and rendered sonographic images resembling angiograms were reviewed by two readers. RESULTS: Sonographic angiograms rendered by maximum intensity of gray values in surface smooth mode showed tumor vessels and early tumor enhancement. The average intensity of gray values with surface texture mode showed unenhanced areas within tumors. Interobserver agreement for classifying enhancement patterns with both tomographic sonography and sonographic angiography was excellent (kappa=0.84). The main pattern, intratumoral vessels with early homogeneous or heterogeneous tumor enhancement, had a sensitivity of 97% (average of both readers), specificity of 94%, and positive predictive value (PPV) of 96% for hepatocellular carcinomas. The presence of tumor vessels with early peripheral ringlike tumor enhancement had a sensitivity of 90%, specificity of 95%, and PPV of 86% for metastatic lesions. Peripheral nodular enhancement had a sensitivity of 84%, specificity of 99%, and PPV of 89% for hemangioma. The presence of spoke-wheel arteries with early tumor enhancement had a sensitivity of 80%, specificity of 100%, and PPV of 100% for focal nodular hyperplasia. CONCLUSION: Three-dimensional sonography with a perflubutane-based contrast agent is useful in the evaluation of vascular patterns of focal liver tumors.