Application of volume navigation guided real time contrast-enhanced ultrasound for diagnosis of small malignant hepatic lesions

Abstract

Objective To evaluate whether volume navigation guided real time contrast-enhanced ultrasound (CEUS) can be performed effectively in diagnosis of small malignant hepatic lesions. Methods Fifty patients with suspected small malignant hepatic lesions was included in this study. Tumor diameters were small than 20 mm. All lesions were detected by contrast-enhanced MR imaging (MRI) but were undetectable on conventional ultrasound. LOGIQ E9 ultrasound system (GE Healthcare) equipped with volume navigation system was used to fuse CEUS and MRI images. CEUS was performed using real time contrast harmonic imaging at a low MI 0.05-0.12 with a 1.5-5.0 MHz probe. For each imaging session, a dose of 1.5-2.4 ml SonoVue was injected as a quick bolus into the antecubital vein. Results Consequently, fifty small malignant hepatic lesions in 50 patients were included in this study. The final diagnoses were confirmed by operation, percutaneous biopsy or radiological data, including 45 primary and 5 metastatic hepatic carcinomas. Image fusions were conducted successfully in all 50 lesions and the technical success rate was 100%. The average fusion time was (9.1±0.5) min. The detection rate of small malignant hepatic lesions using CEUS/MRI imaging fusion (96.0%, 48/50) was significantly higher than that of conventional CEUS (30.0%, 15/50) (Z=1.73, P<0.05). After injection of SonoVue, 46 (92.0%, 46/50) small malignant hepatic lesions displayed rapid wash-in pattern in the arterial phase of CEUS/MRI imaging fusion, and 4 lesions (8.0%, 4/50) showed synchronous enhancement. In the portal venous phase, 28 (56.0%, 28/50) lesions showed iso-enhancement comparing to the surrounding liver parenchyma. CEUS/MRI imaging fusion detected 48 lesions (96.0%, 48/50). After artificial pleural effusion, another 2 nodules were clearly detected. In our current research, the detection rate and diagnostic accuracy of CEUS/MRI imaging fusion were 100%. Conclusion Imaging fusion combining CEUS with MRI is a promising technique to improve the detection rate and accurate diagnosis of small malignant hepatic lesions. Key words: Liver neoplasms; Ultrasonography; Contrast media; Magnetic resonance imaging