Role of gray-scale contrast enhanced ultrasound in diagnosis of liver metastasis

Objective To investigate the perfusion and echogenicity of liver metastasis using contrast tuned imaging and to discuss the role of gray-scale contrast-enhanced ultrasonography (CEUS) in the diagnosis of liver metastasis in comparison with non-enhanced ultrasound (US) and enhanced CT. Methods(Fifty-three) patients with known malignancies and suspicious liver metastasis by conventional US were performed contrast tuned imaging (CnTI) real time gray scale ultrasound examination,and 49 patients were found focal liver lesions by enhanced CT. The perfusion patterns of liver metastasis were evaluated. The sizes, numbers of lesions found during CEUS were compared with those of conventional US and CT. Results(In 53) patients, 131 lesions in liver were found by US, while 193 liver metastasis were confirmed by CEUS in 51 patients. Sixty-two more lesions were found in 22 patients by CEUS, compared to CT, 46 more lesions were found in 21 patients. The perfusion patterns of 109 major investigated lesions were in four types: (72.5)% (79 lesions) enhanced quickly in rim-like and quickly washed out with different degree in portal phase or parenchymal phase; (15.6)% (17 lesions) bolus-enhanced quickly in arterial phase and quickly washed out in portal phase or parenchymal phase; (8.2)%(9 lesions) presented no enhancement in arterial to parenchyma phase; (3.7)% (4 lesions) enhanced postpone in portal phase or simultaneously with the liver, and slightly washed out in late phase. Conclusions The perfusion patterns of liver metastasis in gray-scale CEUS, especially the early detection of small and minute liver metastasis lesions are useful for stage diagnosis and treatment methods′ selection of malignance patients.