Detection of liver metastases -: Comparison of contrast -: Enhanced ultrasound using first versus second generation contrast agents

Aim: To compare detection rates for liver metastases for conventional ultrasound, US using tissue harmonic imaging (THI), echo-enhanced pulse inversion harmonic imaging using Optison(R) and Levovist(R). Method: In 73 patients with histologically proven gastrointestinal tumors spiral CF (S-CF), conventional US, US in the THI-mode, echo-enhanced ultrasound in the portal venous phase (ECIOptison) and in the liver specific late phase (ECILevovist) were performed and reviewed by blinded readers. Results: 73 patients (25 female, 48 male, age 63 +/- 11) were included. S-CT detected 158 liver metastases. Conventional US detected 117, THI 119, ECIOptison 169 and ECILevovist 166 liver metastases. Especially for small (< 2 cm) liver metastases and metastases near the diaphragm echo-enhanced ultrasound exceeded conventional US (p < 0.001). Between both echo enhancers there was no significant difference. Conclusion: Using echo enhancers increases the ultrasound detection rate significantly. Examination in the portalvenous phase using a second generation enhancer (Optison(R)) is equal to a late-phase examination using Levovist(R).