Detection of liver metastases: comparison of contrast-enhanced wide-band harmonic imaging with conventional ultrasonography.

OBJECTIVE To compare the detection rate of conventional ultrasonography and contrast-enhanced wide-band harmonic ultrasonographic imaging in the detection of small liver metastases. METHODS Consecutive patients with histologically proved gastrointestinal carcinoma liver metastases were studied. Biphasic helical computed tomography, conventional ultrasonography, and contrast-enhanced wide-band harmonic imaging were performed on all patients within a 5-day period. The biphasic helical computed tomographic scans were reviewed and interpreted by a skilled radiologist. The number of lesions and their descriptive characteristics were recorded for analysis. In addition, videotape recordings of the conventional ultrasonography and contrast-enhanced wide-band harmonic imaging were blindly reviewed, after which the number of detected lesions and their characteristics were then compared with those detected on biphasic helical computed tomography, considered the standard of reference. RESULTS Twenty-eight patients (10 female and 18 male; age range, 45-72 years) were studied. Conventional ultrasonography detected 37 (59%) of all lesions visualized by biphasic helical computed tomography. The detection rate for contrast-enhanced wide-band harmonic imaging was significantly higher (61 [97%] of 63). In our series, two 10-mm lesions near the diaphragm were not visualized by wide-band harmonic imaging. CONCLUSIONS The use of contrast-enhanced imaging techniques significantly improves the ultrasonographic detection of liver metastases. Our results achieved the sensitivity of biphasic helical computed tomography.