The role of contrast-enhanced sonography of focal liver lesions before percutaneous biopsy.

OBJECTIVE: The objective of our study was to evaluate the clinical utility of performing contrast-enhanced sonography before percutaneous biopsy of focal liver lesions.

SUBJECTS AND METHODS: One hundred eighty-six patients with focal liver lesions detected on either sonography or contrast-enhanced CT were randomly divided into two groups: a group who underwent contrast-enhanced sonography and another who underwent unenhanced sonography. The contrast-enhanced sonography group (79 patients, 129 lesions) underwent SonoVue-enhanced sonography before biopsy, and the unenhanced sonography group (107 patients, 143 lesions) did not undergo contrast-enhanced sonography before biopsy. Conventional sonography was used in all patients to guide the biopsy procedures. The pathologic diagnosis was considered definitive and final if the biopsy result was malignant. If the initial biopsy result was benign or negative for malignancy, then the result was either confirmed or denied on the basis of contrast-enhanced CT, MRI, angiography, serum alpha-fetoprotein level, or clinical follow-up over a period of 6 months. In some patients with suspected malignancy, biopsy was repeated when considered necessary during the follow-up. The diagnostic accuracy of the initial biopsy was defined as the percentage of the total number of lesions that were correctly diagnosed at the initial biopsy. The difference in diagnostic accuracy between the two groups was analyzed to evaluate the value of performing contrast-enhanced sonography before biopsy.

RESULTS: Of the 129 lesions in the contrast-enhanced sonography group, 28 (21.7%) were benign and 101 (78.3%) were malignant. Of the 143 lesions in the unenhanced sonography group, 36 (25.2%) were benign and 107 (74.8%) were malignant. There was no significant difference in the distribution of malignant and benign lesions in these two groups (p > 0.05). There was no statistically significant difference in the distribution of lesions by size between the contrast-enhanced and unenhanced sonography groups (chi(2) = 0.619, p > 0.05). The diagnostic accuracy of the initial biopsy was significantly higher in the contrast-enhanced sonography group than in the unenhanced sonography group (95.3% vs 87.4%, respectively; p < 0.05). The diagnostic accuracy of the initial biopsy for malignant lesions < or = 2.0 cm was also significantly higher in the contrast-enhanced sonography group than in the unenhanced sonography group (97.1% vs 78.8%, respectively; p < 0.05). No major complications occurred in our study except one case of pneumothorax in the unenhanced sonography group.

CONCLUSION: Contrast-enhanced sonography before percutaneous focal liver lesion biopsy improved the diagnostic accuracy of the procedure by providing important intralesional information for differentiating viable, denaturalized, or necrotic tissue; consequently, by providing more accurate information about the site of biopsy even in lesions < or = 2.0 cm, contrast-enhanced sonography before biopsy reduced the number of puncture attempts.