Contrast-enhanced ultrasound (CEUS) performed before percutaneous biopsy of focal liver lesions can improve the diagnostic accuracy of the procedure, according to research published in the September issue of the American Journal of Roentgenology.
"Having the information yielded by contrast-enhanced sonography performed before biopsy procedures using conventional sonography guidance can significantly decrease the false-negative rate for malignant lesion," wrote a research team led by Wei Wu of Peking University in Beijing, China (AJR, September 2006, Vol. 187:3, pp. 752-761).
The researchers studied 186 patients with focal liver lesions detected on either sonography or contrast CT. Of the 186 patients, 79 received contrast-enhanced sonography using SonoVue (Bracco, Milan, Italy) and either a Technos DU6 or DU8 sonography system (Esaote, Genoa, Italy), while 107 underwent unenhanced sonography. Conventional sonography guided the biopsy procedures in all cases.
Of the 129 lesions in the contrast-enhanced sonography group, 28 (21.7%) were benign and 101 (78.3%) were malignant. Thirty-six (25.2%) of the 143 lesions in the unenhanced sonography group were benign and 107 (74.8%) were malignant. The difference in the distribution of malignant and benign lesions in the two groups was not significant (p > 0.05); there was also no statistically significant difference in the distribution of lesions by size between the contrast-enhanced and unenhanced sonography groups (x²= 0.619, p > 0.05).
The contrast-enhanced sonography group produced the correct diagnosis in 27 of 28 (96.4%) benign lesions and 96 of 101 (95%) malignant lesions for an overall diagnostic accuracy of 95.3% in the initial biopsy. The unenhanced sonography group led to a correct diagnosis in 33 of 36 (91.7%) benign lesions and 92 of 107 (86%) malignant lesions for an overall accuracy of 87.4%. The difference between the groups was statistically significant (p < 0.05).
For malignant lesions 2.0 cm or smaller, the diagnostic accuracy of the initial biopsy was 97.1%, significantly higher than the 78.8% turned in by the unenhanced sonography group (p < 0.05). However, there was no statistically significant difference in the diagnostic accuracy of benign lesions between the contrast-enhanced sonography group and the unenhanced sonography group (p > 0.05), according to the authors.
The study showed that contrast-enhanced sonography can provide the biopsy operators with important information about malignant lesions, including lesions smaller than 1 cm, according to the researchers.
"Our results also indicated that operators' knowledge of the information from contrast-enhanced sonography before biopsy resulted in a reduced number of puncture attempts during the procedure," they wrote. "A single puncture attempt was successful in 14.0% of the patients in the contrast-enhanced sonography group compared with a successful single puncture in 4.9% of the patients who did not undergo contrast-enhanced sonography."
No major complications occurred in the study, except for one case of pneumothorax in the unenhanced sonography group.
"Contrast-enhanced sonography can be used to localize the site for biopsy more accurately by differentiating areas of viable tumor from denaturalization or necrosis," the authors concluded. "In addition, contrast-enhanced sonography can be used to detect tumors ≤ 2.0 cm, and its use in this setting reduces the number of puncture attempts and significantly increases the success rate of biopsy."
By Erik L. Ridley
AuntMinnie.com staff writer
August 25, 2006
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