[Application of contrast-enhanced ultrasound to increase the diagnostic rate of liver tumor by biopsy].

Objective: To evaluate the clinical utility of contrast-enhanced ultrasound (CEUS) in percutaneous liver biopsy of focal liver lesions.

Methods: Two hundred and eleven patients with unidentified space occupying lesions in liver, 112 males and 74 females, aged 52 (16-78), were randomly divided into 2 groups: CEUS group in which 96 cases with 149 lesions underwent liver biopsy with 21-18 gauge needles directed by real time grey CEUS, and routine ultrasound (US) group in which 115 patients with 153 lesions underwent biopsy guided by conventional ultrasonography. There was no significant difference in the size of lesions between these 2 groups. There were 75 minute malignant lesions with the size of < or = 2.0 cm (24.8%) in 67 patients, 12.9% in the CEUS group and 11.9% in the US group. Obtainment of adequate specimen for pathological examination meant successful biopsy. Definite diagnosis was made by the combination of the results of pathological examination, CEUS, CT, MRI, angiography, serum alpha-fetoprotein, and 3 to 6-month follow-up.

Results: The proportion of no more than 2 puncture attempts in the CEUS group was 33/19, significantly higher than that in the US group (8/153, P = 0.0007). The biopsy success rate of the CEUS group was 98.7%, significantly higher than that of the US group (91.5%, P = 0.0096). The accurate diagnosis rate of the CEUS group was 96.0%, significantly higher than that of the US group (87.6%, P = 0.0165). The accurate diagnosis rate of malignant lesions with the size of < or = 2.0 cm in the CEUS group was 97.4%, significantly higher than that in the US group (80.6%, P = 0.0473). Among the 112 confirmed malignant lesions in the US group 15 had been diagnosed as benign by pathological examination of the biopsy specimens with a false negative rate of 13.4%. The relevant patients underwent CEUS-guided biopsy again and 14 of the 15 lesions were confirmed as malignant finally and the size of 6 of the 14 lesions was < or = 2.0 cm. Except for one case of pneumothorax in the US group no major complication occurred.

Conclusion: Biopsy guided by CEUS is more accurate in location and diagnosis of malignant lesions and minute tumors in the liver, thus increasing the success rate of biopsy and the confirmed diagnosis rate of malignant lesions.