Prospective multicenter trial evaluating a novel method of characterizing focal liver lesions using contrast-enhanced sonography

OBJECTIVE. The purpose of this study was to assess the clinical value and potential impact of SonoVue-enhanced sonography in the characterization of focal liver lesions. SUBJECTS AND METHODS. This study included 127 patients with 82 malignant and 52 benign lesions in the liver. Contrast-enhanced sonography was performed using nonlinear imaging modes at low mechanical index (0.1-0.3) to enable real-time visualization of arterial, portal, and late-phase enhancement. Digital recordings of unenhanced sonography and contrast-enhanced sonography were reviewed by on-site investigators and two off-site blinded interpreters. The final diagnosis was based on consensus interpreting of all examinations by another two expert observers with access to CT, MRI, and histologic data; the diagnostic accuracy of contrast-enhanced sonography in identifying the lesion as benign, malignant, or indeterminate and as actual tumor type was compared with baseline sonography. RESULTS. For on-site investigators, contrast-enhanced sonography reduced the number of indeterminate diagnoses by 67% and improved the sensitivity and specificity to 90.2% and 80.8%, respectively (p < 0.001). For off-site interpreters, contrast-enhanced sonography reduced the number of indeterminate diagnoses by 51-56% (p < 0.001); significantly improved sensitivity and specificity to 90.8-95.4% and 83.7-89.8%, respectively (p < 0.001); eliminated observers' variability (kappa coefficient: 0.66-0.77); and showed no significant difference in all comparisons in the analysis of lesions measuring less than 1.5 cm, 1.5-2.5 cm, and all sizes combined. Contrast-enhanced sonography did not rely on availability of clinical history to enable the diagnoses, and it reduced the need for further imaging investigations 23.7% to 90.4%. CONCLUSION. Contrast-enhanced sonography improves the characterization of focal liver lesions and may limit the need for further investigations.