The diagnostic value of focal liver lesion (≤2 cm) undetectable on conventional ultrasound by image fusion with contrast-enhanced ultrasound

Objective To evaluate and explore the diagnostic value of focal liver lesion (FLL) (≤2 cm) undetectable on conventional ultrasound by image fusion with contrast-enhanced ultrasound(CEUS). Methods A total of 50 patients with 65 lesions(≤2 cm) were enrolled. All lesions were undetectable on conventional ultrasound but showed clearly in CT/MRI images. Ultrasound-CT/MRI image fusion with CEUS was performed, and the nodule detection rate and enhancement perfusion mode were analyzed. Results All the 50 patients were matched successfully, 56 lesions (86.2%) were detected by image fusion combined with CEUS, among which 27 lesions (41.5%) were significantly different from surrounding parenchyma on conventional ultrasound, 54 lesions(83.1%) showed different enhancement from the surrounding parenchyma on CEUS. There were 46 lesions that were eventually diagnosed by surgical pathology or clinical comprehensive diagnosis. The diagnostic accuracy of image fusion with CEUS was 91.3% (42/46). According to different groups of MRI matching sequences, the detection rates of T2 sequence group and enhanced sequence group were 87.5% (28/32) and 91.3% (21/23), respectively, there was no statistically significant difference between the two groups (P=0.686). Conclusions CT/MRI image fusion combined with CEUS has high detection rate and diagnosis accuracy for small FLL undetectable on conventional ultrasound. Key words: Contrast-enhanced ultrasound; Image fusion; Focal liver lesion