Detection and characterization of small superficially located focal liver lesions by contrast-enhanced ultrasound with high frequency transducers

Aim: To evaluate the benefits of contrast-enhanced ultrasound (CEUS) with high frequency transducers in the detection and characterization of small superficially located focal liver lesions (FLLs).Material and methods: From January 2015 to October 2016, 27 superficial FLLs detected by MRI were examined, first with the low frequency convex transducer (1-5 MHz) and afterwards with a high frequency transducer (7.5-12 MHz). High frequency dynamic CEUS was performed after a bolus injection of 2.4 ml SonoVue®. FLLs were confirmed by histopathology after surgery (n=18) or ultrasound guided 18-gauge core-needle biopsy (n=8), or by MRI follow-up (n =1).Results: The mean diameter of FLLs was 10.5±3.1 mm, and meandepth was 6.2±5.3 mm. While using a high frequency transducerthe detection rate of FLLs (100%, 27/27) was significantly higher than low frequency transducer (25.9%, 7/27) (p<0.05). The overall sensitivity, specificity and diagnostic accuracy were significantly improved by CEUS with a high frequency transducer (sensitivity 88.9%; specificity 92.6%; accuracy 96.2%).Conclusion: Combining CEUS with the performance of high-frequency transducers is a promising technique to improve the detection and accurate diagnosis of small and superficial FLLs appearing indistinctive on BMUS.