Low-mechanical-index B-mode phase-inversion harmonic imaging significantly improves hepatic lesion conspicuity during...

This study compared the imaging performance of low-mechanical-index phase-inversion harmonic imaging (low-MI PIHI) with conventional contrast-enhanced ultrasonography (CEUS) during the Kupffer phase (KP) of Sonazoid-enhanced imaging for visualizing hepatic lesions, focusing on lesion conspicuity and overall image quality.

This prospective study was approved by the Institutional Review Board and included 71 patients with 72 focal liver lesions examined between February 2023 and January 2024. All patients underwent Sonazoid-enhanced CEUS. Three image sets were acquired for each lesion: baseline B-mode imaging, conventional KP imaging, and low-MI PIHI KP imaging. Two independent radiologists, blinded to clinical information, independently evaluated lesion conspicuity, border delineation, and overall image quality using a 5-point Likert scale.

Baseline B-mode imaging demonstrated the lowest lesion conspicuity scores, which improved with conventional KP imaging and were highest with low-MI PIHI KP imaging (all P<0.001). Compared with conventional KP imaging, low-MI PIHI KP imaging provided significantly higher lesion conspicuity for both reviewers (P<0.001), with the most pronounced improvement observed in hepatocellular carcinomas within cirrhotic livers, where conspicuity scores nearly doubled (P<0.001). Lesion border delineation also improved significantly for both reviewers (P<0.001). Overall image quality was consistently superior with low-MI PIHI KP imaging (P≤0.003). These advantages were particularly evident for small lesions (≤2 cm) and in cirrhotic liver backgrounds.

Low-MI PIHI KP imaging significantly enhances hepatic lesion conspicuity and margin delineation compared with conventional CEUS harmonic imaging, while also improving overall image quality. These improvements may support more confident lesion detection and facilitate image-guided procedures.