Occult liver nodules: their detection and characterization with CEUS

Area of Science:

• Radiology
• Hepatology
• Oncology

Background:

• Contrast-enhanced ultrasound (CEUS) is emerging as a key noninvasive diagnostic tool for hepatocellular carcinoma (HCC), comparable to CT and MRI.
• CEUS LI-RADS offers high specificity for HCC diagnosis, but its application to nodules invisible on pre-contrast ultrasound (occult nodules) is limited.
• Current guidelines recommend expert-level CEUS for occult nodules, highlighting a need to assess broader applicability.

Purpose of the Study:

• To evaluate the capability of CEUS in detecting occult liver nodules in patients at risk for HCC.
• To assess the characterization of these occult nodules using the CEUS LI-RADS algorithm.
• To determine the impact of CEUS-based characterization on clinical management decisions.

Main Methods:

• Retrospective analysis of 100 patients at risk for HCC (81 with cirrhosis) who had occult lesions identified.
• Utilized three specialized CEUS techniques: blindshot injection, portal venous phase (PVP) sweep, and on-top injection for nodule evaluation.
• Applied the CEUS LI-RADS algorithm for lesion characterization and compared findings with prior CT/MRI reports.

Main Results:

• 114 occult lesions were identified in 100 patients; 78% were initially noted on CT/MRI, while 32% were first detected by CEUS.
• CEUS LI-RADS categorized lesions as 26 LR-5, 34 LR-4, and 5 LR-M, upgrading the LI-RADS category for 48% of lesions previously reported on CT/MRI.
• CEUS facilitated treatment for 29% of occult lesions, with 5 confirmed by biopsy and 15 treated based on CEUS findings; treatment response was also assessed.

Conclusions:

• Specialized CEUS techniques enable the detection and characterization of occult liver nodules.
• The CEUS LI-RADS algorithm effectively categorizes these lesions, impacting diagnostic accuracy.
• This approach positively influences clinical management, including treatment decisions and response assessment.