Comparative efficacy of contrast-enhanced ultrasound versus B-mode ultrasound in the diagnosis and monitoring of hepatic abscesses.

Purpose: This study aimed to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in diagnosing and monitoring hepatic abscesses (HA).

Material and methods: This retrospective study included 29 patients (9 females, 20 males) with 64 HA. Computed tomography (CT) served as the diagnostic benchmark, compared with CEUS and B-mode ultrasound (B-mode). Two radiologists assessed the presence, size, and characteristics of the HA.

Results: The contrast enhancement pattern on CEUS matched post-contrast CT. Lesion size detected by CEUS ranged from 1.16 cm to 15.33 cm (median 5.74 cm). CT classified lesions into four types: I (tumor-like) - 2, II (honeycomb) - 5, III (lacunar) - 23, IV (cystic-like) - 34. CEUS fully agreed with these classifications. B-mode missed two type I lesions. For type III abscesses, agreement with CEUS was perfect (κ = 1, 100%), and moderate with B-mode (κ = 0.50, 79.7%). For type IV abscesses, agreement with CEUS was perfect (κ = 1, 100%), and high with B-mode (κ = 0.88, 93.75%). Pus enhancement remained stable (± 15 dB), while the abscess pouch background varied (± 11 dB to ± 6 dB). The Mann-Whitney U test confirmed these observations (arterial: p = 1.02e-14, portal: p = 3.79e-12, late venous: p = 4.53e-13). No significant difference in enhancement values was found based on abscess size (> 4 cm vs. < 4 cm).

Conclusions: CEUS is superior to B-mode for diagnosing and monitoring HA, offering clearer views of the abscess pouch, septa, and liver parenchyma. The purulent part lacks contrast, allowing accurate assessment. CEUS can replace CT for monitoring and aid in patient selection for percutaneous intervention.