Intraoperative high resolution linear contrast enhanced ultrasound (IOUS) for detection of microvascularization of malignant liver lesions before surgery or radiofrequeny ablation

Abstract

Objective: The aim of this study was to evaluate the value of linear contrast enhanced intraoperative ultrasound (CE-IOUS) to improve detection of malign liver tumors lesions before surgery or radiofrequency ablation (RFA). Materials and Methods: 50 patients were included for surgery of malignant liver tumors (mean age 61 years (19–80); male n = 35, female n = 15), suffering from HCC (n = 15), colorectal liver-metastasis (n = 28), CCC (n = 2) or other malign liver lesions (n = 5). Preoperative CE-CT (n = 38), CE-MRI (n = 23) or PET-CT (n = 8) confirmed hepatic tumor manifestation. Before undergoing surgery, intraoperative conventional (IOUS) as well as CE-IOUS were performed by one experienced examiner in all cases using multifrequency linear probes (6–9 MHz, 6–15 MHz; LOGIQ E9; GE Healthcare, Milwaukee, WI, USA). CE-IOUS was performed after bolus injection of 5 ml up to 15 ml SonoVue^® (Bracco Imaging SpA, Milan, Italy). Digitally stored images of CE-IOUS were compared with fundamental B-Scan and preoperative imaging (CE-CT, CE-MRI and PET-CET). Results: In 28 of 50 patients (56%), additional lesions were found using CE-IOUS (mean tumor size 8 mm, range 4–12 mm). This resulted in a change of surgical strategy or the intraoperative application of RFA in 27 patients (54%). Modification of therapy due to additionally found liver lesions was statistically significant (p < 0.05). Comparing conventional IOUS and CE-IOUS, 14 additional lesions in 10 patients were seen by CE-IOUS. All lesions seen in B-scan could also be detected with CE-IOUS. Summary: This is the first study using contrast-enhanced ultrasound with high resolution linear probes for intraoperative detection of malignant liver lesions. Compared to preoperative imaging and also conventional IOUS more than 50% additional lesions were found leading to therapeutic consequences of patients. A recently started prospective study has to show whether these changes in the surgical or interventional therapy will influence morbidity, mortality and especially the recurrence rate.