Analysis of Liver Tumors Using Preoperative and Intraoperative Contrast-Enhanced Ultrasound (CEUS/IOCEUS) by Radiologists in Comparison to Magnetic Resonance Imaging and Histopathology

Abstract

ABSTR AC TPurpose To evaluate the diagnostic significance of preoperatively and intraoperatively performed contrast-enhanced ultrasound (CEUS/IOCEUS) in the diagnosis of liver tumors in comparison to magnetic resonance imaging (MRI) and histopathology. Materials and Methods Retrospective analysis of 70/317patients who underwent surgery for liver tumors between January 2012 and October 2015. Findings of CEUS and IO-CEUS were compared to MRI. CEUS and IOCEUS were performed using multifrequency linear probes (1 -5, 6 -15 MHz) after bolus injection of 1 -5 ml sulfur hexafluoride microbubbles. The histopathology after surgical resection, MRI morphology (T1, T2, VIBE, diffusion sequences) and wash-in/wash-out kinetics of CEUS were evaluated.Results In 70 analyzed patient cases, 64 malignant liver lesions could be detected. 6 patients had benign liver lesions. Among the 64 malignant lesions, there were 28 metastases, 24 hepatocellular carcinomas (HCC), 9 cholangiocellular carcinomas (CCC) and 3 gallbladder carcinomas. 2 of the 6 benign liver lesions were hemangiomas, 2 were adenomas, 1 was an FNH and 1 was a complicated cyst. There was no significant difference when determining the lesion's malignancy/ benignity (p = 1.000). Furthermore, there was no statistical significance between preoperative CEUS and MRI regarding the general differential diagnosis of a tumor (p = 0.210) and the differential diagnosis classification between HCCs (p = 0.453) and metastases (p = 0.250). There was no statistical significance in tumor size (10 mm -151 mm; mean 49 mm SD +/-31 mm) and location (tumor size p = 0.579; allocation to liver lobes p = 0.132; segment diagnosis p = 0.121) between preoperatively performed CEUS and MRI. The combination of preoperative MRI and CEUS for lesion detection showed significant differences compared to CEUS or MRI only (p < 0.001 for CEUS; p = 0.004 for MRI). IOCEUS offered the substantial advantage of locating additional liver lesions (p = 0.004 compared to preoperative MRI, p = 0.002 compared to preoperative CEUS). In 10/37 cases (27 %) IOCEUS could locate further liver lesions which had not been identified during CEUS and/or MRI preoperatively, so that operative therapy was adapted accordingly and resection was extended if necessary. Schlussfolgerung CEUS erweist sich in der präoperativen Diagnostik von Lebertumoren als eine dynamische Bildgebung mit hoher diagnostischer Aussagekraft über die Tumormikrovaskularisierung und ist somit hilfreich zur Bewertung von Tumorentität und Tumorgröße von Lebertumoren. Intraoperativ kommt CEUS eine wesentliche Bedeutung in der operativen Therapieentscheidung zu.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver – Update 2020 – WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

“…Several studies using different UCAs have shown that contrast enhanced intraoperative US (CE-IOUS) enhances tumor detection and allows to assess the region for resection, where previously a pre-treatment colorectal liver metastasis was present but has re-gressed [175][176][177][178][179][180][181][182]. In particular it has proven valuable for the differential diagnosis between HCC and dysplastic nodule, using both SonoVue [176] and Sonazoid [180].…”

Evaluation of Contrast-Enhanced Intraoperative Ultrasound in the Detection and Management of Liver Lesions in Patients with Hepatocellular Carcinoma

“…In 2004, Sahani et al [26] claimed that MRI is as sensitive as IOUS in depicting hepatic lesions before hepatic resection (86.7% and 94.3%, respectively). Moreover, Huf et al [27] reported no statistical significance of CEUS and MRI regarding the general differential diagnosis for hepatic tumors. In this study, we highlighted the importance of the presence of interventional radiologist with CE-IOUS and RFA experience during liver resection procedures, in order to perform intraoperative ultrasound, able to ensure optimized liver surgery and able to provide an alternative treatment for unexpected new liver lesions unsuitable for resection.…”

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization

“…In patients with a history of primary malignancy, noncontrast MRI can differentiate between malignant and benign lesions with accuracy of 71% [47]. The accuracy increases by between 83% and 91% with the addition of dynamic postcontrast sequences and further increases to 94% with addition of HBP [47,48]. In patients with a history of colon cancer, the lesion characterization on contrast-enhanced MRI is correct in 89% of cases [41].…”

“…Depending on the appearance of the lesion on the initial US, CEUS may be performed for lesion characterization. CEUS can differentiate between malignant and benign lesions in 90% of lesions [48]. Diagnostic accuracy of CEUS for metastases is 83% compared with 76% for MRI with extracellular contrast agent [35].…”