Contrast-enhanced Ultrasound for Liver Imaging: Recent Advances

Abstract

Contrast-enhanced ultrasonography (CEUS), providing relevant informations not available with non-enhanced ultrasonography, greatly impacted the practice of liver imaging. The characterization of focal liver lesions (FLLs), is obtained in a rapid, accurate and safe way and is considered the main hepatic indication; however CEUS offers other established or emergent relevant applications. Metastases detection and assessment of response to locoregional tumor treatment are accepted applications with specific indications. Needle guidance in case of poorly or non visible target lesions at conventional ultrasound is also accepted. The early assessment of response to systemic treatment, and in particular to antiangiogenic ones, by quantification software is an emergent application. The manageability of CEUS determined also its use in the operating theatre, improving the accuracy of intraoperatory US with a significant impact on final surgical strategy. In cirrhotic patients, the role of CEUS was proven highly accurate and sensitive in the characterization of portal vein thrombosis, by identification of contrast arterial enhancement inside the thrombus, that occurs only in case of neoplastic origin. In recent years microbubbles taken up by Kupffer cells, thus possessing a "postvascular" phase, were registered as ultrasound contrast agent in Japan (Sonazoid). During the post-vascular phase tumoral tissue tend to appear as a contrast defect image due to the lack of Kupffer cells, strongly contributing to tumor staging beside characterization. Newly developed techniques, such as fusion imaging or real-time three dimensional US, in addition to other applications of CEUS, in terms of post-transplantation or cholecystitis-related complications, have been recently proposed and will be discussed.

Interaction of Kupffer Cells and Platelets Determines the Severity of Ischemia-Reperfusion Injury in Steatosis

“…Also in the steatotic liver, KC-platelet interaction and the number of KCs were strongly associated with hepatic IR injury. Therefore, there is a possibility that the degree of IR injury can be predicted before surgery, if the number of KCs in the liver can be quantified, i.e., by liver biopsy or contrast-enhanced ultrasonography with Sonazoid (Salvatore et al 2012). For clinical application, further studies will be necessary.…”

The Role of Multimodality Imaging Techniques on Differential Diagnosis of Precancerous Nodules and Hepatocellular Carcinoma

“…The introduce of Sonazoid has expanded the use of ultrasound imaging [17] .which was previously used to differentiate between HCC and benign lesions, determine the degree of HCC differentiation, evaluate efficacy after transcatheter arterial chemoembolization, and guide fineneedle aspiration. Now it also has important roles in guiding RF ablation and detecting post-surgery relapsed lesions, the clinical staging of HCC, and the selection of treatment regimens.…”

Ultrasound Examination in Detection and Characterization of Colorectal Liver Metastases

“…CEUS has been widely used in many different applications, especially in the detection and diagnosis of FLLs [28] . In many clinical trials, CEUS has shown high performance comparable to CECT and CEMRI in detection and characterization of FLLs [29][30][31] . Malignant FLLs, especially liver metastasis usually present arterial rim-like or homogeneous hyper-enhancement with "defect of enhancement" during the late phase or liver specific phase of CEUS, which makes the characterization and detection as accurate and easy as CECT [32] .…”