Contrast enhancement for ultrasound-guided interventions: when to use it and what to expect?

An exploration of radiological signs in post-intervention liver complications

The advent and progression of radiological techniques in the past few decades have revolutionized the diagnostic and therapeutic landscape for liver diseases. These minimally invasive interventions, ranging from biopsies to complex therapeutic procedures like transjugular intrahepatic portosystemic shunt placement and transarterial embolization, offer substantial benefits for the treatment of patients with liver diseases. They provide accurate tissue diagnosis, allow real-time visualization, and render targeted treatment for hepatic lesions with enhanced precision. Despite their advantages, these procedures are not without risks, with the potential for complications that can significantly impact patient outcomes. It is imperative for radiologists to recognize the signs of these complications promptly to mitigate further health deterioration. Ultrasound, CT, and MRI are widely utilized examinations for monitoring the complications. This article presents an overarching review of the most commonly encountered hepatobiliary complications post-radiological interventions, emphasizing their imaging characteristics to improve patient post-procedure management.

Contrast-enhanced ultrasound fundamentals: the pharmacodynamics and pharmacokinetics of contrast. Basics of contrast-enhanced ultrasound imaging

Contrast-enhanced ultrasound (CEUS) is a medical imaging technique that offers multiple advantages over other modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). These advantages include portability, no ionising radiation and no renal toxicity, with the great advantage of real-time imaging. CEUS has numerous established applications for the study of different pathologies, both intravenous and intracavitary administration. The contrast used is different in composition and function from CT or MRI contrast. It is a purely intravascular contrast and, therefore, the enhancement of the lesions may have some differences with respect to CT or MRI in the equilibrium phase. Ultrasound contrast has a very good safety profile, with infrequent, generally mild and immediate adverse reactions in intravascular use and no adverse reactions reported in intracavitary use. It is important to know the basics of contrast-enhanced ultrasound, the different ways to optimise the image and the different artefacts.

Usefulness of contrast-enhanced ultrasound-guided biopsy for suspected viable hepatocellular carcinoma after treatment: a single-arm prospective study

PURPOSE

The utility of contrast-enhanced ultrasound (CEUS)-guided liver biopsy in patients with treated hepatocellular carcinoma (HCC) was evaluated.

METHODS

This study prospectively enrolled 36 patients (mean age±standard deviation [SD], 65.3±9.2 years; 31 men) who underwent CEUS-guided biopsy for treated HCC between September 2020 and April 2022, constituting the CEUS group. An additional 60 patients (mean age±SD, 60.7±12.3 years; 50 men) who underwent B-mode image-guided biopsy for treated HCC between January 2017 and December 2018 were retrospectively enrolled in the B-mode, or control, group. Biopsy success rates were compared between CEUS and B-mode groups using the chi-square test.

RESULTS

The biopsy success rate in the CEUS group was 88.9% (32 of 36 patients), which was significantly higher than the 70.0% (42 of 60 patients) observed in the B-mode group (P=0.044). No significant difference was found between CEUS and B-mode groups in the size of the lesions targeted for biopsy (mean±SD, 3.8±2.3 cm vs. 3.7±3.3 cm, respectively; P=0.332). For both the whole tumor and the viable tumor, conspicuity scores were significantly higher on CEUS than on grayscale ultrasound in the CEUS group (whole tumor: 2.7±0.5 vs. 1.8±0.9, P<0.001; viable tumor: 2.6±0.7 vs. 1.4±0.8, P<0.001). Relative to non-diagnostic results, diagnostic results more frequently exhibited a late mild washout pattern (87.5% [28 of 32] vs. 25.0% [1 of 4], P=0.004). No significant difference in the arterial enhancement pattern was noted between these subgroups (P=0.415).

CONCLUSION

By increasing the viable-tumor conspicuity, CEUS-guided biopsy is useful for confirmative histopathologic diagnosis in patients with treated HCC.

Refining Liver Biopsy in Hepatocellular Carcinoma: An In-Depth Exploration of Shifting Diagnostic and Therapeutic Applications

The field of hepatocellular carcinoma (HCC) has faced significant change on multiple levels in the past few years. The increasing emphasis on the various HCC phenotypes and the emergence of novel, specific therapies have slowly paved the way for a personalized approach to primary liver cancer. In this light, the role of percutaneous liver biopsy of focal lesions has shifted from a purely confirmatory method to a technique capable of providing an in-depth characterization of any nodule. Cancer subtype, gene expression, the mutational profile, and tissue biomarkers might soon become widely available through biopsy. However, indications, expectations, and techniques might suffer changes as the aim of the biopsy evolves from providing minimal proof of the disease to high-quality specimens for extensive analysis. Consequently, a revamped position of tissue biopsy is expected in HCC, following the reign of non-invasive imaging-only diagnosis. Moreover, given the advances in techniques that have recently reached the spotlight, such as liquid biopsy, concomitant use of all the available methods might gather just enough data to improve therapy selection and, ultimately, outcomes. The current review aims to discuss the changing role of liver biopsy and provide an evidence-based rationale for its use in the era of precision medicine in HCC.

No-Touch Radiofrequency Ablation for Early Hepatocellular Carcinoma: 2023 Korean Society of Image-Guided Tumor Ablation Guidelines

Radiofrequency ablation (RFA) has been widely used to manage hepatocellular carcinomas (HCCs) equal to or smaller than 3 cm. No-touch RFA has gained attention and has recently been implemented in local ablation therapy for HCCs, despite its technical complexity, as it provides improved local tumor control compared to conventional tumor-puncturing RFA. This article presents the practice guidelines for performing no-touch RFA for HCCs, which have been endorsed by the Korean Society of Image-Guided Tumor Ablation (KSITA). The guidelines are primarily designed to assist interventional oncologists and address the limitations of conventional tumor-puncturing RFA with describing the fundamental principles, various energy delivery methods, and clinical outcomes of no-touch RFA. The clinical outcomes include technical feasibility, local tumor progression rates, survival outcomes, and potential complications.

Multimodality Imaging Assessment of Desmoid Tumors: The Great Mime in the Era of Multidisciplinary Teams

Desmoid tumors (DTs), also known as desmoid fibromatosis or aggressive fibromatosis, are rare, locally invasive, non-metastatic soft tissue tumors. Although histological results represent the gold standard diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. Although histological analysis represents the gold standard for diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. DTs represent a challenge for the radiologist, being able to mimic different pathological conditions. A proper diagnosis is required to establish an adequate therapeutic approach. Multimodality imaging, including ultrasound (US), computed tomography (CT) and Magnetic Resonance Imaging (MRI), should be preferred. Different imaging techniques can also guide minimally invasive treatments and monitor their effectiveness. The purpose of this review is to describe the state-of-the-art multidisciplinary imaging of DTs; and its role in patient management.