International Delphi Study to Develop Standardized Quality Criteria and a Rating Tool for Liver CEUS Image Quality Assessment

This study aims to establish international consensus-based quality criteria for contrast-enhanced ultrasound (CEUS) examinations of the liver and to develop a standardized tool for assessing CEUS image quality. CEUS is an established imaging technique used in clinical practice for the characterization and assessment of focal liver lesions and other liver abnormalities. Despite its increasing use, there are currently no universally accepted or validated standards for evaluating the quality and reproducibility of CEUS examinations. The primary objective of this project is therefore to identify robust and clinically relevant quality indicators for liver CEUS examinations through an international Delphi consensus process. The study focuses specifically on CEUS examinations performed in adult patients using the ultrasound contrast agent SonoVue®. The project is divided into two work packages (WP). In Work Package 1 (WP1), the study team will first conduct a structured review of the available literature and discuss potential CEUS quality criteria within the research group. Based on this process, an initial catalogue of quality indicators relating to technical, procedural, and imaging characteristics relevant to liver CEUS examinations will be developed. These proposed criteria will subsequently be evaluated through a multi-round Delphi process involving an international and interdisciplinary panel of experienced CEUS users and experts. A minimum of 20 panellists will participate across all Delphi rounds. Participants will rate their level of agreement with each proposed quality criterion using a 7-point Likert scale and may suggest additional criteria where appropriate. Newly proposed criteria supported by more than 10% of participants will be included in subsequent Delphi rounds. During each round, panellists will receive anonymised feedback summarising the responses of the group and will be invited to re-evaluate the relevance of the proposed criteria. This iterative process will continue for at least three rounds or until predefined consensus criteria are achieved. Consensus will be defined as at least 70% agreement with a rating of 6 or higher on the Likert scale. In Work Package 2 (WP2), the consensus-based quality criteria identified in WP1 will be operationalised into a comprehensive and standardized rating scale for CEUS image quality assessment. Individual criteria will be grouped into broader domains and transformed into practical assessment items and prompts. The resulting rating tool will then be circulated among all Delphi panel members for final review and feedback to ensure clarity, applicability, and international usability. The overall goal of this study is to improve standardization, quality assurance, and reproducibility in liver CEUS examinations. The developed consensus criteria and rating scale may support clinical practice, future research studies, multicentre collaborations, and educational initiatives by enabling more consistent evaluation of CEUS image quality across institutions and countries.

Inclusion Criteria: * At least 6 years of active experience in ultrasound diagnostics in internal medicine, radiology, or a related clinical field * Independent performance of at least 5,000 ultrasound examinations Participation in structured CEUS training * Performance of at least 800 ultrasound examinations per year in routine clinical practice * Either: at least 100 independently performed CEUS examinations per year or more than 700 CEUS examinations in total * Regular participation in ultrasound-related meetings, case reviews, or quality assurance activities within their institution * Scientific involvement in CEUS, demonstrated by at least one peer-reviewed publication and/or active engagement in CEUS education or training * Signing the consent form of the participants Exclusion Criteria: * Failure to meet the inclusion criteria