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 and examination 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 35 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 in the first round 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 standardised rating scale for CEUS image and examination quality assessment. Individual criteria will be grouped into broader data derived quality domains and transformed into practical assessment items and prompts. The proposed rating scale will use a three point scoring system (0="unacceptable quality", 1="acceptable quality", 3="High quality". The resulting rating tool will then be circulated among all Delphi panel members who completed all three Delphi rounds 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 images and 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.