A Multicenter Comparative Study Evaluating the Impact of an AI-Assisted Chest CT Reporting System on Real-world Radiologist Performance: The DOUBLE-ACE Study

Inclusion Criteria

The study participants include both the radiologists whose performance is evaluated and the chest CT scans they interpret. Eligibility criteria are defined for both. 1\. Inclusion Criteria 1.1 For Radiologists 1. Board-certified radiologists specializing in or routinely performing thoracic imaging. 2. Employed at one of the participating study centers for the entire duration of both the without-AI and with-AI study periods. 3. Interpreted a minimum of eligible chest CT scans (e.g., \> 50 scans) during both the without-AI and with-AI data collection periods. 1.2 For Chest CT Scans 1. Non-contrast chest CT examinations performed for any clinical indication. 2. Scans completed and finalized during the defined with-AI or without-AI study periods. 3. Patient age 18 years or older at the time of the scan. 2\. Exclusion Criteria 2.1 For Radiologists: 1. Radiologists who joined, left, or were on extended leave (e.g., \>4 weeks) from the participating center between the with-AI and without-AI study periods. 2. Radiologists who interpreted fewer than the minimum required number of eligible scans in either study period. 3. Radiologists who voluntarily decline to have their de-identified performance data included in the study analysis. 4. Radiologists who decline to provide demographic or occupational information (e.g., years of professional experience or sex)-variables that may serve as potential confounders-will be excluded from adjusted and stratified analyses that require such covariates. 2.2 For Chest CT Scans 1. CT scans of pediatric patients (age \< 18 years). 2. Contrast-enhanced chest CT studies. 3. Studies performed for specific procedural guidance (e.g., biopsy, ablation). 4. Studies deemed technically inadequate for primary interpretation by radiologist (e.g., severe motion artifact, incomplete study). 5. Studies for which the AI system fails to generate a valid preliminary report draft. This includes possible system failures, algorithm errors, or cases where the generated draft is deemed technically unusable (e.g., empty, garbled, or based on critically flawed image analysis). 6. The lack of relevant information (diagnosis, clinical scenario, etc.). Chest CT data will be excluded from corresponding analyses if the required information, which is necessary for confounding control, subgroup analyses, or other pre-specified analyses, is unavailable. Such scenarios include data that cannot be retrospectively retrieved, incompletely recorded, or restricted due to ethical or institutional requirements.