The study design is summarized in Figure 1. Radiology report texts from 3 imaging modalities (x-ray, CT, and MRI) and 5 anatomical regions (head, chest, abdomen, spine, and knee) were retrospectively collected from center 1 (the Second Affiliated Hospital of Kunming Medical University) between March 2025 and May 2025. Inclusion criteria were (1) complete reports containing imaging modality, anatomical location, descriptive findings, and diagnostic conclusion; and (2) exclusion of emergency or functional imaging studies. All reports were initially drafted by junior radiologists (residents to attending physicians with 1‐7 years of experience) and subsequently reviewed by senior radiologists (associate chief physicians or above with ≥8 years of experience) as part of routine clinical workflow. All radiology reports were exported from the picture archiving and communication system and deidentified. We removed patient names, sexes, ages, inpatient numbers, accession numbers, contact details, addresses, dates of birth, examination dates, institution names, physician names, and any other direct or indirect identifiers. The retained data comprised the imaging modality, examination item, imaging findings, and diagnostic impression. Each record was assigned a randomly generated study ID in place of its original identifier. A linkage file connecting the study IDs to the original patient records was retained only within a restricted institutional environment. This file was not provided to any model or third-party platform.

Error annotations adhered to a standardized taxonomy established through previous literature and expert consensus [1,9] (Table 1). Radiology report errors were classified into five mutually exclusive categories: (1) omission (a finding documented in the imaging findings that was absent from the diagnostic impression or a diagnosis in the diagnostic impression that lacked any corresponding description in the imaging findings); (2) inconsistency (logical contradiction between description and impression [eg, “clear fracture line” is described, but the diagnosis states “no evidence of fracture”]); (3) laterality confusion (incorrect anatomical side or orientation [eg, “right” mislabeled as “left”]); (4) nonlogical errors due to inadvertent insertion of incorrect terms, including word misuse, typographical errors, irrelevant content, or lexical substitution; and (5) other errors (technical or formatting mistakes not covered above, such as impression numbering errors, unit mislabeling [eg, centimeters vs millimeters], or punctuation-induced ambiguity). Reports without errors were labeled as “N.” Errors 1 and 2 were grouped as type 1 (interpretive errors), whereas errors 3 to 5 constituted type 2 (factual errors). All 5 error categories were defined as text internal errors identifiable from the radiology report text alone. The taxonomy did not include imaging findings that were absent from the entire report and could be identified only through direct review of the source images. All reports were independently reviewed by 2 senior radiologists with 18 and 21 years of clinical experience to establish the report text reference standard labels. Discrepancies were resolved through consensus adjudication. The reviewers assessed only the report text and had no access to the corresponding source images, patient clinical records, or LLM outputs.

Five LLMs were evaluated: Qwen3-2507 (Alibaba Cloud; hereafter referred to as “Qwen3”), GPT-5.4 Pro (OpenAI), Gemini 3.1 Pro (Google DeepMind), Llama 4 (Meta AI), and DeepSeek-V3.1. All models were accessed via an OpenAI-compatible cloud API end point provided by GeekAI [22] and initially benchmarked using a randomly selected subset of 10,000 expert-annotated reports comprising 3000 x-ray reports, 4000 CT reports, and 3000 MRI reports. The LLM that demonstrated optimal performance was selected as the primary model for comprehensive analysis. The temperature parameter, which controls output randomness, was set to 0.1 to prioritize deterministic, conservative outputs aligned with the clinical imperative of minimizing false negatives. The models received only the textual content of the radiology reports; no medical images or other input modalities were provided. “X-ray,” “CT,” and “MRI” indicate the imaging examinations from which the report texts originated. The radiology report quality check prompt and translated report error detection examples are shown in Multimedia Appendix 1. Radiology report quality control was performed using Qwen3.

A blinded, head-to-head evaluation was conducted to compare error detection and categorization performance between radiologists and the AI model. This study used a challenge set comprising 300 randomly selected reports (100 each from x-ray, CT, and MRI examinations) drawn from the expert-confirmed error-positive reports in the center 1 cohort. Three radiologists with differing experience levels participated, including Drs A (10 years), B (6 years), and C (3 years). These radiologists independently reviewed the reports for errors without access to source images, clinical history, reference labels, or model outputs. Participants were instructed to identify all errors and assign each to one of 5 prespecified taxonomy categories. Prior to the formal evaluation, all radiologists were trained on the taxonomy definitions and examples (Table 1) and completed a pilot session with 5 reports, which were excluded from the final analysis. Error detection assessments were locked upon submission. No further modifications were allowed. Review time was recorded, which was defined as the time required to complete the experimental text-only report auditing task for each report modality.

Report-level error detection sensitivity was defined as the proportion of error-containing reports in which at least one error was identified. Report-level exact set matches were counted as correct only when the complete set of predicted error categories exactly matched the adjudicated reference set; missed categories and additional incorrect categories were counted as failures. Error instance–level exact category recall was calculated as the number of ground truth error instances assigned the correct category divided by the total number of ground truth error instances.

To evaluate the clinical interpretability and reasoning validity of error detections generated by Qwen3, a total of 3 radiologists (Drs A, B, and C) independently rated the model’s explanatory rationales for errors identified in 300 radiology reports (100 each from x-ray, CT, and MRI examinations) using a 5-point Likert scale [23] (5=“strongly agree,” 4=“agree,” 3=“neutral,” 2=“disagree,” and 1=“strongly disagree”). The explanation rating task was performed separately after error detection. The explanations were presented without model identifiers, and the radiologists were blinded to their origin. The final score for each report was defined as the mean of the 3 reviewers’ ratings. Approximately 4 months after the initial assessment, the same radiologists re-evaluated a subset of reports. The subset consisted of 30 randomly selected reports for each of the 3 imaging modalities. The original scoring criteria were used. Reports were presented in a new random order. Radiologists were blinded to the scores of other reviewers.

To evaluate the robustness of Qwen3 and its cross-institutional generalizability, we conducted external validation on an independent dataset of 44,839 real-world radiology reports retrospectively collected from center 2 (the Sixth Affiliated Hospital of Kunming Medical University). The dataset included reports from the same 3 imaging modalities (x-ray, CT, and MRI) and covered major anatomical sites, including head, chest, abdomen, and spine. The same 2 senior radiologists independently labeled reports from both centers using the same prespecified taxonomy and annotation protocol.

Primary performance metrics included accuracy, balanced accuracy, sensitivity, specificity, precision, positive predictive value, negative predictive value, Matthews correlation coefficient, and F₁-score. The Cohen κ was used to assess interrater agreement between the 2 senior radiologists’ initial independent labels for report-level error presence and error categories before consensus adjudication. Intraclass correlation coefficients were used to assess inter- and intraobserver agreement of radiologists’ Likert ratings. All statistical analyses and visualizations were performed using Python (version 3.11.4; Python Software Foundation); Microsoft PowerPoint (version 2407) was used for figure assembly. Statistical significance was defined as P<.05.

This retrospective study was approved by the institutional review boards of center 1 (IPJ2025202) and center 2 (2025kmykdx6f157). Informed consent was waived due to the retrospective design. No protected health information was provided to the LLMs. This study was reported in accordance with the STARD-AI (Standards for Reporting of Diagnostic Accuracy Studies–AI) reporting guidelines.

The main study dataset comprised 95,582 real-world radiology report texts from the 3 primary imaging modalities: x-ray (n=10,036, 10.5%), CT (n=67,215, 70.3%), and MRI (n=18,331, 19.2%). Among these, 95.4% (91,151/95,582) were error free, and 4.6% (4431/95,582) contained at least one confirmed error (Figure 1). Instance-level analyses included 95,908 labeled instances, comprising 91,192 error-free labels and 4716 true error instances. For 10,000 randomly selected reports (x-ray: 3000; CT: 4000; MRI: 3000), Qwen3 demonstrated superior error detection accuracy (0.96), establishing it as the optimal model for subsequent analysis (Figure S1 in Multimedia Appendix 1).

Qwen3 demonstrated modality adaptability and anatomical region robustness in exact label error detection for free-text radiology reports (Figure 2). Across 95,908 labeled instances, the model achieved accuracy of 0.99, balanced accuracy of 0.98, macroprecision of 0.91, macro–F₁-score of 0.94, and weighted F₁-score of 0.99. Performance remained high across radiology reports originating from the 3 imaging modalities, with weighted F₁-score values of 1.00 for x-ray, 1.00 for CT, and 0.99 for MRI. The error rate was 0.5% (52/10,089) for x-ray, 0.6% (368/67,402) for CT, and 1.2% (224/18,417) for MRI, suggesting relatively more false classifications in the longer MRI reports.

Model discrimination remained stable across anatomical regions (Figure 2). Weighted F₁-score was 1.00 for head, 1.00 for chest, 0.99 for abdomen, 0.98 for spine, and 0.99 for knee. The highest error rate was observed in spine reports (148/6845, 2.2%), whereas head and chest reports had lower error rates of 0.3% (44/14,853) and 0.5% (205/44,957), respectively. These findings indicate that spine reports were more prone to false classifications, consistent with their greater narrative complexity.

In joint stratification by modality and anatomical region, performance remained high but showed clinically relevant heterogeneity (Figure 2). X-ray chest reports showed a weighted F₁-score of 1.00 and an error rate of 0.46%. CT spine and MRI spine reports were more challenging, with weighted F₁-score values of 0.98 and error rates of 2% (36/1768) and 2.5% (109/4301), respectively.

The results of the error type and granularity analysis are shown in Figure 3. Type 2 factual errors were detected more reliably than type 1 interpretive errors. In the primary cohort, type 1 errors achieved accuracy of 0.96, balanced accuracy of 0.95, macroprecision of 0.98, and macro–F₁-score of 0.96. Type 2 errors achieved accuracy of 1.00, balanced accuracy of 1.00, macroprecision of 1.00, and macro–F₁-score of 1.00.

Subtype-level analysis confirmed this pattern. Omission errors (subtype 1) had a precision of 0.83, recall of 0.96, and F₁-score of 0.89; inconsistency errors (subtype 2) had a precision of 0.75, recall of 0.93, and F₁-score of 0.83. Factual subtypes performed better: laterality confusion (subtype 3) had an F₁-score of 0.94; semantic errors (subtype 4) had an F₁-score of 0.98; and other factual errors (subtype 5) had precision, recall, and F₁-score of 1.00. Tables S1 to S4 in Multimedia Appendix 1 provide additional hierarchical and fine-grained classification results.

An error-enriched, modality-stratified challenge set of 300 radiology reports randomly sampled from expert-confirmed error-positive reports (100 each of x-ray, CT, and MRI examinations) was independently evaluated by 3 radiologists with varying levels of experience and Qwen3. The reports contained 335 expert-confirmed error instances, including 116 x-ray instances, 107 CT instances, and 112 MRI instances (Figures 4A and 4B). The results for report-level error detection sensitivity and report-level exact set match are provided in Tables S5 and S6 in Multimedia Appendix 1. Qwen3 correctly classified 320 of 335 error instances (0.96) compared with 223 of 335 (0.67), 178 of 335 (0.53), and 152 of 335 (0.45) for Drs A, B, and C, respectively. By modality, Qwen3 achieved exact category recall rates of 0.95 for x-ray, 0.96 for CT, and 0.96 for MRI. The corresponding rates were 0.72, 0.64, and 0.62 for Dr A; 0.63, 0.51, and 0.45 for Dr B; and 0.52, 0.50, and 0.35 for Dr C, respectively.

When stratified by broad error category, Qwen3 achieved exact category recall rates of 0.94 for type 1 interpretive errors and 0.97 for type 2 factual errors (Figure 4B). The corresponding rates were 0.62 and 0.70 for Dr A, 0.58 and 0.49 for Dr B, and 0.51 and 0.41 for Dr C, respectively.

Comparison of review time showed that Qwen3 processed reports faster than all human reviewers (Figure 4C). Mean processing time was 5.80 seconds per report, compared with 55.80 seconds for Dr A, 61.20 seconds for Dr B, and 67.80 seconds for Dr. C. Thus, the model was approximately 9.6 to 11.7 times faster than human reviewers in this constrained text auditing task.

Human review times exhibited a systematic dependence on imaging modality: for x-ray reports, radiologists A, B, and C required 28.80, 33.00, and 37.20 seconds; for CT reports, they required 63.60, 70.80, and 81.00 seconds; and for MRI reports, they required 75.00, 79.20, and 85.20 seconds, respectively. Review time increased markedly with modality complexity, particularly from x-ray to MRI. Human review time was longer for CT and MRI report texts than for x-ray report texts, potentially reflecting differences in report length and textual complexity. In contrast, Qwen3 processed radiology reports efficiently across the 3 imaging modalities, with processing times of 5.60 seconds for x-ray, 6.80 seconds for CT, and 5.00 seconds for MRI, all below 7 seconds per report.

Figures 5A and 5B show that the LLM’s error reasoning received consistently high evaluations from all 3 radiologists, with an overall mean score of 4.57 (SD 0.86) on the 5-point Likert scale. Stratified by imaging modality, reasoning quality remained high across x-ray (4.63, SD 0.81), CT (4.57, SD 0.84), and MRI (4.52, SD 0.94).

When stratified by error type, a subtle but consistent difference in reasoning quality was observed. The mean score for type 2 (factual) errors was 4.63. This indicates that the model’s explanations for rule-based, discrete errors, such as laterality confusion, unit mislabeling, or typographical slips, were deemed highly reliable and unambiguous by clinicians. In contrast, the mean score for type 1 (interpretive) errors was 4.49, slightly lower but still within the “agree” to “strongly agree” range. This small yet consistent gap suggests that reasoning about interpretive errors such as omissions or description-diagnosis inconsistencies posed a greater challenge for the LLM. Notably, across all modalities, type 2 errors consistently received higher scores than type 1 errors (x-ray: 4.64 vs 4.61; CT: 4.63 vs 4.47; MRI: 4.61 vs 4.40), further confirming that the explicit and well-defined nature of factual errors renders them more amenable to accurate and interpretable algorithmic explanation. Inter- and intraobserver intraclass correlation coefficient values for the Likert ratings exceeded 0.89 (Tables S7 and S8 in Multimedia Appendix 1).

The external validation dataset comprised 44,839 real-world radiology reports from center 2, including 5927 (13.2%) x-ray reports, 32,587 (72.7%) CT reports, and 6325 (14.1%) MRI reports. External instance-level analysis included 44,907 labeled instances (Figures 6A-6C). Overall accuracy was 1.00 (95% CI 1.00-1.00), balanced accuracy was 0.94 (95% CI 0.92-0.95), macro-precision was 0.92 (95% CI 0.90-0.94), macro-F1 was 0.93 (95% CI 0.91-0.94), and weighted F1 was 1.00 (95% CI 1.00-1.00). By modality, balanced accuracy was 0.95 (95% CI 0.90-0.98) for x-ray, 0.94 (95% CI 0.91-0.96) for CT, and 0.92 (95% CI 0.88-0.95) for MRI. Error-positive body region analysis showed macro-F1 scores of 0.97 (95% CI 0.94-0.99) for chest, 0.93 (95% CI 0.89-0.97) for head, 0.90 (95% CI 0.86-0.94) for abdomen, and 0.84 (95% CI 0.80-0.89) for spine. Detailed metrics are provided in Tables S9 to S14 and Figure S2 in Multimedia Appendix 1.

Before consensus adjudication, the same 2 senior radiologists showed substantial interrater agreement for report-level error presence at both centers (center 1: Cohen κ=0.783, 95% CI 0.773‐0.792; center 2: Cohen κ=0.850, 95% CI 0.837‐0.863; P<.001 in both cases). Overall, positive, and negative agreement were 97.93%, 79.35%, and 98.91% at center 1 and 98.90%, 85.60%, and 99.43%, respectively, at center 2. Among consensus-confirmed error-positive reports, category-specific Cohen κ values ranged from 0.816 to 0.975 at center 1 and from 0.841 to 0.985 at center 2 (P<.001; Tables S15 and S16 in Multimedia Appendix 1).

This study provides real-world evidence to validate the feasibility and performance of a general-purpose LLM for radiology report error detection in real clinical settings across radiology reports from 3 imaging modalities (x-ray, CT, and MRI), multiple anatomical regions, and 2 institutions. Unlike prior work relying on synthetic datasets [1], our study used a fine-grained, expert-anchored error taxonomy to ensure high ecological validity. Key findings are as follows: (1) Qwen3 showed robust generalizability across radiology reports from the 3 imaging modalities, multiple anatomical regions, and 2 institutions; and (2) in blinded head-to-head comparison, the model achieved higher exact category recall rates than senior radiologists and processed reports nearly 10 times faster while providing clinically credible explanations. These results indicate that general-purpose LLMs can serve as transparent and efficient auditing tools, offering a scalable solution for radiology quality assurance.

The study shows that Qwen3 performs robustly across free-text radiology reports from all 3 imaging modalities, indicating its ability to adapt to diverse reporting structures and error contexts [24]. However, model performance correlated with the linguistic standardization of reports, not with the inherent complexity of the imaging modality [25]. We observed the best performance in highly structured chest x-ray reports. In contrast, spinal CT and MRI reports posed greater challenges due to complex descriptions of degenerative changes and extensive synonym variation (eg, “osteophyte,” “sclerosis,” and “spur”). This performance gradient suggests that scaling model size alone may not resolve domain-specific limitations. Future deployment should incorporate anatomy-specific fine-tuning or context-enhanced prompting strategies [26,27].

Regarding error taxonomy, Qwen3 demonstrated excellent reliability in detecting rule-based “factual errors” (type 2 errors). These include errors such as laterality confusion and unit mistakes. However, the model showed relatively weaker performance for “interpretive errors” (type 1 errors). These errors require cross-sentence reasoning. This finding suggests that LLMs should help preserve expert cognitive bandwidth for intricate diagnostic tasks [27,28]. Another possible contributor to the lower performance for interpretive errors is that the model operated exclusively on report text and had no access to the corresponding images. Therefore, it could assess the internal consistency and completeness of the report text but could not independently determine whether an imaging finding had been overlooked or misinterpreted. The mismatch exists between the need for deep clinical reasoning and the capabilities of text-only LLMs. It does not reflect a deficiency in medical language understanding itself [29,30].

Comparisons with radiologists of varying seniority levels revealed the advantages of the LLM. The model maintained high error instance exact category recall while operating significantly faster than human readers. Furthermore, the participating radiologists rated the model-generated explanations favorably, supporting their perceived clarity and clinical plausibility within the evaluated text auditing task. This establishes a foundation of trust for using the model as an assistive quality control tool [31]. These findings support a risk-stratified implementation strategy for clinical practice. High-confidence detections of type 2 errors can trigger automatic alerts for immediate correction. For type 1 errors, we suggest using model outputs as prompts for radiologist review. Furthermore, the model offers advantages in processing speed (less than 7 seconds per report) and cross-center generalization. The model’s short processing time suggests that it may be compatible with high-throughput clinical workflows while adding minimal time burden [20,32]. Its consistent performance across centers further supports its potential applicability in different clinical settings.

Under the workload and token pricing assumptions used in this study, the estimated recurring API cost was approximately US $0.00035 to US $0.00347 per report. Relative to the operational scale of a large tertiary hospital, this represents a modest per-report expenditure. Together with the observed performance of the model in radiology report text quality control, these estimates suggest potential economic feasibility and clinical translational value for the proposed workflow. However, formal cost-effectiveness remains to be established through real-world implementation studies that account for infrastructure, personnel, maintenance, workflow integration, and long-term operational costs.

This study has several limitations. First, the use of Chinese-only reports may limit generalizability to other languages. Second, some interpretive error labels remain subjective despite expert adjudication. Third, this study evaluated only errors identifiable from report text and could not assess image-report concordance or detect errors requiring direct interpretation of the source images. Future studies should evaluate vision language models that jointly incorporate medical images, report text, and relevant clinical context. Fourth, in the human-AI comparison, radiologists did not have access to the source images or patient clinical information, unlike in routine practice. Therefore, LLM performance in clinical image interpretation and routine report review requires further validation. Recorded human review times reflected only the experimental task and not routine clinical workflow. Fifth, model processing times for reports from different imaging modalities may have been affected by input and output text length, API and network latency, and server load. The observed differences should therefore not be interpreted as inherent modality-specific differences in report text processing efficiency under real-world clinical conditions. Finally, we did not categorize error severity based on clinical impact, which warrants further investigation with subspecialty involvement.

In conclusion, our findings suggest that LLMs can serve as efficient adjunctive tools for detecting prespecified text internal errors in radiology reports, particularly explicit factual errors. Although challenges remain in context-dependent interpretive reasoning, the model’s efficient report text processing, scalability, and decision logic that were judged acceptable by radiologists suggest that it may support text-level quality assurance amid increasing clinical workloads.