Comparison of online radiologists and large language model chatbots in responding to common radiology-related questions in Chinese: a cross-sectional comparative analysis.

Background: Additional avenues for medical counseling are needed to better serve patients. In handling medical counseling, large language model chatbots (LLM-chatbots) have demonstrated near-physician expertise in comprehending enquiries and providing professional advice. However, their performance in addressing patients' common radiology-related concerns has yet to be evaluated. This study thus aimed to investigate the effectiveness and model performance of LLM-chatbots (DeepSeek-R1 and ChatGPT-4o) in radiology-related medical consultation in the Chinese context through both subjective evaluations and objective metrics. Methods: In this cross-sectional study, common radiology-related questions were collected from the HaoDF online platform, one of the largest Chinese public healthcare service platforms. All questions were posed to the LLM-chatbots from February 24 to February 30, 2025. To facilitate comparison between LLM-chatbots and online radiologists, three senior radiologists from different medical centers were recruited as reviewers, and they blindly scored LLM-generated responses using a 5-point Likert scale across the three subjective dimensions: quality, empathy, and potential harm. Objective metrics including textual features (six metrics across three linguistic dimensions: lexical, syntactic, and semantic), response time, and self-improvement capacity were calculated as additional evaluators for the performance of the two LLM-chatbots. Results: A total of 954 reviews were generated for 318 responses to 106 questions. LLM-chatbots achieved superior scores in quality, empathy, and potential harm as compared to the online radiologists (all P values <0.001). Among the LLM-chatbots, DeepSeek-R1 outperformed ChatGPT-4o in terms of quality scores [DeepSeek-R1: mean 4.40, standard deviation (SD) 0.57; ChatGPT-4o: mean 3.73, SD 0.64; P<0.001]. The response times were significantly shorter for DeepSeek-R1 [median 56.00 s; interquartile range (IQR), 47-67 s] and ChatGPT-4o (median 12.17 s; IQR, 10.91-15.85 s) as compared to online radiologists (median 6,487.90 s; IQR, 3,530.50-29,061.70 s), and the LLM-chatbots generated greater textual complexity (as measured by six metrics across three linguistic dimensions: lexical, syntactic, and semantic) (all P values <0.001). Among the two chatbots, ChatGPT-4o generally produced linguistically simpler responses (all P values <0.001), with comparatively shorter response times (median 12.17 s; IQR, 10.91-15.85 s), than did DeepSeek-R1 (median 56.00 s; IQR, 47-67 s) across various topics (P<0.001). Additionally, both LLM-chatbots demonstrated a degree of self-improvement ability. Conclusions: These findings highlight the potential utility of LLM-chatbots in addressing the common radiology-related inquiries initially posed by patients. However, further optimization and validation are required to establish this emerging technology as a productive and effective pathway in medical counseling.