MRI features and preliminary diagnostic assessment using large language models of cystic tumor progression mimicking radiation necrosis in brain metastasis patients treated with immunotherapy: Case Report

Guirong Tan^1,2Mingchen Cai²Yu Lu³Amy Liu⁴Shimin Li⁵Gang Xiao⁶Lijuan Zhong⁷Lijia Li²Yichuan Hu²Qiong Liang⁸Haihui Jiang⁹Xiang Liu^1,2*Henry Wang^10*

• ¹Advanced Neuroimaging Laboratory, Yuebei People's Hospital Affiliated to Shantou University Medical College, Shaoguan, Guangdong Province, China, Shaoguan, China
• ²Department of Radiology, Yuebei People's Hospital Affiliated to Shantou University Medical College, Shaoguan, Guangdong Province, China, Shaoguan, China
• ³Department of Medical Imaging, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China, Zhengzhou, China
• ⁴Nazareth University, Rochester, NY, United States, New York, United States
• ⁵The Radiotherapy Center of Neoplasm, Yuebei People's Hospital Affiliated to Shantou University Medical College, Shaoguan, Guangdong Province, China, Shaoguan, China
• ⁶Department of Neurosurgery, Yuebei People's Hospital Affiliated to Shantou University Medical College, Shaoguan, Guangdong Province, China, Shaoguan, China
• ⁷Department of Pathology, Yuebei People's Hospital Affiliated to Shantou University Medical College, Shaoguan, Guangdong Province, China, Shaoguan, China
• ⁸Department of Pathology, the Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China, Guangzhou, China
• ⁹Department of Neurosurgery. Peking University Third Hospital, Peking University, Beijing, China, Beijing, China
• ¹⁰Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, United States, New York, China

The application of immunotherapy in patients with brain metastasis (BM) has increased rapidly in recent years, which led to a diagnostic dilemma between pseudoprogression and true progression in the post-treatment evaluation. Here, we reported MRI characteristics of pathology-confirmed large cystic rim-enhancing lesions of tumor progression in two BM cases with immunotherapy treatment, which mimicked radiation necrosis on conventional MRI. In addition, our preliminary findings showed that the custom large language models (LLMs) using ChatGPT and DeepSeek yielded correct diagnoses in these cases, which may suggest the potential utility of LLMs for the decision-making in this field.