Preoperative MRI and CA19-9 for predicting occult lymph node metastasis in small pancreatic ductal adenocarcinoma (≤ 2 cm). - Qiying Tang; Lei Li; Zhiwei Pan; Jianbo Li; Xiaolan Huang; Mengsu Zeng; Haitao Sun; Jianjun Zhou (BMC Medical Imaging, 2025)