Magnetic Resonance Imaging Reveals Meningeal Lymphatic Impairment in Lung Adenocarcinoma Brain Metastasis Progression

Meningeal lymphatic vessels (mLVs) contribute to brain immune surveillance; however, their structural and functional alterations in brain metastasis remain incompletely defined. Here, we optimized a magnetic resonance imaging protocol to quantitatively analyze mLV structure and drainage function. Using murine lung adenocarcinoma brain metastasis models and clinical imaging data, we reveal significant mLV disruption surrounding the superior sagittal sinus (SSS), which results in impaired drainage to deep cervical lymph nodes (dCLNs). Among ten cervical lymph-node levels assessed clinically, level IIA lymph nodes most accurately reflect mLV drainage efficiency. Functionally, mLV ablation compromised intrathecal chemotherapy efficacy in mice, while clinically, greater mLV structural and functional impairment correlates with disease progression in lung adenocarcinoma brain metastasis. Collectively, our findings demonstrate that lung adenocarcinoma brain metastases disrupt SSS-adjacent mLVs (mLVs-SSS), which potentially facilitates metastatic progression through compromised immune surveillance.