1.What are the precursors of brain metastasis in lung cancer patients? What are the common symptoms of lung cancer brain metastasis patients? Patients with lung cancer, such as headache, vomiting, epilepsy and focal neurological deficits, etc. often indicate the possible occurrence of brain metastasis. Therefore, patients with a history of lung cancer should go to neurosurgery department in time once the above symptoms appear. 2.How to confirm the diagnosis of brain metastasis of lung cancer? What tests are required? For patients with headache, vomiting, epilepsy and focal neurological deficits and other manifestations and suspected brain metastasis of lung cancer, initial screening can be performed by head CT examination, but some smaller lesions may be missed, especially those in the brainstem and cerebellum located in the posterior cranial fossa. Therefore, plain + enhanced cranial MRI is preferable, which typically shows homogeneous enhancing or ring enhancing lesions in the gray-white matter junction area of the brain, with intra-tumoral hemorrhage and necrosis and severe peritumoral edema.