Ultrasound of the brain cannot detect tumor. Ultrasound of the brain, also known as TCD, mainly examines the blood flow of the blood vessels in the brain, such as the anterior cerebral artery, middle cerebral artery, posterior cerebral artery, basilar artery and vertebral artery to see if there is insufficient blood supply or increased blood flow, and can also check whether there is vascular spasm in the brain. The examination of brain tumor is mainly based on cranial CT or cranial MRI scan and enhancement, and then the diagnosis of brain tumor is based on the clinical symptoms of the patient. For metastases in the brain, cranial magnetic resonance examination is also performed to clarify, so brain ultrasound is only to check whether there is narrowing of blood vessels in the brain, insufficient blood supply and vascular spasm in the brain, and it cannot check tumor.