Once hydrocephalus is suspected, the following are some of the mandatory tests: A cranial CT scan, which is the easiest and fastest means of detecting head disease. It can detect ventricular dilatation and initially rule out intracranial hemorrhage and the presence of occupational disease such as tumors. The disadvantage is that for infants and young children, there is a certain amount of radiation that may affect development, and there are no clear conclusions about this damage. Cranial MRI scan, MRI is more reliable for the diagnosis of hydrocephalus and can detect some conditions that cannot be detected by cranial CT, such as the site of obstructive adhesions and whether there is a tumor. And the MRI radiographic technique developed in recent years can make judgments about the flow of cerebrospinal fluid, and this technique can be used as an effective means to compare before and after treatment to determine the effect of treatment. Lumbar puncture, which is the most important test before hydrocephalus treatment, can measure the intracranial pressure and assay the cerebrospinal fluid condition. Brain pool imaging, which is performed by injecting a contrast agent into the subarachnoid space while lumbar puncture is performed and maintaining the patient in a low-hip position for 15 minutes, and doing a cranial CT scan to check the distribution of the contrast agent and discover the location of the obstruction so that the next treatment plan can be decided. Visual acuity and fundus examination for edema of the optic nerve papillae and hemorrhage in the fundus.