Have you ever hesitated in the face of a dizzying array of tests prescribed by your doctor? Have you ever wondered? Are these tests necessary? What is the significance of these tests? Here I will give you an introduction to the neurosurgery commonly used auxiliary examination, to unveil their mysterious veil. 1.Brain CT: It is a method to examine the cranium and brain through CT, and it is the most important diagnostic imaging method in the case of head trauma. Brain CT can clearly show the number, location, size, outline, density, intra-tumor hemorrhage, calcification and degree of diffusion of intracranial tumors. It is a simple, convenient, rapid, safe, painless and non-invasive examination method, which can clearly show different cross-sections of the skull and brain as well as specific brain structures, thus greatly improving the detection rate of lesions and the accuracy of diagnosis. 2.Magnetic Resonance Imaging (MRI): It is a MRI examination of the brain, which is used to observe whether there is any lesion in the brain, and can clarify whether the patient is caused by structural changes in the brain. Intracranial tumors often cause epilepsy, and the diagnosis and confirmation rate of MRI on low-grade astrocytes in the brain, ganglion, gliomas, arteriovenous malformations, and hematomas is extremely high. However, it should be noted that: metal objects cannot be brought into the examination area during the examination; watches, necklaces, rings, etc., should be removed before the examination; if there are metal substances in the head and face that cannot be removed (dentures, scalp suture needles, “A clips”, etc.), the doctor should be informed; those who have intrauterine devices should be removed before the examination; patients who are fitted with pacemakers, claustrophobic patients cannot have this examination. Patients with pacemakers and claustrophobia are not allowed to do this test. Evoked potential: It is to stimulate the sensory organs, sensory nerves, sensory pathways or any structures related to the sensory system, and produce measurable potential changes in the central nervous system to understand the functional changes of the brain. It is commonly used in the judgment of brain death, the localization of brainstem lesions, the diagnosis of acoustic neuroma, demyelinating diseases, the differential diagnosis of middle ear, inner ear and brainstem hearing disorders, and the safety monitoring in the posterior cranial recess and brainstem surgery. 4.Electroencephalogram (EEG): It is a graphic obtained by amplifying and recording the spontaneous bio-potentials of the brain from the scalp through an instrument. It is mainly applied to central system diseases, especially seizure diseases, preoperative localization of epilepsy surgery, traumatic brain injury and post-surgery monitoring of the brain, monitoring of critically ill patients, sleep disorders and so on. In the examination to remind you of a few points: ① no need to be nervous, scalp placed on the receiving electrode, not energized ② whole body muscle relaxation to avoid myoelectricity interference ③ according to the doctor’s request, open eyes, closed eyes or excessive breathing ④ except for special circumstances, three days before the examination to comply with the doctor’s instructions to stop using any drugs, especially the role of the nervous system of the drug ⑤ pay attention to observation of the patient’s condition during the drug suspension changes in a timely manner to detect aura of seizures, to protect the patient to ⑤ Observe the patient’s condition during the period of drug withdrawal, detect the aura of seizure in time, and protect the patient to avoid accidents ⑥ Wash the hair one day before the examination ⑦ Avoid pulling the electrode wires during the examination to avoid the electrodes from falling off ⑧ Notify the doctor immediately if there is a seizure during the examination and at the same time, protect the patient to avoid accidents 5.Electromyography (EMG): It is the application of electronic instrumentation to record the electrical activity of muscles at rest or during contraction, and is also a method of applying electrical stimulation to check neuromuscular and conduction functions. An EMG instrument usually consists of an amplifier, an oscilloscope, a recorder, a monitor, a stimulator and an averager. A weak electric current is generated when a muscle contracts, and by attaching electrodes at appropriate locations on the skin the current in the muscles on the surface of the body can be measured. This test is used in medicine to determine the functional status of peripheral nerves, neurons, neuromuscular junctions, and the muscles themselves. Precautions: Take a shower the day before the examination and wear loose-fitting underwear that easily exposes the upper and lower extremities for the examination. Do not perform the examination on an empty stomach to avoid discomfort. Do not wear jewelry. 6. Transcranial Doppler ultrasound (TCD): It is a non-invasive vascular examination method using ultrasound Doppler effect to detect the hemodynamics of major arteries in the intracranial cerebral basilar arterial ring and the physiological parameters of the blood flow, and through the detection of blood flow signals of different blood vessels in head and neck area, it can be used to diagnose cerebral atherosclerosis, cerebral vascular spasm, occlusion, etc. in the early stage. The above tests are commonly used auxiliary tests in neurosurgery, do you feel that the clouds are clearing up? Overall, each test has its own advantages and disadvantages, but also has its own specificity, and cannot be generalized. Doctors will decide what kind of tests need to be done according to the patient’s condition, and the tests prescribed by doctors are all justified.