Nervous system nuclear medicine examination

Nervous system nuclear medicine is commonly used in tomosynthesis or non-imaging methods with local cerebral blood flow, brain plane and tomography, and brain pool imaging. With the development of tomographic imaging instruments, techniques and radiopharmaceuticals, in recent years, brain metabolic imaging and neuroreceptor imaging using positron emission tomography (PECT) have been developed in high-tech fields, such as the brain. Local glucose metabolism, protein metabolism, receptor density and other issues closely related to central nervous system function, nuclear medicine molecular biology imaging method can be used for living human brain research, and has a variety of neurological and mental disorders The value of early diagnosis. Neurological nuclear medicine examination mainly includes cerebral blood perfusion (rCBF) imaging, brain metabolic imaging, central neurotransmitter and receptor imaging, radionuclide cerebrovascular imaging, and cerebrospinal fluid imaging. Basic Information Specialist Category: Neurological Classification: Radionuclide Applicable gender: whether men and women apply fasting: not fasting Tips: Stop taking sedatives, stimulants and other drugs that act on the nervous system 24 hours before the test to avoid the formation of illusions during the examination and affect the judgment of the test results. Normal value 1. Local cerebral blood flow tomography is normal. The blood flow of gray matter structures such as normal human large, cerebellar cortex, basal ganglia, thalamus and brainstem is higher than that of white matter, showing a radioactive concentration zone. The radioactivity in the white matter and ventricles is significantly lower. The radioactivity distribution of the left and right brain tissues is basically symmetrical. 2, the brain pool imaging is normal. Normal people see the cerebellar medullary pool image 1 h after the injection. After 3-6 hours, the basal cisterns are successively imaged, showing an upward trigeminal shape with a base cerebral pool and a quadruple. In the pool, the central part is the corpus callosum, and the two sides are the outer lobes. The gap between them is the lateral ventricle. At 24h, the shadows of the basal cells disappeared, and the radioactivity was concentrated to the convex surface of the brain. The shape was like an umbrella, and the above images were basically symmetrical. Clinical significance Abnormal result I. Local cerebral blood flow tomography (1) Diagnosis of ischemic cerebrovascular accident: 1 cerebral infarction, the radioactivity of the lesion is significantly lower than the corresponding part of the healthy side, and the positive rate of γCBF is close to 100%. In the 2 to 3 days after the onset, no obvious structural changes have been formed in the lesion area, so XCT and MRI often fail to show abnormalities. This method has high clinical value for early diagnosis, disease estimation and prognosis of cerebral infarction; 2 transient ischemic attack (TIA), sudden onset, rapid disappearance of symptoms, XCT and MRI positive after symptoms disappear The rate is only 25%, and γCBF imaging can occur 50% of patients with TIA still have ischemic changes in the brain. The timely detection and treatment of this chronic hypoperfusion state is of great significance in the prevention of cerebral infarction. (2) Diagnosis of epilepsy lesions: At the time of seizures, the γCBF of the lesions increased significantly, but decreased during the interictal period, and the positive rate was 60%, which was much higher than XCT (25%). This method has important value for the localization diagnosis of epilepsy lesions and can be used as the basis for surgical treatment. (3) Diagnostic value of brain tumor: The positive rate of diagnosis of brain tumor is similar to XCT, and its unique value is that 1 can judge the degree of malignancy of brain tumor according to the amount of radioactivity concentrated in brain tumor, that is, the amount of blood flow. In addition to blood-rich meningiomas, the blood flow of brain tumors increases with the increase of malignant degree; 2 monitoring the recurrence of brain tumors after surgery and radiotherapy, if γCBF increases again, suggesting that brain tumors recur; if γCBF Reduction may be scar formation or necrosis. Second, brain imaging (1) Diagnosis of brain tumor: The positive rate of diagnosis of brain tumor in this method is close to 90%. The positive rate of lesions located in the cerebral hemisphere can be as high as 95%; the positive rate of lesions in the midline, skull base and posterior cranial fossa is low. The resolution of this method is not as good as XCT and MRI, and can not meet the requirements of anatomical information required for surgical treatment. Therefore, units with XCT and MRI equipment have been used less. (2) Diagnosis of cerebral infarction: Within 1 week of onset, there was no obvious abnormality in the imaging image, and the positive rate reached 80% within 2 to 8 weeks, and gradually became negative after 8 weeks. The local radioactive concentration zone of a typical lesion is wedge-shaped, consistent with the blood supply area of ​​the damaged vessel, and does not exceed the midline. (3) Diagnosis of subdural hematoma: The positive rate can reach 90%. On the anterior brain image, the outer edge of the affected side has a more dense crescent-shaped radioactive concentration zone. Third, brain pool imaging (1) Diagnosis of traffic hydrocephalus: The typical imaging feature of this disease is that 1 radioactive tracer enters the lateral ventricle and remains for more than 24 hours; 2 the tracer is slowly eliminated, and the convex surface of the brain is still not visible 24 to 48 hours; but sometimes Only one of the above phenomena occurs. This method is the only method that can diagnose the disease and is of great significance for guiding treatment and observing the curative effect. (2) Diagnosis and localization of cerebrospinal fluid leakage: This method can display abnormal radioactive concentration images of cerebrospinal fluid leakage and leaky tube parts, which can help to diagnose ear leaks and rhinorrhea. (3) Brain abscess: This method is more sensitive to the diagnosis and follow-up of brain abscess. If the abscess has formed a abscess, it will show a "fried noodle" pattern. People in need of examination: patients suspected of ischemic cerebrovascular accident, epilepsy, brain tumor, cerebral infarction, subdural hematoma, hydrocephalus, brain abscess. Precautions Taboo before inspection: First, cerebral blood flow imaging 1. Stop taking sedatives, stimulants and other drugs that act on the nervous system 24 hours before the test to avoid the formation of illusions during the examination and affect the judgment of the test results. 2, oral potassium perchlorate 400mg 30 minutes before the examination to close the choroid plexus. 3, 10 minutes before the injection of imaging agents, you should wear a black eye mask and earplugs, until 10 minutes after the injection can be removed, before the imaging has been closed and quiet rest. Second, brain metabolism imaging 1, drinking water: 30 minutes after the injection of 18F-FDG, drinking 3-4 cups, about every 10 minutes. 2. Remove the metal accessories (such as belts, keys, necklaces, jewelry, coins, etc.) worn by the body before imaging. 3. Drain the urine before the imaging (be careful not to stain the clothes or skin with urine to avoid misdiagnosis). 4. The examinee started fasting, banned alcohol, banned drinking sugary drinks, banned intravenous drip of glucose, and banned from vigorous or prolonged exercise at 9:00 pm on the day before the examination. Drink a small amount of water. 5, check the day to avoid talking with people, do not chew gum, etc.; avoid stressful position. 6. When you come to the PET/CT center, please bring along the relevant information (medical records, treatment records, pathological results, imaging examination data such as CT, X-ray, MRI, DSA, B-ultrasound, bone imaging, etc.). Third, central neurotransmitter and receptor imaging and radionuclide cerebrovascular imaging 1. For radionuclide cerebrovascular imaging examination, radionuclide-labeled drugs must be injected. Before the patient is examined, the first-time physician should be consulted in detail and signed to confirm the radionuclide cerebrovascular imaging examination. 2. Remove metal objects from the body before imaging to prevent artifacts. 3, the recent use of tincture, patients must discharge the tincture and then make an appointment to check. Requirements for inspection: First, cerebral blood flow imaging 1. The examination must be carried out within 3 hours after the meal. If you cannot eat before the examination, you should follow the doctor's arrangement, orally take 50 grams of sugar powder or intravenously inject 50 ml of 50% glucose to prevent the examination due to hypoglycemia. result. 2. The head cannot move during the inspection to ensure the authenticity of the image. Second, brain metabolism imaging 1. Keep quiet before and after injection of imaging drugs, and rest in a lying position or a semi-recumbent position, try to avoid walking. 2, need to calmly breathe during the examination, it is not appropriate to take a deep breath; some subjects need to hold their breath for a few seconds (according to the doctor's advice). 3, keep the position does not move, the best hands to lift the whole body examination, check about 15 ~ 20min; brain examination does not require hands to lift, check about 5 ~ 10min. Third, central neurotransmitter and receptor imaging and radionuclide cerebrovascular imaging 1. Let the body relax and lie flat during the development process, and do not move the body. 2. Lumbar puncture and cerebellar medullary puncture should be performed by a neurologist. Inspection process First, cerebral blood flow imaging 1, cerebral blood flow perfusion imaging. Before the cerebral blood perfusion imaging, the patient took oral potassium perchlorate 400mg to block the uptake of pertechnetate (99mTcO4) by the choroid plexus. After 30 minutes, the cerebral blood flow perfusion imaging agent 99m锝 double was injected through the elbow vein. Cysteine ​​ethyl ester (99mTc-ECD) 740925mBq. The collection was started 30 minutes after the injection. The patient lies on the fault bed and brakes his head. Acquisition matrix 128×128, magnification 1.0, step acquisition, 1 frame per rotation, 6 frames, a total of 60 frames, 2530s per frame. The original data was processed by a computer workstation (X-Pert) and the reconstruction was performed with Henning filtering with an attenuation correction factor of 0.11. Cross-sectional, coronal, and sagittal tomographic images parallel to the line connecting the external and external ear holes were obtained. 2. Acetazolamide load test. After 48 hours of brain SPECT examination, 2 g of acetazolamide (produced by Jiangsu Chennai Pharmaceutical Co., Ltd.) was taken orally, and SPECT examination was performed 2 hours later. The other steps are the same as above. 3, 133Xe cerebral blood flow measurement and imaging. The subject was placed on his back, and the head was placed in a helmet of a multi-probe detecting device, and a 133Xe 133Xe-O2 mixed gas of 185 MBe/L was inhaled for 1 min, followed by inhalation of air for 15 min. The multi-probe system was started to record for 10~15min, and the rCBF and the gray matter flow distribution map of the corresponding parts of each probe were obtained by computer processing. If tomographic imaging must be completed in a short time using a high-speed rotation and high-sensitivity SPECT system. 4. SPECT image analysis. Qualitative analysis was performed by two doctors using visual methods, and abnormalities in the radioactivity that were visible to the naked eye on two or more mutually perpendicular levels were considered lesions. The X-Pert workstation computer-specific software was used for quantitative analysis. The cerebellar regional cerebral blood flow (rCBF) was 100%, and the rCBF and right/left (R/L) ratios of each brain region were calculated. Second, brain metabolism imaging 1. Brain glucose metabolism shows that glucose is almost the only energy substance in brain tissue. 18F-FDG is a glucose analog with the same cellular transport and glycosylation phosphorylation process as glucose, but it is no longer involved in the further metabolism of glucose and is retained in brain cells after conversion to 18F-FDG-6-P. The subjects were fasted for more than 4 hours, and PET or SPECT/PET brain glucose metabolism imaging was performed 45-60 min after intravenous injection of 18F-FDG 185-370 MBq. The regional brain glucose metabolic rate (LCMRglu) and whole brain glucose metabolic rate (CMRglu) were calculated in various parts of the brain. 2. Brain oxygen metabolism imaging The normal human brain weighs only 2% of the body weight, but its oxygen consumption accounts for 20% of the whole body. Therefore, brain oxygen consumption is an important reference index reflecting the functional metabolism of the human brain. The patient's dynamic imaging of PET immediately after inhalation of 15O2 can obtain the cerebral oxygen metabolism rate (CMRO2), and the oxygen uptake score (OEF) can be calculated in combination with the CBF measurement. 3. Brain protein metabolism imaging using 11C-MET (11C-methyl-L-methionine), 11C-TYR (11C-tyrosine), 18F-FET (18F-fluoroethyl tyrosine) and 123I- IMT (123I-iodomethyltyrosine) or the like can be used as an imaging agent to obtain an image reflecting the function of amino acid uptake and protein synthesis in the brain. Third, central neurotransmitter and receptor imaging: specific ligands labeled with radionuclides, in view of receptor-ligand-specific binding properties, precise localization of specific receptor binding sites at the level of living human brain and obtained Receptor distribution, density, and affinity imaging; the use of radiolabeled precursors of synthetic neurotransmitters to observe specific central neurotransmitter synthesis, release, binding to postsynaptic membrane receptors, and reuptake. Radionuclide cerebrovascular imaging: specific ligands labeled with radionuclides, in view of receptor-ligand-specific binding properties, precise localization of specific receptor binding sites and acquisition of receptors at the level of living human brain Distribution, density, and affinity images; the use of radiolabeled synthetic neurotransmitter precursors allows for the observation of specific central neurotransmitter synthesis, release, binding to postsynaptic membrane receptors, and reuptake. Not suitable for the crowd Inappropriate crowd: First, cerebral blood flow imaging: patients who are allergic to potassium perchlorate and imaging agents. Second, brain metabolism imaging: pregnant women, emotional instability or persistent sputum are prohibited. Third, central neurotransmitter and receptor imaging and radionuclide cerebrovascular imaging. 1. Those with a history of severe allergies. 2. For patients suspected of severe pulmonary vascular bed damage and severe pulmonary hypertension. 3, severely impaired kidney function, severe edema. Adverse reactions and risks Nothing.