The brain can be divided into the cerebrum, brainstem, and cerebellum:

• Cerebrum. 大脑(幕上或大脑前部)是 由左右半球组成的. Functions of the 大脑包括:发起运动、协调运动 运动，温度，触觉，视觉，听觉，判断， 推理，解决问题，情感和学习.

• Brainstem. 脑干(脑中线或正中)包括 the midbrain, the pons, and the medulla. Functions of this area 包括:眼睛和嘴的运动，感官的传递 messages (hot, pain, loud, etc.), hunger, respirations, consciousness, cardiac function, body temperature, involuntary muscle movements, sneezing, coughing, vomiting, and swallowing.

• Cerebellum. 小脑(幕下或脑后部)是 located at the back of the head. Its function is to coordinate 自主肌肉运动，保持姿势，平衡， and equilibrium.

More specifically, other parts of the brain include the following:

• Pons. 大脑深处的一部分，位于脑干 脑桥包含许多眼睛和脸部的控制区域 动作，面部感觉，听觉和平衡.

• Medulla. 脑干的最低部分，髓质是 整个大脑最重要的部分，包含着重要的 control centers for the heart and lungs.

• Spinal cord. 脊椎骨位于背部的一大束神经纤维 that extends from the base of the brain to the lower back, the spinal cord carries messages to and from the brain and the rest of the body.

• Frontal lobe. 大脑中最大的部分位于 front of the head, the frontal lobe is involved in personality characteristics and movement.

• Parietal lobe. 大脑的中间部分，顶叶 帮助一个人识别物体和理解空间 relationships (where one's body is compared to objects around the person). 顶叶也参与翻译 pain and touch in the body.

• Occipital lobe. The occipital lobe is the back part of the brain that is involved with vision.

• Temporal lobe. 大脑的两侧，这些颞叶是 与记忆、语言和嗅觉有关的.

脑部CT扫描的原因是什么?

A CT of the brain may be performed to assess the brain for tumors and other lesions, injuries, intracranial bleeding, structural anomalies (e.g., hydrocephalus , infections, brain function or other conditions), particularly when another type of examination (e.g., X-rays or a physical exam) are inconclusive.

A brain CT may also be used to evaluate the effects of treatment on brain tumors 并检测大脑中的凝块，这可能是导致 strokes . Another use of brain CT is to provide guidance for brain surgery or biopsies of brain tissue.

There may be other reasons for your doctor to recommend a CT of the brain.

脑部CT扫描有什么风险?

You may want to ask your doctor about the amount of radiation used during the brain CT procedure and the risks related to your particular situation. 你应该把你过去的辐射史记录下来 exposure, such as previous CT scans and other types of X-rays, so that you can inform your doctor. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time.

To safeguard your health, consider the following precautions before scheduling a brain CT:

• Pregnancy : If you are pregnant or suspect that you may be pregnant, you should notify your doctor. Radiation exposure during pregnancy may lead to birth defects. If it is necessary for you to have a CT of the brain, special precautions will be made to minimize the radiation exposure to the fetus. Contrast media: If contrast media is used 在做脑部CT时，推荐十大正规网赌平台可能会出现过敏反应 reaction to the media. Some patients should not have an iodine-based contrast media. Patients who are allergic to or 对药物敏感者应告知医生. When you 安排你的脑部CT扫描，你应该通知医院 center representative if you have had an allergic reaction to 是否有造影剂或者你是否有肾衰竭之类的 kidney problems. 静脉造影剂不会被使用，如果你 是否对造影剂有严重或过敏反应 media in the past. You may be able to have the scan performed 没有造影剂或有替代成像检查. . A 报告的海鲜过敏不被认为是一种 contraindication for iodinated contrast. Nursing mothers may 注射造影剂后要等待24小时 before resuming breastfeeding.

• Diabetes: Patients taking the diabetes medication metformin (Glucophage) 在做静脉造影前应该提醒医生吗 因为它可能会引起一种罕见的代谢疾病 acidosis. 如果你服用了二甲双胍，医生会要求你停止服用 taking it at the time of the procedure and wait 48 hours after 重新开始用药前的程序. A blood test to check kidney function may be required before you can resume taking metformin.

There may be other risks depending on your specific medical condition. 检查前一定要和你的医生讨论任何问题 procedure.

我该如何准备脑部CT扫描?

If you are having computed tomography angiography (CTA) ，当你作出决定时，你会得到具体的指示 appointment. 以下说明将帮助您准备您的 brain CT:

• Clothing 你可能会被要求换上病号服. If so, a gown will be provided for you. Please remove all piercings and leave all jewelry and valuables at home.

• Contrast media: You will be asked to sign a consent form that will detail the risks and side-effects associated with contrast media injected 通过一根小管子插在静脉里叫做静脉注射 (IV) line. 最常见的脑CT扫描类型 is the double-contrast study that will require you to drink a 除了静脉注射外，还要在检查前补充造影剂 contrast. 如果你过去有轻度到中度的反应， you will likely need to take medication prior to the brain CT scan.

• Food and drink : If your doctor ordered a brain CT scan without contrast, you can eat, drink and take 检查前的处方药物. If your doctor ordered a CT of the brain with contrast, do not eat anything three hours prior to your brain CT. You are encouraged to drink clear liquids.

• Diabetics : Diabetics should eat a light breakfast or lunch three hours prior to the scheduled scan. Depending on your oral medication for diabetes, you may be asked to discontinue the use of your medication for 48 hours afterthe brain CT scan. 如果你在约翰霍普金斯大学放射科做过CT扫描， detailed instructions will be given following your examination.

• Medication : All patients can take their prescribed medications as usual, unless otherwise directed.

Based on your medical condition, your doctor may request other specific steps for brain CT preparation.

Brain CT scans may be performed on an outpatient basis or as part of your hospital stay. 程序可能会根据你的情况而有所不同 your physician's practices.

一般来说，脑部CT扫描包括以下步骤:

• If you having a procedure done with contrast, an IV line will be started in the hand or arm for the injection of the contrast media. 口腔造影剂是液体造影剂 preparation to swallow.

• You will lie on a scan table that slides into a large, circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.

• 技师会在另一个房间，扫描仪 controls are located. However, you will be in constant sight of the technologist through a window. Speakers inside the scanner will enable two-way communication between the technologist and the patient. 您可能有一个呼叫按钮，这样您就可以让 技术人员会知道您在操作过程中是否有任何问题 procedure. 技师会一直看着你的 and will be in constant communication.

• 当扫描仪开始围绕你旋转时，x射线就会通过 through the body for short amounts of time. You will hear clicking sounds, which are normal.

• The X-rays absorbed by the body's tissues will be detected by 扫描并传送到计算机. The computer will 将信息转换成图像，由 the radiologist.

• 在手术过程中你必须保持不动. You may be 要求在不同的时间屏住呼吸 procedure.

• If contrast media is used for your procedure, you may feel some 当介质注入静脉管时的影响. These effects include a flushing sensation, a salty or metallic taste 在你的嘴里，短暂的头痛或恶心和/或呕吐. 这些影响通常会持续几分钟.

• 如果你遇到任何问题，你应该通知技术人员 呼吸困难，出汗，麻木或心脏 palpitations.

• When the procedure has been completed, you will be removed from the scanner.

• 如果静脉注射造影剂 line will be removed.

While the brain CT itself causes no pain, having to lie still for the 手术时间过长可能会引起一些不适或疼痛， particularly in the case of a recent injury or invasive procedure (e.g. surgery). 技术人员将使用所有可能的舒适措施 complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after a CT of the brain?

If contrast media was used during your brain CT scan, you may be monitored for a period of time to check for any side effects or reactions to the contrast media. Notify your radiologist or if you 感到瘙痒、肿胀、皮疹或呼吸困难. If you notice any pain, redness and/or swelling at the IV site after you return home following your procedure, you should notify your doctor as 这可能表明感染或其他类型的反应.

Otherwise, there is no special type of care required after a CT of the brain. 大多数推荐十大正规网赌平台被允许恢复正常饮食 activities. 你的医生可能会提供额外的或替代的 instructions after the procedure, depending on your particular situation.