What is a cranial CT scan?

头颅CT扫描是诊断工具用于create detailed pictures of features inside your head, such as your skull, brain, paranasal sinuses, ventricles, and eye sockets. CT stands for computed tomography, and this type of scan is also referred to as a CAT scan. A cranial CT scan is known by a variety of names as well, including brain scan, head scan, skull scan, and sinus scan.

This procedure is noninvasive, meaning it doesn’t require surgery. It’s usually suggested to investigate various symptoms involving the nervous system before turning to invasive procedures.

颅CT扫描创建的图片比常规的图片更详细X射线。他们可以帮助诊断一系列疾病，包括：

  • 头骨骨头的异常
  • arteriovenous malformation, or abnormal blood vessels
  • atrophy of brain tissue
  • birth defects
  • 脑动脉瘤
  • 大脑出血或流血
  • 脑积水, or fluid buildup in your skull
  • infections or swelling
  • injuries to your head, face, or skull
  • stroke
  • tumors

Your doctor may order a cranial CT scan if you’ve had an injury or display any of these symptoms with no apparent cause:

  • fainting
  • headache
  • seizures，特别是如果最近发生
  • 突然的行为变化或思维变化
  • 听力损失
  • vision loss
  • muscle weakness or numbness and tingling
  • 语音困难
  • 吞咽困难

A cranial CT scan can also be used to guide other procedures such as surgery or biopsy.

A cranial CT scanner takes a series of X-rays. A computer then puts these X-ray images together to create detailed pictures of your head. These images help your doctor make a diagnosis.

该过程通常在医院或门诊成像中心进行。完成扫描只需要大约15分钟。

On the day of the procedure, you must remove jewelry and other metal objects. They can damage the scanner and interfere with the X-rays.

您可能会被要求换成医院礼服。根据您的CT扫描的原因，您会躺在狭窄的桌子上。

It’s very important that you remain completely still during the exam. Even a little movement can blur the images.

Some people find the CT scanner stressful or claustrophobic. Your doctor may suggest a sedative to keep you calm during the procedure. A sedative will also help keep you still. If your child is having the CT scan, their doctor may recommend a sedative for these same reasons.

桌子会慢慢滑动，使您的头部在扫描仪内部。可能会要求您在短时间内屏住呼吸。扫描仪的X射线梁将围绕您的头部旋转，从不同角度创建一系列头部图像。单个图像称为切片。堆叠切片会创建三维图像。

Images can be seen immediately on a monitor. They will be stored for later viewing and printed. For your security, the CT scanner has a microphone and speakers for two-way communication with the scanner operator.

Contrast dye helps highlight some areas better on CT images. For example, it can highlight and emphasize blood vessels, intestines, and other areas. The dye is given through an intravenous line inserted into a vein of your arm or hand.

通常，图像首先是没有对比度的，然后再次与对比度拍摄。但是，使用造影剂染料并不总是必要的。这取决于您的医生要寻找的东西。

如果您要接受对比染料，您的医生可能会指示您在测试前几个小时不要吃或喝酒。这取决于您的特定医疗状况。向您的医生咨询CT扫描的具体说明。

The scanner table is very narrow. Ask if there is a weight limit for the CT scanner table if you weigh more than 300 pounds.

请务必告诉医生您是否怀孕。不建议孕妇使用任何形式的X射线。

如果使用对比度染料，您将需要注意一些额外的预防措施。例如，必须对糖尿病药物二甲双胍（葡萄糖量）的人采取特殊措施。请务必让您的医生知道您是否服用这种药物。还要告诉医生您是否曾经对对比染料产生不利反应。

Side effects and risks for a cranial CT scan involve discomfort, exposure to radiation, and allergic reaction to the contrast dye.

测试前与您的医生讨论任何问题，以便您可以评估医疗状况的潜在风险和益处。

Discomfort

CT扫描本身是无痛的程序。有些人在坚硬的桌子上感到不舒服，或者仍然难以保持困难。

当对比染料进入静脉时，您可能会感到有些燃烧。有些人的嘴里经历了金属味，并且整个身体都有温暖的感觉。这些反应是正常的，通常持续不到一分钟。

辐射暴露

CT scans expose you to some radiation. Doctors generally agree that the risks are low compared to the potential risk of not being diagnosed with a dangerous health problem. The risk from a single scan is small, but it increases if you have many X-rays or CT scans over time. Newer scanners may expose you to less radiation than older models.

告诉您的医生，如果您怀孕了。您的医生也许可以避免通过使用其他测试使宝宝接触到辐射。这些可能包括主MRIscan or ultrasound, which don’t use radiation.

Allergic reaction to contrast

在扫描之前，请告诉医生，如果您对对比染料有过敏反应。

Contrast dye commonly contains iodine and may cause nausea, vomiting, rash, hives, itching, or sneezing in people who are allergic to iodine. You may be given steroids or antihistamines to help with these symptoms before you receive the dye injection. after the test, you may need to drink extra fluids to help flush the iodine from the body if you havediabetes或肾脏疾病。

In very rare cases, contrast dye can causeanaphylaxis，一种可以威胁生命的全身过敏反应。如果您呼吸困难，请立即通知扫描仪操作员。

测试后，您应该能够返回正常例程。如果您的测试中使用对比度，您的医生可能会给您特别的指示。

放射科医生将解释测试的结果，并将报告发送给您的医生。扫描以电子方式存储以供将来参考。

Your doctor will discuss the radiologist’s report with you. Depending on the results, your doctor might order more tests. Or if they’re able to reach a diagnosis, they will go over next steps with you, if any.