CT angiography - head and neck

Definition

CT血管造影(CTA)结合了CT扫描和染料注射. CT stands for computed tomography. 这项技术能够创建头部和颈部血管的图像.

Alternative Names

Computed tomography angiography - brain; CTA - skull; CTA - cranial; TIA-CTA head; Stroke-CTA head; Computed tomography angiography - neck; CTA - neck; Vertebral artery - CTA; Carotid artery stenosis - CTA; Vertebrobasilar - CTA; Posterior circulation ischemia - CTA; TIA - CTA neck; Stroke - CTA neck

How the Test is Performed

你将被要求躺在一张狭窄的桌子上，这张桌子滑进了CT扫描仪的中心.

在扫描仪内，机器的x射线束围绕着你旋转.

计算机生成人体区域的许多独立图像，称为切片. 这些图像可以存储，在显示器上观看，或打印在胶片上. 头部和颈部区域的三维模型可以通过将切片堆叠在一起来创建.

考试时你必须保持不动，因为移动会使图像模糊. 你可能会被告知短时间屏住呼吸.

Complete scans usually take only a few seconds. 最新的扫描仪可以在30秒内对你的全身进行从头到脚的扫描.

How to Prepare for the Test

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast helps certain areas show up better on x-rays.

• 造影剂可以通过手或前臂的静脉注射. If contrast is used, 您也可能被要求在测试前4到6小时内不要吃或喝任何东西.
• 让你的医疗保健提供者知道你是否曾经对对比有过反应. 您可能需要在测试前服用药物，以便安全地接受测试.
• Before receiving the contrast, 如果您正在服用糖尿病药物二甲双胍(Glucophage)，请告知您的十大赌博平台排行榜. You may need to take extra precautions.

对于肾功能不佳的人来说，这种对比会加重肾功能问题. 如果你有肾脏问题的历史，和你的十大赌博平台排行榜谈谈.

Too much weight can damage the scanner. 如果你的体重超过300磅(约135公斤), 在测试前和你的十大赌博平台排行榜谈谈体重限制.

在研究过程中，您将被要求摘掉首饰并穿上病号服.

How the Test will Feel

有些人躺在坚硬的桌子上可能会感到不舒服.

If you have contrast through a vein, you may have a:

• Slight burning feeling
• Metallic taste in your mouth
• Warm flushing of your body

这是正常的，通常会在几秒钟内消失.

Why the Test is Performed

头部CTA可用于寻找以下原因:

• Changes in thinking or behavior
• Difficulty pronouncing words
• Dizziness or vertigo
• Double vision or vision loss
• Fainting
• 头痛，当你有某些其他体征或症状时
• Hearing loss (in some people)
• Numbness or tingling, most often on the face or scalp
• Swallowing problems
• Stroke
• Transient ischemic attack (TIA)
• Weakness in one part of your body

CTA of the neck may also be done:

• 颈部外伤后检查血管是否受损
• For planning before carotid artery surgery
• For planning for brain tumor surgery
• 疑似血管炎(血管壁炎症)
• For suspected abnormal blood vessels in the brain

Normal Results

Results are considered normal if no problems are seen.

What Abnormal Results Mean

Abnormal results may be due to:

• Abnormal blood vessels (arteriovenous malformation).
• Bleeding in the brain (for example, subdural hematoma or an area of bleeding).
• Brain tumor or other growth (mass).
• Stroke.
• Narrowed or blocked carotid arteries. 颈动脉为大脑提供主要的血液供应. They are located on each side of your neck.)
• Narrowed or blocked vertebral artery in the neck. (椎动脉为脑后部提供血液.)
• A tear in the wall of an artery (dissection).
• 血管壁的薄弱部位，使血管膨胀或膨胀(aneurysm).

Risks

Risks of CT scans include:

• Being exposed to radiation
• Allergic reaction to the contrast dye
• Damage to the kidneys from the dye

CT scans use more radiation than regular x-rays. 长期进行多次x光或CT扫描可能会增加患癌症的风险. However, the risk from any one scan is small. 你和你的十大赌博平台排行榜应该权衡这种风险和对医疗问题做出正确诊断的好处. 大多数现代扫描仪都采用了减少辐射的技术.

Some people have allergies to contrast dye. 如果你曾经对注射造影剂有过敏反应，让你的十大赌博平台排行榜知道.

• 最常见的静脉造影剂含有碘. If you have an iodine allergy, you may have nausea or vomiting, sneezing, itching, or hives if you get this type of contrast.
• If you absolutely must be given such contrast, 十大赌博平台排行榜可能会在检查前给你开抗组胺药(如苯海拉明)或类固醇.
• The kidneys help remove iodine out of the body. 患有肾脏疾病或糖尿病的人可能需要在测试后接受额外的液体，以帮助将碘排出体外.

这种染料很少会引起危及生命的过敏反应 anaphylaxis. 如果在测试过程中呼吸有困难，请立即告诉扫描仪操作员. 扫描仪配有对讲机和扬声器，因此操作员可以随时听到您的声音.

Considerations

CT扫描可以减少或避免诊断颅骨问题的侵入性手术. 这是研究头部和颈部最安全的方法之一.

其他可以代替头部CT扫描的检查包括:

• MRI of the head
• Positron emission tomography (PET) scan of the head

References

Barras CD, Bhattacharya JJ. 脑成像的现状和解剖特征. 见:Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM，编. Grainger & 艾利森诊断放射学:医学影像教科书. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 53.

Wippold FJ, Orlowski HLP. 神经放射学:神经病理学的替代品. In: Perry A, Brat DJ, eds. 实用外科神经病理学:一种诊断方法. 2nd ed. Philadelphia, PA: Elsevier; 2018:chap 4.