胸部CT

定义

A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen.

选择的名字

Thoracic CT; CT scan - lungs; CT scan - chest

如何执行测试

测试方法如下:

• You'll likely be asked to change into a hospital gown.
• You lie on a narrow table that slides into the center of the scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you.
• You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short period of time.

The complete scan takes 30 seconds to a few minutes.

某些 CT扫描 require a special dye, called contrast, to be delivered into the body before the test starts. Contrast highlights specific areas inside the body and creates a clearer image. If your provider requests a CT scan with intravenous contrast, you will be given it through a vein (IV) in your arm or hand. A blood test to measure your kidney function may be done before the test. This test is to make sure your kidneys are healthy enough to filter the contrast.

You may be given medicine to help you relax during the test.

如何准备考试

Some people have allergies to IV contrast and may need to take medicine before their test to safely receive this substance.

如果使用对比, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.

如果你的体重超过300磅(135公斤), have your health care provider contact the scanner operator before the exam. CT scanners have an upper weight limit of 450 pounds (204 kilograms). Some newer scanners can accommodate up to 680 pounds (308 kilograms). Because it is hard for x-rays to pass through metal, you will be asked to remove jewelry.

考试的感觉如何

Some people may have discomfort from lying on the hard table.

Contrast given through an IV may cause a slight burning sensation, 嘴里有金属的味道, 还有温暖的身体潮红. These sensations are normal and usually go away within a few seconds.

There is no recovery time, unless you were given medicine to relax. After a CT scan, you can go back to your normal diet, activity, and medicines.

为什么要进行测试

CT可以快速生成详细的身体图像. The test may be used to get a better view of the structures inside the chest. A CT scan is one of the best ways of looking at soft tissues such as the heart and lungs.

可以做胸部CT:

• 胸部受伤后
• 当一个 肿瘤 or mass (clump of cells) is suspected, including a 孤立性肺结节 胸部x光片
• To determine the size, shape, and position of organs in the chest and upper abdomen
• 寻找 bleeding or fluid collections in the lungs or other areas
• 检查胸部是否有感染或炎症
• 检查肺部是否有血块
• 寻找肺部的疤痕
• 寻找 肺气肿

异常结果意味着什么

Thoracic CT may show many disorders of the heart, lungs, mediastinum, or chest area, including:

• A 墙上的裂缝, an 膨胀不正常的扩大或膨胀, or 缩小 of the major artery carrying blood out of the heart (aorta)
• Other abnormal changes of the major blood vessels in the lungs or chest such as blood clots (pulmonary embolism)
• 累积的 心脏周围有血液或液体
• 肺癌或 扩散到肺部的癌症 从身体的其他部位
• Collection of fluid around the lungs (pleural effusion)
• Damage to, and widening of the large airways of the lungs (支气管扩张)
• 淋巴结肿大
• Lung disorders in which lung tissues become inflamed and then damaged (肠道肺病)
• 肺炎
• 食道癌
• 胸部淋巴瘤
• 胸部的肿瘤、结节或囊肿

风险

CT扫描 and other x-rays are strictly monitored and controlled to make sure they use the least amount of radiation. CT扫描使用低水平的电离辐射, which has the potential to cause cancer and other defects. 然而，任何一次扫描的风险都很小. 随着越来越多的研究完成，风险也在增加.

The most common type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, 恶心想吐, 打喷嚏, 呕吐, 瘙痒, 或者可能出现荨麻疹. In rare cases, the dye can cause a life-threatening allergic response called anaphylaxis. 如果你在考试中呼吸困难, 你应该立即通知扫描仪操作员. Scanners come with an intercom and speakers, so the operator can hear you at all times.

In people with kidney problems, the dye may have harmful effects on the kidneys. In these situations, special steps may be taken to make the contrast dye safer to use.

In spite of its risks, a CT scan may still be done if the benefits greatly outweigh the risks. For example, it can be more risky to not have the exam if your provider thinks you might have cancer.

参考文献

Nair A, Barnett JL, Semple TR. 胸部影像学的现状. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. 格兰杰 & 艾利森诊断放射学. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 1.

王晓明，王晓明，王晓明，等. 安全使用造影剂. 见:Abujudeh HH, Bruno MA，编. 放射学非解释技能:必备十大赌博靠谱网络平台. Philadelphia, PA: Elsevier; 2018:chap 20.