虚拟结肠镜检查

定义

虚拟结肠镜检查 (VC) is an imaging or x-ray test that looks for cancer, 息肉, or other disease in the large intestine (colon). 这项检查的医学名称是CT结肠镜检查.

选择的名字

Colonoscopy - virtual; CT colonography; Computed tomographic colonography; Colography - virtual

如何执行测试

VC不同于常规 结肠镜检查. 常规结肠镜检查使用长, lighted tool called a colonoscope that is inserted into the rectum and large intestine.

VC is done in the radiology department of a hospital or medical center. No sedatives are needed and no colonoscope is used.

检查方法如下:

• You lie on your left side on a narrow table that is connected to an 核磁共振成像 or CT 机.
• 你的膝盖向胸部靠拢.
• A small, flexible tube is inserted into the rectum. Air is pumped through the tube to make the colon bigger and easier to see.
• 然后你仰面躺下.
• The table slides into a large tunnel in the CT or 核磁共振成像 机. 给你的结肠拍x光片.
• X-rays are also taken while you lie on your stomach.
• You must stay very still during this procedure, because movement can blur the x-rays. You may be asked to hold your breath briefly while each x-ray is taken.

A computer combines all the images to form three-dimensional pictures of the colon. The doctor can view the images on a video monitor.

如何准备考试

Your bowels need to be completely empty and clean for the exam. A problem in your large intestine that needs to be treated may be missed if your intestines are not cleaned out.

Your health care provider will give you the steps for cleansing your bowel. 这被称为肠道准备. 步骤可能包括:

• 使用灌肠剂
• Not eating solid foods for 1 to 3 days before the test
• 服用泻药

You need to drink plenty of clear liquids for 1 to 3 days before the test. 透明液体的例子有:

• 清咖啡或茶
• 无脂清汤或肉汤
• 明胶
• 运动饮料
• 过滤果汁
• 水

Keep taking your medicines unless your health care provider tells you otherwise.

You will need to ask your provider if you need to stop taking iron pills or liquids a few days before the test, unless your provider tells you it is OK to continue. 铁会使你的大便变黑. This makes it harder for the doctor to view inside your bowel.

CT和核磁共振成像扫描仪对金属非常敏感. 考试当天不戴首饰. You will be asked to change out of your street clothes and wear a hospital gown for the procedure.

考试的感觉如何

x光片是无痛的. Pumping air into the colon may cause cramping or gas pains.

考试后:

• You may feel bloated and have mild abdominal cramping and pass a lot of gas.
• You should be able to return to your regular activities.

为什么要进行测试

风险投资可能出于以下原因:

• 后续在 结肠癌 或息肉
• Abdominal pain, changes in bowel movements, or weight loss
• 贫血 由于铁含量低
• 大便中有血或黑色焦油样大便
• Screen for cancer of the colon or rectum (should be done every 5 years)

Your provider may recommend a regular 结肠镜检查 instead of a VC. The reason is that VC does not allow removing tissue samples 或息肉.

Other times, a VC is done if a regular 结肠镜检查 could not be completed.

正常的结果

Normal findings are images of a healthy intestinal tract.

异常结果意味着什么

Abnormal test results may mean any of the following:

• 结肠直肠癌
• Abnormal pouches on the lining of the intestines, called 憩室病
• 结肠炎 (肿胀和发炎的肠道)由于 克罗恩病, 溃疡性结肠炎感染或血液流动不足
• 下消化道出血
• 息肉
• 肿瘤

Regular 结肠镜检查 may be done (on a different day) after a VC if:

• No cause for bleeding or other symptoms were found. VC可以忽略结肠中一些较小的问题.
• 在VC上发现了需要活检的问题.

风险

风险投资的风险包括:

• 暴露在CT扫描的辐射下
• Nausea, vomiting, bloating, or rectal irritation from medicines used to prepare for the test
• Perforation of the intestine when the tube to pump air is inserted (extremely unlikely).

注意事项

Differences between virtual and conventional 结肠镜检查 include:

• VC可以从许多不同的角度观察冒号. 常规结肠镜检查就不那么容易了.
• VC不需要镇静. You can usually go back to your normal activities right away after the test. Regular 结肠镜检查 uses sedation and often the loss of a work day.
• 使用CT扫描仪的VC会使你暴露在辐射中.
• Regular 结肠镜检查 has a small risk for bowel perforation (creating a small tear). 风险投资几乎没有这种风险.
• VC is often not able to detect 息肉 smaller than 10 mm. Regular 结肠镜检查 can detect 息肉 of all sizes.

参考文献

Garber JJ, Chung DC. 结肠息肉和息肉综合征. 见:Feldman M, Friedman LS, Brandt LJ编. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11日艾德. Philadelphia, PA: Elsevier; 2021:chap 126.

Kim DH, Pickhardt PJ. Computed tomography colonography and evaluation of the colon. 见:戈尔RM，莱文MS，编. 胃肠放射学教科书. 5日艾德. Philadelphia, PA: Elsevier; 2021:chap 38.

李建军，李建军，李建军，等. 结肠直肠癌. In: Niederhuber JE, Armitage JO, Kastan MB, Doroshow JH, Tepper JE, eds. Abeloff临床肿瘤学. 6日艾德. Philadelphia, PA: Elsevier; 2020:chap 74.

Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK. ACG clinical guidelines: colorectal cancer screening 2021. 我是胃肠醇吗. 2021;116(3):458-479. PMID: 33657038 pubmed.ncbi.nlm.国家卫生研究院.gov / 33657038 /.

美国预防服务工作组网站. 最终建议声明. 结直肠癌:筛检. www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening. 2021年5月18日发布. 于2023年3月28日发布.