Heart CT scan

Definition

A computed tomography (CT) scan of the heart is an imaging method that uses x-rays to create detailed pictures of the heart and its blood vessels.

• This test is called a coronary calcium scan when it is done to see if you have a buildup of calcium in your heart arteries.
• It is called CT angiography if it is done to look at the arteries that bring blood to your heart. This test evaluates if there is narrowing or a blockage in those arteries.
• 这种测试有时会与脑部扫描结合使用 aorta or 肺动脉 寻找这些结构的问题.

选择的名字

CAT scan - heart; Computed axial tomography scan - heart; Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston score; Coronary calcium scan

如何执行测试

You will be asked to lie on a narrow table that slides into the center of the CT scanner.

• You will lie on your back with your head and feet outside the scanner on either end.
• Small patches, called electrodes are put on your chest and connected to a machine that records your heart's electrical activity. 可能会给你开一些减慢心率的药.
• Once you are inside the scanner, the machine's x-ray beam rotates around you.

A computer creates separate images of the body area, called slices.

• These images can be stored, viewed on a monitor, or printed on film.
• 可以创建心脏的三维模型.

You must be still during the exam, because movement causes blurred images. 你可能会被告知短时间屏住呼吸.

整个扫描应该只需要大约10分钟.

如何准备考试

某些检查需要一种特殊的染料, 叫对比, 在测试开始前被输送到体内. 对比有助于某些区域在x光片上表现得更好.

• Contrast can be given through a vein (IV) in your hand or forearm. 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.

在接受对比之前:

• Let your health care provider know if you have ever had a reaction to contrast or any medicines. You may need to take medicines before the test in order to safely receive this substance.
• 告诉你的十大赌博平台排行榜你服用的所有药物, 因为你可能会被要求拿一些, 如糖尿病药物二甲双胍(Glucophage), 测试前.
• 如果你有肾脏问题，让你的十大赌博平台排行榜知道. 造影剂会导致肾功能恶化.

If you weigh more than 300 pounds (135 kilograms), find out if the CT machine has a weight limit. 重量过大会损坏扫描仪的工作部件.

You will be asked to remove jewelry and wear a hospital gown during the study.

考试的感觉如何

有些人躺在坚硬的桌子上可能会感到不舒服.

静脉注射造影剂可能导致:

• 轻微的灼烧感
• 口中有金属味
• 身体温热潮红

These sensations are normal and usually go away within a few seconds.

为什么要进行测试

CT rapidly creates detailed pictures of the heart and its arteries. 该测试可以诊断或检测:

• Plaque buildup in the coronary arteries to determine your risk for heart disease
• 先天性心脏病 (出生时就有心脏问题)
• 心脏瓣膜有问题
• 心脏供血动脉阻塞
• 心脏肿瘤心脏的肿瘤或肿块
• 心脏的泵送功能

正常的结果

Results are considered normal if the heart and arteries being examined are normal in appearance.

Your "calcium score" is based on the amount of calcium found in the arteries of your heart.

• 如果你的钙评分为0，则测试正常(阴性). This means the chance of having a heart attack over the next several years is very low.
• If the calcium score is very low, you are unlikely to have coronary artery disease.

异常结果意味着什么

异常结果可能是由于:

• Aneurysm
• 先天性心脏病
• 冠状动脉疾病
• 心脏瓣膜问题
• 心脏周围的炎症(心包炎)
• Narrowing of one or more coronary arteries (coronary artery stenosis)
• 肿瘤心脏或周围区域的肿瘤或其他肿块

如果你的钙含量高:

• It means you have calcium buildup in the walls of your coronary arteries. This is usually a sign of atherosclerosis, or hardening of the arteries.
• 你的分数越高，这个问题可能越严重.
• Talk to your provider about lifestyle or other changes you can make to decrease the risk for heart disease.

Risks

CT扫描的风险包括:

• 暴露在辐射中
• 对造影剂过敏

CT扫描确实比普通x光暴露更多的辐射. Having many x-rays or CT scans over time may increase your risk for cancer. 然而，任何一次扫描的风险都很小. You and your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.

有些人对造影剂过敏. Let your provider know if you have ever had an allergic reaction to injected contrast dye.

• 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, 恶心或呕吐, sneezing, itching, or hives may occur.
• 如果你一定要给这样的对比, you may need to take steroids (such as prednisone) or antihistamines (such as diphenhydramine) before the test. You may also need to take a histamine blocker (such as ranitidine).
• 肾脏帮助将碘排出体外. Those with kidney disease or diabetes may need to receive extra fluids after the test to help flush the iodine out of the body.

Rarely, the dye may 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.

References

Blankstein R. 心脏计算机断层扫描. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022: chap 20.

张建军，李建军，李建军，等. ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2019 appropriate use criteria for multimodality imaging in the assessment of cardiac structure and function in nonvalvular heart disease: a report of the American College of Cardiology Appropriate Use Criteria Task Force, 美国胸外科协会, 美国心脏协会, 美国超声心动图学会, 美国核心脏病学会, 心脏节律学会, 心血管血管造影与干预学会, 心血管计算机断层摄影学会, 心血管磁共振学会, 和胸外科学会. 我是科尔·卡迪诺. 2019;73(4):488-516. PMID: 30630640 pubmed.ncbi.nlm.nih.gov/30630640/.

克莱默CM，贝勒GA，哈格斯皮尔KD. 无创心脏显像. 参见:Goldman L, Schafer AI主编. Goldman-Cecil医学. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 50.