手臂CT扫描

定义

A computed tomography (CT) scan of the arm is an imaging method that uses x-rays to make cross-sectional pictures of the arm.

选择的名字

CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm

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.

Once you are inside the scanner, the machine's x-ray beam rotates around you. Modern "spiral" scanners can perform the exam without stopping.

A computer creates separate images of the arm area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of the arm can be created by adding the slices together.

考试时你必须保持安静. 移动会导致图像模糊. You may be told to hold your breath for short periods of time.

The scan should take only 10 to 15 minutes.

如何准备考试

对于一些测试, 你需要一种特殊的染料, 叫对比, to be delivered into the body before the test starts. Contrast helps certain areas show up better on the x-rays.

• 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.
• Let your health care provider know if you have ever had a reaction to contrast. You may need to take medicines before the test in order to safely receive contrast.
• 在接受对比之前, tell your provider if you take the diabetes drug metformin (Glucophage). You may need to take special steps if you are on this medicine.

If you weigh more than 300 pounds (135 kilograms), find out if the CT machine has a weight limit. Too much weight can cause damage to the scanner's working parts.

You will be asked to remove jewelry and wear a hospital gown during the study as metal can affect the CT images.

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. 这些感觉是正常的. 它们会在几秒钟内消失.

为什么要进行测试

CT rapidly creates detailed pictures of the body, including the arms. 该测试可以帮助检测或诊断:

• An 脓肿 或感染
• The cause of pain or other problems in the wrist, shoulder or elbow joints (usually when 核磁共振成像 不可能)
• 骨折
• 肿块和肿瘤，包括癌症
• Healing problems or scar tissue following surgery
• A deformity so the provider can plan appropriate treatment

A CT scan may also be used to guide a surgeon to the right area during a 活组织检查.

正常的结果

Results are considered normal if no problems are seen in the images.

异常结果意味着什么

异常结果可能是由于:

• 由于年龄的增长而发生的退行性变化
• 脓肿(脓液聚集)
• Blood clot in the arm (deep venous thrombosis)
• 骨肿瘤
• 癌症
• 破碎的 或者骨折
• Damage to the hand, wrist, or elbow joints
• 囊肿
• Healing problems or development of scar tissue after surgery
• 生长畸形

风险

CT扫描的风险包括:

• 暴露在辐射中
• 对造影剂过敏
• 如果在怀孕期间造成先天缺陷

CT scans expose you to more radiation than regular x-rays. Having many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any one scan is small. You and your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.

Some people have allergies to contrast dye. 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. A person with an iodine allergy may have nausea or vomiting, 打喷嚏, 瘙痒, 或者荨麻疹，如果给予这种对比.
• If contrast is needed, you may get antihistamines (such as Benadryl) or steroids before the test.
• The kidneys help remove iodine out of the body. Those with kidney disease or diabetes may need to get 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. If you have any trouble breathing during the test, let the scanner operator know right away. Scanners have intercom and speakers so the operator can hear you at all times.

参考文献

Kapoor G, tom AP. Current status of imaging of the musculoskeletal system. 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 38.

佩雷斯EA. Fractures of the shoulder, arm, and forearm. In: Azar FM, Beaty JH，编辑. 坎贝尔整形外科. 14日艾德. Philadelphia, PA: Elsevier; 2021:chap 57.