腿部CT扫描

定义

A computed tomography (CT) scan of the leg makes cross-sectional pictures of the leg. 它使用x射线来产生图像.

选择的名字

CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT扫描 - leg

如何执行测试

You will lie on a narrow table that slides into the center of the CT扫描ner.

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 body area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional (3D) models of the leg can be created by adding the slices together.

You will need to lie still during the exam. 移动会导致图像模糊. You may need to hold your breath for short periods of time.

The scan should take only 10 to 15 minutes.

如何准备考试

Some exams use a special dye, called contrast that is put into your body before the test starts. Contrast helps certain areas show up better on the x射线.

• 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 avoid this problem.
• 在做对比之前, tell your provider if you take the 糖尿病。 medicine metformin (Glucophage). You may need to take extra steps before the test if you take this drug.

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

You will wear a hospital gown during the study. You will need to take off all jewelry as metal can affect the CT images.

考试的感觉如何

Some people may be uncomfortable lying on the hard table.

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

为什么要进行测试

CT扫描 makes detailed pictures of the body very quickly. 该测试可以帮助寻找:

• An 脓肿 或感染
• A mass that is felt during a physical exam
• The cause of pain or other problems in the foot, ankle, or knee joints (usually when an 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 that can be evaluated to help planning for surgery

A CT扫描 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 the leg being examined looks OK.

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
• 脓肿或感染
• 腿部有血块 (深静脉血栓)
• 破碎的 或者骨折
• 癌症
• Damage to the knee, foot, or ankle joint
• 非癌性骨肿瘤
• Healing problems or development of scar tissue after surgery

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扫描s expose you to more radiation than regular x射线. 有许多 x射线 or CT扫描s over time may raise your risk for cancer, but the risk from any one scan is small. Talk to your provider about this risk against the benefits of the test.

Some people have allergies to contrast dye. Let your provider know if you have ever had this type of reaction.

• 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, 或者从这种对比中得到荨麻疹.
• 如果你一定要有这种对比, you may get antihistamines (such as Benadryl) or steroids before the test.
• The kidneys help remove iodine out of the body. 有肾脏疾病的人 糖尿病。 may need to get extra fluids after the test to help flush the iodine out of the body.

The dye may cause a life-threatening allergic response called 速发型过敏反应. 这很罕见. Tell the scanner operator right away if you have any trouble breathing during the test. Scanners come with an 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.

Yepuri N, Pruekprasert N, Cooney RN. 手术并发症. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. 萨比斯顿外科教科书. 21艾德. St Louis, MO: Elsevier; 2022:chap 12.