腿部MRI扫描

定义

A leg MRI (magnetic resonance imaging) scan of the leg uses strong magnets to create pictures of the leg. This may include the ankle, foot, and surrounding tissues.

腿部核磁共振成像也会产生 膝盖图片.

核磁共振成像不使用辐射(x射线).

单个MRI图像称为切片. The images can be stored on a computer or printed on film. 一次检查产生许多切片.

选择的名字

MRI - lower extremity; Magnetic resonance imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg

如何执行测试

You will be asked to wear a hospital gown or clothes without metal zippers or snaps (such as sweatpants and a t-shirt). Make sure you take off your watch, jewelry and wallet. 核磁共振成像可以拉出任何金属物体. 某些类型的金属会导致图像模糊.

You will lie on a narrow table that slides into a tunnel-like scanner.

一些检查使用一种特殊的染料(造影剂). Most of the time, you will get the dye through a vein in your arm or hand before the test. 有时，染料被注入关节. The dye helps the radiologist see certain areas more clearly.

During the MRI, the person who operates the machine will watch you from another room. The test most often lasts 30 to 60 minutes, but may take longer.

如何准备考试

You may be asked not to eat or drink anything for 4 to 6 hours before the scan.

Tell your health care provider if you are afraid of closed spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close to the body.

在测试前，告诉你的十大赌博平台排行榜你是否有:

• 脑动脉瘤夹
• 某些类型的人工心脏瓣膜
• 心脏除颤器或起搏器
• 内耳(耳蜗)植入物
• Kidney disease or dialysis (you may not be able to receive contrast)
• Recently placed artificial joints or surgery with metal plates and screws
• 某些类型的血管 支架
• Worked with sheet metal (you may need tests to check for metal pieces in your eyes)

因为核磁共振成像含有强磁铁, metal objects are not allowed into the room with the MRI scanner:

• Pens, pocketknives, and eyeglasses may fly across the room.
• Items such as jewelry, watches, credit cards, and hearing aids can be damaged.
• Pins, hairpins, metal zippers, and similar metallic items can distort the images.
• Removable dental work should be taken out just before the scan.

考试的感觉如何

核磁共振检查不会引起疼痛. 你需要安静地躺着. Too much movement can blur MRI images and cause errors.

The table may be hard or cold, but you can ask for a blanket or pillow. The machine makes loud thumping and humming noises when turned on. You can wear ear plugs to help block out the noise.

An intercom in the room allows you to speak to someone at any time. Some MRIs have televisions and special headphones to help the time pass.

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

为什么要进行测试

This test provides detailed pictures of parts of the leg that are hard to see clearly on CT scans.

Your provider may order an MRI of the leg if you have:

• 肿块:在体检中可以摸到的肿块
• x光或骨扫描的异常发现
• 先天缺陷腿、脚踝或脚的先天缺陷
• 骨痛和发烧
• 骨折
• 踝关节活动减少
• 腿部疼痛、肿胀或发红
• 踝关节发红或肿胀
• 腿部疼痛和癌症病史
• Leg, foot, or ankle pain that does not get better with treatment
• 脚踝和脚不稳定

正常的结果

A normal result means your leg has no identified problems.

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
• 阿基里斯肌腱炎
• 关节炎
• 骨折或骨折
• 骨骼感染
• 韧带、肌腱或软骨损伤
• 肌肉损伤
• 骨坏死(缺血性坏死)
• 足底筋膜破裂(见: 足底筋膜炎)
• 胫后肌腱功能障碍
• Tear or rupture of the Achilles tendon in the ankle area
• Tumor or cancer in the bone, muscle, or soft tissue

Talk to your provider about your questions and concerns.

风险

核磁共振成像不使用辐射. There have been no reported side effects from the magnetic fields and radio waves.

It is also safe to have MRI performed during pregnancy. 没有任何副作用或并发症被证实.

The most common type of contrast (dye) used is gadolinium. 它很安全. 很少有过敏反应. However, gadolinium can be harmful to people with kidney problems that need dialysis. If you have kidney problems, please tell your provider before the test.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause a piece of metal inside your body to move or shift. For safety reasons, please do not bring anything that contains metal into the scanner room.

注意事项

Tests that may be done instead of an MRI include:

• 骨扫描
• 腿部的CT扫描
• 正电子发射断层扫描(PET)扫描
• 腿部x光片

在紧急情况下，首选CT扫描. The test is faster than MRI and often available in the emergency room.

参考文献

Kadakia AR, Aiyer AA. 足部和踝关节成像. 见:米勒博士，汤普森博士，编辑. 口腔、Drez & 米勒的骨科运动医学. 5日艾德. Philadelphia, PA: Elsevier; 2020:chap 112.

Kapoor G, tom AP. Current status of imaging of the musculoskeletal system. 在:亚当A，迪克森AK，吉拉德JH， Schaefer-Prokop CM编. 格兰杰 & 艾利森诊断放射学. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 38.

陈建军，陈建军，陈建军. 脚和脚踝. 见:Haaga JR, Boll DT编. 全身CT和MRI. 6日艾德. Philadelphia, PA: Elsevier; 2017:chap 64.