胸部核磁共振

定义

A chest MRI (magnetic resonance imaging) scan is an imaging test that uses powerful magnetic fields and radio waves to create pictures of the chest (thoracic area). 它不使用辐射(x射线).

选择的名字

Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI

如何执行测试

测试方法如下:

• You may be asked to wear a hospital gown or clothing without metal fasteners (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images or be dangerous to have on in the scanner room.
• You lie on a narrow table, which slides into the large tunnel-shaped scanner.
• 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.

一些检查需要一种叫做对比剂的特殊染料. The dye is usually given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly. A blood test to measure your kidney function may be done before the test. This is to make sure your kidneys are healthy enough to filter the contrast.

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 it 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 provider if you are claustrophobic (afraid of closed spaces). 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 your body.

Before the test, tell your health care provider if you have:

• 脑动脉瘤 剪辑
• 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 are on dialysis (you may not be able to receive contrast)
• 最近放置的人工关节
• 血管 支架
• Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes)

The MRI contains strong magnets, so metal objects are not allowed into the room with the MRI scanner. This is because there is a risk that they will be drawn from your body toward the scanner. 你需要清除的金属物品有:

• 钢笔、小刀和眼镜
• Items such as jewelry, watches, credit cards, and hearing aids
• 别针、发夹和金属拉链
• 可移动牙科手术

Some of the newer medical devices described above are MRI compatible, so the radiologist needs to check the device manufacturer to determine if an MRI is possible.

考试的感觉如何

核磁共振检查不会引起疼痛. If you have trouble lying still or are very nervous, you may be given medicine to relax. Too much movement can blur MRI images and cause errors when the doctor looks at the images.

The table may be hard or cold, but you can ask for a blanket or pillow. The machine produces loud thumping and humming noises when turned on. 你可以戴上耳塞来减少噪音.

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

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

为什么要进行测试

A chest MRI provides detailed pictures of tissues within the chest area. 一般来说，它在观察肺部方面不如 胸部CT扫描但对其他组织可能更好.

胸部MRI可用于:

• 提供替代方案 血管造影术，或避免反复暴露在辐射中
• 澄清先前的发现 x射线 或者CT扫描
• 诊断胸部的异常生长
• 评估血流量
• 显示淋巴结和血管
• 从多个角度展示胸部的结构
• See if cancer in the chest has spread to other areas of the body (this is called staging -- it helps guide future treatment and follow-up, 并让你知道未来会发生什么)
• Detect tumors, especially in the middle part of the chest (mediastinum)

正常的结果

正常的结果意味着你的胸部看起来正常.

异常结果意味着什么

胸部MRI异常可能是由于:

• A 墙上的裂缝, an 膨胀不正常的扩大或膨胀, or narrowing of the major artery carrying blood out of the heart (aorta)
• Other abnormal changes of the major blood vessels in the 肺 or chest
• 累积的 心脏周围有血液或液体 (心包积液)或 肺 (胸腔积液)
• 肺癌或 扩散到肺部的癌症 从身体的其他部位
• 心脏的癌症或肿瘤
• 胸腺癌胸部的癌症或肿瘤，如胸腺肿瘤
• Disease in which the heart muscle becomes weakened, stretched, or has another structural problem (心肌病)
• Damage to, and widening of the large airways of the 肺 (bronchiectasis)
• 淋巴结肿大
• 心脏组织或心脏瓣膜感染
• 食道癌
• 胸部淋巴瘤
• 先天性心脏缺陷
• 胸部的肿瘤、结节或囊肿

风险

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

最常用的造影剂(染料)是钆. 它很安全. 对这种物质的过敏反应很少发生. However, gadolinium can be harmful to people with kidney problems who need dialysis. If you have kidney problems, tell your provider before the test.

The strong magnetic fields created during an MRI can cause heart 起搏器s and other implants not to work as well. It can also cause a piece of metal inside your body to move or shift.

注意事项

目前, MRI is not considered a valuable tool for spotting or monitoring slight changes in lung tissue. 肺部主要含有空气，很难成像. CT扫描往往更适合监测这些变化.

MRI的缺点包括:

• 高成本
• 扫描的长度
• 对运动的敏感性

参考文献

阿克曼JB. Thoracic magnetic resonance imaging: technique and approach to diagnosis. 见:Shephard J-AO编. Thoracic Imaging:必备欧洲杯竞猜网站入口. 3日艾德. Philadelphia, PA: Elsevier; 2019:chap 3.

Jokerst CE, Gotway MB. 胸部放射学:无创诊断成像. 见:broadus VC, Ernst JD, King TE等编. 默里和纳德尔的呼吸医学教科书. 7日艾德. Philadelphia, PA: Elsevier; 2022:chap 20.