心脏磁共振成像(MRI)

什么是心脏MRI?

A cardiac MRI is a noninvasive test that uses a magnetic field and radiofrequency waves to create detailed pictures of your heart and arteries.

为什么人们要做心脏核磁共振?

A cardiac MRI is usually requested if someone has more advanced or complex heart conditions. They are often referred after initial first-line testing, such as transthoracic 超声心动图.

It can be used to look at blood vessels and how blood flows through them, how much blood the left ventricle can pump out to the body and measure heart function.

A cardiac MRI can help your health care team diagnose many different heart conditions, such as:

• 组织损伤 心脏病.
• Reduced blood flow in the heart muscle to help determine whether heart artery blockages (ischemia) are the cause of your chest pain (angina).
• 炎症 myocardium即心脏壁的中间肌肉层.
• 存在的问题 aorta — the heart’s main artery — such as a tear, aneurysm (bulge) or narrowing.
• Diseases of the pericardium (outer lining of the heart muscle) such as constrictive 心包炎.
• 心脏肌肉疾病，如 心肌病, 心脏衰竭 心脏肿瘤.
• 心脏瓣膜紊乱如反流和狭窄.
• 先天性心脏病 以及手术修复的成功.

心脏核磁共振检查有哪些风险?

心脏核磁共振对大多数人来说是一种安全无痛的检查. People with any type of metal device inside their body shouldn’t have a cardiac MRI unless the device is certified as MRI safe. 这些装置可能包括:

• Pacemakers and 植入式转复除颤器.
• 内耳(耳蜗)植入物.
• Neuromuscular stimulators, such as those used for pain management or muscle rehabilitation.
• 植入式药物输注泵.
• 一些宫内节育器(iud).
• 未被核磁共振批准的脑动脉瘤夹.
• Some dental implants (check with your dentist to make sure they aren’t magnetic).

The MRI staff will ask you to complete a detailed questionnaire to help them determine if you have anything in your body that would prevent you from having an MRI. You should avoid cardiac MRI if you have metal fragments in your body. Metal fragments in the eyes can be especially dangerous because the magnet may move the metal, 造成眼睛损伤或失明的.

For some cardiac MRIs, a special contrast dye (without iodine) may be used. This contrast dye is not usually given to people with advanced kidney failure. If you have kidney problems, your health care team will measure your kidney function before the test.

Check with your health care team about the safety of a cardiac MRI if you:

• Have a stent or artificial heart valve, or if you have had open-heart surgery recently.
• 怀孕了吗，尤其是头三个月.
• 有纹身或永久性的(纹身)化妆吗. You might feel some mild discomfort or a burning feeling on your skin from the metal in the darker inks of the tattoo.
• 有人告诉你有肾脏问题吗.

如何准备心脏核磁共振检查?

• 在心脏核磁共振检查之前, eat normally and take your usual medicines unless your health care professional tells you not to.
• It’s very important to remove all objects that may contain metal or electronics before the test, 比如戒指或耳环, hairpins, dentures, 手表和助听器.
• 不要把你的信用卡或借记卡带进核磁共振室. The machine might erase or damage the magnetic strip on the back of the cards.
• 如果你体内有植入物或夹子, have your health care professional write a note to indicate if they are safe for MRI.

核磁共振检查会发生什么?

A radiologist or MRI technologist usually performs the scan in a hospital, 诊所或影像中心使用特殊设备.

• 你躺在一张可以滑动到核磁共振成像仪的桌子上. 这台机器看起来像一根长长的金属管.
• You’ll need to lie still during the exam because movement can blur the images.
• 你的技术人员会在另一个房间看着你. 你可以通过麦克风对他们讲话.
• The MRI machine will create a strong magnetic field around you, and radio waves will be directed at the area of your body to be imaged.
• During the MRI, the magnet produces loud tapping or thumping sounds and other noises. You may be given earplugs or you may listen to music with headphones to help block the noise.
• You might have an intravenous line in your hand or arm for injecting a contrast agent into your veins (for magnetic resonance angiography). This produces better images of your tissues and blood vessels.
• 核磁共振成像通常持续30到90分钟.

If you aren’t comfortable in close spaces, tell your health care professional before the test. 他们可能会开镇静剂来帮助你保持冷静. Some clinics have machines with shorter magnets or wider openings to make you more comfortable.

核磁共振后会发生什么?

You can usually go back to your normal activities right away.

• If you had a sedative, you’ll stay at the MRI center until the effects wear off. 你还需要有人开车送你回家.
• The radiologist will review the images and send your health care team a copy of the report so they can discuss the test results with you.