磁共振血管造影

定义

磁共振血管造影 (MRA) is an 核磁共振成像 血管检查. Unlike traditional angiography that involves placing a tube (catheter) into the body, MRA是非侵入性的.

选择的名字

MRA; Angiography - magnetic resonance

如何执行测试

You may be asked to wear a hospital gown. You can also wear clothing without metal fasteners (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.

You will lie on a narrow table, which slides into a large tunnel-shaped scanner.

Some exams require a special dye (contrast). Most often, the dye is given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly.

During the 核磁共振成像, the person who operates the machine will watch you from another room. 测试可能需要1小时或更长时间.

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 close spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious. Your provider may suggest an "open" 核磁共振成像. In open 核磁共振成像, the machine is not as close to the body.

Before the test, tell your provider if you have:

• 脑动脉瘤夹
• 人工心脏瓣膜
• 心脏除颤器 或起搏器
• 内耳(耳蜗)植入物
• 胰岛素泵或化疗端口
• 宫内节育器
• Kidney disease or dialysis (you may not be able to receive contrast)
• 神经
• 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 tiny metal pieces in your eyes)

Because the 核磁共振成像 contains strong magnets, metal objects are not allowed into the room with the 核磁共振成像 scanner. 避免携带下列物品:

• 小刀、钢笔和眼镜
• Watches, credit cards, jewelry, and hearing aids
• Hairpins, metal zippers, pins, and similar items
• 可移动种植体

考试的感觉如何

MRA检查不会引起疼痛. If you have problems lying still or are very nervous, you may be given a medicine (sedative) to relax you. Moving too much can blur images and cause errors.

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. You can wear ear plugs to help reduce the noise.

An intercom in the room allows you to speak to someone at any time. Some scanners 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.

为什么要进行测试

MRA is used to look at the blood vessels in all parts of the body. The test may be done for the head, heart, abdomen, lungs, kidneys, and legs.

It may be used to diagnose or evaluate conditions such as:

• 动脉动脉瘤 (an abnormal widening or ballooning of a part of an artery due to weakness in the wall of the blood vessel)
• 主动脉缩窄
• 主动脉夹层
• 中风
• 颈动脉疾病
• 动脉粥样硬化 胳膊或腿的
• Heart disease, including congenital heart disease
• 肠系膜动脉缺血
• Renal artery stenosis (narrowing of the blood vessels in the kidneys)

正常的结果

A normal result means the blood vessels do not show any signs of narrowing or blockage.

异常结果意味着什么

An abnormal result suggests a problem with one or more blood vessels. 这可能表明:

• 动脉粥样硬化
• 创伤
• 先天性疾病
• 其他血管状况

风险

MRA通常是安全的. 它不使用辐射. To date, no side effects from the magnetic fields and radio waves have been reported.

The most common type of contrast used contains gadolinium. 它很安全. Allergic reactions to the substance rarely occur. However, gadolinium can be harmful to people with kidney problems who require dialysis. If you have kidney problems, please tell your provider before the test.

The strong magnetic fields created during an 核磁共振成像 can cause heart pacemakers and other implants to not work as well. They can also cause a piece of metal inside your body to move or shift.

参考文献

Carpenter JP, Litt H, Gowda M. Magnetic resonance imaging and arteriography In: Sidawy AN, Perler BA, eds. Rutherford's 血管 Surgery and Endovascular Therapy. 10日艾德. Philadelphia, PA: Elsevier; 2023:chap 30.

邝的国家. Cardiovascular magnetic resonance imaging. In: Libby, P, Bonow RO, Mann DL, Tomaselli, GF, Bhatt DL, Solomon SD. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12日艾德. Philadelphia, PA: Elsevier; 2022:chap 19.