什么是核磁共振?

磁共振成像, 或核磁共振, is a noninvasive medical imaging test that produces detailed images of almost every internal structure in the human body, 包括器官, 骨头, 肌肉和血管. 核磁共振扫描仪利用一块大磁铁和无线电波对人体进行成像. 与x射线不同，核磁共振检查不会产生电离辐射. These images give your physician important information in diagnosing your medical condition and planning a course of treatment.

在约翰霍普金斯医学影像中心进行核磁共振检查时，你会期待什么

- 关注 你Tube

核磁共振扫描是如何工作的?

核磁共振成像仪很大, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient and sends pulses of radio waves from a scanner. 一些核磁共振成像仪看起来像狭窄的隧道，而另一些则更开放.

The strong magnetic field created by the MRI scanner causes the atoms in your body to align in the same direction. Radio waves are then sent from the MRI machine and move these atoms out of the original position. 因为无线电波被关掉了, 原子回到原来的位置，并发回无线电信号. These signals are received by a computer and converted into an image of the part of the body being examined. 此图像出现在观看监视器上.

核磁共振成像可以代替计算机断层扫描(CT)，当器官或软组织被研究时. MRI is better at telling the difference between types of soft tissues and between normal and abnormal soft tissues.

因为没有使用电离辐射, 在核磁共振过程中没有暴露于辐射的风险.

Newer uses f或核磁共振 have contributed to the development of additional magnetic resonance technology. 磁共振血管造影(MRA) 是否有评估动脉血流的程序. MRA can also be used to detect aneurysms in the brain and vascular malformations — abnormalities of blood vessels in the brain, 脊髓或身体的其他部位.

Functional magnetic resonance imaging (fMRI) of the brain is used to determine the specific location in the brain where a certain function, 比如演讲或记忆, 发生. 大脑中发生这种功能的一般区域是已知的, 但确切的位置可能因人而异. 在大脑的功能磁共振成像中, 你将被要求执行一项特定的任务, 比如背诵效忠誓言. 通过精确定位大脑功能中心的确切位置, 医生可以为脑部疾病计划手术或其他治疗方法.

我该如何准备核磁共振检查?

吃/喝: 在大多数核磁共振检查中，你可以像往常一样吃、喝和服药.  有一些特殊的核磁共振检查需要一定的限制. 你 will be provided detailed preparations instructions by Johns Hopkins 医学成像 when you schedule your exam.

服装: 你 将被要求脱掉所有衣服，包括内衣， 把所有私人物品锁好. 请摘下所有的穿孔，并将所有珠宝和贵重物品留在家中.

期待什么: Imaging takes place inside of a large, tubelike structure that is open on both ends. 为了获得高质量的图像，你必须完全静止不动. Due to the MRI machine's loud noise, earplugs are required and will be provided.

过敏一些核磁共振检查需要静脉造影剂. 如果你对核磁共振造影有过敏反应, 联系您的处方医生以获得推荐的处方. 你 will likely take this by mouth 24, 12 and two hours prior to the examination.

抗焦虑药物: 如果你因为幽闭恐惧症需要抗焦虑药物, 联系你的处方医生. 你必须在预约当天带上你的处方. 请注意，你需要有人开车送你回家.

强磁环境由于强磁场, you must inform your doctor prior to the appointment if you have any metal in your body. 需要详细的资料, 如类型和位置, 来确定你是否有资格做核磁共振. 如果你体内有金属在你预约前没有透露, 你的学习可能会耽误, rescheduled or canceled upon your arrival until more information can be obtained.

Based on your medical condition, your health care provider may require other preparations.

当你打电话预约的时候, it is extremely important that you inform your doctor if any of the following apply to you:

• 你装了心脏起搏器或者换了心脏瓣膜.
• 你有任何类型的植入式泵，比如胰岛素泵.
• 你有血管线圈、过滤器、支架或夹子.
• 你怀孕了，或者觉得自己可能怀孕了.
• 你有过枪伤吗.
• 你曾经接触过金属(例如，作为金属磨床或焊工).
• 你身体各处都有金属碎片.
• 你不能躺下30到60分钟.

我如何准备专门的核磁共振检查?

 在某些情况下, you will be contacted prior to the examination to discuss the details of the procedure and how to prepare.

专门的核磁共振检查包括:

• 乳房核磁共振成像
• 乳房活组织检查 通过核磁共振成像
• MRI动态骨盆/排便造影
• MRI肠造影
• 功能磁共振成像
• 磁共振血管造影(MRA)
• 前列腺MRI成像

在核磁共振检查过程中会发生什么?

MRI scans may be performed on an outpatient basis or as part of a stay in a hospital. 虽然具体的协议可能因设施而异, 核磁共振检查通常遵循这个过程:

• 你会被要求脱掉所有衣服, 珠宝, 眼镜, 助听器, 发夹, 可移动的牙具或其他可能干扰手术的物品.
• 你会得到一件长袍.
• 如果你要做对比手术, an IV line will be started in the hand or arm for injection of the contrast dye. If the contrast is to be taken by mouth, you will be given the contrast to swallow.
• 你 will lie on a scan table that slides into a large circular opening of the scanning machine. 在手术过程中，枕头和带子可以用来防止移动.
• 技术人员将在另一个房间，那里有扫描仪的控制. 然而，你将通过一扇窗户一直看到技术专家. Speakers inside the scanner will enable the technologist to communicate with and hear you. 你 will have a communication ball so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.
• 你 will be given earplugs or a headset to help block out the noise from the scanner. 有些耳机可以播放音乐.
• 扫描过程中, a clicking noise will sound as the magnetic field is created and pulses of radio waves are sent from the scanner.
• 考试时保持不动对你来说很重要, 因为任何移动都可能造成失真，影响扫描质量.
• 时间间隔, 你可能会被指示屏住呼吸或屏住呼吸几秒钟, 取决于被检查的身体部位. 然后你会被告知何时可以呼吸. 你不需要屏住呼吸超过几秒钟.
• If contrast dye is used, you may experience some effects when it is injected into the IV line. 这些影响包括脸红或感觉寒冷, 咸味:口中的咸味或金属味, 短暂的头痛, 瘙痒, 或者恶心和/或呕吐. 这些影响通常会持续几分钟.
• 如果你有呼吸困难，你应该通知技师, 出汗, 麻木或心悸.
• 一旦扫描完成, 桌子会滑出扫描仪，你会被帮助离开桌子.
• If an IV line was inserted for contrast administration, the line will be removed.

而核磁共振成像本身不会引起疼痛, having to lie still for the length of the procedure might cause some discomfort or pain, 特别是如果你最近受过伤或者做过侵入性手术, 比如手术. The technologist will use all possible comfort measures and complete the procedure as quickly as possible.

核磁共振检查后会发生什么?

你 should move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat during the procedure.

If any sedatives were taken for the procedure, you may be required to rest until they have worn off. 你还需要避免开车.

If contrast dye was used during the procedure and you experience any side effects or reactions to the contrast dye, 比如瘙痒, 肿胀, 约会后出现皮疹或呼吸困难，立即打电话给医生. 如果你觉得有生命危险，请拨打911. 

如果你感到疼痛, 回家后静脉注射部位出现红肿, 你应该通知你的医生, 因为这可能表明感染或其他类型的反应.

否则，MRI扫描后不需要任何特殊护理. 你 may resume your usual diet and activities unless your doctor advises you differently.

你r doctor may give you more or alternate instructions after the procedure depending on your particular situation.

如果你是约翰霍普金斯医学院的推荐十大正规网赌平台, you should see a final report on your MRI exam in MyChart three or four days after your appointment. (注意:你必须注册MyChart才能访问你的医疗记录.)

没有麻醉的儿童核磁共振成像-约翰霍普金斯儿科放射学

- 关注 你Tube

你的孩子要做核磁共振检查吗? Kids can learn from Fin the fish everything they need to know about coming to Johns Hopkins for an MRI scan. 你孩子的核磁共振检查可能使用麻醉，也可能不使用麻醉. This video explains the process for having a pediatric MRI scan without anesthesia at Johns Hopkins.