Myocardial Perfusion Imaging Test
What is a myocardial perfusion imaging test?
心肌灌注成像(MPI)是一种非侵入性成像测试，可以显示血液在心肌中的流动情况. 它可以显示心脏肌肉没有得到足够血液流动的区域. It can also show how well the heart muscle is pumping. This test is often called a nuclear stress test.
There are two types of MPI: single photon emission computed tomography (SPECT) and positron emission tomography (PET).
MPI对胸部不适的人很有用，可以看出疼痛是否是由心脏(冠状动脉)狭窄或阻塞引起的心肌血液流动不足引起的. This type of pain is known as angina. MPI不显示心脏动脉本身，但可以告诉你的医疗保健专业人员是否以及有多少动脉被阻塞. The test can also show if you’ve previously had a heart attack.
如果你有胸痛和异常的MPI测试，下一步可能是执行一个 coronary angiogram (PDF). If the MPI test is normal, 你的健康护理专家会检查你胸痛的其他原因.
Why do people have MPI tests?
MPI测试可以帮助你的医疗保健专业人员发现你是否:
- Have narrowed or blocked heart arteries.
- Have heart damage from a heart attack.
- Should have a coronary angiogram.
- 是否会从冠状动脉支架或搭桥手术中受益，以治疗胸部不适或帮助心脏正常跳动.
The MPI test can also show:
- 如果一个心脏手术(支架，旁路)是有效的，你必须改善血液流动.
- How well your heart can handle physical activity.
If the test is normal, 这意味着没有发现血液流动问题，心脏功能正常. An abnormal result may mean that heart disease is present. 与你的医疗保健专业人员讨论结果，是否需要更多的测试，以及病情有多严重.
What are the risks of an MPI test?
MPI tests are generally safe for most people. MPI studies expose you to a low dose of radiation. 专家们对如此低剂量的辐射是否会致癌持不同意见, but the possibility exists that no dose of radiation, however low, is completely safe. 根据您患心脏病的风险，与您的医疗保健专业人员讨论是否进行该检查. If you’re pregnant or think you might be pregnant, or if you’re a nursing mother, tell your health care professional before you have this test. It could harm your baby.
How do I prepare for my MPI test?
- 告诉你的医疗保健专业人员你服用的任何药物, including over-the-counter medicines, herbs and vitamins. They may ask you not to take them before the test.
- 不要吃某些食物，如含咖啡因的饮料(如咖啡).e.(咖啡、茶和软饮料)或巧克力，如果你被告知不可以的话. 如果你喝了咖啡因，测试可能会被推迟或取消.
- 你可能会被告知在考试前的午夜之后不要吃东西和喝水.
- 穿舒适、宽松的衣服和舒适的鞋子.
What happens during my MPI test?
经过特殊训练的技术人员通常在医院或诊所用特殊设备进行测试.
- 技术人员在你的胸部、手臂和腿上放置小电极. 护垫有电线连接到一台机器上，记录你的心电图(ECG或EKG). 在测试过程中，心电图会记录你的心跳，并告诉相机何时拍照.
- 你会在手臂上戴上一个袖带来记录你的血压.
- The technician will put an intravenous line (IV) in your arm.
- You’ll exercise on either a treadmill or a stationary bicycle.
- If you can’t exercise, 你的静脉注射将连接到一个装有药物的袋子上，该药物可以扩大你的心脏动脉或使其更快, similar to when you exercise. This is called a chemical stress test.
- When you reach your peak activity level, 你会停止并通过静脉注射接受少量放射性物质(示踪剂).
- 你将静静地躺在桌子上10-30分钟，伽玛相机将为你的心脏拍照. 在此期间进行了多次扫描，从各个角度提供整个心脏的薄片图像. 拍照时，保持手臂举过头顶不动是很重要的.
- During the resting part of the test, 您将收到更多的示踪剂，并将拍摄另一组照片. 这组图像将与运动或压力后拍摄的图像进行比较.
- 某些形式的测试不使用压力或运动，而是使用示踪剂拍摄一组静止图像.
The test takes between three and four hours. 一些实验室可能先做测试的休息部分，或者在不同的日子做休息和运动测试.
What happens after my MPI test?
- 您通常可以在您的健康护理专业人员的指导下恢复正常活动.
- 多喝水，把体内的放射性物质冲洗掉.
- 与你的医疗保健专业人员预约，讨论测试结果和下一步的步骤.
- 如果您计划在考试后几天内旅行，请索取您最近MPI考试的证明. 你体内的放射性物质可能会触发机场的警报.
