27.氣泡心臟超音波檢查（bubble echocardiogram）最主要是用來偵測何種臨床問題？
(A)偵測心肺的血液分流（shunt）
(B)偵測心包填塞（cardiac tamponade）
(C)偵測心臟瓣膜逆流（regurgitation）
(D)偵測主動脈瓣狹窄（aortic stenosis）

Echocardiogram with bubble study: A bubble echocardiogram is the same procedure as an echocardiogram, except an IV is placed in the patient's arm. During certain portions of the imaging, saline with bubbles is injected into the vein. This enables the cardiologist to see if there is a tiny hole between the upper chambers of the heart known as a PFO (patent foramen ovale) or ASD (atrial septal defect). This test is often done in conjunction with a transcranial Doppler or when the patient is experiencing neurological symptoms such as migraines, stroke-like symptoms, etc.

Cardiac Doppler: In this test, the ultrasound waves bounce off red blood cells moving within the heart chambers. This reveals the speed and direction of blood flow within your heart — and helps determine how well your heart valves are working.

Transesophageal echocardiogram (TEE): If you're having heart surgery — or if a standard echocardiogram produces poor images — your healthcare provider may order a transesophageal echocardiogram (TEE). With TEE, a provider will numb your throat and guide a transducer into your esophagus (through your mouth) until it rests directly behind your heart. From this position, the transducer can obtain high-quality images of your heart from all sides.

3D echo: Some echocardiograms are enhanced with 3D technology so that the doctor can rotate the image to see the heart from multiple angles.

Intracardiac echo (ICE) and intravascular ultrasound (IVUS): These ultrasounds use a catheter to give a view of the internal structures of your heart or coronary arteries. They may be done during cardiac catheterization.

Stress echo: A stress echo is a standard echo that is performed during or after a stress test to compare views of your heart at work and at rest.