A(n) __ uses ultrasound to visualize internal cardiac structures. Doppler ultrasound stress test echocardiogram angiogram

## Step 1<br />The problem is asking us to identify the medical procedure that uses ultrasound to visualize internal cardiac structures. The options provided are Doppler ultrasound, stress test, echocardiogram, and angiogram.<br /><br />## Step 2<br />Let's analyze each option:<br /><br />### Doppler ultrasound<br />This is a special type of ultrasound that measures the flow of blood through the heart. It is used to detect any abnormalities in the blood flow, but it does not provide a visual image of the heart's internal structures.<br /><br />### Stress test<br />This is a test that measures the heart's ability to respond to external stress in a controlled clinical setting. It does not involve the use of ultrasound to visualize the heart's internal structures.<br /><br />### Echocardiogram<br />This is a test that uses sound waves to produce live images of the heart. It can show how well the heart is working and can detect any abnormalities in the heart's structure.<br /><br />### Angiogram<br />This is a test that uses X-rays to take pictures of your blood vessels. It does not involve the use of ultrasound to visualize the heart's internal structures.<br /><br />## Step 3<br />Based on the above analysis, the correct answer is echocardiogram, as it is the only option that uses ultrasound to visualize internal cardiac structures.