**Core Concept**
Reversible myocardial ischemia occurs when there is a temporary reduction in blood flow to the heart muscle, leading to a decrease in contractility and potentially resulting in chest pain or other symptoms. This condition is often detected using a specific non-invasive test.

**Why the Correct Answer is Right**
The test used to detect reversible myocardial ischemia is the **Stress Echocardiogram**. It involves a combination of physical exercise or pharmacological stress to increase heart rate and blood pressure, followed by echocardiography to assess regional wall motion abnormalities in the heart muscle. This helps identify areas of ischemia that return to normal after rest. The stress echocardiogram is particularly useful in patients with known or suspected coronary artery disease.

**Why Each Wrong Option is Incorrect**
**Option A:** **Thallium-201 Scan** is a nuclear medicine test used to evaluate myocardial perfusion, but it is not the primary test for reversible ischemia.

**Option B:** **Multidetector Computed Tomography (MDCT)** is a high-resolution imaging test that can visualize coronary artery calcification and plaque, but it is not typically used to detect reversible ischemia.

**Option C:** **Holter Monitoring** is a 24-hour electrocardiogram (ECG) used to detect arrhythmias and other cardiac rhythm abnormalities, but it is not relevant to detecting reversible myocardial ischemia.

**Clinical Pearl / High-Yield Fact**
The stress echocardiogram is a useful test for detecting reversible myocardial ischemia, especially in patients with known or suspected coronary artery disease. It is often performed in conjunction with a physical exercise stress test or pharmacological stress.

**Correct Answer:** C.