Which procedure provides a definitive diagnosis for angina?

The definitive diagnosis for angina, particularly in cases where there is suspicion of coronary artery disease, is provided by a coronary angiogram. This procedure allows for direct visualization of the coronary arteries, identifying blockages or narrowing that could lead to angina symptoms. During a coronary angiogram, a contrast dye is injected into the coronary arteries, and X-ray images are taken to assess blood flow and detect any abnormalities.

In contrast, other imaging techniques like cardiac MRI, CT scans, and echocardiograms provide valuable information but do not definitively visualize the coronary arteries in a manner that would allow for the direct assessment of angina's underlying causes. A cardiac MRI offers detailed images of the heart's structure and function, a CT scan can provide information about coronary artery calcium and possible blockages, and an echocardiogram evaluates cardiac function and structure through ultrasound. However, none of these procedures can definitively diagnose the presence and severity of coronary artery disease as effectively as a coronary angiogram can.