Which test does not allow for the calculation of the cardiac ejection fraction?

The cardiac ejection fraction (EF) is a measurement that indicates how well the heart is pumping blood, calculated as the percentage of blood that is pumped out of the heart's ventricles with each beat. An echocardiogram, cardiac MRI, and stress test all provide information about cardiac function that can be used to calculate the ejection fraction.

A chest X-ray, however, primarily provides images of the heart and lungs but does not offer functional measurements like ejection fraction. While it can help identify conditions such as cardiomegaly (enlarged heart) or fluid overload, it lacks the ability to assess the heart's pumping efficiency directly. Therefore, a chest X-ray cannot be used to calculate the cardiac ejection fraction, making it the correct choice in this context.