**3.3 Invasive research methods for aortic stenosis**

In order to measure the pressure gradient between the left ventricle and the aorta, probing of the heart cavities is performed. to which allows you to indirectly judge the degree of aortic stenosis. Ventriculography needed to detect concomitant mitral regurgitation. Aortography and coronary angiography are used for the differential diagnosis of aortic stenosis with an aneurysm of the ascending aorta and ischemic heart disease (**Figure 5**).

*Magnetic resonance imaging (MRI) of the heart is* a method of tomographic diagnostics, based on scanning the heart tissue with radio waves when the patient is in a powerful magnetic field. In the process of MRI, images of slices of the heart are obtained in different planes. High resolution characteristics of MRI make it possible to obtain detailed information about the structure of the cavities and valves of the heart, to conduct a study of the functional parameters of cardiac activity [8, 9, 13].
