Orifice-view roentgenography of the mitral valve.

The mitral valve can be visualized as if looking directly into the valvular orifice by obtaining roentgenograms directed obliquely through the heart at a 25 degree superior elevation, with the patient rotated 60 degrees in the right anterior oblique direction. This view was based upon trigonometrical calculations of the spatial orientation of the annulus of prosthetic mitral valves in 25 patients. Calculations based upon measurement in these patients indicate that the area of the orifice of the mitral valve can be shown with less than ten percent error due to distortion of the projected image in 80 percent of patients. During the injection of contrast material into the left ventricle, orifice-view roentgenorgram serve as a useful adjunct to satndard ventriculograms. Such views permit assessment of the size of the mitral annulus and the degree of stenosis. Plain orifice-view roentgenograms of heavily calcified mitral valves permit measurement of the area circumscribed by calcium in such patients. The measurements indicate an upper limit of the possible size of the functional orifice. Therefore, this roentgenographic technique serves in a practical fashion as a non-invasive method for the assessment of the severity of mitral stenosis in such individuals.