Assessment of calcific aortic stenosis by measurement of area circumscribed by calcium on plain film orifice-view roentgenograms.

A direct measurement of the severity of stenosis of heavily calcified aortic valves was accomplished by a noninvasive roentgenographic technique. This was accomplished in 12 patients, using plain roentgenograms obtained at a projection specifically derived for this purpose. The x-ray beam was directed obliquely through the heart at a 45° superior elevation in the frontal plane. At this angle, the aortic valve can be visualized as if looking directly into the orifice. In patients in whom there was a fully circumferential ring of calcium, the area circumscribed by calcium served as a reliable indicator of the upper limit of the size of the orifice, which was not exceeded in any of the patients. This was of practical clinical value in patients in whom the perimeter of calcium circumscribed a markedly narrowed area. The very presence of a complete circumferential ring of calcium, as delineated on these roentgenograms, indicated a maximum functional orifice area of 0.5 cm 2 . A linear relation between dimensions of the deposits of calcium and the actual dimensions of the orifice permitted an estimation of the actual length of the axes of the valves from the regression equation.