A Rational Method for Demonstrating the Heart

Abstract

It may seem preposterous to advocate a rational method for demonstrating the heart, since the image of this organ is one of the oldest and best-known roentgenograms. Still, when we consider the method usually employed we find two fundamental errors. In the lateral view, as you all know, the base of the heart is seen in the middle chest with the tip just touching the chest wall, the heart axis being at an angle to and not parallel to the anterior chest wall where the Film rests. In stout patients it is most difficult to approximate the upper chest snugly to the film. The same principle exists in radiating the upper teeth, where the apex is farther away from the film than the crown. But the oral roentgenologist has early overcome this distorted elongation of the root by projecting the tooth apex into the middle of the film and raising the focus, whereas many roentgenologists still adhere to the method which casts a distorted image of the heart. With this technic the central ray passes obliquely downward from the sixth dorsal rib in order to separate the heart from the dome of the diaphragm. This is possible in the average patient, but in all large and especially stout patients, weighing two hundred pounds and more, very little of the heart is seen on the roentgenogram because, with the degree of inspiration at which the exposure is taken, most of the heart shadow is hidden in the shadow of the diaphragm. However, if we lower the focal point to the tenth rib to overcome some of the distortion, still more of the heart shadow is hidden below the shadow of the diaphragm. But if we at the same time have the patient take an extremely deep breath, holding it a second with open mouth, and then make the exposure, we not only get a correct heart shadow but have it entirely separated from the shadow of the diaphragm. The central ray is above the dome and the lower divergent ray runs parallel with the front slope of the diaphragm, so that a sharp demarcation is obtained between the lower heart boundary and the shadow of the diaphragm. The lowered focus also gives a rounded, sharp outline to the tip of the heart and not the distorted one seen with the method which we formerly used. Before making the exposure the heart is studied fluoroscopically and the correct point for the central horizontal ray is noted, as is also the degree of inspiration which the patient is able to accomplish. It is anything but easy to induce a large, stout patient to take a sufficiently deep breath and to hold it long enough to insure an exposure. At first one sees only the upper part of the heart and is then surprised to see an enormous heart emerge out of the diaphragm shadow on deepest inspiration. The objection formerly raised against forced inspiration was, strange to say, the assertion that deepest inspiration narrows the heart image.