A decade or more of cranial and caudal angled projections in coronary arteriography—another look

Abstract

The introduction of selective coronary angiography by Mason Sones [l] was a milestone in the diagnosis and treatment of heart disease. This has been paralleled in the advances in X-ray techniques dedicated to the examination of the heart and coronary circulation. The current metal-input cesium iodide image intensifiers capable of resolving over seven line pairs/mm are a far cry from the old zinc cadmium sulfide intensifiers, which resolved less than 1.5 line pairdmm. Similarly, the development of high-resolution television systems, the improvement in X-ray tubes, and the advent of computerized generators have made a major contribution to superior imaging of the heart. Not infrequently, patients restudied on the new X-ray systems are found to be surgical candidates, having been previously turned down because of apparent disease in the distal vessels in films obtained with earlier generation image intensifiers.The mounting of image intensifiers and X-ray tubes has also been substantially changed. In the sixties, the projections were usually limited to the transverse oblique plane. Often the patient had to be propped up uncomfortably on pillows or wedges. The introduction of the rotating cradle in the mid-sixties certainly made the procedure more comfortable for the patient but did not significantly improve the diagnosis. The importance of these angled views gave rise to a totally new generation of X-ray equipment for cardiac use. Modified C-or U-arms were developed, which allowed the equipment to be rotated around the patient with the heart placed in the isocentric point of the X-ray system. Now, not only cranial but also caudal angles were easily obtainable. This mechanical sophistication, however, was also associated with an increased cost for X-ray equipment. Some institutions found that financial constraints did not permit the scrapping of their existing X-ray systems. Thus a number of simple structural mechanisms were devised [7] to obtain at least cranial angles, such as those published in this issue. There is, however, no doubt that caudal angles are as important as cranial angles [lo-131. An analysis of the early experience with special angled projections showed that a substantial improvement in diagnosis could be obtained in 54 % of patients studied [9]. More recent reports based on large numbers of patients suggest that in certain instances improved visualization can occur in up to 93% of studies [12,14,15]. Thus, by today's standards, the nonuse of such special Address reprint requests to

Questions and Answers

“…1,2 In analyzing the issue, courts have noted various factors relevant to the insurance requirement. They include (a) the importance of physicians being able to compensate patients for injuries for which they are legally responsi¬ ble, (b) the potential increase in the hospital's costs if medical staff members are not covered, (c) the possible adverse effects on patient care if physicians without insurance refuse to treat certain patients, and (d) the inability of some physicians without insurance to partici¬ pate with others who have been found negligent if an adverse decision is rendered.…”