ROENTGEN EVIDENCE OF NORMAL HEART AND CONGENITAL ABNORMALITY IN EARLY INFANCY

Factors that make it difficult to interpret cardiorespiratory difficulties in the newborn infant were studied by reviewing 1,000 chest roentgenograms obtained within 24 hours after birth. Two technical factors were found to prevent uniformity: It was difficult to eliminate rotation in a lively infant, and the technician could not always make the exposure at the height of inspiration. The large size and anterior location of the thymus added to the difficulty created by the high position of the diaphragm and other peculiarities of the normal infant's chest. Significant incomplete aeration of the lungs was noted in 181 cases, and in 127 of these the area of lung involved was chiefly the left upper lobe. The cardiothoracic ratio, which ranged from 44% to 74%, was generally rendered worthless as a diagnostic aid by the horizontal position of the heart, varying degrees of aeration of the lungs, and the almost inevitable presence of some degree of body rotation. Any concern about the heart raised by a chest roentgenogram obtained during the first 24 hours of an infant's life should not be shared with the parents until the presence of an abnormality is substantiated by other findings.