The Melting Sign in Resolving Transient Pulmonary Infarction

A new concept of the resolution pattern of a pulmonary infarct as demonstrated on periodic follow-up chest roentgenographic examination is presented. For purposes of simplicity and identification, this concept has been termed the melting sign. The concept has been derived by the clinical roentgenologic observation over a number of years that many, if not most, pulmonary infarctions which go to resolution (and do not organize) present a roentgenologic pattern different from resolving pneumonia (Fig. 11; and 12). The importance of the observation may be stressed by the fact that, in some instances, the sign has been the initial finding leading to the establishment of the diagnosis of pulmonary infarction. Its greater value probably lies in establishing a higher confidence level in the diagnosis of pulmonary thrombo-embolic disease on plain chest roentgenograms when infarction coexists.