[An anatomo-radiological study of changed tracheal transparency in the pathology of the superior mediastinum. Correlations and integration with mediastinal lines].

Twenty cases of mediastinal pathologies were examined with conventional radiology and Computerized Tomography (CT). They all (4 lesions in the superior and 16 in the postero-inferior mediastinum) presented with no significant changes in mediastinal borders. Conventional X-ray pictures were carefully examined for changes in mediastinal shape, and aerial tracheograms for "tracheal dimness"; CT scans were used as anatomical reference material. Mediastinal lines were detectable and evaluable in less cases than tracheal dimness was. The latter proved an useful sign for the evaluation not only of the pathologic condition itself, but also of the therapeutical reduction obtained in previously-diagnosed lesions. The routine study of tracheal dimness on conventional X-ray pictures appears to be an useful addition to the well-known signs of mediastinal pathologic conditions, especially when filters and high voltage are but seldom used.