Detection of subcarinal lymph node enlargement on conventional chest radiographs. With special reference to oblique views.

Sixty-nine consecutive cases were collected where subcarinal masses had been detected on conventional chest radiographs, including p.a., lateral and oblique views. The subcarinal masses represented metastases from lung carcinomas, from carcinomas in other organs or lymphomas. The radiologic findings were of 3 types: a) distortion of the mediastinal/lung interface; b) abnormal density of the subcarinal region; and c) deformation of the inferior wall of the left or right main bronchus, with or without simultaneous deformation of the tracheal carina. These changes occurred alone or in combination with each other. In the individual patient the subcarinal masses did not appear equally well on all radiographs obtained in different projections: on average they could be discerned in only 2 (1.86) projections out of the 4 obtained (p.a., lateral, LAO, RAO). There were no false-positive cases in the series.