BRONCHOARTERIAL INVERSION - RADIOGRAPHIC-CT CORRELATION IN COMBINED RIGHT MIDDLE AND LOWER LOBE COLLAPSE

Pulmonary arteries of the right middle (RML) and right lower (RLL) lob es lie toward the lung periphery relative to their corresponding bronc hi, i.e., along their lateral or posterior aspects. In contrast, those of the right upper lobe (RUL) tend to be located along the medial or anterior aspect of the bronchi. We postulate that a reversal of the no rmal bronchoarterial relationship at the lung base may indicate combin ed RML and RLL collapse. We evaluated bronchoarterial relation by comp uted tomography (CT) and posteroanterior (PA) chest radiographs in pat ients with combined RML and RLL collapse. On PA chest radiographs, an inverse bronchoarterial relationship could be recognized in the lower perihilar region in seven of 10 patients. In the 10 patients with comp lete collapse of both the RML and RLL, CT disclosed that the normal br onchoarterial relationship of the RUL was preserved, despite caudal ex tension of the RUL. In no case were arteries visible along the lateral aspect of bronchi. Thus, on frontal radiographs, when the bronchoarte rial relationship in the right lower lung is inverse to that of normal subjects, combined collapse is strongly suggested.