Curriculum · Respiratory
Chest radiograph interpretation: consolidation versus lobar collapse
What it is
Consolidation is airspace disease, which is the same thing as alveolar infiltrates. Two features are recorded for it: it is dense, and it carries an air bronchogram. Collapse is the other reading a dense area may carry, and the two are told apart on the same film, in the same lobe.
How it is diagnosed
A reading names the lobe and then names the process, and the lobes are the right upper, the left upper, the right middle, the right lower and the left lower. So the answers a single film has to choose between run: right upper lobe collapse, right middle lobe consolidation, right middle lobe collapse, right upper lobe consolidation. Naming only the process, or only the lobe, is half a reading. An air bronchogram belongs to the consolidation side of that choice. Two signs do the work on the film. An air bronchogram means consolidation. The other is the loss of a border, and the border that is lost names the lobe: loss of the diaphragm border puts the disease in a lower lobe, and it is also the sign of an effusion; loss of the right heart border puts it in the right middle lobe; and loss of the left heart border puts it in the lingula. So a film that has lost the right heart border puts the disease in the right middle lobe, not in a lower lobe and not in the lingula. Collapse is read from volume loss instead: the trachea pulled to the right or left, the fissures pulled, the hilum pulled up or down, a raised diaphragm and crowded ribs. And a meniscus is a pleural effusion.