ICU Chest Films > Fluid in the Chest > Pleural Effusions > Radiographic Appearance

Radiographic Appearance of Pleural Effusions

The appearance of a pleural effusion on a chest film is largely dependent on the position of the patient. Fluid in the chest cavity will accumulate in the dependent areas of the chest. This makes idenitifing small collections extremely difficult, especially in the supine patient. Fluid in the posterior basilar space appears as an homogenous graded increase in the density of the lung base, maximal inferiorly. The normal bronchovascular markings are not lost. As the amount of fluid increases, the diaphragmatic contour and lateral costophrenic sulcus may be obliterated.

Bilateral pleural effusions in a supine patient. This film demonstrates fluid in the posterior basilar space without loss of normal bronchial markings.

What are the most dependent spaces in the supine patient? (More than one)
Posterior basilar space
Costophrenic sulcus
Apex
Perihilar space