Which three chest projections are effective for visualizing air-fluid levels?

The erect posteroanterior (PA) chest projection is particularly effective for visualizing air-fluid levels within the thoracic cavity. In this position, the patient is upright, which allows for gravity to help separate fluids from air within the pleural space or other anatomical structures. This separation results in a clearer delineation of air-fluid levels, enhancing the diagnostic quality of the radiograph.

The upright position facilitates an accurate assessment of conditions such as pleural effusions or empyema, where fluid accumulates in one part of the thoracic cavity, as well as conditions affecting the lungs or heart. When identifying potentially problematic areas, such as fluid levels, having the proper orientation (being upright) significantly improves the radiologists’ ability to diagnose and treat patients effectively.

In contrast, other projections like the supine AP chest do not provide the same clarity for air-fluid levels due to the patient's position, which can cause fluid to layer evenly rather than pooling in a way that creates distinct levels. The lateral erect view may also assist in visualizing certain conditions but does not provide the same direct utility for assessing levels of fluid when compared to the erect PA view. The lordotic or axial recumbent projections have their own clinical uses, primarily assessing