Definitions for "Alveolar densities"
An abnormal density caused by the collapse or, more often, the filling of air spaces with abnormal material (blood, pus, water, protein, or cells). Alveolar densities characteristically have irregular, hazy margins except where they are bounded by a pleural surface. (Also referred to as "acinar pattern".) Segmental distribution and air bronchograms are also characteristic of this pattern.