Final answer:
The best two radiographic predictors of emphysema are hyperinflation and decreased vascular markings. These can be observed as a flat diaphragm and the loss of normal vascular network in chest X-rays, respectively.
Step-by-step explanation:
The best two radiographic predictors of emphysema are hyperinflation as evidenced by flat diaphragm on lateral chest X-ray and decreased vascular markings (or vascular pruning), particularly in the upper lobes. Hyperinflation can be identified by an increased anterior-posterior diameter of the chest and a lower, flattened diaphragm due to air trapping. Decreased vascular markings indicate the loss of the normal vascular network of the lungs due to the destruction of alveolar walls, which is characteristic of emphysema. While radiography can suggest the presence of emphysema, confirmation often requires pulmonary function tests such as spirometry, which measures the forced vital capacity (FVC) and the forced expiratory volume (FEV), particularly the FEV1/FVC ratio.