Therefore, the normal lung parenchyma should not appear completely black on a good quality radiograph but consist of a black background with gray branching, smoothly delineated vessels being visible throughout the lung field (Figure 1). (https://bre.is/eWggXH6v)

The central pulmonary arteries are enlarged and there is an increase in both size and number of well-defined sharply delineated vessels in the perihilar region bilaterally consistent with “shunt vascularity” (Fig.1). (https://bre.is/H9v5LJWS)

This image provided good anatomical landmarks of the well-delineated pulmonary vessels (https://bre.is/EubZyrUe)