There is paucity of vascular markings in outer third of lung fields

There is paucity of vascular markings in outer third of lung fields
In left to right shunts (ASD, VSD, PDA) and in high output states, there is increased pulmonary flow, the vascular markings in the outer third will be prominent.
In interstitial disease, lymphangitic malignant spread and in CHF with increased lymphatic flow the markings in outer third will be prominent.