What is the appearance of a nodular interstitial pattern on X ray?
A normal chest radiograph typically shows many small nodular opacities that represent normal blood vessels end on. In most cases, these small nodules can be recognized as blood vessels because they overlap with a small line of similar diameter, which represents an adjacent branch of the pulmonary vascular tree. The nodular pattern of interstitial lung disease appears as increased numbers of small nodular opacities (<10 mm in diameter) that are randomly distributed throughout the lung parenchyma. These small nodules do not overlap with the normal vascular lines of the lung