Chapter 4

Abnormal Lung Patterns

Abnormal Lung Parenchyma

As mentioned in the normal CXR section, the only structures visible in normal lungs are the fissures and pulmonary vessels. Any other structures visible are likely abnormalities. This section breaks down lung parenchymal abnormalities into five basic patterns that have been previously described, and taught in the National Capital Area residencies for years [1]:

1.Mass

2.Consolidative

3.Interstitial

4.Vascular

5.Airway

It should be kept in mind this is a findings-based approach and not the actual pathology that underlies the finding. For example, a mass finding is not always a “mass” in that abnormal vessels (e.g., AVM, rounded atelectasis or pneumonia, or aberrant vessels) may resemble a mass that represents vasculature or other process. Similarly, the vascular pattern may be primarily an abnormality of lung tissue surrounding the vessels causing compression or distortion, hence a secondary vascular effect. In other words, vessel distortion/alteration may be the only clue to the abnormality.

Mass

An opacity is classified as a mass when it is reasonably well defined and is not the shape of any anatomic structure of the lung, such as a complete lobe or segment. An opacity is also a mass when its borders are not entirely composed of fissures or the