Fig. 4.20 PA CXR demonstrating multiple nodules and masses (within dotted ovals)

Fig. 4.21 CT demonstrating feeding and draining vessels, confirming AVM

Malignancy and congenital were highest on the differential due to multiplicity. CT was obtained (below) confirming multiple pulmonary arteriovenous malformations (AVM) in the lung.

Pulmonary AVMs are abnormal connections between the pulmonary arteries and veins. They are single in 65% of the cases, multiple in 35%. They are twice as common in women as in men, and the majority are congenital and are found in the lower lobes. Significantly, nearly 70% are associated with Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu disease), an autosomal dominant condition involving multiple AVMs in the brain, lung, skin, and liver.

Consolidation

Consolidation is defined as alveolar space that contains the fluid instead of air. In pneumonia, consolidation results when an infected lung passes from an aerated collapsible condition to one of airless solid consistency through the accumulation of exudates in the alveoli and adjoining ducts.

Fig. 4.24 Right lower lung field opacification. Note that the right heart border and right hemidiaphragm are obliterated, indicating RML and RLL consolidations

Consolidation may be caused by (differential):

•Hemorrhage – Blood

•Exudate – Pus

•Transudate – Water

•Secretions – Protein

•Malignancy – Cells

The mantra: “blood, pus, water, protein, cells” helps students and residents recall the consolidative differential and ensure it is understood and communicated. Also remember that conSOLIDation is more SOLID than ground glass opacities or airway pattern.

Consolidative Model

The following case/figures depict a model analogous to radiological findings of consolidation.

In the following PA and lateral CXR (Fig. 4.24 and 4.25), note the silhouette sign obscuring the right cardiac silhouette (right atrium) and right hemidiaphragm that help further localize the process. Also note the air bronchograms best seen on the lateral. There is a positive spine sign in that the spine does not get darker inferiorly as it should, indicating overlying density in the lower lobe consolidation.

Considering the case presented above, look at the common visual illusion below that can look either like two white faces (facing each other) or one central black vase.

This is presented to consider the air bronchogram, with the air as the exception in a predominantly dense consolidation. This is in contrast to the tram tracks that are two densities surrounding the bronchus in bronchiectasis, with the density as the exception to the predominant airway. These two concepts are often confused by

c

d

Fig. 4.25 Consolidative pattern, lateral view (a). Note positive spine sign, lucencies representing air-bronchograms and obliteration of right hemidiaphragm. The face-vase illusion (b) and tilted image (c) and squeezed (d) to simulate an air-bronchogram. See Fig. 4.26 for superimposed graphic on X-ray (Original image courtesy of S. Lehar. Manipulated versions of image created by USUHS ETI Support Office)

the beginning radiology student, hence are presented together to contrast these two very different entities.

Figure 4.26b depicts the popular faces and vase illusion and purposely narrowed to represent air as the exception as an analog to the air bronchogram within a consolidation, such as this case.

The following case again demonstrates air bronchograms with another analogy (see Fig. 4.2) [5].

The left lower lung field in this 53 year old contains a “complete air bronchogram,” meaning the tubular lucency extends from hilum to periphery. The right lower lung shows a less obvious air bronchogram exiting the hilum inferiorly.