Notebook: Radiology of Lung Disease 2

ALVEOLAR PULMONARY PATTERN, cont'd.
Atelectasis vs. pneumonia: You may have difficulty discerning the two on laterally projected rads, because both problems present in the ventral lung field. Take an orthogonal view; if you see a mediastinal shift on the VD or DV projection, this indicates atelectasis. If not, pneumonia may be indicated.

Remember: After looking at rads and coming up with differentials, ALWAYS check to see if your problem list matches the clinical signs! (for any rads, any case)

BRONCHIAL PULMONARY PATTERN
- indicates bronchial disease.
- results in thickened appearance of bronchi
- overall pulmonary pattern/ opacity is not that different
- typically all bronchi are affected.
- bronchiectasis: widened bronchi. A sign of chronicity.
- in older animals, bronchi are often mineralized.

Side note: right middle lung lobe is often collapsed in cats with asthma.

INTERSTITIAL PULMONARY PATTERN
- This pattern is usually diffuse.
- interstitial space: connective tissue that makes up the alveolar walls and the connective tissue around the big vessels and bronchi.
- interstitial pulmonary dz: on rads, everything is a little blurred.
- generalized increased opacity in the lungs. Still see all the structures, but they're not as sharp anymore.
- Since this is a hazy pattern by definition, it may be difficult to distinguish interstitial pulmonary pattern from poor radiograph quality. Check for good contrast between trachea, soft tissue and bone. Make sure that outlines of vertebrae are visible; check if you can see the dorsal spinous processes.

Metastatic nodule vs. end-on vessel: End-on vessel will always be brighter than a nodule, because it is a cylindrical structure. Also, it must sit on top of another vessel, which you sould be able to see as well.

Metastatic nodule vs. heterotopic bone: The smaller and the brighter the structure is, the less you have to worry. Heterotopic bone is very small and very bright.

If you are unsure if it's a nodule or not, ask the owner to come back in a week or so for more rads.

IF YOU CAN'T DECIDE ON A PATTERN
- i.e., if characterisitcs of multiple patterns are present
- just call the pattern a mixed pulmonary pattern
- these rads may not help reach a definitive diagnosis.

If lungs are too black: again, rule out artifact first (just as was discussed for whiteness in Radiology of Lung Disease 1).