Fig. 8. A, A virtual reality image of two areas in the left lung with the ribs removed. The dorsal probe (blue arrow) is directly over a superficial area of consolidation that extends to the visceral pleural surface of the lung (depicted as a red discolored area under the probe). In contrast, the ventral probe is directly over a focal area of consolidation that does not extend to the visceral pleural surface. B, The lungs in the virtual reality image have been faced to reveal the areas of consolidation, depicting that the area of consolidation deep to the ventrally placed probe does not extend to the lung surface. C, The lungs in the virtual reality image have been removed to depict the sonogram that would be obtained in that plane. D, This is the sonogram from the dorsally placed probe showing the hypoechoic area of consolidation. Dorsal is to the left of the image. E, This is the sonogram obtained from the ventrally placed probe and shows no abnormalities. The presence of air in unaffected peripheral superficial lung precludes identification of deep areas of lung pathology, highlighting one of the major limitations of thoracic ultrasonography.
4. Discussion
Transthoracic ultrasonography is a fast and effective way to screen for superficial pulmonary dis- ease. Knowledge of normal thoracic anatomy and the general principles of ultrasonography are key ele- ments that assist in deciphering normal from abnor- mal ultrasonographic pulmonary architecture. The greatest limitation of thoracic ultrasonography is the fact that normal aerated lung precludes detection of deeper lesions. Thus, the absence of significant find- ings via transthoracic ultrasonography does not pre- clude the diagnosis of pulmonary disease, and additional diagnostics may be warranted.
Acknowledgments
Fig. 9. This image was obtained at the right eighth intercostal space. Dorsal is to the left of the image. The discrete hy- poechoic area was confirmed by biopsy to be fibrosis. This horse had EHV5-associated EMPF.
Declaration of Ethics The Author has adhered to the Principles of Veter- inary Medical Ethics of the AVMA.
