SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Normally aerated lung
Watching the lung as the horse breathes; the visceral pleural edge of the lung is
imaged gliding ventrally across the diaphragm with inhalation and dorsally with
exhalation, "the gliding sign". In most normal horses there is no pleural fluid visualized.
However, small accumulations (up to 3.5 cm) of anechoic pleural fluid in the most
ventral portions of the thorax have been detected in clinically normal horses. The
diaphragm is curvilinear and appears thick and muscular in the more ventral locations
and thin and tendinous dorsally and caudally. The lung covers the cranial and caudal
mediastinum in most horses, although a hypoechoic soft tissue mass (thymus) may be
visualized in young horses in the cranial mediastinum ventral and medial to the right
apical lung lobe and cranial to the heart. Fatty tissue may also be imaged in this area
and around the heart, most commonly detected in ponies and fat horses. Fat is usually
slightly more heterogeneous and echogenic than thymus and continues caudally
around the heart into the caudal mediastinum.
Pleural Abnormalities
Pleural effusion
The most common pleural abnormality (pleural effusion) appears as an anechoic to
hypoechoic space between the lung, thoracic wall, diaphragm, and heart.
Pleural effusion with compression atelectasis
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