The existence and detection of air in various tissues is of great importance, whether the air has emanated by a disease mechanism (for example, intra-abdominal in gastric lesions, extrapulmonary in thoracic lesions) or been applied as a diagnostic tool. The detection of the air in a diagnostic test may be performed by such different methods as stethoscopy (epidurally in the whoosh test1), or radiography (intra-articularly in arthrography2 ,3).

In ultrasonography the injection of ultrasound contrast agents containing air may increase the diagnostic confidence in the intravascular domain.4 ,5

Atmospheric air, which is much …