An abscess with air cavity was registered after cleaning out of purulent exudate from remained cavity of destruction with formed solid capsule. In the spot where it touches a thoracic wall we detected arcual strip with uneven, jugged surface. To evaluate such air cavities roentgen examination is preferable, because it allows to visualize the whole cavity, not only a mural spot.

In case of cleaned cavity collapse and at its cicatrization, at the place of an abscess was formed a fibrous area of irregular shape with uneven and indistinct contours and isochromogenic structure because of separate hyperchromogenic inclusions against the background of moderately chromogenic fibrous tissue. Maximum size of such area was less than 2 cm. At significant adhesive changes at the level of an abscess locally thickened hyperchromogenic pleura (4-5 points at Fleindler’s scale) of up to 6 mm was visualized.

We have carried out comparative analysis of 62 acute purulent and 32 gangrenous abscesses and defined criteria for their differential diagnostics, which were: efficiency of spontaneous drainage, presence of hyperchromogenic wall and necrotized sequesters of lung tissue. All patients suffering from gangrenous abscesses were subjected to surgical treatment (thoracoabscessotomy), that allowed to evaluate visually macroscopic structure of purulent cavity. Comparison with acquired bioplasm 9d nls-picture we singled out early and advanced stages of gangrenous abscess, associated with various efficiency of spontaneous drainage and presence of a wall.