Macroscopic basis of an early stage was a large cavity of destruction with insufficient spontaneous drainage, indistinctly separated from surrounding lung tissue and filled with purulent exudate with sequesters (25 patients). On bioplasm machine-graphy early stage was characterized by a neoplasm with heterogeneous structure due to diffuse distribution of lesser achromogenic areas of air beads against the background of prevailing isochromogenic content with heterogeneous suspensions and presence of large hypochromogenic< sequesters. Walls were not visualized, abscess was separated by lung tissue.

At the advanced stage we detected cavity of destruction with solid walls, properly drained by bronchi and containing mainly air, sequesters and small amount of purulent exudate (7 patients). On bioplasm machine-graphy it was characterized by heterogeneous neoplasm with prevailing long achromogenic objects with small amount of fluid in lower parts. Also homogeneous moderately chromogenic abscess wall of equal thickness with distinct external and indistinct internal walls was visualized.

Acute purulent processes are characterized by smaller than gangrenous abscesses size, often insufficient spontaneous drainage with heterogeneous diffuse distribution of achromogenic inclusions of air against isochromogenic background, absence of walls and sequesters. At adequate treatment we detected a positive dynamics in form of abscess cavity decreasing with simultaneous decreasing of fluid content amount and replacing by air. Further on a cicatrix was formed at the spot.