Fleischner lecture. Biokinetic impacts on structure and imaging of the lung: the concept of biologically closed electric circuits.

The corona complex of the lung is a collection of radiographic features surrounding a pulmonary mass. Each of its 12 components may be explained by a recently described subset of biologically closed electric circuits, the vascular-interstitial closed electric circuit (VICC) system. This system is activated both by normal metabolism of tissue and by local degrading processes, such as spontaneous necrosis or hemorrhage, that lead to local electrochemical polarization of a lesion in relation to surrounding noninjured tissue. Ions, cells, and water are transported electrically in the VICC system, leading to the development of the corona complex. The VICC system is conceived to exist with the walls of arteries and veins functioning as insulators around the electrically conducting medium of blood, the plasma. Blood vessels therefore connect electrically the injured and noninjured tissues. At the capillary level, electric junctions connect plasma and interstitial fluid, which functions as an electrical conductor comparable to blood plasma. The interstitial fluid therefore completes the circuit. The VICC system can be regarded as an additional circulatory system for selective electrogenic transports, coupled directly to the mechanical circulation of blood and lymph. The injury potential represents an important energetic factor in the activation of the VICC system. It is a slowly fluctuating, attenuating, electrochemical potential inducing ebb and flow of time-dependent anionic and cationic transports. The corona structures are special effects of the healing of injured tissue. The 12 radiologic signs of the corona complex have each been produced experimentally in vitro in animals and in vivo in humans during electrochemical treatment of cancers. The "A" zone is characterized radiographically by radiolucency around an electrically polarizing focal lesion. Peripheral to the A zone, a "B" zone is seen as a radiopaque region. The A and B zones are predominantly the result of an electroosmotic outflow of water from a lesion during its electropositive phase. At the interface between the A and B zones, small arches sometimes form an arcade. This configuration develops when the polarizing lesion has small protrusions at its surface. As a result of electrical edge enhancement, various elements of the interstitial tissue are transformed into radiating fibrous structures. They grow out at right angles to the surface of the lesion and serve as supporting columns for the arches. When necrotic material from a tumor is evacuated through a bronchus, ensuing collapse of the tumor will displace those radiating structures already produced.(ABSTRACT TRUNCATED AT 400 WORDS)