THE GEOMETRY OF HUMAN CEREBRAL BIFURCATIONS - EFFECT OF STATIC DISTENDING PRESSURE

The geometry of five isolated, human cerebral bifurcations was studied over a range of transmural pressures. An atraumatic technique of apical transillumination was developed. This technique and semi-transparent nature of the cerebral arteries made it possible to photograph both external and internal features of bifurcation geometry at different transmural pressures over a wide pressure range and in multiple trials. The photographs were analyzed by computer digitization to obtain co-ordinate sets defining the outline of the internal apical curvatures. Curvature outlines were obtained at different transmural pressures over the pressure range 0-190 mm Hg for each bifurcation. Comparison of the curvatures showed significant differences in the size of the internal apical curvature with changes in transmural pressure. The size of the curvature increased with increasing transmural pressure and decreased with decreasing pressure.