Modelling the integration of myocardial regional perfusion and function.

The purpose of the study is to describe a method for the investigation of myocardial kinetics (wall motion or wall thickening) to define myocardial perfusion characteristics further. The data are myocardial perfusion single photon emission computed tomographic images gated in eight time bins, following the administration of a 99Tcm-labelled perfusion agent. Wall motion is defined by the phase and amplitude of the centripetal motion of the first moment of the myocardial count rate density distribution along a radius originating in the centre of the left ventricular cavity. Wall thickening is defined by phase and amplitude of the changes in the second moment of the density distribution along the radius multiplied by the maximum density. Wall motion amplitude was abnormal in 28% of transient and 43% of fixed perfusion abnormalities, phase delays were present in 28 and 57%, respectively. Wall thickening was abnormal in amplitude in 14% of transient and 86% of fixed perfusion abnormalities. We conclude that the positive predictive value of wall-thickening abnormalities relative to fixed perfusion abnormalities is high (86%). Whether fixed perfusion defects with normal wall thickening represent viable myocardium remains to be investigated.