Regional myocardial flow estimation using computed tomography.

Abstract

A novel method is presented for estimating regional myocardial blood flow (RMBF) using x-ray computed tomography (CT). Two major setbacks are removed from the existing methods; namely, the requirement for intra-arterial bolus injection of tracer, and the inability to determine regional volumes of tracer distribution when the corresponding partition coefficients are unknown. The mathematical model developed for RMBF estimation combines both the tracer dispersion process and the CT measurement process. Intravenously administered contrast media (tracer) is assumed to be perfectly mixed by the myocardium. Tracer dynamics, as measured by CT (CT#s. vs time curves) in the myocardial regions and in the left ventricular chamber, can then be used to compute cardiac output, regional volumes of tracer distribution, and absolute RMBF. These computations use the zeroth and the first moments of the measured CT#s. vs time curves. Errors due to partial volume effects, and methods for their correction, are analysed. This formulation is readily adapted to existing computed tomographic systems having the capability to produce multiple sequential CT scans.