Effect of stress on the myocardial kinetics of T-butylisonitrile-technetium (Tc-99m-TBI)

Abstract

T-butylisonitrile-technetium-99 m (TBI), a technetium labeled myocardium imaging agent was investigated in ten male patients with coronary heart disease. Kinetics of TBI were evaluated by means of transfer function analysis of organ time-activity curves. First-pass uptake values at rest showed the following decreasing order: liver, spleen, normal myocardium, lung and ischemic myocardium. Mean turnover times were shortest in the lung and of increasing order longer in spleen, normal myocardium, ischemic myocardium and liver. Under stress first pass uptake increased in myocardium and decreased in liver and spleen, while turnover times became prolonged. Thus kinetics of TBI are characterized by definite turnover rates and not by trapping in various tissues, which has to be considered during evaluation of scintigraphic images.