Assessment of Ventricular Function and Phase Abnormality by Gated Blood Pool Scan in Dilated Cardiomyopathy

ABSTRACT

Gated blood pool scan(GBPS) may be used for evaluating patients with dilated cardiomyopathy(DCM) where it can assist in the diagnosis, and evaluation of severity, disease progression or therapeutic efficacy. In addition to the routine parameters that have been available by GBPS, relatively simple mathematical manipulations of the equilibrium time activity curve can derive parameters relating to the degree and sequence of ventricular emptying. This first harmonic phase analysis may enable quantitative and more specific measurements of wall motion abnormalities in DCM and may thus be useful for more accurate assessments in these patients. Thus, in an attempt to evaluate the findings of phase analysis in DCM and to determine their possible usefulness in this entity, we measured parameters of phase analysis from the resting GBPS of 25 DCM patients and 11 normal controls, and compared these with other parameters of ventricular function from GBPS or echocardiography. Parameters of the systolic as well as diastolic function were markedly depressed for both left and right ventricles (all p<0.001), and echocardiographic LV systolic diameter was increased in all patients. Phase analsis showed the mean and standard deviation of phase angle(Mph & SDph) of both ventricles to be singificantly greater, and the mean amplitude smaller in DCM patients compared to controls(p<0.01). SDph appeared to be a sensitive parameter(LV 100%, RV 92%), and LV SDph showed significant correlations with other GBPS parmeters such as LV ejection fraction(LVEF) and LV peak ejection rate(LVPER) (r=-0.85 and 0.75, respectively) (all p<0.001), and with LV systolic diameter (r=0.78, p<0.001). Also, LV mean amplitude correlated well with LVEF (r=0.79, p<0.001). Thus, phase analysis of GBPS was able to show and quantify significant asynchronity in contraction of both ventricles in DCM, and these parameters may by useful in evaluating ventricular performance in these patients.