Assessment of Cardiac Blood Pools in Radiocardiography by Various Indicator Dilution Models

Abstract

SummaryHeart blood pools were evaluated by different indicator dilution models from single detector 113mIn radiocardiographic measurements on healthy subjects. It appeared that generally accepted mathematical expressions based on the nth moments of the radiocardiographic dilution curve overestimate the heart volumes by 30–40%. The study suggests that the indicator dispersion within the heart chambers is an dilution process, which ought to be included in the radiocardiographic models. Dispersion models based on the random walk equation, probability density function and the gamma variate model produced consistent heart volumes. The suitability of the dispersion models for clinical routine use is discussed briefly.

Gamma Variate Analysis of Pulmonary Dilution Curves for Quantitation of Left-to-Right Cardiac Shunts

“…It is obvious that the mean transit time ( M I T ) of the shunt curve exceeds the MTT of the pulmonary flow curve due to the indicator dispersion in the recirculation pathway (6). However, the difference in the MTTs is O l k k o n e n G a m m a Variate Analysis of P u l m o n a r y Dilution Curves for Q u a n t i t a t i o n of L e f t -t o -R i g h t Cardiac Shunts about the same as that measured between the right and left heart sides, which equals 10% (7,8). The result is only a slightly smaller area of the shunt curve, but it is not of significance in practical clinical studies.…”