ESTIMATION OF RIGHT VENTRICULAR PRESSURE BY TL-201 SCINTIGRAPHY IN PEDIATRIC CARDIAC DISEASE

To estimate right ventricular overload in paediatric cardiac disease,201T1 scintigraphy was used to quantify right ventricular uptake. Six methods for calculating the201T1 right-to-left ventricular uptake ratio (TRL) were compared, based on the location of regions of interest (ROIs), use of total count or mean count density, and the ROI-based method or profile method. When the TRL was compared with the right-to-left ventricular peak systolic pressure ratio (RVP/LVP), the mean count density method using entire right and left ventricular ROIs seemed to be appropriate, considering its simplicity, reproducibility and regression line. The linear regression line was RVP/LVP=1.15×TRL—0.13 (n=15, P=—0.0001), and RVP(mm Hg)=162×TRL—33 (n = 15, P=0.0001). In four patients with pulmonary stenosis, the changes of TRL were in good agreement with the right ventricular pressure changes after percutaneous balloon valvuloplasty. Thus, evaluation of thallium scintigraphy using this quantitative method can be a simple and effective way to evaluate patients with right ventricular pressure overloading. © 1990 Chapman and Hall Ltd.