[Right ventricular volume determination by continuous 81mKr infusion and 99mTc blood pool imaging]

Our newly developed radionuclide method for the calculation of right ventricular (RV) volume was examined in this study. Using a semi-geometric count-based method, volume can be measured by the following equation: Cv = Cm/(L/d). V = (Ct/Cv) x d3 = (Ct/Cm) x L x d2. (V = volume, Cv = voxel count, Cm = the maximum count of a container, Ct = the total count of the container, L = maximum length of the image of the container obtained from a direction perpendicular to the direction where the count data were collected, and d = pixel size.) A phantom study was performed by setting a cylindrical container in a system which circulated 5 liters of water per minute. 81mKr solution was infused continuously into the container, and images of the container were collected for one minute. Cm and Ct were obtained and, because the container was cylindrical, the maximum width of the image of the container was measured as L. The volume of the container was calculated using the above equation. The container's true volume and the volume measured by this method showed a good correlation with r = 0.997 (n = 13, p < 0.001). This theorem was applied to RV images obtained in the 30 degree right anterior oblique position by continuous infusion of the 81mKr solution. Multiple gated acquisition was performed and RV end-diastolic maximum counts and total counts were obtained. The RV maximum width was measured as L on the end-diastolic cardiac pool image with 99mTc-D-HSA collected in the 40 degree left anterior oblique position.(ABSTRACT TRUNCATED AT 250 WORDS)