Spatial distribution and temporal changes of pulmonary thallium uptake in myocardial perfusion studies

Spatial distribution and temporal changes in pulmonary thallium uptake were assessed in 24 normal subjects and 35 patients with coronary artery disease (CAD). In studies carried out directly after stress and 3 h later, pulmonary Tl uptake was assessed as body surface area corrected absolute pulmonary uptake in the upper, middle and lower right lung regions, and in the total right lung and upper left lung. Pulmonary/myocardial (PM) uptake ratios for these 5 regions were calculated as mean pulmonary/mean background-corrected myocardial uptake. Additionally, wash-out was assessed for each region and for the myocardium. In normal subjects, the initial pulmonary Tl uptake, the PM ratios and Tl wash-out were greater in the lower lung regions than in the upper. In the late studies, no significant differences in Tl content or PM ratios were found among the regions. In patients with CAD, initial pulmonary Tl uptake and PM ratios were greater in the lower than in the upper regions, and higher than for the normal subjects in all pulmonary regions (P less than 0.001). Tl wash-out was significantly higher in the low and middle regions versus the upper region (P less than 0.001) and higher in all regions than in normal subjects (P less than 0.001). In the late studies no significant differences in Tl content or PM ratios were found between any pulmonary regions. Pulmonary Tl content was, in all regions, higher in CAD than in normal subjects (P less than 0.01), as were the PM ratios (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)