[Quantitative evaluation of right ventricular overload in cor pulmonale using 201T1 myocardial SPECT]

In patients with right ventricular overload, the free wall of the right ventricle is often visualized by 201T1 myocardial scintigraphy. To determine quantitatively the discriminant and characteristics of cor pulmonale, 201T1 myocardial perfusion single photon emission computed tomography (SPECT) was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and seven with restrictive pulmonary disease (RPD). We selected one section of the short-axis image of SPECT in which the right ventricle was most clearly visualized, and defined the T1-score as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid and posterior regions of the right ventricular free wall to the sum of counts in the ROI at the posterior, lateral, anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. Correlation of the T1-score with mean pulmonary arterial pressure (mPAP), systolic pulmonary arterial pressure (sPAP), and total pulmonary vascular resistance (TPR), as obtained by right cardiac catheterization, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) were evaluated. The results were as follows: 1. In the patients with COPD, the T1-score correlated positively with mPAP (r = 0.71, p less than 0.005), TPR ( r = 0.69, p less than 0.005), and PaCO2 (r = 0.63, p less than 0.01), and it correlated inversely with PaO2 (r = -0.58, p less than 0.05). However, there was no significant correlation between the T1-score and mPAP, TPR, PaCO2, and PaO2 in the patients with RPD.(ABSTRACT TRUNCATED AT 250 WORDS)