Usefulness of left ventricular wall thickness‐to‐diameter ratio in thallium‐201 scintigraphy

The ratio of left ventricular wall thickness to the cavity dimension, as seen on thallium-201 images, was used in this study to predict left ventricular ejection fraction and volume. We obtained rest thallium-201 images in 50 patients with symptomatic coronary artery disease. The thickness of a normal-appearing segment of the left ventricular wall and the transverse diameter of the cavity were measured in the left anterior oblique projection. The left ventricular ejection fraction and volume in these patients were determined by radionuclide ventriculography. There was a good correlation between thickness-to-diameter ratio and ejection fraction (r = 0.80) and end-systolic volume (r = -0.71). In 18 patients with a thickness-to-diameter ratio less than 0.70, the ejection fraction was lower than in the 16 patients with thickness-to-diameter ratio greater than or equal to 1.0 (22 +/- 2% versus 49 +/- 3%, mean +/- SEM, p less than 0.001). Similarly, in patients with a thickness-to-diameter ratio less than 0.70, the end-diastolic and end-systolic volume were higher than in the remaining patients with higher thickness-to-diameter ratios (p less than 0.02, p less than 0.001, respectively). All 18 patients with a thickness-to-diameter ratio less than 0.70 had ejection fractions less than 40%; 14 of 15 patients with a thickness-to-diameter ratio greater than or equal to 1.0 had an ejection fraction greater than 40% (p less than 0.001). The remaining 16 patients with a thickness-to-diameter ratio of 0.7-0.99 had intermediate ejection fractions and volumes.(ABSTRACT TRUNCATED AT 250 WORDS)