Quantification of left ventricular size on exercise thallium-201 single-photon emission tomography

The purposes of this study were to determine whether quantification of the left ventricular size on exercise thallium-201 single-photon emission tomography (SPET) correlates with echocardiographic measurements, whether the quantification reflects the severity of coronary artery disease, and whether it can provide supplementary information regarding the severity of coronary artery disease. In 42 control subjects and 110 patients who underwent coronary angiography, we performed exercise 201Tl SPET and quantified six non-regional markers: lung 201Tl uptake on an initial planar image (Lung/Heart), left ventricular width on a tomogram (Width), change in the Width from the initial to delayed tomograms (DeltaWidth), count ratio of the left ventricular cavity to the myocardium (C/M), count ratio of the lung to the myocardium (L/M), and count ratio of the lung to the left ventricular cavity (L/C). In 76 patients, furthermore, the Width was compared with echocardiographic measurements. The Width correlated with echocardiographic measurements (P<0.001). The Width and DeltaWidth were significantly different among zero-, one-, two- and three-vessel disease (P<0.001). However, the Width and DeltaWidth could not improve the power of discrimination for multi-vessel disease derived from the Lung/Heart. The six non-regional markers correlated with each other (P<0.001). Among the six markers, the Lung/Heart was only the independent discriminator for multi-vessel disease. In conclusion, quantification of the left ventricular size on exercise 201Tl SPET correlated with echocardiographic measurements and reflected the severity of coronary artery disease, but may be replaced with quantitation of the lung 201Tl uptake.