Thallium-201 single-photon emission computed tomographic estimates of left ventricular mass in patients with and without ischemic heart disease.

A new automated edge detection program has been developed to estimate left ventricular mass from single-photon emission computed tomographic (SPECT) thallium-201 images of patients. Left ventricular (LV) mass was measured from contrast angiograms in 21 patients and was compared with LV mass estimated from thallium-201 tomographic studies. A comparison of angiographic mass to mass estimated from stress studies yielded an r = 0.97 (SEE = 21.6 gm) and a comparison of angiographic mass to mass determined from the redistribution images yielded r = 0.96 (SEE = 23.0 gm). Values of mass from stress and redistribution studies varied 7.3% +/- 6.7 and 8.8% +/- 9.2, respectively, when compared with values obtained by cineangiography. LV mass derived from the stress and redistribution studies were highly correlated (r = 0.97; SEE = 21.9 gm). Linear regression analysis revealed a slope of 1.06 (stress ventricular mass = 1.06 X redistribution mass - 14.9 gm). Thirteen patients had two thallium-201 SPECT studies performed approximately 1 month apart. Estimated LV mass was highly correlated when the two studies were compared (r = 0.94; SEE = 21.7 gm comparing the two stress studies; and r = 0.93, SEE = 19.4 gm for the two redistribution studies). We conclude that SPECT thallium-201 imaging can define LV mass accurately and reproducibly in normal, ischemic, or infarcted tissue.