Background: We have assessed the reproducibility of the estimates of regional left ventricular wall thickening between resting and redistribution Tl gated single photon emission computed tomography (SPECT) studies.
Methods: Thirty patients (28 males, two females) aged between 38 and 72 years (57.0 +/- 8.4 years) underwent resting and redistribution Tl gated SPECT. Perfusion was assessed semi-quantitatively using scores of 0-4. The assessment of wall thickening was performed both visually and by using automated software using scores of 0-3. The assessment of reproducibility was performed in 20 individual segments and 37 pairs of contiguous segments in each patient.
Results: In resting studies, mean global left ventricular ejection fraction (LVEF), end diastolic volume and end systolic volume were 34.2 +/- 11.7%, 180.5 +/- 70.6 ml and 123.3 +/- 60.0 ml, respectively. The corresponding values for the redistribution studies were 32.7 +/- 10.1%, 179.7 +/- 70.6 ml and 125.5 + 63.0 ml, respectively. There was good correlation between the resting and redistribution LVEFs (r=0.88), end diastolic volumes (r=0.90) and end systolic volumes (r=0.933). Reproducibility of visual wall thickening was 66% in individual segments and 82% in pairs of contiguous segments, and that of automated wall thickening was 48.0% in individual segments and 68% in pairs of contiguous segments.
Conclusion: In conclusion, global left ventricular functional parameters obtained by resting Tl gated SPECT studies are highly reproducible in patients with impaired resting left ventricular function and large areas of scarred myocardium. Wall thickening and wall motion data are more reproducible in contiguous segments than in individual segments.