Comparison of SPECT and Gated SPECT for detection of multivessel coronary artery disease

Full text: The aim of the study is the comparison of the sensitivity and the specificity of SPECT and Gated-SPECT for multivessel coronary artery disease (MVD) and determination of the most appropriate approach for accurate MVD diagnostic. Thirty three patients are examined by Gated SPECT Tc99m sestamibi stress and rest myocardial perfusion scintigraphy in order to determine the extent of the perfusion abnormalities and to take decision for therapy. The reference method is coronary angiography. The changes in left ventricular ejection fraction (ΔLVEF) and in left ventricular cavity (s.c. transit left dilation - TLD) with exercise are tested for detection of MV involvement. ΔLVEF is determined from QGS analysis. Regular R-R intervals during registration is the condition for exact determination of ΔLVEF. TLD and the perfusion abnormalities could be obtained from non-gated, or summed gated images. We have estimated as significant ΔLVEF >3% and TLD > 1.2. The sensitivity of the decrease of LVEF with exercise for MVD is 84%; the specificity ? 60%. TLD has same sensitivity - 80% and better specificity- 85%. The visual evaluation of multiple perfusion abnormalities has 100% sensitivity and 90% specificity, but with the help of Gated SPECT images for detection of mild abnormalities, including in kinetic, or perfusion artefacts. The low specificity of the decrease of LVEF is always related to proximal left anterior descendent disease with extensive perfusion abnormalities. Conclusion: The visual evaluation of the perfusion abnormalities is highly accurate for determination of MVD. The enlargement of LV cavity and the decrease of LVEF with exercise, related to extensive abnormalities are however important for MVD detection. Advantage of TLD is that it can be obtained from conventional SPECT, but the advantages of Gated SPECT are the detection of mild perfusion abnormalities and perfusion artefacts