Quantitative assessment of regional dysfunction from gated single photon emission tomography myocardial perfusion studies: A non-segmental approach

We present a modified (non-segmental) method for quantification of regional left ventricular dysfunction using gated myocardial perfusion SPET. Gated SPET is increasingly used to obtain complementary information on local perf usion and to assess the relevance of deficits in segmental count densities (attenuation vs perfusion deficit). The non-segmental approach was motivate d by a hypothetical limitation regarding the validity of commonly used meth ods of quantitative wall thickening (WT) analysis. These methods are all ba sed on segmental analysis, which could cause underestimation of 'true' cont ractile dysfunction in perfusion defects that do not have a strict segmenta l distribution. SPET images gated in eight time bins 60 min after the injec tion of 740 MBq Tc-99(m)-tetrofosmin or Tc-99(m)-sestamibi were recorded on a triple-headed camera in 20 normal subjects and in 16 patients within 2 w eeks and again 3 months after myocardial infarction. Normal limits of wall thickening, calculated from pooled wall thickening profiles obtained in nor mal subjects, were used to identify and quantify areas with abnormal wall t hickening in patients with coronary artery disease. The method was validate d against data obtained from contrast ventriculography (CVG) and tested for reproducibility. The reproducibility of the method was excellent: r = 0.98 (WTsev measure 1 = 1.03WT(sev measure 2) - 0.01). The localization of wall thickening abnormalities detected by gated SPET correlated well with the l ocalization of regions with abnormal wall motion (WM) identified by CVG. Th e severity of the regional myocardial dysfunction assessed by gated SPET wa s closely correlated with the severity of the regional myocardial dysfuncti on derived from CVG: r = 0.85 (WMsev = 2.55WT(sev) + 2.30). Furthermore, a good correlation between the total wall thickening severity score and the g lobal left ventricular ejection fraction (LVEF) was observed early and late after myocardial infarction: r = 0.80 (WTsev = - 0.4LVEF + 0.46). We concl ude that quantitative analysis of regional wall thickening assessed from ga ted SPET myocardial perfusion scintigraphy is a reliable parameter for regi onal ventricular function. Categorizing wall thickening abnormalities quant itatively may be helpful in assessing small changes in regional function th at may occur between sequential gated SPET images. ((C) 1999 Lippincott Wil liams & Wilkins).