Assessment of regional myocardial wall motion and thickening by gated Tc-99(m)-tetrofosmin SPECT: a comparison with magnetic resonance imaging

Gated single photon emission computed tomography (SPECT) imaging allows the simultaneous assessment of both perfusion and function by using one single study. The assessment of regional wall motion and thickening pattern with gated SPECT allows viability studies to be performed. Magnetic resonance im aging (MRI) is well validated for the assessment of myocardial wall motion and thickening in patients with normal and impaired ventricular function. T he aim of the study was to analyse the concordance between wall motion and thickening scores derived by gated SPECT and MRI imaging. Furthermore, the agreement for myocardial wall motion and thickening according to myocardial perfusion was analysed with both techniques. We studied a group of 21 pati ents, including 13 with a previous myocardial infarction (all more than 4 m onths before the study), using both gated SPECT Tc-99(m)- tetrofosmin myoca rdial perfusion imaging and MRI. A 13-segment model was used for both gated SPECT and MRI and each segment was visually scored using a scale of 1-3 fo r wall motion and thickening. There was a high agreement between gated SPEC T and MRI for both wall motion (229/273, 84%; k = 0.72, P < 0.001) and wall thickening (236/273, 86%; k = 0.77, P < 0.001). The agreement for wall mot ion and thickening was 80% (k = 0.66) and 83% (k = 0.70), respectively, for patients with myocardial infarction; and 90% (k = 0.81) and 92% (k = 0.86) , respectively (P = NS), for patients without myocardial infarction. Agreem ent in segmental wall motion and thickening scores between gated SPECT and MRI was 90% (k = 0.80) and 91% (k = 0.84), respectively, for segments with normal or mild to moderate hypoperfusion; and 71% (k = 0.45) and 77% (k = 0 .57), respectively, for segments with severe hypoperfusion or no perfusion. Of the 70 (41%) segments that had severely diminished or no perfusion in p ost-myocardial infarction patients, 22 (31%) showed preserved wall motion a nd 17 (24%) showed preserved wall thickening both by gated SPECT and MRI, s uggesting residual myocardial viability in malperfused segments. Our result s suggest that gated SPECT imaging is a reliable tool for the assessment of regional wall motion and thickening in patients with known or suspected co ronary artery disease. In patients with a previous myocardial infarction ga ted SPECT imaging has the potential to detect preserved wall motion and thi ckening in regions with fixed perfusion defects indicating the potential pr esence of residual myocardial viability. ((C) 2001 Lippincott Williams & Wi lkins).