Abstract 1648: Agreement and Disagreement between Contrast-Enhanced Magnetic Resonance Imaging and Nuclear Imaging for Assessment of Myocardial Viability
Purpose To determine the agreement between contrast-enhanced MRI (ce-MRI) and nuclear imaging for assessment of viability in patients with severe ischemic LV dysfunction.
Methods Patients (n = 25) with severe ischemic LV dysfunction (EF 25 ± 11%) were studied with cine MRI, ce-MRI, 99m Tc-tetrofosmin single photon emission computed tomography (SPECT) and 18F-FDG SPECT. Using a 17-segment model, each segment was assigned a wall motion score (0: normokinesia to 4: dyskinesia) and a scar score (0: no infarction to 4: 76–100% transmurality). Furthermore, 99m Tc-tetrofosmin and 18F-FDG segmental tracer uptake was categorized (0: tracer activity > 75% to 3: tracer activity < 25%). Dysfunctional segments were classified into viability patterns assessed with SPECT: normal pattern (normal perfusion and metabolism), mismatch (decreased perfusion, increased metabolism), mild match (mild decrease in perfusion and metabolism), and severe match (severe decrease in perfusion and metabolism). Difference in scar score between viability patterns was assessed using one-way ANOVA analysis.
Results Of all analyzed segments (n = 425), 289 (68%) showed abnormal wall motion. Mean scar score was 0.3±0.7 in segments with a normal viability pattern, 1.0±1.2 in mismatch, 1.3±1.0 in mild match and 2.7±1.0 in severe match (p<0.001 between all patterns, NS between mismatch and mild match). The relation between MRI and SPECT is presented in Figure 1⇓.
Conclusion Agreement between MRI and nuclear imaging for assessment of viability is high in segments with transmural scar on ce-MRI. However, non-enhanced tissue on ce-MRI can represent normal or jeopardized (perfusion-metabolism mismatch) myocardium.