Abstract 512: Usefulness of 123I-BMIPP/201TlCl Dual Myocardial SPECT in Patients With Low Ejection Fraction of Uncertain Cause
[Introduction] Distinction of ischemic cardiomyopathy (ICM) from nonischemic cardiomyopathy (NICM) is important in patients with low ejection fraction (EF) of uncertain cause. Use of 123I-BMIPP/201TlCl dual myocardial SPECT (Dual SPECT) permits noninvasive detection of myocardial disorder due to ischemia. However, it remains unclear whether we can distinguish ICM from NICM by this imaging technique.
[Hypothesis] We tested the hypothesis that Dual SPECT is useful to distinguish ICM from NICM.
[Method] We studied 425 consecutive patients (313 males, mean age 67±12 years) who were admitted because of heart failure for the first time between April 2005 to April 2009. Coronary angiography or coronary CT angiography was performed after Dual SPECT. Polar map was divided into 17 segments, and average percent uptake of each segment was calculated. Defect and mismatch on 123BMIPP and 201TlCl images were scored on a scale of 0 – 4, based on segmental percent uptake. Normal range for each segment was obtained from normal patients (quantitative analysis). The Dual SPECT images were also evaluated visually by three cardiologists for whether the extent of defect or mismatch coincides with the territory of coronary arteries (qualitative analysis).
[Results] Total defect scores were significantly higher in ICM compared with NICM on both 201TlCl (15.3±10.6 versus 8.09±7.48, p<0.05) and 123I-BMIPP (14.7±10.9 versus 5.78±7.17, p<0.05) images, but it was not possible to distinguish ICM from NICM by the defect score. In almost all patients with ICM, the extent of defect on 123I-BMIPP was wider than that on 201TlCI in polar map. And the mismatch score (123I-BMIPP defect score - 201TlCI defect score) was significantly different between ICM and NICM (2.7±2.4 versus 0.8±1.8, p<0.05). Multivariate analysis revealed that mismatch score was an independent factor related to ICM. According to qualitative analysis, positive and negative predictive values were 86% and 98% respectively.
[Conclusion] Dual SPECT demonstrates that ICM has more severe perfusion and metabolic disturbance compared with NICM. Furthermore the mismatch between 201TlCl and 123I-BMIPP uptake is useful in differential diagnosis of ICM and NICM.