Prediction of functional improvement of ischemic myocardium with 123I-BMIPP SPECT and 99mTc-tetrofosmin SPECT imaging: A study of patients with large acute myocardial infarction and receiving revascularization therapy

Abstract

Background: 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) is assumed to be the most useful method of evaluating the viability of the myocardium, but its use is limited by the need for a cyclotron. In the present study, the ability of a combination of 99mTc- tetrofosmin (TF) and 123I-β-methyliodophenyl pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT), a combination of 18F-FDG PET and 123I-BMIPP SPECT, and a combination of 18F-FDG PET and 99mTc-TF SPECT were compared to predict functional improvement of ischemic myocardium after a large acute myocardial infarction (AMI). Methods and Results: Ten patients with large AMI were studied by 99mTc-TF SPECT, 123I-BMIPP SPECT and 18F-FDG PET within 3 weeks. Six months later, 99mTc-TF imaging was performed. All patients underwent successful revascularization, and had no restenosis. Regional tracer uptake was scored using a 4-point scale in 20 segments of the SPECT and PET images. When the defect score of 123I-BMIPP SPECT exceeded the defect score of 99mTc-TF SPECT or 18F-FDG PET by 1 point or more, and when the defect score of 99mTc-TF SPECT exceeded the defect score of 18F-FDG PET by 1 point or more, the segment was considered to show mismatching. When the defect score was the same in 2 tracers, the segment was considered to show matching. 99mTc-TF imaging at 3 weeks and 6 months used quantitative gated SPECT (QGS) to score wall motion using a 6-point scale (-1=dyskinesis, 0=akinesis, 1=severe hypokinesis, 2=moderate hypokinesis, 3=mild hypokinesis, and 4=normokinesis). The sensitivity of the combination of 123I-BMIPP and 99mTc-TF imaging in predicting functional improvement was 61%, that of 18F-FDG PET and 123I-BMIPP SPECT was 94%, and that of 18F-FDG PET and 99mTc-TF SPECT was 76%. The specificity of the combination of 123I-BMIPP and 99mTc-TF imaging in predicting functional improvement was 83%, that of 18F-FDG PET and 123I-BMIPP SPECT was 40%, and that of 18F-FDG PET and 99mTc-TF SPECT was 49%. The accuracy of the combination of 123I-BMIPP and 99mTc-TF imaging in predicting functional improvement was 70%, that of 18F-FDG PET and 123I-BMIPP SPECT was 71%, and that of 18F-FDG PET and 99mTc-TF SPECT was 63%. Conclusion: The combination of 123I-BMIPP and 99mTc-TF imaging is a practical modality for predicting the functional improvement of ischemic myocardium after a large AMI.