• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.112-119
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• 2009

Purpose: This study was performed to investigate the clinical significance of reverse redistribution(RR) phenomenon detected on delayed Tc-99m tetrofosmin myocardial single photon emission computed tomography(SPEG) in patients with acute myocardial infarction after revascularization. Materials and Methods: A Tc-99m tetrofrosmin myocardial SPECT was performed in 67 consecutive patients after revascularization for acute myocardial infarction. Myocardial SPECT imaging was performed for early imaging at 40 min and for delayed imaging at 180 min after reinjection at myocardial stress. Regional myocardial uptakes were scored by 4-point scoring in the left ventricular wall divided into 17 segments. Reverse redistribution was defined as an increase of more than 2 point in the activity score on the delayed image. Follow-up myocardial SPECT and coronary angiography(CAG) were performed 9 months later. Results: On myocardial SPECT performed following revascularization, RR was observed in 100 of all 319 segments(31%) and in 43 patients(64%). The abnormalities of perfusion and regional wall motion were more severe in the patients with RR compared to those without RR(p<0.05). On follow-up myocardial SPECT, the myocardial perfusion, regional wall motion, and myocardial thickness were significantly improved in the patients with RR(p<0.05) however, these changes were not significant in those without RR. There was no significant difference between the patients with RR and those without RR in the occurrence of restenosis on CAG. Conclusions: In patients with acute myocardial infarction, the regions showing the RR phenomenon on delayed Tc-99m tetrofosmin SPECT may reflect viable myocardium and indicate recovery of salvaged myocardium.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.280-286
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• 2009

Purpose: The aim of this study was to evaluate the hemodynamic changes after endovascular stenting in patients with unilateral middle cerebral artery (MCA) stenosis using statistical probabilistic anatomical mapping (SPAM) analysis of basal/acetazolamide (ACZ) Tc-99m ECD brain perfusion SPECT. Materials and Methods: Eight patients (3 men and 5 women, 64.8$\pm$10.5 years) who underwent endovascular stenting for unilateral MCA stenosis were enrolled. Basal/ACZ Tc-99m ECD brain perfusion SPECT studies were performed by one-day protocol before and after stenting. Using SPAM analysis, we compared basal cerebral perfusion (BCP) counts and cerebrovascular reserve (CVR) index of the MCA territory before stenting with those after stenting. Results: After stenting, no patient had any complication nor additional stroke. In SPAM analysis, 7 out of the 8 patients had improved BCP counts of the MCA territory and 7 out of the 8 patients had improved CVR index of the MCA territory after stenting. Before stenting, the mean BCP counts and CVR index in the affected MCA territory were 47.1$\pm$2.2 ml/min/100 g and -2.1$\pm$2.9%, respectively. After stenting, the mean BCP counts and CVR index in the affected MCA territory were improved significantly (48.3$\pm$2.9 ml/min/100 g, p =0.025 and 0.1$\pm$1.3%, p =0.036). Conclusion: This study revealed that SPAM analysis of basal/ACZ brain perfusion SPEG would be helpful to evaluate hemodynamic efficacy of endovascular stenting in unilateral MCA stenosis.