Tc-99m ethyl cysteinate dimer SPECT and 2-[F-18]fluoro-2-deoxy-D-glucose PET in Alzheimer's disease - Comparison of perfusion and metabolic patterns

Purpose: This study compared Tc-99m ethyl cysteinate dimer (ECD) SPECT images with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) PET images in the same patients with Alzheimer's disease and determined whether ECD SPECT is as useful as FDG PET clinically. Methods: Ten patients with probable Alzheimer's disease (mean +/- SD: age, 71 +/- 5.2 years; 6 women and 4 men; Mini-Mental State Examination score, 19.2 +/- 5.3) were evaluated in this study. Both ECD SPECT and FDG PET were performed within 1.5 months in each patient. Results: ECD SPECT showed a reduction in parietotemporal perfusion in 8 of the 10 patients, whereas FDG PET showed a reduction in temporoparietal metabolism in 9. The ECD images showed greater radiotracer uptake in the cerebellum and occipital lobe than did FDG images. The contrast between the radiotracer uptake in the sensorimotor area and that in the parietotemporal region was not as great in the ECD images as it was in the FDG images. Conclusion: Although ECD SPECT may not be superior to FDG PET, it is useful for the clinical evaluation of patients with Alzheimer's disease.