ABSTRACT
Objective To evaluate the diagnostic value of brain SPECT imaging with a novel Aβ plaque probe,131 I-2-(4'-dimethylaminophenyl) -6-iodoimidazo[ 1,2-α ] pyridine ( 131 I-IMPY) in early AD.Methods Thirteen patients with AD (3 males,10 females,age ranged 52 - 79 y),11 with mild cognitive impairment (MCI,4 males,7 females,age ranged 48 - 67 y) and 14 normal controls (6 males,8 females,age ranged 42 - 67 y) were enrolled in this study.131I-IMPY SPECT imaging was acquired in 2 -3 h after the agent injection.ROIs were drawn on cerebral lobes and cerebellum.The ratios of mean radioactivity of cerebral lobes over cerebellum (Rcl/cb) were calculated.The t-test was used for data analysis.Results In patients with MCI,Rcl/cb ratios were increased in parietal gyrus,temporal gyrus and frontal gyrus (right:1.15±0.18,1.18±0.12,1.14±0.14; left:1.16±0.11,1.19±0.18,1.15±0.09)compared with those in normal control group ( right:1.02 ± 0.12,1.05 ± 0.14,1.01 ± 0.12 ; left:1.03 ±0.13,1.05 ±0.13,1.01 ±0.14; t:2.1642 to 2.8757,all P ＜0.05).Rcl/cb ratios of basel ganglia and occipital gyms in MCI group (right:0.92 ±0.18,1.12 ±0.15; left:0.94 ±0.15,1.13 ±0.17) showed no statistical difference compared with those in normal control group (right:0.82 ±0.15,1.06 ±0.18;left:0.85 ±0.16,1.08 ±0.15; t:0.7805 to 1.4344,all P＞0.05).In patients with AD,Rcl/cb ratios were increased in parietal,temporal,basal ganglia and occipital lobes (right:1.16 ±0.19,1.24 ±0.17,1.16 ±0.13,1.14±0.11,1.23±0.10; left:1.17±0.21,1.25±0.15,1.18±0.08,1.17±0.16,1.25±0.11)compared with those in normal control group( t:2.1001 to 6.2789,all P ＜0.05).Rcl/cb ratios of parietal,temporal and frontal lobes in AD group showed no statistical difference compared with those in MCI group (t:0.1316 to 0.9806,all P ＞ 0.05 ),while Rcl/cb ratios of basal ganglia and occipital lobes in AD group were increased compared with those in MCI group ( t:2.0850 to 3.6772,all P ＜ 0.05 ).Conclusion 131 I-IMPY as a β- amyloid plaque probe for brain SPECT imaging may be potentially helpful for early diagnosis of AD.