Purpose: Previous studies have demonstrated neuronal dis-integrity in chronic smokers using diffusion tensor imaging (DTI). However, assessment of hippocampal DTI has not been performed in this group. The purpose of this study was to investigate the hippocampal integrity in chronic smokers and non-smokers and to compare this to memory performance.
Methods: We used in vivo DTI to measure the differences in hippocampal integrity between 88 chronic smoker and 88 non-smoking subjects. DTI was performed on a 3T scanner. We administered a verbal learning test to assess new verbal learning capabilities. The immediate recall (IR) was administered immediately after test procedure and delayed recall (DR) after 15min.
Results: Mean values of fractional anisotropy (FA) for non-smokers and smokers were 0.46 and 0.40, respectively (p<0.05). Mean IR word number for non-smokers and smokers was 11.6, 9.04, respectively (p<0.05). The mean word number of DR for non-smokers and smokers was 10.2, 7.2, respectively (p<0.05).
Conclusions: This is the first study of hippocampal DTI assessment in the chronic smokers. We found that decreased hippocampal FA associated with neuronal dis-integrity and worse memory performance in chronic smokers than non-smokers. We also found a low positive correlation hippocampal FA values with memory performance in nonsmoking group.
Keywords: Diffusion tensor; Fractional anisotropy; Hippocampus; Memory; Smoking.
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