Microstructural Hippocampal Alterations in Alzheimer's Disease: A Systematic Review and Meta-Analysis of Diffusion Kurtosis Imaging

IF 2.7 3区心理学 Q2 BEHAVIORAL SCIENCES

Brain and Behavior Pub Date : 2025-09-21 DOI:10.1002/brb3.70919

Amir Mahmoud Ahmadzadeh, Sadegh Ghaderi, Sana Mohammadi, Nahid Jashirenezhad, Farzad Fatehi

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Abstract

Background

The hippocampus is highly vulnerable in Alzheimer's disease (AD), with early microstructural changes potentially detectable via diffusion kurtosis imaging (DKI). Previous studies report promising DKI findings in AD, necessitating systematic evaluation. To compare hippocampal DKI metrics, particularly mean kurtosis (MK), between AD patients and healthy controls (HCs) and explore factors influencing these differences.

Methods

Following PRISMA guidelines, PubMed, Scopus, Web of Science, and Embase were searched until November 2024. Two reviewers independently extracted hippocampal MK values. Risk of bias was evaluated using the Newcastle–Ottawa Scale. Meta-analysis employed random-effects models (STATA v17). Subgroup analyses (sex, age, magnetic resonance imaging [MRI] parameters) and sensitivity and trim-and-fill assessments were conducted. Standardized mean difference (SMD), I² for heterogeneity, and Egger's/Begg's tests for publication bias (significance: p < 0.05).

Results

Ten studies (215 AD patients, 217 HCs; mean age: 65–75 years) using 3.0 T MRI were included. Eight articles were included in the meta-analysis to compare MK between groups. AD patients exhibited significantly reduced bilateral hippocampal MK compared to HCs (left: SMD = −1.32, 95% confidence interval [95% CI] [−1.97 to −0.66]; right: SMD = −1.22 [−1.88 to −0.56]; both p < 0.001), indicating compromised microstructural complexity. Subgroup analyses revealed more pronounced MK reductions in studies with higher male ratios (>42%; left: SMD = −1.87; right: SMD = −1.91; p < 0.05). Age, echo time, repetition time, and diffusion directions did not significantly influence effect sizes. Sensitivity analyses confirmed robustness, and publication bias was detected, but trim-and-fill analyses revealed no missing studies.

Conclusion

Reduced hippocampal MK in AD reflects microstructural degeneration, with sex-related differences in effect magnitude.

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阿尔茨海默病海马微结构改变：弥散峰度成像的系统回顾和荟萃分析

海马在阿尔茨海默病（AD）中非常脆弱，通过弥散峰度成像（DKI）可以检测到早期微结构变化。先前的研究报告了在AD中有希望的DKI发现，需要进行系统评估。比较AD患者和健康对照（hc）的海马DKI指标，特别是平均峰度（MK），并探讨影响这些差异的因素。方法按照PRISMA指南，检索PubMed、Scopus、Web of Science和Embase，检索时间截止到2024年11月。两名评论者独立提取了海马的MK值。偏倚风险采用纽卡斯尔-渥太华量表进行评估。meta分析采用随机效应模型（STATA v17）。进行亚组分析（性别、年龄、磁共振成像[MRI]参数）、敏感性和修整填充评估。标准化平均差（SMD）， I2表示异质性，Egger’s/Begg’s检验表示发表偏倚（显著性：p <； 0.05）。结果10项研究（215例AD患者，217例hc患者，平均年龄：65-75岁）采用3.0 T MRI。meta分析纳入8篇文章，比较两组间的MK。与hc相比，AD患者的双侧海马MK显著降低（左：SMD = - 1.32, 95%可信区间[95% CI][- 1.97至- 0.66]；右：SMD = - 1.22[- 1.88至- 0.56];p < 0.001），表明微结构复杂性受损。亚组分析显示，在男性比例较高的研究中，MK降低更为明显（>42%；左：SMD = - 1.87；右：SMD = - 1.91; p < 0.05）。年龄、回声时间、重复时间和扩散方向对效应量无显著影响。敏感性分析证实了稳健性，并发现了发表偏倚，但修正填充分析未发现缺失研究。结论阿尔茨海默病海马MK降低反映了微结构变性，其影响程度存在性别差异。

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来源期刊

Brain and Behavior BEHAVIORAL SCIENCES-NEUROSCIENCES

CiteScore

5.30

自引率

0.00%

发文量

352

审稿时长

14 weeks

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