Brain-PACE：用于建模纵向大脑加速衰老的深度孪生MRI框架
Brain-PACE: A Deep Siamese MRI Framework for Modelling Longitudinal Brain Acceleration
- University of East Anglia（东英吉利大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
Brain-PACE提出深度孪生MRI框架直接建模纵向脑衰老速度，优于间接估计，关联认知损伤和tau病理，扩展LILAC方法提升性能。
AI中文摘要：
脑龄估计已成为评估大脑健康和疾病的热门研究代理指标，然而大脑衰老的纵向轨迹仍定义不清，临床应用受限。基于现有的孪生纵向框架，我们开发了脑预测年龄加速（Brain-PACE）方法，直接从配对T1加权MRI中估计结构性大脑衰老的速度。Brain-PACE识别出42.6%的轻度认知障碍参与者存在加速衰老。更快的Brain-PACE与更严重的功能和认知障碍（FAQ；r=0.35，ADAS13；r=0.30，CDR-SB；r=0.32）以及后扣带回（r=0.59）、楔前叶（r=0.47）和内嗅皮层（r=0.37）区域tau蛋白负担增加相关。这些关联强于通过重复横断面脑龄估计间接计算衰老速度时所观察到的结果，表明直接纵向建模捕获了与持续病理变化相关的补充信息。在方法上，Brain-PACE扩展了LILAC框架，结合空间注意力、软标签分布学习和Cramér距离目标，提高了概率性能并减少了预测偏差，同时提供了预测不确定性度量。总之，这些发现支持Brain-PACE作为一种互补的纵向影像表型，对早期神经退行性变中相关的临床和生物学变化具有敏感性。
英文摘要：
Brain age estimation has become a popular research proxy for assessing brain health and disease, yet longitudinal trajectories of brain ageing are still poorly defined, and clinical use is limited. Building on existing Siamese longitudinal frameworks, we develop Brain-Predicted Age Acceleration (Brain-PACE) to directly estimate the pace of structural brain ageing from paired T1-weighted MRI. Brain-PACE identified accelerated ageing in $42.6$% of participants with mild cognitive impairment. Faster Brain-PACE was associated with greater functional and cognitive impairment (FAQ; $r=0.35$, ADAS13; $r=0.30$, CDR-SB; $r=0.32$) and greater regional tau burden in the posterior cingulate ($r=0.59$), precuneus ($r=0.47$), and entorhinal cortex ($r=0.37$). These associations were stronger than those observed when pace was calculated indirectly from repeated cross-sectional brain age estimates, suggesting that direct longitudinal modelling captures complementary information relevant to ongoing pathological change. Methodologically, Brain-PACE extends the LILAC framework by combining spatial attention with soft label distribution learning and a Cramér distance objective, improving probabilistic performance and reducing prediction bias while providing measures of predictive uncertainty. Together, these findings support Brain-PACE as a complementary longitudinal imaging phenotype with sensitivity to relevant clinical and biological changes in early neurodegeneration.
