During aging, human white matter (WM) is subject to dynamic structural changes which have a deep impact on healthy and pathological evolution of the brain through the lifespan; characterizing this pattern is of key importance for understanding brain development, maturation, and aging as well as for studying its pathological alterations. Diffusion magnetic resonance imaging (MRI) can provide a quantitative assessment of the white-matter microstructural organization that characterizes these trajectories. Here, we use both conventional and advanced diffusion MRI in a cohort of 91 individuals (age range: 13-62 years) to study region- and sex-specific features of WM microstructural integrity in healthy aging. We focus on the age at which microstructural imaging parameters invert their development trend as the time point which marks the onset of microstructural decline in WM. Importantly, our results indicate that age-related brain changes begin earlier in males than females and affect more frontal regions-in accordance with evolutionary theories and numerous evidences across non-MRI domains. Advanced diffusion MRI reveals age-related WM modification patterns which cannot be detected using conventional diffusion tensor imaging.

中文翻译：

---

多壳扩散成像揭示了正常衰老中早期白质变性的性别特异性轨迹

在衰老过程中，人类白质 (WM) 会发生动态结构变化，这对大脑在整个生命周期中的健康和病理进化具有深远的影响；表征这种模式对于理解大脑发育、成熟和衰老以及研究其病理改变至关重要。弥散磁共振成像 (MRI) 可以对表征这些轨迹的白质微观结构组织进行定量评估。在这里，我们在 91 人（年龄范围：13-62 岁）的队列中使用传统和先进的扩散 MRI 来研究健康老龄化过程中 WM 微观结构完整性的区域和性别特异性特征。我们关注微结构成像参数反转其发展趋势的年龄，作为标志着 WM 微结构下降开始的时间点。重要的是，根据进化理论和非 MRI 领域的大量证据，我们的结果表明，与年龄相关的大脑变化在男性中比女性更早开始并影响更多的额叶区域。高级扩散 MRI 揭示了使用传统扩散张量成像无法检测到的与年龄相关的 WM 修改模式。