Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany.
Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
World J Biol Psychiatry. 2021 Mar;22(3):214-227. doi: 10.1080/15622975.2020.1775890. Epub 2020 Jul 9.
It is important to find biomarkers associated with transition to illness in individuals at clinical high-risk for psychosis (CHR). Here, we use free-water imaging, an advanced diffusion MRI technique, to identify white matter alterations in the brains of CHR subjects who subsequently develop psychosis (CHR-P) compared to those who do not (CHR-NP).
Twenty-four healthy controls (HC) and 30 CHR individuals, 8 of whom converted to schizophrenia after a mean follow-up of 15.16 months, received baseline MRI scans. Maps of fractional anisotropy (FA), FA of cellular tissue (FA), and extracellular free-water (FW) were extracted using tract-based spatial statistics after which voxel-wise non-parametric group statistics and correlations with symptom severity were performed.
There were no significant differences between HCs and the combined CHR group. However, prior to conversion, CHR-P showed widespread lower FA compared to CHR-NP ( < 0.05). FA changes in CHR-P were associated with significantly lower FA and higher FW, compared to CHR-NP. Positive symptoms correlated significantly with diffusion parameters in similar regions as those discriminating CHR-P from CHR-NP.
Our study suggests that cellular (FA) and extracellular (FW) white matter alterations are associated with positive symptom severity and indicate an elevated illness risk among CHR individuals.
在处于精神病临床高风险（CHR）的个体中，找到与疾病进展相关的生物标志物非常重要。在这里，我们使用自由水成像（一种先进的扩散 MRI 技术），来识别随后发展为精神病（CHR-P）的 CHR 受试者的大脑中的白质改变，与那些没有发展为精神病（CHR-NP）的受试者进行比较。
24 名健康对照（HC）和 30 名 CHR 个体，其中 8 名在平均 15.16 个月的随访后发展为精神分裂症，接受了基线 MRI 扫描。使用基于束的空间统计学提取各向异性分数（FA）、细胞组织各向异性分数（FA）和细胞外自由水（FW）图，然后进行基于体素的非参数组统计和与症状严重程度的相关性分析。
HC 和联合 CHR 组之间没有显著差异。然而，在转换之前，CHR-P 与 CHR-NP 相比，表现出广泛的 FA 降低（<0.05）。与 CHR-NP 相比，CHR-P 的 FA 变化与显著降低的 FA 和更高的 FW 相关。阳性症状与在区分 CHR-P 和 CHR-NP 的相同区域的扩散参数显著相关。
我们的研究表明，细胞（FA）和细胞外（FW）白质改变与阳性症状严重程度相关，并表明 CHR 个体的疾病风险升高。
