Vita-Salute San Raffaele University, Milan, Italy.
Neurobiol Dis. 2010 Feb;37(2):468-76. doi: 10.1016/j.nbd.2009.11.003. Epub 2009 Nov 11.
Obsessive-compulsive disorder (OCD) is thought to involve large-scale brain systems but the anatomical connectivity via association fibers has not been specifically investigated yet. We evaluated organization and directionality of the major fiber bundles in a subpopulation of OCD, including washers and checkers who presented decision making deficits, by measuring MRI parameters related to water self-diffusion (Fractional Anisotropy, FA) and fiber directionality (Principal Diffusion Direction, PDD) in 15 OCD and 16 control subjects. OCD patients showed significantly lower FA and altered PDD along the corpus callosum, cingulum, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus bilaterally. The track-based analysis of the inferior fronto-occipital fasciculus confirmed a significant bilateral FA reduction. Lower FA values in the inferior fronto-occipital fasciculus, superior longitudinal fasciculus and corpus callosum correlated with symptom severity and neuropsychological performance. This multi-parameter MRI study revealed specific white matter abnormalities in OCD suggesting tract disorganization as main feature, reflected by local changes in fiber directionality. This altered anatomical connectivity might play a specific role in OCD pathophysiology.
强迫症（OCD）被认为涉及大脑的大范围系统，但尚未具体研究通过联合纤维的解剖连通性。我们通过测量与水自扩散（各向异性分数，FA）和纤维方向（主扩散方向，PDD）相关的 MRI 参数，评估了包括决策者在内的 OCD 亚群中主要纤维束的组织和方向性，在 15 名 OCD 和 16 名对照受试者中。OCD 患者的胼胝体、扣带、上纵束和下额枕束双侧 FA 值明显降低，PDD 改变。下额枕束的基于轨迹的分析证实双侧 FA 明显减少。下额枕束、上纵束和胼胝体的 FA 值降低与症状严重程度和神经心理学表现相关。这项多参数 MRI 研究显示 OCD 存在特定的白质异常，表明束结构紊乱是主要特征，反映了纤维方向的局部变化。这种改变的解剖连通性可能在 OCD 的病理生理学中发挥特定作用。
