Harvard Medical School and the Brain Imaging Center, McLean Hospital, Belmont, MA 02478, USA.
J Am Acad Child Adolesc Psychiatry. 2010 Dec;49(12):1260-8. doi: 10.1016/j.jaac.2010.08.015. Epub 2010 Oct 29.
Transverse relaxation time (T2) imaging provides the opportunity to examine membrane fluidity, which can affect a number of cellular functions. The objective of the present work was to examine T2 abnormalities in children with unmodified DSM-IV-TR bipolar disorder (BD) in bilateral cingulate-paracingulate (CPC) white matter.
A total of 21 children and adolescents with BD and 16 healthy control subjects underwent magnetic resonance imaging at 1.5 Tesla and were compared using a region-of-interest analysis. A post hoc diffusion tensor imaging (DTI) analysis was also performed on selected subjects.
The T2 values were significantly decreased on the right-side of the subjects with BD compared with that of the control subjects. Hemispheric difference was also observed in the BD group, with decreased T2 on the right side compared with the left side. No significant difference was observed between left and right CPC T2 in control subjects. For participants who had both T2 and DTI measurements, significant DTI differences were observed: On the left side, fractional anisotropy was reduced and trace and radial diffusivity were increased, whereas on the right side, trace was increased and T2 was decreased in subjects with BD compared with control subjects.
Our findings suggest that the observed T2 difference is a reflection of cerebral blood flow rather than an alteration of the fluidity of cell membranes. It is possible that myelin damage occurs on the left side in early-onset BD, in addition to changes in the blood flow. Prospective studies with larger numbers of subjects are warranted to further explore the relevance of the presented results.
横向弛豫时间（T2）成像提供了检查细胞膜流动性的机会，而细胞膜流动性可能会影响许多细胞功能。本研究旨在探讨未经 DSM-IV-TR 双相障碍（BD）修正的儿童双侧扣带-旁扣带回（CPC）白质中 T2 异常。
共 21 名 BD 儿童和青少年及 16 名健康对照者在 1.5T 磁共振成像仪上进行检查，并使用感兴趣区分析进行比较。对选定的受试者还进行了弥散张量成像（DTI）后分析。
BD 组受试者右侧 T2 值明显低于对照组。BD 组也存在半球差异，右侧 T2 值低于左侧。对照组左右 CPC 的 T2 值无显著差异。对于同时进行 T2 和 DTI 测量的参与者，观察到显著的 DTI 差异：左侧，各向异性分数降低，轨迹和径向弥散度增加，而右侧，BD 组受试者的轨迹增加，T2 值降低。
我们的发现表明，观察到的 T2 差异反映了脑血流量，而不是细胞膜流动性的改变。在早期起病的 BD 中，除了血流变化之外，左侧可能发生髓鞘损伤。需要进行前瞻性的、具有更大样本量的研究，以进一步探讨所呈现结果的相关性。
