Whitehead Matthew T, Raju Anand, Choudhri Asim F
Department of Radiology, University of Tennessee Health Science Center, Memphis, TN, USA,
Neuroradiology. 2014 Apr;56(4):333-8. doi: 10.1007/s00234-014-1323-5. Epub 2014 Jan 26.
Commissural white matter fibers comprising the callosal splenium are diverse. Subsections of the splenium myelinate at different times, in a centrolineal manner. The aims of this study are to depict the normal callosal splenium myelination pattern and to distinguish the transient age-related mid splenium hypointensity from pathology.
We reviewed 131 consecutive brain MRIs in patients between ages 3 and 6 months from a single academic children's hospital. Patients that were preterm, hydrocephalic, and/or had volume loss were excluded. Fifty total MR exams that included T1-weighted MR imaging (T1WI), T2-weighted MR imaging (T2WI), and diffusion tensor imaging (DTI) were reviewed. Regions of callosal splenium myelination manifested by T1 and T2 shortening were evaluated. Tractography was performed with seeds placed over the posterior, mid, and anterior splenium to define the origin, destination, and course of traversing fibers.
Splenium signal varied significantly from 3 to 6 months, with distinct age-related trends. On T1WI, the splenium was hypointense at 3 months (12/13), centrally hypointense/peripherally hyperintense at 4 months (15/16), and hyperintense at 6 months (10/11). Tractography revealed three distinct white matter tract populations: medial occipital (posterior); precuneus, posterior cingulate, and medial temporal (middle); and postcentral gyri (anterior).
Specific commissural fiber components of the splenium myelinate at different times. The transient developmental mid splenium hypointensity on T1WI corresponds to tracts from the associative cortex, principally the precuneus. Heterogeneous splenium signal alteration in patients ages 3-6 months is a normal developmental phenomenon that should not be confused with pathologic lesions.
构成胼胝体压部的连合白质纤维多种多样。压部的各亚段在不同时间以向心线方式髓鞘化。本研究的目的是描绘正常的胼胝体压部髓鞘化模式，并将与年龄相关的短暂性胼胝体中部低信号与病变区分开来。
我们回顾了一家学术性儿童医院连续131例年龄在3至6个月之间患者的脑部MRI。排除早产、脑积水和/或有体积减小情况的患者。共回顾了50例包括T1加权MRI（T1WI）、T2加权MRI（T2WI）和扩散张量成像（DTI）的MR检查。评估了T1和T2缩短所显示的胼胝体压部髓鞘化区域。通过在胼胝体压部的后部、中部和前部放置种子点进行纤维束成像，以确定穿行纤维的起源、终点和走行。
胼胝体压部信号在3至6个月之间有显著变化，呈现出明显的与年龄相关的趋势。在T1WI上，胼胝体压部在3个月时呈低信号（13例中的12例），4个月时中部低信号/周边高信号（16例中的15例），6个月时呈高信号（11例中的10例）。纤维束成像显示出三种不同的白质束群：枕内侧（后部）；楔前叶、后扣带回和颞内侧（中部）；以及中央后回（前部）。
胼胝体压部的特定连合纤维成分在不同时间髓鞘化。T1WI上短暂的发育性胼胝体中部低信号对应于联合皮质的纤维束，主要是楔前叶。3至6个月患者胼胝体压部信号的异质性改变是一种正常的发育现象，不应与病理性病变相混淆。
