Woitek Ramona, Prayer Daniela, Weber Michael, Amann Gabriele, Seidl Rainer, Bettelheim Dieter, Schöpf Veronika, Brugger Peter C, Furtner Julia, Asenbaum Ulrika, Kasprian Gregor
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringerguertel 18-20, 1090, Vienna, Austria.
Department of Clinical Pathology, Medical University of Vienna, Vienna, Austria.
Eur Radiol. 2016 May;26(5):1274-83. doi: 10.1007/s00330-015-3939-1. Epub 2015 Sep 2.
This prenatal MRI study evaluated the potential of diffusion tensor imaging (DTI) metrics to identify changes in the midbrain of fetuses with Chiari II malformations compared to fetuses with mild ventriculomegaly, hydrocephalus and normal CNS development.
Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from a region of interest (ROI) in the midbrain of 46 fetuses with normal CNS, 15 with Chiari II malformations, eight with hydrocephalus and 12 with mild ventriculomegaly. Fetuses with different diagnoses were compared group-wise after age-matching. Axial T2W-FSE sequences and single-shot echo planar DTI sequences (16 non-collinear diffusion gradient-encoding directions, b-values of 0 and 700 s/mm(2), 1.5 Tesla) were evaluated retrospectively.
In Chiari II malformations, FA was significantly higher than in age-matched fetuses with a normal CNS (p = .003), while ADC was not significantly different. No differences in DTI metrics between normal controls and fetuses with hydrocephalus or vetriculomegaly were detected.
DTI can detect and quantify parenchymal alterations of the fetal midbrain in Chiari II malformations. Therefore, in cases of enlarged fetal ventricles, FA of the fetal midbrain may contribute to the differentiation between Chiari II malformation and other entities.
• FA in the fetal midbrain is elevated in Chiari II malformations. • FA is not elevated in hydrocephalus and mild ventriculomegaly without Chiari II. • Measuring FA may help distinguish different causes for enlarged ventricles prenatally. • Elevated FA may aid in the diagnosis of open neural tube defects. • Elevated FA might contribute to stratification for prenatal surgery in Chiari II.
本产前磁共振成像（MRI）研究评估了弥散张量成像（DTI）指标在识别患有Chiari II型畸形胎儿中脑变化方面的潜力，并与轻度脑室扩大、脑积水及中枢神经系统（CNS）发育正常的胎儿进行比较。
对46例CNS正常的胎儿、15例患有Chiari II型畸形的胎儿、8例患有脑积水的胎儿以及12例患有轻度脑室扩大的胎儿，计算其脑中线感兴趣区（ROI）的分数各向异性（FA）和表观扩散系数（ADC）。对不同诊断的胎儿进行年龄匹配后，按组进行比较。回顾性评估轴向T2加权快速自旋回波（T2W-FSE）序列和单次激发回波平面DTI序列（16个非共线扩散梯度编码方向，b值为0和700 s/mm²，1.5特斯拉）。
在Chiari II型畸形中，FA显著高于年龄匹配的CNS正常胎儿（p = 0.003），而ADC无显著差异。未检测到正常对照组与脑积水或脑室扩大胎儿之间DTI指标的差异。
DTI可检测并量化Chiari II型畸形胎儿中脑的实质改变。因此，在胎儿脑室扩大的情况下，胎儿中脑的FA可能有助于鉴别Chiari II型畸形与其他病变。
• Chiari II型畸形胎儿中脑的FA升高。• 无Chiari II型畸形的脑积水和轻度脑室扩大中FA不升高。• 测量FA可能有助于产前区分脑室扩大的不同原因。• FA升高可能有助于开放性神经管缺陷的诊断。• FA升高可能有助于Chiari II型畸形产前手术的分层。
