Department of Pediatric Neurosurgery, Medical University of Silesia, Katowice, Poland.
Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland.
World Neurosurg. 2021 Aug;152:124-136. doi: 10.1016/j.wneu.2021.06.052. Epub 2021 Jun 17.
Diffusion tensor imaging (DTI) application in Chiari malformation type I (CMI) is still poorly defined. This study aimed to systematically review the literature and propose perspectives toward the clinical application of DTI in CMI.
PubMed and Embase were searched for English-language articles published until October 20, 2020. Clinical studies and case series, evaluating fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), or radial diffusivity values in patients with CMI, were included.
Eight articles were included. Lower FA values were found at the syrinx level, which decreased with syrinx extent and intensity of symptoms, reflecting myelopathy severity. Decreased AD and MD in the middle cerebellar peduncles in symptomatic patients with CMI might explain the presence of cerebellar signs. Increased FA in various supratentorial structures positively correlated with pain severity. Worse performance in neuropsychological tests correlated with decreased FA, increased MD, and radial diffusivity, reflecting axonal degeneration. Postoperative FA decrease in the brainstem compression area reflects successful decompression. A positive correlation was found between the extent of tonsillar ectopia and increased FA, MD, and AD values, which could act as an early indicator of acute brainstem compression.
DTI might provide a valuable insight into the neurobiological foundation of symptomatic CMI presentation. The severity of white matter injury evident on DTI could serve as a reliable predictor of postoperative outcomes, therefore facilitating selection of appropriate surgical candidates. Postinterventional DTI reassessment might enable differentiation between unsuccessful surgical technique and irreversible myelopathy. The extent of tonsillar ectopia reflects the severity of microstructural brainstem injury.
弥散张量成像（DTI）在 Chiari 畸形 I 型（CMI）中的应用仍未得到充分定义。本研究旨在系统地回顾文献，并提出 DTI 在 CMI 中的临床应用前景。
检索 2020 年 10 月 20 日之前发表的英文文献，纳入评估 CMI 患者胼胝体下疝水平各向异性分数（FA）、平均弥散系数（MD）、轴向弥散系数（AD）和径向弥散系数值的临床研究和病例系列。
共纳入 8 篇文章。在有症状的 CMI 患者中，小脑蚓部 FA 值降低，且与脊髓空洞范围和严重程度相关，反映了脊髓病的严重程度。中脑小脑脚 AD 和 MD 降低可能解释了小脑体征的存在。在存在疼痛的患者中，不同的幕上结构 FA 值增加与疼痛严重程度呈正相关。神经心理学测试表现较差与 FA 值降低、MD 值增加和径向弥散系数增加相关，反映了轴突变性。脑干受压区术后 FA 值降低反映了减压成功。小脑扁桃体下疝程度与 FA 值、MD 值和 AD 值增加呈正相关，可能作为急性脑干压迫的早期指标。
DTI 可能为有症状 CMI 表现的神经生物学基础提供有价值的见解。DTI 上可见的白质损伤严重程度可作为术后结局的可靠预测指标，从而有助于选择合适的手术患者。术后 DTI 再评估可能有助于区分手术技术失败和不可逆性脊髓病。小脑扁桃体下疝程度反映了脑干微观结构损伤的严重程度。
