Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Cerebrovasc Dis. 2021;50(3):347-355. doi: 10.1159/000514133. Epub 2021 Mar 17.
Sodium MRI (23Na MRI) derived biomarkers such as tissue sodium concentration (TSC) provide valuable information on cell function and brain tissue viability and has become a reliable tool for the assessment of brain tumors and ischemic stroke beyond pathoanatomical morphology. Patients with major stroke often suffer from different degrees of underlying white matter lesions (WMLs) attributed to chronic small vessel disease. This study aimed to evaluate the WM TSC in patients with an acute ischemic stroke and to correlate the TSC with the extent of small vessel disease. Furthermore, the reliability of relative TSC (rTSC) compared to absolute TSC in these patients was analyzed.
We prospectively examined 62 patients with acute ischemic stroke (73 ± 13 years) between November 2016 and August 2019 from which 18 patients were excluded and thus 44 patients were evaluated. A 3D 23Na MRI was acquired in addition to a T2-TIRM and a diffusion-weighted image. Coregistration and segmentation were performed with SPM 12 based on the T2-TIRM image. The extension of WM T2 hyperintense lesions in each patient was classified using the Fazekas scale of WMLs. The absolute TSC in the WM region was correlated to the Fazekas grades. The stroke region was manually segmented on the coregistered absolute diffusion coefficient image and absolute, and rTSC was calculated in the stroke region and compared to nonischemic WM region. Statistical significance was evaluated using the Student t-test.
For patients with Fazekas grade I (n = 25, age: 68.5 ± 15.1 years), mean TSC in WM was 55.57 ± 7.43 mM, and it was not statistically significant different from patients with Fazekas grade II (n = 7, age: 77.9 ± 6.4 years) with a mean TSC in WM of 53.9 ± 6.4 mM, p = 0.58. For patients with Fazekas grade III (n = 9, age: 81.4 ± 7.9 years), mean TSC in WM was 68.7 ± 10.5 mM, which is statistically significantly higher than the TSC in patients with Fazekas grade I and II (p < 0.001 and p = 0.05, respectively). There was a positive correlation between the TSC in WM and the Fazekas grade with r = 0.48 p < 0.001. The rTSC in the stroke region was statistically significant difference between low (0 and I) and high (2 and 3) Fazekas grades (p = 0.0353) whereas there was no statistically significant difference in absolute TSC in the stroke region between low (0 and I) and high (2 and 3) Fazekas grades.
The significant difference in absolute TSC in WM in patients with severe small vessel disease; Fazekas grade 3 can lead to inaccuracies using rTSC quantification for evaluation of acute ischemic stroke using 23 Na MRI. The study, therefore, emphasizes the importance of absolute tissue sodium quantification.
钠磁共振成像（23Na MRI）衍生的生物标志物，如组织钠浓度（TSC），可提供有关细胞功能和脑组织活力的有价值信息，并且已成为评估脑肿瘤和缺血性中风的可靠工具，超越了病理形态学。患有大中风的患者通常会因慢性小血管疾病而遭受不同程度的潜在白质病变（WML）。本研究旨在评估急性缺血性中风患者的 WM TSC，并将 TSC 与小血管疾病的严重程度相关联。此外，还分析了相对 TSC（rTSC）与这些患者的绝对 TSC 相比的可靠性。
我们前瞻性地检查了 2016 年 11 月至 2019 年 8 月之间的 62 例急性缺血性中风患者（73±13 岁），其中 18 例患者被排除在外，因此评估了 44 例患者。除了 T2-TIRM 和扩散加权图像外，还获得了 3D 23Na MRI。基于 T2-TIRM 图像，使用 SPM 12 进行配准和分割。使用 WML 的 Fazekas 量表对每位患者的 WM T2 高信号病变的扩展进行分类。WM 区域中的绝对 TSC 与 Fazekas 分级相关。在配准的绝对扩散系数图像上手动分割中风区域，并计算绝对 TSC 和 rTSC，并与非缺血性 WM 区域进行比较。使用学生 t 检验评估统计显着性。
对于 Fazekas 分级 I（n = 25，年龄：68.5±15.1 岁）的患者，WM 中的平均 TSC 为 55.57±7.43mM，与 Fazekas 分级 II（n = 7，年龄：77.9±6.4 岁）的患者相比，WM 中的平均 TSC 为 53.9±6.4mM，统计学上无显着差异（p = 0.58）。对于 Fazekas 分级 III（n = 9，年龄：81.4±7.9 岁）的患者，WM 中的平均 TSC 为 68.7±10.5mM，与 Fazekas 分级 I 和 II 的 TSC 相比，统计学上显着更高（p <0.001 和 p = 0.05）。WM 中的 TSC 与 Fazekas 分级之间存在正相关，r = 0.48，p <0.001。低（0 和 I）和高（2 和 3）Fazekas 分级之间的中风区域中的 rTSC 有统计学显着差异（p = 0.0353），而中风区域中的绝对 TSC 在低（0 和 I）和高（2 和 3）Fazekas 分级之间无统计学显着差异。
严重小血管疾病患者 WM 中绝对 TSC 的显着差异；Fazekas 分级 3 可能导致使用 23Na MRI 评估急性缺血性中风时 rTSC 定量不准确。因此，该研究强调了绝对组织钠定量的重要性。
