Krishnamurthy Lisa C, Glassman Clara, Han Joo H, Song Serena E, Denmon Chanse, Weatherill Maryanne, Rodriguez Amy D, Crosson Bruce A, Krishnamurthy Venkatagiri
Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Health Care System, Decatur, GA, United States.
Joint GSU, Georgia Tech, and Emory Center for Translational Research in Neuroimaging and Data Science (TReNDS), Atlanta, GA, United States.
Front Physiol. 2023 Jul 20;14:1240992. doi: 10.3389/fphys.2023.1240992. eCollection 2023.
Response to post-stroke aphasia language rehabilitation is difficult to anticipate, mainly because few predictors can help identify optimal, individualized treatment options. Imaging techniques, such as Voxel-based Lesion Symptom Mapping have been useful in linking specific brain areas to language behavior; however, further development is required to optimize the use of structural and physiological information in guiding individualized treatment for persons with aphasia (PWA). In this study, we will determine if cerebral blood flow (CBF) mapped in patients with chronic strokes can be further used to understand stroke-related factors and behavior. We collected perfusion MRI data using pseudo-Continuous Arterial Spin Labeling (pCASL) using a single post-labeling delay of 2,200 ms in 14 chronic PWA, along with high-resolution structural MRI to compute maps of tissue damage using Tissue Integrity Gradation via T2w T1w Ratio (TIGR). To quantify the CBF in chronic stroke lesions, we tested at what point spatial smoothing should be applied in the ASL analysis pipeline. We then related CBF to tissue damage, time since stroke, age, sex, and their respective cross-terms to further understand the variability in lesion CBF. Finally, we assessed the feasibility of computing multivariate brain-behavior maps using CBF and compared them to brain-behavior maps extracted with TIGR MRI. We found that the CBF in chronic stroke lesions is significantly reduced compared to its homologue grey and white matter regions. However, a reliable CBF signal (although smaller than expected) was detected to reveal a negative relationship between CBF and increasing tissue damage. Further, the relationship between the lesion CBF and age, sex, time since stroke, and tissue damage and cross-terms suggested an aging-by-disease interaction. This relationship was strongest when smoothing was applied in the template space. Finally, we show that whole-brain CBF relates to domain-general visuospatial functioning in PWA. The CBF-based brain-behavior maps provide unique and complementary information to structural (lesion-based) brain-behavior maps. Therefore, CBF can be detected in chronic stroke lesions using a standard pCASL MRI acquisition and is informative at the whole-brain level in identifying stroke rehabilitation targets in PWAs due to its relationship with demographic factors, stroke-related factors, and behavior.
中风后失语症语言康复的效果难以预测，主要是因为几乎没有预测指标能够帮助确定最佳的个体化治疗方案。诸如基于体素的病变症状映射等成像技术，在将特定脑区与语言行为联系起来方面很有用；然而，还需要进一步发展，以优化在指导失语症患者（PWA）个体化治疗中对结构和生理信息的利用。在本研究中，我们将确定慢性中风患者中映射的脑血流量（CBF）是否可进一步用于理解与中风相关的因素和行为。我们使用伪连续动脉自旋标记（pCASL），在14名慢性PWA患者中收集灌注MRI数据，单次标记后延迟为2200毫秒，同时采集高分辨率结构MRI，以使用通过T2w/T1w比值的组织完整性分级（TIGR）来计算组织损伤图谱。为了量化慢性中风病灶中的CBF，我们测试了在ASL分析流程中应在哪个点应用空间平滑。然后，我们将CBF与组织损伤、中风后的时间、年龄、性别及其各自的交叉项相关联，以进一步了解病灶CBF的变异性。最后，我们评估了使用CBF计算多变量脑-行为图谱的可行性，并将其与用TIGR MRI提取的脑-行为图谱进行比较。我们发现，与同源的灰质和白质区域相比，慢性中风病灶中的CBF显著降低。然而，检测到一个可靠的CBF信号（尽管比预期小），揭示了CBF与组织损伤增加之间的负相关关系。此外，病灶CBF与年龄、性别、中风后的时间、组织损伤以及交叉项之间的关系表明存在衰老与疾病的相互作用。当在模板空间中应用平滑时，这种关系最为明显。最后，我们表明全脑CBF与PWA患者的一般领域视觉空间功能有关。基于CBF的脑-行为图谱为基于结构（病灶）的脑-行为图谱提供了独特且互补的信息。因此，使用标准的pCASL MRI采集可以在慢性中风病灶中检测到CBF，并且由于其与人口统计学因素、中风相关因素和行为的关系，在全脑水平上对于识别PWA患者的中风康复靶点具有参考价值。
