Methodologies for task-fMRI based prognostic biomarkers in response to aphasia treatment

Song, Serena E.; Krishnamurthy, Lisa C.; Rodriguez, Amy D.; Han, Joo H.; Crosson, Bruce A.; Krishnamurthy, Venkatagiri

doi:10.1016/j.bbr.2023.114575

Cited by 2 publications

(1 citation statement)

References 51 publications

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“…We recently established that whole-brain task-fMRI data can be used to quantify brain-behavior maps in PWA ( Song et al, 2023 ). Based on these promising results, we built upon this multi-variate framework by using whole-brain CBF maps.…”

Section: Methodsmentioning

confidence: 99%

ASL MRI informs blood flow to chronic stroke lesions in patients with aphasia

et al. 2023

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Introduction: 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.Methods: 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.Results: 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.Discussion: 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.

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Section: Methodsmentioning

confidence: 99%

ASL MRI informs blood flow to chronic stroke lesions in patients with aphasia

et al. 2023

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Global Impact of Aging on the Hemodynamic Response Function in the Gray Matter of Human Cerebral Cortex

Fesharaki,

Taylor,

Mosby

et al. 2024

Human Brain Mapping

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In functional magnetic resonance imaging, the hemodynamic response function (HRF) is a stereotypical response to local changes in cerebral hemodynamics and oxygen metabolism due to briefly (< 4 s) evoked neural activity. Accordingly, the HRF is often used as an impulse response with the assumption of linearity in data analysis. In cognitive aging studies, it has been very common to interpret differences in brain activation as age‐related changes in neural activity. Contrary to this assumption, however, evidence has accrued that normal aging may also significantly affect the vasculature, thereby affecting cerebral hemodynamics and metabolism, confounding interpretation of fMRI cognitive aging studies. In this study, use was made of a multisensory task to evoke the HRF in ~87% of cerebral cortex in cognitively intact adults with ages ranging from 22 to 75 years. This widespread activation enabled us to investigate age trends in the spatial distributions of HRF characteristics within the majority of cortical gray matter, which we termed as global age trends. The task evoked both positive and negative HRFs, which were characterized using model‐free parameters in native‐space coordinates. We found significant global age trends in the distributions of HRF parameters in terms of both amplitudes (e.g., peak amplitude and contrast‐to‐noise ratio) and temporal dynamics (e.g., full‐width‐at‐half‐maximum). Our findings offer insight into how age‐dependent changes affect neurovascular coupling and show promise for use of HRF parameters as non‐invasive indicators for age‐related pathology.

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Methodologies for task-fMRI based prognostic biomarkers in response to aphasia treatment

Cited by 2 publications

References 51 publications

ASL MRI informs blood flow to chronic stroke lesions in patients with aphasia

ASL MRI informs blood flow to chronic stroke lesions in patients with aphasia

Global Impact of Aging on the Hemodynamic Response Function in the Gray Matter of Human Cerebral Cortex

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