Evidence of Changes in Brain Tissue Stiffness After Ischemic Stroke Derived From Ultrasound‐Based Elastography

Xu, Zinnia S.; Lee, Rona J.; Chu, Stephanie S.; Yao, Anning; Paun, Marla; Murphy, Seán; Mourad, Pierre D.

doi:10.7863/jum.2013.32.3.485

Cited by 51 publications

(55 citation statements)

References 19 publications

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“…The fact that glutamate has different effects on neurons depending on substrate compliance is an important finding since brain stiffness is altered with injury and glutamate that is released after injury could be beneficial or detrimental, depending on the change in stiffness. Reactive gliosis often occurs after injury, resulting in softening of astrocytes and favoring of dendrite outgrowth after injury .…”

Section: Discussionmentioning

confidence: 99%

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Glutamate affects dendritic morphology of neurons grown on compliant substrates

Previtera

Firestein

2015

Biotechnology Progress

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Brain stiffness changes in response to injury or disease. Similarly, as a secondary consequence, glutamate is released from neurons and astroglia. Two types of glutamate receptors, N-methyl-D-aspartate (NMDA) and α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, sense mechanotransduction, leading to downstream signaling in neurons. Recently, our group reported that these two receptors affect dendrite morphology in hippocampal neurons grown on compliant substrates. Blocking receptor activity has distinct effects on dendrites, depending on whether neurons are grown on soft or stiff gels. In the current study, we examine whether exposure to glutamate itself alters stiffness-mediated changes to dendrites in hippocampal neurons. We find that glutamate augments changes seen when neurons are grown on soft gels of 300 or 600 Pa, but in contrast, glutamate attenuates changes seen when neurons are grown on stiff gels of 3000 Pa. These results suggest that there is interplay between mechanosensing and glutamate receptor activation in determining dendrite morphology in neurons.

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Section: Discussionmentioning

confidence: 99%

“…In disease states and during repair, the overall stiffness of the brain changes. For example, brain stiffness decreases in Alzheimer's Disease, during demyelination, and after stroke . In contrast, neurogenesis is thought to increase brain stiffness .…”

Section: Introductionmentioning

confidence: 99%

Glutamate affects dendritic morphology of neurons grown on compliant substrates

Previtera

Firestein

2015

Biotechnology Progress

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“…These changes in stiffness were attributed to the formation of edema and necrosis on the ipsilateral hemisphere and a decrease in regional blood flow on the contralateral hemisphere. Based on the previous studies, tissue stiffness is apparently related to the degree of fluid within the tissue (ie, higher fluid content leads to decreased tissue stiffness) …”

Section: Ultrasound Elastographymentioning

confidence: 99%

Contrast‐Enhanced Ultrasound and Elastography Imaging of the Neonatal Brain: A Review

Bailey

Huisman

Jong

et al. 2017

Journal of Neuroimaging

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Neonates presenting with neurologic symptoms require rapid, noninvasive imaging with high spatial resolution and tissue contrast. Magnetic resonance imaging (MRI) is currently the most sensitive and specific imaging modality for evaluation of neurological pathology. This modality does come with several challenges in the neonatal population, namely, the need to transport a possibly critically sick neonate to the MRI suite and the necessity of the neonate to remain still for a significant length of time, occasionally requiring sedation. Cranial ultrasound has provided radiologists and clinicians with an invaluable imaging modality that allows of rapid, bedside point of care evaluation without ionizing radiation. The major drawback of cranial ultrasound is its lower sensitivity and specificity for subtle/early lesions. Contrast-enhanced ultrasound (CEUS) and elastography have the potential to improve sensitivity and specificity for a variety of neuropathology but also expand the indications for cranial ultrasound. Goal of this paper is to present and discuss CEUS and elastography for neonatal brain imaging.

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“…Thus, an artificial slip interface can be seen on both the shear line images and OSS maps as a result of the large wave amplitude within the edema. This higher wave amplitude could be explained by decreased stiffness of brain parenchyma from increased fluid content in the region of edema, possibly resulting in some loss of tissue structural integrity 13. Therefore, normalizing OSS maps to the wave amplitude can partially remove this effect of amplitude variation within these regions, and provide a more accurate prediction of a non‐slip interface in the setting of peritumoral edema.…”

Section: Discussionmentioning

confidence: 99%

Slip interface imaging based on MR‐elastography preoperatively predicts meningioma–brain adhesion

Yin

Hughes

Glaser

et al. 2017

Magnetic Resonance Imaging

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PurposeTo investigate the ability of slip interface imaging (SII), a recently developed magnetic resonance elastography (MRE)‐based technique, to predict the degree of meningioma–brain adhesion, using findings at surgery as the reference standard.Materials and MethodsWith Institutional Review Board approval and written informed consent, 25 patients with meningiomas >2.5 cm in maximal diameter underwent preoperative SII assessment. Intracranial shear motions were introduced using a soft, pillow‐like head driver and the resulting displacement field was acquired with an MRE pulse sequence on 3T MR scanners. The displacement data were analyzed to determine tumor–brain adhesion by assessing intensities on shear line images and raw as well as normalized octahedral shear strain (OSS) values along the interface. The SII findings of shear line images, OSS, and normalized OSS were independently and blindly correlated with surgical findings of tumor adhesion by using the Cohen's κ coefficient and chi‐squared test.ResultsNeurosurgeons categorized the surgical plane as extrapial (no adhesion) in 15 patients, mixed in four, and subpial (adhesion) in six. Both shear line images and OSS agreed with the surgical findings in 18 (72%) cases (fair agreement, κ = 0.37, 95% confidence interval [CI]: 0.05–0.69), while normalized OSS was concordant with the surgical findings in 23 (92%) cases (good agreement, κ = 0.86, 95% CI: 0.67–1). The correlation between SII predictions (shear line images, OSS, and normalized OSS) and the surgical findings were statistically significant (chi‐squared test, P = 0.02, P = 0.02, and P < 0.0001, respectively).ConclusionSII preoperatively evaluates the degree of meningioma–brain adhesion noninvasively, allowing for improved prediction of surgical risk and tumor resectability. Level of Evidence: 1 Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2017;46:1007–1016.

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Evidence of Changes in Brain Tissue Stiffness After Ischemic Stroke Derived From Ultrasound‐Based Elastography

Cited by 51 publications

References 19 publications

Glutamate affects dendritic morphology of neurons grown on compliant substrates

Glutamate affects dendritic morphology of neurons grown on compliant substrates

Contrast‐Enhanced Ultrasound and Elastography Imaging of the Neonatal Brain: A Review

Slip interface imaging based on MR‐elastography preoperatively predicts meningioma–brain adhesion

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