Brain Tissue Pulsation in Healthy Volunteers

Turner, Poppy; Banahan, Caroline; Alharbi, Meshal; Ince, Jonathan; Venturini, Sara; Berger, Stefanie; Bnini, Imane; Campbell, James; Beach, Kirk W.; Horsfield, Mark A.; Oura, Mitsuhiro; Lecchini‐Visintini, Andrea; Chung, Emma

doi:10.1016/j.ultrasmedbio.2020.08.020

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…MRI BTP amplitude estimates broadly agree with a previous ultrasound study by Turner et al [12] who examined 107 healthy subjects and found a BTP amplitude of ~ 0.16 mm at a depth of 7.6 cm beneath the forehead, reducing to ~ 0.1 mm at a depth of 2.2 cm. Weaver et al [18] examined 6 patients and found that BTP amplitude was approximately 0.15 mm close to the circle of Willis compared to 0.1 mm at the brain peripheries.…”

Section: Discussionsupporting

confidence: 89%

“…A previous systematic review by Ince et al focused on the use of ultrasound for measuring BTPs and hypothesised there may be an effect of cerebral pathophysiology on brain motion [2]. Since then, additional literature has allowed further exploration of the effect of pathology on brain motion, including a healthy volunteer study of 107 participants [12] and a study measuring BTP transcranial tissue Doppler (TCTD) measurements in acute stroke.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging of the pulsing brain: a systematic review

Almudayni

Alharbi

Chowdhury

et al. 2022

Magn Reson Mater Phy

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Objective To perform a systematic review of the literature exploring magnetic resonance imaging (MRI) methods for measuring natural brain tissue pulsations (BTPs) in humans. Methods A prospective systematic search of MEDLINE, SCOPUS and OpenGrey databases was conducted by two independent reviewers using a pre-determined strategy. The search focused on identifying reported measurements of naturally occurring BTP motion in humans. Studies involving non-human participants, MRI in combination with other modalities, MRI during invasive procedures and MRI studies involving externally applied tests were excluded. Data from the retrieved records were combined to create Forest plots comparing brain tissue displacement between Chiari-malformation type 1 (CM-I) patients and healthy controls using an independent samples t-test. Results The search retrieved 22 eligible articles. Articles described 5 main MRI techniques for visualisation or quantification of intrinsic brain motion. MRI techniques generally agreed that the amplitude of BTPs varies regionally from 0.04 mm to ~ 0.80 mm, with larger tissue displacements occurring closer to the centre and base of the brain compared to peripheral regions. Studies of brain pathology using MRI BTP measurements are currently limited to tumour characterisation, idiopathic intracranial hypertension (IIH), and CM-I. A pooled analysis confirmed that displacement of tissue in the cerebellar tonsillar region of CM-I patients was + 0.31 mm [95% CI 0.23, 0.38, p < 0.0001] higher than in healthy controls. Discussion MRI techniques used for measurements of brain motion are at an early stage of development with high heterogeneity across the methods used. Further work is required to provide normative data to support systematic BTPs characterisation in health and disease.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging of the pulsing brain: a systematic review

Almudayni

Alharbi

Chowdhury

et al. 2022

Magn Reson Mater Phy

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“…A limitation of our study is that we were unable to alter EtCO 2 without simultaneously inducing changes in other potential confounders such as PP and HR. In a previous cross-sectional study, it was found that participants with higher pulse pressure had significantly higher BTPs; a 1% higher blood pressure was associated with a 0.8% higher Bulk BTP amplitude [ 15 ]. Visual inspection of trends within our data also suggest Bulk BTP amplitude may be positively correlated with PP and HR.…”

Section: Discussionmentioning

confidence: 99%

The Effects of Hypocapnia on Brain Tissue Pulsations

et al. 2020

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Hypocapnia is known to affect patients with acute stroke and plays a key role in governing cerebral autoregulation. However, the impact of hypocapnia on brain tissue pulsations (BTPs) is relatively unexplored. As BTPs are hypothesised to result from cerebrovascular resistance to the inflow of pulsatile arterial blood, it has also been hypothesised that cerebral autoregulation changes mediated by hypocapnia will alter BTP amplitude. This healthy volunteer study reports measurements of BTPs obtained using transcranial tissue Doppler (TCTD). Thirty participants underwent hyperventilation to induce mild hypocapnia. BTP amplitude, EtCO2, blood pressure, and heart rate were then analysed to explore the impact of hypocapnia on BTP amplitude. Significant changes in BTP amplitude were noted during recovery from hypocapnia, but not during the hyperventilation manoeuvre itself. However, a significant increase in heart rate and pulse pressure and decrease in mean arterial pressure were also observed to accompany hypocapnia, which may have confounded our findings. Whilst further investigation is required, the results of this study provide a starting point for better understanding of the effects of carbon dioxide levels on BTPs. Further research in this area is needed to identify the major physiological drivers of BTPs and quantify their interactions with other aspects of cerebral haemodynamics.

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