4D microvascular imaging based on ultrafast Doppler tomography

3D functional imaging of the whole brain activity during visual task is a challenging task in rodents due to the complex tri-dimensional shape of involved brain regions and the fine spatial and temporal resolutions required to reveal the visual tract. By coupling functional ultrasound (fUS) imaging with a translational motorized stage and an episodic visual stimulation device, we managed to accurately map and to recover the activity of the visual cortices, the Superior Colliculus (SC) and the Lateral Geniculate Nuclei (LGN) in 3D. Cerebral Blood Volume (CBV) responses during visual stimuli were found to be highly correlated with the visual stimulus time profile in visual cortices (r=0.6), SC (r=0.7) and LGN (r=0.7). These responses were found dependent on flickering frequency and contrast, and optimal stimulus parameters for largest CBV increases were obtained. In particular, increasing the flickering frequency higher than 7 Hz revealed a decrease of visual cortices response while the SC response was preserved. Finally, cross-correlation between CBV signals exhibited significant delays (d=0.35 s +/−0.1 s) between blood volume response in SC and visual cortices in response to our visual stimulus. These results emphasize the interest of fUS imaging as a whole brain neuroimaging modality for brain vision studies in rodent models.

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“…1A) that has been previously described in (Demené et al, 2015). The 3D fUS sequence consists in the repetition of the 2D stimulating (Fig.…”

Section: Methodsmentioning

confidence: 99%

3D functional ultrasound imaging of the cerebral visual system in rodents

et al. 2017

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“…To conclude, until a new breakthrough in the field, the MRI use will be limited for micromedical device tracking. Ultrasound waves (Bourdeau et al, ; Demené, Bimbard, et al, ; Demené, Tiran, et al, ; Errico et al, ; Khalil et al, , ; Nikolov & Jensen, ) suffer from attenuation in tissue layers and from reflection at interfaces, limiting the performance trio: invasiveness, position accuracy and depth of use. Recent discoveries enable to break the barrier created by attenuation and reflections, opening a new field of applications called the “neuroimaging” and fitting with micromedical device requirements.…”

Section: Discussionmentioning

confidence: 99%

“…Ultrafast Doppler technology was used to image the thalamus–cortical auditory tract of awake ferrets (Demené, Bimbard, et al, ). The authors exploited the UltraFast Doppler Tomography (UFD‐T) which briefly consists of 2D power Doppler images acquired at 500 Hz (each frame built with 11 tilted plane wave emissions fired at 5,500 Hz) combined with the translation and rotation of the sensor (for more details, see Demené, Tiran, et al, ). They achieved an isotropic 3D resolution of 100 μm in a total volume of 14 × 14 × 20 mm 3 (Figure ).…”

Section: Existing Tracking Systemsmentioning

confidence: 99%

Tracking systems for intracranial medical devices: A review

François

Duplat²,

Haliyo

et al. 2019

Med Devices & Sens

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In minimally invasive surgery, especially in neurosurgery, the ability to reach deep and functional structures without damage remains a major challenge. Recent breakthroughs in microtechnologies have enabled the downsizing of an increasing number of devices. In such a context, the possibility to navigate a micromedical device inside the human brain is a reachable ambition. One of the most expected applications is the identification and the treatment of early‐stage cancers which could strongly improve therapies efficiency. Despite these remarkable attainments, micromachines, to actually become revolutionary, require a tracking system at least as accurate as its size and working in an heterogeneous environment. The aim of the present paper was to provide an overview of the state of the art in medical device tracking systems for the brain. Firstly, the latest advances are categorized by technological family: magnetic field, electromagnetic waves, magnetic resonance, ultrasound waves and hybrid solutions. Secondly, in a comparative purpose, performance criteria are evaluated and displayed in radar diagrams and graphs to highlight the three dimensions challenge the systems should take up: performance, invasiveness and user experience. Finally, the present and future of each localization family are provided.

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“…Other techniques, such as MRI, are generally too slow to detect these changes with a sufficient spatial resolution. Recent work has combined ultrafast plane-wave and tomographic techniques, leading to '4D' measurements in a rat brain, with a resolution of 100 μm × 100 μm × 100 μm and 10 ms (Demené et al 2016).…”

Section: Doppler Methodsmentioning

confidence: 99%