Détails de la réservation
- Le : 26 January 2018
- De : 11 h 30
- à : 12 h 30
- Salle : Amphi Centre Broca Nouvelle - Aquitaine
Détails de l'évènement
Mickael Tanter
Research Professor of the French National Institute for Health and Medical Research, Institut Langevin,
ESPCI, Paris France
"Functional Ultrasound Imaging of Neuronal Activity"
Résumé
Functional imaging modalities such as fMRI or optical imaging identify regions of brain activity by measuring changes in blood flow thanks to the neurovascular coupling. Paradoxically, Ultrasound was not present in the field of Neuroscience till recently, whereas it is the most used modality for blood flow imaging in clinics. The reason for this was the poor sensitivity of Doppler ultrasound limiting blood flow imaging to large arteries. Ultrafast Doppler imaging based on plane wave imaging breaks this barrier and enabled recently the emergence of fUltrasound (by analogy to fMRI). fUltrasound (fUS) is able to provide unique whole brain images of perfusion on small rodents with unprecedented resolutions (100 µm and 10 ms). Functional imaging of cerebral blood volume during epileptic seizures, whisker or odor stimulations, drug injection emphasizes the potential of this new imaging modality to provide completely new information for the understanding of brain. As fUltrasound relies on ultrafast ultrasound acquisitions, it also enables the whole brain mapping of vascular indexes (such as resistivity, pulsatility or transient systolic time indexes) within a single cardiac cycle in addition to functional imaging of brain activity on longer time scales.
fUS is a great tool for neuroimaging on small animals as it already helps both to answer unsolved questions and image the functional activity of to date unexplored brain regions. It should become a a full-fledged imaging modality of neuroscience as it provides the first whole brain and portable neuroimaging modality for awake and freely moving animal studies. Beyond small animal imaging, clinical fUS should become an alternative to fMRI in particular applications, such as newborns or preterm infants both for neonatal seizure monitoring or cognitive science studies. It could also become a powerful portable tool for neuroimaging during peroperative surgery on adults.
Finally, we demonstrated recently that it can be combined with 3 µm diameter microbubbles injections in order to provide a first in vivo and non-invasive imaging modality at microscopic scales deep into organs (figure 2) combined with contrast agents by localizing the position of millions of microbubbles at ultrafast frame rates. This ultrasound localization microscopy technique solves for the first time the problem of in vivo imaging at microscopic scale the whole brain vasculature. Beyond fundamental neuroscience or stroke diagnosis, it will certainly provide new insights in the understanding of tumor angiogenesis.
Responsable
- Nom : Nathalie Tzourio-Mazoyer