What is functional ultrasound imaging ?
Functional ultrasound imaging is a high-sensitivity high-spatial and high-temporal resolution imaging modality of the brain activity and cerebro-vascular flows. Functional ultrasound imaging allows mapping very small variations of cerebral blood volume thanks to dedicated ultra-high sensitivity sequences and optimized hardware. This revolutionary technology is based on ultra high sensitivity ultrasound imaging using multi-plane wave transmissions at thousands of frames per second.
Functional ultrasound imaging offers a large range of applications including :
Mapping blood vessels and their blood volume variations at high sensitivity and spatio-temporal resolution
Task-based functional imaging (such as in fMRI)
Pharmacalogy-induced blood volumes variations (such as in PhMRI)
Unsupervised functional imaging for awake animals
Functional Connectivity matrix assessment (such as in resting state rsMRI)
What is the difference with xyz ultrasound machine ?
Unlike conventional ultrasound imaging, functional ultrasound imaging relies on multi-plane wave transmissions at thousands of frames per second. Your department or company may have already access or plan to purchase an ultrasound machine. However, those machines cannot be used or upgraded to be used for functional ultrasound imaging.
Iconeus platform relies on a unique patented technology.
Our dedicated hardware and software allows acquiring and processing huge amount of data which provides our unique ultra-high sensitivity.
Do not hesitate to look at and share blood vessels images to fully appreciate the technology gap with conventional ultrasound machines that you can find in the market.
What is the story of functional brain ultrasound and Iconeus ?
Functional ultrasound imaging is based on ultra high sensitivity Doppler imaging based on plane wave acquisitions that was pionneered by the Langevin Institute (ESPCI/CNRS/INSERM), Paris, France. Very high frame rate imaging improves drastically Doppler imaging sensitivity and led to a breakthrough neurofunctional imaging modality (Nature Methods, 2011). Since then,
continuous innovations leveraged the technology from the physics bench to a high-end, plug&play technology for neuroscientists.
For more details on functional imaging please visit the websites of our academic scientific partner:
What is measured by functional ultrasound imaging ?
Functional ultrasound imaging uses ultra-high sensitivity Power Doppler sequences to estimate the blood volume in small vessels.
It has been shown that Power Doppler is proportional to the Cerebral Blood Volume (CBV).
Thanks to this direct link with CBV, functional ultrasound imaging can measure cerebral activity with CBV increases between 10% to 50% during stimulations, a variation much larger that what can be measured with the Bold effect in fMRI.
What is the spatiotemporal resolution of functional ultrasound imaging ?
Our system uses a high frequency transducer at 15MHz that provides in plane spatial resolution of 100µm with a 400 µm slice width .
The temporal resolution of the raw ultrasound images is around 50 microseconds.
The temporal resolution of the Cerebral Blood Volume images is between 50 milliseconds and 1 second and can be adapted depending on the study, physiology and required sensitivity.
In rodents, fUS imaging of brain activity typically has a 100×100 micrometer in-plane spatial resolution and one cardiac cycle (200 milliseconds temporal resolution in mice, 300 milliseconds in rats).
What is the sensivity of functional ultrasound imaging ?
Iconeus technologies allow to reach a sensitivity hundred times higher than conventional preclinical ultrasound systems that can be found in the market.
Iconeus ultra-high sensitivity to cerebral blood volume is the true engine that allows functional ultrasound imaging with deep penetration capabilities leading to whole brain imaging.
How long does take one aquisition ?
The duration of an acquisition ranges from several seconds to several hours depending on the physiological phenomenon that is being observed.
Typically, task-based functional ultrasound imaging requires between 30 seconds to 5 minutes depending on the stimulus pattern used.
Connectivity matrix construction requires between 5 to 10 minutes in anesthesized specimens and between 10 to 30 minutes in awake specimens.
Acquisition duration can go up to dozen of hours, where the internal hard drive is the only limit. If you need a specific configuration for your setup, please do not hesitate to contact an Iconeus representative. Our versatile technology offers many possibilities.