Biomedical Engineering Reference
In-Depth Information
from the latest developments in the domain of ultra high fields and from the latest
image processing innovations in the field of diffusion imaging based on high angular
resolution models. Determining the biomarkers for the various forms of Parkinson's
disease using high field systems will surely open the way for developing new
diagnosis tools at lower field strengths and thus make them available to a clinical
environment. Deep brain nuclei are important structures that are involved in a
large array of behaviors, such as locomotion, eye-movement, or sleep. Damage
to these structures leads to movement disorders such as Parkinson's disease. To
date, except for the larger striato-pallidal complex, there are no reliable imaging
markers of small deep nuclei. With dMRI and refinements of neuroimaging methods
and higher field magnets, imaging of these nuclei has become possible. Together
with our collaborators at the Center of Neuroimaging Research (CENIR, Paris,
France) and CEA Neurospin (Saclay, France), we are currently conducting a series
of experiments in normal volunteers and in patients with basal ganglia pathology
to characterize deep brain structures and study the structural disorders of the
brainstem in the case of Parkinsonian syndromes. More precisely, we are involved
in the data analysis part with the objective to detect the anatomical connectivity
of the brainstem structures and their connectivity to the brain and we hope to
find new neuroimaging markers of deep brain nuclei that could be used for the
diagnosis of Parkinsonian syndromes at an early stage. Possible extension and
improvements of the tractography algorithms presented here would be necessary
to obtain a satisfactory spatial resolution for identifying the anatomical network
involved in Parkinson's disease and improve the characterization of lesions of deep
brain structures.
An important application where dMRI is expected to significantly impact in the
close future is Traumatic Brain Injury (TBI), which is the damage caused to the brain
due to external mechanical force, such as rapid acceleration or deceleration, falls,
motor vehicle accidents, impact or penetration by a projectile. The worst injuries
can lead to permanent brain damage or death. Because a sudden and violent trauma
to the head can cause injury to and shearing of the white matter fibers, it's indeed
possible to use dMRI to examine the integrity of white matter that is especially
vulnerable to TBI. This opens the way to exciting and challenging problems to
quantify and qualify structural changes in white matter.
To this date, a large number of dMRI clinical studies of TBI only uses simple
scalar diffusion measurements such as FA and/or MD to characterize the structural
abnormalities present along a given fiber pathway to identify pathologies and
compare patients with healthy controls. This clearly opens the road to many exciting
and challenging problems to examine with more elaborate diffusion models the
white matter's integrity and to better quantify and qualify structural changes in white
matter.
Through our collaborations with clinical partners and our development of
innovative tensor and HARDI processing methods, we are convinced that we can
advance further our ability to better understand the architecture of the CNS and help
to prove that dMRI can provide a relevant source of useful information, such as in
vivo markers of diseases in clinical neuroscience.
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