Atypical Cognitive Disorders Clinical Trial
Official title:
Study of MRI 3 Tesla Using Arterial Spin Labeling (Without Infusion) in Cognitive Atypical Disorders and Comparison to FDG-PET
DESCRIPTION OF RELATED QUESTION Cognitive disorders are frequently encountered and present a
major public health problem given the aging of the population.
There is not one, but several neurodegenerative pathologies individual differentiated.
Particularly distinguished is Alzheimer's disease (the most common), dementia lobar
fronto-temporal associated with semantic dementia (a disease with a particular tropism for
semantic memory and the anterior temporal lobe), and dementia with Lewy bodies.
To differentiate these pathologies is, for the clinician, is a major issue and the clinic may
not be enough.
The management and current diagnostics of atypical cognitive disorders, that is to say,
patients with clinical symptoms or neuropsychological testing results suggestive of a
neurodegenerative disorder other than Alzheimer's disease, are based largely on data imaging.
In the first intention, conducting imaging by MRI is recommended by the HAS, particularly to
search for treatable causes to these cognitive disorders (tumors, intracranial hemorrhage in
particular) but also to study the distribution of cerebral atrophy.
The sequences used are the sequences 3D T1, axial Flair, gradient echo axial T2 and coronal
T2 in the plane of hippocampi and also diffusion imaging.
Research has shown interest in the study of cerebral perfusion in cognitive disorders.
The HAS recommends not to inject contrast medium on MRI in this context. The sequence of
perfusion by tagging arterial protons or "arterial spin labeling" (ASL) does not use
exogenous contrast medium. This is available as a commercial product, CE marked, on most of
the recent clinical MRI scanners. This non-invasive technique, requiring no special
precautions (e.g. verification of renal function) is used in routine clinical practice at the
University Hospital of Rennes and in many centers. In the imaging of patients with dementia,
it is widely used as well as the 3D T1 sequences or diffusion imaging (International
Initiative ADNI) and is subject to optimization and harmonization of use in routine clinical
practice with the European COST AID actions.
The second intention, an isotope imaging by FDG-PET or study of perfusion SPECT can also be
performed. The interest of isotopic imaging (FDG-PET and SPECT) lies in the provision of
information metabolic nonexistent in MRI, with a superiority of FDG-PET compared with SPECT.
FDG-PET is the preferred examination and is carried out at CRLCC Eugène Marquis de Rennes in
this context.
The aim of our study is to compare the imaging of TEPFDG, a technique not morphological, and
ASL that, even if they do not study the same mode (metabolism for the first and perfusion for
the second) may depict consistent anomalies.
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