[Neuroimaging in dementia].
Imaging is a part of the work-up for all types of dementia. X-ray computed tomography (CT) is a first-line examination to rule out causes of surgical, and thus reversible, dementia (for example, subdural hematoma or normal pressure hydrocephalus). MRI (magnetic resonance imaging) is preferred for work-ups of dementia. In the neurodegenerative dementias, the topography of the atrophy provides information about the specific type: atrophy of the medial temporal lobe is predominant in Alzheimer disease, while atrophy of the frontal and anterior temporal lobes is seen in frontotemporal dementia, with less medial temporal atrophy than in Alzheimer disease for frontotemporal dementia; vascular dementia is marked by infarction, lacuna, and signal abnormalities in the white matter and sometimes microbleeding. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are used in clinically atypical forms. Study of the dopamine transporter (DATscan) is used to distinguish Lewy body dementia from Alzheimer disease. Numerous studies are underway to identifying specific imaging markers for different types of dementia, including cerebral volumetric measurements, diffusion imaging, spectroscopy, very-high-field MRI scans of senile plaques, and PET markers of senile plaques.
Lehéricy
Stéphane
S
Inserm U610, Service de neuroradiologie et Centre de NeuroImagerie de Recherche, Centre hospitalo-universitaire Pitié-Salpêtrière, Paris (75). stephane.lehericy@psl.aphp.fr
Delmaire
Christine
C
Galanaud
Damien
D
Dormont
Didier
D
D000544:Alzheimer Disease / Q000175:diagnosis / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D003704:Dementia / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015140:Dementia, Vascular / Q000175:diagnosis / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D020734:Parkinsonian Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D013057:Spectrum Analysis; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*