Article

Conventional MRI is a well-described, highly useful tool for the differential
diagnosis of degenerative parkinsonian syndromes. Nevertheless, the observed
abnormalities may only appear in late-stage disease. Diffusion tensor imaging
(DTI) can identify microstructural changes in brain tissue integrity and
connectivity. The technique has proven value in the differential diagnosis of
multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and
Parkinson's disease (PD). Here, we performed a systematic review of the
literature on the main corticosubcortical DTI abnormalities identified to date in
the context of the diagnosis of MSA and PSP with diffusion-weighted imaging,
diffusion tensor imaging and anatomical connectivity studies. In good agreement
with the histological data, increased diffusivity in the putamen (in MSA and
PSP), in the middle cerebellar peduncles (in MSA) and in the upper cerebellar
peduncles (in PSP) has been reported. Motor pathway involvement is characterized
by low fraction anisotropy (FA) in the primary motor cortex in MSA-P and PSP, a
high apparent diffusion coefficient (ADC) and low FA in the supplementary motor
area in PSP. We then outline the value of these techniques in differential
diagnosis (especially with respect to PD). Anatomical connectivity studies have
revealed a lower number of fibers in the corticospinal tract in MSA and PSP
(relative to PD and controls) and fewer tracked cortical projection fibers in
patients with PSP or late-stage MSA (relative to patients with early MSA or PD
and controls). Lastly, we report the main literature data concerning the value of
DTI parameters in monitoring disease progression. The observed correlations
between DTI parameters on one hand and clinical scores and/or disease duration on
the other constitute strong evidence of the value of DTI in monitoring disease
progression. In MSA, the ataxia score was correlated with ADC values in the pons
and the upper cerebellar peduncles, whereas both the motor score and the disease
duration were correlated with putaminal ADC values. In conclusion, DTI and
connectivity studies constitute promising tools for differentiating between
"Parkinson-plus" syndromes.
CI - Copyright (c) 2014 Elsevier Masson SAS. All rights reserved.

Langue : ANGLAIS