Bruno Law-Ye JD, Presenter: Nothing to Disclose

Daniel Garcia-Lorenzo, Abstract Co-Author: Nothing to Disclose

Romain Valabregue, Abstract Co-Author: Nothing to Disclose

Lydia Yahia-Cherif, Abstract Co-Author: Nothing to Disclose

Marie Vidailhet, Abstract Co-Author: Nothing to Disclose

Stephane Lehericy MD, PhD, Abstract Co-Author: Nothing to Disclose

Cognitive disorders are among the most frequent non-motor symptoms of Parkinson's disease, including attentional and executive disorders but also memory disorders. Our goals were to assess the structural impairment of hippocampus in Parkinson's disease (PD), by means of voxel-based morphometry and diffusion tensor imaging (DTI) in 3 Tesla MRI and determine its relation to mild cognitive impairment (MCI) in PD.

Our population consisted of 55 parkinsonian patients (PD) and 25 healthy volunteers (HV), included prospectively between 2010 and 2012. Diagnosis of idiopathic Parkinson disease had been assessed by neurologists. All patients were tested by a neuropsychologist. PD patients were divided into patients with mild cognitive impairment (MCI, n = 23) and patients without MCI (non MCI, n = 32). All patients underwent brain MRI (3 Tesla, Trio TIM 32 channels, Siemens) including 3DT1 MP-RAGE, 3D T2* and diffusion tensor imaging. Hippocampus were segmented automatically by Freesurfer® software, needing manual corrections in 6 patients (7,5%). Pre-treatments of the T1 and DTI images were performed using FSL® non-linear image registration tool. Then voxel-based-morphometry and DTI analysis provided us the data for hippocampal volumes, fractional anisotropy (FA) and mean diffusivity (MD)

Hippocampal MD was significantly increased in PD patients vs HV (0.8496 vs 0.8217 mm²/s; p= 0.01). MD was significantly increased in MCI PD patients when compared with non-MCI PD patients (0.8564 vs 0.8450 mm²/s ; p=0.03). We did not find a significant difference of hippocampal volume in PD vs HV. There was however a trend toward volume decrease in MCI vs non-MCI patients (4057,2 vs 4214,1 cubic millimeters; p= 0.11) There was no significant modification of FA in PD vs HV or MCI vs non-MCI.

Hippocampal MD was significantly increased in PD patients compared with healthy volunteers, underlining the specific impairment of this structure in Parkinson's disease. MD was significantly increased in the MCI vs the non-MCI PD. Based on our results, hippocampal MD might be a specific and reliable biomarker in Parkinson's disease cognitive troubles.

Diffusion tensor imaging can demonstrate the structural impairment of hippocampus in Parkinson's disease (PD) and its correlation to the specific cognitive disorders of PD.

Law-Ye, B, Garcia-Lorenzo, D, Valabregue, R, Yahia-Cherif, L, Vidailhet, M, Lehericy, S, Correlating the Structural Impairment of Hippocampus with Cognitive Disorders in Parkinson's Disease: a 3T MRI Voxel-based Morphometry and Diffusion Tensor Imaging Study on 80 Patients.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14005543.html