No abstract

MR imaging planimetry measurements are potent imaging markers of progressive supranuclear palsy and promising markers of corticobasal degeneration but do not seem to assist in the diagnosis of multiple system atrophy with parkinsonism.

The phenotypic heterogeneity in amyotrophic lateral sclerosis (ALS) implies that patients show structural changes within but also beyond the motor cortex and corticospinal tract and furthermore outside the frontal lobes, even if frank dementia is not detected. The aim of the present study was to investigate both gray matter (GM) and white matter (WM) changes in non-demented amyotrophic lateral sclerosis (ALS) patients with or without cognitive impairment (ALS-motor and ALS-plus, respectively). Nineteen ALS-motor, 31 ALS-plus and 25 healthy controls (HC) underwent 3D-T1-weighted and 30-directional diffusion-weighted imaging on a 3 T MRI scanner. Voxel-based morphometry and tract-based spatial-statistics analysis were performed to examine GM volume (GMV) changes and WM differences in fractional anisotropy (FA), axial and radial diffusivity (AD, RD, respectively). Compared to HC, ALS-motor patients showed decreased GMV in frontal and cerebellar areas and increased GMV in right supplementary motor area, while ALS-plus patients showed diffuse GMV reduction in primary motor cortex bilaterally, frontotemporal areas, cerebellum and basal ganglia. ALS-motor patients had increased GMV in left precuneus compared to ALS-plus patients. We also found decreased FA and increased RD in the corticospinal tract bilaterally, the corpus callosum and extra-motor tracts in ALS-motor patients, and decreased FA and increased AD and RD in motor and several WM tracts in ALS-plus patients, compared to HC. Multimodal neuroimaging confirms motor and extra-motor GM and WM abnormalities in non-demented cognitively-impaired ALS patients (ALS-plus) and identifies early extra-motor brain pathology in ALS patients without cognitive impairment (ALS-motor).

No abstract

No abstract

PLC in ALS is driven by both GM and WM abnormalities which highlight the role of circuits rather than isolated centers in the emergence of this condition. ALS is suggested as a useful natural experimental model to study PLC.

No abstract

Introduction Various MRI markers have been applied to support the diagnosis of progressive supranuclear palsy (PSP), such as midbrain diameter and surface, superior cerebellar peduncle (SCP) width, midbrain to pons (m/p) diameter and surface ratio and the Magnetic Resonance Parkinsonism Index (MRPI). These markers provide excellent diagnostic accuracy in discriminating Richardson's syndrome from other causes of Parkinsonism. Idiopathic normal pressure hydrocephalus (iNPH) may mimic Richardson's syndrome, particularly in cases of subtle opthalmokinetic abnormalities. The aim of this study was to compare these MRI markers in PSP and iNPH and examine their diagnostic accuracy. Materials and Methods Forty‐three patients with probable PSP, 17 patients with iNPH, and 29 controls were included. Midbrain diameter and surface, SCP width, m/p diameter and surface ratio and the MRPI were recorded. The “hummingbird sign,” “morning glory sign” and “mickey mouse sign” were also evaluated. Analysis of covariance, chi‐squared test, and ROC curve analysis were used as appropriate. Results All MRI measurements differed significantly among the three study groups. Comparison of PSP and iNPH patients produced the following significant differences: midbrain diameter (P < .0001), m/p diameter ratio (P < .0001), SCP width (P = .050), and MRPI (P = .049). None of these markers produced combined high (>80%) specificity and sensitivity. Qualitative MRI signs were specific, but lacked sensitivity. Discussion Midbrain morphology in iNPH may resemble that of PSP. Established MRI markers of midbrain and SCP atrophy cannot confidently differentiate PSP from iNPH. MRI markers do not provide combined high sensitivity and specificity for the differential diagnosis of PSP from iNPH.