Monday, 24 April 2017

Longitudinal whole-brain atrophy and ventricular enlargement in nondemented Parkinson's disease

Great example of how MRI can to used to supplement clinical trials in PD... I think it very helpful that the authors included the estimation of how use of an imaging biomarker could reduce a required sample size to 1/15th especially at a time when we are adding to our armoury of options for use in clinical trials of disease modifying therapy... MRI is widely available and reasonable in terms of cost too...

Neurobiol Aging. 2017 Mar 16;55:78-90. doi: 10.1016/j.neurobiolaging.2017.03.012. [Epub ahead of print]
Mak E, Su L, Williams GB, Firbank MJ, Lawson RA, Yarnall AJ, Duncan GW, Mollenhauer B, Owen AM, Khoo TK, Brooks DJ, Rowe JB, Barker RA, Burn DJ, O'Brien JT.

http://www.neurobiologyofaging.org/article/S0197-4580(17)30083-0/abstract

We investigated whole-brain atrophy and ventricular enlargement over 18 months in nondemented Parkinson's disease (PD) and examined their associations with clinical measures and baseline CSF markers. PD subjects (n = 100) were classified at baseline into those with mild cognitive impairment (MCI; PD-MCI, n = 36) and no cognitive impairment (PD-NC, n = 64). Percentage of whole-brain volume change (PBVC) and ventricular expansion over 18 months were assessed with FSL-SIENA and ventricular enlargement (VIENA) respectively. PD-MCI showed increased global atrophy (-1.1% ± 0.8%) and ventricular enlargement (6.9 % ± 5.2%) compared with both PD-NC (PBVC: -0.4 ± 0.5, p < 0.01; VIENA: 2.1% ± 4.3%, p < 0.01) and healthy controls. In a subset of 35 PD subjects, CSF levels of tau, and Aβ42/Aβ40 ratio were correlated with PBVC and ventricular enlargement respectively. The sample size required to demonstrate a 20% reduction in PBVC and VIENA was approximately 1/15th of that required to detect equivalent changes in cognitive decline. These findings suggest that longitudinal MRI measurements have potential to serve as surrogate markers to complement clinical assessments for future disease-modifying trials in PD.

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