IC‐P2‐095: Rates of whole brain atrophy and ventricular enlargement: Correlations with cognitive performance

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Whole-brain and ventricular change using serial MR has been shown to be useful in assessing putative treatments in Alzheimer's disease (AD). We aimed to correlate change in whole brain and ventricular volume with cognitive scores in AD, MCI and control subjects. Eighty-seven controls, 118 mild cognitive impairment (MCI) and 48 AD subjects were selected from the Alzheimer's disease neuroimaging initiative (ADNI) cohort. Each subject underwent a volumetric T1-weighted MRI at baseline and 12 months. Whole brain was segmented on baseline scans with a semi-automated technique. Repeat brain regions were propagated from the baseline regions. Baseline and repeat scans were registered using a 9-degrees of freedom algorithm. Ventricles were segmented at both time points, also using a semi-automated technique. Brain and ventricular changes were measured using the Boundary Shift Integral (BBSI and VBSI respectively). The MMSE was also completed by every participant at both time points. Whole-brain loss was significantly different between controls, MCI and AD (p<0.001); pair-wise comparisons showed the BBSI was lower in controls than in AD (p<0.001) and MCI (p=0.022); the AD group had a trend towards a higher brain atrophy rate than MCI (p=0.052). Ventricular enlargement was different between the three groups (p<0.001), with AD>MCI (p<0.001), AD>control (p<0.001) and MCI>control (p<0.001). Change in MMSE was also different between controls, MCI and AD (p<0.001), with AD>MCI (p=0.009) and AD>controls (p<0.001) (table). In both MCI and AD groups change in MMSE was associated with BBSI (MCI p<0.001, AD p=0.003) and VBSI (MCI p<0.001, AD p=0.001). Finally, the MCI group was divided into two groups: those with MMSE change<1, and MMSE change>or equal to 1. There was no significant interaction between BBSI and MMSE change in the MCI divisions (p>0.05), but there was a significant interaction between MMSE change and VBSI and MCI divisions (p<0.01), (Figure). Whole-brain atrophy rates and ventricular enlargement increased across subject groups with control<MCI<AD. This was also reflected in neuropsychology, with MMSE change increasing across groups control<MCI<AD. Some association was found between MMSE (change) and brain atrophy and ventricular enlargement in AD and MCI.

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