Contributions
Abstract: P1076
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Purpose: Determine age-dependent annual whole brain (WB) and grey matter (GM) volume changes in healthy controls using MSmetrix.
Materials and methods: Magnetic resonance images (MRIs) from healthy controls were considered from several (mainly publically available) sources. A first collection (cross-sectional database), consisted of 1281 subjects aged 18 to 85. A second collection (longitudinal database), consisted of 300 subjects aged 18 to 80, for which at least two MRI sessions >4 months apart were available.
On both datasets, MSmetrix computed WB and GM volumes normalized for head size, using T1-weighted MRI, while for the longitudinal data, percentage volume change was computed using two T1-weighted images simultaneously.
Spline fitting was applied to volumes from the cross-sectional dataset to obtain age-dependent median WB and GM volume curves. Age-dependent normal atrophy rates were then estimated as the local derivative of the median curves.
The longitudinal-computed annualised atrophy values from all paired sessions in the longitudinal dataset were then compared against age-matched normal atrophy rates obtained from the cross-sectional dataset. Statistical hypothesis testing (t-test and Wilcoxon signed rank test) was used to indicate whether there is any bias from zero in the mean value of the differences between these two measurements.
Results: From the cross-sectional dataset, the age-dependent normal atrophy rates for WB varied from -0.03% around 25y old to -0.28% around 75y old (in line with previously reported values [1]), while normal atrophy rates for GM varied from -0.28% around 25y old to -0.21% around 75y old. Statistical testing showed that the MSmetrix volume changes in the longitudinal dataset were unbiased compared to the age-matched normal atrophy rates (null hypothesis that the mean is different from zero was rejected at significance level 0.1).
Conclusion: MSmetrix age-dependent normal annual atrophy rates in healthy controls serve as a robust reference to better assess severity of brain atrophy in MS patients.
References: [1] De Stefano N, Stromillo ML, Giorgio A, et al. Establishing pathological cut-offs of brain atrophy rates in multiple sclerosis. J Neurol Neurosurg Psychiatry Published Online First: 22 April 2015. doi: 10.1136/jnnp-2014-309903
Disclosure: All authors are employed by icometrix.
Acknowledgements: The data used has been partly supported by CENTER-TBI (FP7-COOPERATION-2013-602150)
Abstract: P1076
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Purpose: Determine age-dependent annual whole brain (WB) and grey matter (GM) volume changes in healthy controls using MSmetrix.
Materials and methods: Magnetic resonance images (MRIs) from healthy controls were considered from several (mainly publically available) sources. A first collection (cross-sectional database), consisted of 1281 subjects aged 18 to 85. A second collection (longitudinal database), consisted of 300 subjects aged 18 to 80, for which at least two MRI sessions >4 months apart were available.
On both datasets, MSmetrix computed WB and GM volumes normalized for head size, using T1-weighted MRI, while for the longitudinal data, percentage volume change was computed using two T1-weighted images simultaneously.
Spline fitting was applied to volumes from the cross-sectional dataset to obtain age-dependent median WB and GM volume curves. Age-dependent normal atrophy rates were then estimated as the local derivative of the median curves.
The longitudinal-computed annualised atrophy values from all paired sessions in the longitudinal dataset were then compared against age-matched normal atrophy rates obtained from the cross-sectional dataset. Statistical hypothesis testing (t-test and Wilcoxon signed rank test) was used to indicate whether there is any bias from zero in the mean value of the differences between these two measurements.
Results: From the cross-sectional dataset, the age-dependent normal atrophy rates for WB varied from -0.03% around 25y old to -0.28% around 75y old (in line with previously reported values [1]), while normal atrophy rates for GM varied from -0.28% around 25y old to -0.21% around 75y old. Statistical testing showed that the MSmetrix volume changes in the longitudinal dataset were unbiased compared to the age-matched normal atrophy rates (null hypothesis that the mean is different from zero was rejected at significance level 0.1).
Conclusion: MSmetrix age-dependent normal annual atrophy rates in healthy controls serve as a robust reference to better assess severity of brain atrophy in MS patients.
References: [1] De Stefano N, Stromillo ML, Giorgio A, et al. Establishing pathological cut-offs of brain atrophy rates in multiple sclerosis. J Neurol Neurosurg Psychiatry Published Online First: 22 April 2015. doi: 10.1136/jnnp-2014-309903
Disclosure: All authors are employed by icometrix.
Acknowledgements: The data used has been partly supported by CENTER-TBI (FP7-COOPERATION-2013-602150)