Morphometry
Altered size and shape of brain structures can be observed in association with disease. These abnormalities can be detected using various structural MRI methods including voxel based morphometry and cortical thickness analysis of T1-weighted MRI scans.
There is increasing realisation that large multi-centre datasets can be a powerful means to reveal subtle abnormalities in brain structure associated with particular diseases. We therefore developed and validated methods for multi-site voxel based morphometry to allow scans from different labs and scanners to be analysed together.
In our investigations of cortical thickness, we have discovered that it is not just the cortical thickness value in a region that can reveal abnormality. We searched for differences in cortical thickness covariance – specifically, correlations of the cortical thicknesses of pairs of brain regions across individuals – in patients with Childhood Absence Epilepsy. We found significant differences compared to healthy controls, even though the absolute cortical thickness of any particular region was not significantly different between patients and controls. We hypothesise that we are detecting changes in the way brain regions grow together, influenced perhaps by genetic or other developmental factors, or possibly by epileptiform activity.
Selected publications
Curwood EK, Pedersen M, Carney PW, Berg AT, Abbott DF† & Jackson GD† (†=joint senior authors). Abnormal cortical thickness connectivity persists in Childhood Absence Epilepsy. Annals of Clinical and Translational Neurology 2(5) 456–464 (2015) ( doi: 10.1002/acn3.178 ).
Pardoe HR, Abbott DF, Jackson GD. Sample size estimates for well-powered cross-sectional cortical thickness studies. Human Brain Mapping 34(11):3000-9 (2013) ( doi:10.1002/hbm.22120 ).
Morrell MJ, Jackson ML, Twigg GL, Ghiassi R, McRobbie DW, Quest RA, Pardoe H, Pell GS, Abbott DF, Rochford PD, Jackson GD, Pierce RJ, ODonoghue FJ, Corfield DR. Changes in brain morphology in patients with obstructive sleep apnoea. Thorax 65(10)908-914. (2010)
Pardoe HR, Pell GS, Abbott DF, Jackson GD. Hippocampal volume assessment in temporal lobe epilepsy: How good is automated segmentation? Epilepsia 50(12):2586-2592 (2009).
Pardoe HR, Pell GS, Abbott DF, Berg AT and Jackson GD. Multi-site voxel-based morphometry: Methods and a feasibility demonstration with childhood absence epilepsy. NeuroImage 42(2):611-616 (2008).
Pell GS, Briellmann RS, Chan CHP, Pardoe H, Abbott DF, Jackson GD. Selection of the control group for VBM analysis: Influence of covariates, matching and sample size. NeuroImage 41(4):1324-1335 (2008).
Pell GS, Briellmann RS, Pardoe HR, Abbott DF, and Jackson GD. Composite voxel-based analysis of volume and T2 relaxometry in temporal lobe epilepsy. NeuroImage 39(3): 1151-1161 (2008).
O'Donoghue FJ, Briellmann RS, Rochford PD, Abbott DF, Pell GS, Chan CH, Tarquinio N, Jackson GD, Pierce RJ. Cerebral Structural Changes in Severe Obstructive Sleep Apnea. Am J Respir Crit Care Med 171(10):1185-1190 (2005).
