Oliver C. Kiersnowski1, Gavin P. Winston2,3, Emma Biondetti1,4, Sarah Buck2, Lorenzo Caciagli2,5, John Duncan2, Karin Shmueli1, and Sjoerd B. Vos6,7
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Department for Clinical and Experimental Epilepsy, University College London, London, United Kingdom, 3Department of Medicine, Division of Neurology, Queen's University, Kingston, ON, Canada, 4Institut du Cerveau – ICM, INSERM U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France, 5Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 6Centre for Medical Image Computing, Computer Science Department, University College London, London, United Kingdom, 7Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2Department for Clinical and Experimental Epilepsy, University College London, London, United Kingdom, 3Department of Medicine, Division of Neurology, Queen's University, Kingston, ON, Canada, 4Institut du Cerveau – ICM, INSERM U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France, 5Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 6Centre for Medical Image Computing, Computer Science Department, University College London, London, United Kingdom, 7Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
Magnetic susceptibility values
differ significantly between 23 healthy controls and 31 people with temporal
lobe epilepsy (TLE) in the thalamus, putamen, and globus pallidus. Hippocampal
susceptibility values are asymmetric in TLE patients, with lower values in the affected
hippocampus.
Figure 1:
Example T1-weighted image (left) with ROIs superimposed (caudate: R=yellow,
L=dark blue; putamen: R=red; L=dark green; globus pallidus: R=pink, L=light
blue; thalamus: R=light green, L=brown), first and final echo gradient echo
(GE) magnitude image, and susceptibility map calculated using iterative
Tikhonov regularisation and weak harmonic (WH) QSM for a representative control
subject. WH QSM was used here as its reduced noise and residual background
fields yielded significant $$$\chi$$$ differences unlike
the iterative Tikhonov technique.
Figure 2: Box plots of deep gray matter regions with significant group differences in age-corrected mean susceptibility. HC=healthy controls, LTLE=left temporal lobe epilepsy, RTLE=right temporal lobe epilepsy. * indicates p<0.05, ** indicates p<0.01, *** indicates p<0.001.