Email: david.rudko [at] mcgill.ca
Academic affiliations: Neurology and Neurosurgery, Biomedical Engineering, Director of 7 T Pre-Clinical MRI Unit
Research group: Neuroimaging and Neuroinformatics
“I’m studying how brain tissue structure changes in neurological diseases,” explains Rudko. “In terms of clinical work, my lab examines demyelinating disorders such as multiple sclerosis."
Research in our lab is focused on the application of novel MRI methodology in conjunction with biophysical modeling to augment the current understanding of brain anatomy and physiology. In neurological disease, the interplay between sub-voxel, cellular-level components such as microglia and axons executes a critical role in determining disease onset and progression. To investigate these features, our lab utilizes both small animal (7 T) and human MRI/MRS (3 T, 7 T) in conjunction with optical microscopy and advanced image processing methods. In particular, we develop MRI physics acquisition and post-processing techniques for mapping myelin density, axonal packing and axonal geometry. To improve existing models, we use numerical, magnetostatic/tissue relaxation simulation models based on the cell-level geometries observed from human brain histology images. An ultimate goal is to extend magnetic susceptibility and relaxometry-based MRI models of brain tissue microstructure to develop atlases applicable to neurological disease.
Equally relevant, our lab also focuses on the advancement of physics, signal processing and hardware methodology for ultra-high field (UHF, > 3T) MRI. The current breadth of application of UHF MRI to neurological diseases represents only the tip of the iceberg. The challenge moving forward will be to leverage advanced MRI physics techniques, primarily developed at 3 T, for use with 7 T MRI. This requires addressing several critical challenges associated with UHF MRI. First, the decreased radiofrequency (RF) field wavelength associated with UHF MRI requires consistent mapping of the transmit RF field (B1+). Secondly, UHF MRI is associated with increased static magnetic field inhomogeneities (B0 effects). A consequent motivation in our lab is to advance techniques related to (a) RF field homogenization (static and dynamic B1+ shimming methods) and (b) B0 shimming (B0 field mapping, gradient Z-shimming and multi-coil shim arrays).
1. Hosseini Z., Matusinec J.A., Rudko D.A., Liu J., Kwan B.Y.M., Salehi F., Sharma M., Kremenchutzky M., Menon R.S., Drangova M. "Morphology-Specific Discrimination Between MS White Matter Lesions and Benign White Matter Hyperintensities Using Ultra-High Field MRI," American Journal of Neuroradiology. Accepted, May 2018.
2. Akbar N.A., Rudko D.A., Parmar K. "Magnetic resonance imaging of multiple sclerosis," Scientific Journal of Multiple Sclerosis. November 2017; 1(1):008-020.
3. Maranzano J., Rudko D.A., Arnold D.L., Narayanan S. "MRI evidence of acute inflammation in leukocortical lesions of early multiple sclerosis patients," Neurology. August 2017; 89(7):714-721.
4. Bernhardt B.C., Fadaie F., Vos de Wael R., Hong S.J., Liu M., Guiot M.C., Rudko D.A., Bernasconi A., Bernasconi N. "Preferential susceptibility of limbic cortices to microstructural damage in temporal lobe epilepsy: A quantitative T1 mapping study," NeuroImage. June 2017; S1053-8119(17): 30471-8.
5. Streijger F., Lee J.H.T., Manouchehri N., Anderson L., Okon E.B., Tigchelaar S., Anderson L.M., Dekaban G.A., Rudko D.A., Menon R.S., Iaci J.F., Button D.C., Vecchione A.M., Konovalov A., Sarmiere P.D., Ung C., Caggiano A.O., Kwon B.K. "The evaluation of magnesium chloride with a polyethyelene glycol formulation in a porcine model of acute spinal cord injury," Journal of Neurotrauma. December 2016; 33(24):2202-2216.
6. Rudko D.A, Derakhshan M., Maranzano J., Nakamura K. Arnold D.L., Narayanan S. "Delineation of cortical pathology in multiple sclerosis using multi-surface magnetization transfer ratio imaging," NeuroImage: Clinical. October 2016; 73(4):1654-1661.
7. Maranzano J., Rudko D.A., Arnold D.L., Narayanan S. "Manual segmentation of MS cortical lesions using MRI: A comparison of three MRI reading protocols," American Journal of Neuroradiology. September 2016; 37(9):1623-1628.
8. Junmin Liu, Rudko D.A., Gati J.S., Menon R.S., Drangova M. "Inter-echo variance as a weighting factor for multi-channel combination in multi-echo acquisition for local frequency shift mapping," Magnetic Resonance in Medicine. April 2015; 73(4):1654-1661.
9. Rudko D.A., Solovey I., Gati J.S., Kremenchutzky M., Menon R.S. "Multiple Sclerosis: improved identification of MS disease-relevant changes in gray and white matter using susceptibility-based MR imaging," Radiology. September 2014; 272(3):851:864.
10. Goubran M., Rudko D.A., Santyr B., Gati J., Szekeres T., Peters T.M., Khan A.R. "In vivo normative atlas of the hippocampal subfields using multi-echo susceptibility imaging at 7 Tesla," Human Brain Mapping. Aug. 2014; 35(8):3588-3601.
11. Rudko D.A., Racosta J., Kremenchutzky M. "Monitoring increased iron levels in multiple sclerosis using MRI," Future Neurology. July 2014; 9(4): 387-391.
12. Rudko D.A., Klassen L.M., de Chickera S.N., Gati J.S., Dekaban G.A., Menon R.S. "Origins of R2* orientation dependence in gray and white matter," Proceedings of the National Academy of Sciences of the United States of America. Jan 7, 2014;111(1):E159-67.
13. Campbell W.G., Rudko D.A., Braam N.A., Wells, D.M., Jirasek A. "A prototype fan-beam optical CT scanner for 3D dosimetry," Medical Physics. June 2013;40(6):061712.