Quantitative Magnetic Resonance Imaging - Mechanisms of Tissue Contrast
Magnetic Resonance Imaging (MRI) has proved to be a very useful and spectacular diagnostic tool that allows to image soft tissue non-invasively. Measured MRI signal characteristics depends on the physical and chemical processes experienced by water molecules in tissues. Our work involves studies that quantitatively characterize the MRI signal behaviour in various types of normal and pathological tissues in order to obtain information about tissue microstructure. Quantitative MRI can be used to estimate physical tissue parameters such as: cell dimensions, cell membranes permeabilities, translational and rotational motion of water in different tissue compartments (intra- and extracellular), extra- and intracellular volume fractions.
Current research involves measuring basic MR properties of tissue using a 7 T Bruker animal MRI system and developing tissue multi-compartmental models is order to correlate experimental data with tissue histopathology. We are particularly interested whether NMR measurements such as T1, T2 relaxation times, diffusion and Magnetization Transfer between water and macromolecules can be used to evaluate the processes of Central Nervous System pathologies and regeneration following stem cell therapies. Simultaneously, we use a clinical MR system (1.5 and 3T GE Signa) to develop diagnostic tools that would allow characterizing the CNS microstructure in vivo.
In addition we use MRI to monitor cancer therapies in animal model of cancer and in patients. In particular we are interested in evaluating changes in tumour vasculature and the processes of apoptosis using combined MRI and ultrasound imaging.
For further information, please visit homepage http://sunnybrook.ca/team/member.asp?t=13&m=163&page=172
Graduate Students:
- Colleen Bailey – “Quantitative MRI in evaluation of tumour apoptosis”
- Kim Desmond – “Chemical Exchange Saturation Transfer”
- Evelyn Lake – “Imaging Functional Recovery in Stroke using MRI and multi-photon imaging”
- Firas Moosvi – “Combined MRI/US imaging of animal models of breast cancer”
- Wendy Oakden –“Quantitative MRI of white matter”
Selected References:
Link to Pubmed Publications-
Stanisz GJ & Henkelman RM. 1998. Diffusional Anisotropy of T2 Components in Bovine Optic Nerve. Magn Reson Med. 40:405-410.
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Stanisz GJ, Kecojevic A, Bronskill MJ, Henkelman RM. 1999. Characterizing White Matter with Magnetization Transfer and T2 Relaxation. Magn. Reson.Med. 42: 1128-1136.
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Stanisz GJ & Henkelman RM “Gd-DTPA Relaxivity depends on macromolecular content”, Magn. Reson. Med. 44:665-667 (2000)
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Henkelman RM, STANISZ GJ, Graham SJ “Magnetization Transfer in MRI: A Review” NMR in Biomed. 14:57-64 (2001)
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Stanisz GJ, Midha R, Munro CA, Henkelman RM, “MR properties of rat sciatic nerve following trauma” Magn. Reson. Med. 45:415-420 (2001)
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Stanisz GJ, Yoon R, Joy M, Henkelman RM “Why does MTR change with neural depolarization?”, Magn Reson Med 47:472-475 (2002)
