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About Sickkids
About SickKids

Andrea Kassner, PhD

Research Institute
Senior Scientist
Translational Medicine

University of Toronto
Assistant Professor & Co-Director of Research
Department of Medical Imaging

Phone: 416-813-7654 ext. 302686
Fax: 416-813-7362
Email: andrea.kassner@sickkids.ca

For more information, visit:

Dr. Kassner's lab site

Brief Biography

Dr. Kassner received her PhD in 2002 from the University of Manchester, UK. Her thesis focused on tumour angiogenesis using dynamic susceptibility contrast-enhanced MRI. After working for Philips Medical Systems Europe for eight years as a MR Clinical Scientist, she joined the Department of Medical Imaging at the University of Toronto as an Assistant Professor in 2003. In 2006, Dr. Kassner was appointed Co-Director of Research, which was followed by her appointment as a Scientist in the Translational Medicine program at The Hospital for Sick Children. Her current research is focused on advancing MRI techniques for studying and monitoring two of the most devastating neurological disorders: stroke and intracranial neoplasm. Her current research projects include predicting hemorrhagic transformation in acute ischemic stroke using permeability MRI; mapping autoregulatory capacity using BOLD MRI in patients with chronic stroke; and examining gender differences in the corpus callosum using diffusion tensor imaging.

Research Interests

Advanced MR imaging techniques for studying and monitoring disease in the brain, especially:

  • Diffusion
  • Permeability
  • Contrast - enhanced perfusion (T1, T2*)
  • Arterial spin labeling (ASL)
  • BOLD
  • T2, T2*Mapping

Research Activities

  1. Ischemic Stroke
    Stroke is the third leading cause of death in North America and the primary cause of serious, long-term disability. The only available treatment option is t-PA (a clot-buster), but it increases the risk of intracranial bleeding if given beyond a certain time window (0-6 hours). Dr.Kassner is currently investigating if this limited treatment window can be widened using permeability MRI. She is using this technique to investigate defects in the blood-brain-barrier (an injury which occurs during stroke) and whether these defects can predict bleeding. Preliminary results have shown that early blood-brain-barrier defects in acute stroke can be assessed using permeability MRI. Significantly increased permeability was found only in cases which later on proceeded to bleeding. This indicates the potential of this method for identifying patients at higher risk for t-PA treatment even beyond the 6 hour time window. These findings may also be helpful in studying stroke in children.
  2. Chronic Stroke
    Moyamoya disease is a rare progressive cerebrovascular disorder caused by blocked arteries at the base of the brain. This will lead to increased development of small collateral vessels around the blocked arteries. These new vessels are chaotic and tortuous, and their angiography appearance, 'like a puff of smoke hanging in the air' gave rise to the term Moyamoya, which is derived from Japanese. Children are affected by this disorder when they are 3-4 years old, which results in transient strokes and intellectual deterioration. Dr.Kassner is currently investigating this disorder using combined inhaled CO2 manipulation with functional MRI. This will allow her to determine the location and extend of the abnormal vasculature. This information can then be used to guide surgical decision making.
  3. Brain Tumours
    Brain tumours are often highly aggressive (malignant) and affect both adults and children. In adults, 70-75 per cent are primary lesions and 25-30 per cent are metastases. In children, however, 99 per cent of lesions are primary brain tumours. Primary brain tumours rarely spread to other areas of the body, but they can spread to other parts of the brain and the spinal axis. Dr.Kassner uses physiological based MR imaging to characterize tumour vascular architecture. Parameters such as blood volume, blood flow, mean transit time and microvascular permeability are assessed and can be useful in evaluating histological grade and predicting therapeutic outcome.

External Funding

  • Canadian Institutes of Health Research (CIHR)
  • Medical Imaging Excellence and Research Award
  • Dean’s Fund, Faculty of Medicine


Widjaja E, Blaser S, Miller E, Kassner A, Shannon P, Chuang SH, Snead OC 3rd, Raybaud CR. (2007) Evaluation of subcortical white matter and deep white matter tracts in malformations of cortical development. Epilepsia.

Roberts TP, Liu F, Kassner A, Mori S, Guha A. (2005) Fiber density index correlates with reduced fractional anisotropy in white matter of patients with glioblastoma. AJNR 26: 2183-2186.

Kassner A, Roberts TPL, Taylor K, Silver F, Mikulis D. (2005) Prediction of hemorrhagic transformation in acute ischemic stroke using dynamic contrast-enhanced permeability MRI. AJNR 26: 2213-2217.

Mikulis DJ, Krolczyk G, Desal H, Logan W, Deveber G, Dirks P, Tymianski M, Crawley A, Vesely A, Kassner A, Preiss D, Somogyi R, Fisher JA. (2005) Preoperative and postoperative mapping of cerebrovascular reactivity in moyamoya disease by using blood oxygen level-dependent magnetic resonance imaging. J Neurosurgery 103(2): 347-55.

Kassner A and Roberts TP. (2004) Beyond perfusion: assessment of permeability and cerebral vascular reactivity. Top Magn Reson Imaging. 15(1):58-65.

Winter PM, Caruthers SD, Kassner A, Harris TD, Chinen LK, Allen JS, Zhang H, Robertson JD, Wickline SA, Lanza GM. (2003) Molecular Imaging of angiogenesis in nascent vx-2 rabbit tumors using a novel α (nu) β;3-targeted nanoparticle and 1.5T MRI. Cancer Research. 63: 1-6.

Kassner A, Zhu XP, Li KL, Jackson A. (2003) Neoangiogenesis in association with Moyamoya syndrome shown by estimation of relative recirculation based on dynamic contrast-enhanced MRI. American Journal of Neuroradiology. 24: 810-818.

Jackson A, Kassner A, Zhu XP, Li KL. (2002) Abnormalities in the recirculation phase of contrast bolus passage in cerebral gliomas: comparison with regional blood volume and tumour grade. American Journal of Neuroradiology. 23:7-14.

Jackson A, Kassner A, Zhu XP, Li KL. (2001) Reproducibility of T2* blood volume and vascular tortuosity maps in cerebral gliomas. Journal of Magn Reson. 14: 510-516.

Kassner A, Annesley DJ, Zhu X, Li KL, Kamali-Asl ID, Watson Y, Jackson A. (2000) Abnormalities of the contrast re-circulation phase in cerebral tumours demonstrated using dynamic susceptibility contrast enhanced MR imaging: A possible marker for vascular tortuosity. Journal of Magn Reson. 11: 103-113.