Graham Wright

PhD, Stanford University

Sunnybrook Health Sciences Centre
2075 Bayview Avenue, M-Wing, Room M7-611, Toronto, Ontario Canada M4N 3M5
Research Interests
Biomedical Imaging, Cardiovascular Sciences, Image-Guided Therapy and Device Development, Stem Cells and Regenerative Medicine

At A Glance

Dr. Wright's research efforts include:

  • Basic biophysics to characterize the relationship between MR signals and underlying physiology in the heart, vasculature, and blood
  • Engineering to develop more effective methods to acquire, analyze, and visualize medical images
  • Application of these tools to assessment, treatment planning, and therapy guidance in ischemic heart diseases, complex arrhythmias, and peripheral vascular diseases

Short Bio

Graham A. Wright, PhD is a Senior Scientist at Sunnybrook Research Institute, a Professor in the Department of Medical Biophysics at the University of Toronto, and the Canada Research Chair in Imaging for Cardiovascular Therapeutics.

He recently completed 18 years as Research Director of the Schulich Heart Program at Sunnybrook Health Sciences Centre. He has also served as Chair of the SCMR Science Committee, President of the International MR Angiography Club and Chair of the Interventional Study Group of the International Society of Magnetic Resonance in Medicine.

The research focus of Dr. Wright’s group is cardiovascular imaging, with an emphasis on MRI. This effort includes basic biophysics to characterize the relationship between MR signals and underlying pathophysiology in blood and tissue; engineering to develop more effective methods and devices to acquire, analyze, and visualize medical images; and application of these tools to assessment, treatment planning, and therapy guidance in ischemic and structural heart diseases, complex arrhythmias, and peripheral vascular diseases. Through work with many clinical collaborators, these tools are being used in a wide range of patient studies.

Together with trainees and collaborators, he has published over 200 peer-reviewed papers and 525 conference abstracts, which have garnered numerous awards and resulted in 25 patents. For this work, he has received substantial peer-reviewed infrastructure and operating grant funding. Dr. Wright collaborates with a broad range of companies from start-ups to multi-nationals in translating research results toward clinical practice and has mentored numerous entrepreneurial trainees who have gone on to establish medical device companies.

Research Synopsis

MR Characterization of Arrhythmogenic Substrate and Radiofrequency ablations in the Heart: In 2007, we introduced a method for joint myocardial wall motion and viability characterization with a gated inversion-recovery SSFP method, yielding multiple images of varying T1 contrast across the cardiac cycle following Gadolinium injection and re-distribution. This method appears more robust and more sensitive to the detection of small and heterogeneous infarcts particularly near the endocardial border than existing techniques. Associated quantitative analysis tools yield more repeatable estimates of the extent of heterogeneous infarct, a measurement which reflects the risk of sudden cardiac death associated with complex arrhythmias, as demonstrated in a study following patients receiving implantable cardioverter defibrillators. Preclinical experiments directly probing the electrical properties of MRI-identified heterogeneous infarct, combined with computational modeling, suggests a potential causal link underlying this association. In the same preclinical model, we have demonstrated that MRI can help visualize at an acute stage ablative lesions aimed at eliminating the arrhythmogenic substrate. Particularly, we introduced a method exploiting native T1 contrast (patent pending) which appears to differentiate permanent from temporary lesions (depicted with T2 mapping) and scar, holding the promise of more effective guidance of potentially curative therapies.

MR-Guided Cardiovascular Interventions: We have developed real-time interactive visualization tools

in cooperation with colleagues at Stanford to establish a real-time MRI platform for cardiac applications (patent 6975751), which has been commercialized by a Stanford spin-off (HeartVista) for wider clinical study. This platform is central to our focus in MRI-guided electrophysiology interventions, involving several companies including Imricor Medical, which is developing MR-compatible electrophysiology catheters. These technologies have facilitated work showing direct correlation between MR-identified arrhythmogenic substrate and its electrical properties, as well as direct MR monitoring of ablations in heart tissue to eliminate such substrate. We have also developed novel technology to track devices (patents 7505808 and EP 23344364). Related to this, we have developed unique tools (patent pending) to monitor potential heating of conductive devices in the body during MR scans to ensure that MR-guided interventions can be performed safely.

Image Processing Methods for High-Resolution 3D MRI Acquisitions and Image Registration: In 2015, we introduced a novel spatially varying method (patent pending) to reduce noise in images while preserving edge information, with broad implications for image processing. This method has also been adapted to facilitate low rank constrained reconstruction of the inversion recovery SSFP sequence

described above, yielding high resolution 3D data sets in a breath hold that hold the potential for greater specificity in mapping arrhythmogenic substrate. The method has also been integrated into an approach to register real-time 2D MR images of the heart to prior 3D data sets, enabling respiratory motion correction for MR-guided cardiac interventions. Recently, we have also developed and evaluated tools based on convolutional neural nets for automatic segmentation of cardiac MRI data sets, yielding imaging biomarkers of anatomy and function.

Recent Publications

  1. M Ng, F Guo, L Biswas, SE Petersen, SK Piechnik, S Neubauer, G Wright. “Estimating Uncertainty in Neural Networks for Cardiac MRI Segmentation: A Benchmark Study”. IEEE Trans Biomed Eng. 2022 Dec 29;PP 1-12.
  2. Zhang L, Lai P, Pop M, Wright GA. “Multicontrast Volumetric Imaging with Isotropic Resolution for Assessing Infarct Heterogeneity: Initial Clinical Experience”, NMR In Biomedicine. 2020 Dec;33(12):e4253.
  3. Tavallaei MA, Zhou JJ, Roy TL, Wright GA. “Performance Assessment of a Radiofrequency Powered Guidewire for Crossing Peripheral Arterial Occlusions Based on Lesion Morphology”. Ann Biomed Eng. 2018 Jul;46(7):940-946.
  4. Ukwatta E, Nikolov P, Zabihollahy F, Trayanova N, Wright GA. “Virtual electrophysiological study as a tool for evaluating efficacy of MRI techniques in predicting adverse arrhythmic events in ischemic patients”. Physics in Medicine & Biology. 2018 Nov;63(22):225008.
  5. Roy TL, Chen HJ, Dueck AD, Wright GA. “Magnetic resonance imaging characteristics of lesions relate to the difficulty of peripheral arterial endovascular procedures”. J Vasc Surg. 2018 Jun;67(6):1844-1854.
  6. Krahn PRP, Singh SM, Ramanan V, Biswas L, Yak N, Anderson K, Barry J, Pop M, Wright GA. “Cardiovascular magnetic resonance guided ablation and intra-procedural visualization of evolving radiofrequency lesions in the left ventricle”. J of Cardiovascular Medicine. 2018 Mar 15;20(1):20.

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Graduate Students

Calder Sheagren – Department of Medical Biophysics, University of Toronto (PhD Candidate)
Area of Research: High Resolution Mapping for Improving Characterization of Myocardial Disease using MRI

Moses Cook - Department of Medical Biophysics, University of Toronto (PhD candidate)
Project area: MRI Monitoring Strategies for Cardiac Repair Therapies in Myocardial Infarction.

Jaykumar Patel – Department of Medical Biophysics, University of Toronto (PhD Candidate)
Project area: Real-time Registration of Prior Cardiac Volumes for MR-Guided Electrophysiology

Terenz Escartin – Department of Medical Biophysics, University of Toronto (PhD Candidate)
Project area: MRI for Complex Arrhythmia Management

Moujan Saderi – Department of Medical Biophysics, University of Toronto (MSc Candidate)
Project area: 2D/3D image registration for real-time guidance of percutaneous vascular interventions in below-the-knee vessels