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  • Charles A. Mistretta, PhD

  • (This biography from Hedvig Hricak, MD, PhD, Dr(hc) originally appeared in Radiology)

    Charles A. Mistretta, PhD, is a brilliant and prolific investigator who has transformed medical imaging and human health throughout his career, with groundbreaking contributions at multiple times and in multiple subfields.  

    The influence of Dr Mistretta—director of the world-renowned International Center for Accelerated Medical Imaging at the University of Wisconsin (Madison, Wis)—will be felt for years beyond his retirement, as he has enthusiastically and unselfishly shared his knowledge, ideas, and research style with the dozens of exceptional researchers he has mentored.  

    For many, the first thing that comes to mind when they hear Dr Mistretta’s name is digital subtraction angiography (DSA). His research in this area dates to 1971, when he and colleagues began studies of dual energy x-ray imaging by using analog storage tube devices. This led to the development of a real-time digital image processor, the enabling device for what eventually became DSA.  

    “Initial enthusiasm for this technique was based on the hope that angiography could be done with intravenous injections,” Dr Mistretta notes. “However, problems with artery-vein overlap led the medical community to use intraarterial DSA. This permitted the use of lower contrast [agent] doses and smaller catheters and resulted in a substantial reduction in angiographic complications and provided a tool for the development of interventional radiology.”  

    The team’s DSA technique has been distributed worldwide and is still the standard against which the image quality of new angiographic techniques is measured. Patent royalties from DSA presently rank second among all inventions in the history of the University of Wisconsin, where Dr Mistretta has spent his career and currently serves as John R. Cameron Professor of Medical Physics and vice-chairman of the Department of Medical Physics, in addition to his role as director of the center.  

    Dr Mistretta received his BS degree in engineering physics from the University of Illinois (Urbana-Champaign, Ill) and his MS degree in physics and PhD degree in high-energy physics from Harvard University (Boston, Mass).  

    Beginning in 1988, Dr Mistretta successfully applied his abilities as an innovator and collaborator to magnetic resonance (MR) angiography, leading his team to develop a number of breakthrough techniques for fast acquisition and processing of data: (a) 3D TRICKS (three-dimensional [3D] time-resolved imaging of contrast kinetics), currently the preferred commercial method for time-resolved MR angiography; (b) undersampled 3D radial acquisition; (c) VIPR (vastly undersampled isotropic projection imaging), which permits data acquisition accelerations of one to two orders of magnitude relative to that of conventional cartesian acquisitions; (d) HYPR (highly constrained reconstruction from projections), which provides further undersampling factors and substantial increases in signal-to-noise ratio; (e) phase-contrast VIPR, which permits high-resolution flow measurements and determination of transstenotic pressure gradients; and (f) hybrid MR angiography, which provides acceleration factors up to 1000 relative to conventional MR angiography.  

    Dr. Mistretta and his team at the International Center for Accelerated Medical Imaging have recently helped other investigators around the world extend these techniques to other modalities, including positron emission tomography, photoacoustic tomography, and x-ray computed tomography (CT). A factor-of-10 perfusion dose reduction for CT has been reported in several studies.  

    The latest development is four dimensional DSA, introduced by Dr Mistretta and colleague Charles Strother, MD. “This method provides time-resolved rotational DSA images at time-resolved frame rates of up to 30 per second, instead of the usual time independent rotational DSA image volume obtained in times of 5 to 20 seconds,” notes Dr Mistretta. “The technique also permits real-time catheter tracking with viewing at arbitrary angles without ongoing gantry rotation.”  

    Dr Mistretta is known for producing innovations that are eminently practical and for his ability to articulate complex concepts equally easily to technical colleagues and business leaders. He has generated 33 issued U.S. patents, with 13 additional patents pending.  

    Just as important as his contributions to imaging science is his dedicated mentorship of 30 doctoral students and supervision of 23 postdoctoral fellows, a “who’s who” of diagnostic imaging scientists who have reached international prominence as directors of major research laboratories and in other capacities. Dr Mistretta is a role model for how someone should conduct research, approaching problems with both creativity and rigor; moreover, he is a powerful leader—his easygoing and modest personality engages his younger colleagues and students as equals.  

    Dr Mistretta has authored and coauthored hundreds of articles published in peer-reviewed journals, as well as book chapters and abstracts presented at scientific meetings.  

    For his achievements, he has been honored as a fellow of the American Association of Physicists in Medicine, the American Institute for Medical and Biologic Engineering, and the International Society for Magnetic Resonance in Medicine. He has received the Laufman-Greatbatch Prize from the Association for the Advancement of Medical Instrumentation and the J. Allyn Taylor International Prize in Medicine from the Robarts Research Institute and the University of Western Ontario (London, Ontario, Canada). He recently received the 2010 Technology Achievement Award from the Massachusetts Institute of Technology (Boston) Club of Wisconsin. The Radiological Society of North America is pleased to add Outstanding Researcher to Dr Mistretta’s accolades.  

    While some speculate about the effect he will have in the new millennium through his former students, it is clear he will still be making his own direct contributions for the foreseeable future. In materials submitted to RSNA after he learned he was to receive the Outstanding Researcher Award, Dr Mistretta noted that he plans to retire “as soon as elephants learn to fly.”