Michela Tosetti
Director of Medical Physics and Magnetic Resonance Laboratory
Professor of Magnetic Resonance Physics
Stella Maris Scientific Institute and IMAGO7 Research Centre
(IRCCS Fondazione Stella Maris Pisa, a Research Scientific Institute of the Italian National Health System)

Title: Magnetic Resonance: hunting for quantitative measurements

Abstract: Magnetic Resonance (MR) is an effective tool for neuroscience, clinical diagnosis, staging, monitoring, treatment planning, and assessing response to therapy. Measurements of anatomical, physiological, and biochemical characteristics of the brain through MR used increasingly in neuroscience research, medical device development, as well in clinical decision-making. If we consider the MR scanner to be a scientific instrument, it is necessary to introduce the ideas of measurement theory: experiments measurements should be able to reveal subtle ‘invisible’ changes and should be characterized by accuracy (closeness to truth), reproducibility and repeatability (test-retest), and precision. Furthermore, a measurement should have enough specificity to be an indicator of normal biological and physiological processes of the brain, as well as the sensitivity to detect pathological and pathogenetic processes. Each measurement should be validated in normal and abnormal boundary conditions as well in single- or multi-site experiments. Different MR techniques could be used to provide both anatomical and functional information from the cellular level up to the entire brain. Thanks to improvements over the past years, these techniques have largely increased their temporal and spatial resolution, being now close to the physical limits of field strengths. The most commonly investigated parameters are longitudinal (T1) and transverse (T2) relaxation times, as well as water diffusion parameters which are able to explore structure and ultrastructure. These methods could be integrated with the information obtained by more sophisticated MR techniques investigating electromagnetic properties, regional blood flow and regional metabolic changes. Novel MR methods, especially at ultra-high field, have demonstrated the capabilities that can be brought to bear on measuring physiological brain changes, but the delineation of methods able to perform absolute measurements of the physics of brain processes in order to understand structure-function relationships in both neuroscience and disease states remains challenging. Hunting for brain quantitative measurements, we review some basic theoretical and technical considerations along with aspects related to the phenomenological signal modeling of Magnetic Resonance in studying the brain.

Bio-sketch: Michela Tosetti is a physicist who has dedicated her research career to the development of Magnetic Resonance (MR) for in vivo applications, with the specific interest of understanding cerebral mechanisms at various levels (structure, metabolism, function and connectivity) in order to define quantitative tools useful to better understand the complex anatomical, functional and organizational changes occurring in the brain, in particular during normal and abnormal development. In 1996 she personally contributed to setting up one of the first MR imaging centres in Italy, and has been Project Manager of the first installation (in 2011) of the only 7T MR human system in Italy. As Director of Medical Physics and Magnetic Resonance Laboratory of the Ultra High-Field Research Centre, she shares competence in a multidisciplinary manner and coordinates the complementary actions of people with very different professional backgrounds. She teaches Magnetic Resonance Physics at Pisa University since 2011, obtaining the Italian qualification of Full Professor in Applied Physics in 2013. She has a leading role in MR techniques and measurements in brain and in their clinical translation to the research of biomarkers in humans, coordinating the Italian methodological Researches in MR as well Grants and collaborations with both European and overseas MR groups.