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1. Considerations and recommendations from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 3 -- Ex vivo imaging: data processing, comparisons with microscopy, and tractography

Author

Schilling, Kurt G, Howard, Amy FD, Grussu, Francesco, Ianus, Andrada, Hansen, Brian, Barrett, Rachel L C, Aggarwal, Manisha, Michielse, Stijn, Nasrallah, Fatima, Syeda, Warda, Wang, Nian, Veraart, Jelle, Roebroeck, Alard, Bagdasarian, Andrew F, Eichner, Cornelius, Sepehrband, Farshid, Zimmermann, Jan, Soustelle, Lucas, Bowman, Christien, Tendler, Benjamin C, Hertanu, Andreea, Jeurissen, Ben, Verhoye, Marleen, Frydman, Lucio, van de Looij, Yohan, Hike, David, Dunn, Jeff F, Miller, Karla, Landman, Bennett A, Shemesh, Noam, Anderson, Adam, McKinnon, Emilie, Farquharson, Shawna, Acqua, Flavio Dell', Pierpaoli, Carlo, Drobnjak, Ivana, Leemans, Alexander, Harkins, Kevin D, Descoteaux, Maxime, Xu, Duan, Huang, Hao, Santin, Mathieu D, Grant, Samuel C., Obenaus, Andre, Kim, Gene S, Wu, Dan, Bihan, Denis Le, Blackband, Stephen J, Ciobanu, Luisa, Fieremans, Els, Bai, Ruiliang, Leergaard, Trygve B, Zhang, Jiangyang, Dyrby, Tim B, Johnson, G Allan, Cohen-Adad, Julien, Budde, Matthew D, and Jelescu, Ileana O

Subjects
Physics - Medical Physics
Abstract

Preclinical diffusion MRI (dMRI) has proven value in methods development and validation, characterizing the biological basis of diffusion phenomena, and comparative anatomy. While dMRI enables in vivo non-invasive characterization of tissue, ex vivo dMRI is increasingly being used to probe tissue microstructure and brain connectivity. Ex vivo dMRI has several experimental advantages that facilitate high spatial resolution and high signal-to-noise ratio (SNR) images, cutting-edge diffusion contrasts, and direct comparison with histological data as a methodological validation. However, there are a number of considerations that must be made when performing ex vivo experiments. The steps from tissue preparation, image acquisition and processing, and interpretation of results are complex, with many decisions that not only differ dramatically from in vivo imaging of small animals, but ultimately affect what questions can be answered using the data. This work concludes a 3-part series of recommendations and considerations for preclinical dMRI. Herein, we describe best practices for dMRI of ex vivo tissue, with a focus on image pre-processing, data processing and model fitting, and tractography. In each section, we attempt to provide guidelines and recommendations, but also highlight areas for which no guidelines exist (and why), and where future work should lie. We end by providing guidelines on code sharing and data sharing, and point towards open-source software and databases specific to small animal and ex vivo imaging., Comment: Part 3 of 3 in "Considerations and recommendations for preclinical diffusion MRI"

Published
2024

3. Considerations and recommendations from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 2 -- Ex vivo imaging: added value and acquisition

Author

Schilling, Kurt G, Grussu, Francesco, Ianus, Andrada, Hansen, Brian, Howard, Amy FD, Barrett, Rachel L C, Aggarwal, Manisha, Michielse, Stijn, Nasrallah, Fatima, Syeda, Warda, Wang, Nian, Veraart, Jelle, Roebroeck, Alard, Bagdasarian, Andrew F, Eichner, Cornelius, Sepehrband, Farshid, Zimmermann, Jan, Soustelle, Lucas, Bowman, Christien, Tendler, Benjamin C, Hertanu, Andreea, Jeurissen, Ben, Frydman, Lucio, van de Looij, Yohan, Hike, David, Dunn, Jeff F, Miller, Karla, Landman, Bennett A, Shemesh, Noam, Anderson, Adam, McKinnon, Emilie, Farquharson, Shawna, Acqua, Flavio Dell', Pierpaoli, Carlo, Drobnjak, Ivana, Leemans, Alexander, Harkins, Kevin D, Descoteaux, Maxime, Xu, Duan, Huang, Hao, Santin, Mathieu D, Grant, Samuel C., Obenaus, Andre, Kim, Gene S, Wu, Dan, Bihan, Denis Le, Blackband, Stephen J, Ciobanu, Luisa, Fieremans, Els, Bai, Ruiliang, Leergaard, Trygve, Zhang, Jiangyang, Dyrby, Tim B, Johnson, G Allan, Cohen-Adad, Julien, Budde, Matthew D, and Jelescu, Ileana O

Subjects
Physics - Medical Physics, Quantitative Biology - Tissues and Organs
Abstract

The value of preclinical diffusion MRI (dMRI) is substantial. While dMRI enables in vivo non-invasive characterization of tissue, ex vivo dMRI is increasingly used to probe tissue microstructure and brain connectivity. Ex vivo dMRI has several experimental advantages including higher signal-to-noise ratio and spatial resolution compared to in vivo studies, and enabling more advanced diffusion contrasts. Another major advantage of ex vivo dMRI is the direct comparison with histological data as a methodological validation. However, there are a number of considerations that must be made when performing ex vivo experiments. The steps from tissue preparation, image acquisition and processing, and interpretation of results are complex, with decisions that not only differ dramatically from in vivo imaging of small animals, but ultimately affect what questions can be answered using the data. This work represents "Part 2" of a 3-part series of recommendations and considerations for preclinical dMRI. We describe best practices for dMRI of ex vivo tissue, with a focus on the value that ex vivo imaging adds to the field of dMRI and considerations in ex vivo image acquisition. We give general considerations and foundational knowledge that must be considered when designing experiments. We describe differences in specimens and models and discuss why some may be more or less appropriate for different studies. We then give guidelines for ex vivo protocols, including tissue fixation, sample preparation, and MR scanning. In each section, we attempt to provide guidelines and recommendations, but also highlight areas for which no guidelines exist (and why), and where future work should lie. An overarching goal herein is to enhance the rigor and reproducibility of ex vivo dMRI acquisitions and analyses, and thereby advance biomedical knowledge., Comment: Part 2 of 3 in "Considerations and recommendations for preclinical diffusion MRI"

Published
2022

4. Considerations and Recommendations from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 1 -- In vivo small-animal imaging

Author

Jelescu, Ileana O, Grussu, Francesco, Ianus, Andrada, Hansen, Brian, Barrett, Rachel L C, Aggarwal, Manisha, Michielse, Stijn, Nasrallah, Fatima, Syeda, Warda, Wang, Nian, Veraart, Jelle, Roebroeck, Alard, Bagdasarian, Andrew F, Eichner, Cornelius, Sepehrband, Farshid, Zimmermann, Jan, Soustelle, Lucas, Bowman, Christien, Tendler, Benjamin C, Hertanu, Andreea, Jeurissen, Ben, Verhoye, Marleen, Frydman, Lucio, van de Looij, Yohan, Hike, David, Dunn, Jeff F, Miller, Karla, Landman, Bennett A, Shemesh, Noam, Anderson, Adam, McKinnon, Emilie, Farquharson, Shawna, Acqua, Flavio Dell', Pierpaoli, Carlo, Drobnjak, Ivana, Leemans, Alexander, Harkins, Kevin D, Descoteaux, Maxime, Xu, Duan, Huang, Hao, Santin, Mathieu D, Grant, Samuel C., Obenaus, Andre, Kim, Gene S, Wu, Dan, Bihan, Denis Le, Blackband, Stephen J, Ciobanu, Luisa, Fieremans, Els, Bai, Ruiliang, Leergaard, Trygve B, Zhang, Jiangyang, Dyrby, Tim B, Johnson, G Allan, Cohen-Adad, Julien, Budde, Matthew D, and Schilling, Kurt G

Subjects
Physics - Medical Physics, Quantitative Biology - Tissues and Organs
Abstract

Small-animal diffusion MRI (dMRI) has been used for methodological development and validation, characterizing the biological basis of diffusion phenomena, and comparative anatomy. The steps from animal setup and monitoring, to acquisition, analysis, and interpretation are complex, with many decisions that may ultimately affect what questions can be answered using the resultant data. This work aims to present selected recommendations and guidelines from the diffusion community, on best practices for preclinical dMRI of in vivo animals. We describe the general considerations and foundational knowledge that must be considered when designing experiments. We briefly describe differences in animal species and disease models and discuss why some may be more or less appropriate for different studies. We then give guidelines for in vivo acquisition protocols, including decisions on hardware, animal preparation, and imaging sequences, followed by advice for data processing including pre-processing, model-fitting, and tractography. Finally, we provide an online resource which lists publicly available preclinical dMRI datasets and software packages, to promote responsible and reproducible research. In each section, we attempt to provide guides and recommendations, but also highlight areas for which no guidelines exist (and why), and where future work should focus. While we mainly cover the central nervous system (on which most preclinical dMRI studies are focused), we also provide, where possible and applicable, recommendations for other organs of interest. An overarching goal herein is to enhance the rigor and reproducibility of small animal dMRI acquisitions and analyses, and thereby advance biomedical knowledge., Comment: 47 pages, 5 figures, 1 table

Published
2022

5. The influence of COVID-19 on the learning and developing processes of practical skills in military educational institutions

Author

Maria Cristina Bularca, Stefania Bumbuc, Ghita Barsan, Claudiu Coman, Alexandru Bucoi, Andreea Hertanu, Adrian Netedu, and Ioan Aron

Subjects
leadership, styles, organizational change, COVID-19 pandemic, higher education, Education (General), L7-991
Abstract

During the COVID-19 pandemic, the educational process in military higher education institutions underwent changes, especially in terms of carrying out practical activities. The purpose of the research was to analyze how the COVID-19 pandemic influenced the educational process and the leadership activities carried out in a Romanian military academy, in the context in which the practical activities had to be carried out in the online environment. Practical skills play an important role in the life of military students and they can help them within the process of becoming efficient leaders. In the context of the research, practical skills refer to decision-making abilities, conflict resolution skills, communication skills, the ability to delegate, or the capacity to motivate and inspire others. In order to conduct the research, we used a quantitative approach. A questionnaire was applied to 288 students of “Nicolae Bălcescu” Land Forces Academy from Sibiu, Romania. The results of the research revealed that students pointed out the difficulty of interacting with their teachers, and of developing practical activities. While the opinions of the students were not influenced by their gender, they were influenced by the type of studies followed. Compared to bachelor students, master students were more affected by the changes which took place, and they believed to a higher extent that they possess leadership skills and that they have the necessary knowledge to lead a specific military group.

Published
2024
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6. Institutional, Ecological, Economic, and Socio-Cultural Sustainability—Evidence from Ponjavica Nature Park

Author

Vladica Ristić, Igor Trišić, Snežana Štetić, Marija Maksin, Florin Nechita, Adina Nicoleta Candrea, Marko Pavlović, and Andreea Hertanu

Subjects
residents and visitors satisfaction, special nature reserve, prism of sustainability, protected natural asset, Agriculture
Abstract

The Nature Park Ponjavica (NP) is the habitat of strictly protected plant and animal species, located in AP Vojvodina, in southern Banat (Northern Serbia). The area of the park covers 302.96 ha. Protection zones I, II, and III have been established in the protected area of the NP. The NP includes the middle course of the Ponjavica River, which has preserved characteristics of watercourses of plain areas and coastal remains of wetland habitats. The most valuable area of this park in terms of protection is an island with an area of slightly less than 1 hectare. According to the IUCN (International Union for Conservation of Nature), the NP is classified as the fourth category—Habitat and species management area. The good geographical position of NP is one of its main characteristics. The NP can be a destination where specific forms of tourism can be developed, such as ecotourism, nature-based tourism, birdwatching, scientific and research tourism, etc. Numerous historical sites represent a significant potential for the development of cultural tourism. The research examined the influence of institutional, economic, ecological, and socio-cultural sustainability on the respondents’ satisfaction. The quantitative methodology in this research included a questionnaire as a survey instrument for respondents. A total of 547 residents were surveyed. The results of the research indicate that there is considerable satisfaction among residents with sustainable tourism. The results of the research can help in the development of numerous tourism development strategies in which the wetland is the primary resource.

Published
2024
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8. Comparative evaluation of florfenicol and polymeric nanopar-ticles loaded with florfenicol against bacterial strains isolated from chickens: insights into antimicrobial resistance

Author

Emilia Trif, Constatin Cerbu, Marina spinu, Diana Ioana Olah, Adrian Valentin Potarniche, Sergiu-Dan Zablau, Florina Marian, George Hertanu, Emoke Pall, and Gheorghe Florinel Brudasca

Subjects
florfenicol, antibiotic-loaded nanoparticles, antimicrobial resistance, Veterinary medicine, SF600-1100
Abstract

Antimicrobial resistance (AMR) poses a significant threat to both human and animal health, necessitating the search for alternative antimicrobial agents and strategies. In this study, we aimed to identify and isolate clinical bacterial strains from chickens and evaluate their sensitivity to florfenicol, a common antimicrobial agent that is used exclusively in veterinary medicine, along with polymeric nanoparticles loaded with florfenicol at various concentrations. Three clinical bacterial strains were successfully isolated and identified from chicken presenting clinical signs. In order to assess their susceptibility, the isolated strains were subjected to a standard disc diffusion assay using florfenicol. Subsequently, polymeric nanoparticles loaded with florfenicol were tested at six different concentrations and compared their efficacy against the bacterial strains. Our results demonstrated that all three clinical bacterial strains exhibited varying degrees of resistance to florfenicol. Interestingly, the use of polymeric nanoparticles loaded with florfenicol did not display enhanced antimicrobial activity compared to the free drug. Notably, the efficacy of the loaded nanoparticles did not significantly vary with different concentrations of active substance. This study highlights the importance of exploring novel therapeutic approaches to combat antimicrobial resistance. The use of polymeric nanoparticles loaded with florfenicol presents a promising avenue for overcoming resistance mechanisms and improving the efficacy of antimicrobial treatments both in human and veterinary medicine. Further investigations are needed to elucidate the underlying mechanisms and optimize the formulation of polymer nanoparticles for enhanced therapeutic outcomes in combating AMR.

Published
2023
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15. Quantitative magnetization transfer MRI unbiased by on‐resonance saturation and dipolar order contributions

Author

Lucas Soustelle, Thomas Troalen, Andreea Hertanu, Jean‐Philippe Ranjeva, Maxime Guye, Gopal Varma, David C. Alsop, Guillaume Duhamel, Olivier M. Girard, Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - APHM] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE)-Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Siemens Healthcare [France], Siemens AG [Munich], Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA, ANR-22-CE17-0060,NormaBRAIN,IRM quantitative et base normative pour la caractérisation des altérations tissulaires cérébrales à haut et ultra-haut champ magnétique(2022), ANR-22-CE18-0041,ULTIMO,Imagerie quantitative des membranes lipidiques par ihMT: un nouveau marqueur IRM de la myéline(2022), ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017), and ANR-11-INBS-0006,FLI,France Life Imaging(2011)

Subjects
neuroimaging, T1 relaxometry, quantitative magnetization transfer, Radiology, Nuclear Medicine and imaging, [SDV.IB]Life Sciences [q-bio]/Bioengineering, dipolar order, inhomogeneous magnetization transfer
Abstract

International audience; To demonstrate the bias in quantitative MT (qMT) measures introduced by the presence of dipolar order and on-resonance saturation (ONRS) effects using magnetization transfer (MT) spoiled gradient-recalled (SPGR) acquisitions, and propose changes to the acquisition and analysis strategies to remove these biases. Methods: The proposed framework consists of SPGR sequences prepared with simultaneous dual-offset frequency-saturation pulses to cancel out dipolar order and associated relaxation (T 1D) effects in Z-spectrum acquisitions, and a matched quantitative MT (qMT) mathematical model that includes ONRS effects of readout pulses. Variable flip angle and MT data were fitted jointly to simultaneously estimate qMT parameters (macromolecular proton fraction [MPF], T 2,f , T 2,b , R, and free pool T 1). This framework is compared with standard qMT and investigated in terms of reproducibility, and then further developed to follow a joint single-point qMT methodology for combined estimation of MPF and T 1. Results: Bland-Altman analyses demonstrated a systematic underestimation of MPF (−2.5% and −1.3%, on average, in white and gray matter, respectively) and overestimation of T 1 (47.1 ms and 38.6 ms, on average, in white and gray matter, respectively) if both ONRS and dipolar order effects are ignored. Reproducibility of the proposed framework is excellent (ΔMPF = −0.03% and ΔT 1 = −19.0 ms). The single-point methodology yielded consistent MPF and T 1 values with respective maximum relative average bias of −0.15% and −3.5 ms found in white matter. Conclusion: The influence of acquisition strategy and matched mathematical model with regard to ONRS and dipolar order effects in qMT-SPGR frameworks has been investigated. The proposed framework holds promise for improved accuracy with reproducibility.

Published
2023
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16. The Effects of the Pandemics on Ethnic Roma

Author

Margareta Hertanu

Subjects
Pharmacology (medical)
Abstract

This article shows aspects captured in the research conducted at the beginning of 2021 with Roma ethnics from Iasi County and refers to the effects of the pandemic on Roma ethnics. For a start, the paper presents a short history of the Roma, their origins, their migrations around the world, the way they arrived on Romanian territory. The period of slavery of the Roma, their liberation, carried out by the ruler Alexandru Ioan Cuza around 1860, the period of the Holocaust in the Second World War, when due to a racist doctrine adopted by the Romanian State, the Roma were deported and subjected an extermination program, overcoming these unfortunate periods. The article also includes a brief description of the Roma from Iasi County and from the city of Iasi, continuing with the representation of the disease in the Roma; what does the disease mean for the Roma, how can they avoid it, what measures do they take to defend themselves against the disease, what kind of practical medicine. The article presents the research method used, the most suitable for the research group, this being the focus group. The subjects that were chosen for research are described and then the effects of the pandemic on Roma ethnics are presented, on a social, personal and psychological level. What they experienced from a social point of view during the pandemic, how social events unfolded for them, how they related socially; personally, how they managed this challenge from a personal point of view, what changes or improvements caused the pandemic; psychologically the feelings they had, the feelings they tried, the psychological struggle that took place inside them. The conclusions conclude this article by showing what the pandemic meant for the Roma ethnics and how they overcame it.

Published
2022
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17. T 1D ‐weighted ihMT imaging – Part I. Isolation of long‐ and short‐T 1D components by T 1D ‐filtering

Author

Andreea Hertanu, Lucas Soustelle, Arnaud Le Troter, Julie Buron, Julie Le Priellec, Victor N. D. Carvalho, Myriam Cayre, Pascale Durbec, Gopal Varma, David C. Alsop, Olivier M. Girard, Guillaume Duhamel, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess Medical Center [Boston] (BIDMC), Harvard Medical School [Boston] (HMS), ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017), and ANR-11-INBS-0006,FLI,France Life Imaging(2011)

Subjects
[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Radiology, Nuclear Medicine and imaging
Abstract

International audience; PurposeTo identify T1D-filtering methods, which can specifically isolate various ranges of T1D components as they may be sensitive to different microstructural properties.MethodsModified Bloch-Provotorov equations describing a bi-T1D component biophysical model were used to simulate the inhomogeneous magnetization transfer (ihMT) signal from ihMTRAGE sequences at high RF power and low duty-cycle with different switching time values for the dual saturation experiment: Δt = 0.0, 0.8, 1.6, and 3.2 ms. Simulations were compared with experimental signals on the brain gray and white matter tissues of healthy mice at 7T.ResultsThe lengthening of Δt created ihMT high-pass T1D-filters, which efficiently eliminated the signal from T1D components shorter than 1 ms, while partially attenuating that of longer components (≥ 1 ms). Subtraction of ihMTR images obtained with Δt = 0.0 ms and Δt = 0.8 ms generated a new ihMT band-pass T1D-filter isolating short-T1D components in the 100-µs to 1-ms range. Simulated ihMTR values in central nervous system tissues were confirmed experimentally.ConclusionLong- and short-T1D components were successfully isolated with high RF power and low duty-cycle ihMT filters in the healthy mouse brain. Future studies should investigate the various T1D-range microstructural correlations in in vivo tissues.

Published
2022
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20. Inhomogeneous Magnetization Transfer (ihMT) imaging in the acute cuprizone mouse model of demyelination/remyelination

Author

Andreea Hertanu, Lucas Soustelle, Julie Buron, Julie Le Priellec, Myriam Cayre, Arnaud Le Troter, Valentin H. Prevost, Jean-Philippe Ranjeva, Gopal Varma, David C. Alsop, Pascale Durbec, Olivier M. Girard, Guillaume Duhamel, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - APHM] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE)-Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess Medical Center [Boston] (BIDMC), and Harvard Medical School [Boston] (HMS)

Subjects
Neurology, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Cognitive Neuroscience
Abstract

To investigate the association of ihMT (inhom signals with the demyelination and remyelination phases of the acute cuprizone mouse model in comparison with histology, and to assess the extent of tissue damage and repair from MRI data.Acute demyelination by feeding 0.2% cuprizone for five weeks, followed by a four-week remyelination period was applied on genetically modified plp-GFP mice. Animals were scanned at different time points of the demyelination and remyelination phases of the cuprizone model using a multimodal MRI protocol, including ihMT TIhMT high-pass TIhMT sequences selective for long T

Published
2022
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21. T 1D ‐weighted ihMT imaging – Part II. Investigating the long‐ and short‐T 1D components correlation with myelin content. Comparison with R 1 and the macromolecular proton fraction

Author

Hertanu, Andreea, Soustelle, Lucas, Buron, Julie, Le Priellec, Julie, Cayre, Myriam, Le Troter, Arnaud, Varma, Gopal, Alsop, David, Durbec, Pascale, Girard, Olivier, Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess Medical Center [Boston] (BIDMC), Harvard Medical School [Boston] (HMS), ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017), and ANR-11-INBS-0006,FLI,France Life Imaging(2011)

Subjects
endocrine system, endocrine system diseases, immune system diseases, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, nutritional and metabolic diseases
Abstract

International audience; PurposeTo investigate the long- and short-T1D components correlation with myelin content using inhomogeneous magnetization transfer (ihMT) high-pass and band-pass T1D-filters and to compare ihMT, R1, and the macromolecular proton fraction (MPF) for myelin specific imaging.MethodsThe 3D ihMT rapid gradient echo (ihMTRAGE) sequences with increasing switching times (Δt) were used to derive ihMT high-pass T1D-filters with increasing T1D cutoff values and an ihMT band-pass T1D-filter for components in the 100 µs to 1 ms range. 3D spoiled gradient echo quantitative MT (SPGR-qMT) protocols were used to derive R1 and MPF maps. The specificity of R1, MPF, and ihMT T1D-filters was evaluated by comparison with two histological reference techniques for myelin imaging.ResultsThe higher contribution of long-T1Ds as compared to the short components as Δt got longer led to an increase in the specificity to myelination. In contrast, focusing on the signal originating from a narrow range of short-T1Ds (< 1 ms) as isolated by the band-pass T1D-filter led to lower specificity. In addition, the significantly lower r2 correlation coefficient of the band-pass T1D-filter suggests that the origin of short-T1D components is mostly associated with non-myelin protons. Also, the important contribution of short-T1Ds to the estimated MPF, explains its low specificity to myelination as compared to the ihMT high-pass T1D-filters.ConclusionLong-T1D components imaging by means of ihMT high-pass T1D-filters is proposed as an MRI biomarker for myelin content. Future studies should enable the investigation of the sensitivity of ihMT T1D-filters for demyelinating processes.

Published
2022
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22. Quantitative T1D assessment in lipid membranes: Jeener-Broekaert NMR vs. ihMT MRI

Author

Hertanu, A., Soustelle, Lucas, de Rochefort, Ludovic, Grélard, Axelle, Dufourc, Erick J., Alsop, David, Duhamel, Guillaume, Girard, Olivier M., de Rochefort, Ludovic, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - APHM] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE)-Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), Université de Bordeaux (UB)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Division of MR Research, Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

Subjects
[PHYS]Physics [physics], [SDV] Life Sciences [q-bio], [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], [SDV]Life Sciences [q-bio], [PHYS] Physics [physics]
Abstract

International audience; The dipolar order relaxation time (T1D) is a probe of membrane dynamics and microstructure and could serve to further understand the relationship between the myelin membrane integrity and its biological function. In this work, the ability of quantitative inhomogeneous Magnetization Transfer (qihMT) to estimate the several T1D components of a synthetic lipid membrane system, a surrogate for the myelin membrane, was evaluated by comparison with the gold standard method for T1D quantification, the NMR Jeener-Broekaert (JB) sequence.

Published
2022

23. Recommendations and guidelines from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 1 -- In vivo small-animal imaging

Author

Jelescu, Ileana O, Grussu, Francesco, Ianus, Andrada, Hansen, Brian, Barrett, Rachel L C, Aggarwal, Manisha, Michielse, Stijn, Nasrallah, Fatima, Syeda, Warda, Wang, Nian, Veraart, Jelle, Roebroeck, Alard, Bagdasarian, Andrew F, Eichner, Cornelius, Sepehrband, Farshid, Zimmermann, Jan, Soustelle, Lucas, Bowman, Christien, Tendler, Benjamin C, Hertanu, Andreea, Jeurissen, Ben, Verhoye, Marleen, Frydman, Lucio, van de Looij, Yohan, Hike, David, Dunn, Jeff F, Miller, Karla, Landman, Bennett A, Shemesh, Noam, Anderson, Adam, McKinnon, Emilie, Farquharson, Shawna, Acqua, Flavio Dell', Pierpaoli, Carlo, Drobnjak, Ivana, Leemans, Alexander, Harkins, Kevin D, Descoteaux, Maxime, Xu, Duan, Huang, Hao, Santin, Mathieu D, Grant, Samuel C., Obenaus, Andre, Kim, Gene S, Wu, Dan, Bihan, Denis Le, Blackband, Stephen J, Ciobanu, Luisa, Fieremans, Els, Bai, Ruiliang, Leergaard, Trygve, Zhang, Jiangyang, Dyrby, Tim B, Johnson, G Allan, Cohen-Adad, Julien, Budde, Matthew D, and Schilling, Kurt G

Subjects
FOS: Biological sciences, FOS: Physical sciences, Quantitative Biology - Tissues and Organs, Medical Physics (physics.med-ph), Tissues and Organs (q-bio.TO), Physics - Medical Physics
Abstract

The value of in vivo preclinical diffusion MRI (dMRI) is substantial. Small-animal dMRI has been used for methodological development and validation, characterizing the biological basis of diffusion phenomena, and comparative anatomy. Many of the influential works in this field were first performed in small animals or ex vivo samples. The steps from animal setup and monitoring, to acquisition, analysis, and interpretation are complex, with many decisions that may ultimately affect what questions can be answered using the data. This work aims to serve as a reference, presenting selected recommendations and guidelines from the diffusion community, on best practices for preclinical dMRI of in vivo animals. In each section, we also highlight areas for which no guidelines exist (and why), and where future work should focus. We first describe the value that small animal imaging adds to the field of dMRI, followed by general considerations and foundational knowledge that must be considered when designing experiments. We briefly describe differences in animal species and disease models and discuss how they are appropriate for different studies. We then give guidelines for in vivo acquisition protocols, including decisions on hardware, animal preparation, imaging sequences and data processing, including pre-processing, model-fitting, and tractography. Finally, we provide an online resource which lists publicly available preclinical dMRI datasets and software packages, to promote responsible and reproducible research. An overarching goal herein is to enhance the rigor and reproducibility of small animal dMRI acquisitions and analyses, and thereby advance biomedical knowledge., Comment: 69 pages, 6 figures, 1 table

Published
2022
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24. Recommendations and guidelines from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 2 -- Ex vivo imaging

Author

Schilling, Kurt G, Grussu, Francesco, Ianus, Andrada, Hansen, Brian, Barrett, Rachel L C, Aggarwal, Manisha, Michielse, Stijn, Nasrallah, Fatima, Syeda, Warda, Wang, Nian, Veraart, Jelle, Roebroeck, Alard, Bagdasarian, Andrew F, Eichner, Cornelius, Sepehrband, Farshid, Zimmermann, Jan, Soustelle, Lucas, Bowman, Christien, Tendler, Benjamin C, Hertanu, Andreea, Jeurissen, Ben, Frydman, Lucio, van de Looij, Yohan, Hike, David, Dunn, Jeff F, Miller, Karla, Landman, Bennett A, Shemesh, Noam, Anderson, Adam, McKinnon, Emilie, Farquharson, Shawna, Acqua, Flavio Dell', Pierpaoli, Carlo, Drobnjak, Ivana, Leemans, Alexander, Harkins, Kevin D, Descoteaux, Maxime, Xu, Duan, Huang, Hao, Santin, Mathieu D, Grant, Samuel C., Obenaus, Andre, Kim, Gene S, Wu, Dan, Bihan, Denis Le, Blackband, Stephen J, Ciobanu, Luisa, Fieremans, Els, Bai, Ruiliang, Leergaard, Trygve, Zhang, Jiangyang, Dyrby, Tim B, Johnson, G Allan, Cohen-Adad, Julien, Budde, Matthew D, and Jelescu, Ileana O

Subjects
FOS: Biological sciences, FOS: Physical sciences, Quantitative Biology - Tissues and Organs, Medical Physics (physics.med-ph), Tissues and Organs (q-bio.TO), Physics - Medical Physics
Abstract

The value of preclinical diffusion MRI (dMRI) is substantial. While dMRI enables in vivo non-invasive characterization of tissue, ex vivo dMRI is increasingly being used to probe tissue microstructure and brain connectivity. Ex vivo dMRI has several experimental advantages including higher signal-to-noise ratio and spatial resolution compared to in vivo studies, and more advanced diffusion contrasts for improved microstructure and connectivity characterization. Another major advantage is direct comparison with histological data as a crucial methodological validation. However, there are a number of considerations that must be made when performing ex vivo experiments. The steps from tissue preparation, image acquisition and processing, and interpretation of results are complex, with many decisions that not only differ dramatically from in vivo imaging, but ultimately affect what questions can be answered using the data. This work represents 'Part 2' of a series of recommendations and considerations for preclinical dMRI, where we focus on best practices for dMRI of ex vivo tissue. We first describe the value that ex vivo imaging adds to the field of dMRI, followed by general considerations and foundational knowledge that must be considered when designing experiments. We then give guidelines for ex vivo protocols, including tissue preparation, imaging sequences and data processing including pre-processing, model-fitting, and tractography. Finally, we provide an online resource which lists publicly available ex vivo dMRI datasets and dedicated software packages. In each section, we attempt to provide guidelines and recommendations, but also highlight areas for which no guidelines exist, and where future work should lie. An overarching goal herein is to enhance the rigor and reproducibility of ex vivo dMRI acquisitions and analyses, and thereby advance biomedical knowledge., Comment: 59 pages, 12 figures, part of ongoing efforts on ISMRM Diffusion Study Group initiative 'Best Practices (Consensus) for diffusion MRI'. arXiv admin note: text overlap with arXiv:2209.12994

Published
2022
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26. T1D‐weighted ihMT imaging – Part I. Isolation of long‐ and short‐T1D components by T1D‐filtering

Author

Hertanu, Andreea, primary, Soustelle, Lucas, additional, Le Troter, Arnaud, additional, Buron, Julie, additional, Le Priellec, Julie, additional, Carvalho, Victor N. D., additional, Cayre, Myriam, additional, Durbec, Pascale, additional, Varma, Gopal, additional, Alsop, David C., additional, Girard, Olivier M., additional, and Duhamel, Guillaume, additional

Published
2022
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27. A Motion Correction Strategy for Multi-Contrast based 3D parametric imaging: Application to Inhomogeneous Magnetization Transfer (ihMT)

Author

Jean-Philippe Ranjeva, Maxime Guye, Lucas Soustelle, Olivier M. Girard, Gopal Varma, Guillaume Duhamel, Jean Pelletier, Arnaud Le Troter, David C. Alsop, Andreea Hertanu, Julien Lamy, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - AP-HM] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE)-Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Harvard Medical School [Boston] (HMS), ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)- Hôpital de la Timone [CHU - APHM] (TIMONE), Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Duhamel, Guillaume, IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline - - verISMO2017 - ANR-17-CE18-0030 - AAPG2017 - VALID, and Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - APHM] (CEMEREM)

Subjects
Computer science, business.industry, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Image registration, Function (mathematics), Motion correction, 030218 nuclear medicine & medical imaging, Image (mathematics), 03 medical and health sciences, 0302 clinical medicine, [SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, Multi contrast, Parametric imaging, Computer vision, Magnetization transfer, Artificial intelligence, business, 030217 neurology & neurosurgery
Abstract

PurposeTo propose an efficient retrospective image-based method for motion correction of multi-contrast acquisitions with a low number of available images (MC-MoCo) and evaluate its use in 3D inhomogeneous Magnetization Transfer (ihMT) experiments in the human brain.MethodsA framework for motion correction, including image pre-processing enhancement and rigid registration to an iteratively improved target image, was developed. The proposed method was compared to Motion Correction with FMRIB’s Linear Image Registration Tool (MCFLIRT) function in FSL over 13 subjects. Native (pre-correction) and residual (post-correction) motions were evaluated by means of markers positioned at well-defined anatomical regions over each image.ResultsBoth motion correction strategies significantly reduced inter-image misalignment, and the MC-MoCo method yielded significantly better results than MCFLIRT.ConclusionMC-MoCo is a high-performance method for motion correction of multi-contrast volumes as in 3D ihMT imaging.

Published
2021

28. A strategy to reduce the sensitivity of inhomogeneous Magnetization Transfer (ihMT) imaging to radiofrequency transmit field variations at 3 T

Author

Maxime Guye, Thomas Troalen, Gopal Varma, Jean-Philippe Ranjeva, Andreea Hertanu, David C. Alsop, Guillaume Duhamel, Lucas Soustelle, Olivier M. Girard, Samira Mchinda, Centre de résonance magnétique biologique et médicale (CRMBM), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre d'Exploration Métabolique par Résonance Magnétique [Marseille] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE), Siemens Healthcare [France], Siemens AG [Munich], Beth Israel Deaconess Medical Center [Boston] (BIDMC), Harvard Medical School [Boston] (HMS), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Exploration Métabolique par Résonance Magnétique [Hôpital de la Timone - APHM] (CEMEREM), Hôpital de la Timone [CHU - APHM] (TIMONE)-Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017)

Subjects
Reproducibility, Materials science, Radio Waves, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Brain, Reproducibility of Results, Magnetic Resonance Imaging, White Matter, Healthy Volunteers, 030218 nuclear medicine & medical imaging, Computational physics, Power (physics), Root mean square, 03 medical and health sciences, 0302 clinical medicine, Humans, Radiology, Nuclear Medicine and imaging, Radio frequency, Magnetization transfer, Sensitivity (control systems), Saturation (chemistry), 030217 neurology & neurosurgery, Energy (signal processing)
Abstract

International audience; PurposeTo minimize the sensitivity of inhomogeneous magnetization transfer gradient-echo (ihMT-GRE) imaging to radiofrequency (RF) transmit field (urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0003) inhomogeneities at 3 T.MethodsThe ihMT-GRE sequence was optimized by varying the concentration of the RF saturation energy over time, obtained by increasing the saturation pulse power while extending the sequence repetition time (TR). Different protocols were tested using numerical simulations and human in vivo experiments in the brain white matter (WM) of healthy subjects at 3 T. The sensitivity of the ihMT ratio (ihMTR) to urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0004 variations was investigated by comparing measurements obtained at nominal transmitter adjustments and following a 20% global urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0005 drop. The resulting relative variations (δihMTR) were evaluated voxelwise as a function of the local urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0006 distribution. The reproducibility of the protocol providing minimal urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0007 bias was assessed in a test-retest experiment.ResultsIn line with simulations, ihMT-GRE experiments conducted at high concentration of the RF energy over time demonstrated strong reduction of the urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0008 inhomogeneity effects in the human WM. Under the optimal conditions of 350-ms TR and 3-µT root mean square (RMS) saturation power, 73% of all WM voxels presented δihMTR below 10%. Reproducibility analysis yielded a close-to-zero systematic bias (ΔihMTR = −0.081%) and a high correlation (ρ² = 0.977) between test and retest experiments.ConclusionConcentrating RF saturation energy in ihMT-GRE sequences mitigates the sensitivity of the ihMTR to urn:x-wiley:07403194:media:mrm29055:mrm29055-math-0009 variations and allows for clinical-ready ihMT imaging at 3 T. This feature is of particular interest for high and ultra-high field applications.

Published
2021
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29. T

Author

Andreea, Hertanu, Lucas, Soustelle, Julie, Buron, Julie, Le Priellec, Myriam, Cayre, Arnaud, Le Troter, Gopal, Varma, David C, Alsop, Pascale, Durbec, Olivier M, Girard, and Guillaume, Duhamel

Subjects
Image Processing, Computer-Assisted, Protons, Magnetic Resonance Imaging, White Matter, Myelin Sheath
Abstract

To investigate the long- and short-TThe 3D ihMT rapid gradient echo (ihMTRAGE) sequences with increasing switching times (Δt) were used to derive ihMT high-pass TThe higher contribution of long-TLong-T

Published
2021

31. THE FUTURE JOBS DEVELOPMENT WITHIN DISRUPTIVE TECHNOLOGIES EVOLUTION AND ORGANIZATIONAL CULTURE CHANGE

Author

Codrinleonard Hertanu

Abstract

The contemporary world changes rhythm has reached an unparalleled level, mostly triggered by the conversion of 'technology advance' into 'technology changeover'. Both the disruptive technologies evolution and the metamorphosis given by globalization to the organizational culture have brought many challenges for the future professions development. The prognoses regarding future have represented a constant concern for different social categories over the mankind history. In the contemporary world the forecast of the future is performed in order to meet the growing needs of both the public and private sector, within the extremely competitive global environment, using techniques ranging from mere assessments to multi-criterion computer-based prognoses. Due to the fact that the present world has the tendency to evolve at least exponential, even a ten-year long prognosis is fairly different than the present layout of the contemporary environment in order to bring about a significant study related to the future global outline. The development of the future jobs takes into account, on one hand the detailed diversity and specialization of the present occupations, on the other mostly refers to pinpointing those professions that even though do not exist at the present moment, they will be needed for running different organizations, systems and institutions of the future interconnected and highly technical world. In order to accomplish a high level accuracy assessment of the way in which the future occupations will evolve, we have to bring into discussion those variables that mostly influence the development trend of the nowadays world professions. An entire array of the present studies widely recognize that the progress of the new technologies and, especially of the disruptive ones, will pose one of the most meaningful impact over the way in which the present moment jobs will be transformed. At the present moment, different domains of the latest technologies have been regarded to have an impact, sufficient enough to trigger crucial mutations that irrevocably change the way in which the business environment operates, the consumers' behaviors, and the manner in which both goods and services are produced. While in previous - but still not so far - times these technological achievements had been represented by electricity and automobile as well as television, at the present moment the disruptive feature is retrieved mainly within Connectivity, Internet of Things (IoT) and Blockchain Technology. Importantly, all these evolutions from the technology domain will generate paramount and irrevocable mutations within the organizational culture of the whole types of future institutions. For future professions the fundamental shifts will be retrieved within the essential change of the occupations development paradigm, through moving the center of gravity from the institutional area to that of the employees. One of the main mutations regards the fact that not the corporations or institutions will primarily recruit their personnel, but conversely, the employees will be those to hire them. Besides, not the companies will mainly be the creators of the new types of professions, but the employees will do this. Last but not least, the chief dimension where the overarching events, transactions and social-economical phenomena are going to take place will not be that of the companies and institutions but that quite heterogeneous of the employees.

Published
2020
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32. Sustainability and Corporate Branding: shotgun wedding or match made in heaven?

Author

Morgans, Roosmarijn, Hertanu, Teodora, Morgans, Roosmarijn, and Hertanu, Teodora

Abstract

Purpose: The purpose of this thesis is to gain a better understanding of the interplay between sustainability and corporate branding internally in organisations. By studying how internal communication contributes to the employees’ perception of these concepts, we aspire for this research to result in a greater comprehension of the role of internal communication in relation to sustainability and corporate branding. Theoretical Perspective: The two main theoretical perspectives are the internal brand management theory by Burmann and Zeplin (2005) and stakeholder theory, developed by Freeman (1984). Based on an in- depth review of the existing literature and theory, a research framework has been developed to guide the study. Methodology: A qualitative multiple case study with an abductive approach was applied based on the research philosophy of social constructionism. The empirical data was collected through 15 in-depth interviews with employees from the companies Ørsted and Arla. The interviews were semi-structured allowing theoretically-based as well as empirically-led questions. The primary findings are complemented by secondary textual data. Findings: Sustainability and corporate branding are internally communicated through a mix of central, cascade and lateral communication. The employee perception of the integration of sustainability communication in brand communication depends on the organisation’s business format and implementation strategy. Our study established a positive connection between sustainability and brand commitment. The feeling of contributing to a bigger cause plays a role in this connection. Enabling relevant employee roles in the organisation's sustainability journey can increase the connection further. The integration of sustainability into the brand identity presents the opportunity for a strong corporate brand that lives up to the urgent societal demands. Contributions: By focusing on the role of internal communication in the connection betwe

Published
2021

33. A Motion Correction Strategy for Multi-Contrast based 3D parametric imaging: Application to Inhomogeneous Magnetization Transfer (ihMT)

Author

Soustelle, Lucas, primary, Lamy, Julien, additional, Le Troter, Arnaud, additional, Hertanu, Andreea, additional, Guye, Maxime, additional, Ranjeva, Jean-Philippe, additional, Varma, Gopal, additional, Alsop, David C., additional, Pelletier, Jean, additional, Girard, Olivier, additional, and Duhamel, Guillaume, additional

Published
2020
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35. T1D‐weighted ihMT imaging – Part II. Investigating the long‐ and short‐T1D components correlation with myelin content. Comparison with R1 and the macromolecular proton fraction.

Author

Hertanu, Andreea, Soustelle, Lucas, Buron, Julie, Le Priellec, Julie, Cayre, Myriam, Le Troter, Arnaud, Varma, Gopal, Alsop, David C., Durbec, Pascale, Girard, Olivier M., and Duhamel, Guillaume

Subjects
MYELIN, MAGNETIZATION transfer, HISTOLOGICAL techniques, PROTONS, REFERENCE values
Abstract

Purpose: To investigate the long‐ and short‐T1D components correlation with myelin content using inhomogeneous magnetization transfer (ihMT) high‐pass and band‐pass T1D‐filters and to compare ihMT, R1, and the macromolecular proton fraction (MPF) for myelin specific imaging. Methods: The 3D ihMT rapid gradient echo (ihMTRAGE) sequences with increasing switching times (Δt) were used to derive ihMT high‐pass T1D‐filters with increasing T1D cutoff values and an ihMT band‐pass T1D‐filter for components in the 100 µs to 1 ms range. 3D spoiled gradient echo quantitative MT (SPGR‐qMT) protocols were used to derive R1 and MPF maps. The specificity of R1, MPF, and ihMT T1D‐filters was evaluated by comparison with two histological reference techniques for myelin imaging. Results: The higher contribution of long‐T1Ds as compared to the short components as Δt got longer led to an increase in the specificity to myelination. In contrast, focusing on the signal originating from a narrow range of short‐T1Ds (< 1 ms) as isolated by the band‐pass T1D‐filter led to lower specificity. In addition, the significantly lower r2 correlation coefficient of the band‐pass T1D‐filter suggests that the origin of short‐T1D components is mostly associated with non‐myelin protons. Also, the important contribution of short‐T1Ds to the estimated MPF, explains its low specificity to myelination as compared to the ihMT high‐pass T1D‐filters. Conclusion: Long‐T1D components imaging by means of ihMT high‐pass T1D‐filters is proposed as an MRI biomarker for myelin content. Future studies should enable the investigation of the sensitivity of ihMT T1D‐filters for demyelinating processes. [ABSTRACT FROM AUTHOR]

Published
2022
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36. T1D‐weighted ihMT imaging – Part I. Isolation of long‐ and short‐T1D components by T1D‐filtering.

Author

Hertanu, Andreea, Soustelle, Lucas, Le Troter, Arnaud, Buron, Julie, Le Priellec, Julie, Carvalho, Victor N. D., Cayre, Myriam, Durbec, Pascale, Varma, Gopal, Alsop, David C., Girard, Olivier M., and Duhamel, Guillaume

Subjects
CENTRAL nervous system, MAGNETIZATION transfer, GRAY matter (Nerve tissue), NERVE tissue, WHITE matter (Nerve tissue)
Abstract

Purpose: To identify T1D‐filtering methods, which can specifically isolate various ranges of T1D components as they may be sensitive to different microstructural properties. Methods: Modified Bloch‐Provotorov equations describing a bi‐T1D component biophysical model were used to simulate the inhomogeneous magnetization transfer (ihMT) signal from ihMTRAGE sequences at high RF power and low duty‐cycle with different switching time values for the dual saturation experiment: Δt = 0.0, 0.8, 1.6, and 3.2 ms. Simulations were compared with experimental signals on the brain gray and white matter tissues of healthy mice at 7T. Results: The lengthening of Δt created ihMT high‐pass T1D‐filters, which efficiently eliminated the signal from T1D components shorter than 1 ms, while partially attenuating that of longer components (≥ 1 ms). Subtraction of ihMTR images obtained with Δt = 0.0 ms and Δt = 0.8 ms generated a new ihMT band‐pass T1D‐filter isolating short‐T1D components in the 100‐µs to 1‐ms range. Simulated ihMTR values in central nervous system tissues were confirmed experimentally. Conclusion: Long‐ and short‐T1D components were successfully isolated with high RF power and low duty‐cycle ihMT filters in the healthy mouse brain. Future studies should investigate the various T1D‐range microstructural correlations in in vivo tissues. [ABSTRACT FROM AUTHOR]

Published
2022
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37. MRI assessment of multiple dipolar relaxation time ( T 1 D ) components in biological tissues interpreted with a generalized inhomogeneous magnetization transfer (ihMT) model

Author

Carvalho, Victor N.D., Hertanu, Andreea, Grélard, Axelle, Mchinda, Samira, Soustelle, Lucas, Loquet, Antoine, Dufourc, Erick J., Varma, Gopal, Alsop, David C., Thureau, Pierre, Girard, Olivier M., Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), Université de Bordeaux (UB)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), ANR-17-CE18-0030,verISMO,IRM du transfert d'aimantation inhomogène : vers un nouveau biomarqueur in vivo spécifique et sensible de la myéline(2017), European Project: 713750,H2020,H2020-MSCA-COFUND-2015,DOC2AMU(2016), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
T 1D, MRI contrast, Myelin, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Jeener-Broekaert, Dipolar relaxation time, Inhomogeneous magnetization transfer, Myelin Imaging, ihMT
Abstract

International audience; T 1D , the relaxation time of dipolar order, is sensitive to slow motional processes. Thus T 1D is a probe for membrane dynamics and organization that could be used to characterize myelin, the lipid-rich membrane of axonal fibers. A mono-component T 1D model associated with a modified ihMT sequence was previously proposed for in vivo evaluation of T 1D with MRI. However, experiments have suggested that myelinated tissues exhibit multiple T 1D components probably due to a heterogeneous molecular mobility. A bi-component T 1D model is proposed and implemented. ihMT images of ex-vivo, fixed rat spinal cord were acquired with multiple frequency alternation rate. Fits to data yielded two T 1D s of about 500 µs and 10 ms. The proposed model seems to further explore the complexity of myelin organization compared to the previously reported mono-component T 1D model.

Published
2020
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38. Evaluation of Inhomogeneous Magnetization Transfer ihMT at 9.4T for the visualization of the Purkinje Network in the heart

Author

haliot, Kylian, Hertanu, Andreea, Girard, Olivier, Soustelle, Lucas, Duhamel, Guillaume, Magat, Julie, Quesson, Bruno, Duhamel, Guillaume, IHU-LIRYC, CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), IHU lyric, and Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux]

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2020

39. Multi-T1D weighting ihMT imaging in the Cuprizone mouse model

Author

Hertanu, Andreea, Soustelle, Lucas, Troter, Arnaud Le, Buron, Julie, Carvalho, Victor, Cayre, Myriam, Durbec, Pascale, Varma, Gopal, Alsop, David, Girard, Olivier, Duhamel, Guillaume, Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, and Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2020

40. MRI assessment of multiple dipolar relaxation time (T

Author

Victor N D, Carvalho, Andreea, Hertanu, Axelle, Grélard, Samira, Mchinda, Lucas, Soustelle, Antoine, Loquet, Erick J, Dufourc, Gopal, Varma, David C, Alsop, Pierre, Thureau, Olivier M, Girard, and Guillaume, Duhamel

Subjects
Spinal Cord, Radio Waves, Cell Membrane, Image Processing, Computer-Assisted, Animals, Gray Matter, Models, Theoretical, Magnetic Resonance Imaging, White Matter, Algorithms, Axons, Myelin Sheath, Rats
Abstract

T

Published
2019

41. Multicomponent dipolar relaxation time (T1D) assessment in myelin using inhmogeneous magnetization transfer (ihMT) MRI

Author

Carvalho, Victor, Girard, Olivier M., Hertanu, Andreea, Soustelle, Lucas, Grélard, Axelle, Loquet, Antoine, Dufourc, Erick J., Varma, Gopal, Alsop, David C., Thureau, Pierre, Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), Université de Bordeaux (UB)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Duhamel, Guillaume, Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

42. On the dipolar order underlying broad macromolecular lines

Author

Girard, Olivier M., Carvalho, Victor, De Rochefort, Ludovic, Hertanu, Andreea, Thureau, Pierre, Varma, Gopal, Alsop, David C., Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Duhamel, Guillaume

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging
Abstract

International audience; Dipolar order has recently regained attention in MRI to analyze dipolar broadened lines in CEST and inhomogeneous Magnetization Transfer (ihMT), leading to new frequency irradiation patterns for enhanced saturation and access to an unexplored degree of freedom. A better understanding of dipolar order is of great interest to guide intuition and may lead to fundamental optimization of the ihMT technique, which is a promising tool providing new tissue contrasts. In this contribution we propose to review this concept, considering a simplified model of isolated proton pairs and the general Provotorov theory of RF saturation which applies to an ensemble of coupled spin.

Published
2019

43. Assessment of two T1D components within myelinated tissue with ihMT MRI

Author

Carvalho, Victor, Girard, Olivier M., Hertanu, Andreea, Mchinda, Samira, Soustelle, Lucas, Grélard, Axelle, Loquet, Antoine, Dufourc, Erick J., Varma, Gopal, Alsop, David C., Thureau, Pierre, Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), Université de Bordeaux (UB)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), and Duhamel, Guillaume

Subjects
endocrine system, [SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, endocrine system diseases, immune system diseases, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, nutritional and metabolic diseases
Abstract

International audience; T1D, the relaxation time of the dipolar order, is a probe for membrane dynamics and organization that could be used to assess myelin integrity. A single-component T1D model associated with a modified ihMT sequence had been proposed for in vivo evaluation of T1D with MRI. However, experiments and simulations revealed that myelinated tissues exhibit multiple T1D components. A bi-component T1D model is proposed and validated. Fits in a rat spinal cord yield two T1Ds of about 10 ms and 400 μs. The results suggest that myelin has a dynamically heterogeneous organization.

Published
2019

44. Toward quantitative inhomogeneous magnetization transfer (qihMT) using a general Matrix Exponential Model

Author

Hertanu, Andreea, Girard, Olivier M., Carvalho, Victor, Soustelle, Lucas, Varma, Gopal, Alsop, David C., Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, and Duhamel, Guillaume

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging
Abstract

International audience; Inhomogeneous magnetization transfer is becoming an important tool in the detection of demyelinating pathologies, as well as in the understanding of the molecular mechanisms engaged in demyelinating/remyelinating processes. Although ihMT ratio delivers a reproducible index sensitive to the dipolar order underpinning the ihMT effect, advanced approaches analogous to quantitative MT could allow estimation of quantitative parameters directly related to the underlying biophysical model of myelin. This study proposes a general framework based on the Matrix Exponential Model allowing fast fitting of ihMT data. Demonstration of qihMT is performed ex-vivo on rat spinal cord specimen and in-vivo on mouse brain.

Published
2019

45. Act of kindness: A study on modern day crisis handling and its effect on brand identity

Author

Hertanu, Teodora, Bertelsen, Mette Holm, Jeppesen, Mads Hüsig, Hertanu, Teodora, Bertelsen, Mette Holm, and Jeppesen, Mads Hüsig

Abstract

Purpose: This paper aims to explore and examine how companies have reacted to suddenly occurring crises in the 21st century. The paper will investigate how companies have adapted – or stayed in hiding – during the COVID-19 pandemic, and how this has impacted their corporate brand identity and their core values. The paper will introduce a new framework to be used for assessing the strategic approach for companies during hard times. Design/Methodology/Approach: The paper will consist of a literature review on the topic, as well as case studies on several companies who have positively or negatively adapted their offerings as a response to the Coronavirus crisis. These companies have taken an aggressive, adaptive, or innovative approach to crisis handling, and this paper will investigate the different approaches and their effect on the core values of their brand. Findings: This paper presents a new framework for companies to decide which strategic approach to follow when a global crisis hits. Through case studies it is clear that companies cannot rely on their regular CSR policy, as a global crisis goes way beyond that. The brand core can be extended in three different ways; the innovative approach, the aggressive approach or the adaptive approach. This paper also finds that the last approach, the passive, should only be used when a company is not directly affected negatively by an ongoing crisis. Research limitations/future research: One key limitation of this paper is that only a selected number of cases have been analysed. Further, it should be noted that the analysis has been done from an outside-in perspective, and for further research an inside-out perspective should also be considered. A different methodology can also be followed, by using media coverage and / or by interviewing former executives. Theoretical implications: The paper introduces a new theoretical framework, which is tested on the COVID-19 crisis, but further analysis should be done on other crisis, Purpose: This paper aims to explore and examine how companies have reacted to suddenly occurring crises in the 21st century. The paper will investigate how companies have adapted – or stayed in hiding – during the COVID-19 pandemic, and how this has impacted their corporate brand identity and their core values. The paper will introduce a new framework to be used for assessing the strategic approach for companies during hard times.

Published
2020

46. A strategy to reduce the sensitivity of inhomogeneous magnetization transfer (ihMT) imaging to radiofrequency transmit field variations at 3 T.

Author

Soustelle, Lucas, Troalen, Thomas, Hertanu, Andreea, Mchinda, Samira, Ranjeva, Jean‐Philippe, Guye, Maxime, Varma, Gopal, Alsop, David C., Duhamel, Guillaume, and Girard, Olivier M.

Subjects
MAGNETIZATION transfer, RADIO frequency, ROOT-mean-squares, WHITE matter (Nerve tissue)
Abstract

Purpose: To minimize the sensitivity of inhomogeneous magnetization transfer gradient‐echo (ihMT‐GRE) imaging to radiofrequency (RF) transmit field (B1+) inhomogeneities at 3 T. Methods: The ihMT‐GRE sequence was optimized by varying the concentration of the RF saturation energy over time, obtained by increasing the saturation pulse power while extending the sequence repetition time (TR). Different protocols were tested using numerical simulations and human in vivo experiments in the brain white matter (WM) of healthy subjects at 3 T. The sensitivity of the ihMT ratio (ihMTR) to B1+ variations was investigated by comparing measurements obtained at nominal transmitter adjustments and following a 20% global B1+ drop. The resulting relative variations (δihMTR) were evaluated voxelwise as a function of the local B1+ distribution. The reproducibility of the protocol providing minimal B1+ bias was assessed in a test‐retest experiment. Results: In line with simulations, ihMT‐GRE experiments conducted at high concentration of the RF energy over time demonstrated strong reduction of the B1+ inhomogeneity effects in the human WM. Under the optimal conditions of 350‐ms TR and 3‐µT root mean square (RMS) saturation power, 73% of all WM voxels presented δihMTR below 10%. Reproducibility analysis yielded a close‐to‐zero systematic bias (ΔihMTR = −0.081%) and a high correlation (ρ² = 0.977) between test and retest experiments. Conclusion: Concentrating RF saturation energy in ihMT‐GRE sequences mitigates the sensitivity of the ihMTR to B1+ variations and allows for clinical‐ready ihMT imaging at 3 T. This feature is of particular interest for high and ultra‐high field applications. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
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47. Modèle exponential matriciel general pour la quantification des paramètres biophysiques tissulaires par transfert d’aimantation inhomogène (ihMT)

Author

Hertanu, Andreea, Girard, Olivier M., Carvalho, Victor, Soustelle, Lucas, Varma, Gopal, Alsop, David C., Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, and Duhamel, Guillaume

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2019

48. Caractérisation par transfert d’aimantation inhomogène (ihMT) du réseau de Purkinje dans le cœur par IRM à 7 Teslas

Author

haliot, Kylian, Hertanu, Andreea, Girard, Olivier M., Duhamel, Guillaume, Magat, Julie, Quesson, Bruno, IHU lyric, Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), and Duhamel, Guillaume

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2019

49. Mesure de deux composantes T1D dans les tissus myélinisés par IRM ihMT

Author

Carvalho, Victor, Girard, Olivier M., Hertanu, Andreea, Mchinda, Samira, Soustelle, Lucas, Grélard, Axelle, Loquet, Antoine, Dufourc, Erick J., Varma, Gopal, Alsop, David C., Thureau, Pierre, Duhamel, Guillaume, Centre de résonance magnétique biologique et médicale (CRMBM), Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Beth Israel Deaconess - Harvard Medical School, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Duhamel, Guillaume, Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, [INFO.INFO-IM] Computer Science [cs]/Medical Imaging, [INFO.INFO-IM]Computer Science [cs]/Medical Imaging, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2019

50. Correlated Color Temperature Measuring and Adjustment System

Author

Radu Hertanu, Cristian-Gyozo Haba, Liviu Breniuc, Daniel Petrisor, and Catalin Daniel Galatanu

Subjects
Materials science, business.industry, 020209 energy, 020208 electrical & electronic engineering, 02 engineering and technology, Color temperature, Temperature measurement, law.invention, Optics, law, Dispersion (optics), 0202 electrical engineering, electronic engineering, information engineering, Calibration, Range (statistics), business, Light-emitting diode
Abstract

This paper will present a Correlated Color Temperature (CCT) measurement and adjustment system. The system allows the fixing of a CCT and the control of lighting fixtures so that they emit light corresponding to the prescribed CCT. Lighting fixtures, even if they are made by the same manufacturer, may have different characteristics, for example due to the technological dispersion of the parameters or the aging of the elements that generate light (eg LEDs). Using the system described in this paper, CCT can be adjusted in the range 2900K ÷ 6300K with an error of less than ± 25K for different levels of illumination.

Published
2019
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