Francois Kauffmann - Academia.edu (original) (raw)
Papers by Francois Kauffmann
Scientific Reports, 2017
Quantitative imaging modalities for the analysis of hypoxia in brain tumors are lacking. The obje... more Quantitative imaging modalities for the analysis of hypoxia in brain tumors are lacking. The objective of this study was to generate absolute maps of tissue ptO2 from [18F]-FMISO images in glioblastoma and less aggressive glioma patients in order to quantitatively assess tumor hypoxia. An ancillary objective was to compare estimated ptO2 values to other biomarkers: perfusion weighted imaging (PWI) and tumor metabolism obtained from 1H-MR mono-voxel spectroscopy (MRS). Ten patients with glioblastoma (GBM) and three patients with less aggressive glioma (nGBM) were enrolled. All patients had [18F]-FMISO and multiparametric MRI (anatomic, PWI, MRS) scans. A non-linear regression was performed to generate ptO2 maps based on normal appearing gray (NAGM) and white matter (NAWM) for each patient. As expected, a marked [18F]-FMISO uptake was observed in GBM patients. The ptO2 based on patient specific calculations was notably low in this group (4.8 ± 1.9 mmHg, p < 0.001) compared to all o...
AJR. American journal of roentgenology, Jan 16, 2017
The objective of our study was to evaluate the diagnostic performance of qualitative 3-T proton M... more The objective of our study was to evaluate the diagnostic performance of qualitative 3-T proton MR spectroscopy ((1)H-MRS) for the characterization of musculoskeletal neoplasms. Proton MRS studies of 74 patients (76 lesions) with a histologically confirmed musculoskeletal neoplasm or neoplasms were prospectively included in this study. All studies were performed using a 3-T MRI scanner. Spectra were analyzed with conventional MRI software provided by the fabricant and with dedicated independent MRS software. Spectra were evaluated visually for the presence or absence of a choline peak at 3.2 ppm. The presence of a choline peak was considered indicative of malignancy. The influences of tumor origin and spectral quality on diagnostic performance were considered. Diagnostic performance was similar with both software used (κ = 0.97). Qualitative (1)H-MRS failed to differentiate benign from malignant bone tumors regardless of the application of quality criteria (best sensitivity and spec...
Journal of Cerebral Blood Flow & Metabolism, 2016
The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limite... more The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limited success. Our hypothesis is that the eventual benefits of carbogen depend on the capacity for vasodilation. We examined, with MRI, changes in fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in response to carbogen. The analyses were performed in two xenograft models of glioma (U87 and U251) recognized to have different vascular patterns. Carbogen increased fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in contralateral tissues. In the tumor core and peritumoral regions, changes were dependent on the capacity to vasodilate rather than on resting fractional cerebral blood volume. In the highly vascularised U87 tumor, carbogen induced a greater increase in fractional cerebral blood volume and blood oxygen saturation in comparison to the less vascularized U251 tumor. The blood ...
Journal of Neuroradiology, 2007
Journal of Physics: Conference Series, 2011
Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metaboli... more Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metabolism, mitochondrial function, lipid metabolism, necrosis and apoptosis, cell proliferation, and infiltration. These changes could be monitored longitudinally (every 4 months over 6 years) in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI) and spectroscopy (MRS) and MR perfusion. Some examples of early clinical data from longitudinal follow-up monitoring in humans of energy and glycolytic metabolism, lipid metabolism, necrosis, proliferation, and infiltration measured by conventional MRI, MRS and perfusion, and positron emission tomography (PET) are shown in glial brain tumors after therapy. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and therapeutic response.
Frontiers in Plant Science, 2015
Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding... more Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding crop, especially in the context of soil S oligotrophy. Therefore, predicting plant growth, S plant allocation (between the plant's compartments) and S pool partitioning (repartition of the mobileS vs. non-mobileS fractions) until the onset of reproductive phase could help in the diagnosis of S deficiencies during the early stages. For this purpose, a process-based model, SuMoToRI (Sulfur Model Toward Rapeseed Improvement), was developed up to the onset of pod formation. The key features rely on (i) the determination of the S requirements used for growth (structural and metabolic functions) through critical S dilution curves and (ii) the estimation of a mobile pool of S that is regenerated by daily S uptake and remobilization from senescing leaves. This study describes the functioning of the model and presents the model's calibration and evaluation. SuMoToRI was calibrated and evaluated with independent datasets from greenhouse experiments under contrasting S supply conditions. It is run with a small number of parameters with generic values, except in the case of the radiation use efficiency, which was shown to be modulated by S supply. The model gave satisfying predictions of the dynamics of growth, S allocation between compartments and S partitioning, such as the mobileS fraction in the leaves, which is an indicator of the remobilization potential toward growing sinks. The mechanistic features of SuMoToRI provide a process-based framework that has enabled the description of the S remobilizing process in a species characterized by senescence during the vegetative phase. We believe that this model structure could be useful for modeling S dynamics in other arable crops that have similar senescence-related characteristics.
Journal of Neuroradiology, 2005
[1991] Proceedings Computers in Cardiology
Heart Rate Variability (HRV) analysis of 24 healthy newborn sleeping babies was performed by Shor... more Heart Rate Variability (HRV) analysis of 24 healthy newborn sleeping babies was performed by Short-T i m e Fourier Transform in 3 frequency bands, reflecting the activity of both branches of the Autonomic Nervous System (ANS), vagal and sympathetic. The means of the 3 extracted time signals, computed over records of 512 heartbeats, were used as a material for principal component analysis, and for discriminant factor analyses, t o separate sleep states and conceptional age (C A) groups. This study suggests that: 1/ sleep state discrimination, on the basis of an opposition between high (purely vagal in its origin) and low (vagal and sympathetic) frequency HRV, is regularly improved from 31 t o 41 weeks C A , and 2/ a strong increase in A N S activity, mainly vagal, as reflected by high frequency HRV, occurs precociously, not later than 38 weeks C A. *Supported by grants RGR62 INSERM-CNAMTS and INSERM CJF8909 according to conceptional age (CA), maturation of the ANS, in both its components, vagal and sympathetic. This is done by studying: 1/ the differentiation between sleep states, as measured by HRV variables and 2/ the age-related modifications of these variables, from the pre-term to the full-term group.
Journal de Radiologie, 2006
Journal of Neuroradiology, 2006
Archives des maladies du coeur et des vaisseaux, 1989
To evidence abnormality of cardiac control by the autonomic nervous system in the sudden infant d... more To evidence abnormality of cardiac control by the autonomic nervous system in the sudden infant death syndrome (SIDS) we retrospectively analysed the Holter recordings and cardiopneumograms of 19 infants (11 boys, 8 girls) of mean +/- SD age 2.3 +/- 1.5 months who had subsequently died of SIDS. Two infants were regarded as normal and the reference diagnoses in the remaining 17 infants were: apparent life threatening event (8), SIDS siblings (8) and prematurity (1). At the time of death the age was 4.2 +/- 2 months. Each of these infants was matched with three control infants in term of postnatal age, gestational age and reference diagnosis, but without SIDS at follow-up of at least one year. Nine hours of Holter recordings (9 p.m. to 6 a.m.) were analysed in term of mean heart rate and sinus oscillations waves. To differentiate between short oscillations of 4 to 6 RR, which are induced by respiration and reflect vagal activity, and long oscillations of 20 to 32 RR, which reflect bot...
Journal de Radiologie, 2006
obtenir un contraste substance blanche-substance grise satisfaisant, sans inconvénient particulie... more obtenir un contraste substance blanche-substance grise satisfaisant, sans inconvénient particulier. La séquence FLAIR pondérée T2 à 3T fournit des détails anatomiques des noyaux gris centraux et du tronc cérébral inaccessibles à 1,5T. Cependant, elle manque de sensibilité dans certaines pathologies comme la sclérose en plaques où les lésions présentent souvent un signal moins brillant qu'à 1,ST. La séquence FLAIR T2 à 3T a été plusieurs fois prise en défaut dans le diagnostic d'hémorragie méningée alors que la séquence était franchement positive à 1,5T. Conclusion : Les performances de l'imagerie de diffusion sont nettement supérieures à 3T. Les images FLAIR pondérées T2 doivent être interprétées avec prudence en particulier en cas de suspicion d'hémorragie méningée. azi Mots clés : Système nerveux, technique d'exploration Durée : 8 minutes EXPLORATION DES VAISSEAUX CEREBRAUX A 3T B CARSIN-NICOL JC FERRÉ, M CARSIN RENNES-FRANCE Résumé : L'angiographie IRM est devenue une séquence de choix dans l'exploration des pathologies encéphaliques. Associé à l'imagerie parallèle, le 3 Tesla permet d'obtenir une amélioration des images dans chaque technique en raison essentiellement d'un meilleur rapport signal sur bruit. Ainsi, la résolution spatiale peut être accrue, sans augmentation de la durée des acquisitions en Time of Flight, avec une meilleure visualisation des vaisseaux en distalité. Le contraste de phase 3D devient plus accessible, car plus rapide. En ARM avec injection de gadolinium, la dose de produit de contraste injectée est moindre d'environ 113 par rapport à celle utilisée à 1,s Tesla. L'ARM dynamique bénéficie d'une amélioration de la résolution spatiale mais aussi temporelle, avec une acquisition 3D unique et un débit d'injection moins élevé qu'à 1,s Tesla, soit à 3 d s .
Journal de Radiologie, 2007
teux intermédiaire, diminution de hauteur rénale intermédiaire et élargissement intermédiaire du ... more teux intermédiaire, diminution de hauteur rénale intermédiaire et élargissement intermédiaire du diamètre pyélique. Les lésions histologiques avaient également un phénotype intermédiaire: atrophie, apoptose, infiltration leucocytaire et fibrose. Dans le groupe obstruction partielle, la perte de hauteur du rein obstrué était significativement corrélée au degré d'apoptose. Conclusion: Dans ce nouveau modèle d'obstruction partielle néonatale, des lésions spécifiques intermédiaires entre obstruction complète et rein normal ont pu être mesurées en IRM et en histologie. Des souris Kü pour différents facteurs intervenant dans la pathogènèse des lésions rénales obstructives pourront être étudiées.
Journal de Radiologie, 2005
Objectifs Determiner en SRM cerebrale (1H, simple volume, court TE) les variations spectrales en ... more Objectifs Determiner en SRM cerebrale (1H, simple volume, court TE) les variations spectrales en fonction de la region anatomique, du type tissulaire ou de modalites instrumentales chez 76 volontaires sains. Materiels et methodes IRM : 2D sagittales et axiales 3D T1 et 2D T2. SRM : 1H, volume de 7 a 12 cm3, STEAM (TE 30 ms) sur 2 appareils 1.5 T (GEMS) chez 76 VS (de 20 a 74 ans) dans 7 regions anatomiques. Traitements des donnees : logiciel SA/GE. Analyse statistique : comparaison de moyennes ; Analyse Factorielle de Correspondance (AFC) et Classification Ascendante Hierarchique (CAH) de groupes homogenes de profils spectraux. Resultats La variabilite fonction du type tissulaire est plus elevee que la variabilite regionale, notamment pour la Choline et le N-Acetyl-Aspartate (NAA). Certaines regions et certains metabolites (comme le NAA ou la Creatine) sont moins variables. L’AFC et la CAH separent 6 groupes homogenes de profils spectraux. La relation de chacun de ces profils avec des parametres instrumentaux et des regions anatomiques fut etudiee. Conclusion L’importance des fluctuations dues aux differences instrumentales, regionales et individuelles est essentielle a considerer pour augmenter la sensibilite et comparer ces variations a celles de processus pathologiques.
Proceedings. Computers in Cardiology 1988
ABSTRACT
Journal de Radiologie, 2008
ABSTRACT Objectifs Déterminer les variations cérébrales IRM et SRM d’aire, d’amplitude, de ratios... more ABSTRACT Objectifs Déterminer les variations cérébrales IRM et SRM d’aire, d’amplitude, de ratios ou de profil spectral de métabolite lors du suivi longitudinal de 3 ans de 21 patients atteints de tumeur oligodendro-gliale (12) ou de gliomatose (9) traitées par Témodal. Matériels et méthodes IRM : Sagittal Tl, axial rhô, T2, FLAIR, diffusion, 3D Tl puis 3 plans Gadolinium. SRM : 1H, simple volume à 1,5 T (GEMS), PRESS à multiple TE ; logiciel SA/GE et traitement développé localement calculant amplitudes, aires, ratios, et concentrations relatives. Analyse statistique : longitudinale des données spectroscopiques (tous les 4 mois sur 24 mois). Résultats Etudes quantitatives en IRM par segmentation multi-spectrale avec fusion en cours tout comme l’analyse des différences spectrales entre les groupes. Sans chimiothérapie, les profils spectroscopiques s’aggravent avec augmentation des ratios Choline et Myoinositol/Créatine et lactate, diminution du NAA/Cr. Sous traitement, le volume tumoral évolue peu entre examens tandis que les mesures spectroscopiques varient plus. Conclusion La SRM lors du suivi de tumeurs gliales traitées possède une grande variabilité mais la répétition des mesures la diminue et améliore l’évaluation pronostique. Avec des mesures TEP méthio-nine et de perfusion, cette approche multimodale évalue mieux les réponses thérapeutiques chimiothérapiques et antiangiogéniques.
Journal of Neuroradiology, 2008
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Describes a method to assess heart rate variations related to body movements. Digital signal proc... more Describes a method to assess heart rate variations related to body movements. Digital signal processing and a non-linear model are used. Preliminary results show that in both AS and QS the heart rate acceleration related to movements is higher in full-term than in premature infants. At a given age, the authors observe a tendency of higher acceleration in quiet sleep
Scientific Reports, 2017
Quantitative imaging modalities for the analysis of hypoxia in brain tumors are lacking. The obje... more Quantitative imaging modalities for the analysis of hypoxia in brain tumors are lacking. The objective of this study was to generate absolute maps of tissue ptO2 from [18F]-FMISO images in glioblastoma and less aggressive glioma patients in order to quantitatively assess tumor hypoxia. An ancillary objective was to compare estimated ptO2 values to other biomarkers: perfusion weighted imaging (PWI) and tumor metabolism obtained from 1H-MR mono-voxel spectroscopy (MRS). Ten patients with glioblastoma (GBM) and three patients with less aggressive glioma (nGBM) were enrolled. All patients had [18F]-FMISO and multiparametric MRI (anatomic, PWI, MRS) scans. A non-linear regression was performed to generate ptO2 maps based on normal appearing gray (NAGM) and white matter (NAWM) for each patient. As expected, a marked [18F]-FMISO uptake was observed in GBM patients. The ptO2 based on patient specific calculations was notably low in this group (4.8 ± 1.9 mmHg, p < 0.001) compared to all o...
AJR. American journal of roentgenology, Jan 16, 2017
The objective of our study was to evaluate the diagnostic performance of qualitative 3-T proton M... more The objective of our study was to evaluate the diagnostic performance of qualitative 3-T proton MR spectroscopy ((1)H-MRS) for the characterization of musculoskeletal neoplasms. Proton MRS studies of 74 patients (76 lesions) with a histologically confirmed musculoskeletal neoplasm or neoplasms were prospectively included in this study. All studies were performed using a 3-T MRI scanner. Spectra were analyzed with conventional MRI software provided by the fabricant and with dedicated independent MRS software. Spectra were evaluated visually for the presence or absence of a choline peak at 3.2 ppm. The presence of a choline peak was considered indicative of malignancy. The influences of tumor origin and spectral quality on diagnostic performance were considered. Diagnostic performance was similar with both software used (κ = 0.97). Qualitative (1)H-MRS failed to differentiate benign from malignant bone tumors regardless of the application of quality criteria (best sensitivity and spec...
Journal of Cerebral Blood Flow & Metabolism, 2016
The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limite... more The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limited success. Our hypothesis is that the eventual benefits of carbogen depend on the capacity for vasodilation. We examined, with MRI, changes in fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in response to carbogen. The analyses were performed in two xenograft models of glioma (U87 and U251) recognized to have different vascular patterns. Carbogen increased fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in contralateral tissues. In the tumor core and peritumoral regions, changes were dependent on the capacity to vasodilate rather than on resting fractional cerebral blood volume. In the highly vascularised U87 tumor, carbogen induced a greater increase in fractional cerebral blood volume and blood oxygen saturation in comparison to the less vascularized U251 tumor. The blood ...
Journal of Neuroradiology, 2007
Journal of Physics: Conference Series, 2011
Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metaboli... more Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metabolism, mitochondrial function, lipid metabolism, necrosis and apoptosis, cell proliferation, and infiltration. These changes could be monitored longitudinally (every 4 months over 6 years) in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI) and spectroscopy (MRS) and MR perfusion. Some examples of early clinical data from longitudinal follow-up monitoring in humans of energy and glycolytic metabolism, lipid metabolism, necrosis, proliferation, and infiltration measured by conventional MRI, MRS and perfusion, and positron emission tomography (PET) are shown in glial brain tumors after therapy. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and therapeutic response.
Frontiers in Plant Science, 2015
Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding... more Sulfur (S) nutrition in rapeseed (Brassica napus L.) is a major concern for this high S-demanding crop, especially in the context of soil S oligotrophy. Therefore, predicting plant growth, S plant allocation (between the plant's compartments) and S pool partitioning (repartition of the mobileS vs. non-mobileS fractions) until the onset of reproductive phase could help in the diagnosis of S deficiencies during the early stages. For this purpose, a process-based model, SuMoToRI (Sulfur Model Toward Rapeseed Improvement), was developed up to the onset of pod formation. The key features rely on (i) the determination of the S requirements used for growth (structural and metabolic functions) through critical S dilution curves and (ii) the estimation of a mobile pool of S that is regenerated by daily S uptake and remobilization from senescing leaves. This study describes the functioning of the model and presents the model's calibration and evaluation. SuMoToRI was calibrated and evaluated with independent datasets from greenhouse experiments under contrasting S supply conditions. It is run with a small number of parameters with generic values, except in the case of the radiation use efficiency, which was shown to be modulated by S supply. The model gave satisfying predictions of the dynamics of growth, S allocation between compartments and S partitioning, such as the mobileS fraction in the leaves, which is an indicator of the remobilization potential toward growing sinks. The mechanistic features of SuMoToRI provide a process-based framework that has enabled the description of the S remobilizing process in a species characterized by senescence during the vegetative phase. We believe that this model structure could be useful for modeling S dynamics in other arable crops that have similar senescence-related characteristics.
Journal of Neuroradiology, 2005
[1991] Proceedings Computers in Cardiology
Heart Rate Variability (HRV) analysis of 24 healthy newborn sleeping babies was performed by Shor... more Heart Rate Variability (HRV) analysis of 24 healthy newborn sleeping babies was performed by Short-T i m e Fourier Transform in 3 frequency bands, reflecting the activity of both branches of the Autonomic Nervous System (ANS), vagal and sympathetic. The means of the 3 extracted time signals, computed over records of 512 heartbeats, were used as a material for principal component analysis, and for discriminant factor analyses, t o separate sleep states and conceptional age (C A) groups. This study suggests that: 1/ sleep state discrimination, on the basis of an opposition between high (purely vagal in its origin) and low (vagal and sympathetic) frequency HRV, is regularly improved from 31 t o 41 weeks C A , and 2/ a strong increase in A N S activity, mainly vagal, as reflected by high frequency HRV, occurs precociously, not later than 38 weeks C A. *Supported by grants RGR62 INSERM-CNAMTS and INSERM CJF8909 according to conceptional age (CA), maturation of the ANS, in both its components, vagal and sympathetic. This is done by studying: 1/ the differentiation between sleep states, as measured by HRV variables and 2/ the age-related modifications of these variables, from the pre-term to the full-term group.
Journal de Radiologie, 2006
Journal of Neuroradiology, 2006
Archives des maladies du coeur et des vaisseaux, 1989
To evidence abnormality of cardiac control by the autonomic nervous system in the sudden infant d... more To evidence abnormality of cardiac control by the autonomic nervous system in the sudden infant death syndrome (SIDS) we retrospectively analysed the Holter recordings and cardiopneumograms of 19 infants (11 boys, 8 girls) of mean +/- SD age 2.3 +/- 1.5 months who had subsequently died of SIDS. Two infants were regarded as normal and the reference diagnoses in the remaining 17 infants were: apparent life threatening event (8), SIDS siblings (8) and prematurity (1). At the time of death the age was 4.2 +/- 2 months. Each of these infants was matched with three control infants in term of postnatal age, gestational age and reference diagnosis, but without SIDS at follow-up of at least one year. Nine hours of Holter recordings (9 p.m. to 6 a.m.) were analysed in term of mean heart rate and sinus oscillations waves. To differentiate between short oscillations of 4 to 6 RR, which are induced by respiration and reflect vagal activity, and long oscillations of 20 to 32 RR, which reflect bot...
Journal de Radiologie, 2006
obtenir un contraste substance blanche-substance grise satisfaisant, sans inconvénient particulie... more obtenir un contraste substance blanche-substance grise satisfaisant, sans inconvénient particulier. La séquence FLAIR pondérée T2 à 3T fournit des détails anatomiques des noyaux gris centraux et du tronc cérébral inaccessibles à 1,5T. Cependant, elle manque de sensibilité dans certaines pathologies comme la sclérose en plaques où les lésions présentent souvent un signal moins brillant qu'à 1,ST. La séquence FLAIR T2 à 3T a été plusieurs fois prise en défaut dans le diagnostic d'hémorragie méningée alors que la séquence était franchement positive à 1,5T. Conclusion : Les performances de l'imagerie de diffusion sont nettement supérieures à 3T. Les images FLAIR pondérées T2 doivent être interprétées avec prudence en particulier en cas de suspicion d'hémorragie méningée. azi Mots clés : Système nerveux, technique d'exploration Durée : 8 minutes EXPLORATION DES VAISSEAUX CEREBRAUX A 3T B CARSIN-NICOL JC FERRÉ, M CARSIN RENNES-FRANCE Résumé : L'angiographie IRM est devenue une séquence de choix dans l'exploration des pathologies encéphaliques. Associé à l'imagerie parallèle, le 3 Tesla permet d'obtenir une amélioration des images dans chaque technique en raison essentiellement d'un meilleur rapport signal sur bruit. Ainsi, la résolution spatiale peut être accrue, sans augmentation de la durée des acquisitions en Time of Flight, avec une meilleure visualisation des vaisseaux en distalité. Le contraste de phase 3D devient plus accessible, car plus rapide. En ARM avec injection de gadolinium, la dose de produit de contraste injectée est moindre d'environ 113 par rapport à celle utilisée à 1,s Tesla. L'ARM dynamique bénéficie d'une amélioration de la résolution spatiale mais aussi temporelle, avec une acquisition 3D unique et un débit d'injection moins élevé qu'à 1,s Tesla, soit à 3 d s .
Journal de Radiologie, 2007
teux intermédiaire, diminution de hauteur rénale intermédiaire et élargissement intermédiaire du ... more teux intermédiaire, diminution de hauteur rénale intermédiaire et élargissement intermédiaire du diamètre pyélique. Les lésions histologiques avaient également un phénotype intermédiaire: atrophie, apoptose, infiltration leucocytaire et fibrose. Dans le groupe obstruction partielle, la perte de hauteur du rein obstrué était significativement corrélée au degré d'apoptose. Conclusion: Dans ce nouveau modèle d'obstruction partielle néonatale, des lésions spécifiques intermédiaires entre obstruction complète et rein normal ont pu être mesurées en IRM et en histologie. Des souris Kü pour différents facteurs intervenant dans la pathogènèse des lésions rénales obstructives pourront être étudiées.
Journal de Radiologie, 2005
Objectifs Determiner en SRM cerebrale (1H, simple volume, court TE) les variations spectrales en ... more Objectifs Determiner en SRM cerebrale (1H, simple volume, court TE) les variations spectrales en fonction de la region anatomique, du type tissulaire ou de modalites instrumentales chez 76 volontaires sains. Materiels et methodes IRM : 2D sagittales et axiales 3D T1 et 2D T2. SRM : 1H, volume de 7 a 12 cm3, STEAM (TE 30 ms) sur 2 appareils 1.5 T (GEMS) chez 76 VS (de 20 a 74 ans) dans 7 regions anatomiques. Traitements des donnees : logiciel SA/GE. Analyse statistique : comparaison de moyennes ; Analyse Factorielle de Correspondance (AFC) et Classification Ascendante Hierarchique (CAH) de groupes homogenes de profils spectraux. Resultats La variabilite fonction du type tissulaire est plus elevee que la variabilite regionale, notamment pour la Choline et le N-Acetyl-Aspartate (NAA). Certaines regions et certains metabolites (comme le NAA ou la Creatine) sont moins variables. L’AFC et la CAH separent 6 groupes homogenes de profils spectraux. La relation de chacun de ces profils avec des parametres instrumentaux et des regions anatomiques fut etudiee. Conclusion L’importance des fluctuations dues aux differences instrumentales, regionales et individuelles est essentielle a considerer pour augmenter la sensibilite et comparer ces variations a celles de processus pathologiques.
Proceedings. Computers in Cardiology 1988
ABSTRACT
Journal de Radiologie, 2008
ABSTRACT Objectifs Déterminer les variations cérébrales IRM et SRM d’aire, d’amplitude, de ratios... more ABSTRACT Objectifs Déterminer les variations cérébrales IRM et SRM d’aire, d’amplitude, de ratios ou de profil spectral de métabolite lors du suivi longitudinal de 3 ans de 21 patients atteints de tumeur oligodendro-gliale (12) ou de gliomatose (9) traitées par Témodal. Matériels et méthodes IRM : Sagittal Tl, axial rhô, T2, FLAIR, diffusion, 3D Tl puis 3 plans Gadolinium. SRM : 1H, simple volume à 1,5 T (GEMS), PRESS à multiple TE ; logiciel SA/GE et traitement développé localement calculant amplitudes, aires, ratios, et concentrations relatives. Analyse statistique : longitudinale des données spectroscopiques (tous les 4 mois sur 24 mois). Résultats Etudes quantitatives en IRM par segmentation multi-spectrale avec fusion en cours tout comme l’analyse des différences spectrales entre les groupes. Sans chimiothérapie, les profils spectroscopiques s’aggravent avec augmentation des ratios Choline et Myoinositol/Créatine et lactate, diminution du NAA/Cr. Sous traitement, le volume tumoral évolue peu entre examens tandis que les mesures spectroscopiques varient plus. Conclusion La SRM lors du suivi de tumeurs gliales traitées possède une grande variabilité mais la répétition des mesures la diminue et améliore l’évaluation pronostique. Avec des mesures TEP méthio-nine et de perfusion, cette approche multimodale évalue mieux les réponses thérapeutiques chimiothérapiques et antiangiogéniques.
Journal of Neuroradiology, 2008
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Describes a method to assess heart rate variations related to body movements. Digital signal proc... more Describes a method to assess heart rate variations related to body movements. Digital signal processing and a non-linear model are used. Preliminary results show that in both AS and QS the heart rate acceleration related to movements is higher in full-term than in premature infants. At a given age, the authors observe a tendency of higher acceleration in quiet sleep