Deformation Analysis to Detect and Quantify Active Lesions in 3D Medical Image Sequences

Evaluating precisely the temporal variations of tumor volumes is very important for at least three types of practical applications: pharmaceutical trials, decision making for drug treatment or surgery and patients follow-up. In this paper, we present a volumetric analysis technique, combining precise rigid registration of 3D medical images, non-rigid deformation computation and flow field analysis. Our analysis technique has two outcomes: the detection of evolving lesions and the quantitative measurement of volume variations. The originality of our approach is that no precise} segmentation of the lesion is needed but the approximative designation of a region of interest, which can be automatized. We distinguish between tissue transformation (image intensity changes without deformation) and expansion or contraction effects reflecting a change of mass within the tissue; a real lesion being generally the combination of both effects. The method is tested with synthesized 3D image sequences and applied, in a first attempt to quantify in-vivo a mass effect, to the analysis of a real patient case with Multiple Sclerosis

Calcul de variations de volume de lésions dans des images médicales tridimensionnelles

L'évaluation précise de la variation temporelle du volume d'une lésion est très importante pour diverses applications : recherche pharmaceutique et médicale, suivi des patients, prise de décision thérapeutique. Dans cet article, nous décrivons un modèle de croissance de lésions, qui nous sert à valider une technique originale de mesure de variation de volume. Dans un premier temps nous effectuons un recalage rigide des images, ensuite nous calculons le champ des déformations résiduelles que nous intégrons sur des surfaces emboîtées épousant la forme de la structure évolutive. Le maximum du profil obtenu correspond à la variation de volume cherchée dans le cas synthétique et conduit à des valeurs cohérentes avec l'intuition dans le cas d'un patient atteint de sclérose en plaques

Deformation Analysis to Detect and Quantify Active Lesions in Three-Dimensional Medical Image Sequences

International audienceAbstract--Evaluating precisely the temporal variations of lesion volumes is very important for at least three types of practical applications: pharmaceutical trials, decision making for drug treatment or surgery, and patient follow-up. In this paper we present a volumetric analysis technique, combining precise rigid registration of three-dimensional (3-D) (volumetric) medical images, nonrigid deformation computation, and flow-field analysis. Our analysis technique has two outcomes: the detection of evolving lesions and the quantitative measurement of volume variations. The originality of our approach is that no precise segmentation of the lesion is needed but the approximative designation of a region of interest (ROI) which can be automated. We distinguish between tissue transformation (image intensity changes without deformation) and expansion or contraction effects reflecting a change of mass within the tissue. A real lesion is generally the combination of both effects. The method is tested with synthesized volumetric image sequences and applied, in a first attempt to quantify in vivo a mass effect, to the analysis of a real patient case with multiple sclerosis (MS)

Detailed plan for the COMET WP3 initial research activity - list of research projects and goals, participants and timing

Detailed plan for the COMET Work Package (WP) 3

Tritium and 14 C background levels in pristine aquatic systems and their potential sources of variability

C Aquatic systems Background levels Global fallout Regional scale a b s t r a c t Tritium and 14 C are currently the two main radionuclides discharged by nuclear industry. Tritium integrates into and closely follows the water cycle and, as shown recently the carbon cycle, as does 14 C (Eyrolle-Boyer et al., 2014a, b). As a result, these two elements persist in both terrestrial and aquatic environments according to the recycling rates of organic matter. Although on average the organically bound tritium (OBT) activity of sediments in pristine rivers does not significantly differ today (2007 e2012) from the mean tritiated water (HTO) content on record for rainwater (2.4 ± 0.6 Bq/L and 1.6 ± 0.4 Bq/L, respectively), regional differences are expected depending on the biomass inventories affected by atmospheric global fallout from nuclear testing and the recycling rate of organic matter within watersheds. The results obtained between 2007 and 2012 for 14 C show that the levels varied between 94.5 ± 1.5 and 234 ± 2.7 Bq/kg of C for the sediments in French rivers and across a slightly higher range of 199 ± 1.3 to 238 ± 3.1 Bq/kg of C for fish. This variation is most probably due to preferential uptake of some organic carbon compounds by fish restraining 14 C dilution with refractory organic carbon and/or with old carbonates both depleted in 14 C. Overall, most of these ranges of values are below the mean baseline value for the terrestrial environment (232.0 ± 1.8 Bq/kg of C in 2012, Roussel-Debet, 2014a) in relation to dilution by the carbonates and/or fossil organic carbon present in aquatic systems. This emphasises yet again the value of establishing regional baseline value ranges for these two radionuclides in order to account for palaeoclimatic and lithological variations. Besides, our results obtained from sedimentary archive investigation have confirmed the delayed contamination of aquatic sediments by tritium from the past nuclear tests atmospheric fallout, as recently demonstrated from data chronicles (Eyrolle-Boyer et al., 2014a,b). Thus Sedimentary archives can be successfully used to reconstruct past 14 C and OBT levels. Additionally, sediment repositories potentially represent significant storages of OBT that may account for in case of further remobilisation. We finally show that floods can significantly affect the OBT and 14 C levels within suspended particles or sediments depending on the origin of particles reinforcing the need to acquire baseline value range at a regional scale

Figeac autrefois : Jean Lartigaut, Figeac

Calmon Philippe. Figeac autrefois : Jean Lartigaut, Figeac. In: Revue géographique des Pyrénées et du Sud-Ouest, tome 56, fascicule 1, 1985. pp. 119-121

Figeac autrefois : Jean Lartigaut, Figeac

Calmon Philippe. Figeac autrefois : Jean Lartigaut, Figeac. In: Revue géographique des Pyrénées et du Sud-Ouest, tome 56, fascicule 1, 1985. pp. 119-121