Motion frozen 18F-FDG cardiac PET

BackgroundPET reconstruction incorporating spatially variant 3D Point Spread Function (PSF) improves contrast and image resolution. "Cardiac Motion Frozen" (CMF) processing eliminates the influence of cardiac motion in static summed images. We have evaluated the combined use of CMF- and PSF-based reconstruction for high-resolution cardiac PET.MethodsStatic and 16-bin ECG-gated images of 20 patients referred for (18)F-FDG myocardial viability scans were obtained on a Siemens Biograph-64. CMF was applied to the gated images reconstructed with PSF. Myocardium to blood contrast, maximum left ventricle (LV) counts to defect contrast, contrast-to-noise (CNR) and wall thickness with standard reconstruction (2D-AWOSEM), PSF, ED-gated PSF, and CMF-PSF were compared.ResultsThe measured wall thickness was 18.9 ± 5.2 mm for 2D-AWOSEM, 16.6 ± 4.5 mm for PSF, and 13.8 ± 3.9 mm for CMF-PSF reconstructed images (all P < .05). The CMF-PSF myocardium to blood and maximum LV counts to defect contrasts (5.7 ± 2.7, 10.0 ± 5.7) were higher than for 2D-AWOSEM (3.5 ± 1.4, 6.5 ± 3.1) and for PSF (3.9 ± 1.7, 7.7 ± 3.7) (CMF vs all other, P < .05). The CNR for CMF-PSF (26.3 ± 17.5) was comparable to PSF (29.1 ± 18.3), but higher than for ED-gated dataset (13.7 ± 8.8, P < .05).ConclusionCombined CMF-PSF reconstruction increased myocardium to blood contrast, maximum LV counts to defect contrast and maintained equivalent noise when compared to static summed 2D-AWOSEM and PSF reconstruction

Développement d'un simulateur de tomographes à émission de positions

La tomographie à émission de positons (TEP) est une technique d'imagerie fonctionnelle. Grâce au développement du FDG et grâce à ses très bonnes sensibilité et résolution comparée aux gamma-caméras, la TEP s'est imposée en France et partout dans le monde comme un moyen d'investigation privilégié pour l'oncologie. C'est dans ce contexte que le LETI a souhaité reprendre son activité en TEP corps entier en lançant une phase de recherche concernant le développement de nouveaux matériaux de détection performants à l'énergie de référence du TEP. A cause des coûts associés au montage de prototypes, une phase de simulation a été décidée afin de fournir un outil qui permette de comparer les performances de différentes machines. Ce manuscrit présente l'ensemble des travaux réalisés avec logiciel de simulation, SimSET. La partie principale du travail de thèse a consisté en une étape de validation à partir de données obtenues avec d'autres simulateurs et sur les tomographes SIEMENS HR+ et ACCEL.The positron emission tomography (PET) is a functional imaging modality. Due to the development of the FDG and due to its good sensitivity and its good resolution compared with gamma-cameras, PET is widely used in oncology in France and over the world. In this context, LETI has restarted its activity in whole body PET and it has launched a research study concerning new detection materials efficient at PET energy. Because of the cost of prototypes, a simulation step has been decided to provide a tool to compare performances of different devices. This thesis book shows the works around the simulation software, SimSET. The main part of this work is the validation step from data obtained with others simulation softwares and from two physical tomographs.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Production of [C-11]Carbon Labelled Flumazenil and L-Deprenyl Using the iMiDEV (TM) Automated Microfluidic Radiosynthesizer

In the last decade, microfluidic techniques have been explored in radiochemistry, and some of them have been implemented in preclinical production. However, these are not suitable and reliable for preparing different types of radiotracers or dose-on-demand production. A fully automated iMiDEV (TM) microfluidic radiosynthesizer has been introduced and this study is aimed at using of the iMiDEV (TM) radiosynthesizer with a microfluidic cassette to produce [C-11]flumazenil and [C-11]L-deprenyl. These two are known PET radioligands for benzodiazepine receptors and monoamine oxidase-B (MAO-B), respectively. Methods were successfully developed to produce [C-11]flumazenil and [C-11]L-deprenyl using [C-11]methyl iodide and [C-11]methyl triflate, respectively. The final products 1644 +/- 504 MBq (n = 7) and 533 +/- 20 MBq (n = 3) of [C-11]flumazenil and [C-11]L-deprenyl were produced with radiochemical purities were over 98% and the molar activity for [C-11]flumazenil and [C-11]L-deprenyl was 1912 +/- 552 GBq/mu mol, and 1463 +/- 439 GBq/mu mol, respectively, at the end of synthesis. All the QC tests complied with the European Pharmacopeia. Different parameters, such as solvents, bases, methylating agents, precursor concentration, and different batches of cassettes, were explored to increase the radiochemical yield. Synthesis methods were developed using 3-5 times less precursor than conventional methods. The fully automated iMiDEV (TM) microfluidic radiosynthesizer was successfully applied to prepare [C-11]flumazenil and [C-11]L-deprenyl

Cross-sectional study to describe allergic rhinitis flare-ups and associated airways phenotype in house dust mite sensitization

Objectives To quantify and describe flare-ups of house dust mite allergic rhinitis (HDM-AR) which had occurred during the last 12 months in a population of adults and children candidate for Allergen ImmunoTherapy (AIT). Next, to identify associated clinical features. Materials and methods This was an observational, multicenter, cross-sectional study that included patients aged ≥ 5 years with HDM-AR eligible for AIT and without prior AIT for at least 12 months. Flare-ups were all period with impairment of quality of life (QoL) and requiring a change in their usual treatment. Data were collected using medical records and patient questionnaires. Variables associated with the occurrence of ≥ 2 AR flare-ups were identified. Results 1,701 patients were included (average age: 23 years, 51.5% males, 30.4% children, 17.7% adolescents and 51.9% adults). Severe and persistent AR affected 70.9% of them and 53.7% showed polysensitization. Asthma was associated with AR in 34.4% and was well-controlled in 58.5%. The occurrence of at least one AR flare-up in the year was reported by 77.7%, with an annual rate in the whole population of 2.6 ± 3.9 and a duration of 14.1 ± 17.1 days. Deeply or moderately AR-related degraded QoL was experienced by 39.5% and 64.6%, respectively. The occurrence of ≥ 2 AR flare-ups was reported by 54.5% and was associated with polysensitization, AR intermittence and severity. Conclusion AR flare-ups are frequent and impair QoL in HDM-allergic patients, suggesting that it could be considered as therapeutic targets

Cross-sectional study to describe allergic rhinitis flare-ups and associated airways phenotype in house dust mite sensitization.

ObjectivesTo quantify and describe flare-ups of house dust mite allergic rhinitis (HDM-AR) which had occurred during the last 12 months in a population of adults and children candidate for Allergen ImmunoTherapy (AIT). Next, to identify associated clinical features.Materials and methodsThis was an observational, multicenter, cross-sectional study that included patients aged ≥ 5 years with HDM-AR eligible for AIT and without prior AIT for at least 12 months. Flare-ups were all period with impairment of quality of life (QoL) and requiring a change in their usual treatment. Data were collected using medical records and patient questionnaires. Variables associated with the occurrence of ≥ 2 AR flare-ups were identified.Results1,701 patients were included (average age: 23 years, 51.5% males, 30.4% children, 17.7% adolescents and 51.9% adults). Severe and persistent AR affected 70.9% of them and 53.7% showed polysensitization. Asthma was associated with AR in 34.4% and was well-controlled in 58.5%. The occurrence of at least one AR flare-up in the year was reported by 77.7%, with an annual rate in the whole population of 2.6 ± 3.9 and a duration of 14.1 ± 17.1 days. Deeply or moderately AR-related degraded QoL was experienced by 39.5% and 64.6%, respectively. The occurrence of ≥ 2 AR flare-ups was reported by 54.5% and was associated with polysensitization, AR intermittence and severity.ConclusionAR flare-ups are frequent and impair QoL in HDM-allergic patients, suggesting that it could be considered as therapeutic targets

Effect of moderate forced physical activity on behaviour, lameness and osteochondrosis in growing pigs from two divergent lines selected for feed efficiency

International audienceIn pig farming, physical constraints and genetic selection for high production are risk factors for the development of leg disorders, such as degraded locomotor activity. Interactions between both factors need to be explored. The study was carried out on two replicates of 80 pure-bred Large White growing-finishing pigs from the 8th generation of two divergent lines selected for low and high residual feed intake (LRFI, HRFI). Each replicate included 40 LRFI pigs and 40 HRFI pigs, housed on partly slatted flooring in a room equipped with a sorter allowing access to electronic self-feeders during two replicates. Ear tags determined the side of the room to which the pigs were oriented after the sorter exit and the distance back to the sorter (short: spontaneous activity, long: forced activity (FA)). Lameness was assessed individually weekly using visual gait scoring. At slaughter (weight of 100 kg), postmortem quantification of osteochondrosis (OC) lesions was performed on both the proximal and distal extremities of the humerus and femur. Low RFI pigs showed a lower feed conversion ratio (P < 0.001). They also showed lower individual numbers of sorter crossings per day and a lower proportion of standing pigs, which confirmed their lower physical activity. Forced activity clearly increased the number of sorter crossings/d/pig (P < 0.001), and the magnitude of the effect of FA was clearly lower in LRFI pigs than in HRFI pigs. The occurrence of gait was low (less than 9% of recorded scores). The proportion of scores classified as stiffness was higher for LRFI pigs than in HRFI pigs (P < 0.0001). The average lameness score was also higher for LRFI pigs and lower with FA (P < 0.05). The pigs of the LRFI line showed higher OC scores on both the proximal humerus and femur (P < 0.001) and lower OC scores on the distal humerus with surface evaluation (P < 0.05). The carcasses of LRFI pigs were heavier with a higher lean meat percentage (P < 0.001). Most OC scores were unaffected by FA. Only the OC scores of the distal femur (slice method) were higher with increased activity in LRFI pigs, whereas they were lower in HRFI pigs (P < 0.05). Seric biomarkers of cartilage synthesis and degradation were higher for pigs from the LRFI line, but no correlation could be observed between individual OC scores and cartilage biomarker contents

Effect of divergent lines selected on feed efficiency and physical activity on lameness and osteochondrosis in growing pigs

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Effects of divergent lines on feed efficiency and physical activity on lameness and osteochondrosis in growing pigs

Locomotion disorders have been identified as a significant production disease for growing and finishing pigs, and a sign of reduced animal welfare (EU PROHEALTH project). Amongst them, lameness is a complex problem including animal-based and resources-based causes. Osteochondrosis (OC) is a very frequent disease in pigs, affecting cartilage. The study assessed the occurrence of lameness and OC in two divergent lines of Large-White selected according to a feed efficiency trait (HRFI, LRFI; high or low residual feed intake), submitted to constraints on the physical activity. Two experimental groups of 80 pigs (40 LRFI and 40 HRFI, ratio 1:1 of females and castrated males) were housed on partly slatted flooring in a room equipped withan electronic weighing device allowing pig access to electronic self-feeders, crossing a sorter. Pigs were equipped with ear tags for their individual electronic identification at the sorter and automatic feeders. The identification determined the side of the room to which the animal was directed after the sorter exit, and thus defined the distance to come back to the sorter (short: spontaneous activity, long: increased activity). Three times, at the beginning (wk3), middle (wk7) and end (wk13) of the growing-fattening period, video recordings were made during the 12 h daylight for screening the posture (standing, sitting, lying). Lameness was assessed weekly using a visual gait scoring (lameness score, 0: no, 1: lame). At slaughter, (weight of 100kg, between 21 and 22 wks of age), post-mortem quantification of OC lesions was performed on surfaces of both proximal and distal condyles of the humerus and femur (score 0 no lesion; score 5 severe lesion with loose fragment of cartilage). According to the variables, data were analyzed using a χ2 test or variance analysis with the main factors line, physical activity, sex, replicate and their interactions. The LRFI line showed fewer pigs standing during the daylight period at the three recording times (22.5±0.6 vs 28.3±0.6% of standing pigs during a 30 min interval, P<0.001). The LRFI pigs also showed a higher occurrence of lameness throughout the experimental period only in the second experimental group (34/313 vs 12/299 occurrences,χ2=9.16 df=1 P<0.01). The scores of OC of the LRFI pigs were also higher on the proximal condyle of the humerus (2.2 vs 1.5 P<0.001) and femur (1.7 vs 1.2 P<0.01). The pigs subjected to the increased activity treatment, crossed the sorter more frequently, whatever the genetic line (5.3±0.6 vs 3.7±1.9 crossings/day for increased vs spontaneous activity, P<0.01), but this treatment did not affect either the number of pigs standing during the daylight period or the OC scores. For these lines, selection on residual feed intake seemed to increase the prevalence of locomotor disorders. This effect of the line has to be investigated through the analysis of behavioural strategies within and between lines

Motion frozen (18)F-FDG cardiac PET.

BackgroundPET reconstruction incorporating spatially variant 3D Point Spread Function (PSF) improves contrast and image resolution. "Cardiac Motion Frozen" (CMF) processing eliminates the influence of cardiac motion in static summed images. We have evaluated the combined use of CMF- and PSF-based reconstruction for high-resolution cardiac PET.MethodsStatic and 16-bin ECG-gated images of 20 patients referred for (18)F-FDG myocardial viability scans were obtained on a Siemens Biograph-64. CMF was applied to the gated images reconstructed with PSF. Myocardium to blood contrast, maximum left ventricle (LV) counts to defect contrast, contrast-to-noise (CNR) and wall thickness with standard reconstruction (2D-AWOSEM), PSF, ED-gated PSF, and CMF-PSF were compared.ResultsThe measured wall thickness was 18.9 ± 5.2 mm for 2D-AWOSEM, 16.6 ± 4.5 mm for PSF, and 13.8 ± 3.9 mm for CMF-PSF reconstructed images (all P &lt; .05). The CMF-PSF myocardium to blood and maximum LV counts to defect contrasts (5.7 ± 2.7, 10.0 ± 5.7) were higher than for 2D-AWOSEM (3.5 ± 1.4, 6.5 ± 3.1) and for PSF (3.9 ± 1.7, 7.7 ± 3.7) (CMF vs all other, P &lt; .05). The CNR for CMF-PSF (26.3 ± 17.5) was comparable to PSF (29.1 ± 18.3), but higher than for ED-gated dataset (13.7 ± 8.8, P &lt; .05).ConclusionCombined CMF-PSF reconstruction increased myocardium to blood contrast, maximum LV counts to defect contrast and maintained equivalent noise when compared to static summed 2D-AWOSEM and PSF reconstruction