Polarization Maps Research Articles

Clinical Feasibility of Deep Learning-Based Attenuation Correction Models for Tl-201 Myocardial Perfusion SPECT.

We aimed to develop deep learning (DL)-based attenuation correction models for Tl-201 myocardial perfusion SPECT (MPS) images and evaluate their clinical feasibility. We conducted a retrospective study of patients with suspected or known coronary artery disease. We proposed a DL-based image-to-image translation technique to transform non-attenuation-corrected images into CT-based attenuation-corrected (CT AC ) images. The model was trained using a modified U-Net with structural similarity index (SSIM) loss and mean squared error (MSE) loss and compared with other models. Segment-wise analysis using a polar map and visual assessment for the generated attenuation-corrected (GEN AC ) images were also performed to evaluate clinical feasibility. This study comprised 657 men and 328 women (age, 65 ± 11 years). Among the various models, the modified U-Net achieved the highest performance with an average mean absolute error of 0.003, an SSIM of 0.990, and a peak signal-to-noise ratio of 33.658. The performance of the model was not different between the stress and rest datasets. In the segment-wise analysis, the myocardial perfusion of the inferior wall was significantly higher in GEN AC images than in the non-attenuation-corrected images in both the rest and stress test sets ( P < 0.05). In the visual assessment of patients with diaphragmatic attenuation, scores of 4 (similar to CT AC images) or 5 (indistinguishable from CT AC images) were assigned to most GEN AC images (65/68). Our clinically feasible DL-based attenuation correction models can replace the CT-based method in Tl-201 MPS, and it would be useful in case SPECT/CT is unavailable for MPS.

Mueller matrix polarization interferometry of optically anisotropic architectonics of biological tissue object fields: the fundamental and applied aspects

The presented results concern the diagnostic application of vector-parameter polarization mapping and polarization-interference phase scanning applied to layered azimuths and ellipticity polarization maps obtained with the help of digital holographic reproduction for phase-inhomogeneous tissue layers in the female reproductive system. The differential diagnosis of the pathological changes in optically anisotropic polycrystalline tissue components, specifically “benign (fibroids) and precancerous (endometriosis),” was investigated. All studies within the representative groups of the histological samples were conducted using circularly polarized laser radiation, ensuring azimuthal invariance and polarization measurement reliability. Integral and layered maps and polarization azimuths and ellipticity random variable distribution histograms were obtained from the microscopic images of histological sections from the female reproductive system tumors. Systematized tables present statistical moments which characterize azimuths and ellipticity polarization maps for fibroids and endometriosis tissues. It is shown that the statistical parameters (diagnostic markers) are the most sensitive to benign and precancerous changes in the female reproductive system tissues. The results of information analysis, including the accuracy determination of the diagnostic vector-parameter polarization and polarization-interference methods for detecting and differentiating the samples of fibroids and precancerous endometriosis tissues in the female reproductive system, are presented.

Constraining the Existence of Axion Clouds in M87* with Closure Trace Analyses

Black holes can amplify incoming bosonic waves via rotational superradiance, inducing bound states of ultralight bosons around them. This phenomenon has the potential to confine the parameter spaces of new bosons. Axions and axion-like particles (ALPs) are candidate beyond-standard-model particles that can form such clouds around supermassive black holes (SMBHs) and impact the polarization signal in a similar fashion to Faraday rotation via axion–photon coupling. Prior efforts have used polarized images from the Event Horizon Telescope (EHT) M87 2017 observations to limit the dimensionless axion–photon coupling to previously unexplored regions. However, with the novel calibration-insensitive quantities, closure traces, and conjugate closure trace products, it is possible to constrain the existence of axion clouds while avoiding the dominant sources of systematic uncertainties, e.g., station gains and polarization leakages. We utilize a simple geometric model for the polarization map of M87* to fit the model parameters with both simulated and real data sets and reach a comparable level of constraint in the accuracy with which an axion cloud may be excluded in M87. Future applications of our approach include subsequent M87* and Sgr A* observations by EHT and the next-generation EHT that are expected to produce stronger constraints across a wider range of axion and ALP masses. Because it does not require imaging, closure trace analyses may be applied to target active galactic nuclei for which imaging is marginal, extending the number of SMBHs from which axion limits may be obtained significantly.

Realizing Super‐High Piezoelectricity and Excellent Fatigue Resistance in Domain‐Engineered Bismuth Titanate Ferroelectrics

AbstractBismuth titanate (BIT) is widely known as one of the most prospective lead‐free ferroelectric and piezoelectric materials in advanced high‐temperature sensing applications. Despite significant advances in developing BIT ferroelectrics, it still faces major scientific and engineering challenges in realizing super‐high performance to meet next‐generation high‐sensitivity and light‐weight applications. Here, a novel ferroelectric domain‐engineered BIT ceramic system is conceived that exhibits super‐high piezoelectric coefficient (d33 = 38.5 pC N−1) and inverse piezoelectric coefficient (d33* = 46.7 pm V−1) at low electric field as well as excellent fatigue resistance (stable up to 107 cycles). The results reveal that the introduction of high‐density layered (001)‐type 180° domain walls with flexible polarization rotation features and the formation of small‐size multi‐domain states with low energy barriers are mainly responsible for the excellent electrical performance. To the best of knowledge, it is the first time to reveal such intriguing domain structures in BIT ceramics in detail, especially from the atomic‐scale perspective by using atomic number (Z)‐contrast imaging in combination with atomic‐resolution polarization mapping. It is believed that this breakthrough conduces to comprehensively understand structural features of ferroelectric domains in BIT ceramics, and also opens a window for future developments of super‐high performance in bismuth layer‐structured ferroelectrics via domain engineering.

Automatic Quantitative Assessment for Diagnostic and Therapeutic Response in Rodent Myocardial Infarct Model.

The purpose of this study was to investigate the most appropriate methodological approach for the automatic measurement of rodent myocardial infarct polar map using histogram-based thresholding and unsupervised deep learning (DL)-based segmentation. A rat myocardial infarction model was induced by ligation of the left coronary artery. Positron emission tomography (PET) was performed 60 min after the administration of 18F-fluoro-deoxy-glucose (18F-FDG), and PET was performed after injecting 64Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone). Single photon emission computed tomography was performed 60 min after injection of 99mTc-hexakis-2-methoxyisobutylisonitrile and 201Tl. Delayed contrast-enhanced magnetic resonance imaging was performed after injecting Gd-DTPA-BMA. Three types of thresholding methods (naive thresholding, Otsu's algorithm, and multi-Gaussian mixture model (MGMM)) were used. DL segmentation methods were based on a convolution neural network and trained with constraints on feature similarity and spatial continuity of the response map extracted from images by the network. The relative infarct sizes measured by histology and estimated R2 for 18F-FDG were 0.8477, 0.7084, 0.8353, and 0.9024 for naïve thresholding, Otsu's algorithm, MGMM, and DL segmentation, respectively. DL-based method improved the accuracy of MI size assessment.

Low-temperature grapho-epitaxial La-substituted BiFeO3 on metallic perovskite

Bismuth ferrite has garnered considerable attention as a promising candidate for magnetoelectric spin-orbit coupled logic-in-memory. As model systems, epitaxial BiFeO3 thin films have typically been deposited at relatively high temperatures (650–800 °C), higher than allowed for direct integration with silicon-CMOS platforms. Here, we circumvent this problem by growing lanthanum-substituted BiFeO3 at 450 °C (which is reasonably compatible with silicon-CMOS integration) on epitaxial BaPb0.75Bi0.25O3 electrodes. Notwithstanding the large lattice mismatch between the La-BiFeO3, BaPb0.75Bi0.25O3, and SrTiO3 (001) substrates, all the layers in the heterostructures are well ordered with a [001] texture. Polarization mapping using atomic resolution STEM imaging and vector mapping established the short-range polarization ordering in the low temperature grown La-BiFeO3. Current-voltage, pulsed-switching, fatigue, and retention measurements follow the characteristic behavior of high-temperature grown La-BiFeO3, where SrRuO3 typically serves as the metallic electrode. These results provide a possible route for realizing epitaxial multiferroics on complex-oxide buffer layers at low temperatures and opens the door for potential silicon-CMOS integration.

3D digital polarization-holographic wavelet histology in determining the duration of mechanical damage to the myocardium.

We aimed developing and experimentally validating methods for 3D scale-selective polarimetry of multiply scattered fields in diffuse myocardium layers for mechanical myocardial injury prescription histological differential diagnostics. We used the synthesis of diffuse object field polarization-interference registration and polarization-inhomogeneous field digital holographic reconstruction and layer-by-layer complex amplitudes distributions The method for selection single and diffuse object field multiply scattered components polarization maps is proposed. The conditions for eliminating the distorting influence of a depolarized background high level are found. On the basis of еру object field single scattered component polarization maps a large-scale selective wavelet analysis the criteria (markers) for mechanical myocardial injury different prescription diagnosis was determinate. Excellent accuracy mechanical injury myocardium necrotic changes with different duration using polarization-interference wavelet differentiation were achieved.

Statistical properties of galactic synchrotron temperature and polarization maps — a multi-frequency comparison

Understanding the statistical properties of synchrotron emission from our Galaxy is valuable from the perspective of observations targeting signals of cosmological origin, as well as for understanding physical processes in our Galaxy. In this work, we extend the analysis of Rahman et al. [1] to — (a) all-sky observed maps of total foreground emissions at different frequencies provided by WMAP, Planck and Stockert-Villa,(b) component separated synchrotron temperature maps provided by WMAP, Planck and BeyondPlanck, and (c) component separated polarization maps provided by WMAP and Planck. The tools we use are Minkowski functionals and tensors.Our main goals are twofold. First, we determine the variation of morphological properties of the total foreground maps with observing frequency and compare with simulations. This study elucidates how the morphology varies with frequency due to the relative dominance of different foreground components at different frequencies. Secondly, we determine the nature of non-Gaussianity and statistical isotropy of synchrotron fluctuations towards smaller scales using various component separated synchrotron temperature and polarization maps. We find that all maps exhibit kurtosis-type non-Gaussianity, in agreement with the Haslam map. This result can be an important input for the modelling of small-scale synchrotron fluctuations for component separation pipelines. This also suggests that residual synchrotron contamination in CMB will manifest as kurtosis and will not be captured by three-point statistics.From a comparison of the different component separated maps, we find that BeyondPlanck and WMAP MCMC-e agree well with Haslam at all scales. The other maps show differences of varying statistical significance.Our analysis suggests a combination of residual AME and/or free-free emissions and point sources as contributing to these differences, and underscores the need for further improvement of the pipelines.

Minkowski Functionals in 𝖲𝖮(3) for the spin-2 CMB polarisation field

The study of the angular power spectrum of Cosmic Microwave Background (CMB) anisotropies, both in intensity and in polarisation, has led to the tightest constraints on cosmological parameters. However, this statistical quantity is not sensitive to any deviation from Gaussianity and statistical isotropy in the CMB data. Minkowski Functionals (MFs) have been adopted as one of the most powerful statistical tools to study such deviations, since they characterise the topology and geometry of the field of interest. In this paper, we extend the application of MFs to CMB polarisation data by introducing a new formalism, where we lift the spin 2 polarisation field to a scalar function in a higher-dimensional manifold: the group of rotations of the sphere, SO(3). Such a function is defined as f = Q cos(2ζ) - U sin(2ζ). We analytically obtain the expected values for the MFs of f in the case of Gaussian isotropic polarisation maps. Furthermore, we present a new pipeline which estimates these MFs from input HEALPix polarisation maps. We apply it to CMB simulations in order to validate the theoretical results and the methodology. The pipeline is to be included in the publicly available Python package Pynkowski .

Physiological myocardial 18F-FDG uptake pattern in oncologic PET/CT: comparison with findings in cardiac sarcoidosis.

Physiological myocardial 18F-fluorodeoxyglucose (18F-FDG) uptake in oncologic positron emission tomography (PET)/computed tomography (CT) is commonly observed with multiple variations under clinical fasting conditions. The purpose of the present study was to evaluate physiological myocardial 18F-FDG uptake pattern by comparing with the results in cardiac sarcoidosis. A total of 174 examinations in 174 patients without cardiac disease and 27 examinations in 17 patients with cardiac sarcoidosis were performed. The polar map images generated from 18F-FDG PET/CT data were visually assessed as "basal-ring," "focal," and "focal on diffuse" patterns. Semi-quantitative analysis was also performed using the regional relative 18F-FDG uptake (% uptake). On visual analysis, the "focal on diffuse" pattern was the most common in both examinations (43% and 59%, respectively). The physiological % uptake in the lateral and basal septal walls tended to be higher. Subgroup analysis showed significantly higher uptake in the mid-wall and left circumflex territory. In cardiac sarcoidosis patients, there was a significant difference only between segments 2 and 15 (p=0.04). No significant differences were observed between the base-mid-apical territory and coronary artery branch territory. High 18F-FDG uptake in the basal septal walls is likely to be observed as both physiological uptake in patients without cardiac disease and pathological uptake in patients with cardiac sarcoidosis.

The Leadership Roles of the “Man of Knowledge”: Navigating Polaritites and Polarisations in Polish Academia

This paper has three objectives. First, it seeks to reestablish Florian Znaniecki as the founding father of the sociology of leadership by emphasising his enduring relevance in this field. Second, it aims to revive Znaniecki’s theory of social persons and highlight his innovative contributions to the broader theory of social roles. Last but not least, it endeavours to apply this theory to the unique challenges faced by academic leaders in Poland. To articulate and operationalise the concealed, dynamic, and creative logic inherent in Znaniecki’s theory, this paper draws on Barry Johnson’s polarity-thinking paradigm with its signature methodological tool, the so-called polarity map. Through an in-depth analysis of 36 interviews with academic leaders in Poland, the present study reveals the individualised approaches and strategies these leaders employ in navigating the polarities in Polish academia. Znaniecki’s theory allows four principal polarities in the experiences of Polish academic leaders to be identified: (a) the fundamental intra-person strain between social roles and the Self, which splits into two sub-tensions, that is, (b) the intra-Self strain between the reflected and reconstructed Self, and (c) the intra-role strain between social function and social position, which in turn entails also (d) the moral strain between moral obligations and moral rights. The management of these strains can result in either detrimental polarisations, leading to the deconstruction of the social person, social role, and Self, or the nurturing of creative polarities, fostering the development of a more creative and adaptive social person, social role, and Self.

Magnetic Fields and Plasma Heating in the Sun’s Atmosphere

We use the first publicly available data from the Daniel K. Inouye Solar Telescope to track magnetic connections from the solar photosphere into the corona. We scrutinize relationships between chromospheric magnetism and bright chromospheric, transition region, and coronal plasmas. In 2022 June, the Visible Spectro-Polarimeter (ViSP) instrument targeted unipolar network within a decaying active region. ViSP acquired rastered scans with longitudinal Zeeman sensitivities of 0.25 Mx cm−2 (Fe i, 630.2 nm) and 0.5 Mx cm−2 (Ca ii, 854.2 nm). ViSP was operated in a “low” resolution mode (0.″214 slit width, spectral resolution R≈70,000 ) to produce polarization maps over a common area of 105″ × 50″. Data from the Solar Dynamics Observatory and Interface Region Imaging Spectrograph are combined to ask: Why is only a fraction of emerging flux filled with heated plasma? What is the elemental nature of the plasmas? No correlations were found between heated plasma and the properties of chromospheric magnetic fields derived from the weak field approximation, on scales below supergranules. Processes hidden from our observations control plasma heating. While improved magnetic measurements are needed, these data indicate that “the corona is a self-regulating forced system.” Heating depends on the state of the corona, not simply on boundary conditions. Heating models based upon identifiable bipolar fields, including cool loops, tectonics, and observable magnetic reconnection, are refuted for these regions with unipolar chromospheric magnetic fields.

Virtual platform for computer simulation of radionuclide imaging in nuclear cardiology: Comparison with clinical data

BACKGROUND: In radionuclide imaging, in vivo human clinical studies are limited because of radiation exposure and ethical concerns; therefore, mathematical modeling and in silico computer simulations based on digital models are becoming increasingly important. In the English-language literature, this approach is called “virtual clinical trials.” AIMS: This study aimed to develop software tools for the simulation of radionuclide visualization of myocardial perfusion by single-photon emission computed tomography combined with computed tomography using 99mTc-MIBI as the radiopharmaceutical and perform studies aimed at improving the accuracy of single-photon emission computed tomography. MATERIALS AND METHODS: A software package “Virtual platform for simulations of single-photon emission computed tomography combined with computed tomography method in nuclear cardiology” was developed using digital patient models, a scanner, and assessment of the state of the myocardium using digital images of the left ventricle in the form of a “polar map.” Verification of the software package was performed by comparison with clinical data obtained at the National Medical Research Center of Cardiology Named After Academician E.I. Chazov (Moscow). Simulation computer tests were performed, in which the accuracy of assessing the state of the myocardium was assessed, depending on the approach to normalizing the polar map and corrective factors in the reconstruction algorithm. RESULTS: The results of the simulation tests revealed that the assessment of left ventricular myocardial perfusion significantly depended on the method of normalizing the polar map and considered corrective factors in the reconstruction algorithm. The most accurate estimates were obtained by calculating the normalization coefficient from the average value of activity in the normal zone of the myocardium. The common approach to pixel normalization with maximum intensity can lead to errors. The results of the virtual trials were fully consistent with clinical observations. CONCLUSIONS: The transition from relative normalized values of activity in the myocardium to absolute quantitative estimates may eliminate existing limitations and uncertainties and is the main condition for improving the diagnostic accuracy of single-photon emission computed tomography combined with computed tomography in nuclear cardiology.

Sensitized Emission Imaging Allows Nanoscale Surface Polarity Mapping of α-Synuclein Amyloid Fibrils.

When misfolded, α-Synuclein (α-Syn), a natively disordered protein, aggregates to form amyloid fibrils responsible for the neurodegeneration observed in Parkinson's disease. Structural studies revealed distinct molecular packing of α-Syn in different fibril polymorphs and variations of interprotofilament connections in the fibrillar architecture. Fibril polymorphs have been hypothesized to exhibit diverse surface polarities depending on the folding state of the protein during aggregation; however, the spatial variation of surface polarity in amyloid fibrils remains unexplored. To map the local polarity (or hydrophobicity) along α-Syn fibrils, we visualized the spectral characteristics of two dyes with distinct polarities-hydrophilic Thioflavin T (ThT) and hydrophobic Nile red (NR)─when both are bound to α-Syn fibrils. Dual-channel fluorescence imaging reveals uneven partitioning of ThT and NR along individual fibrils, implying that relatively more polar/hydrophobic patches are spread over a few hundred nanometers. Remarkably, spectrally resolved sensitized emission imaging of α-Syn fibrils provides unambiguous evidence of energy transfer from ThT to NR, implying that dyes of dissimilar polarity are in close proximity. Furthermore, spatially resolved fluorescence spectroscopy of the solvatochromic probe NR allowed us to quantitatively map the range and variation of the polarity parameter ET30 along individual fibrils. Our results suggest the existence of interlaced polar and nonpolar nanoscale domains throughout the fibrils; however, the relative populations of these patches vary considerably over larger length scales likely due to heterogeneous packing of α-Syn during fibrilization and dissimilar exposed polarities of polymorphic segments. The employed method may provide a foundation for imaging modalities of other similar structurally unresolved systems with diverse hydrophobic-hydrophilic topology.

3D digital holographic polarimetry of diffuse optically anisotropic biological tissue object fields

The experimental validation of methods for the digital holographic 3D layer-by-layer reconstruction of complex amplitude distributions in different phase planes of diffuse biological tissue histological section microscopic images with a subsequent reconstruction of azimuth and ellipticity polarization maps is presented. Polarization dependencies of the integral and layer-by-layer vector structure of the laser object field azimuth and ellipticity distributions in two types of biological layer samples—the fibrous myocardium and parenchymal liver—have been investigated. Scenarios and dynamics of changes in the values of statistical moments of the first to fourth orders, which characterize the integral and layer-by-layer polarization maps of diffuse biological tissue histological section microscopic images with different morphological structures, have been determined. Criteria for selecting the polarization components of the object field that are formed by acts of scattering of different multiplicities have been identified. An example of biomedical application in cancer detection of biological tissues is provided.

Hemispherical power asymmetry in intensity and polarization for Planck PR4 data

One of the foundations of the Standard Model of Cosmology is statistical isotropy, which can be tested, among other probes, through the study of the Cosmic Microwave Background (CMB). However, a hemispherical power asymmetry on large scales has been reported for WMAP and Planck data by different works.The statistical significance is above 3σ for temperature, suggesting a directional dependence of the local power spectrum, and thus a feature beyond the ΛCDM model. With the third release of the Planck data (PR3), a new analysis was performed including the E-mode polarization maps, finding an asymmetry at a modest level of significance. In this work, we perform an asymmetry analysis in intensity and polarization maps for the latest Planck processing pipeline (PR4). We obtain similar results to those obtained with PR3, with a slightly lower significance (2.8% for the Sevem method)for the amplitude of the E-mode local variance dipole as well as a significant variability with the considered mask.In addition, a hint of a possible T-E alignment between the asymmetry axes is found at the level of ∼ 5%. For the analysis, we have implemented an alternative inpainting approach in order to get an accurate reconstruction of the E-modes. More sensitive all-sky CMB polarization data, such as those expected from the future LiteBIRD experiment, are needed to reach a more robust conclusion on the possible existence of deviations from statistical isotropy in the form of a hemispherical power asymmetry.

A Spatially Resolved X-Ray Polarization Map of the Vela Pulsar Wind Nebula

In this paper, we present a full spatially resolved polarization map for the Vela pulsar wind nebula (PWN) observed by IXPE. By employing effective background discrimination techniques, our results show a remarkably high degree of local polarization in the outskirt region, exceeding 60% (55%) with a probability of 95% (99%), which approaches the upper limit predicted by the synchrotron emission mechanism. The high degree of polarization suggests that the turbulent magnetic energy is at most 33% of the ordered one. In addition, the X-ray polarization map exhibits a toroidal magnetic field pattern that is consistent with the field revealed by radio observations across the entire nebula. This consistency reveals that the observed X-ray and radio emissions are radiated by electrons from the same magnetic field. Different from the Crab PWN, the consistency observed in the Vela PWN may be attributed to the interaction between the reverse shock of the supernova blast wave and the PWN, which leads to a displacement between the synchrotron-cooled nebula and the fresh nebula close to the pulsar. These findings deepen our understanding of the structure and evolution of the Vela PWN and the magnetohydrodynamic interaction in PWNe.

Accelerating search for the polar phase stability of ferroelectric oxide by machine learning

Machine learning emerges to accelerate first-principles calculations in materials discovery and property prediction, but developing high-accuracy prediction models requires training on large datasets of relaxed structures, which can be computationally expensive. Besides, the crystal structure prediction algorithms show promising aspects but often deviate from the ground state, leading to poor predictions. Using a crystal graph convolutional neural network, we propose an alternative and efficient method of finding the ground state by utilizing the total energy of random unrelaxed structures. The prediction model is trained on a small dataset of unrelaxed energy obtained from first-principles calculations and effectively predicts the total energy of random structures with an accuracy almost equivalent to first-principles calculations. The resulting energy landscape is then reconstructed in terms of polarity. This leads to establishing an energy landscape of a perovskite oxide in a cost-effective way, enabling a polar phase stability map of strained BaTiO3, a representative ferroelectric oxide. The proposed methodology efficiently allows to obtain the ground state by eliminating the computationally intensive procedure of structure optimization, thus accelerating the ground state search to map out the phase stability of strained perovskite materials in a practical manner.

Comparison of calculation algorithms between arithmetic mean of washout rate and total-count-based washout rate in single-photon emission computed tomography

Abstract Background Myocardial washout rate (WR) analysis of radiopharmaceuticals is utilized in nuclear cardiology to evaluate the clinical pathophysiology of the heart. WR is defined as the ratio of the difference between the count in the early image and the time-decay-corrected delayed image divided by the former. The arithmetic mean of washout rate (AMWR) of each segment is a commonly used algorithm for calculating WR from a polar map in single-photon emission computed tomography (SPECT). However, in this algorithm, uneven radiotracer uptake among segments affects WR calculation. Therefore, we newly formulated a modified algorithm for calculating WR based on the total count (TCWR). Purpose To clarify the usefulness of TCWR by comparing the calculation algorithms between TCWR and AMWR. Methods The WR of iodine-123-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) was calculated using TCWR and AMWR, and WR values using TCWR and AMWR were compared by disease. We focused on the patients with specific conditions that decreased BMIPP uptake in the early image — CD36 deficiency is a human loss-of-function genetic mutation model for BMIPP uptake, and old myocardial infarction (OMI) may present such a clinical phenotype. Also, patients with triglyceride deposit cardiomyovasculopathy (TGCV) were enrolled since a markedly decreased BMIPP WR (&amp;lt;10%) is one of the essential criteria for its diagnosis. Consecutive patients who underwent BMIPP scintigraphy were reviewed, and the analysis included patients without detectable cardiovascular diseases (normal) (n = 11), those with CD36 deficiency (n = 6), TGCV (n = 14), TGCV with OMI (n = 17), and non-TGCV with OMI (n = 10). Results WR values using TCWR and AMWR did not differ significantly in the following groups: normal, 27.4 ± 8.5 and 27.3 ± 8.5% (p = 0.97); CD36 deficiency, -3.2 ± 6.5 and -4.1 ± 7.4% (p = 0.81); TGCV, 2.4 ± 6.3 and 2.2 ± 6.3% (p = 0.93); and TGCV with OMI, -0.9 ± 7.6 and -3.7 ± 8.4% (p = 0.32). However, AMWR showed a lower WR than TCWR in non-TGCV with OMI (4.8 ± 8.7 and 18.9 ± 6.7%, p = 0.0008). Conclusions TCWR is suitable for calculating WR using SPECT polar maps even in cases with heterogeneous radiotracer uptake, such as OMIs. TCWR may be applied to measuring the WR of radiopharmaceuticals other than BMIPP in investigating the pathophysiology of heart diseases.Definition of calculation algorithms.Comparison of TCWR and AMWR.

Perte de masse des étoiles évoluées via des observations avec SPHERE au VLT

The Asymptotic Giant Branch (AGB) stars lose a huge amount of matter and the mechanism of this massloss is not yet well understood. We wanted to better understand this mechanism using data from SPHERE. IRAS spectra of three AGB stars V1943_Sgr, Psi_Phe et Ups_Cet have been used to determine their properties. The polarimetric data of each star from ZIMPOL allowed us to make they polar maps. Thanks to theses colormaps, we were able to prove the existence of dust envelop around each star confirming that they are AGB stars.