Polarization Maps Research Articles

Validation of the knowledge on the Noor evidence-based medicine questionnaire for healthcare professionals: Rasch analysis

<b>Aim</b>: This study aimed to examine the construct verification of the knowledge on the Noor evidence-based medicine (EBM) questionnaire using the Rasch measurement model.<br /> <b>Methods</b>: A cross-sectional study was conducted among ninety healthcare professionals working in a government hospital. The Rasch model was used to investigate the distribution of statistics, unidimensionality, polarity, misfit, and Wright map.<br /> <b>Results</b>: The Rasch analysis showed that the 15 items had high reliability of items at 0.96, while reliability for persons were 0.81. Item K15 is a misfit (PtMea Corr=0.22, outfit MnSq=1.95, outfit z-std=5.00, infit MnSq=1.63, infit z-std=3.60); the item does not contribute to the construction of scale but not degrading. Three items (K1, K14, and K9) can easily be answered even by low ability respondents.<br /> <b>Conclusions</b>: The Noor EBM questionnaire knowledge is robust with excellent psychometric properties that can be used for both research and clinical purposes.

COSMOGLOBE DR1 results

Cosmic birefringence is a parity-violating effect that might have rotated the plane of the linearly polarized light of the cosmic microwave background (CMB) by an angle β since its emission. This angle has recently been measured to be nonzero at a statistical significance of 3.6σ in the official Planck PR4 and 9-year WMAP data. In this work, we constrain β using the reprocessed BEYONDPLANCK LFI and COSMOGLOBE DR1 WMAP polarization maps. These novel maps have both lower systematic residuals and a more complete error description than the corresponding official products. Foreground EB correlations could bias measurements of β, and while thermal dust EB emission has been argued to be statistically nonzero, no evidence for synchrotron EB power has been reported. Unlike the dust-dominated Planck HFI maps, the majority of the LFI and WMAP polarization maps are instead dominated by synchrotron emission. Simultaneously constraining β and the polarization miscalibration angle, α, of each channel, we find a best-fit value of β = 0.35° ±0.70° with LFI and WMAP data only. When including the Planck HFI PR4 maps, but fitting β separately for dust-dominated, β> 70 GHz, and synchrotron-dominated channels, β≤70 GHz, we find β≤70 GHz = 0.53° ±0.28°. This differs from zero with a statistical significance of 1.9σ, and the main contribution to this value comes from the LFI 70 GHz channel. While the statistical significances of these results are low on their own, the measurement derived from the LFI and WMAP synchrotron-dominated maps agrees with the previously reported HFI-dominated constraints, despite the very different astrophysical and instrumental systematics involved in all these experiments.

Effect of Head Nurses’ Workplace Polarity Management Educational Intervention on Their Coaching Behavior

Purpose. To maintain the quality of patients care, head nurses (HNs) are confronting various contradicting issues that require the ability to manage polarities and concern coaching behaviors as exploring situations, building alliances, and maintaining communication with nurses. This study aimed to explore the effect of HNs’ workplace polarity management educational intervention on their coaching behaviors. Design. A quasiexperimental (pre-posttest) research design was used. Method. This study was conducted at Tanta International Teaching Hospital, on 12 HNs and 300 nurses using three tools: (I) a polarity management knowledge questionnaire; (II) a polarity map evaluation observational checklist; and (III) a nurses’ perception of the HNs’ coaching leadership behaviors questionnaire. The statistical tests used were as follows: the Kolmogorov-Smirnov test, the significance of the obtained results was judged at the 5% level; the marginal homogeneity test, ANOVA with repeated measures, the Wilcoxon signed ranks test, and the Friedman test. The study was conducted between end of 2021 and beginning of 2022. The educational intervention included 3 sessions: polarity management and the keys to manage it, polarity map (stability versus change), and head nurses’ role in managing polarity and how it reflects on their coaching leadership behavior. HNs’ ability to practice polarity management was classified into levels according to cutoff points: high >75%, moderate 60–75%, and low <60%. Results. Before intervention (66.7%, 100%) of head nurses had poor knowledge and low practice that changed after 3 months of intervention to be 58.3% and 41.7%, respectively. Before and 3 months after the intervention (70.0%, 33.7%) of nurses perceived that head nurses had a low and a moderate level of coaching, respectively. 70.0% of working nurses reported that they noticed that head nurses' coaching behaviors were low before the educational intervention, but the percentage decreased by half three months after the educational intervention. Conclusion. Implementing the educational intervention for head nurses about workplace polarity management significantly correlated with the nurses’ perception of their HNs’ coaching behaviors.

Superior piezoelectricity in lead-free barium titanate piezoceramics

Since the 21st century, increasing environmental protection and human health concern have been the driving force to develop lead-free piezoelectric materials with enhanced performances, and phase engineering strategy has been validated to be a viable method in numerous methodologies. Here, we gained a superb d33∼(637 ± 30) pC/N in lead-free (1–x)(Ba0.93Ca0.07)(Sn0.08Ti0.92)O3-x(Sb0.5Li0.5)TiO3 [abbreviated as (1–x)BCST-xSLT, 0 ≤ x ≤ 0.4% (in mole)] piezoelectrics utilizing chemical doping. To illustrate the relationship among composition-structure-performance, microstructure characterization, electrical properties measurement, first-principles calculation, and phase-field simulations were performed. Atomic-resolved polarization mapping of z-contrast imaging manifests the ferroelectric three phases (RO–T) coexist at the nanoscale with nanoscale polarization switching among them. Theoretical calculations and simulations confirm that the high-density nano-domain boundary bridges the polyphase coexisting nano-domains, which makes the polarization reversal easy, thus significantly reducing the energy barrier and polarization anisotropy among different phases.

Dark matter search with CMB: a study of foregrounds

The energy injected from dark matter annihilation and decay processes potentially raises the ionisation of the intergalactic medium and leaves visible footprints on the anisotropy maps of the cosmic microwave background (CMB). Galactic foregrounds emission in the microwave bands contaminate the CMB measurement and may affect the search for dark matter's signature. In this paper, we construct a full CMB data and foreground simulation based on the design of the next-generation ground-based CMB experiments. The foreground residual after the components separation on maps is fully considered in our data analysis, accounting for various contamination from the emission of synchrotron, thermal dust, free-free and spinning dust. We analyse the corresponding sensitivity on dark matter parameters from the temperature and polarization maps, and we find that the CMB foregrounds leave a non-zero yet controllable impact on the sensitivity. Comparing with statistics-only analysis, the CMB foreground residual leads to a factor of at most 19% weakening on energy-injection constraints, depending on the specific dark matter process and experimental configuration. Strong limits on dark matter annihilation rate and decay lifetime can be expected after foreground subtraction.

Civilian Oversight of Police Through the Lens of Polarities of Democracy

Following the murder of George Floyd, the U.S. Congress called upon the National Organization for Black Law Enforcement Executives (NOBLE) to play a role in the reimagining of policing in America, including a transformation of policing from a warrior to a guardian mentality. In turn, NOBLE partnered with the Institute for Polarities of Democracy (the Institute) to conduct an analysis of the <em>21st Century Policing Report</em> (the Report), which focused on addressing a myriad of issues that challenged the relationship between the police and communities. The Report determined there were six “pillars” necessary for effective policing in America, including (1) Trust and Legitimacy; (2) Policy and Oversight; (3) Technology and Social Media; (4) Community Policing and Crime Reduction; (5) Training and Education; and (6) Officer Wellness and Safety that encapsulated areas in need of attention. This review was an in-depth analysis conducted with support from the Walden University Center for Social Change through its strategic alliance with the Institute. In this article, we summarize the results of the Institute's initial review of Pillar Two of the Report, Policy and Oversight, with a specific focus on civilian oversight of police. Information to support this article was taken from original data that supported the compilation of the Report. The Institute’s analysis of a sampling of responses (from the participants against a survey question) was identified as correlating with polarities of democracy values. Additionally, a separate comprehensive critical analysis was conducted by comparing various principles believed necessary for effective civilian oversight of police against individual polarities of democracies value sets. Finally, the 5-Step SMALL Process (Seeing, Mapping, Assessing, Learning, and Leveraging) was identified as a tool that could be used to implement recommendations contained in the Report. From this tool, Polarity Maps for Justice and Due Process, as well as Participation and Representation, were developed to graphically depict the correlation of the polarities of democracy value sets with the preconditions for effective civilian oversight of police.

Automatic reorientation by deep learning to generate short-axis SPECT myocardial perfusion images

BackgroundSingle photon emission computed tomography (SPECT) myocardial perfusion images (MPI) can be displayed both in traditional short-axis (SA) cardiac planes and polar maps for interpretation and quantification. It is essential to reorient the reconstructed transaxial SPECT MPI into standard SA slices. This study is aimed to develop a deep-learning-based approach for automatic reorientation of MPI. MethodsA total of 254 patients were enrolled, including 226 stress SPECT MPIs and 247 rest SPECT MPIs. Fivefold cross-validation with 180 stress and 201 rest MPIs was used for training and internal validation; the remaining images were used for testing. The rigid transformation parameters (translation and rotation) from manual reorientation were annotated by an experienced nuclear cardiologist and used as the reference standard. A convolutional neural network (CNN) was designed to predict the transformation parameters. Then, the derived transform was applied to the grid generator and sampler in spatial transformer network (STN) to generate the reoriented image. A loss function containing mean absolute errors for translation and mean square errors for rotation was employed. A three-stage optimization strategy was adopted for model optimization: (1) optimize the translation parameters while fixing the rotation parameters; (2) optimize rotation parameters while fixing the translation parameters; (3) optimize both translation and rotation parameters together. ResultsIn the test set, the Spearman determination coefficients of the translation distances and rotation angles between the model prediction and the reference standard were 0.993 in X axis, 0.992 in Y axis, 0.994 in Z axis, 0.987 along X axis, 0.990 along Y axis and 0.996 along Z axis, respectively. For the 46 stress MPIs in the test set, the Spearman determination coefficients were 0.858 in percentage of profusion defect (PPD) and 0.858 in summed stress score (SSS); for the 46 rest MPIs in the test set, the Spearman determination coefficients were 0.9 in PPD and 0.9 in summed rest score (SRS). ConclusionsOur deep learning-based LV reorientation method is able to accurately generate the SA images. Technical validations and subsequent evaluations of measured clinical parameters show that it has great promise for clinical use.

Нечіткі моделі прийняття рішення при лазерній поляризаційно інваріантній діагностиці ішемії міокарда

Models of decision rules have been developed to support decision-making based on the principles of fuzzy logic for a system of azimuthally independent polarization mapping of azimuths and ellipticities of polarization images of biological layers. The reliability of differentiation of chronic and acute myocardial ischemia in laser polarization-invariant diagnosis was evaluated

Можливості верифікації позагоспітальної пневмонії в дітей за змінами багатопараметричної поляризаційно-фазової мікроскопії полікристалічних плівок легеневого експірату

The problem of early diagnosis and selection of target treatment of pneumonia in children during the years of the COVID-19 pandemic became acute, in particular, with regard to predicting the risk of severe disease, which prompted the search for new non-invasive diagnostic methods for verifying inflammation of the lung parenchyma. Purpose - to increase the effectiveness of the diagnosis of community-acquired pneumonia in children based on the analysis of the diagnostic value of the method of multiparameter polarization-phase microscopy of polycrystalline membranes of pulmonary expiratory condensate in the aspect of differential diagnosis in relation to patients with infectious inflammatory diseases of the upper respiratory tract. Materials and methods. In the Chernivtsi Regional Pediatric Hospital, 98 children with infectious inflammatory respiratory diseases were examined, in particular, 64 patients with pneumonia and 34 children suffering from infectious and inflammatory diseases of the upper respiratory tract. Biological material was collected from patients on the first day of hospitalization. The investigation of the laser-polarimetric images structure of pulmonary expiratory condensate was carried out in the traditional arrangement of the Stokes polarimeter. A universal analytical statistical approach was used for each two-dimensional distribution of the polarization azimuth values of the polycrystalline membranes of pulmonary expiratory condensate, namely, the determination of a set of statistical moments of the 1st to 4th orders (mean, variance, skewness and kurtosis). The obtained results were analyzed using methods of clinical epidemiology. Results. Polarization azimuth indexes and histograms of their values were determined for images of pulmonary expiratory samples of both groups of children. The comparative analysis of the obtained data confirmed that both samples are characterized by optical heterogeneity as an increase in the sensitivity of polarization mapping of lung expiratory samples. An increase in the optical anisotropy of polycrystalline membranes of lung expiratory condensate from patients with pneumonia was also revealed. The obtained indexes of all statistical moments for the purpose of pneumonia verifying had high sensitivity exceeding 98% and sufficient specificity. Conclusions. Sufficient diagnostic value of the method of multi-parameter polarization-phase microscopy of pulmonary expiratory air, which can be used in the verification of inflammation of the pulmonary parenchyma in children relative to patients with infectious inflammatory diseases of the upper respiratory tract, has been established. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Myocardial perfusion imaging with retrospective gating and integrated correction of attenuation, scatter, respiration, motion, and arrhythmia

BackgroundAbsolute quantitative myocardial perfusion SPECT requires addressing of aleatory and epistemic uncertainties in conjunction with providing image quality sufficient for lesion detection and characterization. Iterative reconstruction methods enable the mitigation of the root causes of image degradation. This study aimed to determine the feasibility of a new SPECT/CT method with integrated corrections attempting to enable absolute quantitative cardiac imaging (xSPECT Cardiac; xSC).MethodsWe compared images of prototype xSC and conventional SPECT (Flash3DTM) acquired at rest from 56 patients aged 71 ± 12 y with suspected coronary heart disease. The xSC prototype comprised list-mode acquisitions with continuous rotation and subsequent iterative reconstructions with retrospective electrocardiography (ECG) gating. Besides accurate image formation modeling, patient-specific CT-based attenuation and energy window-based scatter correction, additionally we applied mitigation for patient and organ motion between views (inter-view), and within views (intra-view) for both the gated and ungated reconstruction. We then assessed image quality, semiquantitative regional values, and left ventricular function in the images.ResultsThe quality of all xSC images was acceptable for clinical purposes. A polar map showed more uniform distribution for xSC compared with Flash3D, while lower apical count and higher defect contrast of myocardial infarction (p = 0.0004) were observed on xSC images. Wall motion, 16-gate volume curve, and ejection fraction were at least acceptable, with indication of improvements. The clinical prospectively gated method rejected beats ≥20% in 6 patients, whereas retrospective gating used an average of 98% beats, excluding 2% of beats. We used the list-mode data to create a product equivalent prospectively gated dataset. The dataset showed that the xSC method generated 18% higher count data and images with less noise, with comparable functional variables of volume and LVEF (p = ns).ConclusionsQuantitative myocardial perfusion imaging with the list-mode-based prototype xSPECT Cardiac is feasible, resulting in images of at least acceptable image quality.

A Hydraulic Axial Piston Pump Fault Diagnosis Based on Instantaneous Angular Speed under Non-Stationary Conditions

Due to the intense noise interference in hydraulic systems, it is extremely difficult to detect component faults through vibration signals. Diagnostic performance is also constrained by highly time-varying and non-stationary operating conditions. This study proposes to use instantaneous angular speed (IAS) signals that are both operational and state parameters as sources of information. Firstly, the instantaneous angular speed fluctuation (IASF) of a piston pump is analyzed theoretically, and it is concluded that its fluctuating components contain the health status information of the components. The IASF can then be obtained by subtracting the speed trend term from IAS signals obtained via a magneto-electric speed sensor. A synchro-extraction of the normal S transform (SNST) is proposed to process it via line-pass filtering. Finally, the filtered and reconstructed IASF signal is utilized to draw a two-dimensional polar coordinate map online. A non-stationary-condition test is carried out on the test platform to monitor the morphological characteristics of the valve plate under normal, slight, and severe wear conditions. The polar plot shows significant increases in speed fluctuations and oscillation times within a range from 180° to 270°. The relevant research results reflect that the IAS signal can provide a new method for monitoring the operating status of and conducting fault diagnoses for hydraulic equipment.

Deep learning approximation of attenuation maps for myocardial perfusion SPECT with an IQvarvec{cdot {}}SPECT collimator

BackgroundThe use of CT images for attenuation correction of myocardial perfusion imaging with single photon emission computer tomography (SPECT) increases diagnostic confidence. However, acquiring a CT image registered to a SPECT image is often not possible because most scanners are SPECT-only. It is possible to approximate attenuation maps using deep learning, but this has not yet been shown to work for a SPECT scanner with an IQvarvec{cdot {}}SPECT collimator. This study investigates whether it is possible to approximate attenuation maps from non-attenuation-corrected (nAC) reconstructions acquired with a SPECT scanner equipped with an IQvarvec{cdot {}}SPECT collimator.MethodsAttenuation maps and reconstructions were acquired retrospectively for 150 studies. A U–Net was trained to predict attenuation maps from nAC reconstructions using the conditional generative adversarial network framework. Predicted attenuation maps are compared to real attenuation maps using the normalized mean absolute error (NMAE). Attenuation-corrected reconstructions were computed, and the resulting polar maps were compared by pixel and by average perfusion per segment using the absolute percent error (APE). The training and evaluation code is available at https://gitlab.ub.uni-bielefeld.de/thuxohl/mu-map.ResultsPredicted attenuation maps are similar to real attenuation maps, achieving an NMAE of 0.020±0.007. The same is true for polar maps generated from reconstructions with predicted attenuation maps compared to CT-based attenuation maps. Their pixel-wise absolute distance is 3.095±3.199, and the segment-wise APE is 1.155±0.769.ConclusionsIt is feasible to approximate attenuation maps from nAC reconstructions acquired by a scanner with an IQvarvec{cdot {}}SPECT collimator using deep learning.

Detection and correction of patient motion in dynamic 15O-water PET MPI

BackgroundPatient motion constitutes a limitation to 15O-water cardiac PET imaging. We examined the ability of image readers to detect and correct patient motion using simulated motion data and clinical patient scans.MethodsSimulated data consisting of 16 motions applied to 10 motion-free scans were motion corrected using two approaches, pre-analysis and post-analysis for motion identification. Both approaches employed a manual frame-by-frame correction method. In addition, a clinical cohort was analyzed for assessment of prevalence and effect of motion and motion correction.ResultsMotion correction was performed on 94% (pre-analysis) and 64% (post-analysis) of the scans. Large motion artifacts were corrected in 91% (pre-analysis) and 74% (post-analysis) of scans. Artifacts in MBF were reduced in 56% (pre-analysis) and 58% (post-analysis) of the scans. The prevalence of motion in the clinical patient cohort (n = 762) was 10%. Motion correction altered exam interpretation in only 10 (1.3%) clinical patient exams.ConclusionFrame-by-frame motion correction after visual inspection is useful in reducing motion artifacts in cardiac 15O-water PET. Reviewing the initial results (parametric images and polar maps) as part of the motion correction process, reduced erroneous corrections in motion-free scans. In a large clinical cohort, the impact of motion correction was limited to few patients.

Respiratory signal estimation for cardiac perfusion SPECT using deep learning.

Respiratory motion induces artifacts in reconstructed cardiac perfusion SPECT images. Correction for respiratory motion often relies on a respiratory signal describing the heart displacements during breathing. However, using external tracking devices to estimate respiratory signals can add cost and operational complications in a clinical setting. We aim to develop a deep learning (DL) approach that uses only SPECT projection data for respiratory signal estimation. A modified U-Net was implemented that takes temporally finely sampled SPECT sub-projection data (100ms) as input. These sub-projections are obtained by reframing the 20-s list-mode data, resulting in 200 sub-projections, at each projection angle for each SPECT camera head. The network outputs a 200-time-point motion signal for each projection angle, which was later aggregated over all angles to give a full respiratory signal. The target signal for DL model training was from an external stereo-camera visual tracking system (VTS). In addition to comparing DL and VTS, we also included a data-driven approach based on the center-of-mass (CoM) strategy. This CoM method estimates respiratory signals by monitoring the axial changes of CoM for counts in the heart region of the sub-projections. We utilized 900 subjects with stress cardiac perfusion SPECT studies, with 302 subjects for testing and the remaining 598 subjects for training and validation. The Pearson's correlation coefficient between the DL respiratory signal and the reference VTS signal was 0.90, compared to 0.70 between the CoM signal and the reference. For respiratory motion correction on SPECT images, all VTS, DL, and CoM approaches partially de-blured the heart wall, resulting in a thinner wall thickness and increased recovered maximal image intensity within the wall, with VTS reducing blurring the most followed by the DL approach. Uptake quantification for the combined anterior and inferior segments of polar maps showed a mean absolute difference from the reference VTS of 1.7% for the DL method for patients with motion >12mm, compared to 2.6% for the CoM method and 8.5% for no correction. We demonstrate the capability of a DL approach to estimate respiratory signal from SPECT projection data for cardiac perfusion imaging. Our results show that the DL based respiratory motion correction reduces artefacts and achieves similar regional quantification to that obtained using the stereo-camera VTS signals. This may enable fully automatic data-driven respiratory motion correction without relying on external motion tracking devices.

Innovative Attention-Based Explainable Feature-Fusion VGG19 Network for Characterising Myocardial Perfusion Imaging SPECT Polar Maps in Patients with Suspected Coronary Artery Disease

Greece is among the European Union members topping the list of deaths related to coronary artery disease. Myocardial Perfusion Imaging (MPI) with Single-Photon Emission Computed Tomography (SPECT) is a non-invasive test used to detect abnormalities in CAD screening. The study proposes an explainable deep learning (DL) method for characterising MPI SPECT Polar Map images in patients with suspected CAD. Patient data were recorded at the Department of Nuclear Medicine of the University Hospital of Patras from 16 February 2018 to 28 February 2022. The final study population included 486 patients. An attention-based feature-fusion network (AFF-VGG19) was proposed to perform the diagnosis, and the Grad-CAM++ algorithm was employed to reveal potentially significant regions. AFF-VGG19’s agreement with the medical experts was found to be 89.92%. When training and assessing using the ICA findings as a reference, AFF-VGG19 achieved good diagnostic strength (accuracy of 0.789) similar to that of the human expert (0.784) and with more balanced sensitivity and specificity rates (0.873 and 0.722, respectively) compared to the human expert (0.958 and 0.648, respectively). The visual inspection of the Grad-CAM++ regions showed that the model produced 77 meaningful explanations over the 100 selected samples, resulting in a slight accuracy decrease (0.77). In conclusion, this research introduced a novel and interpretable DL approach for characterising MPI SPECT Polar Map images in patients with suspected CAD. The high agreement with medical experts, robust diagnostic performance, and meaningful interpretability of the model support the notion that attention-based networks hold significant promise in CAD screening and may revolutionise medical decision-making in the near future.

SPECT myocardial blood flow quantitation for the detection of angiographic stenoses with cardiac-dedicated CZT SPECT.

CZT SPECT with the enhanced imaging characteristic facilitates SPECT myocardial blood flow (MBF) quantitation moving toward a clinical utility to uncover myocardial ischemia. The purpose of this study was to investigate the diagnostic performance of stress MBF, myocardial flow reserve (MFR) and myocardial flow capacity (MFC) derived from CZT SPECT in the detection of coronary artery disease (CAD). One-hundred and eighty patients underwent two-day rest/adenosine-stress scans for SPECT MBF quantitation. All dynamic SPECT images were reconstructed and corrected with necessary corrections. The one-tissue two-compartment kinetic model was utilized to fit kinetic parameters (K1, k2 and FBV) by numeric optimization and converted to MBF from K1. Rest MBF, stress MBF and MFR in left ventricle and coronary territories were calculated from flow polar maps. MFC was assessed by extents of moderately and severely abnormal flow statuses using an integrated flow diagram. Per-patient and per-vessel analyses were performed to determine cutoff values for the detection of angiographically obstructive and flow-limited CAD. Using the threshold of ≥50% stenosis, 149 patients (82.78%) were classified to have obstructive lesions in 355 vessels (65.74%). Using the threshold of ≥70% stenosis, 113 patients (62.78%) were classified to have flow-limited lesions in 282 vessels (52.22%). On per-patient analysis, the optimal cutoff values of stress MBF and MFR to detect ≥50% stenosis were (1.44 ml/min/g, 1.96) and (1.34 ml/min/g and 1.75) to detect ≥70% stenosis. The optimal cutoff values for severely and combined moderately severely abnormal MFC extents were (2.3-2.5%, 23.1%) and (7.5%, 29.4%), respectively. The overall sensitivity of MFC (0.84-0.86, 0.86-0.90) to detect ≥50% and ≥70% lesions surpassed those of stress MBF (0.78. 0.78) and MFR (0.80, 0.75) (all p<0.05) with similar specificity (MFC=0.84-0.90, 0.87-0.91; stress MBF=0.87, 0.91; MFR=0.84, 0.89) (all p≥0.05). The non-invasive SPECT MBF quantitation using CZT SPECT is a reliable method to detect angiographically obstructive and flow-limited CAD. Myocardial flow capacity can outperform with higher diagnostic sensitivity than stress MBF or MFR alone.

Switchable and Functional Fluorophores for Multidimensional Single-Molecule Localization Microscopy.

Multidimensional single-molecule localization microscopy (mSMLM) represents a paradigm shift in the realm of super-resolution microscopy techniques. It affords the simultaneous detection of single-molecule spatial locations at the nanoscale and functional information by interrogating the emission properties of switchable fluorophores. The latter is finely tuned to report its local environment through carefully manipulated laser illumination and single-molecule detection strategies. This Perspective highlights recent strides in mSMLM with a focus on fluorophore designs and their integration into mSMLM imaging systems. Particular interests are the accomplishments in simultaneous multiplexed super-resolution imaging, nanoscale polarity and hydrophobicity mapping, and single-molecule orientational imaging. Challenges and prospects in mSMLM are also discussed, which include the development of more vibrant and functional fluorescent probes, the optimization of optical implementation to judiciously utilize the photon budget, and the advancement of imaging analysis and machine learning techniques.

Modelling Local Bubble analogs: synthetic dust polarization maps

ABSTRACT We present a study of synthetic observations of polarized dust emission at 353 GHz as seen by an observer within a cavity in the interstellar medium (ISM). The cavity is selected from a magnetohydrodynamic simulation of the local ISM with time-dependent chemistry, star formation, and stellar feedback in form of supernova explosions with physical properties comparable to the Local Bubble ones. We find that the local density enhancement together with the coherent magnetic field in the cavity walls makes the selected candidate a translucent polarization filter to the emission coming from beyond its domains. This underlines the importance of studying the Local Bubble in further detail. The magnetic field lines inferred from synthetic dust polarization data are qualitatively in agreement with the all-sky maps of polarized emission at 353 GHz from the Planck satellite in the latitudes interval 15° ≲ |b| ≲ 65°. As our numerical simulation allows us to track the galactic mid-plane only out to distances of $250\,$ pc, we exclude the region |b| ≲ 15° from our analysis. At large galactic latitudes, our model exhibits a high degree of small-scale structures. On the contrary, the observed polarization pattern around the Galactic Poles is relatively coherent and regular, and we argue that the global toroidal magnetic field of the Milky Way is important for explaining the data at |b| ≳ 65°. We show that from our synthetic polarization maps, it is difficult to distinguish between an open and a closed galactic cap using the inferred magnetic field morphology alone.

Cardiac fibroblast activation after acute myocardial infarction: pilot study using technetium 99m-iFAP SPECT

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Instituto Nacional de Investigaciones Nucleares (ININ). Background/Introduction Excessive fibrosis and persistent active fibroblasts can lead to increased left ventricular stiffness and, thus, heart failure. Cardiac remodeling is an important factor in the prognosis of patients after an acute myocardial infarction (AMI), and fibroblast activation is mandatory for repair and regeneration of the damage. There's an increasing use of molecular imaging in cardiovascular processes, such as molecules targeting fibroblast activation protein (FAP). FAP inhibitors (iFAP) radiolabeled with 68Ga in PET/CT have demonstrated adequate biodistribution and high uptake by activated fibroblasts in patients with cardiovascular risk factors and after acute myocardial infarction. Unfortunately, PET is not always widely available or cost-effective. Purpose This pilot study evaluates the feasibility of imaging activated fibroblast using 99mTc-iFAP SPECT in patients after AMI and its correlation with myocardial perfusion imaging (MPI), cardiac magnetic resonance (CMR) and invasive coronary angiography (ICA). Methods A prospective study with recent first AMI and non-previous known coronary artery disease patients were included. They underwent 99mTc-MIBI MPI SPECT and 99mTc-iFAP SPECT (including whole-body scan and thorax anterior static image acquired at 20, 60, and 120 min for the iFAP) and CMR/ICA within 14 days (+-2) after AMI. Qualitative and quantitative analysis was performed using a 17 segments model using QPS (Cedars Sinai) to determine the infarct extension from MPI and the correlation with the 99mTc-iFAP uptake pattern. A visual grading scale was established to assess localized tracer uptake and segments belonging to the hypoperfused area of the culprit's vessel. CMR yielded an area of injury with late gadolinium enhancement (LGE) and correlated with MPI studies. Results Five patients with STEMI were included (mean age of 63). Localized uptake of 99mTc-iFAP was observed in all patients with according to the affected coronary territory detected by ICA in 100% of patients (four anterior STEMI, one inferior STEMI). No radiotracer uptake was observed in the non-infarcted territories. Agreement between myocardial iFAP uptake, MIBI myocardial perfusion defect, CMR LGE, and ICA findings are presented in figure 1. An agreement of mismatch in polar maps between iFAP and MPI was performed, obtaining an excellent mismatch pattern in all patients, especially in transmural infarct segments. The best quality image was obtained at 60 minutes. Conclusions We successfully carried out the first pilot study with the patented 99mTc-iFAP molecule with SPECT technique. 99mTc-iFAP is a promising novel biomarker in assessing myocardial injury in sites where PET/CT is unavailable. There is an excellent correlation between iFAP uptake with the perfusion defect, LGE, and invasive anatomical obstruction findings. It is feasible and necessary to extend the inclusion of patients to a larger sample.

Real time three-dimensional transthoracic echocardiographic segmental volume analysis: quantitative and objective tool for assessing regional wall motion abnormalities in ischemic heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Evaluation of regional wall motion abnormality (RWMA) by 2D echocardiography (2DE) plays an important role in the diagnosing ischemic heart disease (IHD). However, 2DE is disadvantaged by being subjective, semi-quantitative, and expert-dependent. Recently, a method of measuring LV segmental volume by 3DE has been introduced, which enabled volume changes in LV regional to be measured. This study aimed to demonstrate the clinical usefulness of 3DE segmental volume analysis as an objective and quantitative tool for assessing RWMA in patients with IHD. Methods 33 patients with ischemic heart disease confirmed by coronary aniography and showing single vessel territory RWMA by 2DE were retrospectively enrolled. In the 2DE study, RWMAs were evaluated visually by and experienced physicians, and 17-segment bull's-eye polar maps were generated using a two-point scale, viz. 'normal' (showing normal contractility) or 'abnormal' (showing hypokinesis or akinesis). Culprit vessel territories were specified by a physician based on typical coronary artery distributions. In the 3DE study, two independent observers analyzed data using QLAB 3D quantification advanced software (version 10.0, Philips Healthcare). Segmental volumes of 17 LV segments were measured using a predetermined algorithm, and segmental volume ejection fractions (SVEFs) were calculated. Receiver operating characteristic (ROC) curve analysis was used to determine the SVEF cut-off value that best differentiated 'normal' and 'abnormal'. Using this cut-off value, 17-segment bull's-eye polar maps were generated. Reliability of correct predicting the culprit coronary arteries by 3DE bull's-eyes compared to 2DE ones was evaluated using Cohen's kappa co-efficients, which were also used for inter- and intra-observer variability analysis of 3DE bull's-eye derived culprit coronary artery predictions. Results Mean 3DE SVEFs were significantly lower for segments showing RWMA by 2DE. Additionally, among the segments determined to be normal by 2DE, 3D basal segmental EF is statistically lower than mid- and apical ones. The optimum SVEF cut-off value was 44%, with a sensitivity of 75.0% and a specificity of 73.9% (AUC = 0.801, 95% CI 0.763–0.838, p&amp;lt;0.001). The reliability of 3DE bull's-eye derived culprit coronary artery predictions was 81.8% (kappa = 0.672, 95% CI 0.555–0.789, p&amp;lt;0.001). Inter- and intra-observer variabilities of 3DE bull's-eye derived culprit coronary artery predictions were 97.0% (kappa = 0.947, 95% CI 0.894–0.100, p&amp;lt;0.001) and 93.9% (kappa = 0.897, 95% CI 0.827–0.967, p&amp;lt;0.001), respectively. Conclusion Assessment of RWMA using 3D echocardiographic segmental volume analysis was found to be feasible and reproducible, and its predictions of culprit coronary arteries well matched those of 2DE. 3DE segmental volume analysis could be used as a quantitative and objective tool for assessing RWMA in ischemic heart disease patients.