Fast Scanning Research Articles

Precision brain morphometry using cluster scanning

Abstract Measurement error limits the statistical power to detect group differences and longitudinal change in structural MRI morphometric measures (e.g., hippocampal volume, prefrontal cortical thickness). Recent advances in scan acceleration enable extremely fast T1-weighted scans (~1 minute) that achieve morphometric errors that are close to the errors in longer traditional scans. As acceleration allows multiple scans to be acquired in rapid succession, it becomes possible to pool estimates to increase measurement precision, a strategy known as “cluster scanning.” Here, we explored brain morphometry using cluster scanning in a test-retest study of 40 individuals (12 younger adults, 18 cognitively unimpaired older adults, and 10 adults diagnosed with mild cognitive impairment or Alzheimer’s Dementia). Morphometric errors from a single compressed sensing (CS) 1.0 mm scan (CS) were, on average, 12% larger than a traditional scan using the Alzheimer’s Disease Neuroimaging Initiative (ADNI) protocol. Pooled estimates from four clustered CS acquisitions led to errors that were 34% smaller than ADNI despite having a shorter total acquisition time. Given a fixed amount of time, a gain in measurement precision can thus be achieved by acquiring multiple rapid scans instead of a single traditional scan. Errors were further reduced when estimates were pooled from eight CS scans (51% smaller than ADNI). Neither pooling across a break nor pooling across multiple scans of different spatial resolutions boosted this benefit. We discuss the potential of cluster scanning to improve morphometric precision, boost statistical power, and produce more sensitive disease progression biomarkers.

The contrast-enhanced FAST exam in pediatric and adult thoracoabdominal trauma.

The contrast-enhanced FAST exam in pediatric and adult thoracoabdominal trauma.

Extended-Aperture Shape Measurements Using Spatially Partially Coherent Illumination (ExASPICE).

We have recently demonstrated that the 3D shape of micro-parts can be measured using LED illumination based on speckle contrast evaluation in the recently developed SPICE profilometry (shape measurements based on imaging with spatially partially coherent illumination). The main advantage of SPICE is its improved robustness and measurement speed compared to confocal or white light interferometry. The limited spatial coherence of the LED illumination is used for depth discrimination. An electrically tunable lens in a 4f-configuration is used for fast depth scanning without mechanically moving parts. The approach is efficient, takes less than a second to capture required images, is eye-safe and offers a depth of focus of a few millimeters. However, SPICE's main limitation is its assumption of a small illumination aperture. Such a small illumination aperture affects the axial scan resolution, which dominates the measurement uncertainty. In this paper, we propose a novel method to overcome the aperture angle limitation of SPICE by illuminating the object from different directions with several independent LED sources. This approach reduces the full width at half maximum of the contrast envelope to one-eighth, resulting in a twofold improvement in measurement accuracy. As a proof of concept, shape measurements of various metal objects are presented.

Nanocalorimetry of Nanoscaled Ni/Al Multilayer Films: On the Methodology to Determine Reaction Kinetics for Highly Reactive Films

Free‐standing Ni/Al multilayer films with a planar morphology, a bilayer thickness of 20 nm, and an average composition of Ni50Al50 (at%) deposited by direct current magnetron sputtering are investigated by nanocalorimetry and conventional calorimetry. Both the novel fast differential scanning calorimeter (FDSC) Flash DSC 2+ from Mettler–Toledo (MT) and conventional calorimeter MT DSC 3 are used to cover a range of heating rates from 0.1 to 104 K s−1. A quantitative kinetic study of the interdiffusion and phase reaction sequence is performed via a Kissinger analysis covering five orders of magnitude of heating rates. Using the calorimetric data, the derived apparent activation energies suggest monotonic reaction kinetics over the entire range of heating rates applied. To correct the thermal lag at the highest heating rates with the FDSC for nonadhered free‐standing films, a new methodology for its correction is used. Overall, this work extends the application of commercial FDSC to nonadhered films.

Fourier transform-based post-processing drift compensation and calibration method for scanning probe microscopy

Scanning probe microscopy (SPM) is ubiquitous in nanoscale science allowing the observation of features in real space down to the angstrom resolution. The scanning nature of SPM, wherein a sharp tip rasters the surface during which a physical setpoint is maintained via a control feedback loop, often implies that the image is subject to drift effects, leading to distortion of the resulting image. While there are in-operando methods to compensate for the drift, correcting the residual linear drift in obtained images is often neglected. In this paper, we present a reciprocal space-based technique to compensate the linear drift in atomically-resolved scanning probe microscopy images without distinction of the fast and slow scanning directions; furthermore this method does not require the set of SPM images obtained for the different scanning directions. Instead, the compensation is made possible by the a priori knowledge of the lattice parameters. The method can also be used to characterize and calibrate the SPM instrument.

Assessing deep learning reconstruction for faster prostate MRI: visual vs. diagnostic performance metrics

ObjectiveDeep learning (DL) MRI reconstruction enables fast scan acquisition with good visual quality, but the diagnostic impact is often not assessed because of large reader study requirements. This study used existing diagnostic DL to assess the diagnostic quality of reconstructed images.Materials and methodsA retrospective multisite study of 1535 patients assessed biparametric prostate MRI between 2016 and 2020. Likely clinically significant prostate cancer (csPCa) lesions (PI-RADS ≥\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\ge$$\\end{document} 4) were delineated by expert radiologists. T2-weighted scans were retrospectively undersampled, simulating accelerated protocols. DL reconstruction (DLRecon) and diagnostic DL detection (DLDetect) were developed. The effect on the partial area under (pAUC), the Free-Response Operating Characteristic (FROC) curve, and the structural similarity (SSIM) were compared as metrics for diagnostic and visual quality, respectively. DLDetect was validated with a reader concordance analysis. Statistical analysis included Wilcoxon, permutation, and Cohen’s kappa tests for visual quality, diagnostic performance, and reader concordance.ResultsDLRecon improved visual quality at 4- and 8-fold (R4, R8) subsampling rates, with SSIM (range: −1 to 1) improved to 0.78 ± 0.02 (p < 0.001) and 0.67 ± 0.03 (p < 0.001) from 0.68 ± 0.03 and 0.51 ± 0.03, respectively. However, diagnostic performance at R4 showed a pAUC FROC of 1.33 (CI 1.28–1.39) for DL and 1.29 (CI 1.23–1.35) for naive reconstructions, both significantly lower than fully sampled pAUC of 1.58 (DL: p = 0.024, naïve: p = 0.02). Similar trends were noted for R8.ConclusionDL reconstruction produces visually appealing images but may reduce diagnostic accuracy. Incorporating diagnostic AI into the assessment framework offers a clinically relevant metric essential for adopting reconstruction models into clinical practice.Clinical relevance statementIn clinical settings, caution is warranted when using DL reconstruction for MRI scans. While it recovered visual quality, it failed to match the prostate cancer detection rates observed in scans not subjected to acceleration and DL reconstruction.

Phase Transition Thermodynamics of 1,3,5-Tris-(α-naphthyl)benzene: Theory and Experiment.

1,3,5-Tris-(α-naphthyl)benzene is an organic non-electrolyte with notable stability of an amorphous phase. Its glassy and supercooled liquid states were previously studied by spectroscopic and calorimetric methods. Despite the continuing interest in its amorphous state and, particularly, vapor-deposited glasses, the thermodynamic parameters of the vaporization of 1,3,5-tris-(α-naphthyl)benzene have not been obtained yet. Likewise, the reliable evaluation of the thermodynamic parameters of fusion below the melting point, required to establish the thermodynamic state of its glass, is still an unsolved problem. In this work, the heat capacities of crystalline and liquid phases, the temperature dependence of the saturated vapor pressures, fusion and vaporization enthalpies were determined using differential and fast scanning calorimetry and were verified using the estimates based on solution calorimetry. The structural features of 1,3,5-tris-(α-naphthyl)benzene are discussed based on the computations performed and the data on the molecular refractivity. The consistency between the values obtained by independent techniques was demonstrated.

Evaluation of Focused Assessment With Sonography for Trauma Completeness of Children in the Clinical Setting.

We evaluated the completeness of real-world Focused Assessment with Sonography for Trauma (FAST) in children after blunt abdominal trauma by benchmarking against established expert guidelines. We conducted a retrospective cohort study, analyzing a random sample of FASTs from two urban pediatric emergency departments. Two experts reviewed and labeled all FASTs for completeness using a predefined guideline of 5 anatomic views and 30 landmarks. We compared frequencies of views and landmarks as medians with interquartile ranges. We analyzed 200 FASTs, consisting of 1636 video clips, performed by 31 clinicians representing 198 children with a median age of 10 years (IQR 5,14). Over half of FASTs (52%) had all 5 views. The right upper quadrant view was most commonly visualized (96.5%), and suprapubic sagittal was least (65%). None of the FASTs included all 30 landmarks, ranging from 0 to 28 and median of 19 (IQR 15,23). The least visualized landmark of the right and left upper quadrants was caudal liver edge (60%) and splenic tip (64%), respectively. In the pericardial view, it was left atrium (45%). In both transverse and sagittal pelvic views, retro-uterine space was least visualized in girls, 21 and 29% respectively. In our study, most FAST views and landmarks were visualized. However, the pelvic sagittal view was the least frequently visualized view, and caudal liver edge was the least visualized landmark. Future research should evaluate if variability in visualizing FAST views and landmarks correlates with inconsistencies in diagnostic test performance.

Characterizing the mechanism of catecholamines transport in the Mesenteric lymph Node (MLN) using Fast Scan Cyclic Voltammetry (FSCV).

Abstract Neuroimmune communication is one of the key components in regulating the body’s response to physiological challenges and maintaining homeostasis while facilitating immune stress response. Within the gastrointestinal tract, the mesenteric lymph nodes play a key role in governing the immune response, and this regulation involves communication between immune cells and neural components.Sympathetic neurons are thought to co-release norepinephrine and dopamine to modulate cytokine signaling during inflammation and therefore measurements of these neurochemicals in the lymph node are critical for understanding immunity. Here, we have expanded our electrochemical waveform and way of performing the experiment in ex vivo lymph node slices to study how these neurochemicals communicate in the lymph node during different conditions. We have also tried blocking the different neurotransmitter transporter with different antagonist drugs for different catecholamines to see the differential change and came to know that these transport blockers have significant effect on holding the neurochemical in the extracellular space when we block their transporter. This work presents the first-time detection on role of different transport blocker and their impact in the mechanism of catecholamine release in the MLN on a millisecond timescale, which will provide significant insight into the mechanisms of neuron-immune communication and different drug related studies.​

Computed tomography benefits and cost in hemodynamically stable patients with blunt abdominal trauma at an Egyptian University Hospital

BackgroundTrauma is a significant cause of mortality, especially among individuals aged between 15 and 44 years, with a substantial burden falling on economically active populations. Low- and middle-income countries (LMICs) bear the burden of trauma-related deaths, accounting for over 90 % globally. In Egypt, trauma rates are increasing, primarily due to road traffic crashes (RTC), affecting males disproportionately. Blunt abdominal trauma, often caused by RTC, can lead to missed intra-abdominal injuries (IAIs) due to atypical symptoms. Computed Tomography (CT) offers high sensitivity and specificity in detecting IAIs, but concerns about cost and radiation exposure exist. MethodologyThis study investigates the roles of Focused Assessment with Sonography for Trauma (FAST) and CT in managing blunt abdominal trauma. A retrospective cohort study was conducted on hemodynamically stable patients. Data included patient demographics, trauma details, healthcare decisions, costs, and outcomes. ResultsComputed tomography significantly reduced unnecessary laparotomies (12.3% vs. 24.8 %, p = 0.001), shortened hospital stays (4.83±0.71 days vs. 6.15±1.28 days, p = 0.005), and reduced ICU admissions (8 vs. 32, p = 0.023) compared to FAST alone. Overall costs were lower in the CT & FAST Group ($2055.95 vs. $3488.7, p = 0.0001), with no significant difference in missed IAIs. ConclusionThis study highlights the limitations of relying solely on FAST for IAIs and underscores the value of CT in guiding healthcare decisions. Incorporating CT led to reduced negative laparotomies, shorter hospital stays, and fewer ICU admissions. While CT incurs initial costs, its long-term benefits outweigh expenditures, particularly in LMICs. This study provides insights into optimizing diagnostic approaches for blunt abdominal trauma in low-resource settings.

Fragility crossover mediated by covalent-like electronic interactions in metallic liquids

Abstract Fragility is one of the central concepts in glass and liquid sciences, as it characterizes the extent of deviation of viscosity from Arrhenius behavior and is linked to a range of glass properties. However, the intervention of crystallization often prevents the assessment of fragility in poor glass-formers, such as supercooled metallic liquids. Hence experimental data on their compositional dependence are scarce, let alone fundamentally understood. In this work, we use fast scanning calorimetry to overcome this obstacle and systematically study the fragility in a ternary La-Ni-Al system, over previously inaccessible composition space. We observe fragility dropped in a small range with the Al alloying, indicating an alloying-induced fragility crossover. We use x-ray photoelectron spectroscopy, resistance measurements, electronic structure calculations, and DFT-based deep-learning atomic simulations to investigate the cause of this fragility drop. These results show that the fragility crossover can be fundamentally ascribed to the electronic covalency associated with the unique Al-Al interactions. Our findings provide insight into the origin of fragility in metallic liquids from an electronic structure perspective and pave a new way for the design of metallic glasses.

A new experimental setup for combined fast differential scanning calorimetry and X-ray photon correlation spectroscopy.

Synchrotron-radiation-based techniques are a powerful tool for the investigation of materials. In particular, the availability of highly brilliant sources has opened the possibility to develop techniques sensitive to dynamics at the atomic scale such as X-ray photon correlation spectroscopy (XPCS). XPCS is particularly relevant in the study of glasses, which have been often investigated at the macroscopic scale by, for example, differential scanning calorimetry. Here, we show how to adapt a Flash calorimeter to combine XPCS and calorimetric scans. This setup paves the way to novel experiments requiring dynamical and thermodynamic information, ranging from the study of the crystallization kinetics to the study of the glass transition in systems that can be vitrified thanks to the high cooling rates reachable with an ultrafast calorimeter.

Awake pediatric brain-MRI: a fast multi-sequence scan augmented with motion compensated single-shot 2D acquisitions

Abstract Background Magnetic resonance imaging (MRI) is susceptible to motion artifacts, a particular challenge in pediatric imaging. External motion tracking devices and navigator techniques have been previously explored, but challenges persist necessitating sedation. Purpose To establish a new awake brain-MRI exam tolerated by children with diagnostic quality images. Materials and Methods Participants were prospectively recruited and investigated using an in-house developed multi-sequence scan called NeuroMix that produces T1-weighted, T2-weighted, T2*-weighted, T2-FLAIR, and diffusion-weighted images in under 3 minutes. Additionally, a self-created motion tracking device was attached to participants' foreheads to perform prospective motion correction (PMC) on 2D single-shot sequences that produce higher resolution images of the same contrasts as NeuroMix. Three neuroradiologists scored the completed series for artifacts. The effects of age group (&amp;lt;5 vs ≥5 years) and sequence type (NeuroMix vs PMC) were evaluated with a Chi2-test. Results Of the 64 participants recruited (mean age 6.7 years [2.7 standard deviation]) 58 completed their examination. Head motion recorded during PMC sequences revealed prevalent superior-inferior displacements [25% (67/293) exceeding 13.2 mm], and chin-up/down rotations [25% (67/293) exceeding 13.7°]. Sequence redundancy through NeuroMix and PMC scans resulted in 93% (54/58) of completed examinations having all series essential for producing an MRI-report rated as artifact-free, and therefore a report of high confidence in 84% (54/64) of participants. 22% (13/58) of completed exam reports could have been written using NeuroMix alone, the remaining required PMC- T2-weighted or T2-FLAIR sequences. Conclusion This protocol reliably provided diagnostic quality images and reports with high radiologist confidence and could reduce the use of procedure sedation in children.

Fast SPECT/CT planar bone imaging enabled by deep learning enhancement.

The application of deep learning methods in rapid bone scintigraphy is increasingly promising for minimizing the duration of SPECT examinations. Recent works showed several deep learning models based on simulated data for the synthesis of high-count bone scintigraphy images from low-count counterparts. Few studies have been conducted and validated on real clinical pairs due to the misalignment inherent in multiple scan procedures. To generate high quality whole-body bone images from 2× and 3× fast scans using deep learning based enhancement method. Seventy-six cases who underwent whole-body bone scans were enrolled in this prospective study. All patients went through a standard scan at a speed of 20cm/min, which followed by fast scans consisting of 2× and 3× accelerations at speeds of 40 and 60cm/min. A content-attention image restoration approach based on Residual-in-Residual Dense Block (RRDB)is introduced to effectively recover high-quality images from fast scans with fine-details and less noise. Our approach is robust with misalignment introduced from patient's metabolism, and shows valid count-level consistency. Learned Perceptual Image Patch Similarity (LPIPS) and Fréchet Inception Distance (FID) are employed in evaluating the similarity to the standard bone images. To further prove our method practical in clinical settings, image quality of the anonymous images was evaluated by two experienced nuclear physicians on a 5-point Likert scale (5= excellent). The proposed method reaches the state-of-the-art performance on FID and LPIPS with 0.583 and 0.176 for 2× fast scans and 0.583 and 0.185 for 3× fast scans. Clinic evaluation further demonstrated the restored images had a significant improvement compared to fast scan in image quality, technetium 99m-methyl diphosphonate (Tc-99m MDP) distribution, artifacts, and diagnostic confidence. Our method was validated for accelerating whole-body bone scans by introducing real clinical data. Confirmed by nuclear medicine physicians, the proposed method can effectively enhance image diagnostic value, demonstrating potential for efficient high-quality fast bone imaging in practical settings.

Phase transition thermodynamics of organic semiconductors: N,N,N’,N’-tetraphenylbenzidine and 4,4′-bis(N-carbazolyl)-1,1′-biphenyl

In this work, we report a comprehensive study of the phase change thermodynamics of two compounds, N,N,N’,N’-tetraphenylbenzidine (TPB) and 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), used in the production of organic light-emitting diodes and photovoltaics. The vapor pressures and phase transition enthalpies of these compounds have been previously studied at the elevated temperatures which may not be relevant to the conditions during fabrication and use TPB- and CBP-based materials. In this work, a combination of experimental and computational methods was employed to establish the reliable temperature dependences of the sublimation, fusion, and vaporization enthalpies of TPB and CBP in a wide temperature range. The vapor pressures of both compounds over solid and liquid phases were measured using fast scanning calorimetry. The fusion enthalpies at the melting point were determined by DSC. The isobaric heat capacities of the compounds in crystalline and liquid phases, including the supercooled liquids, were measured using scanning calorimetry. For the first time, the heat capacities of the ideal gas TPB and CBP were computed, considering internal rotation effects. The solution enthalpies in benzene at 298.15 K were measured, providing an independent estimate of the fusion enthalpy temperature dependence. Its consistency with the data on the fusion enthalpies was confirmed using Hess’s and Kirchhoff’s laws of Thermochemistry. Using the obtained results, the available literature data were critically evaluated. The obtained thermodynamic parameters may facilitate optimization of vapor deposition conditions and description of the thermodynamic and kinetic stability of the glassy state of TPB and CBP.

Pediatric Emergency Medicine Ultrasound Fellowship Programs.

Point of care ultrasound (POCUS) has undergone important growth in the field of Pediatric Emergency Medicine (PEM) in the last 14 years and is recognized as a critical diagnostic tool in the care of ill and injured children. The first PEM POCUS fellowship was established in 2010. Now, there are currently 30 ultrasound fellowships that offer training to PEM physicians. In 2014, 46 PEM POCUS leaders established the P2 (PEM POCUS) Network (www.P2network.org). This serves as a platform for sharing expertise, building research collaborations, and offering mentorship in the use of POCUS in PEM. In 2019, a multinational group of experts in PEM POCUS published the first consensus guidelines for prioritizing core applications of POCUS, which are fundamental to PEM fellowship training 1. In 2022, the international research priorities for PEM POCUS were published 2. In the same year, the development of a consensus-based definition of focused assessment with sonography for trauma (FAST) in children was established 3.

T staging esophageal tumors with x rays.

With histopathology results typically taking several days, the ability to stage tumors during interventions could provide a step change in various cancer interventions. X-ray technology has advanced significantly in recent years with the introduction of phase-based imaging methods. These have been adapted for use in standard labs rather than specialized facilities such as synchrotrons, and approaches that enable fast 3D scans with conventional x-ray sources have been developed. This opens the possibility to produce 3D images with enhanced soft tissue contrast at a level of detail comparable to histopathology, in times sufficiently short to be compatible with use during surgical interventions. In this paper we discuss the application of one such approach to human esophagi obtained from esophagectomy interventions. We demonstrate that the image quality is sufficiently high to enable tumor staging based on the x-ray datasets alone. Alongside detection of involved margins with potentially life-saving implications, staging tumors intra-operatively has the potential to change patient pathways, facilitating optimization of therapeutic interventions during the procedure itself. Besides a prospective intra-operative use, the availability of high-quality 3D images of entire esophageal tumors can support histopathological characterization, from enabling "right slice first time" approaches to understanding the histopathology in the full 3D context of the surrounding tumor environment.

Isothermal crystallization of polyethylene droplets within the self-nucleated isotactic polypropylene matrix of a 70/30 iPP/PE immiscible blend via fast scanning chip calorimetry (FSC)

The escalating volume of waste related to polyolefins poses recycling challenges. Given the mixed composition of the post-consumer feedstock, studying blends of virgin polyolefins is a fruitful strategy to simulate such compositions. For the first time, this study investigates crystallization, self-nucleation (SN), and kinetics of a 70/30 iPP/PE blend, characterised by a "sea-island" morphology, using fast scanning calorimetry (FSC). Preliminary experiments on different chip sensors proved the technique's sensitivity and representativeness for polymer blends, even with minimal sample quantities. Application of the self-nucleation thermal protocol (employing fast scanning rates, from 500 to 1000 °C/s) to the iPP matrix phase revealed insights into the characteristic SN domains. The crystallization kinetics of PE-dispersed droplets within a SN iPP matrix was also investigated. Results indicate a 30 °C crystallization window for PE droplets within the self-nucleated iPP matrix, expanding the understanding of crystallization rates (up to four decades) compared to standard DSC measurements.

Influence of Chemical Composition and Structure on the Cooperative Fluctuation in Supercooled Glass-Forming Liquids.

The kinetics of the glass transition and the characteristic size of the fluctuating spatio-temporal domains in supercooled glass-forming liquids, i.e., the Cooperatively Rearranging Regions (CRR), were measured upon cooling over a broad range of cooling rates using Differential Scanning Calorimetry (DSC) and chip-based Fast Scanning Calorimetry (FSC). The investigations were conducted on a selection of fragile glass formers (fragility indices between 80 and 140), with a large variance in the atomic or molecular structure but comparable thermal glass transition temperatures Tg, with the aim of evaluating the influence of chemical composition and structure on the CRR size and the associated temperature fluctuation. The selected materials are two polymers (poly(vinyl acetate) (PVAc), poly(lactic acid) (PLA)) as well as the simplest chalcogenide glass-former (selenium). It turned out that the CRR size plotted against the reduced temperature T/Tg follows the same trend, irrespective of the considered glass-former.

Exploring the effect of cooling rate on non-isothermal crystallization of copolymer polypropylene by fast scanning calorimetry

Exploring the effect of cooling rate on non-isothermal crystallization of copolymer polypropylene by fast scanning calorimetry