Variation Of Signal Intensity Research Articles

Spinning Disk Confocal Microscopy for Optimized and Quantified Live Imaging of 3D Mitochondrial Network.

Mitochondria are the energy factories of a cell, and depending on the metabolic requirements, the mitochondrial morphology, quantity, and membrane potential in a cell change. These changes are frequently assessed using commercially available probes. In this study, we tested the suitability of three commercially available probes-namely 5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolo-carbocyanine iodide (JC-1), MitoTracker Red CMX Rox (CMXRos), and tetramethylrhodamine methyl ester (TMRM)-for assessing the mitochondrial quantity, morphology, and membrane potential in living human mesoangioblasts in 3D with confocal laser scanning microscope (CLSM) and scanning disk confocal microscope (SDCM). Using CLSM, JC-1, and CMXRos-but not TMRM-uncovered considerable background and variation. Using SDCM, the background signal only remained apparent for the JC-1 monomer. Repetitive imaging of CMXRos and JC-1-but not TMRM-demonstrated a 1.5-2-fold variation in signal intensity between cells using CLSM. The use of SDCM drastically reduced this variation. The slope of the relative signal intensity upon repetitive imaging using CLSM was lowest for TMRM (-0.03) and highest for CMXRos (0.16). Upon repetitive imaging using SDCM, the slope varied from 0 (CMXRos) to a maximum of -0.27 (JC-1 C1). Conclusively, our data show that TMRM staining outperformed JC-1 and CMXRos dyes in a (repetitive) 3D analysis of the entire mitochondrial quantity, morphology, and membrane potential in living cells.

Comprehensive analysis of synthetic learning applied to neonatal brain MRI segmentation.

Brain segmentation from neonatal MRI images is a very challenging task due to large changes in the shape of cerebral structures and variations in signal intensities reflecting the gestational process. In this context, there is a clear need for segmentation techniques that are robust to variations in image contrast and to the spatial configuration of anatomical structures. In this work, we evaluate the potential of synthetic learning, a contrast-independent model trained using synthetic images generated from the ground truth labels of very few subjects. We base our experiments on the dataset released by the developmental Human Connectome Project, for which high-quality images are available for more than 700 babies aged between 26 and 45 weeks postconception. First, we confirm the impressive performance of a standard UNet trained on a few volumes, but also confirm that such models learn intensity-related features specific to the training domain. We then confirm the robustness of the synthetic learning approach to variations in image contrast. However, we observe a clear influence of the age of the baby on the predictions. We improve the performance of this model by enriching the synthetic training set with realistic motion artifacts and over-segmentation of the white matter. Based on extensive visual assessment, we argue that the better performance of the model trained on real T2w data may be due to systematic errors in the ground truth. We propose an original experiment allowing us to show that learning from real data will reproduce any systematic bias affecting the training set, while synthetic models can avoid this limitation. Overall, our experiments confirm that synthetic learning is an effective solution for segmenting neonatal brain MRI. Our adapted synthetic learning approach combines key features that will be instrumental for large multisite studies and clinical applications.

Nondestructive measurement of the capillary water absorption coefficient and water transport behaviors of porous building materials by using single-sided NMR

Capillarity has an important effect on the durability of buildings, and the capillary absorption coefficient is a key parameter to describe the strength of material capillarity. Most of the methods currently used to measure the capillary absorption coefficient of materials can damage the sample or are not accurate enough and need to be improved. This paper proposes a method to measure the capillary absorption coefficient of brick, sandstone, mortar and concrete by using a single-sided nuclear magnetic resonance (NMR) technique, which has the advantages of accuracy, nondestructiveness, continuity and rapidity. The relative error of the capillary absorption coefficient obtained from three repetitions of the experiment ranges from 0 to 5.11%, which is in the range of 0.64%∼1.30% compared with that obtained by the partial impregnation method. This method has great potential for application in in situ testing. This paper also analyzed the water transport behaviors in porous building materials based on the variation in NMR signal intensity in the measured materials and established a water transport model. The model is divided into two stages: the first stage is mainly the one-dimensional rise in moisture in the vertical direction. The second stage is mainly the diffusion of moisture in the horizontal direction, which continuously fills each pore space to saturation. Difficulty in removing air leads to a reduced rate of water absorption in the second stage.

Identifying Seismic Anomalies via Wavelet Maxima Analysis of Satellite Microwave Brightness Temperature Observations

This study develops a wavelet maxima-based methodology to extract anomalous signals from microwave brightness temperature (MBT) observations for seismogenic activity. MBT, acquired via satellite microwave radiometry, enables subsurface characterization penetrating clouds. Five surface categories of the epicenter area were defined contingent on position (oceanic/terrestrial) and ambient traits (soil hydration, vegetal covering). Continuous wavelet transform was applied to preprocess annualized MBT readings preceding and succeeding prototypical events of each grouping, utilizing optimized wavelet functions and orders tailored to individualized contexts. Wavelet maxima graphs visually portraying signal intensity variations facilitated the identification of aberrant phenomena, including pre-seismic accrual, co-seismic perturbation, and postseismic remission signatures. The casework found 10 GHz horizontal-polarized MBT optimally detected signals for aquatic and predominantly humid/vegetative settings, whereas 36 GHz horizontal-polarized performed best for arid, vegetated landmasses. Quantitative machine learning methods are warranted to statistically define selection standards and augment empirical forecasting leveraging lithospheric stress state inferences from sensitive MBT parametrization.

Current MR imaging of cartilage in the context of knee osteoarthritis (part2) : Cartilage pathologies and their assessment

High-quality magnetic resonance (MR) imaging is essential for the precise assessment of the knee joint and plays a key role in the diagnostics, treatment and prognosis. Intact cartilage tissue is characterized by asmooth surface, uniform tissue thickness and an organized zonal structure, which are manifested as depth-dependent signal intensity variations. Cartilage pathologies are identifiable through alterations in signal intensity and morphology and should be communicated based on a precise terminology. Cartilage pathologies can show hyperintense and hypointense signal alterations. Cartilage defects are assessed based on their depth and should be described in terms of their location and extent. The following symptom constellations are of overarching clinical relevance in image reading and interpretation: symptom constellations associated with rapidly progressive forms of joint degeneration and unfavorable prognosis, accompanying symptom constellations mostly in connection with destabilizing meniscal lesions and subchondral insufficiency fractures (accelerated osteoarthritis) as well as symptoms beyond the "typical" degeneration, especially when adiscrepancy is observed between (minor) structural changes and (major) synovitis and effusion (inflammatory arthropathy).

Ectoparasite load generates habitat-specific variation in colour badge intensity and badge size in male lizards

Abstract The severity of parasitic infections can mediate the differential expression of signals among populations, creating variation in signal intensity. Male signals (patch size and brightness) were quantified in Florida scrub lizards (Sceloporus woodi) from populations that vary in ectoparasite load. Males without mites were caught before breeding and exhibited different correlations among body size, patch size, and brightness. Males with ectoparasites (range = 1–368) were captured throughout the breeding season and showed a habitat-dependent pattern of how ectoparasite load, body size, and body condition were correlated with badge characteristics. In the sand pine scrub habitat, large males in good condition that were heavily parasitized had the largest badges. There was no relationship between body size or ectoparasite load and badge darkness. Lizards from longleaf pine habitat shared only one pattern, i.e. larger males had larger badges, yet there were several key differences. Body condition and ectoparasite load were unrelated to badge size, and the most heavily parasitized males had the brightest, not darkest, badges. Instead, males with moderate and low parasite loads had the darkest abdomens, and those with low parasite loads had the darkest throats. Thus, parasite load and body condition have habitat-dependent effects on badge characteristics.

Kiosk 6R-FB-09 - Cine Balanced Steady-state FBee Precession Signal Intensity Variations in Healthy Myocardium

Kiosk 6R-FB-09 - Cine Balanced Steady-state FBee Precession Signal Intensity Variations in Healthy Myocardium

Use of MR signal intensity variations to highlight structures at risk along brain biopsy trajectories.

Postoperative intracerebral hemorrhages are significant complications following brain stereotactic biopsy. They can derive from anatomical structure (sulci, vessels) damage that is missed during stereotactic trajectory planning. In this study, the authors investigated the ability to detect contact between structures at risk and stereotactic trajectories using signal analysis from MRI obtained during clinical practice, with the aim to propose a visual tool to highlight areas with anatomical structures at risk of damage along the biopsy trajectory. The authors retrospectively analyzed actual stereotactic trajectories using intraoperative imaging (intraoperative 2D radiographs in the exploratory data set and intraoperative 3D scans in the confirmatory data set). The MR signal variation along each biopsy trajectory was matched with the patient's anatomy. In the exploratory data set (n = 154 patients), 32 contacts between the actual biopsy trajectory and an anatomical structure at risk were identified along 28 (18.2%) biopsy trajectories, corresponding to 8 preventable intracerebral hemorrhages. Variations of the mean derivative of the MR signal intensity were significantly different between trajectories with and without contact (the pathological threshold of the mean derivative of the MR signal intensity was defined as ± 0.030 arbitrary units; p < 0.0001), with a sensitivity of 89.3% and specificity of 74.6% to detect a contact. In the confirmatory data set (n = 73 patients), the sensitivity and specificity of the 0.030 threshold to detect a contact between the actual stereotactic trajectory and an anatomical structure at risk were 81.3% and 68.4%, respectively. Variations of the mean derivative of the MR signal intensity can be converted into a green/red color code along the planned biopsy trajectory to highlight anatomical structures at risk, which can help neurosurgeons during the surgical planning of stereotactic procedures.

In-Situ Spectroscopic Investigation of 3-D Gas Diffusion Electrodes for Fuel Cell Reactions in Half-Cell Setups

Significant work has already been done in understanding proton exchange membrane fuel cells (PEMFC) over the past decades. In-situ visualization of the fuel-cell reactions has developed considerably and has also helped in understanding the challenges which still exist in various steps of electrochemical processing. Gas diffusion electrode half-cells have been widely promoted for fundamental catalysis research and when coupled with techniques like X-ray absorption spectroscopy (XAS) can be used for in-situ/operando studies of the reaction mechanisms in fuel cell reactions. This is particularly important to address the challenges in low temperature PEMFCs (eg. degradation of catalyst during durability tests) as well as high temperature PEMFCs (eg. poisoning of the Pt catalyst and low oxygen solubility in phosphoric acid).In this presentation, an effort will be made to illuminate the catalytic characteristics during oxygen reduction reaction using in-situ XAS. The co-adsorption of H3PO3 and CO on platinum catalysts will be investigated using the Δµ XANES technique by following the signatures of different species adsorbed on the catalyst surface, and the Efix technique which follows the variation of signal intensity at a fixed energy near to the white line to follow the changes in Pt oxidation. During CO removal through cyclic voltammetry in the presence of 800 µM H3PO3 (as shown in the figure provided) it is possible to see a clear change in signal intensity around the potential of 250 mVAg/AgCl, which was associated with the oxidation of H3PO3 to H3PO4, since CO oxidation takes place at higher potentials (above 600 mVAg/AgCl). It is also interesting to note that when oxidizing H3PO3 to H3PO4, the platinum surface significantly reduced. With these experiments, it can be concluded that the Efix technique has a great potential to better understand what happens to Pt during the oxidation of H3PO3, as well as to identify more clearly the oxidation potential of this species, which is not easy to do based on the electrochemical data alone. Considering that this species is one of the main species responsible for the poisoning of the Pt catalyst during the operation of fuel cells, it is extremely important to understand the life cycle of this compound so that the operating conditions can be adapted to maximize the performance of the catalyst and develop new catalysts more resistant to poisoning by phosphorous species for HT-PEMFCs.Acknowledgements:Prof. Matthias Arenz from University of Bern, Martin Prokopand Tomàs Bystrom from University of Chemistry and Technology Prague, Michael Haumann, Freie Universität Berlin are gratefully thanked for their collaboration. German Research Foundation DFG Project ID RO 2454/19-1, the Bavarian Gender Equality Grant 2019-2021 (for Women in Academia), Petra III DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, P65 beamline (I-20211432) and KMC-3 beamline BESSY (Berlin,Germany). Figure 1

Estimation of Thermal Stability of Si-SiO2-W Nanolayered Structures with Infrared Spectrometry.

Nanolayered coatings are proposed for use in microelectronic devices where the size/performance ratio is becoming increasingly important, with the aim to achieve existing quality requirements while reducing the size of the devices and improving their ability to perform stably over multiple cycles. Si-SiO2-W structures have been proposed as a potential material for the fabrication of microelectronic devices. However, before such materials can be implemented in devices, their properties need to be carefully studied. In this study, Si-SiO2-W nanolayered structures were fabricated and subjected to numerous thermal treatment cycles at 150 °C. A total of 33 heating cycles were applied, resulting in a cumulative exposure of 264 h. The changes in chemical bonds and microstructure were monitored using Fourier Transform Infrared spectrometry (FTIR) and scanning electron microscopy (SEM). The FTIR signal at 960 cm-1, indicating the presence of W deposited on SiO2, was selected to characterize the thermal stability during the heating cycles. The estimated signal intensity variation closely resembled the normal inhomogeneity of the nanolayers. The increase in slope intensity was estimated to be 1.7 × 10-5.

Measurement of Abdominal Aortic Aneurysm Strain Using MR Deformable Image Registration: Accuracy and Relationship to Recent Aneurysm Progression.

Management of asymptomatic abdominal aortic aneurysm (AAA) based on maximum aneurysm diameter and growth rate fails to preempt many ruptures. Assessment of aortic wall biomechanical properties may improve assessment of progression and rupture risk. This study aimed to assess the accuracy of AAA wall strain measured by cine magnetic resonance imaging (MRI) deformable image registration (MR strain) and investigate its relationship with recent AAA progression. The MR strain accuracy was evaluated in silico against ground truth strain in 54 synthetic MRIs generated from a finite element model simulation of an AAA patient's abdomen for different aortic pulse pressures, tissue motions, signal intensity variations, and image noise. Evaluation included bias with 95% confidence interval (CI) and correlation analysis. Association of MR strain with AAA growth rate was assessed in 25 consecutive patients with >6 months of prior surveillance, for whom cine balanced steady-state free-precession imaging was acquired at the level of the AAA as well as the proximal, normal-caliber aorta. Univariate and multivariate regressions were used to associate growth rate with clinical variables, maximum AAA diameter (D max ), and peak circumferential MR strain through the cardiac cycle. The MR strain interoperator variability was assessed using bias with 95% CI, intraclass correlation coefficient, and coefficient of variation. In silico experiments revealed an MR strain bias of 0.48% ± 0.42% and a slope of correlation to ground truth strain of 0.963. In vivo, AAA MR strain (1.2% ± 0.6%) was highly reproducible (bias ± 95% CI, 0.03% ± 0.31%; intraclass correlation coefficient, 97.8%; coefficient of variation, 7.14%) and was lower than in the nonaneurysmal aorta (2.4% ± 1.7%). D max ( β = 0.087) and MR strain ( β = -1.563) were both associated with AAA growth rate. The MR strain remained an independent factor associated with growth rate ( β = -0.904) after controlling for D max . Deformable image registration analysis can accurately measure the circumferential strain of the AAA wall from standard cine MRI and may offer patient-specific insight regarding AAA progression.

3D Brain Tumour Segmentation Using UNet with Quantitative Analysis of the Tumour Features

Brain tumours are abnormal cells that grow within the brain and may cause severe harm to an individual. The diagnosis of tumours often requires a manual review of Magnetic Resonance (MR) images by a skilled radiologist, which is a laborious task. The study aims to use a deep learning-based approach to segment the brain tumour and quantitatively evaluate the performance of the model by comparing the statistical distribution of five textural and four non-textural feature differences between the ground truth and the prediction. Textural features were extracted from a Grey Level Co-occurrence Matrix (GLCM) and averaged over four different directions. A UNet model was constructed with MONAI using BraTS 2020 dataset. Due to hardware constraints, the model was trained over a short epoch range of 100 but managed to achieve a mean Dice similarity coefficient (DSC) of 0.86. The quantitative analysis showed that the ground truth and the prediction had low differences in most features, except for percentage variation in signal intensity, energy, correlation and Hausdorff distance, which could be attributed to false positive voxels that are far from the ground truth. The textural properties of homogeneity, entropy, and correlation had an average absolute percentage difference of less than 5% from the ground truth.

Delineation and detection of breast cancer using novel label-free fluorescence

BackgroundAccurate diagnosis of breast cancer (BC) plays a crucial role in clinical pathology analysis and ensuring precise surgical margins to prevent recurrence.MethodsLaser-induced fluorescence (LIF) technology offers high sensitivity to tissue biochemistry, making it a potential tool for noninvasive BC identification. In this study, we utilized hyperspectral (HS) imaging data of stimulated BC specimens to detect malignancies based on altered fluorescence characteristics compared to normal tissue. Initially, we employed a HS camera and broadband spectrum light to assess the absorbance of BC samples. Notably, significant absorbance differences were observed in the 440–460 nm wavelength range. Subsequently, we developed a specialized LIF system for BC detection, utilizing a low-power blue laser source at 450 nm wavelength for ten BC samples.ResultsOur findings revealed that the fluorescence distribution of breast specimens, which carries molecular-scale structural information, serves as an effective marker for identifying breast tumors. Specifically, the emission at 561 nm exhibited the greatest variation in fluorescence signal intensity for both tumor and normal tissue, serving as an optical predictive biomarker. To enhance BC identification, we propose an advanced image classification technique that combines image segmentation using contour mapping and K-means clustering (K-mc, K = 8) for HS emission image data analysis.ConclusionsThis exploratory work presents a potential avenue for improving "in-vivo" disease characterization using optical technology, specifically our LIF technique combined with the advanced K-mc approach, facilitating early tumor diagnosis in BC.

Modulatable all-optical logic gate in rubidium atoms using OAM

We experimentally demonstrate the intensity and angle control of interference image during all-optical logic (AOL) gate carrying orbital angular momentum (OAM) in a hot atomic ensemble. The variation of output signal intensity has been discovered by changing the detuning of input field. By changing the angle of reference light, we can also get obvious output signal modulation effects. Moreover, the transition of the interference pattern from parallel shape to spiral shape by changing the small angle is observed. This novel method of controlling AOL gate carrying OAM will further promoting the construction of all-optical networks with atomic ensembles.

Tracking Permeation of Dimethyl Sulfoxide (DMSO) in Mentha × piperita Shoot Tips Using Coherent Raman Microscopy.

Cryopreservation has emerged as a low-maintenance, cost-effective solution for the long-term preservation of vegetatively propagated crops. Shoot tip cryopreservation often makes use of vitrification methods that employ highly concentrated mixtures of cryoprotecting agents; however, little is understood as to how these cryoprotecting agents protect cells and tissues from freezing. In this study, we use coherent anti-Stokes Raman scattering microscopy to directly visualize where dimethyl sulfoxide (DMSO) localizes within Mentha × piperita shoot tips. We find that DMSO fully penetrates the shoot tip tissue within 10 min of exposure. Variations in signal intensities across images suggest that DMSO may interact with cellular components, leading to its accumulation in specific regions.

Multi-Level Logarithmic Amplification-Based Fixed Threshold Circular Polarized On-Off Keying Detection for Free-Space Optical Communications

This study investigates a multi-level logarithmic amplification (MLA)-based fixed threshold circular polarized on-off keying (CP-OOK) detection for free-space optical (FSO) communication links. OOK signal is polarized into a single circular polarization state by a linear polarizer (LP) and a quarter-wave plate (QWP). In the receiver terminal, firstly, circular polarization is transformed into linear polarization utilizing QWP without polarization coordinates alignment between transmitter and receiver. Then, the background noises are decreased by polarization filtering using LP. Then, CP-OOK signal intensity variation is eliminated by nonlinear gains from MLAs in the low gain nonlinearity condition. Finally, fixed threshold decision (FTD) is realized by optimizing cascaded LAs to reduce the extinction ratio distortion of the CP-OOK signal. The proposed CP-OOK transmission is analyzed under various strengths of turbulence channel and different configurations of MLAs. Simulation results demonstrated that the proposed CP-OOK signal was effectively detected by FTD with optimized MLAs.

Non-Contrast-Enhanced Functional Lung MRI to Evaluate Treatment Response of Allergic Bronchopulmonary Aspergillosis in Patients With Cystic Fibrosis: A Pilot Study.

Allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients is associated with severe lung damage and requires specific therapeutic management. Repeated imaging is recommended to both diagnose and follow-up response to treatment of ABPA in CF. However, high risk of cumulative radiation exposure requires evaluation of free-radiation techniques in the follow-up of CF patients with ABPA. To evaluate whether Fourier decomposition (FD) functional lung MRI can detect response to treatment of ABPA in CF patients. Retrospective longitudinal. Twelve patients (7M, median-age:14 years) with CF and ABPA with pre- and post-treatment MRI. 2D-balanced-steady-state free-precession (bSSFP) sequence with FD at 1.5T. Ventilation-weighted (V) and perfusion-weighted (Q) maps were obtained after FD processing of 2D-coronal bSSFP time-resolved images acquired before and 3-9 months after treatment. Defects extent was assessed on the functional maps using a qualitative semi-quantitative score (0 = absence/negligible, 1 = <50%, 2 = >50%). Mean and coefficient of variation (CV) of the ventilation signal-intensity (VSI) and the perfusion signal-intensity (QSI) were calculated. Measurements were performed independently by three readers and averaged. Inter-reader reproducibility of the measurements was assessed. Pulmonary function tests (PFTs) were performed within 1 week of both MRI studies as markers of the airflow-limitation severity. Comparisons of medians were performed using the paired Wilcoxon-test. Reproducibility was assessed using intraclass correlation coefficient (ICC). Correlations between MRI and PFT parameters were assessed using the Spearman-test (rho correlation-coefficient). A P-value <0.05 was considered as significant. Defects extent on both V and Q maps showed a significant reduction after ABPA treatment (4.25 vs. 1.92 for V-defect-score and 5 vs. 2.75 for Q-defect-score). VSI_mean was significantly increased after treatment (280 vs. 167). Qualitative analyses reproducibility showed an ICC > 0.90, while the ICCs of the quantitative measurements was almost perfect (>0.99). Changes in VSI_cv and QSI_cv before and after treatment correlated inversely with changes of FEV1%p (rho = -0.68 for both). Non-contrast-enhanced FD lung MRI has potential to reproducibly assess response to treatment of ABPA in CF patients and correlates with PFT obstructive parameters. 4 TECHNICAL EFFICACY: Stage 3.

Investigating structural attributes of drug encapsulated microspheres with quantitative X-ray imaging.

The intra-sphere and inter-sphere structural attributes of controlled release microsphere drug products can greatly impact their release profile and clinical performance. In developing a robust and efficient method to characterize the structure of microsphere drug products, this paper proposes X-ray microscopy (XRM) combined with artificial intelligence (AI)-based image analytics. Eight minocycline loaded poly(lactic-co-glycolic acid) (PLGA) microsphere batches were produced with controlled variations in manufacturing parameters, leading to differences in their underlying microstructures and their final release performances. A representative number of microspheres samples from each batch were imaged using high resolution, non-invasive XRM. Reconstructed images and AI-assisted segmentation were used to determine the size distribution, XRM signal intensity, and intensity variation of thousands of microspheres per sample. The signal intensity within the eight batches was nearly constant over the range of microsphere diameters, indicating high structural similarity of spheres within the same batch. Observed differences in the variation of signal intensity between different batches suggests inter-batch non-uniformity arising from differences in the underlying microstructures associated with different manufacturing parameters. These intensity variations were correlated with the structures observed from higher resolution focused ion beam scanning electron microscopy (FIB-SEM) and the in vitro release performance for the batches. The potential for this method for rapid at-line and offline product quality assessment, quality control, and quality assurance is discussed.

Two-Color-Thermography for Temperature Determination in Laser Beam Welding of Low-Melting Materials.

Spatial and temporal knowledge of temperature evolution is crucial in laser beam welding of low-melting materials such as aluminum alloys. Current temperature measurements are restricted to (i) one-dimensional temperature information (e.g., ratio-pyrometers), (ii) a priori knowledge of emissivity (e.g., thermography), and (iii) high-temperature regions (e.g., two-color-thermography). This study presents a ratio-based two-color-thermography system that enables acquiring spatially and temporally resolved temperature information for low-melting temperature ranges (<1200 K). The study demonstrates that temperature can be accurately determined despite variations in signal intensity and emissivity for objects emitting constant thermal radiation. The two-color-thermography system is further transferred into a commercial laser beam welding set-up. Experiments with varying process parameters are conducted, and the ability of the thermal imaging method to measure dynamic temperature behavior is assessed. Image artifacts presumably caused by internal reflections inside the optical beam path limit the direct application of the developed two-color-thermography system during dynamic temperature evolution.

New calibration setup for quantitative DCE-US imaging protocol: Toward standardization.

The DCE-US (Dynamic Contrast-Enhanced Ultrasonography) imaging protocol predicts the vascular modifications compared with Response Evaluation Criteria in Solid Tumors (RECIST) based mainly on morphological changes. A quantitative biomarker has been validated through the DCE-US multi-centric study for early monitoring of the efficiency of anti-angiogenic cancer treatments. In this context, the question of transposing the use of this biomarker to other types of ultrasound scanners, probes and settings has arisen to maintain the follow-up of patients under anti-angiogenic treatments. As a consequence, radiologists encounter standardization issues between the different generations of ultrasound scanners to perform quantitative imaging protocols. The aim of this study was to develop a new calibration setup to transpose the DCE-US imaging protocol to the new generation of ultrasound scanners using both abdominal and linear probes. This calibration method has been designed to be easily reproducible and optimized, reducing the time required and cost incurred. It is based on an original set-up that includes using a concentration splitter to measure the variation of the harmonic signal intensity, obtained from the Area Under the time-intensity Curve (AUC) as a function of various contrast-agent concentrations. The splitter provided four different concentrations simultaneously ranging from 12.5% to 100% of the initial concentration of the SonoVue contrast agent (Bracco Imaging S.p.A., Milan, Italy), therefore, measuring four AUCs in a single injection. The plot of the AUC as a function of the four contrast agent concentrations represents the intensity variation of the harmonic signal: the slope being the calibration parameter. The standardization through this method implied that both generations of ultrasound scanners had to have the same slopes to be considered as calibrated. This method was tested on two ultrasound scanners from the same manufacturer (Aplio500, Aplioi900, Canon Medical Systems, Tokyo, Japan). The Aplio500 used the settings defined by the initial multicenter DCE-US study. The Mechanical Index (MI) and the Color Gain (CG) of the Aplioi900 have been adjusted to match those of the Aplio500. The reliability of the new setup was evaluated in terms of measurement repeatability, and reproducibility with the agreement between the measurements obtained once the two ultrasound scanners were calibrated. The new setup provided excellent repeatability measurements with a value of 96.8%. Once the two ultrasound scanners have been calibrated for both types of probes, the reproducibility was excellent with the agreement between their respective quantitative measurement was at the lowest 95.4% and at the best 98.8%. The settings of the Aplioi900 (Canon Medical Systems) were adjusted to match those of the Aplio500 (Canon Medical Systems) and these validated settings were for the abdominal probe: MI=0.13 and CG=34dB; and for the linear probe: MI=0.10 and CG=38dB. This new calibration setup provided reliable measurements and enabled the rapid transfer and the use of the DCE-US imaging protocol on new ultrasound scanners, thus permitting a continuation of the therapeutic evaluation of patients through quantitative imaging.