Absolute Intensity Values Research Articles

Assessment of Foot Perfusion Before and After Revascularization of Critically Ischemic Foot Using Indocyanine Green Fluorescence Imaging

Introduction: Critical limb ischemia (CLI) is a clinical diagnosis, confirmed by objective tests, usually ABI, toe pressure (TP) and TcPO2. Indocyanine green fluorescence imaging (ICG-FI) is a diagnostic modality for assessing the perfusion of tissues. Although some application has been described of ICG-FI in the assessment of ischemic foot, the technique is uncommon in vascular surgery. Our aim was to study the usefulness of ICG-FI in the quality control of revascularization. Methods: One hundred and one patients with 104 CLI limbs were studied with ICG-FI using SPY Elite. ABI and TP were measured in all patients. After ICG-FI, assessment of circulation was done using time–intensity curve derived from two regions of interest. Three parameters were derived from the curves: Maximum ingress, meaning the absolute value of the maximum intensity; ingress rate, meaning the value from the time intensity curve describing the increase in maximum ingress per seconds and SPY10, which is the intensity achieved during the first 10 seconds after the foot starts to gain intensity. Results: Ninety-five technically successful procedures was achieved, 63 (66.3%) endovascular and 32 (33.7%) surgical revascularizations. In 9 (9.5%) patients, an open line from the aorta to the foot was not achieved due to a failure to recanalize the occlusion (n = 7) or due to distal embolization (n = 2). The mean ingress values before and after the procedure in patients who underwent successful revascularization were 81 ± 47 units and 120 ± 5 units of ingress (p < .001) and ingress rates 4.2 ± 4 units/second and 8.0 ± 6.2 units/second (p = .001), respectively. In the PTA patients in whom the revascularization was unsuccessful, no changes were seen in the hemodynamic parameters. In 6 (8.8%) patients who underwent technically successful revascularization, the SPY values were worse after the revascularization than at the baseline. In all cases an explanation was found in closer evaluation. Conclusion: ICG-FI with SPY Elite provides reliable information on the success of revascularization, in addition to implicating possible failure if there is no improvement in the ICG-FI variables. It gives valuable information to complement traditional assessment methods. Disclosure of Interest: None Declared.

Study on the Regulation of Cell Morphology by Matrix Nanotopography in 3D Environment

Matrix nanotopography plays an important role in regulating cell morphology by providing spatial as well as mechanical cues for cells to sense, and cortical actin and focal adhesions are important to maintain cell morphology and resist deformation. Most studies were based on 2D substrate, it still remains unclear about the influence of nanotopography on cell morphology in 3D environment.We proposed an effective method to fabricate hollow spherical PDMS scaffold whose topography could be determined by different etching of mold, the polystyrene microspheres. After culturing REF cells in two kinds of scaffold, one with smooth surface and the other one with numerous nano spikes, we found cells tend to attached more of its body to the smooth scaffold with more focal adhesions, while the cells in the etched scaffold with multiple nano spikes prefer to attach to less anchoring sites with reduced number of focal adhesions. Negative correlation was found between the absolute value of curvature and cortical actin intensity and high intensity actin were mostly concentrated in region Gaussian curvature close to 0, also highly-aligned stress fibers tend to be formed at such tube-like structure. Moreover, the major actin intensity and mean/Gaussian curvature distribution for cells in etched scaffold are concentrated in a smaller range with lower value, compared to the relative scattering major distribution for cells in unetched scaffold, meanwhile different parts of cell surface also exhibited specific range of surface curvature and actin intensity. Together, it suggests that 3D matrix topography would affect cell morphology as well as focal adhesions distribution, also there is close interplay between cell morphology and FAs, which together contribute to the regulation of actin distribution, and actin distribution would in turn influence cell morphology.

Effect of cutting parameters on machinability characteristics in milling of magnesium alloy with carbide tool

Magnesium alloy has attracted more attentions due to its excellent mechanical properties. However, in process of dry cutting operation, many problems restrict its further development. In this article, the effect of cutting parameters on machinabilities of magnesium alloy is explored under dry milling condition. This research is an attempt to investigate the impact of cutting speed at multiple feed rates on cutting force and surface roughness, while a statistical analysis is adopted to determine the influential intensities accurately. The results showed that cutting force is affected by the positively constant intensity from feed rate and the increasingly negative intensity from cutting speed. In contrast, surface roughness is determined by the gradually increasing negative tendency from feed rate and the positive effect with constant intensity from cutting speed. Within the range of the experiments, feed rate is the leading contribution for cutting force while the cutting speed is the dominant factor for surface roughness according to the absolute intensity values. Meanwhile, the trends of influencing intensities between cutting force and surface roughness are opposite. Besides, it is also found that in milling magnesium alloy, chip morphology is highly sensitive to cutting speed while the chip quality mainly depends on feed rate.

Optimization of Region of Interest Drawing for Quantitative Analysis: Differentiation Between Benign and Malignant Breast Lesions on Contrast-Enhanced Sonography.

This study was performed to evaluate the diagnostic utility of quantitative analysis of benign and malignant breast lesions using contrast-enhanced sonography. Contrast-enhanced sonography using the perflubutane-based contrast agent Sonazoid (Daiichi Sankyo, Tokyo, Japan) was performed in 94 pathologically proven palpable breast mass lesions, which could be depicted with B-mode sonography. Quantitative analyses using the time-intensity curve on contrast-enhanced sonography were performed in 5 region of interest (ROI) types (manually traced ROI and circular ROIs of 5, 10, 15, and 20 mm in diameter). The peak signal intensity, initial slope, time to peak, positive enhancement integral, and wash-out ratio were investigated in each ROI. There were significant differences between benign and malignant lesions in the time to peak (P < .05), initial slope (P < .001), and positive enhancement integral (P < .05) for the manual ROI. Significant differences were found between benign and malignant lesions in the time to peak (P < .05) for the 5-mm ROI; the time to peak (P < .05) and initial slope (P< .05) for the 10-mm ROI; absolute values of the peak signal intensity (P< .05), time to peak (P< .01), and initial slope (P< .005) for the 15-mm ROI; and the time to peak (P < .05) and initial slope (P < .05) for the 20-mm ROI. There were no statistically significant differences in any wash-out ratio values for the 5 ROI types. Kinetic analysis using contrast-enhanced sonography is useful for differentiation between benign and malignant breast lesions.

Analysis of sexual assault evidence: statistical classification of condoms by ambient mass spectrometry.

Desorption electrospray ionization mass spectrometry (DESI-MS) and easy ambient sonic-spray ionization mass spectrometry (EASI-MS) are employed here in the forensic analysis of chemical compounds found in condoms and relative traces, and their analytical performances are compared. Statistical analysis of data obtained from mass spectra only was applied in order to obtain classification rules for distinguishing ten types of condoms. In particular, two supervised chemometric techniques [linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA)] were carried out on absolute and relative intensity values to test the performances of statistical models in terms of predictive capacity. The achieved classification of samples was excellent because of the high prediction percentages of the method used both for DESI and EASI mass spectrometry analyses, confirming these two as potential ambient ionization techniques for forensic analyses in case of sexual assault crimes. EASI-MS showed 99% prediction ability for LDA using relative data and 100% prediction ability for SIMCA using both absolute and relative ones, while DESI showed 94% prediction ability for both LDA and SIMCA. The absence of any sample preparation technique gives advantages in terms of sample preservation and reduced contamination, allowing successive analyses to be performed on the same sample by other techniques.

Spectral-tomographic methods and means of studying propellant flows of ion and plasma low-thrust engines

Methods of spectral-tomographic diagnostics of ion and plasma jets in ion-plasma low-thrust engines are described. Methods that I have developed of 2D and 3D reconstruction of local values of temperature, concentration and absolute intensity in the ion-plasma jet are analyzed. Experimental setups of laboratory type for studying parameters of propellants of ion and plasma propulsion engines are described.

COMPARATIVE LEARNING APPLIED TO INTENSITY RATING OF FACIAL EXPRESSIONS OF PAIN

Together with classification of facial expressions, the rating of their intensities is of major interest. Classical supervised learning techniques require labeling of the intensities, which is labor intensive and requires expert knowledge, but nevertheless is not guaranteed to be objective. We propose a new approach to learn an intensity rating function which does not require expert knowledge, because it simplifies the labeling task by avoiding the difficulty of selecting an absolute intensity value and to keep the labeling consistent for the whole dataset. It is based on a novel kind of ground truth which we call Comparative Labeling. It specifies sample pairs for which the first element is desired to have a lower intensity than the second. We introduce a learning scheme to find an optimal intensity function in respect of the Comparative Labeling and propose performance measures to assess the quality of the learned function. The technique is applied to rate the intensity of facial expressions of posed pain. The evaluation results show that the learned function is well suited for determining dynamic intensity variation over time. We also assess the suitability of the rating as an inter-individual intensity measure by comparing it to the intensity ratings given by human observers.

Joint set intensity estimation: comparison between investigation modes

Recent mathematical calculations allow us to define set fracture intensity (I), i.e., the amount of rock mass affected by fracture sets, independently of the investigation mode. This parameter, characteristic of each rock mass, is of much interest to describe the mechanical response of the rock mass to external influences. The aim of this work is to apply these mathematical equations on one site using measurements of three distinct fracture sets: (1) on a plane surface, (2) along a scanline, and (3) using borehole imaging, in order to evaluate and explain variability in collected data. Even if the three types of measurements give differences on absolute intensity values, they still define similar trends, i.e., the order of the fracturing impact of joint sets is the same from the three measurement methods, irrespective of the fact that obtained values are quite different from one survey method to another. We discuss the possible origins of these biases.

Determination of the gamma emission intensities of 111Ag

A radioactive solution of 111Ag, standardised by the absolute measurement methods 4π(PC)-γ and 4π(LS)-γ coincidence counting at the National Physical Laboratory (NPL), was measured by two independently calibrated HPGe γ spectrometers in order to estimate the γ emission intensities and to determine the absolute intensity, with the aim of improving the currently published values. An absolute intensity value of 6.68 (7)% was obtained for the 342.1keV γ emission, which is in agreement with previously reported values, but greatly reduces the uncertainty. Additionally, this work proposes a new emission intensity for the 450.0keV γ emission that has not been previously reported, with an absolute intensity of 0.000482 (12)%. An investigation of the published γ emission intensities shows significant discrepancies that require resolution.

Feasibility of using infra-red system for absolute calibration of high intensity focused ultrasound fields

In recent years, considerable progress has been achieved in the use of infrared (IR) method for measuring acoustic fields of high intensity focused ultrasound (HIFU) transducers. The principle of the method is to determine the intensity distribution at the surface of an acoustic absorber by measuring the distribution of the initial rate of temperature increase at the start of insonation. Here, the method is extended to estimate the absolute values of intensity in ultrasound fields of HIFU transducers. The approach compares the temperature rise measured at the surface of a thin absorber using an IR camera and the pressure distribution measured in water using a hydrophone. The measurements were carried out for two focused HIFU transducers and a flat physiotherapy transducer. During the IR measurement, the transducer was driven in tone burst mode to avoid interference from reflected acoustic waves between the absorber/air interface and the transducer. The method enables fast quantitative estimations of intensity distributions that agree well with hydrophone measurements and gives reasonably consistent results for medical transducers of different geometries. [Work was supported in parts by RFBR 12-02-31388, 12-02-00028, 13-02-00183; NIH 2R01EB007643-05, the European Metrology Research Programme (Joint Research Project HLT03) and the UK National Measurement Office.]

Quantitative FLAIR analysis indicates predominant affection of the amygdala in antibody‐associated limbic encephalitis

Limbic encephalitis is an autoimmune-mediated disease leading to temporal lobe epilepsy, mnestic deficits, and affective disturbances. Magnetic resonance imaging (MRI) usually shows signal and volume changes of the temporomesial structures. However, these abnormalities may be subtle, thereby hampering the diagnosis by conventional visual assessment. In the present study we evaluated the diagnostic value of a fully automated MRI postprocessing technique in limbic encephalitis and hippocampal sclerosis. The MRI postprocessing was based largely on a recently described method allowing for an observer-independent quantification of the fluid-attenuated inversion recovery (FLAIR) signal intensities of amygdala and hippocampus. A 95% confidence region was calculated from the FLAIR intensities of 100 healthy controls. We applied this analysis to the MRI data of 39 patients with antibody-associated limbic encephalitis and 63 patients with hippocampal sclerosis. Moreover, the results were compared to those of visual assessment by an experienced neuroradiologist. The method detected limbic encephalitis and hippocampal sclerosis with a high sensitivity of 85% and 95%, respectively. The detection rate of the automated approach in limbic encephalitis was significantly superior to visual analysis (85% vs. 51%; p = 0.001), whereas no statistically significant difference for the detection rate in hippocampal sclerosis was found. Patients with limbic encephalitis had significantly higher absolute intensity values of the amygdala and a significantly higher percentage fell outside of the amygdalar confidence region compared to those with hippocampal sclerosis (79% vs. 27%; p < 0.001), whereas we found opposite results in the hippocampal analysis (38% vs. 95%; p < 0.001). The FLAIR analysis applied in this study is a powerful tool to quantify signal changes of the amygdala and hippocampus in limbic encephalitis and hippocampal sclerosis. It significantly increases the diagnostic sensitivity in limbic encephalitis in comparison to conventional visual analysis. Furthermore, the method provides an interesting insight into the distinct properties of these two disease entities on MRI, indicating a predominant affection of the amygdala in limbic encephalitis, whereas the affection of the hippocampus is far less pronounced when compared to hippocampal sclerosis.

Damages indicators for post-earthquake condition assessment

After an earthquake, the condition of industrial systems, structures and equipment, especially at nuclear power plants has to be assessed since this information is needed for accident management and for the decision on the continuation of the operation. The damaging potential of the earthquake can be characterized by maximum horizontal acceleration of the ground motion, response spectra, cumulative absolute velocity and different instrumental intensity values. These quantities can be correlated with the earthquake characteristics, magnitude, distance, etc. Some of the indices are selective to damage mechanism and can be correlated to load-bearing features of the structures. Different indicators of damaging potential of earthquakes are analyzed in the paper from the point of view of applicability for post-event condition assessment at nuclear power plants and for using as criteria for restart of the operation.

SPY-Q Analysis Toolkit Values Potentially Predict Mastectomy Flap Necrosis

Previously, we and other investigators have reported the benefits of using SPY Intraoperative Perfusion Assessment System to assist in the prediction of mastectomy flap necrosis. To date, analysis of the SPY images has been subjective. However, the new SPY-Q postprocessing software allows for objective quantification of SPY images through the application of absolute and relative values of fluorescence intensity. This study seeks to determine the use of these objective, numerical data and their role in potentially predicting mastectomy flap necrosis. In a retrospective fashion, 20 SPY images from immediate breast reconstructions were randomly selected from a database of more than 100 images: 10 from breasts that developed flap necrosis and 10 from breasts that demonstrated adequate healing. Groups were matched for age, body mass index, and comorbidities. The points of necrosis and points of adequate healing were evaluated using the postprocessing software, and the groups were compared. The mean "relative" fluorescence of the necrosis and the adequate healing groups was 25.2% and 43.3%, respectively (P < 0.001). The mean absolute fluorescence of the 2 groups was 18.5 and 25.0, respectively (P = 0.07). These findings suggest that quantitative "relative" perfusion values as generated by the postprocessing software may augment clinical judgment of flap viability in an objective and reproducible fashion.

Differentiation of an Intrapancreatic Accessory Spleen from a Small (&lt;3-cm) Solid Pancreatic Tumor: Value of Diffusion-weighted MR Imaging

To evaluate the value of diffusion-weighted (DW) imaging in differentiation of an intrapancreatic accessory spleen (IPAS) from a small (<3 cm) solid pancreatic tumor. This retrospective study was approved by the institutional review board, and informed consent was waived. Twenty patients with IPAS and 22 patients with small solid pancreatic tumors were included. All patients underwent abdominal magnetic resonance (MR) imaging with DW and gadoxetic acid-enhanced imaging. Qualitative (signal intensity) and quantitative (signal intensity and apparent diffusion coefficient [ADC]) evaluations were performed by two observers. Fisher exact test and Mann-Whitney U test were used for comparing groups. Compared with the spleen, the IPAS showed isointensity more frequently than did small pancreatic tumors on T2-weighted images (95% [19 of 20] vs 41% [nine of 22]), arterial phase images (100% [20 of 20] vs 18% [four of 22]), portal phase images (100% [20 of 20] vs 23% [five of 22]), late phase images (100% [20 of 20] vs 41% [nine of 22]), and DW images with b value of 0 sec/mm(2) (100% [20 of 20] vs 9% [two of 22]), b value of 100 sec/mm(2) (95% [19 of 20] vs 27% [six of 22]), and b value of 800 sec/mm(2) (100% [20 of 20] vs 27% [six of 22]), with significant differences (P < .01). The means of the absolute value of relative signal intensity and ADC ratio on DW images of IPAS were significantly lower and closer to zero than those of pancreatic tumors (P < .05). Visual assessment of the similarity between pancreatic lesion and spleen on DW images for diagnosis of IPAS yielded diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 95% (40 of 42), 100% (20 of 20), 91% (20 of 22), 91% (20 of 22), and 100% (20 of 20), respectively, for observer 1 and 90% (38 of 42), 95% (19 of 20), 86% (19 of 22), 86% (19 of 22), and 95% (19of 20), respectively, for observer 2. In addition to conventional morphologic MR imaging, DW imaging can be used as a tool for differentiating IPAS from solid pancreatic tumors. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112765/-/DC1.

Differentiation between benign and malignant breast tumors using kinetic features of real-time harmonic contrast-enhanced ultrasound

Contrast-enhanced ultrasound (CEUS) has gained interest because of its ability to gather vascular information in diverse organs. There is still a subject of debate concerning its value in breast lesions, especially as a differential diagnostic tool. To investigate whether kinetic parameters of CEUS can differentiate between malignant and benign breast lesions. We evaluated 75 malignant and 21 benign lesions in the breast or axilla. Contrast harmonic imaging (CHI) US was performed after the injection of a bolus dose of 2.4 mL of Sono Vue® (Bracco, Milano, Italy). The following parameters were calculated for kinetic analysis: initial slope, time to peak enhancement, wash-out ratios W(21) and W(50) (relative decrease in signal intensity from the peak enhancement to 21 s and 50 s, respectively). A significant difference was found between the benign and malignant lesions in time-to-peak (P value <0.05) and wash-out ratios W(21) (P value <0.001) and W(50) (P value <0.001). The mean time-to-peak was 9.3 s for malignant and 14.6 s for benign lesions. The mean signal drop from peak to signal intensity measured at 50 s was 85% for malignant and 66% for benign lesions. There was no difference in absolute values of peak signal intensity and initial slope. The most significant difference between standardized benign and malignant wash-out curves was found at 21 s but statistical significance was reached in the range of 14-50 s. Real-time CEUS can evolve into a new non-invasive option for differentiate malignant from benign breast lesions.

On the accuracy of ab initio calculations of absolute band intensities in the IR spectra of molecules

Absolute intensities are calculated in the harmonic approximation for the IR spectrum of 18 hydrocarbons, oxygen- and nitrogen-containing organic compounds. The quantum chemical calculation is carried out in the 6-311G(3df,3pd) basis set. The calculated data are compared to the experimental values of absolute absorption intensities. It is found that calculations in the HF approximation substantially overestimate (on average by 87%) the integral absolute intensity of fundamental vibrations in the 575–4000 cm−1 range. Most part of this overestimation falls on the stretching vibrations with large amplitudes (C-H and C=O bonds). When the MP2 method is used without electron correlation treatment, this overestimation decreases to 22% and becomes more uniform in the whole spectral region.

Infrared spectroscopy of CO2 isotopologues from 2200 to 7000 cm−1: I—Characterizing experimental uncertainties of positions and intensities

Fourier transform spectra of carbon dioxide enriched in 17O and 18O have been recorded in LADIR (Paris, France) with the Bruker IFS 125-HR between 2000 and 9000cm−1 at an unapodized resolution of 0.0056cm−1. In this contribution we present a total of 1861 line positions and intensities retrieved for 46 bands of 12CO2 isotopologues between 2000 and 7000cm−1 including the 16O12C16O, 17O12C17O, 18O12C18O, 16O12C18O, 16O12C17O, and 17O12C18O species. The objective of this first part of work was to examine the absolute concentrations of various CO2 isotopologues in the sample by comparing our measurements of the line intensities to those available in literature and in HITRAN 2008. The accuracy of the determined abundances of the various isotopologues in our sample could be estimated to be about 2–7% for all above listed isotopologues except for 17O12C17O for which the accuracy on abundance is estimated to be around 20%. The accuracy of the line positions retrieval is better than 0.1×10−3cm−1. We estimate the relative uncertainty of the line intensities retrieval to be around 1–2% (except for very weak lines), whereas the absolute accuracy to be around 3–15% depending mainly on the accuracy of the determination of the partial pressures for the various isotopologues in our sample, but also on the line strengths and on the spectral region. The estimation of the partial pressures of the various CO2 isotopologues is crucial for retrieving absolute values of line intensities, but this is not an easy task because there are no absolute calibration standards for CO2 intensities. Among the results obtained in this work, measurements are obtained for the first time for the 10011–00001 band of 17O12C17O, 16O12C17O, 16O12C18O, and 18O12C18O species, for the 00011–00001 band of 17O12C18O, and for the 2001i–00001 (i=1, 2, and 3) bands of the 16O12C17O isotopologue.

High sensitivity ICLAS of H 218O between 13 540 and 14 100 cm −1

The high resolution absorption spectrum of 18O enriched water was recorded between 13 540 and 14 100 cm −1 by high sensitivity Intracavity Laser Absorption Spectroscopy (ICLAS). This spectral region corresponds to the relatively strong 4ν polyad. Four isotopologues of water (H 2 18O, H 2 16O, H 2 17O, HD 18O) are found to contribute to the spectrum. About 1800 H 2 18O lines were assigned by comparison with variational calculations. Altogether, 855 accurate energy levels of H 2 18O were determined from transitions attributed to 23 upper vibrational states, 342 of them being reported for the first time. New information includes 84 energy levels of H 2 17O present with a 1.5% relative concentration in the sample and the rotational structure of the 4ν 3 band of HD 18O at 13814.520 cm −1. By comparison with variational calculations and with ICLAS absolute intensity values, a systematic overestimation by about 25% has been evidenced for the H 2 18O intensity values included in the HITRAN database for the 12 400–14 520 cm −1 range.

Calibration of HIFU intensity fields measured using an infra-red camera

A trend in HIFU technologies is to use 2D phased arrays that offer electronic steering of a single focus and formation of patterns of multiple foci. Conventional methods to characterize array fields using scanned hydrophone would be prohibitively slow given the potentially large number of focusing conditions. An alternative technique for rapid qualitative assessment of intensity distributions was recently developed. The method is based on infrared camera measurements of the temperature rises induced by low amplitude short ultrasonic bursts in a thin absorber. Here, the method is extended to estimate the absolute values of intensity in a field of a 2D 1-MHz randomized phased array. Two approaches were implemented. In the first approach it was assumed that the measured temperature rise at the surface of the absorber is proportional to the free field intensity. The second approach correlated the temperature rise measured in an absorber and calculated from the modelled acoustic field and the heat transfer equation. Corresponding correction factors between the free field intensity and temperature was obtained and introduced in the conversion of temperature images to intensity. Free field distributions in water and focusing through ribs were recorded and simulated. Good correlation between the measured and modeled results in both spatial distributions and the absolute values of intensity was demonstrated.

Comparison of performance of one-color and two-color gene-expression analyses in predicting clinical endpoints of neuroblastoma patients

Microarray-based prediction of clinical endpoints may be performed using either a one-color approach reflecting mRNA abundance in absolute intensity values or a two-color approach yielding ratios of fluorescent intensities. In this study, as part of the MAQC-II project, we systematically compared the classification performance resulting from one- and two-color gene-expression profiles of 478 neuroblastoma samples. In total, 196 classification models were applied to these measurements to predict four clinical endpoints, and classification performances were compared in terms of accuracy, area under the curve, Matthews correlation coefficient and root mean-squared error. Whereas prediction performance varied with distinct clinical endpoints and classification models, equivalent performance metrics were observed for one- and two-color measurements in both internal and external validation. Furthermore, overlap of selected signature genes correlated inversely with endpoint prediction difficulty. In summary, our data strongly substantiate that the choice of platform is not a primary factor for successful gene expression based-prediction of clinical endpoints.