scholarly journals Parameter Optimization for Selected Correlation Analysis of Intracranial Pathophysiology

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Rupert Faltermeier ◽  
Martin A. Proescholdt ◽  
Sylvia Bele ◽  
Alexander Brawanski
Keyword(s):  
Correlation Analysis ◽  
Cerebral Autoregulation ◽  
High Sensitivity ◽  
Mathematical Tool ◽  
Time Resolved ◽  
Arterial Blood ◽  
Severe Impairment ◽  
Windowing Technique ◽  
Tool Set ◽  
Real Time Application

Recently we proposed a mathematical tool set, called selected correlation analysis, that reliably detects positive and negative correlations between arterial blood pressure (ABP) and intracranial pressure (ICP). Such correlations are associated with severe impairment of the cerebral autoregulation and intracranial compliance, as predicted by a mathematical model. The time resolved selected correlation analysis is based on a windowing technique combined with Fourier-based coherence calculations and therefore depends on several parameters. For real time application of this method at an ICU it is inevitable to adjust this mathematical tool for high sensitivity and distinct reliability. In this study, we will introduce a method to optimize the parameters of the selected correlation analysis by correlating an index, called selected correlation positive (SCP), with the outcome of the patients represented by the Glasgow Outcome Scale (GOS). For that purpose, the data of twenty-five patients were used to calculate the SCP value for each patient and multitude of feasible parameter sets of the selected correlation analysis. It could be shown that an optimized set of parameters is able to improve the sensitivity of the method by a factor greater than four in comparison to our first analyses.

scholarly journals Detection of Impaired Cerebral Autoregulation Using Selected Correlation Analysis: A Validation Study

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Martin A. Proescholdt ◽  
Rupert Faltermeier ◽  
Sylvia Bele ◽  
Alexander Brawanski
Keyword(s):  
Correlation Analysis ◽  
Cerebral Autoregulation ◽  
Neurological Diseases ◽  
Simultaneous Detection ◽  
Monitoring Data ◽  
Reactivity Index ◽  
Analysis Tool ◽  
Mathematical Tool ◽  
Tool Set ◽  
Brain Monitoring

Multimodal brain monitoring has been utilized to optimize treatment of patients with critical neurological diseases. However, the amount of data requires an integrative tool set to unmask pathological events in a timely fashion. Recently we have introduced a mathematical model allowing the simulation of pathophysiological conditions such as reduced intracranial compliance and impaired autoregulation. Utilizing a mathematical tool set called selected correlation analysis (sca), correlation patterns, which indicate impaired autoregulation, can be detected in patient data sets (scp). In this study we compared the results of the sca with the pressure reactivity index (PRx), an established marker for impaired autoregulation. Mean PRx values were significantly higher in time segments identified as scp compared to segments showing no selected correlations (nsc). The sca based approach predicted cerebral autoregulation failure with a sensitivity of 78.8% and a specificity of 62.6%. Autoregulation failure, as detected by the results of both analysis methods, was significantly correlated with poor outcome. Sca of brain monitoring data detects impaired autoregulation with high sensitivity and sufficient specificity. Since the sca approach allows the simultaneous detection of both major pathological conditions, disturbed autoregulation and reduced compliance, it may become a useful analysis tool for brain multimodal monitoring data.

scholarly journals Windowed Multitaper Correlation Analysis of Multimodal Brain Monitoring Parameters

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Rupert Faltermeier ◽  
Martin A. Proescholdt ◽  
Sylvia Bele ◽  
Alexander Brawanski
Keyword(s):  
Cerebral Perfusion ◽  
Neurocritical Care ◽  
Daily Practice ◽  
Statistical Testing ◽  
Huge Amount ◽  
Time Resolved ◽  
Testing Method ◽  
Arterial Blood ◽  
Windowing Technique ◽  
Statistical Testing Method

Although multimodal monitoring sets the standard in daily practice of neurocritical care, problem-oriented analysis tools to interpret the huge amount of data are lacking. Recently a mathematical model was presented that simulates the cerebral perfusion and oxygen supply in case of a severe head trauma, predicting the appearance of distinct correlations between arterial blood pressure and intracranial pressure. In this study we present a set of mathematical tools that reliably detect the predicted correlations in data recorded at a neurocritical care unit. The time resolved correlations will be identified by a windowing technique combined with Fourier-based coherence calculations. The phasing of the data is detected by means of Hilbert phase difference within the above mentioned windows. A statistical testing method is introduced that allows tuning the parameters of the windowing method in such a way that a predefined accuracy is reached. With this method the data of fifteen patients were examined in which we found the predicted correlation in each patient. Additionally it could be shown that the occurrence of a distinct correlation parameter, called scp, represents a predictive value of high quality for the patients outcome.

scholarly journals A Patient-Independent Significance Test by Means of False-Positive Rates in Selected Correlation Analysis of Brain Multimodal Monitoring Data

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Rupert Faltermeier ◽  
Martin A. Proescholdt ◽  
Stefan Wolf ◽  
Sylvia Bele ◽  
Alexander Brawanski
Keyword(s):  
Correlation Analysis ◽  
Neurological Diseases ◽  
Significance Test ◽  
Error Rates ◽  
Time Resolved ◽  
Significance Level ◽  
Multimodal Monitoring ◽  
Arterial Blood ◽  
Significance Levels ◽  
The Individual

Recently, we introduced a mathematical toolkit called selected correlation analysis (sca) that reliably detects negative and positive correlations between arterial blood pressure (ABP) and intracranial pressure (ICP) data, recorded during multimodal monitoring, in a time-resolved way. As has been shown with the aid of a mathematical model of cerebral perfusion, such correlations reflect impaired autoregulation and reduced intracranial compliance in patients with critical neurological diseases. Sca calculates a Fourier transform-based index called selected correlation (sc) that reflects the strength of correlation between the input data and simultaneously an index called mean Hilbert phase difference (mhpd) that reflects the phasing between the data. To reliably detect pathophysiological conditions during multimodal monitoring, some thresholds for the abovementioned indexes sc and mhpd have to be established that assign predefined significance levels to that thresholds. In this paper, we will present a method that determines the rate of false positives for fixed pairs of thresholds (lsc, lmhpd). We calculate these error rates as a function of the predefined thresholds for each individual out of a patient cohort of 52 patients in a retrospective way. Based on the deviation of the individual error rates, we subsequently determine a globally valid upper limit of the error rate by calculating the predictive interval. From this predictive interval, we deduce a globally valid significance level for appropriate pairs of thresholds that allows the application of sca to every future patient in a prospective, bedside fashion.

scholarly journals Effects of Crystal Morphology on the Hot-Carrier Dynamics in Mixed-Cation Hybrid Lead Halide Perovskites

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 708
Author(s):  
Daniele Catone ◽  
Giuseppe Ammirati ◽  
Patrick O’Keeffe ◽  
Faustino Martelli ◽  
Lorenzo Di Mario ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Carrier Dynamics ◽  
Large Area ◽  
Photovoltaic Properties ◽  
Time Resolved ◽  
Hot Carrier ◽  
Mixed Cation ◽  
Small Crystals ◽  
Characterization Of Materials ◽  
Lead Halide

Ultrafast pump-probe spectroscopies have proved to be an important tool for the investigation of charge carriers dynamics in perovskite materials providing crucial information on the dynamics of the excited carriers, and fundamental in the development of new devices with tailored photovoltaic properties. Fast transient absorbance spectroscopy on mixed-cation hybrid lead halide perovskite samples was used to investigate how the dimensions and the morphology of the perovskite crystals embedded in the capping (large crystals) and mesoporous (small crystals) layers affect the hot-carrier dynamics in the first hundreds of femtoseconds as a function of the excitation energy. The comparative study between samples with perovskite deposited on substrates with and without the mesoporous layer has shown how the small crystals preserve the temperature of the carriers for a longer period after the excitation than the large crystals. This study showed how the high sensitivity of the time-resolved spectroscopies in discriminating the transient response due to the different morphology of the crystals embedded in the layers of the same sample can be applied in the general characterization of materials to be used in solar cell devices and large area modules, providing further and valuable information for the optimization and enhancement of stability and efficiency in the power conversion of new perovskite-based devices.

Urinary gonadotropin measurements by enhanced luminometric assays (LIA) for the evaluation of pubertal development

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
And Demir ◽  
Adem Aydın ◽  
Atilla Büyükgebiz ◽  
Ulf-Håkan Stenman ◽  
Matti Hero
Keyword(s):  
Healthy Subjects ◽  
Reliable Method ◽  
Pubertal Development ◽  
High Sensitivity ◽  
Tanner Stage ◽  
Time Resolved ◽  
Stage 1 ◽  
Sensitive Detection Technique ◽  
Serum And Urine

Abstract Objectives Determination of LH in urine has proved to be a reliable method for evaluation of pubertal development. The human LH assay based on time-resolved immunofluorometric (IFMA) technology (AutoDELFIA, PerkinElmer, Wallac) has been found to be suitable for this purpose thanks to its high sensitivity but other assays have not been evaluated. We have analyzed our data obtained by another potentially sensitive detection technique, enhanced luminometric assay (LIA) with the objective of finding a viable alternative to IFMA since these may not be available in the future. Methods LIA was used to measure LH and FSH in serum and urine samples from 100 healthy subjects of each Tanner stage and both genders, whose pubertal development has been determined. Results Urinary gonodotropin concentrations measured by LIA correlated well with Tanner stage [(r=0.93 for girls, r=0.81 for boys; p<0.01 for LH) and (r=0.81 for girls, r=0.73 for boys; p<0.01 for FSH)]. LIA determinations revealed the increase in U-LH concentrations during the transition from Tanner stage 1–2 in both girls and boys (p<0.001), whereas U-FSH and S-LH were able to detect the increase from Tanner stage 1–2 only in boys or girls, respectively (both p<0.001). Conclusions Measurement of urinary gonadotropin concentrations by LIA may be useful for the evaluation of overall pubertal development and also in the detection of transition from prepuberty to puberty.

Neutrophil gelatinase-associated lipocalin as a potential biomarker for pulmonary thromboembolism

2019 ◽  
Vol 45 (1) ◽  
pp. 51-56
Author(s):  
Songul Ozyurt ◽  
Mevlut Karatas ◽  
Medeni Arpa ◽  
Bilge Yilmaz Kara ◽  
Hakan Duman ◽  
...  
Keyword(s):  
Predictive Value ◽  
Pulmonary Thromboembolism ◽  
High Sensitivity ◽  
Control Group ◽  
Arterial Blood Gas ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Arterial Blood ◽  
Potential Biomarker ◽  
Healthy Control ◽  
Neutrophil Gelatinase

Abstract Objective Pulmonary thromboembolism (PTE) is a clinical condition that can be lethal unless promptly diagnosed and treated. The objective was to evaluate the significance of serum neutrophil gelatinase-associated lipocalin (NGAL) in the diagnosis of PTE. Materials and methods In this study, 60 patients hospitalized for acute PTE between May 2015 and December 2016 were enrolled. PTE was diagnosed using spiral computed tomography angiography of the thorax. Cardiac enzyme levels, arterial blood gas, and echocardiography measurements were performed. Whole blood samples were drawn to measure serum NGAL before treatment. Results The PTE group comprised 34 women and 26 men, and the healthy control group included 22 women and 18 men. The mean ages of the patient and control groups were 70.3 ± 14.4 years and 69.0 ± 10.2 years, respectively. Serum NGAL was significantly higher in the patients than in the controls (88.6 ± 33.6 vs. 31.7 ± 10.0 ng/mL, p < 0.001, respectively). The optimal NGAL cut-off value was >50 ng/mL, the sensitivity was 100%, specificity was 98.3%, the negative predictive value was 100%, and the positive predictive value was 68%. Conclusion Serum NGAL is a new biomarker with high sensitivity and specificity to detect, diagnose, and exclude PTE.

Sensor Fused Blood Pressure Measuring Device Capable of Recording Korotkoff Sounds in Inflationary Curves

2020 ◽  
Author(s):  
Enrique Alvarez Vazquez ◽  
Daniel Ewert ◽  
Dave Jorgenson ◽  
Michael Sand
Keyword(s):  
Blood Pressure ◽  
Cuff Pressure ◽  
High Sensitivity ◽  
Skin Surface ◽  
Pressure System ◽  
Measuring Device ◽  
Arterial Blood ◽  
Pressure Cuff ◽  
System 2 ◽  
Control Electronics

Abstract This study describes a non-invasive medical device capable of measuring arterial blood pressure (BP) with a combination of inflationary and deflationary procedures. The device uses the pressure cuff pressure signal, arterial skin-surface acoustics, and photoplethysmography (PPG) to make a sensor-fusion estimation of blood pressure readings. We developed an apparatus composed of 1) a modified off-the-shelf oscillometric blood pressure system, 2) a contact microphone with an amplifier, 3) and high-sensitivity pulse oximeter, and its control electronics.

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