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Biomedical signal and Image processing

IEEE PULSE 2011年第3期2卷 41-54页

作者： Cerutti, Sergio Baselli, Giuseppe Bianchi, Anna Maria Caiani, Enrico Contini, Davide Cubeddu, Rinaldo Dercole, Fabio Di Rienzo, Luca Liberati, Diego Mainardi, Luca Ravazzani, Paolo Rinaldi, Sergio Signorini, Maria Gabriella Torricelli, Alessandro Politecn Milan Dipartimento Bioingn I-20133 Milan Italy Politecn Milan Dipartimento Fis I-20133 Milan Italy Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy Politecn Milan Dipartimento Elettrotecn I-20133 Milan Italy CNR Ist Elettron & Ingn Informaz & Telecomunicaz I-20133 Milan Italy Ist Nazl Fis Nucl I-20133 Milan Italy CNR Ist Ingn Biomed I-20133 Milan Italy

Generally, physiological modeling and biomedical signal processing constitute two important paradigms of biomedical engineering (BME): their fundamental concepts are taught starting from undergraduate studies and are more completely dealt with in the last years of graduate curricula, as well as in Ph.D. courses. Traditionally, these two cultural aspects were separated, with the first one more oriented to physiological issues and how to model them and the second one more dedicated to the development of processing tools or algorithms to enhance useful information from clinical data. A practical consequence was that those who did models did not do signal processing and vice versa. However, in recent years,the need for closer integration between signal processing and modeling of the relevant biological systems emerged very clearly [1], [2]. This is not only true for training purposes(i.e., to properly prepare the new professional members of BME) but also for the development of newly conceived research projects in which the integration between biomedical signal and image processing (BSIP) and modeling plays a crucial role. Just to give simple examples, topics such as brain–computer machine or interfaces,neuroengineering, nonlinear dynamical analysis of the cardiovascular (CV) system,integration of sensory-motor characteristics aimed at the building of advanced prostheses and rehabilitation tools, and wearable devices for vital sign monitoring and others do require an intelligent fusion of modeling and signal processing competences that are certainly peculiar of our discipline of BME.

关键词： Algorithms Biomedical Engineering Diagnostic Imaging Electrodiagnosis Humans Image Interpretation, computer-assisted Image processing, computer-assisted Models, Biological signal processing, computer-assisted

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Masimo signal extraction pulse oximetry

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JOURNAL OF CLINICAL MONITORING AND COMPUTING 2000年第7期16卷 475-483页

作者： Goldman, JM Petterson, MT Kopotic, RJ Barker, SJ Masimo Corp Irvine CA 92614 USA Univ Arizona Sch Med Dept Anesthesiol Tucson AZ 85724 USA

Objective. To describe a new pulse oximetry technology and measurement paradigm developed by Masimo Corporation. Introduction. Patient motion, poor tissue perfusion, excessive ambient light, and electrosurgical unit interference reduce conventional pulse oximeter (CPO) measurement integrity. Patient motion frequently generates erroneous pulse oximetry values for saturation and pulse rate. Motion-induced measurement error is due in part to widespread implementation of a theoretical pulse oximetry model which assumes that arterial blood is the only light-absorbing pulsatile component in the optical path. Methods. Masimo signal Extraction Technology (SET (R)) pulse oximetry begins with conventional red and infrared photoplethysmographic signals, and then employs a constellation of advanced techniques including radiofrequency and light-shielded optical sensors, digital signal processing, and adaptive filtration, to measure SpO(2) accurately during challenging clinical conditions. In contrast to CPO which calculates O-2 saturation from the ratio of transmitted pulsatile red and infrared light, Masimo SET pulse oximetry uses a new conceptual model of light absorption for pulse oximetry and employs the discrete saturation transform (DST) to isolate individual "saturation components" in the optical pathway. Typically, when the tissue under analysis is stationary, only the single saturation component produced by pulsatile arterial blood is present. In contrast, during patient motion, movement of non-arterial components (for example, venous blood) can be identified as additional saturation components (with a lower O-2 saturation). When conditions of the Masimo model are met, the saturation component corresponding to the highest O-2 saturation is reported by the instrument as SpO(2). Conclusion. The technological strategies implemented in Masimo SET pulse oximetry effectively permit continuous monitoring of SpO(2) during challenging clinical conditions of motion and poor tissu

关键词： pulse oximetry motion artifact oximetry/instrumentation/methods signal processing, computer-assisted adaptive filters Masimo signal extraction pulse oximetry signal extraction technology (SET (R))

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Enhanced fluorescence cyanide detection at physiologically lethal levels: Reduced ICT-based signal transduction

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2005年第10期127卷 3635-3641页

作者： Badugu, R Lakowicz, JR Geddes, CD Univ Maryland Sch Med Ctr Fluorescence Spect Dept Biochem & Mol BiolMed Biotechnol Ctr 725 W Lombard St Baltimore MD 21201 USA Univ Maryland Inst Biotechnol Inst Fluorescence Lab Adv Fluorescence SpectMed Biotechnol Ctr Baltimore MD 21201 USA

Three water-soluble fluorescent probes have been specifically designed to determine free cyanide concentrations up to physiologically lethal levels, > 20 mu M. The probes have been designed in such a way as to afford many notable sensing features, which render them unique with regard to signal transduction, photophysical characteristics, and their application to physiological cyanide determination and safeguard. The probes are readily able to reversibly bind free aqueous cyanide with dissociation constants around 4 mu M-3. Subsequent cyanide binding modulates the intramolecular charge transfer within the probes, a change in the electronic properties within the probes, resulting in enhanced fluorescence optical signals as a function of increased solution cyanide concentration. The ground-state chelation with cyanide produces wavelength shifts, which also enable the probes to sense cyanide in both an excitation and emission ratiometric manner, in addition to enhanced fluorescence signaling. This has enabled a generic cyanide sensing platform to be realized that is not dependent on fluorescent probe concentration, probe photodegradation, or fluctuations in the intensity of any employed excitation sources, ideal for remote cyanide sensing applications. Further, the > 600 nm fluorescence emission of the probes potentially allows for enhanced fluorescence ratiometric cyanide sensing in the optical window of tissues and blood, facilitating their use for the transdermal monitoring of cyanide for mammalian safeguard or postmortem in fire victims, both areas of active research.

关键词： Cyanides/analysis Cyanides/chemistry Fluorescent Dyes/chemistry Ruthenium/chemistry signal processing, computer-assisted Spectrometry, Fluorescence/methods

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Correcting for signal saturation errors in the analysis of microarray data

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BIOTECHNIQUES 2002年第2期32卷 330-+页

作者： Hsiao, LL Jensen, RV Yoshida, T Clark, KE Blumenstock, JE Gullans, SR Harvard Univ Sch Med Brigham & Womens Hosp Boston MA USA Wesleyan Univ Middletown CT USA

A variety of technical errors have arisen in data analysis when using cDNA or oligonucleotide microarrays. One of the most insidious problems is the saturation of the hybridization signal of high-abundant transcripts. This problem arises from the truncation of the laser fluorescence signal. When the hybridization signal on the microarray is very strong, this truncation can result in serious consequences that may not be readily apparent to the user As an illustration of this problem, two subclasses of normal human tissue samples (six liver and six lung samples) were analyzed with GeneChip(R) probe arrays to evaluate the patterns of expression for approximately 7000 human genes. Five of these data sets were found to suffer from signal truncation. This caused several tissues to be incorrectly classified using hierarchical clustering. To rectify this problem so that the gene expression data could be properly compared and clustered, we developed a "filtering" procedure that identifies a subset of genes least affected by the signal saturation. This filtering procedure can be obtained at ***.

关键词： Aged Algorithms DNA, Complementary Female Gene Expression Profiling Humans Liver/metabolism Lung/metabolism Male Nucleic Acid Hybridization Oligonucleotide Array Sequence Analysis/standards Quality Control RNA, Messenger/metabolism signal processing, computer-assisted

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Multidimensional Processes In Italy, biomedical signal and image processing embraces a multiparametric, multimodal, multiscale paradigm

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IEEE PULSE 2015年第4期6卷 44-49页

作者： Bianchi, Anna M. Baselli, Giuseppe Babiloni, Fabio Rizzo, Giovanna Politecn Milan Dept Elect Informat & Bioengn Biomed Engn Milan Italy Univ Roma La Sapienza Fac Med Physiol Rome Italy CNR Inst Mol Imaging & Physiol Milan Italy

Biomedical studies, both in research and in clinical applications, deal with the management of large amounts of data. Different sensors and transducers, advances in technologies, and the availability of innovative medical equipment and instrumentation all contribute to the ability to make biological measurements at different scales, ranging from systems, to organs, to tissues, to cells, right down to proteins and genes. Biomedical signals and data carry important information about the system or the organ that generated them.

关键词： Biomedical Engineering Biomedical Research Brain/physiology Brain-computer Interfaces Electroencephalography Humans Image processing, computer-assisted Italy Models, Neurological signal processing, computer-assisted Stroke/rehabilitation

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Sequence-specific detection of microRNAs by signal-amplifying ribozymes

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2004年第3期126卷 722-723页

作者： Hartig, JS Grüne, I Najafi-Shoushtari, SH Famulok, M Univ Bonn Kekule Inst Organ Chem & Biochem D-53121 Bonn Germany

The sequence-specific and sensitive detection of nucleic acids is becomingincreasingly important in applications ranging from basic research to diagnostics and *** indirect detection based on the polymerase chain reaction (PCR), transcription-mediatedamplification (TMA), or rolling circle amplification is sufficient for many of these purposes, onlyfew methods, most commonly in situ hybridization with radiolabeled or fluorescent probes, areavailable for the direct detection of a nucleic acid sequence in cells, tissues, or entireorganisms. The detection and quantification of small amounts of nucleic acids under these conditionsoften remains challenging. For example, it would be extremely useful to be able to directly detectand quantify small functional RNA sequences such as microRNAs (miRNAs) or riboswitches, thatregulate gene expression,1 as this might enable a direct profiling of their expression loci inside acell, tissue, or organism.

关键词： Animals Catalysis Drosophila melanogaster/genetics Fluorescence Resonance Energy Transfer/methods MicroRNAs/analysis MicroRNAs/analysis MicroRNAs/chemistry MicroRNAs/chemistry MicroRNAs/metabolism MicroRNAs/metabolism Nucleic Acid Conformation RNA, Catalytic/chemistry RNA, Catalytic/metabolism Sensitivity and Specificity signal processing, computer-assisted

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Looking for neuronal currents using MRI: An EEG-fMRI investigation of fast MR signal changes time-locked to frequent focal epileptic discharges

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NEUROIMAGE 2010年第3期50卷 1109-1117页

作者： Rodionov, Roman Siniatchkin, Michael Michel, Christoph M. Liston, Adam D. Thornton, Rachel Guye, Maxime Carmichael, David W. Lemieux, Louis UCL Dept Clin & Expt Epilepsy Inst Neurol London England Natl Soc Epilepsy MRI Unit Gerrards Cross Bucks England Univ Kiel Univ Hosp Pediat Neurol Kiel Germany Univ Geneva CH-1211 Geneva 4 Switzerland CNRS CRMBM UMR 6612 Marseille France

Rationale: Reproducible direct measurement of neuronal electrical activity using MRI signal changes due to local magnetic field perturbations would represent a step change in neuroimaging methods. While some previous studies using experiments based on evoked and spontaneous activity provided encouraging results no clear demonstration of neuronal current-related MR changes in the human brain has emerged to date. The availability of simultaneously acquired EEG-fMRI in patients with frequent interictal epileptic discharges (IED), which have significantly greater amplitude than evoked potentials, offers the opportunity to further investigate the phenomenon. Methods: We re-analysed simultaneously acquired EEG-fMRI data in 6 epilepsy patients with very frequent focal IED and a well-localised generator. A model of MRI signal changes due to fast activity and BOLD signal changes was used to identify fast MR signal changes. potentially directly reflecting neuronal activity. Simultaneously-acquired EEG allowed the comparison of electrical source localisation (ESI), clinical epilepsy localisation and BOLD signal changes with the fast MR signal changes. Results: Clusters of IED-related fast MR signal change were observed in all cases. Spatial correspondence between the IED-related fast MR, BOLD, ESI clusters and irritative zone (IZ) was observed in one slice of a single dataset. The other IED-related fast MR clusters were remote from electro-clinically determined generators of interictal activity. The sign and magnitude of the fast MR signal changes varied across regions and subjects. Conclusion: The observed fast MR changes cannot be confidently attributed to the direct effect of neuronal currents due to lack of spatial concordance with generators of interictal activity, IED-related BOLD clusters and ESI estimates. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Adolescent Adult Brain/blood supply Brain/physiopathology Child Electroencephalography/methods Epilepsy/physiopathology Humans Magnetic Resonance Imaging/methods Male Models, Neurological Oxygen/blood signal processing, computer-assisted Synaptic Transmission/physiology Time Factors

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Real diffusion-weighted MRI enabling true signal averaging and increased diffusion contrast

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NEUROIMAGE 2015年 122卷 373-384页

作者： Eichner, Cornelius Cauley, Stephen F. Cohen-Adad, Julien Moeller, Harald E. Turner, Robert Setsompop, Kawin Wald, Lawrence L. Harvard Univ Sch Med Martinos Ctr Biomed Imaging Boston MA USA Max Planck Inst Human Cognit & Brain Sci Leipzig Germany Univ Montreal Ecole Polytech Montreal PQ Canada

This project aims to characterize the impact of underlying noise distributions on diffusion-weighted imaging. The noise floor is a well-known problem for traditional magnitude-based diffusion-weighted MRI (dMRI) data, leading to biased diffusion model fits and inaccurate signal averaging. Here, we introduce a total-variation-based algorithm to eliminate shot-to-shot phase variations of complex-valued diffusion data with the intention to extract real-valued dMRI datasets. The obtained real-valued diffusion data are no longer superimposed by a noise floor but instead by a zero-mean Gaussian noise distribution, yielding dMRI data without signal bias. We acquired high-resolution dMRI data with strong diffusion weighting and, thus, low signal-to-noise ratio. Both the extracted real-valued and traditional magnitude data were compared regarding signal averaging, diffusion model fitting and accuracy in resolving crossing fibers. Our results clearly indicate that real-valued diffusion data enables idealized conditions for signal averaging. Furthermore, the proposed method enables unbiased use of widely employed linear least squares estimators for model fitting and demonstrates an increased sensitivity to detect secondary fiber directions with reduced angular error. The use of phase-corrected, real-valued data for dMRI will therefore help to clear the way for more detailed and accurate studies of white matter microstructure and structural connectivity on a fine scale. (C) 2015 Elsevier Inc. All rights reserved.

关键词： Algorithms Artifacts Brain/anatomy & histology Brain/physiology Diffusion Diffusion Magnetic Resonance Imaging/methods Diffusion Tensor Imaging/methods Diffusion Tensor Imaging/methods Humans Image Enhancement/methods signal processing, computer-assisted signal-To-Noise Ratio

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Single-trial coupling of the gamma-band response and the corresponding BOLD signal

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NEUROIMAGE 2010年第3期49卷 2238-2247页

作者： Mulert, C. Leicht, G. Hepp, P. Kirsch, V. Karch, S. Pogarell, O. Reiser, M. Hegerl, U. Jaeger, L. Moller, H. J. McCarley, R. W. Univ Munich Dept Psychiat & Psychotherapy D-80336 Munich Germany Harvard Univ Dept Psychiat Sch Med Brockton MA 02401 USA VA Boston Healthcare Syst Brockton MA USA Univ Med Ctr Hamburg Eppendorf Ctr Psychosocial Med Dept Psychiat & Psychotherapy Hamburg Germany Univ Munich Inst Clin Radiol D-80336 Munich Germany Univ Leipzig Dept Psychiat & Psychotherapy Leipzig Germany

Oscillations in the gamma-band frequency range have been described to be more closely connected to hemodynamic changes as assessed with functional magnetic resonance imaging (fMRI) than other aspects of neuronal activity. In addition. gamma-band oscillations have attracted much interest during the last few years since they are thought to play a Crucial role in many aspects of brain function related to perception and cognition. It was the aim of the present simultaneous EEG-fMRI Study to identify brain regions specifically involved in the generation of the auditory gamma-band response (GBR) using single-trial coupling of EEG and fMRI. Ten healthy Subjects participated in this study Three different runs of an auditory choice reaction task with increasing difficulty were performed Brain activity was recorded simultaneously with high density FEG (61 channels) and fMRI (1.5 T). BOLD correlates of the GBR have been predicted using the sing-le-trial amplitude of the GBR Reaction times (p<0.001). error rates (p<005) and self-ratings of task difficulty and effort demands (p<0.001) were related to the level of difficulty in the task In addition,we found a significant influence of task difficulty oil the amplitude of the GBR at Cz (p<0.05). Using single-trial Coupling of EEG and fMRI GBR-specific activations were found only in the auditory cortex, the thalamus and the anterior cingulate cortex (ACC) in the most difficult run. Single-trial coupling might be a useful method in order to increase our knowledge about the functional neuroanatomy of "neural ensembles" coupled by 40 Hz oscillations (C) 2009 Elsevier Inc. All rights reserved

关键词： Acoustic Stimulation Adult Brain/anatomy & histology Brain/physiology Brain Mapping/methods Brain Mapping/methods Electroencephalography Evoked Potentials, Auditory/physiology Female Humans Image processing, computer-assisted/methods Magnetic Resonance Imaging Male Neural Pathways/anatomy & histology Neural Pathways/physiology Reaction Time/physiology signal processing, computer-assisted Young Adult

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EPITHELIAL AND CORNEAL THICKNESS MEASUREMENTS BY HIGH-FREQUENCY ULTRASOUND DIGITAL signal-processing

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OPHTHALMOLOGY 1994年第1期101卷 140-146页

作者： REINSTEIN, DZ SILVERMAN, RH RONDEAU, MJ COLEMAN, DJ CORNELL UNIV COLL MEDDEPT OPHTHALMOLNEW YORKNY 10021 CORNELL UNIV COLL MEDMARGARET M DYSON VIS RES INSTNEW YORKNY

Purpose: The authors determine the mean central corneal and epithelial thickness in a group of normal human subjects using a new high-frequency ultrasound technique, incorporating digital signal processing. Method: Both eyes of ten volunteers (age range, 23-44 years) were scanned through a normal saline standoff. Digitized ultrasonic echo data were mathematically transformed to produce a plot, the I-scan, which optimally localizes acoustic interfaces to provide improved measurement precision. System precision was determined by analysis of variance of repeated measures. Central epithelial thickness was obtained by averaging multiple measurements. Central corneal thickness was determined by fitting measurements of apparent corneal thickness in consecutive parallel B-scans to a mathematically modeled cornea. A speed of sound of 1640 m/second was used. Results: Epithelial pachymetric precision using A-scan and I-scan was 4.8 and 2.0 mu m (standard deviation), respectively. The mean epithelial thicknesses for the right and left eyes were 50.7 +/- 3.7 mu m and 50.3 +/- 3.4 mu m, respectively. The mean corneal thicknesses in the right and left eyes were 514.6 +/- 38.4 mu m and 516.2 +/- 37.8 mu m, respectively. The root mean-square differences in epithelial and corneal thickness between the left and right eyes of each subject were 1.3 and 7.7 mu m, respectively (neither was statistically significant). Conclusion: This system provides a pachymetric precision superior to current optical and ultrasound methods. Epithelial and corneal pachymetry is obtained noninvasively by a method that is not limited to optically clear media.

关键词： Adult Anthropometry Cornea/anatomy & histology Cornea/ultrasonography Epithelium/ultrasonography Female Humans Male Reproducibility of Results signal processing, computer-assisted

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