2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)最新文献

{"title":"Vascular segmentation in magnetic resonance angiography: A modified region growing approach","authors":"M. Almi'ani, B. Barkana","doi":"10.1109/SPMB.2012.6469450","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469450","url":null,"abstract":"A modified region growing algorithm is proposed to extract cerebral vessels using a magnetic resonance angiography (MRA) database. To improve the performance of the image segmentation method, as a pre-processing step, image enhancement methods are applied by the gamma correction technique and spatial operations. This step improves the detection of gray-level discontinuities in MRA images. The traditional region growing method is modified by extending the neighborhood as 24 pixels and by defining a filling protocol to label vascular structure. The performance of the proposed algorithm is compared with that of the traditional region growing method and four other segmentation methods. The minimum and maximum errors of the modified region growing algorithm is calculated as zero and 1.11%, respectively while the traditional region growing method has 0.2% and 7.81%.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"2000 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126032730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An implementation of the EM algorithm in white matter fiber tract clustering","authors":"Xuwei Liang","doi":"10.1109/SPMB.2012.6469457","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469457","url":null,"abstract":"Automatic unsupervised clustering of white matter fiber tracts is necessary for the group analysis of brain neural network integrity using diffusion tensor imaging (DTI) and DTI tractography techniques. In this paper, we present an implementation of the expectation-maximization (EM) algorithm to conduct the automatic unsupervised clustering of reconstructed white matter fiber tracts in DTI. The statistical model is the multivariate and multi-mode Gaussian mixture which depicts the probability distribution of white matter fiber tracts. Issues related to the parameter estimation, initialization, and convergence for applying the EM algorithm in the context of the white matter fiber tract clustering are discussed in detail. Comparisons of the EM algorithm with the K-means approach are also performed. The difference between the fixed and variant prior probabilities on the clustering result as the EM algorithm proceeds is demonstrated by experiments. Real DTI datasets are used to evaluate the performance of the proposed method. Experimental results show that the proposed approach is feasible and may be useful in the automatic unsupervised clustering of white matter fiber tracts.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116617671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resiliency analysis and modeling for real-time cardiovascular diagnostic devices","authors":"R. Ledesma, Zhanpeng Jin","doi":"10.1109/SPMB.2012.6469456","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469456","url":null,"abstract":"To address the increasing severe challenges with regard to the reliability of medical devices, in this study we propose to investigate the resilience and vulnerability of cardiovascular diagnostic devices as a case study, by using a formal fault injection approach. We develop a generalized model of the ECG-based heart disease detection system using MATLAB/Simulink, which consists of heartbeat detection and classification. Furthermore, we propose a configurable fault generator (FG) to emulate a wide variety of accidential faults occuring within the developed system, to help us explore and understand the most critical data-paths and processing modules, where any faults or unexpected perturbations will cause dramatic impacts on the system accuracy and performance, or even result in system crash in real case.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114084549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a method for early detection of congestive heart failure with an electrocardiogram and acoustic transducers","authors":"A. Kaiser, C. Pocock, P. Sharma, N. Browdues, K. Newman, F. Barnes","doi":"10.1109/SPMB.2012.6469460","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469460","url":null,"abstract":"In an effort to improve the reliability of the detection of congestive heart failure, a method utilizing phase shifts of cardiac and thoracic acoustics coupled with ECG signals is described. The system consists of bipolar ECG electrodes placed on the pectoral muscles and acoustic transducers that monitor four locations across the chest and back. The method is tested on six healthy individuals; there are five males and one female. Amplitude of the acoustic and electric signals vary significantly so spectral analysis is utilized for classification. Frequency analysis of the data shows expected values for healthy individuals. For this initial set of data, cardiac acoustic responses are below 400 Hz. It is expected in patients with congestive heart failure to have frequency responses far beyond 400 Hz. This is due to a “crackle” sound that is produced in the lungs as a result of pleural effusion. It is also anticipated to see significant differences in phase shifts among healthy individuals versus individuals with congestive heart failure.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117182830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study of kernel CSP-based motor imagery brain computer interface classification","authors":"H. Albalawi, Xiaomu Song","doi":"10.1109/SPMB.2012.6469465","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469465","url":null,"abstract":"The Common Spatial Patterns (CSP) method is a widely used spatial filtering technique that can extract discriminative features for Electroencephalogram (EEG)-based brain computer interface (BCI) classification tasks. Since the EEG signal acquired on the scalp is a nonlinear composition of multiple signal and noise sources, in order to characterize the nonlinear data structure, nonlinear CSP methods have been proposed by using the kernel technique. Most kernel CSP methods calculate temporal covariance structure in a kernel feature space that leads to a large kernel matrix with each dimension equal to the number of time points multiplied by the number of classes. In this work, a kernel CSP method exploiting spatial covariance structure in the feature space is developed where the size of kernel matrix is the number of EEG channels, which is usually much less than that of time points. The proposed method was evaluated using motor imagery EEG data. Results indicate that the kernel CSP using spatial analysis can provide comparable performance to the existing methods using temporal analysis with less computational load.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131842860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radial k-space acquisition improves robustness of MR-based attenuation maps for MR/PET quantification in an animal imaging study of the abdomen","authors":"J. Bini, P. Robson, C. Calcagno, A. Millon, M. Lobatto, Z. Fayad","doi":"10.1109/SPMB.2012.6469451","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469451","url":null,"abstract":"One of the most important steps in positron emission tomography (PET) is the correction of photon attenuation for accurate quantitative PET. Currently, FDA approved clinical MR/PET systems employ segmentation of conventional, low resolution, gradient echo (GRE) based, T1-weighted MR images to generate maps for MR-based attenuation correction (MRAC). However, these acquisitions are optimized for imaging human subjects and exhibit artifacts when used in preclinical MR/PET studies. Pronounced breathing artifacts in animal models used for preclinical imaging, impede accurate segmentation for generation of attenuation maps, impacting quantitative measurements of reconstructed PET images. We propose a radial k-space acquisition sequence designed to redistribute coherent breathing artifacts that result from Cartesian k-space trajectories into incoherent pseudo-noise spread across the image domain. PET data from five rabbits was reconstructed using the system standard MR-derived attenuation map with segmentation errors, due to breathing artifacts in the Cartesian acquisition (cartMR map), the manually segmented MR-derived attenuation map (msegMR map) and the radially acquired MR sequence used to generate an attenuation map from the system standard segmentation algorithm (radMR map). The resulting attenuation corrected PET data sets (PETcartMRmap, PETmsegMRmap, and PETradMRmap) were then qualitatively and quantitatively evaluated. Voxel-by-voxel comparison of PET values for all five rabbits showed excellent correlation between PETmsegMRmap and PETradMRmap SUV values (R=0.999, p0.0001). Bland-Altman plots showed that the mean of the difference of SUVs between PETmsegMRmap and PETradMRmap voxels for all five rabbits was 0.53% (0.004±0.014SD). Region-of-interest-based comparison showed that PETradMRmap and PETmsegMRmap methods differ in SUVmean by -0.7% to 0.9% and SUVmax by -1.2% to 2.7%. Employing a radial k-space MR acquisition during preclinical MR/PET protocols facilitates highly accurate segmentation and PET quantification, without the need for subjective user input and is therefore, better suited for use in preclinical MR/PET protocols than the existing MR Cartesian acquisition.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131620492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping subcortical connectivity related to cortical gamma and theta oscillations","authors":"T. Ellmore, K. Tertel, N. Dias, N. Tandon","doi":"10.1109/SPMB.2012.6469452","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469452","url":null,"abstract":"An open problem in signal processing and bioimaging involves the development of techniques to localize the circuits that subserve neural oscillations in the living human brain. This is an important challenge for basic and translational neuroscience since frequency-specific rhythms are hypothesized to code for sensorimotor and cognitive processes and aberrations in these rhythms develop as early markers of pathology in disorders such as epilepsy and Parkinson's disease. Methods to reconstruct the subcortical white matter networks related to different frequency bands have been limited by the dual challenges of recording electrical activity directly from human cortex with high spatial resolution and the inability, until a decade ago, to map white matter connectivity in vivo. In the present study, a multi-modal fusion of electrocorticography (ECoG) and diffusion tensor imaging (DTI) tractography data collected from 9 neurosurgical patients performing a working memory task known to elicit robust distributed cortical gamma and theta oscillations is presented. A similarity analysis of connectivity underlying 629 intracranial electrodes revealed distinct patterns of white matter terminating near cortex that exhibited gamma, theta, and conjoint gamma and theta oscillatory power. Future applications of this method for parcellating neural circuitry in normal and pathological states are discussed.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115554141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transfer entropy between cortical and basal ganglia electrophysiology","authors":"T. Gilmour, C. Lagoa, W. Jenkins, Anand N. Rao, M. Berk, K. Venkiteswaran, T. Subramanian","doi":"10.1109/SPMB.2012.6469453","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469453","url":null,"abstract":"Linear measures such as cross-correlation, coherence, and directed transfer functions have previously been applied to investigate the functional connectivity between brain regions. However, such methods do not account for nonlinear interactions between the signals. Separately, dopaminergic cell transplants have been shown to provide symptomatic amelioration and partial electrophysiological normalization of aberrant basal ganglia firing patterns in Parkinson's Disease. However, the precise extent and mechanisms of basal ganglia electrophysiological normalization have remained unclear. In this experiment we computed the transfer entropy between electroencephalograms (EEGs) and basal ganglia local field potentials (LFPs) from urethane-anesthetized rats, in order to investigate both linear and nonlinear interactions. We used the 6-hydroxy-dopamine lesioned medial forebrain bundle hemiparkinsonian (HP) rat model, and recorded from the substantia nigra and subthalamic nucleus of normal rats, HP rats, and HP rats with murine fetal ventral mesencephalic cell transplants, looking separately at slow wave EEG epochs versus global activation epochs. We found that both the crosscorrelation and the transfer entropy between the motor cortical EEG and basal ganglia LFPs was increased in the HP group (p<;0.05) and returned to normal levels in the grafted group, in most nuclei and conditions. However, the transfer entropy more robustly showed the difference between the groups. Our findings indicate that transfer entropy is a sensitive tool for nonlinear inter-nucleic functional connectivity analyses, and demonstrate the novel restorative ability of dopaminergic grafts for the parkinsonian basal ganglia electrophysiology.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133686382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive circadian rhythm estimator and its application to locomotor activity","authors":"Jiaxiang Zhang, J. Wen, A. Julius","doi":"10.1109/SPMB.2012.6469471","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469471","url":null,"abstract":"Disruption of the circadian rhythm is detrimental to human well being, with consequences ranging from lower productivity, sleep disorder, to more serious health problems. Accurate estimation of circadian rhythm is critical to the assessment and treatment of circadian disruption. Circadian estimate is also essential for light-based circadian entrainment. Direct measurements of circadian rhythm markers such as dim light melatonin onset are inconvenient and acquired at best at low rate. Wearable continuous measurements such as actigraph and body temperature are convenient but masked by many other factors. In this paper, we present a new circadian rhythm estimation scheme based on adaptive notch filter (ANF) which is commonly used in signal processing. The ANF is designed to track the gain and phase of a single sinusoid from noisy data. We extend the classic ANF to multiple harmonics with non-zero bias needed in circadian rhythm tracking. The modified ANF is tested on rat and Drosophila locomotor activity data to extract circadian argument. The estimation results are compared with linear regression and gliding cosinor. The ability to generate circadian estimate opens up the tantalizing possibility of personalized circadian rhythm estimator and light therapy.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127404994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mobile robot navigation through a brain computer interface","authors":"Yih-Choung Yu, A. Nawroj, Siyuan Wang, L. Gabel","doi":"10.1109/SPMB.2012.6469469","DOIUrl":"https://doi.org/10.1109/SPMB.2012.6469469","url":null,"abstract":"A brain computer interface (BCI) has been developed to navigate a robot by way of the operator's brain activities. The navigation commands were displayed on a computer screen to interact with the operator. While the operator was giving the navigation command by “thinking”, his/her EEG signals were acquired by a data acquisition system through the EEG leads. The EEG signals were analyzed to identify the P300 response of the operator, and thus determine the operator's navigation command. This command was then transmitted through a local area network to guide the robot. Feasibility of this robot navigation scheme was successfully tested with a virtual robot on a computer. The entire concept will be implemented and tested in hardware in the near future.","PeriodicalId":300561,"journal":{"name":"2012 IEEE Signal Processing in Medicine and Biology Symposium (SPMB)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128842729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}