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Medical Devices and Biosensors, 2007. ISSS-MDBS 2007. 4th IEEE/EMBS International Summer School and Symposium on

Date 19-22 Aug. 2007

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    Publication Year: 2007 , Page(s): 1 - 2
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    Publication Year: 2007 , Page(s): 1
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  • [Breaker page]

    Publication Year: 2007 , Page(s): 1
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  • Preface

    Publication Year: 2007 , Page(s): 1
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  • Table of contents

    Publication Year: 2007 , Page(s): I - III
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    Publication Year: 2007 , Page(s): IV
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  • [Society related material]

    Publication Year: 2007 , Page(s): V - VII
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  • [Commentary]

    Publication Year: 2007 , Page(s): 1 - 20
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  • A Novel Calibration Method for Noninvasive Blood Pressure Measurement Using Pulse Transit Time

    Publication Year: 2007 , Page(s): 22 - 24
    Cited by:  Papers (5)  |  Patents (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB) |  | HTML iconHTML  

    This paper proposes a new calibration method for arterial blood pressure (BP) estimation using pulse transit time (PTT). Different from the traditional calibration methods, this new approach features a fast and convenient procedure by modeling the effects on distal arteries of external pressure applied by upper arm cuff. Two rounds of experiments (about two months apart) were conducted on eleven healthy subjects. The results show that the obtained calibration curves can predict the mean BP within 4.5plusmn6.6mmHg of the reference for all the tested subjects during steady state and immediately after exercise. It is also found that the new method has good repeatability within two months. The preliminary results indicate that the new approach has the potential to be used for noninvasive and cuffless measurement of arterial BP in wearable devices. View full abstract»

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  • An oil and water emulsion phantom for biomedical terahertz spectroscopy

    Publication Year: 2007 , Page(s): 25 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2017 KB) |  | HTML iconHTML  

    In order to determine the ability of THz spectroscopy to analyse the composition of biological tissue, a phantom containing combinations of water and lipids was developed. Initially, the absorption coefficient and refractive index of five pure commercially available lipids was measured between 0 and 3 THz. A suitable lipid for phantom manufacture was then chosen and a series of oil-water emulsions were made using surfactants. The lipid content ranged from 0% to 100%. THz spectra of the absorption coefficient and refractive index of these emulsions were measured. Using spectral decomposition techniques based on the Beer Lambert law, the percentage of oil and water in the emulsion was determined. The results show good qualitative agreement with the known compositions. The absolute oil and water content showed a systematic error of 10%. These initial results demonstrate that THz spectroscopy has the potential to determine the composition of biological tissues View full abstract»

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  • Energy Efficient Medium Access Protocol for Wireless Medical Body Area Sensor Networks

    Publication Year: 2007 , Page(s): 29 - 32
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2705 KB) |  | HTML iconHTML  

    This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-slave architecture, where the body-worn slave node periodically sends sensor readings to a central master node. Unlike traditional peer-to-peer wireless sensor networks, the nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor nodes are in standby or sleep mode until the centrally assigned time slot. Once a node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central node and is addressed uniquely to a slave node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more 'flexible' network MAC protocols such as 802.11 or Zigbee. With longer sleep times, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13 um CMOS process. View full abstract»

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  • Micro-Magnetocardiography System with a Single-Chip SQUID Magnetometer Array for QT Analysis and Diagnosis of Myocardial Injury in Small Animals

    Publication Year: 2007 , Page(s): 33 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2678 KB) |  | HTML iconHTML  

    Development of drugs needs electrophysiological studies of small animals like mice, rats or guinea pigs. Electrocardiography (ECG) of hirsute animals is time-consuming. We have developed a micro magnetometer array with 9-channel superconducting quantum interference device (SQUID) with 2.5-mm diameter pickup-coil for non-contact measurement of magnetocardiogram (MCG) in small animals. The micro-MCG successfully recorded PQRST complex in mice, rats and guinea pigs. Regional myocardial injury was made with cryoinjury probe in rat hearts, and the injured pattern in MCG was recorded. Anterior myocardial injury created QS pattern in MCG, and posterior myocardial injury created QR pattern in MCG. Quinidine-induced QT prolongation was successfully detected by micro MCG in mice and rats. Simultaneous recording of ECG and MCG after intraperitoneal administration of quinidine (60 mg/kg) in guinea pigs. Both QTc in ECG and MCG correlated well. Newly developed micro MCG may facilitate the research process of electrophysiological studies of small animals, and may enable high throughput screening of drug-induced QT abnormality. View full abstract»

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  • Deconvolution of Skin Images with Multivariate Curve Resolution

    Publication Year: 2007 , Page(s): 36 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3369 KB) |  | HTML iconHTML  

    Two-photon fluorescence microscopy has been demonstrated as a high-resolution 3-D tissue imaging technique. If the dream of a noninvasive optical biopsy is to be realized upon this technology, biochemically relevant information must be extracted from the data thus obtained. The current study investigated the ability of different Gram-Schmidt modifications to orthogonal projection multivariate curve resolution (MCR) to find the emission spectra and distributions of fluorophores in volume images. A two-photon microscope, incorporating a high-power femtosecond Ti:Sapphire laser and a high sensitivity multianode photomultiplier spectrally resolved detector, was used to obtain spectroscopic data for each point in a volume of the sample. The MCR algorithm was developed and tested by first examining fluorescent beads. MCR analysis on images obtained from ex vivo human skin provided recognizable structural resolution with no a priori information, suggesting that the resolved spectra correspond to different endogenous fluorophores. View full abstract»

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  • Effects of wrist oscillations on contralateral neurological postural tremor using a new myohaptic device ('wristalyzer')

    Publication Year: 2007 , Page(s): 44 - 48
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3804 KB) |  | HTML iconHTML  

    Upper limb postural tremor consists of distinct oscillations, mainly mechanical-reflex and central-neurogenic. These oscillations are superimposed upon a background of irregular fluctuations in muscle force. Muscle spindles play key-roles in the information flow to supra-spinal and spinal generators. Oscillations were delivered using a new generation portable myohaptic device, called 'wristalyzer', which takes into account the ergonomy of upper limbs allowing a fine adjustment to each configuration of upper limb segments. The nominal torque of the device is 4 Nm, with a maximal rotation velocity of 300 degrees/s and a range of motion of +45 to -45 degrees. Reliability was assessed in basal condition and during loading conditions. We assessed the effects of wrist oscillations upon contralateral postural tremor in 6 control subjects and in 7 neurological patients exhibiting a postural tremor in upper limbs. Patients exhibited an increased variability of postural tremor during fast oscillations (13.3 Hz). One patient with overactivity of the olivocerebellar pathways exhibited a drop in the peak frequency of more than 20 %. The relative power of the 8-12 Hz subband was significantly higher in controls both in basal condition and during oscillations (p = 0.028 and p = 0.015, respectively). This new device could be used to increase our knowledge of the responsiveness of tremor generators to stimulation of muscle spindles. It has also several potential applications for telemedicine in neurological rehabilitation. View full abstract»

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  • Closed loop glucose control in critical care patients: Previous study for clinical essays

    Publication Year: 2007 , Page(s): 49 - 52
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    The feasibility of the design of a closed loop system to control glucose levels in critical care patients is presented in this paper. Considering the basic elements for its construction: The plasma glucose detection using a subcutaneous sensor and a Kalman filter, the model of glucose metabolism, and having special consideration in the method to calculate the optimal insulin infusion designing classical control schemes (PID and PI) and a GPC (predictive controller). View full abstract»

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  • A low power CMOS front-end for photoplethysmongraphic signal acquisition with robust DC Photocurrent Rejection

    Publication Year: 2007 , Page(s): 53 - 56
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3066 KB) |  | HTML iconHTML  

    A micro-power CMOS front-end for photoplethysmographic signal (PPG) acquisition is presented. The circuit is composed of a transimpedance amplifier (TIA), post amplifier and low-pass filter. The TIA is configured with a sample-and-hold (S/H), an error amplifier and a current-sink transistor in feedback to reject DC photocurrent generated from photodiode, which varies from person to person. To reduce power consumption, the LED is pulsed and thus the input to the TIA is a modulated current pulse. The low-pass filter is implemented by using the current-steering technique (CST). The proposed circuit is designed to generate PPG waveform with a fixed DC output to prevent signal saturation by rejecting the input pulsating DC photocurrent from modulated signal. Experimental results show that the circuit works properly from a 2.5-V power supply with a bandpass frequency from 0.1 Hz to 6.5 Hz and has a rejection range from 0.1 muA to 53.6 muA. View full abstract»

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  • Image Denoising in Curvelet Transform Domain Using Gaussian Mixture Model with Local Parameters for Distribution of Noise-Free Coefficients

    Publication Year: 2007 , Page(s): 57 - 60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2926 KB) |  | HTML iconHTML  

    This paper proposes a new statistical model for curvelet coefficients of images to characterize both leptokurtic behavior and spatially clustering property of them. We employ a mixture of Gaussian probability density functions (pdfs) with local parameter to model the distribution of noise-free curvelet coefficients. This pdf is mixture and so it is able to model the heavy-tailed nature of curvelet coefficients. Since we use local parameters for mixture model, the proposed pdf can capture the clustering property of curvelet coefficients in spatial adjacent. This model is employed for noise reduction in a Bayesian framework using maximum a posteriori (MAP) estimator. We examine this method for denoising of several grayscale images such as CT image corrupted with additive Gaussian noise in various noise levels. The simulation results show that the proposed method has better performance visually and in terms of peek signal-to-noise ratio (PSNR) from several denoising methods in wavelet and curvelet domain. View full abstract»

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  • Correlation of Facial Infrared Thermograph and Carotid Stenosis

    Publication Year: 2007 , Page(s): 61 - 64
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2952 KB) |  | HTML iconHTML  

    Facial temperature distribution is affected by blood flow supply, which is compromised in carotid stenosis. Therefore we conducted a study to compare the parameters of infrared thermograph of face and the result of simultaneous carotid angiography. Totally 26 consecutive patients underwent carotid digital subtraction angiography and the patency of common, external, and internal carotid was measured according to the principle of North American Symptomatic Carotid Endarterectomy Trial . All the stenotic lesions detected were recorded as ECAS for external carotid stenosis, CCAS for common carotid stenosis, and ICAS for internal carotid stenosis. On the other hand, infrared thermograph of bilateral facial sides of the particiants was taken as well. Using a computerized programmatic strategy, the raw image data were processed to calculate the mean temperature and the standard deviation of each side of the 26 patients. In 52 samples (both sides of 26 patients)of this study, there are 29 (55.8%) CCAS, 25 ( 48.1%)ECAS, and 31 ( 59.6%)ICAS. The mean temperature of all 52 samples is 32.72 +/-1.19 degree Celsius, and the average standard deviation of all the samples is 2.01 +/-1.10 degree Celsius. The mean temperature of the ECAS group is significantly lower than that of non-ECAS group (32.33+/-1.03 versus 33.08+/-1.24degC, p=0.022), and the standard deviation of the facial temperature distribution is also lower in the CCAS patients (1.68+/-1.09 versus 2.31+/-1.04degC, p=0.037). In contrast, the ICAS group has the higher mean facial temperature (33.06 +/-1.02 versus 32.22 +/-1.28, p=0.012) (Figure 9), and higher standard deviation of the facial temperature distribution (2.27+/-1.12 versus 1.62+/-0.97, p=0.036) than the non-ICAS patients. The mean temperature and the standard deviation of facial infrared thermograph are significantly associated with carotid stenosis. Such an approach might give a light on the development of the fast screening method of carotid stenosis. View full abstract»

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  • MR Based Polymer Gel Dosimetry (MRPD) versus Film Dosimetry using Dose Modulation Transfer Function (DMTF)

    Publication Year: 2007 , Page(s): 65 - 68
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3114 KB) |  | HTML iconHTML  

    Precise methods of modern radiation therapy such as intensity modulated radiotherapy (IMRT), brachytherapy (BT) and high LET irradiation allow for high dose localization in volumes of a few mm3. However, most dosimetry methods-ionization chambers, TLD arrangements or silicon detectors, for example-are not capable of detecting sub-mm dose variations or do not allow for simple dose imaging. Magnetic resonance based polymer dosimetry (MRPD) appears to be well suited to three-dimensional high resolution relative dosimetry but the spatial resolution based on a systematic modulation transfer function (MTF) approach has not yet been investigated. In this study a theoretical construct for addressing the spatial resolution in different dose imaging systems, i.e. the dose modulation transfer function (DMTF) approach, have been used. The absorption grid is made of brass, which offers a good compromise between effective absorption necessary to obtain sufficient modulation and easy mechanical processing to obtain the fine grid structures. Quasi-periodic slits at lateral width of about 280, 525 and 1125 mum were sawed by means of fine saw blades in the 8 mm thick brass absorber material. The modulated dose is detected by the polymer gel and then, for film dosimetry the polymer gel is replaced by a film layer which was located under the absorption grid. We concluded that the DMTF in high frequencies is related to the imaging system, and with the current imaging system the spatial resolution in film densitometry and MRPD for 280 mum resolution is nearly the same. View full abstract»

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  • Prognostic Value of Brain Tissue Pathological Changes in Patients with Multiple Sclerosis Using Magnetization Transfer Parameters

    Publication Year: 2007 , Page(s): 69 - 72
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    The aim of this study is to investigate abnormalities and characterize pathologic changes associated with demyelination in the brain tissue of patients with multiple sclerosis (MS). In this method, magnetization transfer parameters such as magnetization transfer ratio (MTR), magnetization transfer rate (Ksat) and native relaxation time of brain tissue with and without applying saturation pulse were determined (Tlfree , Tlsat). Measurements were performed with segmentation regional measurements and histogram analysis. It had been shown that individual valuables contributing to magnetization transfer process can be provide further insight into the mechanisms of myeline destruction in multiple sclerosis disease. Conventional MR imaging protocols such as T1-weighted, T2-weighted, T2-FLAIR as well as MT-3DSPGR images were performed on five MS patients and five normal subjects. White matter and lesion masks were segmented from T2-weighted images and superimposed on MT parameter maps using FSL software. MTI parameters of lesions and normal appearing white matter (NAWM) were analyzed in comparison with those of normal volunteers. The MTR histograms of white matter were also generated for patient and normal subjects. A significant reduction was found in mean MTR and Ksat parameters with an increase of T1free and T1sat values in patient white matters and lesions in comparison with normal controls. A significant reduction was found in white matter MTR histogram height and position accompanied with a total shift to the left between MS patients and healthy subjects. Significant reduction in NAWM-MTI parameters of MS patients compared to normal subjects, shows that pathological changes occur outside visible lesions on conventional MR images among patients with multiple sclerosis. Quantitative MT imaging can help to evaluate the extent of global damage in the brain tissue. View full abstract»

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  • An in Vivo Acquisition Device for Near Infrared Blood Spectra

    Publication Year: 2007 , Page(s): 73 - 76
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    The near infrared spectroscopy for the noninvasive determination of blood compositions has attracted significant interest in recent years. Lately the Dynamic Spectroscopy (DS), a new device for artery blood compositions detecting is introduced. It can eliminate the interferences of individual discrepancy and measurement conditions. But acquisition of the spectrum meeting the accuracy of blood compositions analysis is a bottleneck to be resolved. In this article, a new acquisition device of dynamic spectrum is present. On the hardware side, logarithmic amplifier is used to convert the photoelectric pulse wave to the logarithmic pulse wave. This modification compresses the dynamic range of the system and reduced the cost of the signal picking device. On the software side, based on the fast Fourier Transform (FFT) algorithm, the calculating of the peak to peak value of the photoelectric pulse wave in the time domain is converted to the extracting of the fundamental components of the logarithmic pulse wave. Due to the plus function of FFT to the signal to noise ratio (SNR), the resolution of the spectrum analysis is improved. View full abstract»

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  • Study on the Responses of Hypertensive Patients to Music

    Publication Year: 2007 , Page(s): 77 - 78
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1262 KB) |  | HTML iconHTML  

    Many clinical findings indicate that certain types of music can reduce blood pressure (BP) under various medical conditions. Therefore, it is of great interest to investigate the BP responses of hypertensive patients to music and to what extent the music can help them to lower their BP if they listen to the selected music daily. Fifteen subjects from an elderly home participated in the study. Eight of them had initial systolic BP (SBP) higher than 140 mmHg. They listened to the selected music for 25 minutes per day for 4 weeks. BP was measured twice a week by a registered nurse with a sphygmomanometer during the 4-week study period and after the completion of the study. Three subjects, including one with initial SBP higher than 140 mmHg, dropped during the experiment due to changes of medical conditions or personal reasons. After 4 weeks, the average decrease in SBP and diastolic BP (DBP) was 11.8 mmHg (p=0.008) and 4.7 mmHg (p=0.218) (n=12), respectively. For the subgroup of subjects with initial SBP higher than 140 mmHg, the average decrease in SBP and DBP was 19.9 mmHg (p<0.001) and 8.5 mmHg (p=0.087) (n=7), respectively. The results demonstrated that listening to a certain type of music may serve as an alternative method to reduce high SBP and the responses of hypertensive patients to music depend on the baseline BP. View full abstract»

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  • A Novel MAC Protocol for Wireless Physiological Information Sensor Network

    Publication Year: 2007 , Page(s): 79 - 81
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    A wireless physiological information network (WPISN) is used to monitor multiple kinds of physiological information on a patient while allowing the patient to move as usual. In the building of a WPISN, design of communication protocols, especially the MAC protocol, is key to make the whole network work. A novel low power MAC protocol for WPISNs is presented. It avoids power consuming during idle listening, collision and overhearing, thus prolongs the lifetime of a battery-equipped sensor node. Operating time slots can be dynamically adjusted according to different tasks. Also a time synchronization method is designed for the medical center and nodes in a WPISN, providing precise time for MAC protocol implementation. View full abstract»

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  • Reverse Middle Ear Transfer Function Based Estimation of Transient Evoked Otoacoustic Emission

    Publication Year: 2007 , Page(s): 82 - 85
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    Otoacoustic emission is low-level acoustic signal generated in cochlea and could be measured with sensitive probe in the outer ear canal. Since it was believed that the outer hair cells are the origin of otoacoustic emission and this sound is transmitted through oval window to outer ear canal, the distortion effect of middle ear and outer ear on recorded signal is inevitable. For estimating the original otoacoustic emission the compensation of middle ear and outer ear effect are very important. The computational model of the auditory periphery is used to design a compensation filter for the estimation of the otoacoustic emission before entering the middle ear. The results of comparison of estimated signal with recorded one indicated that assessment based on estimated otoacoustic emission is much more closer to real response of outer hair cells . View full abstract»

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