Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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Conf Proc IEEE Eng Med Biol Soc · Jan 2013
Influence of the anisotropic mechanical properties of the skull in low-intensity focused ultrasound towards neuromodulation of the brain.
Lately, neuromodulation of the brain is considered one of the promising applications of ultrasound technology in which low-intensity focused ultrasound (LIFU) is used noninvasively to excite or inhibit neuronal activity. In LIFU, one of critical barriers in the propagation of ultrasound wave is the skull, which is known to be highly anisotropic mechanically: this affects the ultrasound focusing, thereby neuromodulation effects. ⋯ Our results show that though most of the pressure that reaches to the brain is due to the longitudinal wave propagation through the skull, the normal stress in the transverse direction of the wave propagation has the main role to control the pressure profile inside the brain more than the shear stress. The results also show that the anisotropic properties of skull contribute in broadening the focal zone in comparison to that of the isotropic skull.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2013
Tracking progression of patient state of health in critical care using inferred shared dynamics in physiological time series.
Physiologic systems generate complex dynamics in their output signals that reflect the changing state of the underlying control systems. In this work, we used a switching vector autoregressive (switching VAR) framework to systematically learn and identify a collection of vital sign dynamics, which can possibly be recurrent within the same patient and shared across the entire cohort. We show that these dynamical behaviors can be used to characterize and elucidate the progression of patients' states of health over time. Using the mean arterial blood pressure time series of 337 ICU patients during the first 24 hours of their ICU stays, we demonstrated that the learned dynamics from as early as the first 8 hours of patients' ICU stays can achieve similar hospital mortality prediction performance as the well-known SAPS-I acuity scores, suggesting that the discovered latent dynamics structure may yield more timely insights into the progression of a patient's state of health than the traditional snapshot-based acuity scores.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2013
Seizure detection methods using a cascade architecture for real-time implantable devices.
Implantable high-accuracy, and low-power seizure detection is a challenge. In this paper, we propose a cascade architecture to combine different seizure detection algorithms to optimize power and accuracy of the overall seizure detection system. ⋯ In the second-stage detector-and only for the seizure candidates detected in the first detector-a high-accuracy algorithm is used to eliminate the false positives. We show that the proposed cascade architecture can reduce power consumption of seizure detection by 80% with high accuracy, offering a suitable option for real-time implantable seizure detectors.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2013
Control of rapid hypothermia induction by total liquid ventilation: preliminary results.
Mild therapeutic hypothermia (MTH) consists in cooling the body temperature of a patient to between 32 and 34 °C. This technique helps to preserve tissues and neurological functions in multi-organ failure by preventing ischemic injury. Total liquid ventilation (TLV) ensures gas exchange in the lungs with a liquid, typically perfluorocarbon (PFC). ⋯ MTH could be reached safely in 3 minutes at the femoral artery, in 3.6 minutes at the esophagus, in 7.7 minutes at the eardrum and in 15 minutes at the rectum. All temperatures were stable at 33.5 ± 0.5 °C within 15 minutes. The present results reveal that ultra-fast MTH induction by TLV with Inolivent-5.0 is safe for the heart while maintaining esophageal and arterial temperature over 32.6 °C.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2013
Analysis of adventitious lung sounds originating from pulmonary tuberculosis.
Tuberculosis is a common and potentially deadly infectious disease, usually affecting the respiratory system and causing the sound properties of symptomatic infected lungs to differ from non-infected lungs. Auscultation is often ruled out as a reliable diagnostic technique for TB due to the random distribution of the infection and the varying severity of damage to the lungs. However, advancements in signal processing techniques for respiratory sounds can improve the potential of auscultation far beyond the capabilities of the conventional mechanical stethoscope. ⋯ These features were then employed to train a neural network to automatically classify the auscultation recordings into their respective healthy or TB-origin categories. The neural network yielded a diagnostic accuracy of 73%, but it is believed that automated filtering of the noise in the clinics, more training samples and perhaps other signal processing methods can improve the results of future studies. This work demonstrates the potential of computer-aided auscultation as an aid for the diagnosis and treatment of TB.