The purpose of this study was to evaluate a portable tool for use by first responders in document... more The purpose of this study was to evaluate a portable tool for use by first responders in documenting triage of victims in a mass casualty incident (MCI) more effectively. The tool presented in this study allows first responders to gather patients vital signs, injuries, and triage status in a prompt and accurate way, and enables first responders to wirelessly communicate vital health information throughout the entire care continuum. The architecture infrastructure for the portable device is called Triage and Casualty Informatics Technology (TACIT) and can expedite triage, transport and treatment procedures within an MCI. TACIT was developed by integrating handheld devices, wireless networks, global positioning system (GPS), digital cameras, and bar code scanners with customized triage software. Two MCI initial field trials verified that the TACIT software, battery life, data accuracy, and wireless transmission met the emergency response system requirements. Initial field trials also demonstrated robustness of operation, reduced triage collection time and improved collection accuracy. The TACIT system could work as an efficient prehospital response tool and platform.
Mental practice using motor imagery of limb movement may facilitate motor recovery in persons who... more Mental practice using motor imagery of limb movement may facilitate motor recovery in persons who have experienced cerebrovascular accident (CVA). However, the lack of a feedback mechanism that can monitor the quality of the motor imagery affects patients' engagement and motivation to participate in the mental practice training program. This study investigates the effect of novel real-time motor imagery-associated cortical activity feedback on motor imagery-based mental practice training. Ten healthy volunteers were randomly assigned into intervention and control groups. Both groups participated in a five-visit motor imagery-based mental practice training program managed over a period of two months. The intervention group received mental practice training with real-time feedback of movement-associated cortical activity-beta band (16-28 Hz) event-related desynchronization (ERD) in electroencephalography (EEG), using a novel custom-made brain-computer interface (BCI) system. The c...
Evoked potentials (EPs) to noxious thermal stimulation of skin may provide information about inte... more Evoked potentials (EPs) to noxious thermal stimulation of skin may provide information about integrity of the nociceptive afferent system and thus small afferent fiber integrity. Here we describe subjective report, EPs and response times to noxious contact thermal and laser stimuli in the same subjects. Pain quality to both forms of stimulation was consistently reported as a brief pricking or stinging sensation (first pain), occasionally followed, after a silent period, by a diffuse burning sensation (second pain). EPs to laser generated heat pulses consisted of bi- or triphasic waveforms with a large positive wave at approximately 300 ms following arm stimulation and 360 ms following stimulation of the leg. EPs to contact heat pulses consisted of a single, scalp positive wave occurring approximately 830 ms following arm stimulation and 890 ms following leg stimulation. Both forms of noxious stimulation activated afferents with a conduction velocity consistent with that of A-delta f...
A high frequency scanning acoustic microscope (SAM) operating at 1-1.3 GHz was used to investigat... more A high frequency scanning acoustic microscope (SAM) operating at 1-1.3 GHz was used to investigate subsurface defects in diamond-like carbon (DLC) films that were 2-3 μm thick. Because the wavelength of the longitudinal wave in the film was comparable to the film thickness, the acoustical images obtained were near-field images. To interpret the features in the acoustical images, a multidisciplinary
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
This study aims to explore whether human intentions to move or cease to move right and left hands... more This study aims to explore whether human intentions to move or cease to move right and left hands can provide four spatiotemporal patterns in single-trial non-invasive EEG signals to achieve a two-dimensional cursor control. Subjects performed motor tasks by either physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored to support accurate computer pattern recognition. The performance was evaluated by both offline classification and online two-dimensional cursor control. Event-related desynchronization (ERD) and post-movement event-related synchronization (ERS) were observed on the contralateral hemisphere to the moving hand for both physical movement and motor imagery. The offline classification of four motor tasks provided 10-fold cross-validation accuracy as high as 88% for physical movement and 73% for motor imagery. Subjects participating in experiments with physical movement were able to complete the...
We evaluated evoked potentials (EPs) to noxious contact heat pulses delivered to hairy skin of he... more We evaluated evoked potentials (EPs) to noxious contact heat pulses delivered to hairy skin of healthy adults. Heat pulses from an adapting temperature of 34 degrees C to a target temperature of 52 degrees C, produced two scalp positive waves. The first peaked at 44 degrees to 45 degrees C (approximately 500 ms following stimulus onset), while the second peaked approximately 300 ms following the 52 degrees C heat pulse (approximately 1 s after stimulus onset). The first positive wave was absent from an adapting temperature of 39 degrees C, suggesting loss of synchronized activation of warm and/or low threshold mechanothermal afferents. The second EP was observed following stimulation from both adapting temperatures and was associated with subjective report of first pain. Latency difference of the pain EP from arm and leg were consistent with conduction in Adelta nociceptive afferents (approximately 10/ms). EPs to painful contact thermal stimuli may be of value in the evaluation of small fiber peripheral neuropathies and assessment of altered pain states.
The purpose of this study was to evaluate a portable tool for use by first responders in document... more The purpose of this study was to evaluate a portable tool for use by first responders in documenting triage of victims in a mass casualty incident (MCI) more effectively. The tool presented in this study allows first responders to gather patients vital signs, injuries, and triage status in a prompt and accurate way, and enables first responders to wirelessly communicate vital health information throughout the entire care continuum. The architecture infrastructure for the portable device is called Triage and Casualty Informatics Technology (TACIT) and can expedite triage, transport and treatment procedures within an MCI. TACIT was developed by integrating handheld devices, wireless networks, global positioning system (GPS), digital cameras, and bar code scanners with customized triage software. Two MCI initial field trials verified that the TACIT software, battery life, data accuracy, and wireless transmission met the emergency response system requirements. Initial field trials also demonstrated robustness of operation, reduced triage collection time and improved collection accuracy. The TACIT system could work as an efficient prehospital response tool and platform.
Journal of Biomechanical Engineering-transactions of The Asme, 1988
A time-of-flight MRI velocity measurement technique is evaluated against corresponding LDV measur... more A time-of-flight MRI velocity measurement technique is evaluated against corresponding LDV measurements in a constriction tube model over a range of physiologic flow conditions. Results from this study show that MR displacement images can: 1) be obtained within both laminar and turbulent jets (maximum stenotic Re approximately equal to 4,200), 2) measure mean jet velocities up to 172 cm/s, and, 3) detect low forward and reverse stenosis (0 less than or equal to L/D less than or equal to 2). Regions between the jet termination point and re-establishment of laminar flow (Re greater than or equal to 1500, greater than or equal to 1000, and greater than or equal to 110 downstream of 40, 60, and 80 percent stenosis, respectively) cannot presently be detected by this technique.
A 1D MR sequence has been developed for determining aortic flow wave velocity (WV), a metric of a... more A 1D MR sequence has been developed for determining aortic flow wave velocity (WV), a metric of arterial compliance, within a single cardiac cycle. Studies were carried out on the thoracic aortas of 10 normal volunteers. Correlative WV data were also acquired from each subject using a conventional phase-veloc- ity 2D mapping technique. Aortic WV in this cohort was found
A MR method is presented for measuring pulse wave velocity (PWV) and its application to assessing... more A MR method is presented for measuring pulse wave velocity (PWV) and its application to assessing stiffness in the human thoracic aorta. This one-dimensional (1D) flow displacement method applies a single RF comb excitation to the vessel, followed by an oscillating frequency encoding gradient, each oscillation providing a 1D projection of the vessel, enabling one to track fluid motion. The currently implemented sequence excites nine slices within a 20-cm length of vessel and has a temporal resolution of 2.03 msec and a total acquisition time of 140 msec. Offline-reconstructed position-versus-time plots show curvilinear flow displacement trajectories corresponding to fluid motion at each of the excitation positions. The PWV can be reliably calculated by curve-fitting these trajectories to a model. In vitro studies using compliant tubes demonstrate no significant difference between results obtained using this method and those directly obtained using pressure transducers. Compared to another MR method previously developed in our laboratory, the proposed method displays improved temporal resolution and enhanced ability to extract PWV from vessels exhibiting low peak flow velocity. Preliminary data suggest that this method is feasible for in vivo application and may provide a more accurate estimation of aortic wave velocity among subjects exhibiting low peak flow velocity, such as the elderly or those with impaired cardiac function.
Arterial stiffness and heart rate recovery (HRR) following exercise testing have emerged as varia... more Arterial stiffness and heart rate recovery (HRR) following exercise testing have emerged as variables holding significant prognostic value in a number of populations. The purpose of the present study is to examine the relationship between arterial stiffness and HRR in a group of apparently healthy subjects. Two hundred and nine apparently healthy subjects underwent maximal exercise testing. Heart rate at one and two minutes post exercise was subtracted from maximal heart rate during the exercise test to produce two measures of heart rate recovery. Aortic wave velocity, in meters per second, was obtained via a new magnetic resonance technique. Pearson Product Moment Correlation analysis revealed a significant correlation between aortic wave velocity and heart rate recovery. Stepwise linear regression analysis revealed that age, maximal aerobic capacity, heart rate recovery at one minute, and diastolic blood pressure were all significant predictors of aortic wave velocity (r = 0.63, r2 = 0.40, p < 0.001). The results of the present study indicate that heart rate recovery is significantly correlated with a measure of large artery stiffness and adds predictive value to other clinical variables. This analysis provides further evidence that assessment of heart rate recovery should be considered in subjects undergoing exercise testing in clinical practice.
We investigated the use of a BodyLoc immobilization and stereotactic localization device combined... more We investigated the use of a BodyLoc immobilization and stereotactic localization device combined with TomoTherapy megavoltage CT (MVCT) in lung stereotactic body radiotherapy (SBRT) to reduce set-up uncertainty and treatment time. Eight patients treated with 3-5 fractions of SBRT were retrospectively analyzed. A BodyLoc localizer was used in both CT simulation for localization and the initial patient treatment set-up. Patients were immobilized with a vacuum cushion on the back and a thermoplastic body cast on the anterior body. Pretreatment MVCT from the TomoTherapy unit was fused with the planning kilovoltage CT (KVCT) before each fraction of treatment to determine interfractional set-up error. The comparison of two MVCTs during a fraction of treatment resulted in the intrafractional uncertainty of the treatment. A total of 224 target isocenter shifts were analyzed to assess these inter- and intrafractional tumor motions. We found that for interfractional shifts, the mean set-up errors and standard deviations were -1.1 +/- 2.8 mm, -2.5 +/- 8.7 mm, and 4.1 +/- 2.6 mm, for lateral, longitudinal, and vertical variation, respectively; the mean setup rotational variation was -0.3 +/- 0.7 degrees; and the maximum motion was 13.5 mm in the longitudinal direction. For intrafractional shifts, the mean set-up errors and standard deviations were -0.1 +/- 0.7 mm, -0.3 +/- 2.0 mm, and 0.5 +/- 1.1 mm for the lateral, longitudinal, and vertical shifts, respectively; the mean rotational variation was 0.1 +/- 0.2 degrees; and the maximum motion was 3.8 mm in the longitudinal direction. There was no correlation among patient characteristics, set-up uncertainties, and isocenter shifts, and the interfractional set-up uncertainties were larger than the intrafractional isocenter shift. The results of this study suggested that image-guided stereotactic body radiotherapy using the BodyLoc immobilization system with TomoTherapy can improve treatment accuracy.
A one-dimensional time-of-flight MR sequence, having a total acquisition time of approximately 60... more A one-dimensional time-of-flight MR sequence, having a total acquisition time of approximately 60 ms, has been employed to determine flow-wave propagation velocities for pulsatile flow in compliant latex tubes. The results were compared with those of two independent methods and were found to be in good agreement. An extension of the same MR method was used to test the validity of the "water-hammer" relationship as a means to assess pulse pressure. Very good agreement was found with direct manometric determinations of pulse pressure.
C-reactive protein (CRP) has emerged as an important indicator of risk for cardiovascular disease... more C-reactive protein (CRP) has emerged as an important indicator of risk for cardiovascular disease. The impact of gender on the relationship between CRP and other cardiovascular risk factors, however, has not been thoroughly investigated. Ninety men and 75 women participated in this study. Age, resting systolic and diastolic blood pressure, resting heart rate, body mass index, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, and hs-CRP were ascertained. Maximal oxygen consumption was obtained via treadmill testing, and aortic stiffness was measured using magnetic resonance imaging. Log hs-CRP level was significantly higher in the female subjects compared with the males subjects (0.86 +/- 0.67 mg/L vs 0.63 +/- 0.44 mg/L, respectively; P = .003). In the male group, Pearson product moment correlation analysis showed that log hs-CRP was not significantly correlated (P > .10) with any of the other variables of interest. In the female group, however, log hs-CRP was significantly correlated (P < .05) with total cholesterol (r = 0.30), low-density lipoprotein (r = 0.27), tryglycerides (r = 0.51), and body mass index (r = 0.36). Linear regression analysis determined that triglycerides and body mass index explained 30% of the variability in log hs-CRP. These results indicate that the relationship between CRP and other cardiac risk factors is different between apparently healthy men and women. The prognostic characteristics of CRP and the impact of statin therapy on CRP may therefore differ between men and women. Future research should be directed toward resolving this issue.
The purpose of this study was to evaluate a portable tool for use by first responders in document... more The purpose of this study was to evaluate a portable tool for use by first responders in documenting triage of victims in a mass casualty incident (MCI) more effectively. The tool presented in this study allows first responders to gather patients vital signs, injuries, and triage status in a prompt and accurate way, and enables first responders to wirelessly communicate vital health information throughout the entire care continuum. The architecture infrastructure for the portable device is called Triage and Casualty Informatics Technology (TACIT) and can expedite triage, transport and treatment procedures within an MCI. TACIT was developed by integrating handheld devices, wireless networks, global positioning system (GPS), digital cameras, and bar code scanners with customized triage software. Two MCI initial field trials verified that the TACIT software, battery life, data accuracy, and wireless transmission met the emergency response system requirements. Initial field trials also demonstrated robustness of operation, reduced triage collection time and improved collection accuracy. The TACIT system could work as an efficient prehospital response tool and platform.
Mental practice using motor imagery of limb movement may facilitate motor recovery in persons who... more Mental practice using motor imagery of limb movement may facilitate motor recovery in persons who have experienced cerebrovascular accident (CVA). However, the lack of a feedback mechanism that can monitor the quality of the motor imagery affects patients' engagement and motivation to participate in the mental practice training program. This study investigates the effect of novel real-time motor imagery-associated cortical activity feedback on motor imagery-based mental practice training. Ten healthy volunteers were randomly assigned into intervention and control groups. Both groups participated in a five-visit motor imagery-based mental practice training program managed over a period of two months. The intervention group received mental practice training with real-time feedback of movement-associated cortical activity-beta band (16-28 Hz) event-related desynchronization (ERD) in electroencephalography (EEG), using a novel custom-made brain-computer interface (BCI) system. The c...
Evoked potentials (EPs) to noxious thermal stimulation of skin may provide information about inte... more Evoked potentials (EPs) to noxious thermal stimulation of skin may provide information about integrity of the nociceptive afferent system and thus small afferent fiber integrity. Here we describe subjective report, EPs and response times to noxious contact thermal and laser stimuli in the same subjects. Pain quality to both forms of stimulation was consistently reported as a brief pricking or stinging sensation (first pain), occasionally followed, after a silent period, by a diffuse burning sensation (second pain). EPs to laser generated heat pulses consisted of bi- or triphasic waveforms with a large positive wave at approximately 300 ms following arm stimulation and 360 ms following stimulation of the leg. EPs to contact heat pulses consisted of a single, scalp positive wave occurring approximately 830 ms following arm stimulation and 890 ms following leg stimulation. Both forms of noxious stimulation activated afferents with a conduction velocity consistent with that of A-delta f...
A high frequency scanning acoustic microscope (SAM) operating at 1-1.3 GHz was used to investigat... more A high frequency scanning acoustic microscope (SAM) operating at 1-1.3 GHz was used to investigate subsurface defects in diamond-like carbon (DLC) films that were 2-3 μm thick. Because the wavelength of the longitudinal wave in the film was comparable to the film thickness, the acoustical images obtained were near-field images. To interpret the features in the acoustical images, a multidisciplinary
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
This study aims to explore whether human intentions to move or cease to move right and left hands... more This study aims to explore whether human intentions to move or cease to move right and left hands can provide four spatiotemporal patterns in single-trial non-invasive EEG signals to achieve a two-dimensional cursor control. Subjects performed motor tasks by either physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored to support accurate computer pattern recognition. The performance was evaluated by both offline classification and online two-dimensional cursor control. Event-related desynchronization (ERD) and post-movement event-related synchronization (ERS) were observed on the contralateral hemisphere to the moving hand for both physical movement and motor imagery. The offline classification of four motor tasks provided 10-fold cross-validation accuracy as high as 88% for physical movement and 73% for motor imagery. Subjects participating in experiments with physical movement were able to complete the...
We evaluated evoked potentials (EPs) to noxious contact heat pulses delivered to hairy skin of he... more We evaluated evoked potentials (EPs) to noxious contact heat pulses delivered to hairy skin of healthy adults. Heat pulses from an adapting temperature of 34 degrees C to a target temperature of 52 degrees C, produced two scalp positive waves. The first peaked at 44 degrees to 45 degrees C (approximately 500 ms following stimulus onset), while the second peaked approximately 300 ms following the 52 degrees C heat pulse (approximately 1 s after stimulus onset). The first positive wave was absent from an adapting temperature of 39 degrees C, suggesting loss of synchronized activation of warm and/or low threshold mechanothermal afferents. The second EP was observed following stimulation from both adapting temperatures and was associated with subjective report of first pain. Latency difference of the pain EP from arm and leg were consistent with conduction in Adelta nociceptive afferents (approximately 10/ms). EPs to painful contact thermal stimuli may be of value in the evaluation of small fiber peripheral neuropathies and assessment of altered pain states.
The purpose of this study was to evaluate a portable tool for use by first responders in document... more The purpose of this study was to evaluate a portable tool for use by first responders in documenting triage of victims in a mass casualty incident (MCI) more effectively. The tool presented in this study allows first responders to gather patients vital signs, injuries, and triage status in a prompt and accurate way, and enables first responders to wirelessly communicate vital health information throughout the entire care continuum. The architecture infrastructure for the portable device is called Triage and Casualty Informatics Technology (TACIT) and can expedite triage, transport and treatment procedures within an MCI. TACIT was developed by integrating handheld devices, wireless networks, global positioning system (GPS), digital cameras, and bar code scanners with customized triage software. Two MCI initial field trials verified that the TACIT software, battery life, data accuracy, and wireless transmission met the emergency response system requirements. Initial field trials also demonstrated robustness of operation, reduced triage collection time and improved collection accuracy. The TACIT system could work as an efficient prehospital response tool and platform.
Journal of Biomechanical Engineering-transactions of The Asme, 1988
A time-of-flight MRI velocity measurement technique is evaluated against corresponding LDV measur... more A time-of-flight MRI velocity measurement technique is evaluated against corresponding LDV measurements in a constriction tube model over a range of physiologic flow conditions. Results from this study show that MR displacement images can: 1) be obtained within both laminar and turbulent jets (maximum stenotic Re approximately equal to 4,200), 2) measure mean jet velocities up to 172 cm/s, and, 3) detect low forward and reverse stenosis (0 less than or equal to L/D less than or equal to 2). Regions between the jet termination point and re-establishment of laminar flow (Re greater than or equal to 1500, greater than or equal to 1000, and greater than or equal to 110 downstream of 40, 60, and 80 percent stenosis, respectively) cannot presently be detected by this technique.
A 1D MR sequence has been developed for determining aortic flow wave velocity (WV), a metric of a... more A 1D MR sequence has been developed for determining aortic flow wave velocity (WV), a metric of arterial compliance, within a single cardiac cycle. Studies were carried out on the thoracic aortas of 10 normal volunteers. Correlative WV data were also acquired from each subject using a conventional phase-veloc- ity 2D mapping technique. Aortic WV in this cohort was found
A MR method is presented for measuring pulse wave velocity (PWV) and its application to assessing... more A MR method is presented for measuring pulse wave velocity (PWV) and its application to assessing stiffness in the human thoracic aorta. This one-dimensional (1D) flow displacement method applies a single RF comb excitation to the vessel, followed by an oscillating frequency encoding gradient, each oscillation providing a 1D projection of the vessel, enabling one to track fluid motion. The currently implemented sequence excites nine slices within a 20-cm length of vessel and has a temporal resolution of 2.03 msec and a total acquisition time of 140 msec. Offline-reconstructed position-versus-time plots show curvilinear flow displacement trajectories corresponding to fluid motion at each of the excitation positions. The PWV can be reliably calculated by curve-fitting these trajectories to a model. In vitro studies using compliant tubes demonstrate no significant difference between results obtained using this method and those directly obtained using pressure transducers. Compared to another MR method previously developed in our laboratory, the proposed method displays improved temporal resolution and enhanced ability to extract PWV from vessels exhibiting low peak flow velocity. Preliminary data suggest that this method is feasible for in vivo application and may provide a more accurate estimation of aortic wave velocity among subjects exhibiting low peak flow velocity, such as the elderly or those with impaired cardiac function.
Arterial stiffness and heart rate recovery (HRR) following exercise testing have emerged as varia... more Arterial stiffness and heart rate recovery (HRR) following exercise testing have emerged as variables holding significant prognostic value in a number of populations. The purpose of the present study is to examine the relationship between arterial stiffness and HRR in a group of apparently healthy subjects. Two hundred and nine apparently healthy subjects underwent maximal exercise testing. Heart rate at one and two minutes post exercise was subtracted from maximal heart rate during the exercise test to produce two measures of heart rate recovery. Aortic wave velocity, in meters per second, was obtained via a new magnetic resonance technique. Pearson Product Moment Correlation analysis revealed a significant correlation between aortic wave velocity and heart rate recovery. Stepwise linear regression analysis revealed that age, maximal aerobic capacity, heart rate recovery at one minute, and diastolic blood pressure were all significant predictors of aortic wave velocity (r = 0.63, r2 = 0.40, p < 0.001). The results of the present study indicate that heart rate recovery is significantly correlated with a measure of large artery stiffness and adds predictive value to other clinical variables. This analysis provides further evidence that assessment of heart rate recovery should be considered in subjects undergoing exercise testing in clinical practice.
We investigated the use of a BodyLoc immobilization and stereotactic localization device combined... more We investigated the use of a BodyLoc immobilization and stereotactic localization device combined with TomoTherapy megavoltage CT (MVCT) in lung stereotactic body radiotherapy (SBRT) to reduce set-up uncertainty and treatment time. Eight patients treated with 3-5 fractions of SBRT were retrospectively analyzed. A BodyLoc localizer was used in both CT simulation for localization and the initial patient treatment set-up. Patients were immobilized with a vacuum cushion on the back and a thermoplastic body cast on the anterior body. Pretreatment MVCT from the TomoTherapy unit was fused with the planning kilovoltage CT (KVCT) before each fraction of treatment to determine interfractional set-up error. The comparison of two MVCTs during a fraction of treatment resulted in the intrafractional uncertainty of the treatment. A total of 224 target isocenter shifts were analyzed to assess these inter- and intrafractional tumor motions. We found that for interfractional shifts, the mean set-up errors and standard deviations were -1.1 +/- 2.8 mm, -2.5 +/- 8.7 mm, and 4.1 +/- 2.6 mm, for lateral, longitudinal, and vertical variation, respectively; the mean setup rotational variation was -0.3 +/- 0.7 degrees; and the maximum motion was 13.5 mm in the longitudinal direction. For intrafractional shifts, the mean set-up errors and standard deviations were -0.1 +/- 0.7 mm, -0.3 +/- 2.0 mm, and 0.5 +/- 1.1 mm for the lateral, longitudinal, and vertical shifts, respectively; the mean rotational variation was 0.1 +/- 0.2 degrees; and the maximum motion was 3.8 mm in the longitudinal direction. There was no correlation among patient characteristics, set-up uncertainties, and isocenter shifts, and the interfractional set-up uncertainties were larger than the intrafractional isocenter shift. The results of this study suggested that image-guided stereotactic body radiotherapy using the BodyLoc immobilization system with TomoTherapy can improve treatment accuracy.
A one-dimensional time-of-flight MR sequence, having a total acquisition time of approximately 60... more A one-dimensional time-of-flight MR sequence, having a total acquisition time of approximately 60 ms, has been employed to determine flow-wave propagation velocities for pulsatile flow in compliant latex tubes. The results were compared with those of two independent methods and were found to be in good agreement. An extension of the same MR method was used to test the validity of the "water-hammer" relationship as a means to assess pulse pressure. Very good agreement was found with direct manometric determinations of pulse pressure.
C-reactive protein (CRP) has emerged as an important indicator of risk for cardiovascular disease... more C-reactive protein (CRP) has emerged as an important indicator of risk for cardiovascular disease. The impact of gender on the relationship between CRP and other cardiovascular risk factors, however, has not been thoroughly investigated. Ninety men and 75 women participated in this study. Age, resting systolic and diastolic blood pressure, resting heart rate, body mass index, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, and hs-CRP were ascertained. Maximal oxygen consumption was obtained via treadmill testing, and aortic stiffness was measured using magnetic resonance imaging. Log hs-CRP level was significantly higher in the female subjects compared with the males subjects (0.86 +/- 0.67 mg/L vs 0.63 +/- 0.44 mg/L, respectively; P = .003). In the male group, Pearson product moment correlation analysis showed that log hs-CRP was not significantly correlated (P > .10) with any of the other variables of interest. In the female group, however, log hs-CRP was significantly correlated (P < .05) with total cholesterol (r = 0.30), low-density lipoprotein (r = 0.27), tryglycerides (r = 0.51), and body mass index (r = 0.36). Linear regression analysis determined that triglycerides and body mass index explained 30% of the variability in log hs-CRP. These results indicate that the relationship between CRP and other cardiac risk factors is different between apparently healthy men and women. The prognostic characteristics of CRP and the impact of statin therapy on CRP may therefore differ between men and women. Future research should be directed toward resolving this issue.
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