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Sample records for contrast material hemodynamic

  1. Contrast Materials

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Contrast Materials What are contrast materials and how do they ... material? Pregnancy and contrast materials What are contrast materials and how do they work? Contrast materials, also ...

  2. Hemodynamic changes in patients with extracorporeal membrane oxygenation (ECMO) demonstrated by contrast-enhanced CT examinations - implications for image acquisition technique.

    Science.gov (United States)

    Lambert, Lukas; Grus, Tomas; Balik, Martin; Fichtl, Jaromir; Kavan, Jan; Belohlavek, Jan

    2016-10-30

    Extracorporeal membrane oxygenation (ECMO) is an established tool for respiratory and circulatory support. In computed tomography, altered hemodynamics in ECMO patients requires special considerations and handling in contrast injection and its timing. In this article, we demonstrate changes in hemodynamics in ECMO patients captured on contrast-enhanced CT examinations and pitfalls in strategies for contrast injection in relation to the ECMO flow, cardiac function and the placement of ECMO cannulas. Contrast-enhanced CT of patients with ECMO requires prior knowledge of the ECMO cannulas, central venous lines, changes of hemodynamics induced by low cardiac output and the influence of adjustment of ECMO on blood flow in order to optimize injection of the contrast material and timing of the scan. Special considerations include temporary reduction of the ECMO flow, selection of the injection site and increasing volume or flow rate of the contrast material.

  3. Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

    Science.gov (United States)

    Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

    2016-09-01

    Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

  4. Hemodynamic Measurement Using Four-Dimensional Phase-Contrast MRI: Quantification of Hemodynamic Parameters and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Hojin [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Guk Bae [Asan Institute of Life Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kweon, Jihoon [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Young-Hak [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Deok Hee; Yang, Dong Hyun [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kim, Namkug [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of)

    2016-11-01

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  5. Hemodynamic measurement using four-dimensional phase-contrast MRI: Quantification of hemodynamic parameters and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ho Jin; Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Guk Bae; Kweon, Ji Hoon; Kim, Young Hak; Lee, Deok Hee; Yang, Dong Hyun; KIm, Nam Kug [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-07-15

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  6. Hemodynamic analysis of intracranial aneurysms using phase-contrast magnetic resonance imaging and computational fluid dynamics

    Science.gov (United States)

    Zhao, Xuemei; Li, Rui; Chen, Yu; Sia, Sheau Fung; Li, Donghai; Zhang, Yu; Liu, Aihua

    2017-03-01

    Additional hemodynamic parameters are highly desirable in the clinical management of intracranial aneurysm rupture as static medical images cannot demonstrate the blood flow within aneurysms. There are two ways of obtaining the hemodynamic information—by phase-contrast magnetic resonance imaging (PCMRI) and computational fluid dynamics (CFD). In this paper, we compared PCMRI and CFD in the analysis of a stable patient's specific aneurysm. The results showed that PCMRI and CFD are in good agreement with each other. An additional CFD study of two stable and two ruptured aneurysms revealed that ruptured aneurysms have a higher statistical average blood velocity, wall shear stress, and oscillatory shear index (OSI) within the aneurysm sac compared to those of stable aneurysms. Furthermore, for ruptured aneurysms, the OSI divides the positive and negative wall shear stress divergence at the aneurysm sac.

  7. Non-invasive prediction of hemodynamically significant coronary artery stenoses by contrast density difference in coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Hell, Michaela M., E-mail: michaela.hell@uk-erlangen.de [Department of Cardiology, University of Erlangen (Germany); Dey, Damini [Department of Biomedical Sciences, Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Taper Building, Room A238, 8700 Beverly Boulevard, Los Angeles, CA 90048 (United States); Marwan, Mohamed; Achenbach, Stephan; Schmid, Jasmin; Schuhbaeck, Annika [Department of Cardiology, University of Erlangen (Germany)

    2015-08-15

    Highlights: • Overestimation of coronary lesions by coronary computed tomography angiography and subsequent unnecessary invasive coronary angiography and revascularization is a concern. • Differences in plaque characteristics and contrast density difference between hemodynamically significant and non-significant stenoses, as defined by invasive fractional flow reserve, were assessed. • At a threshold of ≥24%, contrast density difference predicted hemodynamically significant lesions with a specificity of 75%, sensitivity of 33%, PPV of 35% and NPV of 73%. • The determination of contrast density difference required less time than transluminal attenuation gradient measurement. - Abstract: Objectives: Coronary computed tomography angiography (CTA) allows the detection of obstructive coronary artery disease. However, its ability to predict the hemodynamic significance of stenoses is limited. We assessed differences in plaque characteristics and contrast density difference between hemodynamically significant and non-significant stenoses, as defined by invasive fractional flow reserve (FFR). Methods: Lesion characteristics of 59 consecutive patients (72 lesions) in whom invasive FFR was performed in at least one coronary artery with moderate to high-grade stenoses in coronary CTA were evaluated by two experienced readers. Coronary CTA data sets were acquired on a second-generation dual-source CT scanner using retrospectively ECG-gated spiral acquisition or prospectively ECG-triggered axial acquisition mode. Plaque volume and composition (non-calcified, calcified), remodeling index as well as contrast density difference (defined as the percentage decline in luminal CT attenuation/cross-sectional area over the lesion) were assessed using a semi-automatic software tool (Autoplaq). Additionally, the transluminal attenuation gradient (defined as the linear regression coefficient between intraluminal CT attenuation and length from the ostium) was determined

  8. Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease.

    Science.gov (United States)

    Fernandes, Sheila Marques; Martins, Daniel Malisani; da Fonseca, Cassiane Dezoti; Watanabe, Mirian; Vattimo, Maria de Fátima Fernandes

    2016-01-01

    Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI.

  9. Hemodynamic analysis of bladder tumors using T{sub 1}-dynamic contrast-enhanced fast spin-echo MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Yuki, E-mail: yukikanazawa@me.com [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Department of Radiology, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto (Japan); Miyati, Tosiaki [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Sato, Osamu [Department of Radiology, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto (Japan)

    2012-08-15

    Objectives: To evaluate the hemodynamics of bladder tumors, we developed a method to calculate change in R{sub 1} value ({Delta}R{sub 1}) from T{sub 1}-dynamic contrast-enhanced fast spin-echo magnetic resonance imaging (T{sub 1}DCE-FSE-MRI). Materials and methods: On a 1.5-T MR system, T{sub 1}DCE-FSE-MRI was performed. This study was applied to 12 patients with urinary bladder tumor, i.e. urothelial carcinoma. We compared {Delta}R{sub 1}-time and {Delta}SI-time between a peak in the {Delta}R{sub 1}-time and {Delta}SI-time curve occurred during the first pass within 60 s. Next, we assessed the slope of increase for 180 s after CA injection (Slope{sub 0-180}). Results: The mean slope of the first pass was significantly higher for bladder tumors on both the {Delta}R{sub 1}-time and the {Delta}SI-time curve compared with normal bladder walls. Moreover, a significant difference was apparent between bladder tumors and normal bladder walls on the mean Slope{sub 0-180} in the {Delta}R{sub 1}-time curve. However, no significant difference in the mean Slope{sub 0-180} was observed on the {Delta}SI-time curve between bladder tumors and normal bladder walls. Conclusion: T{sub 1}DCE-FSE-MRI offers three advantages: quantitative analysis; high-quality (i.e., artifact-free) images; and high temporal resolution even for SE images. Use of {Delta}R{sub 1} analysis with T{sub 1}DCE-FSE-MRI allows more detailed information on the hemodynamics of bladder tumors to be obtained and assists in differentiation between bladder tumors and the normal bladder wall.

  10. Contrasting hemodynamic mechanisms of losartan- vs. atenolol-based antihypertensive treatment

    DEFF Research Database (Denmark)

    Greve, Anders M; Olsen, Michael H; Bella, Jonathan N

    2012-01-01

    Pharmaceutical differences in central hemodynamics might influence cardiac response to antihypertensive treatment despite similar lowering of brachial blood pressure (BP).......Pharmaceutical differences in central hemodynamics might influence cardiac response to antihypertensive treatment despite similar lowering of brachial blood pressure (BP)....

  11. The hemodynamics in intracranial aneurysm ruptured region with active contrast leakage during computed tomography angiography

    Science.gov (United States)

    Li, Ming-Lung; Wang, Yi-Chou; Liou, Tong-Miin; Lin, Chao-An

    2014-10-01

    Precise locations of rupture region under contrast agent leakage of five ruptured cerebral artery aneurysms during computed tomography angiography, which is to our knowledge for the first time, were successfully identified among 101 patients. These, together with numerical simulations based on the reconstructed aneurysmal models, were used to analyze hemodynamic parameters of aneurysms under different cardiac cyclic flow rates. For side wall type aneurysms, different inlet flow rates have mild influences on the shear stresses distributions. On the other hand, for branch type aneurysms, the predicted wall shear stress (WSS) correlates strongly with the increase of inlet vessel velocity. The mean and time averaged WSSes at rupture regions are found to be lower than those over the surface of the aneurysms. Also, the levels of the oscillatory shear index (OSI) are higher than the reported threshold value, supporting the assertion that high OSI correlates with rupture of the aneurysm. However, the present results also indicate that OSI level at the rupture region is relatively lower.

  12. Hemodynamic evaluation with TURBO BRISK--a rapid phase contrast angiography technique.

    Science.gov (United States)

    Anayiotos, A S; Kortright, E; Doyle, M; Walsh, E G; Fuisz, A R; Pohost, G M

    2000-01-01

    Hemodynamic imaging by phase contrast angiography was significantly accelerated by selective interpolation and segmentation in k-space using TURBO BRISK. The method was tested in vitro on three independent flowfields, representative of human blood rheology: a straight tube simulating the descending aorta, a curved tube simulating the aortic arch and a two-chamber orifice flow model simulating valvular regurgitation. The results were compared to data obtained by Laser Doppler Velocimetry (LDV) and showed good agreement. For the straight tube, the flow velocity obtained by five TURBO BRISK methods with increasing segmentation factors and corresponding time savings showed good agreement with LDV. For the curved tube, the velocity showed good general agreement with some differences in the decelerating part of the cycle, and in the low-velocity secondary flow structures. The orifice flow evaluation, the most time consuming case, was performed by the control volume method. It showed good agreement with actual flows through the orifice. Data acquisitions for TURBO-4 BRISK could be performed in 20s for each velocity component. The method shows promise for breath-hold acquisitions in clinical applications, including calculation of blood flow volumes through diseased arteries, measurement of blood backflow volumes through dysfunctional heart valves to time valve replacement operations, and evaluation of arterial wall shear stress, an important factor in the genesis of atherosclerosis.

  13. Reconstruction of cerebral hemodynamics with dynamic contrast-enhanced time-resolved near-infrared measurements before and during ischemia

    Science.gov (United States)

    Elliott, Jonathan T.; Diop, Mamadou; Morrison, Laura B.; Lee, Ting-Yim; St. Lawrence, Keith

    2013-03-01

    We present a dynamic contrast-enhanced near-infrared (DCE-NIR) technique that is capable of non-invasive quantification of cerebral hemodynamics in adults. The challenge of removing extracerebral contamination is overcome through the use of multi-distance time-resolved DCE-NIR combined with the kinetic deconvolution optical reconstruction (KDOR) analytical method. As proof-of-principle, cerebral blood flow, cerebral blood volume and mean transit time recovered with DCE-NIR are compared with CT perfusion values in an adult pig during normocapnia, hypocapnia, and ischemia. Measurements of blood flow acquired with DCE-NIR were compared against concomitant measurements using CT Perfusion.

  14. Addition of local anesthetics to contrast media. Pt. 1. Effects on patient discomfort and hemodynamics in aortofemoral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, P.; Almen, T.; Golman, K.; Jonsson, K.; Nyman, U.

    Effects of equiosmolar solutions (osmolality 1.35 mol/kg) of the ratio 1.5 contrast medium metrizoate (250 mg I/ml) containing either the local anesthetic mepivacaine or saline were evaluated on subjective discomfort, aortic blood pressure and heart rate in 17 patients referred for aortofemoral angiography due to intermittent claudication. Each patient was injected with 30 ml (15 ml/s) of each solution in random double-blind order. Each patient was then injected with 45 ml (12 ml/s) of the raio 3 medium ioxaglate (320 mg I/ml, osmolality 0.58 ml/kg). Ioxaglate caused significantly less total discomfort, pain, heat, vocal reaction, involuntary movements and hemodynamic effects than mitrizoate-mepivacaine and metrizoate-saline. The effects of the two metrizoate solutions did not differ significantly. Previous contradictory reports on the effects of anesthetics in contrast media were reviewed with regard to experimental design, different osmolality of the test and control solutions, premedication, and pH dependence of local anesthetics. Ratio 3 media are recommended because they produce a more reliable relief of patient discomfort and fewer hemodynamic changes than the addition of local anesthetics to ratio 1.5 media.

  15. Influence of Spatial Resolution in Three-dimensional Cine Phase Contrast Magnetic Resonance Imaging on the Accuracy of Hemodynamic Analysis.

    Science.gov (United States)

    Fukuyama, Atsushi; Isoda, Haruo; Morita, Kento; Mori, Marika; Watanabe, Tomoya; Ishiguro, Kenta; Komori, Yoshiaki; Kosugi, Takafumi

    2017-10-10

    We aim to elucidate the effect of spatial resolution of three-dimensional cine phase contrast magnetic resonance (3D cine PC MR) imaging on the accuracy of the blood flow analysis, and examine the optimal setting for spatial resolution using flow phantoms. The flow phantom has five types of acrylic pipes that represent human blood vessels (inner diameters: 15, 12, 9, 6, and 3 mm). The pipes were fixed with 1% agarose containing 0.025 mol/L gadolinium contrast agent. A blood-mimicking fluid with human blood property values was circulated through the pipes at a steady flow. Magnetic resonance (MR) images (three-directional phase images with speed information and magnitude images for information of shape) were acquired using the 3-Tesla MR system and receiving coil. Temporal changes in spatially-averaged velocity and maximum velocity were calculated using hemodynamic analysis software. We calculated the error rates of the flow velocities based on the volume flow rates measured with a flowmeter and examined measurement accuracy. When the acrylic pipe was the size of the thoracicoabdominal or cervical artery and the ratio of pixel size for the pipe was set at 30% or lower, spatially-averaged velocity measurements were highly accurate. When the pixel size ratio was set at 10% or lower, maximum velocity could be measured with high accuracy. It was difficult to accurately measure maximum velocity of the 3-mm pipe, which was the size of an intracranial major artery, but the error for spatially-averaged velocity was 20% or less. Flow velocity measurement accuracy of 3D cine PC MR imaging for pipes with inner sizes equivalent to vessels in the cervical and thoracicoabdominal arteries is good. The flow velocity accuracy for the pipe with a 3-mm-diameter that is equivalent to major intracranial arteries is poor for maximum velocity, but it is relatively good for spatially-averaged velocity.

  16. Wide-area mapping of resting state hemodynamic correlations at microvascular resolution with multi-contrast optical imaging (Conference Presentation)

    Science.gov (United States)

    Senarathna, Janaka; Hadjiabadi, Darian; Gil, Stacy; Thakor, Nitish V.; Pathak, Arvind P.

    2017-02-01

    Different brain regions exhibit complex information processing even at rest. Therefore, assessing temporal correlations between regions permits task-free visualization of their `resting state connectivity'. Although functional MRI (fMRI) is widely used for mapping resting state connectivity in the human brain, it is not well suited for `microvascular scale' imaging in rodents because of its limited spatial resolution. Moreover, co-registered cerebral blood flow (CBF) and total hemoglobin (HbT) data are often unavailable in conventional fMRI experiments. Therefore, we built a customized system that combines laser speckle contrast imaging (LSCI), intrinsic optical signal (IOS) imaging and fluorescence imaging (FI) to generate multi-contrast functional connectivity maps at a spatial resolution of 10 μm. This system comprised of three illumination sources: a 632 nm HeNe laser (for LSCI), a 570 nm ± 5 nm filtered white light source (for IOS), and a 473 nm blue laser (for FI), as well as a sensitive CCD camera operating at 10 frames per second for image acquisition. The acquired data enabled visualization of changes in resting state neurophysiology at microvascular spatial scales. Moreover, concurrent mapping of CBF and HbT-based temporal correlations enabled in vivo mapping of how resting brain regions were linked in terms of their hemodynamics. Additionally, we complemented this approach by exploiting the transit times of a fluorescent tracer (Dextran-FITC) to distinguish arterial from venous perfusion. Overall, we demonstrated the feasibility of wide area mapping of resting state connectivity at microvascular resolution and created a new toolbox for interrogating neurovascular function.

  17. The Effect of Contrast Material on Radiation Dose at CT: Part I. Incorporation of Contrast Material Dynamics in Anthropomorphic Phantoms.

    Science.gov (United States)

    Sahbaee, Pooyan; Segars, W Paul; Marin, Daniele; Nelson, Rendon C; Samei, Ehsan

    2017-06-01

    Purpose To develop a method to incorporate the propagation of contrast material into computational anthropomorphic phantoms for estimation of organ dose at computed tomography (CT). Materials and Methods A patient-specific physiologically based pharmacokinetic (PBPK) model of the human cardiovascular system was incorporated into 58 extended cardiac-torso (XCAT) patient phantoms. The PBPK model comprised compartmental models of vessels and organs unique to each XCAT model. For typical injection protocols, the dynamics of the contrast material in the body were described according to a series of patient-specific iodine mass-balance differential equations, the solutions to which provided the contrast material concentration time curves for each compartment. Each organ was assigned to a corresponding time-varying iodinated contrast agent to create the contrast material-enhanced five-dimensional XCAT models, in which the fifth dimension represents the dynamics of contrast material. To validate the accuracy of the models, simulated aortic and hepatic contrast-enhancement results throughout the models were compared with previously published clinical data by using the percentage of discrepancy in the mean, time to 90% peak, peak value, and slope of enhancement in a paired t test at the 95% significance level. Results The PBPK model allowed effective prediction of the time-varying concentration curves of various contrast material administrations in each organ for different patient models. The contrast-enhancement results were in agreement with results of previously published clinical data, with mean percentage, time to 90% peak, peak value, and slope of less than 10% (P > .74), 4%, 7%, and 14% for uniphasic and 12% (P > .56), 4%, 12%, and 14% for biphasic injection protocols, respectively. The exception was hepatic enhancement results calculated for a uniphasic injection protocol for which the discrepancy was less than 25%. Conclusion A technique to model the propagation of

  18. Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI

    Science.gov (United States)

    Ambarki, Khalid; Eklund, Anders; Malm, Jan; Mulder, Edwin; Gerlach, Darius; Rittweger, Jörn

    2016-01-01

    Alterations in cerebral hemodynamics in microgravity are hypothesized to occur during spaceflight and could be linked to the Visual Impairment and Intracranial Pressure syndrome. Head-down tilt (HDT) is frequently used as a ground-based analog to simulate cephalad fluid shifts in microgravity; however, its effects on cerebral hemodynamics have not been well studied with MRI techniques. Here, we evaluate the effects of 1) various HDT angles on cerebral arterial and venous hemodynamics; and 2) exposure to 1% CO2 during an intermediate HDT angle (−12°) as an additional space-related environmental factor. Blood flow, cross-sectional area (CSA), and blood flow velocity were measured with phase-contrast MRI in the internal jugular veins, as well as the vertebral and internal carotid arteries. Nine healthy male subjects were measured at baseline (supine, 0°) and after 4.5 h of HDT at −6°, −12° (with and without 1% CO2), and −18°. We found a decrease in total arterial blood flow from baseline during all angles of HDT. On the venous side, CSA increased with HDT, and outflow decreased during −12° HDT (P = 0.039). Moreover, the addition of 1% CO2 to −12° HDT caused an increase in total arterial blood flow (P = 0.016) and jugular venous outflow (P < 0.001) compared with −12° HDT with ambient atmosphere. Overall, the results indicate decreased cerebral blood flow during HDT, which may have implications for microgravity-induced cerebral hemodynamic changes. PMID:27013606

  19. Assessment of contrast-enhanced ultrasonography of the hepatic vein for detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs.

    Science.gov (United States)

    Morishita, Keitaro; Hiramoto, Akira; Michishita, Asuka; Takagi, Satoshi; Hoshino, Yuki; Itami, Takaharu; Lim, Sue Yee; Osuga, Tatsuyuki; Nakamura, Sayuri; Ochiai, Kenji; Nakamura, Kensuke; Ohta, Hiroshi; Yamasaki, Masahiro; Takiguchi, Mitsuyoshi

    2017-04-01

    OBJECTIVE To assess the use of contrast-enhanced ultrasonography (CEUS) of the hepatic vein for the detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs. ANIMALS 6 healthy Beagles. PROCEDURES A prospective study was conducted. A catheter was surgically placed in the portal vein of each dog. Hypertension was induced by intraportal injection of microspheres (10 to 15 mg/kg) at 5-day intervals via the catheter. Microsphere injections were continued until multiple acquired portosystemic shunts were created. Portal vein pressure (PVP) was measured through the catheter. Contrast-enhanced ultrasonography was performed before and after establishment of hypertension. Time-intensity curves were generated from the region of interest in the hepatic vein. Perfusion variables measured for statistical analysis were hepatic vein arrival time, time to peak, time to peak phase (TTPP), and washout ratio. The correlation between CEUS variables and PVP was assessed by use of simple regression analysis. RESULTS Time to peak and TTPP were significantly less after induction of portal hypertension. Simple regression analysis revealed a significant negative correlation between TTPP and PVP. CONCLUSIONS AND CLINICAL RELEVANCE CEUS was useful for detecting hemodynamic changes associated with experimentally induced portal hypertension in dogs, which was characterized by a rapid increase in the intensity of the hepatic vein. Furthermore, TTPP, a time-dependent variable, provided useful complementary information for predicting portal hypertension. IMPACT FOR HUMAN MEDICINE Because the method described here induced presinusoidal portal hypertension, these results can be applied to idiopathic portal hypertension in humans.

  20. In vivo hemodynamic analysis of intracranial aneurysms obtained by magnetic resonance fluid dynamics (MRFD) based on time-resolved three-dimensional phase-contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Isoda, Haruo; Takeda, Hiroyasu; Yamashita, Shuhei; Takehara, Yasuo; Sakahara, Harumi [Hamamatsu University School of Medicine, Department of Radiology, Hamamatsu, Shizuoka (Japan); Ohkura, Yasuhide; Kosugi, Takashi [Renaissance of Technology Corporation, Hamamatsu, Shizuoka (Japan); Hirano, Masaya [GE Healthcare Japan, Tokyo (Japan); Hiramatsu, Hisaya; Namba, Hiroki [Hamamatsu University School of Medicine, Department of Neurosurgery, Hamamatsu, Shizuoka (Japan); Alley, Marcus T.; Bammer, Roland; Pelc, Norbert J. [Stanford University School of Medicine, Department of Radiology, Radiological Sciences Laboratory, Stanford, CA (United States)

    2010-10-15

    Hemodynamics is thought to play a very important role in the initiation, growth, and rupture of intracranial aneurysms. The purpose of our study was to perform in vivo hemodynamic analysis of unruptured intracranial aneurysms of magnetic resonance fluid dynamics using time-resolved three-dimensional phase-contrast MRI (4D-Flow) at 1.5 T and to analyze relationships between hemodynamics and wall shear stress (WSS) and oscillatory shear index (OSI). This study included nine subjects with 14 unruptured aneurysms. 4D-Flow was performed by a 1.5-T magnetic resonance scanner with a head coil. We calculated in vivo streamlines, WSS, and OSI of intracranial aneurysms based on 4D-Flow with our software. We evaluated the number of spiral flows in the aneurysms and compared the differences in WSS or OSI between the vessel and aneurysm and between whole aneurysm and the apex of the spiral flow. 3D streamlines, WSS, and OSI distribution maps in arbitrary direction during the cardiac phase were obtained for all intracranial aneurysms. Twelve aneurysms had one spiral flow each, and two aneurysms had two spiral flows each. The WSS was lower and the OSI was higher in the aneurysm compared to the vessel. The apex of the spiral flow had a lower WSS and higher OSI relative to the whole aneurysm. Each intracranial aneurysm in this study had at least one spiral flow. The WSS was lower and OSI was higher at the apex of the spiral flow than the whole aneurysmal wall. (orig.)

  1. Hemodynamic and morphologic changes of peripheral hepatic vasculature in cirrhotic liver disease: A preliminary study using contrast-enhanced coded phase inversion harmonic ultrasonography

    Institute of Scientific and Technical Information of China (English)

    Rong-Qin Zheng; Bo Zhang; Masatoshi Kudo; Yasuhiro Sakaguchi

    2005-01-01

    AIM: To provide the useful information for the diagnosis of liver cirrhosis by observing the morphology of peripheral hepatic vessels and the hemodynamics of microbubble arrival time in these vessels.METHODS: Twenty-one subjects including 5 normal volunteers and 16 patients (liver cirrhosis, n=10;chronic hepatitis, n=6) were studied by contrast-enhanced coded phase inversion harmonic sonography (GE LOGIQ9 series) using a 6-8 MHz convex-arrayed wide-band transducer. The images of peripheral hepatic artery,portal and hepatic vein were observed in real-time for about 2 min after intravenous injection of Levovist. The time when microbubbles appeared in the peripheral vessels (microbubble arrival time) was also recorded. The morphologic changes of peripheral hepatic vasculature were classified as marked, slight, and no changes based on the regularity in caliber, course, ramification, and the delineation of vessels compared to normal subjects.RESULTS: The microbubble arrival time at peripheral artery, portal, and hepatic vein was shorter in cirrhotic patients than in chronic hepatitis patients and normal subjects. The marked, slight and no morphologic changes of peripheral hepatic vasculature found in 5 (5/6,83.3%), 1 (1/6, 16.7% ), and 0 (0/6, 0%) liver cirrhosis patients, respectively, and in 1 (1/10, 10%), 6 (6/10,60%), and 3 (3/10, 30%) chronic hepatitis patients,respectively. There was a significant difference between the two groups (P<0.001).CONCLUSION: Evaluation of the hemodynamics and morphology of peripheral hepatic vasculature by contrast-enhanced coded pulse inversion harmonic sonography can provide useful information for the diagnosis of liver cirrhosis.

  2. Hybrid material as contrast agent in magnetic resonance images

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2015-01-01

    [EN] The invention relates to a contrast agent of magnetic resonance based on a hybrid material formed by an organo-metallic core derived from Prussian blue and a silica cover, and optionally, molecules of a poly(ethylene glycol), a fluorescent agent, a radio nucleus and/or a substance that directs to specific receptors, cells or tissues, joined by covalent bonding to the surface of the inorganic cover.

  3. Hybrid material as contrast agent in magnetic resonance images

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2015-01-01

    [EN] The invention relates to a contrast agent of magnetic resonance based on a hybrid material formed by an organo-metallic core derived from Prussian blue and a silica cover, and optionally, molecules of a poly(ethylene glycol), a fluorescent agent, a radio nucleus and/or a substance that directs to specific receptors, cells or tissues, joined by covalent bonding to the surface of the inorganic cover.

  4. Contrasting cardiopulmonary responses to incremental exercise in patients with schistosomiasis-associated and idiopathic pulmonary arterial hypertension with similar resting hemodynamic impairment.

    Directory of Open Access Journals (Sweden)

    Fabricio Martins Valois

    Full Text Available It has been reported that schistosomiasis-associated PAH (Sch-PAH has a more benign clinical course compared with idiopathic PAH (IPAH. We therefore hypothesized that Sch-PAH subjects would present with less impaired cardiopulmonary and metabolic responses to exercise than IPAH patients, even with similar resting pulmonary hemodynamic abnormalities. The aim of this study was to contrast physiologic responses to incremental exercise on cycle ergometer between subjects with Sch-PAH and IPAH. We performed incremental cardiopulmonary exercise tests (CPET in subjects newly diagnosed with IPAH (n = 9 and Sch-PAH (n = 8, within 1 month of the hemodynamic study and before the initiation of specific therapy for PAH. There were no significant between-group differences in cardiac index, pulmonary vascular resistance or mean pulmonary artery pressure. However, mean peak oxygen uptake (VO2 was greater in Sch-PAH than IPAH patients (75.5±21.4 vs 54.1±16.1% predicted, p = 0.016, as well as the ratio of increase in VO2 to work rate (8.2±1.0 vs 6.8±1.8 mL/min/W, p = 0.03. Additionally, the slope of the ventilatory response as a function of CO2 output was lower in Sch-PAH (40.3±3.9 vs 55.6±19.8; p = 0.04, and the heart rate response for a given change in VO2 was also diminished in Sch-PAH compared to IPAH (80.1±20.6 vs 123.0±39.2 beats/L/min; p = 0.02. In conclusion, Sch-PAH patients had less impaired physiological responses to exercise than IPAH subjects with similar resting hemodynamic dysfunction. Our data suggest a more preserved cardiopulmonary response to exercise in Sch-PAH which might be related to its better clinical course compared to IPAH.

  5. Hemodynamic Changes on Color Doppler Flow Imaging and Intravenous Contrast-enhanced Ultrasound for Assessing Transplanted Liver and Early Diagnosis of Complications

    Institute of Scientific and Technical Information of China (English)

    Daozhong HUANG; Yanchao CHEN; Kaiyan LI; Qingping ZHANG

    2008-01-01

    The value of color Doppler flow imaging (CDFI) and intravenous contrast-enhanced ultrasound (CEUS) for assessing the transplanted liver and early diagnosing complications by examining hemodynamic changes was discussed. Seventy-five patients with orthotopic liver transplantation (OLT) underwent CDFI. The following parameters were measured: peak systolic velocity (PS), resistance index (RI) and Doppler perfusion index (DPI) of the hepatic artery (HA), time average velocity (TAV) of portal vein (PV) and velocity of hepatic vein (HV) in different stages post-operation. And 11 patients of them received CEUS. Thirty healthy subjects were enrolled as controls. The results showed that: (1) In 23 patients without obvious complications, TAV of PV within 15 days post-operation was significantly higher than in controls (P<0.05), PS and DPI of HA within 7 days postoperation were lower, but RI was higher than in controls (P<0.05); (2) When the hepatic artery thrombosis (HAT) occurred, PS and DPI of HA were obviously decreased, but TAV of PV significantly increased like a high saw-tooth wave; (3) While rejection occurred, both TAV of PV and PS of HA were decreased with the increase in RI of HA, and the triphasic wave of HV disappeared and displayed as saw-tooth wave; (4) The incidence of biliary complications in liver transplantation was in-creased when DPI was reduced; (5) Seven cases of hepatic carcinoma relapse after OLT demonstrated hyperecho in the arterial phase and hypoecho in the portal and later phase on CEUS; (6) In 2 cases of HA thrombus, there was no visualized enhancement in arterial phase of CEUS, but enhancement during the portal vein and parenchymal phase. It was concluded that the hemodynamic changes of PV, HA and HV in the transplanted liver are valuable for assessing the transplanted liver and early diagnosing complications on CDFI and CEUS.

  6. Peripheral moving-table contrast-enhanced magnetic resonance angiography (CE-MRA) using a prototype 18-channel peripheral vascular coil and scanning parameters optimized to the patient's individual hemodynamics.

    Science.gov (United States)

    Potthast, Silke; Wilson, Gregory J; Wang, Maisie S; Maki, Jeffrey H

    2009-05-01

    To demonstrate that with a priori determination of individual patient hemodynamics, peripheral contrast-enhanced magnetic resonance angiography (pCE-MRA) can be customized to maximize signal-to noise ratio (SNR) and avoid venous enhancement. Using a 1.5T MRI scanner and prototype 18-channel peripheral vascular (PV) coil designed for highly accelerated parallel imaging, geometry (g)-factor maps were determined. SNR-maximized protocols considering the two-dimensional sensitivity encoding (2D SENSE) factor, TE, TR, bandwidth (BW), and flip angle (FA) were precalculated and stored. For each exam, a small aortic timing bolus was performed, followed by dynamic three-dimensional (3D)-MRA of the calf. Using this information, the aorta to pedal artery and calf arteriovenous transit times were measured. This enabled estimation of the maximum upper and middle station acquisition duration to allow lower station acquisition to begin prior to venous arrival. The appropriately succinct SNR-optimized protocol for each station was selected and moving-table pCE-MRA was performed using thigh venous compression and high-relaxivity contrast material. The protocol was successfully applied in 15 patients and all imaging demonstrated good SNR without diagnosis-hindering venous enhancement. By knowing each patient's venous enhancement kinetics, scan parameters can be optimized to utilize maximum possible acquisition time. Some time is added for the timing scans, but in return time-resolved calf CE-MRA, maximized SNR, and decreased risk of venous enhancement are gained.

  7. Rest and stress transluminal attenuation gradient and contrast opacification difference for detection of hemodynamically significant stenoses in patients with suspected coronary artery disease.

    Science.gov (United States)

    Ko, Brian S; Seneviratne, Sujith; Cameron, James D; Gutman, Sarah; Crossett, Marcus; Munnur, Kiran; Meredith, Ian T; Wong, Dennis T L

    2016-07-01

    This study evaluated the feasibility of stress 320 detector CT coronary angiography (CTA) derived transluminal attenuation gradient (TAG320) and contrast opacification (CO) difference to detect hemodynamically significant stenoses as determined by invasive fractional flow reserve (FFR ≤ 0.80). Twenty-seven patients, including 51 vessels on rest CTA were studied. 16 (31 %) vessels were not interpretable on stress CTA largely secondary to motion artefacts. Receiver operating characteristic curve analysis showed a comparable area under the curve (AUC) for rest and stress TAG320 (0.78 and 0.75) which was higher than CTA alone (0.68), and rest and stress CO difference (0.76 and 0.67). Compared with rest CTA, stress CTA demonstrated inferior image quality (Median Likert score 4 vs. 3, P < 0.0001) and required a higher mean radiation exposure (3.2 vs. 5.1 mSv, P < 0.0001). Stress TAG320 and CO difference is less feasible and was not superior in diagnostic performance when compared with rest TAG320 and CO difference.

  8. Time-resolved contrast-enhanced MR angiography: Value of hemodynamic information in the assessment of vascular diseases

    Science.gov (United States)

    Maj, Edyta; Cieszanowski, Andrzej; Rowiński, Olgierd; Wojtaszek, Mikołaj; Szostek, Małgorzata; Tworus, Robert

    2010-01-01

    Summary Background: To assess the quality of images obtained from time-resolved MRA together with the accuracy of this technique in diagnosing vascular diseases and the usefulness of haemodynamic information provided by this method. Material/Methods: The study group included 120 patients with different vascular pathologies excluding of intracranial vessels. All patients underwent time-resolved MRA on 1.5T unit. Results were correlated with other imaging techniques: DSA (n=36), CTA (n=28), Doppler ultrasound (n=71) and intraoperative findings (n=10). Independently, two radiologists evaluated the MRA studies assessing the quality of the images in a 3 point scale (3 – good, 1 – poor), as well as the presence or absence of haemodynamic information (3 – relevant dynamic information, 2 – irrelevant dynamic information, 1 – lack of dynamic information) for different vascular pathologies. Results: Mean quality of MRA examinations was 2.94 (reader A and B) and was similar for different pathologies (kappa value =0.757). The mean grading (reader A and B) for the presence of dynamic information was above 2 for the following pathologies: celiac artery branch pseudoaneurysm (3), vascular malformation (3), subclavian steal syndrome (2.5), Leriche’s syndrome (2.25), aortic dissection (2.06), renal artery stenosis (2.03); and below 2 for: pelvic arterial occlusive disease (1.75), abdominal aortic aneurysm (1.31), carotid artery stenosis (1.1), thoracic aortic aneurysm (1.0). Kappa value was 0.802. The sensitivity was 95%, specificity 96% and positive predictive value 98%. Conclusions: Time-resolved MRA provides good quality images and enables reliable diagnosis of vascular pathologies. PMID:22802762

  9. Biphasic contrast medium injection in cardiac CT: moderate versus high concentration contrast material at identical iodine flux and iodine dose.

    NARCIS (Netherlands)

    Rutten, A.; Meijs, M.F.; Vos, A.M.C.; Seidensticker, P.R.; Prokop, M.

    2010-01-01

    OBJECTIVE: To prospectively investigate the influence of contrast material concentration on enhancement in cardiac CT by using a biphasic single-injection protocol. METHODS: Sixty-four-row multidetector cardiac CT angiography was performed in 159 patients randomised to a moderate or high contrast me

  10. Assessment of hemodynamic changes in the systemic and pulmonary arterial circulation in patients with cystic fibrosis using phase-contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ley, Sebastian; Eichinger, Monika [DKFZ, Department of Radiology (E010), Heidelberg (Germany); Johannes Gutenberg University, Department of Radiology, University Hospital Mainz, Mainz (Germany); Puderbach, Michael; Fink, Christian; Plathow, Christian; Kauczor, Hans-Ulrich [DKFZ, Department of Radiology (E010), Heidelberg (Germany); Teiner, Susanne [University of Heidelberg, Department of Pediatric Radiology, Heidelberg (Germany); Wiebel, Matthias [Thoraxklinik am Universitaetsklinikum, Department of Pulmonology, Heidelberg (Germany); Mueller, Frank-Michael [University of Heidelberg, Department of Pediatric Pulmonology, Heidelberg (Germany)

    2005-08-01

    Cystic fibrosis (CF) leads to disabling lung disease and pulmonary hypertension (PH). The goal of this study was to assess the hemodynamics in the systemic and pulmonary arterial circulation of patients with CF using MRI. Ten patients with CF and 15 healthy volunteers were examined (1.5-T MRI). Phase-contrast flow measurements were assessed in the ascending aorta, pulmonary trunc, and the left and right pulmonary arteries (PA), resulting in the following parameters: peak velocity (PV) (centimeters per second) velocity rise gradient (VRG), time to PV (milliseconds), and the average area (centimeters squared). The blood flow ratio between the right and left lungs and the bronchosystemic shunt were calculated. For the ascending aorta and pulmonary trunc no parameter was significantly different between both populations. In the right PA a significantly lower PV (p=0.001) and VRG (p=0.02) was found. In the left PA there was a significantly (p=0.007) lower PV but no significant (p=0.07) difference between the VRG. The areas of the right (p=0.08) and left (p=0.5) PA were not significantly enlarged. For the volunteers a linear increase of PV in both PA was found with age, while it decreased in patients with CF. The blood flow distribution (right/left lung) showed no significant (p=0.7) difference between the groups. There was a significantly (p<0.001) higher bronchosystemic shunt volume in patients with CF (1.3 l/min) than in volunteers (0.1 l/min). Magnetic resonance based flow measurements in the right and left PA showed first indications for early development of PH. The significant increase in bronchosystemic shunt volume might be indicative fo the extent of parenchymal changes. (orig.)

  11. Metabolic changes assessed by MRS accurately reflect brain function during drug-induced epilepsy in mice in contrast to fMRI-based hemodynamic readouts.

    Science.gov (United States)

    Seuwen, Aline; Schroeter, Aileen; Grandjean, Joanes; Rudin, Markus

    2015-10-15

    Functional proton magnetic resonance spectroscopy (1H-MRS) enables the non-invasive assessment of neural activity by measuring signals arising from endogenous metabolites in a time resolved manner. Proof-of-principle of this approach has been demonstrated in humans and rats; yet functional 1H-MRS has not been applied in mice so far, although it would be of considerable interest given the many genetically engineered models of neurological disorders established in this species only. Mouse 1H-MRS is challenging as the high demands on spatial resolution typically result in long data acquisition times not commensurable with functional studies. Here, we propose an approach based on spectroscopic imaging in combination with the acquisition of the free induction decay to maximize signal intensity. Highly resolved metabolite maps have been recorded from mouse brain with 12 min temporal resolution. This enabled monitoring of metabolic changes following the administration of bicuculline, a GABA-A receptor antagonist. Changes in levels of metabolites involved in energy metabolism (lactate and phosphocreatine) and neurotransmitters (glutamate) were investigated in a region-dependent manner and shown to scale with the bicuculline dose. GABAergic inhibition induced spectral changes characteristic for increased neurotransmitter turnover and oxidative stress. In contrast to metabolic readouts, BOLD and CBV fMRI responses did not scale with the bicuculline dose indicative of the failure of neurovascular coupling. Nevertheless fMRI measurements supported the notion of increased oxidative stress revealed by functional MRS. Hence, the combined analysis of metabolic and hemodynamic changes in response to stimulation provides complementary insight into processes associated with neural activity.

  12. CONTRAST

    DEFF Research Database (Denmark)

    Kristensen, Thomas Krogsgaard

    2007-01-01

    Dette er en afrapportering fra den årlige CONTRAST workshop, der i 2007 blev afholdt i Yaoundé, Cameroon.......Dette er en afrapportering fra den årlige CONTRAST workshop, der i 2007 blev afholdt i Yaoundé, Cameroon....

  13. Comparison of 4D flow and 2D velocity-encoded phase contrast MRI sequences for the evaluation of aortic hemodynamics.

    Science.gov (United States)

    Bollache, Emilie; van Ooij, Pim; Powell, Alex; Carr, James; Markl, Michael; Barker, Alex J

    2016-10-01

    The purpose of this study was to compare aortic flow and velocity quantification using 4D flow MRI and 2D CINE phase-contrast (PC)-MRI with either one-directional (2D-1dir) or three-directional (2D-3dir) velocity encoding. 15 healthy volunteers (51 ± 19 years) underwent MRI including (1) breath-holding 2D-1dir and (2) free breathing 2D-3dir PC-MRI in planes orthogonal to the ascending (AA) and descending (DA) aorta, as well as (3) free breathing 4D flow MRI with full thoracic aorta coverage. Flow quantification included the co-registration of the 2D PC acquisition planes with 4D flow MRI data, AA and DA segmentation, and calculation of AA and DA peak systolic velocity, peak flow and net flow volume for all sequences. Additionally, the 2D-3dir velocity taking into account the through-plane component only was used to obtain results analogous to a free breathing 2D-1dir acquisition. Good agreement was found between 4D flow and 2D-3dir peak velocity (differences = -3 to 6 %), peak flow (-7 %) and net volume (-14 to -9 %). In contrast, breath-holding 2D-1dir measurements exhibited indices significantly lower than free breathing 2D-3dir and 2D-1dir (differences = -35 to -7 %, p < 0.05). Finally, high correlations (r ≥ 0.97) were obtained for indices estimated with or without eddy current correction, with the lowest correlation observed for net volume. 4D flow and 2D-3dir aortic hemodynamic indices were in concordance. However, differences between respiration state and 2D-1dir and 2D-3dir measurements indicate that reference values should be established according to the PC-MRI sequence, especially for the widely used net flow (e.g. stroke volume in the AA).

  14. Epidemiology of contrast material-induced nephropathy in the era of hydration.

    NARCIS (Netherlands)

    Balemans, C.E.A.; Reichert, L.J.M.; Schelven, B.I. van; Brand, Jan van den; Wetzels, J.F.M.

    2012-01-01

    PURPOSE: To evaluate the incidence of contrast material-induced nephropathy (CIN) in patients with an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m(2) who received intravenous contrast media and underwent treatment in accordance with current guidelines and to determine ri

  15. Omnidirectional Photonic Band Gap Using Low Refractive Index Contrast Materials and its Application in Optical Waveguides

    KAUST Repository

    Vidal Faez, Angelo

    2012-07-01

    Researchers have argued for many years that one of the conditions for omnidirectional reflection in a one-dimensional photonic crystal is a strong refractive index contrast between the two constituent dielectric materials. Using numerical simulations and the theory of Anderson localization of light, in this work we demonstrate that an omnidirectional band gap can indeed be created utilizing low refractive index contrast materials when they are arranged in a disordered manner. Moreover, the size of the omnidirectional band gap becomes a controllable parameter, which now depends on the number of layers and not only on the refractive index contrast of the system, as it is widely accepted. This achievement constitutes a major breakthrough in the field since it allows for the development of cheaper and more efficient technologies. Of particular interest is the case of high index contrast one-dimensional photonic crystal fibers, where the propagation losses are mainly due to increased optical scattering from sidewall roughness at the interfaces of high index contrast materials. By using low index contrast materials these losses can be reduced dramatically, while maintaining the confinement capability of the waveguide. This is just one of many applications that could be proven useful for this discovery.

  16. Physiological Evaluation of a Student in E-learning Sessions by Hemodynamic Responses

    Science.gov (United States)

    Nomura, Shusaku; Irfan, C. M. Althaff; Yamagishi, Takao; Kurosawa, Yoshimasa; Yajima, Kuniaki; Nakahira, Katsuko T.; Ogawa, Nobuyuki; Handri, Santoso; Fukumura, Yoshimi

    In this study, a novel approach towards the evaluation of students in e-learning sessions is regarded; the physiological responses of the students who were engaged in e-learning materials were investigated. Among a full battery of physiological signals, we focused on human hemodynamic activity, which is represented by the blood pressure. The past hemodynamic studies on mental stress showed that the difference in subject's stress coping style, i.e., active and passive coping, induced different hemodynamic responses. Such a variety of stress coping styles is also anticipated to be prevailing in attendees of e-learning course. In the experiment, the hemodynamic responses of the students who were engaged in the e-learning session were investigated with two considerably contrasting e-learning materials, one is characterized by an interactive material and the other is by non-interactive material. As a developing result, a particular hemodynamic pattern, which is involved in the subject's active coping, was observed in the interactive condition, and that of passive coping was observed in the non-interactive condition, whereas there was no significant difference in the score of questionnaire on the materials. These results thus led to an idea of the objective evaluation of the attendees of e-learning courses.

  17. Extravasation of radiographic contrast material and compartment syndrome in the hand: a case report

    Directory of Open Access Journals (Sweden)

    Torrededia Laura

    2011-02-01

    Full Text Available Abstract Radiocontrast agents are a type of medical contrast material used to improve the visibility of internal bodily structures in X-ray based imaging techniques such as computed tomography (CT or radiography. Radiocontrast agents are typically iodine or barium compounds. Extravasation of contrast is a possible complication of imaging studies performed with contrasts. Most extravasations cause minimal swelling or erythema, however, skin necrosis, ulceration and compartment syndrome may occur with extravasation of large volumes of contrast. A case report is presented in which significant extravasation of contrast was caused while injecting the contrast intravenously into the back of the hand of a 50 year old patient during computed tomography. The patient was undergoing chemotherapy. The patient developed a compartment syndrome and a fasciotomy was required. Treatment options are outlined and emphasis is made on prevention of this iatrogenic complication. Some of the preventive measures to avoid these complications include use of non-ionic contrast (low osmolarity, careful choice of the site of intravenous administration, and close monitoring of the patient during injection of contrast to minimize or prevent extravasation injuries. Clear information to patients and prompt recognition of the complication can allow for other non-surgical treatment options than the one required in this case.

  18. An Image-Domain Contrast Material Extraction Method for Dual-Energy Computed Tomography.

    Science.gov (United States)

    Lambert, Jack W; Sun, Yuxin; Gould, Robert G; Ohliger, Michael A; Li, Zhixi; Yeh, Benjamin M

    2017-04-01

    Conventional material decomposition techniques for dual-energy computed tomography (CT) assume mass or volume conservation, where the CT number of each voxel is fully assigned to predefined materials. We present an image-domain contrast material extraction process (CMEP) method that preferentially extracts contrast-producing materials while leaving the remaining image intact. Image processing freeware (Fiji) is used to perform consecutive arithmetic operations on a dual-energy ratio map to generate masks, which are then applied to the original images to generate material-specific images. First, a low-energy image is divided by a high-energy image to generate a ratio map. The ratio map is then split into material-specific masks. Ratio intervals known to correspond to particular materials (eg, iodine, calcium) are assigned a multiplier of 1, whereas ratio values in between these intervals are assigned linear gradients from 0 to 1. The masks are then multiplied by an original CT image to produce material-specific images. The method was tested quantitatively at dual-source CT and rapid kVp-switching CT (RSCT) with phantoms using pure and mixed formulations of tungsten, calcium, and iodine. Errors were evaluated by comparing the known material concentrations with those derived from the CMEP material-specific images. Further qualitative evaluation was performed in vivo at RSCT with a rabbit model using identical CMEP parameters to the phantom. Orally administered tungsten, vascularly administered iodine, and skeletal calcium were used as the 3 contrast materials. All 5 material combinations-tungsten, iodine, and calcium, and mixtures of tungsten-calcium and iodine-calcium-showed distinct dual-energy ratios, largely independent of material concentration at both dual-source CT and RSCT. The CMEP was successful in both phantoms and in vivo. For pure contrast materials in the phantom, the maximum error between the known and CMEP-derived material concentrations was 0.9 mg

  19. Optimum iodine concentration of contrast material through microcatheters: hydrodynamic analysis of experimental results

    Science.gov (United States)

    Yamauchi, Teiyu; Furui, Shigeru; Harasawa, Arimi; Ishimura, Makoto; Imai, Tatsuhiko; Hayashi, Toshimitsu

    2002-07-01

    It is important to increase the iodine delivery rate (I), that is the iodine concentration of the contrast material (C) × the flow rate of the contrast material (Q), through a catheter to obtain high quality arteriograms. The iodine delivery rate varies depending on the iodine concentration of the contrast material. The purpose of this study is to estimate the optimum iodine concentration (Copt) of contrast material (i.e. the iodine concentration at which I becomes maximum) through a microcatheter of a given length (L), inner diameter (D) and injection pressure (P). Iohexol, ioversol and iopamidol of 11-12 iodine concentrations (140-350, 160-350 or 160-370 mg cm-3) at 37 °C are used. I and Reynolds number (Re) of the flow of each contrast material through four microcatheters (0.49-0.68 mm in inner diameter, 1000-1500 mm in length) at injection pressures of 1.38, 2.76, 4.14 and 5.52 × 106 Pa (200, 400, 600 and 800 pounds per square inch) are obtained experimentally. The relationships between I and C and between I and Re are examined for each catheter and injection pressure. Copt is 160-280 mg cm-3 for iohexol, 180-280 mg cm-3 for ioversol and 200-300 mg cm-3 for iopamidol. I becomes maximum when Re approximates the critical Reynolds number (Re ≃ 2300). Utilizing this principle, we can estimate Copt and its flow rate through a microcatheter of a given L, D and P.

  20. Improved quantification of cerebral hemodynamics using individualized time thresholds for assessment of peak enhancement parameters derived from dynamic susceptibility contrast enhanced magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Christian Nasel

    Full Text Available Assessment of cerebral ischemia often employs dynamic susceptibility contrast enhanced magnetic resonance imaging (DSC-MRI with evaluation of various peak enhancement time parameters. All of these parameters use a single time threshold to judge the maximum tolerable peak enhancement delay that is supposed to reliably differentiate sufficient from critical perfusion. As the validity of this single threshold approach still remains unclear, in this study, (1 the definition of a threshold on an individual patient-basis, nevertheless (2 preserving the comparability of the data, was investigated.The histogram of time-to-peak (TTP values derived from DSC-MRI, the so-called TTP-distribution curve (TDC, was modeled using a double-Gaussian model in 61 patients without severe cerebrovascular disease. Particular model-based zf-scores were used to describe the arterial, parenchymal and venous bolus-transit phase as time intervals Ia,p,v. Their durations (delta Ia,p,v, were then considered as maximum TTP-delays of each phase.Mean-R2 for the model-fit was 0.967. Based on the generic zf-scores the proposed bolus transit phases could be differentiated. The Ip-interval reliably depicted the parenchymal bolus-transit phase with durations of 3.4 s-10.1 s (median = 4.3s, where an increase with age was noted (∼30 ms/year.Individual threshold-adjustment seems rational since regular bolus-transit durations in brain parenchyma obtained from the TDC overlap considerably with recommended critical TTP-thresholds of 4 s-8 s. The parenchymal transit time derived from the proposed model may be utilized to individually correct TTP-thresholds, thereby potentially improving the detection of critical perfusion.

  1. The properties of optimal two-dimensional phononic crystals with different material contrasts

    Science.gov (United States)

    Liu, Zong-Fa; Wu, Bin; He, Cun-Fu

    2016-09-01

    By modifying the spatial distribution of constituent material phases, phononic crystals (PnCs) can be designed to exhibit band gaps within which sound and vibration cannot propagate. In this paper, the developed topology optimization method (TOM), based on genetic algorithms (GAs) and the finite element method (FEM), is proposed to design two-dimensional (2D) solid PnC structures composed of two contrasting elastic materials. The PnCs have the lowest order band gap that is the third band gap for the coupled mode, the first band gap for the shear mode or the XY 34 Z band gap for the mixed mode. Moreover, the effects of the ratios of contrasting material properties on the optimal layout of unit cells and the corresponding phononic band gaps (PBGs) are investigated. The results indicate that the topology of the optimal PnCs and corresponding band gaps varies with the change of material contrasts. The law can be used for the rapid design of desired PnC structures.

  2. Factor affecting contrast enhancement of the hepatic parenchyma in CT after intravenous injection of iodinated contrast material; Parametres influencant le rehaussement parenchymateux hepatique en tomodensitometrie apres injection intraveineuse de produit de contraste iode

    Energy Technology Data Exchange (ETDEWEB)

    Bonaldi, V.M.; Garcia, P.; Bret, P.M. [McGill Univ., Montreal, PQ (Canada); Bonaldi, V.M. [Nice Univ., 06 (France); Garcia, P. [Clinique Protestante, 69 - Lyon (France)

    1997-04-01

    With the widespread use of spiral CT, a complete reassessment of intravenous injection of contrast material for body computed tomography is necessary. An optimal administration of contrast material with respect to scan timing is indeed more critical with spiral CT. Numerous factors affect hepatic contrast enhancement time-attenuation curves after injection of contrast material into a peripheral vein. Some are patient related, while other result from the modalities of administration of the iodinated agent. The objective of this article is to review the most contributive factors in liver enhancement after iodine injection. Knowledge of these factors can optimize the use of spiral CT, with the expected benefit of saving costs in contrast material. (authors). 39 refs.

  3. Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, N.G. [University of Otago, Department of Radiology, Christchurch (New Zealand); Butler, A.P. [University of Otago, Department of Radiology, Christchurch (New Zealand); University of Canterbury, Physics and Astronomy, Christchurch (New Zealand); Scott, N.J.A. [University of Otago, Department of Medicine, Christchurch (New Zealand); Cook, N.J. [Christchurch Hospital, Medical Physics and Bioengineering, Christchurch (New Zealand); Butzer, J.S. [Karlsruhe Institute of Technology, Physics Department, Karlsruhe (Germany); Schleich, N. [University of Canterbury, Physics and Astronomy, Christchurch (New Zealand); Christchurch Hospital, Medical Physics and Bioengineering, Christchurch (New Zealand); Firsching, M. [Friedrich Alexander University, Physics Department, Erlangen (Germany); Grasset, R.; Ruiter, N. de [University of Canterbury, Hitlab NZ, Christchurch (New Zealand); Campbell, M. [European Organisation for Nuclear Research, Physics Section, Geneva (Switzerland); Butler, P.H. [University of Canterbury, Physics and Astronomy, Christchurch (New Zealand)

    2010-09-15

    Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium. We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 {mu}A). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D. Iodinated and barium contrast material was spectrally distinct from soft tissue and bone in all six mice. Calcium, iodine and barium were displayed as separate channels on 3D colour images at <55 {mu}m isotropic voxels. Spectral CT distinguishes contrast agents with K-edges only 4 keV apart. Multi-contrast imaging and molecular CT are potential future applications. (orig.)

  4. Multi-contrast 3D X-ray imaging of porous and composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Sarapata, Adrian; Herzen, Julia [Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Ruiz-Yaniz, Maite [Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); European Synchrotron Radiation Facility, 38000 Grenoble (France); Zanette, Irene [Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom); Rack, Alexander [European Synchrotron Radiation Facility, 38000 Grenoble (France); Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Institut für Diagnostische und Interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, 81675 München (Germany)

    2015-04-13

    Grating-based X-ray computed tomography allows for simultaneous and nondestructive determination of the full X-ray complex index of refraction and the scattering coefficient distribution inside an object in three dimensions. Its multi-contrast capabilities combined with a high resolution of a few micrometers make it a suitable tool for assessing multiple phases inside porous and composite materials such as concrete. Here, we present quantitative results of a proof-of-principle experiment performed on a concrete sample. Thanks to the complementarity of the contrast channels, more concrete phases could be distinguished than in conventional attenuation-based imaging. The phase-contrast reconstruction shows high contrast between the hardened cement paste and the aggregates and thus allows easy 3D segmentation. Thanks to the dark-field image, micro-cracks inside the coarse aggregates are visible. We believe that these results are extremely interesting in the field of porous and composite materials studies because of unique information provided by grating interferometry in a non-destructive way.

  5. Suitability of new anode materials in mammography: dose and subject contrast considerations using Monte Carlo simulation.

    Science.gov (United States)

    Delis, H; Spyrou, G; Costaridou, L; Tzanakos, G; Panayiotakis, G

    2006-11-01

    Mammography is the technique with the highest sensitivity and specificity, for the early detection of nonpalpable lesions associated with breast cancer. As screening mammography refers to asymptomatic women, the task of optimization between the image quality and the radiation dose is critical. A way toward optimization could be the introduction of new anode materials. A method for producing the x-ray spectra of different anode/filter combinations is proposed. The performance of several mammographic spectra, produced by both existing and theoretical anode materials, is evaluated, with respect to their dose and subject contrast characteristics, using a Monte Carlo simulation. The mammographic performance is evaluated utilizing a properly designed mathematical phantom with embedded inhomogeneities, irradiated with different spectra, based on combinations of conventional and new (Ru, Ag) anode materials, with several filters (Mo, Rh, Ru, Ag, Nb, Al). An earlier developed and validated Monte Carlo model, for deriving both image and dose characteristics in mammography, was utilized and overall performance results were derived in terms of subject contrast to dose ratio and squared subject contrast to dose ratio. Results demonstrate that soft spectra, mainly produced from Mo, Rh, and Ru anodes and filtered with k-edge filters, provide increased subject contrast for inhomogeneities of both small size, simulating microcalcifications and low density, simulating masses. The harder spectra (W and Ag anode) come short in the discrimination task but demonstrate improved performance when considering the dose delivered to the breast tissue. As far as the overall performance is concerned, new theoretical spectra demonstrate a noticeable good performance that is similar, and in some cases better compared to commonly used systems, stressing the possibility of introducing new materials in mammographic practice as a possible contribution to its optimization task. In the overall

  6. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    Science.gov (United States)

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm-1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm-1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm-1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility was

  7. Low tube voltage and low contrast material volume cerebral CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Song [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Xuzhou Medical College, School of Medical Imaging, Xuzhou, Jiangsu (China); Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Meinel, Felix G.; McQuiston, Andrew D. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Zhou, Chang Sheng; Qi, Li [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2014-07-15

    To evaluate the image quality, radiation dose and diagnostic accuracy of low kVp and low contrast material volume cerebral CT angiography (CTA) in intracranial aneurysm detection. One hundred twenty patients were randomly divided into three groups (n = 40 for each): Group A, 70 ml iodinated contrast agent/120 kVp; group B, 30 ml/100 kVp; group C, 30 ml/80 kVp. The CT numbers, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Subjective image quality was evaluated. For patients undergoing DSA, diagnostic accuracy of CTA was calculated with DSA as reference standard and compared. CT numbers of ICA and MCA were higher in groups B and C than in group A (P < 0.01). SNR and CNR in groups A and B were higher than in group C (both P < 0.05). There was no difference in subjective image quality among the three groups (P = 0.939). Diagnostic accuracy for aneurysm detection among these groups had no statistical difference (P = 1.00). Compared with group A, the radiation dose of groups B and C was decreased by 45 % and 74 %. Cerebral CTA at 100 or 80 kVp using 30 ml contrast agent can obtain diagnostic image quality with a low radiation dose while maintaining the same diagnostic accuracy for aneurysm detection. (orig.)

  8. Search for novel contrast materials in dual-energy x-ray breast imaging using theoretical modeling of contrast-to-noise ratio.

    Science.gov (United States)

    Karunamuni, R; Maidment, A D A

    2014-08-01

    Contrast-enhanced (CE) dual-energy (DE) x-ray breast imaging uses a low- and high-energy x-ray spectral pair to eliminate soft-tissue signal variation and thereby increase the detectability of exogenous imaging agents. Currently, CEDE breast imaging is performed with iodinated contrast agents. These compounds are limited by several deficiencies, including rapid clearance and poor tumor targeting ability. The purpose of this work is to identify novel contrast materials whose contrast-to-noise ratio (CNR) is comparable or superior to that of iodine in the mammographic energy range. A monoenergetic DE subtraction framework was developed to calculate the DE signal intensity resulting from the logarithmic subtraction of the low- and high-energy signal intensities. A weighting factor is calculated to remove the dependence of the DE signal on the glandularity of the breast tissue. Using the DE signal intensity and weighting factor, the CNR for materials with atomic numbers (Z) ranging from 1 to 79 are computed for energy pairs between 10 and 50 keV. A group of materials with atomic numbers ranging from 42 to 63 were identified to exhibit the highest levels of CNR in the mammographic energy range. Several of these materials have been formulated as nanoparticles for various applications but none, apart from iodine, have been investigated as CEDE breast imaging agents. Within this group of materials, the necessary dose fraction to the LE image decreases as the atomic number increases. By reducing the dose to the LE image, the DE subtraction technique will not provide an anatomical image of sufficient quality to accompany the contrast information. Therefore, materials with Z from 42 to 52 provide nearly optimal values of CNR with energy pairs and dose fractions that provide good anatomical images. This work is intended to inspire further research into new materials for optimized CEDE breast functional imaging.

  9. Childhood moyamoya disease: hemodynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tzika, A.A. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Robertson, R.L. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Barnes, P.D. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Vajapeyam, S. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Burrows, P.E. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Treves, S.T. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Scott, R.M. l [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States)

    1997-09-01

    Background. Childhood moyamoya disease is a rare progressive cerebrovascular disease. Objective. To evaluate cerebral hemodynamics using dynamic Gd-DTPA-enhanced imaging in children with moyamoya disease. Materials and methods. Eight children (2-11 years of age) with the clinical and angiographic findings typical of moyamoya disease, before and/or after surgical intervention (pial synangiosis), underwent conventional MR imaging (MRI) and hemodynamic MR imaging (HMRI). HMRI used a spoiled gradient-echo with low flip angle (10 deg) and long TE (TR/TE = 24/15 ms) to minimize T 1 effects and emphasize T 2{sup *} weighting. Raw and calculated hemodynamic images were reviewed. Three-dimensional time-of-flight MR angiography (MRA) and perfusion brain single photon emission computed tomography (SPECT) were also performed. Results. Abnormal hemodynamic maps resulting from vascular stenosis or occlusion and basal collaterals were observed in six patient studies. HMRI depicted perfusion dynamics of affected cerebrovascular territories, detected cortical perfusion deficits, and complemented conventional MRI and MRA. HMRI findings were consistent with those of catheter angiography and perfusion SPECT. Conclusion. Our preliminary experience suggests that HMRI may be of value in the preoperative and postoperative evaluation of surgical interventions in moyamoya disease. (orig.). With 4 figs., 3 tabs.

  10. Effect of a Material Contrast on a Dynamic Rupture: 3-D

    Science.gov (United States)

    Harris, R. A.; Day, S. M.

    2003-12-01

    We use numerical simulations of spontaneously propagating ruptures to examine the effect of a material contrast on earthquake dynamics. We specifically study the case of a lateral contrast whereby the fault is the boundary between two different rock-types. This scenario was previously studied in two-dimensions by Harris and Day [BSSA, 1997], and Andrews and Ben-Zion [JGR, 1997], in addition to subsequent 2-D studies, but it has not been known if the two-dimensional results are applicable to the real three-dimensional world. The addition of the third dimension implies a transition from pure mode II (i.e., plane-strain) to mixed-mode crack dynamics, which is more complicated since in mode II the shear and normal stresses are coupled whereas in mode III (i.e., anti-plane strain) they are not coupled. We use a slip-weakening fracture criterion and examine the effect on an earthquake rupture of material contrasts of up to 50 percent across the fault zone. We find a surprisingly good agreement between our earlier 2-D results, and our 3-D results for along-strike propagation. We find that the analytical solution presented in Harris and Day [BSSA, 1997] does an excellent job at predicting the bilateral, along-strike rupture velocities for the three-dimensional situation. In contrast, the along-dip propagation behaves much as expected for a purely mode-III rupture, with the rupture velocities up-dip and down-dip showing the expected symmetries.

  11. Carotid and cerebral CT angiography using low volume of iodinated contrast material and low tube voltage.

    Science.gov (United States)

    Kayan, M; Demirtas, H; Türker, Y; Kayan, F; Çetinkaya, G; Kara, M; Orhan Çelik, A; Umul, A; Yılmaz, Ö; Recep Aktaş, A

    2016-11-01

    To evaluate image quality of carotid computed tomography angiography (CTA) using a low voltage (80kV) and low amount of iodinated contrast material. A total of 101 patients referred for carotid CTA were randomly assigned to receive a specific protocol. In group A patients received intravenous administration of contrast material at a dose of 1mL/kg and CTA examinations were performed at 100kV. In group B, patients received intravenous administration of contrast material at a dose of 0.5mL/kg and CTA examinations were performed at 80kV. The same nonionic iodinated contrast material containing 370mg of iodine per mL was used in both groups. Attenuation values were measured from the center of specific arterial segments using regions of interest. Attenuation values above 300HU were accepted as significant. Institutional review board approval was obtained. A total of 50 patients were included in group A (38 men, 12 women; mean age, 63.56 years±13.18 [SD]) and 51 patients in group B (33 men, 18 women; mean age, 59.60 years±16.63 [SD]). A total of 1615 arterial segments (1515 common carotid artery-middle cerebral artery and 101 aortic arches) were analyzed. Venous contamination was not observed in either group. The mean attenuation values of all arterial segments in both groups were greater than 300HU. Mean arterial attenuation value in group B (499.22HU±97.25 [SD]) was significantly greater than in group A (374.36HU±73.79 [SD]) (P70%) was detected in 2 segments in group A and in 3 segments in group B, while grade IV stenosis (occlusion) was detected in 2 segments in group B. Distal common carotid artery dissection was detected in 1 patient and aortic dissection was detected in 1 patient in group B. Total dose-length product (DLP) value was significantly greater in group A (225.74mGy·cm±21.80 [SD]) than in group B (116.60mGy·cm±21.22 [SD]) (Pmaterial. This provides good image quality with low radiation dose. Copyright © 2016 Editions françaises de radiologie

  12. X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2013-04-15

    Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n= 1 -{delta}+i {beta}. The real part of the refractive index, specifically the refractive index decrement ({delta}), over the energy range of 5-50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine {delta}. At each x-ray photon energy, the absolute percent difference in {delta} between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient {mu}, and hence {beta}, was considered to be best representative of that breast tissue. Results: Over the energy range of 5-50 keV, while the {delta} of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the {mu} of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the {delta} of BR10 and adipose tissue-equivalent material were within 1% of

  13. A novel quantitative imaging technique for material differentiation based on differential phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-04-01

    Compared to single energy CT, which provides information only about the x-ray linear attenuation coefficients, dual energy CT is able to obtain the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual energy CT, a novel quantitative imaging method based on phase contrast CT is described. Rather than requiring two scans with different x-ray photon energies, diffraction grating-based phase contrast CT is capable of reconstructing images of both the linear attenuation and refractive index decrement from a single scan. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Experimental results demonstrate that: (1) electron density can be accurately determined from refractive index decrement through a linear relationship; and (2) effective atomic number can be explicitly derived from the ratio of linear attenuation to refractive index decrement, using a simple function, i.e., a power function plus a constant. The presented method will shed insight into the field of material separation and find its use in medical and non-medical applications.

  14. Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE

    CERN Document Server

    Anderson, NG; Firsching, M; de Ruiter, N; Schleich, N; Butzer, J S; Cook, N J; Grasset, R; Campbell, M; Scott, N J A; Anderson, N G

    2010-01-01

    Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium. We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 A mu A). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D. Iodinated and barium contrast material was spectrally distinct f...

  15. High-resolution Z-contrast imaging and EELS study of functional oxide materials.

    Science.gov (United States)

    Klie, Robert F; Zhao, Yuan; Yang, Guang; Zhu, Yimei

    2008-08-01

    Functional complex-oxide materials show a wide variety of properties and behaviors that cannot be found in any other class of materials, including high-temperature superconductivity and colossal magneto resistance. Consequently, this group of oxide materials has become the focus of many experimental as well as theoretical studies, aiming at understanding the fundamental mechanisms and properties that govern these complex structures. Here, we will review our high-resolution Z-contrast imaging and electron energy-loss studies of two complex-oxide materials systems, more specifically low-angle tilt grain-boundaries in YBa(2)Cu(3)O(7) (YBCO), and the spin-state transition in LaCoO(3). It will be shown that the O K-edge pre-peak can be used to quantify the hole-concentration in the vicinity of the dislocation core in YBCO, as well as to determine the Co(3+) spin-state in LaCoO(3).

  16. Applications of Secondary Electron Composition Contrast Imaging Method in Microstructure Studies on Heterojunction Semiconductor Devices and Multilayer Materials

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+-Si1-xGex/p-Si heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.

  17. A triphenylamine-based benzoxazole derivative as a high-contrast piezofluorochromic material induced by protonation.

    Science.gov (United States)

    Xue, Pengchong; Chen, Peng; Jia, Junhui; Xu, Qiuxia; Sun, Jiabao; Yao, Boqi; Zhang, Zhenqi; Lu, Ran

    2014-03-11

    A triphenylamine-based benzoxazole derivative exhibits a low contrast piezofluorochromic behavior under external pressure, and a high-contrast fluorescence change induced by protonation can be observed.

  18. CT fluoroscopy-assisted cervical transforaminal steroid injection: tips, traps, and use of contrast material.

    Science.gov (United States)

    Hoang, Jenny K; Apostol, Marc A; Kranz, Peter G; Kilani, Ramsey K; Taylor, Jeffrey N; Gray, Linda; Lascola, Christopher D

    2010-10-01

    CT fluoroscopy-assisted cervical transforaminal steroid injection is an effective therapeutic option for cervical radiculopathy, yet it is approached with trepidation by some interventionalists. CT fluoroscopy is superior to conventional fluoroscopy for delineating complex anatomic relations in the neck but must be combined with careful technique to avoid rare but serious complications. We describe the anatomy of the neural foramen, our technique of CT fluoroscopy-assisted cervical transforaminal steroid injection, and the CT appearance of appropriate and inappropriate needle positions. Understanding anatomy will help to avoid complications and optimize the therapeutic potential of cervical transforaminal steroid injection. Use of contrast material for CT fluoroscopic guidance facilitates appropriate needle positioning and reduces the risk of complications.

  19. Feasibility of contrast material volume reduction in coronary artery imaging using 320-slice volume CT

    Energy Technology Data Exchange (ETDEWEB)

    Hein, Patrick A.; May, Juliane; Rogalla, Patrik; Hamm, Bernd; Lembcke, Alexander [Charite-University Hospital, Department of Radiology, Berlin (Germany); Butler, Craig [Charite-University Hospital, Department of Radiology, Berlin (Germany); University of Alberta, Department of Cardiology, Edmonton, Alberta (Canada)

    2010-06-15

    To assess reduced volumes of contrast agent on image quality for coronary computed tomography angiography (CCTA) by using single-beat cardiac imaging with 320-slice CT. Forty consecutive male patients (mean age: 55.8 years) undergoing CCTA with body weight {<=}85 kg, heart rate {<=}65 bpm, and ejection fraction {>=}55% were included. Image acquisition protocol was standardized (120 kV, 400 mA, and prospective ECG-triggered single-beat nonspiral CCTA). Patients were randomly assigned to one of four groups (G1: received 40 ml, G2: 50 ml, G3: 60 ml, G4: 70 ml). Groups were compared with respect to aortic attenuation, image noise, and image quality. CT values (mean {+-} standard deviation) in the aortic root were measured as 423 {+-} 38 HU in G1, and 471 {+-} 68, 463 {+-} 60, and 476 {+-} 78 HU in G2-4, respectively. There were no statistically significant differences in attenuation among the groups (P > 0.068). All 40 CT datasets were rated diagnostic, and image noise and image quality were not statistically different among groups. Using 320-slice volume CT, diagnostic image quality can be achieved with 40 ml of contrast material in CCTA in patients with normal body weight, cardiac function, and low heart rate. (orig.)

  20. Converting strain maps into elasticity maps for materials with small contrast

    Science.gov (United States)

    Bellis, Cédric

    2017-01-01

    This study addresses the question of the quantitative reconstruction of heterogeneous distributions of isotropic elastic moduli from full strain field data. This parameter identification problem exposes the need for a local reconstruction procedure that is investigated here in the case of materials with small contrast. To begin with the integral formulation framework for the periodic linear elasticity problem, first- and second-order asymptotics are retained for the strain field solution and the effective elasticity tensor. Properties of the featured Green's tensor are investigated to characterize its decomposition into an isotropic term and an orthogonal part. The former is then shown to define a local contribution to the volume integral equations considered. Based on this property, then the combination of multiple strain field solutions corresponding to well-chosen applied macroscopic strains is shown to lead to a set of local and uncoupled identities relating, respectively, the bulk and shear moduli to the spherical and deviatoric components of the strain fields. Valid at the first-order in the weak contrast limit, such relations permit point-wise conversions of strain maps into elasticity maps. Furthermore, it is also shown that for macroscopically isotropic material configurations a single strain field solution is actually sufficient to reconstruct either the bulk or the shear modulus distribution. Those results are then revisited in the case of bounded media. Finally, some sets of analytical and numerical examples are provided for comparison and to illustrate the relevance of the obtained strain-modulus local equations for a parameter identification method based on full-field data.

  1. The importance of hemodynamic monitoring in mitrocuspid surgery

    OpenAIRE

    Dobrić Biljana J.; Petrović Jasna S.; Radovanović Ninoslav D.

    2006-01-01

    Introduction. Untreated mitral valve disease is associated with marked hemodynamic disorders, low ejection fraction (EF) and poor perfusion. The study aimed to explore the importance of hemodynamic monitoring in intraoperative evaluation and treatment of these patients. Material and methods. This prospective study included 85 patients: group I: 41 patients, EF<40%; group II: 44 patients, EF>40%. Hemodynamic parameters were recorded after initation of anesthesia (1), after sternotomy (2)...

  2. Contrasting glass and plastic material requirements for reflective and refractive CPV solar systems

    Science.gov (United States)

    Horne, Steve; Krevor, David

    2012-10-01

    Concentrator PhotoVoltaic (CPV) solar energy systems concentrate the sun 500 - 1,000 times or more, in order to take economic advantage of the most advanced and efficient solar cells. The two prevalent system architectures use either reflective glass optics - such as based on a Cassegrain telescope design - or a refractive plastic system - either an acrylic or silicone-on-glass Fresnel lens - for concentration. Both systems have their advantages in areas of performance and durability. Both system designs manufacture their optics by low-cost processes that are unavailable to the other material system. These contrasts are reviewed. The refractive system embodies a simpler optical concept, requiring a single Fresnel lens rather than two concentrating mirrors. However, the reflective, glass system uses the greater design sophistication to provide a greater acceptance angle, which yields tolerance benefits in both manufacture and installation; and also provides faster optics without suffering the spectral aberrations of the refractive systems. Both glass and plastics are low-cost commodity materials. The long-term durability of optical glass is more firmly established than for optical plastics. And light transmission through optical plastics is attenuated by absorbance in both the UV and IR regions, in regions where such light is harvested by efficient multi-junction solar cells.

  3. Morphological and hemodynamic analysis of mirror posterior communicating artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Jinyu Xu

    Full Text Available BACKGROUND AND PURPOSE: Hemodynamic factors are commonly believed to play an important role in the pathogenesis, progression, and rupture of cerebral aneurysms. In this study, we aimed to identify significant hemodynamic and morphological parameters that discriminate intracranial aneurysm rupture status using 3-dimensional-angiography and computational fluid dynamics technology. MATERIALS AND METHODS: 3D-DSA was performed in 8 patients with mirror posterior communicating artery aneurysms (Pcom-MANs. Each pair was divided into ruptured and unruptured groups. Five morphological and three hemodynamic parameters were evaluated for significance with respect to rupture. RESULTS: The normalized mean wall shear stress (WSS of the aneurysm sac in the ruptured group was significantly lower than that in the unruptured group (0.52±0.20 versus 0.81±0.21, P = .012. The percentage of the low WSS area in the ruptured group was higher than that in the unruptured group (4.11±4.66% versus 0.02±0.06%, P = .018. The AR was 1.04±0.21 in the ruptured group, which was significantly higher than 0.70±0.17 in the unruptured group (P = .012. By contrast, parameters that had no significant differences between the two groups were OSI (P = .674, aneurysm size (P = .327, size ratio (P = .779, vessel angle (P = 1.000 and aneurysm inclination angle (P = 1.000. CONCLUSIONS: Pcom-MANs may be a useful disease model to investigate possible causes of aneurysm rupture. The ruptured aneurysms manifested lower WSS, higher percentage of low WSS area, and higher AR, compared with the unruptured one. And hemodynamics is as important as morphology in discriminating aneurysm rupture status.

  4. In vitro study on the anticoagulant effect of the water soluble contrast material: Diatrizoate, Ioxaglate and Iopromide

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Duk; Chin, Soo Yil [Korea Cancer Center Hospital, Seoul (Korea, Republic of); Kim, Hak Soo; Park, Jae Hyung [Seoul National University Hospital, Seoul (Korea, Republic of)

    1989-12-15

    It has been reported that newly developed nonionic contrast material is less effective in anticoagulation than ionic contrast media. Anticoagulation properties were studied with high osmolar ionic contrast medium (diatrizoate), low osmolar ionic medium (ioxaglate) and low osmolar nonionic contrast medium (iopromide) as well as with normal saline for control. Arterial blood was taken from 10 adults before angiography. Two ml. of the arterial blood was introduced into the plastic syringes containing 2 cc. of each contrast medium and saline . The syrings were kept undisturbed in room temperature for 10 minutes, 30 minutes, 60 minutes, 90 minutes and then the blood contrast mixture was poured on the filter paper to detect the clots formed in the syrings. Delay of the clotting time was also checked in the contrast media with various concentrations of 100%, 30%, 10%, and 3%. Chi-square test of the data shows very significant difference in anticoagulation effect between the ionic group (diatrizoate, ioxzglate) and the nonionic one (iopromide). Clotting time in the nonionic medium (iopromide) was shorter in 30% concentration than that of the ionic material (diatrizoate, ioxaglate). Nonionic contrast medium (iopromide) has anticoagulation effect, but less effective than ionic media (diatrizoate, ioxaglate)

  5. Contrast material and gallbladder kinetics: implications for same day sonography after intravenous pyelography or CT scanning.

    Science.gov (United States)

    Khan, O; Naipaul, R; Rampaul, R S; Abhang, V; Archibald, A; Maharaj, P; Mohammed, S; Mohammed, L

    1999-11-01

    Sonographic examination of the gallbladder has allowed us to study the effects of various substances on this organ. A prospective study involving 77 patients was undertaken to evaluate the effects of intravenous or oral contrast agents on gallbladder volume changes in patients without known gallbladder disease. A mean volume after contraction of 24.8% was observed after administration of intravenous contrast agent (P < 0.01) and of 31.9% after oral administration (P < 0.01). This phenomenon of contraction of the gallbladder should therefore be recognized when sonographic or computed tomographic evaluation of the gallbladder is undertaken after imaging procedures that use radiographic contrast agents either intravenously or orally.

  6. Hemodynamic Profiling in Complicated Pregnancies

    NARCIS (Netherlands)

    J.M.J. Cornette (Jérôme)

    2016-01-01

    textabstractIn order to permit a successful pregnancy outcome, the cardiovascular system must undergo substantial changes. This thesis addresses the hemodynamics in several pregnancy complications. A general overview of normal hemodynamic adaptation to pregnancy is provided . Several techniques of

  7. Obesity and renal hemodynamics

    NARCIS (Netherlands)

    Bosma, R. J.; Krikken, J. A.; van der Heide, J. J. Homan; de Jong, P. E.; Navis, G. J.

    2006-01-01

    Obesity is a risk factor for renal damage in native kidney disease and in renal transplant recipients. Obesity is associated with several renal risk factors such as hypertension and diabetes that may convey renal risk, but obesity is also associated with an unfavorable renal hemodynamic profile

  8. Obesity and renal hemodynamics

    NARCIS (Netherlands)

    Bosma, R. J.; Krikken, J. A.; van der Heide, J. J. Homan; de Jong, P. E.; Navis, G. J.

    2006-01-01

    Obesity is a risk factor for renal damage in native kidney disease and in renal transplant recipients. Obesity is associated with several renal risk factors such as hypertension and diabetes that may convey renal risk, but obesity is also associated with an unfavorable renal hemodynamic profile inde

  9. Cerebral hemodynamics in migraine

    DEFF Research Database (Denmark)

    Hachinski, V C; Olesen, Jes; Norris, J W

    1977-01-01

    Clinical and angiographic findings in migraine are briefly reviewed in relation to cerebral hemodynamic changes shown by regional cerebral blood flow (rCBF) studies. Three cases of migraine studied by the intracarotid xenon 133 method during attacks are reported. In classic migraine, with typical...

  10. Conditional-likelihood approach to material decomposition in spectral absorption-based or phase-contrast CT

    Science.gov (United States)

    Baturin, Pavlo

    2015-03-01

    Material decomposition in absorption-based X-ray CT imaging suffers certain inefficiencies when differentiating among soft tissue materials. To address this problem, decomposition techniques turn to spectral CT, which has gained popularity over the last few years. Although proven to be more effective, such techniques are primarily limited to the identification of contrast agents and soft and bone-like materials. In this work, we introduce a novel conditional likelihood, material-decomposition method capable of identifying any type of material objects scanned by spectral CT. The method takes advantage of the statistical independence of spectral data to assign likelihood values to each of the materials on a pixel-by-pixel basis. It results in likelihood images for each material, which can be further processed by setting certain conditions or thresholds, to yield a final material-diagnostic image. The method can also utilize phase-contrast CT (PCI) data, where measured absorption and phase-shift information can be treated as statistically independent datasets. In this method, the following cases were simulated: (i) single-scan PCI CT, (ii) spectral PCI CT, (iii) absorption-based spectral CT, and (iv) single-scan PCI CT with an added tumor mass. All cases were analyzed using a digital breast phantom; although, any other objects or materials could be used instead. As a result, all materials were identified, as expected, according to their assignment in the digital phantom. Materials with similar attenuation or phase-shift values (e.g., glandular tissue, skin, and tumor masses) were especially successfully when differentiated by the likelihood approach.

  11. Background interference on the color of dental composite materials with different thickness by digital contrast

    Science.gov (United States)

    Lins, Emery C.; Florez, Fernando L. E.; Portero, Priscila P.; Lizarelli, Rozane F. Z.; Oliveira, Osmir B., Jr.; Bagnato, Vanderlei S.

    2007-02-01

    In this work the color dependence of resin composites with the background color was evaluated. The objective was to measure since what thickness the color of the sample stops being influenced by the color of the background over which the resin is placed and the methodology used in experiment was based in analyzing the contrast of digital images of the sample over a black background. The results shown that since 0.8 mm the images contrast becomes almost constant; it prove that since this thickness the color of resin composite depends on the optical resin properties only. The experiment was repeated under three conditions of luminosity to evaluate the influence of it on the image contrast and the results obtained were identical.

  12. Nuclear fission as a tool to contrast the contraband of special nuclear material

    Indian Academy of Sciences (India)

    Viesti Giuseppe; Cester Davide; Nebbia Giancarlo; Stevanato Luca; Neri Francesco; Petrucci Stefano; Selmi Simone; Tintori Carlo

    2015-09-01

    An integrated mobile system for port security is presented. The system was designed to perform passive measurements of neutrons and -rays to search and identify radioactive and special nuclear materials as well as for the active investigations by using the tagged neutron inspection technique of suspect dangerous materials. The discrimination between difficult-to-detect uranium samples and high materials as lead was specifically studied. The system has been employed in laboratory detection tests and in a seaport field test.

  13. A Simplified Method for Upscaling Composite Materials with High Contrast of the Conductivity

    KAUST Repository

    Ewing, R.

    2009-01-01

    A large class of industrial composite materials, such as metal foams, fibrous glass materials, mineral wools, and the like, are widely used in insulation and advanced heat exchangers. These materials are characterized by a substantial difference between the thermal properties of the highly conductive materials (glass or metal) and the insulator (air) as well as low volume fractions and complex network-like structures of the highly conductive components. In this paper we address the important issue for the engineering practice of developing fast, reliable, and accurate methods for computing the macroscopic (upscaled) thermal conductivities of such materials. We assume that the materials have constant macroscopic thermal conductivity tensors, which can be obtained by upscaling techniques based on the postprocessing of a number of linearly independent solutions of the steady-state heat equation on representative elementary volumes (REVs). We propose, theoretically justify, and computationally study a numerical method for computing the effective conductivities of materials for which the ratio δ of low and high conductivities satisfies δ ≪ 1. We show that in this case one needs to solve the heat equation in the region occupied by the highly conductive media only. Further, we prove that under certain conditions on the microscale geometry the proposed method gives an approximation that is O(δ)-close to the upscaled conductivity. Finally, we illustrate the accuracy and the limitations of the method on a number of numerical examples. © 2009 Society for Industrial and Applied Mathematics.

  14. Heart function and hemodynamics

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930469 The effects of different ventricular pac-ing rates on cardiac hemodynamics and theirclinical significance.WEI Meng(魏盟),et al.Zhongshan Hosp,Shanghai Med Univ,Shanghai,200032.Shanghai Med J 1993;16(3):125—126.Changes of hemodynamics were investigated in26 patients at ventricular pacing rate of 60 to120,and 160 bpm.Effects of increasing ventricu-lar pacing rate on EF which were determined bygated blood pool scintigraphy were also studiedin another 11 patients.It is concluded that:1)inpatients with normal cardiac function as well asmost patients with cardiac insufficiency,the rela-tion of CO with increasing pacing rate can be il-

  15. Role and Effectiveness of Percutaneous Arterial Embolization in Hemodynamically Unstable Patients with Ruptured Splanchnic Artery Pseudoaneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Dohan, Anthony, E-mail: anthony.dohan@lrb.aphp.fr [Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, Department of Abdominal and Interventional Imaging (France); Eveno, Clarisse, E-mail: clarisse.eveno@lrb.aphp.fr [Université Paris-Diderot, Sorbonne Paris Cité (France); Dautry, Raphael, E-mail: raphael.dautry@lrb.aphp.fr; Guerrache, Youcef, E-mail: docyoucef05@yahoo.fr [Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, Department of Abdominal and Interventional Imaging (France); Camus, Marine, E-mail: marine.camus@lrb.aphp.fr [Université Paris-Diderot, Sorbonne Paris Cité (France); Boudiaf, Mourad, E-mail: mourad.boudiaf@lrb.aphp.fr [Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, Department of Abdominal and Interventional Imaging (France); Gayat, Etienne, E-mail: etienne.gayat@lrb.aphp.fr [Université Paris-Diderot, Sorbonne Paris Cité (France); Dref, Olivier Le, E-mail: olivier.ledref@lrb.aphp.fr; Sirol, Marc, E-mail: marc.sirol@lrb.aphp.fr; Soyer, Philippe, E-mail: philippe.soyer@lrb.aphp.fr [Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, Department of Abdominal and Interventional Imaging (France)

    2015-08-15

    PurposeTo assess the role and effectiveness of percutaneous arterial embolization (TAE) in patients with hemodynamic instability due to hypovolemic shock secondary to ruptured splanchnic artery pseudoaneurysms (SAPA).Materials and MethodsSeventeen patients (11 men, 6 women; mean age, 53 years) with hemodynamic instability (systolic blood pressure <90 mmHg) due to hypovolemic shock secondary to ruptured SAPA were treated by TAE. Clinical files, multidetector row computed tomography angiography, and angiographic examinations along with procedure details were reviewed.ResultsSeventeen SAPAs were present, predominantly located on gastroduodenal or pancreatic arteries (9/17; 53 %). Angiography showed extravasation of contrast medium from SAPA in 15/17 patients (88 %). Technical success rate of TAE was 100 %. TAE was performed using metallic coils in all patients (100 %), in association with gelatin sponge in 5/17 patients (29 %). TAE allowed controlling the bleeding and returning to normal hemodynamic status in 16/17 patients (94 %). In 1/17 patient (6 %), surgery was needed to definitively control the bleeding. The mortality and morbidity rate of TAE at 30 days were 0 and 12 %, respectively. Morbidity consisted in coil migration in 1/17 patient (6 %) and transient serum liver enzyme elevation in 1/17 patient (6 %).ConclusionTAE is an effective and safe treatment option for ruptured SAPA in hemodynamically unstable patients, with a success rate of 94 %. Our results suggest that TAE should be the favored option in patients with hemodynamic instability due to ruptured SAPA.

  16. Use of CO2 as an angiographic contrast material in the diagnosis of acute hepatic hemorrhage a case report; Uso del CO2 como medio de contraste angiografico en el diagnostico de hemorragia hepatica aguda: a proposito de un caso

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, L.; Gorriz, E.; Pardo, M. D.; Reyes, R. [Hospital General de Gran Canaria. Dr. Negrin. Canarias (Spain)

    2001-07-01

    Selective abdominal arteriography with an iodinated contrast material is the method of choice for detecting the site of bleeding in patients with acute gastrointestinal hemorrhage in whom the results of endoscopic examination were negative CO{sub 2}, has been used successfully as a contrast material for arteriography of abdomen and lower limbs. We present the case of a patient in whom suspected gastrointestinal bleeding was detected more rapidly and reliably with co{sub 2} than with an iodinated contrast material. (Author) 18 Refs.

  17. Material characterization of poly-lactic acid shelled ultrasound contrast agent and their dynamics

    Science.gov (United States)

    Paul, Shirshendu; Russakow, Daniel; Rodgers, Tyler; Sarkar, Kausik; Cochran, Michael; Wheatley, Margaret

    2011-11-01

    Micron-size gas bubbles encapsulated with lipids and proteins are used as contrast enhancing agents for ultrasound imaging. Biodegradable polymer poly-lactic acid (PLA) has recently been suggested as a possible means of encapsulation. Here, we report in vitro measurement of attenuation and scattering of ultrasound through an emulsion of PLA agent as well as theoretical modeling of the encapsulated bubble dynamics. The attenuation measured with three different transducers of central frequencies 2.25, 3.5 and 5 MHz, shows a peak around 2-3 MHz. These bubbles also show themselves to possess excellent scattering characteristics including strong non-linear response that can be used for harmonic and sub-harmonic contrast imaging. Our recently developed interfacial rheological models are applied to describe the dynamics of these bubbles; rheological model properties are estimated using measured attenuation data. The model is then applied to predict nonlinear scattered response, and the prediction is compared against experimental observation. Partially supported by NSF and NIH.

  18. Material híbrido como agente de contraste en imágenes de resonancia magnética

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2014-01-01

    La presente invención se refiere a un agente de contraste de resonancia magnética basado en un material híbrido compuesto de un núcleo órgano-metálico derivado del azul de Prusia y una cubierta de sílice y, opcionalmente, moléculas de un poli(etilenglicol), un agente fluorescente, un radionúcleo y/o una sustancia directora a receptores, células o tejidos específicos, unidas por enlace covalente a la superficie de la cubierta inorgánica.

  19. Material híbrido como agente de contraste en imágenes de resonancia magnética

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2014-01-01

    La presente invención se refiere a un agente de contraste de resonancia magnética basado en un material híbrido compuesto de un núcleo órgano-metálico derivado del azul de Prusia y una cubierta de sílice y, opcionalmente, moléculas de un poli(etilenglicol), un agente fluorescente, un radionúcleo y/o una sustancia directora a receptores, células o tejidos específicos, unidas por enlace covalente a la superficie de la cubierta inorgánica.

  20. How influential is the duration of contrast material bolus injection in perfusion CT? evaluation in a swine model.

    Science.gov (United States)

    Kandel, Sonja M; Meyer, Henning; Boehnert, Markus; Hoppel, Bernice; Paul, Narinder Singh; Rogalla, Patrik

    2014-01-01

    To analyze the effect of the duration of contrast material bolus injection on perfusion values in a swine model by using the maximum slope method. This study was approved by the institutional animal care committee. Twenty pigs (weight range, 63-77 kg) underwent dynamic volume computed tomography (CT) of the kidneys during suspended respiration. Before the CT examination, a miniature cuff-shaped ultrasonographic flow probe encircling the right renal artery was surgically implanted in each pig to obtain true perfusion values. Two sequential perfusion CT series were performed in 30 seconds, each comprising 30 volumes with identical parameters (100 kV, 200 mAs, 0.5 sec rotation time). The duration of contrast material bolus (0.5 mL/kg of body weight) was 3.8 seconds in the first series (short bolus series) and 11.5 seconds in the second series (long bolus series), and the injection flow rate was adapted accordingly. In each pig, cortical kidney volume was determined by using the volume with the highest cortical enhancement. CT perfusion values were calculated for both series by using the maximum slope method and were statistically compared and correlated with the true perfusion values from the flow probe by using linear regression analysis. Mean true perfusion and CT perfusion values (in minutes(-1)) for the short bolus series were 1.95 and 2.03, respectively (P = .22), and for the long bolus series, they were 2.02 and 1.92, respectively (P = .12). CT perfusion showed very good correlation with true perfusion in both the short (slope, 1.01; 95% confidence interval: 0.91, 1.11) and long (slope, 0.92; 95% confidence interval: 0.78, 1.04) series. On the basis of the regression analysis, CT perfusion values in the short bolus series were overestimated by 1% and those in the long bolus series were underestimated by 8%. Duration of contrast material bolus injection does not influence CT perfusion values substantially. The longer, clinically preferred intravenous injection

  1. Microscopic identification of Chinese medicinal materials based on X-ray phase contrast imaging: from qualitative to quantitative

    Science.gov (United States)

    Xue, Y.; Liang, Z.; Tan, H.; Ni, L.; Zhao, Z.; Xiao, T.; Xu, H.

    2016-07-01

    Although a variety of methods, ranging from simple morphological examination to physical and chemical analysis, and DNA molecular biology, exist for authenticating Chinese medicinal materials(CMMs), no methods can achieve both the source species identification and quality evaluation of CMMs simultaneously. Furthermore, the methods that are currently available for the identification of CMMs, including both optical and electronic microscopy, usually entail strict requirements for sample preparation or testing environment, such as the slicing of super-thin sections, or processing with specific chemical reagents. These treatments not only damage the CMMs but may also cause some of the original microstructures to be missed. Additionally, they may even yield false results. Owing to the unique penetrating character of X-rays, X-ray phase contrast imaging(XPCI) can be used to realize the inner microstructures of CMMs through nondestructive imaging. With the higher flux and luminance of the third generation of synchrotron radiation facility, XPCI can provides clearer and finer microstructures of CMMs, which are mainly composed of C, H, O, and N elements, with better spatial and density resolutions. For more than ten years, the X-ray imaging group at the Shanghai Institute of Applied Physics has investigated the microstructures of CMMs by XPCI and they have established and developed a quantitative X-ray phase contrast micro-CT for investigating the characteristic microstructures of CMMs. During this period, a variety of typical CMMs have been investigated, from two-dimensional (2D) radiography to three-dimensional (3D) micro-CT, from qualitative to quantitative. Taken together, these results verify that quantitative X-ray phase contrast micro-CT is a practical tool for the microscopic investigation of CMMs. Additionally, further efforts are being made to find the relationship between the microstructures' quantitative factors and active chemical components. At present

  2. True non-contact atomic force microscopy imaging of heterogeneous biological samples in liquids: topography and material contrast.

    Science.gov (United States)

    Almonte, Lisa; Colchero, Jaime

    2017-02-23

    The present work analyses how the tip-sample interaction signals critically determine the operation of an Atomic Force Microscope (AFM) set-up immersed in liquid. On heterogeneous samples, the conservative tip-sample interaction may vary significantly from point to point - in particular from attractive to repulsive - rendering correct feedback very challenging. Lipid membranes prepared on a mica substrate are analyzed as reference samples which are locally heterogeneous (material contrast). The AFM set-up is operated dynamically at low oscillation amplitude and all available experimental data signals - the normal force, as well as the amplitude and frequency - are recorded simultaneously. From the analysis of how the dissipation (oscillation amplitude) and the conservative interaction (normal force and resonance frequency) vary with the tip-sample distance we conclude that dissipation is the only appropriate feedback source for stable and correct topographic imaging. The normal force and phase then carry information about the sample composition ("chemical contrast"). Dynamic AFM allows imaging in a non-contact regime where essentially no forces are applied, rendering dynamic AFM a truly non-invasive technique.

  3. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading.

    Science.gov (United States)

    Hudspeth, M; Sun, T; Parab, N; Guo, Z; Fezzaa, K; Luo, S; Chen, W

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s(-1) and 5000 s(-1) strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imaged via phase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffraction via in-house software (WBXRD_GUI). Of current interest is the ability to evaluate crystal d-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates.

  4. Hygromorphic behaviour of cellular material: hysteretic swelling and shrinkage of wood probed by phase contrast X-ray tomography

    Science.gov (United States)

    Derome, Dominique; Rafsanjani, Ahmad; Patera, Alessandra; Guyer, Robert; Carmeliet, Jan

    2012-10-01

    Wood is a hygromorphic material, meaning it responds to changes in environmental humidity by changing its geometry. Its cellular biological structure swells during wetting and shrinks during drying. The origin of the moisture-induced deformation lies at the sub-cellular scale. The cell wall can be considered a composite material with stiff cellulose fibrils acting as reinforcement embedded in a hemicellulose/lignin matrix. The bulk of the cellulose fibrils, forming 50% of the cell wall, are oriented longitudinally, forming long-pitched helices. Both components of cell wall matrix are displaying swelling. Moisture sorption and, to a lesser degree, swelling/shrinkage are known to be hysteretic. We quantify the affine strains during the swelling and shrinkage using high resolution images obtained by phase contrast synchrotron X-ray tomography of wood samples of different porosities. The reversibility of the swelling/shrinkage is found for samples with controlled moisture sorption history. The deformation is more hysteretic for high than for low density samples. Swelling/shrinkage due to ad/desorption of water vapour displays also a non-affine component. The reversibility of the swelling/shrinkage indicates that the material has a structural capacity to show a persistent cellular geometry for a given moisture state and a structural composition that allows for moisture-induced transitional states. A collection of qualitative observations of small subsets of cells during swelling/shrinkage is further studied by simulating the observed behaviour. An anisotropic swelling coefficient of the cell wall is found to emerge and its origin is linked to the anisotropy of the cellulose fibrils arrangement in cell wall layers.

  5. Hemodynamics of hepatic focal nodular hyperplasia with contrast-enhanced ultrasonography%肝局灶性结节性增生的超声造影血流动力学研究

    Institute of Scientific and Technical Information of China (English)

    王文平; 范培丽; 魏瑞雪; 丁红; 黄备建; 季正标; 李超伦

    2010-01-01

    目的 探讨肝局灶性结节性增生的实时灰阶超声造影表现及其诊断价值.方法 对经手术病理证实的34例肝局灶性结节件增生(FNH)患者共36个病灶进行超声检查,观察病灶的常规超声表现和超声造影增强方式及表现并进行分析.结果 36个病灶多为低回声,39%(14/36)病灶周围见低回声环.65%(20/31)病灶内显示特征性的星状或轮辐状彩色血流.超声造影后动脉相观察到3种增强形式:整体型增强28%(10/36),泉涌状增强44%(16/36)和放射状增强28%(10/36).超声造影中搬痕出现率17%(6/36),而对照病理标本瘢痕检出率为40%(6/15).若以超声造影出现其中一种征象(泉涌状增强、放射状增强或瘢痕)作为FNH的诊断指标,则超声造影诊断FNH的符合率达78%(28/36),明显高于常规超声的诊断符合率(28%,10/36).结论 超声造影对诊断FNH有很大价值.%Objective To investigate enhancement appearance of hepatic focal nodular hyperplasia(FNH) at real-time gray-scale contrast enhanced ultrasonography(CEUS),and evaluate the value of CEUS in the diagnosis of FNH. Methods Thirty-four patients (36 lesions) with histologically proved FNH were examined by ultrasonography. Appearance on conventional ultrasonography and the enhancement pattern on CEUS were investigated. Results Thirty-six lesions were mostly hypoechoic.39% (14/36) of lesions had peripheral hypoechogenic circle. Color Doppler flow imaging showed a asteroid-like or spoke-and-wheel pattern in 65% (20/ 31) of lesions.Three enhancement patterns were observed in the early arterial phase: whole-enhancement pattern (28%, 10/36), gushing-spring enhancement pattern (44%, 16/36), and spoke-and-wheel enhancement pattern (28%,10/36).The frequency of central scar on CEUS was 17% (6/36), and detection rate of central scar by CEUS compared with pathology was 40% (6/15).Regarding one of the features (gushing-spring enhancement, spoke-and-wheel enhancement and scar) as standard of

  6. Vascular Profile Characterization of Liver Tumors by Magnetic Resonance Imaging Using Hemodynamic Response Imaging in Mice

    Directory of Open Access Journals (Sweden)

    Yifat Edrei

    2011-03-01

    Full Text Available Recently, we have demonstrated the feasibility of using hemodynamic response imaging (HRI, a functional magnetic resonance imaging (MRI method combined with hypercapnia and hyperoxia, for monitoring vascular changes during liver pathologies without the need of contrast material. In this study, we evaluated HRI ability to assess changes in liver tumor vasculature during tumor establishment, progression, and antiangiogenic therapy. Colorectal adenocarcinoma cells were injected intrasplenically to model colorectal liver metastasis (CRLM and the Mdr2 knockout mice were used to model primary hepatic tumors. Hepatic perfusion parameters were evaluated using the HRI protocol and were compared with contrast-enhanced (CE MRI. The hypovascularity and the increased arterial blood supply in well-defined CRLM were demonstrated by HRI. In CRLM-bearing mice, the entire liver perfusion was attenuated as the HRI maps were significantly reduced by 35%. This study demonstrates that the HRI method showed enhanced sensitivity for small CRLM (1–2 mm detection compared with CE-MRI (82% versus 38%, respectively. In addition, HRI could demonstrate the vasculature alteration during CRLM progression (arborized vessels, which was further confirmed by histology. Moreover, HRI revealed the vascular changes induced by rapamycin treatment. Finally, HRI facilitates primary hepatic tumor characterization with good correlation to the pathologic differentiation. The HRI method is highly sensitive to subtle hemodynamic changes induced by CRLM and, hence, can function as an imaging tool for understanding the hemodynamic changes occurring during CRLM establishment, progression, and antiangiogenic treatment. In addition, this method facilitated the differentiation between different types of hepatic lesions based on their vascular profile noninvasively.

  7. Does gadolinium-based contrast material improve diagnostic accuracy of local invasion in rectal cancer MRI? A multireader study.

    Science.gov (United States)

    Gollub, Marc J; Lakhman, Yulia; McGinty, Katrina; Weiser, Martin R; Sohn, Michael; Zheng, Junting; Shia, Jinru

    2015-02-01

    OBJECTIVE. The purpose of this study was to compare reader accuracy and agreement on rectal MRI with and without gadolinium administration in the detection of T4 rectal cancer. MATERIALS AND METHODS. In this study, two radiologists and one fellow independently interpreted all posttreatment MRI studies for patients with locally advanced or recurrent rectal cancer using unenhanced images alone or combined with contrast-enhanced images, with a minimum interval of 4 weeks. Readers evaluated involvement of surrounding structures on a 5-point scale and were blinded to pathology and disease stage. Sensitivity, specificity, negative predictive value, positive predictive value, and AUC were calculated and kappa statistics were used to describe interreader agreement. RESULTS. Seventy-two patients (38 men and 34 women) with a mean age of 61 years (range, 32-86 years) were evaluated. Fifteen patients had 32 organs invaded. Global AUCs without and with gadolinium administration were 0.79 and 0.77, 0.91 and 0.86, and 0.83 and 0.78 for readers 1, 2, and 3, respectively. AUCs before and after gadolinium administration were similar. Kappa values before and after gadolinium administration for pairs of readers ranged from 0.5 to 0.7. CONCLUSION. On the basis of pathology as a reference standard, the use of gadolinium during rectal MRI did not significantly improve radiologists' agreement or ability to detect T4 disease.

  8. Fe-C interactions and soil organic matter stability in two tropical soils of contrasting parent materials

    Science.gov (United States)

    Coward, E.; Thompson, A.; Plante, A. F.

    2014-12-01

    The long residence time of soil organic matter (SOM) is a dynamic property, reflecting the diversity of stabilization mechanisms active within the soil matrix. Climate and ecosystem properties act at the broadest scale, while biochemical recalcitrance, physical occlusion and mineral association drive stability at the microscale. Increasing evidence suggests that the stability of SOM is dominated by organo-mineral interactions. However, the 2:1 clays that provide much of the stabilization capacity in temperate soils are typically absent in tropical soils due to weathering. In contrast, these soils may contain an abundance of iron and aluminium oxides and oxyhydroxides, known as short-range-order (SRO) minerals. These SRO minerals are capable of SOM stabilization through adsorption or co-precipitation, a faculty largely enabled by their high specific surface area (SSA). As such, despite their relatively small mass, SRO minerals may contribute substantially to the SOM stabilization capacity of tropical soils. The objective of this work is to characterize and quantify these Fe-C interactions. Surface (0-20 cm) soil samples were taken from 20 quantitative soil pits dug within the Luquillo Critical Zone Observatory in northeast Puerto Rico. Soils were stratified across granodiorite and volcaniclastic parent materials. Four extraction procedures were used to isolate three different forms of Fe-C interactions: sodium pyrophosphate to isolate organo-metallic complexes, hydroxylamine and oxalate to isolate SRO Fe- and Al-hydroxides, and dithionite to isolate crystalline Fe-oxyhydroxides. Extracts were analysed for DOC and Fe and Al concentrations to estimate the amount of SOM associated with each mineral type. Soils were subjected to SSA and solid-phase C analyses before and after extraction to determine the contribution of the various Fe mineral types to soil SSA, and therefore to potential stabilization capacity through organo-mineral complexation. Preliminary results

  9. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Sales, Camila Pessoa; Carvalho, Heloisa de Andrade; Rubo, Rodrigo Augusto; Stuart, Silvia Radwanski; Rodrigues, Laura Natal, E-mail: camyps@gmail.com [Universidade de Sao Paulo (InRad/HC/FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Instituto de Radiologia; Taverna, Khallil Chaim; Pastorello, Bruno Fraccini [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Departamento de Radiologia e Oncologia. Lab. de Ressonancia Magnetica em Neurorradiologia; Borgonovi, Arthur Felipe [Royal Philips Electronics, Eindhoven (Netherlands)

    2016-05-15

    Objective: to identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and methods: magnetic resonance images were acquired with six different catheter-filling materials - water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO{sub 4}) water solution (2.08 g/L) - inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO{sub 4}. The best contrast media were tested in four patients with the applicators in place. Results: in T2-weighted sequences, the best contrast was achieved with the CuSO{sub 4}-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO{sub 4} presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion: we found CuSO{sub 4} to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position. (author)

  10. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies*

    Science.gov (United States)

    Sales, Camila Pessoa; Carvalho, Heloisa de Andrade; Taverna, Khallil Chaim; Pastorello, Bruno Fraccini; Rubo, Rodrigo Augusto; Borgonovi, Arthur Felipe; Stuart, Silvia Radwanski; Rodrigues, Laura Natal

    2016-01-01

    Objective To identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and Methods Magnetic resonance images were acquired with six different catheter-filling materials-water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO4) water solution (2.08 g/L)-inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO4. The best contrast media were tested in four patients with the applicators in place. Results In T2-weighted sequences, the best contrast was achieved with the CuSO4-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO4 presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion We found CuSO4 to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position. PMID:27403016

  11. Influence of barium sulfate X-ray imaging contrast material on properties of floating drug delivery tablets.

    Science.gov (United States)

    Diós, Péter; Szigeti, Krisztián; Budán, Ferenc; Pócsik, Márta; Veres, Dániel S; Máthé, Domokos; Pál, Szilárd; Dévay, Attila; Nagy, Sándor

    2016-12-01

    The objective of the study was to reveal the influence of necessarily added barium sulfate (BaSO4) X-ray contrast material on floating drug delivery tablets. Based on literature survey, a chosen floating tablet composition was determined containing HPMC and carbopol 943P as matrix polymers. One-factor factorial design with five levels was created for evaluation of BaSO4 (X1) effects on experimental parameters of tablets including: floating lag time, total floating time, swelling-, erosion-, dissolution-, release kinetics parameters and X-ray detected volume changes of tablets. Applied concentrations of BaSO4 were between 0 and 20.0% resulting in remarkable alteration of experimental parameters related especially to flotation. Drastic deterioration of floating lag time and total floating time could be observed above 15.0% BaSO4. Furthermore, BaSO4 showed to increase the integrity of tablet matrix by reducing eroding properties. A novel evaluation of dissolutions from floating drug delivery systems was introduced, which could assess the quantity of drug dissolved from dosage form in floating state. In the cases of tablets containing 20.0% BaSO4, only the 40% of total API amount could be dissolved in floating state. In vitro fine resolution X-ray CT imagings were performed to study the volume change and the voxel distributions as a function of HU attenuations by histogram analysis of the images. X-ray detected relative volume change results did not show significant difference between samples. After 24h, all tablets containing BaSO4 could be segmented, which highlighted the fact that enough BaSO4 remained in the tablets for their identification. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Effect of different ultrasound contrast materials and temperatures on patient comfort during intrauterine and tubal assessment for infertility

    Energy Technology Data Exchange (ETDEWEB)

    Fenzl, Vanja, E-mail: vanja.radic@inet.hr [Department of Gynecology and Obstetrics, University Hospital “Merkur”, Zajčeva 19 (Croatia); University of Applied Health Studies, Mlinarska Cesta 38, 10000 Zagreb (Croatia)

    2012-12-15

    Hysterosalpingo-contrast sonography (HyCoSy) is safe and easy to perform outpatient method in the evaluation of female infertility. During this procedure a certain level of discomfort and pain are experienced by patients. On the basis of reducing avoidable pain inductors the aim of this study was to compare pain sensation due to different warmth of applied contrasts (sterile saline and Echovist{sup ®}). Prospective and randomized study was performed on patients requiring tubal and uterine assessment during standard infertility work up. One group of patients was examined using both contrasts at room temperature and the other group using preheated contrasts at body temperature. Pain experience of the procedure was rated by patients for each contrast by numerical scale (0–10) immediately after the procedure. There was significant statistical difference between pain scores during application of two contrasts in each group; Echovist induces significantly less pain in comparison to sterile saline at the same temperature (P = 0.002, 0.001). Between two groups there is also statistically significant difference in pain during introduction of the same contrast at different temperature (P < 0.001). The most tolerable for the patient is body temperature of the applied contrasts although their structure and concentrations can be another factor associated with tolerability of the procedure.

  13. Risk of intravenous contrast material-mediated acute kidney injury: a propensity score-matched study stratified by baseline-estimated glomerular filtration rate.

    Science.gov (United States)

    McDonald, Jennifer S; McDonald, Robert J; Carter, Rickey E; Katzberg, Richard W; Kallmes, David F; Williamson, Eric E

    2014-04-01

    To determine the effect of baseline estimated glomerular filtration rate (eGFR) on the causal association between intravenous iodinated contrast material exposure and subsequent development of acute kidney injury (AKI) in propensity score-matched groups of patients who underwent contrast material-enhanced or unenhanced computed tomography (CT). This retrospective study was HIPAA compliant and institutional review board approved. All patients who underwent contrast-enhanced (contrast material group) or unenhanced (non-contrast material group) CT between 2000 and 2010 were identified and stratified according to baseline eGFR by using Kidney Disease Outcomes Quality Initiative cutoffs for chronic kidney disease into subgroups with eGFR of 90 or greater, 60-89, 30-59, and less than 30 mL/min/1.73 m(2). Propensity score generation and 1:1 matching of patients were performed in each eGFR subgroup. Incidence of AKI (serum creatinine [SCr] increase of ≥0.5 mg/dL [≥44.2 μmol/L] above baseline) was compared in the matched subgroups by using the Fisher exact test. A total of 12 508 propensity score-matched patients with contrast-enhanced and unenhanced scans met all inclusion criteria. In this predominantly inpatient cohort, the incidence of AKI significantly increased with decreasing baseline eGFR (P material and non-contrast material groups in any eGFR subgroup; for the subgroup with eGFR of 90 or greater (n = 1642), odds ratio (OR) was 0.91 (95% confidence interval [CI]: 0.38, 2.15), P = .82; for the subgroup with eGFR of 60-89 (n = 3870), OR was 1.03 (95% CI: 0.66, 1.60), P = .99; for the subgroup with eGFR of 30-59 (n = 5510), OR was 0.94 (95% CI: 0.76, 1.18), P = .65; and for the subgroup with eGFR of less than 30 mL/min/1.73 m(2) (n = 1486), OR was 0.97 (95% CI: 0.72, 1.30), P = .89. Diminished eGFR is associated with an increased risk of SCr-defined AKI following CT examinations. However, the risk of AKI is independent of contrast material exposure, even in

  14. Patient selection and preparation strategies for the use of contrast material in patients with chronic kidney disease

    DEFF Research Database (Denmark)

    Andersen, Poul Erik

    2012-01-01

    The prevalence of chronic kidney disease and peripheral arterial disease is increasing. Thus, it is increasingly problematic to image these patients as the number of patients needing a vascular examination is increasing accordingly. In high-risk patients with impaired kidney function, intravascular...... administration of iodinated contrast media can result in contrast-induced acute kidney injury and Gadolinium can induce nephrogenic systemic fibrosis (NSF). It is important to identify these high-risk patients by means of se-creatinine/e glomerular filtration rate. The indication for contrast examination should...

  15. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  16. Pulmonary 64-MDCT angiography with 50 mL of iodinated contrast material in an unselected patient population: a feasible protocol

    Energy Technology Data Exchange (ETDEWEB)

    Trad, Henrique Simao; Boasquevisque, Gustavo Santos; Giacometti, Tiago Rangon; Trad, Catherine Yang; Zoghbi Neto, Orlando Salomao; Trad, Clovis Simao, E-mail: hsimtrad@gmail.com [Central de Diagnostico Ribeirao Preto (CEDIRP), Ribeirao Preto, SP (Brazil)

    2016-03-15

    Objective: To propose a protocol for pulmonary angiography using 64-slice multidetector computed tomography (64-MDCT) with 50 mL of iodinated contrast material, in an unselected patient population, as well as to evaluate vascular enhancement and image quality. Materials and methods: We evaluated 29 patients (22-86 years of age). The body mass index ranged from 19.0 kg/m{sup 2} to 41.8 kg/m{sup 2}. Patients underwent pulmonary CT angiography in a 64-MDCT scanner, receiving 50 mL of iodinated contrast material via venous access at a rate of 4.5 mL/s. Bolus tracking was applied in the superior vena cava. Two experienced radiologists assessed image quality and vascular enhancement. Results: The mean density was 382 Hounsfield units (HU) for the pulmonary trunk; 379 and 377 HU for the right and left main pulmonary arteries, respectively; and 346 and 364 HU for the right and left inferior pulmonary arteries, respectively. In all patients, subsegmental arteries were analyzed. There were streak artifacts from contrast material in the superior vena cava in all patients. However, those artifacts did not impair the image analysis. Conclusion: Our findings suggest that pulmonary angiography using 64-MDCT with 50 mL of iodinated contrast can produce high quality images in unselected patient populations. (author)

  17. Pulmonary 64-MDCT angiography with 50 mL of iodinated contrast material in an unselected patient population: a feasible protocol*

    Science.gov (United States)

    Trad, Henrique Simão; Boasquevisque, Gustavo Santos; Giacometti, Tiago Rangon; Trad, Catherine Yang; Zoghbi Neto, Orlando Salomão; Trad, Clovis Simão

    2016-01-01

    Objective To propose a protocol for pulmonary angiography using 64-slice multidetector computed tomography (64-MDCT) with 50 mL of iodinated contrast material, in an unselected patient population, as well as to evaluate vascular enhancement and image quality. Materials and Methods We evaluated 29 patients (22-86 years of age). The body mass index ranged from 19.0 kg/m2 to 41.8 kg/m2. Patients underwent pulmonary CT angiography in a 64-MDCT scanner, receiving 50 mL of iodinated contrast material via venous access at a rate of 4.5 mL/s. Bolus tracking was applied in the superior vena cava. Two experienced radiologists assessed image quality and vascular enhancement. Results The mean density was 382 Hounsfield units (HU) for the pulmonary trunk; 379 and 377 HU for the right and left main pulmonary arteries, respectively; and 346 and 364 HU for the right and left inferior pulmonary arteries, respectively. In all patients, subsegmental arteries were analyzed. There were streak artifacts from contrast material in the superior vena cava in all patients. However, those artifacts did not impair the image analysis. Conclusion Our findings suggest that pulmonary angiography using 64-MDCT with 50 mL of iodinated contrast can produce high quality images in unselected patient populations. PMID:27141128

  18. Spiral CT and optimization of the modalities of the iodinated intravenous contrast material: Experimental studies in human pathology; Tomodensitometrie spiralee et optimisation des protocoles d'injection du contraste iode intra-veineux: etudes experimentales en pathologie humaine

    Energy Technology Data Exchange (ETDEWEB)

    Bonaldi, V

    1998-06-19

    Spiral (or helical) CT represents the most recent improvement in the field of computed assisted tomography (CAT scan). The capabilities of this new imaging modality are much superior to these of conventional CT scanning; then result from the rapid acquisition and from the volumetric nature of the derived data set. The short time of data acquisition had made mandatory the revision of protocols for intravenous administration of iodinated contrast material. By the means of several studies, carried out on pathologic and healthy patients, we have attempted to improve knowledge in factors influencing CT attenuation values after injection of contrast material, in the aim of improving contrast administration performed during spiral CT scanning. Anatomical landmarks that we have studied till now have been liver, the pancreas, the kidney and the cervical spine. In addition, a paired based methodology has been used. The volumetric set of data derived from spiral CT scanning leads to optimal post-processing tasks, the most interesting being related to cine-display and multiplanar reformatting; both modalities have been evaluated, about the pancreas and the musculo-skeletal system respectively. Conversely, this new modality, as for other imaging modalities, is responsible for additional costs derived from restless increase in the number of images to be dealt with and from the occurrence of new tasks (in post-processing particularly). The place of spiral CT in diagnostic strategies among other modern imaging modalities should be assessed, especially with respect to Magnetic Resonance Imaging (MRI). (author)

  19. Feasibility of 320-row area detector CT coronary angiography using 40 mL of contrast material: assessment of image quality and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Rihyeon; Park, Eun-Ah; Lee, Whal; Chung, Jin Wook [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2016-11-15

    To assess the image quality and diagnostic accuracy of 320-row area detector CT (320-ADCT) coronary angiography using 40 mL of contrast material in comparison with 60-mL protocol. This retrospective study included 183 patients who underwent 320-ADCT coronary angiography using 40 mL of contrast and additional 183 sex- and body mass index-matched patients using 60 mL of contrast constituting the control group. Both groups used the same 5-mL/sec injection rate. Quantitative image quality measurements and diagnostic accuracies were calculated and compared. Mean attenuation and contrast-to-noise ratio (CNR) at the aorta and all coronary arteries were lower in the 40-mL group than in the 60-mL group (all, p < 0.05), except for the CNR at proximal coronary arteries at 100 kVp (p = 0.073). However, the proportion of coronary segments with vessel attenuation >250 HU was not different between groups (all, p > 0.05), except for distal coronary arteries at 80 kVp (p = 0.001). Furthermore, there were no differences in per-patient and per-segment diagnostic accuracies between the groups (all, p > 0.05). 320-ADCT coronary angiography using 40 mL of contrast showed image quality and diagnostic accuracy comparable to the 60-mL protocol, demonstrating the clinical feasibility of lowering the risk of contrast-induced nephropathy through contrast volume reduction. (orig.)

  20. Effects of radiation on tumor hemodynamics and NF-kappaB in breast tumors

    Science.gov (United States)

    Stantz, Keith M.; Cao, Ning; Liu, Bo; Cao, Minsong; Chin-Sinex, Helen; Mendonca, Marc; Li, Jian Jian

    2010-02-01

    Purpose: The purpose of this study is to monitor in vivo the IR dose dependent response of NF-κB and tumor hemodynamics as a function of time. Material and Methods: An MDA-231 breast cancer cell line was stably transfected with a firefly luciferase gene within the NF-kappaB promoter. Tumors on the right flank irradiated with a single fractionated dose of 5Gy or 10Gy. Over two weeks, photoacoustic spectroscopy (PCT-S), bioluminescence imaging (BLI), and dynamic contrast enhanced CT (DCE-CT) was used to monitor hemoglobin status, NF-kappaB expression, and physiology, respectively. Results: From the BLI, an increase in NF-kappaB expression was observed in both the right (irradiation) and left (nonirradiated) tumors, which peaked at 8-12 hours, returned to basal levels after 24 hours, and increased a second time from 3 to 7 days. This data identifies both a radiation-induced bystander effect and a bimodal longitudinal response associated with NF-κB-controlled luciferase promoter. The physiological results from DCE-CT measured an increase in perfusion (26%) two days after radiation and both a decrease in perfusion and an increase in fp by week 1 (10Gy cohort). PCT-S measured increased levels of oxygen saturation two days post IR, which did not change after 1 week. Initially, NF-κB would modify hemodynamics to increase oxygen delivery after IR insult. The secondary response appears to modulate tumor angiogenesis. Conclusions: A bimodal response to radiation was detected with NF-kappaB-controlled luciferase reporter with a concomitant hemodynamic response associated with tumor hypoxia. Experiments are being performed to increase statistics.

  1. [Investigation of characteristic microstructures of adhesive interface in wood/bamboo composite material by synchrotron radiation X-ray phase contrast microscopy].

    Science.gov (United States)

    Peng, Guan-Yun; Wang, Yu-Rong; Ren, Hai-Qing; Yang, Shu-Min; Ma, Hong-Xia; Xie, Hong-Lan; Deng, Biao; Du, Guo-Hao; Xiao, Ti-Qiao

    2013-03-01

    Third-generation synchrotron radiation X-ray phase-contrast microscopy(XPCM)can be used for obtaining image with edge enhancement, and achieve the high contrast imaging of low-Z materials with the spatial coherence peculiarity of X-rays. In the present paper, the characteristic microstructures of adhesive at the interface and their penetration in wood/bamboo composite material were investigated systematically by XPCM at Shanghai Synchrotron Radiation Facility (SSRF). And the effect of several processing techniques was analyzed for the adhesive penetration in wood/bamboo materials. The results show that the synchrotron radiation XPCM is expected to be one of the important precision detection methods for wood-based panels.

  2. Effect of Fixed-Volume and Weight-Based Dosing Regimens on the Cost and Volume of Administered Iodinated Contrast Material at Abdominal CT.

    Science.gov (United States)

    Davenport, Matthew S; Parikh, Kushal R; Mayo-Smith, William W; Israel, Gary M; Brown, Richard K J; Ellis, James H

    2017-03-01

    To determine the magnitude of subject-level and population-level cost savings that could be realized by moving from fixed-volume low-osmolality iodinated contrast material administration to an effective weight-based dosing regimen for contrast-enhanced abdominopelvic CT. HIPAA-compliant, institutional review board-exempt retrospective cohort study of 6,737 subjects undergoing contrast-enhanced abdominopelvic CT from 2014 to 2015. Subject height, weight, lean body weight (LBW), and body surface area (BSA) were determined. Twenty-six volume- and weight-based dosing strategies with literature support were compared with a fixed-volume strategy used at the study institution: 125 mL 300 mgI/mL for routine CT, 125 mL 370 mgI/mL for multiphasic CT (single-energy, 120 kVp). The predicted population- and subject-level effects on cost and contrast material utilization were calculated for each strategy and sensitivity analyses were performed. Most subjects underwent routine CT (91% [6,127/6,737]). Converting to lesser-volume higher-concentration contrast material had the greatest effect on cost; a fixed-volume 100 mL 370 mgI/mL strategy resulted in $132,577 in population-level savings with preserved iodine dose at routine CT (37,500 versus 37,000 mgI). All weight-based iodine-content dosing strategies (mgI/kg) with the same maximum contrast material volume (125 mL) were predicted to contribute mean savings compared with the existing fixed-volume algorithm ($4,053-$116,076/strategy in the overall study population, $1-$17/strategy per patient). Similar trends were observed in all sensitivity analyses. Large cost and material savings can be realized at abdominopelvic CT by adopting a weight-based dosing strategy and lowering the maximum volume of administered contrast material. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  3. On the origin of differential phase contrast at a locally charged and globally charge-compensated domain boundary in a polar-ordered material

    Energy Technology Data Exchange (ETDEWEB)

    MacLaren, Ian; Wang, LiQiu; McGrouther, Damien; Craven, Alan J.; McVitie, Stephen [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Schierholz, Roland [Institute of Energy and Climate Research: Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich, 52425 Jülich (Germany); Kovács, András [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen (Germany); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)

    2015-07-15

    Differential phase contrast (DPC) imaging in the scanning transmission electron microscope is applied to the study of a charged antiphase domain boundary in doped bismuth ferrite. A clear differential signal is seen, which matches the expected direction of the electric field at the boundary. However, further study by scanned diffraction reveals that there is no measurable deflection of the primary diffraction disc and hence no significant free E-field in the material. Instead, the DPC signal arises from a modulation of the intensity profile within the primary diffraction disc in the vicinity of the boundary. Simulations are used to show that this modulation arises purely from the local change in crystallographic structure at the boundary and not from an electric field. This study highlights the care that is required when interpreting signals recorded from ferroelectric materials using both DPC imaging and other phase contrast techniques. - Highlights: • We show clear differential phase contrast (DPC) at a charged boundary. • Scanning diffraction shows that the discs do not move. • Disc deflection by electric fields is not the source of the DPC signal. • Diffraction contrast within the disc is the source of the DPC signal. • DPC and holography of E fields is difficult due to diffraction contrast.

  4. Bolus tracking with nanofilter-based multispectral videography for capturing microvasculature hemodynamics

    Science.gov (United States)

    Najiminaini, Mohamadreza; Kaminska, Bozena; St. Lawrence, Keith; Carson, Jeffrey J. L.

    2014-04-01

    Multispectral imaging is a highly desirable modality for material-based analysis in diverse areas such as food production and processing, satellite-based reconnaissance, and biomedical imaging. Here, we present nanofilter-based multispectral videography (nMSV) in the 700 to 950 nm range made possible by the tunable extraordinary-optical-transmission properties of 3D metallic nanostructures. Measurements made with nMSV during a bolus injection of an intravascular tracer in the ear of a piglet resulted in spectral videos of the microvasculature. Analysis of the multispectral videos generated contrast measurements representative of arterial pulsation, the distribution of microvascular transit times, as well as a separation of the venous and arterial signals arising from within the tissue. Therefore, nMSV is capable of acquiring serial multispectral images relevant to tissue hemodynamics, which may have application to the detection and identification of skin cancer.

  5. Hemodynamic gestational adaptation in bitches

    OpenAIRE

    Vívian Tavares de Almeida; Ricardo Andres Ramirez Uscategui; Priscila Del Aguila da Silva; Michele Lopes Avante; Ana Paula Rodrigues Simões; Wilter Ricardo Russiano Vicente

    2017-01-01

    ABSTRACT: Throughout pregnancy, maternal hemodynamic adaptation is needed to ensure proper uterine perfusion and fetal development. When the uteroplacental vascular system is formed, starting with reduced resistance to uterine arterial flow, this results in decreased total vascular resistance, an activation of neuroendocrine vasoactive peptides, an increase in circulating blood and changes in the cardiovascular system morphophysiology to respond to the increasing demands of uterine perfusion....

  6. Hemodynamic gestational adaptation in bitches

    Directory of Open Access Journals (Sweden)

    Vívian Tavares de Almeida

    Full Text Available ABSTRACT: Throughout pregnancy, maternal hemodynamic adaptation is needed to ensure proper uterine perfusion and fetal development. When the uteroplacental vascular system is formed, starting with reduced resistance to uterine arterial flow, this results in decreased total vascular resistance, an activation of neuroendocrine vasoactive peptides, an increase in circulating blood and changes in the cardiovascular system morphophysiology to respond to the increasing demands of uterine perfusion. There has been considerable study of hemodynamic adaptation in pregnant women and this assessment has become a diagnostic tool for fatal obstetric disorders. However, in bitches the available information in this regard is limited; therefore a parallel was drawn between other species of animals and women, in order to subsidize the paucity of information about this process and facilitate the understanding of maternal-fetal hemodynamic adaptation in pregnant bitches. This review and literature analysis aimed\\ to discuss morphophysiological cardiovascular adaptations during pregnancy and the possible disorders that can affect this process in pregnant female dogs.

  7. Influences of prolonged apnea and oxygen inhalation on pulmonary hemodynamics during breath holding: Quantitative assessment by velocity-encoded MR imaging with SENSE technique

    Energy Technology Data Exchange (ETDEWEB)

    Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)], E-mail: aznogami@med.kobe-u.ac.jp; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Higashino, Takanori [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Department of Radiology, Tenri Hospital, Tenri, Nara (Japan); Takenaka, Daisuke [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Yoshikawa, Takeshi [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Department of Radiology, Konan Hospital, Kobe, Hyogo (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Kawamitsu, Hideaki [Division of Radiology, Kobe University Hospital, Kobe, Hyogo (Japan); Fujii, Masahiko [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Radiology, Kobe University Hospital, Kobe, Hyogo (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)

    2007-12-15

    Purpose: The purpose of our study was to assess the influence of prolonged apnea and administration of oxygen on pulmonary hemodynamics during breath holding (BH) by using velocity-encoded MR imaging combined with the SENSE technique (velocity MRI). Materials and methods: Ten healthy male volunteers underwent velocity MRI during BH with and without O{sub 2} inhalation. All velocity MRI data sets were obtained continuously with the 2D cine phase-contrast method during a single BH period. The data were then divided into three BH time phases as follows: first, second and third. To evaluate the influence of prolonged apnea on hemodynamics, stroke volume (SV) and maximal change in flow rate during ejection (MCFR) of second and third phases were statistically compared with those of first phase by using the ANOVA followed by Turkey's HSD multiple comparison test. To assess the influence of O{sub 2} on hemodynamics, SV and MCFR with or without O{sub 2} were compared by the paired t-test. To assess the measuring agreement of hemodynamic indices during prolonged breath holding, Bland-Altman's analysis was performed. Results: Prolonged apnea had no significant influence on SV and MCFR regardless of administration of O{sub 2} (p > 0.05). Mean MCFR for all phases was significantly lower with administration of O{sub 2} than without (p < 0.05). The limits of agreement for MCFR with O{sub 2} were smaller than without. Conclusion: O{sub 2} inhalation modulated maximal change in flow rate during ejection, and did not influence stroke volume during breath holding. Influence of O{sub 2} inhalation should be considered for MR measurements of pulmonary hemodynamics during breath holding.

  8. Material characterization of the encapsulation of an ultrasound contrast microbubble and its subharmonic response: strain-softening interfacial elasticity model.

    Science.gov (United States)

    Paul, Shirshendu; Katiyar, Amit; Sarkar, Kausik; Chatterjee, Dhiman; Shi, William T; Forsberg, Flemming

    2010-06-01

    Two nonlinear interfacial elasticity models--interfacial elasticity decreasing linearly and exponentially with area fraction--are developed for the encapsulation of contrast microbubbles. The strain softening (decreasing elasticity) results from the decreasing association between the constitutive molecules of the encapsulation. The models are used to find the characteristic properties (surface tension, interfacial elasticity, interfacial viscosity and nonlinear elasticity parameters) for a commercial contrast agent. Properties are found using the ultrasound attenuation measured through a suspension of contrast agent. Dynamics of the resulting models are simulated, compared with other existing models and discussed. Imposing non-negativity on the effective surface tension (the encapsulation experiences no net compressive stress) shows "compression-only" behavior. The exponential and the quadratic (linearly varying elasticity) models result in similar behaviors. The validity of the models is investigated by comparing their predictions of the scattered nonlinear response for the contrast agent at higher excitations against experimental measurement. All models predict well the scattered fundamental response. The nonlinear strain softening included in the proposed elastic models of the encapsulation improves their ability to predict subharmonic response. They predict the threshold excitation for the initiation of subharmonic response and its subsequent saturation.

  9. Beam hardening and smoothing correction effects on performance of micro-ct SkyScan 1173 for imaging low contrast density materials

    Energy Technology Data Exchange (ETDEWEB)

    Sriwayu, Wa Ode [Physics Departement, Haluoleo University Indonesia (Indonesia); Haryanto, Freddy; Khotimah, Siti Nurul; Latief, Fourier Dzar Eljabbar [Physics Departement, ITB Indonesia email : ayoe-fisika@yahoo.com (Indonesia)

    2015-04-16

    We have designed and fabricated phantom mimicking breast cancer composition known as a region that has low contrast density. The used compositions are a microcalcifications, fatty tissues and tumor mass by using Al{sub 2}O{sub 3}, C{sub 27}H{sub 46}O, and hard nylon materials. Besides, phantom also has a part to calculate low cost criteria /CNR (Contrast to Noise Ratio). Uniformity will be measured at water distillation medium located in a part of phantom scale contrast. Phantom will be imaged by using micro ct-sky scan 1173 high energy type, and then also can be quantified CT number to examine SkyScan 1173 performance in imaging low contrast density materials. Evaluation of CT number is done at technique configuration parameter using voltage of 30 kV, exposure 0.160 mAs, and camera resolution 560x560 pixel, the effect of image quality to reconstruction process is evaluated by varying image processing parameters in the form of beam hardening corrections with amount of 25%, 66% and100% with each smoothing level S10,S2 and S7. To obtain the better high quality image, the adjustment of beam hardening correction should be 66% and smoothing level reach maximal value at level 10.

  10. Flat-detector computed tomography with intravenous contrast material application in experimental aneurysms: comparison with multislice CT and conventional angiography.

    Science.gov (United States)

    Struffert, Tobias; Doelken, Marc; Adamek, Edyta; Schwarz, Marc; Engelhorn, Tobias; Kloska, Stephan; Ott, Sabine; Doerfler, Arnd

    2010-05-01

    Despite limited soft tissue resolution flat-detector computed tomography (FD-CT) provides substantial superior spatial resolution in comparison with multislice computed tomography (MS-CT). This may add value in the visualization of small vascular structures if intravenous contrast application leads to substantial opacification and visibility of intracranial vessels or aneurysms. To evaluate the feasibility of visualization of vascular structures by FD-CT angiography (FD-CTA) after intravenous contrast injection compared with MS-CTA and intra-arterial digital subtracted angiography (IADSA) in an animal model. Aneurysms were created in the right common carotid artery in six New Zealand White Rabbits using the elastase technique. Imaging was performed using FD-CTA, MS-CTA (injection of 1 ml/kg body weight) and IADSA. Anonymized volume rendering reconstruction (VRT), maximum intensity projection (MIP), and multiplanar reconstruction (MPR) images were reconstructed and evaluated by two experienced reviewers for aneurysm geometry and vascular structure anatomy using standard tools of a dedicated workstation. Aneurysms could be successfully created in all animals. Measurements of aneurysm geometry (aneurysm height, width, neck width) and vascular structures (brachiocephalic trunk, carotid artery diameter and plane) were nearly identical in all three modalities. Intra- and inter-observer correlations of the different parameters showed high r values between 0.83 and 0.99. Our results show the feasibility of FD-CTA in comparison with MS-CTA and IADSA in an animal model. Despite limited soft tissue resolution, opacification of vascular structures with sufficient contrast to the surrounding structures was possible in all animals. Vascular structures appeared better delineated in FD-CTA than in MS-CTA, probably due to the superior spatial resolution.

  11. Assessment of hemodynamic parameters of uterus during physiological pregnancy

    OpenAIRE

    Chekhonatskaya M.L.; Petrosyan N.O.

    2015-01-01

    The aim of the article is to analysis of the hemodynamic parameters of the uterus and cervix during the second and third trimesters of pregnancy. Material and methods. It was conducted dynamic ultrasound in 240 women with physiological course for singleton pregnancies in the period from 12 weeks of gestation until term labor. Results. For the second trimester of pregnancy redistribution of total uterine blood flow in the direction of increasing blood flow in more of the body than the cervix h...

  12. Country of origin effects in developed and emerging markets: Exploring the contrasting roles of materialism and value consciousness

    OpenAIRE

    Piyush Sharma

    2011-01-01

    Despite growing evidence about differences in the attitudes and behaviors of consumers in emerging and developed markets, there is little research on the differences in country of origin (COO) effects on their evaluation, behavioral intentions (BIs), and actual purchase of imported products. This paper introduces a new conceptual framework incorporating consumer ethnocentrism (CET), materialism (MAT), and value consciousness (VC) to hypothesize several differences in the influence of COO effe...

  13. [Physiopathology of nephropathy studied with contrast media].

    Science.gov (United States)

    Morales Buenrostro, L E; Tellez Zenteno, J F; Torre Delgadillo, A

    2000-01-01

    For the technological advances in diagnostic and therapeutic procedures, the use of intravenous contrast media in the hospital is more and more frequent. It can produce acute renal failure secondary to its nephrotoxicity known as contrast media nephropathy. This review describes the pathophysiologic mechanisms of contrast media injury, including cytotoxicity caused by hyperosmoloarity of contrast media, the hemodynamic factors and the role of the renin-angiotensin system, prostaglandins, oxygen free radicals, endothelin-1, adenosine, nitric oxide and others. The understanding of this information is of vital importance for the development of prophylactic strategies for contrast media nephropathy.

  14. Wind sorting affects differently the organo-mineral composition of saltating and particulate materials in contrasting texture agricultural soils

    Science.gov (United States)

    Iturri, Laura Antonela; Funk, Roger; Leue, Martin; Sommer, Michael; Buschiazzo, Daniel Eduardo

    2017-10-01

    There is little information about the mineral and organic composition of sediments eroded by wind at different heights. Because of that, wind tunnel simulations were performed on four agricultural loess soils of different granulometry and their saltating materials collected at different heights. The particulate matter with an aerodynamic diameter mainly smaller than 10 μm (PM10) of these soils was obtained separately by a laboratory method. Results indicated that the granulometric composition of sediments collected at different heights was more homogeneous in fine- than in sandy-textured soils, which were more affected by sorting effects during wind erosion. This agrees with the preferential transport of quartz at low heights and of clay minerals at greater heights. SOC contents increased with height, but the composition of the organic materials was different: stable carboxylic acids, aldehydes, amides and aromatics were preferentially transported close to the ground because their were found in larger aggregates, while plant debris and polysaccharides, carbohydrates and derivatives of microbial origin from organic matter dominated at greater heights for all soil types. The amount of SOC in the PM10 fraction was higher when it was emitted from sandy than from fine textured soils. Because of the sorting process produced by wind erosion, the stable organic matter compounds will be transported at low heights and local scales, modifying soil fertility due to nutrient exportation, while less stable organic compounds will be part of the suspension losses, which are known to affect some processes at regional- or global scale.

  15. Utility of Functional Hemodynamics and Echocardiography to Aid Diagnosis and Management of Shock.

    Science.gov (United States)

    McGee, William T; Raghunathan, Karthik; Adler, Adam C

    2015-12-01

    The utility of functional hemodynamics and bedside ultrasonography is increasingly recognized as advantageous for both improved diagnosis and management of shock states. In contrast to conventional "static" measures, "dynamic" hemodynamic measures and bedside imaging modalities enhance pathophysiology-based comprehensive understanding of shock states and the response to therapy. The current editions of major textbooks in the primary specialties--in which clinicians routinely encounter patients in shock--including surgery, anesthesia, emergency medicine, and internal medicine continue to incorporate traditional (conventional) descriptions of shock that use well-described (but potentially misleading) intravascular pressures to classify shock states. Reliance on such intravascular pressure measurements is not as helpful as newer "dynamic" functional measures including ultrasonography to both better assess volume responsiveness and biventricular cardiac function. This review thus emphasizes the application of current functional hemodynamics and ultrasonography to the diagnosis and management of shock as a contrast to conventional "static" pressure-based measures.

  16. Effect of radiologic contrast material on cell volume regulation in proximal renal tubules from trout (Salmo trutta).

    Science.gov (United States)

    Galtung, H K; Løken, M; Sakariassen, K S

    2000-11-01

    Most radiographic contrast media (CM) are hyperosmotic and pose an osmotic threat to cells they are in contact with. To study these effects at the cellular level, cell volume regulatory mechanisms were observed in proximal renal tubules following exposure to the CM iohexol, ioxaglate, and iodixanol. Isolated renal tubules from trout (Salmo trutta) were exposed to 5% vol/vol iohexol (326 mOsm), ioxaglate (314 mOsm), or iodixanol (300 mOsm) or mannitol (to achieve the same osmolalities), and cell volume changes were observed videometrically. Iohexol and ioxaglate solutions induced a rapid shrinkage (12%-13%) not followed by cell volume regulation. Without CM (same osmolality), the cells shrank 11% but then showed a 77%-88% volume recovery. This reswelling was inhibited by 55% with the Na+, K+, Cl- symporter inhibitor bumetanide (50 micromol/L). Iodixanol did not significantly affect cell volume. Tubules preincubated with CM or mannitol were then stimulated with a hypoosmotic Ringer solution (160 mOsm) resulting in a 26%-36% cellular volume increase. Compared with results of experiments without mannitol and CM, preexposure to iohexol or ioxaglate almost completely inhibited the expected regulatory shrinkage phase, while previous exposure to hyperosmotic solutions with mannitol reduced the shrinkage response by 40%-53%. In this system, the hyperosmotic iohexol and ioxaglate cause cell shrinkage followed by an impaired cell volume regulatory response. Exposure to these two CM also inhibits cell volume regulation on hypoosmotic stimulation. The isosmotic iodixanol has no such effects. These changes appear to some extent to be a result of the CM's degree of hyperosmolality, but this property alone does not explain these findings.

  17. Detection of liver metastases: usefulness of dynamic spiral CT during the portal phase with a higher IV injection rate of contrast material

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Youn Sin; Cho, June Sik; Youn, Wan Gyu; Ahn, Young Jun; Choi, Chang Lak; Lee, Young Hwan [Chungnam National Univ. College of Medicine, Taejon (Korea, Republic of)

    1996-07-01

    To evaluate the usefulness of dynamic spiral computed tomography(CT) during the portal phase with a higher IV injection rate of contrast material in detecting hepatic metastases. We reviewed two-phase dynamic spiral CT in 44 patients with hepatic metastases of pathologically proven primary malignancy. One hundred and fifty ml. of non-ionic contrast material was administered with a power injector at a rate of 5ml/sec., and two-phase images at 55-80 sec.(portal phase) and 2-5min. (equilibrium phase) were obtained after the start of bolus injection. Two phase images were compared for detectability of hepatic metastases according to size, number and enhancement pattern. In cases of metastases less than 1 cm, 113 lesions(100%) that showed clearly defined hypodense lesions were detected in the portal phase of dynamic CT. However, the equilibrium phase images showed hypodense lesions in 58 cases(51%) and isodense lesions in 55 cases(49%). In cases of metastases 1-2cm in size, the portal phase images detected 70 hypodense lesions(92%) and six hyperdense lesions(8%). In the equilibrium phase, however, the lesions were hypodense in 54 cases(71%), hyperdense in four(5%), and isodense in 18(24%). In cases of metastases larger than 2cm, portal phase images showed 29 hypodense lesions(97%) and one hyperdense lesion(3%). In the equilibrium phase, however, the lesions were hypodense in 25 cases(83%), hyperdense in two(7%), and mixed in three(10%). As compared with the portal phase, most metastatic lesions were detected as poorly defined hypodense or isodense lesions in the equilibrium phase and decrease in size due to peripheral enahncement. Dynamic spiral CT during the portal phase with a higher IV injection rate(5ml/sec) of contrast material is a useful method for detecting hepatic metastases, especially small lesions less than 1cm.

  18. Multiplanar spiral CT enterography in patients with Crohn's disease using a negative oral contrast material: initial results of a noninvasive imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Reittner, Pia; Goritschnig, Toria; Doerfler, Otto [Department of Radiology, Karl Franzens Medical School and University Hospital Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Petritsch, Wolfgang; Hinterleitner, Thomas [Department of Internal Medicine, Karl Franzens Medical School and University Hospital Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Preidler, Klaus W.; Szolar, Dieter H. [Diagnostikum Graz Sued West, Weblinger Guertel 25, 8054 Graz (Austria)

    2002-09-01

    The aim of this study was to prospectively define the role of multiplanar spiral CT enterography with a new negative oral contrast material for noninvasive assessment of the small bowel in patients with Crohn's disease. Thirty patients with established Crohn's disease prospectively underwent spiral CT enterography at 45-60 min after distension of the small bowel with 1400 ml of a negative oral contrast material (Mucofalk water enema). Spiral CT scans were obtained 50 s after administration of intravenous contrast material with the following parameters: 5-mm collimation; 7.5-mm/s table feed; and 3-mm reconstruction interval. The adequacy of bowel opacification, luminal distension, and the contribution of two-dimensional multiplanar reformatted imaging were assessed by two observers. Spiral CT imaging findings were compared with results of enteroclysis as well as endoscopic and histological findings in all patients. Spiral CT enterography with Mucofalk water enema was well tolerated in 29 of 30 patients. Findings on spiral CT enterography were comparable with those of barium studies in 25 of 30 patients, superior to those on barium studies in 4 patients, and inferior in 1 patient (p<0.05). The addition of multiplanar reformatted images to axial spiral CT scans significantly improved observers' confidence in image interpretation (p<0.05) but did not reveal additional abnormalities. Multiplanar spiral CT enterography with Mucofalk excellently provides information in patients with Crohn's disease. This technique accurately depicts the level of small bowel obstruction and the extent of inflammatory small bowel disease and its extraluminal complications. (orig.)

  19. Assessment of hemodynamic parameters of uterus during physiological pregnancy

    Directory of Open Access Journals (Sweden)

    Chekhonatskaya M.L.

    2015-06-01

    Full Text Available The aim of the article is to analysis of the hemodynamic parameters of the uterus and cervix during the second and third trimesters of pregnancy. Material and methods. It was conducted dynamic ultrasound in 240 women with physiological course for singleton pregnancies in the period from 12 weeks of gestation until term labor. Results. For the second trimester of pregnancy redistribution of total uterine blood flow in the direction of increasing blood flow in more of the body than the cervix has been considered to be typical. From the third trimester of pregnancy until term labor a significant increase of blood supply to the cervix has been found; there has been a tendency to increase the capacity of the vascular channel and the reduction in peripheral resistance vessels of cervix. Conclusions. Early detection of disorders of uterine and cervical hemodynamics allows to predict the occurrence of various pathological conditions.

  20. [CLINICAL-HEMODYNAMIC PECULIARITIES OF THE COURSE OF HEMODYNAMIC ISCHEMIC STROKE IN ACUTE PERIOD].

    Science.gov (United States)

    Shkrobot, S; Sokhor, N; Milevska-Vovchuk, L; Yasniy, O; Shkrobot, L

    2017-02-01

    The aim of the research is to study the peculiarities of cardiac morphometric parameters, the parameters of central hemodynamics and their impact on the course of hemodynamic ischemic stroke in acute period. 116 patients were performed Echo-Doppler-cardiography in acute period of hemodynamic ischemic stroke in order to evaluate cardiac morphometric parameters. These patients were also performed transcranial duplex scanning. The results established that among significant clinical factors that influence the course of the acute period of hemodynamic ischemic stroke the most important are: the size of the focus, the level of consciousness on the 1st day, primary systolic arterial pressure, age of the patient. Hemodynamic ischemic stroke occurs on the background of changes of cardiac morphometric parameters and the disorders of the central hemodynamics. There is a close connection between the severity of hemodynamic ischemic stroke on the 7th and 14th day with the ejection fraction, the size of left atrium, the thickness of posterior wall of left ventricle, final diastolic size of left ventricle. The interrelation between the parameters of cerebral hemodynamics and cardiac morphometric parameters was established. cardiac morphometric parameters and parameters of central hemodynamics can be predictors of the course of hemodynamic ischemic stroke in acute period.

  1. Endogenous nitric oxide synthase inhibitors, arterial hemodynamics, and subclinical vascular disease: the PREVENCION Study.

    Science.gov (United States)

    Chirinos, Julio A; David, Robert; Bralley, J Alexander; Zea-Díaz, Humberto; Muñoz-Atahualpa, Edgar; Corrales-Medina, Fernando; Cuba-Bustinza, Carolina; Chirinos-Pacheco, Julio; Medina-Lezama, Josefina

    2008-12-01

    Endogenous NO synthase inhibitors (end-NOSIs) have been associated with cardiovascular risk factors and atherosclerosis. In addition, end-NOSIs may directly cause hypertension through hemodynamic effects. We aimed to examine the association between end-NOSI asymmetrical dimethylarginine (ADMA) and N-guanidino-monomethyl-arginine (NMMA), subclinical atherosclerosis, and arterial hemodynamics. We studied 922 adults participating in a population-based study (PREVENCION Study) and examined the correlation between end-NOSI/L-arginine and arterial hemodynamics, carotid-femoral pulse wave velocity, and carotid intima-media thickness using linear regression. ADMA, NMMA, and L-arginine were found to be differentially associated with various classic cardiovascular risk factors. ADMA and NMMA (but not L-arginine) were significant predictors of carotid intima-media thickness, even after adjustment for cardiovascular risk factors, C-reactive protein, and renal function. In contrast, ADMA and NMMA did not predict carotid-femoral pulse wave velocity, blood pressure, or hemodynamic abnormalities. Higher L-arginine independently predicted systolic hypertension, higher central pulse pressure, incident wave amplitude, central augmented pressure, and lower total arterial compliance but not systemic vascular resistance or cardiac output. We conclude that ADMA and NMMA are differentially associated with cardiovascular risk factors, but both end-NOSIs are independent predictors of carotid atherosclerosis. In contrast, they are not associated with large artery stiffness, hypertension, or hemodynamic abnormalities. Our findings are consistent with a role for asymmetrical arginine methylation in atherosclerosis but not in large artery stiffening, hypertension, or long-term hemodynamic regulation. L-arginine is independently associated with abnormal pulsatile (but not resistive) arterial hemodynamic indices, which may reflect abnormal L-arginine transport, leading to decreased intracellular

  2. Multislice CT scans in patients on extracorporeal membrane oxygenation: Emphasis on hemodynamic changes and imaging pitfalls

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kao Lang; Wang, Yu Feng; Chang, Yeun Chung; Huang, Shu Chien; Chen, Shyh Jye; Chang, Chin Chen [National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei (China); Tsang, Yuk Ming [Dept. of Medical Imaging, Far Eastern Memorial Hospital, New Taipei City (China)

    2014-06-15

    This pictorial review provides the principles of extracorporeal membrane oxygenation (ECMO) support and associated CT imaging features with emphasis on the hemodynamic changes and possible imaging pitfalls encountered. It is important that radiologists in ECMO centers apply well-designed imaging protocols and familiarize themselves with post-contrast CT imaging findings in patients on ECMO.

  3. Safety and feasibility in highly concentrated contrast material power injections for CT-perfusion studies of the brain using central venous catheters

    Energy Technology Data Exchange (ETDEWEB)

    Macht, Stephan, E-mail: stephan.macht@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf (Germany); Beseoglu, Kerim, E-mail: beseoglu@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Neurosurgery, D-40225 Dusseldorf (Germany); Eicker, Sven, E-mail: sven.eicker@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Neurosurgery, D-40225 Dusseldorf (Germany); Rybacki, Konrad, E-mail: rybacki@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf (Germany); Braun, Sebastian, E-mail: sebastian.braun@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Anaesthesiology, D-40225 Dusseldorf (Germany); Mathys, Christian, E-mail: mathys@uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf (Germany); Antoch, Gerald, E-mail: antoch@med.uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf (Germany); Turowski, Bernd, E-mail: bernd.turowski@uni-duesseldorf.de [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf (Germany)

    2012-08-15

    Introduction: CT perfusion studies play an important role in the early detection as well as in therapy monitoring of vasospasm after subarachnoid hemorrhage. High-flow injections via central venous catheters are not recommended but may sometimes be the only possibility to obtain high-quality images. Materials and methods: We retrospectively analyzed our data for CT perfusions performed with power injection of contrast material with an iodine concentration of 400 mg/ml via the distal 16G lumen of the Arrow three and five lumen central venous catheter with preset flow rates of 5 ml/s. Results: 104 examinations with central venous catheters were evaluated (67 with five lumen and 37 with three lumen). No complications were observed. Mean flow rates were 4.4 {+-} 0.5 ml/s using the three lumen catheter and 4.6 {+-} 0.6 ml/s using the five lumen catheter respectively. The mean injection pressure measured by the power injector was 200.7 {+-} 17.5 psi for the three lumen central venous catheter and 194.5 {+-} 6.5 psi for the five lumen catheter, respectively. Conclusion: Following a strict safety protocol there were no complications associated with power injections of contrast material containing 400 mg iodine/ml with preset flow rates up to 5 ml/s via the distal 16G lumen of the Arrow multi-lumen central venous catheter. However, since power-injections are off-label use with Arrow central venous catheters, this procedure cannot be recommended until potential safety hazards have been ruled out by the manufacturer.

  4. Intravenous Contrast Material Administration at High-pitch Dual-source CT Coronary Angiography: Bolus-tracking Technique with Shortened Time of Respiratory Instruction Versus Test Bolus Technique

    Institute of Scientific and Technical Information of China (English)

    Kai Sun; Guo-rong Liu; Yue-chun Li; Rui-juan Han; Li-fang Cui; Li-jun Ma; Li-gang Li; Chang-yong Li

    2012-01-01

    Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique.Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study.The patients were randomly divided into two groups.Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode),while those in the group B (n=92) underwent CCTA with test bolus technique.The attenuation in the ascending aorta,image noise,contrast-to-noise ratio and radiation doses of the two groups were assessed.Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs.498.7±83.51 HU,P=0.183),image noise (21.4±4.5 HU vs.20.9±4.3 HU,P=0.414),contrast-to-noise ratio (12.1±4.2 vs.13.8±5.1,P=0.31) between the groups A and B.There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs.0.062±0.018 mSv,P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs.0.96±0.15 mSv,P=0.926) between the two groups,while 15 mL less contrast material volume was administered in the group A than the group B.Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.

  5. Immunologic, hemodynamic, and adrenal incompetence in cirrhosis

    DEFF Research Database (Denmark)

    Risør, Louise Madeleine; Bendtsen, Flemming; Møller, Søren

    2015-01-01

    dysfunction, but is not responsive to volume expansion. Recent research indicates that development of hepatic nephropathy represents a continuous spectrum of functional and structural dysfunction and may be precipitated by the inherent immunologic, adrenal, and hemodynamic incompetence in cirrhosis. New...... research explores several new markers of renal dysfunction that may replace serum creatinine in the future and give new insight on the hepatic nephropathy. Our understanding of the pathophysiological mechanisms causing the immunologic, adrenal, and hemodynamic incompetence, and the impact on renal...

  6. Effect of iptakalim hydrochloride on hemodynamics

    Institute of Scientific and Technical Information of China (English)

    Qing-leiZHU; HaiWANG; Wen-binXIAO

    2004-01-01

    AIM: To study the effect of iptakalim hydrochloride (Ipt) on hemodynamics. METHODS: Effect of Ipt on hemodynamics were studied in anesthetized nomotensive dogs, conscious nomotensive rats (NTR), and stroke prone spontaneously hypertensive rats (SHRsp), respectively. RESULTS: In pentobarbital anesthetized nomotensive dogs, Ipt at doses of 0.125, 0.25, 0.5,1.0, and 2.0 mg/kg iv could dose-dependently decrease blood pressure (BP), with the decrease of systolic BP equivalent

  7. Central Hemodynamics and Microcirculation in Critical Conditions

    Directory of Open Access Journals (Sweden)

    A. A. Kosovskikh

    2013-01-01

    Full Text Available Objective: to compare central hemodynamic and microcirculatory changes in critical conditions caused by different factors and to reveal their possible differences for a further differentiated approach to intensive therapy. Subjects and methods. The study covered 16 subjects with severe concomitant injury (mean age 41.96±2.83 years and 19 patients with general purulent peritonitis (mean age 45.34±2.16 years. Their follow-up was 7 days. The central hemodynamics was estimated by transpulmonary thermodilution using a Pulsion PiCCO Plus system (Pulsion Medical Systems, Germany. The microcirculatory bed was evaluated by cutaneous laser Doppler flowmetry using a LAKK-02 capillary blood flow laser analyzer (LAZMA Research-and-Production Association, Russian Federation. Results. The pattern of central hemodynamic and microcirculatory disorders varies with the trigger that has led to a critical condition. Central hemodynamics should be stabilized to ensure the average level of tissue perfusion in victims with severe concomitant injury. In general purulent peritonitis, microcirculatory disorders may persist even if the macrohemodynamic parameters are normal. Conclusion. The macrohemodynamic and microcirculatory differences obtained during the study suggest that a complex of intensive therapy should be differentiated and, if the latter is used, it is necessary not only to be based on the central hemodynamics, but also to take into consideration functional changes in microcirculation. Key words: severe concomitant injury, general purulent peritonitis, micro-circulation, central hemodynamics, type of circulation.

  8. Hemodynamic changes in depressive patients

    Institute of Scientific and Technical Information of China (English)

    MA Ying; LI Hui-chun; ZHENG Lei-lei; YU Hua-liang

    2006-01-01

    Objective: This study is aimed at exploring the relationship between hemodynamic changes and depressive and anxious symptom in depression patients. Methods: The cardiac function indices including the left stroke index (LSI), ejection fraction (EF), heart rate (HR), diastolic pressure mean (DPM), systolic pressure mean (SPM), left ventricle end-diastolic volume (LVDV), effective circulating volume (ECV), resistance total mean (RTM) and blood flow smooth degree (BFSD) were determined in 65 patients with major depressive disorders and 31 healthy normal controls. The clinical symptoms were assessed with Hamilton depression scale (HAMD) and Hamilton anxiety scale (HAMA). Results: In patients with depression without anxiety,LSI, EF, LVDV, DPM, SPM, ECV, BFSD were significantly lower than those in controls, while RTM was higher than that in controls. Patients with comorbidity of depression and anxiety showed decreased LVDV, ECV, BFSD, and increased HR in comparison with the controls. The anxiety/somatization factor score positively correlated with LSI, EF, LVDV, but negatively correlated with RTM. There was negative correlation between retardation factor score and DPM, SPM, LVDV. Conclusion: The study indicated that there are noticeable changes in left ventricle preload and afterload, blood pressure, peripheral resistance, and microcirculation in depressive patients, and that the accompanying anxiety makes the changes more complicated.

  9. Venous hemodynamic changes in lower limb venous disease: the UIP consensus according to scientific evidence.

    Science.gov (United States)

    Lee, Byung B; Nicolaides, Andrew N; Myers, Kenneth; Meissner, Mark; Kalodiki, Evi; Allegra, Claudio; Antignani, Pier L; Bækgaard, Niels; Beach, Kirk; Belcaro, Giovanni; Black, Stephen; Blomgren, Lena; Bouskela, Eliete; Cappelli, Massimo; Caprini, Joseph; Carpentier, Patrick; Cavezzi, Attilio; Chastanet, Sylvain; Christenson, Jan T; Christopoulos, Demetris; Clarke, Heather; Davies, Alun; Demaeseneer, Marianne; Eklöf, Bo; Ermini, Stefano; Fernández, Fidel; Franceschi, Claude; Gasparis, Antonios; Geroulakos, George; Gianesini, Sergio; Giannoukas, Athanasios; Gloviczki, Peter; Huang, Ying; Ibegbuna, Veronica; Kakkos, Stavros K; Kistner, Robert; Kölbel, Tilo; Kurstjens, Ralph L; Labropoulos, Nicos; Laredo, James; Lattimer, Christopher R; Lugli, Marzia; Lurie, Fedor; Maleti, Oscar; Markovic, Jovan; Mendoza, Erika; Monedero, Javier L; Moneta, Gregory; Moore, Hayley; Morrison, Nick; Mosti, Giovanni; Nelzén, Olle; Obermayer, Alfred; Ogawa, Tomohiro; Parsi, Kurosh; Partsch, Hugo; Passariello, Fausto; Perrin, Michel L; Pittaluga, Paul; Raju, Seshadri; Ricci, Stefano; Rosales, Antonio; Scuderi, Angelo; Slagsvold, Carl E; Thurin, Anders; Urbanek, Tomasz; M VAN Rij, Andre; Vasquez, Michael; Wittens, Cees H; Zamboni, Paolo; Zimmet, Steven; Ezpeleta, Santiago Z

    2016-06-01

    thrombosis indicating their pathophysiological and clinical significance. Chapter 3 describes the hemodynamic changes that occur in different classes of chronic venous disease and their relation to the anatomic extent of disease in the macrocirculation and microcirculation. The next four chapters (Chapters 4-7) describe the hemodynamic changes resulting from treatmen by compression using different materials, intermittent compression devices, pharmacological agents and finally surgical or endovenous ablation. Chapter 8 discusses the unique hemodynamic features associated with alternative treatment techniques used by the CHIVA and ASVAL. Chapter 9 describes the hemodynamic effects following treatment to relieve pelvic reflux and obstruction. Finally, Chapter 10 demonstrates that contrary to general belief there is a moderate to good correlation between certain hemodynamic measurements and clinical severity of chronic venous disease. The authors believe that this document will be a timely asset to both clinicians and researchers alike. It is directed towards surgeons and physicians who are anxious to incorporate the conclusions of research into their daily practice. It is also directed to postgraduate trainees, vascular technologists and bioengineers, particularly to help them understand the hemodynamic background to pathophysiology, investigations and treatment of patients with venous disorders. Hopefully it will be a platform for those who would like to embark on new research in the field of venous disease.

  10. Contrastive Lexicology.

    Science.gov (United States)

    Hartmann, R. R. K.

    This paper deals with the relation between etymologically related words in different languages. A survey is made of seven stages in the development of contrastive lexicology. These are: prelinguistic word studies, semantics, lexicography, translation, foreign language learning, bilingualism, and finally contrastive analysis. Concerning contrastive…

  11. Mode size converter between high-index-contrast waveguide and cleaved single mode fiber using SiON as intermediate material.

    Science.gov (United States)

    Jia, Lianxi; Song, Junfeng; Liow, Tsung-Yang; Luo, Xianshu; Tu, Xiaoguang; Fang, Qing; Koh, Sing-Chee; Yu, Mingbin; Lo, Guoqiang

    2014-09-22

    High-index-contrast (HIC) waveguide such as Si and Si3N4 has small mode size enabling compact integration. However, the coupling loss with single mode fiber is also remarkable owning to the mode mismatching. Therefore, mode size converter, as the interface between HIC waveguide and optical fiber, takes an important role in the field of integrated optics. The material with refractive index (RI) between HIC waveguide and optical fiber can be used as a bridge to reduce the mode mismatching loss. In this letter, we employ silicon oxynitride (SiON) with RI about 1.50 as the intermediate material and optimize the structure of the SiON waveguide to match with cleaved single mode fiber and HIC waveguide separately. Combined with inverse taper and suspended structure, the mismatching loss is reduced and the dependence to the dimension of the structure is also released. The coupling loss is 1.2 and 1.4 dB/facet for TE and TM mode, respectively, with 3 dB alignment tolerance of ± 3.5 μm for Si(3)N(4) waveguide with just 200 nm-wide tip. While for Si waveguide, a critical dimension of 150 nm is applied due to the higher index contrast than Si(3)N(4) waveguide. Similar alignment tolerance is realized with coupling loss about 1.8 and 2.1 dB/facet for TE and TM mode. The polarization dependence loss (PDL) for both platforms is within 0.5 dB.

  12. Differences in estimates of size distribution of beryllium powder materials using phase contrast microscopy, scanning electron microscopy, and liquid suspension counter techniques

    Directory of Open Access Journals (Sweden)

    Day Gregory A

    2007-02-01

    Full Text Available Abstract Accurate characterization of the physicochemical properties of aerosols generated for inhalation toxicology studies is essential for obtaining meaningful results. Great emphasis must also be placed on characterizing particle properties of materials as administered in inhalation studies. Thus, research is needed to identify a suite of techniques capable of characterizing the multiple particle properties (i.e., size, mass, surface area, number of a material that may influence toxicity. The purpose of this study was to characterize the morphology and investigate the size distribution of a model toxicant, beryllium. Beryllium metal, oxides, and alloy particles were aerodynamically size-separated using an aerosol cyclone, imaged dry using scanning electron microscopy (SEM, then characterized using phase contrast microscopy (PCM, a liquid suspension particle counter (LPC, and computer-controlled SEM (CCSEM. Beryllium metal powder was compact with smaller sub-micrometer size particles attached to the surface of larger particles, whereas the beryllium oxides and alloy particles were clusters of primary particles. As expected, the geometric mean (GM diameter of metal powder determined using PCM decreased with aerodynamic size, but when suspended in liquid for LPC or CCSEM analysis, the GM diameter decreased by a factor of two (p

  13. Contrast-to-noise ratio with different settings in a CBCT machine in presence of different root-end filling materials: an in vitro study.

    Science.gov (United States)

    Demirturk Kocasarac, Husniye; Helvacioglu Yigit, Dilek; Bechara, Boulos; Sinanoglu, Alper; Noujeim, Marcel

    2016-01-01

    To compare the contrast-to-noise ratio (CNR) of multiple acquisition settings for four types of retrograde filling materials in CBCT images taken for endodontic surgery follow-up. 20 maxillary central incisors were endodontically treated and obturated with 4 different root-end filling materials: amalgam, mineral trioxide aggregate, SuperEBA(™) (Harry J Bosworth Company, Skokie, IL) and Biodentine™ (Septodont, Saint-Maur-des-Faussés, France). Teeth were placed in a skull and scanned, one by one, with the Planmeca ProMax(®) 3D Max (Planmeca, Helsinki, Finland); at different voltages: 66, 76, 84 and 96 kVp; with low, normal and high resolution and high definition (HD); with and without metal artefact reduction (MAR). Images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the CNR. The dose-area product was registered, and the effective dose calculated. No statistically significant difference was noted between the four materials. 84 and 96 kVp with low resolution and the use of MAR-generated images that have statistically better CNR than 66 and 76 kVp with HD, normal and high resolutions and without MAR. The use of low resolution also generated the smallest value of effective dose. The best setting for radiographic follow-up in an endodontic surgery with retrograde filling on the Planmeca ProMax is 96 kVp with low resolution and high MAR; this setting produced one of the lowest effective doses.

  14. Hemodynamic Disorders in Severe Brain Injury

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2006-01-01

    Full Text Available This study was undertaken to determine the general regularities of hemodynamic disorders in relation to the severity of brain damage for the subsequent development of pathogenetically warranted methods for their correction in the complex of intensive care for severe brain injury. Studies were made in 67 victims, by using neurophysiological studies (electroencephalography, studies of acoustical stem-evoked potentials and somatosensory stem-evoked potentials, computed tomography and magnetic resonance imaging. Central hemodynamics was studied by a Sirecust 1260 monitoring system using Swan-Ganz catheters and thermodilution. The overall condition of the victims was regarded as very bad. Loss of consciousness was 8-4 scores by the Glasgow coma scale. The studies have indicated that the victims in whose clinical picture the signs of compression of the cerebral hemispheres dominate over those of the latter’s contusion develop a hemodynamic reaction by the normodynamic type. The hyperdynamic type of hemodynamic disorder develops in cerebral hemispheric and diencephalic lesions with a parallel increase in oxygen transport and uptake; and in severe brain injury, lower brain stem damages are accompanied by hemodynamic disorder by the hypodynamic type with a reduction in oxygen transport and uptake.

  15. Indexes of hemodynamics in a dosage of physical activity in girls against the background of low systolic blood pressure

    OpenAIRE

    Levchenko V. A.

    2015-01-01

    Purpose: to examine the state of hemodynamics, blood oxygenation levels in girls with hypotensive type neurodystonia in a dosed physical load. Material : The study involved 59 women with hypotensive type neurodystonia aged 18-19 years and 14 healthy women the same age. Results : It was found that the girls on the background of low systolic blood pressure observed early hemodynamic response from the very first steps (25-50 W) bicycle stress test in the form of increased heart rate, stroke volu...

  16. Hemodynamic stress response during laparoscopic cholecystectomy: Effect of two different doses of intravenous clonidine premedication

    Directory of Open Access Journals (Sweden)

    Deepshikha C Tripathi

    2011-01-01

    Full Text Available Background : Clonidine has emerged as an attractive premedication desirable in laparoscopic surgery wherein significant hemodynamic stress response is seen. The minimum safe and effective dose of intravenous clonidine to attenuate the hemodynamic stress response during laparoscopic surgery has however not yet been determined. Materials and Methods : This prospective, randomized, double-blind controlled study was conducted on 90 adults of ASA physical status I and II, scheduled for laparoscopic cholecystectomy under general anesthesia. Patients were randomized to one of the three groups (n= 30. Group I received 100 ml of normal saline, while groups II and III received 1 μg/ kg and 2 μg/ kg of clonidine respectively, intravenous, in 100 ml of normal saline along. All patients received glycopyrrolate 0.004 mg/kg and tramadol 1.5 mg/kg intravenously, 30 min before induction. Hemodynamic variables (heart rate, systolic, diastolic, mean arterial pressure, SpO2, and sedation score were recorded at specific timings. MAP above 20% from baseline was considered significant and treated with nitroglycerine. Results : In group I, there was a significant increase in hemodynamic variables during intubation pneumoperitoneum and extubation (P<0.001. Clonidine given 1 μg/kg intravenous attenuated hemodynamic stress response to pneumoperitoneum (P<0.05, but not that associated with intubation and extubation. Clonidine 2 μg/kg intravenous prevented hemodynamic stress response to pneumoperitoneum and that associated with intubation and extubation (P<0.05. As against 14 and 2 patients in groups I and II respectively, no patient required nitroglycerine infusion in group III. Conclusions : Clonidine, 2 μg/ kg intravenously, 30 min before induction is safe and effective in preventing the hemodynamic stress response during laparoscopic cholecystectomy.

  17. Novel MRI approaches for assessing cerebral hemodynamics in ischemic cerebrovascular disease.

    Science.gov (United States)

    Donahue, Manus J; Strother, Megan K; Hendrikse, Jeroen

    2012-03-01

    Changes in cerebral hemodynamics underlie a broad spectrum of ischemic cerebrovascular disorders. An ability to accurately and quantitatively measure hemodynamic (cerebral blood flow and cerebral blood volume) and related metabolic (cerebral metabolic rate of oxygen) parameters is important for understanding healthy brain function and comparative dysfunction in ischemia. Although positron emission tomography, single-photon emission tomography, and gadolinium-MRI approaches are common, more recently MRI approaches that do not require exogenous contrast have been introduced with variable sensitivity for hemodynamic parameters. The ability to obtain hemodynamic measurements with these new approaches is particularly appealing in clinical and research scenarios in which follow-up and longitudinal studies are necessary. The purpose of this review is to outline current state-of-the-art MRI methods for measuring cerebral blood flow, cerebral blood volume, and cerebral metabolic rate of oxygen and provide practical tips to avoid imaging pitfalls. MRI studies of cerebrovascular disease performed without exogenous contrast are synopsized in the context of clinical relevance and methodological strengths and limitations.

  18. Acute effects of ferumoxytol on regulation of renal hemodynamics and oxygenation

    Science.gov (United States)

    Cantow, Kathleen; Pohlmann, Andreas; Flemming, Bert; Ferrara, Fabienne; Waiczies, Sonia; Grosenick, Dirk; Niendorf, Thoralf; Seeliger, Erdmann

    2016-01-01

    The superparamagnetic iron oxide nanoparticle ferumoxytol is increasingly used as intravascular contrast agent in magnetic resonance imaging (MRI). This study details the impact of ferumoxytol on regulation of renal hemodynamics and oxygenation. In 10 anesthetized rats, a single intravenous injection of isotonic saline (used as volume control) was followed by three consecutive injections of ferumoxytol to achieve cumulative doses of 6, 10, and 41 mg Fe/kg body mass. Arterial blood pressure, renal blood flow, renal cortical and medullary perfusion and oxygen tension were continuously measured. Regulation of renal hemodynamics and oxygenation was characterized by dedicated interventions: brief periods of suprarenal aortic occlusion, hypoxia, and hyperoxia. None of the three doses of ferumoxytol resulted in significant changes in any of the measured parameters as compared to saline. Ferumoxytol did not significantly alter regulation of renal hemodynamics and oxygenation as studied by aortic occlusion and hypoxia. The only significant effect of ferumoxytol at the highest dose was a blunting of the hyperoxia-induced increase in arterial pressure. Taken together, ferumoxytol has only marginal effects on the regulation of renal hemodynamics and oxygenation. This makes ferumoxytol a prime candidate as contrast agent for renal MRI including the assessment of renal blood volume fraction. PMID:27436132

  19. Cerebral hemodynamics: concepts of clinical importance

    Directory of Open Access Journals (Sweden)

    Edson Bor-Seng-Shu

    2012-05-01

    Full Text Available Cerebral hemodynamics and metabolism are frequently impaired in a wide range of neurological diseases, including traumatic brain injury and stroke, with several pathophysiological mechanisms of injury. The resultant uncoupling of cerebral blood flow and metabolism can trigger secondary brain lesions, particularly in early phases, consequently worsening the patient's outcome. Cerebral blood flow regulation is influenced by blood gas content, blood viscosity, body temperature, cardiac output, altitude, cerebrovascular autoregulation, and neurovascular coupling, mediated by chemical agents such as nitric oxide (NO, carbon monoxide (CO, eicosanoid products, oxygen-derived free radicals, endothelins, K+, H+, and adenosine. A better understanding of these factors is valuable for the management of neurocritical care patients. The assessment of both cerebral hemodynamics and metabolism in the acute phase of neurocritical care conditions may contribute to a more effective planning of therapeutic strategies for reducing secondary brain lesions. In this review, the authors have discussed concepts of cerebral hemodynamics, considering aspects of clinical importance.

  20. [Hemodynamic evaluation of the patient with microvarices].

    Science.gov (United States)

    Alvarez Sánchez, J A; Vega Gómez, M E; Rodríguez Lacaba, B; Martínez Griñán, M A

    1992-01-01

    The present study included 21 lower limbs with micro varicosities, 56 lower limbs with retrograde flow-varicosities (positive Rivlin) and 35 health lower limbs. Technics used for diagnosis were: Doppler ultrasonography and strain gauge plethysmography. We found a higher incidence of valvular failure on the varicose patients with retrograde flow (showing changes on their viscoelastic features of their venous walls). On the contrary, patient with microvaricosities showed an hemodynamics similar to the healty patient: we did not found any difference on the variables analyzed between the two groups. We conclude that the presence of microvaricosities has no influence on the analyzed hemodynamic parametres.

  1. Non-hemodynamic predictors of blood pressure in recreational sport ...

    African Journals Online (AJOL)

    Non-hemodynamic predictors of blood pressure in recreational sport practitioners in ... that regular physical activity is an efficient means to control high blood pressure. ... structures can be effective in managing hemodynamic health problems.

  2. Hemodynamics of physiological blood flow in the aorta with nonlinear anisotropic heart valve

    Science.gov (United States)

    Sotiropoulos, Fotis; Gilmanov, Anvar; Stolarski, Henryk

    2016-11-01

    The hemodynamic blood flow in cardiovascular system is one of the most important factor, which causing several vascular diseases. We developed a new Curvilinear Immersed Boundary - Finite Element - Fluid Structure Interaction (CURVIB-FE-FSI) method to analyze hemodynamic of pulsatile blood flow in a real aorta with nonlinear anisotropic aortic valve at physiological conditions. Hyperelastic material model, which is more realistic for describing heart valve have been incorporated in the CURVIB-FE-FSI code to simulate interaction of aortic heart valve with pulsatile blood flow. Comparative studies of hemodynamics for linear and nonlinear models of heart valve show drastic differences in blood flow patterns and hence differences of stresses causing impact at leaflets and aortic wall. This work is supported by the Lillehei Heart Institute at the University of Minnesota.

  3. Differences in estimates of size distribution of beryllium powder materials using phase contrast microscopy, scanning electron microscopy, and liquid suspension counter techniques.

    Science.gov (United States)

    Stefaniak, Aleksandr B; Hoover, Mark D; Dickerson, Robert M; Day, Gregory A; Breysse, Patrick N; Scripsick, Ronald C

    2007-02-28

    Accurate characterization of the physicochemical properties of aerosols generated for inhalation toxicology studies is essential for obtaining meaningful results. Great emphasis must also be placed on characterizing particle properties of materials as administered in inhalation studies. Thus, research is needed to identify a suite of techniques capable of characterizing the multiple particle properties (i.e., size, mass, surface area, number) of a material that may influence toxicity. The purpose of this study was to characterize the morphology and investigate the size distribution of a model toxicant, beryllium. Beryllium metal, oxides, and alloy particles were aerodynamically size-separated using an aerosol cyclone, imaged dry using scanning electron microscopy (SEM), then characterized using phase contrast microscopy (PCM), a liquid suspension particle counter (LPC), and computer-controlled SEM (CCSEM). Beryllium metal powder was compact with smaller sub-micrometer size particles attached to the surface of larger particles, whereas the beryllium oxides and alloy particles were clusters of primary particles. As expected, the geometric mean (GM) diameter of metal powder determined using PCM decreased with aerodynamic size, but when suspended in liquid for LPC or CCSEM analysis, the GM diameter decreased by a factor of two (p particles attached to the surface of larger particles and/or particle agglomerates detach in liquid, thereby shifting the particle size distribution downward. The GM diameters of the oxide materials were similar regardless of sizing technique, but observed differences were generally significant (p aerodynamic cluster size will dictate deposition in the lung, but primary particle size may influence biological activity. The GM diameter of alloy particles determined using PCM became smaller with decreasing aerodynamic size fraction; however, when suspended in liquid for CCSEM and LPC analyses, GM particle size decreased by a factor of two (p

  4. Post-Treatment Hemodynamics of a Basilar Aneurysm and Bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J; Hartman, J; Rodriguez, J; Maitland, D

    2008-01-16

    Aneurysm re-growth and rupture can sometimes unexpectedly occur following treatment procedures that were initially considered to be successful at the time of treatment and post-operative angiography. In some cases, this can be attributed to surgical clip slippage or endovascular coil compaction. However, there are other cases in which the treatment devices function properly. In these instances, the subsequent complications are due to other factors, perhaps one of which is the post-treatment hemodynamic stress. To investigate whether or not a treatment procedure can subject the parent artery to harmful hemodynamic stresses, computational fluid dynamics simulations are performed on a patient-specific basilar aneurysm and bifurcation before and after a virtual endovascular treatment. The simulations demonstrate that the treatment procedure produces a substantial increase in the wall shear stress. Analysis of the post-treatment flow field indicates that the increase in wall shear stress is due to the impingement of the basilar artery flow upon the aneurysm filling material and to the close proximity of a vortex tube to the artery wall. Calculation of the time-averaged wall shear stress shows that there is a region of the artery exposed to a level of wall shear stress that can cause severe damage to endothelial cells. The results of this study demonstrate that it is possible for a treatment procedure, which successfully excludes the aneurysm from the vascular system and leaves no aneurysm neck remnant, to elevate the hemodynamic stresses to levels that are injurious to the immediately adjacent vessel wall.

  5. Pediatric Brain: Repeated Exposure to Linear Gadolinium-based Contrast Material Is Associated with Increased Signal Intensity at Unenhanced T1-weighted MR Imaging.

    Science.gov (United States)

    Flood, Thomas F; Stence, Nicholas V; Maloney, John A; Mirsky, David M

    2017-01-01

    Purpose To determine whether repeated exposure of the pediatric brain to a linear gadolinium-based contrast agent (GBCA) is associated with an increase in signal intensity (SI) relative to that in GBCA-naive control subjects at unenhanced T1-weighted magnetic resonance (MR) imaging. Materials and Methods This single-center, retrospective study was approved by the institutional review board and compliant with HIPAA. The authors evaluated 46 pediatric patients who had undergone at least three GBCA-enhanced MR examinations (30 patients for two-group analysis and 16 for pre- and post-GBCA exposure comparisons) and 57 age-matched GBCA-naive control subjects. The SI in the globus pallidus, thalamus, dentate nucleus, and pons was measured at unenhanced T1-weighted MR imaging. Globus pallidus-thalamus and dentate nucleus-pons SI ratios were calculated and compared between groups and relative to total cumulative gadolinium dose, age, sex, and number of and mean time between GBCA-enhanced examinations. Analysis included the Wilcoxon signed rank test, Wilcoxon rank sum test, and Spearman correlation coefficient. Results Patients who underwent multiple GBCA-enhanced examinations had increased SI ratios within the dentate nucleus (mean SI ratio ± standard error of the mean for two-group comparison: 1.007 ± 0.0058 for GBCA-naive group and 1.046 ± 0.0060 for GBCA-exposed group [P mean SI ratio for pre- and post-GBCA comparison: 0.995 ± 0.0062 for pre-GBCA group and 1.035 ± 0.0063 for post-GBCA group [P mean SI ratio for two-group comparison: 1.131 ± 0.0070 for GBCA-naive group and 1.014 ± 0.0091 for GBCA-exposed group [P = .21]; mean SI ratio for pre- and post-GBCA comparison: 1.068 ± 0.0094 for pre-GBCA group and 1.093 ± 0.0134 for post-GBCA group [P = .12]). There was a significant correlation between dentate nucleus SI and total cumulative gadolinium dose (r = 0.4; 95% confidence interval [CI]: 0.03, 0.67; P = .03), but not between dentate nucleus SI and patient age

  6. Segmental Difference of the Hepatic Fibrosis from Chronic Viral Hepatitis due to Hepatitis B versus C Virus Infection: Comparison Using Dual Contrast Material-Enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae Ho; Yu, Jeong Sik; Chung, Jae Joon; Kim, Joo Hee; Kim, Ki Whang [Gangnam Severance Hospital, Yensei University College of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophy-hypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran. Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2-weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients. There were significant intersegmental differences in fibrosis grades of the C-viral group (p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship (p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS. The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch.

  7. Micro-radiography and micro-computerized tomography with absorption and phase contrast for materials characterization; Mikro-Radiografie und Mikro-Computertomografie mit Absorptions- und Phasenkontrast fuer die Materialcharakterisierung

    Energy Technology Data Exchange (ETDEWEB)

    Kastner, Johann [FH Oberoesterreich, Wels (Austria)

    2017-08-01

    The contribution describes modern techniques in micro-radiography and micro-computerized tomography for materials characterization using absorption and phase contrast. Using micro- and nano-focus tubes and adequate high.-resolution detectors it is possible to reach resolutions significantly below 1 micron. The CT technology allows in-situ deformation testing to study the damaging mechanism of materials. The application of the Talbot-Lau interferometer with CT a differential phase contrast tomography is available. Dark-field tomography is used to study individual carbon fiber bundles in carbon fiber reinforced laminates.

  8. Invasive hemodynamic characterization of heart failure with preserved ejection fraction

    DEFF Research Database (Denmark)

    Andersen, Mads Jønsson; Borlaug, Barry A

    2014-01-01

    Recent hemodynamic studies have advanced our understanding of heart failure with preserved ejection fraction (HFpEF). Despite improved pathophysiologic insight, clinical trials have failed to identify an effective treatment for HFpEF. Invasive hemodynamic assessment can diagnose or exclude HFpEF......, making it invaluable in understanding the basis of the disease. This article reviews the hemodynamic mechanisms underlying HFpEF and how they manifest clinically, discusses invasive hemodynamic assessment as a diagnostic tool, and explores how invasive hemodynamic profiling may allow understanding...

  9. Model for Electron-Beam-Induced Current Analysis of mc-Si Addressing Defect Contrast Behavior in Heavily Contaminated PV Material: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, H.; Gorman, B.; Al-Jassim, M.

    2012-06-01

    Much work has been done to correlate electron-beam-induced current (EBIC) contrast behavior of extended defects with the character and degree of impurity decoration. However, existing models fail to account for recently observed contrast behavior of defects in heavily contaminated mc-Si PV cells. We have observed large increases in defect contrast with decreasing temperature for all electrically active defects, regardless of their initial contrast signatures at ambient temperature. This negates the usefulness of the existing models in identifying defect character and levels of impurity decoration based on the temperature dependence of the contrast behavior. By considering the interactions of transition metal impurities with the silicon lattice and extended defects, we attempt to provide an explanation for these observations. Our findings will enhance the ability of the PV community to understand and mitigate the effects of these types of defects as the adoption of increasingly lower purity feedstocks for mc-Si PV production continues.

  10. Venous hemodynamic changes in lower limb venous disease

    DEFF Research Database (Denmark)

    Lee, Byung Boong; Nicolaides, Andrew N; Myers, Kenneth

    2016-01-01

    ). Their aim was to confirm or dispel long-held hemodynamic principles and to provide a comprehensive review of venous hemodynamic concepts underlying the pathophysiology of lower limb venous disorders, their usefulness for investigating patients and the relevant hemodynamic changes associated with various......There are excellent guidelines for clinicians to manage venous diseases but few reviews to assess their hemodynamic background. Hemodynamic concepts that evolved in the past have largely remained unchallenged in recent decades, perhaps due to their often complicated nature and in part due...... not provide the physiological basis for understanding the hemodynamics of flow, pressure, compliance and resistance. Hemodynamic investigations appear to provide a better correlation with post-treatment clinical outcome and quality of life than ultrasound findings. There is a far better prospect...

  11. Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants.

    Directory of Open Access Journals (Sweden)

    Caroline C O'Brien

    Full Text Available Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design.Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D 'clouds' of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively to individual strut-wall configurations (average displacement error ~15 μm. This framework facilitated hemodynamic simulation (n = 1 vessel, showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors.Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments.

  12. Emergency management of hemodynamically unstable pelvic fractures

    Directory of Open Access Journals (Sweden)

    ZHAO Xiao-gang

    2012-02-01

    Full Text Available 【Abstract】Pelvic fractures are serious injuries. Death within 24 hours is most often a result of acute blood loss. The emergency management of these patients is challenging and controversial. The key issues in its management are identifying the site(s of hemorrhage and then controlling the bleeding. Management of hemodynamically unstable patients with pelvic fracture requires a multidisci- plinary team. The issues addressed in this management algorithm are diagnostic evaluation, damage control resuscitation, indications for noninvasive pelvic stabilization, preperitoneal pelvic packing and the critical decisions concerning surgical options and angiography. This review article focuses on the recent body of know- ledge on those determinations. Key words: Pelvis; Hemodynamic; Emergencies; Practice management

  13. [Invasive and minimally invasive hemodynamic monitoring].

    Science.gov (United States)

    Hansen, Matthias

    2016-10-01

    Advanced hemodynamic monitoring is necessary for adequate management of high-risk patients or patients with derangement of circulation. Studies demonstrate a benefit of early goal directed therapy in unstable cardiopulmonary situations. In these days we have different possibilities of minimally invasive or invasive hemodynamic monitoring. Minimally invasive measurements like pulse conture analysis or pulse wave analysis being less accurate under some circumstances, however only an artery catheter is needed for cardiac output monitoring. Pulmonary artery, transpulmonary thermodilution and lithium dilution technology have acceptable accuracy in cardiac output measurement. For therapy of unstable circulation there are additionally parameters to obtain. The pulmonary artery catheter is the device with the largest rate of complications, used by a trained crew and with a correct indication, his use is unchained justified.

  14. Biology and hemodynamics of aneurismal vasculopathies

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Vitor Mendes, E-mail: vitormpbr@hotmail.com [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland); Brina, Olivier, E-mail: olivier.brina@hcuge.ch [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland); Gonzalez, Ana Marcos, E-mail: ana.marcosgonzalez@hcuge.ch [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland); Narata, Ana Paula, E-mail: ana.p.narata@hcuge.ch [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland); Ouared, Rafik, E-mail: rafik.ouared@unige.ch [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland); Karl-Olof, Lovblad, E-mail: Karl-olof.lovblad@hcuge.ch [Interventional Neuroradiology Unit, Service of Neuroradiology, University Hospital of Geneva (Switzerland)

    2013-10-01

    Aneurysm vasculopathies represents a group of vascular disorders that share a common morphological diagnosis: a vascular dilation, the aneurysm. They can have a same etiology and a different clinical presentation or morphology, or have different etiology and very similar anatomical geometry. The biology of the aneurysm formation is a complex process that will be a result of an endogenous predisposition and epigenetic factors later on including the intracranial hemodynamics. We describe the biology of saccular aneurysms, its growth and rupture, as well as, current concepts of hemodynamics derived from application of computational flow dynamics on patient specific vascular models. Furthermore, we describe different aneurysm phenotypes and its extremely variability on morphological and etiological presentation.

  15. Cerebral hemodynamics in normal-pressure hydrocephalus. Evaluation by 133Xe inhalation method and dynamic CT study

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, N.; Kusunoki, T.; Wakabayashi, T.; Matsumoto, S.

    1984-09-01

    Cerebral hemodynamics in 31 patients with suspected normal-pressure hydrocephalus were studied by means of the xenon-133 (133Xe) inhalation method and on dynamic computerized tomography (CT) scanning. Cerebral blood flow (CBF) is reduced in all patients with dementia. Hypoperfusion was noted in a frontal distribution in these patients compared with normal individuals. There was no difference in CBF patterns between patients with good and those with poor outcome. The CBF was increased following cerebrospinal fluid (CSF) shunting in patients who responded to that procedure: increase in flow correlated with clinical improvement, frontal and temporal lobe CBF was most markedly increased, and the CBF pattern became normal. In contrast, CBF was decreased after shunt placement in patients who were considered to have suffered from degenerative dementia, as evidenced by non-response to shunting. Dynamic computerized tomography studies demonstrated that patients with a good outcome showed a postoperative reduction in mean transit time of contrast material, most prominent in the frontal and temporal gray matter, and slight in the deep frontal structures, but not in the major cerebral vessels. Patients with poor outcome after shunting, however, had an increase in transit time in all regions. This corresponded well with the results as determined by the 133Xe inhalation method.

  16. Time-varying modeling of cerebral hemodynamics.

    Science.gov (United States)

    Marmarelis, Vasilis Z; Shin, Dae C; Orme, Melissa; Rong Zhang

    2014-03-01

    The scientific and clinical importance of cerebral hemodynamics has generated considerable interest in their quantitative understanding via computational modeling. In particular, two aspects of cerebral hemodynamics, cerebral flow autoregulation (CFA) and CO2 vasomotor reactivity (CVR), have attracted much attention because they are implicated in many important clinical conditions and pathologies (orthostatic intolerance, syncope, hypertension, stroke, vascular dementia, mild cognitive impairment, Alzheimer's disease, and other neurodegenerative diseases with cerebrovascular components). Both CFA and CVR are dynamic physiological processes by which cerebral blood flow is regulated in response to fluctuations in cerebral perfusion pressure and blood CO2 tension. Several modeling studies to date have analyzed beat-to-beat hemodynamic data in order to advance our quantitative understanding of CFA-CVR dynamics. A confounding factor in these studies is the fact that the dynamics of the CFA-CVR processes appear to vary with time (i.e., changes in cerebrovascular characteristics) due to neural, endocrine, and metabolic effects. This paper seeks to address this issue by tracking the changes in linear time-invariant models obtained from short successive segments of data from ten healthy human subjects. The results suggest that systemic variations exist but have stationary statistics and, therefore, the use of time-invariant modeling yields "time-averaged models" of physiological and clinical utility.

  17. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Martijn A.M. den; Pelgrim, Gert Jan; Pundziute, Gabija; Heuvel, Edwin R. van den; Oudkerk, Matthijs; Vliegenthart, Rozemarijn, E-mail: r.vliegenthart@umcg.nl

    2015-01-15

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis.

  18. Hemodynamic and electrocardiographic effects of ioversol during cardiac angiography. Comparison with iopamidol and diatrizoate.

    Science.gov (United States)

    Hirshfeld, J W; Wieland, J; Davis, C A; Giles, B D; Passione, D; Ray, M B; Ripley, N S

    1989-02-01

    We studied the hemodynamic and electrocardiographic responses to left ventriculography and coronary arteriography with three angiographic contrast agents. Two were nonionic agents (ioversol 32% iodine, 60 patients, and iopamidol 37% iodine, 30 patients). The third was a conventional ionic agent (diatrizoate 37% iodine, 30 patients). Cardiovascular hemodynamics and the electrocardiogram were recorded for 5 minutes after left ventricular injection and for 2 minutes after coronary injections. Following left ventriculography, diatrizoate caused a greater increase in cardiac output, left ventricular end diastolic pressure, and corrected QT interval while causing a greater decrease in arterial pressure than did either ioversol or iopamidol, which were indistinguishable from each other. Following left coronary arteriography, diatrizoate caused a significant decrease in heart rate, prolongation of the corrected QT interval, and increase in T wave amplitude. In contrast, neither ioversol nor iopamidol caused significant changes in any electrocardiographic parameters. Adverse reactions were more common with diatrizoate than with either ioversol or iopamidol. There were no recognizable differences in angiographic image quality among the three agents. We conclude that the angiographic performance of ioversol is equivalent to that of iopamidol and that both cause less hemodynamic and electrocardiographic disturbance than diatrizoate.

  19. Comparison of hemodynamic effects of lidocaine, prilocaine and mepivacaine solutions without vasoconstrictor in hypertensive patients

    Directory of Open Access Journals (Sweden)

    Bahadir Ezmek

    2010-08-01

    Full Text Available OBJECTIVE: Local anesthetic solutions with vasoconstrictors are not contraindicated in hypertensive patients, but due to their hemodynamic effects, local anesthetics without vasoconstrictors are mainly preferred by the clinicians. The aim of this study was to compare hemodynamic effects of three different local anesthetics without vasoconstrictors during tooth extraction in hypertensive patients. MATERIAL AND METHODS: Sixty-five mandibular molars and premolars were extracted in 60 hypertensive patients (29 females and 31 males; mean age: 66.95 ± 10.87 years; range: 38 to 86 years old. Inferior alveolar and buccal nerve blocks were performed with 2% lidocaine hydrochloride (HCl, 2% prilocaine HCl or 3% mepivacaine HCl without vasoconstrictor. Hemodynamic parameters namely systolic blood pressure (SBP, diastolic blood pressure (DBP, mean arterial pressure (MAP, heart rate (HR, saturation rate (SR, rate pressure product (RPP and pressure rate quotient (PRQ were investigated before and at different intervals after anesthetic injection. RESULTS: The hemodynamic effects of the three agents were similar to each other, although some significance was observed for DBP, MAP, RPP and PRQ values in the lidocaine, prilocaine and mepivacaine groups. CONCLUSION: Lidocaine, prilocaine and mepivacaine solutions without vasoconstrictor can be safely used in hypertensive patients. It is advisable that dental practitioners select anesthetic solutions for hypertensive patients considering their cardiovascular effects in order to provide patient comfort and safety.

  20. Occupational exposure in hemodynamic; Exposicao ocupacional em hemodinamica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Amanda J.; Fernandes, Ivani M.; Silva, Paula P. Nou; Sordi, Gian Maria A.A.; Carneiro, Janete C.G.G., E-mail: ajsilva@ipen.b, E-mail: imfernandes@ipen.b, E-mail: ppsilva@ipen.b, E-mail: gmsordi@ipen.b, E-mail: janetegc@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-10-26

    This paper has an objective to perform a radiometric survey at a hemodynamic service. Besides, it was intended to evaluate the effective dose of health professionals and to provide data which can contribute with minimization of exposures during the realization of hemodynamic procedure. The radiometric survey was realized in the real environment of work simulating the conditions of a hemodynamic study with a ionization chamber

  1. Hemodynamic Change in Pulmonary Vein Stenosis after Radiofrequency Ablation: Assessment with Magnetic Resonance Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Doyoung; Jung, Jung Im; Oh, Yong Seog; Youn, Ho Joong [Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2012-11-15

    We present a case of pulmonary vein (PV) stenosis after radio-frequency (RF) ablation, in which a hemodynamic change in the pulmonary artery was similar to that of congenital PV atresia on time-resolved contrast-enhanced magnetic resonance angiography (TR-MRA). A 48-year-old man underwent RF ablation due to atrial fibrillation. The patient subsequently complained of hemoptysis, dyspnea on exertion, and right chest pain. Right PV stenosis after catheter ablation was diagnosed through chest computed tomography and lung perfusion scan. Pulmonary TR-MRA revealed the pulmonary artery via systemic arterial collaterals and draining systemic collateral veins. On a velocity-encoded cine image, the flow direction of the right pulmonary artery was reversed in the diastolic phase and the left pulmonary artery demonstrated continuous forward flow throughout the cardiac cycle. These hemodynamic changes were similar to those seen in congenital unilateral PV atresia.

  2. Contrast-Enhanced Harmonic Ultrasonography for the Assessment of Prostate Cancer Aggressiveness: a Preliminary Study

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yunkai; Chen, Yaqing; Jiang, Jun [Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai (China); Wang, Ren; Zhou, Yongchang; Zhang, Huizhen [Sixth People' s Hospital Affiliated to Shanghai Jiaotong University, Shanghai (China)

    2010-02-15

    To determine whether contrast-enhanced harmonic ultrasonography can be used to predict the aggressiveness of prostate cancer. Contrast-enhanced harmonic ultrasonography was performed in 103 patients suspected of prostate cancer before biopsy. Time intensity curves were reconstructed for systematic biopsy sites and sonographic abnormalities. The characteristics of the curves were described using hemodynamic indices including arrival time (AT), time-to-peak (TTP), and peak intensity (PI). The differences of hemodynamic indices between high-grade and low-grade cancer were analyzed and the correlations between the hemodynamic indices and biopsy Gleason score were studied. Prostate cancer was detected in 41 of 103 patients and there were significant differences in the hemodynamic indices between the biopsy sites of the non-malignant patients and prostate cancer lesions (p < 0.05). The prostate biopsies revealed 154 prostate cancer lesions, including 31 low-grade lesions and 123 high-grade lesions. The hemodynamic indices AT and TTP of highgrade tumors were significantly shorter than those of low-grade tumors (p = 0.001, 0.002). In addition, high-grade peripheral zone (PZ) tumors had higher PI than low-grade PZ tumors (p = 0.009). The PZ prostate cancer Gleason score correlated with PI, AT and TTP, with Spearman correlation coefficients of 0.223, -0.335, and -0.351, respectively (p = 0.013, < 0.001 and < 0.001). Contrast-enhanced ultrasound measurements of hemodynamic indices correlate with the prostate cancer Gleason score.

  3. Hemodynamic significance of internal carotid artery disease

    DEFF Research Database (Denmark)

    Schroeder, T

    1988-01-01

    . Examination of periorbital flow direction or oculoplethysmography could be used as a screening procedure. Negative tests most certainly rule out any severe pressure gradient across the stenosis, irrespective of the luminal reduction. A positive result, on the other hand, should be further quantified since...... cerebral hemodynamics in terms of increased flow through the reconstructed vessel and elimination of pressure gradients. The cerebral blood flow, though remains unchanged in the majority of patients, at least when measured at baseline. Only in those patients with a reduction in perfusion pressure can...

  4. Hemodynamic response to the upright posture.

    Science.gov (United States)

    Smith, J J; Porth, C M; Erickson, M

    1994-05-01

    The authors' objective was to review previous studies of immediate (first 30 seconds) and stabilized (30 seconds to 20 minutes) hemodynamic responses of healthy adults to the head-up posture, with particular reference to alteration of such responses in the elderly and the usefulness of such data in the diagnosis of orthostatic hypotension. The immediate response in healthy young adults is characterized by a prompt rise in heart rate, which peaks at about 8 to 15 seconds and then tapers; the arterial pressure and total vascular resistance decrease sharply at 5 to 10 seconds, followed by a rapid rebound and overshoot. Over the first 30 seconds there is a steady parallel decline of thoracic blood volume and stroke volume; there is also an initial surge of cardiac output followed by a steady decrease. During the stabilized response (30 seconds to 20 minutes), the hemodynamic variables are relatively steady, showing average increases in heart rate of about 15 to 30%, in diastolic pressure of 10 to 15%, and in total vascular resistance of 30 to 40%; during the 5th to 20th minutes there are also decreases in thoracic blood volume averaging about 25 to 30%, in cardiac output 15 to 30%, and in pulse pressure about 5 to 10%. It is evident that in normal human subjects, assumption of the upright posture results in profound hemodynamic changes, most of them occurring during the first 30 seconds. In elderly subjects (aged 60-69 years), there are, in the upright posture, lesser increments of heart rate and diastolic pressure, but no significant differences from younger age groups in the response of thoracic blood volume, cardiac output or total vascular resistance. However, beginning at about age 75, there is an increasing incidence of orthostatic hypotension, which averages about 14 to 20% at age 75 and older. The tendency toward orthostatic hypotension in the elderly is due (1) to the structural and functional changes in the circulation itself, (2) to a decline in autonomic

  5. Emergency management of hemodynamically unstable pelvic fractures

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiao-gang

    2011-01-01

    Pelvic fractures are serious injuries.Death within 24 hours is most often a result of acute blood loss.The emergency management of these patients is challenging and controversial.The key issues in its management are identifying the site(s) of hemorrhage and then controlling the bleeding.Management of hemodynamically unstable patients with pelvic fracture requires a multidisciplinary team.The issues addressed in this management algorithm are diagnostic evaluation,damage control resuscitation,indications for noninvasive pelvic stabilization,preperitoneal pelvic packing and the critical decisions concerning surgical options and angiography.This review article focuses on the recent body of knowledge on those determinations.

  6. [Multicenter trial for optimization of bolus tracking settings and contrast material injection protocol in arterial dominant phase of dynamic computed tomography for diagnosis of hepatocellular carcinoma].

    Science.gov (United States)

    Yoshikawa, Shushi; Okada, Masahiro; Kondo, Hiroshi; Sou, Hironobu; Murakami, Takamichi; Kanematsu, Masayuki; Ichikawa, Tomoaki; Hayakawa, Akiko; Shiosakai, Kazuhito; Awai, Kazuo; Yoshimitsu, Kengo; Yamashita, Yasuyuki

    2014-08-01

    Alongside current improvements in the performance of computer tomography (CT) systems, there has been an increase in the use of bolus tracking (BT) to acquire arterial dominant phase images for dynamic CT at optimal timing for characterization of liver focal lesions. However, optimal BT settings have not been established. In the present study, methods of contrast enhancement and BT setting values were evaluated using a multicenter post-marketing surveillance study on contrast media used in patients with chronic hepatitis and/or cirrhosis who had undergone liver dynamic CT for diagnosis of hepatocellular carcinoma, conducted by Daiichi Sankyo Co., Ltd. The results suggested the contrast injection method to be clinically useful if the amount of iodine per kilogram of body weight is set at 600 mg/kg and the injection duration at 30 s. To achieve a good arterial dominant scan under conditions where the injection duration is fixed at 30 s or the average injection duration is 34 s using the fixed injection rate method, the scan delay time should ideally to be set to longer than 13 s. If using the BT method, we recommend that the BT settings should be revalidated in reference to our results.

  7. Hemodynamic, ventilator, and ECG changes in pediatric patients undergoing extraction

    Directory of Open Access Journals (Sweden)

    Y K Sanadhya

    2013-01-01

    Full Text Available Background: Dental treatment induces pain anxiety and fear. This study was conducted to assess the changes in hemodynamic, ventilator, and electrocardiograph changes during extraction procedure among 12-15-year-old children and compare these changes with anxiety, fear, and pain. Materials and Methods: A purposive sample of 60 patients selected based on inclusion and exclusion criteria underwent study procedure in the dental OPD of a medical college and hospital. The anxiety, fear, and pain were recorded by dental anxiety scale, dental fear scale, and visual analogue scale, respectively, before the start of the procedure. The systolic blood pressure, diastolic blood pressure, heart rate, oxygen saturation, and electrocardiogram changes were monitored during the extraction procedure. The recording was taken four times (preinjection phase, injection, extraction, and postextraction and was analyzed. Results: At the preinjection phase the mean vales were systolic blood pressure (128 ± 11.2, diastolic blood pressure (85.7 ± 6.3, heart rate (79.7 ± 9.3, and oxygen saturation (97.9 ± 5.8. These values increased in injection phases and decreased in extraction phase and the least values were found after 10 min of procedure and this relation was significant for all parameters except oxygen saturation (P = 0.48, NS. ECG abnormalities were seen among 22 patients and were significant before and after injection of Local anesthetic (P = 0.0001, S. Conclusions: Anxiety, fear, and pain have an effect on hemodynamic, ventilator, and cardiovascular parameters during the extraction procedure and hence behavioral management has to be emphasized among children in dental clinics.

  8. Comparative study of intravenously administered clonidine and magnesium sulfate on hemodynamic responses during laparoscopic cholecystectomy

    Directory of Open Access Journals (Sweden)

    Nand Kishore Kalra

    2011-01-01

    Full Text Available Background: Both magnesium and clonidine are known to inhibit catecholamine and vasopressin release and attenuate hemodynamic response to pneumoperitoneum. This randomized, double blinded, placebo controlled study has been designed to assess which agent attenuates hemodynamic stress response to pneumoperitoneum better. Materials and Methods: 120 patients undergoing elective laparoscopic cholecystectomy were randomized into 4 groups of 30 each. Group K patients received 50 ml normal saline over a period of 15 min after induction and before pneumoperitoneum, group M patients received 50 mg/kg of magnesium sulfate in normal saline (total volume 50 ml over same time duration. Similarly group C1 patients received 1 μg/kg clonidine and group C2 1.5 μg/kg clonidine respectively in normal saline (total volume 50 ml. Blood pressure and heart rate were recorded before induction (baseline value, at the end of infusions and every 5 min after pneumoperitoneum. Statistical Analysis: Paired t test was used for intra-group comparison and ANOVA for inter-group comparison. Results: Systolic blood pressure was significantly higher in control group as compared to all other groups during pneumoperitoneum. On comparing patients in group M and group C1, no significant difference in systolic BP was found at any time interval. Patients in group C2 showed best control of systolic BP. As compared to group M and group C1, BP was significantly lower at 10, 30 and 40 min post pneumoperitoneum. No significant episodes of hypotension were found in any of the groups. Extubation time and time to response to verbal command like eye opening was significantly longer in group M as compared to other groups. Conclusion: Administration of magnesium sulfate or clonidine attenuates hemodynamic response to pneumoperitoneum. Although magnesium sulfate 50 mg/kg produces hemodynamic stability comparable to clonidine 1 μg/kg, clonidine in doses of 1.5μg/kg blunts the hemodynamic response

  9. Hemodynamic Consequences of Malignant Ascites in Epithelial Ovarian Cancer Surgery*: A Prospective Substudy of a Randomized Controlled Trial.

    Science.gov (United States)

    Hunsicker, Oliver; Fotopoulou, Christina; Pietzner, Klaus; Koch, Mandy; Krannich, Alexander; Sehouli, Jalid; Spies, Claudia; Feldheiser, Aarne

    2015-12-01

    Malignant ascites (MA) is most commonly observed in patients scheduled for epithelial ovarian cancer (EOC) surgery and is supposed as a major risk factor promoting perioperative hemodynamic deterioration. We aimed to assess the hemodynamic consequences of MA on systemic circulation in patients undergoing cytoreductive EOC surgery.This study is a predefined post-hoc analysis of a randomized controlled pilot trial comparing intravenous solutions within a goal-directed algorithm to optimize hemodynamic therapy in patients undergoing cytoreductive EOC surgery. Ascites was used to stratify the EOC patients prior to randomization in the main study. We analyzed 2 groups according to the amount of ascites (NLAS: none or low ascites [500 mL]). Differences in hemodynamic variables with respect to time were analyzed using nonparametric analysis for longitudinal data and multivariate generalized estimating equation adjusting the analysis for the randomized study groups of the main study.A total of 31 patients in the NLAS and 16 patients in the HAS group were analyzed. Although cardiac output was not different between groups suggesting a similar circulatory blood flow, the HAS group revealed higher heart rates and lower stroke volumes during surgery. There were no differences in pressure-based hemodynamic variables. In the HAS group, fluid demands, reflected by the time to reindication of a fluid challenge after preload optimization, increased steadily, whereas stroke volume could not be maintained at baseline resulting in hemodynamic instability after 1.5 h of surgery. In contrast, in the NLAS group fluid demands were stable and stroke volume could be maintained during surgery. Clinically relevant associations of the type of fluid replacement with hemodynamic consequences were particularly observed in the HAS group, in which transfusion of fresh frozen plasma (FFP) was associated to an improved circulatory flow and reduced vasopressor and fluid demands, whereas the

  10. Cerebral hemodynamic dysfunction in parkinsonian patients

    Directory of Open Access Journals (Sweden)

    Mirjana Vladetić

    2009-02-01

    Full Text Available Aim The purpose of this investigation was to determine the cerebral hemodynamics in patients withparkinsonism and the influence of hemodynamic dysfunction in developing the lacunar infarcts.Methods Fifty patients with the signs of parkinsonism were included in this study. The patients weredevided into two subgroups depending on whether they had vascular parkinsonism (VP (N-22 or idiopathicParkinson disease (N-28. The control group consisted of 30 patients who had ischemic stroke.The conventional transcranial dopler sonography was performed to evaluate the cerebral blood flow.To evaluate the cognitive impairment we performed the mini mental state examination to patients withparkinsonism.Results Patients with vascular parkinsonism have greater cognitive disturbances than patients withParkinson disease. In most of the parkinsonian patients the cerebral blood flow was decreased and themicroangiopathy was present.Conclusion In most patients with parkinsonism, the cerebral blood flow was decreased as a consequenceof microangiopathy. In our opinion, this led to lacunar infarction in VP patients, but can also bea risk factor for developing the same changes in patients with idiopathic Parkinson disease.

  11. Cerebrovascular hemodynamics in patients with cerebral arteriosclerosis

    Institute of Scientific and Technical Information of China (English)

    Jianbo Yang; Changcong Cui; Chengbin Wu

    2011-01-01

    The present study observed hemodynamic changes in 26 patients with cerebral arteriosclerosis using a cerebral circulation dynamics detector and transcranial Doppler.In patients with cerebral arteriosclerosis the blood supply and flow rate in the bilateral carotid arteries and the blood flow rate in the anterior cerebral and middle cerebral arteries were similar to normal controls, but the cerebral vascular resistance, critical pressure and pulsatility index were increased, and cerebral arterial elasticity and cerebral blood flow autoregulation were decreased.Compared with the lesioned hemisphere of patients with cerebral infarction, the total blood supply and blood flow rate of patients with cerebral arteriosclerosis were higher.Compared with normal subjects, patients with cerebral arteriosclerosis exhibited cognitive disturbances, mainly in short-term memory, attention, abstract capability, and spatial and executive dysfunction.Results showed that cerebral arteriosclerosis does not directly affect the blood supply of a cerebral hemisphere, but affects cognitive function.The increased cerebral vascular resistance and reduced autoregulation of cerebral blood vessels may be important hemodynamic mechanisms of arteriosclerosis-induced cerebral infarction.

  12. Cerebral hemodynamics and functional prognosis in hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, Osamu; Nishikawa, Michio; Watanabe, Shu; Yamakawa, Hiroyasu; Kinoshita, Yoshimasa; Uno, Akira; Handa, Hajime (Hamamatsu Rosai Hospital, Shizuoka (Japan))

    1989-11-01

    The functional outcome of cerebral hemodynamics in the chronic stage of juvenile hydrocephalus was determined using single photon emission computed tomography (SPECT). Five patients including three with aqueductal stenosis, one with post-meningitic hydrocephalus, and one case with hydrocephalus having developed after repair of a huge occipital encephalocele. Early images of cerebral blood flow (CBF) were obtained 25 minutes after intravenous injection of 123-I-iodoamphetamine (IMP), and late images were scanned 3 hours later. Cerebral blood volume (CBV) was also measured using {sup 99m}Tc in three patients. Twenty cases with adult communicating hydrocephalus were also investigated from the point of view of shunt effectiveness. Although there was no remarkable change in the cerebrovascular bed in the juvenile cases, CBF of the remnant brain parenchyma was good irrespective of the degree of ventricular dilatation. There was a periventricular-related IMP uptake in each case; however, it somehow matched the ventricular span. Functional outcome one to 23 years after the initial shunt operation was good in every case, despite multiple shunt revisions. Redistribution on late images had no bearing on clinical states. In adult cases, 8 patients with effective shunting demonstrated a relatively localized periventricular low perfusion, with preoperative increased cerebrospinal fluid (CSF) pressure. On the contrary, 12 patients with no improvement with or without ventricular-reduced IMP uptake, despite low CSF pressure. The present study indicates that periventricular hemodynamics may play an important role in cerebral function compromised by hydrocephalus. (J.P.N.).

  13. Hemodynamic Consequences of Changes in Microvascular Structure.

    Science.gov (United States)

    Rizzoni, Damiano; Agabiti-Rosei, Claudia; Agabiti-Rosei, Enrico

    2017-10-01

    In hypertension, an increased media-to-lumen ratio of small resistance arteries might play an important role in the increase of vascular resistance, and may also be an adaptive response to the increased hemodynamic load. The presence of morphological alteration in the microvasculature may be associated to an impaired tissue perfusion and/or to the development of target organ damage. Structural alterations in the microcirculation might represent a predictor of the onset of cardio-cerebrovascular events and hypertension complications. A cross-talk between the small and large artery may exaggerate arterial damage, following a vicious circle. Therefore, in the present review, possible hemodynamic consequences of the presence of microvascular structural alterations will be considered, in terms of their time of onset, role in the development and/or maintenance of high blood pressure values, and interrelationships with structural/mechanical alterations of large conductance arteries. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Hemodynamic forces in a model left ventricle

    Science.gov (United States)

    Domenichini, Federico; Pedrizzetti, Gianni

    2016-12-01

    Intraventricular pressure gradients were clinically demonstrated to represent one useful indicator of the left ventricle (LV) function during the development of heart failure. We analyze the fluid dynamics inside a model LV to improve the understanding of the development of hemodynamic forces (i.e., mean pressure gradient) in normal conditions and their modification in the presence of alterations of LV tissue motion. To this aim, the problem is solved numerically and the global force exchanged between blood flow and LV boundaries is computed by volume integration. We also introduce a simplified analytical model, based on global conservation laws, to estimate hemodynamic forces from the knowledge of LV tissue information commonly available in cardiac imaging. Numerical results show that the normal intraventricular gradients feature a deep brief suction at early diastolic filling and a persistent thrust during systolic ejection. In presence of abnormalities of the wall motion, the loss of time synchrony is more relevant than the loss of spatial uniformity in modifying the normal pressure gradient spatiotemporal pattern. The main findings are reproduced in the integral model, which represents a possible easy approach for integrating fluid dynamics evaluations in the clinical examination.

  15. Altered Hemodynamics Associated with Pathogenesis of the Vertebral Artery Dissecting Aneurysms

    Directory of Open Access Journals (Sweden)

    Akira Kurata

    2012-01-01

    Full Text Available The etiology of the vertebral dissecting aneurysms is largely unknown, and they frequently occurs in relatively healthy young men. Objectives and Methods. A series of 57 consecutive cases defined by angiography were evaluated with regard to deviation in the course of the affected and contralateral vertebral arteries. Division was into 3 types: Type I without any deviation, Type II with mild-to-moderate deviation but not over the midline; and Type III with marked deviation over to the contralateral side beyond the midline. Results. The most frequent type of VA running was Type III for the affected and Type I nonaffected side, with this being found in all 17 patients except one. All of the Type III dissections occurred just proximal to a tortuous portion, while in cases with Type-I- and Type-II-affected sides, the majority (33 of 39 occurred near the union of the vertebral artery. In 10 of 57, a non-dominant side was affected, all except one being of Type I or II. With 12 recent patients assessed angiographically in detail for hemodynamics, eleven patients showed contrast material retrograde inflowing into the pseudolumen from the distal portion of the dissection site. Turbulent blood flow was recognized in all of these patients with retrograde inflow. Conclusions. Turbulent blood flow is one etiology of vertebral artery dissection aneurysms, with the sites in the majority of the cases being just proximal to a tortuous portion or union of vessels. In cases with dissection proximal to the tortuous course of the vertebral artery, retrograde inflow will occur more frequently than antegrade, which should be taken into account in designing therapeutic strategies.

  16. The Effect of Neuraxial Anesthesia on Maternal Cerebral Hemodynamics

    NARCIS (Netherlands)

    Postma, Ineke R.; van Veen, Teelkien R.; Mears, Scott L.; Zeeman, Gerda G.; Haeri, Sina; Belfort, Michael A.

    2014-01-01

    Objective Neuraxial anesthesia is known to reduce sympathetic tone and mean arterial pressure. Effects on cerebral hemodynamics in pregnancy are not well known. We hypothesize that cerebral hemodynamic parameters will change with respect to baseline following regional analgesia/anesthesia. Study

  17. Advanced Hemodynamic Management in Patients with Septic Shock

    Science.gov (United States)

    Huber, Wolfgang; Nierhaus, Axel; Kluge, Stefan; Reuter, Daniel A.; Wagner, Julia Y.

    2016-01-01

    In patients with sepsis and septic shock, the hemodynamic management in both early and later phases of these “organ dysfunction syndromes” is a key therapeutic component. It needs, however, to be differentiated between “early goal-directed therapy” (EGDT) as proposed for the first 6 hours of emergency department treatment by Rivers et al. in 2001 and “hemodynamic management” using advanced hemodynamic monitoring in the intensive care unit (ICU). Recent large trials demonstrated that nowadays protocolized EGDT does not seem to be superior to “usual care” in terms of a reduction in mortality in emergency department patients with early identified septic shock who promptly receive antibiotic therapy and fluid resuscitation. “Hemodynamic management” comprises (a) making the diagnosis of septic shock as one differential diagnosis of circulatory shock, (b) assessing the hemodynamic status including the identification of therapeutic conflicts, and (c) guiding therapeutic interventions. We propose two algorithms for hemodynamic management using transpulmonary thermodilution-derived variables aiming to optimize the cardiocirculatory and pulmonary status in adult ICU patients with septic shock. The complexity and heterogeneity of patients with septic shock implies that individualized approaches for hemodynamic management are mandatory. Defining individual hemodynamic target values for patients with septic shock in different phases of the disease must be the focus of future studies. PMID:27703980

  18. The Effect of Neuraxial Anesthesia on Maternal Cerebral Hemodynamics

    NARCIS (Netherlands)

    Postma, Ineke R.; van Veen, Teelkien R.; Mears, Scott L.; Zeeman, Gerda G.; Haeri, Sina; Belfort, Michael A.

    2014-01-01

    Objective Neuraxial anesthesia is known to reduce sympathetic tone and mean arterial pressure. Effects on cerebral hemodynamics in pregnancy are not well known. We hypothesize that cerebral hemodynamic parameters will change with respect to baseline following regional analgesia/anesthesia. Study Des

  19. Hemodynamic Disorders in Explosive Mine Injury: Experimental Study

    OpenAIRE

    V. N Yelsky; G. K. Krivobok; A. N. Talalayenko; A. A. Redko; A. Yu. Kryuk

    2005-01-01

    The authors have studied hemodynamic features in explosive mine injury in the presence or absence of a preliminary exposure to premorbid mining factors. A combined influence of premorbid mining factors following an explosive mine injury has been ascertained to induce more severe systemic and cerebral hemodynamic disorders than an isolated explosive mine injury.

  20. Non-invasive assessment of maternal hemodynamics in early pregnancy

    NARCIS (Netherlands)

    van der Graaf, Anne Marijn; Zeeman, Gerda G.; Groen, Henk; Roberts, Claire; Dekker, Gus A.

    2013-01-01

    Objectives: Non-invasive assessment of maternal hemodynamics in early pregnancy may be promising in evaluating maternal hemodynamic (mal)adaptation to pregnancy. We explored usage of applanation tonometry and Doppler ultrasound for assessment of cardiac output (CO), systemic vascular resistance (SVR

  1. Contrast material and radiation dose reduction strategy for triple-rule-out cardiac CT angiography: feasibility study of non-ECG-gated low kVp scan of the whole chest following coronary CT angiography.

    Science.gov (United States)

    Kidoh, Masafumi; Nakaura, Takeshi; Nakamura, Shinichi; Namimoto, Tomohiro; Nozaki, Toshimitsu; Sakaino, Naritsugu; Harada, Kazunori; Yamashita, Yasuyuki

    2014-12-01

    Dedicated coronary computed tomography (CT) scan has been proven to be an accurate diagnostic modality in evaluating coronary artery disease. A second phase scan starting immediately after the coronary CT scan might enable visualization of the different vascular territories of the entire chest. To investigate the feasibility of a contrast material and radiation dose reduction triple-rule-out (TRO) CT angiography (CTA) protocol with serial non-ECG-gated low kVp scan of the whole chest, which utilizes a recirculated contrast agent. Thirty patients were scanned with the new TRO-CTA protocol; after the coronary scan with retrospective ECG-gating, non-ECG-gated whole-chest CTA was performed at 80 kVp to evaluate aortic arch (AAr) and pulmonary trunk (PT). Another 30 patients were scanned by our conventional TRO-CTA protocol at 120 kVp with retrospective ECG-gating. We compared the estimated effective dose (ED), contrast material (CM) dose, contrast-to-noise ratio (CNR) of the ascending aorta (AAo), and the rate of patients who could achieve adequate attenuation of the AAr and PT between the two protocols. The total ED of the new TRO-CTA protocol was 29.6% lower than that of the conventional protocol (P TRO-CTA protocol was significantly lower than in the conventional protocol (60.1 ± 9.6 mL vs. 91.8 ± 22.6 mL, P TRO-CTA protocol than with the conventional protocol (P 0.05). The new TRO-CTA protocol can reduce the total dose of radiation and the contrast dose and yield adequate vascular enhancement compared with the conventional protocol. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  2. Patient-specific structural effects on hemodynamics in the ischemic lower limb artery

    Science.gov (United States)

    Xu, Pengcheng; Liu, Xin; Song, Qi; Chen, Guishan; Wang, Defeng; Zhang, Heye; Yan, Li; Liu, Dan; Huang, Wenhua

    2016-12-01

    Lower limb peripheral artery disease is a prevalent chronic non-communicable disease without obvious symptoms. However, the effect of ischemic lower limb peripheral arteries on hemodynamics remains unclear. In this study, we investigated the variation of the hemodynamics caused by patient-specific structural artery characteristics. Computational fluid dynamic simulations were performed on seven lower limb (including superficial femoral, deep femoral and popliteal) artery models that were reconstructed from magnetic resonance imaging. We found that increased wall shear stress (WSS) was mainly caused by the increasing severity of stenosis, bending, and branching. Our results showed that the increase in the WSS value at a stenosis at the bifurcation was 2.7 Pa. In contrast, the isolated stenosis and branch caused a WSS increase of 0.7 Pa and 0.5 Pa, respectively. The WSS in the narrow popliteal artery was more sensitive to a reduction in radius. Our results also demonstrate that the distribution of the velocity and pressure gradient are highly structurally related. At last, Ultrasound Doppler velocimeter measured result was presented as a validation. In conclusion, the distribution of hemodynamics may serve as a supplement for clinical decision-making to prevent the occurrence of a morbid or mortal ischemic event.

  3. Numerical predictions of hemodynamics following surgeries in cerebral aneurysms

    Science.gov (United States)

    Rayz, Vitaliy; Lawton, Michael; Boussel, Loic; Leach, Joseph; Acevedo, Gabriel; Halbach, Van; Saloner, David

    2014-11-01

    Large cerebral aneurysms present a danger of rupture or brain compression. In some cases, clinicians may attempt to change the pathological hemodynamics in order to inhibit disease progression. This can be achieved by changing the vascular geometry with an open surgery or by deploying a stent-like flow diverter device. Patient-specific CFD models can help evaluate treatment options by predicting flow regions that are likely to become occupied by thrombus (clot) following the procedure. In this study, alternative flow scenarios were modeled for several patients who underwent surgical treatment. Patient-specific geometries and flow boundary conditions were obtained from magnetic resonance angiography and velocimetry data. The Navier-Stokes equations were solved with a finite volume solver Fluent. A porous media approach was used to model flow-diverter devices. The advection-diffusion equation was solved in order to simulate contrast agent transport and the results were used to evaluate flow residence time changes. Thrombus layering was predicted in regions characterized by reduced velocities and shear stresses as well as increased flow residence time. The simulations indicated surgical options that could result in occlusion of vital arteries with thrombus. Numerical results were compared to experimental and clinical MRI data. The results demonstrate that image-based CFD models may help improve the outcome of surgeries in cerebral aneurysms. acknowledge R01HL115267.

  4. Monitoring changes in hemodynamics following optogenetic stimulation

    Science.gov (United States)

    Frye, Seth

    The brain is composed of billions of neurons, all of which connected through a vast network. After years of study and applications of different technologies and techniques, there are still more questions than answers when it comes to the fundamental functions of the brain. This project aims to provide a new tool which can be used to gain a better understanding of the fundamental mechanisms that govern neurological processes inside the brain. In order for neural networks to operate, blood has to be supplied through neighboring blood vessels. As such, the increase or decrease in the blood supply has been used as an indicator of neural activity. The neural activity and blood supply relationship is known as neural vasculature coupling. Monitoring the hemodynamics is used as an indicator of neurological activity, but the causal relationship is an area of current research. Gaining a better understanding of the coupling of neural activity and the surrounding vasculature provides a more accurate methodology to evaluate regional neural activity. The new optical technology applied in this project provides a set of tools to both stimulate and monitor this coupling relationship. Optogenetics provides the capability of stimulating neural activity using specific wavelengths of light. Essentially this tool allows for the direct stimulation of networks of neurons by simply shining one color of light onto the brain. Optical Coherence Tomography (OCT), another new optical technology applied in this project, can record volumetric images of blood vessels and flow using only infrared light. The combination of the two optical technologies is then capable of stimulating neural activity and monitoring the hemodynamic response inside the brain using only light. As a result of this project we have successfully demonstrated the capability of both stimulating and imaging the brain using new optical technologies. The optical stimulation of neural activity has evoked a direct hemodynamic effect

  5. Comparing the Rates of Dopamine Hemodynamic Effect Onset after Infusion through Peripheral Veins in Three Regions

    Directory of Open Access Journals (Sweden)

    Deokkyu Kim

    2017-02-01

    Full Text Available Background Dopamine is an inotropic agent that is often selected for continuous infusion. For hemodynamic stability, the rate of infusion is controlled in the range of 5-15 μg/kg/min. This study aimed to compare the time intervals from the administration of dopamine to the onset of its hemodynamic effects when dopamine was administered through three different peripheral veins (the cephalic vein [CV], the great saphenous vein [GSV], and the external jugular vein [EJV]. Methods Patients in group 1, group 2, and group 3 received dopamine infusions in the CV, GSV, and EJV, respectively. A noninvasive continuous cardiac output monitor (NICCOMO™, Medis, Ilmenau, Germany was used to assess cardiac output (CO and systemic vascular resistance (SVR. Six minutes after intubation, baseline heart rate (HR, systolic blood pressure (BP, diastolic BP, mean arterial pressure (MAP, CO, and SVR values were recorded and dopamine infusion was initiated at a dose of 10 μg/kg/min. Hemodynamic changes at 0, 4, 8, 12, and 15 minutes postinfusion were recorded. Results No statistically significant differences were observed among the three groups with respect to the rate of hemodynamic change. In all groups, systolic BP, diastolic BP, MAP, and SVR tended to increase after decreasing for the first 4 minutes; in contrast, HR and CO decreased until 8 minutes, after which they tended to reach a plateau. Conclusions For patients under general anesthesia receiving dopamine at 10 μg/kg/min, there were no clinical differences in the effect of dopamine administered through three different peripheral veins.

  6. Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants

    Science.gov (United States)

    Brown, Jonathan; Lopes, Augusto C.; Kunio, Mie; Kolachalama, Vijaya B.; Edelman, Elazer R.

    2016-01-01

    Background Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design. Methods and Results Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D ‘clouds’ of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively) to individual strut-wall configurations (average displacement error ~15 μm). This framework facilitated hemodynamic simulation (n = 1 vessel), showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent) flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors. Conclusion Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments. PMID:26906566

  7. Abnormal hemodynamic response to forepaw stimulation in rat brain after cocaine injection

    Science.gov (United States)

    Chen, Wei; Park, Kicheon; Choi, Jeonghun; Pan, Yingtian; Du, Congwu

    2015-03-01

    Simultaneous measurement of hemodynamics is of great importance to evaluate the brain functional changes induced by brain diseases such as drug addiction. Previously, we developed a multimodal-imaging platform (OFI) which combined laser speckle contrast imaging with multi-wavelength imaging to simultaneously characterize the changes in cerebral blood flow (CBF), oxygenated- and deoxygenated- hemoglobin (HbO and HbR) from animal brain. Recently, we upgraded our OFI system that enables detection of hemodynamic changes in response to forepaw electrical stimulation to study potential brain activity changes elicited by cocaine. The improvement includes 1) high sensitivity to detect the cortical response to single forepaw electrical stimulation; 2) high temporal resolution (i.e., 16Hz/channel) to resolve dynamic variations in drug-delivery study; 3) high spatial resolution to separate the stimulation-evoked hemodynamic changes in vascular compartments from those in tissue. The system was validated by imaging the hemodynamic responses to the forepaw-stimulations in the somatosensory cortex of cocaine-treated rats. The stimulations and acquisitions were conducted every 2min over 40min, i.e., from 10min before (baseline) to 30min after cocaine challenge. Our results show that the HbO response decreased first (at ~4min) followed by the decrease of HbR response (at ~6min) after cocaine, and both did not fully recovered for over 30min. Interestingly, while CBF decreased at 4min, it partially recovered at 18min after cocaine administration. The results indicate the heterogeneity of cocaine's effects on vasculature and tissue metabolism, demonstrating the unique capability of optical imaging for brain functional studies.

  8. Central and peripheral hemodynamics in exercising humans

    DEFF Research Database (Denmark)

    Calbet, J A L; González-Alonso, J; Helge, J W

    2015-01-01

    In humans, arm exercise is known to elicit larger increases in arterial blood pressure (BP) than leg exercise. However, the precise regulation of regional vascular conductances (VC) for the distribution of cardiac output with exercise intensity remains unknown. Hemodynamic responses were assessed...... during incremental upright arm cranking (AC) and leg pedalling (LP) to exhaustion (Wmax ) in nine males. Systemic VC, peak cardiac output (Qpeak ) (indocyanine green) and stroke volume (SV) were 18%, 23%, and 20% lower during AC than LP. The mean BP, the rate-pressure product and the associated...... perfusion pressure to increase O2 delivery, allowing a similar peak VO2 per kg of muscle mass in both extremities. In summary, despite a lower Qpeak during arm cranking the cardiovascular strain is much higher than during leg pedalling. The adjustments of regional conductances during incremental exercise...

  9. [Myocardial contractility and hemodynamics in hypothyroidism].

    Science.gov (United States)

    Selivonenko, V G

    1977-01-01

    The author determined the phasic structure of the systole of the left ventricle by the method of polycardiography and hemodynamics in 20 patients suffering from hypothyrodism. Blood plasma and erythrocyte electrolytes were examined at the same time. Patients with hypothyroidism displayed a phasic syndrome of hypodynamia and a marked correlation between the phase of the synchronous contraction, the period of ejection, the strength of contraction of the left ventricle and the electrolyte content. Sodium and magnesium produced the greatest influence on the phasic structure of the systole; potassium and calcium had a lesser effect. The heart stroke volume diminished; as to the cardiac index, expenditure of the energy of cardiac contractions directed to the maintenance of movement of 1 litre of the minute blood volume; the external work, and the peripheral vascular resistance displayed no significant change.

  10. Red wine, arterial stiffness and central hemodynamics.

    Science.gov (United States)

    Karatzi, Kalliopi; Papaioannou, Theodore G; Papamichael, Christos; Lekakis, John; Stefanadis, Christodoulos; Zampelas, Antonis

    2009-01-01

    Red wine is considered to reduce cardiovascular risk and decrease peripheral systolic and diastolic blood pressure. Central aortic pressures are often more sensitive clinical and prognostic factors than peripheral pressures, while arterial stiffness is an independent prognostic factor for cardiovascular events. Great efforts are being made to find natural sources of improving health. In order to clarify the mechanisms under which a widely used drink, like red wine, is affecting heart and vessels, we aimed to review the available data regarding the effects of red wine on arterial stiffness, wave reflections and central blood pressures. The effect of red wine on central hemodynamics has been poorly explored with divergent results. Possible consequences of acute and long-term intake on arterial stiffness, wave reflections and central pressures are not clear. This might make someone skeptical when suggesting the consumption of a glass of red wine, although its cardioprotective actions (when moderately consumed) are already shown from epidemiological studies.

  11. 10.1.Heart function and hemodynamics

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930252 Pathophysiological effects oftranscoronary chemical ablation in dogs.QI Xi-angqian (齐向前),et al.Cardiovasc Instit &Fuwai Hosp,CAMS,Beijing.Chin Cir J 1992;7(6):567—569.This study was designed to evaluate thepathophysiologic changes induced by intracoro-nary ethanol (ICE) in normal dogs.CK—MBactivity,ECG,hemodynamics,myocardialnecrosis size and histologic changes resultingfrom ICE were observed.In anesthetized dogs,0.4~0.6 ml (group A,n=9) and 1.0~1.2 ml(group B,n=9) of 95% ethanol were injectedinto the diagonal branch of the lelt anterior de-

  12. Large eddy simulation of powered Fontan hemodynamics.

    Science.gov (United States)

    Delorme, Y; Anupindi, K; Kerlo, A E; Shetty, D; Rodefeld, M; Chen, J; Frankel, S

    2013-01-18

    Children born with univentricular heart disease typically must undergo three open heart surgeries within the first 2-3 years of life to eventually establish the Fontan circulation. In that case the single working ventricle pumps oxygenated blood to the body and blood returns to the lungs flowing passively through the Total Cavopulmonary Connection (TCPC) rather than being actively pumped by a subpulmonary ventricle. The TCPC is a direct surgical connection between the superior and inferior vena cava and the left and right pulmonary arteries. We have postulated that a mechanical pump inserted into this circulation providing a 3-5 mmHg pressure augmentation will reestablish bi-ventricular physiology serving as a bridge-to-recovery, bridge-to-transplant or destination therapy as a "biventricular Fontan" circulation. The Viscous Impeller Pump (VIP) has been proposed by our group as such an assist device. It is situated in the center of the 4-way TCPC intersection and spins pulling blood from the vena cavae and pushing it into the pulmonary arteries. We hypothesized that Large Eddy Simulation (LES) using high-order numerical methods are needed to capture unsteady powered and unpowered Fontan hemodynamics. Inclusion of a mechanical pump into the CFD further complicates matters due to the need to account for rotating machinery. In this study, we focus on predictions from an in-house high-order LES code (WenoHemo(TM)) for unpowered and VIP-powered idealized TCPC hemodynamics with quantitative comparisons to Stereoscopic Particle Imaging Velocimetry (SPIV) measurements. Results are presented for both instantaneous flow structures and statistical data. Simulations show good qualitative and quantitative agreement with measured data.

  13. Supplementary Material for: Global expression differences and tissue specific expression differences in rice evolution result in two contrasting types of differentially expressed genes

    KAUST Repository

    Horiuchi, Youko

    2015-01-01

    -eQTLs. Expression evolution of changed-tissues DE genes was rapid in tissue specifically expressed genes and those rapidly evolved changed-tissues DE genes were regulated not by cis-eQTLs, but by complicated trans-eQTLs. Conclusions Global DE genes and changed-tissues DE genes had contrasting characteristics. The two contrasting types of DE genes provide possible explanations for the previous controversial conclusions about the relationships between molecular evolution and expression evolution of genes in different species, and the relationship between expression breadth and expression conservation in evolution.

  14. Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now

    Energy Technology Data Exchange (ETDEWEB)

    Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Banfi, Giuseppe [IRCCS Istituto Ortopedico Galeazzi, Milano (Italy); Universita Vita-Salute San Raffaele, Milano (Italy); Aliprandi, Alberto [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); Mauri, Giovanni [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); Istituto Europeo di Oncologia, Unita di Radiologia Interventistica, Milano (Italy); Secchi, Francesco; Sardanelli, Francesco; Sconfienza, Luca Maria [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); IRCCS Policlinico San Donato, Servizio di Radiologia, San Donato, Milanese (Italy)

    2016-05-15

    Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation. (orig.)

  15. Linear superposition of sensory-evoked and ongoing cortical hemodynamics

    Directory of Open Access Journals (Sweden)

    Mohamad Saka

    2010-08-01

    Full Text Available Modern non-invasive brain imaging techniques utilise changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. To investigate this issue, 2-dimensional optical imaging spectroscopy was used to measure cortical hemodynamics in response to sensory stimuli in anaesthetised rodents Pre-stimulus cortical hemodynamics displayed spontaneous periodic fluctuations and as such, data from individual stimulus presentation trials were assigned to one of four groups depending on the phase angle of pre-stimulus hemodynamic fluctuations and averaged. This analysis revealed that sensory evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase angle of ongoing fluctuations at stimulus onset. To investigate the origin of this phenomenon, ‘null-trails’ were collected without stimulus presentation. Subtraction of phase averaged ‘null trials’ from their phase averaged stimulus-evoked counterparts resulted in four similar time series that resembled the mean stimulus-evoked response. These analyses suggest that linear superposition of evoked and ongoing cortical hemodynamic changes may be a property of the structure of inter-trial variability.

  16. Magnetic resonance imaging of regional hemodynamic and cerebrovascular recovery after lateral fluid-percussion brain injury in rats

    OpenAIRE

    2010-01-01

    Hemodynamic and cerebrovascular factors are crucially involved in secondary damage after traumatic brain injury (TBI). With magnetic resonance imaging, this study aimed to quantify regional cerebral blood flow (CBF) by arterial spin labeling and cerebral blood volume by using an intravascular contrast agent, during 14 days after lateral fluid-percussion injury (LFPI) in rats. Immunohistochemical analysis of vessel density was used to evaluate the contribution of vascular damage. Results show ...

  17. Dynamics of soil organic carbon fractions in olive groves in Andalusia (Southern Spain) in soils with contrasted parent material and under different management practices

    Science.gov (United States)

    Vicente-Vicente, Jose Luis; García-Ruiz, Roberto; Calero, Julio; Aranda, Victor

    2016-04-01

    Spain has 2.5 million hectares of olive groves, 60 % of which are situated in Andalusia (Southern Spain). The most common agricultural management consist of a conventional or reduced tillage combined with herbicides to eliminate weeds. This might lead to some ecological problems (e.g. erosion, soil nutrient and organic carbon losses). The recommended management consist of a plant cover of spontaneous herbaceous plant in the inter row of olive oil orchards which are usually mowed early in spring. In this study, we assessed the influence of: i) two soil managements: non-covered and weed-covered, and ii) soil parent material (carbonated and siliceous), on soil organic carbon (SOC) fractions. In addition, we assessed the existence of a saturation limit for the different SOC fractions by including calcareous and siliceous soils under natural vegetation. Weed-covered soils accumulated more total SOC than soils under the non-covered management and this was independent on the parent material type. Same was true for most of the SOC fractions. However, the relative proportion of the SOC fractions was not affected by the presence of weeds, but it was due to the parent material type; carbonated soils had more unprotected and physically protected SOC, whereas the siliceous soils were relatively enriched in biochemically protected pool. Otherwise, table 1 shows that the chemically protected SOC pool was best fit to a saturation function, especially in the siliceous plots. The other fractions were best fit to a linear function. Therefore, these results suggest that chemically protected pools are the only protected fractions which can be saturated considering the SOC in the natural vegetation soils as the SOC limit. Considering SOC levels in the weed-covered and non-covered managements of all protected fractions and their respective limits of total SOC, saturation deficits in the non-covered and weed-covered plots were 75% and 60% of total SOC, respectively. Table 1. Significance

  18. Advanced hemodynamic monitoring: principles and practice in neurocritical care.

    Science.gov (United States)

    Lazaridis, Christos

    2012-02-01

    Advanced hemodynamic monitoring is necessary for many patients with acute brain and/or spinal cord injury. Optimizing cerebral and systemic physiology requires multi-organ system function monitoring. Hemodynamic manipulations are cardinal among interventions to regulate cerebral perfusion pressure and cerebral blood flow. The pulmonary artery catheter is not any more the sole tool available; less invasive and potentially more accurate methodologies have been developed and employed in the operating room and among diverse critically ill populations. These include transpulmonary thermodilution, arterial pressure pulse contour, and waveform analysis and bedside critical care ultrasound. A thorough understanding of hemodynamics and of the available monitoring modalities is an essential skill for the neurointensivist.

  19. Magnetic resonance imaging of regional hemodynamic and cerebrovascular recovery after lateral fluid-percussion brain injury in rats.

    Science.gov (United States)

    Hayward, Nick Mark Edward Alexander; Tuunanen, Pasi I; Immonen, Riikka; Ndode-Ekane, Xavier Ekolle; Pitkänen, Asla; Gröhn, Olli

    2011-01-01

    Hemodynamic and cerebrovascular factors are crucially involved in secondary damage after traumatic brain injury (TBI). With magnetic resonance imaging, this study aimed to quantify regional cerebral blood flow (CBF) by arterial spin labeling and cerebral blood volume by using an intravascular contrast agent, during 14 days after lateral fluid-percussion injury (LFPI) in rats. Immunohistochemical analysis of vessel density was used to evaluate the contribution of vascular damage. Results show widespread ipsilateral and contralateral hypoperfusion, including both the cortex and the hippocampus bilaterally, as well as the ipsilateral thalamus. Hemodynamic unrest may partly be explained by an increase in blood vessel density over a period of 2 weeks in the ipsilateral hippocampus and perilesional cortex. Furthermore, three phases of perilesional alterations in CBF, progressing from hypoperfusion to normal and back to hypoperfusion within 2 weeks were shown for the first time in a rat TBI model. These three phases were similar to hemodynamic fluctuations reported in TBI patients. This makes it feasible to use LFPI in rats to study mechanisms behind hemodynamic changes and to explore novel therapeutic approaches for secondary brain damage after TBI.

  20. GENDER DISTINCTIONS OF MICROALBUMINURIA AND ITS RELATION TO INTRARENAL HEMODYNAMIC AND LEPTIN LEVEL IN ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. I. Podzolkov

    2012-01-01

    Full Text Available Aim. To assess an incidence of microalbuminuria (MAU depending on gender and its relation to intrarenal hemodynamic, glomerular filtration rate (GFR, and leptin serum level in essential hypertension (HT. Material and methods. 149 patients (61 men and 88 women, aged 49.4±7.1 years, body mass index 32.2±3.8 kg/m2 with HT degree 2-3 were examined. Clinical characteristics in men and women were comparable. Ultrasonography of intrarenal vessels was performed in all patients. GFR was calculated by isotope nephroangioscintigraphy. Leptin serum level was determined\\ by radioimmunoassay. MAU was detected by semiquantitative test. Results were processed with SPSS-11.0 software package. Results. MAU incidence was higher among female hypertensives in contrast to males: 40% vs 26% (p=0.056. Hypertensives with MAU of both genders demonstrated higher both resistance index (RI and pulsatility index (PI. Gender differences of both RI and PI in patients with MAU were highly significant (p<0.001 at all levels of arterial visualization (renal, segmental and interlobar. Female hypertensives with MAU had lower GFR (79.1±13.2 ml/min/1.73m2 than those without MAU (89.3±17.2 ml/min/1.73m2. Male hypertensives with MAU had higher GFR than those without MAU: 126±32.5 vs 105.4±16.7 ml/min/1.73m2, respectively. Serum leptin level in females with MAU was higher than this in female patients without MAU: 103.5±38.7 vs 76.7±46.4 ng/ml (p=0.04, respectively. Leptin levels did not differ in males with or without MAU. In males MAU positively correlated with GFR (r=0.372, р=0.003, where-as in females – correlation was negative (r=-0.34, р=0.02. Besides, in females MAU correlated with serum leptin level (r=0.48, p=0.01 Conclusion. Female hypertensives with MAU demonstrate more stable elevation of RI and PI in contrast to hypertensive males with MAU. MAU level correlates with GFR in opposite ways: in males positively whereas in females — negatively.

  1. Comparative Study of the Clonidin and Propranolol Effect in the Prevention of Hemodynamic Changes after Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    A. Moradi

    2009-04-01

    Full Text Available Introduction & Objective: ECT is an inevitable therapy for many of psychiatric patients. During ECT severe hemodynamic changes occur which may cause dangerous cardiovascular complications especially in elderly patients with cardiac disease and may lead to arrhythmia,ischemia and myocardial infarction. The purpose of this study was to show the effect of clonidin and propranolol on the prevention of hemodynamic changes following the ECT.Materials & Methods: This study was a controlled double blind clinical trial which was carried out on 31 patients ASA I, II hospitalized in psychiatry ward of Hamadan Sina hospital who were in need of ECT. In order to increase the accuracy of the study the personal factors on the drug metabolism were omitted and the chosen patients were given ECT three times separately with the interval of 48 hours. Two hours before every ECT clonidin (0.2 mg, propranolol (40 mg and placebo (vitamin c were administered and after each ECT the hemodynamic parameters including systolic blood pressure, diastolic blood pressure, rate pressure product and ECG were measured at certain intervals and recorded on information forms and then analyzed by SPSS 9 soft ware. Results: The result of this study showed that the average changes of hemodynamic parameters in different times occurred in all groups significantly(p<0.001. Following ECT, arrhythmia in control group has been plentiful in comparison with the other two groups, and the changes were statistically meaningful (p=0.001.Conclusion: We concluded that the modifying hemodynamic changes and decrease of arrhythmia taking the drugs in comparison with placebo have been more effective and of the two drugs, propranolol has been more effective on the prevention of hemodynamic changes after ECT.

  2. Heart and aortic baroreceptors: operation in providing hemodynamic processes in cardiovascular system

    Directory of Open Access Journals (Sweden)

    Mikhail Y. Rudenko

    2013-11-01

    Full Text Available Aims Up to the present, ECGs have been classified on the basis of the analysis of the ECG curve shape. But this made impossible to classify many ECG shapes. The most promising methods for the classification must evaluate each of the 10 cardiac cycle phases both by their functions and hemodynamic parameters. The aim hereof is to develop the new classification principles for all possible ECG shape variations. Materials and methods The heart cycle phase analysis method is used to calculate the hemodynamic parameters in each of 10 phases, like the phase-related blood volumes and the level of contraction of the corresponding cardiovascular musculature determining its function dynamics in the cardiac cycle phase structure related to the compensation mechanism for maintaining normal hemodynamics. Results An ECG phase changes periodic table consisting of 10 groups of the actual ECG curves typical for the corresponding pathologies is proposed. Each group contains 4 levels of characteristic phase changes. Conclusion The ECG phase changes periodic table is the first attempt to classify the great variety of the ECG shapes. In this case the proposed system requires further investigations. It has been demonstrated that the theoretical concept of the table is in compliance with practice. Further it is planned to improve characteristics of every group and every level.

  3. A computer-based matrix for rapid calculation of pulmonary hemodynamic parameters in congenital heart disease

    Directory of Open Access Journals (Sweden)

    Lopes Antonio

    2009-01-01

    Full Text Available Background : In patients with congenital heart disease undergoing cardiac catheterization for hemodynamic purposes, parameter estimation by the indirect Fick method using a single predicted value of oxygen consumption has been a matter of criticism. Objective : We developed a computer-based routine for rapid estimation of replicate hemodynamic parameters using multiple predicted values of oxygen consumption. Materials and Methods : Using Microsoft ® Excel facilities, we constructed a matrix containing 5 models (equations for prediction of oxygen consumption, and all additional formulas needed to obtain replicate estimates of hemodynamic parameters. Results : By entering data from 65 patients with ventricular septal defects, aged 1 month to 8 years, it was possible to obtain multiple predictions for oxygen consumption, with clear between-age groups ( P < .001 and between-methods ( P < .001 differences. Using these predictions in the individual patient, it was possible to obtain the upper and lower limits of a likely range for any given parameter, which made estimation more realistic. Conclusion : The organized matrix allows for rapid obtainment of replicate parameter estimates, without error due to exhaustive calculations.

  4. Hemodynamic changes during robotic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Vanlal Darlong

    2012-01-01

    Full Text Available Background: Effect on hemodynamic changes and experience of robot-assisted laparoscopic radical prostatectomy (RALRP in steep Trendelenburg position (45° with high-pressure CO 2 pneumoperitoneum is very limited. Therefore, we planned this prospective clinical trial to study the effect of steep Tredelenburg position with high-pressure CO 2 pneumoperitoneum on hemodynamic parameters in a patient undergoing RALRP using FloTrac/Vigileo™1.10. Methods: After ethical approval and informed consent, 15 patients scheduled for RALRP were included in the study. In the operation room, after attaching standard monitors, the radial artery was cannulated. Anesthesia was induced with fentanyl (2 μg/kg and thiopentone (4-7 mg/kg, and tracheal intubation was facilitated by vecuronium bromide (0.1 mg/kg. The patient′s right internal jugular vein was cannulated and the Pre Sep™ central venous oximetry catheter was connected to it. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide and intermittent boluses of vecuronium. Intermittent positive-pressure ventilation was provided to maintain normocapnea. After CO 2 pneumoperitoneum, position of the patient was gradually changed to 45° Trendelenburg over 5 min. The robot was then docked and the robot-assisted surgery started. Intraoperative monitoring included central venous pressure (CVP, stroke volume (SV, stroke volume variation (SVV, cardiac output (CO, cardiac index (CI and central venous oxygen saturation (ScvO 2 . Results: After induction of anesthesia, heart rate (HR, SV, CO and CI were decreased significantly from the baseline value (P>0.05. SV, CO and CI further decreased significantly after creating pneumoperitoneum (P>0.05. At the 45° Trendelenburg position, HR, SV, CO and CI were significantly decreased compared with baseline. Thereafter, CO and CI were persistently low throughout the 45° Trendelenburg position (P=0.001. HR at 20 min and 1 h, SV and mean arterial blood pressure

  5. HEMODYNAMIC EFFECTS OF CARVEDILOL IN PATIENTS WITH ARTERIAL HYPERTENSION

    Directory of Open Access Journals (Sweden)

    L. I. Markova

    2006-01-01

    Full Text Available Aim. To evaluate the influence of carvedilol (Talliton, Egis, Hungary on daily profile of blood pressure (BP, anatomical and functional conditions of left ventricle (LV and cerebral circulation in patients with arterial hypertension (AH, stage II-III. Material and methods. 30 patients (10 men, 20 women, average age 51,9±7,9 y.o. with AH II-III stage ( RSSC,2004 and with initially affected daily profile of BP, cerebral circulation, anatomical and functional disorders of LV took carvedilol 25-75 mg/d during 6 months. Hemodynamics was estimated by ambulatory BP monitoring, Doppler Echocardiography, and ultrasound Dopplerography of extra cranial vessels. Results. A normalizing effect of carvedilol on abnormal daily profile of BP and cerebral circulation was determined. The treatment resulted in the regress of LV hypertrophy with predominant reduction of interventricular septum thickness and also the transformation of concentrical LV hypertrophy in excentrical one. Conclusion. Long-term therapy with carvedilol in patients with AH II-III stage provides a stable BP control and cardioprotective effect, improves cerebral circulation.

  6. OBSTRUCTIVE SLEEP APNEA: THE STATE OF CEREBRAL HEMODYNAMIC RESERVE

    Directory of Open Access Journals (Sweden)

    N. L. Kunelskaya

    2016-01-01

    Full Text Available Background: Individuals with obstructive  sleep apnea syndrome (OSAS have an increased risk of disabling disorders of the cardiovascular system, including  stroke.  The  mechanisms   of OSAS effects on cerebral blood flow and cerebral vascular autoregulation have not been clear enough. Aim: To study characteristics of cerebral blood flow in patients  with OSAS and the effect of CPAP therapy on cerebral hemodynamic reserve. Materials and  methods: One  hundred and  two  patients with various OSAS severity (61 male  and  41 female and  20 healthy  volunteers  participated in the study. We performed  ultrasound assessment of cerebral  blood  flow with functional  tests  and calculated  reactivity indices. Results: With more severe OSAS, no significant differences in cerebral vascular reactivity compared to the control group were  registered. However, there  was a trend  to some  decrease  in the  index of constriction  and dilation  in the  vertebral  arteries  and  the  basilar artery, as well as to its increase in the middle cerebral artery in severe and moderate OSAS. The index of vasomotor  reactivity of cerebral  arteries was significantly (р < 0.05 lower in patients with  severe  OSAS:  for vertebral  arteries,  up  to 38.9 ± 8.5 and for basilar artery, up to 36.8 ± 15.7, compared to  the  control  group  (52.1 ± 9.8 and 50.1 ± 11.2, respectively. In patients who initiated CPAP therapy, there were no changes  in velosity, resistance  and  reactivity parameters of cerebral vessels after 2 months. Conclusion: We were able to  confirm a significant  impairment  of cerebral vascular autoregulation  in patients  with severe OSAS, predominantly in the posterior circulatory region. CPAP-therapy of 2 months'  duration  did not lead to restoration  of cerebral hemodynamic reserve.

  7. New approach to intracardiac hemodynamic measurements in small animals

    DEFF Research Database (Denmark)

    Eskesen, Kristian; Olsen, Niels T; Dimaano, Veronica L

    2012-01-01

    Invasive measurements of intracardiac hemodynamics in animal models have allowed important advances in the understanding of cardiac disease. Currently they are performed either through a carotid arteriotomy or via a thoracotomy and apical insertion. Both of these techniques have disadvantages...

  8. Aortic endograft sizing in trauma patients with hemodynamic instability

    NARCIS (Netherlands)

    Jonker, Frederik H. W.; Verhagen, Hence J. M.; Mojibian, Hamid; Davis, Kimberly A.; Moll, Frans L.; Muhs, Bart E.

    2010-01-01

    Objectives: To investigate changes in aortic diameter in hemodynamically unstable trauma patients and the implications for sizing of thoracic endovascular aortic repair (TEVAR) in patients with traumatic thoracic aortic injury (TTAI). Methods: We retrospectively evaluated all trauma patients that we

  9. Radiation protection in hemodynamics work process: the look of the multidisciplinary team; Protecao radiologica no processo de trabalho em hemodinamica: o olhar da equipe multidisciplinar

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Laurete Medeiros; Klauberg, Daniela; Huhn, Andrea; Melo, Juliana Almeida Coelho de, E-mail: laurete@ifsc.edu.br, E-mail: danielaklauberg@hotmail.com, E-mail: andrea.huhn@ifsc.edu.br, E-mail: julianac@ifsc.edu.br [Instituto Federal de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

    2014-07-01

    The study was conducted in a hemodynamics service of a public hospital in Florianopolis, SC, Brazil. Qualitative research with the participation of 13 professionals from a multidisciplinary team: doctors, technicians, technologists in radiology and nurses. The research material was extracted from the observations, semi-structured interviews and documentary analysis. The responses were grouped into three categories relating to: training of hemodynamic professionals and the perception of radiological protection in the work process; occupational exposure and safety of the professionals of Hemodynamics; and continuing education in hemodynamic service. Professionals are daily exposed to ionizing radiation, and for being long procedures, lead to high levels of exposure in workers. In hemodynamic services the risk of biological effects are cumulative, because radiodiagnostic procedures include issuing the higher doses of ionizing radiation in which the personnel exposure is critical. The workforce in the service researched mostly consists of technical professionals who reported little knowledge of radiation protection and ionizing radiation and that this issue was not addressed during their training. However, despite mention little knowledge about radiological protection, participants demonstrated understand the biological effects, especially with regard to pathologies caused by frequent exposure without protection to ionizing radiation. These professionals said they have no knowledge of the proper use of radiological protection equipment and the dosimeter, and that the institution does not provide all individual protective equipment required for the procedures performed in the hemodynamic service. Permanent education in hemodynamic service is very important part in the work process, though, cited by participants as little effectiveness in the institution, even when the professionals show interest in the area. Knowledge of the team providing hemodynamic service calls

  10. Low-dose esmolol: hemodynamic response to endotracheal intubation in normotensive patients

    Directory of Open Access Journals (Sweden)

    Suresh Lakshmanappa

    2012-06-01

    Full Text Available Abstract Purpose: Endotracheal intubation is a frequently utilized and highly invasive component of anesthesia that is often accompanied by potentially harmful hemodynamic pressor responses. The purpose of this study was to investigate the efficiency of a single pre-induction 1 mg/kg bolus injection of esmolol for attenuating these hemodynamic responses to endotracheal intubation in normotensive patients. Material and methods: The study was composed of 100 randomly selected male and female patients between the ages of 18 and 60 that were scheduled for elective surgery and belonged to ASA grade I or II. Two minutes prior to intubation the control group received 10 mL of saline (n=50 and the experimental group received an injection of esmolol 1 mg/kg diluted to 10 mL (n=50. Heart rate (HR, systolic blood pressure (SBP, diastolic blood pressure (DBP, mean arterial pressure (MAP, and rate pressure product (RPP were compared to basal values before receiving medication (T-0, during pre-induction (T-1, induction (T-2, intubation (T-3, and post-intubation at 1 (T-4, 3 (T-6, 5 (T-8, and 10 (T-13 minutes. Results: Esmolol significantly attenuated the hemodynamic responses to endotracheal intubation at the majority of measured points. Attenuation of HR (10.8%, SBP (7.04%, DBP (3.99%, MAP (5%, and RPP (16.9% was observed in the esmolol group when compared to the control group values. Conclusions: A single pre-induction 1 mg/kg bolus injection of esmolol successfully attenuated the hemodynamic pressor response in normotensive patients. A significant attenuation of heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure was observed at the majority of measured time points in the esmolol administered group compared to the control group. [J Contemp Med 2012; 2(2.000: 69-76

  11. IMPACT OF THE ANTIVIRAL THERAPY ON CARDIAC HEMODYNAMICS IN PATIENTS WITH CHRONIC VIRAL HEPATITIS

    Directory of Open Access Journals (Sweden)

    M. V. Chistyakova

    2015-01-01

    Full Text Available Aim. To study the effect of antiviral therapy (AVT on some cardiac hemodynamic parameters in patients with chronic viral hepatitis (CVH.Material and methods. Segmental systolic and diastolic functions of the ventricles as well as global diastolic function were evaluated in 25 patients with CVH by pulsed tissue Doppler mapping and by the method of Doppler echocardiography, respectively. The blood flow speed and diameter of blood vessels in liver were determined by ultrasound Doppler. Cardiac hemodynamics was examined in all patients before and after AVT with interferon in combination with ribavirin with formation of persistent virological response. Healthy people (n=19 were included into control group.Results. Reduction in atrial and ventricular sizes, decrease in left ventricular mass, improvement of systolic function of both ventricles, as well as diastolic function of the left ventricle were found in patients with CVH after specific treatment. Reduction in hepatic arterial and portal blood flow speed and a total number of heart rhythm disorders were also observed. Therefore AVT in patients with CVH shows a positive impact on cardiac hemodynamics. Medium-strength correlation (r=0.31; p<0.05 was identified between Еm speed at fibrous ring of mitral valve and high viral load. Strong correlation (r=0.81; p<0.05 was also found between portal vein diameter and Sm speed at fibrous ring of tricuspid valve.Conclusion. Patients with CVH that do not receive AVT have worse prognosis and indicators of cardiac hemodynamics in comparison with patients who receive specific AVT.

  12. Hemodynamic challenge to early mobilization after cardiac surgery: A pilot study

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    Tiziano Cassina

    2016-01-01

    Full Text Available Background: Active mobilization is a key component in fast-track surgical strategies. Following major surgery, clinicians are often reluctant to mobilize patients arguing that circulatory homeostasis would be impaired as a result of myocardial stunning, fluid shift, and autonomic dysfunction. Aims: We examined the feasibility and safety of a mobilization protocol 12-24 h after elective cardiac surgery. Setting and Design: This observational study was performed in a tertiary nonacademic cardiovascular Intensive Care Unit. Materials and Methods: Over a 6-month period, we prospectively evaluated the hemodynamic response to a two-staged mobilization procedure in 53 consecutive patients. Before, during, and after the mobilization, hemodynamics parameters were recorded, including the central venous oxygen saturation (ScvO 2 , lactate concentrations, mean arterial pressure (MAP, heart rate (HR, right atrial pressure (RAP, and arterial oxygen saturation (SpO 2 . Any adverse events were documented. Results: All patients successfully completed the mobilization procedure. Compared with the supine position, mobilization induced significant increases in arterial lactate (34.6% [31.6%, 47.6%], P = 0.0022 along with reduction in RAP (−33% [−21%, −45%], P 10% and nine of them (17% required treatment. Hypotensive patients experienced a greater decrease in ScvO 2 (−18 ± 5% vs. −9 ± 4%, P = 0.004 with similar changes in RAP and HR. All hemodynamic parameters, but arterial lactate, recovered baseline values after resuming the horizontal position. Conclusions: Early mobilization after cardiac surgery appears to be a safe procedure as far as it is performed under close hemodynamic and clinical monitoring in an intensive care setting.

  13. Cerebral computed tomography angiography using a low tube voltage (80 kVp) and a moderate concentration of iodine contrast material: a quantitative and qualitative comparison with conventional computed tomography angiography.

    Science.gov (United States)

    Cho, Eun-Suk; Chung, Tae-Sub; Oh, Dae Kun; Choi, Hyun Seok; Suh, Sang Hyun; Lee, Hyeon-Kyeong; Lee, Kyung Hee

    2012-02-01

    To investigate the feasibility of an 80-kVp protocol using a moderate concentration contrast material (MC-CM) for cerebral computed tomography angiography by comparison with a conventional 120-kVp protocol using a high concentration contrast material (HC-CM). Attenuation values and signal-to-noise ratios (SNRs) were determined in a head phantom for 2 tube voltages (80 and 120 kVp) and 2 different iodine concentration contrast materials (HC-CM and MC-CM). Among 90 consecutive patients, 45 patients were scanned with 120 kVp and 150 mAs(eff) after administration of 70 mL of HC-CM (370 mg iodine [mgI]/mL), whereas the other 45 patients were scanned with 80 kVp and 370 mAs(eff) after administration of 70 mL of MC-CM (300 mgI/mL). The Hounsfield units (HU) of the internal carotid artery T junction, SNR, contrast-to-noise ratio (CNR), subjective degree of arterial enhancement, image noise, sharpness of the cerebral arterial boundary, and overall diagnostic image quality were compared between the 2 groups. The mean attenuation of the internal carotid artery T junction, SNR, and CNR was significantly higher in the 80 kVp with MC-CM group (379.2, 33.7, and 31.1 HU, respectively) than in the 120 kVp with HC-CM group (282.2, 31.1, and 27.2 HU, respectively). The 80-kVp protocol resulted in significantly higher score in arterial enhancement, sharpness of the cerebral arteries, and overall diagnostic image quality. The effective dose of 80 kVp (0.7 mSv) was 22.2% lower than that of 120 kVp (0.9 mSv). The use of 80 kVp with MC-CM improved arterial enhancement, SNR, and CNR and provided superior quality images using a smaller amount of iodine and a lower radiation dose than the conventional protocol of 120 kVp with HC-CM.

  14. Multimodal nanoparticulate bioimaging contrast agents.

    Science.gov (United States)

    Sharma, Parvesh; Singh, Amit; Brown, Scott C; Bengtsson, Niclas; Walter, Glenn A; Grobmyer, Stephen R; Iwakuma, Nobutaka; Santra, Swadeshmukul; Scott, Edward W; Moudgil, Brij M

    2010-01-01

    A wide variety of bioimaging techniques (e.g., ultrasound, computed X-ray tomography, magnetic resonance imaging (MRI), and positron emission tomography) are commonly employed for clinical diagnostics and scientific research. While all of these methods use a characteristic "energy-matter" interaction to provide specific details about biological processes, each modality differs from another in terms of spatial and temporal resolution, anatomical and molecular details, imaging depth, as well as the desirable material properties of contrast agents needed for augmented imaging. On many occasions, it is advantageous to apply multiple complimentary imaging modalities for faster and more accurate prognosis. Since most imaging modalities employ exogenous contrast agents to improve the signal-to-noise ratio, the development and use of multimodal contrast agents is considered to be highly advantageous for obtaining improved imagery from sought-after imaging modalities. Multimodal contrast agents offer improvements in patient care, and at the same time can reduce costs and enhance safety by limiting the number of contrast agent administrations required for imaging purposes. Herein, we describe the synthesis and characterization of nanoparticulate-based multimodal contrast agent for noninvasive bioimaging using MRI, optical, and photoacoustic tomography (PAT)-imaging modalities. The synthesis of these agents is described using microemulsions, which enable facile integration of the desired diversity of contrast agents and material components into a single entity.

  15. Central Hemodynamic Function in Miners with Thermal Injury

    Directory of Open Access Journals (Sweden)

    V. V. Moroz

    2008-01-01

    Full Text Available Objective: to study the specific features of central hemodynamic function in the acute phase of severe thermal injury (STI in miners who had a length of service of 10 years or more. Subjects and methods. A noninvasive study of central hemodynamics was conducted in 33 miners with severe thermal injury (a study group and 34 patients without a length of underground work who had the same condition (a control group. Both groups were matched by age and the nature and severity of thermal injuries. Central hemodynamics was evaluated by the following parameters: mean arterial blood, heart rate, stroke index (SI, cardiac index (CI, cardiac output (CO, specific vascular peripheral resistance (SVPR determined by Cubichek tetrapolar rheography. Results. The study indicated that on posttraumatic days 3—7, as compared with victims without a length of underground service, the miners had more pronounced central hemodynamic changes: decreases in CI, SI, and CO and an increase in SVPR. In the control group, from day 3, the hemodynamic changes were the following: increases in SI, SI, and CO and a decrease in SVPR. In the miners, the above features were attributable to the baseline central hemodynamic function. Conclusion. Thus, unlike the victims without a length of underground service, the miners with severe thermal injury develop more significant and prolonged central hemodynamic disorders. The detected differences during thermal injury are determined by the lowered reserve capacities of the cardiovascular system in miners due to the long-term exposure to poor working conditions, i. e. an underground service length of 10 years or more. Key words: thermal injury, miner, hemodynamics, type of circulation.

  16. Hemodynamics of patient-specific aorta-pulmonary shunt configurations

    OpenAIRE

    Pekkan, Kerem; Pişkin, Senol; Altın, H. Fırat; Yıldız, Okan; Bakır, İhsan

    2017-01-01

    Optimal hemodynamics in aorta-pulmonary shunt reconstruction is essential for improved post-operative recovery of the newborn congenital heart disease patient. However, prior to in vivo execution, the prediction of post-operative hemodynamics is extremely challenging due to the interplay of multiple confounding physiological factors. It is hypothesized that the post-operative performance of the surgical shunt can be predicted through computational blood flow simulations that consider patient ...

  17. Wireless Monitoring of Liver Hemodynamics In Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Akl, Tony [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL; Farquhar, Ethan [ORNL; Cote, Gerard L. [Texas A& M University

    2014-01-01

    Liver transplants have their highest technical failure rate in the first two weeks following surgery. Currently, there are limited devices for continuous, real-time monitoring of the graft. In this work, a three wavelengths system is presented that combines near-infrared spectroscopy and photoplethysmography with a processing method that can uniquely measure and separate the venous and arterial oxygen contributions. This strategy allows for the quantification of tissue oxygen consumption used to study hepatic metabolic activity and to relate it to tissue stress. The sensor is battery operated and communicates wirelessly with a data acquisition computer which provides the possibility of implantation provided sufficient miniaturization. In two in vivo porcine studies, the sensor tracked perfusion changes in hepatic tissue during vascular occlusions with a root mean square error (RMSE) of 0.135 mL/min/g of tissue. We show the possibility of using the pulsatile wave to measure the arterial oxygen saturation similar to pulse oximetry. The signal is also used to extract the venous oxygen saturation from the direct current (DC) levels. Arterial and venous oxygen saturation changes were measured with an RMSE of 2.19% and 1.39% respectively when no vascular occlusions were induced. This error increased to 2.82% and 3.83% when vascular occlusions were induced during hypoxia. These errors are similar to the resolution of a commercial oximetry catheter used as a reference. This work is the first realization of a wireless optical sensor for continuous monitoring of hepatic hemodynamics.

  18. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  19. EFFECT OF LEFT VENTRICULAR SYSTOLIC DYSFUNCTION ON CEREBRAL HEMODYNAMICS IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION (THE RESULTS OF OBSERVATIONAL STUDIES

    Directory of Open Access Journals (Sweden)

    V. E. Kulikov

    2015-12-01

    Full Text Available Aim. To study the effect of left ventricular (LV systolic dysfunction on cerebral hemodynamic in patients with ST segment elevation myocardial infarction (STEMI during acute period. Material and methods. Cerebral hemodynamics ultrasound assessment was performed in the extra-and intracranial vessels in 118 patients with STEMI. Results. Significant changes in cerebral hemodynamics were found in LV systolic dysfunction with ejection fraction (LVEF ≤40% due to hemispheric blood flow asymmetry in the middle cerebral artery (MCA as large as 45.1±6.7% with correlation coefficient r=-0.87. Compensation of cerebral blood flow was manifested in vasoconstriction or vasodilation (resistive index 0.63-0.76 and 0.49-0.43 c.u., respectively. Conclusion. A strong relationship between LV systolic dysfunction and cerebral hemodynamic was found in patients with STEMI. It was manifested in significant contralateral hemispheric blood flow asymmetry in MCA in patients with LVEF ≤40%. Reduction in cerebral blood flow velocity activated autoregulation mechanism in the form of vasoconstriction or vasodilation.

  20. Effect of one minimum alveolar concentration sevoflurane with and without fentanyl on hemodynamic response to laryngoscopy and tracheal intubation

    Directory of Open Access Journals (Sweden)

    Anwar Hoda

    2011-01-01

    Full Text Available Background : Drug combinations can be used for optimum obtundation of the hemodynamic response to tracheal intubation. The objective of this trial was to compare the hemodynamic response to laryngoscopy and tracheal intubation after administration of 2 μg/kg fentanyl bolus or a placebo with 2% end tidal sevoflurane at induction of anesthesia. Materials and Methods : A total of 70 surgical patients of either gender, age 18-45 years were selected for this double blind, randomized, placebo controlled trial, with 35 in each group. All patients received a standardized induction with thiopentone, atracurium, and an end tidal concentration of 1 minimum alveolar concentration (MAC sevoflurane. Heart rate and noninvasive blood pressure were compared to the baseline post induction and for seven minutes post intubation. Some adverse events were noted. Results : The maximum heart rate response was significantly less in the sevoflurane fentanyl group (15% vs. 22%. Significant difference between groups was observed in the systolic blood pressure at six minutes post intubation. Hemodynamic adverse events recorded were similar. Conclusion : Addition of 2 μg fentanyl bolus to 1 MAC sevoflurane anesthesia at induction attenuated the hemodynamic response to a maximum of 15% above baseline values.

  1. Usefulness of three-dimensional CT angiography (3D-CTA) with a single bolus injection of contrast material for the examination of intracranial and cervical arteries in cerebrovascular disease screening

    Energy Technology Data Exchange (ETDEWEB)

    Takamura, Yukio [Sapporo National Hospital (Japan); Tanooka, Atsushi; Morimoto, Shigefumi

    2001-05-01

    Three-dimensional CT angiography (3D-CTA) has been gaining wide acceptance as a clinically useful tool in the field of neurosurgery. The great diagnostic value of 3D-CTA for cerebral aneurysm or other cerebrovascular diseases has been well established. However, images of the intracranial and cervical arteries have not been obtained simultaneously because of the limitation of the scanning area and the need for contrast material. In order to use 3D-CTA to screen for cerebrovascular disease, we used a helical CT scan with an intravenous single bolus injection of contrast material to perform 3D-CTA of the intracranial and cervical arteries simultaneously. A spiral computed tomographic scan was performed with a Hispeed Advantage RP (General Electric). After injection of 150 ml of nonionized contrast material at a rate of 3 mm/sec in an antecubital vein, an axial computed tomographic scan (120 kV, 200 mA) of the cranial region was performed with a delay of 20-25 seconds after starting the injection. Section thickness was 1 mm with table increments of 1 mm per rotation. The scan volume included 20-30 mm above and below the sella turcica. An axial computed tomographic scan (120 kV, 190 mA) of the cervical region was performed with a delay of 30 seconds after completion of cranial CTA. Section thickness was 3 mm with table increments of 3 mm per rotation. Image reconstruction was carried out through surface rendering and maximum intensity projection processing. From November 1995 to August 1998, we used this technique to screen 218 consecutive outpatients for cerebrovascular disease. Unruptured cerebral aneurysms were found in 20 cases (9.2%). Atherosclerotic diseases of the cervical carotid artery were found in 58 cases (26.6%), as follows: carotid artery occlusion in 2 cases, carotid bifurcation stenosis in 22 cases, and intramural calcification of the internal carotid artery in 50 cases. Atherosclerotic diseases of the intracranial artery were found in 99 cases (45

  2. Wireless monitoring of liver hemodynamics in vivo.

    Directory of Open Access Journals (Sweden)

    Tony J Akl

    Full Text Available Liver transplants have their highest technical failure rate in the first two weeks following surgery. Currently, there are limited devices for continuous, real-time monitoring of the graft. In this work, a three wavelengths system is presented that combines near-infrared spectroscopy and photoplethysmography with a processing method that can uniquely measure and separate the venous and arterial oxygen contributions. This strategy allows for the quantification of tissue oxygen consumption used to study hepatic metabolic activity and to relate it to tissue stress. The sensor is battery operated and communicates wirelessly with a data acquisition computer which provides the possibility of implantation provided sufficient miniaturization. In two in vivo porcine studies, the sensor tracked perfusion changes in hepatic tissue during vascular occlusions with a root mean square error (RMSE of 0.135 mL/min/g of tissue. We show the possibility of using the pulsatile wave to measure the arterial oxygen saturation similar to pulse oximetry. The signal is also used to extract the venous oxygen saturation from the direct current (DC levels. Arterial and venous oxygen saturation changes were measured with an RMSE of 2.19% and 1.39% respectively when no vascular occlusions were induced. This error increased to 2.82% and 3.83% when vascular occlusions were induced during hypoxia. These errors are similar to the resolution of a commercial oximetry catheter used as a reference. This work is the first realization of a wireless optical sensor for continuous monitoring of hepatic hemodynamics.

  3. Hemodynamic monitoring in the intensive care unit: a Brazilian perspective

    Science.gov (United States)

    Dias, Fernando Suparregui; Rezende, Ederlon Alves de Carvalho; Mendes, Ciro Leite; Silva Jr., João Manoel; Sanches, Joel Lyra

    2014-01-01

    Objective In Brazil, there are no data on the preferences of intensivists regarding hemodynamic monitoring methods. The present study aimed to identify the methods used by national intensivists, the hemodynamic variables they consider important, the regional differences, the reasons for choosing a particular method, and the use of protocols and continued training. Methods National intensivists were invited to answer an electronic questionnaire during three intensive care events and later, through the Associação de Medicina Intensiva Brasileira portal, between March and October 2009. Demographic data and aspects related to the respondent preferences regarding hemodynamic monitoring were researched. Results In total, 211 professionals answered the questionnaire. Private hospitals showed higher availability of resources for hemodynamic monitoring than did public institutions. The pulmonary artery catheter was considered the most trusted by 56.9% of the respondents, followed by echocardiograms, at 22.3%. Cardiac output was considered the most important variable. Other variables also considered relevant were mixed/central venous oxygen saturation, pulmonary artery occlusion pressure, and right ventricular end-diastolic volume. Echocardiography was the most used method (64.5%), followed by pulmonary artery catheter (49.3%). Only half of respondents used treatment protocols, and 25% worked in continuing education programs in hemodynamic monitoring. Conclusion Hemodynamic monitoring has a greater availability in intensive care units of private institutions in Brazil. Echocardiography was the most used monitoring method, but the pulmonary artery catheter remains the most reliable. The implementation of treatment protocols and continuing education programs in hemodynamic monitoring in Brazil is still insufficient. PMID:25607264

  4. Computational Investigation of Hemodynamics in Fully Stenosed CABG

    Institute of Scientific and Technical Information of China (English)

    QIAOAi-ke; LIUYou-jun

    2004-01-01

    Coronary Artery Bypass Graft (CABG) is an important surgical treatment for critically stenosed arteries. Unfortunately restenosis always occurs after CABG surgery, which bring about surgery failure, lntimal thickening in the CABG distal anastomosis has been implicated as the major cause of restenosis and long-term graft failure. The nonuniform hemodynamics including disturbed flows, recirculation zones, oscillating wall shear stress, and long particle residence time were thought to be the possible etiologies. Numerical simulation was proved to be of great help and guidance meaning for the biofluid mechanics research and the CABG surgical plan. The present study was based on the hypothesis that the geometry configuration of CABG could greatly influence the hemodynamics in the vicinity of anastomosis. The hemodynamic features of two geometry models of end-to-side CABG were studied and compared. One simulated a conventional CABG with 1-way bypass graft, and the other simulated a modified CABG with symmetric 2-way bypass graft. The numerical investigations of hemodynamics in these two models with fully stenosed coronary arteries were accomplished using finite element method. The temporal and spatial distributions of hemodynamics were analyzed and compared. Results showed that the presence of symmetric 2-way bypass graft was of reasonable and favorable hemodynamics than 1-way bypass graft. The modified CABG model created a more hemodynamically efficient streamlined environment with higher mean and maximum axial velocities and lower radial velocities than the conventional 1-way model. Meanwhile, the symmetric 2-way bypass graft was featured with low pressure near the wall, high and uniform WSS in the host artery. All of these were favorable for inhibiting the development of intimal thickening, restenosis, and ultimate failure of the CABG, and it could considerably improve the flow conditions and decrease the probability of intimal hyperplasia and restenosis of CABG.

  5. Echocardiographic Evaluation of Hemodynamics in Neonates and Children

    Directory of Open Access Journals (Sweden)

    Yogen Singh

    2017-09-01

    Full Text Available Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by the clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of the urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload and cardiac output. The echocardiography has the ability to provide longitudinal functional assessment in real time, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children. It is indispensable in the management of patients with shock, pulmonary hypertension, and patent ductus arteriosus. The echocardiography is the gold standard diagnostic tool to assess hemodynamic stability in patients with pericardial effusion, cardiac tamponade, and cardiac abnormalities such as congenital heart defects or valvar disorders. The information from echocardiography can be used to provide targeted treatment in intensive care settings such as need of fluid resuscitation versus inotropic support, choosing appropriate inotrope or vasopressor, and in providing specific interventions such as selective pulmonary vasodilators in pulmonary hypertension. The physiological information gathered from echocardiography may help in making timely, accurate, and appropriate diagnosis and providing specific treatment in sick patients. There is no surprise that use of bedside point-of-care echocardiography is rapidly gaining interest among neonatologists and intensivists, and it is now being used in clinical decision making for patients with hemodynamic instability. Like any

  6. [Peculiarities of face regional hemodynamics in treatment of acute purulent jaw odontogenic periostitis].

    Science.gov (United States)

    Fedotov, S N; Sukhanov, A E; Konkina, M A; Iakovlev, V E

    2010-01-01

    53 patients were under observation with acute purulent jaw odontogenic periostitis. In 27 out of them after operation as drainage material strips of napkin were used, containing as the active components metronidazol, dimexide and sodium alginate. Curative process efficacy evaluation was done according to the data of hemodynamic study (determination of the artery's diameter, maximal systolic speed and index of circulatory resistance) of the magistral face arteries. It was established that in the group of patients with rational treatment blood circulation in face arterial vessels was restored most actively than in the control group with the use of traditional treatment scheme.

  7. MRI-based multiscale models for the hemodynamic and structural evaluation of surgically reconstructed aortic arches

    DEFF Research Database (Denmark)

    Pittaccio, S; Migliavacca, F; Balossino, R

    2007-01-01

    interposition (GGI) and Gore-tex patch graft aortoplasty (GPGA) are compared in this study with a control model, employing a computational fluid-structure-interaction scheme. This study analyzes the impact of introducing synthetic materials on aortic hemodynamics and wall mechanics. Three-dimensional (3D......-like repairs increased blood velocity, whereas GPGA limited it. Vortex presence was greater and longer lasting in GGI. The highest power losses corresponded to GPGA. GGI had an intermediate effect, while E/E dissipated only slightly more than the control case. Wall stresses peak in a longitudinal strip...

  8. Additional Value of Transluminal Attenuation Gradient in CT Angiography to Predict Hemodynamic Significance of Coronary Artery Stenosis

    Science.gov (United States)

    Stuijfzand, Wynand J.; Danad, Ibrahim; Raijmakers, Pieter G.; Marcu, C. Bogdan; Heymans, Martijn W.; van Kuijk, Cornelis C.; van Rossum, Albert C.; Nieman, Koen; Min, James K.; Leipsic, Jonathon; van Royen, Niels; Knaapen, Paul

    2015-01-01

    OBJECTIVES The current study evaluates the incremental value of transluminal attenuation gradient (TAG), TAG with corrected contrast opacification (CCO), and TAG with exclusion of calcified coronary segments (ExC) over coronary computed tomography angiogram (CTA) alone using fractional flow reserve (FFR) as the gold standard. BACKGROUND TAG is defined as the contrast opacification gradient along the length of a coronary artery on a coronary CTA. Preliminary data suggest that TAG provides additional functional information. Interpretation of TAG is hampered by multiple heartbeat acquisition algorithms and coronary calcifications. Two correction models have been proposed based on either dephasing of contrast delivery by relating coronary density to corresponding descending aortic opacification (TAG-CCO) or excluding calcified coronary segments (TAG-ExC). METHODS Eighty-five patients with intermediate probability of coronary artery disease were prospectively included. All patients underwent step-and-shoot 256-slice coronary CTA. TAG, TAG-CCO, and TAG-ExC analyses were performed followed by invasive coronary angiography in conjunction with FFR measurements of all major coronary branches. RESULTS Thirty-four patients (40%) were diagnosed with hemodynamically-significant coronary artery disease (i.e., FFR ≤0.80). On a per-vessel basis (n = 253), 59 lesions (23%) were graded as hemodynamically significant, and the diagnostic accuracy of coronary CTA (diameter stenosis ≥50%) was 95%, 75%, 98%, and 54% for sensitivity, specificity, negative predictive value, and positive predictive value, respectively. TAG and TAG-ExC did not discriminate between vessels with or without hemodynamically significant lesions (−13.5 ± 17.1 HU [Hounsfield units] × 10 mm−1 vs. −11.6 ± 13.3 HU × 10 mm−1, p = 0.36; and 13.1 ± 15.9 HU × 10 mm−1 vs. −11.4 ± 11.7 HU × 10 mm−1, p = 0.77, respectively). TAG-CCO was lower in vessels with a hemodynamically-significant lesion (−0

  9. Contrast-induced nephropathy in interventional cardiology

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    Sudarsky D

    2011-07-01

    Full Text Available Doron Sudarsky, Eugenia NikolskyCardiology Department, Rambam Health Care Campus and Technion-Israel Institute of Technology, Haifa, IsraelAbstract: Development of contrast-induced nephropathy (CIN, ie, a rise in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the first 2–3 days after contrast administration, is strongly associated with both increased inhospital and late morbidity and mortality after invasive cardiac procedures. The prevention of CIN is critical if long-term outcomes are to be optimized after percutaneous coronary intervention. The prevalence of CIN in patients receiving contrast varies markedly (from <1% to 50%, depending on the presence of well characterized risk factors, the most important of which are baseline chronic renal insufficiency and diabetes mellitus. Other risk factors include advanced age, anemia, left ventricular dysfunction, dehydration, hypotension, renal transplant, low serum albumin, concomitant use of nephrotoxins, and the volume of contrast agent. The pathophysiology of CIN is likely to be multifactorial, including direct cytotoxicity, apoptosis, disturbances in intrarenal hemodynamics, and immune mechanisms. Few strategies have been shown to be effective to prevent CIN beyond hydration, the goal of which is to establish brisk diuresis prior to contrast administration, and to avoid hypotension. New strategies of controlled hydration and diuresis are promising. Studies are mixed on whether prophylactic oral N-acetylcysteine reduces the incidence of CIN, although its use is generally recommended, given its low cost and favorable side effect profile. Agents which have been shown to be ineffective or harmful, or for which data supporting routine use do not exist, include fenoldopam, theophylline, dopamine, calcium channel blockers, prostaglandin E1, atrial natriuretic peptide, statins, and angiotensin-converting enzyme inhibitors.Keywords: contrast-induced nephropathy, contrast media

  10. 不同类型子宫瘢痕妊娠动脉栓塞治疗前后病灶血流变化的研究%Study on hemodynamic changes of pregnancy tissue material before and after the artery embolization in different types of cesarean scar pregnancy

    Institute of Scientific and Technical Information of China (English)

    陈莉婷; 陈向东; 汪洪

    2016-01-01

    目的:通过对各种类型的子宫瘢痕妊娠(CSP)进行子宫动脉栓塞治疗,观察动脉栓塞治疗前后病灶局部的血流动力学变化,探讨动脉栓塞治疗对各种类型子宫瘢痕妊娠的疗效。方法选择佛山市妇幼保健院2007年1月~2015年12月收治的CSP患者共124例,应用B超影像学将CSP患者分为Ⅰ型、Ⅱ型及ⅡⅢ型,分别对应为A(38例)、B(46例)、C(40例)三组,全部行双侧子宫动脉栓塞治疗,72h后行清宫术,比较三组患者介入治疗的有效率、介入治疗后血液β-HCG下降情况及妊娠组织物局部的血流阻力指数变化。结果(1)三组患者有效率分别为95.00%、95.83%及100.00%,无统计学差异(P>0.05)。总有效率达96.88%。(2)三组患者血流阻力指数下降50%所需时间分别为A组(42.65±13.17)h,B组(56.31±16.25)h, C组(29.72±9.26)h,三组患者时间差别之间的比较差异均有统计学意义(P<0.05)。(3)三组患者血液β-HCG下降50%所需时间分别为A组(5.37±1.52)d,B组(5.84±1.21)d,C组(3.52±1.02)d,其中A、B两组差异无统计学意义(P>0.05),A、C与B、C两组之间差异有统计学意义(P<0.05)。结论动脉栓塞治疗对各种类型的CSP均有较好的疗效,但对于治疗的个体化实施方案的确定,仍需要进一步研究。%Objective By performing uterine artery embolization in treating cesarean scar pregnancy, to observe hemodynamic changes of pregnancy tissue material before and after uterine artery embolization in different types of uterine scar pregnancy, and to explore the effects of uterine artery embolization in treating cesarean scar pregnancy. Methods 124 patients with cesarean scar pregnancy were divided into typeⅠ, typeⅡ and type Ⅲ by B ultrasound imaging, which were selected from January 2007 to December 2015 in the Maternal and Child Health Hospital of Foshan City in this

  11. Biomarkers of Hemodynamic Stress and Aortic Stiffness after STEMI: A Cross-Sectional Analysis

    Directory of Open Access Journals (Sweden)

    Sebastian Johannes Reinstadler

    2015-01-01

    Full Text Available Aim. Increased aortic stiffness might adversely affect cardiac structure, function, and perfusion. Release of biomarkers of hemodynamic stress is thought to be enhanced by these alterations. We aimed to evaluate the association between biomarkers of hemodynamic stress and aortic stiffness assessed at a chronic stage after ST-segment elevation myocardial infarction (STEMI. Methods. Fifty-four patients four months after STEMI were enrolled in this cross-sectional, single-center study. N-terminal pro–B-type natriuretic peptide (NT-proBNP, mid-regional pro–A-type natriuretic peptide (MR-proANP, and mid-regional proadrenomedullin (MR-proADM levels were measured by established assays. Aortic stiffness was assessed by the measurement of pulse wave velocity using phase-contrast cardiovascular magnetic resonance. Results. NT-proBNP, MR-proANP, and MR-proADM concentrations were all correlated with aortic stiffness in univariate analysis (r=0.378, r=0.425, and r=0.532; all P<0.005, resp.. In multiple linear regression analysis, NT-proBNP (β=0.316, P=0.005 and MR-proADM (β=0.284, P<0.020 levels were associated with increased aortic stiffness independently of age, blood pressure, and renal function. NT-proBNP was the strongest predictor for high aortic stiffness (area under the curve: 0.82, 95% CI 0.67–0.96. Conclusion. At a chronic stage after STEMI, concentrations of biomarkers for hemodynamic stress, especially NT-proBNP, are positively correlated with aortic stiffness. These biomarkers might also be useful as predictors of high aortic stiffness after STEMI.

  12. Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

    Science.gov (United States)

    Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Cowan, Brett

    2016-02-01

    Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

  13. Hemodynamic coherence and the rationale for monitoring the microcirculation.

    Science.gov (United States)

    Ince, Can

    2015-01-01

    This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation following conditions of shock and cardiovascular compromise, and why it is important to monitor the microcirculation in such conditions. The article emphasizes that if resuscitation procedures are based on the correction of systemic variables, there must be coherence between the macrocirculation and microcirculation if systemic hemodynamic-driven resuscitation procedures are to be effective in correcting organ perfusion and oxygenation. However, in conditions of inflammation and infection, which often accompany states of shock, vascular regulation and compensatory mechanisms needed to sustain hemodynamic coherence are lost, and the regional circulation and microcirculation remain in shock. We identify four types of microcirculatory alterations underlying the loss of hemodynamic coherence: type 1, heterogeneous microcirculatory flow; type 2, reduced capillary density induced by hemodilution and anemia; type 3, microcirculatory flow reduction caused by vasoconstriction or tamponade; and type 4, tissue edema. These microcirculatory alterations can be observed at the bedside using direct visualization of the sublingual microcirculation with hand-held vital microscopes. Each of these alterations results in oxygen delivery limitation to the tissue cells despite the presence of normalized systemic hemodynamic variables. Based on these concepts, we propose how to optimize the volume of fluid to maximize the oxygen-carrying capacity of the microcirculation to transport oxygen to the tissues.

  14. Practical Steps for Applying a New Dynamic Model to Near-Infrared Spectroscopy Measurements of Hemodynamic Oscillations and Transient Changes

    Science.gov (United States)

    Kainerstorfer, Jana M.; Sassaroli, Angelo; Hallacoglu, Bertan; Pierro, Michele L.; Fantini, Sergio

    2015-01-01

    Rationale and Objectives Perturbations in cerebral blood volume (CBV), blood flow (CBF), and metabolic rate of oxygen (CMRO2) lead to associated changes in tissue concentrations of oxy- and deoxy-hemoglobin (ΔO and ΔD), which can be measured by near-infrared spectroscopy (NIRS). A novel hemodynamic model has been introduced to relate physiological perturbations and measured quantities. We seek to use this model to determine functional traces of cbv(t) and cbf(t) − cmro2(t) from time-varying NIRS data, and cerebrovascular physiological parameters from oscillatory NIRS data (lowercase letters denote the relative changes in CBV, CBF, and CMRO2 with respect to baseline). Such a practical implementation of a quantitative hemodynamic model is an important step toward the clinical translation of NIRS. Materials and Methods In the time domain, we have simulated O(t) and D(t) traces induced by cerebral activation. In the frequency domain, we have performed a new analysis of frequency-resolved measurements of cerebral hemodynamic oscillations during a paced breathing paradigm. Results We have demonstrated that cbv(t) and cbf(t) − cmro2(t) can be reliably obtained from O(t) and D(t) using the model, and that the functional NIRS signals are delayed with respect to cbf(t) − cmro2(t) as a result of the blood transit time in the microvasculature. In the frequency domain, we have identified physiological parameters (e.g., blood transit time, cutoff frequency of autoregulation) that can be measured by frequency-resolved measurements of hemodynamic oscillations. Conclusions The ability to perform noninvasive measurements of cerebrovascular parameters has far-reaching clinical implications. Functional brain studies rely on measurements of CBV, CBF, and CMRO2, whereas the diagnosis and assessment of neurovascular disorders, traumatic brain injury, and stroke would benefit from measurements of local cerebral hemodynamics and autoregulation. PMID:24439332

  15. Comparing the effect of Peer education and orientation tour on the hemodynamic indices of Patients Candidate for Coronary Angiography

    Directory of Open Access Journals (Sweden)

    Farsi Zahra

    2016-02-01

    Full Text Available Background and Objective: Patients undergoing coronary angiography suffer from anxiety and worry for various reasons. This leads to changes in hemodynamic indices. The current study aimed to compare the effect of peer education and orientation tour on the hemodynamic indices in patients candidate for coronary angiography. Materials and Methods: In this quasi-experimental study, population was the patients candidate for coronary angiography who referred to selected hospital of AJA University of Medical Sciences in 2014-2015. 177 patients were selected through convenience sampling and were randomly assigned into three groups of peer education, orientation tours and control.(each group of 59 persons. The patients were trained in angiography unit by peer in the peer education group, and by researcher in the orientation tour group. Hemodynamic indices of patients were measured and recorded 2 hours after admission and two hours before angiography. Data were analyzed through using SPSS21, Chi-square test, one-way ANOVA and Paired t-test.. . Results: After intervention in peer education method, the systolic blood pressure (p=0.01, diastolic blood pressure (p=0.05, respiratory rate (p=0.03 and heart rate (p=0.001 was significantly reduced. All of these indices was significantly reduced in orientation tour group (p=0.001, while in the control group, all of the hemodynamic indices increased (p=0.001. After the intervention, there was a significant difference between intervention and control groups (p=0.001. Conclusion: The peer education and orientation tour can lead to reduction of hemodynamic indices of patients candidate for coronary angiography; therefore, the application of these training approaches is recommended.

  16. Non-invasive quantification of hemodynamics in human choriocapillaries

    Science.gov (United States)

    Yu, Huidan (Whitney); Chen, Rou; An, Senyou; McDonough, James; Gelfand, Bradley; Yao, Jun

    2016-11-01

    The development of retinal disease is inextricably linked to defects in the choroidal blood supply. However, to date a description of the hemodynamics in the human choroidal circulation is lacking. Through high resolution choroidal vascular network mapped from immunofluorescent labeling and confocal microscopy of human cadaver donor eyes. We noninvasively quantify hemodynamics including velocity, pressure, and wall-shear stress (WSS) in choriocapillaries through mesoscale modeling and GPU-accelerated fast computation. This is the first-ever map of hemodynamic parameters (WSS, pressure, and velocity) in anatomically accurate human choroidal vasculature in health and disease. The pore scale simulation results are used to evaluate porous media models with the same porosity and boundary conditions. School of Medicine, Indiana University.

  17. Upper extremity hemodynamics and sensation with backpack loads.

    Science.gov (United States)

    Kim, Sae Hoon; Neuschwander, Timothy B; Macias, Brandon R; Bachman, Larry; Hargens, Alan R

    2014-05-01

    Heavy backpacks are often used in extreme environments, for example by military during combat, therefore completion of tasks quickly and efficiently is of operational relevance. The purpose of this study was to quantify hemodynamic parameters (brachial artery Doppler and microvascular flow by photoplethysmography; tissue oxygenation by near-infrared spectroscopy; arterial oxygen saturation by pulse oximeter) and sensation in upper extremities and hands (Semmes-Weinstein monofilament test and 2-point discrimination test) while wearing a loaded backpack (12 kg) in healthy adults for 10 min. All values were compared to baseline before wearing a backpack. Moderate weight loaded backpack loads significantly decreased upper extremity sensation as well as all macrovascular and microvascular hemodynamic values. Decreased macrovascular and microvascular hemodynamics may produce neurological dysfunction and consequently, probably affect fine motor control of the hands.

  18. Features of Extracranial Hemodynamics in Children with Bronchial Asthma

    Directory of Open Access Journals (Sweden)

    S.M. Nedelska

    2014-11-01

    Full Text Available The paper analyzes the performance of extracranial hemodynamics — volumetric and linear blood flow velocity, the state of peripheral vascular resistance and vascular reactivity at ultrasound Doppler examination of the internal carotid and vertebral arteries of 66 children with bronchial asthma and and 22 healthy children. Development of regional hypoperfusion in vertebrobasilar zone, disorders of the carotid system are proven, but these changes have not led to a decrease in the volumetric blood flow velocity in both internal carotid arteries and the total volume of cerebral blood flow, indicating the compensation of hemodynamic disturbances due to the influence of constant rates in volumetric blood flow in the carotid system. Changes in parameters of extracranial hemodynamics in children with bronchial asthma should be considered as predictor of cerebrovascular complications in this group of patients.

  19. Acute dark chocolate ingestion is beneficial for hemodynamics via enhancement of erythrocyte deformability in healthy humans.

    Science.gov (United States)

    Radosinska, Jana; Horvathova, Martina; Frimmel, Karel; Muchova, Jana; Vidosovicova, Maria; Vazan, Rastislav; Bernatova, Iveta

    2017-03-01

    Erythrocyte deformability is an important property of erythrocytes that considerably affects blood flow and hemodynamics. The high content of polyphenols present in dark chocolate has been reported to play a protective role in functionality of erythrocytes. We hypothesized that chocolate might influence erythrocytes not only after repeated chronic intake, but also immediately after its ingestion. Thus, we determined the acute effect of dark chocolate and milk (with lower content of biologically active substances) chocolate intake on erythrocyte deformability. We also focused on selected factors that may affect erythrocyte deformability, specifically nitric oxide production in erythrocytes and total antioxidant capacity of plasma. We determined posttreatment changes in the mentioned parameters 2hours after consumption of chocolate compared with their levels before consumption of chocolate. In contrast to milk chocolate intake, the dark chocolate led to a significantly higher increase in erythrocyte deformability. Nitric oxide production in erythrocytes was not changed after dark chocolate intake, but significantly decreased after milk chocolate. The plasma total antioxidant capacity remained unaffected after ingestion of both chocolates. We conclude that our hypothesis was confirmed. Single ingestion of dark chocolate improved erythrocyte deformability despite unchanged nitric oxide production and antioxidant capacity of plasma. Increased deformability of erythrocytes may considerably improve rheological properties of blood and thus hemodynamics in humans, resulting in better tissue oxygenation. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Clinical implications of portal hemodynamics after small-diameter portacaval H graft

    Energy Technology Data Exchange (ETDEWEB)

    Sarfeh, I.J.; Rypins, E.B.; Fardi, M.; Conroy, R.M.; Mason, G.R.; Lyons, K.P.

    1984-08-01

    To assess the role of portal hemodynamics in the development of postshunt encephalopathy, we studied 19 patients after small-diameter portacaval H grafting (SD-PCHG). We used contrast studies as well as technetium-labeled macroaggregated albumin injected into the portal vein to assess direction of portal flow. We then quantitated the mesenteric fraction of flow perfusing the liver by injecting macroaggregated albumin into a peripheral mesenteric vein tributary. We found that none of seven patients with prograde flow by both scintigraphy and angiography developed postoperative encephalopathy, but the incidence was 58% in the remaining patients (p . 0.02). The fraction of mesenteric flow perfusing the liver after SD-PCHG was 12% +/- 4%, but this did not significantly correlate with encephalopathy rates. We conclude that after SD-PCHG, prograde portal flow minimizes encephalopathy rates. Although encephalopathy occurs in patients with predominantly reversed flow, a subgroup of patients with reversed flow remain without symptoms. The absolute fraction of mesenteric flow perfusing the liver has less influence on encephalopathy rates than has direction of portal flow. This study identifies a complex relationship between portal hemodynamics and encephalopathy.

  1. The influence of the aortic valve angle on the hemodynamic features of the thoracic aorta

    Science.gov (United States)

    Ha, Hojin; Kim, Guk Bae; Kweon, Jihoon; Lee, Sang Joon; Kim, Young-Hak; Kim, Namkug; Yang, Dong Hyun

    2016-08-01

    Since the first observation of a helical flow pattern in aortic blood flow, the existence of helical blood flow has been found to be associated with various pathological conditions such as bicuspid aortic valve, aortic stenosis, and aortic dilatation. However, an understanding of the development of helical blood flow and its clinical implications are still lacking. In our present study, we hypothesized that the direction and angle of aortic inflow can influence helical flow patterns and related hemodynamic features in the thoracic aorta. Therefore, we investigated the hemodynamic features in the thoracic aorta and various aortic inflow angles using patient-specific vascular phantoms that were generated using a 3D printer and time-resolved, 3D, phase-contrast magnetic resonance imaging (PC-MRI). The results show that the rotational direction and strength of helical blood flow in the thoracic aorta largely vary according to the inflow direction of the aorta, and a higher helical velocity results in higher wall shear stress distributions. In addition, right-handed rotational flow conditions with higher rotational velocities imply a larger total kinetic energy than left-handed rotational flow conditions with lower rotational velocities.

  2. Hemodynamic effects of propranolol with spironolactone in patients with variceal bleeds: A randomized controlled trial

    Institute of Scientific and Technical Information of China (English)

    Binay K De; Deep Dutta; Rimi Som; Pranab K Biswas; Subrata K Pal; Anirban Biswas

    2008-01-01

    AIM: To study the hemodynamic effects of spironolactone with propranolol vs propranolol alone in the secondary prophylaxis of variceal bleeding.METHODS: Thirty-five cirrhotics with variceal bleeding randomly received propranolol (n = 17: Group A) or spironolactone plus propranolol (n = 18: Group B). Hemodynamic assessment was performed at baseline and on the eighth day.RESULTS: Spironolactone with propranolol caused a greater reduction in the hepatic venous pressure gradient than propranolol alone (26.94% vs 10.2%; P < 0.01). Fourteen out of eighteen patients on the combination treatment had a reduction in hepatic venous pressure gradient to < 12 mmHg or a 20% reduction from baseline in contrast to only six out of seventeen (6/17) on propranolol alone (P < 0.05).CONCLUSION: Spironolactone with propranolol results in a better response with a greater reduction in hepatic venous pressure gradient in the secondary prophylaxis of variceal bleeding. A greater number of patients may be protected by this combination therapy than by propranolol alone. Hence, this combination may be recommended for secondary prophylaxis in patients with variceal bleeding.

  3. Insulin sensitivity and hemodynamic responses to insulin in Wistar-Kyoto and spontaneously hypertensive rats.

    Science.gov (United States)

    Pître, M; Nadeau, A; Bachelard, H

    1996-10-01

    The insulin-mediated vasodilator effect has been proposed as an important physiological determinant of insulin action on glucose disposal in normotensive humans. The present study was designed to further examine the acute regional hemodynamic effects of insulin in different vascular beds and to explore the relationships between insulin vascular effects and insulin sensitivity during euglycemic hyperinsulinemic clamps in conscious normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The rats were instrumented with intravascular catheters and pulsed Doppler flow probes to measure blood pressure, heart rate, and regional blood flows. In WKY rats, the euglycemic infusion of insulin (4 and 16 mU.kg-1.min-1) causes vasodilations in renal and hindquarter vascular beds but no changes in mean blood pressure, heart rate, or superior mesenteric vascular conductance. In contrast, in SHR, the same doses of insulin produce vasoconstrictions in superior mesenteric and hindquarter vascular beds and, at high doses, increase blood pressure. Moreover, at the lower dose of insulin tested, we found a reduction in the insulin sensitivity index in the SHR compared with the WKY rats. The present findings provide further evidence for an association between insulin sensitivity and insulin-mediated hemodynamic responses.

  4. Bayesian model comparison in nonlinear BOLD fMRI hemodynamics

    DEFF Research Database (Denmark)

    Jacobsen, Danjal Jakup; Hansen, Lars Kai; Madsen, Kristoffer Hougaard

    2008-01-01

    Nonlinear hemodynamic models express the BOLD (blood oxygenation level dependent) signal as a nonlinear, parametric functional of the temporal sequence of local neural activity. Several models have been proposed for both the neural activity and the hemodynamics. We compare two such combined models......: the original balloon model with a square-pulse neural model (Friston, Mechelli, Turner, & Price, 2000) and an extended balloon model with a more sophisticated neural model (Buxton, Uludag, Dubowitz, & Liu, 2004). We learn the parameters of both models using a Bayesian approach, where the distribution...

  5. Hemodynamic factors in the genesis of diabetic microangiopathy

    DEFF Research Database (Denmark)

    Parving, H H; Viberti, G C; Keen, H

    1983-01-01

    There are many candidate mechanisms to explain the phenomenon of delayed microvascular disease in the diabetic. All may play some part in determining the genesis, the evolution or the ultimate degree and form of the angiopathy. General metabolic and humoral factors may provide the pathogenetic...... conditions for the evolution of microvascular disease. The hemodynamic changes and the vascular responses to them that we have described are, we suggest, very likely to be an important component of this sort. Unlike the later structural changes, these hemodynamic phenomena are to be found very early...

  6. Ultrasonic Imaging of Hemodynamic Force in Carotid Blood Flow

    Science.gov (United States)

    Nitta, N.; Homma, K.

    Hemodynamic forces including blood pressure and shear stress affect vulnerable plaque rupture in arteriosclerosis and biochemical activation of endothelium such as NO production. In this study, a method for estimating and imaging shear stress and pressure gradient distributions in blood vessel as the hemodynamic force based on viscosity estimation is presented. Feasibility of this method was investigated by applying to human carotid blood flow. Estimated results of shear stress and pressure gradient distributions coincide with the ideal distributions obtained by numerical simulation and flow-phantom experiment.

  7. The hemodynamic management of elderly patients with sepsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sepsis is among the most common reason for admission to intensive care units throughout the world. In the US and most Western nations sepsis is largely a disease of the elderly. Management of elderly patients with severe sepsis is challenging. Early recognition of this syndrome, together with the early administration of appropriate antibiotics and cautious fluid resuscitation is the cornerstone of therapy. Echocardiography together with non-invasive or invasive hemodynamic monitoring is recommended in patients who have responded poorly to fluids or have significant underlying cardiac disease. This paper reviews the hemodynamic changes that characterize sepsis, particularly as they apply to elderly patients and provides recommendations for the management of these patients.

  8. Hemodynamic effects and safety of pulmonary angiography in Chinese patients with pulmonary hypertension

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-liang; SUN Xing-guo; WANG Yong; LIU Zhi-hong; XIONG Chang-ming; NI Xin-hai; HE Jian-guo; LUO Qin; ZHAO Zhi-hui; ZHAO Qing

    2011-01-01

    Background Pulmonary angiography is widely performed in pulmonary hypertension patients,but its immediate effects on right heart hemodynamics and safety are not well known.The objective of this study was to investigate the right heart hemodynamic effects and safety of pulmonary angiography in Chinese patients with pulmonary hypertension.Methods Between January 2008 and June 2009,pulmonary hypertension patients undergoing pulmonary angiography were consecutively enrolled.Pulmonary angiography was performed during breath-holding after deep breathing.The baselineclinical data,hemodynamic measurements before and after pulmonary angiography and complications occurring within 48hours after angiography were recorded.Results Ninety-five patients were included.All received non-ionic contrast medium with a volume of (75.7±29.8) ml.Angiography reduced heart rate in patients with baseline mean pulmonary arterial pressure ≥ 60 mmHg (change of heart rate:(-3.1±7.0) beats/min,P=0.005),increased mean right atrial pressure,diastolic and end-diastolic right ventricular pressure in patients with baseline mean pulmonary arterial pressure <60 mmHg (all P <0.05).Patients with decreased mean pulmonary arterial pressure (change of mean pulmonary arterial pressure ≤ -10 mmHg) had the highest total pulmonary resistance (P=0.009 vs.no change in mean pulmonary arterial pressure (change of mean pulmonary arterial pressure,-10 mmHg to 10 mmHg); P=0.03 vs.increased mean pulmonary arterial pressure (change of mean pulmonary arterial pressure ≥ 10 mmHg)) and the lowest cardiac output (P=0.018 vs.no change in mean pulmonary arterial pressure; P=0.013 vs.increased mean pulmonary arterial pressure).There were 7 complications (7%),with 6 related to catheter and only 1 directly related to angiography.All complications were mild and no death occurred.Conclusion Pulmonary angiography has minimal effect on right heart hemodynamics and is safe in pulmonary hypertension patients.

  9. Contrast-induced nephropathy

    Directory of Open Access Journals (Sweden)

    Ricardo A. García Hernández

    2016-06-01

    Full Text Available Contrast-induced nephropathy is an important complication associated with the use of contrast media. Favoring factors for the development of contrast-induced nephronpathy have been widely described, being diabetes mellitus and previous renal disease the greatest risk. The pathophysiology is a complex process where the medullary hypoxia represents the trigger element. Previous hydration and the use of low osmolality contrast are the most recommended measures to prevent its development.

  10. The Influence of Age on Hemodynamic Parameters During Rest and Exercise in Healthy Individuals

    DEFF Research Database (Denmark)

    Wolsk, Emil; Bakkestrøm, Rine; Thomsen, Jacob H

    2016-01-01

    The authors sought to obtain hemodynamic estimates across a wide age span and in both sexes for future reference and compare these estimates with current guideline diagnostic hemodynamic thresholds...

  11. The Influence of Age on Hemodynamic Parameters During Rest and Exercise in Healthy Individuals

    DEFF Research Database (Denmark)

    Wolsk, Emil; Bakkestrøm, Rine; Thomsen, Jacob H

    2017-01-01

    . Participants had hemodynamic parameters measured using right heart catheterization during rest, passive leg raise, and incremental exercise. RESULTS: During rest, all hemodynamic parameters were similar between age groups, apart from blood pressure. During leg raise and incremental exercise...

  12. Methylene Blue Is Effective to Reverse Refractory Hemodynamic Instability due to Dimethoate Poisoning

    Directory of Open Access Journals (Sweden)

    Nick Youssefi

    2015-09-01

    Conclusion:MB treatment was effective to reverse hypotension and restore hemodynamic instability caused by dimethoate poisoning. This index case may pave way to further investigation of MB therapy for OP-induced hemodynamic instabilities.

  13. Magnetic resonance imaging based noninvasive measurements of brain hemodynamics in neonates : A review

    NARCIS (Netherlands)

    De Vis, Jill B; Alderliesten, Thomas; Hendrikse, Jeroen; Petersen, Esben T; Benders, Manon Jnl

    2016-01-01

    Perinatal disturbances of brain hemodynamics can have a detrimental effect on the brain's parenchyma with consequently adverse neurodevelopmental outcome. Noninvasive, reliable tools to evaluate the neonate's brain hemodynamics are scarce. Advances in magnetic resonance imaging have provided new met

  14. Acute coronary hemodynamic effects of equihypotensive doses of nisoldipine and diltiazem

    NARCIS (Netherlands)

    H. Suryapranata (Harry); P.W.J.C. Serruys (Patrick); A.L. Soward; J. Planellas; G. Vanhaleweyk; P.G. Hugenholtz (Paul)

    1985-01-01

    textabstractThe hemodynamic effects of nisoldipine and diltiazem were investigated in two groups of patients undergoing investigation for suspected coronary artery disease. Emphasis was placed on the coronary hemodynamic changes. Approximately equihypotensive doses of these two calcium channel block

  15. Magnetic resonance imaging based noninvasive measurements of brain hemodynamics in neonates

    DEFF Research Database (Denmark)

    De Vis, Jill B; Alderliesten, Thomas; Hendrikse, Jeroen

    2016-01-01

    Perinatal disturbances of brain hemodynamics can have a detrimental effect on the brain's parenchyma with consequently adverse neurodevelopmental outcome. Noninvasive, reliable tools to evaluate the neonate's brain hemodynamics are scarce. Advances in magnetic resonance imaging have provided new...... methods to noninvasively assess brain hemodynamics. More recently these methods have made their transition to the neonatal population. The aim of this review is twofold. Firstly, to describe these newly available noninvasive methods to investigate brain hemodynamics in neonates. Secondly, to discuss...

  16. Relationship between angiotensin-(1-7) and angiotensin Ⅱ correlates with hemodynamic changes in human liver cirrhosis

    Institute of Scientific and Technical Information of China (English)

    Walkia Wingester Vilas-Boas; Antio Ribeiro-Oliveira Jr; Regina Maria Pereira; Renata da Cunha Ribeiro; Jerusa Almeida; Ana Paula Nadu; Ana Cristina Simoes e Silva; Robson Augusto Souza dos Santos

    2009-01-01

    AIM:To measure circulating angiotensins at different stages of human cirrhosis and to further evaluate a possible relationship between renin angiotensin system (RAS) components and hemodynamic changes. METHODS:Patients were allocated into 4 groups:mild-to-moderate liver disease (MLD), advanced liverdisease (ALD), patients undergoing liver transplantation,and healthy controls. Blood was collected to determine plasma renin activity (PRA), angiotensin (Ang) Ⅱ , Ang Ⅱ , and Ang-(1-7) levels using radioimmunoassays.During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components. RESULTS:PRA and angiotensins were elevated in ALD when compared to MLD and controls ( P < 0.05).In contrast, Ang Ⅱ was significantly reduced in MLD. Ang-(1-7)/Ang Ⅱ ratios were increased in MLD when compared to controls and ALD. During transplantation,Ang Ⅱ levels were lower and Ang-(1-7)/Ang Ⅱ ratios were higher in the splanchnic circulation than in the 0.02), whereas the peripheral circulating Ang Ⅱ /Ang Ⅱ ratio was elevated in comparison to splanchnic levels Ang Ⅱ ratios positively correlated with cardiac output ( r = 0.66) and negatively correlated with systemic vascular resistance ( r = -0.70).CONCLUSION:Our findings suggest that the relationship between Ang-(1-7) and Ang Ⅱ may play a role in the hemodynamic changes of human cirrhosis.

  17. Patient-specific in vitro models for hemodynamic analysis of congenital heart disease - Additive manufacturing approach.

    Science.gov (United States)

    Medero, Rafael; García-Rodríguez, Sylvana; François, Christopher J; Roldán-Alzate, Alejandro

    2017-03-21

    Non-invasive hemodynamic assessment of total cavopulmonary connection (TCPC) is challenging due to the complex anatomy. Additive manufacturing (AM) is a suitable alternative for creating patient-specific in vitro models for flow measurements using four-dimensional (4D) Flow MRI. These in vitro systems have the potential to serve as validation for computational fluid dynamics (CFD), simulating different physiological conditions. This study investigated three different AM technologies, stereolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM), to determine differences in hemodynamics when measuring flow using 4D Flow MRI. The models were created using patient-specific MRI data from an extracardiac TCPC. These models were connected to a perfusion pump circulating water at three different flow rates. Data was processed for visualization and quantification of velocity, flow distribution, vorticity and kinetic energy. These results were compared between each model. In addition, the flow distribution obtained in vitro was compared to in vivo. The results showed significant difference in velocities measured at the outlets of the models that required internal support material when printing. Furthermore, an ultrasound flow sensor was used to validate flow measurements at the inlets and outlets of the in vitro models. These results were highly correlated to those measured with 4D Flow MRI. This study showed that commercially available AM technologies can be used to create patient-specific vascular models for in vitro hemodynamic studies at reasonable costs. However, technologies that do not require internal supports during manufacturing allow smoother internal surfaces, which makes them better suited for flow analyses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Effect of Benson Relaxation Techniques on Hemodynamic Variables of Patient Undergoing Coronary Angiography

    Directory of Open Access Journals (Sweden)

    M khani

    2005-01-01

    Full Text Available Introduction: Invasive diagnostic procedures such as coronary angiography, in most cases, are accompanied by stress and anxiety for patients,which may effect on hemodynamic signs. Materials and Methods:This research, as a quasi experimental study, has the objective to determine the influence of applying methods of relaxation on hemodynamic signs in hospitalized 40 patients, experienciny coronary angiography (CA,, has been studied, in regard to existing conditions and methods of sampling and random allocation to two groups of control and relaxation at 2003 . Data collection tool included demographic and disease related information sheet, as well as record sheets for hemodynamic parameters at intervals of 8-12 and ½ hrs before, during and after the angiography. For relaxation group, the researcher would speak individually about the influence of relaxation, the day before angiography; Then with the aid of client himself/herself, performed relaxation instances in a single bout, and eventually asked client to perform relaxation technique 2-3 times before going for angiography. In control group was attended in the usual manner preangiographically. Homodynamic parameters were measured in both groups 8-12 and ½ hrs, before during and after CA. Afterward, resulted data were analyzed statistically by T-Test Chi-squre. Results: With T-Test, respiratory rates½ hrs, beforeAngiography, diastolic blood pressure and Respiratory Rate after Angiography showed statisticaly significant difference between two groups (P0.05.but most of parameters showed clinically significant difference between two groups. Conclusion: Therfore it is offered that relaxation method is applied after invasive procedures.

  19. Decreased Vertebral Artery Hemodynamics in Patients with Loss of Cervical Lordosis.

    Science.gov (United States)

    Bulut, Mehmet Deniz; Alpayci, Mahmut; Şenköy, Emre; Bora, Aydin; Yazmalar, Levent; Yavuz, Alpaslan; Gülşen, İsmail

    2016-02-15

    BACKGROUND Because loss of cervical lordosis leads to disrupted biomechanics, the natural lordotic curvature is considered to be an ideal posture for the cervical spine. The vertebral arteries proceed in the transverse foramen of each cervical vertebra. Considering that the vertebral arteries travel in close anatomical relationship to the cervical spine, we speculated that the loss of cervical lordosis may affect vertebral artery hemodynamics. The aim of this study was to compare the vertebral artery values between subjects with and without loss of cervical lordosis. MATERIAL AND METHODS Thirty patients with loss of cervical lordosis and 30 controls matched for age, sex, and body mass index were included in the study. Sixty vertebral arteries in patients with loss of cervical lordosis and 60 in controls without loss of cervical lordosis were evaluated by Doppler ultrasonography. Vertebral artery hemodynamics, including lumen diameter, flow volume, peak systolic velocity, end-diastolic velocity, and resistive index, were measured, and determined values were statistically compared between the patient and the control groups. RESULTS The means of diameter (p=0.003), flow volume (p=0.002), and peak systolic velocity (p=0.014) in patients were significantly lower as compared to controls. However, there was no significant difference between the 2 groups in terms of the end-diastolic velocity (p=0.276) and resistive index (p=0.536) parameters. CONCLUSIONS The present study revealed a significant association between loss of cervical lordosis and decreased vertebral artery hemodynamics, including diameter, flow volume, and peak systolic velocity. Further studies are required to confirm these findings and to investigate their possible clinical implications.

  20. 4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents – A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Bunck, Alexander C., E-mail: alexander.bunck@uk-koeln.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Department of Radiology, University Hospital Cologne, Kerpener Strasse 62, 50937 Cologne (Germany); Jüttner, Alena, E-mail: alenajuettner@gmx.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Kröger, Jan Robert, E-mail: jr.kroeger@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Burg, Matthias C., E-mail: m_burg03@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Kugel, Harald, E-mail: kugel@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Niederstadt, Thomas, E-mail: tnieders@uni-muenster.de [Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Tiemann, Klaus, E-mail: Klaus.Tiemann@ukmuenster.de [Department of Cardiology and Angiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster (Germany); Schnackenburg, Bernhard, E-mail: bernhard.schnackenburg@philips.com [Philips Medical Systems DMC GmbH, Röntgenstraße 24, 22335 Hamburg (Germany); Crelier, Gerard R., E-mail: crelier@biomed.ee.ethz.ch [Institute for Biomedical Engineering, ETH and University of Zurich, ETZ F 95, Gloriastrasse 35, 8092 Zurich (Switzerland); and others

    2012-09-15

    Purpose: 4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. Materials and methods: 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. Results: In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10). Conclusions: 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type.

  1. Pharmacological management of hemodynamic complications following spinal cord injury.

    Science.gov (United States)

    McMahon, Deanna; Tutt, Matthew; Cook, Aaron M

    2009-05-01

    Damage from spinal cord injury (SCI) may be complicated by concomitant hemodynamic alterations within hours to months of the initial insult. Neurogenic shock, symptomatic bradycardia, autonomic dysreflexia, and orthostatic hypotension are specific conditions occurring commonly with SCI. Early recognition and appropriate management of each disorder may minimize secondary injury to the cord, avert systemic complications, and help alleviate patient discomfort.

  2. Less invasive hemodynamic monitoring in critically ill patients

    NARCIS (Netherlands)

    Teboul, Jean-Louis; Saugel, Bernd; Cecconi, Maurizio; De Backer, Daniel; Hofer, Christoph K.; Monnet, Xavier; Perel, Azriel; Pinsky, Michael R.; Reuter, Daniel A.; Rhodes, Andrew; Squara, Pierre; Vincent, Jean-Louis; Scheeren, Thomas W.

    2016-01-01

    Over the last decade, the way to monitor hemodynamics at the bedside has evolved considerably in the intensive care unit as well as in the operating room. The most important evolution has been the declining use of the pulmonary artery catheter along with the growing use of echocardiography and of co

  3. Clinical monitoring of systemic hemodynamics in critically ill newborns.

    NARCIS (Netherlands)

    Boode, W.P. de

    2010-01-01

    Circulatory failure is a major cause of mortality and morbidity in critically ill newborn infants. Since objective measurement of systemic blood flow remains very challenging, neonatal hemodynamics is usually assessed by the interpretation of various clinical and biochemical parameters. An overview

  4. Acute hemodynamic response to vasodilators in primary pulmonary hypertension.

    Directory of Open Access Journals (Sweden)

    Kulkarni H

    1996-01-01

    Full Text Available Acute hemodynamic effects of high flow oxygen (O2 inhalation, sublingual isosorbide dinitrate (ISDN, intravenous aminophylline (AMN and sublingual nifedipine (NIF were studied in 32 patients with primary pulmonary hypertension (PPH. In 30 out of 32 patients the basal ratio of pulmonary to systemic vascular resistance (Rp/Rs was > 0.5 (mean = 0.77 +/- 0.20. Oxygen caused significant decrease in the mean resistance ratio to 0.68 +/- 0.20 (p = 0.005. ISDN, AMN and NIF caused increase in the resistance ratio to 0.79 +/- 0.26; 0.78 +/- 0.26; and 0.80 +/- 0.23 respectively. O2, ISDN, AMN and NIF caused a fall of Rp/Rs in 21 (65.6%, 10 (31.2%, 10(31.2% and 9(28.1% patients respectively. Thus, of the four drugs tested high flow O2 inhalation resulted in fall of Rp/Rs in two thirds of patients whereas ISDN, AMN and NIF caused a mean rise in Rp/Rs. One third of patients did respond acutely to the latter three drugs. Acute hemodynamic studies are useful before prescribing vasodilators in patients with PPH since more of the commonly used drugs like ISDN, AMN, NIF could have detrimental hemodynamic responses in some patients. However, great caution should be exercised before performing hemodynamic study as the procedure has definite mortality and morbidity.

  5. Relationship Between Serum Uric Acid Levels and Intrarenal Hemodynamic Parameters

    Directory of Open Access Journals (Sweden)

    Hideki Uedono

    2015-06-01

    Full Text Available Background/Aims: Hyperuricemia has been reported to affect renal hemodynamics in rat models. We evaluate the relationship between serum uric acid and intrarenal hemodynamic parameters in humans, utilizing the plasma clearance of para-aminohippurate (CPAH and inulin (Cin. Methods: Renal and glomerular hemodynamics were assessed by simultaneous measurement of CPAH and Cin in 58 subjects. Of these, 19 subjects were planned to provide a kidney for transplantation; 26 had diabetes without proteinuria; and 13 had mild proteinuria. Renal and glomerular hemodynamics were calculated using Gomez`s formulae. Results: Cin was more than 60 ml/min/1.73m2 in all subjects. Serum uric acid levels correlated significantly with vascular resistance at the afferent arteriole (Ra (r = 0.354, p = 0.006 but not with that of the efferent arteriole (Re. Serum uric acid levels (β = 0.581, p = a after adjustment for several confounders (R2 = 0.518, p = Conclusions: These findings suggest, for the first time in humans, that higher serum uric acid levels are associated significantly with Ra in subjects with Cin > 60 ml/min/1.73m2. The increase in Ra in subjects with higher uric acid levels may be related to dysfunction of glomerular perfusion.

  6. Transmediastinal and Transcardiac Gunshot Wound with Hemodynamic Stability

    Directory of Open Access Journals (Sweden)

    Leire Zarain Obrador

    2014-01-01

    Full Text Available Cardiac injuries caused by knives and firearms are slightly increasing in our environment. We report the case of a 43-year-old male patient with a transmediastinal gunshot wound (TGSW and a through-and-through cardiac wound who was hemodynamically stable upon his admission. He had an entrance wound below the left clavicle, with no exit wound, and decreased breath sounds in the right hemithorax. Chest X-ray showed the bullet in the right hemithorax and large right hemothorax. The ultrasound revealed pericardial effusion, and a chest tube produced 1500 cc. of blood, but he remained hemodynamically stable. Considering these findings, a median sternotomy was carried out, the through-and-through cardiac wounds were suture-repaired, lung laceration was sutured, and a pacemaker was placed in the right ventricle. The patient had uneventful recovery and was discharged home on the twelfth postoperative day. The management and prognosis of these patients are determined by the hemodynamic situation upon arrival to the Emergency Department (ED, as well as a prompt surgical repair if needed. Patients with a TGSW have been divided into three groups according to the SBP: group I, with SBP >100 mmHg; group II, with SBP 60–100 mmHg; and group III, with SBP <60 mmHg. The diagnostic workup and management should be tailored accordingly, and several series have confirmed high chances of success with conservative management when these patients are hemodynamically stable.

  7. Risk factors for hemodynamic instability during surgery for pheochromocytoma

    NARCIS (Netherlands)

    H. Bruynzeel; R.A. Feelders (Richard); T.H.N. Groenland (Theo); A.H. van den Meiracker (Anton); C.H.J. van Eijck (Casper); J.F. Lange (Johan); W.W. de Herder (Wouter); G. Kazemier (Geert)

    2010-01-01

    textabstractBackground: Surgery on pheochromocytoma carries a risk for hemodynamic (HD) instability. The aim of this study was to identify preoperative risk factors for intraoperative HD instability. In addition, efficacy of pretreatment with the α-adrenergic receptor (α) antagonists phenoxybenzamin

  8. Hemodynamic Changes during Epidural Anesthesia with Various Local Anesthetics

    Directory of Open Access Journals (Sweden)

    Ye. M. Shifman

    2008-01-01

    Full Text Available Central hemodynamic stability during gynecological laparoscopic operations remains an important problem of anes-thesiological monitoring. Subjects and methods. Fifty-eight patients who had undergone various gynecological laparoscopic operations were examined. According to the mode of anesthesia, the patients were divided into 2 groups: 1 29 patients who received epidural anesthesia with ropivacaine; 2 29 who had epidural anesthesia using lidocaine. The indices of cardiac performance (stroke volume, stroke index, and cardiac output, blood (diastolic, systolic, and mean pressure, vascular parameters (linear blood flow velocity, total peripheral vascular resistance were determined by volumetric compression oscillometry. Results. The study indicated that all the modes of anesthesia demonstrated the satisfactory condition of the cardiovascular system, but the highest stability of hemodynamic parameters was recorded in the epidural ropivacaine group. In this group, there were steady-state reductions in diastolic, systolic, mean blood pressures, and total vascular peripheral resistance and increases in stroke index, stroke volume, and linear blood flow velocity. Conclusion. Epidural anesthesia using ropivacaine during gynecological surgical endoscopic interventions is the method of analgesia causing minimal hemodynamic disorders. Key words: hemodynamics, epidural anesthesia, laparoscopic gynecological operations.

  9. New approach to intracardiac hemodynamic measurements in small animals

    DEFF Research Database (Denmark)

    Eskesen, Kristian; Olsen, Niels T; Dimaano, Veronica L;

    2012-01-01

    Invasive measurements of intracardiac hemodynamics in animal models have allowed important advances in the understanding of cardiac disease. Currently they are performed either through a carotid arteriotomy or via a thoracotomy and apical insertion. Both of these techniques have disadvantages and...

  10. Initial approach to hypertension in the hemodynamics unit: review article

    Directory of Open Access Journals (Sweden)

    Gustavo Teixeira Fulton Schimit

    2013-06-01

    Full Text Available Correct identification and early management of hypertensive disorders should be a part of the therapeutic repertoire of every professional working in hemodynamics units. Based on recent publications, this study aims to propose a practical approach to the identification and early management of these disorders in this type of service.

  11. Hemodynamics and vasopressor support in therapeutic hypothermia after cardiac arrest

    DEFF Research Database (Denmark)

    Bro-Jeppesen, John; Kjaergaard, Jesper; Søholm, Helle;

    2014-01-01

    AIM: Inducing therapeutic hypothermia (TH) in Out-of-Hospital Cardiac Arrest (OHCA) can be challenging due to its impact on central hemodynamics and vasopressors are frequently used to maintain adequate organ perfusion. The aim of this study was to assess the association between level of vasopres...

  12. Hemodynamic and ventilatory response to different levels of hypoxia and hypercapnia in carotid body-denervated rats

    Directory of Open Access Journals (Sweden)

    João Paulo J. Sabino

    2013-01-01

    Full Text Available OBJECTIVE: Chemoreceptors play an important role in the autonomic modulation of circulatory and ventilatory responses to changes in arterial O2 and/or CO2. However, studies evaluating hemodynamic responses to hypoxia and hypercapnia in rats have shown inconsistent results. Our aim was to evaluate hemodynamic and respiratory responses to different levels of hypoxia and hypercapnia in conscious intact or carotid body-denervated rats. METHODS: Male Wistar rats were submitted to bilateral ligature of carotid body arteries (or sham-operation and received catheters into the left femoral artery and vein. After two days, each animal was placed into a plethysmographic chamber and, after baseline measurements of respiratory parameters and arterial pressure, each animal was subjected to three levels of hypoxia (15, 10 and 6% O2 and hypercapnia (10% CO2. RESULTS: The results indicated that 15% O2 decreased the mean arterial pressure and increased the heart rate (HR in both intact (n = 8 and carotid body-denervated (n = 7 rats. In contrast, 10% O2did not change the mean arterial pressure but still increased the HR in intact rats, and it decreased the mean arterial pressure and increased the heart rate in carotid body-denervated rats. Furthermore, 6% O2 increased the mean arterial pressure and decreased the HR in intact rats, but it decreased the mean arterial pressure and did not change the HR in carotid body-denervated rats. The 3 levels of hypoxia increased pulmonary ventilation in both groups, with attenuated responses in carotid body-denervated rats. Hypercapnia with 10% CO2 increased the mean arterial pressure and decreased HR similarly in both groups. Hypercapnia also increased pulmonary ventilation in both groups to the same extent. CONCLUSION: This study demonstrates that the hemodynamic and ventilatory responses varied according to the level of hypoxia. Nevertheless, the hemodynamic and ventilatory responses to hypercapnia did not depend on the

  13. Phase contrast image synthesis

    DEFF Research Database (Denmark)

    Glückstad, J.

    1996-01-01

    A new method is presented for synthesizing arbitrary intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range [0; 2 pi] phase modulation. By controlling the average value of the input phase...... function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis....

  14. Contrast induced nephropathy

    DEFF Research Database (Denmark)

    Stacul, Fulvio; van der Molen, Aart J; Reimer, Peter

    2011-01-01

    measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml....../min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR ≥ 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally....

  15. Contrast induced nephropathy

    DEFF Research Database (Denmark)

    Stacul, Fulvio; van der Molen, Aart J; Reimer, Peter

    2011-01-01

    measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium. • eGFR of 45 ml....../min/1.73 m (2) is CIN risk threshold for intravenous contrast medium. • Hydration with either saline or sodium bicarbonate reduces CIN incidence. • Patients with eGFR = 60 ml/min/1.73 m (2) receiving contrast medium can continue metformin normally....

  16. Contrast-enhanced endoscopic ultrasonography: advance and current status

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Sung Il [Dept. of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Lee, Dong Ki [Dept. of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2014-10-15

    Endoscopic ultrasonography (EUS) technology has undergone a great deal of progress along with the color and power Doppler imaging, three-dimensional imaging, electronic scanning, tissue harmonic imaging, and elastography, and one of the most important developments is the ability to acquire contrast-enhanced images. The blood flow in small vessels and the parenchymal microvasculature of the target lesion can be observed non-invasively by contrast-enhanced EUS (CE-EUS). Through a hemodynamic analysis, CE-EUS permits the diagnosis of various gastrointestinal diseases and differential diagnoses between benign and malignant tumors. Recently, mechanical innovations and the development of contrast agents have increased the use of CE-EUS in the diagnostic field, as well as for the assessment of the efficacy of therapeutic agents. The advances in and the current status of CE-EUS are discussed in this review.

  17. Contrast-enhanced endoscopic ultrasonography: advance and current status

    Directory of Open Access Journals (Sweden)

    Sung Ill Jang

    2014-07-01

    Full Text Available Endoscopic ultrasonography (EUS technology has undergone a great deal of progress along with the color and power Doppler imaging, three-dimensional imaging, electronic scanning, tissue harmonic imaging, and elastography, and one of the most important developments is the ability to acquire contrast-enhanced images. The blood flow in small vessels and the parenchymal microvasculature of the target lesion can be observed non-invasively by contrast-enhanced EUS (CE-EUS. Through a hemodynamic analysis, CE-EUS permits the diagnosis of various gastrointestinal diseases and differential diagnoses between benign and malignant tumors. Recently, mechanical innovations and the development of contrast agents have increased the use of CE-EUS in the diagnostic field, as well as for the assessment of the efficacy of therapeutic agents. The advances in and the current status of CE-EUS are discussed in this review.

  18. Microvascular contrast enhancement in optical coherence tomography using microbubbles

    Science.gov (United States)

    Assadi, Homa; Demidov, Valentin; Karshafian, Raffi; Douplik, Alexandre; Vitkin, I. Alex

    2016-07-01

    Gas microbubbles (MBs) are investigated as intravascular optical coherence tomography (OCT) contrast agents. Agar + intralipid scattering tissue phantoms with two embedded microtubes were fabricated to model vascular blood flow. One was filled with human blood, and the other with a mixture of human blood + MB. Swept-source structural and speckle variance (sv) OCT images, as well as speckle decorrelation times, were evaluated under both no-flow and varying flow conditions. Faster decorrelation times and higher structural and svOCT image contrasts were detected in the presence of MB in all experiments. The effects were largest in the svOCT imaging mode, and uniformly diminished with increasing flow velocity. These findings suggest the feasibility of utilizing MB for tissue hemodynamic investigations and for microvasculature contrast enhancement in OCT angiography.

  19. The impact of reliable pre-bolus T1 measurements or a fixed T1 value in the assessment of glioma patients with Dynamic Contrast Enhancing MRI

    DEFF Research Database (Denmark)

    Tietze, Anna; Mouridsen, Kim; Mikkelsen, Irene Klærke

    2015-01-01

    Purpose: Accurate quantification of hemodynamic parameters using Dynamic Contrast Enhanced MRI (DCE) requires a measurement of tissue T1 prior to contrast injection (T1). We evaluate (i) T1 estimation using the variable flip angle (VFA) and the saturation recovery (SR) techniques and (ii) investi...

  20. Quality control of PSE and the study of portal hemodynamics changes after PSE

    Institute of Scientific and Technical Information of China (English)

    Jun Cui; Ming Jun Han; Ke Rer; Ke Xu

    2000-01-01

    AIM To explore a method to control splenic embolic volume precisely for partial splenic embolization(PSE) to improve the validity and safety of PSE, and study the portal hemodynamic changes after PSE.METHODS Gelfoam particles of identical standard (2×2×1.6mm) were used as embolic material tomeasure the splenic radiographic parameters SAI (spleen activity index) was measured scanning withradioisotope technetium-99mTc sulfur colloid and splenic embolic volume was calculated with the followingformula: splenic embolic volume = [SAI(pre-PSE)-SAI(post- PSE )]/SAI(pre-PSE)×100%. The regressionequation of gelfoam particles in splenic embolic volume and splenic radiographic parameters was calculatedusing SAS (statistical analysis system) software (version 6.02). Portal hemodynamic changes were examinedby color Doppler ultrasound.RESULTS The amount of gelfoam particles was correlated with splenic embolic volume and top-bottomlength of spleen, regression equation was achieved: Y = 5.77X1 + 15.19X3-164.75, (multi-regression wasused, significant level P = 0.15). Y: number of gelfoam particles used, Xl: splenic embolic volume (%),X3: top-bottom length of spleen (cm). The diameter and blood flow volume of spleen and portal vein and thepeak velocity of spleen vein all decreased after PSE. The decreased parameters were positively correlatedwith splenic embolic volume.CONCLUSION By calculating gelfoam particles for PSE, splenic embolic volume could be controlled withinthe effective and safe limit. PSE could decrease the high dynamic circulating state of portal systemeffectively.

  1. Hemodynamic response to endotracheal intubation using C-Trach assembly and direct laryngoscopy

    Directory of Open Access Journals (Sweden)

    Jayita Sarkar

    2015-01-01

    Full Text Available Purpose: Our objective was to study the pressor response to endotracheal intubation through laryngeal mask airway C-Trach and compare it to the hemodynamic response to intubation with direct laryngoscopy (DL. Materials and Methods: After obtained approval from institutional ethical committee, 100 patients of American Society of Anesthesiologists physical Status I, aged 14-65 years, posted for elective surgery were enrolled in the trial. They were randomly divided into two groups of each 50 patients. Anesthesia technique was standardized and patients of Group I were intubated using DL, while patients of Group II were intubated with the help of C-Trach assembly. Hemodynamic parameters, systemic blood pressure (systolic and diastolic and heart rate were recorded before and after induction of anesthesia and every minute up to 5 min after intubation. Results: Patients of Group II recorded a minimal rise in peak systolic blood pressure (SBP (1.8% and diastolic blood pressure (10.6%. In comparison patients of Group I recorded a significant sustained rise in peak SBP (20.3% and diastolic blood pressure (21.4%. However heart rate changes recorded in the two groups were of equal measure (peak rise of 22.9% in Group I vs. 22.4% in Group II. Conclusion: We conclude that intubation through C-Trach generates a lower pressor response to intubation in comparison to intubation using DL.

  2. Computational Simulations of Inferior Vena Cava (IVC) Filter Placement and Hemodynamics in Patient-Specific Geometries

    Science.gov (United States)

    Aycock, Kenneth; Sastry, Shankar; Kim, Jibum; Shontz, Suzanne; Campbell, Robert; Manning, Keefe; Lynch, Frank; Craven, Brent

    2013-11-01

    A computational methodology for simulating inferior vena cava (IVC) filter placement and IVC hemodynamics was developed and tested on two patient-specific IVC geometries: a left-sided IVC, and an IVC with a retroaortic left renal vein. Virtual IVC filter placement was performed with finite element analysis (FEA) using non-linear material models and contact modeling, yielding maximum vein displacements of approximately 10% of the IVC diameters. Blood flow was then simulated using computational fluid dynamics (CFD) with four cases for each patient IVC: 1) an IVC only, 2) an IVC with a placed filter, 3) an IVC with a placed filter and a model embolus, all at resting flow conditions, and 4) an IVC with a placed filter and a model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet (all cases) and a larger stagnation region (cases 3-4) in the left-sided IVC. These results support further investigation of the effects of IVC filter placement on a patient-specific basis.

  3. Fluid-Structure Interaction Modeling of Intracranial Aneurysm Hemodynamics: Effects of Different Assumptions

    Science.gov (United States)

    Rajabzadeh Oghaz, Hamidreza; Damiano, Robert; Meng, Hui

    2015-11-01

    Intracranial aneurysms (IAs) are pathological outpouchings of cerebral vessels, the progression of which are mediated by complex interactions between the blood flow and vasculature. Image-based computational fluid dynamics (CFD) has been used for decades to investigate IA hemodynamics. However, the commonly adopted simplifying assumptions in CFD (e.g. rigid wall) compromise the simulation accuracy and mask the complex physics involved in IA progression and eventual rupture. Several groups have considered the wall compliance by using fluid-structure interaction (FSI) modeling. However, FSI simulation is highly sensitive to numerical assumptions (e.g. linear-elastic wall material, Newtonian fluid, initial vessel configuration, and constant pressure outlet), the effects of which are poorly understood. In this study, a comprehensive investigation of the sensitivity of FSI simulations in patient-specific IAs is investigated using a multi-stage approach with a varying level of complexity. We start with simulations incorporating several common simplifications: rigid wall, Newtonian fluid, and constant pressure at the outlets, and then we stepwise remove these simplifications until the most comprehensive FSI simulations. Hemodynamic parameters such as wall shear stress and oscillatory shear index are assessed and compared at each stage to better understand the sensitivity of in FSI simulations for IA to model assumptions. Supported by the National Institutes of Health (1R01 NS 091075-01).

  4. Use of Diazepam to Correct Hemodynamic Changes in Explosive Mine Injury: Experimental Study

    Directory of Open Access Journals (Sweden)

    V. N. Yelsky

    2007-01-01

    Full Text Available Objective. To study the hemodynamic effect of benzodiazepine tranquilizers in explosive mine injury in an experiment.Materials and methods. The study was performed on non-inbred male rats; hemodynamic parameters were examined at the systemic, organ, and microcirculatory levels.Results. Circulatory adaptive changes occurring at the beginning of a premorbid load further become pathogenic, which in combination with a progressive change in blood-brain barrier resistance results in the severer course of premorbid load-complicated explosive mine injury than that of isolated one. Correction of occurring disorders, by stimulating the stress-limiting GABAergic system with diazepam, is most effective within the first 25 minutes after isolated explosive mine injury and within the first 15 minutes after complicated one. Conclusion. Under the conditions of deep collieries where medical aid was generally late, emergency medical activation of urgent adaptation mechanisms by the techniques specially developed by the authors for these conditions is the most effective way of preventing the complications of explosive mine injury. 

  5. HEMODYNAMIC INSIGNIFICANT CAROTID ARTERIES STENOSIS AND RISK OF EMBOLIC STROKE IN PATIENTS WITH ISCHEMIC HEART DISEASE

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    V. V. Semenova

    2009-01-01

    Full Text Available Aim. To assess a risk of vascular embolism in patients with ischemic heart disease (IHD and hemodynamic insignificant asymptomatic carotid stenosis.Material and methods. 100 patients with IHD were examined. Ultrasound scanning of the main cranial arteries and transcranial Dopplerography was performed in all patients as well as lipid spectrum, fibrinogen level and blood D-diameter concentration were evaluated.Results. 165 carotid atherosclerotic plaques (AP were detected in patients with IHD independently on angina severity. In IHD patients with nonhomogeneous hypoechogenic AP microembolic signals (MES were revealed in 44,78%, with nonhomogeneous hyperechogenic AP - in 25%, with homogeneous hypoechogenic AP - in 4,16% of patients. MES were not recorded in patients with homogeneous hyperechogenic AP. There were not relations between MES and parameters of lipid spectrum as well as fibrinogen and Ddiameter plasma levels.Conclusion. Thus, during transcranial dopplerographic monitoring MES were recorded in the third part (27,9% of IHD patients with hemodynamically insignificant carotid arteries stenosis. MES were predominantly observed in patients with nonhomogeneous AP especially with hypoechogenic components.

  6. Efficiency of Physical Therapy for Improving Hemodynamic Parameters in Young Obese Patients

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    Iuliana GHERGHEL

    2012-12-01

    Full Text Available Aim: The paper aims to demonstrate the efficiency of an individualized exercise training protocol on preventing cardiovascular complications, by improving hemodynamic parameters and body composition of young obese patiens. Material and method: The group included 35 subjects from which 21 female and 14 male with age between 18 and 25 years and the period of the study was 9 months of which 6 of training. At the beginning and at the end of training, subjects were assessed in regard to body composition and hemodynamic parameters. To design an individualized exercise training program, testing and monitoring protocol was based on using of some modern methods among which: cardiopulmonary exercise testing and bioimedance body composition analyses. Statistical analysis was performed by using paired t test. Value of the coefficient p under 0.05 was considered statistically significant. Results: Training programs performed during 6 months have brought significant improvements in the following parameters: body mass index, resting heart rate, systolic blood presure and dyastolic blood pressure, allong with maximal blood presure in effort. Conclusions: The concept of individual intervals training brought improvements of targeted parameters, causing weight loss but also improvements of cardiovascular risk.

  7. Hemodynamic and hormonal actions of adrenomedullin

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    M.G. Nicholls

    2004-08-01

    Full Text Available Adrenomedullin, a 52-amino acid residue peptide, has numerous biological actions which are of potential importance to cardiovascular homeostasis, growth and development of cardiovascular tissues and bone, prevention of infection, and regulation of body fluid and electrolyte balance. Studies in man using intravenous infusion of the peptide have demonstrated that, at plasma levels detected after myocardial infarction or in heart failure, adrenomedullin reduces arterial pressure, increases heart rate and cardiac output, and activates the sympathetic and renin-angiotensin systems but suppresses aldosterone. The thresholds for these responses differ, being lower under some experimental circumstances for arterial pressure than for the other biological effects. Adrenomedullin administration inhibits the pressor and aldosterone-stimulating action of angiotensin II in man. By contrast, the pressor effect of norepinephrine is little altered by concomitant adrenomedullin administration. Although in the absence of a safe, specific antagonist of the actions of endogenous adrenomedullin it is difficult to be certain about the physiological and pathophysiological importance of this peptide in man, current evidence suggests that it serves to protect against cardiovascular overload and injury. Hope has been expressed that adrenomedullin or an agonist specific for adrenomedullin receptors might find a place in the treatment of cardiovascular disorders.

  8. Postprandial hemodynamics in the conscious rat

    Energy Technology Data Exchange (ETDEWEB)

    Anzueto Hernandez, L.; Kvietys, P.R.; Granger, D.N.

    1986-07-01

    The postprandial intestinal hyperemia was studied in conscious and anesthetized rats using the radioactive microsphere technique. Carbohydrate, protein, lipid, and mixed meals, and the vehicle (Tyrode's solution), were placed in the stomach via a gastrostomy tube. In conscious rats, blood flow increased by 40-80% in the duodenum and jejunum 1 h after either a carbohydrate, lipid, protein, or mixed meal. Tyrode's solution produced a comparable hyperemia. Blood flow in the distal bowel segments (ileum, cecum, and colon) was significantly increased only by Tyrode's solution and the carbohydrate meal. The proximal intestinal hyperemia produced by the mixed meal in conscious animals was significantly attenuated by vagotomy yet unaltered by atropine pretreatment. In contrast to the results obtained from conscious rats, the mixed meal did not significantly alter intestinal blood flow in anesthetized animals. The results of this study indicate that the postprandial intestinal hyperemia is much greater in conscious than anesthetized animals. This difference may result from the higher resting blood flows in the latter group. The hyperemic response in conscious animals may be mediated by the vagus nerve.

  9. Hemodynamic modeling of the intrarenal circulation.

    Science.gov (United States)

    M'rabet Bensalah, K; Uehlinger, D; Kalicki, R; Czerwinska, J

    2013-12-01

    Three dimensional, time dependent numerical simulations of healthy and pathological conditions in a model kidney were performed. Blood flow in a kidney is not commonly investigated by computational approach, in contrast for example, to the flow in a heart. The flow in a kidney is characterized by relatively small Reynolds number (100 laminar regime). The presented results give insight into the structure of such flow, which is hard to measure in vivo. The simulations have suggested that venous thrombosis is more likely than arterial thrombosis-higher shear rate observed. The obtained maximum velocity, as a result of the simulations, agrees with the observed in vivo measurements. The time dependent simulations show separation regimes present in the vicinity of the maximum pressure value. The pathological constriction introduced to the arterial geometry leads to the changes in separation structures. The constriction of a single vessel affects flow in the whole kidney. Pathology results in different flow rate values in healthy and affected branches, as well as, different pulsate cycle characteristic for the whole system.

  10. Inverse correlation between testosterone and ventricle ejection fraction, hemodynamics and exercise capacity in heart failure patients with erectile dysfunction

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    Edimar A. Bocchi

    2008-06-01

    Full Text Available BACKGROUND: Neurohormonal activation and abnormalities in growth hormone and testosterone concentrations have been reported in heart failure (HF. Erectile dysfunction(ED is common in these patients and contributes to a low quality of life. No data are known regarding the correlation between testosterone and hemodynamics, exercise capacity and cardiac function in HF patients with ED, a marker of endothelial dysfunction. The aim of this study was to correlate testosterone levels with cardiac function, hemodynamic and exercise capacity in HF patients with ED. MATERIALS AND METHODS: Fifteen HF patients underwent a six-minute treadmill cardiopulmonary walking test (6'CWT and, ten minutes later, a maximum cardiopulmonary exercise test. Also, testosterone and other hormones were determined at rest. RESULTS: Among hemodynamic variables only diastolic blood pressure on 6'CWT was correlated with testosterone levels(r =- 0.66, p = 0.007. The variables on exercise tests, VE/VCO2 slope and oxygen consumption did not show any correlation, except the distance at 6'CWT (r = 0.50, p = 0,047. Right and left ventricle ejection fraction showed inverse correlation with testosterone (r =- 0.55, p = 0.03 and r =- 0.69, p = 0.004 respectively. CONCLUSION: Testosterone levels correlated directly with distance at six-minute cardiopulmonary walk test and inversely with diastolic blood pressure, right and left ventricle ejection fraction in heart failure patients with erectile dysfunction. Further elucidation of mechanisms as regards testosterone action in these patients is warranted.

  11. Comparison of Dexmedetomidine and Propofol for hemodynamic changes and depth of an a esthesia (using BIS monitor during laparoscopic surgery

    Directory of Open Access Journals (Sweden)

    Dr Shah Vandana

    2015-01-01

    Full Text Available Abstract: Introduction: Laparoscopy is one of the commonest surgical procedures includes creation of pneumoperitoneum with carbon dioxide which in turns causes hemodynamic instability. To manage this instability, several drugs are tried and used. Dexmedetomidine, a selective α -2 agonist, is used for sedation and hemodynamic stability. Aims: This study aims to compare the effect of i.v. Dexmedetomidine and propofol infusion on heart rate and blood pressure attenuation and depth of anesthesia using BIS monitor during laparoscopic surgery. Material and Method: 50 patients of ASA grade I/II divided in to two groups. Group D (n=25 received Dexmedetomidine 1 mcg/kg/10min loading dose followed by 0.2 –0.7 mcg/kg/min infusion. Group P (n=25 received 25 -75mcg/kg/min propofol infusion. Observation: Up to 30 minutes of surgery heart rate stability was better in group D, after 30 minutes it was comparable in both the groups. Mean arterial pressure was better maintained up to 75 minutes in group D, after 75 minutes it was comparable in both the groups. Conclusion : Dexmedetomidine infusion attenuates hemodynamic response to laryngoscopy and pneumoperitoneum with adequate depth of anesthesia better than propofol.

  12. Evaluation of cerebral hemodynamics with perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Yuzo; Furuichi, Masahiro; Nokura, Hiroaki [Inuyama Central Hospital, Aichi (Japan); Sakai, Noboru [Gifu Univ. (Japan). School of Medicine

    2002-07-01

    We report on the evaluation of cerebral ischemic lesions with perfusion CT. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of 52 patients mostly with ischemic cerebrovascular disease were analysed using the box-modulation transfer function method with 30 ml of contrast medium intravenously injected at 5 ml/sec. CBF, CBV and MTT of the middle cerebral artery (MCA) territory were 43.5{+-}4.6 ml/100 g/min, 1.9{+-}0.2 ml/100 g and 2.9{+-}0.6 seconds at the unaffected side, and 37.7{+-}7.3 ml/100 g /min, 2.1{+-}0.3 ml/100 g, 3.7{+-}0.9 seconds at the lesion side with stenosis or occlusion in the main MCA trunks or internal carotid artery, respectively. A statistically significant difference was shown in CBF and MTT values. Furthermore, there was a close correlation in CBF values of MCA territories between Xe-CT and perfusion CT (r=0.645, n=76, p<0.0001). MTT showed a positive correlation with CBV in those subjects when MTT was below 4.1 seconds (r=0.526, p<0.0001, n=83). MTT also showed a negative correlation with CBF in those patients when MTT indicated more than 4.1 seconds (r=0.818, p<0.001, n=21). These results suggest that the progression of cerebral ischemia may be classified in 4 stages using perfusion CT. The stages are as follows: stage 0; normal CBF without prolonged MTT and increased CBV, stage 1; relatively increased CBV, stage 2; significantly prolonged MTT, and stage 3; significantly deceased CBF with prolonged MTT. (author)

  13. Splanchnic and systemic hemodynamic derangement in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Henriksen, Jens Henrik

    2001-01-01

    significance to the low systemic vascular resistance and abnormal volume distribution of blood, which are important elements in the development of the concomitant cardiac dysfunction, recently termed 'cirrhotic cardiomyopathy'. Systolic and diastolic functions are impaired with direct relation to the degree...... in vasodilation and increased arterial compliance. Reflex-induced, enhanced sympathetic nervous system activity, activation of the renin-angiotensin aldosterone system, and elevated circulation vasopressin and endothelin-1 are implicated in hemodynamic counter-regulation in cirrhosis. Recent research has focused......Patients with cirrhosis and portal hypertension exhibit characteristic hemodynamic changes with hyperkinetic systemic circulation, abnormal distribution of blood volume and neurohumoral dysregulation. Their plasma and noncentral blood volumes are increased. Splanchnic vasodilation is of pathogenic...

  14. Optimal control of CPR procedure using hemodynamic circulation model

    Science.gov (United States)

    Lenhart, Suzanne M.; Protopopescu, Vladimir A.; Jung, Eunok

    2007-12-25

    A method for determining a chest pressure profile for cardiopulmonary resuscitation (CPR) includes the steps of representing a hemodynamic circulation model based on a plurality of difference equations for a patient, applying an optimal control (OC) algorithm to the circulation model, and determining a chest pressure profile. The chest pressure profile defines a timing pattern of externally applied pressure to a chest of the patient to maximize blood flow through the patient. A CPR device includes a chest compressor, a controller communicably connected to the chest compressor, and a computer communicably connected to the controller. The computer determines the chest pressure profile by applying an OC algorithm to a hemodynamic circulation model based on the plurality of difference equations.

  15. Clinical relevance of fetal hemodynamic monitoring: Perinatal implications.

    Science.gov (United States)

    Pruetz, Jay D; Votava-Smith, Jodie; Miller, David A

    2015-08-01

    Comprehensive assessment of fetal wellbeing involves monitoring of fetal growth, placental function, central venous pressure, and cardiac function. Ultrasound evaluation of the fetus using 2D, color Doppler, and pulse-wave Doppler techniques form the foundation of antenatal diagnosis of structural anomalies, rhythm abnormalities and altered fetal circulation. Accurate and timely prenatal identification of the fetus at risk is critical for appropriate parental counseling, antenatal diagnostic testing, consideration for fetal intervention, perinatal planning, and coordination of postnatal care delivery. Fetal hemodynamic monitoring and serial assessment are vital to ensuring fetal wellbeing, particularly in the setting of complex congenital anomalies. A complete hemodynamic evaluation of the fetus gives important information on the likelihood of a smooth postnatal transition and contributes to ensuring the best possible outcome for the neonate.

  16. [The hemodynamic characterization of the diabetic patient with arterial calcifications].

    Science.gov (United States)

    Vega Gómez, M E; Ley Pozo, J; Aldama Figueroa, A; Lima Santana, B; Montalvo Diago, J; Bustillo, C; Fernández Boloña, A; Gutiérrez Jiménez, O; Ramirez Muñoz, O; Martínez Hernández, R

    1993-01-01

    This study was designed to describe the presence of calcifications according to the clinical features of the diabetic patient and the hemodynamics of the calcified arteries. With this purpose, 197 lower limbs from diabetic patients (type I and II) and carbon-hydrate intolerant patients, were studied. In all of the patients, the pressure ratio leg/arm was measured. On the same way, the arterial flow velocity was recorded using the Doppler ultrasonography on the pedia and postero-tibial arteries. The arterial calcifications, evident on the radiography of the foot, were more frequent between the type I patients and the neuro-infections diabetic foot. According to the hemodynamics point of view, we found a trend of association of more pathologic arterial flow velocity curves with the presence of calcifications (specially on the intima layer). It was also remarkable that an arterial incomprensibility was always associated with arterial calcifications.

  17. Rifaximin has no effect on hemodynamics in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Kimer, Nina; Pedersen, Julie Steen; Busk, Troels Malte

    2017-01-01

    , P = 0.14, or vasoactive hormones were found. Subgroup analyses on patients with increased lipopolysaccharide binding protein and systemic vascular resistance below the mean (1,011 dynes × s/cm(5) ) revealed no effect of rifaximin. CONCLUSION: Four weeks of treatment with rifaximin did not reduce......Decompensated cirrhosis is characterized by disturbed systemic and splanchnic hemodynamics. Bacterial translocation from the gut is considered the key driver in this process. Intestinal decontamination with rifaximin may improve hemodynamics. This double-blind, randomized, controlled trial...... years (±8.4), average Child score 8.3 (±1.3), and Model for End-Stage Liver Disease score 11.7 (±3.9). Measurements of hepatic venous pressure gradient, cardiac output, and systemic vascular resistance were made at baseline and after 4 weeks. The glomerular filtration rate and plasma renin...

  18. Effects of an interatrial shunt on rest and exercise hemodynamics

    DEFF Research Database (Denmark)

    Kaye, David; Shah, Sanjiv J; Borlaug, Barry A

    2014-01-01

    of the conditions tested. CONCLUSIONS: The interatrial shunt reduced left-sided cardiac output with a marked reduction in PCWP. This approach may reduce the propensity for heart failure exacerbations and allow patients to exercise longer, thus attaining higher heart rates and cardiac outputs with the shunt compared......BACKGROUND: A treatment based on an interatrial shunt device has been proposed for counteracting elevated pulmonary capillary wedge pressure (PCWP) in patients with heart failure and mildly reduced or preserved ejection fraction (HFpEF). We tested the theoretical hemodynamic effects...... of this approach with the use of a previously validated cardiovascular simulation. METHODS AND RESULTS: Rest and exercise hemodynamics data from 2 previous independent studies of patients with HFpEF were simulated. The theoretical effects of a shunt between the right and left atria (diameter up to 12 mm) were...

  19. Describing contrast across scales

    Science.gov (United States)

    Syed, Sohaib Ali; Iqbal, Muhammad Zafar; Riaz, Muhammad Mohsin

    2017-06-01

    Due to its sensitive nature against illumination and noise distributions, contrast is not widely used for image description. On the contrary, the human perception of contrast along different spatial frequency bandwidths provides a powerful discriminator function that can be modeled in a robust manner against local illumination. Based upon this observation, a dense local contrast descriptor is proposed and its potential in different applications of computer vision is discussed. Extensive experiments reveal that this simple yet effective description performs well in comparison with state of the art image descriptors. We also show the importance of this description in multiresolution pansharpening framework.

  20. Pharmacological Modulation of Hemodynamics in Adult Zebrafish In Vivo.

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    Daniel Brönnimann

    Full Text Available Hemodynamic parameters in zebrafish receive increasing attention because of their important role in cardiovascular processes such as atherosclerosis, hematopoiesis, sprouting and intussusceptive angiogenesis. To study underlying mechanisms, the precise modulation of parameters like blood flow velocity or shear stress is centrally important. Questions related to blood flow have been addressed in the past in either embryonic or ex vivo-zebrafish models but little information is available for adult animals. Here we describe a pharmacological approach to modulate cardiac and hemodynamic parameters in adult zebrafish in vivo.Adult zebrafish were paralyzed and orally perfused with salt water. The drugs isoprenaline and sodium nitroprusside were directly applied with the perfusate, thus closely resembling the preferred method for drug delivery in zebrafish, namely within the water. Drug effects on the heart and on blood flow in the submental vein were studied using electrocardiograms, in vivo-microscopy and mathematical flow simulations.Under control conditions, heart rate, blood flow velocity and shear stress varied less than ± 5%. Maximal chronotropic effects of isoprenaline were achieved at a concentration of 50 μmol/L, where it increased the heart rate by 22.6 ± 1.3% (n = 4; p < 0.0001. Blood flow velocity and shear stress in the submental vein were not significantly increased. Sodium nitroprusside at 1 mmol/L did not alter the heart rate but increased blood flow velocity by 110.46 ± 19.64% (p = 0.01 and shear stress by 117.96 ± 23.65% (n = 9; p = 0.03.In this study, we demonstrate that cardiac and hemodynamic parameters in adult zebrafish can be efficiently modulated by isoprenaline and sodium nitroprusside. Together with the suitability of the zebrafish for in vivo-microscopy and genetic modifications, the methodology described permits studying biological processes that are dependent on hemodynamic alterations.

  1. Splanchnic and systemic hemodynamic derangement in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Bendtsen, F; Henriksen, Jens Henrik Sahl

    2001-01-01

    Patients with cirrhosis and portal hypertension exhibit characteristic hemodynamic changes with hyperkinetic systemic circulation, abnormal distribution of blood volume and neurohumoral dysregulation. Their plasma and noncentral blood volumes are increased. Splanchnic vasodilation is of pathogenic...... of liver dysfunction. Significant pathophysiological mechanisms are reduced beta-adrenergic receptor signal transduction, defective cardiac excitation-contraction coupling and conductance abnormalities. Vasodilators such as nitric oxide and calcitonin gene-related peptide are among the candidates...

  2. Combined Visualization of Vessel Deformation and Hemodynamics in Cerebral Aneurysms.

    Science.gov (United States)

    Meuschke, Monique; Voss, Samuel; Beuing, Oliver; Preim, Bernhard; Lawonn, Kai

    2017-01-01

    We present the first visualization tool that combines patient-specific hemodynamics with information about the vessel wall deformation and wall thickness in cerebral aneurysms. Such aneurysms bear the risk of rupture, whereas their treatment also carries considerable risks for the patient. For the patient-specific rupture risk evaluation and treatment analysis, both morphological and hemodynamic data have to be investigated. Medical researchers emphasize the importance of analyzing correlations between wall properties such as the wall deformation and thickness, and hemodynamic attributes like the Wall Shear Stress and near-wall flow. Our method uses a linked 2.5D and 3D depiction of the aneurysm together with blood flow information that enables the simultaneous exploration of wall characteristics and hemodynamic attributes during the cardiac cycle. We thus offer medical researchers an effective visual exploration tool for aneurysm treatment risk assessment. The 2.5D view serves as an overview that comprises a projection of the vessel surface to a 2D map, providing an occlusion-free surface visualization combined with a glyph-based depiction of the local wall thickness. The 3D view represents the focus upon which the data exploration takes place. To support the time-dependent parameter exploration and expert collaboration, a camera path is calculated automatically, where the user can place landmarks for further exploration of the properties. We developed a GPU-based implementation of our visualizations with a flexible interactive data exploration mechanism. We designed our techniques in collaboration with domain experts, and provide details about the evaluation.

  3. Altering hemodynamics leads to congenital heart defects (Conference Presentation)

    Science.gov (United States)

    Ford, Stephanie M.; McPheeters, Matthew T.; Wang, Yves T.; Gu, Shi; Doughman, Yong Qiu; Strainic, James P.; Rollins, Andrew M.; Watanabe, Michiko; Jenkins, Michael W.

    2016-03-01

    The role of hemodynamics in early heart development is poorly understood. In order to successfully assess the impact of hemodynamics on development, we need to monitor and perturb blood flow, and quantify the resultant effects on morphology. Here, we have utilized cardiac optical pacing to create regurgitant flow in embryonic hearts and OCT to quantify regurgitation percentage and resultant morphology. Embryonic quail in a shell-less culture were optically paced at 3 Hz (well above the intrinsic rate or 1.33-1.67 Hz) on day 2 of development (3-4 weeks human) for 5 minutes. The pacing fatigued the heart and led to a prolonged period (> 1 hour) of increased regurgitant flow. Embryos were kept alive until day 3 (cardiac looping - 4-5 weeks human) or day 8 (4 chambered heart - 8 weeks human) to quantify resultant morphologic changes with OCT. All paced embryos imaged at day 3 displayed cardiac defects. The extent of regurgitant flow immediately after pacing was correlated with cardiac cushion size 24-hours post pacing (p-value congenital heart defects (CHDs) including 11/18 with valve defects, 5/18 with ventricular septal defects and 5/18 with hypoplastic right ventricles. Our data suggests that regurgitant flow leads to smaller cushions, which develop into abnormal valves and septa. Our model produces similar phenotypes as found in our fetal alcohol syndrome and velo-cardio-facial/DiGeorge syndrome models suggesting that hemodynamics plays a role in these syndromes as well. Utilizing OCT and optical pacing to understand hemodynamics in development is an important step towards determining CHD mechanisms and ultimately developing earlier treatments.

  4. The hemodynamic basis of exercise intolerance in tricuspid regurgitation

    DEFF Research Database (Denmark)

    Andersen, Mads Jønsson; Nishimura, Rick a; Borlaug, Barry A

    2014-01-01

    ≥3 TR underwent high-fidelity invasive hemodynamic exercise testing with simultaneous expired gas analysis and were compared with 13 age- and sex-matched controls. At rest, TR subjects had lower pulmonary blood flow (3.6±0.4 versus 5.1±1.9 L/min; P=0.01), increased right atrial pressure (12±5 versus...

  5. Continuous Hemodynamic Monitoring in Acute Stroke: An Exploratory Analysis

    Directory of Open Access Journals (Sweden)

    Ayan Sen

    2014-07-01

    Full Text Available Introduction: Non-invasive, continuous hemodynamic monitoring is entering the clinical arena. The primary objective of this study was to test the feasibility of such monitoring in a pilot sample of Emergency Department (ED stroke patients. Secondary objectives included analysis of hemodynamic variability and correlation of continuous blood pressure measurements with standard measurements. Methods: This study was a secondary analysis of 7 stroke patients from a prospectively collected data set of patients that received 2 hours of hemodynamic monitoring in the ED. Stroke patients were included if hemorrhagic or ischemic stroke was confirmed by neuroimaging, and symptom onset was within 24 hours. They were excluded for the presence of a stroke mimic or transient ischemic attack. Monitoring was performed using the Nexfin device (Edwards Lifesciences, Irvine CA. Results: The mean age of the cohort was 71 ± 17 years, 43% were male, and the mean National Institute of Health Stroke Scale (NIHSS was 6.9 ± 5.5. Two patients had hemorrhagic stroke. We obtained 42,456 hemodynamic data points, including beat-to-beat blood pressure measurements with variability of 18 mmHg and cardiac indices ranging from 1.8 to 3.6 l/min/m2. The correlation coefficient between continuous blood pressure measurements with the Nexfin device and standard ED readings was 0.83. Conclusion: This exploratory investigation revealed that continuous, noninvasive monitoring in the ED is feasible in acute stroke. Further research is currently underway to determine how such monitoring may impact outcomes in stroke or replace the need for invasive monitoring. [West J Emerg Med. 2014;15(4:–0.

  6. Renal Function and Hemodynamic Study in Obese Zucker Rats

    OpenAIRE

    Park, Sung Kwang; Kang, Sung Kyew

    1995-01-01

    Objectives To investigate the renal function and hemodynamic changes in obesity and hyperinsulinemia which are characteristics of type II diabetes. Methods Studies were carried out in two groups of female Zucker rats. Group 1 rats were obese Zucker rats with hereditary insulin resistance. Group 2 rats were lean Zucker rats and served as controls. In comparison with lean Zucker rats, obese Zucker rats exhibited hyperinsulinemia but normoglycemia. Micropuncture studies and morphologic studies w...

  7. [Intracardiac hemodynamic changes in the newborns with respiratory distress syndrome].

    Science.gov (United States)

    Perepelitsa, S A; Korotkaia, M V; Pavlenko, O V; Golubev, A M

    2009-01-01

    The paper provides the results of intracardiac circulation ultrasound study in 37 preterm neonatal infants, including 24 patients with severe respiratory distress syndrome (RDS), receiving the exogenous surfactant Curosurf in the complex therapy of the disease. A control comprised 12 apparently healthy preterm neonates who had no clinical signs of RDS in the early adaptive period or artificial ventilation (AV). Both groups were similar in the major anthropometric characteristics and gestational age. The objective of this investigation was to make Doppler echocardiographic study of blood flow through all cardiac valves in the newborn with RDS during AV. The investigation indicated that the neonates with severe RDS had increases in peak blood flow velocity and in peak pressure gradient through the valves of the great vessels: the aorta and pulmonary trunk, and abnormal regurgitation flow mainly through the pulmonary arterial valve, which was a sign of intensive hemodynamic adaptation in the acute phase of disease. By the third day of life, some neonatal infants without clinical signs of RDS were observed to have signs of intensive hemodynamic adaptation: increases in peak blood flow velocity and in peak pressure gradient through the valves of the pulmonary trunk. Irrespective of the specific features of the course of an early neonatal period, neonatal infants need Doppler echocardiographic monitoring for the evaluation of intracardiac hemodynamics.

  8. Hemodynamic stroke: A rare pitfall in cranio cervical junction surgery

    Directory of Open Access Journals (Sweden)

    Jan Frederick Cornelius

    2014-01-01

    Full Text Available Surgical C1C2-stabilization may be complicated by arterial-arterial embolism or arterial injury. Another potential complication is hemodynamic stroke. The latter might be induced in patients with poor posterior fossa collateralization (risk factor 1 when the vertebral artery (VA is compressed during reduction (risk factor 2. We report a clinical case where this rare situation occurred: A 72-year old patient was undergoing C1C2-stabilization for subluxation due to rheumatoid arthritis. Preoperative computed tomography angiography (CTA had shown poor collaterals in the posterior fossa. Furthermore, intraoperative Doppler ultrasound (US detected unilateral VA occlusion during reduction. It appeared to be a high-risk situation for hemodynamic stroke. Surgical inspection of the VA found osteofibrous compressing elements. Arterial decompression was performed resulting in the normal flow as detected by US. Subsequently, C1C2-stabilization could be realized. The clinical and radiological outcome was very favorable. In C1C2-stabilization precise analysis of preoperative CTA and intraoperative US are important to detect risk factors of hemodynamic stroke. Using these data may prevent this rare, but potentially life-threatening complication.

  9. Human bulbar conjunctival hemodynamics in hemoglobin SS and SC disease.

    Science.gov (United States)

    Wanek, Justin; Gaynes, Bruce; Lim, Jennifer I; Molokie, Robert; Shahidi, Mahnaz

    2013-08-01

    The known biophysical variations of hemoglobin (Hb) S and Hb C may result in hemodynamic differences between subjects with SS and SC disease. The purpose of this study was to measure and compare conjunctival hemodynamics between subjects with Hb SS and SC hemoglobinopathies. Image sequences of the conjunctival microcirculation were acquired in 9 healthy control subjects (Hb AA), 24 subjects with SC disease, and 18 subjects with SS disease, using a prototype imaging system. Diameter (D) and blood velocity (V) measurements were obtained in multiple venules of each subject. Data were categorized according to venule caliber by averaging V and D for venules with diameters less than (vessel size 1) or greater than (vessel size 2) 15 µm. V in vessel size 2 was significantly greater than V in vessel size 1 in the AA and SS groups (P ≥ 0.009), but not in the SC group (P = 0.1). V was significantly lower in the SC group as compared to the SS group (P = 0.03). In AA and SS groups, V correlated with D (P ≤ 0.005), but the correlation was not statistically significant in the SC group (P = 0.08). V was inversely correlated with hematocrit in the SS group for large vessels (P = 0.03); however, no significant correlation was found in the SC group (P ≥ 0.2). Quantitative assessment of conjunctival microvascular hemodynamics in SS and SC disease may advance understanding of sickle cell disease pathophysiology and thereby improve therapeutic interventions.

  10. Quantifying the abnormal hemodynamics of sickle cell anemia

    Science.gov (United States)

    Lei, Huan; Karniadakis, George

    2012-02-01

    Sickle red blood cells (SS-RBC) exhibit heterogeneous morphologies and abnormal hemodynamics in deoxygenated states. A multi-scale model for SS-RBC is developed based on the Dissipative Particle Dynamics (DPD) method. Different cell morphologies (sickle, granular, elongated shapes) typically observed in deoxygenated states are constructed and quantified by the Asphericity and Elliptical shape factors. The hemodynamics of SS-RBC suspensions is studied in both shear and pipe flow systems. The flow resistance obtained from both systems exhibits a larger value than the healthy blood flow due to the abnormal cell properties. Moreover, SS-RBCs exhibit abnormal adhesive interactions with both the vessel endothelium cells and the leukocytes. The effect of the abnormal adhesive interactions on the hemodynamics of sickle blood is investigated using the current model. It is found that both the SS-RBC - endothelium and the SS-RBC - leukocytes interactions, can potentially trigger the vicious ``sickling and entrapment'' cycles, resulting in vaso-occlusion phenomena widely observed in micro-circulation experiments.

  11. Invasive hemodynamic monitoring in the postoperative period of cardiac surgery

    Directory of Open Access Journals (Sweden)

    Desanka Dragosavac

    1999-08-01

    Full Text Available OBJETIVE: To assess the hemodynamic profile of cardiac surgery patients with circulatory instability in the early postoperative period (POP. METHODS: Over a two-year period, 306 patients underwent cardiac surgery. Thirty had hemodynamic instability in the early POP and were monitored with the Swan-Ganz catheter. The following parameters were evaluated: cardiac index (CI, systemic and pulmonary vascular resistance, pulmonary shunt, central venous pressure (CVP, pulmonary capillary wedge pressure (PCWP, oxygen delivery and consumption, use of vasoactive drugs and of circulatory support. RESULTS: Twenty patients had low cardiac index (CI, and 10 had normal or high CI. Systemic vascular resistance was decreased in 11 patients. There was no correlation between oxygen delivery (DO2 and consumption (VO2, p=0.42, and no correlation between CVP and PCWP, p=0.065. Pulmonary vascular resistance was decreased in 15 patients and the pulmonary shunt was increased in 19. Two patients with CI < 2L/min/m² received circulatory support. CONCLUSION: Patients in the POP of cardiac surgery frequently have a mixed shock due to the systemic inflammatory response syndrome (SIRS. Therefore, invasive hemodynamic monitoring is useful in handling blood volume, choice of vasoactive drugs, and indication for circulatory support.

  12. Comprehensive cognitive and cerebral hemodynamic evaluation after cranioplasty

    Directory of Open Access Journals (Sweden)

    Coelho F

    2014-05-01

    Full Text Available Fernanda Coelho,1 Arthur Maynart Oliveira,2 Wellingson Silva Paiva,2 Fabio Rios Freire,1 Vanessa Tome Calado,1 Robson Luis Amorim,2 Iuri Santana Neville,2 Almir Ferreira de Andrade,2 Edson Bor-Seng-Shu,3 Renato Anghinah,1 Manoel Jacobsen Teixeira21Neurorehabilitation Group, Division of Neurology, 2Division of Neurosurgery, 3Neurosonology and Cerebral Hemodynamics Group, University of São Paulo Medical School, São Paulo, BrazilAbstract: Decompressive craniectomy is an established procedure to lower intracranial pressure and can save patients' lives. However, this procedure is associated with delayed cognitive decline and cerebral hemodynamics complications. Studies show the benefits of cranioplasty beyond cosmetic aspects, including brain protection, and functional and cerebrovascular aspects, but a detailed description of the concrete changes following this procedure are lacking. In this paper, the authors report a patient with trephine syndrome who underwent cranioplasty; comprehensive cognitive and cerebral hemodynamic evaluations were performed prior to and following the cranioplasty. The discussion was based on a critical literature review.Keywords: cranioplasty, decompressive craniotomy, perfusion CT, traumatic brain injury, cognition, neuropsychological test

  13. Particle Image Velocimetry studies of bicuspid aortic valve hemodynamics

    Science.gov (United States)

    Saikrishnan, Neelakantan; Yap, Choon-Hwai; Yoganathan, Ajit P.

    2010-11-01

    Bicuspid aortic valves (BAVs) are a congenital anomaly of the aortic valve with two fused leaflets, affecting about 1-2% of the population. BAV patients have much higher incidence of valve calcification & aortic dilatation, which may be related to altered mechanical forces from BAV hemodynamics. This study aims to characterize BAV hemodynamics using Particle Image Velocimetry(PIV). BAV models are constructed from normal explanted porcine aortic valves by suturing two leaflets together. The valves are mounted in an acrylic chamber with two sinuses & tested in a pulsatile flow loop at physiological conditions. 2D PIV is performed to obtain flow fields in three planes downstream of the valve. The stenosed BAV causes an eccentric jet, resulting in a very strong vortex in the normal sinus. The bicuspid sinus vortex appears much weaker, but more unstable. Unsteady oscillatory shear stresses are also observed, which have been associated with adverse biological response; characterization of the hemodynamics of BAVs will provide the first step to understanding these processes better. Results from multiple BAV models of varying levels of stenosis will be presented & higher stenosis corresponded to stronger jets & increased aortic wall shear stresses.

  14. Generalized phase contrast:

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast...... (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than...... efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, and can even enable a Reverse Phase Contrast mode where intensity patterns are converted into a phase modulation....

  15. Generalized Phase Contrast

    CERN Document Server

    Glückstad, Jesper

    2009-01-01

    Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, ...

  16. Generalized phase contrast:

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast...... (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than...... the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light...

  17. Hemodynamics of hepatocellular carcinoma with single-level dynamic computed tomography during hepatic arteriography

    Energy Technology Data Exchange (ETDEWEB)

    Tanihata, Hirohiko [Wakayama Medical Coll. (Japan)

    2002-03-01

    The purpose of this study is to verify the hemodynamics of hepatocellular carcinoma (HCC) and to explore the draining pathway using single-level dynamic computed tomography during hepatic arteriography (single-level dynamic CTHA). One hundred one patients with 131 nodules of HCC underwent single level dynamic CTHA. Forty seven nodules were diagnosed by histological specimen and the other eighty four nodules by clinical findings of elevation in AFP and/or PIVKA II and hypervascular tumor in angiography. Single-level dynamic CTHA was performed under insertion of a catheter into proper hepatic artery or the more peripheral hepatic artery with a slice thickness of 3 mm at the same level. Each image of single level dynamic CTHA was continuously taken in a second for 40 seconds during injection of contrast medium at of 2 ml/sec for 10 seconds. The images of single-level dynamic CTHA were differentiated into three phases, as early phase 1 to 10 seconds, middle phase 11 to 20 seconds and late phase 21 to 40 seconds. After the analysis of the vascular pattern in each phase, the hemodynamics of HCC was classified into three patterns; hypovascular pattern in the 24 nodules whose average size was 13.4{+-}4.2 mm, intermediate pattern in the 21 nodules whose average size was 20.8{+-}7.8 mm and hypervascular pattern in 86 nodules whose average size was 31.6{+-}16.3 mm. There were significant correlations between the tumor size and the vascular pattern. In the groups of hypovascular and intermediate pattern, the draining pathways were sinusoids. Of the 86 nodules of the group with hypervascular pattern, blood flow drained into portal vein including bright branch structure in 20 nodules, into portal vein and hepatic vein in 2 nodules, into portal vein and extrahepatic vein in 1 nodule, into hepatic vein in 11 nodules, into extrahepatic vein in 4 nodules and into sinusoids in 48 nodules. In conclusion, from a viewpoint of hemodynamics using single-level dynamic CTHA, I proposed the

  18. Hemodynamic and neurochemical determinates of renal function in chronic heart failure.

    Science.gov (United States)

    Gilbert, Cameron; Cherney, David Z I; Parker, Andrea B; Mak, Susanna; Floras, John S; Al-Hesayen, Abdul; Parker, John D

    2016-01-15

    Abnormal renal function is common in acute and chronic congestive heart failure (CHF) and is related to the severity of congestion. However, treatment of congestion often leads to worsening renal function. Our objective was to explore basal determinants of renal function and their response to hemodynamic interventions. Thirty-seven patients without CHF and 59 patients with chronic CHF (ejection fraction; 23 ± 8%) underwent right heart catheterization, measurements of glomerular filtration rate (GFR; inulin) and renal plasma flow (RPF; para-aminohippurate), and radiotracer estimates of renal sympathetic activity. A subset (26 without, 36 with CHF) underwent acute pharmacological intervention with dobutamine or nitroprusside. We explored the relationship between baseline and drug-induced hemodynamic changes and changes in renal function. In CHF, there was an inverse relationship among right atrial mean pressure (RAM) pressure, RPF, and GFR. By contrast, mean arterial pressure (MAP), cardiac index (CI), and measures of renal sympathetic activity were not significant predictors. In those with CHF there was also an inverse relationship among the drug-induced changes in RAM as well as pulmonary artery mean pressure and the change in GFR. Changes in MAP and CI did not predict the change in GFR in those with CHF. Baseline values and changes in RAM pressure did not correlate with GFR in those without CHF. In the CHF group there was a positive correlation between RAM pressure and renal sympathetic activity. There was also an inverse relationship among RAM pressure, GFR, and RPF in patients with chronic CHF. The observation that acute reductions in RAM pressure is associated with an increase in GFR in patients with CHF has important clinical implications.

  19. Patient-specific assessment of hemodynamics by computational fluid dynamics in patients with bicuspid aortopathy.

    Science.gov (United States)

    Kimura, Naoyuki; Nakamura, Masanori; Komiya, Kenji; Nishi, Satoshi; Yamaguchi, Atsushi; Tanaka, Osamu; Misawa, Yoshio; Adachi, Hideo; Kawahito, Koji

    2017-04-01

    Hemodynamics related to eccentric blood flow may factor into the development of bicuspid aortic valve aortopathy. We investigated wall shear stress distribution by means of magnetic resonance imaging-based computational fluid dynamics in patients with a bicuspid aortic valve. Included were 12 patients with a bicuspid aortic valve (aortic stenosis, n = 11; root enlargement, n = 1). Three patients with a normal tricuspid aortic valve (arch aneurysm, n = 1; descending aortic aneurysm, n = 2) were included for comparison. The thoracic aorta geometry was reconstructed by means of 3-dimensional computed tomography angiography, and the bicuspid aortic valve orifice was modeled. Flow rates at the sinotubular junction and 3 aortic branches were measured at various time points by cine phase-contrast magnetic resonance imaging to define boundary conditions for computational fluid dynamics, and the flow was simulated. Bicuspid aortic valve cusp configurations were type 0 lateral (n = 4), type 0 anterior-posterior (n = 2), type 1 L-R (n = 4), and type 1 R-N (n = 2). Abnormal aortic helical flow was seen in the ascending aorta and transverse arch in all patients with bicuspid aortic valves and was right handed in 11 patients (91%). No such flow was seen in the patients with tricuspid aortic valves. The patients with bicuspid aortic valves were likely to have jet flow/wall impingement against the greater curvature of the proximal ascending aorta, resulting in remarkably increased wall shear stress around the impingement area. Computational fluid dynamics simulation is useful for precise evaluation of hemodynamics related to bicuspid aortic valve aortopathy. Such evaluation will advance our understanding of the disease pathophysiology and may facilitate molecular biological investigation. Copyright © 2017. Published by Elsevier Inc.

  20. Hemodynamic response to treatment of iron deficiency anemia in pulmonary arterial hypertension: longitudinal insights from an implantable hemodynamic monitor

    OpenAIRE

    Mehmood, Muddassir; Agarwal, Richa; Raina, Amresh; Correa-Jaque, Priscilla; Benza, Raymond L.

    2016-01-01

    Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) wer...

  1. Hemodynamic signal changes accompanying execution and imagery of swallowing in patients with dysphagia: A multiple single-case near-infrared spectroscopy study

    Directory of Open Access Journals (Sweden)

    Silvia Erika Kober

    2015-07-01

    Full Text Available In the present multiple case study we examined hemodynamic changes in the brain in response to motor execution (ME and motor imagery (MI of swallowing in dysphagia patients compared to healthy matched controls using near-infrared spectroscopy (NIRS. Two stroke patients with cerebral lesions in the right hemisphere, two stroke patients with lesions in the brainstem and two neurologically healthy control subjects actively swallowed saliva (ME and mentally imagined to swallow saliva (MI in a randomized order while changes in concentration of oxygenated hemoglobin (oxy-Hb and deoxygenated hemoglobin (deoxy-Hb were assessed. In line with recent findings in healthy young adults, MI and ME of swallowing led to the strongest NIRS signal change in the inferior frontal gyrus in stroke patients as well as in healthy elderly. We found differences in the topographical distribution and time course of the hemodynamic response in dependence on lesion location. Dysphagia patients with lesions in the brainstem showed bilateral hemodynamic signal changes in the inferior frontal gyrus during active swallowing comparable to healthy controls. In contrast, dysphagia patients with cerebral lesions in the right hemisphere showed more unilateral activation patterns during swallowing. Furthermore, patients with cerebral lesions showed a prolonged time course of the hemodynamic response during MI and ME of swallowing compared to healthy controls and patients with brainstem lesions. Brain activation patterns associated with ME and MI of swallowing were largely comparable, especially for changes in deoxy-Hb. Hence, the present results provide new evidence regarding timing and topographical distribution of the hemodynamic response during ME and MI of swallowing in dysphagia patients and may have practical impact on future dysphagia treatment.

  2. Obesity is not associated with contrast nephropathy

    Directory of Open Access Journals (Sweden)

    Navin Jaipaul

    2010-05-01

    Full Text Available Navin Jaipaul1, Rendell Manalo2, Seyed-Ali Sadjadi1, James McMillan11Section of Nephrology, VA Loma Linda Healthcare System, 2Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USABackground: Exposure to radiocontrast media may result in acute kidney injury (AKI or traditionally defined contrast nephropathy (CN, both of which may lead to increased morbidity and mortality. The pathogenesis of both these variants of contrast-induced nephropathy (CIN may involve inflammatory mediators that lead to renal impairment. A link between obesity and inflammation has been clearly established, but whether obesity is independently associated with CIN is unknown.Objective: To determine whether obesity, when stratified by body mass index (BMI, is a risk factor for CIN in a large and hemodynamically stable population of hospitalized United States veterans.Design: Retrospective chart review.Measurements: Presence or absence of AKI or CN after intravenous radiocontrast administration and comparison of patient characteristics between those with versus without AKI or CN.Results: The overall prevalence of AKI and CN was 16.1% and 12.6%, respectively. Patients with AKI or CN were comparable to those without radiocontrast injury, except that affected patients tended to be older and diabetic. When stratified by BMI, obesity was not found to be associated with the development of AKI or CN after exposure to radiocontrast.Conclusion: Obesity does not appear to be an independent risk factor for AKI or CN after exposure to radiocontrast.Keywords: obesity, contrast nephropathy, kidney injury

  3. Flash Infrared Thermography Contrast Data Analysis Technique

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    This paper provides information on an IR Contrast technique that involves extracting normalized contrast versus time evolutions from the flash thermography inspection infrared video data. The analysis calculates thermal measurement features from the contrast evolution. In addition, simulation of the contrast evolution is achieved through calibration on measured contrast evolutions from many flat-bottom holes in the subject material. The measurement features and the contrast simulation are used to evaluate flash thermography data in order to characterize delamination-like anomalies. The thermal measurement features relate to the anomaly characteristics. The contrast evolution simulation is matched to the measured contrast evolution over an anomaly to provide an assessment of the anomaly depth and width which correspond to the depth and diameter of the equivalent flat-bottom hole (EFBH) similar to that used as input to the simulation. A similar analysis, in terms of diameter and depth of an equivalent uniform gap (EUG) providing a best match with the measured contrast evolution, is also provided. An edge detection technique called the half-max is used to measure width and length of the anomaly. Results of the half-max width and the EFBH/EUG diameter are compared to evaluate the anomaly. The information provided here is geared towards explaining the IR Contrast technique. Results from a limited amount of validation data on reinforced carbon-carbon (RCC) hardware are included in this paper.

  4. Spleen dynamic contrast-enhanced magnetic resonance imaging as a new method for staging liver fibrosis in a piglet model.

    Directory of Open Access Journals (Sweden)

    Li Zhou

    Full Text Available OBJECTIVE: To explore spleen hemodynamic alteration in liver fibrosis with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI, and to determine how to stage liver fibrosis with spleen DCE-MRI parameters. MATERIALS AND METHODS: Sixteen piglets were prospectively used to model liver fibrosis staged by liver biopsy, and underwent spleen DCE-MRI on 0, 5th, 9th, 16th and 21st weekend after modeling this disease. DCE-MRI parameters including time to peak (TTP, positive enhancement integral (PEI, maximum slope of increase (MSI and maximum slope of decrease (MSD of spleen were measured, and statistically analyzed to stage this disease. RESULTS: Spearman's rank correlation tests showed that TTP tended to increase with increasing stages of liver fibrosis (r = 0.647, P0.05, and decreased from stage 2 to 4 (P0.05. Mann-Whitney tests demonstrated that TTP and PEI could classify fibrosis between stage 0 and 1-4, between 0-1 and 2-4, between 0-2 and 3-4, or between 0-3 and 4 (all P<0.01. MSD could discriminate between 0-2 and 3-4 (P = 0.006, or between 0-3 and 4 (P = 0.012. MSI could not differentiate between any two stages. Receiver operating characteristic analysis illustrated that area under receiver operating characteristic curve (AUC of TTP was larger than of PEI for classifying stage ≥1 and ≥2 (AUC = 0.851 and 0.783, respectively. PEI could best classify stage ≥3 and 4 (AUC = 0.903 and 0.96, respectively. CONCLUSION: Spleen DCE-MRI has potential to monitor spleen hemodynamic alteration and classify liver fibrosis stages.

  5. The Diagnosis and Hemodynamic Monitoring of Circulatory Shock: Current and Future Trends

    Directory of Open Access Journals (Sweden)

    Hendy Adham

    2016-07-01

    Full Text Available Circulatory shock is a complex clinical syndrome encompassing a group of conditions that can arise from different etiologies and presented by several different hemodynamic patterns. If not corrected, cell dysfunction, irreversible multiple organ insufficiency, and death may occur. The four basic types of shock, hypovolemic, cardiogenic, obstructive and distributive, have features similar to that of hemodynamic shock. It is therefore essential, when monitoring hemodynamic shock, to making accurate clinical assessments which will guide and dictate appropriate management therapy. The European Society of Intensive Care has recently made recommendations for monitoring hemodynamic shock. The present paper discusses the issues raised in the new statements, including individualization of blood pressure targets, prediction of fluid responsiveness, and the use of echocardiography as the first means during the initial evaluation of circulatory shock. Also, the place of more invasive hemodynamic monitoring techniques and future trends in hemodynamic and metabolic monitoring in circulatory shock, will be debated.

  6. Imaging hemodynamic effects of ET-1 on cerebral blood flow in rats

    Science.gov (United States)

    Ponticorvo, Adrien; Tom, W. J.; Aura, M.; Jones, T. A.; Dunn, A. K.

    2007-02-01

    Endothelin-1 (ET-1) is a potent vasoconstrictor sometimes used in studies of cerebral ischemia. Its ability to create ischemic regions of various sizes with little additional damage has made it a popular tool in evaluating anti-stroke drugs. Despite its emergence in stroke models, it remains poorly characterized. Attempts to do this with Laser Doppler Flowmetry (LDF) or a histological analysis provide good temporal resolution or good spatial resolution respectively, but not both. An imaging modality that provides both temporal and spatial resolution would be able to better characterize the acute and chronic effects of ET-1 on cerebral blood flow. We have used laser speckle contrast imaging to study the effects of ET-1 after topical application on rats. We observed an immediate decrease in blood flow corresponding to the amount of ET-1 used. After the initial decrease, the blood flow slowly increases towards the baseline value with occasional vasospastic responses observed. Future studies involving multi-spectral reflectance imaging combined with the laser speckle contrast analysis would lead to a better understanding of the hemodynamic effects of ET-1.

  7. Anisotropic Contrast Optical Microscope

    CERN Document Server

    Peev, D; Kananizadeh, N; Wimer, S; Rodenhausen, K B; Herzinger, C M; Kasputis, T; Pfaunmiller, E; Nguyen, A; Korlacki, R; Pannier, A; Li, Y; Schubert, E; Hage, D; Schubert, M

    2016-01-01

    An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. We demonstrate the anisotropic contrast optical microscope by mea...

  8. Electrofluidic systems for contrast management

    Science.gov (United States)

    Rebello, Keith J.; Maranchi, Jeffrey P.; Tiffany, Jason E.; Brown, Christopher Y.; Maisano, Adam J.; Hagedon, Matthew A.; Heikenfeld, Jason C.

    2012-06-01

    Operating in dynamic lighting conditions and in greatly varying backgrounds is challenging. Current paints and state-ofthe- art passive adaptive coatings (e.g. photochromics) are not suitable for multi- environment situations. A semi-active, low power, skin is needed that can adapt its reflective properties based on the background environment to minimize contrast through the development and incorporation of suitable pigment materials. Electrofluidic skins are a reflective display technology for electronic ink and paper applications. The technology is similar to that in E Ink but makes use of MEMS based microfluidic structures, instead of simple black and white ink microcapsules dispersed in clear oil. Electrofluidic skin's low power operation and fast switching speeds (~20 ms) are an improvement over current state-ofthe- art contrast management technologies. We report on a microfluidic display which utilizes diffuse pigment dispersion inks to change the contrast of the underlying substrate from 5.8% to 100%. Voltage is applied and an electromechanical pressure is used to pull a pigment dispersion based ink from a hydrophobic coated reservoir into a hydrophobic coated surface channel. When no voltage is applied, the Young-Laplace pressure pushes the pigment dispersion ink back down into the reservoir. This allows the pixel to switch from the on and off state by balancing the two pressures. Taking a systems engineering approach from the beginning of development has enabled the technology to be integrated into larger systems.

  9. Compressive Phase Contrast Tomography

    CERN Document Server

    Maia, F R N C; Marchesini, S; Padmore, H A; Parkinson, D Y; Pien, J; Schirotzek, A; Yang, C; 10.1117/12.861946

    2010-01-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher con- trast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  10. Resistance training improves hemodynamic function, collagen deposition and inflammatory profiles: experimental model of heart failure

    National Research Council Canada - National Science Library

    Alves, Jadson P; Nunes, Ramiro B; Stefani, Giuseppe P; Dal Lago, Pedro

    2014-01-01

    .... Therefore, this study evaluated the influence of a resistance training program on hemodynamic function, maximum strength gain, collagen deposition and inflammatory profile in chronic heart failure rats...

  11. Physiological responses to environmental factors related to space flight. [hemodynamic and metabolic responses to weightlessness

    Science.gov (United States)

    Pace, N.

    1973-01-01

    Physiological base line data are established, and physiological procedures and instrumentation necessary for the automatic measurement of hemodynamic and metabolic parameters during prolonged periods of weightlessness are developed.

  12. Mapping cell-specific functional connections in the mouse brain using ChR2-evoked hemodynamics (Conference Presentation)

    Science.gov (United States)

    Bauer, Adam Q.; Kraft, Andrew; Baxter, Grant A.; Bruchas, Michael; Lee, Jin-Moo; Culver, Joseph P.

    2017-02-01

    Functional magnetic resonance imaging (fMRI) has transformed our understanding of the brain's functional organization. However, mapping subunits of a functional network using hemoglobin alone presents several disadvantages. Evoked and spontaneous hemodynamic fluctuations reflect ensemble activity from several populations of neurons making it difficult to discern excitatory vs inhibitory network activity. Still, blood-based methods of brain mapping remain powerful because hemoglobin provides endogenous contrast in all mammalian brains. To add greater specificity to hemoglobin assays, we integrated optical intrinsic signal(OIS) imaging with optogenetic stimulation to create an Opto-OIS mapping tool that combines the cell-specificity of optogenetics with label-free, hemoglobin imaging. Before mapping, titrated photostimuli determined which stimulus parameters elicited linear hemodynamic responses in the cortex. Optimized stimuli were then scanned over the left hemisphere to create a set of optogenetically-defined effective connectivity (Opto-EC) maps. For many sites investigated, Opto-EC maps exhibited higher spatial specificity than those determined using spontaneous hemodynamic fluctuations. For example, resting-state functional connectivity (RS-FC) patterns exhibited widespread ipsilateral connectivity while Opto-EC maps contained distinct short- and long-range constellations of ipsilateral connectivity. Further, RS-FC maps were usually symmetric about midline while Opto-EC maps displayed more heterogeneous contralateral homotopic connectivity. Both Opto-EC and RS-FC patterns were compared to mouse connectivity data from the Allen Institute. Unlike RS-FC maps, Thy1-based maps collected in awake, behaving mice closely recapitulated the connectivity structure derived using ex vivo anatomical tracer methods. Opto-OIS mapping could be a powerful tool for understanding cellular and molecular contributions to network dynamics and processing in the mouse brain.

  13. Pros and cons of using the informed basis set to account for hemodynamic response variability with developmental data

    Directory of Open Access Journals (Sweden)

    Fabien Cignetti

    2016-07-01

    Full Text Available Conventional analysis of functional magnetic resonance imaging (fMRI data using the general linear model (GLM employs a neural model convolved with a canonical hemodynamic response function (HRF peaking 5s after stimulation. Incorporation of a further basis function, namely the canonical HRF temporal derivative, accounts for delays in the hemodynamic response to neural activity. A population that may benefit from this flexible approach is children whose hemodynamic response is not yet mature. Here, we examined the effects of using the set based on the canonical HRF plus its temporal derivative on both first- and second-level GLM analyses, through simulations and using developmental data (an fMRI dataset on proprioceptive mapping in children and adults. Simulations of delayed fMRI first-level data emphasized the benefit of carrying forward to the second-level a derivative boost that combines derivative and nonderivative beta estimates. In the experimental data, second-level analysis using a paired t-test showed increased mean amplitude estimate (i.e., increased group contrast mean in several brain regions related to proprioceptive processing when using the derivative boost compared to using only the nonderivative term. This was true especially in children. However, carrying forward to the second-level the individual derivative boosts had adverse consequences on random-effects analysis that implemented one-sample t-test, yielding increased between-subject variance, thus affecting group-level statistic. Boosted data also presented a lower level of smoothness that had implication for the detection of group average activation. Imposing soft constraints on the derivative boost by limiting the time-to-peak range of the modelled response within a specified range (i.e., 4-6s mitigated these issues. These findings support the notion that there are pros and cons to using the informed basis set with developmental data.

  14. BOLD-based Techniques for Quantifying Brain Hemodynamic and Metabolic Properties – Theoretical Models and Experimental Approaches

    Science.gov (United States)

    Yablonskiy, Dmitriy A.; Sukstanskii, Alexander L.; He, Xiang

    2012-01-01

    Quantitative evaluation of brain hemodynamics and metabolism, particularly the relationship between brain function and oxygen utilization, is important for understanding normal human brain operation as well as pathophysiology of neurological disorders. It can also be of great importance for evaluation of hypoxia within tumors of the brain and other organs. A fundamental discovery by Ogawa and co-workers of the BOLD (Blood Oxygenation Level Dependent) contrast opened a possibility to use this effect to study brain hemodynamic and metabolic properties by means of MRI measurements. Such measurements require developing theoretical models connecting MRI signal to brain structure and functioning and designing experimental techniques allowing MR measurements of salient features of theoretical models. In our review we discuss several such theoretical models and experimental methods for quantification brain hemodynamic and metabolic properties. Our review aims mostly at methods for measuring oxygen extraction fraction, OEF, based on measuring blood oxygenation level. Combining measurement of OEF with measurement of CBF allows evaluation of oxygen consumption, CMRO2. We first consider in detail magnetic properties of blood – magnetic susceptibility, MR relaxation and theoretical models of intravascular contribution to MR signal under different experimental conditions. Then, we describe a “through-space” effect – the influence of inhomogeneous magnetic fields, created in the extravascular space by intravascular deoxygenated blood, on the MR signal formation. Further we describe several experimental techniques taking advantage of these theoretical models. Some of these techniques - MR susceptometry, and T2-based quantification of oxygen OEF – utilize intravascular MR signal. Another technique – qBOLD – evaluates OEF by making use of through-space effects. In this review we targeted both scientists just entering the MR field and more experienced MR researchers

  15. Pros and Cons of Using the Informed Basis Set to Account for Hemodynamic Response Variability with Developmental Data.

    Science.gov (United States)

    Cignetti, Fabien; Salvia, Emilie; Anton, Jean-Luc; Grosbras, Marie-Hélène; Assaiante, Christine

    2016-01-01

    Conventional analysis of functional magnetic resonance imaging (fMRI) data using the general linear model (GLM) employs a neural model convolved with a canonical hemodynamic response function (HRF) peaking 5 s after stimulation. Incorporation of a further basis function, namely the canonical HRF temporal derivative, accounts for delays in the hemodynamic response to neural activity. A population that may benefit from this flexible approach is children whose hemodynamic response is not yet mature. Here, we examined the effects of using the set based on the canonical HRF plus its temporal derivative on both first- and second-level GLM analyses, through simulations and using developmental data (an fMRI dataset on proprioceptive mapping in children and adults). Simulations of delayed fMRI first-level data emphasized the benefit of carrying forward to the second-level a derivative boost that combines derivative and nonderivative beta estimates. In the experimental data, second-level analysis using a paired t-test showed increased mean amplitude estimate (i.e., increased group contrast mean) in several brain regions related to proprioceptive processing when using the derivative boost compared to using only the nonderivative term. This was true especially in children. However, carrying forward to the second-level the individual derivative boosts had adverse consequences on random-effects analysis that implemented one-sample t-test, yielding increased between-subject variance, thus affecting group-level statistic. Boosted data also presented a lower level of smoothness that had implication for the detection of group average activation. Imposing soft constraints on the derivative boost by limiting the time-to-peak range of the modeled response within a specified range (i.e., 4-6 s) mitigated these issues. These findings support the notion that there are pros and cons to using the informed basis set with developmental data.

  16. Hemodynamic responses in amygdala and hippocampus distinguish between aversive and neutral cues during Pavlovian fear conditioning in behaving rats.

    Science.gov (United States)

    McHugh, Stephen B; Marques-Smith, Andre; Li, Jennifer; Rawlins, J N P; Lowry, John; Conway, Michael; Gilmour, Gary; Tricklebank, Mark; Bannerman, David M

    2013-02-01

    Lesion and electrophysiological studies in rodents have identified the amygdala and hippocampus (HPC) as key structures for Pavlovian fear conditioning, but human functional neuroimaging studies have not consistently found activation of these structures. This could be because hemodynamic responses cannot detect the sparse neuronal activity proposed to underlie conditioned fear. Alternatively, differences in experimental design or fear levels could account for the discrepant findings between rodents and humans. To help distinguish between these alternatives, we used tissue oxygen amperometry to record hemodynamic responses from the basolateral amygdala (BLA), dorsal HPC (dHPC) and ventral HPC (vHPC) in freely-moving rats during the acquisition and extinction of conditioned fear. To enable specific comparison with human studies we used a discriminative paradigm, with one auditory cue [conditioned stimulus (CS)+] that was always followed by footshock, and another auditory cue (CS-) that was never followed by footshock. BLA tissue oxygen signals were significantly higher during CS+ than CS- trials during training and early extinction. In contrast, they were lower during CS+ than CS- trials by the end of extinction. dHPC and vHPC tissue oxygen signals were significantly lower during CS+ than CS- trials throughout extinction. Thus, hemodynamic signals in the amygdala and HPC can detect the different patterns of neuronal activity evoked by threatening vs. neutral stimuli during fear conditioning. Discrepant neuroimaging findings may be due to differences in experimental design and/or fear levels evoked in participants. Our methodology offers a way to improve translation between rodent models and human neuroimaging.

  17. Central and regional hemodynamics in prolonged space flights

    Science.gov (United States)

    Gazenko, O. G.; Shulzhenko, E. B.; Turchaninova, V. F.; Egorov, A. D.

    This paper presents the results of measuring central and regional (head, forearm, calf) hemodynamics at rest and during provocative tests by the method of tetrapolar rheography in the course of Salyut-6-Soyuz and Salyut-7-Soyuz missions. The measurements were carried out during short-term (19 man-flights of 7 days in duration) and long-term (21 man-flights of 65-237 days in duration) manned missions. At rest, stroke volume (SV) and cardiac output (CO) as well as heart rate (HR) decreased insignificantly (in short-term flights) or remained essentially unchanged (in long-term flights). In prolonged flights CO increased significantly in response to exercise tests due to an increase in HR and the lack of changes in SV. After exercise tests SV and CO decreased as compared to the preflight level. During lower body negative pressure (LBNP) tests HR and CO were slightly higher than preflight. Changes in regional hemodynamics included a distinct decrease of pulse blood filling (PBF) of the calf, a reduction of the tone of large vessels of the calf and small vessels of the forearm. Head examination (in the region of the internal carotid artery) showed a decrease of PBF of the left hemisphere (during flight months 2-8) and a distinct decline of the tone of small vessels, mainly, in the right hemisphere. During LBNP tests the tone of pre- and postcapillary vessels of the brain returned to normal while PBF of the right and left hemisphere vessels declined. It has been shown that regional circulation variations depend on the area examined and are induced by a rearrangement of total hemodynamics of the human body in microgravity. This paper reviews the data concerning changes in central and regional circulation of men in space flights of different duration.

  18. Optical imaging of neural and hemodynamic brain activity

    Science.gov (United States)

    Schei, Jennifer Lynn

    Optical imaging technologies can be used to record neural and hemodynamic activity. Neural activity elicits physiological changes that alter the optical tissue properties. Specifically, changes in polarized light are concomitant with neural depolarization. We measured polarization changes from an isolated lobster nerve during action potential propagation using both reflected and transmitted light. In transmission mode, polarization changes were largest throughout the center of the nerve, suggesting that most of the optical signal arose from the inner nerve bundle. In reflection mode, polarization changes were largest near the edges, suggesting that most of the optical signal arose from the outer sheath. To overcome irregular cell orientation found in the brain, we measured polarization changes from a nerve tied in a knot. Our results show that neural activation produces polarization changes that can be imaged even without regular cell orientations. Neural activation expends energy resources and elicits metabolic delivery through blood vessel dilation, increasing blood flow and volume. We used spectroscopic imaging techniques combined with electrophysiological measurements to record evoked neural and hemodynamic responses from the auditory cortex of the rat. By using implantable optics, we measured responses across natural wake and sleep states, as well as responses following different amounts of sleep deprivation. During quiet sleep, evoked metabolic responses were larger compared to wake, perhaps because blood vessels were more compliant. When animals were sleep deprived, evoked hemodynamic responses were smaller following longer periods of deprivation. These results suggest that prolonged neural activity through sleep deprivation may diminish vascular compliance as indicated by the blunted vascular response. Subsequent sleep may allow vessels to relax, restoring their ability to deliver blood. These results also suggest that severe sleep deprivation or chronic

  19. Hemodynamic responses to orotracheal intubation with a video laryngoscope

    Directory of Open Access Journals (Sweden)

    Shahnaz Shayeghi

    2007-10-01

    Full Text Available Background: Differences in airway anatomy make the potential for technical airway difficulties greater in infants than in
    teenagers or adults. Endotracheal intubation by direct vision using a laryngoscope is frequently associated with an increase
    in arterial blood pressure and heart rate. In different studies, the time to intubation with a video laryngoscope was
    longer than with direct laryngoscopy using Macintosh, and this longer duration may be accompanied by more hemodynamic
    responses.
    METHODS: Sixty-four infants who were scheduled for elective surgery requiring general anesthesia with orotracheal
    intubation were randomly assigned to intubation by direct laryngoscopy using a Macintosh size 1 blade or to intubation
    using a video laryngoscope. Systolic and diastolic blood pressures, heart rate and oxygen saturation were recorded at the
    following time points: (1 before induction, (2 after induction and before intubation, and (3 1 minute and (4 5 minutes
    after intubation.
    RESULTS: No significant differences were found either between the two groups or among the different study periods.
    The duration for laryngoscopy and intubation with a video laryngoscope was 20.87 ± 7.95 seconds (mean ± standard
    deviation and that with Macintosh was 15.41 ± 4.1 seconds (P < 0.01.
    CONCLUSIONS: Similar hemodynamic responses in both groups suggest that laryngoscopy and intubation with a video
    laryngoscope, although with longer duration and therefore resulting in more stimulation, has no significant effect on
    hemodynamic status and oxygen saturation in infants.
    KEY WORDS: Video laryngoscope, laryngoscopy, blood pressure, heart rate

  20. Hemodynamic changes after levothyroxine treatment in subclinical hypothyroidism

    DEFF Research Database (Denmark)

    Faber, J; Petersen, L; Wiinberg, N

    2002-01-01

    In hypothyroidism, lack of thyroid hormones results in reduced cardiac function (cardiac output [CO]), and an increase of systemic vascular resistance (SVR). We speculated whether hemodynamic regulation in subjects with subclinical hypothyroidism (SH) (defined as mildly elevated thyrotropin [TSH.......05). These changes were qualitatively similar but quantitatively less pronounced than in 15 women with overt hypothyroidism, also studied. Taking the two groups together (n = 31), pretreatment thyroid function (expressed as either TSH or free T(4) estimate) correlated to CO and SVR as well as the changes induced...... by LT(4) (p hypothyroidism should...

  1. Hemodynamics and annuloplasty in isolated mitral regurgitation in children.

    Science.gov (United States)

    Sulayman, R; Mathew, R; Thilenius, O G; Replogle, R; Arcilla, R A

    1975-12-01

    Isolated mitral insufficiency in children is quantitated angiographically by comparing the stroke volumes of the right ventricle and left ventricle. The disease results in greater enlargement of the left atrium than of the left ventricle and is accompanied by a significant increase in left atrial "distensibility." Right and left heart pressures may be normal or may be increased; they tend to be elevated in the group with regurgitant fractions of over 50%. Annuloplasty results in marked clinical and hemodynamic improvement and may even be corrective.

  2. A sliding mode observer for hemodynamic characterization under modeling uncertainties

    KAUST Repository

    Zayane, Chadia

    2014-06-01

    This paper addresses the case of physiological states reconstruction in a small region of the brain under modeling uncertainties. The misunderstood coupling between the cerebral blood volume and the oxygen extraction fraction has lead to a partial knowledge of the so-called balloon model describing the hemodynamic behavior of the brain. To overcome this difficulty, a High Order Sliding Mode observer is applied to the balloon system, where the unknown coupling is considered as an internal perturbation. The effectiveness of the proposed method is illustrated through a set of synthetic data that mimic fMRI experiments.

  3. From hemodynamic towards cardiomechanic sensors in implantable devices

    Science.gov (United States)

    Ferek-Petric, Bozidar

    2013-06-01

    Sensor could significantly improve the cardiac electrotherapy. It has to provide long-term stabile signal not impeding the device longevity and lead reliability. It may not introduce special implantation and adjustment procedures. Hemodynamic sensors based on the blood flow velocity and cardiomechanic sensors based on the lead bending measurement are disclosed. These sensors have a broad clinical utility. Triboelectric and high-frequency lead bending sensors yield accurate and stable signals whereby functioning with every cardiac lead. Moreover, high frequency measurement avoids use of any kind of special hardware mounted on the cardiac lead.

  4. Study on hemodynamics in patient-specific thoracic aortic aneurysm

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The objective of this study is to investigate the hemodynamics in patient-specific thoracic aortic aneurysm and discuss the reason for formation of aortic plaque.A 3-Dimensional pulsatile blood flow in thoracic aorta with a fusiform aneurysm and 3 main branched vessels was studied numerically with the average Reynolds number of 1399 and the Womersley number of 19.2.Based on the clinical 2-Dimensional CT slice data,the patient-specific geometry model was constructed using medical image process software.Un...

  5. Cerebral hemodynamic and metabolic changes in fulminant hepatic failure

    Directory of Open Access Journals (Sweden)

    Fernando Mendes Paschoal Junior

    Full Text Available ABSTRACT Intracranial hypertension and brain swelling are a major cause of morbidity and mortality of patients suffering from fulminant hepatic failure (FHF. The pathogenesis of these complications has been investigated in man, in experimental models and in isolated cell systems. Currently, the mechanism underlying cerebral edema and intracranial hypertension in the presence of FHF is multi-factorial in etiology and only partially understood. The aim of this paper is to review the pathophysiology of cerebral hemodynamic and metabolism changes in FHF in order to improve understanding of intracranial dynamics complication in FHF.

  6. Effects of Dietary Nitrates on Systemic and Cerebrovascular Hemodynamics

    Directory of Open Access Journals (Sweden)

    Vernon Bond

    2013-01-01

    Full Text Available Cerebral blood flow dysregulation is often associated with hypertension. We hypothesized that a beetroot juice (BRJ treatment could decrease blood pressure and cerebrovascular resistance (CVR. We subjected 12 healthy females to control and BRJ treatments. Cerebrovascular resistance index (CVRI, systolic blood pressure (SBP, total vascular resistance (TVR, and the heart rate-systolic pressure product (RPP measured at rest and at two exercise workloads were lower after the BRJ treatment. CVRI, SBP, and RPP were lower without a lower TVR at the highest exercise level. These findings suggest improved systemic and cerebral hemodynamics that could translate into a dietary treatment for hypertension.

  7. Vascular aging and hemodynamic stability in the intraoperative period

    Directory of Open Access Journals (Sweden)

    Ferrante S. Gragasin

    2012-04-01

    Full Text Available The proportion of elderly people in the population is steadily increasing, and the inevitable consequence is that this subpopulation is more frequently represented in common medical procedures and surgeries. Understanding the circulatory changes that accompany the aging process is therefore becoming increasingly timely and relevant. In this short review, we discuss aspects of vascular control in aging that are particularly relevant in the maintenance of intraoperative hemodynamic stability. We subsequently review the effects of certain notable anesthetic agents with respect to the aging vasculature.

  8. Clitoral hemodynamic changes after a topical application of alprostadil.

    Science.gov (United States)

    Becher, E F; Bechara, A; Casabe, A

    2001-01-01

    We performed duplex ultrasonography of the clitoris to assess the local hemodynamic changes after a topical application of alprostadil. Color duplex ultrasonography was used to evaluate 18 women before and after the application of 1 g of 0.2% alprostadil gel. The peak systolic velocity and end diastolic velocity showed a statistically significant difference after the application. All women showed labial and clitoral engorgement, 72% reported a pleasant sensation of warmth, and no systemic side effects were found. These findings are similar to the values reported after sexual stimulation, indicating that topical vasoactive drugs might help in the differential diagnosis of the vascular component of female sexual dysfunction.

  9. Right ventricular Hemodynamic Alteration after Pulmonary Valve Replacement in Children with Congenital Heart Disease

    Directory of Open Access Journals (Sweden)

    Hamid Bigdelian

    2015-03-01

    Full Text Available Introduction:  In patients who underwent surgery to repair Tetralogy of Fallot, right ventricular dilation from pulmonary regurgitation may be result in right ventricular failure, arrhythmias and cardiac arrest. Hence, pulmonary valve replacement may be necessary to reduce right ventricular volume overload. The aim of present study was to assess the effects of pulmonary valve replacement on right ventricular function after repair of Tetralogy of Fallot.   Materials and  Method:  This retrospective study was carried out between July 2011 and October 2013 on 21 consecutive patients in Chamran Heart Center (Esfahan. The study included 13 male (61.9% and 8 female (38.1%. Cardiac magnetic resonance was performed before, 6 and 12 months after pulmonary valve replacement in all patients (Babak Imaging Center, Tehran with the 1.5 Tesla system. The main reason for surgery at Tetralogy of Fallot repaired time was Tetralogy of Fallot + Pulmonary insufficiency (17 cases and Tetralogy of Fallot + Pulmonary atresia (4 cases. Right ventricular function was assessed before and after pulmonary valve replacement with Two-dimensional echocardiography and ttest was used to evaluate follow-up data.   Results:  Right ventricular end-diastolic volume, right ventricular end- systolic volume significantly decreased (P value ˂ 0.05.Right ventricular ejection fraction had a significant increase (P value ˂ 0.05. Right ventricular mass substantially shrank after pulmonary valve replacement. Moreover, pulmonary regurgitation noticeably decreased in patients. The other hemodynamic parameter such as left ventricular ejection fraction improved but was not significant (P value= 0.79. Conclusion:  Pulmonary valve replacement can successfully restores the impaired hemodynamic function of right ventricle which is caused by direct consequence of volume unloading in patient. Pulmonary valve surgery in children with Tetralogy of Fallot who have moderate to severe pulmonary

  10. Hyperoxia Improves Hemodynamic Status During Head-up Tilt Testing in Healthy Volunteers: A Randomized Study.

    Science.gov (United States)

    Fromonot, Julien; Chaumet, Guillaume; Gavarry, Olivier; Rostain, Jean-Claude; Lucciano, Michel; Joulia, Fabrice; Brignole, Michele; Deharo, Jean-Claude; Guieu, Regis; Boussuges, Alain

    2016-02-01

    Head-up tilt test is useful for exploring neurally mediated syncope. Adenosine is an ATP derivative implicated in cardiovascular disturbances that occur during head-up tilt test. The aim of the present study was to investigate the impact of hyperoxia on adenosine plasma level and on hemodynamic changes induced by head-up tilt testing.Seventeen healthy male volunteers (mean age 35 ± 11 years) were included in the study. The experiment consisted of 2 head-up tilt tests, 1 session with subjects breathing, through a mask, medical air (FiO2 = 21%) and 1 session with administration of pure oxygen (FiO2 = 100%) in double-blind manner. Investigations included continuous monitoring of hemodynamic data and measurement of plasma adenosine levels.No presyncope or syncope was found in 15 of the 17 volunteers. In these subjects, a slight decrease in systolic blood pressure was recorded during orthostatic stress performed under medical air exposure. In contrast, hyperoxia led to increased systolic blood pressure during orthostatic stress when compared with medical air. Furthermore, mean adenosine plasma levels decreased during hyperoxic exposure before (0.31 ± 0.08 μM) and during head-up tilt test (0.33 ± 0.09 μM) when compared with baseline (0.6 ± 0.1 μM). Adenosine plasma level was unchanged during medical air exposure at rest (0.6 ± 0.1 μM), and slightly decreased during orthostatic stress. In 2 volunteers, the head-up tilt test induced a loss of consciousness when breathing air. In these subjects, adenosine plasma level increased during orthostatic stress. In contrast, during hyperoxic exposure, the head-up tilt test did not induce presyncope or syncope. In these 2 volunteers, biological study demonstrated a decrease in adenosine plasma level at both baseline and during orthostatic stress for hyperoxic exposure compared with medical air.These results suggest that hyperoxia was able to increase blood pressure during head-up tilt

  11. Preliminary assessing no-surgical treatment response in bronchogenic carcinoma with double-phase contrast material-enhanced computed tomography%CT增强双期扫描在肺癌非手术治疗疗效评价中的初步研究

    Institute of Scientific and Technical Information of China (English)

    Shenjiang Li; Yong Zhao; Yan Zhu; Feng Zhu; Debin Liu; Wenjie Liang; Xuefeng Cui; Wenjie Bi

    2009-01-01

    Objective: To evaluate the efficacy of double-phase contrast material-enhanced computed tomography (CT) in assessing no-surgical treatment response in bronchogenic carcinoma preliminarily. Methods: 52 patients with bronchogenic carcinoma after no-surgical treatment underwent double-phase contrast material-enhanced computed tomography. Two spiral CT scans were obtained at 25 and 90 seconds respectively after nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/s by using an autoinjector. Precontrast and postcontrast attenuation on every scan was recorded and peak height was calculated. Enhancement pattern was evaluated on the images obtained at 25 and 90 seconds after injection of contrast medium. Results: Precontrast attenuation, postcontrast attenuation at 25 and 90 seconds were 42.20±7.43 Hu, 57.35 ± 10.09 Hu and 71.85 ± 12.45 Hu, respectively. No statistically significant difference in precontrast attenuation was found between our results in the study and the results in our old study (mean precontrast attenuation 40.70 Hu) which was obtained in cases before therapy (t = 1.455, P = 0.152 > 0.05). Peak height of bronchogenic carcinoma after no-surgical treatment (29.46 ± 10.85 Hu) were significantly lower than that of bronchogenic carcinoma before therapy obtained in our old study (mean peak height 35.79 Hu; t = 4.206, P = 0.001 < 0.05). 32 of 52 cases showed homogeneous enhancement at 90 seconds. Of the 32 cases, there were 21 with inhomogeneous enhancement, 7 with inhomogeneous enhancement, 2 with central enhancement and 2 with peripheral enhancement at 25 seconds. Conclusion: Bronchogenic carcinoma after no-surgical treatment shows a gradual increase to the peak height after administration of contrast material. Peak heights can reflect the blood supply of bronchogenic carcinoma and might be index for evaluation of no-surgical treatment response in bronchogenic carcinoma.

  12. Potential use of microbubbles (MBs) as contrast material in x-ray dark field (DF) imaging: How does the DF signal change with the characteristic parameters of the MBs?

    Science.gov (United States)

    Zhang, Ran; Qin, Bin; Ge, Yongshuai; Whiting, Bruce; Li, Ke; Villanueva, Flordeliza; Chen, Guang-Hong

    2016-03-01

    One of the most exciting aspects of the grating based x-ray differential phase contrast (DPC) acquisition method is the concurrent generation of the so-called dark field (DF) signal, along with the classical absorption signal and the novel DPC signal. The DF signal is associated with local distribution of small angle scatterers in an image object, while the absorption signal and DPC signal are often used to characterize the relatively uniform structure of the image object. Besides the endogenous image contrast, exogenous contrast media are often used in x-ray imaging to locally enhance the image signal. This paper proposes a potential contrast medium for DF signal enhancement: microbubbles (MBs). MBs have already been developed for clinical use in ultrasound imaging, and recent experimental studies have shown that MBs may also enhance the DF signal, although it remained unclear how the physical characteristics of the MBs quantitatively impact the DF signal. In this paper, a systematic study was performed to investigate the quantitative relationships between the DF signal and the following properties of MBs: size, concentration, shell thickness, size uniformity, and whether gold nanoparticles were attached. The experimental results demonstrated that, an increased MB size (about 4 microns) may generate a stronger DF signal for our DPC imaging system; additionally, a moderately increased shell thickness and the use of gold nanoparticles on the shell surface also resulted in further enhancement of the DF signal. These findings may provide critical information needed for using MBs as the contrast agent of x-ray DF imaging.

  13. Polychromatic diffraction contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    King, A., E-mail: king@synchrotron-soleil.fr [Synchrotron SOLEIL, Gif-sur-Yvette 91192 (France); Reischig, P. [Xnovo Technology ApS, 4600 Køge (Denmark); Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD (Netherlands); Adrien, J. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); Peetermans, S. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Ludwig, W. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); European Synchrotron Radiation Facility, Grenoble 38043 (France)

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  14. Contrastive topics decomposed

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2012-12-01

    Full Text Available The analysis of contrastive topics introduced in Büring 1997b and further developed in Büring 2003 relies on distinguishing two types of constituents that introduce alternatives: the sentence focus, which is marked by a FOC feature, and the contrastive topic, which is marked by a CT feature. A non-compositional rule of interpretation that refers to these features is used to derive a topic semantic value, a nested set of sets of propositions. This paper presents evidence for a correlation between the restrictive syntax of nested focus operators and the syntax of contrastive topics, a correlation which is unexpected under this analysis. A compositional analysis is proposed that only makes use of the flatter focus semantic values introduced by focus operators. The analysis aims at integrating insights from the original analysis while at the same time capturing the observed syntactic restrictions. http://dx.doi.org/10.3765/sp.5.8 BibTeX info

  15. Hemodynamic simulations in coronary aneurysms of children with Kawasaki disease

    Science.gov (United States)

    Sengupta, Dibyendu; Burns, Jane; Marsden, Alison

    2009-11-01

    Kawasaki disease (KD) is a serious pediatric illness affecting the cardiovascular system. One of the most serious complications of KD, occurring in about 25% of untreated cases, is the formation of large aneurysms in the coronary arteries, which put patients at risk for myocardial infarction. In this project we performed patient specific computational simulations of blood flow in aneurysmal left and right coronary arteries of a KD patient to gain an understanding about their hemodynamics. Models were constructed from CT data using custom software. Typical pulsatile flow waveforms were applied at the model inlets, while resistance and RCR lumped models were applied and compared at the outlets. Simulated pressure waveforms compared well with typical physiologic data. High wall shear stress values are found in the narrow region at the base of the aneurysm and low shear values occur in regions of recirculation. A Lagrangian approach has been adopted to perform particle tracking and compute particle residence time in the recirculation. Our long-term goal will be to develop links between hemodynamics and the risk for thrombus formation in order to assist in clinical decision-making.

  16. Closed-Loop Dynamic Modeling of Cerebral Hemodynamics

    Science.gov (United States)

    Marmarelis, V. Z.; Shin, D. C.; Orme, M. E.; Zhang, R.

    2013-01-01

    The dynamics of cerebral hemodynamics have been studied extensively because of their fundamental physiological and clinical importance. In particular, the dynamic processes of cerebral flow autoregulation and CO2 vasomotor reactivity have attracted broad attention because of their involvement in a host of pathologies and clinical conditions (e.g. hypertension, syncope, stroke, traumatic brain injury, vascular dementia, Alzheimer’s disease, mild cognitive impairment etc.). This raises the prospect of useful diagnostic methods being developed on the basis of quantitative models of cerebral hemodynamics, if cerebral vascular dysfunction can be quantified reliably from data collected within practical clinical constraints. This paper presents a modeling method that utilizes beat-to-beat measurements of mean arterial blood pressure, cerebral blood flow velocity and end-tidal CO2 (collected non-invasively under resting conditions) to quantify the dynamics of cerebral flow autoregulation (CFA) and cerebral vasomotor reactivity (CVMR). The unique and novel aspect of this dynamic model is that it is nonlinear and operates in a closed-loop configuration. PMID:23292615

  17. Immediate hemodynamic response to furosemide in patients undergoing chronic hemodialysis.

    Science.gov (United States)

    Schmieder, R E; Messerli, F H; deCarvalho, J G; Husserl, F E

    1987-01-01

    To evaluate the effect of furosemide on cardiovascular hemodynamics in patients with end-stage renal failure, we studied ten patients undergoing hemodialysis three times a week. Arterial pressure, heart rate, and cardiac output (indocyanine green dye) were measured in triplicate; total peripheral resistance and central blood volume were calculated by standard formulas. Hemodynamics were determined at baseline and 5, 10, 15, and 30 minutes after intravenous (IV) bolus injection of furosemide 60 mg. Furosemide produced a decrease in central blood volume of -13% +/- 2.2% from pretreatment values (P less than .01) that was most pronounced five minutes after injection, together with a fall in cardiac output (from 6.76 +/- 0.59 to 6.17 +/- 0.52 L/min, P less than .10). Stroke volume decreased with a maximum fall occurring after 15 minutes (from 84 +/- 7 to 79 +/- 7 mL/min, P less than .05), and total peripheral resistance increased (from 15.8 +/- 2.1 to 17.8 +/- 2.3 units, P less than .05) after furosemide. Arterial pressure and heart rate did not change. The decrease in central blood volume reflects a shift of the total blood volume from the cardiopulmonary circulation to the periphery, suggesting dilation of the peripheral venous bed. Thus, even in patients undergoing hemodialysis, furosemide acutely decreases left ventricular preload by venous dilation and should therefore prove to be beneficial in acute volume overload.

  18. Prefrontal Hemodynamic Changes Associated with Subjective Sense of Occlusal Discomfort

    Directory of Open Access Journals (Sweden)

    Yumie Ono

    2015-01-01

    Full Text Available We used functional near-infrared spectroscopy to measure prefrontal brain activity accompanying the physical sensation of oral discomfort that arose when healthy young-adult volunteers performed a grinding motion with mild occlusal elevation (96 μm. We simultaneously evaluated various forms of occlusal discomfort using the visual analogue scale (VAS and hemodynamic responses to identify the specific prefrontal activity that occurs with increased occlusal discomfort. The Oxy-Hb responses of selected channels in the bilateral frontopolar and dorsolateral prefrontal cortices increased in participants who reported increased severity of occlusal discomfort, while they decreased in those who reported no change or decreased occlusal discomfort during grinding. Moreover, the cumulative values of Oxy-Hb response in some of these channels were statistically significant predictive factors for the VAS scores. A generalized linear model analysis of Oxy-Hb signals in a group of participants who reported increased discomfort further indicated significant cerebral activation in the right frontopolar and dorsolateral prefrontal cortices that overlapped with the results of correlation analyses. Our results suggest that the increased hemodynamic responses in the prefrontal area reflect the top-down control of attention and/or self-regulation against the uncomfortable somatosensory input, which could be a possible marker to detect the subjective sense of occlusal discomfort.

  19. Bioimpedance Measurement of Segmental Fluid Volumes and Hemodynamics

    Science.gov (United States)

    Montgomery, Leslie D.; Wu, Yi-Chang; Ku, Yu-Tsuan E.; Gerth, Wayne A.; DeVincenzi, D. (Technical Monitor)

    2000-01-01

    Bioimpedance has become a useful tool to measure changes in body fluid compartment volumes. An Electrical Impedance Spectroscopic (EIS) system is described that extends the capabilities of conventional fixed frequency impedance plethysmographic (IPG) methods to allow examination of the redistribution of fluids between the intracellular and extracellular compartments of body segments. The combination of EIS and IPG techniques was evaluated in the human calf, thigh, and torso segments of eight healthy men during 90 minutes of six degree head-down tilt (HDT). After 90 minutes HDT the calf and thigh segments significantly (P < 0.05) lost conductive volume (eight and four percent, respectively) while the torso significantly (P < 0.05) gained volume (approximately three percent). Hemodynamic responses calculated from pulsatile IPG data also showed a segmental pattern consistent with vascular fluid loss from the lower extremities and vascular engorgement in the torso. Lumped-parameter equivalent circuit analyses of EIS data for the calf and thigh indicated that the overall volume decreases in these segments arose from reduced extracellular volume that was not completely balanced by increased intracellular volume. The combined use of IPG and EIS techniques enables noninvasive tracking of multi-segment volumetric and hemodynamic responses to environmental and physiological stresses.

  20. Effect of Outflow Tract Banding on Embryonic Cardiac Hemodynamics

    Directory of Open Access Journals (Sweden)

    Venkat Keshav Chivukula

    2015-12-01

    Full Text Available We analyzed heart wall motion and blood flow dynamics in chicken embryos using in vivo optical coherence tomography (OCT imaging and computational fluid dynamics (CFD embryo-specific modeling. We focused on the heart outflow tract (OFT region of day 3 embryos, and compared normal (control conditions to conditions after performing an OFT banding intervention, which alters hemodynamics in the embryonic heart and vasculature. We found that hemodynamics and cardiac wall motion in the OFT are affected by banding in ways that might not be intuitive a priori. In addition to the expected increase in ventricular blood pressure, and increase blood flow velocity and, thus, wall shear stress (WSS at the band site, the characteristic peristaltic-like motion of the OFT was altered, further affecting flow and WSS. Myocardial contractility, however, was affected only close to the band site due to the physical restriction on wall motion imposed by the band. WSS were heterogeneously distributed in both normal and banded OFTs. Our results show how banding affects cardiac mechanics and can lead, in the future, to a better understanding of mechanisms by which altered blood flow conditions affect cardiac development leading to congenital heart disease.

  1. A Liquid-Solid Coupling Hemodynamic Model with Microcirculation Load

    Directory of Open Access Journals (Sweden)

    Bai Li

    2016-01-01

    Full Text Available From the aspect of human circulation system structure, a complete hemodynamic model requires consideration of the influence of microcirculation load effect. This paper selected the seepage in porous media as the simulant of microcirculation load. On the basis of a bi-directional liquid-solid coupling tube model, we built a liquid-solid-porous media seepage coupling model. The simulation parameters accorded with the physiological reality. Inlet condition was set as transient single-pulse velocity, and outlet as free outlet. The pressure in the tube was kept at the state of dynamic stability in the range of 80–120 mmHg. The model was able to simulate the entire propagating process of pulse wave. The pulse wave velocity simulated was 6.25 m/s, which accorded with the physiological reality. The complex pressure wave shape produced by reflections of pressure wave was also observed. After the model changed the cardiac cycle length, the pressure change according with actual human physiology was simulated successfully. The model in this paper is well-developed and reliable. It demonstrates the importance of microcirculation load in hemodynamic model. Moreover the properties of the model provide a possibility for the simulation of dynamic adjustment process of human circulation system, which indicates a promising prospect in clinical application.

  2. Tempol improves renal hemodynamics and pressure natriuresis in hyperthyroid rats.

    Science.gov (United States)

    Moreno, Juan Manuel; Rodríguez Gómez, Isabel; Wangensteen, Rosemary; Alvarez-Guerra, Miriam; de Dios Luna, Juan; García-Estañ, Joaquín; Vargas, Félix

    2008-03-01

    Hyperthyroidism in rats is associated with increased oxidative stress. These animals also show abnormal renal hemodynamics and an attenuated pressure-diuresis-natriuresis (PDN) response. We analyzed the role of oxidative stress as a mediator of these alterations by examining acute effects of tempol, a superoxide dismutase mimetic. The effects of increasing bolus doses of tempol (25-150 micromol/kg) on mean arterial pressure (MAP), renal vascular resistance (RVR), and cortical (CBF) and medullary (MBF) blood flow were studied in control and thyroxine (T4)-treated rats. In another experiment, tempol was infused at 150 micromol.kg(-1).h(-1) to analyze its effects on the glomerular filtration rate (GFR) and on PDN response in these animals. Tempol dose dependently decreased MAP and RVR and increased CBF and MBF in control and T4-treated rats, but the T4 group showed a greater responsiveness to tempol in all of these variables. The highest dose of tempol decreased RVR by 13.5 +/- 2.1 and 5.5 +/- 1.2 mmHg.ml(-1).min(-1) in hyperthyroid (P natriuresis (T4+tempol: 0.17 +/- 0.05; T4: 0.09 +/- 0.03 microeq.min(-1).g(-1).mmHg(-1); P < 0.05) and reduced 8-isoprostane excretion in hyperthyroid rats. These results show that antioxidant treatment with tempol improves renal hemodynamic variables and PDN response in hyperthyroid rats, indicating the participation of an increased oxidative stress in these mechanisms.

  3. Hemodynamic effects of stenting on wide-necked intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-sen; LUO Bin; LI Chuan-hui; YANG Xin-jian; WANG Sheng-zhang; QIAO Ai-ke; CHEN Jia-liang; ZHANG Kun-ya; LIU Zhi-cheng; ZHAO Yu-jing; ZHANG Ying

    2010-01-01

    Background Stent placement has been widely used to assist coiling in cerebral aneurysm treatments. The present study aimed to investigate the hemodynamic effects of stenting on wide-necked intracranial aneurysms.Methods Three idealized plexiglass aneudsmal models with different geometries before and after stenting were created, and their three-dimensional computational models were constructed. Flow dynamics in stented and unstented aneurismal models were studied using in vitro flow visualization and computational fluid dynamics (CFD) simulations. In addition, effects of stenting on flow dynamics in a patient-specific aneurysm model were also analyzed by CFD.Results The results of flow visualization were consistent with those obtained with CFD simulations. Stent deployment reduced vortex inside the aneurysm and its impact on the aneurysm sac, and decreased wall shear stress on the sac.Different aneurysm geometries dictated fundamentally different hemodynamic patterns and outcomes of stenting.Conclusions Stenting across the neck of aneurysms improves local blood flow profiles. This may facilitate thrombus formation in aneurysms and decrease the chance of recanalization.

  4. Hemodynamic aspects of normal human feto-placental (umbilical) circulation.

    Science.gov (United States)

    Acharya, Ganesh; Sonesson, Sven-Erik; Flo, Kari; Räsänen, Juha; Odibo, Anthony

    2016-06-01

    Understanding the changes in normal circulatory dynamics that occur during the course of pregnancy is essential for improving our knowledge of pathophysiological mechanisms associated with feto-placental diseases. The umbilical circulation is the lifeline of the fetus, and it is accessible for noninvasive assessment. However, not all hemodynamic parameters can be reliably measured in utero using currently available technology. Experimental animal studies have been crucial in validating major concepts related to feto-placental circulatory physiology, but caution is required in directly translating the findings of such studies into humans due to species differences. Furthermore, it is important to establish normal reference ranges and take into account gestational age associated changes while interpreting the results of clinical investigation. Therefore, it is necessary to critically evaluate, synthesize and summarize the knowledge available from the studies performed on human pregnancies to be able to appropriately apply them in clinical practice. This narrative review is an attempt to present contemporary concepts on hemodynamics of feto-placental circulation based on human studies. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

  5. Antiangiogenic factors and maternal hemodynamics during intensive hemodialysis in pregnancy.

    Science.gov (United States)

    Cornelis, Tom; Spaanderman, Marc; Beerenhout, Charles; Perschel, Frank H; Verlohren, Stefan; Schalkwijk, Casper G; van der Sande, Frank M; Kooman, Jeroen P; Hladunewich, Michelle

    2013-10-01

    We report on a 21-year-old pregnant patient with IgA nephropathy who was initiated on intensive hemodialysis (8 hours of hemodialysis 3 times a week) at a gestational age of 26 weeks on the basis of worsening kidney function resulting in rapidly progressive fatigue and difficulties in metabolic control. Throughout the pregnancy, and while on intensive hemodialysis, 24-hour ambulatory blood pressure control was within the target, and results of weekly 24-hour measurement of central hemodynamics and pulse wave velocity, and of serial levels of circulating (anti-)angiogenic factors were comparable to normal pregnancies. Estimated fetal growth evolved along the 50th percentile, and no polyhydramnios was detected. After induction for a sudden, unexplained increase in blood pressure, she delivered a healthy boy of 2480 g at a gestational age of 36 weeks. This case adds to the expanding literature that supports the use of intensive hemodialysis in pregnant patients with end-stage renal disease and illustrates, for the first time, the potential use of serial (anti-) angiogenic factors and 24-hour measurements of blood pressure and hemodynamic indices in order to facilitate monitoring of these complicated patients.

  6. Computational Hemodynamic Simulation of Human Circulatory System under Altered Gravity

    Science.gov (United States)

    Kim. Chang Sung; Kiris, Cetin; Kwak, Dochan

    2003-01-01

    A computational hemodynamics approach is presented to simulate the blood flow through the human circulatory system under altered gravity conditions. Numerical techniques relevant to hemodynamics issues are introduced to non-Newtonian modeling for flow characteristics governed by red blood cells, distensible wall motion due to the heart pulse, and capillary bed modeling for outflow boundary conditions. Gravitational body force terms are added to the Navier-Stokes equations to study the effects of gravity on internal flows. Six-type gravity benchmark problems are originally presented to provide the fundamental understanding of gravitational effects on the human circulatory system. For code validation, computed results are compared with steady and unsteady experimental data for non-Newtonian flows in a carotid bifurcation model and a curved circular tube, respectively. This computational approach is then applied to the blood circulation in the human brain as a target problem. A three-dimensional, idealized Circle of Willis configuration is developed with minor arteries truncated based on anatomical data. Demonstrated is not only the mechanism of the collateral circulation but also the effects of gravity on the distensible wall motion and resultant flow patterns.

  7. Methylene blue as a cerebral metabolic and hemodynamic enhancer.

    Directory of Open Access Journals (Sweden)

    Ai-Ling Lin

    Full Text Available By restoring mitochondrial function, methylene blue (MB is an effective neuroprotectant in many neurological disorders (e.g., Parkinson's and Alzheimer's diseases. MB has also been proposed as a brain metabolic enhancer because of its action on mitochondrial cytochrome c oxidase. We used in vitro and in vivo approaches to determine how MB affects brain metabolism and hemodynamics. For in vitro, we evaluated the effect of MB on brain mitochondrial function, oxygen consumption, and glucose uptake. For in vivo, we applied neuroimaging and intravenous measurements to determine MB's effect on glucose uptake, cerebral blood flow (CBF, and cerebral metabolic rate of oxygen (CMRO(2 under normoxic and hypoxic conditions in rats. MB significantly increases mitochondrial complex I-III activity in isolated mitochondria and enhances oxygen consumption and glucose uptake in HT-22 cells. Using positron emission tomography and magnetic resonance imaging (MRI, we observed significant increases in brain glucose uptake, CBF, and CMRO(2 under both normoxic and hypoxic conditions. Further, MRI revealed that MB dramatically increased CBF in the hippocampus and in the cingulate, motor, and frontoparietal cortices, areas of the brain affected by Alzheimer's and Parkinson's diseases. Our results suggest that MB can enhance brain metabolism and hemodynamics, and multimetric neuroimaging systems offer a noninvasive, nondestructive way to evaluate treatment efficacy.

  8. Bicuspid aortic valve hemodynamics: a fluid-structure interaction study

    Science.gov (United States)

    Chandra, Santanu; Seaman, Clara; Sucosky, Philippe

    2011-11-01

    The bicuspid aortic valve (BAV) is a congenital defect in which the aortic valve forms with two leaflets instead of three. While calcific aortic valve disease (CAVD) also develops in the normal tricuspid aortic valve (TAV), its progression in the BAV is more rapid. Although studies have suggested a mechano-potential root for the disease, the native BAV hemodynamics remains largely unknown. This study aimed at characterizing BAV hemodynamics and quantifying the degree of wall-shear stress (WSS) abnormality on BAV leaflets. Fluid-structure interaction models validated with particle-image velocimetry were designed to predict the flow and leaflet dynamics in idealized TAV and BAV anatomies. Valvular function was quantified in terms of the effective orifice area. The regional leaflet WSS was characterized in terms of oscillatory shear index, temporal shear magnitude and temporal shear gradient. The predictions indicate the intrinsic degree of stenosis of the BAV anatomy, reveal drastic differences in shear stress magnitude and pulsatility on BAV and TAV leaflets and confirm the side- and site-specificity of the leaflet WSS. Given the ability of abnormal fluid shear stress to trigger valvular inflammation, these results support the existence of a mechano-etiology of CAVD in the BAV.

  9. Assessment of turbulent viscous stress using ICOSA 4D Flow MRI for prediction of hemodynamic blood damage

    Science.gov (United States)

    Ha, Hojin; Lantz, Jonas; Haraldsson, Henrik; Casas, Belen; Ziegler, Magnus; Karlsson, Matts; Saloner, David; Dyverfeldt, Petter; Ebbers, Tino

    2016-12-01

    Flow-induced blood damage plays an important role in determining the hemodynamic impact of abnormal blood flow, but quantifying of these effects, which are dominated by shear stresses in highly fluctuating turbulent flow, has not been feasible. This study evaluated the novel application of turbulence tensor measurements using simulated 4D Flow MRI data with six-directional velocity encoding for assessing hemodynamic stresses and corresponding blood damage index (BDI) in stenotic turbulent blood flow. The results showed that 4D Flow MRI underestimates the maximum principal shear stress of laminar viscous stress (PLVS), and overestimates the maximum principal shear stress of Reynolds stress (PRSS) with increasing voxel size. PLVS and PRSS were also overestimated by about 1.2 and 4.6 times at medium signal to noise ratio (SNR) = 20. In contrast, the square sum of the turbulent viscous shear stress (TVSS), which is used for blood damage index (BDI) estimation, was not severely affected by SNR and voxel size. The square sum of TVSS and the BDI at SNR >20 were underestimated by less than 1% and 10%, respectively. In conclusion, this study demonstrated the feasibility of 4D Flow MRI based quantification of TVSS and BDI which are closely linked to blood damage.

  10. Hemodynamic effects of combined focal cerebral ischemia and amyloid protein toxicity in a rat model: a functional CT study.

    Directory of Open Access Journals (Sweden)

    Jun Yang

    Full Text Available BACKGROUND/OBJECTIVE: Clinical evidence indicates that cerebral ischemia (CI and a pathological factor of Alzheimer's disease, the β-amyloid (Aβ protein, can increase the rate of cognitive impairment in the ageing population. Using the CT Perfusion (CTP functional imaging, we sought to investigate the interaction between CI and the Aβ protein on cerebral hemodynamics. METHODS: A previously established rat model of CI and Aβ was used for the CTP study. Iodinated contrast was given intravenously, while serial CT images of sixteen axial slices were acquired. Cerebral blood flow (CBF and blood volume (CBV parametric maps were co-registered to a rat brain atlas and regions of interest were drawn on the maps. Microvascular alteration was investigated with histopathology. RESULTS: CTP results revealed that ipsilateral striatum of Aβ+CI and CI groups showed significantly lower CBF and CBV than control at the acute phase. Striatal CBF and CBV increased significantly at week 1 in the CI and Aβ+CI groups, but not in the Aβ alone or control group. Histopathology showed that average density of dilated microvessels in the ipsilateral striatum in CI and Aβ+CI groups was significantly higher than control at week 1, indicating this could be associated with hyperperfusion and hypervolemia observed from CTP results. CONCLUSION: These results demonstrate that CTP can quantitatively measure the hemodynamic disturbance on CBF and CBV functional maps in a rat model of CI interacting with Aβ.

  11. (-)-Epigallocatechin-3-O-gallate (EGCG) attenuates the hemodynamics stimulated by caffeine through decrease of catecholamines release.

    Science.gov (United States)

    Han, Jin-Yi; Moon, Yong-Jin; Han, Jong-Hyun; Kim, Jong-Hoon; Woo, Jae-Hoon; Yoo, Hwan-Soo; Hong, Jin Tae; Ahn, Hee-Yul; Hong, Jong-Myeon; Oh, Ki-Wan

    2016-09-01

    A human study of the effects on hemodynamics of caffeine and epigallocatechin-3-O-gallate (EGCG) was performed. Caffeine tablets (200 mg) were orally administered to healthy males aged between 25 and 35 years 30 min after oral administration of EGCG tablets (100 and 200 mg). The increase in BP induced by caffeine was inhibited when co-administrated with EGCG. We found that caffeine slightly decreased heart rate (HR) in the volunteers. Although EGCG enhanced HR reduction, the effect was not significant. In addition, caffeine increased blood catecholamine levels, but EGCG inhibited the increase in noradrenaline, adrenaline and dopamine levels induced by caffeine. Whether EGCG decreases the elevated HR and systolic perfusion pressure, and ventricular contractility induced by adrenergic agonists in the isolated rat heart was investigated. The modified Krebs-Henseleit solution was perfused through a Langendorff apparatus to the isolated hearts of rats. HR, systolic perfusion pressure, and developed maximal rates of contraction (+dP/dtmax) and relaxation (-dP/dtmax) were increased by epinephrine (EP) and isoproterenol (IP). In contrast, EGCG decreased the elevated HR, systolic perfusion pressure, and left ventricular ±dp/dtmax induced by EP and/or IP. In conclusion, EGCG could attenuate the hemodynamics stimulated by caffeine through decreasing catecholamine release.

  12. Chronic monitoring of cortical hemodynamics in behaving, freely-moving rats using a miniaturized head-mounted optical microscope

    Science.gov (United States)

    Sigal, Iliya; Gad, Raanan; Koletar, Margaret; Ringuette, Dene; Stefanovic, Bojana; Levi, Ofer

    2016-03-01

    Growing interest within the neurophysiology community in assessing healthy and pathological brain activity in animals that are awake and freely-behaving has triggered the need for optical systems that are suitable for such longitudinal studies. In this work we report label-free multi-modal imaging of cortical hemodynamics in the somatosensory cortex of awake, freely-behaving rats, using a novel head-mounted miniature optical microscope. The microscope employs vertical cavity surface emitting lasers (VCSELs) at three distinct wavelengths (680 nm, 795 nm, and 850 nm) to provide measurements of four hemodynamic markers: blood flow speeds, HbO, HbR, and total Hb concentration, across a > 2 mm field of view. Blood flow speeds are extracted using Laser Speckle Contrast Imaging (LSCI), while oxygenation measurements are performed using Intrinsic Optical Signal Imaging (IOSI). Longitudinal measurements on the same animal are made possible over the course of > 6 weeks using a chronic window that is surgically implanted into the skull. We use the device to examine changes in blood flow and blood oxygenation in superficial cortical blood vessels and tissue in response to drug-induced absence-like seizures, correlating motor behavior with changes in blood flow and blood oxygenation in the brain.

  13. Prefrontal hemodynamic mapping by functional near-infrared spectroscopy in response to thermal stimulations over three body sites.

    Science.gov (United States)

    Yennu, Amarnath; Tian, Fenghua; Gatchel, Robert J; Liu, Hanli

    2016-10-01

    Functional near-infrared spectroscopy (fNIRS) was used to examine hemodynamic responses in the prefrontal cortex (PFC) during noxious thermal pain, induced by thermal stimulations over three different body sites over the right forearm, right temporomandibular joint, and left forearm. Functional NIRS measurements were obtained from three groups of healthy volunteers, one group for each body region. Each group was subjected to both low-pain stimulation (LPS) and high-pain stimulation (HPS) by a [Formula: see text] thermode of a temperature-controlled thermal stimulator over the respective three body sites. Our results showed that HPS given at three sites induced significant increases ([Formula: see text]) in oxy-hemoglobin concentration ([Formula: see text]) in the PFC with similar temporal patterns in relatively spread PFC areas. In contrast, LPS did not cause any significant [Formula: see text] in the PFC of any subject group. Our observed PFC activations induced by acute HPS were generally consistent with previous reports by fMRI studies. The study also found a peculiar global trend of postpain deactivation in the PFC, which is attributed to global vasoconstriction due to acute nocuous pain. Overall, these results indicate that hemodynamic activities in PFC exhibit consistent temporal and spatial patterns in response to acute thermal stimulation given across all three body sites.

  14. Hemodynamic segmentation of brain perfusion images with delay and dispersion effects using an expectation-maximization algorithm.

    Directory of Open Access Journals (Sweden)

    Chia-Feng Lu

    Full Text Available Automatic identification of various perfusion compartments from dynamic susceptibility contrast magnetic resonance brain images can assist in clinical diagnosis and treatment of cerebrovascular diseases. The principle of segmentation methods was based on the clustering of bolus transit-time profiles to discern areas of different tissues. However, the cerebrovascular diseases may result in a delayed and dispersed local perfusion and therefore alter the hemodynamic signal profiles. Assessing the accuracy of the segmentation technique under delayed/dispersed circumstance is critical to accurately evaluate the severity of the vascular disease. In this study, we improved the segmentation method of expectation-maximization algorithm by using the results of hierarchical clustering on whitened perfusion data as initial parameters for a mixture of multivariate Gaussians model. In addition, Monte Carlo simulations were conducted to evaluate the performance of proposed method under different levels of delay, dispersion, and noise of signal profiles in tissue segmentation. The proposed method was used to classify brain tissue types using perfusion data from five normal participants, a patient with unilateral stenosis of the internal carotid artery, and a patient with moyamoya disease. Our results showed that the normal, delayed or dispersed hemodynamics can be well differentiated for patients, and therefore the local arterial input function for impaired tissues can be recognized to minimize the error when estimating the cerebral blood flow. Furthermore, the tissue in the risk of infarct and the tissue with or without the complementary blood supply from the communicating arteries can be identified.

  15. Invasive and non-invasive fractional flow reserve index in validation of hemodynamic severity of intracoronary lesions.

    Science.gov (United States)

    Wasilewski, Jarosław; Mirota, Kryspin; Hawranek, Michał; Poloński, Lech

    2013-01-01

    This review discusses visual and functional evaluation of the hemodynamic significance of the degree of stenosis in coronary angiography, with respect to the indications for revascularization. The concept of the coronary flow reserve is defined, and the theoretical assumptions of the invasive measurement of the fractional flow reserve (FFR) are presented. In the following part, the publication describes the basic steps of numerical stimulations in terms of computational fluid dynamics (CFD) in calculating the fractional flow reserve based on computed tomography (CT) coronary angiography (FFRCT). The numerical FFRCT estimation in correlation with invasive measurements, as well as benefits deriving from FFRCT in the diagnosis of coronary artery disease, is presented in the example of the multicentre prospective DISCOVER-FLOW trial and the DeFACTO project. The CDF method enables to obtain hemodynamic significance of stenosis solely from the coronary anatomy vizualized by CT angiography. The calculation of FFRCT increases the diagnostic reliability of coronary flow reserve estimations. It contributes to the improvement in patients' qualification for contrast coronarography. If the accuracy of FFRCT is confirmed in clinical practice, and the time required for computational processing is shortened, it may turn out that the algorithms of coronary heart disease diagnosis will be verified and it will be to a greater extent based on the CT results.

  16. Anisotropic contrast optical microscope

    Science.gov (United States)

    Peev, D.; Hofmann, T.; Kananizadeh, N.; Beeram, S.; Rodriguez, E.; Wimer, S.; Rodenhausen, K. B.; Herzinger, C. M.; Kasputis, T.; Pfaunmiller, E.; Nguyen, A.; Korlacki, R.; Pannier, A.; Li, Y.; Schubert, E.; Hage, D.; Schubert, M.

    2016-11-01

    An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm2 object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves

  17. Effect of tilting on cerebral hemodynamics in preterm and term infants

    NARCIS (Netherlands)

    Pichler, G; van Boetzelar, MC; Muller, W; Urlesberger, B

    2001-01-01

    Tilting is known to cause changes in hemodynamics due to hydrostatic pressure. The present study is an analysis of changes in cerebral hemodynamics measured by near infrared spectroscopy (NIRS) following tilting up and down in preterm and term infants. A significantly different effect of tilting up

  18. Use of lignocaine or nitroglycerine for blunting of hemodynamic stress response during electroconvulsive therapy

    Directory of Open Access Journals (Sweden)

    Muhammad Umar Zahoor

    2014-01-01

    Conclusion: NTG provided more hemodynamic stability in post-ECT period as compared to lignocaine which only prevented a surge in HR without any effect on MAP. We conclude that NTG can safely be instituted for anaesthesia in ECT patients for prevention of hemodynamic stress response.

  19. Encephalic hemodynamic phases in subarachnoid hemorrhage:how to improve the protective effect in patient prognoses

    Institute of Scientific and Technical Information of China (English)

    Marcelo de Lima Oliveira; Daniel Silva de Azevedo; Milena Krajnyk de Azevedo; Ricardo de Carvalho Nogueira; Manoel Jacobsen Teixeira; Edson Bor-Seng-Shu

    2015-01-01

    Subarachnoid hemorrhage is frequently associated with poor prognoses. Three different hemo-dynamic phases were identified during subarachnoid hemorrhage: oligemia, hyperemia, and vasospasm. Each phase is associated with brain metabolic changes. In this review, we correlated the hemodynamic phases with brain metabolism and potential treatment options in the hopes of improving patient prognoses.

  20. Effects of tilting on central hemodynamics and homeostatic mechanisms in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Nørgaard, Annette; Henriksen, Jens H

    2004-01-01

    in the supine patient, we studied the humoral and central hemodynamic responses to changes with posture. Twenty-three patients with alcoholic cirrhosis (Child-Turcotte-Pugh classes A/B/C: 2/13/8) and 14 healthy controls were entered. Measurements of central hemodynamics and activation of SNS and RAAS were taken...

  1. Prognostic value of renal hemodynamic characteristics in patients with proliferative lupus nephritis

    NARCIS (Netherlands)

    Martens, Henk A.; Bijl, Marc; Kallenberg, Cees G. M.

    2007-01-01

    Background/Aim: Previous studies showed that renal hemodynamic parameters, especially the filtration fraction ( FF), are decreased in patients with active lupus nephritis ( LN). In this study, we evaluate the prognostic value of renal hemodynamic function tests on the renal outcome in patients with

  2. Staging of hemodynamic parameters during development of experimental arterial hypertension in rabbits.

    Science.gov (United States)

    Frolov, V A; Blagonravov, M L; Zotov, A K; Zotova, T J

    2011-05-01

    The study analyzed changes in parameters of the central and intracardiac hemodynamics during the development of experimental arterial hypertension, which were assessed as the adaptive in nature. The development of hypertension demonstrated staging of the adaptive processes. The development of the adaptive responses was characterized by changes in the magnitude and probabilistic distribution of the hemodynamic parameters.

  3. Encephalic hemodynamic phases in subarachnoid hemorrhage: how to improve the protective effect in patient prognoses

    Directory of Open Access Journals (Sweden)

    Marcelo de Lima Oliveira

    2015-01-01

    Full Text Available Subarachnoid hemorrhage is frequently associated with poor prognoses. Three different hemodynamic phases were identified during subarachnoid hemorrhage: oligemia, hyperemia, and vasospasm. Each phase is associated with brain metabolic changes. In this review, we correlated the hemodynamic phases with brain metabolism and potential treatment options in the hopes of improving patient prognoses.

  4. Hemodynamic Monitoring Devices Market: Prominent Driver are Burgeoning prevalence of lifestyle disorders and cardiac diseases

    OpenAIRE

    Smita Deshmukh

    2016-01-01

    Transparency Market Research Reports incorporated a definite business overview and investigation inclines on "Hemodynamic Monitoring Devices Market". This report likewise incorporates more illumination about fundamental review of the business including definitions, requisitions and worldwide business sector industry structure.   Read Full Report: http://www.transparencymarketresearch.com/hemodynamic-monitoring-devices-market.html

  5. Year in review in journal of clinical monitoring and computing 2014 : cardiovascular and hemodynamic monitoring

    NARCIS (Netherlands)

    Bendjelid, Karim; Rex, Steffen; Scheeren, Thomas; Critchley, Lester

    Hemodynamic instability is a common sign in critically ill patients and its importance has been increasingly recognized during the last 20 years. Indeed, It is now appreciated that an adequate hemodynamic monitoring associated to reactive vigorous therapy is able to decrease the present ominous

  6. Acute effects of power and resistance exercises on hemodynamic measurements of older women

    Directory of Open Access Journals (Sweden)

    Coelho-Júnior HJ

    2017-07-01

    Full Text Available Hélio José Coelho-Júnior,1,2 Maria-Cláudia Irigoyen,3 Samuel da Silva Aguiar,2,4 Ivan de Oliveira Gonçalves,2,5 Niels Olsen Saraiva Câmara,6 Marco Antonio Cenedeze,7 Ricardo Yukio Asano,2,8 Bruno Rodrigues,1 Marco Carlos Uchida1 1Applied Kinesiology Laboratory–LCA, School of Physical Education, University of Campinas, Barão Geraldo, Campinas, São Paulo, 2Center of Health Sciences, University of Mogi das Cruzes, Mogi das Cruzes, 3Hypertension Unit, Heart Institute (InCor, Medical School of University of São Paulo, 4School of Physical Education, Catholic University of Brasília, Águas Claras, Brasília, 5Community Center for Older People of Poá, Poá, 6Department of Immunobiology, Laboratory of Transplantation Immunology, Institute of Biomedical Sciences, University of São Paulo, 7Nephrology Division, Federal University of São Paulo, 8School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil Purpose: The purpose of this study was to compare the acute effects of resistance training (RT and power training (PT on the hemodynamic parameters and nitric oxide (NO bioavailability of older women. Materials and methods: A randomized experimental design was used in this study. Twenty-one older women (age: 67.1±4.6 years; body mass index: 28.03±4.9 kg/m2; systolic blood pressure: 135.1±21.1 mmHg were recruited to participate in this study. Volunteers were randomly allocated into PT, RT, and control session (CS groups. The PT and RT groups underwent a single session of physical exercise equalized by training volume, characterized by 3 sets of 8–10 repetitions in 8 different exercises. However, RT group performed exercise at a higher intensity (difficult than PT (moderate group. On the other hand, concentric contractions were faster in PT group than in RT group. Hemodynamic parameters and saliva samples (for NO quantification were collected before and during an hour after exercise completion. Results: Results

  7. Adverse reactions following administration of an ionic iodinated contrast media in anesthetized dogs.

    Science.gov (United States)

    Vance, Amanda; Nelson, Matthew; Hofmeister, Erik H

    2012-01-01

    This retrospective study was conducted to identify hemodynamic alterations associated with the administration of an ionic iodinated contrast media in dogs. Case records of 49 dogs that were anesthetized for computed tomography scanning were reviewed. Values for heart rate (HR) and direct arterial pressure were obtained. Overall, 37% of dogs had a ≥20% change in either HR or systolic arterial pressure from baseline values. Four dogs (8%) became tachycardic and two dogs (4%) became bradycardic. Eight dogs (16%) became hypertensive and two dogs (4%) became hypotensive. A significant proportion of dogs experienced changes in HR and blood pressure following IV administration of an ionic iodinated contrast media under general anesthesia.

  8. The Comparisons of Cerebral Hemodynamics Induced by Obstructive Sleep Apnea with Arousal and Periodic Limb Movement with Arousal: A Pilot NIRS Study

    Science.gov (United States)

    Zhang, Zhongxing; Schneider, Maja; Laures, Marco; Qi, Ming; Khatami, Ramin

    2016-01-01

    Obstructive sleep apnea syndrome (OSA) and restless legs syndrome (RLS) with periodic limb movement during sleep (PLMS) are two sleep disorders characterized by repetitive respiratory or movement events associated with cortical arousals. We compared the cerebral hemodynamic changes linked to periodic apneas/hypopneas with arousals (AHA) in four OSA-patients with periodic limb movements (PLMA) with arousals in four patients with RLS-PLMS using near-infrared spectroscopy (NIRS). AHA induced homogenous pattern of periodic fluctuations in oxygenated (HbO2) and deoxygenated (HHb) hemoglobin, i.e., the decrease of HbO2 was accompanied by an increase of HHb during the respiratory event and resolved to reverse pattern when cortical arousal started. Blood volume (BV) showed the same pattern as HHb but with relative smaller amplitude in most of the AHA events.These changing patterns were significant as Wilcoxon signed-rank tests gave p < 0.001 when comparing the area under the curve of these hemodynamic parameters to zero. By contrast, in PLMA limb movements induced periodic increments in HbO2 and BV (Wilcoxon signed-rank tests, p < 0.001), but HHb changed more heterogeneously even during the events coming from the same patient. Heart rate (HR) also showed different patterns between AHA and PLMA. It significantly decreased during the respiratory event (Wilcoxon signed-rank test, p < 0.001) and then increased after the occurrence of cortical arousal (Wilcoxon signed-rank test, p < 0.001); while in PLMA HR first increased preceding the occurrence of cortical arousal (Wilcoxon signed-rank test, p < 0.001) and then decreased. The results of this preliminary study show that both AHA and PLMA induce changes in cerebral hemodynamics. The occurrence of cortical arousal is accompanied by increased HR in both events, but by different BV changes (i.e., decreased/increased BV in AHA/PLMA, respectively). HR changes may partially account for the increased cerebral hemodynamics during PLMA

  9. Hemodynamic response to treatment of iron deficiency anemia in pulmonary arterial hypertension: longitudinal insights from an implantable hemodynamic monitor.

    Science.gov (United States)

    Mehmood, Muddassir; Agarwal, Richa; Raina, Amresh; Correa-Jaque, Priscilla; Benza, Raymond L

    2016-12-01

    Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) were measured on a daily basis, and parameters of right ventricular (RV) performance and afterload were calculated. At the time of IHM implant, the patient had functional class III symptoms, was receiving triple-drug therapy, and had normal hemoglobin levels. Four months after implant, and with further optimization of prostacyclin therapy, she had improvement in her symptoms. However, shortly thereafter, while the patient was receiving stable drug therapy, her case regressed with worsening symptoms, and the patient received a new diagnosis of iron deficiency anemia. Oral iron supplementation resulted in normalization of hemoglobin levels and improvement in the patient's iron profile. A gradual and sustained reduction in pulmonary pressures was noted after initiation of oral iron accompanied by increased RV performance and favorable reduction in RV afterload. The patient had significant symptomatic improvement. Iron deficiency is an underappreciated yet easily treatable risk factor in PAH. Use of IHM in this case longitudinally illustrates the optimization of pulmonary hemodynamics and RV afterload in tandem with clinical improvement achieved by a simple therapy.

  10. Hemodynamic response to treatment of iron deficiency anemia in pulmonary arterial hypertension: longitudinal insights from an implantable hemodynamic monitor

    Science.gov (United States)

    2016-01-01

    Abstract Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) were measured on a daily basis, and parameters of right ventricular (RV) performance and afterload were calculated. At the time of IHM implant, the patient had functional class III symptoms, was receiving triple-drug therapy, and had normal hemoglobin levels. Four months after implant, and with further optimization of prostacyclin therapy, she had improvement in her symptoms. However, shortly thereafter, while the patient was receiving stable drug therapy, her case regressed with worsening symptoms, and the patient received a new diagnosis of iron deficiency anemia. Oral iron supplementation resulted in normalization of hemoglobin levels and improvement in the patient’s iron profile. A gradual and sustained reduction in pulmonary pressures was noted after initiation of oral iron accompanied by increased RV performance and favorable reduction in RV afterload. The patient had significant symptomatic improvement. Iron deficiency is an underappreciated yet easily treatable risk factor in PAH. Use of IHM in this case longitudinally illustrates the optimization of pulmonary hemodynamics and RV afterload in tandem with clinical improvement achieved by a simple therapy. PMID:28090307

  11. High Contrast CRT.

    Science.gov (United States)

    1979-08-01

    r AD’ A076 235 WATKINS—JOHNSON Co SCOTYS VAL LEY CA F/S 9/5 N HIGH CONTRAST CRT.CU) AUG 79 6 A HOLNQUIST DAABO7—77—C—263 9 UNCLASSIFIED DEL.ET—TR—77...Air Force Systems Command A t t n : l) l . CA 2w) U I f iee ’ of \\ iva l Re ’~.ea r ch Andr ews AFI4 ( • ~~ii 4.~7 001 Washington , l ) .C. 20331

  12. Changes in cerebral and ocular hemodynamics in Behcet's disease assessed by color-coded duplex sonography

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    Yilmaz, Sevda [Department of Radiology, School of Medicine, University of Kirikkale, Kirikkale (Turkey)]. E-mail: dryilmazsevda@yahoo.com; Akarsu, Cengiz [Department of Ophthalmology, School of Medicine, University of Kirikkale, Kirikkale (Turkey)

    2006-04-15

    Aim: To quantify the cerebral and retrobulbar hemodynamics in Behcet's disease with and without ocular involvement and compared with that of healthy controls. Materials and methods: Of 51 people studied, 17 had Behcet's disease with ocular involvement, 17 had Behcet's disease without ocular involvement, and 17 were healthy controls. A single eye was examined in each patient. Peak systolic velocity (PSV), end-diastolic velocity (EDV), time-averaged maximum velocity (Tamax), and resistance index (RI) were evaluated in the ophthalmic (OA), posterior ciliary (PCA), central retinal (CRA) and middle cerebral artery (MCA). Additionally, the average blood flow velocities in the central retinal vein (CRV), and acceleration time (AT) and pulsatility index (PI) in the MCA were calculated. Results: The mean EDV in the PCA was 25% lower and RI was higher in patients with ocular involvement of BD than in patients without involvement (p = 0.006 and p = 0.005, respectively) and in healthy controls (p = 0.003 and p = 0.004, respectively). Differences were smaller in comparisons of the CRA and absent on comparisons of the OA and MCA. The acceleration time of the MCA was significantly higher in patients with Behcet's disease than in healthy controls (p = 0.03). Conclusion: This study suggests that the flow hemodynamics in retrobulbar circulation has more altered Behcet's disease with ocular involvement than without ocular involvement and healthy control. Additionally, the cerebral hemodynamic might be affected in patients with Behcet's disease compared with healthy controls.

  13. A comparison of hemodynamic effects of levosimendan and dobutamine in patients undergoing mitral valve repair / replacement for severe mitral stenosis

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    Ravikumar Gandham

    2013-01-01

    Full Text Available Aims and Objectives: We aimed to compare the hemodynamic effects of levosimendan and dobutamine in patients undergoing mitral valve surgery on cardiopulmonary bypass (CPB. Materials and Methods: Sixty patients were divided into 2 groups of 30 each. Group-L patients received levosimendan 0.1 μg/kg/min and Group-D patients received dobutamine 5 μg/kg/min while weaning off CPB. Additional inotrope and/or vasoconstrictor were started based on hemodynamic parameters. Hemodynamic data were collected at the end and at 30 minutes after CPB, thereafter at 6, 12, 24, and 36 hours post-CPB. Mean arterial pressure (MAP, central venous pressure (CVP, heart rate (HR, cardiac index (CI, systemic vascular resistance index (SVRI, and lactate levels were measured. Results: Group-L showed increased requirement of inotropes and vasoconstrictors. The SVRI, CVP, and MAP were reduced more in Group-L. The CI was low in Group-L in the initial period when compared to Group-D. Later Group-L patients showed a statistically significant increase in CI even after 12 hrs of discontinuation of levosimendan infusion. The HR was increased more in Group-D. Lactate levels, intensive care unit stay, and duration of ventilation were similar in both groups. Conclusions: Levosimendan 0.1 μg/kg/min compared to dobutamine 5 μg/kg/min showed more vasodilation and lesser inotropic activity in patients undergoing mitral valve surgery for mitral stenosis. Levosimendan compared to dobutamine showed a statistically significant increase in CI even after 12 hrs of discontinuation. The requirement of another inotrope or vasopressor was frequent in levosimendan group.

  14. Comparison of hemodynamic and metabolic stress responses caused by endotracheal tube and Proseal laryngeal mask airway in laparoscopic cholecystectomy

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    Handan Güleç

    2012-01-01

    Full Text Available Background: We aimed to compare hemodynamic and endocrine alterations caused by stress response due to Proseal laryngeal mask airway and endotracheal tube usage in laparoscopic cholecystectomy. Materials and Methods: Sixty-three ASA I-II patients scheduled for elective laparoscopic cholecystectomy were included in the study. Patients were randomly allocated into two groups of endotracheal tube and Proseal laryngeal mask airway. Standard general anaesthesia was performed in both groups with the same drugs in induction and maintenance of anaesthesia. After anaesthesia induction and 20 minutes after CO 2 insufflations, venous blood samples were obtained for measuring adrenalin, noradrenalin, dopamine and cortisol levels. Hemodynamic and respiratory parameters were recorded at the 1 st , 5 th , 15 th , 30 th and 45 th minutes after the insertion of airway devices. Results: No statistically significant differences in age, body mass index, gender, ASA physical status, and operation time were found between the groups (p > 0.05. Changes in hemodynamic and respiratory parameters were not statistically significant when compared between and within groups (p > 0.05. Although no statistically significant differences were observed between and within groups when adrenalin, noradrenalin and dopamine values were compared, serum cortisol levels after CO 2 insufflation in PLMA group were significantly lower than the ETT group (p = 0.024. When serum cortisol levels were compared within groups, cortisol levels 20 minutes after CO 2 insufflation were significantly higher (46.1 (9.5-175.7 and 27.0 (8.3-119.4 in the ETT and PLMA groups, respectively than cortisol levels after anaesthesia induction (11.3 (2.8-92.5 and 16.6 (4.4-45.4 in the ETT and PLMA groups, respectively in both groups (p = 0.001. Conclusion: PLMA usage is a suitable, effective and safe alternative to ETT in laparoscopic cholecystectomy patients with lower metabolic stress.

  15. Re-examine tumor-induced alterations in hemodynamic responses of BOLD fMRI. Implications in presurgical brain mapping

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    Wang, Liya [Dept. of Radiology and Imaging Sciences, Emory Univ., School of Medicine, Atlanta (United States); Dept. of Radiology, Baoan Hospital, Shenzhen (China); Ali, Shazia; Fa, Tianning; Mao, Hui [Dept. of Radiology and Imaging Sciences, Emory Univ., School of Medicine, Atlanta (United States)], e-mail: hmao@emory.edu; Dandan, Chen [Dept. of Physics, Emory Univ., Atlanta, (United States); School of Radiation Medicine and Protection, Soochow Univ., Suzhou (China); Olson, Jeffrey [Dept. of Neurosurgery, Emory Univ., School of Medicine, Atlanta (United States)

    2012-09-15

    Background: Blood oxygenation level dependent (BOLD) fMRI is used for presurgical functional mapping of brain tumor patients. Abnormal tumor blood supply may affect hemodynamic responses and BOLD fMRI signals. Purpose: To perform a multivariate and quantitative investigation of the effect of brain tumors on the hemodynamic responses and its impact on BOLD MRI signal time course, data analysis in order to better understand tumor-induced alterations in hemodynamic responses, and accurately mapping cortical regions in brain tumor patients. Material and Methods: BOLD fMRI data from 42 glioma patients who underwent presurgical mapping of the primary motor cortex (PMC) with a block designed finger tapping paradigm were analyzed, retrospectively. Cases were divided into high grade (n = 24) and low grade (n = 18) groups based on pathology. The tumor volume and distance to the activated PMCs were measured. BOLD signal time courses from selected regions of interest (ROIs) in the PMCs of tumor affected and contralateral unaffected hemispheres were obtained from each patient. Tumor-induced changes of BOLD signal intensity and time to peak (TTP) of BOLD signal time courses were analyzed statistically. Results: The BOLD signal intensity and TTP in the tumor-affected PMCs are altered when compared to that of the unaffected hemisphere. The average BOLD signal level is statistically significant lower in the affected PMCs. The average TTP in the affected PMCs is shorter in the high grade group, but longer in the low grade tumor group compared to the contralateral unaffected hemisphere. Degrees of alterations in BOLD signal time courses are related to both the distance to activated foci and tumor volume with the stronger effect in tumor distance to activated PMC. Conclusion: Alterations in BOLD signal time courses are strongly related to the tumor grade, the tumor volume, and the distance to the activated foci. Such alterations may impair accurate mapping of tumor-affected functional

  16. Effect of naringin on hemodynamic changes and left ventricular function in renal artery occluded renovascular hypertension in rats

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    Asjad Visnagri

    2015-01-01

    Full Text Available Background: Renal artery occlusion (RAO induced hypertension is a major health problem associated with structural and functional variations of the renal and cardiac vasculature. Naringin a flavanone glycoside derived possesses metal-chelating, antioxidant and free radical scavenging properties. Objective: The objective of this study was to investigate the antihypertensive activity of naringin in RAO induced hypertension in rats.Material and Methods: Male Wistar rats (180-200 g were divided into five groups Sham, RAO, naringin (20, 40 and 80 mg/kg. Animals were pretreated with naringin (20, 40 and 80 mg/kg p.o for 4 weeks. On the last day of the experiment, left renal artery was occluded with renal bulldog clamp for 4 h. After assessment of hemodynamic and left ventricular function various biochemical (superoxide dismutase [SOD], glutathione [GSH] and malondialdehyde [MDA] and histological parameters were determined in the kidney. Results: RAO group significantly (P < 0.001 increased hemodynamic parameters at 15, 30 and 45 min of clamp removal. Naringin (40 and 80 mg/kg treated groups showed a significant decrease in hemodynamic parameters at 15 min. after clamp removal that remained sustained for 60 min. Naringin (40 and 80 mg/kg treated groups showed significant improvement in left ventricular function at 15, 30 and 45 min after clamp removal. Alteration in level of SOD, GSH and MDA was significantly restored by naringin (40 and 80 mg/kg treatment. It also reduced histological aberration induced in kidney by RAO. Conclusion: It is concluded that the antihypertensive activity of naringin may result through inhibition of oxidative stress.

  17. Electrophysiological and hemodynamic mismatch responses in rats listening to human speech syllables

    Science.gov (United States)

    Dehaene-Lambertz, Ghislaine; Wallois, Fabrice

    2017-01-01

    Speech is a complex auditory stimulus which is processed according to several time-scales. Whereas consonant discrimination is required to resolve rapid acoustic events, voice perception relies on slower cues. Humans, right from preterm ages, are particularly efficient to encode temporal cues. To compare the capacities of preterms to those observed in other mammals, we tested anesthetized adult rats by using exactly the same paradigm as that used in preterm neonates. We simultaneously recorded neural (using ECoG) and hemodynamic responses (using fNIRS) to series of human speech syllables and investigated the brain response to a change of consonant (ba vs. ga) and to a change of voice (male vs. female). Both methods revealed concordant results, although ECoG measures were more sensitive than fNIRS. Responses to syllables were bilateral, but with marked right-hemispheric lateralization. Responses to voice changes were observed with both methods, while only ECoG was sensitive to consonant changes. These results suggest that rats more effectively processed the speech envelope than fine temporal cues in contrast with human preterm neonates, in whom the opposite effects were observed. Cross-species comparisons constitute a very valuable tool to define the singularities of the human brain and species-specific bias that may help human infants to learn their native language. PMID:28291832

  18. Detecting the Subtle Shape Differences in Hemodynamic Responses at the Group Level

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    Gang eChen

    2015-10-01

    Full Text Available The nature of the hemodynamic response (HDR is still not fully understood due to the multifaceted processes involved. Aside from the overall amplitude, the response may vary across cognitive states, tasks, brain regions, and subjects with respect to characteristics such as rise and fall speed, peak duration, undershoot shape, and overall duration. Here we demonstrate that the fixed-shape or adjusted-shape methods may fail to detect some shape subtleties. In contrast, the estimated-shape method (ESM through multiple basis functions can provide the opportunity to identify some subtle shape differences and achieve higher statistical power at both individual and group levels. Previously, some dimension reduction approaches focused on the peak magnitude, or made inferences based on the area under the curve or interaction, which can lead to potential misidentifications. By adopting a generic framework of multivariate modeling (MVM, we showcase a hybrid approach that is validated by simulations and real data. Unlike the few analyses that were limited to main effect, two- or three-way interactions, we extend the approach to an inclusive platform that is more adaptable than the conventional GLM, achieving a practical equipoise among representation, false positive control, statistical power, and modeling flexibility.

  19. Time-resolved X-ray PIV measurements of hemodynamic information of real pulsatile blood flows

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Lee, Sang Joon

    2015-11-01

    X-ray imaging technique has been used to visualize various bio-fluid flow phenomena as a nondestructive manner. To obtain hemodynamic information related with circulatory vascular diseases, a time-resolved X-ray PIV technique with high temporal resolution was developed. In this study, to embody actual pulsatile blood flows in a circular conduit without changes in hemorheological properties, a bypass loop is established by connecting a microtube between the jugular vein and femoral artery of a rat. Biocompatible CO2 microbubbles are used as tracer particles. After mixing with whole blood, CO2 microbubbles are injected into the bypass loop. Particle images of the pulsatile blood flows in the bypass loop are consecutively captured by the time-resolved X-ray PIV system. The velocity field information are obtained with varying flow rate and pulsataility. To verify the feasibility of the use of CO2 microbubbles under in vivo conditions, the effects of the surrounding-tissues are also investigated, because these effects are crucial for deteriorating the image contrast of CO2 microbubbles. Therefore, the velocity information of blood flows in the abdominal aorta are obtained to demonstrate the visibility and usefulness of CO2 microbubbles under ex vivo conditions. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2008-0061991).

  20. Vaginal hemodynamic changes during sexual arousal in a rat model by diffuse optical spectroscopy (Conference Presentation)

    Science.gov (United States)

    Jeong, Hyeryun; Seong, Myeongsu; Lee, Hyun-Suk; Park, Kwangsung; Kim, Jae Gwan

    2017-02-01

    Not only men suffer from sexual dysfunction, but the number of women who have sexual dysfunction rises. Therefore, it is necessary to develop an objective diagnostic technique to examine the sexual dysfunction of female patients, who are afflicted with the disorders. For this purpose, we developed a diffuse optical spectroscopy (DOS) probe to measure the change of oxy-, deoxy-, and total hemoglobin concentration along with blood flow from vaginal wall of female rats. A cylindrical stainless steel DOS probe with a diameter of 3 mm was designed for the vaginal wall of rats which consisted of two lasers (785 and 850nm) and two spectrometers with a separation of 2 mm. A thermistor was placed on the top of the probe to measure the temperature change from vaginal wall during experiments. A modified Beer-Lambert's law is utilized to acquire the changes of oxy-, deoxy-, and total hemoglobin, and blood flow information is obtained by diffuse speckle contrast analysis technique. For the experiments, Sprague Dawley ( 400 g) female rats were divided into two groups (control and vaginal dryness model). Vaginal oxygenation, blood flow and temperature were continuously monitored before and after sexual around induced by apomorphine. After the measurement, histologic examination was performed to support the results from DOS probe in the vaginal wall. The hemodynamic information acquired by the DOS probe can be utilized to establish an objective and accurate standard of the female sexual disorders.

  1. Effects of Reynolds and Womersley Numbers on the Hemodynamics of Intracranial Aneurysms

    Science.gov (United States)

    Asgharzadeh, Hafez

    2016-01-01

    The effects of Reynolds and Womersley numbers on the hemodynamics of two simplified intracranial aneurysms (IAs), that is, sidewall and bifurcation IAs, and a patient-specific IA are investigated using computational fluid dynamics. For this purpose, we carried out three numerical experiments for each IA with various Reynolds (Re = 145.45 to 378.79) and Womersley (Wo = 7.4 to 9.96) numbers. Although the dominant flow feature, which is the vortex ring formation, is similar for all test cases here, the propagation of the vortex ring is controlled by both Re and Wo in both simplified IAs (bifurcation and sidewall) and the patient-specific IA. The location of the vortex ring in all tested IAs is shown to be proportional to Re/Wo2 which is in agreement with empirical formulations for the location of a vortex ring in a tank. In sidewall IAs, the oscillatory shear index is shown to increase with Wo and 1/Re because the vortex reached the distal wall later in the cycle (higher resident time). However, this trend was not observed in the bifurcation IA because the stresses were dominated by particle trapping structures, which were absent at low Re = 151.51 in contrast to higher Re = 378.79. PMID:27847544

  2. Estimating Hemodynamic Responses to the Wingate Test Using Thoracic Impedance

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    Todd A. Astorino, Curtis Bovee, Ashley DeBoe

    2015-12-01

    Full Text Available Techniques including direct Fick and Doppler echocardiography are frequently used to assess hemodynamic responses to exercise. Thoracic impedance has been shown to be a noninvasive alternative to these methods for assessing these responses during graded exercise to exhaustion, yet its feasibility during supramaximal bouts of exercise is relatively unknown. We used thoracic impedance to estimate stroke volume (SV and cardiac output (CO during the Wingate test (WAnT and compared these values to those from graded exercise testing (GXT. Active men (n = 9 and women (n = 7 (mean age = 24.8 ± 5.9 yr completed two Wingate tests and two graded exercise tests on a cycle ergometer. During exercise, heart rate (HR, SV, and CO were continuously estimated using thoracic impedance. Repeated measures analysis of variance was used to identify potential differences in hemodynamic responses across protocols. Results: Maximal SV (138.6 ± 37.4 mL vs. 135.6 ± 26.9 mL and CO (24.5 ± 6.1 L·min-1 vs. 23.7 ± 5.1 L·min-1 were similar (p > 0.05 between repeated Wingate tests. Mean maximal HR was higher (p < 0.01 for GXT (185 ± 7 b·min-1 versus WAnT (177 ± 11 b·min-1, and mean SV was higher in response to WAnT (137.1 ± 32.1 mL versus GXT (123.0 ± 32.0 mL, leading to similar maximal cardiac output between WAnT and GXT (23.9 ± 5.6 L·min-1 vs. 22.5 ± 6.0 L·min-1. Our data show no difference in hemodynamic responses in response to repeated administrations of the Wingate test. In addition, the Wingate test elicits similar cardiac output compared to progressive cycling to VO2max.

  3. Value of portal hemodynamics and hypersplenism in cirrhosis staging

    Institute of Scientific and Technical Information of China (English)

    Bao-Min Shi; Xiu-Yan Wang; Qing-Ling Mu; Tai-Huang Wu; Jian Xu

    2005-01-01

    AIM: To determine the correlation between portal hemodynamics and spleen function among different grades of cirrhosis and verify its significance in cirrhosis staging.METHODS: The portal and splenic vein hemodynamics and spleen size were investigated by ultrasonography in consecutive 38 cirrhotic patients with cirrhosis (Child's grades A to C) and 20 normal controls. The differences were compared in portal vein diameter and flow velocity between patients with and without ascites and between patients with mild and severe esophageal varices. The correlation between peripheral blood cell counts and Child's grades was also determined.RESULTS: The portal flow velocity and volume were significantly lower in patients with Child's C (12.25±1.67 cm/s vs 788.59±234 mm/min, respectively) cirrhosis compared to controls (19.55±3.28 cm/s vs 1254.03±410 mm/min,respectively) and those with Child's A (18.5±3.02 cm/s vs1358.48±384 mm/min, respectively) and Child's B (16.0±3.89cm/s vs 1142.23±390 mm/min, respectively)cirrhosis.Patients with ascites had much lower portal flow velocity and volume (13.0±1.72 cm/s vs 1078±533 mm/min) than those without ascites (18.6±2.60 cm/s vs 1394±354 mm/min).There was no statistical difference between patients with mild and severe esophageal varices. The portal vein diameter was not significantly different among the above groups.There were significant differences in splenic vein diameter,flow velocity and white blood cell count, but not in spleen size, red blood cell and platelet counts among the various grades of cirrhosis. The spleen size was negatively correlated with red blood cell and platelet counts (r= -0.620and r = -0.8.34, respectively).CONCLUSION: An optimal system that includes parameters representing the portal hemodynamics and spleen function should be proposed for cirrhosis staging.

  4. Processing of Contrastiveness by Heritage Russian Bilinguals

    Science.gov (United States)

    Sekerina, Irina A.; Trueswell, John C.

    2011-01-01

    Two eye-tracking experiments in the Visual World paradigm compared how monolingual Russian (Experiment 1) and heritage Russian-English bilingual (Experiment 2) listeners process contrastiveness online in Russian. Materials were color adjective-noun phrases embedded into the split-constituent construction Krasnuju polozite zvezdovku..."Red put…

  5. Application of Contrast Echocardiography in Invasive Cardiology

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    Mustafa Bulut

    2010-12-01

    Full Text Available Contrast echocardiography by rendering better imaging of the borders of cardiac chambers is a useful tool for evaluating cardiac function, mass, myocardial vascularization, microvascular structure (small vessel vasculature and viability. Contrast was first started to be used for patients with suboptimal image quality. It can be used in detecting defects in myocardial blood supply in patients with chest pain and determining the success of interventionalprocedures. It can also be of help in demonstrating myocardial viability after reperfusion treatment in patients who had myocardial infarction. It is expected to be used more widely in invasive cardiology for decision making, guiding and determining the success of the procedures. Advances in imaging techniques , development of contrast materials for evaluation of left system, contrast echocardiography may become a routine clinical practice.

  6. Use of a Short-Acting β1 Blocker During Endotoxemia May Reduce Cerebral Tissue Oxygenation if Hemodynamics are Depressed by a Decrease in Heart Rate.

    Science.gov (United States)

    Kurita, Tadayoshi; Kawashima, Shingo; Morita, Koji; Nakajima, Yoshiki

    2017-06-01

    A decrease in heart rate (HR) using a short-acting β blocker has potential benefits in sepsis; however, depression of hemodynamics and reduction of cerebral oxygenation may also occur in endotoxemia. Seventeen swine were allocated to landiolol or control groups. In the landiolol group, the dose was sequentially changed from 0 to 40 to 200 μg kg min, and stopped. Hemodynamics, blood variables, and the cerebral tissue oxygenation index (TOI) were recorded by near infrared spectroscopy at each dose. Lipopolysaccharide (LPS) was then administered continuously at 1 μg kg h after a 100 μg bolus administration. After 30 and 150 min, as two severity stages of endotoxemia (endotoxemia 1 and 2), landiolol was administered as above and measurements were made. In the control group, landiolol was not administered, but measurements were made. LPS increased HR and landiolol decreased HR, with similar effects in each endotoxemia stage. In endotoxemia 1, LPS decreased stroke volume (SV), but landiolol restored SV to a value similar to that before endotoxemia, and did not decrease cardiac output (CO), even at 200 μg kg min. In contrast, landiolol did not restore SV in endotoxemia 2, resulting in a decrease in CO and mean arterial pressure, accompanied with a dose-dependent decrease in TOI. A short-acting β blocker has various hemodynamic effects in endotoxemia. Use of a short-acting β blocker during endotoxemia may reduce cerebral tissue oxygenation if hemodynamics are depressed by a decrease in HR.

  7. Efficient hemodynamic event detection utilizing relational databases and wavelet analysis

    Science.gov (United States)

    Saeed, M.; Mark, R. G.

    2001-01-01

    Development of a temporal query framework for time-oriented medical databases has hitherto been a challenging problem. We describe a novel method for the detection of hemodynamic events in multiparameter trends utilizing wavelet coefficients in a MySQL relational database. Storage of the wavelet coefficients allowed for a compact representation of the trends, and provided robust descriptors for the dynamics of the parameter time series. A data model was developed to allow for simplified queries along several dimensions and time scales. Of particular importance, the data model and wavelet framework allowed for queries to be processed with minimal table-join operations. A web-based search engine was developed to allow for user-defined queries. Typical queries required between 0.01 and 0.02 seconds, with at least two orders of magnitude improvement in speed over conventional queries. This powerful and innovative structure will facilitate research on large-scale time-oriented medical databases.

  8. The hemodynamics of septic shock: a historical perspective.

    Science.gov (United States)

    Feihl, Francois; Waeber, Bernard; Liaudet, Lucas

    2013-03-01

    In the late 19th century, it was already known that severe infections could be associated with cardiovascular collapse, a fact essentially attributed to cardiac failure. A major experimental work in the rabbit, published by Romberg and Pässler in 1899, shifted attention to disturbed peripheral vascular tone as the mechanism of hypotension in these conditions. In the first half of the 20th century, great progresses were made in the pathophysiologic understanding of hemorrhagic and traumatic shocks, while researchers devoted relatively little attention to septic shock. Progress in the hemodynamic understanding of septic shock resumed with the advent of critical care units. The hyperdynamic state was recognized in the late fifties and early sixties. The present short review ends with landmark studies by Max Harry Weil, demonstrating the importance of venous pooling, and John H. Siegel, which introduced the concept of deficient peripheral utilization of oxygen, inspiring later work on the microvascular disturbances of septic shock.

  9. Ocular hemodynamics in patients with rhegmatogenous retinal detachment

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    N. H. Zavgorodnya

    2014-10-01

    Full Text Available Aim. In case of retinal detachment atrophic processes lead to irreversible loss of functions within 4–6 days, it happens on underlying low ocular blood flow. In order to evaluate the degree of violation of regional hemodynamics in patients with retinal detachment two groups of patients were examined: the main group (52 patients with rhegmatogenous retinal detachment and the control group (24 myopic patients with lattice form of peripheral chorioretinal dystrophy. Methods and results. Doppler and reography results had been compared, significant decrease of blood flow in patients with retinal detachment was found. No differences between affected and fellow eye in these patients, close negative correlation between the level of ocular blood flow and the degree of myopia in the control group. Conclusion. This demonstrates the feasibility of actions to improve regional blood flow in patients operated on for retinal detachment.

  10. Vascular development and hemodynamic force in the mouse yolk sac

    Directory of Open Access Journals (Sweden)

    Monica D Garcia

    2014-08-01

    Full Text Available Vascular remodeling of the mouse embryonic yolk sac is a highly dynamic process dependent on multiple genetic signaling pathways as well as biomechanical factors regulating proliferation, differentiation, migration, cell-cell and cell-matrix interactions. During this early developmental window, the initial primitive vascular network of the yolk sac undergoes a dynamic remodeling process concurrent with the onset of blood flow, in which endothelial cells establish a branched, hierarchical structure of large vessels and smaller capillary beds. In this review, we will describe the molecular and biomechanical regulators which guide vascular remodeling in the mouse embryonic yolk sac, as well as live imaging methods for characterizing endothelial cell and hemodynamic function in cultured embryos.

  11. Hemodynamic changes after levothyroxine treatment in subclinical hypothyroidism

    DEFF Research Database (Denmark)

    Faber, J; Petersen, L; Wiinberg, N

    2002-01-01

    was then calculated as MAP/CO. Measurements were performed before and after 60 degrees head-up tilting, and before and after LT(4) substitution. Plasma levels of catecholamines were also measured. In 16 otherwise healthy women with SH (ages 44-74 years; serum TSH in mean 17.1 mU/L (range, 6.8-27), and normal free T(4.......05). These changes were qualitatively similar but quantitatively less pronounced than in 15 women with overt hypothyroidism, also studied. Taking the two groups together (n = 31), pretreatment thyroid function (expressed as either TSH or free T(4) estimate) correlated to CO and SVR as well as the changes induced...... by LT(4) (p changes in hemodynamic parameters of potentially beneficial character. SH and overt hypothyroidism should...

  12. Splanchnic and systemic hemodynamic derangement in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Bendtsen, F; Henriksen, Jens Henrik Sahl

    2001-01-01

    Patients with cirrhosis and portal hypertension exhibit characteristic hemodynamic changes with hyperkinetic systemic circulation, abnormal distribution of blood volume and neurohumoral dysregulation. Their plasma and noncentral blood volumes are increased. Splanchnic vasodilation is of pathogenic...... significance to the low systemic vascular resistance and abnormal volume distribution of blood, which are important elements in the development of the concomitant cardiac dysfunction, recently termed 'cirrhotic cardiomyopathy'. Systolic and diastolic functions are impaired with direct relation to the degree...... of liver dysfunction. Significant pathophysiological mechanisms are reduced beta-adrenergic receptor signal transduction, defective cardiac excitation-contraction coupling and conductance abnormalities. Vasodilators such as nitric oxide and calcitonin gene-related peptide are among the candidates...

  13. CFD modeling of pulsatile hemodynamics in the total cavopulmonary connection

    Science.gov (United States)

    Zobaer, S. M. Tareq; Hasan, A. B. M. Toufique

    2016-07-01

    Total cavopulmonary connection is a blood flow pathway which is created surgically by an operation known as Fontan procedure, performed on children with single ventricle heart defects. Recent studies have shown that the hemodynamics in the connection can be strongly influenced by the presence of pulsatile flow. The aim of this paper is model the pulsatile flow patterns, and to calculate the vorticity field and power losses in an idealized 1.5D offset model of Total Cavopulmonary Connection. A three-dimensional polyhedral mesh was constructed for the numerical simulation. The rheological properties of blood were considered as Newtonian, and flow in the connection was assumed to be laminar. The results demonstrated complex flow patterns in the connection. The outcomes of the simulation showed reasonable agreement with the results available in the literature for a similar model.

  14. Arteriovenous fistulas aggravate the hemodynamic effect of vein bypass stenoses

    DEFF Research Database (Denmark)

    Nielsen, T G; Djurhuus, C; Pedersen, Erik Morre;

    1996-01-01

    PURPOSE: The purpose of this study was to assess the impact of arteriovenous fistulas combined with varying degrees of stenosis on distal bypass hemodynamics and Doppler spectral parameters. METHODS: In an in vitro flow model bypass stenoses causing 30%, 55%, and 70% diameter reduction were induced...... 10 cm upstream of a fistula with low outflow resistance. Flow and intraluminal pressure were measured proximal to the stenosis and downstream of the fistula. The waveform parameters peak systolic velocity, end-diastolic velocity, pulsatility index, and pulse rise time were determined from midstream...... Doppler spectra obtained 10 cm downstream of the fistula. All measurements were carried out with open and clamped fistula. RESULTS: At 30% diameter reducing stenosis opening of the fistula induced a 12% systolic pressure drop across the stenosis but had no adverse effect on the Doppler waveform parameters...

  15. Current concepts on hemodynamic support and therapy in septic shock

    Directory of Open Access Journals (Sweden)

    Leonardo Lima Rocha

    2015-10-01

    Full Text Available ABSTRACTSevere sepsis and septic shock represent a major healthcare challenge. Much of the improvement in mortality associated with septic shock is related to early recognition combined with timely fluid resuscitation and adequate antibiotics administration. The main goals of septic shock resuscitation include intravascular replenishment, maintenance of adequate perfusion pressure and oxygen delivery to tissues. To achieve those goals, fluid responsiveness evaluation and complementary interventions - i.e. vasopressors, inotropes and blood transfusion - may be necessary. This article is a literature review of the available evidence on the initial hemodynamic support of the septic shock patients presenting to the emergency room or to the intensive care unit and the main interventions available to reach those targets, focusing on fluid and vasopressor therapy, blood transfusion and inotrope administration.

  16. Phase Contrast Imaging

    DEFF Research Database (Denmark)

    1996-01-01

    with a simple one-to-one mapping between resolution elements of a spatial phase modulator and resolution elements of the generated intensity pattern is provided. According to the invention a method is provided for synthesizing an intensity pattern with low loss of electromagnetic energy, comprising spatial...... modulation of electromagnetic radiation with a spatial phase mask for modulation of the phase of the incident eletromagnetic radiation by phasor values of individual resolution elements of the spatial phase mask, each phasor value being determined in such a way that the values of the Fourier transformed......The invention relates to a method and a system for synthesizing a prescribed intensity pattern based on phase contrast imaging that is not based on the assumption of prior art methods that the pahase shift phi is less than 1 radian. An improved method based on a simple imaging operation...

  17. Fast Computation of Hemodynamic Sensitivity to Lumen Segmentation Uncertainty.

    Science.gov (United States)

    Sankaran, Sethuraman; Grady, Leo; Taylor, Charles A

    2015-12-01

    Patient-specific blood flow modeling combining imaging data and computational fluid dynamics can aid in the assessment of coronary artery disease. Accurate coronary segmentation and realistic physiologic modeling of boundary conditions are important steps to ensure a high diagnostic performance. Segmentation of the coronary arteries can be constructed by a combination of automated algorithms with human review and editing. However, blood pressure and flow are not impacted equally by different local sections of the coronary artery tree. Focusing human review and editing towards regions that will most affect the subsequent simulations can significantly accelerate the review process. We define geometric sensitivity as the standard deviation in hemodynamics-derived metrics due to uncertainty in lumen segmentation. We develop a machine learning framework for estimating the geometric sensitivity in real time. Features used include geometric and clinical variables, and reduced-order models. We develop an anisotropic kernel regression method for assessment of lumen narrowing score, which is used as a feature in the machine learning algorithm. A multi-resolution sensitivity algorithm is introduced to hierarchically refine regions of high sensitivity so that we can quantify sensitivities to a desired spatial resolution. We show that the mean absolute error of the machine learning algorithm compared to 3D simulations is less than 0.01. We further demonstrate that sensitivity is not predicted simply by anatomic reduction but also encodes information about hemodynamics which in turn depends on downstream boundary conditions. This sensitivity approach can be extended to other systems such as cerebral flow, electro-mechanical simulations, etc.

  18. Leonardo da Vinci and the first hemodynamic observations.

    Science.gov (United States)

    Martins e Silva, J

    2008-02-01

    Leonardo da Vinci was a genius whose accomplishments and ideas come down to us today, five centuries later, with the freshness of innovation and the fascination of discovery. This brief review begins with a summary of Leonardo's life and a description of the most important works of art that he bequeathed us, and then concentrates on his last great challenge. There was a point at which Leonardo's passion for art gave way to the study of human anatomy, not only to improve his drawing but to go beyond what had been simply a representation of form to understand the underlying functioning. Among his many interests, we focus on his study of the heart and blood vessels, which he observed carefully in animals and human autopsies, and reproduced in drawings of great quality with annotations of astonishing acuteness. The experience that he had acquired from observing the flow of water in currents and around obstacles, and the conclusions that he drew concerning hydrodynamics, were central to his interpretation of the mechanisms of the heart and of blood flow, to which he devoted much of his time between 1508 and 1513. From these studies, immortalized in drawings of great clarity, come what are acknowledged to be the first hemodynamic records, in which Leonardo demonstrates the characteristics of blood flow in the aorta and great vessels and the importance of blood reflux and the formation of eddies in the sinus in aortic valve his assiduous and careful observations, and his subsequent deductions, Leonardo put forward detailed findings on hemodynamic questions that advanced technology has only recently enabled us to confirm.

  19. Mathematical simulation of hemodynamical processes and medical technologies

    Science.gov (United States)

    Tsitsyura, Nadiya; Novyc'kyy, Victor V.; Lushchyk, Ulyana B.

    2001-06-01

    Vascular pathologies constitute a significant part of human's diseases and their rate tends to increase. Numerous investigations of brain blood flow in a normal condition and in a pathological one has created a new branch of modern medicine -- angioneurology. It combines the information on brain angioarchitecture and on blood supply in a normal condition and in a pathological one. Investigations of a disease's development constitute an important problem of a modern medicine. Cerebrum blood supply is regulated by arterial inflow and venous outflow, but, unfortunately, in the literature available arterial and venous beds are considered separately. This causes an one-sided interpretation of atherosclerotical and discirculatory encefalopathies. As arterial inflow and venous outflow are interrelated, it seems to be expedient to perform a complex estimation of arteriovenous interactions, prove a correlation dependence connection between the beds and find a dependence in a form of mathematical function. The results will be observed clearly in the graphs. There were 139 patients aged from 2 up to 70 examined in the 'Istyna' Scientific Medical Ultrasound Center by means of a Logidop 2 apparatus manufactured by Kranzbuhler, Germany using a technique of cerebral arteries and veins ultrasound location (invented and patented by Ulyana Lushchyk, State Patent of Ukraine N10262 of 19/07/1995). A clinical interpretation of the results obtained was performed. With the help of this technique and ultrasound Dopplerography the blood flow in major head and cervical arteries was investigated. While performing a visual graphic analysis we paid attention to the changes of carotid artery (CA), internal jugular vein (IJV) and supratrochlear artery's (STA) hemodynamical parameters. Generally accepted blood flow parameters: FS -- maximal systolic frequency and FD -- minimal diastolic frequency were measured. The correlation between different combinations of parameters in the vessels mentioned

  20. Hemodynamic Effect of Laser Therapy in Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Suely Tomimura

    2014-08-01

    Full Text Available Systemic arterial hypertension (SAH is considered to be the greatest risk factor for the development of neuro-cardiovascular pathologies, thus constituting a severe Public Health issue in the world. The Low-Level Laser Therapy (LLLT, or laser therapy, activates components of the cellular structure, therefore converting luminous energy into photochemical energy and leading to biophysical and biochemical reactions in the mitochondrial respiratory chain. The LLLT promotes cellular and tissue photobiomodulation by means of changes in metabolism, leading to molecular, cellular and systemic changes. The objective of this study was to analyze the action of low-level laser in the hemodynamic modulation of spontaneously hypertensive rats, in the long term. Animals (n = 16 were randomly divided into the Laser Group (n = 8, which received three weekly LLLT irradiations for seven weeks, and into the Sham Group (n = 8, which received three weekly simulations of laser for seven weeks, accounting for 21 applications in each group. After seven weeks, animals were cannulated by the implantation of a catheter in the left carotid artery. On the following day, the systemic arterial pressure was recorded. The Laser Group showed reduced levels of mean blood pressure, with statistically significant reduction (169 ± 4 mmHg* vs. 182 ± 4 mmHg from the Sham Group and reduced levels of diastolic pressure (143 ± 4 mmHg* vs. 157 ± 3 mmHg from the Sham Group, revealing a 13 and 14 mmHg decrease, respectively. Besides, there was a concomitant important decline in heart rate (312 ± 14 bpm vs. 361 ± 13 bpm from the Sham Group. Therefore, laser therapy was able to produce hemodynamic changes, thus reducing pressure levels in spontaneously hypertensive rats.

  1. Hemodynamic parameters change earlier than tissue oxygen tension in hemorrhage.

    Science.gov (United States)

    Pestel, Gunther J; Fukui, Kimiko; Kimberger, Oliver; Hager, Helmut; Kurz, Andrea; Hiltebrand, Luzius B

    2010-05-15

    Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after preparation, baseline measurements were taken. At first, 5% of total blood volume was withdrawn, followed by another 5% increment, and then in 10% increments until death. After withdrawal of 5% of estimated blood volume, dPP increased from 6.1% +/- 3.0% to 20.8% +/- 2.7% (P < 0.01). Mean arterial pressure (MAP), mean pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) decreased with a blood loss of 10% (P < 0.01). Cardiac output (CO) changed after a blood loss of 20% (P < 0.05). Tissue oxygen tension in central organs, and blood flow in the jejunal muscularis decreased (P < 0.05) after a blood loss of 20%. Tissue oxygen tension in the skin, and jejunal mucosa blood flow decreased (P < 0.05) after a blood loss of 40% and 50%, respectively. In this hemorrhagic pig model systemic hemodynamic parameters were more sensitive to detect acute hypovolemia than tissue oxygen tension measurements or jejunal LDF measurements. Acute blood loss was detected first by dPP. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  2. Hemodynamic Effect of Laser Therapy in Spontaneously Hypertensive Rats

    Energy Technology Data Exchange (ETDEWEB)

    Tomimura, Suely, E-mail: suelytomimura@uol.com.br [Programa de Pós-Graduação em Biofotônica em Ciências da Saúde da Universidade Nove de Julho (UNINOVE) (Brazil); Silva, Bianca Passos Assumpção [Programa de Graduação e Pós-Graduação em Medicina da UNINOVE (Brazil); Sanches, Iris Callado [Laboratório de Fisiologia Translacional da UNINOVE (Brazil); Canal, Marina [Programa de Graduação e Pós-Graduação em Medicina da UNINOVE (Brazil); Consolim-Colombo, Fernanda [Programa de Graduação e Pós-Graduação em Medicina da UNINOVE (Brazil); Unidade de Hipertensão e Central Médica de Laser do Instituto do Coração - Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo (InCor/HC-FMUSP), São Paulo, SP (Brazil); Conti, Felipe Fernandes; Angelis, Katia De [Laboratório de Fisiologia Translacional da UNINOVE (Brazil); Chavantes, Maria Cristina [Programa de Pós-Graduação em Biofotônica em Ciências da Saúde da Universidade Nove de Julho (UNINOVE) (Brazil); Programa de Graduação e Pós-Graduação em Medicina da UNINOVE (Brazil); Unidade de Hipertensão e Central Médica de Laser do Instituto do Coração - Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo (InCor/HC-FMUSP), São Paulo, SP (Brazil)

    2014-08-15

    Systemic arterial hypertension (SAH) is considered to be the greatest risk factor for the development of neuro-cardiovascular pathologies, thus constituting a severe Public Health issue in the world. The Low-Level Laser Therapy (LLLT), or laser therapy, activates components of the cellular structure, therefore converting luminous energy into photochemical energy and leading to biophysical and biochemical reactions in the mitochondrial respiratory chain. The LLLT promotes cellular and tissue photobiomodulation by means of changes in metabolism, leading to molecular, cellular and systemic changes. The objective of this study was to analyze the action of low-level laser in the hemodynamic modulation of spontaneously hypertensive rats, in the long term. Animals (n = 16) were randomly divided into the Laser Group (n = 8), which received three weekly LLLT irradiations for seven weeks, and into the Sham Group (n = 8), which received three weekly simulations of laser for seven weeks, accounting for 21 applications in each group. After seven weeks, animals were cannulated by the implantation of a catheter in the left carotid artery. On the following day, the systemic arterial pressure was recorded. The Laser Group showed reduced levels of mean blood pressure, with statistically significant reduction (169 ± 4 mmHg* vs. 182 ± 4 mmHg from the Sham Group) and reduced levels of diastolic pressure (143 ± 4 mmHg* vs. 157 ± 3 mmHg from the Sham Group), revealing a 13 and 14 mmHg decrease, respectively. Besides, there was a concomitant important decline in heart rate (312 ± 14 bpm vs. 361 ± 13 bpm from the Sham Group). Therefore, laser therapy was able to produce hemodynamic changes, thus reducing pressure levels in spontaneously hypertensive rats.

  3. CONCENTRATION AND HEMODYNAMICS PATTERN CHANGES IN CIRRHOTIC RATS

    Institute of Scientific and Technical Information of China (English)

    黄颖秋; 萧树东; 莫剑忠; 张德中

    2000-01-01

    Objective To investigate the effects of hemoglobin (Hb) on serum nitric oxide (NO) concentration and hemodynamics pattern changes in rats with cirrhosis. Methods Cirrhosis model was induced in male SD rats by injection of 60% CCl4 oily solution subcutaneously. Cirrhotic rats were treated with erythropoietin (l00U/kg) injected subcutaneously for 2 weeks. Mean arterial pressure (MAP), cardiac output (CO), cardiac index (CI), splanchnic vascular resistance (SVR), splanchnic blood flow (SBF) and serum NO concentration were determined in erythropoietin - treated, erythropoietin - untreated cirrhotic rats and controls by using 57Co- labelled microsphere technique and a fluorometric assay, respectively. In addition, blood Hb levels were also measured in the 3 groups. Results Untreated cirrhotic rats had significantly lower MAP, SVR, Hb and higher CO, CI, SBF and NO concentration than those of the controls (P<0.01). In treated cirrhotic rats, erythropoietin significantly attenuated the increase of CO, CI, SBF, NO concentration and the decrease of MAP and SVR. In cirrhotic rats,epoetin beta in subcutaneous dose of 100U· kg-1· d-1 induced a markedly increment of blood Hb levels and decrement of NO concentration in comparison with untreated cirrhotic rats (181±11g/L vs 120±15g/L;1.14±0.62μmol/L vs 4.20±1.25μmol/L). Conclusion The endogenous NO may play an important role in the changes of hemodynamics pattern in cirrhosis, and hyperdynamic circulatory status in rats with cirrhosis might be ameliorated by inactivation of overproduced NO by increasing hemoglobin with erythropoietin.

  4. A study on cerebral hemodynamic analysis of moyamoya disease by using perfusion MRI

    Science.gov (United States)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-10-01

    This study examined the clinical applications of perfusion magnetic resonance imaging (MRI) in patients with moyamoya disease (MMD). Twenty-two patients with moyamoya disease (9 men and 13 women) with a mean age of 9.3 years (range: 4-22 years) were enrolled in this study. Perfusion MRI was performed by scanning the patients7.5 cm upward from the base of the cerebellum before their being process for post-treatment. The scan led to the acquisition of the following four map images: the cerebral blood volume (CBV), the cerebral blood flow (CBF), the mean transit time (MTT) for the contrast medium, and the time to peak (TTP) for the contrast medium. The lesions were assessed using the CBV, the CBF, the MTT and the TTP maps of perfusion MRI; the MTT and the TTP were measured in the lesion areas, as well as in the normal and the symmetric areas. Perfusion defects were recognizable in all four perfusion MRI maps, and the MTT and the TTP showed a conspicuous delay in the parts where perfusion defects were recognized. The MTT and the TTP images of perfusion MRI reflected a significant correlation between the degrees of stenosis and occlusion in the posterior cerebral artery (PCA), as well as the development of collateral vessels. The four perfusion MRI maps could be used to predict the degrees of stenosis and occlusion in the posterior circulation, as well as the development of the collateral vessels, which enabled a hemodynamic evaluation of the parts with perfusion defects. Overall, perfusion MRI is useful for the diagnosis and the treatment of moyamoya disease and can be applied to clinical practice.

  5. Characteristics of Hemodynamic Disorders in Patients with Severe Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Ryta E. Rzheutskaya

    2012-01-01

    Full Text Available Purpose. To define specific features of central hemodynamic parameter changes in patients with isolated severe traumatic brain injury (STBI and in patients with clinically established brain death and to determine the required course of treatment for their correction. Data and Research Methods. A close study of central hemodynamic parameters was undertaken. The study involved 13 patients with isolated STBI (group STBI and 15 patients with isolated STBI and clinically established brain death (group STBI-BD. The parameters of central hemodynamics were researched applying transpulmonary thermodilution. Results. In the present study, various types of hemodynamic reaction (normodynamic, hyperdynamic, and hypodynamic were identified in patients with isolated STBI in an acute period of traumatic disease. Hyperdynamic type of blood circulation was not observed in patients with isolated STBI and clinically established brain death. Detected hemodynamic disorders led to the correction of the ongoing therapy under the control of central hemodynamic parameters. Conclusions. Monitoring of parameters of central hemodynamics allows to detect the cause of disorders, to timely carry out the required correction, and to coordinate infusion, inotropic, and vasopressor therapy.

  6. Usefulness of Hemodynamic Sensors for Physiologic Cardiac Pacing in Heart Failure Patients

    Directory of Open Access Journals (Sweden)

    Eraldo Occhetta

    2011-01-01

    Full Text Available The rate adaptive sensors applied to cardiac pacing should respond as promptly as the normal sinus node with an highly specific and sensitive detection of the need of increasing heart rate. Sensors operating alone may not provide optimal heart responsiveness: central venous pH sensing, variations in the oxygen content of mixed venous blood, QT interval, breathing rate and pulmonary minute ventilation monitored by thoracic impedance variations, activity sensors. Using sensors that have different attributes but that work in a complementary manners offers distinct advantages. However, complicated sensors interactions may occur. Hemodynamic sensors detect changes in the hemodynamic performances of the heart, which partially depends on the autonomic nervous system-induced inotropic regulation of myocardial fibers. Specific hemodynamic sensors have been designed to measure different expression of the cardiac contraction strength: Peak Endocardial Acceleration (PEA, Closed Loop Stimulation (CLS and TransValvular Impedance (TVI, guided by intraventricular impedance variations. Rate-responsive pacing is just one of the potential applications of hemodynamic sensors in implantable pacemakers. Other issues discussed in the paper include: hemodynamic monitoring for the optimal programmation and follow up of patients with cardiac resynchronization therapy; hemodynamic deterioration impact of tachyarrhythmias; hemodynamic upper rate limit control; monitoring and prevention of vasovagal malignant syncopes.

  7. Association of Central Sleep Apnea with Impaired Heart Structure and Cardiovascular Hemodynamics in Patients with Chronic Heart Failure.

    Science.gov (United States)

    Kazimierczak, Anna; Krzesiński, Paweł; Gielerak, Grzegorz; Uziębło-Życzkowska, Beata; Smurzyński, Paweł; Ryczek, Robert; Cwetsch, Andrzej; Skrobowski, Andrzej

    2016-08-25

    BACKGROUND Advanced heart failure (HF) is commonly accompanied by central sleep apnea (CSA) with Cheyne-Stokes respiration (CSR). The aim of this study was to evaluate the relationship between CSA/CSR and other clinical features of HF, with particular emphasis on cardiovascular hemodynamics. MATERIAL AND METHODS In 161 stable HF patients with left ventricular ejection fraction (LVEF) ≤45% (NYHA class I-III; mean LVEF 32.8%) the clinical evaluation included: LVEF; left and right ventricular end-diastolic diameter (LVDd, RVDd); ratio of early transmitral flow velocity to early diastolic septal mitral annulus velocity (E/e') assessed by echocardiography; stroke index (SI); heart rate (HR); cardiac index (CI); and systemic vascular resistance index (SVRI) assessed by impedance cardiography (ICG). The comparison was performed between 2 subgroups: one with moderate/severe CSA/CSR - CSR_ [+] (n=51), and one with mild or no CSA/CSR - CSR_ [-] (n=110). RESULTS CSR_ [+] patients presented more advanced NYHA class (pCSR_ [+] were identified: NYHA class (OR=3.34 per class, pCSR in HF is associated with NYHA class, atrial fibrillation and more advanced impairment of cardiovascular structure and hemodynamics. Patient functional state remains the main determinant of CSR.

  8. Association of Central Sleep Apnea with Impaired Heart Structure and Cardiovascular Hemodynamics in Patients with Chronic Heart Failure

    Science.gov (United States)

    Kazimierczak, Anna; Krzesiński, Paweł; Gielerak, Grzegorz; Uziebło-Życzkowska, Beata; Smurzyński, Paweł; Ryczek, Robert; Cwetsch, Andrzej; Skrobowski, Andrzej

    2016-01-01

    Background Advanced heart failure (HF) is commonly accompanied by central sleep apnea (CSA) with Cheyne-Stokes respiration (CSR). The aim of this study was to evaluate the relationship between CSA/CSR and other clinical features of HF, with particular emphasis on cardiovascular hemodynamics. Material/Methods In 161 stable HF patients with left ventricular ejection fraction (LVEF) ≤45% (NYHA class I–III; mean LVEF 32.8%) the clinical evaluation included: LVEF; left and right ventricular end-diastolic diameter (LVDd, RVDd); ratio of early transmitral flow velocity to early diastolic septal mitral annulus velocity (E/e’) assessed by echocardiography; stroke index (SI); heart rate (HR); cardiac index (CI); and systemic vascular resistance index (SVRI) assessed by impedance cardiography (ICG). The comparison was performed between 2 subgroups: one with moderate/severe CSA/CSR - CSR_ [+] (n=51), and one with mild or no CSA/CSR – CSR_ [−] (n=110). Results CSR_ [+] patients presented more advanced NYHA class (pCSR_ [+] were identified: NYHA class (OR=3.34 per class, pCSR in HF is associated with NYHA class, atrial fibrillation and more advanced impairment of cardiovascular structure and hemodynamics. Patient functional state remains the main determinant of CSR. PMID:27558771

  9. Children with hemodynamically significant congenital heart disease can be identified through population-based registers

    DEFF Research Database (Denmark)

    Bergman, Gunnar; Hærskjold, Ann; Stensballe, Lone Graff

    2015-01-01

    is indicated as a prophylactic treatment against respiratory syncytial virus infections in children with hemodynamically significant CHD. AIM: The aim of the study reported here was to develop and validate an algorithm to identify children with hemodynamically significant CHD according to recommendations...... for palivizumab prophylaxis in register-based research. METHODS: By using a strategy of combining criteria for age at diagnosis, diagnostic codes, surgical procedure codes, and dispensing records, we created an algorithm to define the specific cases with hemodynamically significant CHD in which palivizumab could...

  10. The direct effect of incretin hormones on glucose and glycerol metabolism and hemodynamics

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Mortensen, Stefan; Knudsen, Sine H;

    2015-01-01

    The objective of this study was to assess the insulin-independent effects of incretin hormones on glucose and glycerol metabolism and hemodynamics under eu- and hyperglycemic conditions. Young, healthy males (n=10) underwent three trials in a randomized, controlled, cross-over study. Each trial...... consisted of a 2-stage (eu- and hyperglycemia) pancreatic clamp (using somatostatin to prevent endogenous insulin secretion). Glucose and lipid metabolism were measured via infusion of stable glucose and glycerol isotopic tracers. Hemodynamic variables (femoral, brachial and common carotid artery blood flow...... a higher femoral blood flow during hyperglycemia in GIP (vs. CON and GLP-1, Pmetabolism or hemodynamics during euglycemia. On contrary, during...

  11. Blood flow contrast enhancement in optical coherence tomography using microbubbles: a phantom study

    Science.gov (United States)

    Assadi, Homa; Demidov, Valentin; Karshafian, Raffi; Douplik, Alexandre; Vitkin, I. Alex

    2016-03-01

    In this study gas microbubbles are investigated as intravascular OCT contrast agents. Agar+Intralipid scattering tissue-like phantoms with two embedded microtubes were fabricated to model vascular blood flow. One was filled with human blood, and the other with a mixture of human blood and microbubbles. Swept-source structural and speckle variance OCT images, as well as speckle decorrelation times, were evaluated under both stationary and flow conditions. Faster decorrelation times and higher image contrast were detected in the presence of microbubbles in all experiments, and the effect was largest for speckle variance OCT ~2.3x greater contrast under flow conditions. The feasibility of utilizing microbubbles for tissue hemodynamic investigations and for microvasculature contrast enhancement in OCT angiography thus appears promising.

  12. Diagnosis and treatment guidelines for aberrant portal hemodynamics: The Aberrant Portal Hemodynamics Study Group supported by the Ministry of Health, Labor and Welfare of Japan.

    Science.gov (United States)

    2017-01-06

    Idiopathic portal hypertension (IPH), causing aberrant portal hemodynamics, is a disease with an as yet unidentified cause and no established treatment protocol. The Japanese research group on IPH in Japan was set up in 1975 by the Ministry of Health, Labor and Welfare. Extrahepatic portal obstruction and Budd-Chiari syndrome (BCS) have since been added to the group's research subjects. The aims of the research group are to accurately evaluate the current status of the three diseases in Japan, elucidate their etiology and pathogenesis, and develop new treatments. Due to the long-term efforts of the Japanese research group, aberrant portal hemodynamics has been investigated in a variety of aspects, from epidemiological and pathological studies to molecular biology analyses. As a result, it has been shown that there are abnormal genes in the liver, specific for IPH. In addition, pathological findings of BCS were internationally compared and the difference in findings between Japan and Europe (or North America) has been clarified. Furthermore, it was found that complication rates of hepatocellular carcinoma in BCS were higher in Japan. Based on the research, "Diagnosis and treatment of aberrant portal hemodynamics (2001)", including diagnostic criteria for aberrant portal hemodynamics, was published in 2001. In 2013, it was revised to "Diagnosis and treatment guidelines for aberrant portal hemodynamics (2013)" after the incorporation of diagnosis and treatment in accordance with its current status.

  13. Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    The paper deals with the infrared flash thermography inspection to detect and analyze delamination-like anomalies in nonmetallic materials. It provides information on an IR Contrast technique that involves extracting normalized contrast verses time evolutions from the flash thermography infrared video data. The paper provides the analytical model used in the simulation of infrared image contrast. The contrast evolution simulation is achieved through calibration on measured contrast evolutions from many flat bottom holes in the subject material. The paper also provides formulas to calculate values of the thermal measurement features from the measured contrast evolution curve. Many thermal measurement features of the contrast evolution that relate to the anomaly characteristics are calculated. The measurement features and the contrast simulation are used to evaluate flash thermography inspection data in order to characterize the delamination-like anomalies. In addition, the contrast evolution prediction is matched to the measured anomaly contrast evolution to provide an assessment of the anomaly depth and width in terms of depth and diameter of the corresponding equivalent flat-bottom hole (EFBH) or equivalent uniform gap (EUG). The paper provides anomaly edge detection technique called the half-max technique which is also used to estimate width of an indication. The EFBH/EUG and half-max width estimations are used to assess anomaly size. The paper also provides some information on the "IR Contrast" software application, half-max technique and IR Contrast feature imaging application, which are based on models provided in this paper.

  14. Correlations Between the Gradient of Contrast Density, Evaluated by Cardio CT, and Functional Significance of Coronary Artery Stenosis

    Directory of Open Access Journals (Sweden)

    Orzan Marius

    2016-06-01

    Full Text Available Background: Assessment of the hemodynamic significance of a coronary artery stenosis is a challenging task, being extremely important for the establishment of indication for revascularization in atherosclerotic coronary artery stenosis. The aim of this study was to evaluate the role of a new marker reflecting the functional significance of a coronary artery stenosis, represented by the attenuation degree of contrast density along the stenosis by Coronary CT.

  15. RENAL HEMODYNAMICS AND GLOMERULAR FILTRATION RATE IN MEN AND WOMEN WITH ARTERIAL HYPERTENSION AT THE AGE OF 40-60 YEARS

    Directory of Open Access Journals (Sweden)

    I. G. Fomina

    2015-12-01

    Full Text Available Aim. To study parameters of a renal hemodynamic and the general glomerular filtration rate (GGFR and their correlations with cardiovascular risk factors (RF in patient with arterial hypertension (AH.Material and methods. 102 patients with AH (35 men and 67 women of 40-60 y.o. were involved in the study. 20 persons (10 men and 10 women with normal blood pressure (BP were included in control group. Dynamic renal angioscintigraphy was used for an estimation of a renal hemodynamic and GGFR.Results. Hypertensive women had lower renal blood flow and GGFR than these in men (p<0,000. Renal hemodynamics and GGFR in men and women did not differ in control group. Positive correlation  r=0,61; p<0,05 between GGFR and a tobacco smoking was found in hypertensive men as well as negative correlation (r=-0,41; p<0,005 between GGFR and body mass index (BMI in women.Conclusion. Renal blood flow and GGFR are lower in hypertensive women than these in men. Positive correlation between GGFR and tobacco smoking and negative correlation between GGFR and BMI were found in men and women respectively.

  16. Pulsatile Support Mode of BJUT-II Ventricular Assist Device (VAD) has Better Hemodynamic Effects on the Aorta than Constant Speed Mode: A Primary Numerical Study.

    Science.gov (United States)

    Gu, Kaiyun; Gao, Bin; Chang, Yu; Zeng, Yi

    2016-07-01

    BACKGROUND BJUT-II VAD is a novel left ventricular assist device (LVADs), directly implanted into the ascending aorta. The pulsatile support mode is proposed to achieve better unloading performance than constant speed mode. However, the hemodynamic effects of this support mode on the aorta are still unclear. The aim of this study was to clarify the hemodynamic effects BJUT-II VAD under pulsatile support mode on the aorta. MATERIAL AND METHODS Computational fluid dynamics (CFD) studies, based on a patient-specific aortic geometric model, were conducted. Wall shear stress (WSS), averaged WSS (avWSS), oscillatory shear index (OSI), and averaged helicity density (Ha) were calculated to compare the differences in hemodynamic effects between pulsatile support mode and constant speed mode. RESULTS The results show that avWSS under pulsatile support mode is significantly higher than that under constant speed mode (0.955Pa vs. 0.675Pa). Similarly, the OSI value under pulsatile mode is higher than that under constant speed mode (0.104 vs. 0.057). In addition, Ha under pulsatile mode for all selected cross-sections is larger than that under constant mode. CONCLUSIONS BJUT-II VAD, under pulsatile control mode, may prevent atherosclerosis lesions and aortic remodeling. The precise effects of pulsatile support mode on atherosclerosis and aortic remodeling need to be further studied in animal experiments.

  17. Optically measured microvascular blood flow contrast of malignant breast tumors.

    Directory of Open Access Journals (Sweden)

    Regine Choe

    Full Text Available Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS, a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92-2.63; tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94-2.66, and using normal tissue in the contralateral breast was 2.27 (1.90-2.70. Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography.

  18. Contrast-enhanced MR angiography in patients after kidney transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Huber, A.; Heuck, A.; Scheidler, J.; Holzknecht, N.; Baur, A.; Reiser, M. [Klinikum Grosshadern, Muenchen (Germany). Radiologische Klinik und Poliklinik; Stangl, M.; Theodorakis, J.; Illner, W.-D.; Land, W. [Dept. of Transplant Surgery, Klinikum Grosshadern, Muenchen (Germany)

    2001-12-01

    The aim of this study was to investigate the value of a contrast-enhanced 3D MR angiography in detecting postoperative vascular complications after kidney transplantation in comparison with digital subtraction angiography (DSA). Forty-one patients who underwent a kidney transplantation were examined with MR angiography and DSA. Contrast-enhanced MR angiography was performed as a dynamic measurement with one precontrast and three postcontrast measurements. Maximum intensity projection reconstructions were performed for all postcontrast data sets after DSA. The results were evaluated by two independent observers who were unaware of the DSA results. Twenty-three hemodynamically significant arterial stenoses were identified with DSA in the iliac arteries (n=7), the renal allograft arteries (n=12), and in their first branches (n=4). For a patient-based analysis the sensitivity and specificity, respectively, for observer 1 were 100 and 97%, and for observer 2, 100 and 93%. Respective data were 100 and 100% after a consensus evaluation by two observers. Complications involving the renal veins were detected in 2 cases and perfusion defects of the kidney parenchyma were detected in 4 cases. Contrast-enhanced MR angiography is a reliable method in identifying postoperative arterial stenoses after kidney transplantation. In addition, dynamic MR angiography can be helpful in detecting venous complications and perfusion defects in kidney allografts. (orig.)

  19. Cardioselectivity, kinetics, hemodynamics, and metabolic effects of xamoterol.

    Science.gov (United States)

    Jennings, G; Bobik, A; Oddie, C; Restall, R

    1984-05-01

    Xamoterol is a new orally active partial beta-adrenoceptor agonist. Its kinetics, hemodynamic and metabolic effects, and cardioselectivity were investigated in eight normal subjects. Plasma xamoterol concentrations after 100 micrograms/kg iv declined biexponentially over 8 hr and t 1/2 beta averaged 2.6 hr. Resting heart rate (HR) increased slightly in the supine position but was unchanged on sitting. Systolic blood pressure (SBP) rose by 5 to 10 mm Hg and cardiac index (CI) rose 15% to 20%. Both parameters were above control values 6 hr after dosing, when plasma xamoterol concentrations had fallen to about 10 ng/ml. There were no changes in diastolic or mean arterial pressure (MAP). During graded exercise the effects of xamoterol on HR and SBP were the reverse of those at rest, with lowering of exercise HR and SBP at higher work loads. CI during exercise was not altered by xamoterol. Doses of xamoterol were calculated from the kinetic data to give plasma concentrations of 100, 200, 400, and 800 ng/ml. HR and blood pressure effects at each xamoterol level were compared before and after inhibition of cardiovascular reflexes with prazosin, atropine, and clonidine. Hemodynamic effects of xamoterol and isoproterenol were compared. Before autonomic block xamoterol increased HR by 10 bpm and MAP by 7 mm Hg at the highest dose. After autonomic block there was a 200% to 300% rise in HR at each dose and MAP still rose. The rise in MAP after block could be entirely accounted for by a 23% increase in CI because total peripheral resistance did not change. The effects of isoproterenol after autonomic block were a rise in HR and a fall in MAP. Metabolic responses to xamoterol were measured at the four dose levels. There was a dose-related increase in nonesterified fatty acids and a fall in plasma lactate levels but no changes in plasma renin activity or blood glucose. Results suggest that xamoterol is a cardioselective partial beta-adrenoceptor agonist in man.

  20. A New Hemodynamic Ex Vivo Model for Medical Devices Assessment.

    Science.gov (United States)

    Maurel, Blandine; Sarraf, Christophe; Bakir, Farid; Chai, Feng; Maton, Mickael; Sobocinski, Jonathan; Hertault, Adrien; Blanchemain, Nicolas; Haulon, Stephan; Lermusiaux, Patrick

    2015-11-01

    In-stent restenosis (ISR) remains a major public health concern associated with an increased morbidity, mortality, and health-related costs. Drug-eluting stents (DES) have reduced ISR, but generate healing-related issues or hypersensitivity reactions, leading to an increased risk of late acute stent thrombosis. Assessments of new DES are based on animal models or in vitro release systems, which have several limitations. The role of flow and shear stress on endothelial cell and ISR has also been emphasized. The aim of this work was to design and first evaluate an original bioreactor, replicating ex vivo hemodynamic and biological conditions similar to human conditions, to further evaluate new DES. This bioreactor was designed to study up to 6 stented arteries connected in bypass, immersed in a culture box, in which circulated a physiological systolo-diastolic resistive flow. Two centrifugal pumps drove the flow. The main pump generated pulsating flows by modulation of rotation velocity, and the second pump worked at constant rotation velocity, ensuring the counter pressure levels and backflows. The flow rate, the velocity profile, the arterial pressure, and the resistance of the flow were adjustable. The bioreactor was placed in an incubator to reproduce a biological environment. A first feasibility experience was performed over a 24-day period. Three rat aortic thoracic arteries were placed into the bioreactor, immersed in cell culture medium changed every 3 days, and with a circulating systolic and diastolic flux during the entire experimentation. There was no infection and no leak. At the end of the experimentation, a morphometric analysis was performed confirming the viability of the arteries. We designed and patented an original hemodynamic ex vivo model to further study new DES, as well as a wide range of vascular diseases and medical devices. This bioreactor will allow characterization of the velocity field and drug transfers within a stented artery with new

  1. Evaluation of hemodynamic and SpO2 variability during different stages of periodontal surgery

    Directory of Open Access Journals (Sweden)

    Babak Amoian

    2013-01-01

    Full Text Available Background: Changes in pulse rate and blood pressure are common consequences during oral surgeries. Hypoxia during surgical process is another side effect. The objective of the present study was evaluation of blood hemoglobin oxygenation and hemodynamic changes during periodontal surgery. Materials and Methods: This clinical trial study was conducted upon 50 subjects aged 30-55 years who referred to the clinic of dental faculty of Babol University and needed periodontal surgery with modified widman flaps in the anterior section of the maxilla. Pulse rate, blood pressure, and pulse oximetric evaluations were recorded in five stages during surgery. Results: The average of systolic and diastolic blood pressure had been in their maximum amount in the second stage of evaluation and minimum amounts were in the first one; while pulse rate changes were greatest in the second stage and lowest in the fifth stage. Analyzing the data revealed no significant difference in Blood Oxygen Saturation (SpO2 measurements in none of the stages evaluated. Conclusions: Blood pressure and heart rate increased significantly after the injection of anesthetic drug and in further phases they were decreased after the elimination of stimulating effect of adrenaline. SpO 2 changes were not significantly prominent.

  2. EFFECTS OF AMLODIPINE, FOSINOPRIL AND METOPROLOL ON HEMODYNAMICS IN HYPERTENSIVE PATIENTS

    Directory of Open Access Journals (Sweden)

    A. L. Hohlov

    2007-01-01

    Full Text Available Aim. To assess an efficacy of antihypertensive therapy with calcium antagonist, angiotensin converting enzyme inhibitor and β-blocker in patients with arterial hypertension (AH taking into account influence on central and peripheral hemodynamics.Material and methods. 60 patients with AH of I-II stage, 1-2 grade were studied. They were split in 3 groups. Patients of the first group received amlodipine (Tenox, 5-10 mg/d, the second group – fosinopril (Monopril, 10-20 mg/d and the third group – metoprolol (Metocard, 50-200 mg/d.Diuretics were added when necessary. Ambulatory blood pressure (BP monitoring, echocardiography, ultrasound investigation of brachiocephalic and main cerebral arteries, test on reactive hyperemia and nitroglycerine were conducted before and after 6 months of therapy.Results. Amlodipine, fosinopril and metoprolol had similar antihypertensive effect. Amlodipine was more effective in comparison with fosinopril and metoprolol in reduction of left ventricular (LV myocardial mass and improving of LV diastolic function. Amlodipine and fosinopril had positive effect on vascular remodeling. Metoprolol reduced in BP morning elevation and heart rate, but had no effect on systolic BP variability.Conclusion. Amlodipine, fosinopril and metoprolol have similar antihypertensive effect but different influence on the heart, arteries, BP variability and hemodinamics.

  3. EFFECT OF ANTIVIRAL THERAPY ON HEART AND LIVER HEMODYNAMICS IN PATIENTS WITH VIRAL CIRRHOSIS

    Directory of Open Access Journals (Sweden)

    M. V. Chistyakova

    2014-01-01

    Full Text Available Aim. To study the effect of antiviral therapy on some hemodynamic parameters of the heart and the liver in patients with viral cirrhosis.Material and methods. In 75 patients with chronic viral cirrhosis evaluation of segmental systolic and diastolic function using pulsed tissue Doppler mapping and global diastolic function by the method of Doppler echocardiography was performed. Blood flow in the veins of the liver was determined by means of ultrasonic Dopplerography. 16 patients had previously received antiviral therapy - interferon combined with ribavirin - with the formation of a sustained virologic response (1st group, the remaining 59 (2nd group had never received antiviral therapy. The control group consisted of 19 healthy individuals.Results. In patients with chronic viral cirrhosis the increase of the left atrium, diastolic and systolic dimensions, sphericity index and left ventricle mass (p<0.001 were revealed. The right ventricle increased in size with the impairment of its diastolic function and the reduction in longitudinal systolic velocity while pulmonary artery and its branches expanded with the increase of flow velocity in it (p<0.001. Dilation of the splenic vein in the 1st (30% and 2nd groups (46% was detected as compared with the control group (p<0.001. Standard deviation normal to normal (SDNN of RR interval durations reflecting general autonomic tone increased in the 1st and 2nd groups and it was 42% and 62% lower, respectively, in comparison with this index in the control group (p<0.001. These disorders prevailed in patients who were not receiving antiviral therapy, moreover, they showed acceleration of blood flow in the hepatic vein and reduction in longitudinal systolic velocity at the fibrous ring of the mitral valve (p<0.001. The correlation between systolic velocity on the fibrous ring of the mitral valve, high viral load and a diameter of splenic vein was revealed.Conclusion. Evidence suggests that patients not

  4. Exercise hemodynamics in patients with and without diastolic dysfunction and preserved ejection fraction after myocardial infarction

    DEFF Research Database (Denmark)

    Andersen, Mads J; Ersbøll, Mads; Bro-Jeppesen, John

    2012-01-01

    Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress....

  5. Effect of fiberoptic bronchoscope compared with direct laryngoscope on hemodynamic responses to orotracheal intubation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-hua; XUE Fu-shan; LI Ping; SUN Hai-yan; LIU Kun-peng; XU Ya-chao; LIU Yi; SUN Hai-tao

    2007-01-01

    @@ Fiberoptic bronchoscope (FOB) is an important instrument for respiratory, disorder examination and difficult airway management.1 The fiberoptic intubation can avoid the mechanical stimulus to oropharyngolaryngeal structures thereby it is likely to attenuate hemodynamic responses during orotracheal intubation.

  6. Comparison of the hemodynamic effects of etomidate between hypertensive and normotensive patients

    Directory of Open Access Journals (Sweden)

    Hayrettin Daşkaya

    2014-06-01

    Full Text Available Objective: Comparison of the hemodynamic effect of ethomidate induction in normotensive and hypertensive patients. Methods: Forty ASA 1-2 patients were included. After informed consent were obtained, patients were divided into two group; Group H: Hypertensive patients, Group N: Normotensive patients. Fentanile and midazolam were administrated for premedication. Anesthesia induction was performed by etomidate 0.3 mg/kg and rocuronium 0.6 mg/kg. Arterial pressures and heart rates were measured at certain intervals: control, pre-intubation and 1, 3 and 5 min post-intubation. Myoclonic movements and hemodynamic parameters were noted by an anesthetist who was masked to the groups. Results: Hemodynamic parameters were higher in hypertensive patients but were in clinically tolerable limits. Conclusion: No hemodynamic instability was observed in anesthesia induction with ethomidate in neither hypertensive nor normotensive patients. J Clin Exp Invest 2014; 5 (2: 164-168

  7. Oral premedication with pregabalin and clonidine for hemodynamic stability during laryngoscopy: A comparative study

    Directory of Open Access Journals (Sweden)

    Asmita Chaudhary

    2015-04-01

    Conclusion: Hemodynamic pressure response of airway instrumentation was attenuated with pregabalin and clonidine oral premedication without prolongation of recovery time and side effects. [Int J Basic Clin Pharmacol 2015; 4(2.000: 294-299

  8. Survival function Of Realization process for Hemodynamic and hormonal effects of human GH in healthy volunteers

    Directory of Open Access Journals (Sweden)

    Geetha.T

    2014-12-01

    Full Text Available Hemodynamic and hormonal effects of human ghrelin in healthy volunteers. To investigate hemodynamic and hormonal effects of ghrelin, a novel growth hormone (GH-releasing peptide, we gave six healthy men an intravenous bolus of human ghrelin or placebo and vice versa 1–2 wk apart in a randomized fashion. Ghrelin elicited a marked increase in circulating GH. The elevation of GH lasted longer than 60 min after the bolus injection. Injection of ghrelin significantly decreased mean arterial pressure without a significant change in heart rate .In summary, human ghrelin elicited a potent, long lasting GH release and had beneficial hemodynamic effects via reducing cardiac after load and increasing cardiac output without an increase in heart rate. Thus, the purpose of this study was to investigate hemodynamic and hormonal effects of intravenous ghrelin in healthy volunteers. This paper discussed the constant stress level of healthy volunteers with times to damage of stress effect and recoveries

  9. Transitional cardiovascular physiology and comprehensive hemodynamic monitoring in the neonate: relevance to research and clinical care.

    Science.gov (United States)

    Azhibekov, Timur; Noori, Shahab; Soleymani, Sadaf; Seri, Istvan

    2014-02-01

    A thorough understanding of developmental cardiovascular physiology is essential for early recognition of cardiovascular compromise, selective screening of at-risk groups of neonates, and individualized management using pathophysiology-targeted interventions. Although we have gained a better understanding of the physiology and pathophysiology of postnatal cardiovascular transition over the past decade with the use of sophisticated methods to study neonatal hemodynamics, most aspects of neonatal hemodynamics remain incompletely understood. In addition, targeted therapeutic interventions of neonatal hemodynamic compromise have not been shown to improve mortality and clinically relevant outcomes. However, the recent development of comprehensive hemodynamic monitoring systems capable of non-invasive, continuous and simultaneous bedside assessment of cardiac output, organ blood flow, microcirculation, and tissue oxygen delivery has made sophisticated analysis of the obtained physiologic data possible and has created new research opportunities with the potential of direct implications to patient care.

  10. Hemodynamics and early recovery characteristics of desflurane versus sevoflurane in bariatric surgery

    Directory of Open Access Journals (Sweden)

    Amandeep Kaur

    2013-01-01

    Conclusions: Both desflurane and sevoflurane produce similar hemodynamic changes but the immediate and intermediate recovery was significantly faster after desflurane thus contributing to fast tracking and early discharge of patients.

  11. A cohort study on the relationship between cerebrovascular hemodynamic changing and risk of strok

    Institute of Scientific and Technical Information of China (English)

    郭吉平

    2013-01-01

    Objective To study the role of cerebrovascular hemodynamic indexes(CVHI)changing in stroke and to provide reference for stroke prevention and risk factor study.Methods From 2003 to 2004,participants aged 40 years

  12. Hemodynamic study of hepatocellular car-cinoma nodules by multi-slice spiral computed tomographic perfusion

    Institute of Scientific and Technical Information of China (English)

    马国林

    2013-01-01

    Objective To analyze the 64-slice computed tomographic(CT) perfusion parameters of hepatocellular carcinoma(HCC) nodule so as to assess the diagnostic value of hemodynamic changes of HCC nodule by this perfusion

  13. Phase-contrast X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi [Hitachi Ltd., Hatoyama, Saitama (Japan). Advanced Research Lab.

    1996-08-01

    X-ray transmission imaging that creates image contrast from the distribution of the X-ray absorption coefficient is not sensitive to materials consisting of light elements such as hydrogen, carbon, nitrogen, and oxygen. On the other hand, the X-ray phase shift caused by the light elements is substantial enough to be detected even when absorption is almost zero. Hence, phase-contrast X-ray imaging is a promising technique for observing the structure inside biological soft tissues without the need for staining and without serious radiation exposure. Using fringe scanning X-ray interferometry, the X-ray phase shift caused by an object was measured. Three-dimensional image reconstruction of cancerous tissues using the measured phase shifts was enabled under tomographic configuration phase-contrast X-ray computed tomography (CT). (author)

  14. Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures.

    Science.gov (United States)

    Wong, Kelvin K L; Wang, Defeng; Ko, Jacky K L; Mazumdar, Jagannath; Le, Thu-Thao; Ghista, Dhanjoo

    2017-03-21

    Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.

  15. Temporal analysis of fluctuations in cerebral hemodynamics revealed by near-infrared spectroscopy

    Science.gov (United States)

    Toronov, Vlad; Fantini, Sergio; Franceschini, Maria-Angela; Filiaci, Mattia A.; Wolf, Martin; Gratton, Enrico

    2000-04-01

    We have non-invasively studied the motor cortex hemodynamics in human subjects under rest and motor stimulation conditions using a multichannel near-IR tissue spectrometer. We obtained optical maps of oxy- and deoxy-hemoglobin concentration changes in terms of amplitudes of folding average, power spectrum and coherence at the stimulation repetition frequency, and the phase synchronization index. Under periodic motor stimulation conditions, we observed coherence and phase synchronization of the local hemodynamic changes with stimulation.

  16. Evaluation of the relative risk of stroke in patients with hypertension using cerebrovascular hemodynamic accumulative score

    Institute of Scientific and Technical Information of China (English)

    HUANG Jiuyi; WANG Guiqing; GUO Jiping; CAO Yifeng; WANG Yan; YANG Yongju; YU Xuehai

    2007-01-01

    The relative risk(RR)of stroke in patients with hypertension was evaluated by using synthetic index of cerebrovascular hemodynamics.A total of 7,371 patients with hypertension with ages≥40 years were selected from a population-based cohort study of the risk factors for stroke.The data on the baseline investigation of risk factors,the determination of cerebrovascular hemodynamic parameters (CVHP),and stroke follow-up were analyzed.The RR of stroke in patients with hypertension was evaluated by CVHP scores.Univariate analysis indicated that hypertension,complicated by other risk factors,had significant statistical association with the onset of stroke.RRS for stroke when hypertension complicated with decrease of hemodynamic scores,heart disease,cigarette smoking and alcohol consumption were 4.93(95%CI,3.26-7.45),1.90(95%CI,1.36-2.66),1.99(95%CI,1.42-2.79)and 1.73(95%CI,1.19-2.53)respectively.In multivariate analysis,hemodynamic score,age,sex,cigarette smoking,family history of stroke and systolic blood pressure were selected by the Cox regression for inclusion in the final analysis.Among them,the RR of hemodynamic score was highest.The analysis of doseresponse relationships indicated that when the hemodynamic scores in patients with hypertension were lower than 75 points,the RR of stroke at 75,60,45,30 and 15 points were 2.85,4.43,4.54,5.40 and 9.88,respectively.The risk of stroke in patients with hypertension is closely associated with hemodynamic impairment and the hemodynamic score may be used for quantitative evaluation of relative risks of stroke.

  17. Disorders of cardiac hemodynamic in attack period of bronchial asthma in children.

    OpenAIRE

    Kondratiev V.А.; Reznyk А.V.

    2016-01-01

    By dopplerechocardiography method there was studied functional state of cardiac ventricles and character of hemodynamic disorders in 48 patients aged 5-17 years in attack period of moderately-severe and severe bronchial asthma. Group of comparison included 40 healthy peers. Disorders of central and peripheral hemodynamic in attack period of bronchial asthma in children were accompanied both by systolic and diastolic dysfunction of the left and right heart ventricles, herewith right ventricle ...

  18. Intrarenal hemodynamics and impaired tubular functions in patients with systemic lupus erythematosus

    OpenAIRE

    A N Maksudova; Liya Aleksandrovna Khusnutdinova; I G Salikhov

    2010-01-01

    Objective. To identify intrarenal hemodynamic disorders in patients with systemic lupus erythematosus (SLE), to assess their prognostic role, and to reveal an association between tubular dysfunction and intraglomerular hemodynamics. Subjects and methods. Twenty-nine SLE patients, 86.2% of them were diagnosed as having a renal lesion, were examined. The levels of ethanolamine, uric acid, calcium, and phosphorus were determined in their daily urine and serum; the renal functional reserve (RF...

  19. Characteristics of Hemodynamic Disorders in Patients with Severe Traumatic Brain Injury

    OpenAIRE

    Rzheutskaya, Ryta E.

    2012-01-01

    Purpose. To define specific features of central hemodynamic parameter changes in patients with isolated severe traumatic brain injury (STBI) and in patients with clinically established brain death and to determine the required course of treatment for their correction. Data and Research Methods. A close study of central hemodynamic parameters was undertaken. The study involved 13 patients with isolated STBI (group STBI) and 15 patients with isolated STBI and clinically established brain death ...

  20. Resting-state hemodynamics are spatiotemporally coupled to synchronized and symmetric neural activity in excitatory neurons.

    Science.gov (United States)

    Ma, Ying; Shaik, Mohammed A; Kozberg, Mariel G; Kim, Sharon H; Portes, Jacob P; Timerman, Dmitriy; Hillman, Elizabeth M C

    2016-12-27

    Brain hemodynamics serve as a proxy for neural activity in a range of noninvasive neuroimaging techniques including functional magnetic resonance imaging (fMRI). In resting-state fMRI, hemodynamic fluctuations have been found to exhibit patterns of bilateral synchrony, with correlated regions inferred to have functional connectivity. However, the relationship between resting-state hemodynamics and underlying neural activity has not been well established, making the neural underpinnings of functional connectivity networks unclear. In this study, neural activity and hemodynamics were recorded simultaneously over the bilateral cortex of awake and anesthetized Thy1-GCaMP mice using wide-field optical mapping. Neural activity was visualized via selective expression of the calcium-sensitive fluorophore GCaMP in layer 2/3 and 5 excitatory neurons. Characteristic patterns of resting-state hemodynamics were accompanied by more rapidly changing bilateral patterns of resting-state neural activity. Spatiotemporal hemodynamics could be modeled by convolving this neural activity with hemodynamic response functions derived through both deconvolution and gamma-variate fitting. Simultaneous imaging and electrophysiology confirmed that Thy1-GCaMP signals are well-predicted by multiunit activity. Neurovascular coupling between resting-state neural activity and hemodynamics was robust and fast in awake animals, whereas coupling in urethane-anesthetized animals was slower, and in some cases included lower-frequency (neural activity. The patterns of bilaterally-symmetric spontaneous neural activity revealed by wide-field Thy1-GCaMP imaging may depict the neural foundation of functional connectivity networks detected in resting-state fMRI.

  1. Concentration-discharge relationships during an extreme event: Contrasting behavior of solutes and changes to chemical quality of dissolved organic material in the Boulder Creek Watershed during the September 2013 flood: SOLUTE FLUX IN A FLOOD EVENT

    Energy Technology Data Exchange (ETDEWEB)

    Rue, Garrett P. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Rock, Nathan D. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Gabor, Rachel S. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA; Pitlick, John [Department of Geography, University of Colorado, Boulder Colorado USA; Tfaily, Malak [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; McKnight, Diane M. [Institute of Arctic and Alpine Research, University of Colorado, Boulder Colorado USA

    2017-07-01

    During the week of September 10-17, 2013, close to 20 inches of rain fell across Boulder County, Colorado, USA. This rainfall represented a 1000-year event that caused massive hillslope erosion, landslides, and mobilization of sediments. The resultant stream flows corresponded to a 100-year flood. For the Boulder Creek Critical Zone Observatory (BC-CZO), this event provided an opportunity to study the effect of extreme rainfall on solute concentration-discharge relationships and biogeochemical catchment processes. We observed base cation and dissolved organic carbon (DOC) concentrations at two sites on Boulder Creek following the recession of peak flow. We also isolated three distinct fractions of dissolved organic matter (DOM) for chemical characterization. At the upper site, which represented the forested mountain catchment, the concentrations of the base cations Ca, Mg and Na were greatest at the peak flood and decreased only slightly, in contrast with DOC and K concentrations, which decreased substantially. At the lower site within urban corridor, all solutes decreased abruptly after the first week of flow recession, with base cation concentrations stabilizing while DOC and K continued to decrease. Additionally, we found significant spatiotemporal trends in the chemical quality of organic matter exported during the flood recession, as measured by fluorescence, 13C-NMR spectroscopy, and FTICR-MS. Similar to the effect of extreme rainfall events in driving landslides and mobilizing sediments, our findings suggest that such events mobilize solutes by the flushing of the deeper layers of the critical zone, and that this flushing regulates terrestrial-aquatic biogeochemical linkages during the flow recession.

  2. The Value of Contrast Echocardiography

    Directory of Open Access Journals (Sweden)

    Shannon C. Treiber

    2016-01-01

    Full Text Available Purpose: There is much evidence-based research proving the effectiveness of contrast echocardiography, but there are still questions and concerns about its specific uses. This study tested the effectiveness of contrast echocardiography in defining the left ventricular endocardial border. Methods: From 30 patients, a total of 60 echocardiograms –– 30 with and 30 without use of contrast –– were retrospectively reviewed by four blinded cardiologists with advanced training in echocardiography. No single cardiologist reviewed contrast and noncontrast images of the same patient. Each set of 30 echocardiograms was then studied for wall-motion scoring. Visualization of left ventricular wall segments and a global visualization confidence level of interpretation were recorded. Results: Of all wall segments (N = 510, 91% were visualized in echocardiograms with use of contrast, whereas 75% of the walls were visualized in echocardiograms without contrast (P < 0.001. Of 30 examinations, 17 contrast echocardiograms were read with high confidence compared to 6 without contrast use (P = 0.004. The number of walls visualized with contrast was increased in 18 patients (60%, whereas noncontrast echocardiograms yielded more visualized walls in 6 patients (20%, P = 0.002. Conclusions: This study demonstrates that contrast is valuable to echocardiographic imaging. Its use should be supported throughout echocardiography clinics and encouraged in certain patients for whom resting and stress echocardiography results without contrast often prove uninterpretable.

  3. Sub-band denoising and spline curve fitting method for hemodynamic measurement in perfusion MRI

    Science.gov (United States)

    Lin, Hong-Dun; Huang, Hsiao-Ling; Hsu, Yuan-Yu; Chen, Chi-Chen; Chen, Ing-Yi; Wu, Liang-Chi; Liu, Ren-Shyan; Lin, Kang-Ping

    2003-05-01

    In clinical research, non-invasive MR perfusion imaging is capable of investigating brain perfusion phenomenon via various hemodynamic measurements, such as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean trasnit time (MTT). These hemodynamic parameters are useful in diagnosing brain disorders such as stroke, infarction and periinfarct ischemia by further semi-quantitative analysis. However, the accuracy of quantitative analysis is usually affected by poor signal-to-noise ratio image quality. In this paper, we propose a hemodynamic measurement method based upon sub-band denoising and spline curve fitting processes to improve image quality for better hemodynamic quantitative analysis results. Ten sets of perfusion MRI data and corresponding PET images were used to validate the performance. For quantitative comparison, we evaluate gray/white matter CBF ratio. As a result, the hemodynamic semi-quantitative analysis result of mean gray to white matter CBF ratio is 2.10 +/- 0.34. The evaluated ratio of brain tissues in perfusion MRI is comparable to PET technique is less than 1-% difference in average. Furthermore, the method features excellent noise reduction and boundary preserving in image processing, and short hemodynamic measurement time.

  4. The effects of hemodynamic lag on functional connectivity and behavior after stroke.

    Science.gov (United States)

    Siegel, Joshua S; Snyder, Abraham Z; Ramsey, Lenny; Shulman, Gordon L; Corbetta, Maurizio

    2016-12-01

    Stroke disrupts the brain's vascular supply, not only within but also outside areas of infarction. We investigated temporal delays (lag) in resting state functional magnetic resonance imaging signals in 130 stroke patients scanned two weeks, three months and 12 months post stroke onset. Thirty controls were scanned twice at an interval of three months. Hemodynamic lag was determined using cross-correlation with the global gray matter signal. Behavioral performance in multiple domains was assessed in all patients. Regional cerebral blood flow and carotid patency were assessed in subsets of the cohort using arterial spin labeling and carotid Doppler ultrasonography. Significant hemodynamic lag was observed in 30% of stroke patients sub-acutely. Approximately 10% of patients showed lag at one-year post-stroke. Hemodynamic lag corresponded to gross aberrancy in functional connectivity measures, performance deficits in multiple domains and local and global perfusion deficits. Correcting for lag partially normalized abnormalities in measured functional connectivity. Yet post-stroke FC-behavior relationships in the motor and attention systems persisted even after hemodynamic delays were corrected. Resting state fMRI can reliably identify areas of hemodynamic delay following stroke. Our data reveal that hemodynamic delay is common sub-acutely, alters functional connectivity, and may be of clinical importance. © The Author(s) 2015.

  5. Influence of population and exercise protocol characteristics on hemodynamic determinants of post-aerobic exercise hypotension

    Directory of Open Access Journals (Sweden)

    L.C. Brito

    2014-08-01

    Full Text Available Due to differences in study populations and protocols, the hemodynamic determinants of post-aerobic exercise hypotension (PAEH are controversial. This review analyzed the factors that might influence PAEH hemodynamic determinants, through a search on PubMed using the following key words: “postexercise” or “post-exercise” combined with “hypotension”, “blood pressure”, “cardiac output”, and “peripheral vascular resistance”, and “aerobic exercise” combined only with “blood pressure”. Forty-seven studies were selected, and the following characteristics were analyzed: age, gender, training status, body mass index status, blood pressure status, exercise intensity, duration and mode (continuous or interval, time of day, and recovery position. Data analysis showed that 1 most postexercise hypotension cases are due to a reduction in systemic vascular resistance; 2 age, body mass index, and blood pressure status influence postexercise hemodynamics, favoring cardiac output decrease in elderly, overweight, and hypertensive subjects; 3 gender and training status do not have an isolated influence; 4 exercise duration, intensity, and mode also do not affect postexercise hemodynamics; 5 time of day might have an influence, but more data are needed; and 6 recovery in the supine position facilitates systemic vascular resistance decrease. In conclusion, many factors may influence postexercise hypotension hemodynamics, and future studies should directly address these specific influences because different combinations may explain the observed variability in postexercise hemodynamic studies.

  6. Slow spontaneous hemodynamic oscillations during sleep measured with near-infrared spectroscopy

    Science.gov (United States)

    Virtanen, Jaakko; Näsi, Tiina; Noponen, Tommi; Toppila, Jussi; Salmi, Tapani; Ilmoniemi, Risto J.

    2011-07-01

    Spontaneous cerebral hemodynamic oscillations below 100 mHz reflect the level of cerebral activity, modulate hemodynamic responses to tasks and stimuli, and may aid in detecting various pathologies of the brain. Near-infrared spectroscopy (NIRS) is ideally suited for both measuring spontaneous hemodynamic oscillations and monitoring sleep, but little research has been performed to combine these two applications. We analyzed 30 all-night NIRS-electroencephalography (EEG) sleep recordings to investigate spontaneous hemodynamic activity relative to sleep stages determined by polysomnography. Signal power of hemodynamic oscillations in the low-frequency (LF, 40-150 mHz) and very-low-frequency (VLF, 3-40 mHz) bands decreased in slow-wave sleep (SWS) compared to light sleep (LS) and rapid-eye-movement (REM) sleep. No statistically significant (p sleep in line with earlier studies with other modalities. These results increase our knowledge of the physiology of sleep, complement EEG data, and demonstrate the applicability of NIRS to studying spontaneous hemodynamic fluctuations during sleep.

  7. Unilateral bicep curl hemodynamics: Low-pressure continuous vs high-pressure intermittent blood flow restriction.

    Science.gov (United States)

    Brandner, C R; Kidgell, D J; Warmington, S A

    2015-12-01

    Light-load exercise training with blood flow restriction (BFR) increases muscle strength and size. However, the hemodynamics of BFR exercise appear elevated compared with non-BFR exercise. This questions the suitability of BFR in special/clinical populations. Nevertheless, hemodynamics of standard prescription protocols for BFR and traditional heavy-load exercise have not been compared. We investigated the hemodynamics of two common BFR exercise methods and two traditional resistance exercises. Twelve young males completed four unilateral elbow flexion exercise trials in a balanced, randomized crossover design: (a) heavy load [HL; 80% one-repetition maximum (1-RM)]; (b) light load (LL; 20% 1-RM); and two other light-load trials with BFR applied (c) continuously at 80% resting systolic blood pressure (BFR-C) or (d) intermittently at 130% resting systolic blood pressure (BFR-I). Hemodynamics were measured at baseline, during exercise, and for 60-min post-exercise. Exercising heart rate, blood pressure, cardiac output, and rate-pressure product were significantly greater for HL and BFR-I compared with LL. The magnitude of hemodynamic stress for BFR-C was between that of HL and LL. These data show reduced hemodynamics for continuous low-pressure BFR exercise compared with intermittent high-pressure BFR in young healthy populations. BFR remains a potentially viable method to improve muscle mass and strength in special/clinical populations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Enhanced External Counterpulsation Inducing Arterial Hemodynamic Variations and Its Chronic Effect on Endothelial Function

    Institute of Scientific and Technical Information of China (English)

    DU Jian-hang; WU Gui-fu; ZHENG Zhen-sheng; DAI Gang; FENG Ming-zhe

    2014-01-01

    To make clear the precise hemodynamic mechanism underlying the anti-atherogenesis benefit of enhanced external couterpulsation(EECP) treatment, and to investigate the proper role of some important hemodynamic factors during the atherosclerotic progress, a comprehensive study combining long-term animal experiment and numerical solving was conducted in this paper. An experimentally induced hypercholesterolemic porcine model was developed and the chronic EECP intervention was subjected. Basic hemodynamic measurement was performed in vivo, as well as the arterial endothelial samples were extracted for physiological examination. Meanwhile, a numerical model was introduced to solve the complex hemodynamic factors such as WSS and OSI. The results show that EECP treatment resulted in significant increase of the instant levels of arterial WSS, blood pressure, and OSI. During EECP treatment, the instant OSI level of the common carotid arteries over cardiac cycles raised to a mean value of 8.58 ×10-2 ±2.13 ×10-2. Meanwhile, the chronic intervention of EECP treatment significantly reduced the atherosclerotic lesions in abdominal aortas and the endothelial cellular adherence. The present study suggests that the unique blood flow pattern induced by EECP treatment and the augmentation of WSS level in cardiac cycles may be the most important hemodynamic mechanism that contribute to its anti-atherogenesis effect. And as one of the indices that cause great concern in current hemodynamic study, OSI may not play a key role during the initiation of atherosclerosis.

  9. Evaluation of Hemodynamic Parameters as Predictors of Glaucoma Progression

    Directory of Open Access Journals (Sweden)

    Ingrida Januleviciene

    2011-01-01

    Full Text Available Purpose. To evaluate hemodynamic parameters as possible predictors for glaucoma progression. Methods. An 18-month randomized double-masked cohort study including 30 open-angle glaucoma patients receiving fixed-combination treatment with Dorzolamide/Timolol (DTFC or Latanoprost/Timolol (LTFC (n=15 per group was performed. Intraocular pressure (IOP, arterial blood pressure (BP, ocular and diastolic perfusion pressures (OPP, DPP, color Doppler imaging, pulsatile ocular blood flow analysis, scanning laser polarimetry, and Humphrey visual field evaluations were included. Results. Both treatments showed statistically similar IOP reduction. Six patients in DTFC and 7 in LTFC group met glaucoma progression criteria. DTFC group had higher OPP, DPP, and lower vascular resistivity indices as compared to the LTFC. Progressing patients had higher nerve fiber index, lower systolic BP, OPP, DPP, higher ophthalmic and central retinal artery vascular resistance, and lower pulse volume (P<.05; t-test. Conclusions. Structural changes consistent with glaucoma progression correlate with non-IOP-dependent risk factors.

  10. Mining data from hemodynamic simulations via Bayesian emulation

    Directory of Open Access Journals (Sweden)

    Nair Prasanth B

    2007-12-01

    Full Text Available Abstract Background: Arterial geometry variability is inevitable both within and across individuals. To ensure realistic prediction of cardiovascular flows, there is a need for efficient numerical methods that can systematically account for geometric uncertainty. Methods and results: A statistical framework based on Bayesian Gaussian process modeling was proposed for mining data generated from computer simulations. The proposed approach was applied to analyze the influence of geometric parameters on hemodynamics in the human carotid artery bifurcation. A parametric model in conjunction with a design of computer experiments strategy was used for generating a set of observational data that contains the maximum wall shear stress values for a range of probable arterial geometries. The dataset was mined via a Bayesian Gaussian process emulator to estimate: (a the influence of key parameters on the output via sensitivity analysis, (b uncertainty in output as a function of uncertainty in input, and (c which settings of the input parameters result in maximum and minimum values of the output. Finally, potential diagnostic indicators were proposed that can be used to aid the assessment of stroke risk for a given patient's geometry.

  11. [The pathophysiology of hemodynamic shock syndrome (part one)].

    Science.gov (United States)

    Kovac, Z; Belina, D

    1998-12-01

    Hemodynamic shock syndrome represents an acute circulatory failure leading to a multiple organ failure. Such circulatory failure develops due to a decrease of arteriovenous blood pressure gradient as a consequence of three independent groups of pathogenic mechanisms (cardiogenic, vasohypotonic and hypovolemic), all of which lead to the common pathogenic pathways. A decrease of arteriovenous pressure gradient induces vasomotoric responses, reactive body fluids redistribution, endocrine, metabolic as well as tissue energy adjustments. In this review a comprehensive synopsis of pathogenic processes is outlined. The cardiogenic mechanisms include the acute systolic and/or diastolic heart failure. Vasohypotonic mechanisms (neurogenic, septic and anaphylactic) are due to vascular tonus missadjustment. Hypovolemia caused by blood, plasma, water and electrolytes losses and/or sequestration, leads to decrease of pressure gradient as soon as the extent of hypovolemia overcomes the compensatory vascular capacity. The decrease of tissue perfusion is direct consequence of the arteriovenous pressure gradient loss. Tissue hypoperfusion causes a progressive depletion of cellular ATP concentration (cellular hypoenergosis), which very often falls lower than 0,1 mmol/L. Cellular hypoenergosis plays the critical role in conversion of negative homeostatic regulation into a positive feedback mode. Positive homeostatic regulation (circuli vitiosi) amplifies deterioration of arteriovenous blood pressure gradient, which reversely intensifies the degree of energy depletion in the tissues. Such homeostatic conversion plays a critical role in the development of progressive phase (systemic failure, decompensation) of the shock.

  12. Tube-Load Model Parameter Estimation for Monitoring Arterial Hemodynamics

    Directory of Open Access Journals (Sweden)

    Guanqun eZhang

    2011-11-01

    Full Text Available A useful model of the arterial system is the uniform, lossless tube with parametric load. This tube-load model is able to account for wave propagation and reflection (unlike lumped-parameter models such as the Windkessel while being defined by only a few parameters (unlike comprehensive distributed-parameter models. As a result, the parameters may be readily estimated by accurate fitting of the model to available arterial pressure and flow waveforms so as to permit improved monitoring of arterial hemodynamics. In this paper, we review tube-load model parameter estimation techniques that have appeared in the literature for monitoring wave reflection, large artery compliance, pulse transit time, and central aortic pressure. We begin by motivating the use of the tube-load model for parameter estimation. We then describe the tube-load model, its assumptions and validity, and approaches for estimating its parameters. We next summarize the various techniques and their experimental results while highlighting their advantages over conventional techniques. We conclude the review by suggesting future research directions and describing potential applications.

  13. Venous hemodynamic changes of lower extremity during gynecological laparoscopy

    Institute of Scientific and Technical Information of China (English)

    YIN Shan-de; LIU Yan; HE Sheng

    2004-01-01

    To study the effect of CO2 pneumoperitoneum and the special 30 degree head-down tilt positionon the venous hemodynamics in the lower extremity. Methods: Color doplex ultrasound was adopted to evaluate the diameterand blood flow velocity of the right femoral vein of 18 patients undergoing gynecologic laparoscopy under the same pressure ofpneumoperitoneum of 12 mmHg. The diameter of femoral vein and the flow velocity were measured; the blood flow volumewas calculated based on the equation of Q = vπr2 . Result: After establishment of pneumoperitoneum, the dilation of the fem-oral vein and the decrease in the velocity and volume can be observed (P < 0.05). And the 30 degree head-down positioncould increase the flow velocity and volume of the femoral vein and decrease the diameter of the vessel ( P < 0.05). At 30minutes of the 30 degree head-down tilt position, the blood flow ameliorated compared with that in prone position after theestablishment of pneumoperitoneum. After deflation of pneumoperitoneum, the femoral vein remained dilated( P < 0.05 ).Conclusion: During laparoscopy, CO2 pneumoperitoneum may result in the dilation of the vein in lower extremity and retar-dance of blood flow. The 30 degree Trendlenburg position can ameliorate the blood flow in the lower extremity. The deflationof the pneumoperitoneum cannot eliminate the effect of CO2 pneumoperitoneum on the lower extremity veins, which may pre-dispose deep venous thrombosis after laparoscopy.

  14. Image based numerical simulation of hemodynamics in a intracranial aneurysm

    Science.gov (United States)

    Le, Trung; Ge, Liang; Sotiropoulos, Fotis; Kallmes, David; Cloft, Harry; Lewis, Debra; Dai, Daying; Ding, Yonghong; Kadirvel, Ramanathan

    2007-11-01

    Image-based numerical simulations of hemodynamics in a intracranial aneurysm are carried out. The numerical solver based on CURVIB (curvilinear grid/immersed boundary method) approach developed in Ge and Sotiropoulos, JCP 2007 is used to simulate the blood flow. A curvilinear grid system that gradually follows the curved geometry of artery wall and consists of approximately 5M grid nodes is constructed as the background grid system and the boundaries of the investigated artery and aneurysm are treated as immersed boundaries. The surface geometry of aneurysm wall is reconstructed from an angiography study of an aneurysm formed on the common carotid artery (CCA) of a rabbit and discretized with triangular meshes. At the inlet a physiological flow waveform is specified and direct numerical simulations are used to simulate the blood flow. Very rich vortical dynamics is observed within the aneurysm area, with a ring like vortex sheds from the proximal side of aneurysm, develops and impinge onto the distal side of the aneurysm as flow develops, and destructs into smaller vortices during later cardiac cycle. This work was supported in part by the University of Minnesota Supercomputing Institute.

  15. Right Ventricular Hemodynamics in Patients with Pulmonary Hypertension

    Science.gov (United States)

    Browning, James; Fenster, Brett; Hertzberg, Jean; Schroeder, Joyce

    2012-11-01

    Recent advances in cardiac magnetic resonance imaging (CMR) have allowed for characterization of blood flow in the right ventricle (RV), including calculation of vorticity and circulation, and qualitative visual assessment of coherent flow patterns. In this study, we investigate qualitative and quantitative differences in right ventricular hemodynamics between subjects with pulmonary hypertension (PH) and normal controls. Fifteen (15) PH subjects and 10 age-matched controls underwent same day 3D time resolved CMR and echocardiography. Echocardiography was used to determine right ventricular diastolic function as well as pulmonary artery systolic pressure (PASP). Velocity vectors, vorticity vectors, and streamlines in the RV were visualized in Paraview and total RV Early (E) and Atrial (A) wave diastolic vorticity was quantified. Visualizations of blood flow in the RV are presented for PH and normal subjects. The hypothesis that PH subjects exhibit different RV vorticity levels than normals during diastole is tested and the relationship between RV vorticity and PASP is explored. The mechanics of RV vortex formation are discussed within the context of pulmonary arterial pressure and right ventricular diastolic function coincident with PH.

  16. Hemodynamic Profiles of Functional and Dysfunctional Forms of Repetitive Thinking.

    Science.gov (United States)

    Ottaviani, Cristina; Brosschot, Jos F; Lonigro, Antonia; Medea, Barbara; Van Diest, Ilse; Thayer, Julian F

    2017-04-01

    The ability of the human brain to escape the here and now (mind wandering) can take functional (problem solving) and dysfunctional (perseverative cognition) routes. Although it has been proposed that only the latter may act as a mediator of the relationship between stress and cardiovascular disease, both functional and dysfunctional forms of repetitive thinking have been associated with blood pressure (BP) reactivity of the same magnitude. However, a similar BP reactivity may be caused by different physiological determinants, which may differ in their risk for cardiovascular pathology. To examine the way (hemodynamic profile) and the extent (compensation deficit) to which total peripheral resistance and cardiac output compensate for each other in determining BP reactivity during functional and dysfunctional types of repetitive thinking. Fifty-six healthy participants randomly underwent a perseverative cognition, a mind wandering, and a problem solving induction, each followed by a 5-min recovery period while their cardiovascular parameters were continuously monitored. Perseverative cognition and problem solving (but not mind wandering) elicited BP increases of similar magnitude. However, perseverative cognition was characterized by a more vascular (versus myocardial) profile compared to mind wandering and problem solving. As a consequence, BP recovery was impaired after perseverative cognition compared to the other two conditions. Given that high vascular resistance and delayed recovery are the hallmarks of hypertension the results suggest a potential mechanism through which perseverative cognition may act as a mediator in the relationship between stress and risk for developing precursors to cardiovascular disease.

  17. Dietary melatonin alters uterine artery hemodynamics in pregnant Holstein heifers.

    Science.gov (United States)

    Brockus, K E; Hart, C G; Gilfeather, C L; Fleming, B O; Lemley, C O

    2016-04-01

    The objective was to examine uterine artery hemodynamics and maternal serum profiles in pregnant heifers supplemented with dietary melatonin (MEL) or no supplementation (CON). In addition, melatonin receptor-mediated responses in steroid metabolism were examined using a bovine endometrial epithelial culture system. Twenty singleton pregnant Holstein heifers were supplemented with 20 mg of melatonin (n = 10) or no melatonin supplementation (control; n = 10) from days 190 to 262 of gestation. Maternal measurements were recorded on days 180 (baseline), 210, 240, and 262 of gestation. Total uterine blood flow was increased by 25% in the MEL-treated heifers compared with the CON. Concentrations of progesterone were decreased in MEL vs CON heifers. Total serum antioxidant capacity was increased by 43% in MEL-treated heifers when compared with CON. Activity of cytochrome P450 1A, 2C, and superoxide dismutase was increased in bovine endometrial epithelial cells treated with melatonin, whereas the melatonin receptor antagonist, luzindole, negated the increase in cytochrome P450 2C activity. Moreover, estradiol or progesterone treatment altered bovine uterine melatonin receptor expression, which could potentiate the melatonin-mediated responses during late gestation. The observed increase in total uterine blood flow during melatonin supplementation could be related to its antioxidant properties. Compromised pregnancies are typically accompanied by increased oxidative stress; therefore, melatonin could serve as a therapeutic supplementation strategy. This could lead to further fetal programming implications in conjunction with offspring growth and development postnatally.

  18. Approximating hemodynamics of cerebral aneurysms with steady flow simulations.

    Science.gov (United States)

    Geers, A J; Larrabide, I; Morales, H G; Frangi, A F

    2014-01-03

    Computational fluid dynamics (CFD) simulations can be employed to gain a better understanding of hemodynamics in cerebral aneurysms and improve diagnosis and treatment. However, introduction of CFD techniques into clinical practice would require faster simulation times. The aim of this study was to evaluate the use of computationally inexpensive steady flow simulations to approximate the aneurysm's wall shear stress (WSS) field. Two experiments were conducted. Experiment 1 compared for two cases the time-averaged (TA), peak systole (PS) and end diastole (ED) WSS field between steady and pulsatile flow simulations. The flow rate waveform imposed at the inlet was varied to account for variations in heart rate, pulsatility index, and TA flow rate. Consistently across all flow rate waveforms, steady flow simulations accurately approximated the TA, but not the PS and ED, WSS field. Following up on experiment 1, experiment 2 tested the result for the TA WSS field in a larger population of 20 cases covering a wide range of aneurysm volumes and shapes. Steady flow simulations approximated the space-averaged WSS with a mean error of 4.3%. WSS fields were locally compared by calculating the absolute error per node of the surface mesh. The coefficient of variation of the root-mean-square error over these nodes was on average 7.1%. In conclusion, steady flow simulations can accurately approximate the TA WSS field of an aneurysm. The fast computation time of 6 min per simulation (on 64 processors) could help facilitate the introduction of CFD into clinical practice.

  19. Bayesian estimation of the hemodynamic response function in functional MRI

    Science.gov (United States)

    Marrelec, G.; Benali, H.; Ciuciu, P.; Poline, J.-B.

    2002-05-01

    Functional MRI (fMRI) is a recent, non-invasive technique allowing for the evolution of brain processes to be dynamically followed in various cognitive or behavioral tasks. In BOLD fMRI, what is actually measured is only indirectly related to neuronal activity through a process that is still under investigation. A convenient way to analyze BOLD fMRI data consists of considering the whole brain as a system characterized by a transfer response function, called the Hemodynamic Response Function (HRF). Precise and robust estimation of the HRF has not been achieved yet: parametric methods tend to be robust but require too strong constraints on the shape of the HRF, whereas non-parametric models are not reliable since the problem is badly conditioned. We therefore propose a full Bayesian, non-parametric method that makes use of basic but relevant a priori knowledge about the underlying physiological process to make robust inference about the HRF. We show that this model is very robust to decreasing signal-to-noise ratio and to the actual noise sampling distribution. We finally apply the method to real data, revealing a wide variety of HRF shapes.

  20. Tube-Load Model Parameter Estimation for Monitoring Arterial Hemodynamics

    Science.gov (United States)

    Zhang, Guanqun; Hahn, Jin-Oh; Mukkamala, Ramakrishna

    2011-01-01

    A useful model of the ar