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Sample records for inadequate tissue perfusion

  1. Plasma acylcarnitines inadequately reflect tissue acylcarnitine metabolism

    NARCIS (Netherlands)

    Schooneman, Marieke G.; Achterkamp, Niki; Argmann, Carmen A.; Soeters, Maarten R.; Houten, Sander M.

    2014-01-01

    Acylcarnitines have been linked to obesity-induced insulin resistance. However the majority of these studies have focused on acylcarnitines in plasma. It is currently unclear to what extent plasma levels of acylcarnitines reflect tissue acylcarnitine metabolism. We investigated the correlation of

  2. Tissue-specific sparse deconvolution for brain CT perfusion.

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    Fang, Ruogu; Jiang, Haodi; Huang, Junzhou

    2015-12-01

    Enhancing perfusion maps in low-dose computed tomography perfusion (CTP) for cerebrovascular disease diagnosis is a challenging task, especially for low-contrast tissue categories where infarct core and ischemic penumbra usually occur. Sparse perfusion deconvolution has been recently proposed to effectively improve the image quality and diagnostic accuracy of low-dose perfusion CT by extracting the complementary information from the high-dose perfusion maps to restore the low-dose using a joint spatio-temporal model. However the low-contrast tissue classes where infarct core and ischemic penumbra are likely to occur in cerebral perfusion CT tend to be over-smoothed, leading to loss of essential biomarkers. In this paper, we propose a tissue-specific sparse deconvolution approach to preserve the subtle perfusion information in the low-contrast tissue classes. We first build tissue-specific dictionaries from segmentations of high-dose perfusion maps using online dictionary learning, and then perform deconvolution-based hemodynamic parameters estimation for block-wise tissue segments on the low-dose CTP data. Extensive validation on clinical datasets of patients with cerebrovascular disease demonstrates the superior performance of our proposed method compared to state-of-art, and potentially improve diagnostic accuracy by increasing the differentiation between normal and ischemic tissues in the brain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effect of Defocused CO2 Laser on Equine Tissue Perfusion

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    Bergh A

    2006-03-01

    Full Text Available Treatment with defocused CO2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differences between clipped and unclipped haircoat were also assessed. Eight horses and two controls received CO2 laser treatment (91 J/cm2 in a randomised order, on a clipped and unclipped area of the hamstring muscles, respectively. The significant increase in clipped skin perfusion and temperature was on average 146.3 ± 33.4 perfusion units (334% and 5.5 ± 1.5°C, respectively. The significant increase in perfusion and temperature in unclipped skin were 80.6 ± 20.4 perfusion units (264% and 4.8 ± 1.4°C. No significant changes were seen in muscle perfusion or temperature. In conclusion, treatment with defocused CO2 laser causes a significant increase in skin perfusion, which is correlated to an increase in skin temperature.

  4. Pathologic evaluation of normal and perfused term placental tissue

    DEFF Research Database (Denmark)

    Maroun, Lisa Leth; Mathiesen, Line; Hedegaard, Morten

    2014-01-01

    with addition of antibiotics to the medium. In the "normal" tissue, certain lesions were very frequent and showed only fair or poor interobserver agreement. Revised minimum criteria for these lesions were defined and found reproducible. This study has emphasized the value of pathologic examination...... and selected findings were tested against success parameters from the perfusions. Finally, the criteria for frequent lesions with fair to poor interobserver variation in the nonperfused tissue were revised and reanalyzed. In the perfused tissue, the perfusion artefact "trophoblastic vacuolization," which...

  5. Blood flow and vascular reactivity in collaterally perfused brain tissue. Evidence of an ischemic penumbra in patients with acute stroke

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    Olsen, T S; Larsen, B; Herning, M

    1983-01-01

    In a group of 48 patients with completed stroke, 8 patients had viable collaterally perfused brain tissue which was accessible for rCBF recordings with a two dimensional technique. All 8 had deep subcortical infarcts on CT-scan, and angiographic occlusion of the arteries normally supplying...... the infarcted territory. The brain tissue overlying the deep infarcts appeared normal on CT-scan and was supplied by collateral circulation. rCBF was measured in all within 72 hours after the stroke. The intra-carotid Xe-133 injection method and a 254 multidetector camera were used to study rCBF. Relatively...... ischemic low flow areas were a constant finding in the collaterally perfused tissue. In 6 of the patients, the collaterally perfused part of the brain had low flow values comparable to those of an "ischemic penumbra" (viable, but functionally depressed brain tissue due to inadequate perfusion...

  6. Phthalate monoesters in perfusate from a dual placenta perfusion system, the placenta tissue and umbilical cord blood

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    Mose, Tina; Mortensen, Gerda K; Hedegaard, Morten

    2006-01-01

    BP), and mono (2-ethyl-hexyl) phthalate (mEHP) were detected in both maternal and fetal perfusate, demonstrating a release of compounds from tissue or blood to perfusates. The distribution of compounds between perfusate, umbilical cord plasma, and tissue was in accordance with the physical-chemical properties...... of the compounds. Results from the present study of compounds residing in the tissue are essential before studying human transplacental transfer, storage, and metabolism of selected phthalate monoesters....

  7. Photoplethysmographic sensors for perfusion measurements in spinal cord tissue

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    Phillips, J P; Kyriacou, P A, E-mail: Justin.Phillips.1@city.ac.uk [School of Engineering and Mathematical Sciences, City University London, EC1V 0HB (United Kingdom)

    2011-08-17

    Sensors for recording photoplethysmographic signals from the nervous tissue of the spinal cord are described. The purpose of these sensors is to establish whether perfusion is compromised in various states of injury which occur in certain animal models of spinal cord injury, for example compression injury. Various measures of perfusion are applicable such as the amplitude of the photoplethysmograph signal and the oxygen saturation, measured using a dual wavelength configuration. Signals are usually compared to baseline measurements made in uninjured subjects. This paper describes two types of probe, one based on optical fibres, and one in which optotes are placed in direct contact with the tissue surface. Results from a study based on a compression model utilising a fibreoptic sensor are presented.

  8. Crossing kingdoms: Using decellularized plants as perfusable tissue engineering scaffolds.

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    Gershlak, Joshua R; Hernandez, Sarah; Fontana, Gianluca; Perreault, Luke R; Hansen, Katrina J; Larson, Sara A; Binder, Bernard Y K; Dolivo, David M; Yang, Tianhong; Dominko, Tanja; Rolle, Marsha W; Weathers, Pamela J; Medina-Bolivar, Fabricio; Cramer, Carole L; Murphy, William L; Gaudette, Glenn R

    2017-05-01

    Despite significant advances in the fabrication of bioengineered scaffolds for tissue engineering, delivery of nutrients in complex engineered human tissues remains a challenge. By taking advantage of the similarities in the vascular structure of plant and animal tissues, we developed decellularized plant tissue as a prevascularized scaffold for tissue engineering applications. Perfusion-based decellularization was modified for different plant species, providing different geometries of scaffolding. After decellularization, plant scaffolds remained patent and able to transport microparticles. Plant scaffolds were recellularized with human endothelial cells that colonized the inner surfaces of plant vasculature. Human mesenchymal stem cells and human pluripotent stem cell derived cardiomyocytes adhered to the outer surfaces of plant scaffolds. Cardiomyocytes demonstrated contractile function and calcium handling capabilities over the course of 21 days. These data demonstrate the potential of decellularized plants as scaffolds for tissue engineering, which could ultimately provide a cost-efficient, "green" technology for regenerating large volume vascularized tissue mass. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Tissue perfusion rate estimation with compression-based photoacoustic-ultrasound imaging

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    Choi, Min; James Shapiro, A. M.; Zemp, Roger

    2018-01-01

    Tissue perfusion is essential for transporting blood oxygen and nutrients. Measurement of tissue perfusion rate would have a significant impact in clinical and preclinical arenas. However, there are few techniques to image this important parameter and they typically require contrast agents. A label-free methodology based on tissue compression and imaging with a high-frequency photoacoustic-ultrasound system is introduced for estimating and visualizing tissue perfusion rates. Experiments demonstrate statistically significant differences in depth-resolved perfusion rates in a human subject with various temperature exposure conditions.

  10. Doppler Monte Carlo simulations of light scattering in tissue to support laser-Doppler perfusion measurements

    NARCIS (Netherlands)

    de Mul, F.F.M.; Steenbergen, Wiendelt; Greve, Jan

    1999-01-01

    Doppler Monte Carlo (DMC) simulations of the transport of light through turbid media, e.g., tissue, can be used to predict or to interpret measurements of the blood perfusion of tissue by laser‐Doppler perfusion flowmetry. We describe the physical and mathematical background of Doppler Monte Carlo

  11. Tissue to plasma capillary permeability of 131I-albumin in the perfused rabbit ear

    DEFF Research Database (Denmark)

    Bent-Hansen, L; Svendsen, Jesper Hastrup

    1991-01-01

    The tissue to plasma transfer of 131I-albumin was recorded in perfused rabbit ears (n = 6) following equilibration for 24 hr. 125I-fibrinogen served as the plasma marker, and was introduced intravenously 15 min before clamping. The ears were rollerpump perfused with isotonic diluted plasma...

  12. In vitro fabrication of functional three-dimensional tissues with perfusable blood vessels.

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    Sekine, Hidekazu; Shimizu, Tatsuya; Sakaguchi, Katsuhisa; Dobashi, Izumi; Wada, Masanori; Yamato, Masayuki; Kobayashi, Eiji; Umezu, Mitsuo; Okano, Teruo

    2013-01-01

    In vitro fabrication of functional vascularized three-dimensional tissues has been a long-standing objective in the field of tissue engineering. Here we report a technique to engineer cardiac tissues with perfusable blood vessels in vitro. Using resected tissue with a connectable artery and vein as a vascular bed, we overlay triple-layer cardiac cell sheets produced from coculture with endothelial cells, and support the tissue construct with media perfused in a bioreactor. We show that endothelial cells connect to capillaries in the vascular bed and form tubular lumens, creating in vitro perfusable blood vessels in the cardiac cell sheets. Thicker engineered tissues can be produced in vitro by overlaying additional triple-layer cell sheets. The vascularized cardiac tissues beat and can be transplanted with blood vessel anastomoses. This technique may create new opportunities for in vitro tissue engineering and has potential therapeutic applications.

  13. Normal Values of Tissue-Muscle Perfusion Indexes of Lower Limbs Obtained with a Scintigraphic Method.

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    Manevska, Nevena; Stojanoski, Sinisa; Pop Gjorceva, Daniela; Todorovska, Lidija; Miladinova, Daniela; Zafirova, Beti

    2017-09-01

    Introduction Muscle perfusion is a physiologic process that can undergo quantitative assessment and thus define the range of normal values of perfusion indexes and perfusion reserve. The investigation of the microcirculation has a crucial role in determining the muscle perfusion. Materials and method The study included 30 examinees, 24-74 years of age, without a history of confirmed peripheral artery disease and all had normal findings on Doppler ultrasonography and pedo-brachial index of lower extremity (PBI). 99mTc-MIBI tissue muscle perfusion scintigraphy of lower limbs evaluates tissue perfusion in resting condition "rest study" and after workload "stress study", through quantitative parameters: Inter-extremity index (for both studies), left thigh/right thigh (LT/RT) left calf/right calf (LC/RC) and perfusion reserve (PR) for both thighs and calves. Results In our investigated group we assessed the normal values of quantitative parameters of perfusion indexes. Indexes ranged for LT/RT in rest study 0.91-1.05, in stress study 0.92-1.04. LC/RC in rest 0.93-1.07 and in stress study 0.93-1.09. The examinees older than 50 years had insignificantly lower perfusion reserve of these parameters compared with those younger than 50, LC (p=0.98), and RC (p=0.6). Conclusion This non-invasive scintigraphic method allows in individuals without peripheral artery disease to determine the range of normal values of muscle perfusion at rest and stress condition and to clinically implement them in evaluation of patients with peripheral artery disease for differentiating patients with normal from those with impaired lower limbs circulation.

  14. Quasi-simultaneous multimodal imaging of cutaneous tissue oxygenation and perfusion

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    Ren, Wenqi; Gan, Qi; Wu, Qiang; Zhang, Shiwu; Xu, Ronald

    2015-12-01

    Simultaneous and quantitative assessment of multiple tissue parameters may facilitate more effective diagnosis and therapy in many clinical applications, such as wound healing. However, existing wound assessment methods are typically subjective and qualitative, with the need for sequential data acquisition and coregistration between modalities, and lack of reliable standards for performance evaluation or calibration. To overcome these limitations, we developed a multimodal imaging system for quasi-simultaneous assessment of cutaneous tissue oxygenation and perfusion in a quantitative and noninvasive fashion. The system integrated multispectral and laser speckle imaging technologies into one experimental setup. Tissue oxygenation and perfusion were reconstructed by advanced algorithms. The accuracy and reliability of the imaging system were quantitatively validated in calibration experiments and a tissue-simulating phantom test. The experimental results were compared with a commercial oxygenation and perfusion monitor. Dynamic detection of cutaneous tissue oxygenation and perfusion was also demonstrated in vivo by a postocclusion reactive hyperemia procedure in a human subject and a wound healing process in a wounded mouse model. Our in vivo experiments not only validated the performance of the multimodal imaging system for cutaneous tissue oxygenation and perfusion imaging but also demonstrated its technical potential for wound healing assessment in clinical practice.

  15. Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study.

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    Young Song

    Full Text Available Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB. We evaluated whether skin perfusion pressure (SPP can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline, during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively. Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI, 0.652-0.963; P = 0.001. Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021 on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

  16. Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study.

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    Song, Young; Soh, Sarah; Shim, Jae-Kwang; Park, Kyoung-Un; Kwak, Young-Lan

    2017-01-01

    Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB). We evaluated whether skin perfusion pressure (SPP) can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline), during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively). Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI), 0.652-0.963; P = 0.001). Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021) on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

  17. Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

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    Strąkowska Maria

    2016-09-01

    Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

  18. The Development of a Thin-Filmed Noninvasive Tissue Perfusion Sensor to Quantify Capillary Pressure Occlusion of Explanted Organs.

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    O'Brien, Timothy J; Roghanizad, Ali R; Jones, Philip A; Aardema, Charles H; Robertson, John L; Diller, Thomas E

    2017-07-01

    A new thin-filmed perfusion sensor was developed using a heat flux gauge, thin-film thermocouple, and a heating element. This sensor, termed "CHFT+," is an enhancement of the previously established combined heat flux-temperature (CHFT) sensor technology predominately used to quantify the severity of burns [1]. The CHFT+ sensor was uniquely designed to measure tissue perfusion on explanted organs destined for transplantation, but could be functionalized and used in a wide variety of other biomedical applications. Exploiting the thin and semiflexible nature of the new CHFT+ sensor assembly, perfusion measurements can be made from the underside of the organ-providing a quantitative indirect measure of capillary pressure occlusion. Results from a live tissue test demonstrated, for the first time, the effects of pressure occlusion on an explanted porcine kidney. CHFT+ sensors were placed on top of and underneath 18 kidneys to measure and compare perfusion at perfusate temperatures of 5 and 20 °C. The data collected show a greater perfusion on the topside than the underside of the specimen for the length of the experiment. This indicates that the pressure occlusion is truly affecting the perfusion, and, thus, the overall preservation of explanted organs. Moreover, the results demonstrate the effect of preservation temperature on the tissue vasculature. Focusing on the topside perfusion only, the 20 °C perfusion was greater than the 5 °C perfusion, likely due to the vasoconstrictive response at the lower perfusion temperatures.

  19. Tissue distribution of cloxacillin after intramammary administration in the isolated perfused bovine udder

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    Niedorf Frank

    2010-10-01

    Full Text Available Abstract Background Various intramammary suspensions containing cloxacillin benzathine are registered for use in cattle as antibiotics for intramammary use at drying off. To ensure antibacterial efficacy, the glandular tissue concentration of an antimicrobial agent must be sufficient. Since the possibilities to measure concentrations in the different areas of the glandular tissue in vivo are very limited, it was the aim of the present study to examine the distribution of cloxacillin in vitro using the isolated perfused bovine udder. Methods Mammary glands taken at slaughter from healthy lactating cows were perfused in vitro with warmed and gassed Tyrode solution. 600 mg cloxacillin benzathine were administered as Orbenin Extra Dry Cow by the intramammary route to six front and rear quarters each. Samples of glandular tissue - at different distances from and vertical to the teat right up to the udder base - were gathered from the treated quarters after 6 h. Perfusate was also sampled before and hourly after treatment for 6 h. The cloxacillin content of the tissue samples and perfusate samples was analysed by high performance liquid chromatography. Results The concentration of cloxacillin in the glandular tissue of front quarters measured 6 h after administration tended to decrease with increasing vertical distance from the teat. The decrease pattern of the concentration was not quite clear in rear quarters. A considerable variation in the tissue concentrations of cloxacillin was obvious, which reflects in vivo conditions. The concentrations measured in the perfusate samples were below the limit of quantification at all time points, indicating limited absorption of the antibiotic from the glandular tissue. Conclusion After intramammary administration of the dry off product containing cloxacillin benzathine concentrations of more than 0.5 μg/g (MIC were reached in all regions of the front and rear quarters.

  20. Drug perfusion enhancement in tissue model by steady streaming induced by oscillating microbubbles.

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    Oh, Jin Sun; Kwon, Yong Seok; Lee, Kyung Ho; Jeong, Woowon; Chung, Sang Kug; Rhee, Kyehan

    2014-01-01

    Drug delivery into neurological tissue is challenging because of the low tissue permeability. Ultrasound incorporating microbubbles has been applied to enhance drug delivery into these tissues, but the effects of a streaming flow by microbubble oscillation on drug perfusion have not been elucidated. In order to clarify the physical effects of steady streaming on drug delivery, an experimental study on dye perfusion into a tissue model was performed using microbubbles excited by acoustic waves. The surface concentration and penetration length of the drug were increased by 12% and 13%, respectively, with streaming flow. The mass of dye perfused into a tissue phantom for 30s was increased by about 20% in the phantom with oscillating bubbles. A computational model that considers fluid structure interaction for streaming flow fields induced by oscillating bubbles was developed, and mass transfer of the drug into the porous tissue model was analyzed. The computed flow fields agreed with the theoretical solutions, and the dye concentration distribution in the tissue agreed well with the experimental data. The computational results showed that steady streaming with a streaming velocity of a few millimeters per second promotes mass transfer into a tissue. © 2013 Published by Elsevier Ltd.

  1. The effect of chair designs on sitting pressure distribution and tissue perfusion.

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    Makhsous, Mohsen; Lin, Fang; Hanawalt, David; Kruger, Shannon Lynn; LaMantia, Angie

    2012-12-01

    The aim of this study was to investigate the effect of five chair designs on interface pressure distribution and tissue perfusion in the buttock-thigh region. Prolonged sitting has been found to contribute to the symptoms of work-related low back pain. Studies have found that chair design affects users' sitting posture and comfort. As sitting applies pressure to the user, it is necessary to investigate how chair design affects sitting pressure and tissue perfusion during sitting. We tested five chair designs (Suspension A, Suspension B, Foam A, Foam B, and bicompliant) on 15 young, healthy females. Sitting interface pressure and buttock-thigh tissue perfusion (in terms oftranscutaneous partial pressure of oxygen and carbon dioxide, tcPO2 and tcPCO2, respectively) were measured during 10-min sitting on each chair. We found that chair design significantly affected the distribution of the sitting pressure (p chair designs, the anterior portion of the seat sustained the lowest contact pressure. It was also found that tcPO2 was the lowest (p chair designs. Chair design and materials of the seat significantly affect the sitting interface pressure distribution and tissue perfusion in sitting area. Further evaluation of these outcomes may provide useful information to correlate chair design with sitting comfort.

  2. A historical perspective on the development of modern concepts of tissue perfusion: prehistory to the twentieth century.

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    Ashby, Nathan; Squiers, Joshua

    2014-09-01

    The historical development of the concept of perfusion is traced, with particular focus on the development of the modern clinical concepts of perfusion through the fields of anatomy, physiology, and biochemistry. This article reviews many of the significant contributors to the changing ideas of perfusion up through the twentieth century that have influenced the modern physiologic circulatory and metabolic models. The developments outlined have provided the modern model of perfusion, linking the cardiopulmonary circulation, tissue oxygen utilization and carbon dioxide production, food intake, tissue waste production and elimination, and ultimately the production and utilization of ATP in the body. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. A Novel Through-Thickness Perfusion Bioreactor for the Generation of Scaffold-Free Tissue Engineered Cartilage

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    Eric Gilbert

    2014-08-01

    Full Text Available The objective of this study was to characterize our designed through-thickness perfusion bioreactor which could generate large scaffold-free tissue engineered cartilage constructs. The hypothesis being that through-thickness perfusion could accelerate maturation of scaffold-free tissue engineered cartilage, grown in transwell culture inserts large enough to repair typical size chondral lesions in the human knee. Internal cell culture media temperature and pH were examined over time, upon implementation of the bioreactor perfusion system inside a CO2 incubator, to ensure adequate regulation conducive to cell viability. Results indicate that temperature and pH both equilibrate within approximately 3 h. The bioreactor was tested for its efficacy to support formation of 4.5 cm2 constructs by porcine neonatal chondrocytes. Tests were conducted under three conditions: immediate perfusion with flow from bottom to top, immediate perfusion with media flow from top to bottom, and bottom to top perfusion after four weeks of static culture, giving the cells time to self-aggregate into a consolidated construct prior to perfusion. The best cell culture results were obtained when perfusion was delayed for four weeks relative to the immediate perfusion of the other methods, and this should be further investigated.

  4. Perfusion decellularization of a human limb: A novel platform for composite tissue engineering and reconstructive surgery.

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    Mattia Francesco Maria Gerli

    Full Text Available Muscle and fasciocutaneous flaps taken from autologous donor sites are currently the most utilized approach for trauma repair, accounting annually for 4.5 million procedures in the US alone. However, the donor tissue size is limited and the complications related to these surgical techniques lead to morbidities, often involving the donor sites. Alternatively, recent reports indicated that extracellular matrix (ECM scaffolds boost the regenerative potential of the injured site, as shown in a small cohort of volumetric muscle loss patients. Perfusion decellularization is a bioengineering technology that allows the generation of clinical-scale ECM scaffolds with preserved complex architecture and with an intact vascular template, from a variety of donor organs and tissues. We recently reported that this technology is amenable to generate full composite tissue scaffolds from rat and non-human primate limbs. Translating this platform to human extremities could substantially benefit soft tissue and volumetric muscle loss patients providing tissue- and species-specific grafts. In this proof-of-concept study, we show the successful generation a large-scale, acellular composite tissue scaffold from a full cadaveric human upper extremity. This construct retained its morphological architecture and perfusable vascular conduits. Histological and biochemical validation confirmed the successful removal of nuclear and cellular components, and highlighted the preservation of the native extracellular matrix components. Our results indicate that perfusion decellularization can be applied to produce human composite tissue acellular scaffolds. With its preserved structure and vascular template, these biocompatible constructs, could have significant advantages over the currently implanted matrices by means of nutrient distribution, size-scalability and immunological response.

  5. [CT perfusion imaging evaluation on hemodynamic changes of acute spontaneous intracerebral hemorrhage surrounding tissues].

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    Kuang, Yi; Chen, Weijian; Zheng, Kuikui; Fu, Jun; Hu, Zilong; Yang, Yunjun; Dai, Yichuan

    2015-11-17

    To discuss the hemodynamic changes in patients with acute supratentorial spontaneous intracerebral hemorrhage (within 72 hours) by using 320-slice of low-dose volume CT perfusion imaging. Twenty-six patients of The First Affiliated Hospital of Wenzhou Medical University during December 2012 to December 2013 with acute supratentorial SICH diagnosed by plain CT scanning and clinic were enrolled. With hematoma maximum level for reference, the hematoma volume, edema area and perfusion defect area were measured, and the perfusion parameters values of the marginal area and outer area of the intracerebral hematoma and contralateral mirror area were measured, including cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time-to-peak (TTP), and rCBF, rCBV, rMTT and rTTP were calculated by ipsilateral/contralateral value. The CBF, CBV of the marginal area were lower than the contralateral mirror area (tCBF=-8.125, tCBV=-8.671, PCBF, CBVperfusion defect area showed a positive linear relation with the volume of acute hematoma (r=0.440, Pperfusion defect area (r=0.400, r=0.81, PCT perfusion imaging can perfectly reflect the hemodynamic changes in brain tissuse after acute supratentorial SICH. Hypoperfusion was appeared in perihematomal area of acute supratentorial SICH. The perihematomal brain tissue may exists ischemic injury associated with the size of hematoma.The hematoma place holder effect, ischemic injury are the important cause of acute brain edema formation.

  6. Establishing Early Functional Perfusion and Structure in Tissue Engineered Cardiac Constructs

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    Wang, Bo; Patnaik, Sourav S.; Brazile, Bryn; Butler, J. Ryan; Claude, Andrew; Zhang, Ge; Guan, Jianjun; Hong, Yi; Liao, Jun

    2016-01-01

    Myocardial infarction (MI) causes massive heart muscle death and remains a leading cause of death in the world. Cardiac tissue engineering aims to replace the infarcted tissues with functional engineered heart muscles or revitalize the infarcted heart by delivering cells, bioactive factors, and/or biomaterials. One major challenge of cardiac tissue engineering and regeneration is the establishment of functional perfusion and structure to achieve timely angiogenesis and effective vascularization, which are essential to the survival of thick implants and the integration of repaired tissue with host heart. In this paper, we review four major approaches to promoting angiogenesis and vascularization in cardiac tissue engineering and regeneration: delivery of pro-angiogenic factors/molecules, direct cell implantation/cell sheet grafting, fabrication of prevascularized cardiac constructs, and the use of bioreactors to promote angiogenesis and vascularization. We further provide a detailed review and discussion on the early perfusion design in nature-derived biomaterials, synthetic biodegradable polymers, tissue-derived acellular scaffolds/whole hearts, and hydrogel derived from extracellular matrix. A better understanding of the current approaches and their advantages, limitations, and hurdles could be useful for developing better materials for future clinical applications. PMID:27480586

  7. Extracellular Matrix Hydrogel Promotes Tissue Remodeling, Arteriogenesis, and Perfusion in a Rat Hindlimb Ischemia Model

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    Jessica L. Ungerleider, BS

    2016-01-01

    Full Text Available Although surgical and endovascular revascularization can be performed in peripheral arterial disease (PAD, 40% of patients with critical limb ischemia do not have a revascularization option. This study examines the efficacy and mechanisms of action of acellular extracellular matrix-based hydrogels as a potential novel therapy for treating PAD. We tested the efficacy of using a tissue-specific injectable hydrogel derived from decellularized porcine skeletal muscle (SKM and compared this to a new human umbilical cord-derived matrix (hUC hydrogel, which could have greater potential for tissue regeneration because of the younger age of the tissue source. In a rodent hindlimb ischemia model, both hydrogels were injected 1-week post-surgery and perfusion was regularly monitored with laser speckle contrast analysis to 35 days post-injection. There were significant improvements in hindlimb tissue perfusion and perfusion kinetics with both biomaterials. Histologic analysis indicated that the injected hydrogels were biocompatible, and resulted in arteriogenesis, rather than angiogenesis, as well as improved recruitment of skeletal muscle progenitors. Skeletal muscle fiber morphology analysis indicated that the muscle treated with the tissue-specific SKM hydrogel more closely matched healthy tissue morphology. Whole transcriptome analysis indicated that the SKM hydrogel caused a shift in the inflammatory response, decreased cell death, and increased blood vessel and muscle development. These results show the efficacy of an injectable ECM hydrogel alone as a potential therapy for treating patients with PAD. Our results indicate that the SKM hydrogel improved functional outcomes through stimulation of arteriogenesis and muscle progenitor cell recruitment.

  8. Automated prediction of tissue outcome after acute ischemic stroke in computed tomography perfusion images

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    Vos, Pieter C.; Bennink, Edwin; de Jong, Hugo; Velthuis, Birgitta K.; Viergever, Max A.; Dankbaar, Jan Willem

    2015-03-01

    Assessment of the extent of cerebral damage on admission in patients with acute ischemic stroke could play an important role in treatment decision making. Computed tomography perfusion (CTP) imaging can be used to determine the extent of damage. However, clinical application is hindered by differences among vendors and used methodology. As a result, threshold based methods and visual assessment of CTP images has not yet shown to be useful in treatment decision making and predicting clinical outcome. Preliminary results in MR studies have shown the benefit of using supervised classifiers for predicting tissue outcome, but this has not been demonstrated for CTP. We present a novel method for the automatic prediction of tissue outcome by combining multi-parametric CTP images into a tissue outcome probability map. A supervised classification scheme was developed to extract absolute and relative perfusion values from processed CTP images that are summarized by a trained classifier into a likelihood of infarction. Training was performed using follow-up CT scans of 20 acute stroke patients with complete recanalization of the vessel that was occluded on admission. Infarcted regions were annotated by expert neuroradiologists. Multiple classifiers were evaluated in a leave-one-patient-out strategy for their discriminating performance using receiver operating characteristic (ROC) statistics. Results showed that a RandomForest classifier performed optimally with an area under the ROC of 0.90 for discriminating infarct tissue. The obtained results are an improvement over existing thresholding methods and are in line with results found in literature where MR perfusion was used.

  9. Comparative analysis of lower extremities tissue perfusion by the use of perfusion scintigraphy method after hyperbaric oxygenation and lumbar sympathectomy

    Directory of Open Access Journals (Sweden)

    Zoranović Uroš

    2009-01-01

    Full Text Available Background/Aim. Lumbar syphatectomy (LS increases pheripheral blood flow primarily by the arteriolar vasodilatation within the skin vascular net. Increase in tissue nutrition takes place only in the distal blood vessels of the skin. Nevertheless, in some patients sympathectomy brings about improvement in ischemic ulcerations healing. Hyperbaric oxigenation (HBO is a medical treatment in which a patient breathes 100% oxygen under pressure higher than atmospheric implemented in special units allowing the whole body be in a chamber. The aim of the study was to determine efficacy of the applied therapies for the treatment of inoperable occlusive lower extremities (LE arteries diseases according to the obtained results. Methods. The study included 30 patients divided into two groups (15 patients each in which stenosis level of the lower extremities arteries had been determined using aortography due to further treatment with HBO and LS. All the patients were clinically examined, their objective condition evaluation based on claudication distance, pain in rest, skin and skin adnexa atrophy, and temperature and LE functionality, as well as exposed to perfusion scintigraphy prior to the treatment and within 30 days after the treatment finishing. Results. Analyzing patients' status prior to and after the treatments applied the number of patients with obvious improvement was higher in those treated by HBO than those treated by LS. Measuring claudication distance revealed significantly greater changes in patients treated by HBO (from 178.57 m to 754.76 m than in those treated by LS (from 229 m to 253 m. Other clinical symptoms, such as parasthesia, status of the skin adnexes (hair, nails, skin colour and temperature were also improved after the treatment by HBO. Conclusion. The results obatined in this study confirm the advantages of HBO over LS in therapy of inoperable occlusive LE disease, so LS could be definitely abandoned as a choice for treating such

  10. RPE in perfusion tissue culture and its response to laser application. Preliminary report.

    Science.gov (United States)

    Framme, Carsten; Kobuch, Karin; Eckert, Elfriede; Monzer, Jan; Roider, Johann

    2002-01-01

    To study the effects of conventional laser application on the retinal pigment epithelium (RPE) in a perfusion tissue culture model of porcine retinal pigment epithelium without overlying neurosensory retina. RPE with underlying choroid was prepared from enucleated porcine eyes and fixed in a holding ring (Minusheet). Specimens were then placed in two-compartment tissue culture containers (MinuCell & Minutissue, Bad Abbach, Germany) and were cultured during continuous perfusion with culture medium at both sides of the entire specimen, the upper RPE and the lower choroid (12 specimens out of 6 eyes). Cultures were kept for 1, 3, 7 and 14 days and were examined histologically. Laser treatment was performed on each tissue ring by application of 3 x 3 laser burns one day after culture began (argon ion laser, wavelength: 514 nm, pulse duration: 100 ms; spot size: 200 microm) using different energy levels (400-1,000 mW); (16 specimens out of 8 eyes). During laser treatment a marked lightening of the RPE with centrifugal spreading was observed. Using higher levels of energy, a contraction of the RPE towards the center of the laser spot was noticed. One day after laser photocoagulation histology revealed destruction of RPE; within 3-7 days of culture, migration and proliferation of neighboring cells was observed in several lesions. After 7 days the initial defect of the irradiated area was covered with dome shaped RPE cells and after 14 days multilayered RPE cells were showing ongoing proliferation. However, there were also cases without proliferation after laser treatment. The non-treated, continuously perfused RPE showed regular appearance in histological sections: during the first 7 days of culture, light microscopy revealed a normal matrix with a well-differentiated RPE monolayer. Subsequently proliferation even without treatment was observed and after 14 days the RPE became multilayered. It was possible to study the early healing response to the effect of laser

  11. 3D printing of microtube in solid phantom to simulate tissue oxygenation and perfusion (Conference Presentation)

    Science.gov (United States)

    Lv, Xiang; Xue, Yue; Wang, Haili; Shen, Shu Wei; Zhou, Ximing; Liu, Guangli; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    Tissue-simulating phantoms with interior vascular network may facilitate traceable calibration and quantitative validation of many medical optical devices. However, a solid phantom that reliably simulates tissue oxygenation and blood perfusion is still not available. This paper presents a new method to fabricate hollow microtubes for blood vessel simulation in solid phantoms. The fabrication process combines ultraviolet (UV) rapid prototyping technique with fluid mechanics of a coaxial jet flow. Polydimethylsiloxane (PDMS) and a UV-curable polymer are mixed at the designated ratio and extruded through a coaxial needle device to produce a coaxial jet flow. The extruded jet flow is quickly photo-polymerized by ultraviolet (UV) light to form vessel-simulating solid structures at different sizes ranging from 700 μm to 1000 μm. Microtube structures with adequate mechanical properties can be fabricated by adjusting material compositions and illumination intensity. Curved, straight and stretched microtubes can be formed by adjusting the extrusion speed of the materials and the speed of the 3D printing platform. To simulate vascular structures in biologic tissue, we embed vessel-simulating microtubes in a gel wax phantom of 10 cm x10 cm x 5 cm at the depth from 1 to 2 mm. Bloods at different oxygenation and hemoglobin concentration levels are circulated through the microtubes at different flow rates in order to simulate different oxygenation and perfusion conditions. The simulated physiologic parameters are detected by a tissue oximeter and a laser speckle blood flow meter respectively and compared with the actual values. Our experiments demonstrate that the proposed 3D printing process is able to produce solid phantoms with simulated vascular networks for potential applications in medical device calibration and drug delivery studies.

  12. Increases in microvascular perfusion and tissue oxygenation via pulsed electromagnetic fields in the healthy rat brain.

    Science.gov (United States)

    Bragin, Denis E; Statom, Gloria L; Hagberg, Sean; Nemoto, Edwin M

    2015-05-01

    High-frequency pulsed electromagnetic field stimulation is an emerging noninvasive therapy being used clinically to facilitate bone and cutaneous wound healing. Although the mechanisms of action of pulsed electromagnetic fields (PEMF) are unknown, some studies suggest that its effects are mediated by increased nitric oxide (NO), a well-known vasodilator. The authors hypothesized that in the brain, PEMF increase NO, which induces vasodilation, enhances microvascular perfusion and tissue oxygenation, and may be a useful adjunct therapy in stroke and traumatic brain injury. To test this hypothesis, they studied the effect of PEMF on a healthy rat brain with and without NO synthase (NOS) inhibition. In vivo two-photon laser scanning microscopy (2PLSM) was used on the parietal cortex of rat brains to measure microvascular tone and red blood cell (RBC) flow velocity in microvessels with diameters ranging from 3 to 50 μm, which includes capillaries, arterioles, and venules. Tissue oxygenation (reduced nicotinamide adenine dinucleotide [NADH] fluorescence) was also measured before and for 3 hours after PEMF treatment using the FDA-cleared SofPulse device (Ivivi Health Sciences, LLC). To test NO involvement, the NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) was intravenously injected (10 mg/kg). In a time control group, PEMF were not used. Doppler flux (0.8-mm probe diameter), brain and rectal temperatures, arterial blood pressure, blood gases, hematocrit, and electrolytes were monitored. Pulsed electromagnetic field stimulation significantly dilated cerebral arterioles from a baseline average diameter of 26.4 ± 0.84 μm to 29.1 ± 0.91 μm (11 rats, p PEMF-induced changes in arteriolar diameter, microvascular perfusion, and tissue oxygenation (7 rats). No changes in measured parameters were observed throughout the study in the untreated time controls (5 rats). This is the first demonstration of the acute effects of PEMF on cerebral cortical microvascular

  13. Prostaglandin E2 formation by rat gastroduodenal tissue following intragastric acid perfusion.

    Science.gov (United States)

    Kapicioglu, S; McNamara, D B; Vacarella, M Y; Kadowitz, P J; Hoda, S; Ertan, A

    1990-04-01

    Rat gastroduodenal mucosa forms prostaglandin (PG) E2. However, little is known about regional differences in PGE2 formation or the effect of gastric hydrochloric acid (HC1) perfusion on regional PGE2 formation. In this study, the rats were divided into 3 groups. Group 1 received intravenous (i.v.), 1 Ml/h, and intragastric (i.g.), 8 ml/h, perfusions of saline simultaneously for 3 h. Group 2 received saline i.v. and 0.15 N HC1 i.g., 8 ml/h. Group 3 was injected with a bolus of asprin (ASA), 60 mg/kg, followed by ASA, 40 mg/kg/h i.v., and 0.15 N HC1 i.g.. The gastric aspirates were analyzed for volume and pH. Segments of gastroduodenal tissue from the fundus, corpus, antrum, and duodenum were minced and then incubated in 1 ml of 5 mM Tris buffer, pH 8.4, for 30 sec with mixing; the incubate was assayed for PGE2 by radioimmunoassay. Intragastric HC1 decreased the pH of aspirate without producing gastric mucosal lesions. However, when combined with i.v. ASA, ulcer formation was present in all animals (p less than 0.05). PGE2 was formed by isolated tissue from four different gastroduodenal regions. The duodenum formed significantly greater amounts than the fundus, antrum, or corpus, which were similar. Intragastric HC1 produced a trend toward increased PGE2 formation (pmol PGE2/mg tissue) in the fundus, 143 +/- 36 to 237 +/- 57; corpus, 87 +/- 13 to 200 +/- 57; antrum, 157 +/- 28 to 224 +/- 65; and duodenum, 235 +/- 56 to 338 +/- 51. However, statistical significance was not reached.

  14. Correction of disorders in tissue perfusion, blood coagulation and fibrinolysis with Orbita apparatus on terahertz waves of cell metabolites

    Directory of Open Access Journals (Sweden)

    Vyacheslav F. Kirichuk

    2013-02-01

    Full Text Available This article contains information on principle of operation, technical parameters and possible application of Orbita {transliteration from Russian} apparatus for hemodynamic, fibrinolytic and peripheral perfusion disorders treatment. A single exposure to terahertz waves emitted by Orbita apparatus, corresponding to frequencies of molecular absorption and emission spectra of atmospheric oxygen (129.0 GHz, completely cures coagulant and fibrinolytic disorders of animals with acute immobilization stress. A course of treatment with electromagnetic waves corresponding to frequencies of molecular absorption and emission spectra of nitrogen oxide (150.176 – 150.664 leads to normalization of disrupted peripheral tissue perfusion parameters of animal undergoing treatment and stimulates basal and induced output of nitrogen oxide. This leads to decrease in peripheral vascular resistance to microcirculation and increase in blood flow to microvasculature. Experimental data provided in this article serves as a proof of viability of Orbita apparatus for treatment of coagulant, fibrinolytic and tissue perfusion disorders.

  15. Defining Characteristics and Related Factors of Decreased Cardiac Tissue Perfusion: Proposal of a New Nursing Diagnosis.

    Science.gov (United States)

    Santos, Vinicius Batista; Atallah, Álvaro Nagib; Lopes, Camila Takáo; Lopes, Juliana de Lima; Bottura Leite de Barros, Alba Lúcia

    2016-07-01

    To identify the possible defining characteristics (DCs) and related factors of the nursing diagnosis (ND) decreased cardiac tissue perfusion. Cross-sectional study using medical charts of adults admitted to an emergency department with the chief complaint of chest pain in a hospital in São Paulo, Brazil. DCs identified: crushing chest pain, elevated markers of myocardial necrosis, ischemic electrocardiogram changes, sweating, nausea, and vomiting. Related factors identified: interruption of arterial blood flow and coronary spasm. This ND was clinically identified due to significant differences in the DCs of patients with and without the diagnosis. The clinical indicators identified in this study can be the starting point for the DCs for this ND. © 2015 NANDA International, Inc.

  16. Determination of the transport of thermal energy by conduction in perfused tissue

    International Nuclear Information System (INIS)

    Waterman, F.M.; Tupchong, L.; Matthews, J.; Nerlinger, R.E.

    1987-01-01

    A limitation of the thermal clearance method for determination of the blood flow rate during local hyperthermia is its inability to distinguish between thermal energy transport by perfusion and thermal conduction. A method is described for determination of the thermal energy transport by conduction at the point where thermal clearance is measured. Three profiles of the tissue temperature are measured in mutually orthogonal directions about this point. The conduction term of the bioheat equation is evaluated from the temperature profiles by the method of finite differences. The ability to determine the rate of thermal energy transport by conduction from orthogonal temperature profiles is demonstrated in a static phantom where conduction is the only mode of thermal energy transport. The implementation of this method in the clinic is described

  17. Targeted tissue perfusion versus macrocirculation-guided standard care in patients with septic shock (TARTARE-2S)

    DEFF Research Database (Denmark)

    Pettilä, Ville; Merz, Tobias; Wilkman, Erika

    2016-01-01

    at least 200 patients with septic shock in four European intensive care units (ICUs) to test whether a tissue perfusion-guided treatment strategy based on capillary refill time, peripheral temperature, arterial lactate concentrations, and accepting lower MAP levels, leads to a faster resolution of shock...

  18. Does a Better Perfusion of Deconditioned Muscle Tissue Release Chronic Low Back Pain?

    Directory of Open Access Journals (Sweden)

    Paola Valdivieso

    2018-03-01

    Full Text Available Non-specific chronic low back pain (nsCLBP is a multifactorial condition of unknown etiology and pathogenesis. Physical and genetic factors may influence the predisposition of individuals to CLBP, which in many instances share a musculoskeletal origin. A reduced pain level in low back pain patients that participate in exercise therapy highlights that disuse-related muscle deconditioning may predispose individuals to nsCLBP. In this context, musculoskeletal pain may be the consequence of capillary rarefaction in inactive muscle as this would lower local tissue drainage and washing out of toxic waste. Muscle activity is translated into an angio-adaptative process, which implicates angiogenic-gene expression and individual response differences due to heritable modifications of such genes (gene polymorphisms. The pathophysiologic mechanism underlying nsCLBP is still largely unaddressed. We hypothesize that capillary rarefaction due to a deconditioning of dorsal muscle groups exacerbates nsCLBP by increasing noxious sensation, reducing muscle strength and fatigue resistance by initiating a downward spiral of local deconditioning of back muscles which diminishes their load-bearing capacity. We address the idea that specific factors such as angiotensin-converting enzyme and Tenascin-C might play an important role in altering susceptibility to nsCLBP via their effects on microvascular perfusion and vascular remodeling of skeletal muscle, inflammation, and pain sensation. The genetic profile may help to explain the individual predisposition to nsCLBP, thus identifying subgroups of patients, which could benefit from ad hoc treatment types. Future therapeutic approaches aimed at relieving the pain associated with nsCLBP should be based on the verification of mechanistic processes of activity-induced angio-adaptation and muscle-perfusion.

  19. Comparative study of rabbit VX2 hepatic implantation tumor and normal liver tissue on magnetic resonance perfusion weighted imaging

    International Nuclear Information System (INIS)

    Jiao Zimei; Wang Xizhen; Wang Bin; Liu Feng; Li Haiqing; Sun Yequan; Dong Peng

    2012-01-01

    Objective: To investigate the value of magnetic resonance (MR) perfusion weighted imaging (PWI) in evaluating the blood perfusion of tumor by analyzing the features and indexes of PWI on rabbit VX2 hepatic implantation tumor and normal liver tissue. Methods: Twenty-four New Zealand White rabbits with VX2 carcinoma were established under direct surgical vision embedding tumor tissue. MR examination was performed at 21 days after the tumor implantation. The signal intensity -time curve of hepatic tumor and normal liver tissue were obtained. Mean time to enhance (MTE), negative enhancement integral (NEI), time to minimum (TM), maximum slope of decrease (MSD) and maximum slope of increase (MSI) were measured. Results: MTE, NEI, TM, MSD, and MSI of the normal liver tissue were 208.341±2.226 ms, 78.334±8.152, 24.059±1.927 ms, 38.221±2.443, and 15.389±2.526, respectively. MTE, NEI, TM, MSD, and MSI of the tumor tissue were 175.437±4.182 ms, 123.203±19.455, 17.061±1.834 ms, 125.740±4.842, and 67.832±2.882, respectively. The MTE and TM of tumor were shorter than those of normal hepatic tissue (P<0.05). NEI, MSD, and MSI of tumor were higher than those of normal hepatic tissue (P<0.05). Conclusion: PWI can distinguish the normal liver tissue from the tumor tissue, which is helpful in evaluating blood perfusion of different hepatic tissues. (authors)

  20. Tissue to plasma capillary permeability of 131I-albumin in the perfused rabbit ear

    DEFF Research Database (Denmark)

    Bent-Hansen, L; Svendsen, Jesper Hastrup

    1991-01-01

    was marked, and occurred at rates corresponding to a unidirectional clearance (Cl(0)) of 0.068 +/- 0.012 ml (min.100 g)-1. However, with a reduction of mean interstitial albumin tracer content of no more than 4%, net transport decreased to reach slowly declining levels 5 to 10 times lower within 10 min...... at a constant rate of (mean +/- SD) 5.1 +/- 1.5 ml (min.100 g)-1. The mean extravascular albumin distribution volume was 12.4 +/- 1.1 ml.100 g-1, and the fibrinogen volume (plasma volume in tissue) was 3.1 +/- 0.4 ml.100 g-1 as determined from biopsies of the contralateral ear. The initial transfer of albumin...... of continued perfusion. The decrease was considered due to rapid exhaustion of a small interstitial pool of tracer immediately adjacent to the exchange vessel membrane, followed by an increasingly retarded outwash from more distant areas. The results suggest a bimodal structural resistance to albumin movement...

  1. Repair of segmental bone defect using Totally Vitalized tissue engineered bone graft by a combined perfusion seeding and culture system.

    Directory of Open Access Journals (Sweden)

    Lin Wang

    Full Text Available BACKGROUND: The basic strategy to construct tissue engineered bone graft (TEBG is to combine osteoblastic cells with three dimensional (3D scaffold. Based on this strategy, we proposed the "Totally Vitalized TEBG" (TV-TEBG which was characterized by abundant and homogenously distributed cells with enhanced cell proliferation and differentiation and further investigated its biological performance in repairing segmental bone defect. METHODS: In this study, we constructed the TV-TEBG with the combination of customized flow perfusion seeding/culture system and β-tricalcium phosphate (β-TCP scaffold fabricated by Rapid Prototyping (RP technique. We systemically compared three kinds of TEBG constructed by perfusion seeding and perfusion culture (PSPC method, static seeding and perfusion culture (SSPC method, and static seeding and static culture (SSSC method for their in vitro performance and bone defect healing efficacy with a rabbit model. RESULTS: Our study has demonstrated that TEBG constructed by PSPC method exhibited better biological properties with higher daily D-glucose consumption, increased cell proliferation and differentiation, and better cell distribution, indicating the successful construction of TV-TEBG. After implanted into rabbit radius defects for 12 weeks, PSPC group exerted higher X-ray score close to autograft, much greater mechanical property evidenced by the biomechanical testing and significantly higher new bone formation as shown by histological analysis compared with the other two groups, and eventually obtained favorable healing efficacy of the segmental bone defect that was the closest to autograft transplantation. CONCLUSION: This study demonstrated the feasibility of TV-TEBG construction with combination of perfusion seeding, perfusion culture and RP technique which exerted excellent biological properties. The application of TV-TEBG may become a preferred candidate for segmental bone defect repair in orthopedic and

  2. DIEP flap customization using Fluobeam® indocyanine green tissue perfusion assessment with large previous abdominal scar

    Directory of Open Access Journals (Sweden)

    Michael A. Fallucco

    2017-06-01

    Full Text Available The Fluobeam® is a portable, near-infrared camera that is held and controlled by the surgeon to visualize tissue perfusion using indocyanine green (ICG fluorescence imaging. This case report describes how data obtained from ICG imaging allows intraoperative customization in a previously surgically scarred abdomen during autologous Deep Inferior Epigastric Artery Perforator (DIEP flap bilateral breast reconstruction. The outcome was successful breast mound recreation without fat necrosis.

  3. Detecting the subregion proceeding to infarction in hypoperfused cerebral tissue: a study with diffusion and perfusion weighted MRI

    International Nuclear Information System (INIS)

    Liu, Y.; Vanninen, R.L.; Vainio, P.A.; Soimakallio, S.; Karonen, J.O.; Nuutinen, J.; Perkioe, J.; Aronen, H.J.

    2003-01-01

    Diffusion and perfusion weighted MRI have been widely used in ischaemic stroke. We studied 17 patients in whom ischaemic areas showed an ischaemic core, an area of infarct growth and hypoperfused but ultimately surviving tissue. Apparent diffusion coefficients (ADC) were measured on days 1, 2, and 8 in the three subregions and in contralateral control areas. Cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were measured in these regions on day 1 perfusion maps. On day 1, the ischaemic core had very low ADC and CBF and increased MTT. The ADC in the ischaemic core gradually increased during the week. The area of infarct growth on day 1 had slightly but significantly decreased ADC (96% of control, P=0.028), moderately decreased CBF and increased MTT. On day 1 the hypoperfused but surviving tissue had slightly but significantly increased ADC (103% of control, P=0.001), mildly decreased CBF and increased CBV and MTT. The ADC of the area of infarct growth decreased to the same level as in the ischaemic core on days 2 and 8. That of surviving tissue was still above normal on day 2 (103% of control), but had returned to the normal level by day 8. Measurement of ADC combined with perfusion MRI may help distinguish different subregions in acutely hypoperfused brain. (orig.)

  4. Hepatic Differentiation of Human Induced Pluripotent Stem Cells in a Perfused 3D Porous Polymer Scaffold for Liver Tissue Engineering

    DEFF Research Database (Denmark)

    Hemmingsen, Mette; Muhammad, Haseena Bashir; Mohanty, Soumyaranjan

    A huge shortage of liver organs for transplantation has motivated the research field of tissue engineering to develop bioartificial liver tissue and even a whole liver. The goal of NanoBio4Trans is to create a vascularized bioartificial liver tissue, initially as a liver-support system. Due...... to limitations of primary hepatocytes regarding availability and maintenance of functionality, stem cells and especially human induced pluripotent stem cells (hIPS cells) are an attractive cell source for liver tissue engineering. The aim of this part of NanoBio4Trans is to optimize culture and hepatic...... differentiation of hIPS-derived definitive endoderm (DE) cells in a 3D porous polymer scaffold built-in a perfusable bioreactor. The use of a microfluidic bioreactor array enables the culture of 16 independent tissues in one experimental run and thereby an optimization study to be performed....

  5. Post-operative monitoring of tissue transfers: advantages using contrast enhanced ultrasound (CEUS) and contrast enhanced MRI (ceMRI) with dynamic perfusion analysis?

    Science.gov (United States)

    Lamby, P; Prantl, L; Fellner, C; Geis, S; Jung, E M

    2011-01-01

    The immediate evaluation of microvascular tissue flaps with respect to microcirculation after transplantation is crucial for optimal monitoring and outcome. The purpose of our investigation was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced MRI (ceMRI) for monitoring the integrity of tissue flaps in plastic surgery. To this end, we investigated 10 patients (47 ± 16 a) between postoperative day 7 and 14 who underwent flap surgery in order to cover tissue defects in various body regions. For CEUS we utilized the GE LOGIQ E9 equipped with a linear transducer (6-9 MHz). After application of 2.4 ml SonoVue, the tissue perfusion was detected in Low MI-Technique (MI present, both technologies provide an optimal assessment of perfusion in cutaneous, subcutaneous and muscle tissue layers, whereby the detection of fatty tissue perfusion is currently more easily detected using CEUS compared to ceMRI.

  6. Effect of nicorandil on the myocardial tissue perfusion and myocardial cell injury in patients with diabetes after PCI

    Directory of Open Access Journals (Sweden)

    Xue-Li Ren1

    2017-04-01

    Full Text Available Objective: To study the effect of nicorandil on the myocardial tissue perfusion and myocardial cell damage in patients with diabetes after percutaneous coronary intervention (PCI. Methods: 68 patients with coronary heart disease and type 2 diabetes mellitus who received PCI in our hospital between May 2011 and September 2015 were collected and then divided into observation group and control group (n=34 according to the single-blind randomized control method. Control group of patients received PCI alone, and the observation group of patients received nicorandil therapy after PCI. After treatment, real-time myocardial ultrasound contrast was used to evaluate the myocardial perfusion of two groups of patients; blood biochemical analyzer was used to detect the contents of peripheral blood myocardial enzyme spectrum indexes; the ELISA method was used to detect the contents of serum oxidative stress indicators; RIA method was used to detect the contents of serum apoptosis molecules. Results: After treatment, the myocardial tissue perfusion parameters plateau peak intensity (A, slope rate of curve (β and myocardial blood flow (A×β levels of observation group were significantly higher than those of control group (P<0.05; peripheral blood myocardial enzyme spectrum indexes creatine kinase (CK, lactate dehydrogenase (LDH, troponin I (cTnI and glutamic oxalacetic transaminase (GOT contents of observation group were significantly lower than those of control group (P<0.05; serum vitamin E (VitE and vitamin C (VitC contents of observation group were significantly higher than those of control group while malondialdehyde (MDA, advanced oxidation protein products (AOPPs, soluble apoptosis-associated factor (sFas and soluble apoptosis-associated factor ligand (sFasL contents were lower than those of control group (P<0.05. Conclusion: Adjuvant nicorandil therapy can improve the myocardial perfusion and reduce the myocardial cell injury in patients with coronary

  7. The effect of laser power, blood perfusion, thermal and optical properties of human liver tissue on thermal damage in LITT.

    Science.gov (United States)

    Shibib, Khalid Salem; Munshid, Mohammed A; Lateef, Hind Ali

    2017-12-01

    In this work, the finite-element method (FEM) was used to predict the temperature distribution, and the thermal damage volume in human liver tissue subjected to laser in laser-induced interstitial thermotherapy (LITT). The effect of laser power, blood perfusion, and thermal and optical properties on maximum temperature and thermal damage volume were predicted using the finite-element method. A computer program was written in visual basic language, which was verified by comparing its result with data published elsewhere. The bio-heat equation together with the effect of linear laser source were used to simulate heat transfer through tissue from which the temperature distributions, and the subsequent thermal damage, were obtained based on Arrhenius equation. In this mathematical model for LITT, it was found that increasing laser power, absorption, and scattering coefficient increased the damage zone while increasing tissue water content, perfusion rate, and tissue anisotropy factor decreased the damage zone. These findings are important aspects for doctors in the pre-estimation of the damage zone before starting the therapy so as to kill only the desired zone.

  8. Review of temperature dependence of thermal properties, dielectric properties, and perfusion of biological tissues at hyperthermic and ablation temperatures.

    Science.gov (United States)

    Rossmanna, Christian; Haemmerich, Dieter

    2014-01-01

    The application of supraphysiological temperatures (>40°C) to biological tissues causes changes at the molecular, cellular, and structural level, with corresponding changes in tissue function and in thermal, mechanical and dielectric tissue properties. This is particularly relevant for image-guided thermal treatments (e.g. hyperthermia and thermal ablation) delivering heat via focused ultrasound (FUS), radiofrequency (RF), microwave (MW), or laser energy; temperature induced changes in tissue properties are of relevance in relation to predicting tissue temperature profile, monitoring during treatment, and evaluation of treatment results. This paper presents a literature survey of temperature dependence of electrical (electrical conductivity, resistivity, permittivity) and thermal tissue properties (thermal conductivity, specific heat, diffusivity). Data of soft tissues (liver, prostate, muscle, kidney, uterus, collagen, myocardium and spleen) for temperatures between 5 to 90°C, and dielectric properties in the frequency range between 460 kHz and 3 GHz are reported. Furthermore, perfusion changes in tumors including carcinomas, sarcomas, rhabdomyosarcoma, adenocarcinoma and ependymoblastoma in response to hyperthmic temperatures up to 46°C are presented. Where appropriate, mathematical models to describe temperature dependence of properties are presented. The presented data is valuable for mathematical models that predict tissue temperature during thermal therapies (e.g. hyperthermia or thermal ablation), as well as for applications related to prediction and monitoring of temperature induced tissue changes.

  9. An automated method for analysis of microcirculation videos for accurate assessment of tissue perfusion

    Directory of Open Access Journals (Sweden)

    Demir Sumeyra U

    2012-12-01

    Full Text Available Abstract Background Imaging of the human microcirculation in real-time has the potential to detect injuries and illnesses that disturb the microcirculation at earlier stages and may improve the efficacy of resuscitation. Despite advanced imaging techniques to monitor the microcirculation, there are currently no tools for the near real-time analysis of the videos produced by these imaging systems. An automated system tool that can extract microvasculature information and monitor changes in tissue perfusion quantitatively might be invaluable as a diagnostic and therapeutic endpoint for resuscitation. Methods The experimental algorithm automatically extracts microvascular network and quantitatively measures changes in the microcirculation. There are two main parts in the algorithm: video processing and vessel segmentation. Microcirculatory videos are first stabilized in a video processing step to remove motion artifacts. In the vessel segmentation process, the microvascular network is extracted using multiple level thresholding and pixel verification techniques. Threshold levels are selected using histogram information of a set of training video recordings. Pixel-by-pixel differences are calculated throughout the frames to identify active blood vessels and capillaries with flow. Results Sublingual microcirculatory videos are recorded from anesthetized swine at baseline and during hemorrhage using a hand-held Side-stream Dark Field (SDF imaging device to track changes in the microvasculature during hemorrhage. Automatically segmented vessels in the recordings are analyzed visually and the functional capillary density (FCD values calculated by the algorithm are compared for both health baseline and hemorrhagic conditions. These results were compared to independently made FCD measurements using a well-known semi-automated method. Results of the fully automated algorithm demonstrated a significant decrease of FCD values. Similar, but more variable FCD

  10. Perfusion-based three dimensional (3D) tissue engineering platform with integrated bioimpedance sensing

    DEFF Research Database (Denmark)

    Muhammad, Haseena Bashir; Canali, Chiara; Heiskanen, Arto

    2014-01-01

    We present an 8-channel bioreactor array with integrated bioimpedance sensors, which enables perfusion culture of cells seeded onto porous 3D scaffolds. Results show the capability of the system for monitoring cell proliferation within the scaffolds through a culture period of 19 days....

  11. Contrast-enhanced, real-time volumetric ultrasound imaging of tissue perfusion: preliminary results in a rabbit model of testicular torsion

    Science.gov (United States)

    Paltiel, H. J.; Padua, H. M.; Gargollo, P. C.; Cannon, G. M., Jr.; Alomari, A. I.; Yu, R.; Clement, G. T.

    2011-04-01

    Contrast-enhanced ultrasound (US) imaging is potentially applicable to the clinical investigation of a wide variety of perfusion disorders. Quantitative analysis of perfusion is not widely performed, and is limited by the fact that data are acquired from a single tissue plane, a situation that is unlikely to accurately reflect global perfusion. Real-time perfusion information from a tissue volume in an experimental rabbit model of testicular torsion was obtained with a two-dimensional matrix phased array US transducer. Contrast-enhanced imaging was performed in 20 rabbits during intravenous infusion of the microbubble contrast agent Definity® before and after unilateral testicular torsion and contralateral orchiopexy. The degree of torsion was 0° in 4 (sham surgery), 180° in 4, 360° in 4, 540° in 4, and 720° in 4. An automated technique was developed to analyze the time history of US image intensity in experimental and control testes. Comparison of mean US intensity rate of change and of ratios between mean US intensity rate of change in experimental and control testes demonstrated good correlation with testicular perfusion and mean perfusion ratios obtained with radiolabeled microspheres, an accepted 'gold standard'. This method is of potential utility in the clinical evaluation of testicular and other organ perfusion.

  12. Adhesion of Plasmodium falciparum infected erythrocytes in ex vivo perfused placental tissue

    DEFF Research Database (Denmark)

    Pehrson, Caroline; Mathiesen, Line; Heno, Kristine K

    2016-01-01

    , such as binding to immunoglobulins. Furthermore, other parasite antigens have been associated with placental malaria. These findings have important implications for placental malaria vaccine design. The objective of this study was to adapt and describe a biologically relevant model of parasite adhesion in intact...... expressing VAR2CSA accumulated in perfused placental tissue whereas the EPCR binding and the transgenic parasite did not. Soluble CSA and antibodies specific against VAR2CSA inhibited binding of infected erythrocytes. CONCLUSION: The ex vivo model provides a novel way of studying receptor-ligand interactions...

  13. Lack of histological cerebellar changes in Wistar rats given pulegone for 28 days. Comparison of immersion and perfusion tissue fixation

    DEFF Research Database (Denmark)

    Mølck, Anne-Marie; Poulsen, Morten; Lauridsen, Søren Tindgard

    1998-01-01

    Pulegone was given orally by gavage to groups of 28 SPF Wistar rats at dosage levels of 0 or 160 mg/kg body weight per day for 28 days. Clinically treated animals showed slackness, depression, decreased food consumption, and body weight. The loss of body weight was accompanied by a marked decrease...... in plasma creatinine. In contrast to earlier results, this study did not reveal occurrence of cyst-like spaces in the white matter of cerebellum using either perfusion or immersion tissue fixation techniques. Pulegone increased plasma alkaline phosphatase and relative liver weight indicating an adverse...

  14. The comparative study of MR perfusion-weighted imaging and 1H-MR spectroscopy in diagnosing soft tissue tumors

    International Nuclear Information System (INIS)

    Zhang Li'na; Wang Shaowu; Song Qingwei; Sun Meiyu

    2008-01-01

    Objective: To evaluate multiple magnetic resonance (MR) imaging techniques in the differentiation of benign and malignant soft tissue tumors by comparing different information from MR perfusion-weighted Imaging (MR-PWI) and 1 HMR spectroscopy ( 1 H-MRS). Methods: Forty patients with soft tissue tumors underwent conventional MR imaging, dynamic contrast-enhanced T 2 * -weighted MR-PWI and 1 H proton MR spectroscopy. The differences of perfusion and 1 H-MRS parameters of benign and malignant tumors were analyzed with t test. Results: There was significant difference between benign and malignant tumoral tissues of BF value and Cho/Cr ratio (t=2.531, 2.927, P -1 ·min -1 , sensitivity and specificity for determining malignant tumors were 81.8% (18/22), 72.2% (13/18), respectively. When the threshold value of Cho/Cr ratio was 3.22, Sensitivity and specificity for determining malignant tumors were 86.4% (19/22), 88.9% (16/18), respectively. The abnormal wave crest is detected at 2.0-2.1 ppm in 5 malignant tumors (2 malignant schwannoma and 3 malignant fibrous histiocytoma), while the other 55 cases were not. Conclusion: The BF value and Cho/Cr ratio were both valuable diagnostic parameters in differentiating benign and malignant soft tissue tumors. TIC was helpful to distinguish malignant tumors from benign tumors, while the sensitivity and specificity of 1 H-MRS in diagnosing malignant soft tissue tumors were both higher. (authors)

  15. Compact dual-mode diffuse optical system for blood perfusion monitoring in a porcine model of microvascular tissue flaps

    Science.gov (United States)

    Lee, Seung Yup; Pakela, Julia M.; Helton, Michael C.; Vishwanath, Karthik; Chung, Yooree G.; Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Christian, James F.; O'Reilly, Jameson; Farkas, Dana; Ward, Brent B.; Feinberg, Stephen E.; Mycek, Mary-Ann

    2017-12-01

    In reconstructive surgery, the ability to detect blood flow interruptions to grafted tissue represents a critical step in preventing postsurgical complications. We have developed and pilot tested a compact, fiber-based device that combines two complimentary modalities-diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy-to quantitatively monitor blood perfusion. We present a proof-of-concept study on an in vivo porcine model (n=8). With a controllable arterial blood flow supply, occlusion studies (n=4) were performed on surgically isolated free flaps while the device simultaneously monitored blood flow through the supplying artery as well as flap perfusion from three orientations: the distal side of the flap and two transdermal channels. Further studies featuring long-term monitoring, arterial failure simulations, and venous failure simulations were performed on flaps that had undergone an anastomosis procedure (n=4). Additionally, benchtop verification of the DCS system was performed on liquid flow phantoms. Data revealed relationships between diffuse optical measures and state of occlusion as well as the ability to detect arterial and venous compromise. The compact construction of the device, along with its noninvasive and quantitative nature, would make this technology suitable for clinical translation.

  16. MRI tissue perfusion quantification : MR sequence optimization and inflow effect correction

    OpenAIRE

    Ivancevic, Marko K.

    2003-01-01

    Le sujet de cette thèse est la mesure de perfusion tissulaire par l'IRM et injection du produit de contraste. Les principes d'IRM, la méthodologie, les différentes séquences d'imagerie rapide, et les produits de contraste sont d'abord passés en revue. Dans la première partie, l'optimisation des paramètres de séquences d'écho de gradient pour la dynamique de contraste et conversion du signal en concentration de contraste est présentée. Ensuite, l'effet de flux sanguin sur l'intensité de signal...

  17. MRI tissue perfusion quantification: MR sequence optimization and inflow effect correction

    OpenAIRE

    Ivancevic, Marko K; Descouts, Pierre; Vallée, Jean-Paul

    2004-01-01

    Le sujet de cette thèse est la mesure de perfusion tissulaire par l'IRM et injection du produit de contraste. Les principes d'IRM, la méthodologie, les différentes séquences d'imagerie rapide, et les produits de contraste sont d'abord passés en revue. Dans la première partie, l'optimisation des paramètres de séquences d'écho de gradient pour la dynamique de contraste et conversion du signal en concentration de contraste est présentée. Ensuite, l'effet de flux sanguin sur l'intensité de signal...

  18. Improved repair of bone defects with prevascularized tissue-engineered bones constructed in a perfusion bioreactor.

    Science.gov (United States)

    Li, De-Qiang; Li, Ming; Liu, Pei-Lai; Zhang, Yuan-Kai; Lu, Jian-Xi; Li, Jian-Min

    2014-10-01

    Vascularization of tissue-engineered bones is critical to achieving satisfactory repair of bone defects. The authors investigated the use of prevascularized tissue-engineered bone for repairing bone defects. The new bone was greater in the prevascularized group than in the non-vascularized group, indicating that prevascularized tissue-engineered bone improves the repair of bone defects. [Orthopedics. 2014; 37(10):685-690.]. Copyright 2014, SLACK Incorporated.

  19. Isolated limb perfusion with tumor necrosis factor alpha and melphalan for locally advanced soft tissue sarcoma : Three time periods at risk for amputation

    NARCIS (Netherlands)

    van Ginkel, Robert J.; Thijssens, Katja M. J.; Pras, Elisabeth; van der Graaf, Winette T. A.; Suurmeijer, Albert J. H.; Hoekstra, Harald J.

    Background: The aim of this study was to investigate the long-term limb salvage rate and overall survival after isolated limb perfusion (ILP) with tumor necrosis factor alpha and melphalan for locally advanced soft tissue sarcoma (STS). Methods: From 1991 to 2003, 73 patients (36 men, 37 women,

  20. Isolated limb perfusion with tumor necrosis factor alpha and melphalan for locally advanced soft tissue sarcoma: three time periods at risk for amputation.

    NARCIS (Netherlands)

    Ginkel, R.J. van; Thijssens, K.M.; Pras, E.; Graaf, W.T.A. van der; Suurmeijer, A.J.H.; Hoekstra, H.J.

    2007-01-01

    BACKGROUND: The aim of this study was to investigate the long-term limb salvage rate and overall survival after isolated limb perfusion (ILP) with tumor necrosis factor alpha and melphalan for locally advanced soft tissue sarcoma (STS). METHODS: From 1991 to 2003, 73 patients (36 men, 37 women,

  1. Non-contact tissue perfusion and oxygenation imaging using a LED based multispectral and a thermal imaging system, first results of clinical intervention studies

    NARCIS (Netherlands)

    Klaessens, J.H.G.M.; Nelisse, M.; Verdaasdonk, R.M.; Noordmans, H.J.

    2013-01-01

    During clinical interventions objective and quantitative information of the tissue perfusion, oxygenation or temperature can be useful for the surgical strategy. Local (point) measurements give limited information and affected areas can easily be missed, therefore imaging large areas is required. In

  2. Re-thinking resuscitation: Leaving blood pressure cosmetics behind and moving forward to permissive hypotension and a tissue perfusion-based approach

    NARCIS (Netherlands)

    M.W. Dünser (Martin); E.P. Takala; A. Brunauer (Andreas); J. Bakker (Jan)

    2013-01-01

    textabstractDefinitions of shock and resuscitation endpoints traditionally focus on blood pressures and cardiac output. This carries a high risk of overemphasizing systemic hemodynamics at the cost of tissue perfusion. In line with novel shock definitions and evidence of the lack of a correlation

  3. Chlorine and sodium perfusion and electrolyte balance in human tissue and tumours before and during neutron and photon radiotherapy

    Science.gov (United States)

    Koester, L.; Knopf, K.; Auberger, Th

    1997-08-01

    Radiotherapy with nuclear reactor fission neutrons was applied in 49 cases of pre-treated patients with superficial metastases or relapses from primary carcinoma. Measurements of the decay rates of the radiation-induced radioactivity of , and in the irradiated tissue resulted in values for the simultaneous local kinetics of chlorine and sodium, and in approximate data on the electrolyte masses. The electrolytes were present in non-exchangeable and exchangeable compartments of soft tissue. Exchange times of the intravascular to extravascular turnover and the frequencies of the exchange fractions were determined for a series of irradiations. The results have been interpreted in terms of the mean electrolyte exchange rates, of a standardized functional blood flow, and of the supply capacity of the vascular system. In the average of all cases, the regional perfusion was reduced by about 30% by irradiation up to 14 Gy (equivalent photon dose ) connected with an increase in the non-exchangeable fractions. After fractionated doses higher than 14 Gy, functional blood flow and supply capacity increased to 120%, and fixed electrolytes were removed from the irradiated tissue. Data on electrolyte kinetics and vascularity are compared with the literature.

  4. Tissue-engineered vessel strengthens quickly under physiological deformation: application of a new perfusion bioreactor with machine vision.

    Science.gov (United States)

    Xu, Jie; Ge, Haiyan; Zhou, Xiaolin; Yang, Daping; Guo, Tiefang; He, Jian; Li, Qing; Hao, Zhenhong

    2005-01-01

    In order to develop a patent tissue-engineered blood vessel that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. For the sake of shortening the maturation period of the constructs, we have used deformation as the basic index for mechanical environment control. A new bioreactor with a machine vision identifier was developed to accurately control the deformation of the construct during the perfusion process. Two groups of seeded constructs (n = 4 per group) were investigated in this study, with one group stimulated by a cyclic deformation of 10% and the other by a pulsatile pressure that gradually increased to 120 mm Hg (the control group). After 21 days of culture, the mechanical properties of the constructs were examined. The average burst strength and suture retention strength in the two groups were significantly different (t test, p < 0.05). For the experimental group, the average burst strength and suture retention strength were higher than those of the control group, by 31.6 and 23.4%, respectively. Specifically, the average burst strength of the constructs reached 1,402 mm Hg (close to that of the native vessel, i.e. 1,680 mm Hg) within a relatively short period of 21 days. In conclusion, deformation is an observable, controllable and very valuable index for mechanical environment control in vascular tissue engineering. It makes the control of mechanical stimuli more essential and experiments more comparable.

  5. The comparative study of MR diffusion-weighted imaging and MR perfusion-weighted imaging in diagnosing soft tissue tumors

    International Nuclear Information System (INIS)

    Wang Shaowu; Zhang Li'na; Sun Meiyu; Song Qingwei; Jia Feige

    2009-01-01

    Objective: To evaluate MR diffusion-weighted imaging (DWI)and MR perfusion- weighted imaging(PWI) in differentiating benign from malignant soft tissue tumors by comparing the related parameters. Methods: Fifty patients with soft tissue tumors verified by pathology (benign 24, malignant 26) underwent DWI and dynamic contrast-enhanced T 2 * -weighted PWI. DWI and PWI data of benign and malignant soft tissue tumors were acquired at the workstation and their difference was analyzed with t-test. The diagnostic accordance rate was verified with x 2 -test. Subjective overall performance of two techniques were evaluated with receiver operating characteristic (ROC) analysis. Results: ADC values of benign and malignant tumors were (2.03±0.36) x 10 -3 mm 2 /s, (1.52±0.39) x 10 -3 mm 2 /s, respectively. The signal intensity decrease of them during the first-pass perfusion (SI decrease ) were (13.54 ± 3.37)%, (47.57 ± 5.21)%, respectively. The maximum linearity slope rate of TIC (SS max ) of them were (5.51 ± 2.54)%, (7.94 ± 3.33)%, respectively. There were significant differences between benign and malignant tumors of ADC value and SI decrease (t=2.515, 2.938; P max (t= 1.272,P>0.05). When the threshold of ADC value was 1.866 x mm 2 /s, sensitivity and specificity for determining malignant tumors were 84.6% (22/26)and 83.3% (20/24). When the threshold of SI decrease was 40.33%, sensitivity and specificity for determining malignant tumors were 88.5% (23/26)and 75.0% (18/24). In type la of TIC, the proportion of benign soft tissue tumor was 3/24 and malignant tumor was 20/26. In type Ib, benign tumor was 14/24 and malignant tumor was 3/26. In type Ic, malignant tumor was 3/26. In type II, benign tumor was 7/24. The diagnostic accordance rate of DWI and PWI were 84.0% (42/50)and 82.0% (41/50), respectively. There was no significant difference between them (χ 2 =0.8, P>0.05). The accuracies of them were 81.7%, 83.6% respectively by the area under the ROC curve (AUC). The

  6. Non-invasive estimation of hepatic blood perfusion from H{sub 2} {sup 15}O PET images using tissue-derived arterial and portal input functions

    Energy Technology Data Exchange (ETDEWEB)

    Kudomi, N.; Slimani, L.; Jaervisalo, M.J.; Lautamaeki, R.; Naum, G.A.; Knuuti, J. [University of Turku, Turku PET Centre (Finland); Kiss, J.; Savunen, T. [University of Turku, Department on Surgery, Turku (Finland); Iida, H. [National Cardiovascular Center-Research Institute, Department of Investigative Radiology, Advanced Medical-Engineering Center, Suita, Osaka (Japan); Nuutila, P. [University of Turku, Turku PET Centre (Finland); University of Turku, Department of Medicine, Turku (Finland); Iozzo, P. [University of Turku, Turku PET Centre (Finland); National Research Council, Institute of Clinical Physiology, Pisa (Italy)

    2008-10-15

    The liver is perfused through the portal vein and the hepatic artery. When its perfusion is assessed using positron emission tomography (PET) and {sup 15}O-labeled water (H{sub 2}{sup 15}O), calculations require a dual blood input function (DIF), i.e., arterial and portal blood activity curves. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not feasible in humans. The aim of the present study was to develop a new technique to estimate quantitative liver perfusion from H{sub 2}{sup 15}O PET images with a completely non-invasive approach. We studied normal pigs (n=14) in which arterial and portal blood tracer concentrations and Doppler ultrasonography flow rates were determined invasively to serve as reference measurements. Our technique consisted of using model DIF to create tissue model function and the latter method to simultaneously fit multiple liver time-activity curves from images. The parameters obtained reproduced the DIF. Simulation studies were performed to examine the magnitude of potential biases in the flow values and to optimize the extraction of multiple tissue curves from the image. The simulation showed that the error associated with assumed parameters was <10%, and the optimal number of tissue curves was between 10 and 20. The estimated DIFs were well reproduced against the measured ones. In addition, the calculated liver perfusion values were not different between the methods and showed a tight correlation (r=0.90). In conclusion, our results demonstrate that DIF can be estimated directly from tissue curves obtained through H{sub 2}{sup 15}O PET imaging. This suggests the possibility to enable completely non-invasive technique to assess liver perfusion in patho-physiological studies. (orig.)

  7. Perfusion bioreactor-based cryopreservation of 3D human mesenchymal stromal cell tissue grafts

    Czech Academy of Sciences Publication Activity Database

    Petrenko, Yuriy; Petrenko, A.; Martin, I.; Wendt, D.

    2017-01-01

    Roč. 76, jun. (2017), s. 150-153 ISSN 0011-2240 Institutional support: RVO:68378041 Keywords : cryopreservation * tissue engineering * mesenchymal stromal cells Subject RIV: FP - Other Medical Disciplines OBOR OECD: Cell biology Impact factor: 1.996, year: 2016

  8. Inadequate housing in Ghana

    Directory of Open Access Journals (Sweden)

    Franklin Obeng-Odoom

    2011-01-01

    Full Text Available Two themes are evident in housing research in Ghana. One involves the study of how to increase the number of dwellings to correct the overall housing deficit, and the other focuses on how to improve housing for slum dwellers. Between these two extremes, there is relatively little research on why the existing buildings are poorly maintained. This paper is based on a review of existing studies on inadequate housing. It synthesises the evidence on the possible reasons for this neglect, makes a case for better maintenance and analyses possible ways of reversing the problem of inadequate housing.

  9. Non-invasive estimation of hepatic blood perfusion from H215O PET images using tissue-derived arterial and portal input functions

    International Nuclear Information System (INIS)

    Kudomi, N.; Slimani, L.; Jaervisalo, M.J.; Lautamaeki, R.; Naum, G.A.; Knuuti, J.; Kiss, J.; Savunen, T.; Iida, H.; Nuutila, P.; Iozzo, P.

    2008-01-01

    The liver is perfused through the portal vein and the hepatic artery. When its perfusion is assessed using positron emission tomography (PET) and 15 O-labeled water (H 2 15 O), calculations require a dual blood input function (DIF), i.e., arterial and portal blood activity curves. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not feasible in humans. The aim of the present study was to develop a new technique to estimate quantitative liver perfusion from H 2 15 O PET images with a completely non-invasive approach. We studied normal pigs (n=14) in which arterial and portal blood tracer concentrations and Doppler ultrasonography flow rates were determined invasively to serve as reference measurements. Our technique consisted of using model DIF to create tissue model function and the latter method to simultaneously fit multiple liver time-activity curves from images. The parameters obtained reproduced the DIF. Simulation studies were performed to examine the magnitude of potential biases in the flow values and to optimize the extraction of multiple tissue curves from the image. The simulation showed that the error associated with assumed parameters was 2 15 O PET imaging. This suggests the possibility to enable completely non-invasive technique to assess liver perfusion in patho-physiological studies. (orig.)

  10. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  11. The Elusive Path of Brain Tissue Oxygenation and Cerebral Perfusion in Harness Hang Syncope in Mountain Climbers.

    Science.gov (United States)

    Lanfranconi, Francesca; Pollastri, Luca; Corna, Giovanni; Bartesaghi, Manuela; Novarina, Massimiliano; Ferri, Alessandra; Miserocchi, Giuseppe Andrea

    2017-12-01

    Lanfranconi, Francesca, Luca Pollastri, Giovanni Corna, Manuela Bartesaghi, Massimiliano Novarina, Alessandra Ferri, and Giuseppe Andrea Miserocchi. The elusive path of brain tissue oxygenation and cerebral perfusion in harness hang syncope in mountain climbers. High Alt Med Biol. 18:363-371, 2017. Harness hang syncope (HHS) is a risk that specifically affects wide ranges of situations requiring safety harnesses in mountains. An irreversible orthostatic stasis could lead to death if a prompt rescue is not performed. We aimed at evaluating the risk of developing HHS and at identifying the characteristics related to the pathogenesis of HHS. Forty adults (aged 39.1 [8.2] years) were enrolled in a suspension test lasting about 28.7 (11.4) minutes. We measured cardiovascular parameters, and near infrared spectroscopy (NIRS) was used to assess cerebral hypoxia by changes in the concentration of oxyhemoglobin (Δ[HbO 2 ]) and de-oxyhemoglobin (Δ[HHb]). In the four participants who developed HHS: (1) systolic and diastolic blood pressure showed ample oscillations with a final abrupt drop (∼30 mmHg); (2) Δ[HbO 2 ] increased after 8-12 minutes of suspension and reached a plateau before HHS; and (3) Δ[HHb] decreased with a final abrupt increase before syncope. Participants who developed HHS failed to activate cardiovascular reflexes that usually safeguard O 2 availability to match the metabolic needs of the brain tissue. Since cerebral hypoxia was detected as an early phenomenon by Δ[HbO 2 ] and Δ[HHb] changes, NIRS measurement appears to be the most important parameter to monitor the onset of HHS.

  12. Direct assessment of lipoprotein outflow from in vivo-labeled arterial tissue as determined in an in vitro perfusion system.

    Science.gov (United States)

    Björnheden, T; Bondjers, G; Wiklund, O

    1998-12-01

    The rate of cholesterol deposition during the atherosclerotic process is determined by the balance between the inflow and outflow of plasma lipoproteins in the arterial wall. Whereas the rate of inflow may be measured directly, the rate of outflow has most often been calculated indirectly from lipoprotein uptake by using the 2-compartment model. One objection against such calculations is that lipoprotein binding is not being considered. In the present study 2 different protocols were used to obtain a direct measure of the outflow of lipoproteins from atherosclerotic rabbit aortas. Thus, 3 rabbits with experimental atherosclerosis were given 125I-LDL intravenously and 3 were given [14C]cholesterol perorally. Twenty-four hours later the aortas were removed and the outflow of label was monitored during in vitro perfusion. Despite the different protocols, our results were consistent and indicated that fractional loss relative to whole tissue was approximately 0.01 pool/h, which is 1 order of magnitude lower than current estimates based on the 2-compartment model (0.04 to 0.4 pool/h). Furthermore, whereas as much as 2/3 to 3/4 of the tracer that had entered the arterial wall was effectively trapped, the remainder equilibrated at a faster rate (0.06 pool/h). In conclusion, it seems that tissue binding constitutes a prominent and possibly underrated mechanism of lipoprotein deposition, at least in the atherosclerotic rabbit aorta. Furthermore, this means that current estimates of lipoprotein exchange parameters based on the 2-compartment model (eg, fractional loss) may rest on invalid assumptions and should be regarded with caution.

  13. Macro- and microelements in the rat liver, kidneys, and brain tissues; sex differences and effect of blood removal by perfusion in vivo.

    Science.gov (United States)

    Orct, Tatjana; Jurasović, Jasna; Micek, Vedran; Karaica, Dean; Sabolić, Ivan

    2017-03-01

    Concentrations of macro- and microelements in animal organs indicate the animal health status and represent reference data for animal experiments. Their levels in blood and tissues could be different between sexes, and could be different with and without blood in tissues. To test these hypotheses, in adult female and male rats the concentrations of various elements were measured in whole blood, blood plasma, and tissues from blood-containing (nonperfused) and blood-free liver, kidneys, and brain (perfused in vivo with an elements-free buffer). In these samples, 6 macroelements (Na, Mg, P, S, K, Ca) and 14 microelements (Fe, Mn, Co, Cu, Zn, Se, I, As, Cd, Hg, Pb, Li, B, Sr) were determined by inductively coupled plasma mass spectrometry following nitric acid digestion. In blood and plasma, female- or male-dominant sex differences were observed for 6 and 5 elements, respectively. In nonperfused organs, sex differences were observed for 3 (liver, brain) or 9 (kidneys) elements, whereas in perfused organs, similar differences were detected for 9 elements in the liver, 5 in the kidneys, and none in the brain. In females, perfused organs had significantly lower concentrations of 4, 5, and 2, and higher concentrations of 10, 4, and 7 elements, respectively, in the liver, kidneys, and brain. In males, perfusion caused lower concentrations of 4, 7, and 2, and higher concentrations of 1, 1, and 7 elements, respectively, in the liver, kidneys, and brain. Therefore, the residual blood in organs can significantly influence tissue concentrations of various elements and their sex-dependency. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Plastic Surgery in the Multimodal Treatment Concept of Soft Tissue Sarcoma: Influence of Radiation, Chemotherapy, and Isolated Limb Perfusion on Plastic Surgery Techniques

    OpenAIRE

    Kapalschinski, Nicolai; Goertz, Ole; Harati, Kamran; Kueckelhaus, Maximilian; Kolbenschlag, Jonas; Lehnhardt, Marcus; Hirsch, Tobias

    2015-01-01

    Surgical intervention is the mainstay treatment for soft tissue sarcomas. The significance of adjuvant and neoadjuvant therapies such as chemotherapy, radiation and isolated limb perfusion remains under controversial discussion. The goal of this review is to discuss the effects of the aforementioned treatment modalities and their timing of application on plastic surgery techniques. Furthermore, options of reconstruction in cases of complications caused by adjuvant and neoadjuvant therapies ar...

  15. Visualizing feasible operating ranges within tissue engineering systems using a "windows of operation" approach: a perfusion-scaffold bioreactor case study.

    Science.gov (United States)

    McCoy, Ryan J; O'Brien, Fergal J

    2012-12-01

    Tissue engineering approaches to developing functional substitutes are often highly complex, multivariate systems where many aspects of the biomaterials, bio-regulatory factors or cell sources may be controlled in an effort to enhance tissue formation. Furthermore, success is based on multiple performance criteria reflecting both the quantity and quality of the tissue produced. Managing the trade-offs between different performance criteria is a challenge. A "windows of operation" tool that graphically represents feasible operating spaces to achieve user-defined levels of performance has previously been described by researchers in the bio-processing industry. This paper demonstrates the value of "windows of operation" to the tissue engineering field using a perfusion-scaffold bioreactor system as a case study. In our laboratory, perfusion bioreactor systems are utilized in the context of bone tissue engineering to enhance the osteogenic differentiation of cell-seeded scaffolds. A key challenge of such perfusion bioreactor systems is to maximize the induction of osteogenesis but minimize cell detachment from the scaffold. Two key operating variables that influence these performance criteria are the mean scaffold pore size and flow-rate. Using cyclooxygenase-2 and osteopontin gene expression levels as surrogate indicators of osteogenesis, we employed the "windows of operation" methodology to rapidly identify feasible operating ranges for the mean scaffold pore size and flow-rate that achieved user-defined levels of performance for cell detachment and differentiation. Incorporation of such tools into the tissue engineer's armory will hopefully yield a greater understanding of the highly complex systems used and help aid decision making in future translation of products from the bench top to the market place. Copyright © 2012 Wiley Periodicals, Inc.

  16. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    Energy Technology Data Exchange (ETDEWEB)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B. [Charite-Universitaetsmedizin, Academic Neuroradiology, Center for Stroke Research (CSB), Berlin (Germany); Grittner, Ulrike [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Charite, Department for Biostatistics and Clinical Epidemiology, Berlin (Germany); Schneider, Alice [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Rocco, Andrea [Charite, Department of Neurology and Center for Stroke Research, Berlin (Germany)

    2016-05-15

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg{sub n} = img{sub n} + 1 - img{sub n} - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  17. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    International Nuclear Information System (INIS)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B.; Grittner, Ulrike; Schneider, Alice; Rocco, Andrea

    2016-01-01

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg n = img n + 1 - img n - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  18. Microfluidic culture chamber for the long-term perfusion and precise chemical stimulation of organotypic brain tissue slices

    DEFF Research Database (Denmark)

    Caicedo, H. H.; Vignes, M.; Brugg, B.

    2010-01-01

    We have developed a microfluidic perfusion-based culture system to study long-term in-vitro responses of organo-typic brain slices exposed to localized neurochemical stimulation. Using this microperfusion chamber we show that hip-pocampal organotypic brain slices cultures grown on nitrocellulose ...

  19. Release of Tissue-specific Proteins into Coronary Perfusate as a Model for Biomarker Discovery in Myocardial Ischemia/Reperfusion Injury

    DEFF Research Database (Denmark)

    Cordwell, Stuart; Edwards, Alistair; Liddy, Kiersten

    2012-01-01

    of 60 min reperfusion following brief, reversible ischemia (15 min; 15I/60R) for comparison with irreversible I/R (60I/60R). Perfusate proteins were separated using two-dimensional gel electrophoresis (2-DE) and identified by mass spectrometry (MS), revealing 26 tissue-specific proteins released during...... reperfusion post-15I. Proteins released during irreversible I/R (60I/60R) were profiled using gel-based (2-DE and one-dimensional gel electrophoresis coupled to liquid chromatography and tandem mass spectrometry; geLC–MS) and gel-free (LC–MS/MS) methods. A total of 192 tissue-specific proteins were identified......Diagnosis of acute coronary syndromes is based on protein biomarkers, such as the cardiac troponins (cTnI/cTnT) and creatine kinase (CK-MB) that are released into the circulation. Biomarker discovery is focused on identifying very low abundance tissue-derived analytes from within albumin...

  20. Comparing CT perfusion with oxygen partial pressure in a rabbit VX2 soft-tissue tumor model

    International Nuclear Information System (INIS)

    Sun Changjin; Li Chao; Lv Haibo

    2014-01-01

    The aim of this study was to evaluate the oxygen partial pressure of the rabbit model of the VX2 tumor using a 64-slice perfusion CT and to compare the results with that obtained using the oxygen microelectrode method. Perfusion CT was performed for 45 successfully constructed rabbit models of a VX2 brain tumor. The perfusion values of the brain tumor region of interest, the blood volume (BV), the time to peak (TTP) and the peak enhancement intensity (PEI) were measured. The results were compared with the partial pressure of oxygen (PO2) of that region of interest obtained using the oxygen microelectrode method. The perfusion values of the brain tumor region of interest in 45 successfully constructed rabbit models of a VX2 brain tumor ranged from 1.3–127.0 (average, 21.1 ± 26.7 ml/min/ml); BV ranged from 1.2–53.5 ml/100g (average, 22.2 ± 13.7 ml/100g); PEI ranged from 8.7–124.6 HU (average, 43.5 ± 28.7 HU); and TTP ranged from 8.2–62.3 s (average, 38.8 ± 14.8 s). The PO2 in the corresponding region ranged from 0.14–47 mmHg (average, 16 ± 14.8 mmHg). The perfusion CT positively correlated with the tumor PO2, which can be used for evaluating the tumor hypoxia in clinical practice. (author)

  1. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

  2. The precision of DCE-MRI using the tissue homogeneity model with continuous formulation of the perfusion parameters

    Czech Academy of Sciences Publication Activity Database

    Bartoš, Michal; Jiřík, Radovan; Kratochvíla, Jiří; Standara, M.; Starčuk jr., Zenon; Torfinn, T.

    2014-01-01

    Roč. 32, č. 5 (2014), s. 505-513 ISSN 0730-725X R&D Projects: GA ČR GAP102/12/2380; GA MŠk ED0017/01/01; GA MŠk(CZ) LO1212 Institutional support: RVO:67985556 ; RVO:68081731 Keywords : dynamic contrast-enhanced MRI (DCE-MRI) * perfusion * parameter estimation * bolus arrival time Subject RIV: FS - Medical Facilities ; Equipment Impact factor: 2.090, year: 2014

  3. Adrenal secretion of catecholamines by inhalation of radon water in relation to an increase of the tissue perfusion rate in rabbits

    International Nuclear Information System (INIS)

    Suzuka, Ichio

    1993-01-01

    To clarify the relationship between the increase in subcutaneous tissue perfusion rate (TPR) upon inhalation of radon water and the vasoactive effects of radon, rabbits inhaled nebulized water containing 14,000-18,000 Bq/1 radon (radon group) taken from Ikeda Mineral Spring, Shimane, Japan. Control rabbits inhaled radon water from the same springs which had been kept for over 10 radon half-life periods. TPR was evaluated 15 minutes after the beginning of inhalation by mass spectrometry. After inhalation for 90 minutes, plasma and adrenal glands were removed, and levels of adrenaline and noradrenaline were analyzed by high-performance liquid chromatography (THI method). Each group was divided into 4 subgroups according to intravenously injected medication as follows: 1) no medication (without adrenergic blocker), 2) phentolamine (α-blocker), 0.05 mg/kg/min, 3) propranolol (non-selective β-blocker), 1 mg/kg/, and 4) atenolol (selective β-blocker), 6 mg/kg. In the radon group, plasma adrenaline and noradrenaline levels were significantly higher (p 1 -action of catecholamines contributes to the increase in tissue perfusion. (author)

  4. Perfusion pattern and time of vascularisation with CEUS increase accuracy in differentiating between benign and malignant tumours in 216 musculoskeletal soft tissue masses

    Energy Technology Data Exchange (ETDEWEB)

    De Marchi, Armanda, E-mail: armanda.demarchi@tiscali.it [Department of Imaging, Azienda Ospedaliera Città della Salute e della Scienza, CTO Hospital, Via Zuretti 29, 10126 Torino (Italy); Prever, Elena Brach del, E-mail: elena.brach@unito.it [Department of OrthopaedicOncology and ReconstructiveSurgery, Azienda Ospedaliero Universitaria Città della Salute e della Scienza, CTO Hospital, Via Zuretti 29, 10126 Torino (Italy); Cavallo, Franco, E-mail: franco.cavallo@unito.it [Department of Public health and Paediatrics, University of Turin, Via Santena 5-bis, 10126 Torino (Italy); Pozza, Simona, E-mail: simona.pozza@tin.it [Department of Imaging, Azienda Ospedaliera Città della Salute e della Scienza, CTO Hospital, Via Zuretti 29, 10126 Torino (Italy); Linari, Alessandra, E-mail: linaralessandra@libero.it [Department of Pathology, Azienda Ospedaliero Universitaria Città della Salute e della Scienza, Regina Margherita Hospital, Piazza Polonia, 10126 Torino (Italy); Lombardo, Paolo, E-mail: pao.lombardo82@gmail.com [Department of DiagnosticImaging and Radiotherapy of the University of Turin, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Genova 3, 10126 Torino (Italy); Comandone, Alessandro, E-mail: alessandro.comandone@gradenigo.it [Department of Oncology, Gradenigo Hospital, Corso Regina Margherita, 8/10.10153 Torino (Italy); Piana, Raimondo, E-mail: raimondo.piana@libero.it [Department of OrthopaedicOncology and ReconstructiveSurgery, Azienda Ospedaliero Universitaria Città della Salute e della Scienza, CTO Hospital, Via Zuretti 29, 10126 Torino (Italy); Faletti, Carlo [Department of Imaging, Azienda Ospedaliera Città della Salute e della Scienza, CTO Hospital, Via Zuretti 29, 10126 Torino (Italy)

    2015-01-15

    Introduction: Musculoskeletal Soft Tissue Tumours (STT) are frequent heterogeneous lesions. Guidelines consider a mass larger than 5 cm and deep with respect to the deep fascia potentially malignant. Contrast Enhanced Ultrasound (CEUS) can detect both vascularity and tumour neoangiogenesis. We hypothesised that perfusion patterns and vascularisation time could improve the accuracy of CEUS in discriminating malignant tumours from benign lesions. Materials and methods: 216 STT were studied: 40% benign lesions, 60% malignant tumours, 56% in the lower limbs. Seven CEUS perfusion patterns and three types of vascularisation (arterial-venous uptake, absence of uptake) were applied. Accuracy was evaluated by comparing imaging with the histological diagnosis. Univariate and multivariate analysis, Chi-square test and t-test for independent variables were applied; significance was set at p < 0.05 level, 95% computed CI. Results: CEUS pattern 6 (inhomogeneous perfusion), arterial uptake and location in the lower limb were associated with high risk of malignancy. CEUS pattern has PPV 77%, rapidity of vascularisation PPV 69%; location in the limbs is the most sensitive indicator, but NPV 52%, PPV 65%. The combination of CEUS-pattern and vascularisation has 74% PPV, 60% NPV, 70% sensitivity. No correlation with size and location in relation to the deep fascia was found. Conclusion: US with CEUS qualitative analysis could be an accurate technique to identify potentially malignant STT, for which second line imaging and biopsy are indicated in Referral Centers. Intense inhomogeneous enhancement with avascular areas and rapid vascularisation time could be useful in discriminating benign from malignant SST, overall when the lower limbs are involved.

  5. CT perfusion as an imaging biomarker in monitoring response to neoadjuvant bevacizumab and radiation in soft-tissue sarcomas: comparison with tumor morphology, circulating and tumor biomarkers, and gene expression.

    Science.gov (United States)

    Kambadakone, Avinash; Yoon, Sam S; Kim, Tae-Min; Karl, Daniel L; Duda, Dan G; DeLaney, Thomas F; Sahani, Dushyant V

    2015-01-01

    The purpose of this study was to evaluate the role of CT perfusion in monitoring response to neoadjuvant antiangiogenic and radiation therapy in resectable soft-tissue sarcomas and correlate the findings with tumor size, circulating and tumor biomarkers, and gene expression. This phase II clinical trial included 20 patients (13 men and 7 women; mean age, 55 years) with soft-tissue sarcomas who were undergoing treatment with the antiangiogenic drug bevacizumab followed by bevacizumab, radiation, and surgical resection. The patients underwent CT perfusion and diagnostic contrast-enhanced CT at baseline, at 2 weeks after bevacizumab therapy, and after completion of bevacizumab and radiation therapy. Multiple CT perfusion parameters (blood flow, blood volume, mean transit time, and permeability) were correlated with tumor size, circulating and tumor biomarkers, and gene expression. Two weeks after bevacizumab therapy, there was substantial fall in blood volume (31.9% reduction, p = 0.01) with more pronounced reduction in blood flow, blood volume, and permeability after treatment completion (53-64% reduction in blood flow, blood volume, and permeability; p = 0.001), whereas tumor size showed no significant change (p = 0.34). Tumors with higher baseline blood volume and lower baseline tumor size showed superior response to bevacizumab and radiation (p = 0.05). There was also an increase in median plasma vascular endothelial growth factor and placental-derived growth factor concentration after bevacizumab therapy paralleled by a decrease in tumor perfusion depicted by CT perfusion, although this was not statistically significant (p = 0.4). The baseline tumor microvessel density (MVD) correlated with blood flow (p = 0.04). At least 20 different genes were differentially expressed in tumors with higher and lower baseline perfusion. CT perfusion is more sensitive than tumor size for monitoring early and late response to bevacizumab and radiation therapy. CT perfusion

  6. Magnetic resonance perfusion imaging without contrast media

    International Nuclear Information System (INIS)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz; Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D.

    2010-01-01

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  7. Plastic surgery in the multimodal treatment concept of soft tissue sarcoma: Influence of radiation, chemotherapy and isolated limb perfusion on plastic surgery techniques

    Directory of Open Access Journals (Sweden)

    Nicolai eKapalschinski

    2015-12-01

    Full Text Available Surgical intervention is the mainstay treatment for soft tissue sarcomas. The significance of adjuvant and neoadjuvant therapies such as chemotherapy, radiation and isolated limb perfusion remains under controversial discussion. The goal of this review is to discuss the effects of the aforementioned treatment modalities and their timing of application on plastic surgery techniques. Furthermore, options of reconstruction in cases of complications caused by adjuvant and neoadjuvant therapies are discussed. When compared with adjuvant radiation, neoadjuvant treatment can reduce negative side effects such as fibrosis and edema, because radioderma can be removed during the subsequent surgical procedure. Furthermore, there have not been any reports of negative effects of neoadjuvant radiation on microsurgical procedures. However, the dose of neoadjuvant radiation correlates with increased risks of impaired wound healing postoperatively. Thus, a patient-specific approach to decide whether radiation should be performed adjuvant or neoadjuvant is necessary. Pre-operative irradiation should be considered in cases where functional structures are exposed after tumor resection, in order to ensure the best possible functionality. Adjuvant radiation should be considered in all other cases because of its known superior wound healing. .As for chemotherapy, no negative influence of its use adjuvant or neoadjuvant to reconstructive procedures such as local or free flaps has been reported. Lastly, small sample size studies have not shown increased risks of microsurgical failure or wound complications after isolated limb perfusion. The findings of this review suggest that the chronological order of the discussed therapeutic approaches is not a decisive factor in the surgical outcome of reconstructive procedures for soft tissue sarcoma.

  8. : Myocardial Perfusion

    OpenAIRE

    Dacher, Jean-Nicolas; Lefebvre, V.; Dubourg, Bernard; Deux, Jean-François; Caudron, Jérôme

    2013-01-01

    International audience; The analysis of myocardial perfusion is a key step in the cardiac MRI examination. In routine work, this exploration carried out at rest is based on the qualitative first pass study of gadolinium with an ECG-triggered saturation recovery bFFE sequence. In view of recent knowledge, the analysis of the myocardial perfusion under vasodilator stress may be carried out by scintigraphy or MRI, the latter benefiting from the absence of exposure to ionizing rays and a lower co...

  9. Plastic Surgery in the Multimodal Treatment Concept of Soft Tissue Sarcoma: Influence of Radiation, Chemotherapy, and Isolated Limb Perfusion on Plastic Surgery Techniques.

    Science.gov (United States)

    Kapalschinski, Nicolai; Goertz, Ole; Harati, Kamran; Kueckelhaus, Maximilian; Kolbenschlag, Jonas; Lehnhardt, Marcus; Hirsch, Tobias

    2015-01-01

    Surgical intervention is the mainstay treatment for soft tissue sarcomas (STSs). The significance of adjuvant and neoadjuvant therapies, such as chemotherapy, radiation, and isolated limb perfusion, remains under controversial discussion. The goal of this review is to discuss the effects of the aforementioned treatment modalities and their timing of application in plastic surgery techniques. Furthermore, options of reconstruction in cases of complications caused by adjuvant and neoadjuvant therapies are discussed. When compared with adjuvant radiation, neoadjuvant treatment can reduce negative side effects such as fibrosis and edema because radioderma can be removed during the subsequent surgical procedure. Furthermore, there have not been any reports of negative effects of neoadjuvant radiation on microsurgical procedures. However, the dose of neoadjuvant radiation correlates with increased risks of impaired wound healing postoperatively. Thus, a patient-specific approach to decide whether radiation should be performed adjuvant or neoadjuvant is necessary. Preoperative irradiation should be considered in cases where functional structures are exposed after tumor resection, in order to ensure the best possible functionality. Adjuvant radiation should be considered in all other cases because of its known superior wound healing. As for chemotherapy, no negative influence of its use adjuvant or neoadjuvant to reconstructive procedures, such as local or free flaps, has been reported. Lastly, small sample size studies have not shown increased risks of microsurgical failure or wound complications after isolated limb perfusion. The findings of this review suggest that the chronological order of the discussed therapeutic approaches is not a decisive factor in the surgical outcome of reconstructive procedures for STS.

  10. Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass

    Science.gov (United States)

    Soller, Babs R.; Idwasi, Patrick O.; Balaguer, Jorge; Levin, Steven; Simsir, Sinan A.; Vander Salm, Thomas J.; Collette, Helen; Heard, Stephen O.

    2003-01-01

    OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and

  11. Espectroscopia no infravermelho próximo para a monitorização da perfusão tecidual Near-infrared spectroscopy for monitoring peripheral tissue perfusion in critically ill patients

    Directory of Open Access Journals (Sweden)

    Alexandre Lima

    2011-09-01

    Full Text Available A espectroscopia no infravermelho próximo (NIRS tem sido principalmente usada na investigação da oxigenação periférica tecidual de forma não invasiva e contínua. O princípio da espectroscopia consiste na aplicação da luz no comprimento de onda do infravermelho-próximo para avaliar, de forma quantitativa e qualitativa, os componentes moleculares relacionadas à oxigenação tecidual. Baseado na relação das concentrações da deoxiemoglobina e da oxiemoglobina no tecido, a NIRS obtém informações para o cálculo da oxigenação tecidual. Embora possa ser aplicada em qualquer órgão, como método não invasivo é principalmente usada para a monitorização da oxigenação muscular periférica. Os parâmetros medidos pela NIRS podem ser calculados diretamente ou através de intervenções fisiológicas para alterar a circulação no local da aferição, sendo as mais usadas a oclusão arterial e a oclusão venosa. Deste modo, pode-se obter informações sobre a saturação do oxigênio muscular periférico e tecidual, bem como do fluxo sanguíneo e consumo de oxigênio local. Seu uso é direcionado principalmente para a monitorização da oxigenação tecidual periférica durante ressuscitação do choque no trauma e em pacientes sépticos, bem como a monitorização dos distúrbios da microcirculação regional. Esta revisão abordará os princípios físicos da espectroscopia no IV-próximo, e das principais aplicações clínicas deste instrumento de monitorização, com ênfase nos estudos que investigaram a utilidade da NIRS na área de terapia intensiva e também no setor de emergência clínica.Near infrared spectroscopy (NIRS is a non-invasive technique that allows determination of tissue oxygenation based on spectro-photometric quantitation of oxy- and deoxyhemoglobin within a tissue. This technique has gained acceptance as a tool to monitor peripheral tissue perfusion in critically ill patient. NIRS principle is based on

  12. Mortality and Outcome Comparison Between Brain Tissue Oxygen Combined with Intracranial Pressure/Cerebral Perfusion Pressure-Guided Therapy and Intracranial Pressure/Cerebral Perfusion Pressure-Guided Therapy in Traumatic Brain Injury: A Meta-Analysis.

    Science.gov (United States)

    Xie, Qiang; Wu, Hai-Bing; Yan, Yu-Feng; Liu, Meng; Wang, Er-Song

    2017-04-01

    The combination of brain tissue oxygen and standard intracranial pressure (ICP)/cerebral perfusion pressure (CPP)-guided therapy is thought to improve traumatic brain injury (TBI) prognosis compared with standard ICP/CPP-guided therapy. However, related results of previous observational studies and recently published cohort studies and randomized controlled trials (RCTs) remain controversial. The objective of this study was to compare the effect of the combined therapy with that of standard ICP/CPP-guided therapy on mortality rate, favorable outcome, ICP/CPP, and length of stay (LOS). We systematically searched PubMed, Embase, Cochrane Library, ClinicalTrials.gov, and Web of Science in July 2016 for studies comparing the combined therapy and standard ICP/CPP-guided therapy. Random-effect and fixed-effect models were used for pooled analyses. After screening 362 studies, 8 cohort studies and 1 RCT were included. Primary outcomes were mortality and favorable outcome. The overall mortality risk ratio showed no obvious advantages between the 2 groups (risk ratio [RR], 0.76; 95% confidence interval [CI], 0.54-1.06) and discharge mortality (RR, 1.01; 95% CI, 0.80-1.26) and 3-month mortality (RR, 0.77; 95% CI, 0.53-1.12). Compared with the ICP/CPP group, the combined group was more likely to achieve better outcome during the 6 months after TBI (RR, 1.26; 95% CI, 1.04-1.52) or exactly at 6 months (RR, 1.34; 95% CI, 1.07-1.68), whereas ICP (standardized mean difference [SMD], -0.19; 95% CI, -0.43 to 0.05), CPP (SMD, 0.13; 95% CI, -0.09 to 0.35), and LOS (SMD, 0.13; 95% CI, -0.11 to 0.37) showed no obvious differences. Compared with standard ICP/CPP-guided therapy, brain tissue oxygen combined with ICP/CPP-guided therapy improved long-term outcomes without any effects on mortality, ICP/CPP, or LOS. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Experimental Approach to Evaluate the 11C Perfusion and Diffusion in Small Animal Tissues for HadronPET Applications.

    Directory of Open Access Journals (Sweden)

    Immaculada Martínez-Rovira

    Full Text Available The development of a reliable dose monitoring system in hadron therapy is essential in order to control the treatment plan delivery. Positron Emission Tomography (PET is the only method used in clinics nowadays for quality assurance. However, the accuracy of this method is limited by the loss of signal due to the biological washout processes. Up to the moment, very few studies measured the washout processes and there is no database of washout data as a function of the tissue and radioisotope. One of the main difficulties is related to the complexity of such measurements, along with the limited time slots available in hadron therapy facilities. Thus, in this work, we proposed an alternative in vivo methodology for the measurement and modeling of the biological washout parameters without any radiative devices. It consists in the implementation of a point-like radioisotope source by direct injection on the tissues of interest and its measurement by means of high-resolution preclinical PET systems. In particular, the washout of 11C carbonate radioisotopes was assessed, considering that 11C is is the most abundant β+ emitter produced by carbon beams. 11C washout measurements were performed in several tissues of interest (brain, muscle and 9L tumor xenograf in rodents (Wistar rat. Results show that the methodology presented is sensitive to the washout variations depending on the selected tissue. Finally, a first qualitative correlation between 11C tumor washout properties and tumor metabolism (via 18F-FDG tracer uptake was found.

  14. Experimental verification of bioheat transfer theories: measurement of temperature profiles around large artificial vessels in perfused tissue

    NARCIS (Netherlands)

    Crezee, J.; Lagendijk, J. J.

    1990-01-01

    The verification of thermal models for use in hyperthermia treatment planning is essential. We investigated the heat transfer between a single vessel and the surrounding vascularised tissue, comparing the conventional bioheat transfer theory and the recently developed keff model using analytical and

  15. Consequences of Inadequate Physical Activity

    Centers for Disease Control (CDC) Podcasts

    2018-03-27

    Listen as CDC Epidemiologist Susan Carlson, PhD, talks about her research, which estimates the percentage of US deaths attributed to inadequate levels of physical activity.  Created: 3/27/2018 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/27/2018.

  16. Radiologists' responses to inadequate referrals

    International Nuclear Information System (INIS)

    Lysdahl, Kristin Bakke; Hofmann, Bjoern Morten; Espeland, Ansgar

    2010-01-01

    To investigate radiologists' responses to inadequate imaging referrals. A survey was mailed to Norwegian radiologists; 69% responded. They graded the frequencies of actions related to referrals with ambiguous indications or inappropriate examination choices and the contribution of factors preventing and not preventing an examination of doubtful usefulness from being performed as requested. Ninety-five percent (344/361) reported daily or weekly actions related to inadequate referrals. Actions differed among subspecialties. The most frequent were contacting the referrer to clarify the clinical problem and checking test results/information in the medical records. Both actions were more frequent among registrars than specialists and among hospital radiologists than institute radiologists. Institute radiologists were more likely to ask the patient for additional information and to examine the patient clinically. Factors rated as contributing most to prevent doubtful examinations were high risk of serious complications/side effects, high radiation dose and low patient age. Factors facilitating doubtful examinations included respect for the referrer's judgment, patient/next-of-kin wants the examination, patient has arrived, unreachable referrer, and time pressure. In summary, radiologists facing inadequate referrals considered patient safety and sought more information. Vetting referrals on arrival, easier access to referring clinicians, and time for radiologists to handle inadequate referrals may contribute to improved use of imaging. (orig.)

  17. Whole brain CT perfusion on a 320-slice CT scanner

    Directory of Open Access Journals (Sweden)

    Jai Jai Shiva Shankar

    2011-01-01

    Full Text Available Computed tomography perfusion (CTP has been criticized for limited brain coverage. This may result in inadequate coverage of the lesion, inadequate arterial input function, or omission of the lesion within the target perfusion volume. The availability of 320-slice CT scanners offers whole brain coverage. This minimizes the chances of misregistration of lesions regardless of location, and makes the selection of the arterial input function easy. We present different clinical scenarios in which whole brain CTP is especially useful.

  18. BaroFuse, a novel pressure-driven, adjustable-throughput perfusion system for tissue maintenance and assessment

    Directory of Open Access Journals (Sweden)

    Austin Rountree

    2016-12-01

    Conclusions: The very low flow rates and simplicity of design and operation of the BaroFuse device allow for the efficient generation of large number of kinetic profiles in OCR and other endpoints lasting from hours to days. The use of flow enhances the ability to make measurements on primary tissue where some elements of native three-dimensional structure are preserved. We offer the BaroFuse as a powerful tool for physiological studies and for pharmaceutical assessment of drug effects as well as personalized medicine.

  19. Strong static magnetic fields of NMR: Do they affect tissue perfusion. Beeinflussen starke statische Magnetfelder in der NMR-Tomographie die Gewebedurchblutung

    Energy Technology Data Exchange (ETDEWEB)

    Stick, C.; Hinkelmann, K. (Kiel Univ. (Germany, F.R.). Inst. fuer Angewandte Physiologie und Medizinische Klimatologie); Eggert, P. (Kiel Univ. (Germany, F.R.). Abt. Allgemeine Paediatrie); Wendhausen, H. (Kiel Univ. (Germany, F.R.). Abt. Radiologie)

    1991-03-01

    Findings obtained in humans and test animals raised the question whether strong static magnetic fields as used in NMR-tomography may affect tissue perfusion. In two test series including 20 subjects, each skin blood flow at the thumb was determined by heat clearance, and forearm blood flow was measured by venous occlusion plethysmography. For comparative purposes, measurements were carried out bilaterally at both extremities. The experiments consisted of three sections that lasted 10 min each. During the second section the thumb or the forearm were unilaterally exposed to magnetic fields of 0,9 to 1 T and 0.4 to 0.5 T, respectively. The results of this section were compared with the values obtained during the experimental sections prior to and after the exposure to the magnetic field. The results were also compared with the blood flow measured at the contralateral extremity. Neither at the skin of the thumb nor at the forearm were there changes in local blood flow attributable to the magnetic fields applied. (orig.).

  20. Perfusion CT in acute stroke

    International Nuclear Information System (INIS)

    Eckert, Bernd; Roether, Joachim; Fiehler, Jens; Thomalla, Goetz

    2015-01-01

    Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

  1. Monte Carlo estimation of scatter effects on quantitative myocardial blood flow and perfusable tissue fraction using 3D-PET and 15O-water

    Science.gov (United States)

    Hirano, Yoshiyuki; Koshino, Kazuhiro; Watabe, Hiroshi; Fukushima, Kazuhito; Iida, Hidehiro

    2012-11-01

    In clinical cardiac positron emission tomography using 15O-water, significant tracer accumulation is observed not only in the heart but also in the liver and lung, which are partially outside the field-of-view. In this work, we investigated the effects of scatter on quantitative myocardium blood flow (MBF) and perfusable tissue fraction (PTF) by a precise Monte Carlo simulation (Geant4) and a numerical human model. We assigned activities to the heart, liver, and lung of the human model with varying ratios of organ activities according to an experimental time activity curve and created dynamic sinograms. The sinogram data were reconstructed by filtered backprojection. By comparing a scatter-corrected image (SC) with a true image (TRUE), we evaluated the accuracy of the scatter correction. TRUE was reconstructed using a scatter-eliminated sinogram, which can be obtained only in simulations. A scatter-uncorrected image (W/O SC) and an attenuation-uncorrected image (W/O AC) were also constructed. Finally, we calculated MBF and PTF with a single tissue-compartment model for four types of images. As a result, scatter was corrected accurately, and MBFs derived from all types of images were consistent with the MBF obtained from TRUE. Meanwhile, the PTF of only the SC was in agreement with the PTF of TRUE. From the simulation results, we concluded that quantitative MBF is less affected by scatter and absorption in 3D-PET using 15O-water. However, scatter correction is essential for accurate PTF.

  2. Intracoronary Administration of Allogeneic Adipose Tissue-Derived Mesenchymal Stem Cells Improves Myocardial Perfusion But Not Left Ventricle Function, in a Translational Model of Acute Myocardial Infarction.

    Science.gov (United States)

    Bobi, Joaquim; Solanes, Núria; Fernández-Jiménez, Rodrigo; Galán-Arriola, Carlos; Dantas, Ana Paula; Fernández-Friera, Leticia; Gálvez-Montón, Carolina; Rigol-Monzó, Elisabet; Agüero, Jaume; Ramírez, José; Roqué, Mercè; Bayés-Genís, Antoni; Sánchez-González, Javier; García-Álvarez, Ana; Sabaté, Manel; Roura, Santiago; Ibáñez, Borja; Rigol, Montserrat

    2017-05-03

    Autologous adipose tissue-derived mesenchymal stem cells (ATMSCs) therapy is a promising strategy to improve post-myocardial infarction outcomes. In a porcine model of acute myocardial infarction, we studied the long-term effects and the mechanisms involved in allogeneic ATMSCs administration on myocardial performance. Thirty-eight pigs underwent 50 minutes of coronary occlusion; the study was completed in 33 pigs. After reperfusion, allogeneic ATMSCs or culture medium (vehicle) were intracoronarily administered. Follow-ups were performed at short (2 days after acute myocardial infarction vehicle-treated, n=10; ATMSCs-treated, n=9) or long term (60 days after acute myocardial infarction vehicle-treated, n=7; ATMSCs-treated, n=7). At short term, infarcted myocardium analysis showed reduced apoptosis in the ATMSCs-treated animals (48.6±6% versus 55.9±5.7% in vehicle; P =0.017); enhancement of the reparative process with up-regulated vascular endothelial growth factor, granulocyte macrophage colony-stimulating factor, and stromal-derived factor-1α gene expression; and increased M2 macrophages (67.2±10% versus 54.7±10.2% in vehicle; P =0.016). In long-term groups, increase in myocardial perfusion at the anterior infarct border was observed both on day-7 and day-60 cardiac magnetic resonance studies in ATMSCs-treated animals, compared to vehicle (87.9±28.7 versus 57.4±17.7 mL/min per gram at 7 days; P =0.034 and 99±22.6 versus 43.3±14.7 22.6 mL/min per gram at 60 days; P =0.0001, respectively). At day 60, higher vascular density was detected at the border zone in the ATMSCs-treated animals (118±18 versus 92.4±24.3 vessels/mm 2 in vehicle; P =0.045). Cardiac magnetic resonance-measured left ventricular ejection fraction of left ventricular volumes was not different between groups at any time point. In this porcine acute myocardial infarction model, allogeneic ATMSCs-based therapy was associated with increased cardioprotective and reparative

  3. Rapid pH and PO2 changes in the tissue recording chamber during stoppage of a gas-equilibrated perfusate: effects on calcium currents in ventral horn neurons.

    Science.gov (United States)

    Carlin, K P; Brownstone, R M

    2006-09-01

    In vitro studies often use bicarbonate-buffered saline solutions to mimic the normal extracellular environment of tissues. These solutions are typically equilibrated with gaseous O2 and CO2, the latter interacting with bicarbonate ions to maintain a physiological pH. In vitro tissue chambers, like those used for electrophysiology, are usually continually perfused with the gassed buffer, but stopping the perfusion to add expensive chemicals or acquire imaging data is a common practice. The present study demonstrates that this procedure leads to rapid (PO2 of the detained solution in the tissue chamber. During the first 200 s, pH increased by 0.4 units and resulted in a 25% PO2 reduction of the detained solution. The rates of these changes were dependent on the volume of solution in the chamber. In experiments using acute transverse slices from the lumbar spinal cord of neonatal (postnatal day 0-10) mice, perfusion stoppage of the same duration was accompanied by a 34.7% enhancement of the peak voltage-gated calcium current recorded from ventral horn neurons. In these cells both low voltage-activated and high voltage-activated currents were affected. These currents were unaffected by decreasing PO2 when a CO2-independent buffer was used, suggesting that changes in pH were responsible for the observed effects. It is concluded that the procedure of stopping a bicarbonate/CO2-buffered perfusate results in rapid changes in pH and PO2 of the solution detained in the tissue chamber, and that these changes have the potential to covertly influence experimental results.

  4. Standardized perfusion value of the esophageal carcinoma and its correlation with quantitative CT perfusion parameter values.

    Science.gov (United States)

    Djuric-Stefanovic, A; Saranovic, Dj; Sobic-Saranovic, D; Masulovic, D; Artiko, V

    2015-03-01

    Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (rS). Median SPV of the esophageal carcinoma (7.1; range: 2.8-13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4-2.4), (Z=-5.511, pCT perfusion measurements and statistically significant correlation was proved. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. [Inadequate treatment of affective disorders].

    Science.gov (United States)

    Bergsholm, P; Martinsen, E W; Holsten, F; Neckelmann, D; Aarre, T F

    1992-08-30

    Inadequate treatment of mood (affective) disorders is related to the mind/body dualism, desinformation about methods of treatment, the stigma of psychiatry, low funding of psychiatric research, low educational priority, and slow acquisition of new knowledge of psychiatry. The "respectable minority rule" has often been accepted without regard to the international expertise, and the consequences of undertreatment have not been weighed against the benefits of optimal treatment. The risk of chronicity increases with delayed treatment, and inadequately treated affective disorders are a leading cause of suicide. During the past 20 years the increase in suicide mortality in Norway has been the second largest in the world. Severe mood disorders are often misclassified as schizophrenia or other non-affective psychoses. Atypical mood disorders, notably rapid cycling and bipolar mixed states, are often diagnosed as personality, adjustment, conduct, attention deficit, or anxiety disorders, and even mental retardation. Neuroleptic drugs may suppress the most disturbing features of mood disorders, a fact often misinterpreted as supporting the diagnosis of a schizophrenia-like disorder. Treatment with neuroleptics is not sufficient, however, and serious side effects may often occur. The consequences are too often social break-down and post-depression syndrome.

  6. Washout of 82Rb as a marker of impaired tissue integrity, obtained by list-mode cardiac PET/CT: relationship with perfusion/metabolism patterns of myocardial viability

    International Nuclear Information System (INIS)

    Chien, David T.; Bravo, Paco; Higuchi, Takahiro; Merrill, Jennifer; Bengel, Frank M.

    2011-01-01

    Myocardial washout of the potassium analogue 82 Rb may indicate tissue impairment. Few studies have evaluated its usefulness for viability assessment, and controversial results were reported. We revisited this topic using list-mode positron emission tomography (PET)/CT. A total of 22 patients with chronic ischemic cardiomyopathy (ICM) and 11 control subjects with normal CT coronary angiogram were studied. Rest 82 Rb PET/CT studies were acquired in list mode and resampled to static, gated, and dynamic images. Using a 17-segment model, 82 Rb washout was determined by monoexponential fitting of myocardial time-activity curves. In ICM patients, 18 F-fluorodeoxyglucose (FDG) studies were obtained in the same session and segments were classified as normally perfused, mismatch, or matched defect. 82 Rb washout was minimal and homogeneous in control subjects. Normally perfused segments of ICM did not differ (p = 0.33). ICM patients had a left ventricular ejection fraction (LVEF) of 25 ± 12%, 25/353 mismatched, and 46/353 matched defect segments. 82 Rb washout was higher in hypoperfused vs normal segments (p 82 Rb washout correlated inversely with 82 Rb uptake (r = -0.70; p 82 Rb washout does not distinguish between perfusion/metabolism patterns of hibernating myocardium and scar. Tissue integrity may be at least partially impaired in hibernation. (orig.)

  7. LPS from bovine serum albumin drives TNF-α release during ex-vivo placenta perfusion experiments, contaminates the perfusion system but can be effectively removed by oxidative cleaning.

    Science.gov (United States)

    Vasanthan, T; Rochow, N; Mian, F; Codini, T; DeFrance, B; Fusch, G; Samiee-Zafarghandy, S; Fusch, C

    2014-12-01

    The dual ex-vivo perfusion of human placental tissue is useful to study inflammatory pathways. We found significant TNF-α release in negative controls similar in concentration to lipopolysaccharide (LPS) stimulated placentas. The aim of the current study was to (i) identify sources driving TNF-α release and (ii) develop an approach to control for it. (i) To determine sources leading to TNF-α release, solutions frequently circulated through the perfusion system and perfusion media with different bovine serum albumin (BSA) quality were exposed to mouse macrophage cell lines (RAW264.7) and subsequently measured for TNF-α expression. (ii) To assess memory effects and validate cleaning procedures, sham perfusion experiments were conducted either in the presence or absence of exogenous LPS, in new tubing that was contaminated, cleaned and analyzed for the effectiveness of LPS removal. Oxidative and acid-base cleaning were tested for their effectiveness to reduce LPS contamination. TNF-α release, observed in negative control experiments, was attributed to the use of LPS-contaminated BSA as well as inadequate cleaning of the perfusion system. Once introduced in the perfusion system, LPS accumulated and created a memory effect. Oxidative but not acid-base depyrogenation effectively reduced LPS levels to concentrations that were in accordance with FDA guidelines (placenta perfusion model could have confounding effects on experimental outcomes leading to misinterpretation of data. To circumvent LPS contamination LPS-free BSA and oxidative depyrogenation cleaning techniques should be implemented in future placental perfusion studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Brain Perfusion Changes in Intracerebral Hemorrhage

    International Nuclear Information System (INIS)

    Mititelu, R.; Mazilu, C.; Ghita, S.; Rimbu, A.; Marinescu, G.; Codorean, I.; Bajenaru, O.

    2006-01-01

    Full text: Purpose: Despite the latest advances in medical treatment and neuro critical care, patients suffering spontaneous intracerebral hemorrhage (SICH) still have a very poor prognosis, with a greater mortality and larger neurological deficits at the survivors than for ischemic stroke. Many authors have shown that there are many mechanisms involved in the pathology of SICH: edema, ischemia, inflammation, apoptosis. All of these factors are affecting brain tissue surrounding hematoma and are responsible of the progressive neurological deterioration; most of these damages are not revealed by anatomical imaging techniques. The aim of our study was to asses the role of brain perfusion SPECT in demonstrating perfusion changes in SICH patients. Method: 17 SICH pts were studied. All pts underwent same day CT and brain SPECT with 99mTcHMPAO, 24h-5d from onset of stroke. Results: 14/17 pts showed a larger perfusion defect than expected after CT. In 2 pts hematoma diameter was comparable on CT and SPECT; 1pt had quasinormal aspect of SPECT study. In pts with larger defects, SPECT revealed a large cold spot with similar size compared with CT, and a surrounding hypo perfused area. 6/17 pts revealed cortical hyper perfusion adjacent to hypo perfused area and corresponding to a normal-appearing brain tissue on CT. In 3 pts we found crossed cerebellar diaskisis.In 2 pts we found cortical hypo perfused area in the contralateral cortex, with normal appearing brain tissue on CT. Conclusions: Brain perfusion SPECT revealed different types of perfusion changes in the brain tissue surrounding hematoma. These areas contain viable brain tissue that may be a target for future ne uroprotective strategies. Further studies are definitely required to demonstrate prognostic significance of these changes, but we can conclude that brain perfusion SPECT can play an important role in SICH, by early demonstrating functional changes responsible of clinical deterioration, thus allowing prompt

  9. A novel microthermal probe for the measurement of perfusion

    Science.gov (United States)

    Yi, Ming; Kausik, Aditya; Podhajsky, Ronald J.; Mahajan, Roop L.

    2009-02-01

    Using micro-fabrication techniques a micro thermal probe has been developed in our laboratory to measure the thermal conductivity of biological tissues. This paper presents our latest experimental results which demonstrate the usefulness of the micro thermal probe in mapping the complicated perfusion field inside biological tissues. A perfused pig liver model has been constructed to simulate in vivo conditions. The portal vein and hepatic artery of a porcine liver were intubated and connected to a perfusion circuit. Saline water was perfused through the liver driven by a peristaltic pump. By varying the pumping rate of the perfused model, we measured the effective thermal conductivity at different perfusion rates in different locations. The results show that the effective thermal conductivity varies with the square root of the perfusion rate. Also, by rotating the micro probes, we observed a strong directional dependence of the effective thermal conductivity, revealing that perfusion is not a scalar but a vector field.

  10. Effects of Two Different Exogenous Surfactant Preparations on Serial Peripheral Perfusion Index and Tissue Carbon Monoxide Measurements in Preterm Infants with Severe Respiratory Distress Syndrome

    Directory of Open Access Journals (Sweden)

    Demet Terek

    2015-08-01

    Conclusion: Patients with RDS had poor perfusion, and PI improved with both surfactant preparations only following a short decline in the 1st minute. The expected improvement of PI occurred earlier in the beractant subgroup. TCO declined in both groups, showing lung improvement and decreased oxidative/inflammatory stress, and it was normalized earlier with poractant alfa.

  11. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...... and represents a supplement and alternative to animal testing, bypassing the animal to human extrapolation. Placentas are readily obtainable from most births upon informed consent from the mothers and are considered a promising tissue alternative/supplement to animal experiments. The system is validated...... as a part of work package 2 of the integrated project ReProTect....

  12. Washout of {sup 82}Rb as a marker of impaired tissue integrity, obtained by list-mode cardiac PET/CT: relationship with perfusion/metabolism patterns of myocardial viability

    Energy Technology Data Exchange (ETDEWEB)

    Chien, David T.; Bravo, Paco; Higuchi, Takahiro; Merrill, Jennifer [Johns Hopkins University School of Medicine, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Bengel, Frank M. [Johns Hopkins University School of Medicine, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany)

    2011-08-15

    Myocardial washout of the potassium analogue {sup 82}Rb may indicate tissue impairment. Few studies have evaluated its usefulness for viability assessment, and controversial results were reported. We revisited this topic using list-mode positron emission tomography (PET)/CT. A total of 22 patients with chronic ischemic cardiomyopathy (ICM) and 11 control subjects with normal CT coronary angiogram were studied. Rest {sup 82}Rb PET/CT studies were acquired in list mode and resampled to static, gated, and dynamic images. Using a 17-segment model, {sup 82}Rb washout was determined by monoexponential fitting of myocardial time-activity curves. In ICM patients, {sup 18}F-fluorodeoxyglucose (FDG) studies were obtained in the same session and segments were classified as normally perfused, mismatch, or matched defect. {sup 82}Rb washout was minimal and homogeneous in control subjects. Normally perfused segments of ICM did not differ (p = 0.33). ICM patients had a left ventricular ejection fraction (LVEF) of 25 {+-} 12%, 25/353 mismatched, and 46/353 matched defect segments. {sup 82}Rb washout was higher in hypoperfused vs normal segments (p < 0.05), but not different between mismatch and matched defect (p = 0.18). Intraindividual analysis in nine patients showing both FDG mismatch and matched defect confirmed absence of differences. Overall, segmental {sup 82}Rb washout correlated inversely with {sup 82}Rb uptake (r = -0.70; p < 0.05) and less well with FDG uptake (r = -0.31; p < 0.05). Using state-of-the-art PET/CT technology for myocardial viability assessment, {sup 82}Rb washout does not distinguish between perfusion/metabolism patterns of hibernating myocardium and scar. Tissue integrity may be at least partially impaired in hibernation. (orig.)

  13. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... the contrastagent concentration, [Ca], and the changes in R2 or R 2 has been questioned. In this thesis, an MRI scanner sequence for detection of the longitudinal relaxation rate, R1 during bolus passage was modied for brain perfusion measurements, since the linearity between the changes in R1 and [Ca] is expected...... to be more robust. Successful brain perfusion quantication based on R1 weighted signals has not previously been reported, due to the poor signal to noise ratio of the images. Initial experiments reported in this thesis show that improved sequence may provide more accurate perfusion estimates in the brain...

  14. CT Perfusion of the Head

    Science.gov (United States)

    ... Site Index A-Z CT Perfusion of the Head Computed tomography (CT) perfusion of the head uses ... the Head? What is CT Perfusion of the Head? Computed tomography (CT) perfusion imaging shows which areas ...

  15. Improved visualization of delayed perfusion in lung MRI

    International Nuclear Information System (INIS)

    Risse, Frank; Eichinger, Monika; Kauczor, Hans-Ulrich; Semmler, Wolfhard; Puderbach, Michael

    2011-01-01

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S n,max normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement τ to visualize regions with delayed bolus onset; and (3) ratio R = S n,max /τ was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  16. Effects of Two Different Exogenous Surfactant Preparations on Serial Peripheral Perfusion Index and Tissue Carbon Monoxide Measurements in Preterm Infants with Severe Respiratory Distress Syndrome.

    Science.gov (United States)

    Terek, Demet; Gonulal, Deniz; Koroglu, Ozge Altun; Yalaz, Mehmet; Akisu, Mete; Kultursay, Nilgun

    2015-08-01

    Administration of an exogenous surfactant may affect both ventilatory and hemodynamic parameters in preterm infants with respiratory distress syndrome (RDS). Peripheral perfusion may be expected to be influenced, and serial perfusion index (PI) values may show this effect. Noninvasive transcutaneous carbon monoxide (TCO) monitoring may show RDS severity, oxidative and inflammatory stress, and response to surfactant treatment. This randomized controlled nonblinded study was performed in 30 preterm infants with RDS, treated with poractant alfa (n = 15) or beractant (n = 15); 18 preterm infants without RDS served as a control group. Oxygenation and hemodynamic parameters were recorded and compared through the first 6 hours of treatment. PI and TCO values were measured prior to (Tp), immediately after (T0), and at 5 minutes (T5), 30 minutes (T30), 60 minutes (T60), and 360 minutes (T360) after the bolus surfactant administration. The mean arterial pressure, oxygenation index, pH, and lactate levels were recorded simultaneously. Both study groups had lower Tp PI and higher Tp TCO levels than controls. Both surfactant preparations improved the PI, TCO, mean arterial pressure, oxygenation index, pH, and lactate levels at the end point of T360. However, the median Tp PI value of 1.3 first decreased to 0.86 at T0 (P < 0.001), and then it increased to 0.99 at T5 (p < 0.001) and to 1.25 at T30 (p = 0.037). The median Tp TCO value of 3 decreased to 2, 1.5, 0, and 0 at T0, T5, T30, and T60, respectively (p < 0.001). PI more quickly recovered to Tp values (30 minutes vs. 60 minutes) and reached the control group values (30 minutes vs. 360 minutes) with beractant compared to that with poractant alfa. TCO recovered to Tp values in both groups at the same time (5 minutes vs. 5 minutes), but reached the control group values more quickly (5 minutes vs. 30 minutes) with poractant alfa than with beractant. Patients with RDS had poor perfusion, and PI improved with both surfactant

  17. The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: How can we minimize the risk for deterministic effects?

    Energy Technology Data Exchange (ETDEWEB)

    Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Papadakis, Antonios E.; Damilakis, John [Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete (Greece); Medical Diagnostic Center ' Ayios Therissos,' P.O. Box 28405, Nicosia 2033, Cyprus and Department of Medical Physics, Medical School, Democritus University of Thrace, Panepistimioupolis, Dragana 68100, Alexandroupolis (Greece); Department of Medical Physics, University Hospital of Heraklion, P.O. Box 1352, Heraklion 71110, Crete (Greece); Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete (Greece)

    2013-01-15

    Purpose: To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses. Methods: The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. Results: The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of

  18. The effect of head size∕shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: how can we minimize the risk for deterministic effects?

    Science.gov (United States)

    Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Papadakis, Antonios E; Damilakis, John

    2013-01-01

    To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size∕shape, head position during the examination and bowtie filter used on peak tissue doses. The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size∕shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal-to-noise ratio

  19. In vivo assessment of myocardial viability after acute myocardial infarction: A head-to-head comparison of the perfusable tissue index by PET and delayed contrast-enhanced CMR.

    Science.gov (United States)

    Timmer, Stefan A J; Teunissen, Paul F A; Danad, Ibrahim; Robbers, Lourens F H J; Raijmakers, Pieter G H M; Nijveldt, Robin; van Rossum, Albert C; Lammertsma, Adriaan A; van Royen, Niels; Knaapen, Paul

    2017-04-01

    Early recognition of viable myocardium after acute myocardial infarction (AMI) is of clinical relevance, since affected segments have the potential of functional recovery. Delayed contrast-enhanced magnetic resonance imaging (DCE-CMR) has been validated extensively for the detection of viable myocardium. An alternative parameter for detecting viability is the perfusable tissue index (PTI), derived using [ 15 O]H 2 O positron emission tomography (PET), which is inversely related to the extent of myocardial scar (non-perfusable tissue). The aim of the present study was to investigate the predictive value of PTI on recovery of LV function as compared to DCE-CMR in patients with AMI, after successful percutaneous coronary intervention (PCI). Thirty-eight patients with ST elevation myocardial infarction (STEMI) successfully treated by PCI were prospectively recruited. Subjects were examined 1 week and 3 months (mean follow-up time: 97 ± 10 days) after AMI using [ 15 O]H 2 O PET and DCE-CMR to assess PTI, regional function and scar. Viability was defined as recovery of systolic wall thickening ≥3.0 mm at follow-up by use of CMR. A total of 588 segments were available for serial analysis. At baseline, 180 segments were dysfunctional and exhibited DCE. Seventy-three (41%) of these dysfunctional segments showed full recovery during follow-up (viable), whereas 107 (59%) segments remained dysfunctional (nonviable). Baseline PTI of viable segments was 0.94 ± 0.09 and was significantly higher compared to nonviable segments (0.80 ± 0.13, P myocardial viability shortly after reperfused AMI is feasible using PET. PET-derived PTI yields a good predictive value for the recovery of LV function in PCI-treated STEMI patients, in excellent agreement with DCE-CMR.

  20. MRI of pulmonary perfusion; MRT der Lungenperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Fink, C. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany). Institut fuer Klinische Radiologie; Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie, Heidelberg (Germany); Risse, F.; Semmler, W. [Deutsches Krebsforschungszentrum (DKFZ), Abteilung Medizinische Physik in der Radiologie, Heidelberg (Germany); Schoenberg, S.O.; Reiser, M.F. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany). Institut fuer Klinische Radiologie; Kauczor, H.-U. [Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie, Heidelberg (Germany)

    2006-04-15

    Lung perfusion is a crucial prerequisite for effective gas exchange. Quantification of pulmonary perfusion is important for diagnostic considerations and treatment planning in various diseases of the lungs. Besides disorders of pulmonary vessels such as acute pulmonary embolism and pulmonary hypertension, these also include diseases of the respiratory tract and lung tissue as well as pulmonary tumors. This contribution presents the possibilities and technical requirements of MRI for diagnostic work-up of pulmonary perfusion. (orig.) [German] Die Perfusion der Lunge ist eine entscheidende Voraussetzung fuer einen effektiven Gasaustausch. Die Bestimmung der Lungenperfusion ist bei verschiedenen Erkrankungen der Lunge fuer Diagnostik und Therapieplanung bedeutsam. Hierzu zaehlen neben Erkrankungen der Lungengefaesse wie akute Lungenembolie und pulmonale Hypertension ebenso Erkrankungen der Atemwege, des Lungengeruests und Lungentumoren. In diesem Beitrag werden die Moeglichkeiten und technischen Voraussetzungen der MRT zur Diagnostik der Lungenperfusion dargestellt. (orig.)

  1. Histamine combined with melphalan in isolated limb perfusion for the treatment of locally advanced soft tissue sarcomas: preclinical studies in rats Histamina combinada ao melfalano na perfusão de membro isolado para o tratamento de sarcomas de partes moles localmente avançado: estudos pré-clínicos em ratos

    Directory of Open Access Journals (Sweden)

    Flavia Brunstein

    2005-08-01

    Full Text Available PURPOSE: To evaluate the potential benefit of histamine combined with melphalan in the isolated limb perfusion (ILP as an alternative to TNF-alfa and melphalan combination, for the treatment of irressectable soft tissue sarcomas of the limbs in Brown Norway (BN rats. METHODS: 20 BN rats had small fragments of syngeneic BN-175 fibosarcoma inserted on the right hind limb. In 7-10 days the tumor reached a median diameter of 12-15 mm and they were randomly divided in four groups (sham, melphalan, histamine and escalating doses of histamine combined to melphalan being submitted to experimental ILP for 30 minutes. Tumors were measured daily with a caliper and the volume was calculated. RESULTS: Response curves showed a significant effect of the combination of histamine 200 mg/mL with melphalan, with 66% overall response, including 33% complete responses (pOBJETIVO: Avaliar o potencial benéfico da histamina combinada ao melfalano, na perfusão de membro isolado (PMI, como alternativa à combinação TNF-alfa mais melfalano, no tratamento de sarcomas de partes moles irressecaveis em extremidades, em ratos de linhagem Brown Norway (BN. MÉTODOS: 20 ratos BN foram submetidos a implantação de fragmentos de fibrosarcoma singênico BN-175 na pata traseira direita. Em cerca de 7-10 dias o tumor atingiu um diâmetro médio de 12-15 mm e foram aleatóriamente divididos em quatro grupos (controle, melfalano, histamina em doses progessivas combinada ao melfalano e histamina sendo submetidos a PMI experimental por 30 minutos. Os tumores foram então medidos diariamente com o uso de paquímetro e o volume tumoral calculado. RESULTADOS: As curvas de resposta mostram um efeito significativo da combinação de Histamina na concentração de 200 mg/mL ao melfalano, com 66% de resposta global incluindo 33% de respostas completas (p < 0.01. Não houve efeitos colaterais sistêmicos e localmente apenas edema leve e transitório nos animais tratados com histamine

  2. Do you mind if I vape? Immediate effects of electronic cigarettes on perfusion in buccal mucosal tissue--a pilot study.

    Science.gov (United States)

    Reuther, William J; Hale, Beverley; Matharu, Jas; Blythe, John N; Brennan, Peter A

    2016-04-01

    The association between smoking and postoperative complications is compounded in patients who have oral and maxillofacial operations by an additional local effect, and patients often continue to smoke after operation despite advice to stop. Recent studies have suggested that nicotine may reduce inflammation and improve angiogenesis, so topical application may be beneficial for smokers. The electronic cigarette is increasing in popularity and more patients ask whether they can vape after operation. We investigated the effect of electronic cigarettes (of which half contained nicotine and half did not) on blood flow in the buccal mucosa in 10 volunteers immediately after vaping. Smokers were excluded as this was considered an additional variable in a small pilot study and our Trust has a no-smoking policy. After vaping for 5 minutes, capillary blood flow was measured in the buccal mucosa at 5-minute intervals using a laser Doppler probe, and the results were expressed as arbitrary perfusion units. There was a wide variation in results and a small but significant rise (p=0.008) as a result of nicotine vaping, but these fell to the same levels as before within 30 minutes. Electronic cigarettes may have an effect on blood flow to the oral mucosa, although further studies are needed to show whether they improve healing time after operation. Additional work is also needed to compare them with cigarettes. Copyright © 2016. Published by Elsevier Ltd.

  3. Isolated limb perfusion: what is the evidence for its use?

    NARCIS (Netherlands)

    Noorda, Eva M.; Vrouenraets, Bart C.; Nieweg, Omgo E.; van Coevorden, Frits; Kroon, Bin B. R.

    2004-01-01

    BACKGROUND: This study was conducted to assess the best available evidence for the use of isolated limb perfusion. METHODS: Following the principles of Evidence-Based Medicine, we reviewed the best available evidence for isolated limb perfusion (ILP) for melanoma and soft tissue sarcoma (STS) of the

  4. Italian retail gasoline activities: inadequate distribution network

    International Nuclear Information System (INIS)

    Verde, Stefano

    2005-01-01

    It is common belief that competition in the Italian retail gasoline activities is hindered by oil companies' collusive behaviour. However, when developing a broader analysis of the sector, low efficiency and scarce competition could results as the consequences coming from an inadequate distribution network and from the recognition of international markets and focal point [it

  5. Barriers to Mammography among Inadequately Screened Women

    Science.gov (United States)

    Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

    2015-01-01

    Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

  6. Radiologists' responses to inadequate referrals

    Energy Technology Data Exchange (ETDEWEB)

    Lysdahl, Kristin Bakke [Oslo University College, Faculty of Health Sciences, Oslo (Norway); University of Oslo, Section for Medical Ethics, Faculty of Medicine, P.O. Box 1130, Blindern, Oslo (Norway); Hofmann, Bjoern Morten [University of Oslo, Section for Medical Ethics, Faculty of Medicine, P.O. Box 1130, Blindern, Oslo (Norway); Gjoevik University College, Faculty of Health Care and Nursing, Gjoevik (Norway); Espeland, Ansgar [Haukeland University Hospital, Department of Radiology, Bergen (Norway); University of Bergen, Section for Radiology, Department of Surgical Sciences, Bergen (Norway)

    2010-05-15

    To investigate radiologists' responses to inadequate imaging referrals. A survey was mailed to Norwegian radiologists; 69% responded. They graded the frequencies of actions related to referrals with ambiguous indications or inappropriate examination choices and the contribution of factors preventing and not preventing an examination of doubtful usefulness from being performed as requested. Ninety-five percent (344/361) reported daily or weekly actions related to inadequate referrals. Actions differed among subspecialties. The most frequent were contacting the referrer to clarify the clinical problem and checking test results/information in the medical records. Both actions were more frequent among registrars than specialists and among hospital radiologists than institute radiologists. Institute radiologists were more likely to ask the patient for additional information and to examine the patient clinically. Factors rated as contributing most to prevent doubtful examinations were high risk of serious complications/side effects, high radiation dose and low patient age. Factors facilitating doubtful examinations included respect for the referrer's judgment, patient/next-of-kin wants the examination, patient has arrived, unreachable referrer, and time pressure. In summary, radiologists facing inadequate referrals considered patient safety and sought more information. Vetting referrals on arrival, easier access to referring clinicians, and time for radiologists to handle inadequate referrals may contribute to improved use of imaging. (orig.)

  7. Financial incentives are inadequate for most companies

    Indian Academy of Sciences (India)

    Financial incentives are inadequate for most companies. market far less lucrative than for other diseases, which results in chronic underinvestment; reduced investment in TB drug R&D,. Pfizer withdrawal from TB R&D; AstraZeneca abandon TB R&D & close site; Novartis pull out; 4/22 Big Pharma producing antibacterials ...

  8. Standardized perfusion value of the esophageal carcinoma and its correlation with quantitative CT perfusion parameter values

    Energy Technology Data Exchange (ETDEWEB)

    Djuric-Stefanovic, A., E-mail: avstefan@eunet.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Saranovic, Dj., E-mail: crvzve4@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Sobic-Saranovic, D., E-mail: dsobic2@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia); Masulovic, D., E-mail: draganmasulovic@yahoo.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Artiko, V., E-mail: veraart@beotel.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia)

    2015-03-15

    Purpose: Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Methods: Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (r{sub S}). Results: Median SPV of the esophageal carcinoma (7.1; range: 2.8–13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4–2.4), (Z = −5.511, p < 0.001). The cut-off value of the SPV of 2.5 enabled discrimination of esophageal cancer from the skeletal muscle with sensitivity and specificity of 100%. SPV of the esophageal carcinoma significantly correlated with corresponding tumor BF (r{sub S} = 0.484, p = 0.002), BV (r{sub S} = 0.637, p < 0.001) and PS (r{sub S} = 0.432, p = 0.005), and SPV of the skeletal muscle significantly correlated with corresponding muscle BF (r{sub S} = 0.573, p < 0.001), BV (r{sub S} = 0.849, p < 0.001) and PS (r{sub S} = 0.761, p < 0.001). Conclusions: We presented a database of the SPV for the esophageal cancer and proved that SPV of the esophageal neoplasm significantly differs from the SPV of the skeletal muscle, which represented a sample of healthy

  9. Transplacental transfer of monomethyl phthalate and mono(2-ethylhexyl) phthalate in a human placenta perfusion system

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E; Hedegaard, Morten

    2007-01-01

    The transplacental passage of monomethylphtalate (mMP) and mono (2-ethylhexyl) phthalate (mEHP) was studied using an ex vivo placental perfusion model with simultaneous perfusion of fetal and maternal circulation in a single cotyledon. Umbilical cord blood and placental tissue collected both before...... and after perfusion were also analyzed. Placentas were obtained immediately after elective cesarean section and dually perfused in a recirculation system. mMP or mEHP was added to maternal perfusion medium to obtain concentrations at 10 and 25 microg/L, respectively. The placental transfer was followed...... analyzing samples from fetal and maternal perfusion media by liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). Four perfusions with mMP indicated a slow transplacental transfer, with a feto-maternal ratio (FM ratio) of 0.30 +/- 0.03 after 150 min of perfusion. Four perfusions with m...

  10. Dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C.

    2011-01-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  11. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  12. Evidence Report: Risk Factor of Inadequate Nutrition

    Science.gov (United States)

    Smith, Scott M.; Zwart, Sara R.; Heer, Martina

    2015-01-01

    The importance of nutrition in exploration has been documented repeatedly throughout history, where, for example, in the period between Columbus' voyage in 1492 and the invention of the steam engine, scurvy resulted in more sailor deaths than all other causes of death combined. Because nutrients are required for the structure and function of every cell and every system in the body, defining the nutrient requirements for spaceflight and ensuring provision and intake of those nutrients are primary issues for crew health and mission success. Unique aspects of nutrition during space travel include the overarching physiological adaptation to weightlessness, psychological adaptation to extreme and remote environments, and the ability of nutrition and nutrients to serve as countermeasures to ameliorate the negative effects of spaceflight on the human body. Key areas of clinical concern for long-duration spaceflight include loss of body mass (general inadequate food intake), bone and muscle loss, cardiovascular and immune system decrements, increased radiation exposure and oxidative stress, vision and ophthalmic changes, behavior and performance, nutrient supply during extravehicular activity, and general depletion of body nutrient stores because of inadequate food supply, inadequate food intake, increased metabolism, and/or irreversible loss of nutrients. These topics are reviewed herein, based on the current gap structure.

  13. Increasing heel skin perfusion by elevation.

    Science.gov (United States)

    Huber, Jacqueline; Reddy, Raj; Pitham, Tom; Huber, David

    2008-01-01

    To determine the efficacy of elevation in the primary prevention and treatment of pressure ulcers by studying the blood flow in tissue at risk of ulceration. A prospective study was used to compare different preventative devices with an elevating prosthesis. : Wollongong Hospital Wollongong, New South Wales, Australia. Normal subjects and subjects with vasculopathy were tested with their heel resting on a hospital bed, medical-grade lamb's wool, or a viscoelastic gel overlay, with or without the test prosthesis. Skin perfusion was measured throughout using a laser Doppler monitor. A device designed to elevate the heel off the bed and distribute the weight of the leg and foot on the calf. Heel capillary blood perfusion. Perfusion in the heel was significantly greater when elevated than when using the other devices tested. The differences in mean red blood cell flux were significant, with P pressure ulcer prevention and treatment and should be incorporated into health care practice.

  14. CT-based Techniques for Brain Perfusion.

    Science.gov (United States)

    Krishnan, Pradeep; Murphy, Amanda; Aviv, Richard I

    2017-06-01

    Recent rapid advances in endovascular treatment for acute ischemic stroke highlight the crucial role of neuroimaging especially multimodal computed tomography (CT) including CT perfusion in stroke triage and management decisions. With an increasing focus on changes in cerebral physiology along with time-based matrices in clinical decisions for acute ischemic stroke, CT perfusion provides a rapid and practical modality for assessment and identification of salvageable tissue at risk and infarct core and provides a better understanding of the changes in cerebral physiology. Although there are challenges with the lack of standardization and accuracy of quantitative assessment, CT perfusion is evolving as a cornerstone for imaging-based strategies in the rapid management of acute ischemic stroke.

  15. MRI of myocardial perfusion.

    Science.gov (United States)

    Jerosch-Herold, Michael; Muehling, Olaf; Wilke, Norbert

    2006-02-01

    An overwhelming number of myocardial perfusion studies are done by nuclear isotope imaging. Magnetic resonance imaging during the first pass of an injected, contrast bolus has some significant advantages for detection of blood flow deficits, namely higher spatial resolution, absence of ionizing radiation, and speed of the test. Previous clinical studies have demonstrated that excellent sensitivity and specificity can be achieved with MR myocardial perfusion imaging for detecting coronary artery disease, and assessment of patients with acute chest pain. Furthermore, an absolute quantification of myocardial blood flow is feasible, as was demonstrated by comparison of MR perfusion imaging, to measurements with isotope labeled microspheres in experimental models. An integrated assessment of perfusion, function, and viability, is thus feasible by MRI to answer important clinical challenges such as the identification of stunned or hibernating, but viable myocardium.

  16. Measuring myocardial perfusion

    DEFF Research Database (Denmark)

    Qayyum, A A; Kastrup, J

    2015-01-01

    Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion......-known and is used in routine clinical practice. However, PET uses radioactive tracers and has a lower spatial resolution compared to CMR and CT. CMR and CT are emerging techniques in the field of myocardial perfusion imaging. CMR uses magnetic resonance to obtain images, whereas CT uses x-rays during first....... Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well...

  17. A compact instrument to measure perfusion of vasculature in transplanted maxillofacial free flaps

    Science.gov (United States)

    Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Podolsky, Matthew J.; Farkas, Dana; Ward, Brent B.; Vartarian, Mark; Feinberg, Stephen E.; Lee, Seung Yup; Parikh, Urmi; Mycek, Mary-Ann; Christian, James F.

    2016-03-01

    The vascularization and resulting perfusion of transferred tissues are critical to the success of grafts in buried free flap transplantations. To enable long-term clinical monitoring of grafted tissue perfusion during neovascularization and endothelialization, we are developing an implantable instrument for the continuous monitoring of perfusion using diffuse correlation spectroscopy (DCS), and augmented with diffuse reflectance spectroscopy (DRS). This work discusses instrument construction, integration, and preliminary results using a porcine graft model.

  18. Skull-base Osteomyelitis: a Dreaded Complication after Trivial Fall and Inadequate Management

    Directory of Open Access Journals (Sweden)

    Kundan Mittal

    2015-10-01

    Full Text Available Introduction: Skull-based osteomyelitis is bony infection which generally originates from inadequately treated chronic infection, adjoining tissue infection or after trauma.Case: 11 month female child had a trivial fall while standing near a bucket. The child developed fracture of right clavicle and left orbital swelling which was inadequately treated. This resulted in in spread of infection to adjoining tissues, skull bones, sinuses and brain.Conclusion: Cranial base osteomyelitis is rare but dreaded condition which requires early diagnosis and prompt treatment to avoid mortality and morbidity in form of neurological deficits and permanent disability

  19. Hepatic perfusion changes in an experimental model of acute pancreatitis: Evaluation by perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Tutcu, Semra [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Serter, Selim, E-mail: serterselim@gmail.co [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Kaya, Yavuz; Kara, Eray [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Nese, Nalan [Department of Pathology, Celal Bayar University, School of Medicine, Manisa (Turkey); Pekindil, Goekhan [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Coskun, Teoman [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey)

    2010-08-15

    Purpose: It is known that acute pancreatitis may cause secondary changes in several organs. Liver is one of these involved organs. In different experimental studies hepatic damages were shown histopathologically in acute pancreatitis but there are a few studies about perfusion disorders that accompany these histopathologic changes. Perfusion CT (pCT) provides the ability to detect regional and global alterations in organ blood flow. The purpose of the study was to describe hepatic perfusion changes in experimental acute pancreatitis model with pCT. Materials and methods: Forty Sprague-Dawley rats of both genders with average weights of 250 g were used. Rats were randomized into two groups. Twenty rats were in control group and 20 in acute pancreatitis group. pCT was performed. Perfusion maps were formed by processing the obtained images with perfusion CT software. Blood flow (BF) and blood volume (BV) values were obtained from these maps. All pancreatic and liver tissues were taken off with laparotomy and histopathologic investigation was performed. Student's t test was used for statistical analyses. Results: In pCT we found statistically significant increase in blood volume in both lobes of liver and in blood flow in right lobe of the liver (p < 0.01). Although blood flow in left lobe of the liver increased, it did not reach statistical significance. Conclusion: The quantitative analysis of liver parenchyma with pCT showed that acute pancreatitis causes a significant perfusion changes in the hepatic tissue. Systemic mediators seem to be effective as well as local inflammatory changes in perfusion changes.

  20. Basic consideration of diffusion/perfusion imaging

    International Nuclear Information System (INIS)

    Tamagawa, Yoichi; Kimura, Hirohiko; Matsuda, Tsuyoshi; Kawamura, Yasutaka; Nakatsugawa, Shigekazu; Ishii, Yasushi; Sakuma, Hajime; Tsukamoto, Tetsuji.

    1990-01-01

    In magnetic resonance imaging (MRI), microscopic motion of biological system such as molecular diffusion of water and microcirculation of blood in the capillary network (perfusion) has been proposed to cause signal attenuation as an intravoxel incoherent motion (IVIM). Quantitative imaging of the IVIM phenomenon was attempted to generate from a set of spin-echo (SE) sequences with or without sensitization by motion probing gradient (MPG). The IVIM imaging is characterized by a parameter, apparent diffusion coefficient (ADC), which is an integration of both the diffusion and the perfusion factor on voxel-by-voxel basis. Hard ware was adjusted to avoid image artifact mainly produced by eddy current. Feasibility of the method was tested using bottle phantom filled with water at different temperature and acetone, and the calculated ADC values of these media corresponded well with accepted values of diffusion. The method was then applied to biological system to investigate mutual participation of diffusion/perfusion on the ADC value. The result of tumor model born on nude mouse suggested considerable participation of perfusion factor which immediately disappeared after sacrificing the animal. Meanwhile, lower value of sacrificed tissue without microcirculation was suggested to have some restriction of diffusion factor by biological tissue. To substantiate the restriction effect on the diffusion, a series of observation have made on a fiber phantom, stalk of celory with botanical fibers and human brain with nerve fibers, in applying unidirectional MPG along the course of these banch of fiber system. The directional restriction effect of diffusion along the course of fiber (diffusion anisotrophy) was clearly visualized as directional change of ADC value. The present method for tissue characterization by diffusion/perfusion on microscopic level will provide a new insight for evaluation of functional derangement in human brain and other organs. (author)

  1. Improvement of resolution in detection of 3D-functional structures in isolated perfused pig heart

    Science.gov (United States)

    Rauh, Robert; Hiller, Michael; Trinks, Tobias; Kessler, Manfred D.

    2001-10-01

    Subcellular structures play a decisive role in light scattering properties of tissue. Our recent efforts aimed at monitoring these structures by use of micro lightguides and scanning tissue spectroscopy technique (EMPHO II SSK) at isolated perfused organs. With application of 70micrometers lightguides at an isolated perfused pig heart model we were able to improve the resolution to a step size of 20micrometers .

  2. CT Perfusion Characteristics Identify Metastatic Sites in Liver

    Directory of Open Access Journals (Sweden)

    Yuan Wang

    2015-01-01

    Full Text Available Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF, blood volume (BV, mean transit time (MTT, permeability (PS, and hepatic arterial fraction (HAF, for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  3. CT Perfusion Characteristics Identify Metastatic Sites in Liver.

    Science.gov (United States)

    Wang, Yuan; Hobbs, Brian P; Ng, Chaan S

    2015-01-01

    Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT) perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF), blood volume (BV), mean transit time (MTT), permeability (PS), and hepatic arterial fraction (HAF), for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  4. Automatic extraction of left ventricle in SPECT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Liu Li; Zhao Shujun; Yao Zhiming; Wang Daoyu

    1999-01-01

    An automatic method of extracting left ventricle from SPECT myocardial perfusion data was introduced. This method was based on the least square analysis of the positions of all short-axis slices pixels from the half sphere-cylinder myocardial model, and used a iterative reconstruction technique to automatically cut off the non-left ventricular tissue from the perfusion images. Thereby, this technique provided the bases for further quantitative analysis

  5. Separation of myoglobin and hemoglobin in isolated perfused pig heart

    Science.gov (United States)

    Rauh, Robert; Hiller, Michael; Trinks, Tobias; Kessler, Manfred D.

    2001-10-01

    For the quantitative determination of hemoglobin concentration in heart muscle it is important to distinguish between myoglobin and hemoglobin, two dyes with very similar optical absorption properties. With an isolated perfused pig heart model and EMPHO II SSK we measured tissue spectra in the visible range before and after adding erythrocytes to the perfusate. By calculating light intensity differences we were able to show spatial hemoglobin distribution in heart muscle.

  6. 9 CFR 417.6 - Inadequate HACCP Systems.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Inadequate HACCP Systems. 417.6... ANALYSIS AND CRITICAL CONTROL POINT (HACCP) SYSTEMS § 417.6 Inadequate HACCP Systems. A HACCP system may be found to be inadequate if: (a) The HACCP plan in operation does not meet the requirements set forth in...

  7. Effect of inspiratory oxygen fraction and perfusion pressure on 3D functional structures during hypoxia and reoxygenation in isolated perfused pig heart

    Science.gov (United States)

    Rauh, Robert; Boehnert, Markus; Kessler, Manfred D.

    2001-05-01

    Subcellular structures are mainly responsible for light scattering in tissue. Since these structures change their outer shape during hypoxia, backscattered light intensity should be useful in monitoring of tissue in hypoxic or ischemic situations. In a new model of isolated perfused pig heart we investigated the relation between three-dimensional functional structures caused by tissue light scattering and the perfusion pressure during reoxygenation after hypoxia. By use of EMPHO-Oxyscan we could see that there is a clear relation between the perfusion pressure and the level of 3D structures. At very low perfusion pressures there is a delay in recovery of myocardium. Increase in perfusion pressure accelerates the recovery. With functional 3D images created by use of EMPHO-Oxyscan, we now have an instrument for depicting these processes. This technique will be useful in clinical monitoring in cardiac surgery, intraoperative as well as postoperative.

  8. Towards robust deconvolution of low-dose perfusion CT: Sparse perfusion deconvolution using online dictionary learning

    Science.gov (United States)

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C.

    2014-01-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain. PMID:23542422

  9. Inadequate Nutritional Status of Hospitalized Cancer Patients

    Directory of Open Access Journals (Sweden)

    Ali Alkan

    2017-03-01

    Full Text Available Objective: In oncology practice, nutrition and also metabolic activity are essential to support the nutritional status and prevent malignant cachexia. It is important to evaluate the patients and plan the maneuvers at the start of the therapy. The primary objective of the study is to define the nutritional status of hospitalized patients and the factors affecting it in order to define the most susceptible patients and maneuvers for better nutritional support. Methods: Patients hospitalized in oncology clinic for therapy were evaluated for food intake and nutritional status through structured interviews. The clinical properties, medical therapies, elements of nutritional support were noted and predictors of inadequate nutritional status (INS were analyzed. Results: Four hundred twenty three patients, between 16-82 years old (median: 52 were evaluated. Nearly half of the patients (185, 43% reported a better appetite at home than in hospital and declared that hospitalization is an important cause of loss of appetite (140/185, 75.6%. Presence of nausea/vomiting (N/V, depression, age less than 65 and use of non-steroidal anti-inflammatory drugs (NSAIDs were associated with increased risk of INS in hospitalized cancer patients. On the contrary, steroid medication showed a positive impact on nutritional status of cancer patients. Conclusion: N/V, younger age, presence of depression and NSAIDs medication were associated with INS in hospitalized cancer patients. Clinicians should pay more attention to this group of patients. In addition, unnecessary hospitalizations and medications that may disturb oral intake must be avoided. Corticosteroids are important tools for managing anorexia and INS.

  10. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable

  11. Isolated limb perfusion.

    Science.gov (United States)

    Gillespie, Rosalyn; Chantier, Nariane

    1994-12-08

    Growing concern over the rising incidence of malignant melanoma has brought about a need for information on this disorder and the treatment available. Isolated limb perfusion is a relatively new technique used in only a few hospitals. An increased knowledge base will lead to a better understanding of the nursing care required and to a more in-depth care plan.

  12. In-vivo quantitative evaluation of perfusion zones and perfusion gradient in the deep inferior epigastric artery perforator flap

    Science.gov (United States)

    Saint-Cyr, Michel; Lakhiani, Chrisovalantis; Cheng, Angela; Mangum, Michael; Liang, Jinyang; Teotia, Sumeet; Livingston, Edward H.; Zuzak, Karel J.

    2013-03-01

    The selection of well-vascularized tissue during DIEP flap harvest remains controversial. While several studies have elucidated cross-midline perfusion, further characterization of perfusion to the ipsilateral hemiabdomen is necessary for minimizing rates of fat necrosis or partial fat necrosis in bilateral DIEP flaps. Eighteen patients (29 flaps) underwent DIEP flap harvest using a prospectively designed protocol. Perforators were marked and imaged with a novel system for quantitatively measuring tissue oxygenation, the Digital Light Hyperspectral Imager. Images were then analyzed to determine if perforator selection influenced ipsilateral flap perfusion. Flaps based on a single lateral row perforator (SLRP) were found to have a higher level of hemoglobin oxygenation in Zone I (mean %HbO2 = 76.1) compared to single medial row perforator (SMRP) flaps (%HbO2 = 71.6). Perfusion of Zone III relative to Zone I was similar between SLRP and SMRP flaps (97.4% vs. 97.9%, respectively). These differences were not statistically significant (p>0.05). Perfusion to the lateral edge of the flap was slightly greater for SLRP flaps compared SMRP flaps (92.1% vs. 89.5%, respectively). SMRP flaps had superior perfusion travelling inferiorly compared to SLRP flaps (88.8% vs. 83.9%, respectively). Overall, it was observed that flaps were better perfused in the lateral direction than inferiorly. Significant differences in perfusion gradients directed inferiorly or laterally were observed, and perforator selection influenced perfusion in the most distal or inferior aspects of the flap. This suggests broader clinical implications for flap design that merit further investigation.

  13. A 4D digital phantom for patient-specific simulation of brain CT perfusion protocols.

    Science.gov (United States)

    van den Boom, Rieneke; Manniesing, Rashindra; Oei, Marcel T H; van der Woude, Willem-Jan; Smit, Ewoud J; Laue, Hendrik O A; van Ginneken, Bram; Prokop, Mathias

    2014-07-01

    Optimizing CT brain perfusion protocols is a challenge because of the complex interaction between image acquisition, calculation of perfusion data, and patient hemodynamics. Several digital phantoms have been developed to avoid unnecessary patient exposure or suboptimum choice of parameters. The authors expand this idea by using realistic noise patterns and measured tissue attenuation curves representing patient-specific hemodynamics. The purpose of this work is to validate that this approach can realistically simulate mean perfusion values and noise on perfusion data for individual patients. The proposed 4D digital phantom consists of three major components: (1) a definition of the spatial structure of various brain tissues within the phantom, (2) measured tissue attenuation curves, and (3) measured noise patterns. Tissue attenuation curves were measured in patient data using regions of interest in gray matter and white matter. By assigning the tissue attenuation curves to the corresponding tissue curves within the phantom, patient-specific CTP acquisitions were retrospectively simulated. Noise patterns were acquired by repeatedly scanning an anthropomorphic skull phantom at various exposure settings. The authors selected 20 consecutive patients that were scanned for suspected ischemic stroke and constructed patient-specific 4D digital phantoms using the individual patients' hemodynamics. The perfusion maps of the patient data were compared with the digital phantom data. Agreement between phantom- and patient-derived data was determined for mean perfusion values and for standard deviation in de perfusion data using intraclass correlation coefficients (ICCs) and a linear fit. ICCs ranged between 0.92 and 0.99 for mean perfusion values. ICCs for the standard deviation in perfusion maps were between 0.86 and 0.93. Linear fitting yielded slope values between 0.90 and 1.06. A patient-specific 4D digital phantom allows for realistic simulation of mean values and

  14. Fractal analysis in radiological and nuclear medicine perfusion imaging: a systematic review.

    Science.gov (United States)

    Michallek, Florian; Dewey, Marc

    2014-01-01

    To provide an overview of recent research in fractal analysis of tissue perfusion imaging, using standard radiological and nuclear medicine imaging techniques including computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) and to discuss implications for different fields of application. A systematic review of fractal analysis for tissue perfusion imaging was performed by searching the databases MEDLINE (via PubMed), EMBASE (via Ovid) and ISI Web of Science. Thirty-seven eligible studies were identified. Fractal analysis was performed on perfusion imaging of tumours, lung, myocardium, kidney, skeletal muscle and cerebral diseases. Clinically, different aspects of tumour perfusion and cerebral diseases were successfully evaluated including detection and classification. In physiological settings, it was shown that perfusion under different conditions and in various organs can be properly described using fractal analysis. Fractal analysis is a suitable method for quantifying heterogeneity from radiological and nuclear medicine perfusion images under a variety of conditions and in different organs. Further research is required to exploit physiologically proven fractal behaviour in the clinical setting. • Fractal analysis of perfusion images can be successfully performed. • Tumour, pulmonary, myocardial, renal, skeletal muscle and cerebral perfusion have already been examined. • Clinical applications of fractal analysis include tumour and brain perfusion assessment. • Fractal analysis is a suitable method for quantifying perfusion heterogeneity. • Fractal analysis requires further research concerning the development of clinical applications.

  15. Inadequate control of world's radioactive sources

    International Nuclear Information System (INIS)

    2002-01-01

    The radioactive materials needed to build a 'dirty bomb' can be found in almost any country in the world, and more than 100 countries may have inadequate control and monitoring programs necessary to prevent or even detect the theft of these materials. The IAEA points out that while radioactive sources number in the millions, only a small percentage have enough strength to cause serious radiological harm. It is these powerful sources that need to be focused on as a priority. In a significant recent development, the IAEA, working in collaboration with the United States Department of Energy (DOE) and the Russian Federation's Ministry for Atomic Energy (MINATOM), have established a tripartite working group on 'Securing and Managing Radioactive Sources'. Through its program to help countries improve their national infrastructures for radiation safety and security, the IAEA has found that more than 100 countries may have no minimum infrastructure in place to properly control radiation sources. However, many IAEA Member States - in Africa, Asia, Latin America, and Europe - are making progress through an IAEA project to strengthen their capabilities to control and regulate radioactive sources. The IAEA is also concerned about the over 50 countries that are not IAEA Member States (there are 134), as they do not benefit from IAEA assistance and are likely to have no regulatory infrastructure. The IAEA has been active in lending its expertise to search out and secure orphaned sources in several countries. More than 70 States have joined with the IAEA to collect and share information on trafficking incidents and other unauthorized movements of radioactive sources and other radioactive materials. The IAEA and its Member States are working hard to raise levels of radiation safety and security, especially focusing on countries known to have urgent needs. The IAEA has taken the leading role in the United Nations system in establishing standards of safety, the most significant of

  16. EFFECT ON PERFUSION VALUES OF SAMPLING INTERVAL OF CT PERFUSION ACQUISITIONS IN NEUROENDOCRINE LIVER METASTASES AND NORMAL LIVER

    Science.gov (United States)

    Ng, Chaan S.; Hobbs, Brian P.; Wei, Wei; Anderson, Ella F.; Herron, Delise H.; Yao, James C.; Chandler, Adam G.

    2014-01-01

    Objective To assess the effects of sampling interval (SI) of CT perfusion acquisitions on CT perfusion values in normal liver and liver metastases from neuroendocrine tumors. Methods CT perfusion in 16 patients with neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction, for tumor and normal liver. CT perfusion values for the reference sampling interval of 0.5s (SI0.5) were compared with those of SI datasets of 1s, 2s, 3s and 4s, using mixed-effects model analyses. Results Increases in SI beyond 1s were associated with significant and increasing departures of CT perfusion parameters from reference values at SI0.5 (p≤0.0009). CT perfusion values deviated from reference with increasing uncertainty with increasing SIs. Findings for normal liver were concordant. Conclusion Increasing SIs beyond 1s yield significantly different CT perfusion parameter values compared to reference values at SI0.5. PMID:25626401

  17. Human males and females body thermoregulation: perfusion effect analysis.

    Science.gov (United States)

    Acharya, Saraswati; Gurung, D B; Saxena, V P

    2014-10-01

    Skin temperature is a common physiological parameter that reflects thermal responses. Blood perfusion is an important part of the physiological processes that the human body undergoes in order to maintain homeostasis. This study focuses on the effect of perfusion on the temperature distribution in human males and females body in different thermal environment. The study has been carried out for one dimensional steady cases using finite element method. The input parameter of the model is the blood perfusion or volumetric flow rate within the tissue. The appropriate physical and physiological parameters together with suitable boundary conditions that affect the heat regulations have been incorporated in the model. The study is to have a better understanding that how does thermoregulation change in human males and females skin layered due to perfusion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Optical investigation of functional structures in isolated perfused pig heart

    Science.gov (United States)

    Rauh, Robert; Boehnert, Markus; Mahlke, Christine; Kessler, Manfred D.

    2000-11-01

    Light scattering in tissue of mammals and humans is affected by subcellular structures. Since these structures correlate well with the status of cells and tissue, light scattering seems to be ideal for monitoring of functional tissue state. By use of EMPHO SSK Oxyscan we investigated functional parameters in a novel kind of isolated perfused pig heart model. In this perfusion model we use organs obtained by the local slaughterhouse that are reanimated at our institute by application of a heart-lung machine. By creating 3D-images of tissue scattering we found an interesting relation between anatomical structures of myocardium and the 3D-images. Additionally, we detected coherence between backscattered light intensity and functional tissue status. Furthermore, we got a sight into the redox state of cytochrome aa3, b and c by creating difference spectra. We believe that this new kind of tissue imaging method will give us the opportunity to get new insights into myocardial function.

  19. Correlation of the myocardial perfusion corrected by attenuation with the coronariography. Preliminary results; Correlacion de la perfusion miocardica corregida por atenuacion con la coronariografia

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, S.E.; Garcia O, R. [Servicio de Medicina Nuclear, Centro Medico ABC, Campis Observatorio, IAP (Mexico)

    2005-07-01

    The attenuation that suffers the radiation in the soft tissues of the hinders the appropriate interpretation of the myocardial perfusion studies, for what have been implemented attenuation correction systems to reduce the attenuation for soft tissues and to provide myocardial perfusion images more accurate in the diagnosis of coronary illness. The objective was to evaluate the utility of an attenuation correction system (with source of Gadolinium 153) to minimize the devices that look like true defects of myocardial perfusion, caused by soft tissues (mammary tissue, thoracic wall, abdomen, left hemi diaphragm), and to compare those interpretations of the studies with the interpretations of the corresponding coronariographies. The method consists of 95 electronic files which were revised with the concept of heart catheterization, being identified 20 patients from the masculine sex to those that underwent coronariography among May 1999 and December 2002, and that they had study of myocardial perfusion in a maximum period of 3 months foresaw to the invasive procedure. (Author)

  20. A holistic approach for perfusion assessment in septic shock: Basic foundations and clinical applications

    NARCIS (Netherlands)

    Hernández Poblete, G.W.

    2013-01-01

    A fundamental challenge in septic shock resuscitation is to evaluate tissue perfusion. In this thesis, we review the basic foundations for the development of a comprehensive and holistic model for perfusion assessment in septic shock, and outline its application to evaluate the impact of

  1. Reverse ventilation--perfusion mismatch

    Energy Technology Data Exchange (ETDEWEB)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients.

  2. Erbium-Based Perfusion Contrast Agent for Small-Animal Microvessel Imaging

    Directory of Open Access Journals (Sweden)

    Justin J. Tse

    2017-01-01

    Full Text Available Micro-computed tomography (micro-CT facilitates the visualization and quantification of contrast-enhanced microvessels within intact tissue specimens, but conventional preclinical vascular contrast agents may be inadequate near dense tissue (such as bone. Typical lead-based contrast agents do not exhibit optimal X-ray absorption properties when used with X-ray tube potentials below 90 kilo-electron volts (keV. We have developed a high-atomic number lanthanide (erbium contrast agent, with a K-edge at 57.5 keV. This approach optimizes X-ray absorption in the output spectral band of conventional microfocal spot X-ray tubes. Erbium oxide nanoparticles (nominal diameter 4000 Hounsfield units, and perfusion of vessels < 10 μm in diameter was demonstrated in kidney glomeruli. The described new contrast agent facilitated the visualization and quantification of vessel density and microarchitecture, even adjacent to dense bone. Erbium’s K-edge makes this contrast agent ideally suited for both single- and dual-energy micro-CT, expanding potential preclinical research applications in models of musculoskeletal, oncological, cardiovascular, and neurovascular diseases.

  3. Perfusion Bioreactor Module

    Science.gov (United States)

    Morrison, Dennis R.

    1990-01-01

    Perfusion bioreactor module, self-contained, closed-loop cell-culture system that operates in microgravity or on Earth. Equipment supports growth or long-term maintenance of cultures of human or other fragile cells for experiments in basic cell biology or process technology. Designed to support proliferation (initially at exponential rates of growth) of cells in complex growth medium and to maintain confluent cells in defined medium under conditions optimized to permit or encourage selected functions of cells, including secretion of products of cells into medium.

  4. A Review of Liver Perfusion Method in Toxicology Studies

    Directory of Open Access Journals (Sweden)

    M karami

    2014-06-01

    Full Text Available Introduction: The isolated perfused rat liver is an accepted method in toxicology studies. The isolated perfused rat liver (IPRL is a useful experimental system for evaluating hepatic function without the influence of other organ systems, undefined plasma constituents, and neural-hormonal effects. Methods: The untreated male rats (180-220gr body weight were anesthetised with ether and then surgery with proper method. The abdomen was opened through a midline and one transversal incision and the bile duct was cannulated. Heparin sodium solution (0.5 ml; 500 U/ml in 0.9% NaCl was injected via the abdominal vena cava to prevent blood clotting. The liver inferior venacava was cannulated with PE-10 tubing and secured. The portal vein was immediately cannulated with an 23gr catheter which was secured and then liver was perfused in situ by Krebs- Henseleit buffer (pH 7.4; saturated with 95% O2 and 5% CO2; 37°C at a flow rate of 20 ml/min for 3hr. Temperature, perfusion pressure, flow rate and perfusion fluid pH were closely monitored during the perfusion. Results: Transferase enzymes (ALT, AST alterations can be widely used as a measure of biochemical alterations in order to assess liver damage due to use of drugs such as isoniazid (INH and animal and plant toxins. Accumulated material in gallbladder are valuable samples to assess the level of Glutathione (GSH. Sections of perfused liver tissue can also be effectively analyzed for pathological aspects such as necrosis, fibrosis, cellularity. Conclusion: The isolated perfused rat liver (IPRL is a useful and Sutible experimental system for evaluating hepatic function. In this system, the effects of adjacent organs, on the liver is minimized

  5. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...

  6. Laser Doppler perfusion monitoring and imaging: novel approaches

    NARCIS (Netherlands)

    Humeau, Anne; Steenbergen, Wiendelt; Nilsson, Henrik; Strömberg, Tomas

    2007-01-01

    Laser Doppler flowmetry (LDF) is a non invasive method enabling the monitoring of microvascular blood flow, a very important marker of tissue health. This article gives an overview on the concept of LDF for microvascular perfusion monitoring and imaging. It first describes the theoretical background

  7. Metabolic regulation during sport events: factual interpretations and inadequate allegations

    Directory of Open Access Journals (Sweden)

    Jacques Remy Poortmans

    2013-09-01

    Full Text Available Different fuels are available to generate ATP for muscle activities during sport events. Glycogen from striated muscles and liver stores may be converted to lactic acid or almost completely oxidized to carbon dioxide (CO2, triacylglycerol within the muscle itself and fatty acids from adipose tissue could be converted to CO2 in acting muscles, some free amino acids can be released within the muscle itself and from intestinal stores to sustain the amount of ATP generation indispensable for muscle contraction. All single biochemical reactions, but one, need one or several enzymes to activate the conversion of a substrate into a product. The energy transformation in biochemical reactions is led by application of so-called free energy. Reversible and non-reversible reactions within a metabolic pathway are dependent on specific enzymes near or far from equilibrium. Allosteric enzymes are regulatory enzymes that provide the direction in the pathway. A regulatory enzyme is either activated or inhibited by small regulators (ligands. A reversible substrate cycle between A and B is catalyzed by two enzymes with different fluxes. The need of ATP production for muscle contraction is under the leadership of regulatory enzymes and available substrate stores. The improvement of adapted metabolic reactions under sport training depends on the appropriate increase of regulatory enzymes within the glycolytic and oxidative pathways. The amount of some specific enzymes is increased by training in order to improve the maximum activity of the metabolic pathway. Unfortunately, several publications do not precisely implicate the appropriate enzyme(s to explain or reject the adaptation induced by the training schedule. A few examples will illustrate the factual interpretation and the inadequate allegation.

  8. Correlation of the myocardial perfusion corrected by attenuation with the coronariography. Preliminary results

    International Nuclear Information System (INIS)

    Garcia C, S.E.; Garcia O, R.

    2005-01-01

    The attenuation that suffers the radiation in the soft tissues of the hinders the appropriate interpretation of the myocardial perfusion studies, for what have been implemented attenuation correction systems to reduce the attenuation for soft tissues and to provide myocardial perfusion images more accurate in the diagnosis of coronary illness. The objective was to evaluate the utility of an attenuation correction system (with source of Gadolinium 153) to minimize the devices that look like true defects of myocardial perfusion, caused by soft tissues (mammary tissue, thoracic wall, abdomen, left hemi diaphragm), and to compare those interpretations of the studies with the interpretations of the corresponding coronariographies. The method consists of 95 electronic files which were revised with the concept of heart catheterization, being identified 20 patients from the masculine sex to those that underwent coronariography among May 1999 and December 2002, and that they had study of myocardial perfusion in a maximum period of 3 months foresaw to the invasive procedure. (Author)

  9. Ray-Based Approach to Skeletal Muscle Perfusion Measurement on Interventional X-ray Systems

    NARCIS (Netherlands)

    Giordano, M.; Vonken, E.J.; Bertram, M.; Mali, W.; Viergever, M.A.; Neukirchen, C.

    2012-01-01

    Purpose: Quantitative assessment of tissue perfusion by imaging methods could improve outcome control during treatment of peripheral vascular disease. Currently, revascularization treatments are assessedby planar angiography which only allows for qualitative inspection of blood flow in vessels. In

  10. Autologous mesenchymal stem cells produce concordant improvements in regional function, tissue perfusion, and fibrotic burden when administered to patients undergoing coronary artery bypass grafting: The Prospective Randomized Study of Mesenchymal Stem Cell Therapy in Patients Undergoing Cardiac Surgery (PROMETHEUS) trial.

    Science.gov (United States)

    Karantalis, Vasileios; DiFede, Darcy L; Gerstenblith, Gary; Pham, Si; Symes, James; Zambrano, Juan Pablo; Fishman, Joel; Pattany, Pradip; McNiece, Ian; Conte, John; Schulman, Steven; Wu, Katherine; Shah, Ashish; Breton, Elayne; Davis-Sproul, Janice; Schwarz, Richard; Feigenbaum, Gary; Mushtaq, Muzammil; Suncion, Viky Y; Lardo, Albert C; Borrello, Ivan; Mendizabal, Adam; Karas, Tomer Z; Byrnes, John; Lowery, Maureen; Heldman, Alan W; Hare, Joshua M

    2014-04-11

    Although accumulating data support the efficacy of intramyocardial cell-based therapy to improve left ventricular (LV) function in patients with chronic ischemic cardiomyopathy undergoing CABG, the underlying mechanism and impact of cell injection site remain controversial. Mesenchymal stem cells (MSCs) improve LV structure and function through several effects including reducing fibrosis, neoangiogenesis, and neomyogenesis. To test the hypothesis that the impact on cardiac structure and function after intramyocardial injections of autologous MSCs results from a concordance of prorecovery phenotypic effects. Six patients were injected with autologous MSCs into akinetic/hypokinetic myocardial territories not receiving bypass graft for clinical reasons. MRI was used to measure scar, perfusion, wall thickness, and contractility at baseline, at 3, 6, and 18 months and to compare structural and functional recovery in regions that received MSC injections alone, revascularization alone, or neither. A composite score of MRI variables was used to assess concordance of antifibrotic effects, perfusion, and contraction at different regions. After 18 months, subjects receiving MSCs exhibited increased LV ejection fraction (+9.4 ± 1.7%, P=0.0002) and decreased scar mass (-47.5 ± 8.1%; P<0.0001) compared with baseline. MSC-injected segments had concordant reduction in scar size, perfusion, and contractile improvement (concordant score: 2.93 ± 0.07), whereas revascularized (0.5 ± 0.21) and nontreated segments (-0.07 ± 0.34) demonstrated nonconcordant changes (P<0.0001 versus injected segments). Intramyocardial injection of autologous MSCs into akinetic yet nonrevascularized segments produces comprehensive regional functional restitution, which in turn drives improvement in global LV function. These findings, although inconclusive because of lack of placebo group, have important therapeutic and mechanistic hypothesis-generating implications. http

  11. The role of abutment-attachment selection in resolving inadequate interarch distance: a clinical report.

    Science.gov (United States)

    Alsiyabi, Abdullah S; Felton, David A; Cooper, Lyndon F

    2005-09-01

    A critical factor that needs to be evaluated during the diagnosis and treatment planning phase for patients seeking an implant-tissue-supported overdenture or metal-resin implant fixed denture is the presence of adequate interarch distance. The amount of interarch distance is critical to the selection of appropriate implant abutments and attachments for both implant-tissue-supported overdentures and metal-resin implant fixed complete dentures. This clinical report describes a patient with complications related to the failure to diagnose inadequate interarch distance, and the methods used to resolve the patient's chief complaint. A guide for abutment-attachment selection using one commercially available implant system is given.

  12. The Link Between Inadequate Sleep and Obesity in Young Adults.

    Science.gov (United States)

    Vargas, Perla A

    2016-03-01

    The prevalence of obesity has increased dramatically over the past decade. Although an imbalance between caloric intake and physical activity is considered a key factor responsible for the increase, there is emerging evidence suggesting that other factors may be important contributors to weight gain, including inadequate sleep. Overall research evidence suggests that inadequate sleep is associated with obesity. Importantly, the strength and trajectory of the association seem to be influenced by multiple factors including age. Although limited, the emerging evidence suggests young adults might be at the center of a "perfect health storm," exposing them to the highest risk for obesity and inadequate sleep. Unfortunately, the methods necessary for elucidating the complex relationship between sleep and obesity are lacking. Uncovering the underlying factors and trajectories between inadequate sleep and weight gain in different populations may help to identify the windows of susceptibility and to design targeted interventions to prevent the negative impact of obesity and related diseases.

  13. Non-Invasive Renal Perfusion Imaging Using Arterial Spin Labeling MRI: Challenges and Opportunities

    Directory of Open Access Journals (Sweden)

    Fabio Nery

    2018-01-01

    Full Text Available Tissue perfusion allows for delivery of oxygen and nutrients to tissues, and in the kidneys is also a key determinant of glomerular filtration. Quantification of regional renal perfusion provides a potential window into renal (patho physiology. However, non-invasive, practical, and robust methods to measure renal perfusion remain elusive, particularly in the clinic. Arterial spin labeling (ASL, a magnetic resonance imaging (MRI technique, is arguably the only available method with potential to meet all these needs. Recent developments suggest its viability for clinical application. This review addresses several of these developments and discusses remaining challenges with the emphasis on renal imaging in human subjects.

  14. Perfusion measurement in acute pancreatitis using dynamic perfusion MDCT.

    Science.gov (United States)

    Bize, Pierre E; Platon, Alexandra; Becker, Christoph D; Poletti, Pierre-Alexandre

    2006-01-01

    Our objective was to determine whether MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis in the initial phase of the disease. One hundred six patients with abdominal pain were prospectively enrolled in this study. Patients were separated into two groups: P1 (severe) and P2 (mild) acute pancreatitis. Mean perfusion value was 24.8 mL/100 mL/min in the P1 group and 50.5 mL/100 mL/min in the P2 group (p = 0.0016, significant). Our preliminary data suggest that pancreatic perfusion measurement using MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis.

  15. Perfusion defects in pulmonary perfusion iodine maps: causes and semiology.

    Science.gov (United States)

    Bustos Fiore, A; González Vázquez, M; Trinidad López, C; Mera Fernández, D; Costas Álvarez, M

    2017-12-14

    to describe the usefulness of dual-energy CT for obtaining pulmonary perfusion maps to provide morphological and functional information in patients with pulmonary embolisms. To review the semiology of perfusion defects due to pulmonary embolism so they can be differentiated from perfusion defects due to other causes: alterations outside the range used in the iodine map caused by other diseases of the lung parenchyma or artifacts. CT angiography of the pulmonary arteries is the technique of choice for the diagnosis of pulmonary embolisms. New dual-energy CT scanners are useful for detecting perfusion defects secondary to complete or partial obstruction of pulmonary arteries and is most useful for detecting pulmonary embolisms in subsegmental branches. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Whole ovine ovaries as a model for human: perfusion with cryoprotectants in vivo and in vitro.

    Science.gov (United States)

    Isachenko, Vladimir; Rahimi, Gohar; Dattena, Maria; Mallmann, Peter; Baikoshkarova, Saltanat; Kellerwessel, Elisabeth; Otarbaev, Marat; Shalakhmetova, Tamara; Isachenko, Evgenia

    2014-01-01

    These experiments were performed to test the perfusion of ovine as a model for human ovaries by cryoprotectants in vivo at high temperature when the permeability of capillaries is high and when blood is insensibly replaced by the solution of cryoprotectants. By our hypothetical supposition, ovaries could be saturated by cryoprotectants before their surgical removal. The objective was to examine the effectiveness of perfusion of ovine ovaries with vascular pedicle in vivo and in vitro. Arteria ovarica was cannuled and ovaries were perfused by Leibovitz L-15 medium + 100 IU/mL heparin + 5% bovine calf serum + 6% dimethyl sulfoxide + 6% ethylene glycol + 0.15 M sucrose + Indian ink in vivo and in vitro. In the first and second cycle of experiments, ovaries (n = 13 and n = 23) were perfused in vivo and in vitro, respectively, during 60 min with the rate of perfusion 50 mL/h (0.8 mL/min). It was established with in vivo perfusion that only about 10% of ovarian tissues were perfused due to an appearance of multiple anastomoses when the perfusion medium goes from arteria ovarica to arteria uterina without inflow into the ovaries. It was concluded that in vitro perfusion of ovine intact ovaries with vascular pedicle by freezing medium is more effective than this manipulation performed in vivo.

  17. The utility of first-pass perfusion CT in hyperacute ischemic stroke: early experience

    International Nuclear Information System (INIS)

    Lee, Tae Jin; Lee, Myeong Sub; Kim, Myung Soon; Hong, In Soo; Lee, Young Han; Lee, Ji Yong; Whang, Kum

    2003-01-01

    To evaluate the findings of first-pass perfusion CT in hyperacute stroke patients and to determine the relationship between a perfusion map and final infarct outcome. Thirty-five patients admitted with ischemic stroke within six hours of the onset of symptoms underwent conventional cerebral CT immediately followed by first-pass perfusion CT. Nineteen underwent follow-up CT or MRI, and three types of dynamic perfusion map-cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) - were evaluated by two radiologists. In these 19 patients, initial perfusion maps correlated with final infarct size, determined during follow-up studies. In all 35 patients, major large vessel perfusion abnormalities [middle cerebral artery - MCA MCA and anterior cerebral artery - ACA (n=2); posterior cerebral artery - PCA (n=8)] were detected. On first-pass perfusion maps depicting CBF and MTT, all lesions were detected, and CBF and delayed MTT values were recorded. CBV maps showed variable findings. In all 19 patients who were followed up, the final infarct size of perfusion abnormalities was less than that depicted on CBF and MTT maps, and similar to or much greater than that seen on CBV maps. First-pass perfusion CT scanning is a practical, rapid and advanced imaging technique. In hyperacute stroke patients, it provides important and reliable hemodynamic information as to which brain tissue is salvageable by thrombolytic therapy, and predicts outcome of such treatment

  18. Whole Ovine Ovaries as a Model for Human: Perfusion with Cryoprotectants In Vivo and In Vitro

    Directory of Open Access Journals (Sweden)

    Vladimir Isachenko

    2014-01-01

    Full Text Available These experiments were performed to test the perfusion of ovine as a model for human ovaries by cryoprotectants in vivo at high temperature when the permeability of capillaries is high and when blood is insensibly replaced by the solution of cryoprotectants. By our hypothetical supposition, ovaries could be saturated by cryoprotectants before their surgical removal. The objective was to examine the effectiveness of perfusion of ovine ovaries with vascular pedicle in vivo and in vitro. Arteria ovarica was cannuled and ovaries were perfused by Leibovitz L-15 medium + 100 IU/mL heparin + 5% bovine calf serum + 6% dimethyl sulfoxide + 6% ethylene glycol + 0.15 M sucrose + Indian ink in vivo and in vitro. In the first and second cycle of experiments, ovaries (n=13 and n=23 were perfused in vivo and in vitro, respectively, during 60 min with the rate of perfusion 50 mL/h (0.8 mL/min. It was established with in vivo perfusion that only about 10% of ovarian tissues were perfused due to an appearance of multiple anastomoses when the perfusion medium goes from arteria ovarica to arteria uterina without inflow into the ovaries. It was concluded that in vitro perfusion of ovine intact ovaries with vascular pedicle by freezing medium is more effective than this manipulation performed in vivo.

  19. Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

    Science.gov (United States)

    Kjørstad, Åsmund; Corteville, Dominique M R; Fischer, Andre; Henzler, Thomas; Schmid-Bindert, Gerald; Zöllner, Frank G; Schad, Lothar R

    2014-08-01

    To quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation- and perfusion-related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow-ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method. The standard FD perfusion images are quantified by comparing the partially blood-filled pixels in the lung parenchyma with the fully blood-filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced-MRI. All pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF-FD = 150 mL/min/100 mL, mean PBF-SEEPAGE = 151 mL/min/100 mL). The Bland-Altman plot shows a good spread of values, indicating no systematic bias between the methods. Quantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Copyright © 2013 Wiley Periodicals, Inc.

  20. Analysis of inadequate cervical smears using Shewhart control charts

    Directory of Open Access Journals (Sweden)

    Wall Michael K

    2004-06-01

    Full Text Available Abstract Background Inadequate cervical smears cannot be analysed, can cause distress to women, are a financial burden to the NHS and may lead to further unnecessary procedures being undertaken. Furthermore, the proportion of inadequate smears is known to vary widely amongst providers. This study investigates this variation using Shewhart's theory of variation and control charts, and suggests strategies for addressing this. Methods Cervical cytology data, from six laboratories, serving 100 general practices in a former UK Health Authority area were obtained for the years 2000 and 2001. Control charts of the proportion of inadequate smears were plotted for all general practices, for the six laboratories and for the practices stratified by laboratory. The relationship between proportion of inadequate smears and the proportion of negative, borderline, mild, moderate or severe dyskaryosis as well as the positive predictive value of a smear in each laboratory was also investigated. Results There was wide variation in the proportion of inadequate smears with 23% of practices showing evidence of special cause variation and four of the six laboratories showing evidence of special cause variation. There was no evidence of a clinically important association between high rates of inadequate smears and better detection of dyskaryosis (R2 = 0.082. Conclusions The proportion of inadequate smears is influenced by two distinct sources of variation – general practices and cytology laboratories, which are classified by the control chart methodology as either being consistent with common or special cause variation. This guidance from the control chart methodology appears to be useful in delivering the aim of continual improvement.

  1. Multi-detector CT perfusion

    Directory of Open Access Journals (Sweden)

    Ashraf M. Enite

    2016-09-01

    Conclusion: CTP is a promising non-invasive technique assessing the efficacy, predicting early response to local treatment therapies and monitoring tumor recurrence. It assesses the degree of post therapy tumor perfusion especially the degree of arterialization.

  2. A recapitulative three-dimensional model of breast carcinoma requires perfusion for multi-week growth

    Directory of Open Access Journals (Sweden)

    Kayla F Goliwas

    2016-07-01

    Full Text Available Breast carcinomas are complex, three-dimensional tissues composed of cancer epithelial cells and stromal components, including fibroblasts and extracellular matrix. In vitro models that more faithfully recapitulate this dimensionality and stromal microenvironment should more accurately elucidate the processes driving carcinogenesis, tumor progression, and therapeutic response. Herein, novel in vitro breast carcinoma surrogates, distinguished by a relevant dimensionality and stromal microenvironment, are described and characterized. A perfusion bioreactor system was used to deliver medium to surrogates containing engineered microchannels and the effects of perfusion, medium composition, and the method of cell incorporation and density of initial cell seeding on the growth and morphology of surrogates were assessed. Perfused surrogates demonstrated significantly greater cell density and proliferation and were more histologically recapitulative of human breast carcinoma than surrogates maintained without perfusion. Although other parameters of the surrogate system, such as medium composition and cell seeding density, affected cell growth, perfusion was the most influential parameter.

  3. Skin Blood Perfusion and Cellular Response to Insertion of Insulin Pen Needles With Different Diameters

    DEFF Research Database (Denmark)

    Præstmark, Kezia Ann; Stallknecht, Bente Merete; Bo Jensen, Casper

    2014-01-01

    skin blood perfusion response around needle insertion sites. Three common sized pen needles of 28G, 30G, and 32G as well as hooked 32G needles, were inserted into the neck skin of pigs and then removed. Laser Speckle Contrast Analysis was used to measure skin blood perfusion for 20 minutes after...... blood perfusion recording and grouped according to needle type, skin blood perfusion response relates to needle diameter. The response was significantly higher after insertions with 28G and hooked 32G needles than with 30G (P ..., but there was a trend of an increased response with increasing needle diameter. Skin blood perfusion response to pen needle insertions rank according to needle diameter, and the tissue response caused by hooked 32G needles corresponds to that of 28G needles. The relation between needle diameter and trauma when...

  4. Perfusion computed tomography to assist decision making for stroke thrombolysis.

    Science.gov (United States)

    Bivard, Andrew; Levi, Christopher; Krishnamurthy, Venkatesh; McElduff, Patrick; Miteff, Ferdi; Spratt, Neil J; Bateman, Grant; Donnan, Geoffrey; Davis, Stephen; Parsons, Mark

    2015-07-01

    The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative perfusion computed tomography classification: 253 treated patients and

  5. Transplacental pharmacokinetics of diclofenac in perfused human placenta.

    Science.gov (United States)

    Shintaku, Kyohei; Hori, Satoko; Tsujimoto, Masayuki; Nagata, Hideaki; Satoh, Shoji; Tsukimori, Kiyomi; Nakano, Hitoo; Fujii, Tomoyuki; Taketani, Yuji; Ohtani, Hisakazu; Sawada, Yasufumi

    2009-05-01

    The aims of this study were to evaluate the transplacental transfer properties of diclofenac and to determine the effect of L-lactic acid on the transplacental transfer of diclofenac. The maternal and fetal vessels of human placenta were perfused in a single-pass mode with a solution containing diclofenac and antipyrine. The transplacental pharmacokinetic model was fitted to the time profiles of the drug concentrations in the effluent and placenta to obtain transplacental pharmacokinetic parameters. In addition, chloride ion in the perfusate was partially replaced with L-lactic acid to see the change in the transplacental transfer properties of diclofenac. The TPT(ss) value (ratio of the rate of amount transferred across the placenta to that infused in the steady state) of diclofenac was 2.22%, which was approximately one-third that of antipyrine and was significantly reduced in the presence of L-lactic acid. The transplacental pharmacokinetic model could adequately explain the transplacental transfer of diclofenac with influx clearances from maternal and fetal perfusates to placental tissue of 0.276 and 0.0345 ml/min/g cotyledon and efflux rate constants from placental tissue to maternal and fetal perfusates of 0.406 and 0.0337 min(-1), respectively. By taking into account protein binding, the placental tissue/plasma concentration ratio in humans for diclofenac was estimated to be 0.108 ml/g of cotyledon and was smaller than that of antipyrine. In conclusion, human placental perfusion and transplacental pharmacokinetic modeling allowed us to determine the transplacental transfer properties of diclofenac quantitatively. Diclofenac may share transplacental transfer system(s) with L-lactic acid.

  6. The impact of inadequate wastewater treatment on the receiving ...

    African Journals Online (AJOL)

    The impact of inadequate wastewater treatment on the receiving water bodies – Case study: Buffalo City and Nkokonbe Municipalities of the Eastern Cape ... into their respective receiving water bodies (Tembisa Dam, the Nahoon and Eastern Beach which are part of the Indian Ocean; the Tyume River and the Kat River).

  7. The impact of inadequate wastewater treatment on the receiving ...

    African Journals Online (AJOL)

    7950 = Water SA (on-line). 687. The impact of inadequate wastewater treatment on the receiving water bodies – Case study: Buffalo City and. Nkokonbe Municipalities of the Eastern Cape Province. MNB Momba1*, AN Osode2 and M Sibewu1.

  8. Inadequate cerebral oxygen delivery and central fatigue during strenuous exercise

    DEFF Research Database (Denmark)

    Nybo, Lars; Rasmussen, Peter

    2007-01-01

    Under resting conditions, the brain is protected against hypoxia because cerebral blood flow increases when the arterial oxygen tension becomes low. However, during strenuous exercise, hyperventilation lowers the arterial carbon dioxide tension and blunts the increase in cerebral blood flow, which...... can lead to an inadequate oxygen delivery to the brain and contribute to the development of fatigue....

  9. Inadequate Information in Laboratory Test Requisition in a Tertiary ...

    African Journals Online (AJOL)

    Aim: Laboratory investigations are important aspect of patient management and inadequate information or errors arising from the process of filling out laboratory Request Forms can impact significantly on the quality of laboratory result and ultimately on patient care. Objectives: This study examined the pattern of deficiencies ...

  10. Inadequate sleep and muscle strength: Implications for resistance training.

    Science.gov (United States)

    Knowles, Olivia E; Drinkwater, Eric J; Urwin, Charles S; Lamon, Séverine; Aisbett, Brad

    2018-02-02

    Inadequate sleep (e.g., an insufficient duration of sleep per night) can reduce physical performance and has been linked to adverse metabolic health outcomes. Resistance exercise is an effective means to maintain and improve physical capacity and metabolic health, however, the outcomes for populations who may perform resistance exercise during periods of inadequate sleep are unknown. The primary aim of this systematic review was to evaluate the effect of sleep deprivation (i.e. no sleep) and sleep restriction (i.e. a reduced sleep duration) on resistance exercise performance. A secondary aim was to explore the effects on hormonal indicators or markers of muscle protein metabolism. A systematic search of five electronic databases was conducted with terms related to three combined concepts: inadequate sleep; resistance exercise; performance and physiological outcomes. Study quality and biases were assessed using the Effective Public Health Practice Project quality assessment tool. Seventeen studies met the inclusion criteria and were rated as 'moderate' or 'weak' for global quality. Sleep deprivation had little effect on muscle strength during resistance exercise. In contrast, consecutive nights of sleep restriction could reduce the force output of multi-joint, but not single-joint movements. Results were conflicting regarding hormonal responses to resistance training. Inadequate sleep impairs maximal muscle strength in compound movements when performed without specific interventions designed to increase motivation. Strategies to assist groups facing inadequate sleep to effectively perform resistance training may include supplementing their motivation by training in groups or ingesting caffeine; or training prior to prolonged periods of wakefulness. Copyright © 2018. Published by Elsevier Ltd.

  11. Estimating myocardial perfusion from dynamic contrast-enhanced CMR with a model-independent deconvolution method

    Directory of Open Access Journals (Sweden)

    Kadrmas Dan J

    2008-11-01

    Full Text Available Abstract Background Model-independent analysis with B-spline regularization has been used to quantify myocardial blood flow (perfusion in dynamic contrast-enhanced cardiovascular magnetic resonance (CMR studies. However, the model-independent approach has not been extensively evaluated to determine how the contrast-to-noise ratio between blood and tissue enhancement affects estimates of myocardial perfusion and the degree to which the regularization is dependent on the noise in the measured enhancement data. We investigated these questions with a model-independent analysis method that uses iterative minimization and a temporal smoothness regularizer. Perfusion estimates using this method were compared to results from dynamic 13N-ammonia PET. Results An iterative model-independent analysis method was developed and tested to estimate regional and pixelwise myocardial perfusion in five normal subjects imaged with a saturation recovery turboFLASH sequence at 3 T CMR. Estimates of myocardial perfusion using model-independent analysis are dependent on the choice of the regularization weight parameter, which increases nonlinearly to handle large decreases in the contrast-to-noise ratio of the measured tissue enhancement data. Quantitative perfusion estimates in five subjects imaged with 3 T CMR were 1.1 ± 0.8 ml/min/g at rest and 3.1 ± 1.7 ml/min/g at adenosine stress. The perfusion estimates correlated with dynamic 13N-ammonia PET (y = 0.90x + 0.24, r = 0.85 and were similar to results from other validated CMR studies. Conclusion This work shows that a model-independent analysis method that uses iterative minimization and temporal regularization can be used to quantify myocardial perfusion with dynamic contrast-enhanced perfusion CMR. Results from this method are robust to choices in the regularization weight parameter over relatively large ranges in the contrast-to-noise ratio of the tissue enhancement data.

  12. CT perfusion imaging in response assessment of pulmonary metastases undergoing stereotactic ablative radiotherapy.

    Science.gov (United States)

    Sawyer, Brooke; Pun, Emma; Samuel, Michael; Tay, Huilee; Kron, Tomas; Bressel, Mathias; Ball, David; Siva, Shankar

    2015-04-01

    Stereotactic ablative body radiotherapy (SABR) is an emerging treatment technique for pulmonary metastases in which conventional Response Evaluation Criteria in Solid Tumours (RECIST) may be inadequate. This study aims to assess the utility of CT perfusion imaging in response assessment of pulmonary metastases after SABR. In this ethics board-approved prospective study, 11 patients underwent a 26-Gy single fraction of SABR to pulmonary metastases. CT perfusion imaging occurred prior to and at 14 and 70 days post-SABR. Blood flow (mL/100 mL/min), blood volume (mL/100 mL), time to peak (seconds) and surface permeability (mL/100 mL/min), perfusion parameters of pulmonary metastases undergoing SABR, were independently assessed by two radiologists. Inter-observer variability was analysed. CT perfusion results were analysed for early response assessment comparing day 14 with baseline scans and for late response by comparing day 70 with baseline scans. The largest diameter of the pulmonary metastases undergoing SABR was recorded. Ten patients completed all three scans and one patient had baseline and early response assessment CT perfusion scans only. There was strong level of inter-observer agreement of CT perfusion interpretation with a median intraclass coefficient of 0.87 (range 0.20-0.98). Changes in all four perfusion parameters and tumour sizes were not statistically significant. CT perfusion imaging of pulmonary metastases is a highly reproducible imaging technique that may provide additional response assessment information above that of conventional RECIST, and it warrants further study in a larger cohort of patients undergoing SABR. © 2015 The Royal Australian and New Zealand College of Radiologists.

  13. CT perfusion imaging in response assessment of pulmonary metastases undergoing stereotactic ablative radiotherapy

    International Nuclear Information System (INIS)

    Sawyer, Brooke; Pun, Emma; Tay, Huilee; Kron, Tomas; Bressel, Mathias; Ball, David; Siva, Shankar; Samuel, Michael

    2015-01-01

    Stereotactic ablative body radiotherapy (SABR) is an emerging treatment technique for pulmonary metastases in which conventional Response Evaluation Criteria in Solid Tumours (RECIST) may be inadequate. This study aims to assess the utility of CT perfusion imaging in response assessment of pulmonary metastases after SABR. In this ethics board-approved prospective study, 11 patients underwent a 26-Gy single fraction of SABR to pulmonary metastases. CT perfusion imaging occurred prior to and at 14 and 70 days post-SABR. Blood flow (mL/100 mL/min), blood volume (mL/100 mL), time to peak (seconds) and surface permeability (mL/100 mL/min), perfusion parameters of pulmonary metastases undergoing SABR, were independently assessed by two radiologists. Inter-observer variability was analysed. CT perfusion results were analysed for early response assessment comparing day 14 with baseline scans and for late response by comparing day 70 with baseline scans. The largest diameter of the pulmonary metastases undergoing SABR was recorded. Ten patients completed all three scans and one patient had baseline and early response assessment CT perfusion scans only. There was strong level of inter-observer agreement of CT perfusion interpretation with a median intraclass coefficient of 0.87 (range 0.20–0.98). Changes in all four perfusion parameters and tumour sizes were not statistically significant. CT perfusion imaging of pulmonary metastases is a highly reproducible imaging technique that may provide additional response assessment information above that of conventional RECIST, and it warrants further study in a larger cohort of patients undergoing SABR.

  14. Lung perfusion scintigraphy by SPECT

    International Nuclear Information System (INIS)

    Hirayama, Takanobu

    1990-01-01

    The initial study reports the characteristic performance using lung segmental phantom filled in Tc-99m pertechnetate. To evaluate the segmental defect in lung perfusion scintigraphy, we applied Bull's-eye analysis in addition to planar image set. Bull's-eye analysis especially facilitated the interpretation in both middle and lower lobes. Subsequently, to evolute the clinical application of Bull's-eye analysis, pulmonary scintigraphy was performed on 10 normal subjects and 60 patients with several pulmonary diseases. Of interest, Bull's-eye analysis, however, encouraged the interpretation in both lower lobes. To calculate the extention and severity of perfusion defect, the present study describes Bull's-eye analysis. Quantitative scoring showed higher in patients with lung cancer than those with pulmonary tuberculosis. The present study focus that Bull's-eye analysis can be useful for evaluating perfusion in patients with a couple of pulmonary diseases. (author)

  15. Dynamic CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncological and Pathological Sciences, University of Rome “Sapienza”, Latina (Italy); Eid, Marwen [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Mangold, Stefanie [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen (Germany); and others

    2016-10-15

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  16. Dynamic CT myocardial perfusion imaging identifies early perfusion abnormalities in diabetes and hypertension : Insights from a multicenter registry

    NARCIS (Netherlands)

    Vliegenthart, Rozemarijn; De Cecco, Carlo N.; Wichmann, Julian L.; Meinel, Felix G.; Pelgrim, Gert Jan; Tesche, Christian; Ebersberger, Ullrich; Pugliese, Francesca; Bamberg, Fabian; Choe, Yeon Hyeon; Wang, Yining; Schoepf, U. Joseph

    2016-01-01

    Background: To identify patients with early signs of myocardial perfusion reduction, a reference base for perfusion measures is needed. Objective: To analyze perfusion parameters derived from dynamic computed tomography perfusion imaging (CTPI) in patients with suspected coronary artery disease

  17. Measurement of blood perfusion using photoacoustic, ultrasound, and strain imaging

    Science.gov (United States)

    Mallidi, Srivalleesha; Karpiouk, Andrei B.; Aglyamov, Salavat R.; Sethuraman, Shriram; Emelianov, Stanislav Y.

    2007-02-01

    In many clinical and research applications including cancer diagnosis, tumor response to therapy, reconstructive surgery, monitoring of transplanted tissues and organs, and quantitative evaluation of angiogenesis, sequential and quantitative assessment of microcirculation in tissue is required. In this paper we present an imaging technique capable of spatial and temporal measurements of blood perfusion through microcirculation. To demonstrate the developed imaging technique, studies were conducted using phantoms with modeled small blood vessels of various diameters positioned at different depths. A change in the magnitude of the photoacoustic signal was observed during vessel constriction and subsequent displacement of optically absorbing liquid present in the vessels. The results of the study suggest that photoacoustic, ultrasound and strain imaging could be used to sequentially monitor and qualitatively assess blood perfusion through microcirculation.

  18. Inadequate Empirical Antibiotic Therapy in Hospital Acquired Pneumonia.

    Science.gov (United States)

    Dahal, S; Rijal, B P; Yogi, K N; Sherchand, J B; Parajuli, K; Parajuli, N; Pokhrel, B M

    2015-01-01

    Inadequate empirical antibiotic therapy for HAP is a common phenomena and one of the indicators of the poor stewardship. This study intended to analyze the efficacy of empirical antibiotics in the light of microbiological data in HAP cases. Suspected cases of HAP were followed for clinico-bacterial evidence, antimicrobial resistance and pre and post culture antibiotic use. The study was taken from February,2014 to July 2014 in department of Microbiology and department of Respiratory medicine prospectively. Data was analyzed by Microsoft Office Excel 2007. Out of 758 cases investigated, 77(10 %) cases were HAP, 65(84%) of them were culture positive and 48(74 %) were late in onset. In early onset cases, isolates were Acinetobacter 10(42%), Escherichia coli 5(21%), S.aureus 4(17%), Klebsiella 1(4%) and Pseudomonas 1(4%). From the late onset cases Acinetobacter 15(28%), Klebsiella 17(32%) and Pseudomonas 13(24%) were isolated. All Acinetobacter, 78% Klebsiella and 36% Pseudomonas isolates were multi drug resistant. Empirical therapies were inadequate in 12(70%) of early onset cases and 44(92%) of late onset type. Cephalosporins were used in 7(41%) of early onset infections but found to be adequate only in 2(12%) cases. Polymyxins were avoided empirically but after cultures were used in 9(19%) cases. Empirical antibiotics were vastly inadequate, more frequently so in late onset infections. Use of cephalosporins empirically in early onset infections and avoiding empirical use of polymyxin antibiotics in late onset infections contributed largely to the findings. Inadequate empirical regimen is a real time feedback for a practitioner to update his knowledge on the local microbiological trends.

  19. Prona positioning in patients submitted to myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Cunha, C.J.; Ferreira, F.C.L.; Dullius, M.A.; Souza, S.O.; Souza, D.N.

    2011-01-01

    The myocardium perfusion scintigraphy corresponds at the nuclear medicine to one of best diagnostic methods for myocardium diseases. However, artefacts generated by the diaphragmatic tissue can induce to false positive diagnostic when does not occurs association of the image in supine position with the prone position. Images acquired at the two positions were analysed and the evaluation of tomographic images were estimation and consequently, a more completed diagnostic

  20. Distances walked in the six-minute walk test: suggestion of defining characteristic for the nursing diagnosis Ineffective Peripheral Tissue Perfusion Distancias recorridas en la prueba de caminata de los seis minutos: propuesta de característica definitoria para el diagnóstico de enfermería Perfusión Tisular Periférica Inefectiva Distâncias percorridas no teste de caminhada de seis minutos: proposta de característica definidora para o diagnóstico de enfermagem Perfusão Tissular Periférica Ineficaz

    Directory of Open Access Journals (Sweden)

    Rita de Cassia Gengo e Silva

    2012-04-01

    Full Text Available Distances walked in walking tests are important functional markers, although they are not accepted as defining characteristics of Ineffective Peripheral Tissue Perfusion. The aims of this study were to verify the distances participants with and without this nursing diagnosis walked in the six-minute walk test and if these measures may be considered defining characteristics of this phenomenon. Participants with (group A; n=65 and without (group B; n=17 this nursing diagnosis were evaluated regarding physical examination, vascular function and functional capacity. Participants of group A seemed to have worse vascular function and functional capacity compared with those of group B. Pain-free travelled distance was predictive of the nursing diagnosis. These results are important for the refinement of this diagnosis. In conclusion, this study provides evidences that the distances walked in the six-minute walk test may be considered defining characteristics of Ineffective Peripheral Tissue Perfusion.Las distancias en pruebas de marcha son importantes marcadores funcionales, pero no son aceptados como características de definición de la Perfusión Tisular Periférica Inefectiva. Los objetivos fueron determinar las distancias recorridas en la prueba de caminata de los seis minutos por los participantes con e sin el diagnóstico de enfermería y si esas medidas se pueden considerar características de definición de este fenómeno. Los participantes con (grupo A, n=65 y sin (grupo B, n=17 el diagnóstico fueron evaluados mediante examen físico, función vascular periférica y capacidad funcional. Los participantes del grupo A ha presentado peor función vascular y desempeño en la prueba de marcha do que aquellos del grupo B. La distancia recorrida libre de dolor fue predictiva del diagnóstico de enfermería. Los resultados de este estudio pueden contribuir para el refinamiento de este diagnóstico. Las distancias recorridas en la prueba de marcha se

  1. Automatic assessment of cardiac perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.

    2004-01-01

    In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...

  2. A new positive pressure ventilation delivery system: its impact on lung ventilation studies that are technically inadequate or non diagnostic

    International Nuclear Information System (INIS)

    Bui, C.; Leiper, C.; Lee, K.; Saunders, C.; Dixson, H.; Elison, B.; Bennett, G.; Gibian, T.; Rutland, J.; Tse, V.; Elzein, H.; Babicheva, R.

    2000-01-01

    Full text: The objective of this study was to evaluate the efficacy and safety of an improved Positive Pressure Ventilation Delivery System (PVDS) in the investigation of Pulmonary Embolism (PE). The major component of PVDS is a commercially available, self-inflating 1.6L Hudson Resuscitator Bag, filled with either oxygen or air (if the patient has CO 2 retention), which is squeezed by the operator to push Technegas from the Technegas Generator Chamber to the patient via the Patient Administration Set synchronously with patient inspiration. 27 spontaneously breathing in-patients (12 males, 15 females, age range 64-89, 21 with chronic airflow limitation), whose conventional lung ventilation images were technically inadequate or non diagnostic, were re-scanned using PVDS within four days after the conventional ventilation study. Randomised blinded visual interpretation of conventional ventilation/perfusion scan vs. PVDS-assisted ventilation/perfusion scan was performed by consensus reading with two experienced observers. In conclusion PVDS was safe and well tolerated. PVDS improved the image quality of the lung ventilation scans in this cohort of patients. This technique has the potential to improve the accuracy of lung scanning in patients with severe lung disease. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  3. [IV drug perfusions: safety principles].

    Science.gov (United States)

    Lelieur, Florence; Cabelguenne, Delphine; Marcel, Marie; Favier, Claudine; Piriou, Vincent

    2017-05-01

    An intravenous perfusion is a procedure which comprises infection and medication risks. To manage these risks, caregivers must respect, in addition to the usual hygiene rules, a series of best practices, ensuring the proper use and management of the medical devices and administered drugs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    ... to stop eating (fast), be on a special diet, or take any medicines before the test. A chest x-ray is usually done before or after a ventilation and perfusion scan. You wear a hospital gown or comfortable clothing that does not have ...

  5. Cardiovascular magnetic resonance: myocardial perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, E.; Al-Saadi, N.; Fleck, E. [Dept. of Internal Medicine/Cardiology, German Heart Inst. Berlin and Charite, Campus Virchow, Humboldt Univ. (Germany)

    2000-06-01

    There is growing evidence that the noninvasive assessment of myocardial perfusion with cardiovascular magnetic resonance is a valid and accurate tool for the assessment of ischemic heart disease and its introduction into routine clinical evaluation of patients is rapidly expected. Magnetic resonance measurements allow the evaluation of reversible and irreversible myocardial ischemia, the assessment of acute myocardial infarction, as well as the recognition and detection of viable myocardium. Magnetic resonance perfusion measurements are mainly performed with T1-shortening contrast agents such as gadolinium-DTPA either by visual analysis or based on the analyses of signal intensity time curves. For the detection of myocardial ischemia the first pass kinetics of a gadolinium-DTPA bolus and for the detection of myocardial necrosis and the definition of viable myocardium steady state distribution kinetics are assessed. Quantitative analysis of myocardial perfusion can be performed but requires complex modeling due to the characteristics of gadolinium-DTPA. Thus, semi-quantitative parameters are preferred. There is accumulating evidence in the literature that magnetic resonance imaging can be used for the detection of coronary artery stenosis with high diagnostic accuracy both with semi-quantitative or visual analysis. Myocardial infarction can be reliably detected and the infarcted area determined. Non-reperfused infarcted myocardium can be differentiated from reperfused myocardium by different enhancement patterns that correlates with viability. (orig.) [German] Die Magnetresonanztomographie (MR) erlangt bei der nichtinvasiven Diagnostik der koronaren Herzerkrankung eine zunehmende Bedeutung. Mit dieser Technik koennen sowohl die globale und regionale Myokardfunktion als auch die myokardiale Perfusion exakt beurteilt werden. Bisher liegen die meisten Daten fuer die Analyse von Wandbewegungsstoerun-gen unter Belastung vor, wobei sich eine deutliche diagnostische

  6. Perfusion CT assessment of the colon and rectum: Feasibility of quantification of bowel wall perfusion and vascularization

    International Nuclear Information System (INIS)

    Khan, Sairah; Goh, Vicky; Tam, Emily; Wellsted, David; Halligan, Steve

    2012-01-01

    The aim was to determine the feasibility of vascular quantification of the bowel wall for different anatomical segments of the colorectum. Following institutional ethical approval and informed consent, 39 patients with colorectal cancer underwent perfusion CT. Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface area product (PS) were assessed for different segments of the colorectum: ascending, transverse, descending colon, sigmoid, or rectum, that were distant from the tumor, and which were proven normal on contemporary colonoscopy, and subsequent imaging and clinical follow up. Mean (SD) for BF, BV, MTT and PS for the different anatomical colorectal segments were obtained and compared using a pooled t-test. Significance was at 5%. Assessment was not possible in 9 of 39 (23%) patients as the bowel wall was ≤5 mm precluding quantitative analysis. Forty-four segments were evaluated in the remaining 30 patients. Mean BF was higher in the proximal than distal colon: 24.0 versus 17.8 mL/min/100 g tissue; p = 0.009; BV, MTT and PS were not significantly different; BV: 3.46 versus 3.15 mL/100 g tissue, p = 0.45; MTT: 15.1 versus 18.3 s; p = 0.10; PS: 6.84 versus 8.97 mL/min/100 tissue, p = 0.13, respectively. In conclusion, assessment of bowel wall perfusion may fail in 23% of patients. The colorectum demonstrates segmental differences in perfusion.

  7. Steady-state first-pass perfusion (SSFPP): a new approach to 3D first-pass myocardial perfusion imaging.

    Science.gov (United States)

    Giri, Shivraman; Xue, Hui; Maiseyeu, Andrei; Kroeker, Randall; Rajagopalan, Sanjay; White, Richard D; Zuehlsdorff, Sven; Raman, Subha V; Simonetti, Orlando P

    2014-01-01

    To describe and characterize a new approach to first-pass myocardial perfusion utilizing balanced steady-state free precession acquisition without the use of saturation recovery or other magnetization preparation. The balanced steady-state free precession sequence is inherently sensitive to contrast agent enhancement of the myocardium. This sensitivity can be used to advantage in first-pass myocardial perfusion imaging by eliminating the need for magnetization preparation. Bloch equation simulations, phantom experiments, and in vivo 2D imaging studies were run comparing the proposed technique with three other methods: saturation recovery spoiled gradient echo, saturation recovery steady-state free precession, and steady-state spoiled gradient echo without magnetization preparation. Additionally, an acquisition-reconstruction strategy for 3D perfusion imaging is proposed and initial experience with this approach is demonstrated in healthy subjects and one patient. Phantom experiments verified simulation results showing the sensitivity of the balanced steady-state free precession sequence to contrast agent enhancement in solid tissue is similar to that of magnetization-prepared acquisitions. Images acquired in normal volunteers showed the proposed technique provided superior signal and signal-to-noise ratio compared with all other sequences at baseline as well as postcontrast. A new approach to first-pass myocardial perfusion is presented that obviates the need for magnetization preparation and provides high signal-to-noise ratio. Copyright © 2013 Wiley Periodicals, Inc.

  8. Contralateral thalamic hypoperfusion on brain perfusion SPECT

    International Nuclear Information System (INIS)

    Lee, Seok Mo; Bae, Sang Kyun; Yoo, Kyung Moo; Yum, Ha Yong

    2000-01-01

    Brain perfusion single photon emission computed tomography (SPECT) is useful for the localization of cerebrovascular lesion and sometimes reveals more definite lesion than radiologic imaging modality such as CT or MRI does. The purpose of this study was to evaluate the diagnostic usefulness of brain perfusion SPECT in patients with hemisensory impairment. Thirteen consecutive patients (M:F= 8:5, mean age = 48) who has hemisensory impairment were included. Brain perfusion SPECT was performed after intravenous injection of 1110 MBq of Tc-99m ECD. The images were obtained using a dual-head gamma camera with ultra-high resolution collimator. Semiquantitative analysis was performed after placing multiple ROIs on cerebral cortex, basal ganglia, thalamus and cerebellum. There were 10 patients with left hemisensory impairment and 3 patients with right-sided symptom. Only 2 patients revealed abnormal signal change in the thalamus on MRI. But brain perfusion SPECT showed decreased perfusion in the thalamus in 9 patients. Six patients among 10 patients with left hemisensory impairment revealed decreased perfusion in the contralateral thalamus on brain SPECT. The other 4 patients revealed no abnormality. Two patients among 3 patients with right hemisensory impairment also showed decreased perfusion in the contralateral thalamus on brain SPECT. One patients with right hemisensory impairment showed ipsilateral perfusion decrease. Two patients who had follow-up brain perfusion SEPCT after treatment revealed normalization of perfusion in the thalamus. Brain perfusion SPECT might be a useful tool in diagnosing patients with hemisensory impairment

  9. In vivo perfusion assessment of an anastomosis surgery on porcine intestinal model (Conference Presentation)

    Science.gov (United States)

    Le, Hanh N. D.; Opferman, Justin; Decker, Ryan; Cheon, Gyeong W.; Kim, Peter C. W.; Kang, Jin U.; Krieger, Axel

    2016-04-01

    Anastomosis, the connection of two structures, is a critical procedure for reconstructive surgery with over 1 million cases/year for visceral indication alone. However, complication rates such as strictures and leakage affect up to 19% of cases for colorectal anastomoses and up to 30% for visceral transplantation anastomoses. Local ischemia plays a critical role in anastomotic complications, making blood perfusion an important indicator for tissue health and predictor for healing following anastomosis. In this work, we apply a real time multispectral imaging technique to monitor impact on tissue perfusion due to varying interrupted suture spacing and suture tensions. Multispectral tissue images at 470, 540, 560, 580, 670 and 760 nm are analyzed in conjunction with an empirical model based on diffuse reflectance process to quantify the hemoglobin oxygen saturation within the suture site. The investigated tissues for anastomoses include porcine small (jejunum and ileum) and large (transverse colon) intestines. Two experiments using interrupted suturing with suture spacing of 1, 2, and 3 mm and tension levels from 0 N to 2.5 N are conducted. Tissue perfusion at 5, 10, 20 and 30 min after suturing are recorded and compared with the initial normal state. The result indicates the contrast between healthy and ischemic tissue areas and assists the determination of suturing spacing and tension. Therefore, the assessment of tissue perfusion will permit the development and intra-surgical monitoring of an optimal suture protocol during anastomosis with less complications and improved functional outcome.

  10. Monitoring Disease Activity in Patients with Aortitis and Chronic Periaortitis Undergoing Immunosuppressive Therapy by Perfusion CT.

    Science.gov (United States)

    Bier, Georg; Kurucay, Mustafa; Henes, Jörg; Xenitidis, Theodoros; Preibsch, Heike; Nikolaou, Konstantin; Horger, Marius

    2017-04-01

    To evaluate the role of perfusion CT for monitoring inflammatory activity in patients with aortitis and chronic periaortitis undergoing immunosuppressive therapy. Seventeen symptomatic patients (median age 68.5 years) who underwent perfusion-based computed tomography (CT) monitoring after diagnostic contrast-enhanced CT were retrospectively included in this study. Blood flow (BF), blood volume (BV), volume transfer constant (k-trans), time to peak, and mean transit time were determined by setting circular regions of interest in prominently thickened parts of the vessel wall or perfused surrounding tissue at sites where the perfusion CT color maps showed a maximum BF value. Differences in CT perfusion and, morphological parameters, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were tested for significance during therapy. In all patients BF and BV dropped at second perfusion CT (P perfusion CT parameters in aortitis and chronic periaortitis undergoing immunosuppressive therapy dropped at different extent after therapy. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  11. Development of an Ex-Situ Limb Perfusion System for a Rodent Model.

    Science.gov (United States)

    Gok, Emre; Alghanem, Fares; Moon, Ruth; Guy, Erin; Rojas-Pena, Alvaro; Bartlett, Robert H; Ozer, Kagan

    2018-03-26

    Ex-situ perfusion (ESP) is a promising method in preserving vascularized composite tissue allografts (VCAs) with potential to widen donor procurement to larger geographic areas. To optimize the method of preservation, we developed a small animal model to conduct biomolecular investigations. Twenty rat hind limbs (18.2 ± 1.3 g) were procured and connected to our custom-made ESP system. Perfusion pressure and flow parameters were measured with hourly blood gas analysis under near-normothermic (30-35˚C) conditions. Perfusate was prepared with swine hemoglobin (6-9 g/dL) and STEEN Solution. After 6 hours of perfusion, gastrocnemius muscles were evaluated for their histology and metabolomic profiling. Following 3 sets of experiments, perfusion was maintained at an average flow of 0.9 ± 0.24 mL/min and resulted in lactate levels of 3.78 ± 1.02 mmol/L. Metabolomic analysis revealed maintained cellular energy stores (total adenylates perfusion 0.698 ± 0.052 versus baseline 0.685 ± 0.091 umols/ug, p = 0.831), and histologic analysis revealed no evidence of barotrauma or myodegeneration. Rat hind limbs were viable after 6 hours of ESP on our miniaturized ESP system. This study is the first to document the ex-situ hind limb perfusion platform on a rodent model. These experimental findings have potential to guide future research to extend the viable duration of VCA preservation.

  12. Drug effects on functional structures in isolated perfused pig heart

    Science.gov (United States)

    Trinks, Tobias; Rauh, Robert; Hiller, Michael; Kessler, Manfred D.

    2002-06-01

    Until today monitoring of immediate drug tissue interaction in living organs is an unsolved problem. However, for the development of new drugs and the improvement of medical therapy outcome it would be helpful to get new tools to visualize drug effects on tissue directly. With the EMPHO II SSK and a 3D-scanning device we detected changes of functional structures in an isolated perfused pig heart model after adding commonly used drugs like verapamil, nitroglycerin and salviae miltiorrhizae (Chinese herbal drug). In the paper the results are presented.

  13. Dual-Energy Perfusion-CT in Recurrent Pancreatic Cancer - Preliminary Results.

    Science.gov (United States)

    Fritz, F; Skornitzke, S; Hackert, T; Kauczor, H U; Stiller, W; Grenacher, L; Klauss, M

    2016-06-01

    To evaluate the diagnostic performance of dual energy (DE) perfusion-CT for the differentiation between postoperative soft-tissue formation and tumor recurrence in patients after potentially curative pancreatic cancer resection. 24 patients with postoperative soft-tissue formation in the conventional regular follow-up CT acquisition after pancreatic cancer resection with curative intent were included prospectively. They were examined with a 64-row dual-source CT using a dynamic sequence of 34 DE acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). Weighted average (linearly blended M0.5) 120kVp-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (see above) for estimating blood flow, permeability, and blood volume. Diagnosis was confirmed by histological study (n = 4) and by regular follow-up. Final diagnosis was local recurrence of pancreatic cancer in 15 patients and unspecific postoperative tissue formation in 9 patients. The blood-flow values for recurrence tissue trended to be lower compared to postoperative tissue formation with 16.6 ml/100 ml/min and 24.7 ml/100 ml/min, respectively for weighted average 120kVp-equivalent image data, which was not significant (n.s.) (p = 0.06, significance level 0.05). Permeability- and blood-volume values were only slightly lower in recurrence tissue (n.s.). DE perfusion-CT is feasible in patients after pancreatic cancer resection and a promising functional imaging technique. As only a trend for lower perfusion values in local recurrence compared to unspecific postoperative alterations was found, the perfusion differences are not yet sufficient to differentiate between malignancy and unspecific postoperative alterations for this new technique. Further studies and technical improvements are needed to generate reliable data for this clinically highly relevant differentiation. • DE Perfusion CT is feasible in patients

  14. Bioprinting of 3D Convoluted Renal Proximal Tubules on Perfusable Chips

    Science.gov (United States)

    Homan, Kimberly A.; Kolesky, David B.; Skylar-Scott, Mark A.; Herrmann, Jessica; Obuobi, Humphrey; Moisan, Annie; Lewis, Jennifer A.

    2016-10-01

    Three-dimensional models of kidney tissue that recapitulate human responses are needed for drug screening, disease modeling, and, ultimately, kidney organ engineering. Here, we report a bioprinting method for creating 3D human renal proximal tubules in vitro that are fully embedded within an extracellular matrix and housed in perfusable tissue chips, allowing them to be maintained for greater than two months. Their convoluted tubular architecture is circumscribed by proximal tubule epithelial cells and actively perfused through the open lumen. These engineered 3D proximal tubules on chip exhibit significantly enhanced epithelial morphology and functional properties relative to the same cells grown on 2D controls with or without perfusion. Upon introducing the nephrotoxin, Cyclosporine A, the epithelial barrier is disrupted in a dose-dependent manner. Our bioprinting method provides a new route for programmably fabricating advanced human kidney tissue models on demand.

  15. Hemodynamic effects of decompressive craniotomy in MCA infarction: evaluation with perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Bendszus, Martin; Weigand, Alexandra; Solymosi, Laszlo [Department of Neuroradiolgoy, University of Wuerzburg, Josef-Schneider-Strasse 11, 97080 Wuerzburg (Germany); Muellges, Wolfgang [Department of Neurology, University of Wuerzburg, Josef-Schneider-Strasse 11, 97080 Wuerzburg (Germany); Goldbrunner, Roland [Department of Neurosurgery, University of Wuerzburg, Josef-Schneider-Strasse 11, 97080 Wuerzburg (Germany)

    2003-08-01

    Decompressive craniotomy in hemispheric infarction has been reported to reduce mortality and improve outcome. Identifying tissue at risk and monitoring the benefit of craniotomy is hardly practical and has not been reported thus far. Perfusion CT was applied before and immediately after decompressive craniotomy in a patient with space-occupying middle cerebral artery (MCA) infarction. Before surgery, perfusion CT revealed malperfused but still vital tissue in the vicinity of the infarction core which returned to normal after decompressive surgery. The final infarct size did not exceed the area of the initial hypodensity on unenhanced CT scan. In critically ill patients, the practicability of perfusion CT allows for demonstration of tissue at risk around the infarct core in space-occupying MCA infarction. Moreover, it may be used to monitor the effect of decompressive craniotomy. (orig.)

  16. Ventilation-perfusion matching during exercise

    Science.gov (United States)

    Wagner, P. D.

    1992-01-01

    In normal subjects, exercise widens the alveolar-arterial PO2 difference (P[A-a]O2) despite a more uniform topographic distribution of ventilation-perfusion (VA/Q) ratios. While part of the increase in P(A-a)O2 (especially during heavy exercise) is due to diffusion limitation, a considerable amount is caused by an increase in VA/Q mismatch as detected by the multiple inert gas elimination technique. Why this occurs is unknown, but circumstantial evidence suggests it may be related to interstitial pulmonary edema rather than to factors dependent on ventilation, airway gas mixing, airway muscle tone, or pulmonary vascular tone. In patients with lung disease, the gas exchange consequences of exercise are variable. Thus, arterial PO2 may increase, remain the same, or fall. In general, patients with advanced chronic obstructive pulmonary disease (COPD) or interstitial fibrosis who exercise show a fall in PO2. This is usually not due to worsening VA/Q relationships but mostly to the well-known fall in mixed venous PO2, which itself results from a relatively smaller increase in cardiac output than VO2. However, in interstitial fibrosis (but not COPD), there is good evidence that a part of the fall in PO2 on exercise is caused by alveolar-capillary diffusion limitation of O2 transport; in COPD (but not interstitial fibrosis), a frequent additional contributing factor to the hypoxemia of exercise is an inadequate ventilatory response, such that minute ventilation does not rise as much as does CO2 production or O2 uptake, causing arterial PCO2 to increase and PO2 to fall.

  17. Viability of the vascularly perfused, recirculating rat intestine and intestine-liver preparations

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, H.; Xu, X.; Pang, K.S. (Univ. of Toronto, Ontario (Canada))

    1989-08-01

    Function and stability of vascularly perfused, recirculating in situ rat intestine (I) and intestine-liver (IL) preparations were evaluated in fasted and nonfasted rats because these techniques may be readily applied in drug metabolism studies. The rat intestine was perfused with blood medium (7.5 ml/min) via the superior mesenteric artery, with the venous outflow draining into the portal vein, which, together with hepatic arterial flow (2.5 ml/min), constituted the total blood flow (10 ml/min) to the liver. Maintenance of intestinal membrane integrity was observed. Rapid ({sup 14}C)glucose absorption against a concentration gradient and a lack of ({sup 3}H)-polyethylene glycol 4000 (PEG 4000, less than 4%) and Evans blue absorption by the recirculating I and IL preparations resulted after bolus injections of these markers into the pyloric end of the duodenum. Other indexes that revealed stable intestinal and liver functions were the following: preservation of reservoir perfusate volume, constancy in perfusion pressure, bile flow, and hemoglobin concentrations, evidence of intestinal glucose utilization and liver glucose production, and a lack of significant leakage of serum glutamic oxalic transaminase. The intestine and liver consumed oxygen at relatively constant rates, but the consumption rates for the fasted tissues (I or L) were significantly higher than those for nonfasted tissues. These results indicate that the vascularly perfused I and IL preparations were maintained in a viable and stable state for a 2-h perfusion period.

  18. Deferasirox pharmacokinetics in patients with adequate versus inadequate response

    Science.gov (United States)

    Chirnomas, Deborah; Smith, Amber Lynn; Braunstein, Jennifer; Finkelstein, Yaron; Pereira, Luis; Bergmann, Anke K.; Grant, Frederick D.; Paley, Carole; Shannon, Michael

    2009-01-01

    Tens of thousands of transfusion-dependent (eg, thalassemia) patients worldwide suffer from chronic iron overload and its potentially fatal complications. The oral iron chelator deferasirox has become commercially available in many countries since 2006. Although this alternative to parenteral deferoxamine has been a major advance for patients with transfusional hemosiderosis, a proportion of patients have suboptimal response to the maximum approved doses (30 mg/kg per day), and do not achieve negative iron balance. We performed a prospective study of oral deferasirox pharmacokinetics (PK), comparing 10 transfused patients with inadequate deferasirox response (rising ferritin trend or rising liver iron on deferasirox doses > 30 mg/kg per day) with control transfusion-dependent patients (n = 5) with adequate response. Subjects were admitted for 4 assessments: deferoxamine infusion and urinary iron measurement to assess readily chelatable iron; quantitative hepatobiliary scintigraphy to assess hepatic uptake and excretion of chelate; a 24-hour deferasirox PK study following a single 35-mg/kg dose of oral deferasirox; and pharmacogenomic analysis. Patients with inadequate response to deferasirox had significantly lower systemic drug exposure compared with control patients (P deferasirox must be determined. This trial has been registered at http://www.clinicaltrials.gov under identifier NCT00749515. PMID:19724055

  19. Dual-energy perfusion-CT in recurrent pancreatic cancer. Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, F.; Skornitzke, S.; Kauczor, H.U.; Stiller, W.; Klauss, M. [Heidelberg Univ. (Germany). Clinic of Diagnostic and Interventional Radiology; Hackert, T. [Heidelberg Univ. (Germany). Clinic of Surgery; Grenacher, L. [Diagnostik Muenchen (Germany). Diagnostic Imaging Center

    2016-06-15

    To evaluate the diagnostic performance of dual energy (DE) perfusion-CT for the differentiation between postoperative soft-tissue formation and tumor recurrence in patients after potentially curative pancreatic cancer resection. 24 patients with postoperative soft-tissue formation in the conventional regular follow-up CT acquisition after pancreatic cancer resection with curative intent were included prospectively. They were examined with a 64-row dual-source CT using a dynamic sequence of 34 DE acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). Weighted average (linearly blended M0.5) 120 kVp-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool for estimating blood flow, permeability, and blood volume. Diagnosis was confirmed by histological study (n=4) and by regular follow-up. Final diagnosis was local recurrence of pancreatic cancer in 15 patients and unspecific postoperative tissue formation in 9 patients. The blood-flow values for recurrence tissue trended to be lower compared to postoperative tissue formation with 16.6 ml/100 ml/min and 24.7 ml/100 ml/min, respectively for weighted average 120 kVp-equivalent image data, which was not significant (n.s.) (p=0.06, significance level 0.05). Permeability- and blood-volume values were only slightly lower in recurrence tissue (n.s.). DE perfusion-CT is feasible in patients after pancreatic cancer resection and a promising functional imaging technique. As only a trend for lower perfusion values in local recurrence compared to unspecific postoperative alterations was found, the perfusion differences are not yet sufficient to differentiate between malignancy and unspecific postoperative alterations for this new technique. Further studies and technical improvements are needed to generate reliable data for this clinically highly relevant differentiation.

  20. Spatial relationship between tumor perfusion and endogeneous glucose distribution

    International Nuclear Information System (INIS)

    Schroeder, T.; Larrier, N.; Viglianti, B.; Rabbani, Z.N.; Peltz, C.; Vujascovic, Z.; Dewhirst, M.W.

    2003-01-01

    Earlier studies detecting glucose in tissue and solid tumors by bioluminescence imaging suggested, that glucose distribution patterns may be spatially related to functional vascularity. The purpose of this study was to evaluate this relationship by comparing glucose distribution patterns as determined by bioluminescence imaging to perfusion patterns of endogeneous Hoechst 33342 in rats bearing mammary carcinomas. R 3230 mammary carcinoma cells have been implanted subcutaneously into 7 female Fischer 344 rats. Two months post implantation, after injection of Hoechst 33342 the tumors were removed and snap frozen to conserve metabolite levels. Concomitantly, blood was sampled from the animals for analysis of glucose concentrations using a micodialysis analyzer. Cryosections of the tumors have been prepared, and every slice has been analyzed for both, Hoechst binding by fluorescence microscopy, and for glucose distribution patterns using bioluminescence imaging. In many cases vascular structures could be retrieved by the spatial pattern of glucose distribution. In some cases however, higher glucose concentrations could be found independent from Hoechst signal. On the other hand, regions of high Hoechst signal are not necessarily correlated with high glucose concentrations. When comparing blood and tissue glucose levels, tissue glucose content as measured with bioluminescence imaging (1.9-3.5 mM) is considerably lower than blood glucose (5.6-8.0 mM), demonstrating the expected gradient from blood to tissue. This study demonstrates the feasibility of monitoring glucose gradients in relation to functional vasculature throughout the body, from blood down to tissue or tumor and further, throughout the microenvironment of the solid tumor. Glucose distribution patterns may be an important tool in perfusion studies, e. g. in detecting the direction of blood flow in ex-vivo samples or in estimating glucose consumption rates of tumor cells adjacent to or in between perfused

  1. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...... in the anterior myocardial wall were (mean +/- SD) Ki = 54 +/- 10 ml/100 g/min, lambda = 30 +/- 3 ml/100 g, Vb = 9 +/- 2 ml/100 g, delta T = 3.2 +/- 1.1 s. These results are in good agreement with similar results obtained by other methods....

  2. Ventilation and ventilation/perfusion ratios

    International Nuclear Information System (INIS)

    Valind, S.O.

    1989-01-01

    The thesis is based on five different papers. The labelling of specific tracer compounds with positron emitting radionuclides enables a range of structural, physiological and biochemical parameters in the lung to be measured non-invasively, using positron emission tomography. This concept affords a unique opportunity for in vivo studies of different expressions of pulmonary pathophysiology at the regional level. The present thesis describes the application of positron emission tomography to the measurements of ventilation and ventilation/perfusion ratios using inert gas tracers, neon-19 and nitrogen-13 respectively. The validity of the methods applied was investigated with respect to the transport of inert gas tracers in the human lung. Both ventilation and the ventilation/perfusion ratio may be obtained with errors less than 10 % in the normal lung. In disease, however, errors may increase in those instances where the regional ventilation is very low or the intra-regional gas flow distribution is markedly nonuniform. A 2-3 fold increase in ventilation was demonstrated in normal nonsmoking subjects going from ventral to dorsal regions in the supine posture. These large regional differences could be well explained by the intrinsic elastic properties of lung tissue, considering the gravitational gradient in transpulmonary pressure. In asymptomatic smokers substantial regional ventilatroy abnormalities were found whilst the regional gas volume was similar in smokers and nonsmokers. The uncoupling between ventilation and gas volume probably reflects inflammatory changes in the airways. The regional differences in dV/dt/dQ/dt were relatively small and blood flow was largely matched to ventilation in the supine posture. However, small regions of lung with very low ventilation, unmatched by blood flow commonly exists in the most dependent parts of the lung in both smokers and nonsmokers. (29 illustrations, 7 tables, 113 references)

  3. Perfusion measurements by micro-CT using prior image constrained compressed sensing (PICCS): initial phantom results.

    Science.gov (United States)

    Nett, Brian E; Brauweiler, Robert; Kalender, Willi; Rowley, Howard; Chen, Guang-Hong

    2010-04-21

    Micro-CT scanning has become an accepted standard for anatomical imaging in small animal disease and genome mutation models. Concurrently, perfusion imaging via tracking contrast dynamics after injection of an iodinated contrast agent is a well-established tool for clinical CT scanners. However, perfusion imaging is not yet commercially available on the micro-CT platform due to limitations in both radiation dose and temporal resolution. Recent hardware developments in micro-CT scanners enable continuous imaging of a given volume through the use of a slip-ring gantry. Now that dynamic CT imaging is feasible, data may be acquired to measure tissue perfusion using a micro-CT scanner (CT Imaging, Erlangen, Germany). However, rapid imaging using micro-CT scanners leads to high image noise in individual time frames. Using the standard filtered backprojection (FBP) image reconstruction, images are prohibitively noisy for calculation of voxel-by-voxel perfusion maps. In this study, we apply prior image constrained compressed sensing (PICCS) to reconstruct images with significantly lower noise variance. In perfusion phantom experiments performed on a micro-CT scanner, the PICCS reconstruction enabled a reduction to 1/16 of the noise variance of standard FBP reconstruction, without compromising the spatial or temporal resolution. This enables a significant increase in dose efficiency, and thus, significantly less exposure time is needed to acquire images amenable to perfusion processing. This reduction in required irradiation time enables voxel-by-voxel perfusion maps to be generated on micro-CT scanners. Sample perfusion maps using a deconvolution-based perfusion analysis are included to demonstrate the improvement in image quality using the PICCS algorithm.

  4. Perfusion measurements by micro-CT using prior image constrained compressed sensing (PICCS): initial phantom results

    International Nuclear Information System (INIS)

    Nett, Brian E; Chen, G-H; Brauweiler, Robert; Kalender, Willi; Rowley, Howard

    2010-01-01

    Micro-CT scanning has become an accepted standard for anatomical imaging in small animal disease and genome mutation models. Concurrently, perfusion imaging via tracking contrast dynamics after injection of an iodinated contrast agent is a well-established tool for clinical CT scanners. However, perfusion imaging is not yet commercially available on the micro-CT platform due to limitations in both radiation dose and temporal resolution. Recent hardware developments in micro-CT scanners enable continuous imaging of a given volume through the use of a slip-ring gantry. Now that dynamic CT imaging is feasible, data may be acquired to measure tissue perfusion using a micro-CT scanner (CT Imaging, Erlangen, Germany). However, rapid imaging using micro-CT scanners leads to high image noise in individual time frames. Using the standard filtered backprojection (FBP) image reconstruction, images are prohibitively noisy for calculation of voxel-by-voxel perfusion maps. In this study, we apply prior image constrained compressed sensing (PICCS) to reconstruct images with significantly lower noise variance. In perfusion phantom experiments performed on a micro-CT scanner, the PICCS reconstruction enabled a reduction to 1/16 of the noise variance of standard FBP reconstruction, without compromising the spatial or temporal resolution. This enables a significant increase in dose efficiency, and thus, significantly less exposure time is needed to acquire images amenable to perfusion processing. This reduction in required irradiation time enables voxel-by-voxel perfusion maps to be generated on micro-CT scanners. Sample perfusion maps using a deconvolution-based perfusion analysis are included to demonstrate the improvement in image quality using the PICCS algorithm.

  5. Improvements in the technique of vascular perfusion-fixation employing a fluorocarbon-containing perfusate and a peristaltic pump controlled by pressure feedback

    DEFF Research Database (Denmark)

    Rostgaard, J; Qvortrup, Klaus; Poulsen, Steen Seier

    1993-01-01

    oxygenated fluorocarbon to glutaraldehyde perfusate-fixatives, enough oxygen is made accessible for cellular respiration as well as for the oxygen-consuming chemical reactions of glutaraldehyde with the tissue. Data on anaesthesia, operative manoeuvres, mechanical components of the system, preparation...

  6. Acute stroke: automatic perfusion lesion outlining using level sets.

    Science.gov (United States)

    Mouridsen, Kim; Nagenthiraja, Kartheeban; Jónsdóttir, Kristjana Ýr; Ribe, Lars R; Neumann, Anders B; Hjort, Niels; Østergaard, Leif

    2013-11-01

    To develop a user-independent algorithm for the delineation of hypoperfused tissue on perfusion-weighted images and evaluate its performance relative to a standard threshold method in simulated data, as well as in acute stroke patients. The study was approved by the local ethics committee, and patients gave written informed consent prior to their inclusion in the study. The algorithm identifies hypoperfused tissue in mean transit time maps by simultaneously minimizing the mean square error between individual and mean perfusion values inside and outside a smooth boundary. In 14 acute stroke patients, volumetric agreement between automated outlines and manual outlines determined in consensus among four neuroradiologists was assessed with Bland-Altman analysis, while spatial agreement was quantified by using lesion overlap relative to mean lesion volume (Dice coefficient). Performance improvement relative to a standard threshold approach was tested with the Wilcoxon signed rank test. The mean difference in lesion volume between automated outlines and manual outlines was -9.0 mL ± 44.5 (standard deviation). The lowest mean volume difference for the threshold approach was -25.8 mL ± 88.2. A significantly higher Dice coefficient was observed with the algorithm (0.71; interquartile range [IQR], 0.42-0.75) compared with the threshold approach (0.50; IQR, 0.27- 0.57; P , .001). The corresponding agreement among experts was 0.79 (IQR, 0.69-0.83). The perfusion lesions outlined by the automated algorithm agreed well with those defined manually in consensus by four experts and were superior to those obtained by using the standard threshold approach. This user-independent algorithm may improve the assessment of perfusion images as part of acute stroke treatment. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121622/-/DC1. RSNA, 2013

  7. Internet addiction: reappraisal of an increasingly inadequate concept.

    Science.gov (United States)

    Starcevic, Vladan; Aboujaoude, Elias

    2017-02-01

    This article re-examines the popular concept of Internet addiction, discusses the key problems associated with it, and proposes possible alternatives. The concept of Internet addiction is inadequate for several reasons. Addiction may be a correct designation only for the minority of individuals who meet the general criteria for addiction, and it needs to be better demarcated from various patterns of excessive or abnormal use. Addiction to the Internet as a medium does not exist, although the Internet as a medium may play an important role in making some behaviors addictive. The Internet can no longer be separated from other potentially overused media, such as text messaging and gaming platforms. Internet addiction is conceptually too heterogeneous because it pertains to a variety of very different behaviors. Internet addiction should be replaced by terms that refer to the specific behaviors (eg, gaming, gambling, or sexual activity), regardless of whether these are performed online or offline.

  8. Inadequate doses of hemodialysis. Predisposing factors, causes and prevention

    Directory of Open Access Journals (Sweden)

    Pehuén Fernández

    2017-04-01

    Full Text Available Patients receiving sub-optimal dose of hemodialysis have increased morbidity and mortality. The objectives of this study were to identify predisposing factors and causes of inadequate dialysis, and to design a practical algorithm for the management of these patients. A cross-sectional study was conducted. Ninety patients in chronic hemodialysis at Hospital Privado Universitario de Córdoba were included, during September 2015. Twenty two received sub-optimal dose of hemodialysis. Those with urea distribution volume (V greater than 40 l (72 kg body weight approximately are 11 times more likely (OR = 11.6; CI 95% = 3.2 to 51.7, p < 0.0001 to receive an inadequate dose of hemodialysis, than those with a smaller V. This situation is more frequent in men (OR = 3.5; 95% CI 1.01-15.8; p = 0.0292. V greater than 40 l was the only independent predictor of sub-dialysis in the multivariate analysis (OR = 10.3; 95% CI 2.8-37; p < 0.0004. The main cause of suboptimal dialysis was receiving a lower blood flow (Qb than the prescribed (336.4 ± 45.8 ml/min vs. 402.3 ± 28.8 ml/min respectively, p < 0.0001 (n = 18. Other causes were identified: shorter duration of the session (n = 2, vascular access recirculation (n = 1, and error in the samples (n = 1. In conclusion, the only independent predisposing factor found in this study for sub-optimal dialysis is V greater than 40 l. The main cause was receiving a slower Qb than prescribed. From these findings, an algorithm for the management of these patients was developed

  9. Evidence Report: Risk of Inadequate Human-Computer Interaction

    Science.gov (United States)

    Holden, Kritina; Ezer, Neta; Vos, Gordon

    2013-01-01

    Human-computer interaction (HCI) encompasses all the methods by which humans and computer-based systems communicate, share information, and accomplish tasks. When HCI is poorly designed, crews have difficulty entering, navigating, accessing, and understanding information. HCI has rarely been studied in an operational spaceflight context, and detailed performance data that would support evaluation of HCI have not been collected; thus, we draw much of our evidence from post-spaceflight crew comments, and from other safety-critical domains like ground-based power plants, and aviation. Additionally, there is a concern that any potential or real issues to date may have been masked by the fact that crews have near constant access to ground controllers, who monitor for errors, correct mistakes, and provide additional information needed to complete tasks. We do not know what types of HCI issues might arise without this "safety net". Exploration missions will test this concern, as crews may be operating autonomously due to communication delays and blackouts. Crew survival will be heavily dependent on available electronic information for just-in-time training, procedure execution, and vehicle or system maintenance; hence, the criticality of the Risk of Inadequate HCI. Future work must focus on identifying the most important contributing risk factors, evaluating their contribution to the overall risk, and developing appropriate mitigations. The Risk of Inadequate HCI includes eight core contributing factors based on the Human Factors Analysis and Classification System (HFACS): (1) Requirements, policies, and design processes, (2) Information resources and support, (3) Allocation of attention, (4) Cognitive overload, (5) Environmentally induced perceptual changes, (6) Misperception and misinterpretation of displayed information, (7) Spatial disorientation, and (8) Displays and controls.

  10. Preconditioning-Like Properties of Short-Term Hypothermia in Isolated Perfused Rat Liver (IPRL System

    Directory of Open Access Journals (Sweden)

    Norma Alva

    2018-03-01

    Full Text Available Hypothermia may attenuate the progression of ischemia-induced damage in liver. Here, we determined the effects of a brief cycle of hypothermic preconditioning applied before an ischemic/reperfusion (I/R episode in isolated perfused rat liver (IPRL on tissue damage and oxidative stress. Rats (male, 200–250 g were anaesthetised with sodium pentobarbital (60 mg·kg−1 i.p and underwent laparatomy. The liver was removed and perfused in a temperature-regulated non-recirculating system. Livers were randomly divided into two groups (n = 6 each group. In the hypothermia-preconditioned group, livers were perfused with hypothermic buffer (cycle of 10 min at 22 °C plus 10 min at 37 °C and the other group was perfused at 37 °C. Both groups were then submitted to 40 min of warm ischemia and 20 min of warm reperfusion. The level of tissue-damage indicators (alanine amino transferase, ALT; lactate dehydrogenase, LDH; and proteins, oxidative stress markers (thiobarbituric acid-reactive substances, TBARS; advanced oxidation protein products, AOPP; and glutathione, GSH were measured in aliquots of perfusate sampled at different time intervals. Histological determinations and oxidative stress biomarkers in homogenized liver (AOPP; TBARS; nitric oxide derivatives, NOx; GSH and glutathione disulphide, GSSG were also made in the tissue at the end. Results showed that both damage and oxidant indicators significantly decreased while antioxidant increased in hypothermic preconditioned livers. In addition, homogenized liver determinations and histological observations at the end of the protocol corroborate the results in the perfusate, confirming the utility of the perfusate as a non-invasive method. In conclusion, hypothermic preconditioning attenuates oxidative damage and appears to be a promising strategy to protect the liver against IR injury.

  11. Basic considerations in organ perfusion physiology.

    Science.gov (United States)

    Zimmerman, Michael A; Martin, Alicia; Hong, Johnny C

    2016-06-01

    Owing to a severe shortage of organs for patients with end-stage diseases, novel techniques in organ preservation and perfusion need to be studied and reviewed to increase the number of available organs for transplant. Many patients will die while waiting for an organ. To make organs from extended-criteria donors feasible, optimal conditions for pulsatile perfusion and the potential for organ reconditioning at implantation need to be addressed. Many techniques in organ preservation and perfusion are being studied. Several laboratories are studying the effects of temperature for organ perfusion. Two areas being studied are hypothermic and normothermic machine perfusion. In the area of organ preservation, new solutions are being studied such as a substrate-enriched, oxygen-saturated, and leukocyte-depleted perfusate to help with organ quality. Even with the strides being made in organ preservation and perfusion, there are still many unanswered questions. More studies will need to be done to find the optimal conditions for duration of perfusion in the cold phase, optimal perfusion solution, degree of oxygenation, and the addition of pharmacologic agents, to improve organ function and expand the organ pool.

  12. Assessment of foot perfusion in patients with a diabetic foot ulcer.

    Science.gov (United States)

    Forsythe, Rachael O; Hinchliffe, Robert J

    2016-01-01

    Assessment of foot perfusion is a vital step in the management of patients with diabetic foot ulceration, in order to understand the risk of amputation and likelihood of wound healing. Underlying peripheral artery disease is a common finding in patients with foot ulceration and is associated with poor outcomes. Assessment of foot perfusion should therefore focus on identifying the presence of peripheral artery disease and to subsequently estimate the effect this may have on wound healing. Assessment of perfusion can be difficult because of the often complex, diffuse and distal nature of peripheral artery disease in patients with diabetes, as well as poor collateralisation and heavy vascular calcification. Conventional methods of assessing tissue perfusion in the peripheral circulation may be unreliable in patients with diabetes, and it may therefore be difficult to determine the extent to which poor perfusion contributes to foot ulceration. Anatomical data obtained on cross-sectional imaging is important but must be combined with measurements of tissue perfusion (such as transcutaneous oxygen tension) in order to understand the global and regional perfusion deficit present in a patient with diabetic foot ulceration. Ankle-brachial pressure index is routinely used to screen for peripheral artery disease, but its use in patients with diabetes is limited in the presence of neuropathy and medial arterial calcification. Toe pressure index may be more useful because of the relative sparing of pedal arteries from medial calcification but may not always be possible in patients with ulceration. Fluorescence angiography is a non-invasive technique that can provide rapid quantitative information about regional tissue perfusion; capillaroscopy, iontophoresis and hyperspectral imaging may also be useful in assessing physiological perfusion but are not widely available. There may be a future role for specialized perfusion imaging of these patients, including magnetic resonance

  13. Assessment value of quantitative indexes of pancreatic CT perfusion scanning for malignant degree of pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Jiang-Xia Lei

    2016-10-01

    Full Text Available Objective: To analyze the assessment value of the quantitative indexes of pancreatic CT perfusion scanning for malignant degree of pancreatic cancer. Methods: A total of 58 patients with space-occupying pancreatic lesions were divided into 20 patients with pancreatic cancer and 38 patients with benign pancreatic lesions after pancreatic CT perfusion. Patients with pancreatic cancer received palliative surgery, and the cancer tissue and para-carcinoma tissue specimens were collected during operation. The differences in pancreatic CT perfusion scanning parameter values and serum tumor marker levels were compared between patients with pancreatic cancer and patients with benign pancreatic lesions, mRNA expression levels of malignant molecules in pancreatic cancer tissue and para-carcinoma tissue were further determined, and the correlation between pancreatic CT perfusion scanning parameter values and malignant degree of pancreatic cancer was analyzed. Results: CT perfusion scanning BF, BV and Per values of patients with pancreatic cancer were lower than those of patients with benign pancreatic lesions; serum CA19-9, CEA, CA125 and CA242 levels were higher than those of patients with benign pancreatic lesions (P<0.05; mRNA expression levels of Bcl-2, Bcl-xL and survivin in pancreatic cancer tissue samples were higher than those in paracarcinoma tissue samples, and mRNA expression levels of P53 and Bax were lower than those in para-carcinoma tissue samples (P<0.05; CT perfusion scanning parameters BF, BV and Per values of patients with pancreatic cancer were negatively correlated with CA19-9, CEA, CA125 and CA242 levels in serum as well as mRNA expression levels of Bcl-2, Bcl-xL and survivin in pancreatic cancer tissue, and positively correlated with mRNA expression levels of P53 and Bax in pancreatic cancer tissue (P<0.05. Conclusions: Pancreatic CT perfusion scanning is a reliable way to judge the malignant degree of pancreatic cancer and plays a

  14. [MSCT perfusion imaging and its correlation with perfusion parameters, survivin expression, MVD, and pathologic grade in hepatocellular carcinomas].

    Science.gov (United States)

    Long, Xueying; Cao, Jue; Shi, Linbo; Li, Wenzheng; Liu, Hui

    2009-11-01

    (1)To obtain the perfusion parameters of hepatocellular carcinomas(HCCs), peritumour livers and normal livers by multi-slice CT(MSCT)and to investigate their characteristics and clinical significances;(2)To investigate the correlation among perfusion parameters, survivin expression, microvessel density(MVD)and pathologic grade of HCCs. A total of 31 patients with HCC (5 well-differentiated HCCs, 17 moderately differentiated HCCs, and 9 poorly differentiated HCCs) and 10 normal liver were studied. All underwent CT plain scan, perfusion scan, and conventional enhancement scan of the whole liver using 16-slice spiral CT (Philips Brilliance 16). Perfusion parameters were obtained by time-density curves (TDC) of region of interest (ROI) through the perfusion scans. Tissue sections of HCCs and their corresponding peritumour liver tissues of the 31 patients were detected by immunohistochemistry (SABC methods) for protein expression of survivin and MVD, and 10 normal liver tissue sections were as used as negative controls. The correlation among the perfusion parameters, survivin expression, MVD and pathology grade were analysed. (1)The mean values of HAP, HPP, TLP, and HAI of HCCs were 27.50 mL/(min.100 mL), 19.37 mL/(min.100 mL), 46.87 mL/(min.100 mL), and 60.38%, respectively. The mean values of those of the peritumour livers were 14.93 mL/(min.100 mL), 55.70 mL/(min.100 mL), 69.63 mL/(min.100 mL), and 21.51%, respectively. The mean value of those of the normal livers were 12.22 mL/(min.100mL), 74.56 mL/(min.100 mL), 86.78 mL/(min.100 mL), and 14.00%, respectively. The values of HAP and HAI of HCCs were significantly higher than those of the peritumor livers and the normal livers(PHAP and decrease of HPP of peritumor livers were both significant compared with that of the normal livers(PHAP, HPP, and HAI of HCCs were significantly different from those of peritumor livers (Pcancerous adjacent liver tissues and normal liver tissues (PHAP values were significantly and

  15. Morphological, contrast-enhanced and spin labeling perfusion imaging for monitoring of relapse after RF ablation of renal cell carcinomas

    International Nuclear Information System (INIS)

    Boss, Andreas; Martirosian, Petros; Schraml, Christina; Schick, Fritz; Clasen, Stephan; Fenchel, Michael; Claussen, Claus D.; Pereira, Philippe L.; Anastasiadis, Artistotelis

    2006-01-01

    MR perfusion imaging was applied for the assessment of completeness in the destruction of renal cell carcinomas by RF ablation (RFA) in a pilot study. An arterial spin labeling (ASL) approach was compared to conventional contrast-enhanced T1-weighted (CE-T1w) imaging. Ten patients suffering from renal cell carcinoma were treated by RFA. For the assessment of the extent of coagulation and for the detection of residual tumor, T1-weighted gradient-echo imaging, T2-weighted spin echo imaging and two different perfusion imaging techniques were performed before, 1 day and 6 weeks after RFA at 1.5 T. Perfusion imaging comprised CE-T1 weighted and FAIR-TrueFISP ASL imaging. Perfusion images recorded in the acute stage after RFA showed higher compliance to the definitive ablation volume reached after 6 weeks than T2-weighted images, which underestimated the true necrosis size. In the detection of residual tumor tissue, both modalities complimented each other. The exclusion of residual tumor tissue could more reliably be performed using perfusion-imaging methods. Both perfusion-imaging modalities showed sufficient imaging quality for post-interventional monitoring. Perfusion imaging provides a higher predictability of the completeness of tumor ablation and extent of coagulation than T2-weighted imaging alone. Since the results of the FAIR-TrueFISP sequence are promising, the administration of potentially nephrotoxic contrast media may be avoided in the respective patient cohort. (orig.)

  16. Initial treatment of severe malaria in children is inadequate – a study ...

    African Journals Online (AJOL)

    -medicated at home. Initial consultations are at primary local health facilities where less effective drugs are prescribed at inadequate dosages. Recommended ACTs were also often prescribed at inadequate dosages. Education in the use of ...

  17. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H

    2014-01-01

    the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced...... dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2...

  18. Analysis of blood flow in a third ventricular ependymoma and an olfactory bulb meningioma by usisng perfusion computed tomography

    International Nuclear Information System (INIS)

    Kishimoto, M.; Yamada, K.; Seok, J.S.; Shimizu, J.; Kobayashi, Y.; Akiba, Y.; Morishita, Y.; Iwasa, A.; Iwasaki, T.; Miyake, Y.

    2008-01-01

    Brain perfusion computed tomography (CT) scanning was performed in a mongrel dog and a golden retriever that were diagnosed with third ventricular tumor and olfactory bulb tumor, respectively, by contrast-enhanced CT. The tumors were pathologically diagnosed as ependymoma and meningioma, respectively. Perfusion CT results revealed that the ependymoma in this study had a lower blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Further, the meningioma in this study had a higher blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Perfusion CT can potentially be used for the grading of brain tumors and narrowing differential diagnosis, provided the perfusion CT data of animals are accumulated

  19. The role of preservation solution on acid-base regulation during machine perfusion of kidneys.

    Science.gov (United States)

    Baicu, Simona C; Taylor, Michael J; Brockbank, Kelvin G M

    2006-01-01

    To meet the current clinical organ demand, efficient preservation methods and solutions are needed to increase the number of viable kidneys for transplantation. In the present study, the influence of perfusion solution buffering strength on renal pH dynamics and regulation mechanisms during kidney ex vivo preservation was determined. Porcine kidneys were hypothermically machine perfused for 72 h with either Unisol-UHK or Belzer-Machine Perfusion solution, Belzer-MP solution. Renal perfusate samples were periodically collected and biochemically analyzed. The UHK solution, a Hepes-based solution (35 mM), provided a more efficient control of renal pH that, in turn, resulted in minor changes in the perfusate pH relative to baseline, in response to tissue CO2 and HCO3- production. In the perfusate of Belzer-MP kidney group a wider range of pH values were recorded and a pronounced pH reduction was seen in response to significant rises in pCO2 and HCO3- concentrations. The Belzer-MP solution, containing phosphate (25 mM) as its main buffer, and only 10 mM Hepes, had a greater buffering requirement to attenuate larger pH changes.

  20. Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-03-01

    blood flow estimation. In conclusion, quantitative model-based dynamic cardiac CT perfusion assessment is capable of accurately estimating MBF across a range of cardiac outputs and tissue perfusion states, outperforms comparable static perfusion estimates, and is relatively robust to noise and temporal subsampling.

  1. Newcastle disease virus outbreaks: vaccine mismatch or inadequate application?

    Science.gov (United States)

    Dortmans, Jos C F M; Peeters, Ben P H; Koch, Guus

    2012-11-09

    Newcastle disease (ND) is one of the most important diseases of poultry, and may cause devastating losses in the poultry industry worldwide. Its causative agent is Newcastle disease virus (NDV), also known as avian paramyxovirus type 1. Many countries maintain a stringent vaccination policy against ND, but there are indications that ND outbreaks can still occur despite intensive vaccination. It has been argued that this may be due to antigenic divergence between the vaccine strains and circulating field strains. Here we present the complete genome sequence of a highly virulent genotype VII virus (NL/93) obtained from vaccinated poultry during an outbreak of ND in the Netherlands in 1992-1993. Using this strain, we investigated whether the identified genetic evolution of NDV is accompanied by antigenic evolution. In this study we show that a live vaccine that is antigenically adapted to match the genotype VII NL/93 outbreak strain does not provide increased protection compared to a classic genotype II live vaccine. When challenged with the NL/93 strain, chickens vaccinated with a classic vaccine were completely protected against clinical disease and mortality and virus shedding was significantly reduced, even with a supposedly suboptimal vaccine dose. These results suggest that it is not antigenic variation but rather poor flock immunity due to inadequate vaccination practices that may be responsible for outbreaks and spreading of virulent NDV field strains. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. FAIR true-FISP perfusion imaging of the kidneys.

    Science.gov (United States)

    Martirosian, Petros; Klose, Uwe; Mader, Irina; Schick, Fritz

    2004-02-01

    Most arterial spin labeling (ASL) techniques apply echoplanar imaging (EPI) because this strategy provides relatively high SNR in short measuring times. Unfortunately, those techniques are very susceptible to static magnetic field inhomogeneities and perfusion signals from organs with fast transverse relaxation might decrease due to the exchange of water molecules in capillaries and organ tissue combined with relatively long echo times of EPI sequences. To overcome these problems a novel imaging technique, FAIR True-FISP, was developed. It combines a FAIR (flow-sensitive alternating inversion recovery) perfusion preparation and a true fast imaging with steady precession (True-FISP) data acquisition strategy. True-FISP was chosen since this sequence type does not show the mentioned disadvantages of EPI, but provides a similar SNR per measuring time. An important problem of this approach is that True-FISP sequences usually work in a steady state which is independent of a previous preparation of magnetization. For this reason a sequence structure had to be developed which keeps the advantages of True-FISP and makes the signal intensity sensitive to the FAIR preparation. Breathhold and nonbreathhold examinations of kidneys are presented and possible strategies to quantitative flow measurements are reported. It is shown that correction of spatially inhomogeneous receiver coil characteristics is easily feasible and leads to clinically valuable perfusion examinations of kidneys without application of potentially nephrotoxic contrast media. Copyright 2004 Wiley-Liss, Inc.

  3. A microfluidically perfused three dimensional human liver model.

    Science.gov (United States)

    Rennert, Knut; Steinborn, Sandra; Gröger, Marko; Ungerböck, Birgit; Jank, Anne-Marie; Ehgartner, Josef; Nietzsche, Sandor; Dinger, Julia; Kiehntopf, Michael; Funke, Harald; Peters, Frank T; Lupp, Amelie; Gärtner, Claudia; Mayr, Torsten; Bauer, Michael; Huber, Otmar; Mosig, Alexander S

    2015-12-01

    Within the liver, non-parenchymal cells (NPCs) are critically involved in the regulation of hepatocyte polarization and maintenance of metabolic function. We here report the establishment of a liver organoid that integrates NPCs in a vascular layer composed of endothelial cells and tissue macrophages and a hepatic layer comprising stellate cells co-cultured with hepatocytes. The three-dimensional liver organoid is embedded in a microfluidically perfused biochip that enables sufficient nutrition supply and resembles morphological aspects of the human liver sinusoid. It utilizes a suspended membrane as a cell substrate mimicking the space of Disse. Luminescence-based sensor spots were integrated into the chip to allow online measurement of cellular oxygen consumption. Application of microfluidic flow induces defined expression of ZO-1, transferrin, ASGPR-1 along with an increased expression of MRP-2 transporter protein within the liver organoids. Moreover, perfusion was accompanied by an increased hepatobiliary secretion of 5(6)-carboxy-2',7'-dichlorofluorescein and an enhanced formation of hepatocyte microvilli. From this we conclude that the perfused liver organoid shares relevant morphological and functional characteristics with the human liver and represents a new in vitro research tool to study human hepatocellular physiology at the cellular level under conditions close to the physiological situation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Liver perfusion in sepsis, septic shock, and multiorgan failure.

    Science.gov (United States)

    Spapen, Herbert

    2008-06-01

    Sepsis causes significant alterations in the hepatic macro- and microcirculation. Diverging views exist on global hepatic blood flow during experimental sepsis because of the large variety in animal and sepsis models. Fluid-resuscitated clinical sepsis is characterized by ongoing liver ischemia due to a defective oxygen extraction despite enhanced perfusion. The effects of vasoactive agents on the hepatosplanchnic circulation are variable, mostly anecdotal, and depend on baseline perfusion, time of drug administration, and use of concomitant medication. Microvascular blood flow disturbances are thought to play a pivotal role in the development of sepsis-induced multiorgan failure. Redistribution of intrahepatic blood flow in concert with a complex interplay between sinusoidal endothelial cells, liver macrophages, and passing leukocytes lead to a decreased perfusion and blood flow velocity in the liver sinusoids. Activation and dysfunction of the endothelial cell barrier with subsequent invasion of neutrophils and formation of microthrombi further enhance liver tissue ischemia and damage. Substances that regulate (micro)vascular tone, such as nitric oxide, endothelin-1, and carbon monoxide, are highly active during sepsis. Possible interactions between these mediators are not well understood, and their therapeutic manipulation produces equivocal or disappointing results. Whether and how standard resuscitation therapy influences the hepatic microvascular response to sepsis is unknown. Indirect evidence supports the concept that improving the microcirculation may prevent or ameliorate sepsis-induced organ failure.

  5. Brain perfusion-CT in acute stroke patients

    International Nuclear Information System (INIS)

    Andreev, T.; Totsev, N.; Tzvetanov, P.

    2013-01-01

    Since 1979 when Grodfrey Hounsfield and Allan Corman introduced the computed tomography new generations of CT were developed that improved the special resolution and time of acquisition. The role of neuro-imaging in the evaluation of acute stroke has changed dramatically in the past decade. Previously, neuro-imaging was used in this set-ting to provide anatomic imaging that indicated the presence or absence of acute cerebral ischemia and excluded lesions that produce symptoms or signs mimicking those of stroke, such as hemorrhage and neoplasms. More recently, the introduction of thrombolysis has changed the goals of neuro-imaging from providing solely anatomic information to providing physiologic information that could help to determine which patients might benefit from therapy. In particular, significant emphasis has been placed on the delineation of the ischemic penumbra, also called tissue at risk. Modem CT survey, consisting of three indissociable elements; noncontrast CT (NCT) of course, perfusion-CT (PCT) and CT-angiography (CTA), fulfill all the requirements for hyperacute stroke imaging. CTA can define the occlusion site, depict arterial dissection, grade collateral blood flow, and characterize atherosclerotic disease, whereas PCT accurately defines the infarct core and the ischemic penumbra. CT offers a number of practical advantages over other cerebral perfusion imaging methods, including its wide availability. Using PCT and CTA to define new individualized strategies for acute reperfusion will allow more acute stroke patients to benefit from thrombolytic therapy. Key words: Stroke. Penumbra. Computed Tomography. Perfusion-CT. CT Angiography. Outcome

  6. A non-linear regression method for CT brain perfusion analysis

    Science.gov (United States)

    Bennink, E.; Oosterbroek, J.; Viergever, M. A.; Velthuis, B. K.; de Jong, H. W. A. M.

    2015-03-01

    CT perfusion (CTP) imaging allows for rapid diagnosis of ischemic stroke. Generation of perfusion maps from CTP data usually involves deconvolution algorithms providing estimates for the impulse response function in the tissue. We propose the use of a fast non-linear regression (NLR) method that we postulate has similar performance to the current academic state-of-art method (bSVD), but that has some important advantages, including the estimation of vascular permeability, improved robustness to tracer-delay, and very few tuning parameters, that are all important in stroke assessment. The aim of this study is to evaluate the fast NLR method against bSVD and a commercial clinical state-of-art method. The three methods were tested against a published digital perfusion phantom earlier used to illustrate the superiority of bSVD. In addition, the NLR and clinical methods were also tested against bSVD on 20 clinical scans. Pearson correlation coefficients were calculated for each of the tested methods. All three methods showed high correlation coefficients (>0.9) with the ground truth in the phantom. With respect to the clinical scans, the NLR perfusion maps showed higher correlation with bSVD than the perfusion maps from the clinical method. Furthermore, the perfusion maps showed that the fast NLR estimates are robust to tracer-delay. In conclusion, the proposed fast NLR method provides a simple and flexible way of estimating perfusion parameters from CT perfusion scans, with high correlation coefficients. This suggests that it could be a better alternative to the current clinical and academic state-of-art methods.

  7. Ex Vivo Dual Perfusion of the Human Placenta: Disease Simulation, Therapeutic Pharmacokinetics and Analysis of Off-Target Effects.

    Science.gov (United States)

    Brownbill, Paul; Sebire, Neil; McGillick, Erin V; Ellery, Stacey; Murthi, Padma

    2018-01-01

    In recent years ex vivo dual perfusion of the human placental lobule is seeing an international renaissance in its application to understanding fetal health and development. Here, we discuss the methods and uses of this technique in the evaluation of (1) vascular function, (2) transplacental clearance, (3) hemodynamic and oxygenation changes associated with pregnancy complications on placental structure and function, and (4) placental toxicology and post-perfusion evaluation of tissue architecture.

  8. Clinical application of cerebral dynamic perfusion studies

    International Nuclear Information System (INIS)

    DeLand, F.H.

    1975-01-01

    Radionuclide cerebral perfusion studies are assuming a far greater importance in the detection and differential diagnosis of cerebral lesions. Perfusion studies not only contribute to the differential diagnosis of lesions but in certain cases are the preferred methods by which more accurate clinical interpretations can be made. The characteristic blood flow of arterio-venous malformations readily differentiates this lesion from neoplasms. The decreased perfusion or absent perfusion observed in cerebral infarctions is diagnostic without concurrent evidence from static images. Changes in rates and direction of blood flow contribute fundamental information to the status of stenosis and vascular occlusion and, in addition, offer valuable information on the competency and routes of collateral circulation. The degree of cerebral perfusion after cerebral vascular accidents appears to be directly related to patient recovery, particularly muscular function. Cerebral perfusion adds a new parameter in the diagnosis of subdural haematomas and concussion and in the differentiation of obscuring radioactivity from superficial trauma. Although pictorial displays of perfusion blood flow will offer information in most cerebral vascular problems, the addition of computer analysis better defines temporal relationships of regional blood flow, quantitative changes in flow and the detection of the more subtle increases or decreases in cerebral blood flow. The status of radionuclide cerebral perfusion studies has taken on an importance making it the primary modality for the diagnosis of cerebral lesions. (author)

  9. Arterial spin labelling perfusion MRI of breast cancer using FAIR TrueFISP: Initial results

    International Nuclear Information System (INIS)

    Buchbender, S.; Obenauer, S.; Mohrmann, S.; Martirosian, P.; Buchbender, C.; Miese, F.R.; Wittsack, H.J.; Miekley, M.; Antoch, G.; Lanzman, R.S.

    2013-01-01

    Aim: To assess the feasibility of an unenhanced, flow-sensitive, alternating inversion recovery-balanced steady-state free precession (FAIR TrueFISP) arterial spin labelling (ASL) magnetic resonance imaging (MRI) technique for quantification of breast cancer perfusion. Materials and methods: Eighteen untreated breast tumour patients (mean age 53 ± 17 years, range 30–68 years) and four healthy controls (mean age 51 ± 14 years, range 33–68 years) were enrolled in this study and were imaged using a clinical 1.5 T MRI machine. Perfusion measurements were performed using a coronal single-section ASL FAIR TrueFISP technique in addition to a routine breast MRI examination. T1 relaxation time of normal breast parenchyma was determined in four healthy volunteers using the variable flip angle approach. The definitive diagnosis was obtained at histology after biopsy or surgery and was available for all patients. Results: ASL perfusion was successfully acquired in 13 of 18 tumour patients and in all healthy controls. The mean ASL perfusion of invasive ductal carcinoma tissue was significantly higher (88.2 ± 39.5 ml/100 g/min) compared to ASL perfusion of normal breast parenchyma (24.9 ± 12.7 ml/100 g/min; p < 0.05) and invasive lobular carcinoma (30.5 ± 4.3 ml/100 g/min; p < 0.05). No significant difference was found between the mean ASL perfusion of normal breast parenchyma and invasive lobular carcinoma tissue (p = 0.97). Conclusion: ASL MRI enables quantification of breast cancer perfusion without the use of contrast material. However, its impact on diagnosis and therapy management of breast tumours has to be evaluated in larger patient studies

  10. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators......Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over......, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices...

  11. Quantification of brain perfusion with tracers retained by the brain

    Energy Technology Data Exchange (ETDEWEB)

    Pupi, A.; Bacciottini, L.; De Cristofaro, M.T.R.; Formiconi, A.R.; Castagnoli, A. [Univ. of Florence (Italy)

    1991-12-31

    Almost a decade ago, tracers, labelled with {sup 123}I and {sup 99m}Tc, that are retained by the brain, started to be used for studies of regional brain perfusion (regional cerebral blood flow, rCBF). To date, these tracers have been used for brain perfusion imaging with SPECT in brain disorders as well as for physiological activation protocols. Only seldom, however, have they been used in protocols that quantitatively measure rCBF. Nevertheless, comparative studies with perfusion reference tracers have repeatedly demonstrated that the brain uptake of these brain-retained tracers is correlated to perfusion, the major determinant of the distribution of these tracers in the brain. The brain kinetics of {sup 99m}Tc HMPAO, which is the tracer most commonly used, was described with a two-compartment tissue model. The theoretical approach, which is, in itself, sufficient for modeling quantitative measurements with {sup 99m}Tc HMPAO, initially suggested the possibility of empirically narrowing the distance between the brain`s regional uptake of the tracer and rCBF with a linearization algorithm which uses the cerebellum as the reference region. The value of this empirical method is hampered by the fact that the cerebellum can be involved in cerebrovascular disease (i.e. cerebellar diaschisis) as well as in several other brain disorders (e.g. anxiety, and dementia of the Alzheimer type). It also was proposed that different reference regions (occipital, whole slice, or whole brain) should be selected in relation to the brain disorder under study. However, this approach does not solve the main problem because it does not equip us with a reliable tool to evaluate rCBF with a high predictive value, and, at the same time, to reduce intersubject variability. The solution would be to measure a quantitative parameter which directly reflects rCBF, such as the unidirectional influx constant of the freely diffusible flow-limited tracers. 45 refs., 3 figs., 1 tab.

  12. Simultaneous measurement of pO2 and perfusion in the rabbit kidney in vivo.

    Science.gov (United States)

    O'Connor, Paul M; Anderson, Warwick P; Kett, Michelle M; Evans, Roger G

    2007-01-01

    Recently, a combined probe has been developed capable of simultaneous measurement of local tissue pO2 (fluorescence oximetry) and microvascular perfusion (laser Doppler flux) within the same local region. The aim of the current study was to test the utility of these combined probes to measure pO2 and perfusion in the kidney. Studies were performed in anesthetized, artificially ventilated rabbits (n=7). Baseline measurements of renal medullary perfusion and pO2 obtained using combined probes (537 +/- 110 units & 28.7 +/- 6.l mmHg, respectively) were indistinguishable from those obtained using independent probes (435 +/- 102 units & 26.9 +/- 6.4 mmHg). Baseline measurements of renal cortical pO2 were also similar between combined (9.7 +/- 1.6 mmHg) and independent probes (9.5 +/- 2.3 mmHg). Baseline levels of cortical perfusion however, were significantly greater when measured using independent probes (1130 +/- 114 units) compared to combined probes (622 +/- 59 units; P pO2 resulting from graded stimulation of the renal nerves were not significantly different when measured using combined probes to those obtained using independent probes. We conclude that combined probes are equally suitable to independent probes for tissue pO2 and microvascular perfusion measurement in the kidney. Our results raise some concerns regarding the accuracy of these OxyLite fluorescence probes for pO2 measurement in the kidney, particularly within the renal cortex.

  13. Industrialization of a perfusion bioreactor: Prime example of a non-straightforward process.

    Science.gov (United States)

    Talò, G; Turrisi, C; Arrigoni, C; Recordati, C; Gerges, I; Tamplenizza, M; Cappelluti, A; Riboldi, S A; Moretti, M

    2018-02-01

    Bioreactors are essential enabling technologies for the translation of advanced therapies medicinal products from the research field towards a successful clinical application. In order to speed up the translation and the spread of novel tissue engineering products into the clinical routine, tissue engineering bioreactors should evolve from laboratory prototypes towards industrialized products. In this work, we thus challenged the industrialization process of a novel technological platform, based on an established research prototype of perfusion bioreactor, following a GMP-driven approach. We describe how the combination of scientific background, intellectual property, start-up factory environment, wise industrial advice in the biomedical field, design, and regulatory consultancy allowed us to turn a previously validated prototype technology into an industrial product suitable for serial production with improved replicability and user-friendliness. The solutions implemented enhanced aesthetics, ergonomics, handling, and safety of the bioreactor, and they allowed compliance with the fundamental requirements in terms of traceability, reproducibility, efficiency, and safety of the manufacturing process of advanced therapies medicinal products. The result is an automated incubator-compatible device, housing 12 disposable independent perfusion chambers for seeding and culture of any perfusable tissue. We validated the cell seeding process of the industrialized bioreactor by means of the Design of Experiment approach, whilst the effectiveness of perfusion culture was evaluated in the context of bone tissue engineering. Copyright © 2017 John Wiley & Sons, Ltd.

  14. Initial intramuscular perfusion pressure predicts early skeletal muscle function following isolated tibial fractures

    Directory of Open Access Journals (Sweden)

    Haas Norbert P

    2008-04-01

    Full Text Available Abstract Background The severity of associated soft tissue trauma in complex injuries of the extremities guides fracture treatment and decisively determines patient's prognosis. Trauma-induced microvascular dysfunction and increased tissue pressure is known to trigger secondary soft tissue damage and seems to adversely affect skeletal muscle function. Methods 20 patients with isolated tibial fractures were included. Blood pressure and compartment pressure (anterior and deep posterior compartment were measured continuously up to 24 hours. Corresponding perfusion pressure was calculated. After 4 and 12 weeks isokinetic muscle peak torque and mean power of the ankle joint in dorsal and plantar flexion were measured using a Biodex dynamometer. Results A significant inverse correlation between the anterior perfusion pressure at 24 hours and deficit in dorsiflexion at 4 weeks was found for both, the peak torque (R = -0.83; p Conclusion The functional relationship between the decrease in intramuscular perfusion pressures and muscle performance in the early rehabilitation period indicate a causative and prognostic role of early posttraumatic microcirculatory derangements and skeletal muscle function. Therapeutic concepts aimed at effective muscle recovery, early rehabilitation, and decreased secondary tissue damage, should consider the maintenance of an adequate intramuscular perfusion pressure.

  15. Correlation analysis of dual-energy CT iodine maps with quantitative pulmonary perfusion MRI.

    Science.gov (United States)

    Hansmann, Jan; Apfaltrer, Paul; Zoellner, Frank G; Henzler, Thomas; Meyer, Mathias; Weisser, Gerald; Schoenberg, Stefan O; Attenberger, Ulrike I

    2013-05-28

    To correlate dual-energy computed tomography (DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging (MRI). Eighteen patients with pulmonary perfusion defects detected on DECT derived iodine maps were included in this prospective study and additionally underwent time-resolved contrast-enhanced pulmonary MRI [dynamic contrast enhanced (DCE)-MRI]. DCE-MRI data were quantitatively analyzed using a pixel-by-pixel deconvolution analysis calculating regional pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) in visually normal lung parenchyma and perfusion defects. Perfusion parameters were correlated to mean attenuation values of normal lung and perfusion defects on DECT iodine maps. Two readers rated the concordance of perfusion defects in a visual analysis using a 5-point Likert-scale (1 = no correlation, 5 = excellent correlation). In visually normal pulmonary tissue mean DECT and MRI values were: 22.6 ± 8.3 Hounsfield units (HU); PBF: 58.8 ± 36.0 mL/100 mL per minute; PBV: 16.6 ± 8.5 mL; MTT: 17.1 ± 10.3 s. In areas with restricted perfusion mean DECT and MRI values were: 4.0 ± 3.9 HU; PBF: 10.3 ± 5.5 mL/100 mL per minute, PBV: 5 ± 4 mL, MTT: 21.6 ± 14.0 s. The differences between visually normal parenchyma and areas of restricted perfusion were statistically significant for PBF, PBV and DECT (P < 0.0001). No linear correlation was found between MRI perfusion parameters and attenuation values of DECT iodine maps (PBF: r = 0.35, P = 0.15; PBV: r = 0.34, P = 0.16; MTT: r = 0.41, P = 0.08). Visual analysis revealed a moderate correlation between perfusion defects on DECT iodine maps and the parameter maps of DCE-MRI (mean score 3.6, κ 0.45). There is a moderate visual but not statistically significant correlation between DECT iodine maps and perfusion parameter maps of DCE-MRI.

  16. Critical cerebral perfusion pressure at high intracranial pressure measured by induced cerebrovascular and intracranial pressure reactivity.

    Science.gov (United States)

    Bragin, Denis E; Statom, Gloria L; Yonas, Howard; Dai, Xingping; Nemoto, Edwin M

    2014-12-01

    The lower limit of cerebral blood flow autoregulation is the critical cerebral perfusion pressure at which cerebral blood flow begins to fall. It is important that cerebral perfusion pressure be maintained above this level to ensure adequate cerebral blood flow, especially in patients with high intracranial pressure. However, the critical cerebral perfusion pressure of 50 mm Hg, obtained by decreasing mean arterial pressure, differs from the value of 30 mm Hg, obtained by increasing intracranial pressure, which we previously showed was due to microvascular shunt flow maintenance of a falsely high cerebral blood flow. The present study shows that the critical cerebral perfusion pressure, measured by increasing intracranial pressure to decrease cerebral perfusion pressure, is inaccurate but accurately determined by dopamine-induced dynamic intracranial pressure reactivity and cerebrovascular reactivity. Cerebral perfusion pressure was decreased either by increasing intracranial pressure or decreasing mean arterial pressure and the critical cerebral perfusion pressure by both methods compared. Cortical Doppler flux, intracranial pressure, and mean arterial pressure were monitored throughout the study. At each cerebral perfusion pressure, we measured microvascular RBC flow velocity, blood-brain barrier integrity (transcapillary dye extravasation), and tissue oxygenation (reduced nicotinamide adenine dinucleotide) in the cerebral cortex of rats using in vivo two-photon laser scanning microscopy. University laboratory. Male Sprague-Dawley rats. At each cerebral perfusion pressure, dopamine-induced arterial pressure transients (~10 mm Hg, ~45 s duration) were used to measure induced intracranial pressure reactivity (Δ intracranial pressure/Δ mean arterial pressure) and induced cerebrovascular reactivity (Δ cerebral blood flow/Δ mean arterial pressure). At a normal cerebral perfusion pressure of 70 mm Hg, 10 mm Hg mean arterial pressure pulses had no effect on

  17. The association of xerostomia and inadequate intake in older adults.

    Science.gov (United States)

    Rhodus, N L; Brown, J

    1990-12-01

    Recent studies indicate that nearly one in five older adults has xerostomia (dry mouth). Salivary gland dysfunction and/or inadequate saliva increases the difficulty of these older adults in obtaining proper nutrition. Problems in lubricating, masticating, tolerating, tasting, and swallowing food contribute notably to the complex physiological and psychological manifestations of aging. To our knowledge, the literature has not demonstrated an association between xerostomia and malnutrition in the elderly. We randomly selected 67 older adults from institutionalized and free-living geriatric populations. Nutritional intake analysis was performed on both groups of study subjects, who were found to have xerostomia by use of sialometry, and on control subjects matched for age, sex, and physical status. Intake of total energy, protein, dietary fiber, total fat, saturated fat, cholesterol, sodium, potassium, vitamin A, vitamin C, thiamin, riboflavin, vitamin B-6, calcium, iron, and zinc was compared with the 1989 Recommended Dietary Allowances. Subjects' intakes were also compared with that of a control group. Medical systemic information and number and types of medications were compared among the groups. Statistical analysis of the data indicated significant (p less than .001) inadequacies in the nutritional intake patterns of institutionalized and free-living older adults with xerostomia. Subjects with xerostomia (more than 75% of the free-living and institutionalized seniors) had significant deficiencies of fiber, potassium, vitamin B-6, iron, calcium, and zinc. Taste and food perception were significantly reduced in the elders with xerostomia. Our study indicates the potential contribution of xerostomia to the high prevalence of geriatric malnutrition in the United States.

  18. Inadequate pain relief among patients with primary knee osteoarthritis.

    Science.gov (United States)

    Laires, Pedro A; Laíns, Jorge; Miranda, Luís C; Cernadas, Rui; Rajagopalan, Srini; Taylor, Stephanie D; Silva, José C

    Despite the widespread treatments for osteoarthritis (OA), data on treatment patterns, adequacy of pain relief, and quality of life are limited. The prospective multinational Survey of Osteoarthritis Real World Therapies (SORT) was designed to investigate these aspects. To analyze the characteristics and the patient reported outcomes of the Portuguese dataset of SORT at the start of observation. Patients ≥50 years with primary knee OA who were receiving oral or topical analgesics were eligible. Patients were enrolled from seven healthcare centers in Portugal between January and December 2011. Pain and function were evaluated using the Brief Pain Inventory (BPI) and WOMAC. Quality of life was assessed using the 12-Item Short Form Health Survey (SF-12). Inadequate pain relief (IPR) was defined as a score >4/10 on item 5 of the BPI. Overall, 197 patients were analyzed. The median age was 67.0 years and 78.2% were female. Mean duration of knee OA was 6.2 years. IPR was reported by 51.3% of patients. Female gender (adjusted odds ratio - OR 2.15 [95%CI 1.1, 4.5]), diabetes (OR 3.1 [95%CI 1.3, 7.7]) and depression (OR 2.24 [95%CI 1.2, 4.3]) were associated with higher risk of IPR. Patients with IPR reported worst outcomes in all dimensions of WOMAC (p<0.001) and in all eight domains and summary components of SF-12 (p<0.001). Our findings indicate that improvements are needed in the management of pain in knee OA in order to achieve better outcomes in terms of pain relief, function and quality of life. Copyright © 2016 Elsevier Editora Ltda. All rights reserved.

  19. Pre-bisection of a single skin biopsy does not produce technically inadequate specimens for direct immunofluorescence: a review of 3450 specimens.

    Science.gov (United States)

    Loh, Ern; Armstrong, April W; Fung, Maxwell A

    2014-11-01

    Evaluation of a potential immunobullous disorder typically requires two pieces of tissue obtained by skin biopsy: one placed in formalin for conventional microscopy and a second placed in a different transport medium suitable for direct immunofluorescence (DIF) testing. Clinical practice in this area is not standardized, with dermatologists either obtaining two biopsies or dividing (pre-bisecting) a single biopsy. Some DIF specimens are technically inadequate for interpretation of subepidermal imunobullous disorders because the basement membrane zone is not intact, but it is unknown whether pre-bisecting the tissue increases the risk of compromising the specimen. To investigate whether technically inadequate DIF specimens are associated with pre-bisection. DIF specimens were consecutively sampled from a single referral center and identified as whole (non-bisected) biopsy specimens or pre-bisected biopsy specimens. The proportion of inadequate specimens was calculated for both groups. A total of 3450 specimens were included. The percentage of inadequate specimens was 5.072% (153/3016) for whole (non-bisected) specimens and 5.299% for pre-bisected specimens. This difference was not significant (chi square, p = 0.84). The study was sufficiently powered to detect a relative risk of 1.685. Pre-bisection of a single skin biopsy does not significantly increase the risk of a technically inadequate specimen for direct immunofluorescence testing. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Quantitative Assessment of Free Flap Viability with CEUS Using an Integrated Perfusion Software.

    Science.gov (United States)

    Geis, S; Klein, S; Prantl, L; Dolderer, J; Lamby, P; Jung, E-M

    2015-12-01

    New treatment strategies in oncology and trauma surgery lead to an increasing demand for soft tissue reconstruction with free tissue transfer. In previous studies, CEUS was proven to detect early flap failure. The aim of this study was to detect and quantify vascular disturbances after free flap transplantation using a fast integrated perfusion software tool. From 2011 to 2013, 33 patients were examined by one experienced radiologist using CEUS after a bolus injection of 1-2.4 ml of SonoVue(®). Flap perfusion was analysed qualitatively regarding contrast defects or delayed wash-in. Additionally, an integrated semi-quantitative analysis using time-intensity curve analysis (TIC) was performed. TIC analysis of the transplant was conducted on a centimetre-by-centimetre basis up to a penetration depth of 4 cm. The 2 perfusion parameters "Time to PEAK" and "Area under the Curve" were compared in patients without complications vs. patients with minor complications or complete flap loss to figure out significant differences. TtoPk is given in seconds (s) and Area is given in relative units (rU) Results: A regular postoperative process was observed in 26 (79%) patients. In contrast, 5 (15%) patients with partial superficial flap necrosis, 1 patient (3%) with complete flap loss and 1 patient (3%) with haematoma were observed. TtoPk revealed no significant differences, whereas Area revealed significantly lower perfusion values in the corresponding areas in patients with complications. The critical threshold for sufficient flap perfusion was set below 150 rU. In conclusion, CEUS is a mobile and cost-effective opportunity to quantify tissue perfusion and can even be used almost without any restrictions in multi-morbid patients with renal and hepatic failure. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Effect of transarterial pulsed perfusion with heated saline on tumor vascular permeability in a rabbit VX2 liver tumor model

    International Nuclear Information System (INIS)

    Cao Wei; Li Jinghua; Feng Dayun; Wan Yi; Liu Yufeng; Yang Qingfeng; Cheng Jianwei; Zhao Siyuan; Zhang Hongxin

    2012-01-01

    Purpose: To evaluate the effect of transarterial pulsed perfusion with 60 °C saline on vascular permeability of tumor tissue, as well as its hepatic and renal toxicity, in a rabbit VX2 liver model. Materials and methods: VX2 carcinomas were grown in rabbit livers, forty male New Zealand white tumor-bearing rabbits were randomly divided into four groups, followed by transarterial perfusion with 37 °C saline 60 ml (n = 10) (control 1 group), transarterial pulsed perfusion with 37 °C saline 60 ml (n = 10) (control 2 group), transarterial continuous perfusion with 60 °C saline 60 ml (n = 10) (TCP group), transarterial pulsed perfusion with 60 °C saline 60 ml (n = 10) (TPP group), the duration of time for tumor tissues in the range 43–45 °C of the treated groups was measured with needle thermometer during perfusion. Vascular permeability was assessed using the extravasation of Evans blue (EB) dye in the tumor or normal liver tissues of the four groups separately, the tumor or normal liver tissues of the four groups were estimated by histopathologic examination, and hepatic and renal toxicity was evaluated by means of blood biochemical analysis. The vascular endothelial cells in the tumor were observed by transmission electron microscopy (TEM). Results: The duration of time for tumor tissues in the range 43–45 °C of TPP group showed significantly longer than that of TCP group (12.3 ± 3.3 min vs. 5.7 ± 2.5 min) (P 0.05), and there was no significant difference in the serum BUN, Cr levels among the four groups at 1, 2, 4, 8, 24 h after perfusion. Observed by hematoxylin and eosin staining, there were no obvious signs of tissue destruction in liver tissue and tumor tissue. TEM indicating the endothelial cell gap was broadened and the endothelial cells’ microvillus was decreased after heated perfusion. Conclusions: The vascular permeability of the rabbit VX2 tumor was significantly increased after transarterial pulsed perfusion with 60 °C saline without

  2. Micro-lightguide spectrophotometry for tissue perfusion in ischemic limbs

    DEFF Research Database (Denmark)

    Jørgensen, Lise Pyndt; Schroeder, Torben V

    2012-01-01

    To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure.......To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure....

  3. Management of cardiogenic shock: focus on tissue perfusion

    NARCIS (Netherlands)

    den Uil, Corstiaan A.; Lagrand, Wim K.; Valk, Suzanne D. A.; Spronk, Peter E.; Simoons, Maarten L.

    2009-01-01

    Cardiogenic shock (CS) may result from ischemic heart disease, cardiomyopathy, valvular heart disease, inflammation, myocardial contusion, and cardiac surgery. CS is the leading cause of in-hospital death in patients with acute myocardial infarction. Although early revascularization strategies have

  4. Three-dimensional fabrication of thick and densely populated soft constructs with complex and actively perfused channel network

    DEFF Research Database (Denmark)

    Pimentel, C Rodrigo; Ko, Suk Kyu; Caviglia, Claudia

    2017-01-01

    One of the fundamental steps needed to design functional tissues and, ultimately organs is the ability to fabricate thick and densely populated tissue constructs with controlled vasculature and microenvironment. To date, bioprinting methods have been employed to manufacture tissue constructs...... with open vasculature in a square-lattice geometry, where the majority lacks the ability to be directly perfused. Moreover, it appears to be difficult to fabricate vascular tissue constructs targeting the stiffness soft tissues such as the liver. Here we present a method for the fabrication of thick (e.g. 1...... cm) and densely populated (e.g. 10 million cells·mL-1) tissue constructs with a three-dimensional (3D) four arm branch network and stiffness in the range of soft tissues (1-10 kPa), which can be directly perfused on a fluidic platform for long time periods (> 14 days). Specifically, we co-print a 3D...

  5. Intrinsic regulation of blood flow in adipose tissue

    DEFF Research Database (Denmark)

    Henriksen, O; Nielsen, Steen Levin; Paaske, W

    1976-01-01

    Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated...... subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue...... is more susceptible to surgical exposure of the tissue. During elevation of arterial perfusion pressure blood flow in the isolated tissue showed a transient increase and then almost returned to the level during normotension, indicating an elevated vascular resistance. Raising of venous pressure elicited...

  6. Intravascular perfusion of carbon black ink allows reliable visualization of cerebral vessels.

    Science.gov (United States)

    Hasan, Mohammad R; Herz, Josephine; Hermann, Dirk M; Doeppner, Thorsten R

    2013-01-04

    The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes (i.e. carmine red, India ink) or latex with or without carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen. Maeda et al. have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries.

  7. Brief ex vivo perfusion with heparinized and/or citrated whole blood enhances tolerance of free muscle flaps to prolonged ischemia.

    Science.gov (United States)

    Fowler, J D; Li, X; Cooley, B C

    1999-01-01

    This study investigated the use of heparinized and/or citrated whole blood as a perfusate for enhancing muscle tolerance to warm ischemia. Unilateral cutaneous trunci muscle flaps were harvested from Sprague-Dawley rats and stored for 10 hr at 22-24 degrees C prior to transplantation to the groin. One group served as a non-perfused control. In three experimental groups, the flaps were hand-perfused ex vivo with 1.0 ml of heparinized, citrated, or heparinized and citrated autogenous whole blood at physiological pressures. Perfusion was administered over a 10-min period 5 hr into the ischemic period. Flaps were revascularized on the femoral vessels and then harvested 48 hr following revascularization. Tissue injury was assessed by calculation of flap weight change (indicator of tissue edema), histochemical evaluation of muscle dehydrogenase activity (nitroblue tetrazolium assay), and light microscopy. All perfused groups had significantly higher muscle dehydrogenase activity compared with non-perfused controls (P flap edema was seen in the combined heparin-citrate perfusion of flaps compared with nonperfused controls (P flaps. We conclude that mid-ischemic perfusion with heparinized and/or citrated blood limits the deleterious effects of extended warm ischemia.

  8. Ultrasound imaging of breast tumor perfusion and neovascular morphology.

    Science.gov (United States)

    Hoyt, Kenneth; Umphrey, Heidi; Lockhart, Mark; Robbin, Michelle; Forero-Torres, Andres

    2015-09-01

    A novel image processing strategy is detailed for simultaneous measurement of tumor perfusion and neovascular morphology parameters from a sequence of dynamic contrast-enhanced ultrasound (DCE-US) images. After normalization and tumor segmentation, a global time-intensity curve describing contrast agent flow was analyzed to derive surrogate measures of tumor perfusion (i.e., peak intensity, time-to-peak intensity, area under the curve, wash-in rate, wash-out rate). A maximum intensity image was generated from these same segmented image sequences, and each vascular component was skeletonized via a thinning algorithm. This skeletonized data set and collection of vessel segments were then investigated to extract parameters related to the neovascular network and physical architecture (i.e., vessel-to-tissue ratio, number of bifurcations, vessel count, average vessel length and tortuosity). An efficient computation of local perfusion parameters was also introduced and operated by averaging time-intensity curve data over each individual neovascular segment. Each skeletonized neovascular segment was then color-coded by these local measures to produce a parametric map detailing spatial properties of tumor perfusion. Longitudinal DCE-US image data sets were collected in six patients diagnosed with invasive breast cancer using a Philips iU22 ultrasound system equipped with a L9-3 transducer and Definity contrast agent. Patients were imaged using US before and after contrast agent dosing at baseline and again at weeks 6, 12, 18 and 24 after treatment started. Preliminary clinical results suggested that breast tumor response to neoadjuvant chemotherapy may be associated with temporal and spatial changes in DCE-US-derived parametric measures of tumor perfusion. Moreover, changes in neovascular morphology parametric measures may also help identify any breast tumor response (or lack thereof) to systemic treatment. Breast cancer management from early detection to therapeutic

  9. Quantification of myocardial perfusion based on signal intensity of flow sensitized MRI

    Science.gov (United States)

    Abeykoon, Sumeda B.

    The quantitative assessment of perfusion is important for early recognition of a variety of heart diseases, determination of disease severity and their cure. In conventional approach of measuring cardiac perfusion by arterial spin labeling, the relative difference in the apparent T1 relaxation times in response to selective and non-selective inversion of blood entering the region of interest is related to perfusion via a two-compartment tissue model. But accurate determination of T1 in small animal hearts is difficult and prone to errors due to long scan times. The purpose of this study is to develop a fast, robust and simple method to quantitatively assess myocardial perfusion using arterial spin labeling. The proposed method is based on signal intensities (SI) of inversion recovery slice-select, non-select and steady-state images. Especially in this method data are acquired at a single inversion time and at short repetition times. This study began by investigating the accuracy of assessment of perfusion using a two compartment system. First, determination of perfusion by T1 and SI were implemented to a simple, two-compartment phantom model. Mathematical model developed for full spin exchange models (in-vivo experiments) by solving a modified Bloch equation was modified to develop mathematical models (T1 and SI) for a phantom (zero spin exchange). The phantom result at different flow rates shows remarkable evidence of accuracy of the two-compartment model and SI, T1 methods: the SI method has less propagation error and less scan time. Next, twelve healthy C57BL/6 mice were scanned for quantitative perfusion assessment and three of them were repeatedly scanned at three different time points for a reproducibility test. The myocardial perfusion of healthy mice obtained by the SI-method, 5.7+/-1.6 ml/g/min, was similar (p=0.38) to that obtained by the conventional T1 method, 5.6+/- 2.3 ml/g/min. The reproducibility of the SI method shows acceptable results: the

  10. Visual and SPM analysis of regional cerebral perfusion with Tc-99m ECD brain SPECT in patients with developmental language disorder

    International Nuclear Information System (INIS)

    Yoon, Joon Kee; Lee, Myung Hoon; Joh, Chul Woo; Yoon, Seok Nam; Oh, Eun Young

    2003-01-01

    Developmental language disorder (DLD) refers to inadequate language acquisition at the expected age in children with otherwise normal development. However, language delay can be observed in patients with other developmental disoder (ODD). We, therefore, evaluated regional cerebral perfusion pattern in patients with DLD and ODD by means of visual and SPM analysis. Twelve patients, who underwent Tc-99m ECD brain SPECT within 3 weeks of their first visit, were included in the study. Psychological and language tests classified the patients into 2 groups ; 6 with DLD (3-7 yr, 5 male and I female) and 6 with ODD (2-6 yr, 6 male). Visual analysis for regional cerebral perfusion was done in each patient. SPM with 7 controls (age=7) was performed to evaluate difference between 2 groups using t-test. P value of less than 0.005 was considered to be significant. All patients had significant language delay for their age (9 month 3.5 yr). Among 6 patients with ODD, 4 had pervasive developmental disorder, 1 mental retardation and 1 attachment disorder. Visual analysis revealed significant perfusion decrease in only 1 patient with DLD and 2 with ODD ; the regions were left parieto-temporal cortex, both frontal and cerebellar cortices, and right temporal cortex respectively. Nine of 12 patients showed normal perfusion. SPM demonstrated perfusion decrease in left inferior frontal cortex and left superior parietal cortex (Wernicke's area) in patients with DLD, while, in patients with ODD, perfusion decrease was mostly located in the right hemisphere (lateral frontoorbital gyrus, occipitotemporal gyrus, cuneus and cerebellum). Corpus callosum showed no significant perfusion abnormality in both groups. Regional cerebral perfusion of patients with DLD, which was mainly located in the speech area, is quite different from that of ODD-patients with language delay. While SPM successfully revealed this difference in perfusion pattern, visual analysis had limited value

  11. Delta-projection imaging on contrast-enhanced ultrasound to quantify tumor microvasculature and perfusion.

    Science.gov (United States)

    Sehgal, Chandra M; Cary, Theodore W; Arger, Peter H; Wood, Andrew K W

    2009-01-01

    The aim of this study was to assess the Delta-projection image processing technique for visualizing tumor microvessels and for quantifying the area of tissue perfused by them on contrast-enhanced ultrasound images. The Delta-projection algorithm was implemented to quantify perfusion by tracking the running maximum of the difference (Delta) between the contrast-enhanced ultrasound image sequence and a baseline image. Twenty-five mice with subcutaneous K1735 melanomas were first imaged with contrast-enhanced grayscale and then with minimum-exposure contrast-enhanced power Doppler (minexCPD) ultrasound. Delta-projection images were reconstructed from the grayscale images and then used to evaluate the evolution of tumor vascularity during the course of contrast enhancement. The extent of vascularity (ratio of the perfused area to the tumor area) for each tumor was determined quantitatively from Delta-projection images and compared to the extent of vascularity determined from contrast-enhanced power Doppler images. Delta-projection and minexCPD measurements were compared using linear regression analysis. Delta-projection was successfully performed in all 25 cases. The technique allowed the dynamic visualization of individual blood vessels as they filled in real time. Individual tumor blood vessels were distinctly visible during early image enhancement. Later, as an increasing number of blood vessels were filled with the contrast agent, clusters of vessels appeared as regions of perfusion, and the identification of individual vessels became difficult. Comparisons were made between the perfused area of tumors in Delta-projections and in minexCPD images. The Delta-projection perfusion measurements were correlated linearly with minexCPD. Delta-projection visualized tumor vessels and enabled the quantitative assessment of the tumor area perfused by the contrast agent.

  12. Cytokine filtration modulates pulmonary metabolism and edema formation during ex vivo lung perfusion.

    Science.gov (United States)

    Iskender, Ilker; Cosgun, Tugba; Arni, Stephan; Trinkwitz, Michael; Fehlings, Stefan; Yamada, Yoshito; Cesarovic, Nikola; Yu, Keke; Frauenfelder, Thomas; Jungraithmayr, Wolfgang; Weder, Walter; Inci, Ilhan

    2017-05-20

    Ex vivo lung perfusion (EVLP) has improved the process of donor lung management. Cytokine accumulation during EVLP has been shown to correlate with worse outcome after lung transplantation. Our objective in this study was to test the safety and efficacy of cytokine filtration during EVLP in a large animal model. Pig donor lungs were preserved for 24 hours at 4°C, followed by 12 hours of EVLP, according to the Toronto protocol. The perfusate was continuously run through an absorbent device (CytoSorb) via a veno-venous shunt from the reservoir in the filter group. EVLP was performed according to the standard protocol in the control group (n = 5 each). EVLP physiology, lung X-ray, perfusate biochemistry, inflammatory response and microscopic injury were assessed. Cytokine filtration significantly improved airway pressure and dynamic compliance during the 12-hour perfusion period. Lung X-rays acquired at the end of perfusion showed increased consolidation in the control group. Electrolyte imbalance, determined by increased hydrogen, potassium and calcium ion concentrations in the perfusate, was markedly worsened in the control group. Glucose consumption and lactate production were markedly reduced, along with the lactate/pyruvate ratio in the filter group. Cytokine expression profile, tissue myeloperoxidase activity and microscopic lung injury were significantly reduced in the filter group. Continuous perfusate filtration through sorbent beads is effective and safe during prolonged EVLP. Cytokine removal decreased the development of pulmonary edema and electrolyte imbalance through the suppression of anaerobic glycolysis and neutrophil activation in this setting. Further studies are needed to test the beneficial effect of cytokine filtration on post-transplant lung function. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  13. Regional heterogeneity of myocardial perfusion in healthy human myocardium: assessment with magnetic resonance perfusion imaging.

    Science.gov (United States)

    Muehling, Olaf M; Jerosch-Herold, Michael; Panse, Prasad; Zenovich, Andrey; Wilson, Betsy V; Wilson, Robert F; Wilke, Norbert

    2004-01-01

    The knowledge of myocardial perfusion in healthy volunteers is fundamental for evaluation of patients with ischemic heart disease. The study was conducted to determine range, regional variability, and transmural gradient of myocardial perfusion in normal volunteers with Magnetic Resonance Perfusion Imaging (MRPI). Perfusion was assessed in 17 healthy volunteers (age: 20-47 yr, 11 males) at rest and adenosine-induced hyperemia using a 1.5 T MR scanner. Perfusion was quantified (mL/g/min) for the transmural myocardium and separately for the endo- and epimyocardium in the anterior, lateral, posterior, and septal left ventricular wall using the Fermi model for constrained deconvolution. Regional variabilities for resting, hyperemic perfusion, and perfusion reserve were 22 +/- 8%, 21 +/- 10%, and 35 +/- 18%. Mean resting, hyperemic perfusion, and perfusion reserve were 1.1 +/- 0.4 mL/g/min, 4.2 +/- 1.1 mL/g/min, and 4.1 +/- 1.4. Perfusion in the septum was higher at rest (1.3 +/- 0.3 mL/g/min vs. 1.0 +/- 0.3 mL/g/min, p < 0.05) and lower during hyperemia (3.6 +/- 0.8 mL/g/min vs. 4.5 +/- 1.1 mL/g/min, p < 0.03), resulting in a reduced perfusion reserve (PR) (3.2 +/- 0.9 vs. 4.5 +/- 1.4, p < 0.01) in the septum vs. the combined anterior, lateral, and posterior segments. Resting (0.9 +/- 0.3 mL/g/min vs. 1.4 +/- 0.5 mL/g/min, p < 0.01), but not hyperemic perfusion, was lower in the epi- vs. endomyocardium, resulting in a higher epimyocardial PR (4.8 +/- 1.8 vs. 3.5 +/- 1.4, p < 0.01) in all regions but the septum, where endo- and epimyocardial perfusion and perfusion reserve were not different. A considerable regional variability of myocardial perfusion was confirmed with MRPI. The exceptional anatomical position of the septum is reflected by the lack of a perfusion gradient, which was demonstrated in all other regions but the septum.

  14. Increased brainstem perfusion, but no blood-brain barrier disruption, during attacks of migraine with aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal M; Christensen, Casper E

    2017-01-01

    symptoms are related to the headache phase of migraine. Animal studies suggest that cortical spreading depression, the likely mechanism of migraine aura, causes disruption of the blood-brain barrier and noxious stimulation of trigeminal afferents leading to activation of brainstem nuclei and triggering...... of migraine headache. We used the sensitive and validated technique of dynamic contrast-enhanced high-field magnetic resonance imaging to simultaneously investigate blood-brain barrier permeability and tissue perfusion in the brainstem (at the level of the lower pons), visual cortex, and brain areas......-free day. The mean time from attack onset to scanning was 7.6 h. We found increased brainstem perfusion bilaterally during migraine with aura attacks. Perfusion also increased in the visual cortex and posterior white matter following migraine aura. We found no increase in blood-brain barrier permeability...

  15. Metabolism of perfused pig intercostal muscles evaluated by 31P-magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Brian Lindegaard; Arendrup, Henrik; Secher, Niels H

    2006-01-01

    This study presents a perfused preparation for evaluation of metabolism in pig intercostal muscle in vitro. Preserved vessels and nerves to an intercostal segment including two adjacent ribs allowed for tissue perfusion and electrical stimulation with measurement of contraction force, oxygen......, as demonstrated in one preliminary experiment. The results demonstrate a stable and functional in vitro preparation of intact perfused intercostal muscles in the pig........ Tonic stimulation of the nerve caused anaerobic energy consumption as PCr and pH decreased, and both variables recovered after the contraction with half-time values of approximately 7 min. Force increased to 0.040 N g(-1) (range, 0.031-0.103 N g(-1)) and it gradually decreased by about 70% during...

  16. Multimodal imaging of cutaneous wound tissue

    Science.gov (United States)

    Zhang, Shiwu; Gnyawali, Surya; Huang, Jiwei; Ren, Wenqi; Gordillo, Gayle; Sen, Chandan K.; Xu, Ronald

    2015-01-01

    Quantitative assessment of wound tissue ischemia, perfusion, and inflammation provides critical information for appropriate detection, staging, and treatment of chronic wounds. However, few methods are available for simultaneous assessment of these tissue parameters in a noninvasive and quantitative fashion. We integrated hyperspectral, laser speckle, and thermographic imaging modalities in a single-experimental setup for multimodal assessment of tissue oxygenation, perfusion, and inflammation characteristics. Algorithms were developed for appropriate coregistration between wound images acquired by different imaging modalities at different times. The multimodal wound imaging system was validated in an occlusion experiment, where oxygenation and perfusion maps of a healthy subject's upper extremity were continuously monitored during a postocclusive reactive hyperemia procedure and compared with standard measurements. The system was also tested in a clinical trial where a wound of three millimeters in diameter was introduced on a healthy subject's lower extremity and the healing process was continuously monitored. Our in vivo experiments demonstrated the clinical feasibility of multimodal cutaneous wound imaging.

  17. Optical techniques for perfusion monitoring of the gastric tube after esophagectomy: a review of technologies and thresholds.

    Science.gov (United States)

    Jansen, S M; de Bruin, D M; van Berge Henegouwen, M I; Strackee, S D; Veelo, D P; van Leeuwen, T G; Gisbertz, S S

    2018-04-26

    Anastomotic leakage is one of the most severe complications after esophageal resection with gastric tube reconstruction. Impaired perfusion of the gastric fundus is seen as the main contributing factor for this complication. Optical modalities show potential in recognizing compromised perfusion in real time, when ischemia is still reversible. This review provides an overview of optical techniques with the aim to evaluate the (1) quantitative measurement of change in perfusion in gastric tube reconstruction and (2) to test which parameters are the most predictive for anastomotic leakage.A Pubmed, MEDLINE, and Embase search was performed and articles on laser Doppler flowmetry (LDF), near-infrared spectroscopy (NIRS), laser speckle contrast imaging (LSCI), fluorescence imaging (FI), sidestream darkfield microscopy (SDF), and optical coherence tomography (OCT) regarding blood flow in gastric tube surgery were reviewed. Two independent reviewers critically appraised articles and extracted the data: Primary outcome was quantitative measure of perfusion change; secondary outcome was successful prediction of necrosis or anastomotic leakage by measured perfusion parameters.Thirty-three articles (including 973 patients and 73 animals) were selected for data extraction, quality assessment, and risk of bias (QUADAS-2). LDF, NIRS, LSCI, and FI were investigated in gastric tube surgery; all had a medium level of evidence. IDEAL stage ranges from 1 to 3. Most articles were found on LDF (n = 12), which is able to measure perfusion in arbitrary perfusion units with a significant lower amount in tissue with necrosis development and on FI (n = 12). With FI blood flow routes could be observed and flow was qualitative evaluated in rapid, slow, or low flow. NIRS uses mucosal oxygen saturation and hemoglobin concentration as perfusion parameters. With LSCI, a decrease of perfusion units is observed toward the gastric fundus intraoperatively. The perfusion units (LDF, LSCI), although

  18. Evaluating optimal superficial limb perfusion at different angles using non-invasive micro-lightguide spectrophotometry.

    Science.gov (United States)

    Darmanin, Geraldine; Jaggard, Matthew; Hettiaratchy, Shehan; Nanchahal, Jagdeep; Jain, Abhilash

    2013-06-01

    It is common practice to elevate the limbs postoperatively to reduce oedema and hence optimise perfusion and facilitate rehabilitation. However, elevation may be counterproductive as it reduces the mean perfusion pressure. There are no clear data on the optimal position of the limbs even in normal subjects. The optimal position of limbs was investigated in 25 healthy subjects using a non-invasive micro-lightguide spectrophotometry system "O2C", which indirectly measures skin and superficial tissue perfusion through blood flow, oxygen saturation and relative haemoglobin concentration. We found a reduction in skin and superficial tissue blood flow of 17% (p=0.0001) on arm elevation (180° shoulder flexion) as compared to heart level and an increase in skin and superficial tissue blood flow of 25% (p=0.02) on forearm elevation of 45°. Lower limb skin and superficial tissue blood flow decreased by 15% (p=0.004) on elevation to 47 cm and by 70% on dependency (p=0.0001) compared to heart level. However, on elevation of the lower limb there was also a 28% reduction in superficial venous pooling (p=0.0001) compared to heart level. In the normal limb, the position for optimal superficial perfusion of the upper limb is with the arm placed at heart level and forearm at 45°. In the lower limb the optimal position for superficial perfusion would be at heart level. However, some degree of elevation may be useful if there is an element of venous congestion. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Ventilation-perfused studies using SPECT

    International Nuclear Information System (INIS)

    Zwijnenburg, A.

    1989-01-01

    A method for the quantitative analysis of ventilation-perfusion SPECT studies is decribed and an effort is made to evaluate its usefullness. The technical details of the emthod are described. In the the transaxial reconstructions of the tomographic studies the contour of the lungs is detected and regional values of lung volume, ventilation, perfusion and ventilation-perfusion ratios are calculated. The method is operator independent. The lung volume calculations from the SPECT studies are validated by comparing them with lung volume measurements using the helium dilution technique. A good correlation (r=0.91) was found between the two volumes. SPECT volume was greater than the volume measured with helium dilution, which was attributed to non-gas-containing structures in the. lungs. The use of ventilation-perfusion ratio SPECT is described to evaluate the effect of ionizing radiation on the lungs in patients treated with mantle field irradiation for Hodgkin's disease. Perfusion changes appear as early as 2 months after the start of irradiation. Ventilation changes appear later and relatively minor. No changes are seen outside the radiation portals. The ventilation-perfusion inequality in pulmonary sarcoidosis is treated. It is suggested that the decrease D LCO in these patients may be partly due to an even distribution of ventilation perfusion ratios. An effort is made to establish the properties of a new tracer used for the assessment of the metabolic function of the pulmonary endothelium. The lung uptake of I-123 IMP mimics the distribution of a perfusion tracer and it is suggested that this tracer may be useful for the early detection of pulmonary vascular damage, even when blood flow is still intact. Some aspects of the use of Kr-81m as a ventilation tracer are discussed as well as the effect of noise on Kr-81m SPECT reconstructions. (author). 146 refs.; 39 figs.; 8 tabs

  20. Vicarious audiovisual learning in perfusion education.

    Science.gov (United States)

    Rath, Thomas E; Holt, David W

    2010-12-01

    Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video.These modules described the setup and operation of the MAQUET ROTAFLOW stand-alone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today's perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p learning module than text learners. Vicarious audiovisual learning modules may be an efficacious, low cost means of delivering perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important role in how we teach perfusion in the future, as simulation technology becomes more prevalent.

  1. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8...

  2. Quantitative lung perfusion mapping at 0.2 T using FAIR True-FISP MRI.

    Science.gov (United States)

    Martirosian, Petros; Boss, Andreas; Fenchel, Michael; Deimling, Michael; Schäfer, Jürgen; Claussen, Claus D; Schick, Fritz

    2006-05-01

    Perfusion measurements in lung tissue using arterial spin labeling (ASL) techniques are hampered by strong microscopic field gradients induced by susceptibility differences between the alveolar air and the lung parenchyma. A true fast imaging with steady precession (True-FISP) sequence was adapted for applications in flow-sensitive alternating inversion recovery (FAIR) lung perfusion imaging at 0.2 Tesla and 1.5 Tesla. Conditions of microscopic static field distribution were assessed in four healthy volunteers at both field strengths using multiecho gradient-echo sequences. The full width at half maximum (FWHM) values of the frequency distribution for 180-277 Hz at 1.5 Tesla were more than threefold higher compared to 39-109 Hz at 0.2 Tesla. The influence of microscopic field inhomogeneities on the True-FISP signal yield was simulated numerically. Conditions allowed for the development of a FAIR True-FISP sequence for lung perfusion measurement at 0.2 Tesla, whereas at 1.5 Tesla microscopic field inhomogeneities appeared too distinct. Perfusion measurements of lung tissue were performed on eight healthy volunteers and two patients at 0.2 Tesla using the optimized FAIR True-FISP sequence. The average perfusion rates in peripheral lung regions in transverse, sagittal, and coronal slices of the left/right lung were 418/400, 398/416, and 370/368 ml/100 g/min, respectively. This work suggests that FAIR True-FISP sequences can be considered appropriate for noninvasive lung perfusion examinations at low field strength. Copyright (c) 2006 Wiley-Liss, Inc.

  3. Effect of nutritional status on oxidative stress in an ex vivo perfused rat liver.

    Science.gov (United States)

    Stadler, Michaela; Nuyens, Vincent; Seidel, Laurence; Albert, Adelin; Boogaerts, Jean G

    2005-11-01

    Normothermic ischemia-reperfusion is a determinant in liver injury occurring during surgical procedures, ischemic state, and multiple organ failure. The preexisting nutritional status of the liver might contribute to the extent of tissue injury and primary nonfunction. The aim of this study was to determine the role of starvation on hepatic ischemia-reperfusion injury in normal rat livers. Rats were randomly divided into two groups: one had free access to food, the other was fasted for 16 h. The portal vein was cannulated, and the liver was removed and perfused in a closed ex vivo system. Two modes of perfusion were applied in each series of rats, fed and fasting. In the ischemia-reperfusion mode, the experiment consisted of perfusion for 15 min, warm ischemia for 60 min, and reperfusion during 60 min. In the nonischemia mode, perfusion was maintained during the 135-min study period. Five rats were included in each experimental condition, yielding a total of 20 rats. Liver enzymes, potassium, glucose, lactate, free radicals, i.e., dienes and trienes, and cytochrome c were analyzed in perfusate samples. The proportion of glycogen in hepatocytes was determined in tissue biopsies. Transaminases, lactate dehydrogenase, potassium, and free radical concentrations were systematically higher in fasting rats in both conditions, with and without ischemia. Cytochrome c was higher after reperfusion in the fasting rats. Glucose and lactate concentrations were greater in the fed group. The glycogen content decreased in both groups during the experiment but was markedly lower in the fasting rats. In fed rats, liver injury was moderate, whereas hepatocytes integrity was notably impaired both after continuous perfusion and warm ischemia in fasting animals. Reduced glycogen store in hepatocytes may explain reduced tolerance.

  4. Rapid perfusion quantification using Welch-Satterthwaite approximation and analytical spectral filtering

    Science.gov (United States)

    Krishnan, Karthik; Reddy, Kasireddy V.; Ajani, Bhavya; Yalavarthy, Phaneendra K.

    2017-02-01

    CT and MR perfusion weighted imaging (PWI) enable quantification of perfusion parameters in stroke studies. These parameters are calculated from the residual impulse response function (IRF) based on a physiological model for tissue perfusion. The standard approach for estimating the IRF is deconvolution using oscillatory-limited singular value decomposition (oSVD) or Frequency Domain Deconvolution (FDD). FDD is widely recognized as the fastest approach currently available for deconvolution of CT Perfusion/MR PWI. In this work, three faster methods are proposed. The first is a direct (model based) crude approximation to the final perfusion quantities (Blood flow, Blood volume, Mean Transit Time and Delay) using the Welch-Satterthwaite approximation for gamma fitted concentration time curves (CTC). The second method is a fast accurate deconvolution method, we call Analytical Fourier Filtering (AFF). The third is another fast accurate deconvolution technique using Showalter's method, we call Analytical Showalter's Spectral Filtering (ASSF). Through systematic evaluation on phantom and clinical data, the proposed methods are shown to be computationally more than twice as fast as FDD. The two deconvolution based methods, AFF and ASSF, are also shown to be quantitatively accurate compared to FDD and oSVD.

  5. VERTICAL GRADIENTS IN REGIONAL LUNG DENSITY AND PERFUSION IN THE SUPINE HUMAN LUNG: THE SLINKY® EFFECT

    Science.gov (United States)

    Hopkins, Susan R.; Henderson, A. Cortney; Levin, David L.; Yamada, Kei; Arai, Tatsuya; Buxton, Richard B.; Prisk., G. Kim

    2008-01-01

    In-vivo radioactive tracer and microsphere studies have differing conclusions as to the magnitude of the gravitational effect on the distribution of pulmonary blood flow. We hypothesized that some of the apparent vertical perfusion gradient in-vivo is due to compression of dependent lung increasing local lung density and therefore perfusion/volume. To test this, 6 normal subjects underwent functional MRI with arterial spin labeling during a breath-hold at functional residual capacity, and perfusion quantified in non-overlapping 15mm sagittal slices covering most of the right lung. Lung proton density was measured in the same slices using a short echo 2D-FLASH sequence. Mean perfusion was 1.7 ± 0.6 ml/min/cm3 and was related to vertical height above the dependent lung (slope = −3%/cm, p Slinky®, a deformable spring distorting under its own weight. The greater density of lung tissue in the dependent regions of the lung is analogous to a greater number of coils in the dependent portion of the vertically oriented spring. This implies that measurements of perfusion in-vivo will be influenced by density distributions and will differ from excised lungs where density gradients are reduced by processing. PMID:17395757

  6. Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect.

    Science.gov (United States)

    Hopkins, Susan R; Henderson, A Cortney; Levin, David L; Yamada, Kei; Arai, Tatsuya; Buxton, Richard B; Prisk, G Kim

    2007-07-01

    In vivo radioactive tracer and microsphere studies have differing conclusions as to the magnitude of the gravitational effect on the distribution of pulmonary blood flow. We hypothesized that some of the apparent vertical perfusion gradient in vivo is due to compression of dependent lung increasing local lung density and therefore perfusion/volume. To test this, six normal subjects underwent functional magnetic resonance imaging with arterial spin labeling during breath holding at functional residual capacity, and perfusion quantified in nonoverlapping 15 mm sagittal slices covering most of the right lung. Lung proton density was measured in the same slices using a short echo 2D-Fast Low-Angle SHot (FLASH) sequence. Mean perfusion was 1.7 +/- 0.6 ml x min(-1) x cm(-3) and was related to vertical height above the dependent lung (slope = -3%/cm, P Slinky (Slinky is a registered trademark of Poof-Slinky Incorporated), a deformable spring distorting under its own weight. The greater density of lung tissue in the dependent regions of the lung is analogous to a greater number of coils in the dependent portion of the vertically oriented spring. This implies that measurements of perfusion in vivo will be influenced by density distributions and will differ from excised lungs where density gradients are reduced by processing.

  7. A 4D CT digital phantom of an individual human brain for perfusion analysis

    Science.gov (United States)

    Brune, Christoph; van Ginneken, Bram; Prokop, Mathias

    2016-01-01

    Brain perfusion is of key importance to assess brain function. Modern CT scanners can acquire perfusion maps of the cerebral parenchyma in vivo at submillimeter resolution. These perfusion maps give insights into the hemodynamics of the cerebral parenchyma and are critical for example for treatment decisions in acute stroke. However, the relations between acquisition parameters, tissue attenuation curves, and perfusion values are still poorly understood and cannot be unraveled by studies involving humans because of ethical concerns. We present a 4D CT digital phantom specific for an individual human brain to analyze these relations in a bottom-up fashion. Validation of the signal and noise components was based on 1,000 phantom simulations of 20 patient imaging data. This framework was applied to quantitatively assess the relation between radiation dose and perfusion values, and to quantify the signal-to-noise ratios of penumbra regions with decreasing sizes in white and gray matter. This is the first 4D CT digital phantom that enables to address clinical questions without having to expose the patient to additional radiation dose. PMID:27917312

  8. CT perfusion study of neck lymph nodes

    International Nuclear Information System (INIS)

    Zhong Jin; Liu Jun; Hua Rui; Qiao Hui; Gong Yi

    2011-01-01

    Objective: To study the CT perfusion features of various lymph nodes in the neck. Methods: Dynamic perfusion CT scanning was performed in 83 neck lymph nodes proved by pathology, including tuberculosis lymph nodes, lymphoma and metastatic lymph nodes. The shapes, blood flow modes, and perfusion parameters of these lymph nodes were compared among 3 groups. Statistical analysis of L/T and CT perfusion parameters was performed by one-way ANOVA and LSD test. Results: The values of MTT of tuberculosis lymph nodes, lymphoma and metastatic lymph nodes were (28.13±5.08), (31.08±5.82), and (11.24±5.31) s, respectively. The MTT of metastatic lymph nodes was statistically lower than that of tuberculosis lymph nodes and lymphoma (P -1 · 100 g -1 , respectively. The values of BV were (24.68±2.84), (25.30±3.16), and (25.15± 8.81) ml·100 g -1 respectively. The values of TTP were (40.90±8.85), (40.67±6.45), and (40.98±6.62) s, respectively. There were no significant differences in L/T, BF, BV and TTP among tuberculosis lymph nodes, lymphoma and metastatic lymph nodes (P>0.05). Conclusion: CT perfusion, especially combination functional imaging with perfusion images may be helpful in judging the nature of neck lymph nodes. (authors)

  9. Multiple-indicator dilution technique for characterization of normal and retrograde flow in once-through rat liver perfusions

    International Nuclear Information System (INIS)

    St-Pierre, M.V.; Schwab, A.J.; Goresky, C.A.; Lee, W.F.; Pang, K.S.

    1989-01-01

    The technique of normal and retrograde rat liver perfusion has been widely used to probe zonal differences in drug-metabolizing activities. The validity of this approach mandates the same tissue spaces being accessed by substrates during both normal and retrograde perfusions. Using the multiple-indicator dilution technique, we presently examine the extent to which retrograde perfusion alters the spaces accessible to noneliminated references. A bolus dose of 51Cr-labeled red blood cells, 125I-albumin, 14C-sucrose and 3H2O was injected into the portal (normal) or hepatic (retrograde) vein of rat livers perfused at 10 ml per min per liver. The outflow perfusate was serially collected over 220 sec to characterize the transit times and the distribution spaces of the labels. During retrograde perfusion, red blood cells, albumin and sucrose profiles peaked later and lower than during normal perfusion, whereas the water curves were similar. The transit times of red blood cells, albumin and sucrose were longer (p less than 0.005), whereas those for water did not change. Consequently, retrograde flow resulted in significantly larger sinusoidal blood volumes (45%), albumin Disse space (42%) and sucrose Disse space (25%) than during normal flow, whereas the distribution spaces for total and intracellular water remained unaltered. The distension of the vascular tree was confirmed by electron microscopy, by which occasional isolated foci of widened intercellular recesses and spaces of Disse were observed. Cellular ultrastructure was otherwise unchanged, and there was no difference found between normal and retrograde perfusion for bile flow rates, AST release, perfusion pressure, oxygen consumption and metabolic removal of ethanol, a substrate with flow-limited distribution, which equilibrates rapidly with cell water (hepatic extraction ratios were virtually identical: normal vs. retrograde, 0.50 vs. 0.48 at 6 to 7.4 mM input concentration)

  10. Mesenchymal Stem/Stromal Cells from Discarded Neonatal Sternal Tissue: In Vitro Characterization and Angiogenic Properties

    Directory of Open Access Journals (Sweden)

    Shuyun Wang

    2016-01-01

    Full Text Available Autologous and nonautologous bone marrow mesenchymal stem/stromal cells (MSCs are being evaluated as proangiogenic agents for ischemic and vascular disease in adults but not in children. A significant number of newborns and infants with critical congenital heart disease who undergo cardiac surgery already have or are at risk of developing conditions related to inadequate tissue perfusion. During neonatal cardiac surgery, a small amount of sternal tissue is usually discarded. Here we demonstrate that MSCs can be isolated from human neonatal sternal tissue using a nonenzymatic explant culture method. Neonatal sternal bone MSCs (sbMSCs were clonogenic, had a surface marker expression profile that was characteristic of bone marrow MSCs, were multipotent, and expressed pluripotency-related genes at low levels. Neonatal sbMSCs also demonstrated in vitro proangiogenic properties. Sternal bone MSCs cooperated with human umbilical vein endothelial cells (HUVECs to form 3D networks and tubes in vitro. Conditioned media from sbMSCs cultured in hypoxia also promoted HUVEC survival and migration. Given the neonatal source, ease of isolation, and proangiogenic properties, sbMSCs may have relevance to therapeutic applications.

  11. Technical aspects of MR perfusion

    International Nuclear Information System (INIS)

    Sourbron, Steven

    2010-01-01

    The most common methods for measuring perfusion with MRI are arterial spin labelling (ASL), dynamic susceptibility contrast (DSC-MRI), and T 1 -weighted dynamic contrast enhancement (DCE-MRI). This review focuses on the latter approach, which is by far the most common in the body and produces measures of capillary permeability as well. The aim is to present a concise but complete overview of the technical issues involved in DCE-MRI data acquisition and analysis. For details the reader is referred to the references. The presentation of the topic is essentially generic and focuses on technical aspects that are common to all DCE-MRI measurements. For organ-specific problems and illustrations, we refer to the other papers in this issue. In Section 1 'Theory' the basic quantities are defined, and the physical mechanisms are presented that provide a relation between the hemodynamic parameters and the DCE-MRI signal. Section 2 'Data acquisition' discusses the issues involved in the design of an optimal measurement protocol. Section 3 'Data analysis' summarizes the steps that need to be taken to determine the hemodynamic parameters from the measured data.

  12. Normal myocardial perfusion imaging in the presence of significant coronary artery stenosis

    International Nuclear Information System (INIS)

    Tian Yueqin; He Zuoxiang; Fang Wei; Yang Minfu; Shen Rui

    2007-01-01

    Objective: The aim of this study was to investigate the factors which might result in normal myocardial perfusion imaging in the presence of significant coronary artery stenosis. Methods: One hundred and thirty-three patients [mean age of (59±10) years, 98 men, 35 women] who underwent coronary angiography and myocardial perfusion SPECT were retrospectively analyzed. Results: Forty-six (35%) patients performed adequate bicycle exercise testing and achieved more than 85% of their predicted maximal heart rates; while 87 (65%) patients did not. Eighty-four (63%) patients had single coronary stenosis, 31(23%) two-vessel and 17(13%) three-vessel diseases. The difference in stenosis severity among the vessels in 13 (76%) cases with three-vessel diseases was not more than 20%. There were totally 202 coronary artery stenosis: 93 (46%) in left anterior descending coronary artery (LAD), 52 (26%) left circumflex coronary artery (LCX), 52(26% ) right coronary artery (RCA) and 5 (2%) left main coronary artery (LM) disease. Eighty-six(43%) vessels had 50%-70% stenosis, 100 (49%) >70%-90% and 16(8% )more than 90%. Conclusion: Normal myocardial perfusion imaging with significant coronary artery stenosis can probably due to inadequate exercise, single vessel disease and mild to moderate stenotic lesion. (authors)

  13. Abnormal perfusion on myocardial perfusion SPECT in patients with WPW syndrome: clinical implications

    International Nuclear Information System (INIS)

    Kang, Do Young; Cha, Kwang Soo; Kim, Moo Hyun; Kim, Young Dae; Kim, Duk Kyu

    2001-01-01

    Myocardial perfusion is altered significantly in patients with rhythm disturbances such as CLBBB and right ventricular pacing rhythm. Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on SPECT in patients with WPW syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial SPECT with or without coronary angiography were performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECG or electrophysiologic study. Small to large extent (11.0 8.5%, range: 0 35%) and mild to moderate severity (-71.8 42.7%, range: -217 0%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patient with right free wall AP showed normal. Other defect locations were as follows. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. It was not specifically correlated with location of accessory pathway, but most of all patients were abnormal perfusion pattern. Therefore myocardial perfusion SPECT was interpreted carefully in patients with WPW syndrome

  14. The role of interleukin-1β as a predictive biomarker and potential therapeutic target during clinical ex vivo lung perfusion.

    Science.gov (United States)

    Andreasson, Anders S I; Borthwick, Lee A; Gillespie, Colin; Jiwa, Kasim; Scott, Jonathan; Henderson, Paul; Mayes, Jonny; Romano, Rosalba; Roman, Marius; Ali, Simi; Fildes, James E; Marczin, Nandor; Dark, John H; Fisher, Andrew J

    2017-09-01

    Extended criteria donor lungs deemed unsuitable for immediate transplantation can be reconditioned using ex vivo lung perfusion (EVLP). Objective identification of which donor lungs can be successfully reconditioned and will function well post-operatively has not been established. This study assessed the predictive value of markers of inflammation and tissue injury in donor lungs undergoing EVLP as part of the DEVELOP-UK study. Longitudinal samples of perfusate, bronchoalveolar lavage, and tissue from 42 human donor lungs undergoing clinical EVLP assessments were analyzed for markers of inflammation and tissue injury. Levels were compared according to EVLP success and post-transplant outcomes. Neutrophil adhesion to human pulmonary microvascular endothelial cells (HPMECs) conditioned with perfusates from EVLP assessments was investigated on a microfluidic platform. The most effective markers to differentiate between in-hospital survival and non-survival post-transplant were perfusate interleukin (IL)-1β (area under the curve = 1.00, p = 0.002) and tumor necrosis factor-α (area under the curve = 0.95, p = 0.006) after 30 minutes of EVLP. IL-1β levels in perfusate correlated with upregulation of intracellular adhesion molecule-1 in donor lung vasculature (R 2 = 0.68, p < 0.001) and to a lesser degree upregulation of intracellular adhesion molecule-1 (R 2 = 0.30, p = 0.001) and E-selectin (R 2 = 0.29, p = 0.001) in conditioned HPMECs and neutrophil adhesion to conditioned HPMECs (R 2 = 0.33, p < 0.001). Neutralization of IL-1β in perfusate effectively inhibited neutrophil adhesion to conditioned HPMECs (91% reduction, p = 0.002). Donor lungs develop a detectable and discriminatory pro-inflammatory signature in perfusate during EVLP. Blocking the IL-1β pathway during EVLP may reduce endothelial activation and subsequent neutrophil adhesion on reperfusion; this requires further investigation in vivo. Copyright © 2017 The Authors. Published by Elsevier Inc. All

  15. Effect of methotrexate on perfusion and nitrogen-13 glutamate uptake in the Walker-256 carcinosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, W.H.; Panzer, M.; Helus, F.; Layer, K.; Sinn, H.J.; Ostertag, H.

    1988-02-01

    The tissue uptake of (/sup 13/N)glutamate (glu) was related to that of (/sup 11/C)butanol (but), a highly diffusible perfusion tracer. In 25 rats bearing Walker-256 carcinomas tumor-to-muscle glu uptake averaged 6.34 +/- 2.84 (s.d.) prior to interventions and the respective uptake of but was 6.79 +/- 3.08 (y = 0.03 + 0.94x). One hour after selective intraarterial administration of methotrexate (mtx), glu uptake fell by 47%, whereas blood flow remained within the pretreatment range (N = 9). Four hours after mtx, perfusion was reduced by approximately 40%, and 2 days later both perfusion and glu uptake reached extremely low levels. No significant difference in the effect of 10 and 50 mg/kg mtx was observed. Regional tissue mtx uptake estimations using /sup 77/Br-labeled bromomethotrexate did not reveal any significant uptake in muscle. The relationship between tumor-to-muscle uptake of glu and but (/sup 13/N//sup 11/C-index) was 0.94 +/- 0.015 (s.e.m., N = 25) before intervention. After methotrexate (1 hr, 4 hr, and 2 days) this index was 0.58 +/- 0.06 (N = 9), and 0.85 +/- 0.04 (N = 11) and 1.03 +/- 0.05 (N = 5), respectively. These values demonstrate an early mtx-induced uncoupling of glu uptake with respect to perfusion.

  16. Effects of shear forces and pressure on blood vessel function and metabolism in a perfusion bioreactor.

    Science.gov (United States)

    Hoenicka, Markus; Wiedemann, Ludwig; Puehler, Thomas; Hirt, Stephan; Birnbaum, Dietrich E; Schmid, Christof

    2010-12-01

    Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2. Group 3 vessels were additionally strained with luminal pressure. Groups 1-d through 3-d were similar except that BSV were endothelium-denuded before perfusion. Groups 1-a through 3-a used native vessels at elevated flow rates. Group 3 vessels responded significantly better to noradrenaline on day 4, whereas denuded vessels showed attenuated responses (p vessels. pO₂ gradients across the vessels were independent of time and significantly higher in group 2 (p vessels of groups 3, 1-d, and 3-d which released more lactate than glucose could supply (p vessels as well as all vessels perfused with elevated flow rates showed a loss of endothelial cells after 4 days, whereas group 2 and 3 vessels retained most of the endothelium. These data suggest that vessel metabolism was not limited by oxygen supply. Shear forces did not affect glucose metabolism but increased oxygen consumption and endothelial cell survival. Luminal pressure caused the utilization of energy sources other than glucose, as long as the endothelium was intact. Therefore, vessel metabolism needs to be monitored during tissue engineering procedures which challenge the constructs with mechanical stimuli.

  17. Assessing chronic wound perfusion in the lower extremity: current and emerging approaches

    Directory of Open Access Journals (Sweden)

    Woo KY

    2015-10-01

    Full Text Available Kevin Y Woo,1 Timothy M Brandys,2 Joseph A Marin1 1School of Nursing, Faculty of Health Sciences, Queen's University, Kingston, 2Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada Abstract: Current evidence suggests that vascular and wound bed perfusion assessment should be integral to the care of people with chronic wounds in the lower extremities. Peripheral artery diseases can be insidious, with many affected individuals unaware of circulation issues and failing to seek medical help until they develop foot ulcers, gangrene, and other related complications. Measuring tissue perfusion is a useful diagnostic marker for chronic wounds and may help determine a wound's potential for healing. A complete patient history and physical examination is imperative to help determine the correct diagnosis of lower extremity ulcers. This article aims to discuss current and emerging wound perfusion assessment techniques, including ankle–brachial index, toe–brachial index, transcutaneous oxygen pressure, near-infrared spectroscopy, digital subtraction angiography, magnetic resonance angiography, computed tomographic angiography, and indocyanine green angiography. Keywords: tissue perfusion, peripheral arterial disease, oxygen, wound healing

  18. Near infrared spectroscopy for controlling the quality of distal leg perfusion in remote access cardiopulmonary bypass.

    Science.gov (United States)

    Schachner, Thomas; Bonaros, Nikolaos; Bonatti, Johannes; Kolbitsch, Christian

    2008-12-01

    The prevention of leg ischemia is necessary in all patients undergoing femoral artery cannulation for extracorporeal circulation. Near infrared spectroscopy (NIRS) is an established non-invasive method for measuring tissue oxygen saturation. Ten patients underwent robotically assisted endoscopic coronary surgery or ASD repair on the arrested heart using aortic endo-occlusion catheters. They were monitored by transcutaneous NIRS (placed on both lower legs) for quality control of distal leg perfusion during femoral access cardiopulmonary bypass. The baseline NIRS values were 61 (52-80) on the cannulated side versus 70 (53-80) on the contralateral leg (p=n.s.). During clamping of the femoral artery for installation of the remote access perfusion system the tissue oxygen saturation dropped to 38 (18-58) (p=0.001 vs baseline) while it remained stable on the contralateral leg. After successful implantation of the distal leg perfusion the NIRS values normalized to similar amounts on both legs. We conclude that transcutaneous NIRS of the lower legs might be a useful non-invasive tool for monitoring leg perfusion in patients undergoing extracorporeal circulation via the femoral vessels.

  19. Temperature effects on surface pressure-induced changes in rat skin perfusion: implications in pressure ulcer development.

    Science.gov (United States)

    Patel, S; Knapp, C F; Donofrio, J C; Salcido, R

    1999-07-01

    The effect of varying local skin temperature on surface pressure-induced changes in skin perfusion and deformation was determined in hairless fuzzy rats (13.5+/-3 mo, 474+/-25 g). Skin surface pressure was applied by a computer-controlled plunger with corresponding skin deformation measured by a linear variable differential transformer while a laser Doppler flowmeter measured skin perfusion. In Protocol I, skin surface perfusion was measured without heating (control, T=28 degrees C), with heating (T=36 degrees C), for control (probe just touching skin, 3.7 mmHg), and at two different skin surface pressures, 18 mmHg and 73 mmHg. Heating caused perfusion to increase at control and 18 mmHg pressure, but not at 73 mmHg. In Protocol II, skin perfusion was measured with and without heating as in Protocol I, but this time skin surface pressure was increased from 3.7 to 62 mmHg in increments of 3.7 mmHg. For unheated skin, perfusion increased as skin surface pressure increased from 3.7 to 18 mmHg. Further increases in surface pressure caused a decrease in perfusion until zero perfusion was reached for pressures over 55 mmHg. Heating increased skin perfusion for surface pressures from 3.7 to 18 mmHg, but not for pressures greater than 18 mmHg. After the release of surface pressure, the reactive hyperemia peak of perfusion increased with heating. In Protocol III, where skin deformation (creep and relaxation) was measured during the application of 3.7 and 18 mmHg, heating caused the tissue to be stiffer, allowing less deformation. It was found that for surface pressures below 18 mmHg, increasing skin temperature significantly increased skin perfusion and tissue stiffness. The clinical significance of these findings may have relevance in evaluating temperature and pressure effects on skin blood flow and deformation as well as the efficacy of using temperature as a therapeutic modality in the treatment of pressure ulcers.

  20. GPU-accelerated voxelwise hepatic perfusion quantification.

    Science.gov (United States)

    Wang, H; Cao, Y

    2012-09-07

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using compute unified device architecture-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, nonlinear least-squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626 400 voxels in a patient's liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10(-6). The method will be useful for generating liver perfusion images in clinical settings.

  1. GPU-Accelerated Voxelwise Hepatic Perfusion Quantification

    Science.gov (United States)

    Wang, H; Cao, Y

    2012-01-01

    Voxelwise quantification of hepatic perfusion parameters from dynamic contrast enhanced (DCE) imaging greatly contributes to assessment of liver function in response to radiation therapy. However, the efficiency of the estimation of hepatic perfusion parameters voxel-by-voxel in the whole liver using a dual-input single-compartment model requires substantial improvement for routine clinical applications. In this paper, we utilize the parallel computation power of a graphics processing unit (GPU) to accelerate the computation, while maintaining the same accuracy as the conventional method. Using CUDA-GPU, the hepatic perfusion computations over multiple voxels are run across the GPU blocks concurrently but independently. At each voxel, non-linear least squares fitting the time series of the liver DCE data to the compartmental model is distributed to multiple threads in a block, and the computations of different time points are performed simultaneously and synchronically. An efficient fast Fourier transform in a block is also developed for the convolution computation in the model. The GPU computations of the voxel-by-voxel hepatic perfusion images are compared with ones by the CPU using the simulated DCE data and the experimental DCE MR images from patients. The computation speed is improved by 30 times using a NVIDIA Tesla C2050 GPU compared to a 2.67 GHz Intel Xeon CPU processor. To obtain liver perfusion maps with 626400 voxels in a patient’s liver, it takes 0.9 min with the GPU-accelerated voxelwise computation, compared to 110 min with the CPU, while both methods result in perfusion parameters differences less than 10−6. The method will be useful for generating liver perfusion images in clinical settings. PMID:22892645

  2. Inadequate humidification of respiratory gases during mechanical ventilation of the newborn.

    Science.gov (United States)

    Tarnow-Mordi, W O; Sutton, P; Wilkinson, A R

    1986-01-01

    Proximal airway humidity was measured during mechanical ventilation in 14 infants using an electronic hygrometer. Values below recommended minimum humidity of adult inspired gas were recorded on 251 of 396 occasions. Inadequate humidification, largely due to inadequate proximal airway temperature, is commoner than recognised in infants receiving mechanical ventilation. PMID:3740912

  3. Inadequate humidification of respiratory gases during mechanical ventilation of the newborn.

    OpenAIRE

    Tarnow-Mordi, W O; Sutton, P; Wilkinson, A R

    1986-01-01

    Proximal airway humidity was measured during mechanical ventilation in 14 infants using an electronic hygrometer. Values below recommended minimum humidity of adult inspired gas were recorded on 251 of 396 occasions. Inadequate humidification, largely due to inadequate proximal airway temperature, is commoner than recognised in infants receiving mechanical ventilation.

  4. Flow territory mapping of the cerebral arteries with regional perfusion MRI.

    Science.gov (United States)

    Hendrikse, Jeroen; van der Grond, Jeroen; Lu, Hanzhang; van Zijl, Peter C M; Golay, Xavier

    2004-04-01

    Conventional contrast-enhanced angiography is the gold standard for visualization of the vascular tree supplied by the major cerebral arteries and assessment of collateral flow. Thus far, however, no methods are available to assess the actual flow territories of the individual cerebral arteries. In the present study, we evaluate a noninvasive arterial spin labeling MRI method for selective mapping of the flow territories of the left and right internal carotid arteries and posterior circulation (basilar artery and vertebral arteries). A spatially selective labeling approach, regional perfusion imaging, was developed on the basis of selective slab inversion of the arterial water with a pulsed arterial spin labeling sequence. The selectivity of this method was demonstrated. Regional perfusion imaging enables assessment of the perfusion territories of the major cerebral arteries. With selective labeling of an internal carotid artery, signal is present in both the ipsilateral anterior cerebral artery and ipsilateral middle cerebral artery flow territory. With labeling of the basilar artery, perfusion-weighted signal is symmetrically present in both posterior cerebral artery flow territories. Cerebral blood flow values measured with regional perfusion imaging in the complete hemisphere (40.1 mL x min(-1) x 100 g(-1) tissue), white matter (22.1 mL x min(-1) x 100 g(-1) tissue), and gray matter (65.8 mL x min(-1) x 100 g(-1) tissue) are in agreement with data in the literature. We present the first imaging method capable of evaluating both quantitatively and qualitatively the flow territories of the individual brain-feeding arteries in vivo.

  5. The Relation Between Perfusion Pattern of Hepatic Artery Perfusion Scintigraphy and Response to Y-90 Microsphere Therapy

    Directory of Open Access Journals (Sweden)

    Bilge Volkan-Salancı

    2013-12-01

    Full Text Available Objective: Hepatic artery perfusion scintigraphy is a routine procedure for patient evaluation before Y-90 radiomicrosphere therapy and mostly used for prediction of extrahepatic leakage. Moreover, it also displays perfusion pattern of tumours, which is an important parameter on success of the therapy. The aim of this study is to assess the relation between the perfusion pattern on hepatic artery perfusion scintigraphy and radiomicrosphere therapy response. Methods: A total of 99 radiomicrosphere therapy applications were carried out in 80 patients (M/F: 55/25. Results: Heterogeneous and diffuse perfusion patterns were observed in 47 patients and 52 patients, respectively. The patients with diffuse perfusion pattern had better therapy response both on FDG PET/CT (p= 0.04 and CT (p=0.008 when compared to those with heterogenous perfusion pattern. Conclusion: Perfusion pattern observed on hepatic artery perfusion scintigraphy may be a successful predictor of early response to radiomicrosphere therapy

  6. Detection of functional structures in isolated perfused pig heart: methods and technical principles

    Science.gov (United States)

    Hiller, Michael; Rauh, Robert; Trinks, Tobias; Kessler, Manfred D.

    2002-06-01

    Light scattering in living heart tissue is mainly caused by mitochondria, but also by actin and myosin filaments, glycogen particles and others. In living tissue these subcellular structures are not stable but rather in a permanent change. Thus, one should be able to perceive the status of scattering structures by measurement of backscattered light in microvolumes. Our recent efforts aimed at detecting these structures by use of micro lightguides and scanning tissue spectroscopy technique (EMPHO II SSK) at isolated perfused pig hearts. The paper describes the technical principles of the scanning technique and gives an overview of our latest results.

  7. Myocardial perfusion imaging with dual energy CT

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); De Cecco, Carlo N. [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncology and Pathology, University of Rome “Sapienza”, Rome (Italy); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Spandorfer, Adam; Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States)

    2016-10-15

    Highlights: • Stress dual-energy sCTMPI offers the possibility to directly detect the presence of myocardial perfusion defects. • Stress dual-energy sCTMPI allows differentiating between reversible and fixed myocardial perfusion defects. • The combination of coronary CT angiography and dual-energy sCTMPI can improve the ability of CT to detect hemodynamically relevant coronary artery disease. - Abstract: Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  8. Beam hardening correction in CT myocardial perfusion measurement

    Science.gov (United States)

    So, Aaron; Hsieh, Jiang; Li, Jian-Ying; Lee, Ting-Yim

    2009-05-01

    This paper presents a method for correcting beam hardening (BH) in cardiac CT perfusion imaging. The proposed algorithm works with reconstructed images instead of projection data. It applies thresholds to separate low (soft tissue) and high (bone and contrast) attenuating material in a CT image. The BH error in each projection is estimated by a polynomial function of the forward projection of the segmented image. The error image is reconstructed by back-projection of the estimated errors. A BH-corrected image is then obtained by subtracting a scaled error image from the original image. Phantoms were designed to simulate the BH artifacts encountered in cardiac CT perfusion studies of humans and animals that are most commonly used in cardiac research. These phantoms were used to investigate whether BH artifacts can be reduced with our approach and to determine the optimal settings, which depend upon the anatomy of the scanned subject, of the correction algorithm for patient and animal studies. The correction algorithm was also applied to correct BH in a clinical study to further demonstrate the effectiveness of our technique.

  9. Computed tomography perfusion imaging denoising using Gaussian process regression

    International Nuclear Information System (INIS)

    Zhu Fan; Gonzalez, David Rodriguez; Atkinson, Malcolm; Carpenter, Trevor; Wardlaw, Joanna

    2012-01-01

    Brain perfusion weighted images acquired using dynamic contrast studies have an important clinical role in acute stroke diagnosis and treatment decisions. However, computed tomography (CT) images suffer from low contrast-to-noise ratios (CNR) as a consequence of the limitation of the exposure to radiation of the patient. As a consequence, the developments of methods for improving the CNR are valuable. The majority of existing approaches for denoising CT images are optimized for 3D (spatial) information, including spatial decimation (spatially weighted mean filters) and techniques based on wavelet and curvelet transforms. However, perfusion imaging data is 4D as it also contains temporal information. Our approach using Gaussian process regression (GPR), which takes advantage of the temporal information, to reduce the noise level. Over the entire image, GPR gains a 99% CNR improvement over the raw images and also improves the quality of haemodynamic maps allowing a better identification of edges and detailed information. At the level of individual voxel, GPR provides a stable baseline, helps us to identify key parameters from tissue time-concentration curves and reduces the oscillations in the curve. GPR is superior to the comparable techniques used in this study. (note)

  10. Tc99m-sestamibi dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Toledo, Janine M.; Trindade, Bruno M.; Campos, Tarcisio P.R.

    2015-01-01

    This paper addressed myocardial perfusion imaging providing a spatial dosimetric investigation of the 99m Tc-radiopharmaceutical dose distribution at the myocardium. Radiological data manipulation was performed in order to create a computational voxel model of the heart. A set of images obtained by thoracic angiotomography and abdominal aorta was set up providing anatomic and functional information for heart modeling in SISCODES code. A homogeneous distribution of 99m Tc was assumed into the cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissues were performed on the MCNP - Monte Carlo Code. The spatial dose distribution in the heart model is displayed as well as the dose versus volume histogram of the heart muscle. The present computational tools can generate spatial doses distribution in myocardial perfusion imaging. Specially, the dosimetry performed elucidates imparted dose distribution in the myocardial muscle per unit of injected 99m Tc activity, which can contribute to future deterministic effect investigations. (author)

  11. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    and represents a supplement and alternative to animal testing, bypassing the animal to human extrapolation. Placentas are readily obtainable from most births upon informed consent from the mothers and are considered a promising tissue alternative/supplement to animal experiments. The system is validated...... as a part of work package 2 of the integrated project ReProTect....

  12. Dynamic perfusion patterns in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Patrick; Paesschen, Wim van [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); Zaknun, John J. [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); University Hospital of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Maes, Alex [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); AZ Groeninge, Nuclear Medicine, Kortrijk (Belgium); Tepmongkol, Supatporn; Locharernkul, Chaichon [Chulalongkorn University, Nuclear Medicine and Neurology, Bangkok (Thailand); Vasquez, Silvia; Carpintiero, Silvina [Fleni Instituto de Investigaciones Neurologicas, Nuclear Medicine, Buenos Aires (Argentina); Bal, C.S. [All India Institute of Medical Sciences, Nuclear Medicine, New Delhi (India); Dondi, Maurizio [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); Ospedale Maggiore, Nuclear Medicine, Bologna (Italy)

    2009-05-15

    To investigate dynamic ictal perfusion changes during temporal lobe epilepsy (TLE). We investigated 37 patients with TLE by ictal and interictal SPECT. All ictal injections were performed within 60 s of seizure onset. Statistical parametric mapping was used to analyse brain perfusion changes and temporal relationships with injection time and seizure duration as covariates. The analysis revealed significant ictal hyperperfusion in the ipsilateral temporal lobe extending to subcortical regions. Hypoperfusion was observed in large extratemporal areas. There were also significant dynamic changes in several extratemporal regions: ipsilateral orbitofrontal and bilateral superior frontal gyri and the contralateral cerebellum and ipsilateral striatum. The study demonstrated early dynamic perfusion changes in extratemporal regions probably involved in both propagation of epileptic activity and initiation of inhibitory mechanisms. (orig.)

  13. Pulmonary perfusion patterns and pulmonary arterial pressure.

    Science.gov (United States)

    Scott, James A

    2002-08-01

    To use artificial intelligence methods to determine whether quantitative parameters describing the perfusion image can be synthesized to make a reasonable estimate of the pulmonary arterial (PA) pressure measured at angiography. Radionuclide perfusion images were obtained in 120 patients with normal chest radiographs who also underwent angiographic PA pressure measurement within 3 days of the radionuclide study. An artificial neural network (ANN) was constructed from several image parameters describing statistical and boundary characteristics of the perfusion images. With use of a leave-one-out cross-validation technique, this method was used to predict the PA systolic pressure in cases on which the ANN had not been trained. A Pearson correlation coefficient was determined between the predicted and measured PA systolic pressures. ANN predictions correlated with measured pulmonary systolic pressures (r = 0.846, P artificial intelligence methods helps to reveal physiologic information not readily apparent at visual image inspection. Copyright RSNA, 2002

  14. The significance of inadequate transcranial Doppler studies in children with sickle cell disease.

    Directory of Open Access Journals (Sweden)

    Simon Greenwood

    Full Text Available Sickle cell disease (SCD is a common cause of cerebrovascular disease in childhood. Primary stroke prevention is effective using transcranial Doppler (TCD scans to measure intracranial blood velocities, and regular blood transfusions or hydroxycarbamide when these are abnormal. Inadequate TCD scans occur when it is not possible to measure velocities in all the main arteries. We have investigated the prevalence and significance of this in a retrospective audit of 3915 TCD scans in 1191 children, performed between 2008 and 2015. 79% scans were normal, 6.4% conditional, 2.8% abnormal and 12% inadequate. 21.6% of 1191 patients had an inadequate scan at least once. The median age of first inadequate scan was 3.3 years (0.7-19.4, with a U-shaped frequency distribution with age: 28% aged 2-3 years, 3.5% age 10 years, 25% age 16 years. In young children reduced compliance was the main reason for inadequate TCDs, whereas in older children it was due to a poor temporal ultrasound window. The prevalence of inadequate TCD was 8% in the main Vascular Laboratory at King's College Hospital and significantly higher at 16% in the outreach clinics (P<0.0001, probably due to the use of a portable ultrasound machine. Inadequate TCD scans were not associated with underlying cerebrovascular disease.

  15. Estimation of Radiation Exposure of 128-Slice 4D-Perfusion CT for the Assessment of Tumor Vascularity

    International Nuclear Information System (INIS)

    Ketelsen, Dominik; Horger, Marius; Buchgeister, Markus; Fenchel, Michael; Thomas, Christoph; Boehringer, Nadine; Schulze, Maximilian; Tsiflikas, Ilias; Claussen, Claus D.; Heuschmid, Martin

    2010-01-01

    We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D Perfusion-CT. Phantom measurements were performed on a 128-slice single source scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans

  16. Estimation of Radiation Exposure of 128-Slice 4D-Perfusion CT for the Assessment of Tumor Vascularity

    Science.gov (United States)

    Horger, Marius; Buchgeister, Markus; Fenchel, Michael; Thomas, Christoph; Boehringer, Nadine; Schulze, Maximilian; Tsiflikas, Ilias; Claussen, Claus D.; Heuschmid, Martin

    2010-01-01

    Objective We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. Materials and Methods An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D-Perfusion-CT. Phantom measurements were performed on a 128-slice single-source scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). Results Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. Conclusion Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans. PMID:20808699

  17. Estimation of Radiation Exposure of 128-Slice 4D-Perfusion CT for the Assessment of Tumor Vascularity

    Energy Technology Data Exchange (ETDEWEB)

    Ketelsen, Dominik; Horger, Marius; Buchgeister, Markus; Fenchel, Michael; Thomas, Christoph; Boehringer, Nadine; Schulze, Maximilian; Tsiflikas, Ilias; Claussen, Claus D.; Heuschmid, Martin [University Hospital Tuebingen, Tuebingen (Germany)

    2010-10-15

    We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D Perfusion-CT. Phantom measurements were performed on a 128-slice single source scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans

  18. Quantitative dual energy CT measurements in rabbit VX2 liver tumors: Comparison to perfusion CT measurements and histopathological findings

    International Nuclear Information System (INIS)

    Zhang, Long Jiang; Wu, Shengyong; Wang, Mei; Lu, Li; Chen, Bo; Jin, Lixin; Wang, Jiandong; Larson, Andrew C.; Lu, Guang Ming

    2012-01-01

    Purpose: To evaluate the correlation between quantitative dual energy CT and perfusion CT measurements in rabbit VX2 liver tumors. Materials and methods: This study was approved by the institutional animal care and use committee at our institution. Nine rabbits with VX2 liver tumors underwent contrast-enhanced dual energy CT and perfusion CT. CT attenuation for the tumors and normal liver parenchyma and tumor-to-liver ratio were obtained at the 140 kVp, 80 kVp, average weighted images and dual energy CT iodine maps. Quantitative parameters for the viable tumor and adjacent liver were measured with perfusion CT. The correlation between the enhancement values of the tumor in iodine maps and perfusion CT parameters of each tumor was analyzed. Radiation dose from dual energy CT and perfusion CT was measured. Results: Enhancement values for the tumor were higher than that for normal liver parenchyma at the hepatic arterial phase (P < 0.05). The highest tumor-to-liver ratio was obtained in hepatic arterial phase iodine map. Hepatic blood flow of the tumor was higher than that for adjacent liver (P < 0.05). Enhancement values of hepatic tumors in the iodine maps positively correlated with permeability of capillary vessel surface (r = 0.913, P < 0.001), hepatic blood flow (r = 0.512, P = 0.010), and hepatic blood volume (r = 0.464, P = 0.022) at the hepatic arterial phases. The effective radiation dose from perfusion CT was higher than that from DECT (P < 0.001). Conclusions: The enhancement values for viable tumor tissues measured in iodine maps were well correlated to perfusion CT measurements in rabbit VX2 liver tumors. Compared with perfusion CT, dual energy CT of the liver required a lower radiation dose.

  19. Optimization of perfusion studies using Atropine

    International Nuclear Information System (INIS)

    Alvarado, A.N.; Valle, V.M.; Montoya, M.J.; Eskenazi, E.S.; Montiel, M.L.; Cueto, C.C.

    2002-01-01

    The studies of myocardial perfusion require an adequate stress; exercise or pharmacological. Every day, more pharmacological studies are performed, specially in some group of patients (women, AMI, etc). There some drugs that are used for this purpose, as adenosine and dobutamine. However, their cost and the lack of availability and infrastructure in our country do not allow there routinely use. We performed dipyridamol as a pharmacological stress, however in some patients there is a doubt regarding if the pharmacological effect was adequate. Atropine is a drug that is frequently used for different purpose and it is well know its tachycardic response. We present and alternative technique, using dipyridamol-atropine as a protocol of stress perfusion study. Our goal was to correlate the standard dipyridamol -thallium perfusion study and the dipyridamol -atropine-perfusion in patients with chronic coronary disease. We evaluated 6 patients (5 males) with stable angina and chronic coronary disease. A standard dipyridamol-thallium study was performed in all of them. Dipyridamole was administered intravenously at a rate of 0.14 mg/kg/min over 6 min for a total of 0.84 mg/kg body weight. Blood pressure, heart rate, EKG and symptoms were monitored before, during and after the pharmacological infusion. Two minutes after the infusion was completed, the radiotracer was injected intravenously. In the next 6 months, without any modification of the clinical situation (symptoms and therapy) a new dipyridamol study was performed, using 1 mg of atropine after the administration of dipyridamol. There were no differences in the collateral effects and we observed and average increase of 30% in the heart rate in relation with the study using dipyridamol alone. The addition of atropine to the standard dipyridamol perfusion study is safe, cheaper and improved the detection of perfusion defects in patients with coronary artery disease

  20. Cerebral perfusion imaging in HIV positive patients

    International Nuclear Information System (INIS)

    Kundley, Kshama; Chowdhury, D.; Lele, V.R.; Lele, R.D.

    1998-01-01

    Full text: Twelve human immunodeficiency virus (HIV) positive patients were studied by SPECT cerebral perfusion imaging 1 hour post injection of 15 mCi of 99m Tc-ECD under ideal conditions with a triple head gamma camera (Prism 3000 X P LEUHR), fanbeam collimators followed by Folstein Mini Mental Status Examination (FMMSE) and AIDS dementia complex (ADC) staging on the same day. All 12 patients were male, in the age range of 23-45 y (mean 31 y). The infected status was diagnosed by ELISA (10 patients) or Western blot (5 patients). The interval between diagnosis and imaging ranged from 1 month - 35 months (mean 15.3 months). Two patients were alcoholic and 2 were smokers. None of them had CNS disorder clinically. ADC staging and FMMSE could be performed in 4 patients. Two patients were normal (stage 0) and 2 were subclinical (stage 0.5) on ADC staging. FMMSE revealed normal or near normal status (mean score 35; maximum score 36). Cerebral perfusion images were interpreted simultaneously by 3 observers blind towards history and examination using semi-quantitative and quantitative methods by consensus. It revealed multiple areas of hypoperfusion, viz. temporal (11 patients (91 %), parietal 10 patients (83%), frontal 9 patients (75%, pre and post central gyrus 7 patients (58%), occipital 6 patients (50%) cingulate gyrus and cerebellum 5 patients (41%) and thalamic in 2 patients (16%). Hyper perfusion in caudate nuclei was noted in 10 patients (83%). The study reveals presence of multiple perfusion abnormalities on cerebral perfusion imaging in HIV positive patients who have normal/near normal mental status suggesting precedence of perfusion abnormality over clinically apparent mental deficit

  1. Predictors of Inadequate Inpatient Colonoscopy Preparation and Its Association with Hospital Length of Stay and Costs.

    Science.gov (United States)

    Yadlapati, Rena; Johnston, Elyse R; Gregory, Dyanna L; Ciolino, Jody D; Cooper, Andrew; Keswani, Rajesh N

    2015-11-01

    Adequate bowel preparation is essential to safe and effective inpatient colonoscopy. Predictors of poor inpatient colonoscopy preparation and the economic impacts of inadequate inpatient preparations are not defined. The aims of this study were to (1) determine risk factors for inadequate inpatient bowel preparations, and (2) examine the association between inadequate inpatient bowel preparation and hospital length of stay (LOS) and costs. We performed a retrospective cohort study of adult patients undergoing inpatient colonoscopy preparation over 12 months (1/1/2013-12/31/2013). Of 524 identified patients, 22.3% had an inadequate preparation. A multiple logistic regression model identified the following potential predictors of inadequate bowel preparation: lower income (OR 1.11; 95% CI 1.04, 1.22), opiate or tricyclic antidepressant (TCA) use (OR 1.55; 0.98, 2.46), and afternoon colonoscopy (OR 1.66; 1.07, 2.59); as well as American Society of Anesthesiologists (ASA) class ≥3 (OR 1.15; 1.05, 1.25) and symptoms of nausea/vomiting (OR 1.14; 1.04, 1.25) when a fair preparation was considered inadequate. Inadequate bowel preparation was associated with significantly increased hospital LOS (model relative mean estimate 1.25; 95% CI 1.03, 1.51) and hospital costs (estimate 1.31; 1.03, 1.67) when compared to adequate preparations. The rate of inadequate inpatient bowel preparations is high and associated with a significant increase in hospital LOS and costs. We identified five potential predictors of inadequate inpatient preparation: lower socioeconomic class, opiate/TCA use, afternoon colonoscopies, ASA class ≥3, and pre-preparation nausea/vomiting; these data should guide future initiatives to improve the quality of inpatient bowel preparations.

  2. Meta-Analysis of Stress Myocardial Perfusion Imaging

    Science.gov (United States)

    2017-06-06

    Coronary Disease; Echocardiography; Fractional Flow Reserve, Myocardial; Hemodynamics; Humans; Magnetic Resonance Imaging; Myocardial Perfusion Imaging; Perfusion; Predictive Value of Tests; Single Photon Emission Computed Tomography; Positron Emission Tomography; Multidetector Computed Tomography; Echocardiography, Stress; Coronary Angiography

  3. Functional MRI for characterization of renal perfusion impairment and edema formation due to acute kidney injury in different mouse strains.

    Science.gov (United States)

    Tewes, Susanne; Gueler, Faikah; Chen, Rongjun; Gutberlet, Marcel; Jang, Mi-Sun; Meier, Martin; Mengel, Michael; Hartung, Dagmar; Wacker, Frank; Rong, Song; Hueper, Katja

    2017-01-01

    The purpose was to characterize acute kidney injury (AKI) in C57BL/6 (B6)- and 129/Sv (Sv)-mice by noninvasive measurement of renal perfusion and tissue edema using functional MRI. Different severities of AKI were induced in B6- and Sv-mice by renal ischemia reperfusion injury (IRI). Unilateral clamping of the renal pedicle for 35 min (moderate AKI) or 45 min (severe AKI) was done. MRI (7-Tesla) was performed 1, 7 and 28 days after surgery using a flow alternating inversion recovery (FAIR) arterial spin labeling (ASL) sequence. Maps of perfusion and T1-relaxation time were calculated. Relative MRI-parameters of the IRI kidney compared to the contralateral not-clipped kidney were compared between AKI severities and between mouse strains using unpaired t-tests. In addition, fibrosis was assessed by Masson Trichrome and collagen IV staining. After moderate AKI relative perfusion impairment was significantly higher in B6- than in Sv-mice at d7 (55±7% vs. 82±8%, prenal cortex and outer stripe of outer medulla. Kidney volume loss (compared to the contralateral kidney) occurred already after 7 days but proceeded markedly towards 4 weeks in severe AKI. Early renal perfusion impairment was predictive for later kidney volume loss. The progression to chronic kidney disease (CKD) in the severe AKI model was similar in both mouse strains as revealed by histology. Quantification of renal perfusion and tissue edema by functional MRI allows characterization of strain differences upon AKI. Renal perfusion impairment was stronger in B6- compared to Sv-animals following moderate AKI. Prolonged ischemia times were associated with more severe perfusion impairment and edema formation in the early phase and progression to CKD within 4 weeks of observation.

  4. The correlation of contrast-enhanced ultrasound and MRI perfusion quantitative analysis in rabbit VX2 liver cancer.

    Science.gov (United States)

    Xiang, Zhiming; Liang, Qianwen; Liang, Changhong; Zhong, Guimian

    2014-12-01

    Our objective is to explore the value of liver cancer contrast-enhanced ultrasound (CEUS) and MRI perfusion quantitative analysis in liver cancer and the correlation between these two analysis methods. Rabbit VX2 liver cancer model was established in this study. CEUS was applied. Sono Vue was applied in rabbits by ear vein to dynamically observe and record the blood perfusion and changes in the process of VX2 liver cancer and surrounding tissue. MRI perfusion quantitative analysis was used to analyze the mean enhancement time and change law of maximal slope increasing, which were further compared with the pathological examination results. Quantitative indicators of liver cancer CEUS and MRI perfusion quantitative analysis were compared, and the correlation between them was analyzed by correlation analysis. Rabbit VX2 liver cancer model was successfully established. CEUS showed that time-intensity curve of rabbit VX2 liver cancer showed "fast in, fast out" model while MRI perfusion quantitative analysis showed that quantitative parameter MTE of tumor tissue increased and MSI decreased: the difference was statistically significant (P quantitative analysis were not significantly different (P > 0.05). However, the quantitative parameter of them were significantly positively correlated (P quantitative analysis can both dynamically monitor the liver cancer lesion and surrounding liver parenchyma, and the quantitative parameters of them are correlated. The combined application of both is of importance in early diagnosis of liver cancer.

  5. CT angiography and CT perfusion in acute ischemic stroke

    NARCIS (Netherlands)

    Seeters, T. van

    2016-01-01

    CT angiography and CT perfusion are used in patients with acute ischemic stroke for diagnostic purposes and to select patients for treatment. In this thesis, the reproducibility of CT angiography and CT perfusion is examined, the additional value of CT angiography and CT perfusion for stroke outcome

  6. Automatic Detection of Myocardial Boundaries in MR Cardio Perfusion Images

    NARCIS (Netherlands)

    Spreeuwers, Luuk; Breeuwer, Marcel

    2001-01-01

    Cardiovascular diseases often result in reduced blood perfusion of the myocardium (MC). Recent advances in MR allow fast recordingof contrast enhanced myocardial perfusion scans. For perfusion analysis the myocardial boundaries must be traced. Currently this is done manually. In this paper a method

  7. Increased sinusoidal volume and solute extraction during retrograde liver perfusion

    International Nuclear Information System (INIS)

    Bass, N.M.; Manning, J.A.; Weisiger, R.A.

    1989-01-01

    Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of [ 14 C]sucrose washout during perfusion as well as by direct measurement of [ 14 C]sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the [ 14 C]sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver

  8. An alternative method for neonatal cerebro-myocardial perfusion

    Science.gov (United States)

    Luciani, Giovanni Battista; De Rita, Fabrizio; Faggian, Giuseppe; Mazzucco, Alessandro

    2012-01-01

    Several techniques have already been described for selective cerebral perfusion during repair of aortic arch pathology in children. One method combining cerebral with myocardial perfusion has also been proposed. A novel technique is reported here for selective and independent cerebro-myocardial perfusion for neonatal and infant arch surgery. Technical aspects and potential advantages are discussed. PMID:22307393

  9. Quality control in tissue banking--ensuring the safety of allograft tissues.

    Science.gov (United States)

    Humphries, Linda K; Mansavage, Vicki L

    2006-09-01

    DESPITE FEDERAL REGULATIONS for tissue-banking practices, inadequate quality control led to the largest allograft tissue recall in history in October 2005. THE RECALL INCLUDED all allograft tissues obtained from 761 donors and distributed by five tissue banks. Many of these tissues already had been implanted and were unrecoverable. THIS ARTICLE DESCRIBES the many tissue-banking industry variables, including donor selection and testing and tissue recovery, processing, and preservation. QUESTIONS THAT HEALTH CARE providers can ask to determine which tissue banks' quality control measures best ensure the safety of the allografts they provide also are included.

  10. Metastases to the Liver from Neuroendocrine Tumors: Effect of Duration of Scan Acquisition on CT Perfusion Values

    Science.gov (United States)

    Hobbs, Brian P.; Chandler, Adam G.; Anderson, Ella F.; Herron, Delise H.; Charnsangavej, Chusilp; Yao, James

    2013-01-01

    Purpose To assess the effects of acquisition duration on computed tomographic (CT) perfusion parameter values in neuroendocrine liver metastases and normal liver tissue. Materials and Methods This retrospective study was institutional review board approved, with waiver of informed consent. CT perfusion studies in 16 patients (median age, 57.5 years; range, 42.0–69.7 years), including six men (median, 54.1 years; range, 42.0–69.7), and 10 women (median, 59.3 years; range 43.6–66.3), with neuroendocrine liver metastases were analyzed by means of distributed parametric modeling to determine tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction for tumors and normal liver tissue. Analyses were undertaken with acquisition time of 12–590 seconds. Nonparameteric regression analyses were used to evaluate the functional relationships between CT perfusion parameters and acquisition duration. Evidence for time invariance was evaluated for each parameter at multiple time points by inferring the fitted derivative to assess its proximity to zero as a function of acquisition time by using equivalence tests with three levels of confidence (20%, 70%, and 90%). Results CT perfusion parameter values varied, approaching stable values with increasing acquisition duration. Acquisition duration greater than 160 seconds was required to obtain at least low confidence stability in any of the CT perfusion parameters. At 160 seconds of acquisition, all five CT perfusion parameters stabilized with low confidence in tumor and normal tissues, with the exception of hepatic arterial fraction in tumors. After 220 seconds of acquisition, there was stabilization with moderate confidence for blood flow, blood volume, and hepatic arterial fraction in tumors and normal tissue, and for mean transit time in tumors; however, permeability values did not satisfy the moderate stabilization criteria in both tumors and normal tissue until 360 seconds of

  11. Automated scoring of regional lung perfusion in children from contrast enhanced 3D MRI

    Science.gov (United States)

    Heimann, Tobias; Eichinger, Monika; Bauman, Grzegorz; Bischoff, Arved; Puderbach, Michael; Meinzer, Hans-Peter

    2012-03-01

    MRI perfusion images give information about regional lung function and can be used to detect pulmonary pathologies in cystic fibrosis (CF) children. However, manual assessment of the percentage of pathologic tissue in defined lung subvolumes features large inter- and intra-observer variation, making it difficult to determine disease progression consistently. We present an automated method to calculate a regional score for this purpose. First, lungs are located based on thresholding and morphological operations. Second, statistical shape models of left and right children's lungs are initialized at the determined locations and used to precisely segment morphological images. Segmentation results are transferred to perfusion maps and employed as masks to calculate perfusion statistics. An automated threshold to determine pathologic tissue is calculated and used to determine accurate regional scores. We evaluated the method on 10 MRI images and achieved an average surface distance of less than 1.5 mm compared to manual reference segmentations. Pathologic tissue was detected correctly in 9 cases. The approach seems suitable for detecting early signs of CF and monitoring response to therapy.

  12. A direct comparison of the sensitivity of CT and MR cardiac perfusion using a myocardial perfusion phantom.

    OpenAIRE

    Otton, James; Morton, Geraint; Schuster, Andreas; Bigalke, Boris; Marano, Riccardo; Olivotti, Luca; Nagel, Eike; Chiribiri, Amedeo

    2013-01-01

    BACKGROUND: Direct comparison of CT and magnetic resonance (MR) perfusion techniques has been limited and in vivo assessment is affected by physiological variability, timing of image acquisition, and parameter selection. OBJECTIVE: We precisely compared high-resolution k-t SENSE MR cardiac perfusion at 3 T with single-phase CT perfusion (CTP) under identical imaging conditions. METHODS: We used a customized MR imaging and CT compatible dynamic myocardial perfusion phantom to represe...

  13. Behaviorally inadequate

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2014-01-01

    According to situationism in psychology, behavior is primarily influenced by external situational factors rather than internal traits or motivations such as virtues. Environmental ethicists wish to promote pro-environmental behaviors capable of providing adequate protection for the environment......, but situationist critiques suggest that character traits, and environmental virtues, are not as behaviorally robust as is typically supposed. Their views present a dilemma. Because ethicists cannot rely on virtues to produce pro-environmental behaviors, the only real way of salvaging environmental virtue theory...... positive results. However, because endorsing behaviorally ineffective virtues, for whatever reason, entails that environmental ethicists are abandoning the goal of helping and protecting the environment, environmental ethicists should consider looking elsewhere than virtues and focus instead on the role...

  14. Application of the steepest slope model reveals different perfusion territories within the mouse placenta.

    Science.gov (United States)

    Remus, C C; Sedlacik, J; Wedegaertner, U; Arck, P; Hecher, K; Adam, G; Forkert, N D

    2013-10-01

    The steepest slope model is a numerically robust and fast method for perfusion quantification. The purpose of this study was to evaluate if the steepest slope model can be used for quantifying placental perfusion in mice based on dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) datasets. T1-weighted DCE MRI was performed in 5 pregnant BALB/c mice on gestation day (gd) 14.5 and in 5 mice on gd 16.5 using a 7T small animal MRI scanner. The placentas were manually delineated in the DCE datasets and the arterial input function (AIF) was selected from the kidney hilus. Placental perfusion was determined on a voxel-by-voxel basis using the steepest slope model. Perfusion was averaged over the entire placenta as well as separately calculated for the high-flow compartment within the central labyrinth zone and for the remaining low-flow placenta tissue. The AIF selection was independently performed by two observers for assessment of inter-observer differences. Mean perfusion on gd 14.5 was 135 ml/min/100 ml (standard deviation SD: 29 ml/min/100 ml placenta) and 112 ml/min/100 ml on gd 16.5 for the whole placenta (SD: 32 ml/min/100 ml). Perfusion in the high flow compartment in the central labyrinth was significantly higher (p ≤ 0.002) than in the low-flow compartment including the remaining placenta tissue: 184 ml/min/100 ml (SD: 39 ml/min/100 ml) vs. 119 ml/min/100 ml (SD 28 ml/min/100 ml) on gd 14.5 and 158 ml/min/100 ml (SD: 58 ml/min/100 ml) vs. 114 ml/min/100 ml (SD: 52 ml/min/100 ml of placenta) on gd 16.5. The mean relative inter-rater observer difference was 6%. The steepest slope model is a computationally simple method, which allows perfusion quantification in the mouse placenta. Furthermore, the results of this work indicate that the different placental compartments should be analyzed separately to prevent biased results due to averaging. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Reduced myocardial perfusion reserve in myocardium having coronary artery aneurysm of Kawasaki disease

    International Nuclear Information System (INIS)

    Yoon, S. N.; Lee, D. S.; Choi, J. Y.; Kil, H. R.; Jeong, Z. K.; Lee, M. C.; Ko, C. S.

    1997-01-01

    Kawasaki disease is a systemic vasculitis involving the coronary arteries at early childhood and cause coronary artery aneurysms and thrombotic occlusions. These coronary artery aneurysms were usually transformed later into stenotic or obstructive lesions, however, the majority of these aneurysms, even the giant ones, are known to be associated with normal epicardial coronary flow. Flow reserve is difficult to assess in aneurysmal arteries with echo or angiography. We performed this study to question if there are abnormalities in flow reserve in myocardial tissue with normal epicardial arterial flow on angiography in patients with Kawasaki disease, dipyridamole stress and rest Tc-99m-sestamibi SPECT were performed in 37 patients (28 boys, 9 girls, mean age 6.6 years). We compared SPECT findings with coronary angiography (CAG) findings in 21 patients who did both studies after finding abnormality on echocardiaography. On CAG, aneurysms were found in 26 arteries of 16 patients, i.e., 10 left main arteries, 6 left anterior descending arteries (LAD), 2 left circumflex arteries (LCX), and 8 right coronary arteries (RCA). Localized and segmental stenotic lesions were found in 11 arteries in 9 patients (LAD: 4, LCX: 1, RCA: 6). Eight of the 10 patients with aneurysms had no obvious stenosis. On stress-rest SPECT, 16(43%) out of 37 patients showed normal perfusion and the other 21(57%) showed reversible or persistent decrease. Among 11 stenotic artery territories, 3(27%) showed persistent and/or reversible perfusion defects. The other 8 were normal. Among 26 aneurysmal artery territories, 12 artery territories showe perfusion decrease. Three of the 5 patients with normal CAG showed persistent and/or transient perfusion defects. Among 14 artery territories with perfusion decrease in the 16 patients, 3(21%) could be localized to vascular territory having stenosis of supplying coronary arteries, 12(86%) were related to the coronary artery aneurysms. Two were not related to

  16. Study of lung perfusion in colagenosis

    International Nuclear Information System (INIS)

    Macedo de Carvalho, A.C.; Calegaro, J.U.M.

    1982-01-01

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized. (author) [es

  17. Hypothermic machine perfusion in kidney transplantation

    NARCIS (Netherlands)

    De Deken, Julie; Kocabayoglu, Peri; Moers, Cyril

    Purpose of reviewThis article summarizes novel developments in hypothermic machine perfusion (HMP) as an organ preservation modality for kidneys recovered from deceased donors.Recent findingsHMP has undergone a renaissance in recent years. This renewed interest has arisen parallel to a shift in

  18. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    in all projections as well as in rotating volume images based upon maximum intensity projections. Probabilistic interpretation of V/Q SPECT should be replaced by a holistic interpretation strategy on the basis of all relevant information about the patient and all ventilation/perfusion patterns. PE...

  19. Nonrigid registration of myocardial perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrig...

  20. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul

    2010-01-01

    Validation of in vitro test systems using the modular approach with steps addressing reliability and relevance is an important aim when developing in vitro tests in e.g. reproductive toxicology. The ex vivo human placental perfusion system may be used for such validation, here presenting...

  1. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    for assessment of vascularity. CT perfusion has also been used for tumor characterization, staging of disease, response evaluation of newer drugs targeted towards angiogenesis and as a method for early detection of recurrence after radiation and embolization. There are several software solutions available...

  2. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas ov...

  3. Study of lung perfusion in colagenosis

    Energy Technology Data Exchange (ETDEWEB)

    Macedo de Carvalho, A.C.; Calegaro, J.U.M. (Fundacao Hospitalar do Distrito Federal, Distrito Federal (Brazil). Unidade de Medicina Nuclear)

    1982-07-01

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized.

  4. Nuclear cardiology: Myocardial perfusion and function

    International Nuclear Information System (INIS)

    Seldin, D.W.

    1991-01-01

    Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references

  5. Volume perfusion CT imaging of cerebral vasospasm: diagnostic performance of different perfusion maps

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Afat, Saif; Nikoubashman, Omid; Mueller, Marguerite; Wiesmann, Martin; Brockmann, Carolin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Schubert, Gerrit Alexander [RWTH Aachen University, Department of Neurosurgery, Aachen (Germany); Bier, Georg [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Brockmann, Marc A. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); University Hospital Mainz, Department of Neuroradiology, Mainz (Germany)

    2016-08-15

    In this study, we aimed to evaluate the diagnostic performance of different volume perfusion CT (VPCT) maps regarding the detection of cerebral vasospasm compared to angiographic findings. Forty-one datasets of 26 patients (57.5 ± 10.8 years, 18 F) with subarachnoid hemorrhage and suspected cerebral vasospasm, who underwent VPCT and angiography within 6 h, were included. Two neuroradiologists independently evaluated the presence and severity of vasospasm on perfusion maps on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting <50 %, 2 - vasospasm affecting >50 % of vascular territory). A third neuroradiologist independently assessed angiography for the presence and severity of vasospasm on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting < 50 %, 2 - vasospasm affecting > 50 % of vessel diameter). Perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to drain (TTD) were evaluated regarding diagnostic accuracy for cerebral vasospasm with angiography as reference standard. Correlation analysis of vasospasm severity on perfusion maps and angiographic images was performed. Furthermore, inter-reader agreement was assessed regarding findings on perfusion maps. Diagnostic accuracy for TTD and MTT was significantly higher than for all other perfusion maps (TTD, AUC = 0.832; MTT, AUC = 0.791; p < 0.001). TTD revealed higher sensitivity than MTT (p = 0.007). The severity of vasospasm on TTD maps showed significantly higher correlation levels with angiography than all other perfusion maps (p ≤ 0.048). Inter-reader agreement was (almost) perfect for all perfusion maps (kappa ≥ 0.927). The results of this study indicate that TTD maps have the highest sensitivity for the detection of cerebral vasospasm and highest correlation with angiography regarding the severity of vasospasm. (orig.)

  6. Evaluation of Primary Pulmonary Vein Stenosis in Children: Comparison of Radionuclide Perfusion Lung Scan and Angiography.

    Science.gov (United States)

    Drubach, Laura A; Jenkins, Kathy J; Stamoulis, Catherine; Palmer, Edwin L; Lee, Edward Y

    2015-10-01

    The purpose of this study was to evaluate the utility of radionuclide perfusion lung scanning in the evaluation of primary pulmonary vein stenosis (PVS) in pediatric patients by comparing it with angiography. We retrospectively identified pediatric patients with primary PVS who underwent both lung scanning and angiography. A cohort of 34 patients was evaluated. The presence of PVS in the right upper, right lower, left upper, and left lower pulmonary veins on angiograms was recorded. Two nuclear medicine physicians evaluated the lung scans for perfusion defects. Agreement between lung scan and angiographic findings was assessed with contingency tables. Sensitivity and specificity of lung scanning for accurate detection of PVS with angiographic findings as the reference standard were assessed by ROC analysis. Angiography depicted PVS in 90 of the total 136 pulmonary veins (66%). Lung scans correctly depicted 65 (72%) of the cases of PVS diagnosed with angiography. The sensitivity and specificity of lung scans were 76.0% and 88.9% for the right upper pulmonary vein, 70.6% and 94.1% for the right lower pulmonary vein, 77.3% and 58.3% for the left upper pulmonary vein, and 65.4% and 87.5% for the left lower pulmonary vein. Lung scan findings correlate with angiographic findings in the detection of primary PVS in pediatric patients. Perfusion lung scanning may have a role in angiographically diagnosed PVS by noninvasively showing relative perfusion at the tissue level.

  7. Fate of receptor-bound human chorionic gonadotrophin in pseudopregnant rat ovaries perfused in vitro

    International Nuclear Information System (INIS)

    Rajaniemi, H.; Sogn, J.; Holmes, P.; Kaellfelt, B.; Janson, P.O.

    1985-01-01

    Pseudopregnant rats were injected with [ 125 I] hCG, anaesthesized 1 h later and after cannulation of the aorta the ovaries were isolated and perfused with Gey and Gey buffer containing 0.2% BSA. The release of radioactivity was monitored for 2 h and analyzed by gel filtration. Five to ten per cent of the radioactivity was released within 2 h and represented small molecular weight peptides and iodotyrosine and [ 125 I]hCG. Analysis of the ovarian radioactivity prior to and after perfusion revealed that virtually all hCG was receptor-bound. Loading the medium with unlabelled hCG displaced [ 125 I]hCG from the receptor but did not enhance its degradation. Histological examination showed that the ovarian tissues were still intact after the 2 h perfusion. Immunohistochemical studies revealed a localization of the hCG at the cell periphery both prior to and after perfusion. These results provide evidence showing that the rate of internalization of receptor-hCG complexes in rat luteal cells is slow in vivo. (author)

  8. Assessment of drug disposition in the perfused rat brain by statistical moment analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, T.; Nakatsu, M.; Yamamoto, A.; Hashida, M.; Sezaki, H.; Yamashita, S.; Nadai, T. (Faculty of Pharmaceutical Sciences, Setsunan University, Osaka (Japan))

    1991-06-01

    Drug disposition in the brain was investigated by statistical moment analysis using an improved in situ brain perfusion technique. The right cerebral hemisphere of the rat was perfused in situ. The drug and inulin were injected into the right internal carotid artery as a rapid bolus and the venous outflow curve at the posterior facial vein was obtained. The infusion rate was adjusted to minimize the flow of perfusion fluid into the left hemisphere. The obtained disposition parameters were characteristics and considered to reflect the physicochemical properties of each drug. Antipyrine showed a small degree of initial uptake. Therefore, its apparent distribution volume (Vi) and apparent intrinsic clearance (CLint,i) were small. Diazepam showed large degrees of both influx and efflux and, thus, a large Vi. Water showed parameters intermediate between those of antipyrine and those of diazepam. Imipramine, desipramine, and propranolol showed a large CLint,i compared with those of the other drugs. The extraction ratio of propranolol significantly decreased with increasing concentrations of unlabeled propranolol in the perfusion fluid. These findings may be explained partly by the tissue binding of these drugs. In conclusion, the present method is useful for studying drug disposition in the brain.

  9. Assessment of drug disposition in the perfused rat brain by statistical moment analysis

    International Nuclear Information System (INIS)

    Sakane, T.; Nakatsu, M.; Yamamoto, A.; Hashida, M.; Sezaki, H.; Yamashita, S.; Nadai, T.

    1991-01-01

    Drug disposition in the brain was investigated by statistical moment analysis using an improved in situ brain perfusion technique. The right cerebral hemisphere of the rat was perfused in situ. The drug and inulin were injected into the right internal carotid artery as a rapid bolus and the venous outflow curve at the posterior facial vein was obtained. The infusion rate was adjusted to minimize the flow of perfusion fluid into the left hemisphere. The obtained disposition parameters were characteristics and considered to reflect the physicochemical properties of each drug. Antipyrine showed a small degree of initial uptake. Therefore, its apparent distribution volume (Vi) and apparent intrinsic clearance (CLint,i) were small. Diazepam showed large degrees of both influx and efflux and, thus, a large Vi. Water showed parameters intermediate between those of antipyrine and those of diazepam. Imipramine, desipramine, and propranolol showed a large CLint,i compared with those of the other drugs. The extraction ratio of propranolol significantly decreased with increasing concentrations of unlabeled propranolol in the perfusion fluid. These findings may be explained partly by the tissue binding of these drugs. In conclusion, the present method is useful for studying drug disposition in the brain

  10. Influence of red blood cell aggregation on perfusion of an artificial microvascular network.

    Science.gov (United States)

    Reinhart, Walter H; Piety, Nathaniel Z; Shevkoplyas, Sergey S

    2017-07-01

    RBCs suspended in plasma form multicellular aggregates under low-flow conditions, increasing apparent blood viscosity at low shear rates. It has previously been unclear, however, if RBC aggregation affects microvascular perfusion. Here, we analyzed the impact of RBC aggregation on perfusion and 'capillary' hematocrit in an AMVN at driving pressures ranging from 5 to 60 cm H 2 O to determine if aggregation could improve tissue oxygenation. RBCs were suspended at 30% hematocrit in either 46.5 g/L dextran 40 (D40, non-aggregating medium) or 35 g/L dextran 70 (D70, aggregating medium) solutions with equal viscosity. Aggregation was readily observed in the AMVN for RBCs suspended in D70 at driving pressures ≤40 cm H 2 O. The AMVN perfusion rate was the same for RBCs suspended in aggregating and non-aggregating medium, at both 'venular' and 'capillary' level. Estimated 'capillary' hematocrit was higher for D70 suspensions than for D40 suspensions at intermediate driving pressures (5-40 cm H 2 O). We conclude that although RBC aggregation did not affect the AMVN perfusion rate independently of the driving pressure, a higher hematocrit in the 'capillaries' of the network for D70 suspensions suggested a better oxygen transport capacity in the presence of RBC aggregation. © 2016 John Wiley & Sons Ltd.

  11. Image registration and analysis for quantitative myocardial perfusion: application to dynamic circular cardiac CT

    Science.gov (United States)

    Isola, A. A.; Schmitt, H.; van Stevendaal, U.; Begemann, P. G.; Coulon, P.; Boussel, L.; Grass, M.

    2011-09-01

    Large area detector computed tomography systems with fast rotating gantries enable volumetric dynamic cardiac perfusion studies. Prospectively, ECG-triggered acquisitions limit the data acquisition to a predefined cardiac phase and thereby reduce x-ray dose and limit motion artefacts. Even in the case of highly accurate prospective triggering and stable heart rate, spatial misalignment of the cardiac volumes acquired and reconstructed per cardiac cycle may occur due to small motion pattern variations from cycle to cycle. These misalignments reduce the accuracy of the quantitative analysis of myocardial perfusion parameters on a per voxel basis. An image-based solution to this problem is elastic 3D image registration of dynamic volume sequences with variable contrast, as it is introduced in this contribution. After circular cone-beam CT reconstruction of cardiac volumes covering large areas of the myocardial tissue, the complete series is aligned with respect to a chosen reference volume. The results of the registration process and the perfusion analysis with and without registration are evaluated quantitatively in this paper. The spatial alignment leads to improved quantification of myocardial perfusion for three different pig data sets.

  12. Computed Tomography Perfusion, Magnetic Resonance Imaging, and Histopathological Findings After Laparoscopic Renal Cryoablation: An In Vivo Pig Model.

    Science.gov (United States)

    Nielsen, Tommy Kjærgaard; Østraat, Øyvind; Graumann, Ole; Pedersen, Bodil Ginnerup; Andersen, Gratien; Høyer, Søren; Borre, Michael

    2017-08-01

    The present study investigates how computed tomography perfusion scans and magnetic resonance imaging correlates with the histopathological alterations in renal tissue after cryoablation. A total of 15 pigs were subjected to laparoscopic-assisted cryoablation on both kidneys. After intervention, each animal was randomized to a postoperative follow-up period of 1, 2, or 4 weeks, after which computed tomography perfusion and magnetic resonance imaging scans were performed. Immediately after imaging, open bilateral nephrectomy was performed allowing for histopathological examination of the cryolesions. On computed tomography perfusion and magnetic resonance imaging examinations, rim enhancement was observed in the transition zone of the cryolesion 1week after laparoscopic-assisted cryoablation. This rim enhancement was found to subside after 2 and 4 weeks of follow-up, which was consistent with the microscopic examinations revealing of fibrotic scar tissue formation in the peripheral zone of the cryolesion. On T2 magnetic resonance imaging sequences, a thin hypointense rim surrounded the cryolesion, separating it from the adjacent renal parenchyma. Microscopic examinations revealed hemorrhage and later hemosiderin located in the peripheral zone. No nodular or diffuse contrast enhancement was found in the central zone of the cryolesions at any follow-up stage on neither computed tomography perfusion nor magnetic resonance imaging. On microscopic examinations, the central zone was found to consist of coagulative necrosis 1 week after laparoscopic-assisted cryoablation, which was partially replaced by fibrotic scar tissue 4 weeks following laparoscopic-assisted cryoablation. Both computed tomography perfusion and magnetic resonance imaging found the renal collecting system to be involved at all 3 stages of follow-up, but on microscopic examination, the urothelium was found to be intact in all cases. In conclusion, cryoablation effectively destroyed renal parenchyma

  13. Cell sheet-based tissue engineering for fabricating 3-dimensional heart tissues.

    Science.gov (United States)

    Shimizu, Tatsuya

    2014-01-01

    In addition to stem cell biology, tissue engineering is an essential research field for regenerative medicine. In contrast to cell injection, bioengineered tissue transplantation minimizes cell loss and has the potential to repair tissue defects. A popular approach is scaffold-based tissue engineering, which utilizes a biodegradable polymer scaffold for seeding cells; however, new techniques of cell sheet-based tissue engineering have been developed. Cell sheets are harvested from temperature-responsive culture dishes by simply lowering the temperature. Monolayer or stacked cell sheets are transplantable directly onto damaged tissues and cell sheet transplantation has already been clinically applied. Cardiac cell sheet stacking produces pulsatile heart tissue; however, lack of vasculature limits the viable tissue thickness to 3 layers. Multistep transplantation of triple-layer cardiac cell sheets cocultured with endothelial cells has been used to form thick vascularized cardiac tissue in vivo. Furthermore, in vitro functional blood vessel formation within 3-dimensional (3D) tissues has been realized by successfully imitating in vivo conditions. Triple-layer cardiac cell sheets containing endothelial cells were layered on vascular beds and the constructs were media-perfused using novel bioreactor systems. Interestingly, cocultured endothelial cells migrate into the vascular beds and form perfusable blood vessels. An in vitro multistep procedure has also enabled the fabrication of thick, vascularized heart tissues. Cell sheet-based tissue engineering has revealed great potential to fabricate 3D cardiac tissues and should contribute to future treatment of severe heart diseases and human tissue model production.

  14. Ventilation-perfusion distribution in normal subjects.

    Science.gov (United States)

    Beck, Kenneth C; Johnson, Bruce D; Olson, Thomas P; Wilson, Theodore A

    2012-09-01

    Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.

  15. Ventilation and perfusion display in a single image

    International Nuclear Information System (INIS)

    Lima, J.J.P. de; Botelho, M.F.R.; Pereira, A.M.S.; Rafael, J.A.S.; Pinto, A.J.; Marques, M.A.T.; Pereira, M.C.; Baganha, M.F.; Godinho, F.

    1991-01-01

    A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms. (orig.)

  16. C-Arm Conebeam CT Perfusion Imaging in the Angiographic Suite: A Comparison with Multidetector CT Perfusion Imaging.

    Science.gov (United States)

    Niu, K; Yang, P; Wu, Y; Struffert, T; Doerfler, A; Schafer, S; Royalty, K; Strother, C; Chen, G-H

    2016-07-01

    Perfusion imaging in the angiography suite may provide a way to reduce time from stroke onset to endovascular revascularization of patients with large-vessel occlusion. Our purpose was to compare conebeam CT perfusion with multidetector CT perfusion. Data from 7 subjects with both multidetector CT perfusion and conebeam CT perfusion were retrospectively processed and analyzed. Two algorithms were used to enhance temporal resolution and temporal sampling density and reduce the noise of conebeam CT data before generating perfusion maps. Two readers performed qualitative image-quality evaluation on maps by using a 5-point scale. ROIs indicating CBF/CBV abnormalities were drawn. Quantitative analyses were performed by using the Sørensen-Dice coefficients to quantify the similarity of abnormalities. A noninferiority hypothesis was tested to compare conebeam CT perfusion against multidetector CT perfusion. Average image-quality scores for multidetector CT perfusion and conebeam CT perfusion images were 2.4 and 2.3, respectively. The average confidence score in diagnosis was 1.4 for both multidetector CT and conebeam CT; the average confidence scores for the presence of a CBV/CBF mismatch were 1.7 (κ = 0.50) and 1.5 (κ = 0.64). For multidetector CT perfusion and conebeam CT perfusion maps, the average scores of confidence in making treatment decisions were 1.4 (κ = 0.79) and 1.3 (κ = 0.90). The area under the visual grading characteristic for the above 4 qualitative quality scores showed an average area under visual grading characteristic of 0.50, with 95% confidence level cover centered at the mean for both readers. The Sørensen-Dice coefficient for CBF maps was 0.81, and for CBV maps, 0.55. After postprocessing methods were applied to enhance image quality for conebeam CT perfusion maps, the conebeam CT perfusion maps were not inferior to those generated from multidetector CT perfusion. © 2016 by American Journal of Neuroradiology.

  17. FAIR true-FISP perfusion imaging of the thyroid gland.

    Science.gov (United States)

    Schraml, Christina; Boss, Andreas; Martirosian, Petros; Schwenzer, Nina F; Claussen, Claus D; Schick, Fritz

    2007-07-01

    To evaluate the feasibility of quantitative perfusion MRI of the thyroid gland using an arterial spin labeling (ASL) method. An ASL technique with flow-sensitive alternating inversion-recovery (FAIR) spin preparation and a true fast imaging in the steady state (TrueFISP) signal readout strategy was implemented on a 1.5T whole-body unit. Anatomical and perfusion imaging of the thyroid gland was performed in eight healthy volunteers and one patient with functioning adenoma. Quantitative perfusion maps were calculated using the extended Bloch equations. In all subjects the perfusion images showed diagnostic image quality. The mean examination time was 24 minutes for multiplanar perfusion imaging of the entire thyroid gland. Individual perfusion values ranged between 341 +/- 91 and 640 +/- 90 mL/100 g/minute, with a mean perfusion of 461 +/- 90 mL/100 g/minute. The functioning adenoma showed markedly reduced perfusion compared to normal thyroidal parenchyma. No perfusion was noticeable inside four detected thyroid cysts. Quantitative ASL perfusion imaging of the thyroid gland using a FAIR-TrueFISP sequence leads to perfusion maps that may provide important information for assessing thyroid gland pathologies and monitoring therapeutic treatment. Copyright 2007 Wiley-Liss, Inc.

  18. Quantitative perfusion imaging in magnetic resonance imaging; Quantitative Perfusionsbildgebung in der Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Zoellner, F.G.; Gaa, T.; Zimmer, F. [Universitaet Heidelberg, Computerunterstuetzte Klinische Medizin, Medizinische Fakultaet Mannheim, Mannheim (Germany); Ong, M.M.; Riffel, P.; Hausmann, D.; Schoenberg, S.O.; Weis, M. [Universitaet Heidelberg, Institut fuer Klinische Radiologie und Nuklearmedizin, Universitaetsmedizin Mannheim, Medizinische Fakultaet Mannheim, Mannheim (Germany)

    2016-02-15

    Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.) [German] Die Magnetresonanztomographie (MRT) zeichnet sich durch einen ueberlegenen Gewebekontrast aus, waehrend sie nichtinvasiv und frei von ionisierender Strahlung ist. Sie bietet Zugang zu Gewebe- und Organfunktion. Eine dieser funktionellen bildgebenden Verfahren ist die Perfusionsbildgebung. Mit dieser Technik koennen u. a. Gewebeperfusion und Kapillarpermeabilitaet aus dynamischen Bilddaten bestimmt werden. Perfusionsbildgebung mithilfe der MRT kann durch 2 Ansaetze, naemlich ''arterial spin labeling'' (ASL) und dynamische kontrastverstaerkte (DCE-)MRT durchgefuehrt werden. Waehrend die erste Methode magnetisch

  19. Effect of prolonged hypokinesia on tissue blood flow

    Science.gov (United States)

    Levites, Z. P.; Fedotova, V. F.

    1979-01-01

    The influence of hypokinesia on the blood flow in the tissues of rabbits was studied. Motor activity of animals was restricted during 90 days and blood flow recorded through resorption rate of NaI-131. Perfusion of tissues under the influence of hypokinesia was found to be reduced.

  20. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    International Nuclear Information System (INIS)

    Dowdle, S.C.; Human, D.G.; Mann, M.D.

    1990-01-01

    Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis

  1. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    Energy Technology Data Exchange (ETDEWEB)

    Dowdle, S.C.; Human, D.G.; Mann, M.D. (Univ. of Cape Town (South Africa))

    1990-08-01

    Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis.

  2. Parametric investigation of heating due to magnetic fluid hyperthermia in a tumor with blood perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Liangruksa, Monrudee [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Ganguly, Ranjan [Department of Power Engineering, Jadavpur University, Kolkata 700098 (India); Puri, Ishwar K., E-mail: ikpuri@vt.ed [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States)

    2011-03-15

    Magnetic fluid hyperthermia (MFH) is a cancer treatment that can selectively elevate the tumor temperature without significantly damaging the surrounding healthy tissue. Optimal MFH design requires a fundamental parametric investigation of the heating of soft materials by magnetic fluids. We model the problem of a spherical tumor and its surrounding healthy tissue that are heated by exciting a homogeneous dispersion of magnetic nanoparticles infused only into the tumor with an external AC magnetic field. The key dimensionless parameters influencing thermotherapy are the Peclet, Fourier, and Joule numbers. Analytical solutions for transient and steady hyperthermia provide correlations between these parameters and the portions of tumor and healthy tissue that are subjected to a threshold temperature beyond which they are damaged. Increasing the ratio of the Fourier and Joule numbers also increases the tumor temperature, but doing so can damage the healthy tissue. Higher magnetic heating is required for larger Peclet numbers due to the larger convection heat loss that occurs through blood perfusion. A comparison of the model predictions with previous experimental data for MFH applied to rabbit tumors shows good agreement. The optimal MFH conditions are identified based on two indices, the fraction I{sub T} of the tumor volume in which the local temperature is above a threshold temperature and the ratio I{sub N} of the damaged normal tissue volume to the tumor tissue volume that also lies above it. The spatial variation in the nanoparticle concentration is also considered. A Gaussian distribution provides efficacy while minimizing the possibility of generating a tumor hot spot. Varying the thermal properties of tumor and normal tissue alters I{sub T}and I{sub N} but the nature of the temperature distribution remains unchanged. - Research highlights: > Analytical model of magnetic fluid hyperthermia of tumor tissue perfused with magnetic nanoparticles that is surrounded

  3. [Evaluation of the blood flow in common hepatic tumors by multi-slice spiral CT whole-liver perfusion imaging].

    Science.gov (United States)

    Li, Mengdi; Chen, Yong; Gao, Zhiling; Zhu, Kai; Yin, Xin

    2015-12-01

    To study the characteristics of blood flow in common hepatic tumors by 256-slice spiral CT whole-liver perfusion imaging. Seventy-one patients with hepatic tumors were examined retrospectively by 256-slice spiral CT whole-liver perfusion. Among them, twenty-seven cases were of primary hepatic cancer, twenty-four cases of hepatic hemangioma, and twenty cases of hepatic metastases.Regions of interest (ROIs) were placed in the tumor parenchyma (Area A), peritumoral hepatic parenchyma (Area B), and normal hepatic parenchyma (Area C), respectively. The time density curves (TDC) were drawn, and perfusion parameters including hepatic arterial perfusion(HAP), portal venous perfusion(PVP), total liver perfusion(TLP) and hepatic erfusion index(HPI) were obtained. The values of ROIs were measured, and the perfusion parameters in the areas A, B, C of different hepatic tumors were statistically analyzed. The values of HAP, PVP, HPI in the tumor parenchyma of primary hepatic carcinoma were (20.00 ± 11.41)ml · min(-1) · 100 ml(-1,) (32.31 ± 21.06)ml · min(-1) · 100 ml(-1,) (52.31 ± 30.55)ml · min(-1) · 100 ml(-1,) and (39.67 ± 11.19)%, showing significant difference as compared with those in peritumoral hepatic parenchyma and in normal hepatic parenchyma(PHAP, TLP, and HPI in the tumor parenchyma of hepatic hemangioma were (40.39 ± 29.23)ml · min(-1) · 100 ml(-1,) (132.72 ± 132.65) ml · min(-1) · 100 ml(-1,) and (35.51 ± 15.12)%, were significantly different as compared with those in the peritumoral hepatic parenchyma and in normal hepatic parenchyma(PHAP, PVP, HPI in the tumor parenchyma of hepatic metastases were (17.43 ± 12.27)ml · min(-1) · 100 ml(-1,) (36.19 ± 34.99) ml · min(-1) · 100 ml(-1,) and (37.86 ± 14.49)%, significantly different as compared normal hepatic parenchyma (PHAP, PVP, and TLP of tumor tissue and the PVP and HPI of peritumoral tissue in different hepatic tumors were statistically significantly different (P<0.05). The multi

  4. CT perfusion during delayed cerebral ischemia after subarachnoid hemorrhage: distinction between reversible ischemia and ischemia progressing to infarction

    Energy Technology Data Exchange (ETDEWEB)

    Cremers, Charlotte H.P. [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, PO Box 85500, Utrecht, Utrecht (Netherlands); University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Vos, Pieter C. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Schaaf, Irene C. van der; Velthuis, Birgitta K.; Dankbaar, Jan Willem [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Vergouwen, Mervyn D.I.; Rinkel, Gabriel J.E. [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, PO Box 85500, Utrecht, Utrecht (Netherlands)

    2015-09-15

    Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) can be reversible or progress to cerebral infarction. In patients with a deterioration clinically diagnosed as DCI, we investigated whether CT perfusion (CTP) can distinguish between reversible ischemia and ischemia progressing to cerebral infarction. From a prospectively collected series of aSAH patients, we included those with DCI, CTP on the day of clinical deterioration, and follow-up imaging. In qualitative CTP analyses (visual assessment), we calculated positive and negative predictive value (PPV and NPV) with 95 % confidence intervals (95%CI) of a perfusion deficit for infarction on follow-up imaging. In quantitative analyses, we compared perfusion values of the least perfused brain tissue between patients with and without infarction by using receiver-operator characteristic curves and calculated a threshold value with PPV and NPV for the perfusion parameter with the highest area under the curve. In qualitative analyses of 33 included patients, 15 of 17 patients (88 %) with and 6 of 16 patients (38 %) without infarction on follow-up imaging had a perfusion deficit during clinical deterioration (p = 0.002). Presence of a perfusion deficit had a PPV of 71 % (95%CI: 48-89 %) and NPV of 83 % (95%CI: 52-98 %) for infarction on follow-up. Quantitative analyses showed that an absolute minimal cerebral blood flow (CBF) threshold of 17.7 mL/100 g/min had a PPV of 63 % (95%CI: 41-81 %) and a NPV of 78 % (95%CI: 40-97 %) for infarction. CTP may differ between patients with DCI who develop infarction and those who do not. For this purpose, qualitative evaluation may perform marginally better than quantitative evaluation. (orig.)

  5. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  6. The association between inadequate prenatal care and future healthcare use among offspring in the Bedouin population.

    Science.gov (United States)

    Estis-Deaton, Asia; Sheiner, Eyal; Wainstock, Tamar; Landau, Daniella; Walfisch, Asnat

    2017-12-01

    To evaluate the impact of inadequate prenatal care on long-term morbidity among the offspring of an ethnic minority population. A retrospective population-based cohort analysis was performed among all Bedouin women with singleton pregnancies who delivered in a tertiary medical center in Israel between January 1, 1991, and January 1, 2014. Morbidity was defined as pediatric hospitalization across six distinct disease categories before 18 years of age. The cumulative morbidity rates were compared for offspring born following pregnancies with either inadequate (prenatal care facility) or adequate prenatal care. Overall, 127 396 neonates were included; 19 173 (15.0%) were born following inadequate prenatal care. Pediatric hospitalizations for all morbidities other than cardiovascular ones were less frequent among the inadequate prenatal care group than the adequate prenatal care group (Pprenatal care group, with the exception of cardiovascular disease. Inadequate prenatal care correlated with reduced pediatric hospitalization rates among offspring, possibly owing to a lack of child healthcare service utilization within the Bedouin population. © 2017 International Federation of Gynecology and Obstetrics.

  7. Consequences of Inadequate Staffing Include Missed Care, Potential Failure to Rescue, and Job Stress and Dissatisfaction.

    Science.gov (United States)

    Simpson, Kathleen Rice; Lyndon, Audrey; Ruhl, Catherine

    2016-01-01

    To evaluate responses of registered nurse members of the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN) to a survey that sought their recommendations for staffing guidelines and their perceptions of the consequences of inadequate nurse staffing. The goal was to use these member data to inform the work of the AWHONN nurse staffing research team. Secondary analysis of responses to the 2010 AWHONN nurse staffing survey. Online. AWHONN members (N = 884). Review of data from an online survey of AWHONN members through the use of thematic analysis for descriptions of the consequences of inadequate nurse staffing during the childbirth process. Three main themes emerged as consequences of inadequate staffing or being short-staffed: Missed Care, Potential for Failure to Rescue, and Job-Related Stress and Dissatisfaction. These themes are consistent with those previously identified in the literature related to inadequate nurse staffing. Based on the responses from participants in the 2010 AWHONN nurse staffing survey, consequences of inadequate staffing can be quite serious and may put patients at risk for preventable harm. Copyright © 2016 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  8. Spatiotemporal dynamics of cortical perfusion in response to thalamic deep brain stimulation.

    Science.gov (United States)

    Noor, M Sohail; Murari, Kartikeya; McCracken, Clinton B; Kiss, Zelma H T

    2016-02-01

    Deep brain stimulation (DBS) has revolutionized the treatment of movement disorders. The parameters of electrical stimulation are important to its therapeutic effect and remain a source of clinical controversy. DBS exerts its actions not only locally at the site of stimulation but also remotely through afferent and efferent connections, which are vital to its clinical effects. Yet, only a few studies have examined how cortical activity changes in response to various electrical parameters. Here, we investigated how the parameters of thalamic DBS alter cortical perfusion in rats using intrinsic optical imaging. We hypothesized that thalamic DBS will increase perfusion in primary motor cortex (M1), proportional to amplitude, pulse width, or frequency of the stimulation applied. We applied 45 different combinations of amplitude, pulse width and frequency in the ventro-lateral (VL) nucleus of the thalamus in anesthetized rats while measuring perfusion in M1. VL thalamic DBS reduced cortical reflectance, which corresponds to an increase in cortical perfusion. We computed the maximum change in reflectance (MCR) as well as the spatial spread of MCR in each trial. Both MCR and spatial spread increased linearly with increases in current amplitude or pulse width of stimulation; however, the effect of frequency was non-linear. Stimulation at 20 Hz was significantly different from that at higher frequencies while stimulation at higher frequencies did not differ significantly from each other. Moreover, the effect of pulse width on MCR was larger than the effect of amplitude. The proportional increase in M1 perfusion due to increase in amplitude or pulse width suggests that both activate more neural elements and increase the volume of tissue activated. These results should help clinicians set parameters of DBS. The use of optical imaging to monitor effects of DBS on M1 may not only help understand DBS mechanisms, but may also provide feedback for closed loop DBS devices

  9. C-arm cone beam CT perfusion imaging using the SMART-RECON algorithm to improve temporal sampling density and temporal resolution

    Science.gov (United States)

    Li, Yinsheng; Niu, Kai; Li, Ke; Schafer, Sebastian; Royalty, Kevin; Strother, Charles; Chen, Guang-Hong

    2016-03-01

    In this work, a newly developed reconstruction algorithm, Synchronized MultiArtifact Reduction with Tomographic RECONstruction (SMART-RECON), was applied to C-arm cone beam CT perfusion (CBCTP) imaging. This algorithm contains a special rank regularizer, designed to reduce limited-view artifacts associated with super- short scan reconstructions. As a result, high temporal sampling and temporal resolution image reconstructions were achieved using an interventional C-arm x-ray system. The algorithm was evaluated in terms of the fidelity of the dynamic contrast update curves and the accuracy of perfusion parameters through numerical simulation studies. Results shows that, not only were the dynamic curves accurately recovered (relative root mean square error ∈ [3%, 5%] compared with [13%, 22%] for FBP), but also the noise in the final perfusion maps was dramatically reduced. Compared with filtered backprojection, SMART-RECON generated CBCTP maps with much improved capability in differentiating lesions with perfusion deficits from the surrounding healthy brain tissues.

  10. Fast Doppler as a novel bedside measure of cerebral perfusion in preterm infants.

    Science.gov (United States)

    Peeples, Eric S; Mehic, Edin; Mourad, Pierre D; Juul, Sandra E

    2016-02-01

    Altered cerebral perfusion from impaired autoregulation may contribute to the morbidity and mortality associated with premature birth. We hypothesized that fast Doppler imaging could provide a reproducible bedside estimation of cerebral perfusion and autoregulation in preterm infants. This is a prospective pilot study using fast Doppler ultrasound to assess blood flow velocity in the basal ganglia of 19 subjects born at 26-32 wk gestation. Intraclass correlation provided a measure of test-retest reliability, and linear regression of cerebral blood flow velocity and heart rate or blood pressure allowed for estimations of autoregulatory ability. The intraclass correlation when imaging in the first 48 h of life was 0.634. We found significant and independent correlations between the systolic blood flow velocity and both systolic blood pressure and heart rate (P = 0.015 and 0.012 respectively) only in the 26-28 wk gestational age infants in the first 48 h of life. Our results suggest that fast Doppler provides reliable bedside measurements of cerebral blood flow velocity at the tissue level in premature infants, acting as a proxy for cerebral tissue perfusion. Additionally, autoregulation appears to be impaired in the extremely preterm infants, even within a normal range of blood pressures.

  11. Repeatability of Cerebral Perfusion Using Dynamic Susceptibility Contrast MRI in Glioblastoma Patients.

    Science.gov (United States)

    Jafari-Khouzani, Kourosh; Emblem, Kyrre E; Kalpathy-Cramer, Jayashree; Bjørnerud, Atle; Vangel, Mark G; Gerstner, Elizabeth R; Schmainda, Kathleen M; Paynabar, Kamran; Wu, Ona; Wen, Patrick Y; Batchelor, Tracy; Rosen, Bruce; Stufflebeam, Steven M

    2015-06-01

    This study evaluates the repeatability of brain perfusion using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with a variety of post-processing methods. Thirty-two patients with newly diagnosed glioblastoma were recruited. On a 3-T MRI using a dual-echo, gradient-echo spin-echo DSC-MRI protocol, the patients were scanned twice 1 to 5 days apart. Perfusion maps including cerebral blood volume (CBV) and cerebral blood flow (CBF) were generated using two contrast agent leakage correction methods, along with testing normalization to reference tissue, and application of arterial input function (AIF). Repeatability of CBV and CBF within tumor regions and healthy tissues, identified by structural images, was assessed with intra-class correlation coefficients (ICCs) and repeatability coefficients (RCs). Coefficients of variation (CVs) were reported for selected methods. CBV and CBF were highly repeatable within tumor with ICC values up to 0.97. However, both CBV and CBF showed lower ICCs for healthy cortical tissues (up to 0.83), healthy gray matter (up to 0.95), and healthy white matter (WM; up to 0.93). The values of CV ranged from 6% to 10% in tumor and 3% to 11% in healthy tissues. The values of RC relative to the mean value of measurement within healthy WM ranged from 22% to 42% in tumor and 7% to 43% in healthy tissues. These percentages show how much variation in perfusion parameter, relative to that in healthy WM, we expect to observe to consider it statistically significant. We also found that normalization improved repeatability, but AIF deconvolution did not. DSC-MRI is highly repeatable in high-grade glioma patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Repeatability of Cerebral Perfusion Using Dynamic Susceptibility Contrast MRI in Glioblastoma Patients12

    Science.gov (United States)

    Jafari-Khouzani, Kourosh; Emblem, Kyrre E.; Kalpathy-Cramer, Jayashree; Bjørnerud, Atle; Vangel, Mark G.; Gerstner, Elizabeth R.; Schmainda, Kathleen M.; Paynabar, Kamran; Wu, Ona; Wen, Patrick Y.; Batchelor, Tracy; Rosen, Bruce; Stufflebeam, Steven M.

    2015-01-01

    OBJECTIVES This study evaluates the repeatability of brain perfusion using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with a variety of post-processing methods. METHODS Thirty-two patients with newly diagnosed glioblastoma were recruited. On a 3-T MRI using a dual-echo, gradient-echo spin-echo DSC-MRI protocol, the patients were scanned twice 1 to 5 days apart. Perfusion maps including cerebral blood volume (CBV) and cerebral blood flow (CBF) were generated using two contrast agent leakage correction methods, along with testing normalization to reference tissue, and application of arterial input function (AIF). Repeatability of CBV and CBF within tumor regions and healthy tissues, identified by structural images, was assessed with intra-class correlation coefficients (ICCs) and repeatability coefficients (RCs). Coefficients of variation (CVs) were reported for selected methods. RESULTS CBV and CBF were highly repeatable within tumor with ICC values up to 0.97. However, both CBV and CBF showed lower ICCs for healthy cortical tissues (up to 0.83), healthy gray matter (up to 0.95), and healthy white matter (WM; up to 0.93). The values of CV ranged from 6% to 10% in tumor and 3% to 11% in healthy tissues. The values of RC relative to the mean value of measurement within healthy WM ranged from 22% to 42% in tumor and 7% to 43% in healthy tissues. These percentages show how much variation in perfusion parameter, relative to that in healthy WM, we expect to observe to consider it statistically significant. We also found that normalization improved repeatability, but AIF deconvolution did not. CONCLUSIONS DSC-MRI is highly repeatable in high-grade glioma patients. PMID:26055170

  13. Comparison between acoustic radiation force impulse quantification data and perfusion-CT parameters in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Esser, Michael, E-mail: michael.esser@med.uni-tuebingen.de; Schneeweiß, Sven, E-mail: sven.schneeweiss@med.uni-tuebingen.de; Kolb, Manuel, E-mail: manuel.kolb@med.uni-tuebingen.de; Kurucay, Mustafa, E-mail: mustafa.kurucay@med.uni-tuebingen.de; Ruff, Christer, E-mail: christer.ruff@med.uni-tuebingen.de; Nikolaou, Konstantin, E-mail: konstantin.nikolaou@med.uni-tuebingen.de; Horger, Marius, E-mail: marius.horger@med.uni-tuebingen.de

    2017-04-15

    Highlights: • HCC tissue stiffness did not correlate with the degree of tumor vascularization. • HCC tissue stiffness declined while increasing HCC distance to the skin surface. • HCC tissue stiffness showed higher values the larger the respective tumor was. • Poorly differentiated HCCs showed increased values of tumor tissue stiffness. - Abstract: Objective: To find out, if ultrasound elastography of hepatocellular carcinoma (HCC) can predict patterns of tumor perfusion in volume perfusion computed tomography (VPCT). Material and methods: 25 consecutive patients (mean age, 68.9; range, 51–85 years) with liver cirrhosis suspected of HCC underwent VPCT and acoustic radiation force impulse (ARFI) elastography the same day. Quantitative elasticity values were registered, while blood flow (BF), blood volume (BV) and hepatic perfusion index (HPI) of the HCC lesions were calculated. Additionally, we identified histologic WHO grading, lesion size and localization. The Siemens Acuson S 3000 HELX-System with Virtual Touch™-Software and Siemens Somatom Definition Flash with Syngo{sup ®} software were used. Results: A total of 43 HCC lesions were assessed. Mean shear wave velocity was 2.6 m/s (range, 1.1–4.3 m/s). There was no significant linear correlation between the elasticity values and BF (p = 0.751), BV (p = 0.426) and HPI (p = 0.437). However, elasticity values were higher, the larger the tumor was (p = 0.008). Shear wave velocity declined with increasing distance of the HCC to the skin surface (p = 0.028) and depending on liver segment. In addition, elasticity values were higher in less differentiated HCCs. This trend was not statistically significant (p = 0.842). Conclusion: Tissue elasticity in HCC does not correlate with the degree of tumor vascularization, but calculated values are influenced both by the tumor size and localization inside the liver.

  14. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Y.; Hayashida, K.; Uehara, T.; Shimonagata, T.; Nishimura, T.; Osaka Univ., Suita

    1993-01-01

    15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 ± 10 mmHg) was higher than in those with a normal pattern (42 ± 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. (author)

  15. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Yoji; Nishimura, Tsunehiko; Kumita, Shin-ichirou; Hayashida, Kohei; Uehara, Toshiisa; Shimonagata, Tsuyoshi; Ohno, Akira

    1991-01-01

    Fifteen cases with primary pulmonary hypertension (PPH) were classified into two groups by using the perfusion lung scan pattern. Eight cases had multiple, small, ill-defined defects (mottled pattern), and remaining seven cases had no mottled pattern. These two groups were compared with mean pulmonary arterial pressure (mean PAP), right ventricular ejection fraction (RVEF), blood gas at room air (PaO 2 ), and alveolar-arterial O 2 difference (A-aDo 2 ). The cases with mottled pattern showed a significant increase in mean PAP. There were no significant differences in RVEF, PaO 2 , and A-aDo 2 , between the groups. The survival rate of the patients with mottled pattern was significantly lower than that without mottled pattern (p<0.05). We concluded that perfusion lung scan is very useful for evaluation of the prognosis in primary pulmonary hypertension. (author)

  16. Quantitative aspects of myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1980-01-01

    Myocardial perfusion measurements have traditionally been performed in a quantitative fashion using application of the Sapirstein, Fick, Kety-Schmidt, or compartmental analysis principles. Although global myocardial blood flow measurements have not proven clinically useful, regional determinations have substantially advanced our understanding of and ability to detect myocardial ischemia. With the introduction of thallium-201, such studies have become widely available, although these have generally undergone qualitative evaluation. Using computer-digitized data, several methods for the quantification of myocardial perfusion images have been introduced. These include orthogonal and polar coordinate systems and anatomically oriented region of interest segmentation. Statistical ranges of normal and time-activity analyses have been applied to these data, resulting in objective and reproducible means of data evaluation

  17. Captopril improves tumor nanomedicine delivery by increasing tumor blood perfusion and enlarging endothelial gaps in tumor blood vessels.

    Science.gov (United States)

    Zhang, Bo; Jiang, Ting; Tuo, Yanyan; Jin, Kai; Luo, Zimiao; Shi, Wei; Mei, Heng; Hu, Yu; Pang, Zhiqing; Jiang, Xinguo

    2017-12-01

    Poor tumor perfusion and unfavorable vessel permeability compromise nanomedicine drug delivery to tumors. Captopril dilates blood vessels, reducing blood pressure clinically and bradykinin, as the downstream signaling moiety of captopril, is capable of dilating blood vessels and effectively increasing vessel permeability. The hypothesis behind this study was that captopril can dilate tumor blood vessels, improving tumor perfusion and simultaneously enlarge the endothelial gaps of tumor vessels, therefore enhancing nanomedicine drug delivery for tumor therapy. Using the U87 tumor xenograft with abundant blood vessels as the tumor model, tumor perfusion experiments were carried out using laser Doppler imaging and lectin-labeling experiments. A single treatment of captopril at a dose of 100 mg/kg significantly increased the percentage of functional vessels in tumor tissues and improved tumor blood perfusion. Scanning electron microscopy of tumor vessels also indicated that the endothelial gaps of tumor vessels were enlarged after captopril treatment. Immunofluorescence-staining of tumor slices demonstrated that captopril significantly increased bradykinin expression, possibly explaining tumor perfusion improvements and endothelial gap enlargement. Additionally, imaging in vivo, imaging ex vivo and nanoparticle distribution in tumor slices indicated that after a single treatment with captopril, the accumulation of 115-nm nanoparticles in tumors had increased 2.81-fold with a more homogeneous distribution pattern in comparison to non-captopril treated controls. Finally, pharmacodynamics experiments demonstrated that captopril combined with paclitaxel-loaded nanoparticles resulted in the greatest tumor shrinkage and the most extensive necrosis in tumor tissues among all treatment groups. Taken together, the data from the present study suggest a novel strategy for improving tumor perfusion and enlarging blood vessel permeability simultaneously in order to improve

  18. Diffusion and Perfusion Characteristics of MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episode) in Thirteen Patients

    International Nuclear Information System (INIS)

    Kim, Ji Hye; Jeon, Tae Yeon; Eo, Hong; Yoo, So Young; Lim, Myung Kwan; Rha, Jung Ho; Shu, Chang Hae

    2011-01-01

    We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 ± 40.9% in the MELAS and 64 ± 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage

  19. Measurement of ventilation- and perfusion-mediated cooling during laser ablation in ex vivo human lung tumors.

    Science.gov (United States)

    Vietze, Andrea; Koch, Franziska; Laskowski, Ulrich; Linder, Albert; Hosten, Norbert

    2011-11-01

    Perfusion-mediated tissue cooling has often been described in the literature for thermal ablation therapies of liver tumors. The objective of this study was to investigate the cooling effects of both perfusion and ventilation during laser ablation of lung malignancies. An ex vivo lung model was used to maintain near physiological conditions for the specimens. Fourteen human lung lobes containing only primary lung tumors (non-small cell lung cancer) were used. Laser ablation was carried out using a Nd:YAG laser with a wavelength of 1064 nm and laser fibers with 30 mm diffusing tips. Continuous invasive temperature measurement in 10 mm distance from the laser fiber was performed. Laser power was increased at 2 W increments starting at 10 W up to a maximum power of 12-20 W until a temperature plateau around 60 °C was reached at one sensor. Ventilation and perfusion were discontinued for 6 min each to assess their effects on temperature development. The experiments lead to 25 usable temperature profiles. A significant temperature increase was observed for both discontinued ventilation and perfusion. In 6 min without perfusion, the temperature rose about 5.5 °C (mean value, Pcooling are significant influencing factors on temperature development during thermal ablation. They should be taken into account during the planning and preparation of minimally invasive lung tumor treatment in order to achieve complete ablation. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Non-contrast MRI perfusion angiosome in diabetic feet

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

    2015-01-15

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  1. Dynamic CT perfusion measurement in a cardiac phantom.

    Science.gov (United States)

    Ziemer, Benjamin P; Hubbard, Logan; Lipinski, Jerry; Molloi, Sabee

    2015-10-01

    Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques.

  2. [Value of perfusion scintigraphy of the testis].

    Science.gov (United States)

    Kotzerke, J; Erpenbach, K; Hengst, W

    1987-10-01

    Perfusion scintigraphy of the testicles has still its place, in addition to scrotal ultrasound imaging, in the investigation of the "acute scrotum". It reveals scintigraphic patterns typical for twisted testicle and acute or subacute epididymitis. Especially in the Bundeswehr, with its large number of young men, this method enhances the diagnostic spectrum and helps in making surgical decisions. However, in the examination of scrotal masses, ultrasound imaging or surgery is to be preferred.

  3. The evolution of perfusion education in America.

    Science.gov (United States)

    Toomasian, John M; Searles, Bruce; Kurusz, Mark

    2003-07-01

    Clinical cardiopulmonary perfusion has evolved significantly during its 50 years. The science, technology and educational processes related to cardiopulmonary bypass have undergone continual change and metamorphosis. Perfusionists were initially trained on the job or in the laboratory, but with the advent of myocardial revascularization and the explosion in cardiac surgery, the need for formal educational training programs became apparent. The American Society of Extracorporeal Technology began the arduous processes of credentialing and developing certification guidelines that have continued under the American Board of Cardiovascular Perfusion. Licensure has also been adopted in many states during the past 10 years where nearly 50% of all perfusionists are covered by some legislative act. One additonal challenge has been developing minimal standards in which perfusionists practice. The initial standards included the use of a checklist and have evolved to monitoring and recording the significant events and parameters of each clinical procedure. The education of perfusionists will continue to be a challenge related primarily to reduced fiscal resources, the applicant pool and the ever-changing demands for extracorporeal circulation services. According to demographic and census information, it is expected the overall number of cardiovascular interventions will increase dramatically towards the latter end of the current decade in the US. The question arises as to what role perfusionists will play, as treatment strategies continue to change. If the number of education programs and new graduates continue to decline, the total number of perfusionists will decline, especially as many senior perfusionists leave the field or retire. It may be difficult to predict the total number of cardiovascular interventions that will be required in the next several years. However, if the total number of cardiovascular interventions that require perfusion services increase as a function

  4. Myocardial perfusion studies in coronary diseases

    International Nuclear Information System (INIS)

    Mut, Fernando

    1994-01-01

    For detecting in precocious form a coronary disease is necessary to apply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images,proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases

  5. Regional cerebral perfusion in cardiovascular reflex syncope

    International Nuclear Information System (INIS)

    Toeyry, J.P.; Kuikka, J.T.; Laensimies, E.A.

    1997-01-01

    Little is known about the regional cerebral perfusion in subjects with presyncope or syncope, and the impact that autonomic nervous dysfunction has on it. Seven subjects with cardiovascular vasodepressor reflex syncope were studied. A baseline test was performed with the patients standing in the 70 upright position, while the passive head-up tilt table test with and without isoprenaline infusion was employed for provocation. Regional cerebral perfusion was assessed by means of single-photon emission tomography with technetium-99m labelled V-oxo-1,2-N,N 1 -ethylenedylbis-l-cysteine diethylester (baseline, and during blood pressure decline in the provocation test) and the autonomic nervous function by means of spectral analysis of heart rate variability (baseline, and before blood pressure decline in the provocation test). Every subject showed an abrupt decline in blood pressure in the provocation test (five with presyncope and two with syncope). The systolic and diastolic blood pressures decreased significantly (P<0.001) between the baseline and the provocation study time points (radiopharmaceutical injection and lowest systolic blood pressure). Mean cerebral perfusion as average count densities decreased upon provocation as compared with baseline (190±63 vs 307±90 counts/voxel, respectively, P=0.013). Hypoperfusion was most pronounced in the frontal lobe. These results suggest that cerebral perfusion decreases markedly during presyncope or syncope with systemic blood pressure decline in subjects with cardiovascular vasodepressor syncope. Furthermore, the autonomic nervous function remains unchanged before the systemic blood pressure decline. (orig.). With 3 figs., 2 tabs

  6. Application of dynamic indocyanine green perfusion imaging for evaluation of vasoactive effect of acupuncture: a preliminary follow-up study on normal healthy volunteers

    Directory of Open Access Journals (Sweden)

    An Y

    2014-02-01

    Full Text Available Yuri An,1 Jong Wook Jeon,2 Kihwan Kwon,3 Chulhee Choi1 1Department of Bio and Brain Engineering, KAIST, Daejeon, South Korea; 2Acupuncture, Moxibustion and Meridian Research Centre, Korea Institute of Oriental Medicine, Daejeon, South Korea; 3Department of Cardiology, College of Medicine, Ewha Womans University, Seoul, Korea Background: Even though acupuncture has long been used for alleviating symptoms related to vascular insufficiency, the clinical effect of acupuncture on peripheral circulation has not been fully confirmed. In this study, we investigated whether a near-infrared optical imaging-based method can be used to evaluate the efficacy of the acupuncture procedure to induce changes in peripheral tissue perfusion. Methods: Two normal, healthy controls were treated with acupuncture on two acupoints (LI-4 and SI-3 three times within 1 week. At the first and third visits, participants were examined using indocyanine green (ICG perfusion imaging before and 10 minutes after the acupuncture procedure. Blood perfusion of the hands was determined after intravenous bolus injection of ICG and dynamic analysis of the fluorescence signals by near-infrared imaging system. Results: The blood perfusion rates of the hands were markedly increased immediately after acupuncture at the first trial in both cases. The baseline perfusion rates of the hands measured at the third visit were higher compared to the original basal level in one case; there was no difference in baseline perfusion rates of both hands in another case. In both cases, there was no acute effect of acupuncture on hand perfusion at the third trial. Conclusions: These results collectively suggest a potential of the ICG perfusion imaging as an effective evaluation tool to validate the vasoactive effect of acupuncture. Keywords: vasodilation, blood perfusion, imaging, Raynaud syndrome

  7. Quantification of right ventricular function in acute pulmonary embolism: relation to extent of pulmonary perfusion defects

    DEFF Research Database (Denmark)

    Kjaergaard, J.; Schaadt, B.K.; Lund, J.O.

    2008-01-01

    and global and regional performance. Intermediate and large pulmonary emboli were associated with a significant impact on RV pressure and function. For small pulmonary emboli obstructing ...Aims The relation of the extent of obstruction of the pulmonary vascutature in pulmonary embolism (PE) and impact on right ventricular (RV) hemodynamics is not well established. This study evaluated the relation of size of perfusion defects and changes in echocardiographic measures of global...... and regional RV dysfunction in 58 consecutive patients with non-massive PE. Methods and results Patients were compared with 58 age-matched controls that had normal ventilation/perfusion scintigraphies. A 2D, Doppler and Tissue Doppler echocardiography performed on the same day, quantified RV pressure...

  8. [Effect of glucocorticoides on the release of amino acids in the perfused rat hindquarter (author's transl)].

    Science.gov (United States)

    Thienhaus, R; Tharandt, L; Zais, U; Staib, W

    1975-06-01

    The release of amino acids by skeletal muscle was studied in the isolated perfused rat hindquarter. Adrenalectomy depressed the formation of glutamine and alanine as well as the efflux of all other amino acids measured. Betamethasone--a synthetic glucocorticoid--caused a significant increase in the efflux of nearly all amino acids up to the level of normal controls. The release of amino acids was also increased in perfused hindquarters of diabetic rats. On the other hand, insulin exhibited a depressing effect on the release of amino acids by hindquarters of normal rats. The metabolic integrity of the muscle tissue was proved by measuring creatine phosphate, ATP, ADP and water content as well as by the significant insulin effect on glucose uptake and on [14C]leucine incorporation into muscle proteins.

  9. Quantification of right ventricular function in acute pulmonary embolism: relation to extent of pulmonary perfusion defects

    DEFF Research Database (Denmark)

    Kjaergaard, J.; Schaadt, B.K.; Lund, J.O.

    2008-01-01

    Aims The relation of the extent of obstruction of the pulmonary vascutature in pulmonary embolism (PE) and impact on right ventricular (RV) hemodynamics is not well established. This study evaluated the relation of size of perfusion defects and changes in echocardiographic measures of global...... and regional RV dysfunction in 58 consecutive patients with non-massive PE. Methods and results Patients were compared with 58 age-matched controls that had normal ventilation/perfusion scintigraphies. A 2D, Doppler and Tissue Doppler echocardiography performed on the same day, quantified RV pressure...... and global and regional performance. Intermediate and large pulmonary emboli were associated with a significant impact on RV pressure and function. For small pulmonary emboli obstructing

  10. Flow perfusion culture of human mesenchymal stem cells on coralline hydroxyapatite scaffolds with various pore sizes

    DEFF Research Database (Denmark)

    Bjerre, Lea; Bünger, Cody; Baatrup, Anette

    2011-01-01

    Bone grafts are widely used in orthopaedic reconstructive surgery, but harvesting of autologous grafts is limited due to donor site complications. Bone tissue engineering is a possible alternative source for substitutes, and to date, mainly small scaffold sizes have been evaluated. The aim...... of this study was to obtain a clinically relevant substitute size using a direct perfusion culture system. Human bone marrowderived mesenchymal stem cells were seeded on coralline hydroxyapatite scaffolds with 200 μm or 500 μm pores, and resulting constructs were cultured in a perfusion bioreactor or in static...... number of cells was higher in 500 μm constructs as compared with 200 μm constructs. Alkaline phosphatase enzyme activity assays and real time RT-PCR on seven osteogenic markers showed that differentiation occurred primarily and earlier in statically cultured constructs with 200 μm pores compared with 500...

  11. Comparison of stroke infarction between CT perfusion and diffusion weighted imaging: preliminary results

    Science.gov (United States)

    Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh

    2016-03-01

    In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.

  12. Prolonged preservation of the blood-perfused canine heart with glycolysis-promoting solution.

    Science.gov (United States)

    Takeuchi, K; Cao-Danh, H; Kawai, A; Ohkado, A; Konishi, H; McGowan, F X; del Nido, P J

    1999-09-01

    Prolonged ischemia and inadequate myocardial preservation remain significant perioperative risk factors in cardiac transplantation. Long-term preservation techniques that have been effective in small rodent hearts have not been as effective in larger animal models or in clinical studies. We developed a cardioplegia solution formulated to promote high-energy phosphate production from glycolysis and determined its efficacy in a blood perfused canine heart model subjected to 24 hours of ischemia. Hearts harvested from adult dogs (n = 6 per group) were flushed with a histidine-buffered cardioplegia solution containing glucose or University of Wisconsin solution. The hearts were maintained at 4 degrees C for 24 hours then reperfused with autologous blood. After reperfusion, left ventricular pressures were measured with an intracavitary balloon at varying balloon volumes and compared with control nonischemic hearts. Predicted stroke volume and ejection fraction were calculated at an end-systolic pressure of 70 mm Hg and end-diastolic pressure of 15 mm Hg. Developed pressure was better preserved in the hearts that received histidine-buffered solution (93+/-9 versus 38+/-7 mm Hg, pglycolysis-promoting cardioplegia solution provided effective preservation of the blood perfused canine heart with superior recovery of pump performance after 24 hours of hypothermic ischemia compared with University of Wisconsin solution in this model.

  13. A simultaneous multimodal imaging system for tissue functional parameters

    Science.gov (United States)

    Ren, Wenqi; Zhang, Zhiwu; Wu, Qiang; Zhang, Shiwu; Xu, Ronald

    2014-02-01

    Simultaneous and quantitative assessment of skin functional characteristics in different modalities will facilitate diagnosis and therapy in many clinical applications such as wound healing. However, many existing clinical practices and multimodal imaging systems are subjective, qualitative, sequential for multimodal data collection, and need co-registration between different modalities. To overcome these limitations, we developed a multimodal imaging system for quantitative, non-invasive, and simultaneous imaging of cutaneous tissue oxygenation and blood perfusion parameters. The imaging system integrated multispectral and laser speckle imaging technologies into one experimental setup. A Labview interface was developed for equipment control, synchronization, and image acquisition. Advanced algorithms based on a wide gap second derivative reflectometry and laser speckle contrast analysis (LASCA) were developed for accurate reconstruction of tissue oxygenation and blood perfusion respectively. Quantitative calibration experiments and a new style of skinsimulating phantom were designed to verify the accuracy and reliability of the imaging system. The experimental results were compared with a Moor tissue oxygenation and perfusion monitor. For In vivo testing, a post-occlusion reactive hyperemia (PORH) procedure in human subject and an ongoing wound healing monitoring experiment using dorsal skinfold chamber models were conducted to validate the usability of our system for dynamic detection of oxygenation and perfusion parameters. In this study, we have not only setup an advanced multimodal imaging system for cutaneous tissue oxygenation and perfusion parameters but also elucidated its potential for wound healing assessment in clinical practice.

  14. Probabilistic pharmacokinetic models of decompression sickness in humans, part 1: Coupled perfusion-limited compartments.

    Science.gov (United States)

    Murphy, F Gregory; Hada, Ethan A; Doolette, David J; Howle, Laurens E

    2017-07-01

    Decompression sickness (DCS) is a disease caused by gas bubbles forming in body tissues following a reduction in ambient pressure, such as occurs in scuba diving. Probabilistic models for quantifying the risk of DCS are typically composed of a collection of independent, perfusion-limited theoretical tissue compartments which describe gas content or bubble volume within these compartments. It has been previously shown that 'pharmacokinetic' gas content models, with compartments coupled in series, show promise as predictors of the incidence of DCS. The mechanism of coupling can be through perfusion or diffusion. This work examines the application of five novel pharmacokinetic structures with compartments coupled by perfusion to the prediction of the probability and time of onset of DCS in humans. We optimize these models against a training set of human dive trial data consisting of 4335 exposures with 223 DCS cases. Further, we examine the extrapolation quality of the models on an additional set of human dive trial data consisting of 3140 exposures with 147 DCS cases. We find that pharmacokinetic models describe the incidence of DCS for single air bounce dives better than a single-compartment, perfusion-limited model. We further find the U.S. Navy LEM-NMRI98 is a better predictor of DCS risk for the entire training set than any of our pharmacokinetic models. However, one of the pharmacokinetic models we consider, the CS2T3 model, is a better predictor of DCS risk for single air bounce dives and oxygen decompression dives. Additionally, we find that LEM-NMRI98 outperforms CS2T3 on the extrapolation data. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Abnormalities of Microcirculation and Intracranial and Cerebral Perfusion Pressures in Severe Brain Injury

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2008-01-01

    Full Text Available Objective: to evaluate the states of microcirculation, cerebral perfusion intracranial pressures in patients with isolated severe brain injury (SBI and to determine their possible relationships. Subjects and methods. 148 studies were performed in 16 victims with SBI. According to the outcome of brain traumatic disease, the patients were divided into two groups: 1 those who had a good outcome (n=8 and 2 those who had a fatal outcome (n=8. Microcirculation was examined by skin laser Doppler flowmetry using a LAKK-01 capillary blood flow laser analyzer (LAZMA Research-and-Production Association, Russian Federation. All the victims underwent surgical interventions to remove epi-, subdural, and intracerebral hematomas. A Codman subdural/intraparenchymatous intracranial pressure (ICD sensor (Johnson & Johnson, United Kingdom was intraoperatively inserted in the victims. Cerebral perfusion pressure (CPP was calculated using the generally accepted formula: CPP = MBP (mean blood pressure — ICD. ICD, CPP, and microcirculation were studied on postoperative days 1, 3, 5, and 7. Their values were recorded simultaneously. Ninety and 58 studies were conducted in the group of patients with good and fatal outcomes, respectively. Results. No correlation between the changes in MBP, ICD, and microcirculatory parameters suggested that the value of ICD was determined by the nature of brain damage and it was the leading and determining indicator in the diagnosis and treatment of secondary cerebral lesions. The amplitude of low-frequency fluctuations directly correlated with ICD, which indicated that they might be used to evaluate cerebral perfusion and impaired cerebral circulation indirectly in victims with severe brain injury. Conclusion. The laser Doppler flowmetric technique makes it possible not only to qualitatively, but also quantitatively determine changes in the tissue blood flow system in severe brain injury. With this technique, both the local and central

  16. Safety and effect on ablation size of hydrochloric acid-perfused radiofrequency ablation in animal livers.

    Science.gov (United States)

    Zhang, Tian-Qi; Huang, Sen-Miao; Gu, Yang-Kui; Gao, Fei; Huang, Zhi-Mei; Jiang, Xiong-Ying; Liu, Ding-Xin; Huang, Jin-Hua

    2018-02-26

    Our objective was to determine the safety and ablation size of hydrochloric acid-perfused radiofrequency ablation (HCl-RFA) in liver tissues, prospectively using in vivo rabbit and ex vivo porcine liver models. The livers in 30 rabbits were treated in vivo with perfusions of normal saline (controls) and HCl concentrations of 5%, 10%, 15%, and 20%, during RFA at 103 °C and 30 W for 3 min. For each experimental setting, six ablations were created. Safety was assessed by comparing baseline weight and selected laboratory values with those at 2, 7, and 14 days' post-ablation, and by histopathological analysis. The livers in 25 pigs were treated ex vivo with the same five perfusions during RFA at 103 °C, at both 30 W and 60 W, for 30 min. Ablation diameters and volumes were measured by two examiners. Rabbit weights and selected laboratory values did not differ significantly from baseline to 7 and 14 days' post-ablation, liver tissues outside the ablation zones were normal histologically, and adjacent organs showed no macroscopic damage. The mean ablation volumes in the porcine livers treated with HCl-RFA were all larger than those treated with normal saline perfusion during RFA (NS-RFA), at both 30 W and 60 W (p < 0.001). The largest ablation volume and transverse diameter were observed in the porcine livers during 10% HCl-RFA at 60 W, measuring 179.22 (SD = 24.79) cm 3 and 6.84 (SD = 0.36) cm, respectively. Based on our experiments, HCl-RFA in the liver appears to be as safe as NS-RFA while also resulting in larger ablation zones.

  17. Transport of benzo[alpha]pyrene in the dually perfused human placenta perfusion model: effect of albumin in the perfusion medium

    DEFF Research Database (Denmark)

    Mathiesen, Line; Rytting, Erik; Mose, Tina

    2009-01-01

    Transport of benzo[alpha]pyrene (BaP) across the placenta was examined because it is a ubiquitous and highly carcinogenic substance found in tobacco smoke, polluted air and certain foods. Foetal exposure to this substance is highly relevant but is difficult to estimate. The human placenta is unique...... compared to other species; since it is available without major ethical obstacles, we have used the human placenta perfusion model to study transport from mother to foetus. Placentas were donated after births at Rigshospitalet in Copenhagen from pregnant mothers who signed an informed consent. Ba......P is lipophilic and studies using cell culture medium in 6-hr placenta perfusions showed minimal transport through the placenta. To increase the solubility of BaP in perfusion medium and to increase physiological relevance, perfusions were also performed with albumin added to the perfusion medium [2 and 30 mg...

  18. Myocardial perfusion in type 2 diabetes with left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Hesse, Birger; Meyer, Christian; Nielsen, Flemming S

    2004-01-01

    The purpose of this study was to assess whether acute angiotensin-converting enzyme (ACE) inhibition would improve myocardial perfusion and perfusion reserve in a subpopulation of normotensive patients with diabetes and left ventricular hypertrophy (LVH), both independent risk factors of coronary...... disease. Using positron emission tomography (PET), we investigated the response of regional myocardial perfusion to acute ACE inhibition with i.v. infusion of perindoprilat (vs saline infusion as control, minimum interval 3 days) in 12 diabetic patients with LVH. Myocardial perfusion was quantified...... with controls, maximal perfusion was reduced in patients (1.8+/-0.6 vs 2.5+/-1.0 ml min(-1) g(-1); P2.7+/-1.0 vs 3.6+/-1.3; P=0.059). During perindoprilat infusion, myocardial perfusion reserve in patients increased to 3.9+/-0.9 ( P

  19. Magnetic Resonance Imaging of Ventilation and Perfusion in the Lung

    Science.gov (United States)

    Prisk, Gordon Kim (Inventor); Hopkins, Susan Roberta (Inventor); Buxton, Richard Bruce (Inventor); Pereira De Sa, Rui Carlos (Inventor); Theilmann, Rebecca Jean (Inventor); Cronin, Matthew Vincent (Inventor)

    2017-01-01

    Methods, devices, and systems are disclosed for implementing a fully quantitative non-injectable contrast proton MRI technique to measure spatial ventilation-perfusion (VA/Q) matching and spatial distribution of ventilation and perfusion. In one aspect, a method using MRI to characterize ventilation and perfusion in a lung includes acquiring an MR image of the lung having MR data in a voxel and obtaining a breathing frequency parameter, determining a water density value, a specific ventilation value, and a perfusion value in at least one voxel of the MR image based on the MR data and using the water density value to determine an air content value, and determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency.

  20. Reversible ventilation and perfusion abnormalities in unilateral obstructed lung

    International Nuclear Information System (INIS)

    Ward, H.E.; Jones, R.L.; King, E.G.; Sproule, B.J.; Fortune, R.L.

    1982-01-01

    An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (/sup 133/Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected /sup 133/Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal

  1. Brain perfusion: computed tomography and magnetic resonance techniques.

    Science.gov (United States)

    Copen, William A; Lev, Michael H; Rapalino, Otto

    2016-01-01

    Cerebral perfusion imaging provides assessment of regional microvascular hemodynamics in the living brain, enabling in vivo measurement of a variety of different hemodynamic parameters. Perfusion imaging techniques that are used in the clinical setting usually rely upon X-ray computed tomography (CT) or magnetic resonance imaging (MRI). This chapter reviews CT- and MRI-based perfusion imaging techniques, with attention to image acquisition, clinically relevant aspects of image postprocessing, and fundamental differences between CT- and MRI-based techniques. Correlations with cerebrovascular physiology and potential clinical applications of perfusion imaging are reviewed, focusing upon the two major classes of neurologic disease in which perfusion imaging is most often performed: primary perfusion disorders (including ischemic stroke, transient ischemic attack, and reperfusion syndrome), and brain tumors. © 2016 Elsevier B.V. All rights reserved.

  2. Quantitative analysis of SPECT imaging parameters in patients with resting perfusion defects on myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Pruthi, Ankur; Asopa, Ramesh; Rajan, M.G.R.; Basu, Sandip

    2010-01-01

    Functional status/contractile behaviour of hibernating myocardium was analyzed objectively by analyzing the available quantitative parameters obtained on gated SPECT myocardial perfusion imaging (MPI) using Emory cardiac toolbox (ECTB) software. Materials and Methods: In this retrospective study, 70 patients with perfusion defects on 99 Tc-Sestamibi MPI (12 females, 58 males) who also underwent 18 F-FDG Cardiac PET study for assessment of hibernating myocardium were included for analysis. Patients were divided in three categories based on summed rest score (SRS) obtained from ECTB software, depicting the extent of perfusion defects. In a study population matched for extent of perfusion defects, quantitative parameters obtained from ECTB software such as left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (EDV), left ventricular end systolic volume (ESV) and left ventricular stroke volume (SV) were compared between patients showing evidence of hibernating myocardium and patients showing no evidence of hibernating myocardium. Student 't' test was applied on the given observations and a P-value <0.05 was considered as a significant difference between the means in two categories. Results: There was no significant difference in LVEF, EDV, ESV and SV measurements between those who demonstrate hibernating myocardium and those who show no evidence of hibernating myocardium across all the categories of patients. Few trends were evident in the present study in LVEF, EDV and ESV measurements i.e., fall in mean LVEF with increasing SRS and rise in mean EDV and ESV with increasing SRS. Conclusions: The findings were consistent with the nature of hibernating myocardium i.e., non-contractile and dysfunctional. The fall in the LVEF was suggestive of deteriorating myocardial function with increasing extent of perfusion defects. The increasing left ventricular EDV and ESV with increasing extent of perfusion defects was suggestive of rising incidence of

  3. Assessment of lower extremities ischemic disease by thallium 201 perfusion scintigraphy in patients with diabetic angiopathy

    Directory of Open Access Journals (Sweden)

    Čizmić Milica

    2011-01-01

    Full Text Available Background/Aim. Tibial perfusion in diabetic microangiopathy is considered to be a diagnostic problem. A special place in quantifying muscle microcirculatory perfusion belongs to thallium 201 muscle perfusion scintigraphy (201Tl PS. Thallium, showing the characteristics of potassium (K+, enters a cell by means of active cell transportation and follows erythrocyte up to the tissue. The aim of this study was to determine if 201Tl PS of lower extremities (LE is a good method for estimating muscle microcirculatory perfusion in diabetic microangiopathy. Methods. The study included 32 patients of an average age 66.1 ± 14.9 years with signs of LE ischemia befalling into III and IV stage of ischemic disease according to the Lariche-Fontain classification. Out of that number there were 27 of the patients with non-insulin-dependent diabetes mellitus (NIDDM, while 5 of the patients were with Burger's disease and Raynand's disorder. Lower extremities PS was performed after 3 min of tibial loading by the use of dorsoplantar foot flexion and intravenous 74 MBq 201Tl as a 10-minute dynamic study. A 10 minute static scintigraphy was carried out of the gluteal region, femurs, tibias and feet per a position and repeated after 3 h at rest in the same projections. The results were interpreted visually and by the semiquantitive method using a program for calculating the number of pulses per pixel in the corresponding region over 1-, 2- and 10-minute dynamic study, thus obtaining numerical data for estimating perfusion. Binding ratio in both legs was estimated visually as low (1, medium (2 and significant (3 difference in both legs. The results were compared with doppler hemodynamic indices (PI and RI. Results. Regardless the group, 201Tl binding intensity rising was significantly 2 min after application, as compared to 1 min, and the obtained level of binding was maintained even after 10 min. In the group Fontain III the majority of the patients showed a medium

  4. [Assesment of lower extremities ischemic disease by thallium 201 perfusion scintigraphy in patients with diabetic angiopathy].

    Science.gov (United States)

    Cizmić, Milica; Pucar, Dragan; Zoranović, Uros

    2011-02-01

    Tibial perfusion in diabetic microangiopathy is considered to be a diagnostic problem. A special place in quantifying muscle microcirculatory perfusion belongs to thallium 201 muscle perfusion scintigraphy (201T1 PS). Thallium, showing the characteristics of potassium (K+), enters a cell by means of active cell transportation and follows erythrocyte up to the tissue. The aim of this study was to determine if T1 PS of lower extremities (LE) is a good method for estimating muscle microcirculatory perfusion in diabetic microangiopathy. The study included 32 patients of an average age 66.1 +/- 14.9 years with signs of LE ischemia befalling into III and IV stage of ischemic disease according to the Lariche-Fontain classification. Out of that number there were 27 of the patients with non-insulin-dependent diabetes mellitus (NIDDM), while 5 of the patients were with Burger's disease and Raynand's disorder. Lower extremities PS was performed after 3 min of tibial loading by the use of dorsoplantar foot flexion and intravenous 74 MBq 201T1 as a 10-minute dynamic study. A 10 minute static scintigraphy was carried out of the gluteal region, femurs, tibias and feet per a position and repeated after 3 h at rest in the same projections. The results were interpreted visually and by the semiquantitive method using a program for calculating the number of pulses per pixel in the corresponding region over 1-, 2- and 10-minute dynamic study, thus obtaining numerical data for estimating perfusion. Binding ratio in both legs was estimated visually as low (1), medium (2) and significant (3) difference in both legs. The results were compared with doppler hemodynamic indices (PI and RI). Regardless the group, 201T1 binding intensity rising was significantly 2 min after application, as compared to 1 min, and the obtained level of binding was maintained even after 10 min. In the group Fontain III the majority of the patients showed a medium difference in binding 201T1 (2) in regard to the

  5. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  6. Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study

    Directory of Open Access Journals (Sweden)

    Frederiksen Marie

    2010-07-01

    Full Text Available Abstract Background Polybrominated diphenyl ethers (PBDEs have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very high concern due to critical windows in fetal development. Methods A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored in the maternal and fetal compartments. In addition, the perfused cotyledon, the surrounding placental tissue as well as pre-perfusion placental tissue and umbilical cord plasma were also analysed. The PBDE analysis included Soxhlet extraction, clean-up by adsorption chromatography and GC-MS analysis. Results and Discussion Placental transfer of BDE-47 was faster and more extensive than for BDE-99. The fetal-maternal ratios (FM-ratio after four hours of perfusion were 0.47 and 0.25 for BDE-47 and BDE-99, respectively, while the indicative permeability coefficient (IPC measured after 60 minutes of perfusion was 0.26 h-1 and 0.10 h-1, respectively. The transport of BDE-209 seemed to be limited. These differences between the congeners may be related to the degree of bromination. Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue. Conclusion The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which should be included in risk assessment of PBDE exposure of women of child-bearing age.

  7. Characterization of transplacental transfer of paroxetine in perfused human placenta: development of a pharmacokinetic model to evaluate tapered dosing.

    Science.gov (United States)

    Nagai, Marie; Ohtani, Hisakazu; Satoh, Hiroki; Matsuoka, Sayo; Hori, Satoko; Fujii, Tomoyuki; Taketani, Yuji; Sawada, Yasufumi

    2013-12-01

    The aim of this study was to determine whether a tapered dosage regimen of paroxetine in pregnant women might be useful to avoid withdrawal syndromes in neonates after delivery. We characterized the transplacental transfer of paroxetine in perfused human placenta, fitting a pharmacokinetic model to the results and applying the model and parameters to evaluate a tapered dosage regimen. Paroxetine was perfused from the maternal or fetal side of an isolated human placental preparation with various perfusion protocols, and paroxetine concentrations in the effluent and placental tissue were determined. The transplacental pharmacokinetic parameters of paroxetine were estimated by simultaneous fitting of a five-compartment transplacental pharmacokinetic model to the set of paroxetine concentration profiles. The developed model and parameters were used to simulate the maternal and fetal concentrations of paroxetine, and the results were compared with reported data. Paroxetine showed a larger distribution volume in placental tissue and a smaller transplacental transfer as compared with antipyrine, a passive diffusion marker. A five-compartment model could well describe the transplacental transfer of paroxetine and could well simulate the maternal and umbilical venous concentrations of paroxetine at delivery. Transplacental transfer kinetic parameters of paroxetine were estimated by fitting a pharmacokinetic model to perfusion study data. The model and parameters appeared to be suitable for simulation of paroxetine kinetics in fetus. The model was also applicable to design a dosage regimen to avoid an abrupt decrease of paroxetine concentration in fetal plasma.

  8. The Benefits of Prone SPECT Myocardial Perfusion Imaging in Reducing Both Artifact Defects and Patient Radiation Exposure.

    Science.gov (United States)

    Stathaki, Maria; Koukouraki, Sophia; Papadaki, Emmanouela; Tsaroucha, Angeliki; Karkavitsas, Nikolaos

    2015-10-01

    Prone imaging has been demonstrated to minimize diaphragmatic and breast tissue attenuation. To determine the role of prone imaging on the reduction of unnecessary rest perfusion studies and coronary angiographies performed, thus decreasing investigation time and radiation exposure. We examined 139 patients, 120 with an inferior wall and 19 with an anterior wall perfusion defect that might represented attenuation artifact. Post-stress images were acquired in both the supine and prone position. Coronary angiography was used as the "gold standard" for evaluating coronary artery patency. The study was terminated and rest imaging was obviated in the presence of complete improvement of the defect in the prone position. Quantitative interpretation was performed. Results were compared with clinical data and coronary angiographic findings. Prone acquisition correctly revealed defect improvement in 89 patients (89/120) with inferior wall and 12 patients (12/19) with anterior wall attenuation artifact. Quantitative analysis demonstrated statistically significant difference in the mean summed stress scores (SSS) of supine and mean SSS of prone studies in patients with disappearing inferior wall defect in the prone position and patent right coronary artery (true negative results). The mean difference between SSS in supine and in prone position was higher with disappearing than with remaining defects. Technetium-99m (Tc-99m) tetrofosmin myocardial perfusion imaging with the patient in the prone position overcomes soft tissue attenuation; moreover it provides an inexpensive, accurate approach to limit the number of unnecessary rest perfusion studies and coronary angiographies performed.

  9. Self-esteem, social support, and satisfaction differences in women with adequate and inadequate prenatal care.

    Science.gov (United States)

    Higgins, P; Murray, M L; Williams, E M

    1994-03-01

    This descriptive, retrospective study examined levels of self-esteem, social support, and satisfaction with prenatal care in 193 low-risk postpartal women who obtained adequate and inadequate care. The participants were drawn from a regional medical center and university teaching hospital in New Mexico. A demographic questionnaire, the Coopersmith self-esteem inventory, the personal resource questionnaire part 2, and the prenatal care satisfaction inventory were used for data collection. Significant differences were found in the level of education, income, insurance, and ethnicity between women who received adequate prenatal care and those who received inadequate care. Women who were likely to seek either adequate or inadequate prenatal care were those whose total family income was $10,000 to $19,999 per year and high school graduates. Statistically significant differences were found in self-esteem, social support, and satisfaction between the two groups of women. Strategies to enhance self-esteem and social support have to be developed to reach women at risk for receiving inadequate prenatal care.

  10. Randomized Trial of Once-Daily Fluticasone Furoate in Children with Inadequately Controlled Asthma

    DEFF Research Database (Denmark)

    Oliver, Amanda J.; Covar, Ronina A.; Goldfrad, Caroline H.

    2016-01-01

    Objective To evaluate the dose-response, efficacy, and safety of fluticasone furoate (FF; 25 µg, 50 µg, and 100 µg), administered once daily in the evening during a 12-week treatment period to children with inadequately controlled asthma. Study design This was a Phase IIb, multicenter, stratified...

  11. Wearable Devices for Classification of Inadequate Posture at Work Using Neural Networks.

    Science.gov (United States)

    Barkallah, Eya; Freulard, Johan; Otis, Martin J-D; Ngomo, Suzy; Ayena, Johannes C; Desrosiers, Christian

    2017-09-01

    Inadequate postures adopted by an operator at work are among the most important risk factors in Work-related Musculoskeletal Disorders (WMSDs). Although several studies have focused on inadequate posture, there is limited information on its identification in a work context. The aim of this study is to automatically differentiate between adequate and inadequate postures using two wearable devices (helmet and instrumented insole) with an inertial measurement unit (IMU) and force sensors. From the force sensors located inside the insole, the center of pressure (COP) is computed since it is considered an important parameter in the analysis of posture. In a first step, a set of 60 features is computed with a direct approach, and later reduced to eight via a hybrid feature selection. A neural network is then employed to classify the current posture of a worker, yielding a recognition rate of 90%. In a second step, an innovative graphic approach is proposed to extract three additional features for the classification. This approach represents the main contribution of this study. Combining both approaches improves the recognition rate to 95%. Our results suggest that neural network could be applied successfully for the classification of adequate and inadequate posture.

  12. The Inadequacy of Academic Environment Contributes to Inadequate Teaching and Learning Phenomena

    Science.gov (United States)

    Quasim, Shahla; Arif, Muhammad Shahbaz

    2014-01-01

    This study aims at the inadequacy of academic environment as an indicator contributing to the inadequate teaching and learning situation in Pakistan. The main focus is to look into the low proficiency of students in the subject of English at secondary school level. A comprehensive questionnaire was designed from the literature concerned and The…

  13. 25 CFR 170.811 - What happens if lack of funds results in inadequate maintenance?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What happens if lack of funds results in inadequate maintenance? 170.811 Section 170.811 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM BIA Road Maintenance § 170.811 What happens if lack of funds...

  14. Do infants with cow's milk protein allergy have inadequate levels of vitamin D?

    Science.gov (United States)

    Silva, Cristiane M; Silva, Silvia A da; Antunes, Margarida M de C; Silva, Gisélia Alves Pontes da; Sarinho, Emanuel Sávio Cavalcanti; Brandt, Katia G

    To verify whether infants with cow's milk protein allergy have inadequate vitamin D levels. This cross-sectional study included 120 children aged 2 years or younger, one group with cow's milk protein allergy and a control group. The children were recruited at the pediatric gastroenterology, allergology, and pediatric outpatient clinics of a university hospital in the Northeast of Brazil. A questionnaire was administered to the caregiver and blood samples were collected for vitamin D quantification. Vitamin D levels <30ng/mL were considered inadequate. Vitamin D level was expressed as mean and standard deviation, and the frequency of the degrees of sufficiency and other variables, as proportions. Infants with cow's milk protein allergy had lower mean vitamin D levels (30.93 vs.35.29ng/mL; p=0.041) and higher deficiency frequency (20.3% vs.8.2; p=0.049) than the healthy controls. Exclusively or predominantly breastfed infants with cow's milk protein allergy had higher frequency of inadequate vitamin D levels (p=0.002). Regardless of sun exposure time, the groups had similar frequencies of inadequate vitamin D levels (p=0.972). Lower vitamin D levels were found in infants with CMPA, especially those who were exclusively or predominantly breastfed, making these infants a possible risk group for vitamin D deficiency. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  15. Sleep deprivation in the last trimester of pregnancy and inadequate vitamin D: Is there a relationship?

    Directory of Open Access Journals (Sweden)

    Suzan Gunduz

    2016-01-01

    Conclusion: Inadequate vitamin D and poor sleep quality are prevalent in pregnant women, but low levels of vitamin D are not associated with poor sleep quality. Further studies with larger sample sizes and studies that include preterm deliveries and special sleep disorders should be performed to understand this issue better.

  16. Inadequate Evidence for Multiple Intelligences, Mozart Effect, and Emotional Intelligence Theories

    Science.gov (United States)

    Waterhouse, Lynn

    2006-01-01

    I (Waterhouse, 2006) argued that, because multiple intelligences, the Mozart effect, and emotional intelligence theories have inadequate empirical support and are not consistent with cognitive neuroscience findings, these theories should not be applied in education. Proponents countered that their theories had sufficient empirical support, were…

  17. Perfusion lung scanning: differentiation of primary from thromboembolic pulmonary hypertension

    International Nuclear Information System (INIS)

    Lisbona, R.; Kreisman, H.; Novales-Diaz, J.; Derbekyan, V.

    1985-01-01

    Of eight patients with pulmonary arterial hypertension, final diagnosis established by autopsy or angiography, four had primary hypertension and four hypertension from thromboembolism. The perfusion lung scan was distinctly different in the two groups. The lung scan in primary pulmonary hypertension was associated with nonsegmental, patchy defects of perfusion, while in thromboembolic hypertensives it was characterized by segmental and/or lobar defects of perfusion with or without subsegmental defects. The perfusion lung scan is a valuable, noninvasive study in the evaluation of the patient with pulmonary hypertension of undetermined cause and in the exclusion of occult large-vessel pulmonary thromboembolism

  18. Perfusion CT imaging of the liver: review of clinical applications

    Science.gov (United States)

    Oğul, Hayri; Kantarcı, Mecit; Genç, Berhan; Pirimoğlu, Berhan; Çullu, Neşat; Kızrak, Yeşim; Yılmaz, Ömer; Karabulut, Nevzat

    2014-01-01

    Perfusion computed tomography (CT) has a great potential for determining hepatic and portal blood flow; it offers the advantages of quantitative determination of lesion hemodynamics, distinguishing malignant and benign processes, as well as providing morphological data. Many studies have reported the use of this method in the assessment of hepatic tumors, hepatic fibrosis associated with chronic liver disease, treatment response following radiotherapy and chemotherapy, and hepatic perfusion changes after radiological or surgical interventions. The main goal of liver perfusion imaging is to improve the accuracy in the characterization of liver disorders. In this study, we reviewed the clinical application of perfusion CT in various hepatic diseases. PMID:24834487

  19. Prior CT May Improve Diagnostic Confidence in Myocardial Perfusion Imaging.

    Science.gov (United States)

    Mehta, Pareen; Wassef, Heidi; Colletti, Patrick M

    2015-10-01

    Many patients with matching myocardial perfusion imaging defects may have prior CT examinations that include the myocardial region of interest, such as a CT chest or CT abdomen. We correlate these perfusion defects with available prior CT examinations to determine if this will improve diagnostic confidence. Myocardial perfusion scans were reviewed to identify cases with myocardial perfusion defects and prior CT imaging that included the myocardium. The CT was reviewed for evidence of myocardial injury that correlated with the perfusion defect. A retrospective review of 732 myocardial perfusion scans was performed, of which 69 cases with perfusion defects were identified that also had prior CT imaging available for review. Of this subset of patients, 19 patients had findings on the CT scan compatible with ischemia or infarction in the expected region of the perfusion defect, which allowed for a more confident diagnosis. Reviewing a prior CT scan, if available, during the interpretation of a myocardial perfusion scan, can help improve diagnostic confidence in over 25% of cases. This can lead to decreased indeterminate results and can be used to potentially avoid unhelpful further testing.

  20. Perfusion index as a possible predictor for postanesthetic shivering.

    Science.gov (United States)

    Kuroki, Chiharu; Godai, Kohei; Hasegawa-Moriyama, Maiko; Kuniyoshi, Tamotsu; Matsunaga, Akira; Kanmura, Yuichi; Kuwaki, Tomoyuki

    2014-02-01

    Postanesthetic shivering can be triggered by surgical stress and several aspects of anesthetic management and is frequently preceded by a decrease in peripheral blood flow due to thermoregulatory vasoconstriction. As perfusion index correlates with peripheral blood flow, we examined whether perioperative perfusion index, measured using pulse oximetry, might be correlated with postanesthetic shivering. Twenty-eight patients presenting for elective abdominal surgery were enrolled. Core (esophagus) and peripheral (finger) temperatures and perfusion index were recorded in the perioperative periods. Correlations between perfusion index and peripheral temperature and core-to-peripheral temperature gradient were then explored. Plasma levels of epinephrine and norepinephrine were also measured. The extent of shivering was graded after emergence from anesthesia. Perfusion index declined before emergence from anesthesia in patients who then developed postanesthetic shivering. This coincided with the time at which the difference between core and peripheral temperature became dissociated and peripheral temperature declined. Perioperative perfusion index was correlated with peripheral temperature and peripheral-core temperature gradient. Perfusion index at closure of the peritoneum predicted postanesthetic shivering and was significantly correlated with the extent of shivering. Plasma levels of both epinephrine and norepinephrine were significantly elevated after shivering events. Perfusion index was significantly lower in patients with postanesthetic shivering before emergence from anesthesia, indicating that measurement of perfusion index during and before the end of anesthesia might be a useful means of predicting postanesthetic shivering.

  1. Reproducibility of rest and exercise stress contrast-enhanced calf perfusion magnetic resonance imaging in peripheral arterial disease

    Directory of Open Access Journals (Sweden)

    Jiji Ronny S

    2013-01-01

    Full Text Available Abstract Background The purpose was to determine the reproducibility and utility of rest, exercise, and perfusion reserve (PR measures by contrast-enhanced (CE calf perfusion magnetic resonance imaging (MRI of the calf in normal subjects (NL and patients with peripheral arterial disease (PAD. Methods Eleven PAD patients with claudication (ankle-brachial index 0.67 ±0.14 and 16 age-matched NL underwent symptom-limited CE-MRI using a pedal ergometer. Tissue perfusion and arterial input were measured at rest and peak exercise after injection of 0.1 mM/kg of gadolinium-diethylnetriamine pentaacetic acid (Gd-DTPA. Tissue function (TF and arterial input function (AIF measurements were made from the slope of time-intensity curves in muscle and artery, respectively, and normalized to proton density signal to correct for coil inhomogeneity. Perfusion index (PI = TF/AIF. Perfusion reserve (PR = exercise TF/ rest TF. Intraclass correlation coefficient (ICC was calculated from 11 NL and 10 PAD with repeated MRI on a different day. Results Resting TF was low in NL and PAD (mean ± SD 0.25 ± 0.18 vs 0.35 ± 0.71, p = 0.59 but reproducible (ICC 0.76. Exercise TF was higher in NL than PAD (5.5 ± 3.2 vs. 3.4 ± 1.6, p = 0.04. Perfusion reserve was similar between groups and highly variable (28.6 ± 19.8 vs. 42.6 ± 41.0, p = 0.26. Exercise TF and PI were reproducible measures (ICC 0.63 and 0.60, respectively. Conclusion Although rest measures are reproducible, they are quite low, do not distinguish NL from PAD, and lead to variability in perfusion reserve measures. Exercise TF and PI are the most reproducible MRI perfusion measures in PAD for use in clinical trials.

  2. Peripapillary Scleral Thickness in Perfusion-Fixed Normal Monkey Eyes

    Science.gov (United States)

    Downs, J. Crawford; Blidner, Richard A.; Bellezza, Anthony J.; Thompson, Hilary W.; Hart, Richard T.; Burgoyne, Claude F.

    2009-01-01

    Purpose To characterize the thickness of the peripapillary sclera in perfusion-fixed normal monkey eyes so as to build accurate computational models of intraocular pressure (IOP)-related stress and strain within these tissues. Methods Nine rhesus monkeys were perfusion fixed, each with one normal eye set to an IOP of 10 mm Hg by manometer. A 6-mm-diameter specimen containing the optic nerve head and peripapillary sclera was trephined from each scleral shell and cut into 4-μm serial sagittal sections across the scleral canal opening, either horizontally (four eyes) or vertically (five eyes). The thickness of the peripapillary sclera was measured on every 24th section at 100-μm intervals from the posterior scleral canal opening (PSCO) to the peripheral edge of the specimen. The data were pooled by quadrant (superior, inferior, nasal, and temporal), regions within each quadrant, and distance from the PSCO, overall and for individual eyes, and subjected to analysis of variance. Results In terms of distance from the PSCO, the peripapillary sclera was thinnest nearest the PSCO (201 μm, nasal; 201 μm, temporal; 240 μm, inferior; 249 μm, superior), thickened progressively to a maximum in the midperiphery approximately 600 to 1000 μm from the PSCO (326 μm, nasal; 415 μm, superior; 420 μm, temporal; 422 μm, inferior), and thinned again peripherally in all quadrants. The peripapillary sclera was thinner in the nasal quadrant when compared with the other quadrants superiorly, inferiorly, and temporally (central region means of 291 μm, nasal; 369 μm, superior; 372 μm, inferior; and 369 μm, temporal; P < 0.0001). Conclusions In the normal monkey eye, peripapillary scleral thickness varies significantly with distance from the posterior scleral canal opening and is thinner in the nasal quadrant than in the other quadrants. These differences are substantial and are likely to affect the magnitude of IOP-related stress and strain within these tissues for a given level

  3. Flow measurements in a blood-perfused collagen vessel using x-ray micro-particle image velocimetry.

    Directory of Open Access Journals (Sweden)

    Elizabeth Antoine

    Full Text Available Blood-perfused tissue models are joining the emerging field of tumor engineering because they provide new avenues for modulation of the tumor microenvironment and preclinical evaluation of the therapeutic potential of new treatments. The characterization of fluid flow parameters in such in-vitro perfused tissue models is a critical step towards better understanding and manipulating the tumor microenvironment. However, traditional optical flow measurement methods are inapplicable because of the opacity of blood and the thickness of the tissue sample. In order to overcome the limitations of optical method we demonstrate the feasibility of using phase-contrast x-ray imaging to perform microscale particle image velocimetry (PIV measurements of flow in blood perfused hydrated tissue-representative microvessels. However, phase contrast x-ray images significantly depart from the traditional PIV image paradigm, as they have high intensity background, very low signal-to-noise ratio, and volume integration effects. Hence, in order to achieve accurate measurements special attention must be paid to the image processing and PIV cross-correlation methodologies. Therefore we develop and demonstrate a methodology that incorporates image preprocessing as well as advanced PIV cross-correlation methods to result in measured velocities within experimental uncertainty.

  4. Perfusion Intensity Correlates with Expression Levels of Psoriasis-Related Genes and Proteins

    NARCIS (Netherlands)

    Hendriks, Anke G M; Steenbergen, Wiendelt; Zeeuwen, Patrick L J M; Schalkwijk, Joost; Hondebrink, Erwin; Klitsie, Michiel A J; Schreurs, Ruud; Van De Kerkhof, Peter C M; Seyger, Marieke M B

    2015-01-01

    Background: Previous research revealed heterogeneity in the perfusion intensity within clinically homogenous-Appearing plaques, without differences in erythema. In addition, an increased perfusion was found within the perilesional skin. This raises the question whether the heterogeneity in perfusion

  5. In-effort perfusion pulmonary tomo-scintigraphies for pre-surgery evaluation of severe emphysema; Tomoscintigraphies pulmonaires de perfusion a l`effort pour l`evaluation preoperatoire des emphysemateux severes

    Energy Technology Data Exchange (ETDEWEB)

    Poiseau, E. [Service de Medecine Nucleaire, Hopital Beaujon, Clichy (France); Roue, C. [Service de Pneumologie, Hopital Beaujon, Clichy (France); Bonnin, F.; Stievenart, J.L. [Service de Medecine Nucleaire, Hopital Beaujon, Clichy (France); Fournier, M. [Service de Pneumologie, Hopital Beaujon, Clichy (France); Bok, B. [Service de Medecine Nucleaire, Hopital Beaujon, Clichy (France)

    1997-12-31

    The pulmonary reduction surgery improves the in-effort tolerance of certain severe emphysema, possibly by the compression of zones of adjacent healthy pulmonary parenchyma. Six patients afflicted with severe emphysema (5 M and 1 F, 20 to 63 years old) benefited at each 3 days by an at-rest and in-effort perfusion pulmonary tomo-scintigraphy (PPTS), after a trial interval of 6 minutes. After injection IV of 6 mCi of MAA-{sup 99m}Tc, in sitting position, 120 projection images were acquired with a single-head camera on a 128 x 128 matrix, with a high resolution collimator. After reconstruction with a Metz filter, without corrections of attenuations, the coronal and cross sections were recorded on films in a standard procedure. These were visually interpreted by two independent senior physicians. The procedure has been tolerated by all the patients. Differences of pulmonary perfusion occurred at rest in comparison with the in-effort condition in 4 patients. In all the cases concerned were the zones of pulmonary parenchyma appearing as strongly injured in tomodensitometry. The in-effort pulmonary perfusion improves in 3 patients and impairs in one patient. The role of bubble and implied pulmonary diseases in the deterioration of pulmonary function, respectively, is difficult to estimate. The improvement of in-effort pulmonary perfusion could suggest the persistence of functional pulmonary tissue. On the other side, its deterioration could express the compressive character of bubbles and thus could be an indicator of severity. The observation during this pilot study of the differences between at-rest and in-effort pulmonary perfusion urges utilisation of a tool of analysis of image superposition (PPTS and scans) to study in a group of patients the correlations between the perfusion variations and the post-surgery development, in order to know better the pathophysiology of diseases and select better the patients

  6. Metabolomic perfusate analysis during kidney machine perfusion: the pig provides an appropriate model for human studies.

    Directory of Open Access Journals (Sweden)

    Jay Nath

    Full Text Available Hypothermic machine perfusion offers great promise in kidney transplantation and experimental studies are needed to establish the optimal conditions for this to occur. Pig kidneys are considered to be a good model for this purpose and share many properties with human organs. However it is not established whether the metabolism of pig kidneys in such hypothermic hypoxic conditions is comparable to human organs.Standard criteria human (n = 12 and porcine (n = 10 kidneys underwent HMP using the LifePort Kidney Transporter 1.0 (Organ Recovery Systems using KPS-1 solution. Perfusate was sampled at 45 minutes and 4 hours of perfusion and metabolomic analysis performed using 1-D 1H-NMR spectroscopy.There was no inter-species difference in the number of metabolites identified. Of the 30 metabolites analysed, 16 (53.3% were present in comparable concentrations in the pig and human kidney perfusates. The rate of change of concentration for 3-Hydroxybutyrate was greater for human kidneys (p<0.001. For the other 29 metabolites (96.7%, there was no difference in the rate of change of concentration between pig and human samples.Whilst there are some differences between pig and human kidneys during HMP they appear to be metabolically similar and the pig seems to be a valid model for human studies.

  7. Xeno- and auto-perfusion of rabbit kidney. Machine perfusion with blood at 37 degrees C

    DEFF Research Database (Denmark)

    Jørgensen, K A; Kemp, E; Barfort, P

    1985-01-01

    Five rabbit kidneys were perfused with human blood and another five with their own blood in a re-circulating oxygenated system at 37 degrees C. The flow decreased to 2 ml/min. within 30 min. in all xenoperfusions, while none of the autoperfused had decreased to this level by 60 min. Endothelial...

  8. Effects of microwave radiation on living tissues

    Energy Technology Data Exchange (ETDEWEB)

    Surrell, J.A.; Alexander, R.C.; Cohle, S.D.; Lovell, F.R. Jr.; Wehrenberg, R.A.

    1987-08-01

    Prompted by an alleged case of child abuse resulting from microwave oven burns and the discovery of one other case, an animal model was chosen to explore microwave burn characteristics upon living, perfusing tissue. Anesthetized piglets were exposed to radiation from a standard household microwave oven for varying lengths of time, sufficient to result in full-thickness skin and visceral burns. Characteristic burn patterns were grossly identified. Biopsies studied with both light and electron microscopy demonstrated a pattern of relative layered tissue sparing. Layered tissue sparing is characterized by burned skin and muscle, with relatively unburned subcutaneous fat between these two layers. These findings have important forensic and patient care implications.

  9. Vascularization of soft tissue engineering constructs

    DEFF Research Database (Denmark)

    Pimentel Carletto, Rodrigo

    with mechanical properties in the range of soft tissues has not been fully achieved. My project focused on the fabrication and the active perfusion of hydrogel constructs with multi-dimensional vasculature and controlled mechanical properties targeting soft tissues. Specifically, the initial part of the research...... nanotechnology-based paradigm for engineering vascularised liver tissue for transplantation”) and the Danish National Research Foundation and Villum Foundation’s Center for Intelligent Drug delivery and sensing Using microcontainers and Nanomechanics (Danish National Research Foundation (DNRF122)....

  10. Bioreactor Technology in Cardiovascular Tissue Engineering

    Science.gov (United States)

    Mertsching, H.; Hansmann, J.

    Cardiovascular tissue engineering is a fast evolving field of biomedical science and technology to manufacture viable blood vessels, heart valves, myocar-dial substitutes and vascularised complex tissues. In consideration of the specific role of the haemodynamics of human circulation, bioreactors are a fundamental of this field. The development of perfusion bioreactor technology is a consequence of successes in extracorporeal circulation techniques, to provide an in vitro environment mimicking in vivo conditions. The bioreactor system should enable an automatic hydrodynamic regime control. Furthermore, the systematic studies regarding the cellular responses to various mechanical and biochemical cues guarantee the viability, bio-monitoring, testing, storage and transportation of the growing tissue.

  11. Pseudoketogenesis in the perfused rat heart

    Energy Technology Data Exchange (ETDEWEB)

    Fink, G.; Desrochers, S.; Des Rosiers, C.; Garneau, M.; David, F.; Daloze, T.; Landau, B.R.; Brunengraber, H.

    1988-12-05

    Ketogenesis is usually measured in vivo by dilution of tracers of (3R)-hydroxybutyrate or acetoacetate. We show that, in perfused working rat hearts, the specific activities of (3R)-hydroxybutyrate and acetoacetate are diluted by isotopic exchanges in the absence of net ketogenesis. We call this process pseudoketogenesis. When hearts are perfused with buffer containing 2.3 mM of (4-3H)- plus (3-14C)acetoacetate, the specific activities of (4-3H) and (3-14C)acetoacetate decrease while C-1 of acetoacetate becomes progressively labeled with 14C. This is explained by the reversibility of reactions catalyzed by mitochondrial 3-oxoacid-CoA transferase and acetoacetyl-CoA thiolase. After activation of labeled acetoacetate, the specific activity of acetoacetyl-CoA is diluted by unlabeled acetoacetyl-CoA derived from endogenous fatty acids or glucose. Acetoacetyl-CoA thiolase partially exchanges 14C between C-1 and C-3 of acetoacetyl-CoA. Finally, 3-oxoacid-CoA transferase liberates weakly labeled acetoacetate which dilutes the specific activity of extracellular acetoacetate. An isotopic exchange in the reverse direction is observed when hearts are perfused with unlabeled acetoacetate plus (1-14C)-, (13-14C)-, or (15-14C)palmitate; here also, acetoacetate becomes labeled on C-1 and C-3. Computations of specific activities of (3R)-hydroxybutyrate, acetoacetate, and acetyl-CoA yield minimal rates of pseudoketogenesis ranging from 19 to 32% of the net uptake of (3R)-hydroxybutyrate plus acetoacetate by the heart.

  12. Myocardial perfusion tomography with 7-pinhole collimator

    Energy Technology Data Exchange (ETDEWEB)

    Yonekura, Y.; Mukai, T.; Yamamoto, K. (Kyoto Univ. (Japan). Faculty of Medicine)

    1980-12-01

    The clinical efficacy of tomographic presentation of myocardial perfusion imaging with 7-pinhole collimator was evaluated. 35 cases including 5 normals, 4 patients with diffuse left ventricular hypertrophy, 21 with coronary artery disease (CAD) and 5 with hypertrophic cardiomyopathy (HCM) documented by coronary angiography and left ventriculography were selected for this study. Following the conventional /sup 201/Tl myocardial perfusion imaging (MPI), myocardial perfusion tomography (MPT) with 7-pinhole collimator was performed in both LAO and RAO projection. In addition, to examine wall motion abnormalities tomographically, /sup 201/Tl MPI as well as sup(99m)Tc-RBC blood pool imaging were gated to reconstruct multigated MPT (MGMPT) and multigated cardiac pool tomography (MGCPT). The detectability of the defect of the 7-pinhole tomography was compared with that of the conventional image using a cardiac phantom. The same degree of detectability was shown with both these two images. The MPT in LAO projection revealed superior sensitivity to the conventional MPI in the case of inferior wall infarction, and the MPT in RAO projection revealed superior sensitivity in the case of anterior wall infarction. A combination of the MGMPT and MGCPT succeeded in visualizing a subendocardial infarction as a focal gap between these two images. In the case of the small infarction undetectable in the conventional MPI, it can be seen as subtle wall motion abnormalities in the tomographic presentation in movie format. An asymmetrical hypertrophy in HCM can readily be localized in tomographic visualization. Tomographic reconstruction with 7-pinhole collimator from the optimal tomographic plane should be attempted, when the conventional display is equivocal.

  13. Fast Registration of Cardiac Perfusion MRI

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Larsson, Henrik B. W.

    2003-01-01

    This abstract presents a novel method for registration of cardiac perfusion MRI sequences. By performing complex analyses of variance and clustering in an annotated training set off-line, our method provides real-time segmentation in an on-line setting. This renders the method feasible for live...... motion-compensation in MR scanners. Changes in image intensity during the bolus passage are modelled by an Active Appearance Model augmented with a cluster analysis of the training set. Preliminary validation carried out using five subjects showed acceptable segmentation accuracy produced very rapidly...

  14. Stress-only myocardial perfusion scintigraphy

    DEFF Research Database (Denmark)

    Ejlersen, June A; May, Ole; Mortensen, Jesper

    2017-01-01

    and no previous coronary artery disease underwent a 2-day stress (exercise)/rest, gated, and attenuation-corrected (AC), 99m-technetium-sestamibi perfusion study, followed by invasive coronary angiography. The stress datasets were evaluated twice by four physicians with two different training levels (expert...... and novice): familiar and unfamiliar with AC. The two experts also made a consensus reading of the integrated stress-rest datasets. The consensus reading and quantitative data from the invasive coronary angiography were applied as reference methods. RESULTS: The sensitivity/specificity were 0...

  15. Restrictions in systemic and locomotor skeletal muscle perfusion, oxygen supply and VO2 during high-intensity whole-body exercise in humans

    DEFF Research Database (Denmark)

    Mortensen, S.P.; Damsgaard, R.; Dawson, E.A.

    2008-01-01

    Perfusion to exercising skeletal muscle is regulated to match O(2) delivery to the O(2) demand, but this regulation might be compromised during or approaching maximal whole-body exercise as muscle blood flow for a given work rate is blunted. Whether muscle perfusion is restricted when there is an......Perfusion to exercising skeletal muscle is regulated to match O(2) delivery to the O(2) demand, but this regulation might be compromised during or approaching maximal whole-body exercise as muscle blood flow for a given work rate is blunted. Whether muscle perfusion is restricted when...... there is an extreme metabolic stimulus to vasodilate during supramaximal exercise remains unknown. To examine the regulatory limits of systemic and muscle perfusion in exercising humans, we measured systemic and leg haemodynamics, O(2) transport, and , and estimated non-locomotor tissue perfusion during constant load...... supramaximal cycling (498 +/- 16 W; 110% of peak power; mean +/- S.E.M.) in addition to both incremental cycling and knee-extensor exercise to exhaustion in 13 trained males. During supramaximal cycling, cardiac output (Q), leg blood flow (LBF), and systemic and leg O(2) delivery and reached peak values after...

  16. Diagnostic value of dynamic perfusion MR imaging in benign and malignant musculoskeletal lesions

    International Nuclear Information System (INIS)

    Choi, Byeong Kyoo; Lee, Sang Hoon; Cha, Ji Hyeon; Kim, Sung Moon; Shin, Myung Jin; Han, Heon; Kim, Sam Soo; Lee, Ji Yeon; Jeon, Yong Hwan

    2008-01-01

    To assess the diagnostic value of dynamic perfusion MR imaging for differentiation between benign and malignant musculoskeletal lesions. Dynamic perfusion MR imaging was performed using a 3.0 T system in 32 female and 30 male patients (aged 10-90 years, mean age, 43 years). Following the assessment of the precontrast imaging, a dynamic study was performed. This dynamic technique allowed for 638 images to be obtained at 11 levels throughout the lesion. Twenty-eight lesions originated within bone (8 benign, 20 malignant), whereas 34 lesions were of soft tissue origin (22 benign, 12 malignant). The final diagnosis was histopathologically confirmed in all patients. To differentiate between benign and malignant lesions, we analyzed the four parameters: (maximal relative enhancement (MRE), time to peak (TTP), wash in rate (WI), steepest slope (SS) and the distribution of time intensity curve (TIC) patterns. The TTP, WI, and SS values of malignant lesions were statistically significant from those of benign lesions(ρ < 0.05). However, the difference for the MRE values was not statistically significant. The distribution of TIC patterns was a helpful indicator of benign or malignant state, however the difference between the two states was not significant. Dynamic perfusion MR imaging is a helpful tool in differentiating benign and malignant musculoskeletal lesions

  17. Renal MR angiography and perfusion in the pig using hyperpolarized water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Hansen, Esben Søvsø Szocska; Tougaard, Rasmus Stilling

    2016-01-01

    Purpose: To study hyperpolarized water as an angiographyand perfusion tracer in a large animal model.Methods: Protons dissolved in deuterium oxide (D2O) werehyperpolarized in a SPINlab dissolution dynamic nuclear polari-zation (dDNP) polarizer and subsequently investigated in vivo ina pig model...... at 3 Tesla (T). Approximately 15 mL of hyperpolar-ized water was injected in the renal artery by hand over 4–5 s.Results: A liquid state polarization of 5.3 6 0.9% of 3.8 M pro-tons in 15 mL of deuterium oxide was achieved with a T1of24 6 1 s. This allowed injection through an arterial catheterinto...... the renal artery and subsequently high-contrast imaging ofthe entire kidney parenchyma over several seconds. Thedynamic images allow quantification of tissue perfusion, with amean cortical perfusion of 504 6 123 mL/100 mL/min.Conclusion: Hyperpolarized water MR imaging was success-fully demonstrated...

  18. CT perfusion mapping of hemodynamic disturbances associated to acute spontaneous intracerebral hemorrhage

    International Nuclear Information System (INIS)

    Fainardi, Enrico; Borrelli, Massimo; Saletti, Andrea; Ceruti, Stefano; Tamarozzi, Riccardo; Schivalocchi, Roberta; Cavallo, Michele; Azzini, Cristiano; Chieregato, Arturo

    2008-01-01

    We sought to quantify perfusion changes associated to acute spontaneous intracerebral hemorrhage (SICH) by means of computed tomography perfusion (CTP) imaging. We studied 89 patients with supratentorial SICH at admission CT by using CTP scanning obtained within 24 h after symptom onset. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV) and mean transit time (rMTT) levels were measured in four different regions of interest manually outlined on CT scan: (1) hemorrhagic core; (2) perihematomal low-density area; (3) 1 cm rim of normal-appearing brain tissue surrounding the perilesional area; and (4) a mirrored area, including the clot and the perihematomal region, located in the non-lesioned contralateral hemisphere. rCBF, rCBV, and rMTT mean levels showed a centrifugal distribution with a gradual increase from the core to the periphery (p 20 ml) hematomas (p<0.01 and p <0.02, respectively). Multi-parametric CTP mapping of acute SICH indicates that perfusion values show a progressive improvement from the core to the periphery. In the first 24 h, perihemorrhagic region was hypoperfused with CTP values which were not suggestive of ischemic penumbra destined to survive but more likely indicative of edema formation. These findings also argue for a potential influence of early amounts of bleeding on perihematomal hemodynamic abnormalities. (orig.)

  19. Reduced Cerebrovascular Reactivity and Increased Resting Cerebral Perfusion in Rats Exposed to a Cafeteria Diet.

    Science.gov (United States)

    Gomez-Smith, Mariana; Janik, Rafal; Adams, Conner; Lake, Evelyn M; Thomason, Lynsie A M; Jeffers, Matthew S; Stefanovic, Bojana; Corbett, Dale

    2018-02-10

    To better understand the effects of a diet high in fat, sugar, and sodium on cerebrovascular function, Sprague Dawley rats were chronically exposed to a Cafeteria diet. Resting cerebral perfusion and cerebrovascular reactivity was quantified using continuous arterial spin labeling (CASL) magnetic resonance imaging (MRI). In addition, structural changes to the cerebrovasculature and susceptibility to ischemic lesion were examined. Compared to control animals fed standard chow (SD), Cafeteria diet (CAF) rats exhibited increased resting brain perfusion in the hippocampus and reduced cerebrovascular reactivity in response to 10% inspired CO 2 challenges in both the hippocampus and the neocortex. CAF rats switched to chow for one month (SWT) exhibited improved resting perfusion in the hippocampus as well as improved cerebrovascular reactivity in the neocortex. However, the diet switch did not correct cerebrovascular reactivity in the hippocampus. These changes were not accompanied by alterations in the structural integrity of the cerebral microvasculature, examined using rat endothelial cell antigen-1 (RECA-1) and immunoglobulin G (IgG) immunostaining. Also, the extent of tissue damage induced by endothelin-1 injection into sensorimotor cortex was not affected by the Cafeteria diet. These results demonstrate that short-term consumption of an ultra-processed diet reduces cerebrovascular reactivity. This effect persists after dietary normalization despite recovery of peripheral symptomatology. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Influence of risk area size and location on native collateral resistance and ischemic zone perfusion

    International Nuclear Information System (INIS)

    Gumm, D.C.; Cooper, S.M.; Thompson, S.B.; Marcus, M.L.; Harrison, D.C.

    1988-01-01

    To examine the effect of risk area size on collateral resistance and ichemic region perfusion, the authors produced different sized risk areas by occluding either the left anterior descending (LAD) or the circumflex (Cx) coronary artery at different sites. The most proximal occlusion of the LAD and Cx produced risk areas of 43 ± 5 and 36 ± 2% of left ventricular (LV) mass, respectively, whereas distal LAD and Cx occlusions produced risk areas of 13 ± 2 and 17 ± 2% of LV weight, respectively. Although total collateral flow was highest to the largest risk areas, collateral flow per 100 g of ischemic myocardium was 80% higher to the small LAD risk area compared with the large LAD risk area and 43% higher to the small Cx risk area compared with the large Cx risk area. Collateral resistance, calculated from the transcollateral pressure and perfusion per 100 g of myocardium was significantly lower in the small risk areas than in the large ones. They examined the effect of risk area location on collateral perfusion and resistance. These experiments show that collateral resistance is influenced both by ischemic region size and location. Small risk areas receive more collateral flow per mass of tissue than large risk areas, and apical risk areas receive greater quantities of collateral flow than those located at the base. These data may explain why small risk areas often do not develop infarction after coronary occlusion

  1. Comparison of prone and supine positions in myocardial perfusion SPECT on diaphragmatic attenuation

    International Nuclear Information System (INIS)

    Modarres Mosalla, M.M.

    2002-01-01

    Tissue attenuation effect, especially breast and diaphragm can produce artifactual defects in the myocardial perfusion SPECT. Several ways are suggested to minimize such an effect. The aim of this study is evaluation of the effect of supine and prone position on the anterior and inferior left ventricular walls during myocardial perfusion SPECT. 48 patients, 30 men and 18 women, with age of 42-73 years without typical chest pain, <15% probability of coronary artery disease, significant abdominal fat pad, and hypo activity of the inferior wall in supine position were selected. SPECT was repeated in the prone position. 22(73%) male patients and 8(44%) of female patients showed more activity of the anterior wall in the prone position (p<0.01). The anterior wall became hypoactive in 7(23%) of male patients (p<0.01) in the prone position. The anterior wall showed lesser activity in the supine position in 6(33%) of female patients (p<0.01). Although breast attenuation is more common in female, diaphragmatic attenuation can also be troublesome. In these selected women prone position minimized both effects. Prone position in the male patients decreases the attenuation effect of diaphragm significantly but may cause false defect in the anterior wall. Myocardial perfusion SPECT is preferred to be performed in prone position in both sexes, however possibility of anterior wall false defect should be considered

  2. First in vivo magnetic particle imaging of lung perfusion in rats

    Science.gov (United States)

    Zhou, Xinyi Y.; Jeffris, Kenneth E.; Yu, Elaine Y.; Zheng, Bo; Goodwill, Patrick W.; Nahid, Payam; Conolly, Steven M.

    2017-05-01

    Pulmonary embolism (PE), along with the closely related condition of deep vein thrombosis, affect an estimated 600 000 patients in the US per year. Untreated, PE carries a mortality rate of 30%. Because many patients experience mild or non-specific symptoms, imaging studies are necessary for definitive diagnosis of PE. Iodinated CT pulmonary angiography is recommended for most patients, while nuclear medicine-based ventilation/perfusion (V/Q) scans are reserved for patients in whom the use of iodine is contraindicated. Magnetic particle imaging (MPI) is an emerging tracer imaging modality with high image contrast (no tissue background signal) and sensitivity to superparamagnetic iron oxide (SPIO) tracer. Importantly, unlike CT or nuclear medicine, MPI uses no ionizing radiation. Further, MPI is not derived from magnetic resonance imaging (MRI); MPI directly images SPIO tracers via their strong electronic magnetization, enabling deep imaging of anatomy including within the lungs, which is very challenging with MRI. Here, the first high-contrast in vivo MPI lung perfusion images of rats are shown using a novel lung perfusion agent, MAA-SPIOs.

  3. Design and Functional Testing of a Multichamber Perfusion Platform for Three-Dimensional Scaffolds

    Directory of Open Access Journals (Sweden)

    Marco Piola

    2013-01-01

    Full Text Available Perfusion culture systems are widely used in tissue engineering applications for enhancing cell culture viability in the core of three-dimensional scaffolds. In this work, we present a multichamber confined-flow perfusion system, designed to provide a straightforward platform for three-dimensional dynamic cell cultures. The device comprises 6 culture chambers allowing independent and simultaneous experiments in controlled conditions. Each chamber consists of three parts: a housing, a deformable scaffold-holder cartridge, and a 7 mL reservoir, which couples water-tightly with the housing compressing the cartridge. Short-term dynamic cell seeding experiments were carried out with MC3T3-E1 cells seeded into polycaprolactone porous scaffolds. Preliminary results revealed that the application of flow perfusion through the scaffold favored the penetration of the cells to its interior, producing a more homogeneous distribution of cells with respect to dropwise or injection seeding methods. The culture chamber layout was conceived with the aim of simplifying the user operations under laminar flow hood and minimizing the risks for contamination during handling and operation. Furthermore, a compact size, a small number of components, and the use of bayonet couplings ensured a simple, fast, and sterility-promoting assembling. Finally, preliminary in vitro tests proved the efficacy of the system in enhancing cell seeding efficiency, opening the way for further studies addressing long-term scaffold colonization.

  4. MR first pass perfusion of benign and malignant cardiac tumours - significant differences and diagnostic accuracy

    International Nuclear Information System (INIS)

    Bauner, K.U.; Picciolo, M.; Theisen, D.; Sandner, T.A.; Reiser, M.F.; Huber, A.M.; Sourbron, S.; Schmitz, C.

    2012-01-01

    To determine the diagnostic value of magnetic resonance (MR) first pass perfusion in the differentiation of benign and malignant cardiac tumours. 24 patients with cardiac tumours (11 malignant, histopathological correlation present in all cases) were examined using MRI. In addition to morphological sequences a saturation-recovery T1w-GRE technique was implemented for tumour perfusion. The maximum relative signal enhancement (RSE[%]) and the slope of the RSE t -curve (slopeRSE[%/s]) of tumour tissue were assessed. A t-test was used to identify significant differences between benign and malignant tumours. Sensitivities and specificities were calculated for detection of malignant lesions and were compared with the sensitivity and specificity based on solely morphological image assessment. The RSE and slopeRSE of malignant cardiac tumours were significantly higher compared with benign lesions (p < 0.001 and p < 0.001). The calculated sensitivities and specificities of RSE and slopeRSE for identification of malignant lesions were 100% and 84.6% and 100% and 92.3%, respectively with cut-off values of 80% and 6%/s. The sensitivity and specificity for identification of malignant lesions on the basis of morphological imaging alone were 90.9% and 69.2%. With first pass perfusion, malignant cardiac masses can be identified with higher sensitivity and specificity compared with morphological image assessment alone. (orig.)

  5. Improvements in the technique of vascular perfusion-fixation employing a fluorocarbon-containing perfusate and a peristaltic pump controlled by pressure feedback

    DEFF Research Database (Denmark)

    Rostgaard, J; Qvortrup, Klaus; Poulsen, Steen Seier

    1993-01-01

    -fixative is composed of a blood substitute--13.3% oxygenated fluorocarbon FC-75--in 0.05 M cacodylate buffer (pH 7.4) with a 2% glutaraldehyde. The secondary perfusate-fixative is composed of 2% glutaraldehyde in 0.05 M cacodylate buffer (pH 7.4) with 20 mM CaCl2. A double-barrelled, self-holding cannula is used...... to cannulate the heart; the outer and inner barrels of the cannula are connected to the peristaltic pump and to the pressure transducer, respectively. The tissue oxygen tension in the rat is monitored by a subcutaneous oxygen electrode. Measurements showed that tissue hypoxia/anoxia did not develop before...

  6. Hypothermic Machine Perfusion of Kidney Grafts: Which Pressure is Preferred?

    NARCIS (Netherlands)

    Doorschodt, B. M.; Schreinemachers, M. C. J. M.; Behbahani, M.; Florquin, S.; Weis, J.; Staat, M.; Tolba, R. H.

    2011-01-01

    To assess the effect of the perfusion pressure (PP) during machine perfusion (MP) on the preservation quality of kidney grafts, we compared mean PPs of 25 and 30 mmHg using a porcine autotransplantation model. After assessment of the microcirculation, animals underwent left nephrectomy. Thereafter,

  7. Spatio-temporal analysis of blood perfusion by imaging photoplethysmography

    Science.gov (United States)

    Zaunseder, Sebastian; Trumpp, Alexander; Ernst, Hannes; Förster, Michael; Malberg, Hagen

    2018-02-01

    Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements. This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio). Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are influenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points. This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance.

  8. Donepezil: A cause of inadequate muscle relaxation and delayed neuromuscular recovery

    Directory of Open Access Journals (Sweden)

    Alka Bhardwaj

    2011-01-01

    Full Text Available A 74-year-old female with diabetes mellitus type II and Alzheimer′s disease, taking donepezil for 4 months was operated for right modified radical mastectomy under general anesthesia. During the procedure a higher dose of non-depolarizing muscle relaxant was required than those recommended for her age yet the muscle relaxation was inadequate intra-operatively. Residual neuromuscular blockade persisted postoperatively, due to the cumulative effect of large doses of non-depolarizing muscle relaxant, needing post-operative ventilatory assistance. After ruling out other causes of resistance to non-depolarizing muscle relaxants, we concluded that acetylcholinesterase inhibitor donepezil was primarily responsible for inadequate muscle relaxation and delayed post-operative neuromuscular recovery.

  9. Role of Sex and the Environment in Moderating Weight Gain Due to Inadequate Sleep.

    Science.gov (United States)

    Coborn, Jamie E; Houser, Monica M; Perez-Leighton, Claudio E; Teske, Jennifer A

    2017-12-01

    The growing prevalence of obesity, inadequate sleep and sleep disorders together with the negative impact of lack of sleep on overall health highlights the need for therapies targeted towards weight gain due to sleep loss. Sex disparities in obesity and sleep disorders are present; yet, the role of sex is inadequately addressed and thus it is unclear whether sensitivity to sleep disruption differs between men and women. Like sex, environmental factors contribute to the development of obesity and poor sleep. The obesogenic environment is characterized by easy access to palatable foods and a low demand for energy expenditure in daily activities. These and other environmental factors are discussed, as they drive altered sleep or their interaction with food choice and intake can promote obesity. We discuss data that suggest differences in sleep patterns and responses to sleep disruption influence sex disparities in weight gain, and that enviromental disturbances alter sleep and interact with features of the obesogenic environment that together promote obesity.

  10. Brain perfusion imaging with iodinated amines

    International Nuclear Information System (INIS)

    Kung, H.F.

    1989-01-01

    Traditional nuclear medicine brain study using 99m Tc pertechnetate, glucoheptonate or diethlenetriaminepentacetic acid (DTPA) and planar imaging has experienced a significant decline in the past 10 years. This is mainly due to the introduction of X-ray CT and more recently the nuclear magnetic resonance (NMR) imaging, by which detailed morphology of the brain, including the detection of breakdown of the blood-brain barrier, can be obtained. The nuclear medicine brain imaging is only prescribed as a complementary test when X-ray CT is negative or equivocal and clinical suspicion remains. The attention of nuclear medicine brain imaging has been shifted from the detection of the breakdown of the blood-brain barrier to the study of brain function-perfusion, metabolism, and receptor binding, etc. The functional brain imaging provides diagnostic information usually unattainable by other radiological techniques. In this article, the iodinated amines as brain perfusion imaging agents are reviewed. Potential clinical application of these agents is discussed

  11. OCCUPATIONAL ACCIDENTS AS INDICATORS OF INADEQUATE WORK CONDITIONS AND WORK ENVIRONMENT

    OpenAIRE

    Petar Babović

    2009-01-01

    Occupational accidents due to inadequate working conditions and work environment present a major problem in highly industrialised countries, as well as in developing ones. Occupational accidents are a regular and accompanying phenomenon in all human activities and one of the main health related and economic problems in modern societies.The aim of this study is the analysis of the connections of unfavourable working conditions and working environment on occupational accidents. Occurrence of oc...

  12. Global trends in dietary micronutrient supplies and estimated prevalence of inadequate intakes.

    Directory of Open Access Journals (Sweden)

    Ty Beal

    Full Text Available Understanding dietary patterns is vital to reducing the number of people experiencing hunger (about 795 million, micronutrient deficiencies (2 billion, and overweight or obesity (2.1 billion. We characterize global trends in dietary quality by estimating micronutrient density of the food supply, prevalence of inadequate intake of 14 micronutrients, and average prevalence of inadequate intake of these micronutrients for all countries between 1961 and 2011. Over this 50-year period, the estimated prevalence of inadequate intakes of micronutrients has declined in all regions due to increased total production of food and/or micronutrient density. This decline has been particularly strong in East and Southeast Asia and weaker in South Asia and sub-Saharan Africa. Sub-Saharan Africa is the only region where dietary micronutrient density has declined over this 50-year period. At the global level, micronutrients with the lowest levels of adequate estimated intake are calcium, iron, vitamin A, and zinc, but there are strong differences between countries and regions. Fortification has reduced the estimated prevalence of inadequate micronutrient intakes in all low-income regions, except South Asia. The food supply in many countries is still far below energy requirements, which suggests a need to increase the availability and accessibility of nutritious foods. Countries where the food energy supply is adequate show a very large variation in dietary quality, and in many of these countries people would benefit from more diverse diets with a greater proportion of micronutrient-dense foods. Dietary quality can be improved through fortification, biofortification, and agricultural diversification, as well as efforts to improve access to and use of micronutrient-dense foods and nutritional knowledge. Reducing poverty and increasing education, especially of women, are integral to sustainably addressing malnutrition.

  13. Global trends in dietary micronutrient supplies and estimated prevalence of inadequate intakes.

    Science.gov (United States)

    Beal, Ty; Massiot, Eric; Arsenault, Joanne E; Smith, Matthew R; Hijmans, Robert J

    2017-01-01

    Understanding dietary patterns is vital to reducing the number of people experiencing hunger (about 795 million), micronutrient deficiencies (2 billion), and overweight or obesity (2.1 billion). We characterize global trends in dietary quality by estimating micronutrient density of the food supply, prevalence of inadequate intake of 14 micronutrients, and average prevalence of inadequate intake of these micronutrients for all countries between 1961 and 2011. Over this 50-year period, the estimated prevalence of inadequate intakes of micronutrients has declined in all regions due to increased total production of food and/or micronutrient density. This decline has been particularly strong in East and Southeast Asia and weaker in South Asia and sub-Saharan Africa. Sub-Saharan Africa is the only region where dietary micronutrient density has declined over this 50-year period. At the global level, micronutrients with the lowest levels of adequate estimated intake are calcium, iron, vitamin A, and zinc, but there are strong differences between countries and regions. Fortification has reduced the estimated prevalence of inadequate micronutrient intakes in all low-income regions, except South Asia. The food supply in many countries is still far below energy requirements, which suggests a need to increase the availability and accessibility of nutritious foods. Countries where the food energy supply is adequate show a very large variation in dietary quality, and in many of these countries people would benefit from more diverse diets with a greater proportion of micronutrient-dense foods. Dietary quality can be improved through fortification, biofortification, and agricultural diversification, as well as efforts to improve access to and use of micronutrient-dense foods and nutritional knowledge. Reducing poverty and increasing education, especially of women, are integral to sustainably addressing malnutrition.

  14. Cognitive Dissonance, Confirmatory Bias and Inadequate Information Processing: Evidence from Experimental Auctions

    OpenAIRE

    Cao, Ying; Just, David R.; Wansink, Brian

    2014-01-01

    Using psychological terms such as cognitive dissonance and confirmation bias, this study reveals how individual consumers inadequately process (food safety) information, pay limited attention to signals, and make purchase decisions that are bias towards their initial choices. While it is expected that reading extra information about potential risk associated with the food decreases consumers' willingness to pay (WTP), the magnitude of the impact varies across individuals. In general, consumer...

  15. Growth inhibition in rats fed inadequate and incomplete proteins: repercussion on mandibular biomechanics

    OpenAIRE

    Bozzini, Clarisa; Champin, Graciela Monica; Bozzini, Carlos Eduardo Jose; Alippi, Rosa Maria

    2015-01-01

    This study describes the effects of feeding growing rats with a diet containing inadequate and incomplete proteins on both the morphological and the biomechanical properties of the mandible. Female rats aged 30 d were fed freely with one of two diets, control (CD, 301 Cal/100g) and experimental (ED, 359 Cal/100g). CD was a standard laboratory diet, while ED was a synthetic diet containing cornflower supplemented with vitamins and minerals. Both diets had the same physical characteristics. Con...

  16. Inadequate management of pregnancy-associated listeriosis: lessons from four case reports.

    Science.gov (United States)

    Charlier, C; Goffinet, F; Azria, E; Leclercq, A; Lecuit, M

    2014-03-01

    Listeria monocytogenes infection during pregnancy can lead to dramatic fetal or neonatal outcomes. No clinical trial has evaluated treatment options, and retrospective studies of cases are therefore important to define optimal regimens. We report four cases of materno-neonatal listeriosis illustrating inadequate antimicrobial therapy management and discuss recommended treatment options. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

  17. Tissue physiology and the response to heat

    DEFF Research Database (Denmark)

    Horsman, Michael Robert

    2006-01-01

    The most important physiological parameter influencing tissue response to heat is blood flow. At mild hyperthermia temperatures blood perfusion increases in many tumours and this effect is heating time-, temperature- and tumour-dependent. These flow increases can improve tumour oxygenation. When...... physiological effects should occur in normal tissues, such combination therapies must be carefully applied. Heating tumours to higher temperatures typically causes a transient increase in perfusion during heating, followed by vascular collapse which if sufficient will increase tumour necrosis. The speed...... can also be exploited to improve the response to heat. Decreasing blood flow, using transient physiological modifiers or longer acting vascular disrupting agents prior to the initiation of heating, can both increase the accumulation of physical heat in the tumour, as well as increase heat sensitivity...

  18. Stroke prognosis by applying double thresholds on CT-perfusion-brain images

    Science.gov (United States)

    Chokchaitam, Somchart; Santipromwong, Nittaya; Muengtaweepongsa, Sombat

    2013-03-01

    The CT-perfusion image shows information of brain abnormalities such as its size and location. Generally, neurologist diagnoses stroke disease using CT-perfusion images such as Cerebral blood flow (CBF), cerebral blood volume (CBV). In our previous report, we applied threshold technique to divide amount of CBV and CBF into low and high level. Then, their levels are applied to identify normal tissue areas, dead tissue areas (infract core) and blood-cot tissue areas (infract penumbra). However, it's not totally correct, if the same threshold is applied to the whole area (it must depend on size of blood vessel in that area. In this report, we propose double thresholds to divided CBV and CBF into 3 levels: very low, medium and very high levels. Very low and very high levels are definitely implied to bad areas and good areas, respectively. The proposed double thresholds makes stroke prognosis more accurate. The simulation results confirm that our proposed results closed to results defined from neurologist comparing to the conventional results.

  19. Evaluation of blood perfusion in liver cirrhosis by dynamic contrast enhanced computed tomography

    DEFF Research Database (Denmark)

    Andersen, Mette L.; Fallentin, Eva; Lauridsen, Carsten Ammitzbøl

    2017-01-01

    -CT), in patients with varying degrees of cirrhosis categorised by Child Pugh score (CP). We compared the perfusion values and the hepatic perfusion index (HPI) ((AP/AP+PP) x 100) in between the three respective CP groups, to evaluate if AP, PP and HPI correlated with the CP level and hepatic venous pressure...... patients, and C in six patients. The mean values of AP were significantly increased in patients with CP C vs. A+B, (70,4 ml/ vs. 43.1) ml/min/100ml tissue (p=0.0003). Patients with Child Pugh A tended to have higher PP values, 117,7 and Child B+C 105.3 ml/min/100ml tissue, respectively (p=0,44). The HPI...... increased significant with the degree of cirrhosis (mean A 29.6/B 30,96/C 44.9 ml/min/100ml tissue ANOVA p=0,046). Testing for linear regression with PP and HVPG values, the r-values raised with CP score (CP A r=0,137 p=0,049, CP B r=0,314 p=0,215 and CP C r=0,427 p=0,12). We found no correlation between...

  20. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Sidaros, Karam; Gesmar, Henrik

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom....

  1. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, I.K.; Sidaros, Karam; Gesmar, H

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom...

  2. Myocardial perfusion in peripheral Raynaud's phenomenon. Evaluation using stress cardiovascular magnetic resonance.

    Science.gov (United States)

    Mavrogeni, Sophie; Bratis, Konstantinos; Koutsogeorgopoulou, Loukia; Karabela, Georgia; Savropoulos, Efthymios; Katsifis, Gikas; Raftakis, John; Markousis-Mavrogenis, George; Kolovou, Genovefa

    2017-02-01

    Peripheral Raynaud's phenomenon (RP) is either primary (PRP), without any coexisting disease or secondary (SRP), due to connective tissue diseases (CTD). We hypothesized that adenosine stress cardiovascular magnetic resonance (CMR) can assess myocardial perfusion in a population of PRP and SRP. Twenty CTDs, aged 30.6±7.5yrs., 16F/4M, including 9 systemic sclerosis (SSc), 4 systemic lupus erythematosus (SLE), 3 mixed connective tissue disease (MCTD), 2 polymyositis (PM) and 2 rheumatoid arthritis (RA), with SRP, under treatment with calcium blockers, were evaluated by stress CMR and compared with age-sex matched PRP and controls. All RP patients were under treatment with calcium blockers. Stress perfusion CMR was performed by 1.5T system using 140mg/kg/min adenosine for 4min and 0.05mmol/kg Gd-DTPA for first-pass perfusion. A rest perfusion was performed with the same protocol. Late gadolinium enhanced (LGE) images were acquired after another dose of Gd-DTPA. In both PRP, SRP, the myocardial perfusion reserve index (MPRI) was significantly reduced compared with the controls (1.7±0.6 vs 3.5±0.4, p<0.001 and 0.7±0.2 vs 3.5±0.4, p<0.001, respectively). Furthermore, in SRP, MPRI was significantly reduced, compared with PRP (0.7±0.2 vs 1.7±0.6, p<0.001). Subendo-cardial LGE=8.2±1.7 of LV mass was revealed in 1 SLE, 1MCTD and 2 SSc, but in none of PR patients. MPRI reduction is common in both PRP and SRP, but it is more severe in SRP, even if RP patients are under treatment with calcium blockers. Occult fibrosis may coexist with the reduced MPRI in SRP but not in PRP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Microfluidically supported biochip design for culture of endothelial cell layers with improved perfusion conditions.

    Science.gov (United States)

    Raasch, Martin; Rennert, Knut; Jahn, Tobias; Peters, Sven; Henkel, Thomas; Huber, Otmar; Schulz, Ingo; Becker, Holger; Lorkowski, Stefan; Funke, Harald; Mosig, Alexander

    2015-03-02

    Hemodynamic forces generated by the blood flow are of central importance for the function of endothelial cells (ECs), which form a biologically active cellular monolayer in blood vessels and serve as a selective barrier for macromolecular permeability. Mechanical stimulation of the endothelial monolayer induces morphological remodeling in its cytoskeleton. For in vitro studies on EC biology culture devices are desirable that simulate conditions of flow in blood vessels and allow flow-based adhesion/permeability assays under optimal perfusion conditions. With this aim we designed a biochip comprising a perfusable membrane that serves as cell culture platform multi-organ-tissue-flow (MOTiF biochip). This biochip allows an effective supply with nutrition medium, discharge of catabolic cell metabolites and defined application of shear stress to ECs under laminar flow conditions. To characterize EC layers cultured in the MOTiF biochip we investigated cell viability, expression of EC marker proteins and cell adhesion molecules of ECs dynamically cultured under low and high shear stress, and compared them with an endothelial culture in established two-dimensionally perfused flow chambers and under static conditions. We show that ECs cultured in the MOTiF biochip form a tight EC monolayer with increased cellular density, enhanced cell layer thickness, presumably as the result of a rapid and effective adaption to shear stress by remodeling of the cytoskeleton. Moreover, endothelial layers in the MOTiF biochip express higher amounts of EC marker proteins von-Willebrand-factor and PECAM-1. EC layers were highly responsive to stimulation with TNFα as detected at the level of ICAM-1, VCAM-1 and E-selectin expression and modulation of endothelial permeability in response to TNFα/IFNγ treatment under flow conditions. Compared to static and two-dimensionally perfused cell culture condition we consider MOTiF biochips as a valuable tool for studying EC biology in vitro under

  4. Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations☆

    Science.gov (United States)

    Day, P.E.L.; Cleal, J.K.; Lofthouse, E.M.; Goss, V.; Koster, G.; Postle, A.; Jackson, J.M.; Hanson, M.A.; Jackson, A.A.; Lewis, R.M.

    2013-01-01

    Introduction Placental glutamine synthesis has been demonstrated in animals and is thought to increase the availability of this metabolically important amino acid to the fetus. Glutamine is of fundamental importance for cellular replication, cellular function and inter-organ nitrogen transfer. The objective of this study was to investigate the role of glutamate/glutamine metabolism by the isolated perfused human placenta in the provision of glutamine to the fetus. Methods Glutamate metabolism was investigated in the isolated dually perfused human placental cotyledon. U–13C-glutamate was used to investigate the movement of carbon and 15N-leucine to study movement of amino-nitrogen. Labelled amino acids were perfused via maternal or fetal arteries at defined flow rates. The enrichment and concentration of amino acids in the maternal and fetal veins were measured following 5 h of perfusion. Results Glutamate taken up from the maternal and fetal circulations was primarily converted into glutamine the majority of which was released into the maternal circulation. The glutamine transporter SNAT5 was localised to the maternal-facing membrane of the syncytiotrophoblast. Enrichment of 13C or 15N glutamine in placental tissue was lower than in either the maternal or fetal circulation, suggesting metabolic compartmentalisation within the syncytiotrophoblast. Discussion Placental glutamine synthesis may help ensure the placenta's ability to supply this amino acid to the fetus does not become limiting to fetal growth. Glutamine synthesis may also influence placental transport of other amino acids, metabolism, nitrogen flux and cellular regulation. Conclusions Placental glutamine synthesis may therefore be a central mechanism in ensuring that the human fetus receives adequate nutrition and is able to maintain growth. PMID:24183194

  5. CT perfusion mapping of hemodynamic disturbances associated to acute spontaneous intracerebral hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Fainardi, Enrico; Borrelli, Massimo; Saletti, Andrea; Ceruti, Stefano; Tamarozzi, Riccardo [Azienda Ospedaliera Universitaria, Neuroradiology Unit, Department of Neuroscience, Ferrara (Italy); Schivalocchi, Roberta; Cavallo, Michele [Azienda Ospedaliera Universitaria, Neurosurgery Unit, Department of Neuroscience, Ferrara (Italy); Azzini, Cristiano [Azienda Ospedaliera Universitaria, Neurology Unit, Department of Neuroscience, Ferrara (Italy); Chieregato, Arturo [Ospedale M. Bufalini, Neurocritical Care Unit, Cesena (Italy)

    2008-08-15

    We sought to quantify perfusion changes associated to acute spontaneous intracerebral hemorrhage (SICH) by means of computed tomography perfusion (CTP) imaging. We studied 89 patients with supratentorial SICH at admission CT by using CTP scanning obtained within 24 h after symptom onset. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV) and mean transit time (rMTT) levels were measured in four different regions of interest manually outlined on CT scan: (1) hemorrhagic core; (2) perihematomal low-density area; (3) 1 cm rim of normal-appearing brain tissue surrounding the perilesional area; and (4) a mirrored area, including the clot and the perihematomal region, located in the non-lesioned contralateral hemisphere. rCBF, rCBV, and rMTT mean levels showed a centrifugal distribution with a gradual increase from the core to the periphery (p < 0.0001). Perfusion absolute values were indicative of ischemia in hemorrhagic core, oligemia in perihematomal area, and hyperemia in normal-appearing and contralateral areas. Perihematomal rCBF and rCBV mean levels were higher in small ({<=}20 ml) than in large (>20 ml) hematomas (p<0.01 and p <0.02, respectively). Multi-parametric CTP mapping of acute SICH indicates that perfusion values show a progressive improvement from the core to the periphery. In the first 24 h, perihemorrhagic region was hypoperfused with CTP values which were not suggestive of ischemic penumbra destined to survive but more likely indicative of edema formation. These findings also argue for a potential influence of early amounts of bleeding on perihematomal hemodynamic abnormalities. (orig.)

  6. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications

    International Nuclear Information System (INIS)

    Peladeau-Pigeon, M; Coolens, C

    2013-01-01

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  7. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications.

    Science.gov (United States)

    Peladeau-Pigeon, M; Coolens, C

    2013-09-07

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  8. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications

    Science.gov (United States)

    Peladeau-Pigeon, M.; Coolens, C.

    2013-09-01

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  9. Inadequate vocal hygiene habits associated with the presence of self-reported voice symptoms in telemarketers.

    Science.gov (United States)

    Fuentes-López, Eduardo; Fuente, Adrian; Contreras, Karem V

    2017-12-18

    The aim of this study is to determine possible associations between vocal hygiene habits and self-reported vocal symptoms in telemarketers. A cross-sectional study that included 79 operators from call centres in Chile was carried out. Their vocal hygiene habits and self-reported symptoms were investigated using a validated and reliable questionnaire created for the purposes of this study. Forty-five percent of telemarketers reported having one or more vocal symptoms. Among them, 16.46% reported that their voices tense up when talking and 10.13% needed to clear their throat to make their voices clearer. Five percent mentioned that they always talk without taking a break and 40.51% reported using their voices in noisy environments. The number of working hours per day and inadequate vocal hygiene habits were associated with the presence of self-reported symptoms. Additionally, an interaction between the use of the voice in noisy environments and not taking breaks during the day was observed. Finally, the frequency of inadequate vocal hygiene habits was associated with the number of symptoms reported. Using the voice in noisy environments and talking without taking breaks were both associated with the presence of specific vocal symptoms. This study provides some evidence about the interaction between these two inadequate vocal hygiene habits that potentiates vocal symptoms.

  10. Managing inadequate responses to frontline treatment of chronic myeloid leukemia: a case-based review.

    Science.gov (United States)

    Bixby, Dale L

    2013-05-01

    The tyrosine kinase inhibitors (TKIs) imatinib, nilotinib, and dasatinib are the standard of care for treating patients with newly diagnosed chronic-phase chronic myeloid leukemia (CML). Compared with interferon-based treatment, the previous standard of care, imatinib is associated with significantly higher cytogenetic response rates and prolonged overall survival. Nilotinib and dasatinib, both newer and more potent TKIs, significantly improve cytogenetic and molecular response rates compared with imatinib. Despite significant advances in CML treatment enabled by the TKIs, a fraction of patients who receive frontline treatment with a TKI demonstrate inadequate response. The reasons for this vary, but in many cases, inadequate response can be attributed to non-adherence to the treatment regimen, intolerance to the drug, intrinsic or acquired resistance to the drug, or a combination of reasons. More often than not, strategies to improve response necessitate a change in treatment plan, either a dose adjustment or a switch to an alternate drug, particularly in the case of drug intolerance or drug resistance. Improved physician-patient communication and patient education are effective strategies to address issues relating to adherence and intolerance. Because inadequate response to TKI treatment correlates with poor long-term outcomes, it is imperative that patients who experience intolerance or who fail to achieve appropriate responses are carefully evaluated so that appropriate treatment modifications can be made to maximize the likelihood of positive long-term outcome. Copyright © 2012. Published by Elsevier Ltd.

  11. Predictors of inadequate initial echocardiography in suspected Kawasaki disease: Criteria for sedation.

    Science.gov (United States)

    Lorenzoni, Raymond P; Choi, Jaeun; Choueiter, Nadine F; Munjal, Iona M; Katyal, Chhavi; Stern, Kenan W D

    2018-03-09

    Kawasaki disease is the primary cause of acquired pediatric heart disease in developed nations. Timely diagnosis of Kawasaki disease incorporates transthoracic echocardiography for visualization of the coronary arteries. Sedation improves this visualization, but not without risks and resource utilization. To identify potential sedation criteria for suspected Kawasaki disease, we analyzed factors associated with diagnostically inadequate initial transthoracic echocardiography performed without sedation. This retrospective review of patients Kawasaki disease from 2009 to 2015 occurred at a medium-sized urban children's hospital. The primary outcome was diagnostically inadequate transthoracic echocardiography without sedation due to poor visualization of the coronary arteries, determined by review of clinical records. The associations of the primary outcome with demographics, Kawasaki disease type, laboratory data, fever, and anti