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Sample records for radionuclide ischemic perfusion

  1. Radionuclide imaging in ischemic stroke.

    PubMed

    Heiss, Wolf-Dieter

    2014-11-01

    Ischemic stroke is caused by interruption or significant impairment of blood supply to the brain, which leads to a cascade of metabolic and molecular alterations resulting in functional disturbance and morphologic damage. The changes in regional cerebral blood flow and regional metabolism can be assessed by radionuclide imaging, especially SPECT and PET. SPECT and PET have broadened our understanding of flow and metabolic thresholds critical for maintenance of brain function and morphology: PET was essential in the transfer of the concept of the penumbra to clinical stroke and thereby had a great impact on developing treatment strategies. Receptor ligands can be applied as early markers of irreversible neuronal damage and can predict the size of the final infarcts, which is important for decisions on invasive therapy in large ("malignant") infarction. With SPECT and PET, the reserve capacity of the blood supply can be tested in obstructive arteriosclerosis, which is essential for planning interventions. The effect of a stroke on surrounding and contralateral primarily unaffected tissue can be investigated, helping to understand symptoms caused by disturbance in functional networks. Activation studies are useful to demonstrate alternative pathways to compensate for lesions and to test the effect of rehabilitative therapy. Radioisotope studies help to detect neuroinflammation and its effect on extension of tissue damage. Despite the limitations of broad clinical application of radionuclide imaging, this technology has a great impact on research in cerebrovascular diseases and still has various applications in the management of stroke.

  2. Luxury perfusion following anterior ischemic optic neuropathy.

    PubMed

    Friedland, S; Winterkorn, J M; Burde, R M

    1996-09-01

    We present five patients who developed luxury perfusion following anterior ischemic optic neuropathy in whom fluorescein angiography was misinterpreted as "capillary hemangioma" or neovascularization of the disc. In each case, the segment of disc hyperemia corresponded to a spared region of visual field. Luxury perfusion represents a reparative autoregulatory reaction to ischemia.

  3. Prevalence and significance of reversible radionuclide ischemic perfusion defects in symptomatic aortic valve disease patients with or without concomitant coronary disease

    SciTech Connect

    Pfisterer, M.; Mueller-Brand, J.; Bruendler, H.; Cueni, T.

    1982-01-01

    To determine the prevalence and significance of exercise-induced localized perfusion defects in symptomatic patients with aortic valve disease, thallium-201 rest and exercise studies were performed in a consecutive series of 29 such patients prior to left heart catheterization with coronary arteriography. Eight patients had repeat studies after aortic valve replacement. Twelve of 17 patients with predominant aortic regurgitation (AR) had distinct LV apical defects during exercise despite normal coronary arteries, while 10 of 12 patients with aortic valve disease and associated coronary artery disease (CAD) had localized perfusion defects in LV areas other than the apex. In patients with AR, reversible apical perfusion defects can occur without CAD; these apical defects are probably a reflection of severe LV volume overload in AR. LV perfusion defects in areas other than the apex are specific for CAD in aortic valve disease, and concomitant CAD may not provoke regional LV perfusion deficits in aortic stenosis patients with severe LV hypertrophy.

  4. Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy

    SciTech Connect

    Eichhorn, E.J.; Kosinski, E.J.; Lewis, S.M.; Hill, T.C.; Emond, L.H.; Leland, O.S.

    1988-11-01

    To determine noninvasively the etiology of left ventricular (LV) dysfunction, 22 patients with a diagnosis of cardiomyopathy determined via cardiac catheterization and 5 normal control subjects underwent radionuclide ventriculography and intravenous dipyridamole-thallium-201 perfusion scanning. Both ischemically and nonischemically induced LV dysfunction had comparable global LV ejection fractions (24 +/- 6 vs 23 +/- 8%, respectively) and extent of segmental wall motion abnormalities. Right ventricular ejection fraction was significantly better in the group with an ischemic etiology of LV dysfunction (41 +/- 26 vs 13 +/- 10%, p less than 0.005) but significant group overlap was present. However, computer-assisted analysis of dipyridamole-thallium-201 myocardial perfusion scanning demonstrated more homogeneous myocardial perfusion in idiopathic cardiomyopathy (mean perfusion defect 25 +/- 11 vs 6 +/- 6%, p less than 0.001) and successfully predicted the correct etiology of LV dysfunction in 20 of 22 (91%) patients.

  5. New Trends in Radionuclide Myocardial Perfusion Imaging

    PubMed Central

    Hung, Guang-Uei; Wang, Yuh-Feng; Su, Hung-Yi; Hsieh, Te-Chun; Ko, Chi-Lun; Yen, Ruoh-Fang

    2016-01-01

    Radionuclide myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) has been widely used clinically as one of the major functional imaging modalities for patients with coronary artery disease (CAD) for decades. Ample evidence has supported the use of MPI as a useful and important tool in the diagnosis, risk stratification and treatment planning for CAD. Although popular in the United States, MPI has become the most frequently used imaging modality among all nuclear medicine tests in Taiwan. However, it should be acknowledged that MPI SPECT does have its limitations. These include false-positive results due to certain artifacts, false-negative due to balanced ischemia, complexity and adverse reaction arising from current pharmacological stressors, time consuming nature of the imaging procedure, no blood flow quantitation and relatively high radiation exposure. The purpose of this article was to review the recent trends in nuclear cardiology, including the utilization of positron emission tomography (PET) for MPI, new stressor, new SPECT camera with higher resolution and higher sensitivity, dynamic SPECT protocol for blood flow quantitation, new software of phase analysis for evaluation of LV dyssynchrony, and measures utilized for reducing radiation exposure of MPI. PMID:27122946

  6. Perfusion Angiography in Acute Ischemic Stroke

    PubMed Central

    Liebeskind, David S.

    2016-01-01

    Visualization and quantification of blood flow are essential for the diagnosis and treatment evaluation of cerebrovascular diseases. For rapid imaging of the cerebrovasculature, digital subtraction angiography (DSA) remains the gold standard as it offers high spatial resolution. This paper lays out a methodological framework, named perfusion angiography, for the quantitative analysis and visualization of blood flow parameters from DSA images. The parameters, including cerebral blood flow (CBF) and cerebral blood volume (CBV), mean transit time (MTT), time-to-peak (TTP), and Tmax, are computed using a bolus tracking method based on the deconvolution of the time-density curve on a pixel-by-pixel basis. The method is tested on 66 acute ischemic stroke patients treated with thrombectomy and/or tissue plasminogen activator (tPA) and also evaluated on an estimation task with known ground truth. This novel imaging tool provides unique insights into flow mechanisms that cannot be observed directly in DSA sequences and might be used to evaluate the impact of endovascular interventions more precisely. PMID:27446232

  7. Machine Perfusion Enhances Hepatocyte Isolation Yields From Ischemic Livers

    PubMed Central

    Izamis, Maria-Louisa; Perk, Sinem; Calhoun, Candice; Uygun, Korkut; Yarmush, Martin L.; Berthiaume, François

    2015-01-01

    Background High-quality human hepatocytes form the basis of drug safety and efficacy tests, cell-based therapies, and bridge-to-transplantation devices. Presently the only supply of cells derives from an inadequate pool of suboptimal disqualified donor livers. Here we evaluated whether machine perfusion could ameliorate ischemic injury that many of these livers experience prior to hepatocyte isolation. Methods Non-heparinized female Lewis rat livers were exposed to an hour of warm ischemia (34°C) and then perfused for 3 hours. Five different perfusion conditions that utilized the cell isolation apparatus were investigated, namely: (1) modified Williams Medium E and (2) Lifor, both with active oxygenation (95%O2/5%CO2), as well as (3) Lifor passively oxygenated with ambient air (21%O2/0.04%CO2), all at ambient temperatures (20±2°C). At hypothermic temperatures (5±1°C) and under passive oxygenation were (4) University of Wisconsin solution (UW) and (5) Vasosol. Negative and positive control groups comprised livers that had ischemia (WI) and livers that did not (Fresh) prior to cell isolation, respectively. Results Fresh livers yielded 32±9 million cells/g liver while an hour of ischemia reduced the cell yield to 1.6±0.6 million cells/g liver. Oxygenated Williams medium E and Lifor recovered yields of 39±11 and 31±2.3 million cells/g liver, respectively. The passively oxygenated groups produced 15±7 (Lifor), 13±7 (Vasosol), and 10±6 (UW) million cells/g liver. Oxygenated Williams Medium E was most effective at sustaining pH values, avoiding the accumulation of lactate, minimizing edematous weight gain and producing bile during perfusion. Conclusions Machine perfusion results in a dramatic increase in cell yields from livers that have had up to an hour of warm ischemia, but perfusate choice significantly impacts the extent of recovery. Oxygenated Williams Medium E at room temperature is superior to Lifor, UW and Vasosol, largely facilitated by its high

  8. SIMPLE MACHINE PERFUSION SIGNIFICANTLY ENHANCES HEPATOCYTE YIELDS OF ISCHEMIC AND FRESH RAT LIVERS.

    PubMed

    Izamis, Maria-Louisa; Calhoun, Candice; Uygun, Basak E; Guzzardi, Maria Angela; Price, Gavrielle; Luitje, Martha; Saeidi, Nima; Yarmush, Martin L; Uygun, Korkut

    2013-01-01

    The scarcity of viable hepatocytes is a significant bottleneck in cell transplantation, drug discovery, toxicology, tissue engineering, and bioartificial assist devices, where trillions of high-functioning hepatocytes are needed annually. We took the novel approach of using machine perfusion to maximize cell recovery, specifically from uncontrolled cardiac death donors, the largest source of disqualified donor organs. In a rat model, we developed a simple 3 hour room temperature (20±2°C) machine perfusion protocol to treat non-premedicated livers exposed to 1 hour of warm (34°C) ischemia. Treated ischemic livers were compared to fresh, fresh-treated and untreated ischemic livers using viable hepatocyte yields and in vitro performance as quantitative endpoints. Perfusion treatment resulted in both a 25-fold increase in viable hepatocytes from ischemic livers, and a 40% increase from fresh livers. While cell morphology and function in suspension and plate cultures of untreated warm ischemic cells was significantly impaired, treated warm ischemic cells were indistinguishable from fresh hepatocytes. Further, a strong linear correlation between tissue ATP and cell yield enabled accurate evaluation of the extent of perfusion recovery. Maximal recovery of warm ischemic liver ATP content appears to be correlated with optimal flow through the microvasculature. These data demonstrate that the inclusion of a simple perfusion-preconditioning step can significantly increase the efficiency of functional hepatocyte yields and the number of donor livers that can be gainfully utilized.

  9. Simple Machine Perfusion Significantly Enhances Hepatocyte Yields of Ischemic and Fresh Rat Livers

    PubMed Central

    Izamis, Maria-Louisa; Calhoun, Candice; Uygun, Basak E.; Guzzardi, Maria Angela; Price, Gavrielle; Luitje, Martha; Saeidi, Nima; Yarmush, Martin L.; Uygun, Korkut

    2013-01-01

    The scarcity of viable hepatocytes is a significant bottleneck in cell transplantation, drug discovery, toxicology, tissue engineering, and bioartificial assist devices, where trillions of high-functioning hepatocytes are needed annually. We took the novel approach of using machine perfusion to maximize cell recovery, specifically from uncontrolled cardiac death donors, the largest source of disqualified donor organs. In a rat model, we developed a simple 3-h room temperature (20 ± 2°C) machine perfusion protocol to treat nonpremedicated livers exposed to 1 h of warm (34°C) ischemia. Treated ischemic livers were compared to fresh, fresh-treated, and untreated ischemic livers using viable hepatocyte yields and in vitro performance as quantitative endpoints. Perfusion treatment resulted in both a 25-fold increase in viable hepatocytes from ischemic livers and a 40% increase from fresh livers. While cell morphology and function in suspension and plate cultures of untreated warm ischemic cells was significantly impaired, treated warm ischemic cells were indistinguishable from fresh hepatocytes. Furthermore, a strong linear correlation between tissue ATP and cell yield enabled accurate evaluation of the extent of perfusion recovery. Maximal recovery of warm ischemic liver ATP content appears to be correlated with optimal flow through the microvasculature. These data demonstrate that the inclusion of a simple perfusion-preconditioning step can significantly increase the efficiency of functional hepatocyte yields and the number of donor livers that can be gainfully utilized. PMID:25431743

  10. Magnetic resonance imaging of luxury perfusion of the optic nerve head in anterior ischemic optic neuropathy.

    PubMed

    Yovel, Oren S; Katz, Miriam; Leiba, Hana

    2012-09-01

    A 49-year-old woman with painless reduction in visual acuity in her left eye was found to have nonarteritic anterior ischemic optic neuropathy (NAION). Fluorescein angiography revealed optic disc capillary leakage consistent with "luxury perfusion." Contrast-enhanced FLAIR magnetic resonance imaging (MRI) showed marked enhancement of the left optic disc. Resolution of the optic disc edema and the MRI abnormalities followed a similar time course. This report appears unique in documenting the MRI findings of luxury perfusion in NAION.

  11. [Preservation of kidneys with ischemic injury using hypothermic storage and mechanical prolonged perfusion].

    PubMed

    Wienand, P; Grundmann, R; Bischoff, A; Pichlmaier, H

    1978-01-01

    Dog kidneys were flushed and stored in Collins (n = 30) and Sacks (n = 32) solution under hypothermia. These results were compared with those gained by mechanical perfusion (n = 21). Before preservation, the kidneys were subjected to 15 - 60 min of warm ischemia then stored for 12 - 24 h. It was concluded that 12-h preservation time after 15-min ischemic injury was the limit of hypothermic storage preservation. Sacks' solution gave better results than Collins' solution as regards the immediate function after transplantation. In contrast, mechanical perfusion was well tolerated for 24-h preservation time after a warm ischemia of 30 min. In case of warm ischemic damage, mechanical perfusion should be preferred to hypothermic storage.

  12. [CT perfusion for assessment of brain stem ischemic lesions].

    PubMed

    Saifullina, E I; Iksanova, G R

    2007-01-01

    Modern neurovisualization modalities - CT and MRI with cerebral circulation assessment was used for diagnosis of cerebrovascular disturbances in patients admitted to the Emergency Care Hospital of Ufa. CT and MRI perfusion methods appeared to be highly effective both in diagnosis and treatment efficacy monitoring of acute stroke.

  13. [An evaluation of ischemic stroke using dynamic contrast enhanced perfusion MRI].

    PubMed

    Yamaguchi, H; Igarashi, H; Katayama, Y; Terashi, A

    1998-04-01

    Thrombolytic therapy during the hyperacute stage is important for salvaging dying cerebral tissue. To date, however, accurate non-invasive assessment of an ischemic lesion during the hyperacute stage has not been possible. Perfusion MRI may be the key to the quick diagnosis of ischemic lesions. To assess the feasibility of dynamic contrast enhanced perfusion MRI, echo planar imaging was performed in 10 patients with ischemic stroke. The relative cerebral blood volume (rCBV), mean transit time (MTT), and relative cerebral blood flow(rCBF) were measured based on moment analysis and the gamma variate method. These measurements, however, are not suitable for the detection of cerebral ischemia during the hyperacute stage. Therefore, we additionally studied the changes in a concentration curve (time-delta R* curve) of Gd-DTPA, injected into the median vein of the forearm. From the curve the SUM (delta R*) time to peak and the delta R* peak, which may be calculated quickly, were determined and were compared to rCBV, MTT, and rCBF, respectively. The rCBV and the rCBF in the ischemic regions were less than those in the contralateral healthy regions (p < 0.05), and the MTT in the ischemic regions was longer than that in the contralateral healthy regions (p < 0.05). Additionally, SUM (delta R*) and the delta R* peak in the ischemic regions were less, and the time to peak in the ischemic regions was longer than the value in the contralateral healthy regions (p < 0.05), correlating well to the rCBV, rCBF, and MTT measurements. Also, images of these parameters, depicting the ischemic lesion earlier than conventional T2 weighted images, can be easily made by using an MRI console. These results suggest that the SUM (delta R*), time to peak and the delta R* peak images calculated with dynamic contrast enhanced perfusion MRI may be one of the best techniques for the detection of cerebral ischemic lesions during the hyperacute stage.

  14. Effect of Extended CT Perfusion Acquisition Time on Ischemic Core and Penumbra Volume Estimation in Patients with Acute Ischemic Stroke due to a Large Vessel Occlusion

    PubMed Central

    Borst, Jordi; Marquering, Henk A.; Beenen, Ludo F. M.; Berkhemer, Olvert A.; Dankbaar, Jan Willem; Riordan, Alan J.; Majoie, Charles B. L. M.

    2015-01-01

    Background and Purpose It has been suggested that CT Perfusion acquisition times <60 seconds are too short to capture the complete in and out-wash of contrast in the tissue, resulting in incomplete time attenuation curves. Yet, these short acquisitions times are not uncommon in clinical practice. The purpose of this study was to investigate the occurrence of time attenuation curve truncation in 48 seconds CT Perfusion acquisition and to quantify its effect on ischemic core and penumbra estimation in patients with acute ischemic stroke due to a proximal intracranial arterial occlusion of the anterior circulation. Materials and Methods We analyzed CT Perfusion data with 48 seconds and extended acquisition times, assuring full time attenuation curves, of 36 patients. Time attenuation curves were classified as complete or truncated. Ischemic core and penumbra volumes resulting from both data sets were compared by median paired differences and interquartile ranges. Controlled experiments were performed using a digital CT Perfusion phantom to investigate the effect of time attenuation curve truncation on ischemic core and penumbra estimation. Results In 48 seconds acquisition data, truncation was observed in 24 (67%) cases for the time attenuation curves in the ischemic core, in 2 cases for the arterial input function and in 5 cases for the venous output function. Analysis of extended data resulted in smaller ischemic cores and larger penumbras with a median difference of 13.2 (IQR: 4.3–26.0)ml (P<0.001) and; 12.4 (IQR: 4.1–25.7)ml (P<0.001), respectively. The phantom data showed increasing ischemic core overestimation with increasing tissue time attenuation curve truncation. Conclusions Truncation is common in patients with large vessel occlusion and results in repartitioning of the area of hypoperfusion into larger ischemic core and smaller penumbra estimations. Phantom experiments confirmed that truncation results in overestimation of the ischemic core. PMID

  15. Automated CT Perfusion for Ischemic Core Volume Prediction in Tandem Anterior Circulation Occlusions

    PubMed Central

    Haussen, Diogo C.; Dehkharghani, Seena; Grigoryan, Mikayel; Bowen, Meredith; Rebello, Leticia C.; Nogueira, Raul G.

    2016-01-01

    Background/Aim CT perfusion (CTP) predicts ischemic core volumes in acute ischemic stroke (AIS); however, assumptions made within the pharmacokinetic model may engender errors by the presence of tracer delay or dispersion. We aimed to evaluate the impact of hemodynamic disturbance due to extracranial anterior circulation occlusions upon the accuracy of ischemic core volume estimation with an automated perfusion analysis tool (RAPID) among AIS patients with large-vessel occlusions. Methods A prospectively collected, interventional database was retrospectively reviewed for all cases of endovascular treatment of AIS between September 2010 and March 2015 for patients with anterior circulation occlusions with baseline CTP and full reperfusion (mTICI3). Results Out of 685 treated patients, 114 fit the inclusion criteria. Comparison between tandem (n = 21) and nontandem groups (n = 93) revealed similar baseline ischemic core (20 ± 19 vs. 19 ± 25 cm3; p = 0.8), Tmax >6 s (175 ± 109 vs. 162 ± 118 cm3; p = 0.6), Tmax >10 s (90 ± 84 vs. 90 ± 91 cm3; p = 0.9), and final infarct volumes (45 ± 47 vs. 37 ± 45 cm3; p = 0.5). Baseline core volumes were found to correlate with final infarct volumes for the tandem (r = 0.49; p = 0.02) and nontandem (r = 0.44; p < 0.01) groups. The mean absolute difference between estimated core and final infarct volume was similar between patients with and those without (24 ± 41 vs. 17 ± 41 cm3; p = 0.5) tandem lesions. Conclusions The prediction of baseline ischemic core volumes through an optimized CTP analysis employing rigorous normalization, thresholding, and voxel-wise analysis is not significantly influenced by the presence of underlying extracranial carotid steno-occlusive disease in large-vessel AIS. PMID:27610125

  16. ECHOCARDIOGRAPHIC EVALUATION OF THE EFFECTS OF STEM CELL THERAPY ON PERFUSION AND FUNCTION IN ISCHEMIC CARDIOMYOPATHY

    PubMed Central

    Inaba, Yoichi; Davidson, Brian P.; Kim, Sajeevani; Liu, Ya Ni; Packwood, William; Belcik, Todd; Xie, Aris; Lindner, Jonathan R.

    2013-01-01

    BACKGROUND Small animal models of ischemic left ventricular (LV) dysfunction are important for the pre-clinical optimization of stem cell therapy. We hypothesized that temporal changes in LV function and regional perfusion after cell therapy can be assessed in mice using echocardiographic imaging. METHODS Wild-type mice (n=25) were studied 7 and 28 days after permanent ligation of the left anterior descending artery. Animals were randomized to receive closed-chest ultrasound-guided intramyocardial delivery of saline (n=13) or 5×105 multipotential adult progenitor cells (MAPC) (n=12) at day 7. Left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volume, left ventricular ejection fraction (LVEF), and stroke volume were measured by high-frequency echocardiography. Multiplanar assessment of perfusion and defect area size were made by myocardial contrast echocardiography (MCE). RESULTS Between day 7 and 28, MAPC-treated animals had a 40–50% reduction in defect size (p<0.001) and a 20–30% increase in total perfusion (p<0.01). Perfusion did not change in non-treated controls. Both LVEDV and LVESV increased between day 7 and 28 in both groups, however LVESV increased to a lesser degree in MAPC-treated versus control mice (+4.2±7.9 vs +19.2±22.0 μL, p<0.05). LVEF increased in the MAPC-treated mice and decreased in control mice (+3.0±4.3 vs −5.6±5.9 %, p<0.01). There was a significant linear relation between the change in LVEF and the change in either defect area size or total perfusion. CONCLUSIONS High-frequency echocardiography and MCE in murine models of ischemic LV dysfunction can be used to assess the response to stem cell therapy and to characterize the relationship between spatial flow, ventricular function and ventricular remodeling. PMID:24315764

  17. Clinical Use of CT Perfusion For Diagnosis and Prediction of Lesion Growth in Acute Ischemic Stroke

    PubMed Central

    Huisa, Branko N; Neil, William P; Schrader, Ronald; Maya, Marcel; Pereira, Benedict; Bruce, Nhu T; Lyden, Patrick D

    2012-01-01

    Background and Purpose CT perfusion (CTP) mapping in research centers correlates well with diffusion weighted imaging (DWI) lesions and may accurately differentiate the infarct core from ischemic penumbra. The value of CTP in real-world clinical practice has not been fully established. We investigated the yield of CTP– derived cerebral blood volume (CBV) and mean transient time (MTT) for the detection of cerebral ischemia and ischemic penumbra in a sample of acute ischemic stroke (AIS) patients. Methods We studied 165 patients with initial clinical symptoms suggestive of AIS. All patients had an initial non-contrast head CT, CT Perfusion (CTP), CT angiogram (CTA) and follow up brain MRI. The obtained perfusion images were used for image processing. CBV, MTT and DWI lesion volumes were visually estimated and manually traced. Statistical analysis was done using R-2.14.and SAS 9.1. Results All normal DWI sequences had normal CBV and MTT studies (N=89). Seventy-three patients had acute DWI lesions. CBV was abnormal in 23.3% and MTT was abnormal in 42.5% of these patients. There was a high specificity (91.8%)but poor sensitivity (40.0%) for MTT maps predicting positive DWI. Spearman correlation was significant between MTT and DWI lesions (ρ=0.66, p>0.0001) only for abnormal MTT and DWI lesions>0cc. CBV lesions did not correlate with final DWI. Conclusions In real-world use, acute imaging with CTP did not predict stroke or DWI lesions with sufficient accuracy. Our findings argue against the use of CTP for screening AIS patients until real-world implementations match the accuracy reported from specialized research centers. PMID:23253533

  18. Intravenous thrombolysis in acute ischemic stroke patients with negative CT perfusion: a case series

    PubMed Central

    Mehra, Ratnesh; Qahwash, Omar; Richards, Boyd; Fessler, Richard D

    2014-01-01

    Background Computed tomography perfusion (CTP) is a commonly used modality of neurophysiologic imaging to aid the selection of acute ischemic stroke patients for neuroendovascular intervention by identifying the presence of penumbra versus infarcted brain tissue. However many patients present with evidence of cerebral ischemia with normal CTP, and in that case, should intravenous thrombolytics be given? Purpose To demonstrate if tissue-type plasminogen activator (tPA)-eligible stroke patients without perfusion defects demonstrated on CTP would benefit from administration of intravenous thrombolytics. Material and Methods We retrospectively identified patients presenting with acute ischemic symptoms who received intravenous tPA (IV-tPA) from January to June 2012 without a perfusion defect on CTP. Clinical and radiographic findings including the NIHSS at presentation, 24 h, and at discharge, symptomatic and asymptomatic hemorrhagic transformation, and the modified Rankin score at 30 days were collected. A reduction of NIHSS of greater than 4 points or resolution of symptoms was considered significant. Results Seventeen patients were identified with a mean NIHSS of 8.2 prior to administration of intravenous thrombolytics, 3.5 after 24 h, and 2.5 at discharge. Among them, 13 patients had significant improvement of NIHSS with a mean reduction of 6.15 points at 24 h. One patient initially improved but had delayed hemorrhagic transformation and died. Two patients had improvement in NIHSS but were not significant and two patients had increased in NIHSS at 24 h, although one eventually improved at discharge. There was no asymptomatic hemorrhagic transformation. Mean mRS at 3 months is 1.76. Conclusion The failure to identify a perfusion deficit by CTP should not be used as a contraindication for intravenous thrombolytics. Criteria for administration of intravenous thrombolytics should still be based on time from symptom onset as previously published by NINDS. PMID

  19. Radionuclide imaging of myocardial perfusion and viability in assessment of acute myocardial infarction

    SciTech Connect

    Berman, D.S.; Kiat, H.; Maddahi, J.; Shah, P.K.

    1989-07-18

    Technical advances in radionuclide imaging have important implications for the management of patients with acute myocardial infarction. Single-photon emission computerized tomography with thallium 201 (TI-201) offers greater accuracy than planar imaging in detecting, localizing and sizing myocardial perfusion defects. Use of single-photon emission computerized tomography with TI-201 should allow for a more accurate assessment of prognosis after myocardial infarction. A new radiopharmaceutical, technetium 99-m methoxyisobutyl isonitrile, provides a number of advantages over TI-201, including higher quality images, lack of redistribution, and the ability to assess first-pass ventricular function. Applications of TI-201 and technetium 99-m methoxyisobutyl isonitrile include assessment of arterial patency and myocardial salvage immediately after thrombolytic therapy, detection of resting ischemia after thrombolytic therapy, targeting of subsets of patients for further intervention, and predischarge assessment to predict the future course of patients after an acute myocardial infarction.

  20. EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision.

    PubMed

    Verberne, Hein J; Acampa, Wanda; Anagnostopoulos, Constantinos; Ballinger, Jim; Bengel, Frank; De Bondt, Pieter; Buechel, Ronny R; Cuocolo, Alberto; van Eck-Smit, Berthe L F; Flotats, Albert; Hacker, Marcus; Hindorf, Cecilia; Kaufmann, Philip A; Lindner, Oliver; Ljungberg, Michael; Lonsdale, Markus; Manrique, Alain; Minarik, David; Scholte, Arthur J H A; Slart, Riemer H J A; Trägårdh, Elin; de Wit, Tim C; Hesse, Birger

    2015-11-01

    Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf .

  1. End-ischemic machine perfusion reduces bile duct injury in donation after circulatory death rat donor livers independent of the machine perfusion temperature.

    PubMed

    Westerkamp, Andrie C; Mahboub, Paria; Meyer, Sophie L; Hottenrott, Maximilia; Ottens, Petra J; Wiersema-Buist, Janneke; Gouw, Annette S H; Lisman, Ton; Leuvenink, Henri G D; Porte, Robert J

    2015-10-01

    A short period of oxygenated machine perfusion (MP) after static cold storage (SCS) may reduce biliary injury in donation after cardiac death (DCD) donor livers. However, the ideal perfusion temperature for protection of the bile ducts is unknown. In this study, the optimal perfusion temperature for protection of the bile ducts was assessed. DCD rat livers were preserved by SCS for 6 hours. Thereafter, 1 hour of oxygenated MP was performed using either hypothermic machine perfusion, subnormothermic machine perfusion, or with controlled oxygenated rewarming (COR) conditions. Subsequently, graft and bile duct viability were assessed during 2 hours of normothermic ex situ reperfusion. In the MP study groups, lower levels of transaminases, lactate dehydrogenase (LDH), and thiobarbituric acid reactive substances were measured compared to SCS. In parallel, mitochondrial oxygen consumption and adenosine triphosphate (ATP) production were significantly higher in the MP groups. Biomarkers of biliary function, including bile production, biliary bicarbonate concentration, and pH, were significantly higher in the MP groups, whereas biomarkers of biliary epithelial injury (biliary gamma-glutamyltransferase [GGT] and LDH), were significantly lower in MP preserved livers. Histological analysis revealed less injury of large bile duct epithelium in the MP groups compared to SCS. In conclusion, compared to SCS, end-ischemic oxygenated MP of DCD livers provides better preservation of biliary epithelial function and morphology, independent of the temperature at which MP is performed. End-ischemic oxygenated MP could reduce biliary injury after DCD liver transplantation.

  2. 'Luxury perfusion syndrome' in a patient with reversible ischemic neurological deficits.

    PubMed

    Banzo, J; Morales, F; Abós, M D; Pascual, L F; Prats, E; Teijeiro, J

    1983-01-01

    A 28-year-old man was admitted to the hospital with difficulty in speech and motor weakness of the right arm of sudden onset. Twelve years previously a grade I oligodendroglioma had been removed. The CT scan showed a low density area without enhancement in the left frontal region that appeared to communicate with the left lateral ventricle. An increased flow through the left middle cerebral-artery and a focal avascular area in the left hemisphere was noted during a dynamic study by angioscintigraphy. A radionuclide cerebral control study showed reduced flow through the left middle cerebral artery. The patient was discharged 25 days after admission with the diagnosis of (1) reversible ischemic neurological deficits associated a hyperperfusion and (2) porencephaly.

  3. Detection of ischemic penumbra using combined perfusion and T2* oxygen challenge imaging

    PubMed Central

    Robertson, Craig A; McCabe, Christopher; Lopez-Gonzalez, M Rosario; Deuchar, Graeme A; Dani, Krishna; Holmes, William M; Muir, Keith W; Santosh, Celestine; Macrae, I Mhairi

    2015-01-01

    Background Acute ischemic stroke is common and disabling, but there remains a paucity of acute treatment options and available treatment (thrombolysis) is underutilized. Advanced brain imaging, designed to identify viable hypoperfused tissue (penumbra), could target treatment to a wider population. Existing magnetic resonance imaging and computed tomography-based technologies are not widely used pending validation in ongoing clinical trials. T2* oxygen challenge magnetic resonance imaging, by providing a more direct readout of tissue viability, has the potential to identify more patients likely to benefit from thrombolysis – irrespective of time from stroke onset – and patients within and beyond the 4·5 h thrombolysis treatment window who are unlikely to benefit and are at an increased risk of hemorrhage. Aims This study employs serial multimodal imaging and voxel-based analysis to develop optimal data processing for T2* oxygen challenge penumbra assessment. Tissue in the ischemic hemisphere is compartmentalized into penumbra, ischemic core, or normal using T2* oxygen challenge (single threshold) or T2* oxygen challenge plus cerebral blood flow (dual threshold) data. Penumbra defined by perfusion imaging/apparent diffusion coefficient mismatch (dual threshold) is included for comparison. Methods Permanent middle cerebral artery occlusion was induced in male Sprague-Dawley rats (n = 6) prior to serial multimodal imaging: T2* oxygen challenge, diffusion-weighted and perfusion imaging (cerebral blood flow using arterial spin labeling). Results Across the different methods evaluated, T2* oxygen challenge combined with perfusion imaging most closely predicted 24 h infarct volume. Penumbra volume declined from one to four-hours post-stroke: mean ± SD, 77 ± 44 to 49 ± 37 mm3 (single T2* oxygen challenge-based threshold); 55 ± 41 to 37 ± 12 mm3 (dual T2* oxygen challenge/cerebral blood flow); 84 ± 64 to 42 ± 18 mm3

  4. High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

    NASA Technical Reports Server (NTRS)

    Rahman, Atiar

    2006-01-01

    Background: Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). Methods and Results: 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P<0.001). Conclusions: Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

  5. High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P less than 0.00l). Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

  6. Methylene blue treatment delays progression of perfusion-diffusion mismatch to infarct in permanent ischemic stroke.

    PubMed

    Rodriguez, Pavel; Jiang, Zhao; Huang, Shiliang; Shen, Qiang; Duong, Timothy Q

    2014-11-07

    Stroke is a leading cause of morbidity and mortality in the world. Low-dose methylene blue (MB), which has been used safely to treat methemoglobinemia and cyanide poisoning in humans, has energy enhancing and antioxidant properties. We tested the hypothesis that methylene blue treatment delays progression of at-risk tissue (ca. perfusion-diffusion mismatch) to infarct in permanent middle cerebral artery occlusion in rats at two MB treatment doses. Serial MRI was used to evaluate MB treatment efficacy. The major findings were: (i) MB significantly prolonged the perfusion-diffusion mismatch, (ii) MB mildly increased the CBF in the hypoperfused tissue, (iii) MB did not change the final infarct volume in permanent ischemic stroke, and (iv) there were no dose-dependent effects on mismatch progression for the 1 and 3mg/kg doses studied. This neuroprotective effect is likely the result of sustained ATP production and increased CBF to tissue at risk. This work has the potential to readily lead to clinical stroke trials given MB's excellent safety profile.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Computed tomography perfusion and computed tomography angiography for prediction of clinical outcomes in ischemic stroke patients after thrombolysis

    PubMed Central

    Pan, Jia-wei; Yu, Xiang-rong; Zhou, Shu-yi; Wang, Jian-hong; Zhang, Jun; Geng, Dao-ying; Zhang, Tian-yu; Cheng, Xin; Ling, Yi-feng; Dong, Qiang

    2017-01-01

    Cerebral blood perfusion and cerebrovascular lesions are important factors that can affect the therapeutic efficacy of thrombolysis. At present, the majority of studies focus on assessing the accuracy of lesion location using imaging methods before treatment, with less attention to predictions of outcomes after thrombolysis. Thus, in the present study, we assessed the efficacy of combined computed tomography (CT) perfusion and CT angiography in predicting clinical outcomes after thrombolysis in ischemic stroke patients. The study included 52 patients who received both CT perfusion and CT angiography. Patients were grouped based on the following criteria to compare clinical outcomes: (1) thrombolytic and non-thrombolytic patients, (2) thrombolytic patients with CT angiography showing the presence or absence of a vascular stenosis, (3) thrombolytic patients with CT perfusion showing the presence or absence of hemodynamic mismatch, and (4) different CT angiography and CT perfusion results. Short-term outcome was assessed by the 24-hour National Institution of Health Stroke Scale score change. Long-term outcome was assessed by the 3-month modified Rankin Scale score. Of 52 ischemic stroke patients, 29 were treated with thrombolysis and exhibited improved short-term outcomes compared with those without thrombolysis treatment (23 patients). Patients with both vascular stenosis and blood flow mismatch (13 patients) exhibited the best short-term outcome, while there was no correlation of long-term outcome with CT angiography or CT perfusion findings. These data suggest that combined CT perfusion and CT angiography are useful for predicting short-term outcome, but not long-term outcome, after thrombolysis. PMID:28250755

  9. Clinical usefulness of combined radionuclide venography (RNV) and pulmonary perfusion scanning in thromboembolic disease

    SciTech Connect

    Dibos, P.E.; Park, B.J.; Luger, R.C.

    1985-05-01

    Radionuclide venography of the lower extremities and the pelvis (RNV) was performed in 1,089 patients with suspected deep venous thrombosis (INT) during the period February 1978 to December 1984. Sequential images of the calves, knees, thighs and pelvis were obtained immediately after injection of 2 mCi of Tc-99m MAA into a vein of the dorsum of each foot while tourniquets were applied above the ankles. Views of the same regions were obtained after releasing of the tourniquets. Six view pulmonary perfusion scanning (PPS) was performed routinely upon completion of RNV. Xe-133 pulmonary ventilation scans (PVS) were done just prior to RNV in patients suspected of having pulmonary embolism. Conventional radiographic venography (XRV) was obtained in 57 of the 1,089 patients; in most of these cases, XRV was carried out within 48 hours of RVV. Results of RNV and XRV were in agreement in 88% of the cases and conflicted in 12% of the 57 cases. DVT was diagnosed by RNV and XRV in 21 of the 57 patients who had both studies. RNV and XRV were normal in 29 of the 57 patients and conflicting results were obtained in 7 patients. There were 5 false-positive RNV (8.7%) and 2 false-negative RNV (3.5%) considering the XRV as the definitive study. Out of 260 patients scanned during 1984, 26 (10%) patients had RNV/PPS findings positive for DVT and pulmonary embolism (PE); in most of these cases (22) PE was clinically unsuspected. The authors conclude that RNV is a simple, safe, clinically useful technique in the evaluation of patients with suspected DVT. PPS should follow RNV routinely. The incidence of unsuspected PE in patients with DVT is high.

  10. Renal perfusion scintiscan

    MedlinePlus

    Renal perfusion scintigraphy; Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion ... supply the kidneys. This is a condition called renal artery stenosis. Significant renal artery stenosis may be ...

  11. PET imaging of cerebral perfusion and oxygen consumption in acute ischemic stroke: Relation to outcome

    SciTech Connect

    Marchal, G.; Serrati, C.; Rioux, P.; Petit-Taboue, M.C.; Viader, F.; Sayette, V. de la; Doze, F. le; Lonchon, P; Derlon, J.M.; Orgogozo, J.M.; Baron, J.C.

    1993-04-10

    The authors used positron emission tomography (PET) to assess the relation between combined imaging of cerebral blood flow and oxygen consumption 5-18 h after first middle cerebral artery (MCA) stroke and neurological outcome at 2 months. All 18 patients could be classified into three visually defined PET patterns of perfusion and oxygen consumption changes. Pattern 1 suggested extensive irreversible damage and was consistently associated with poor outcome. Pattern 2 suggested continuing ischemia and was associated with variable outcome. Pattern 3 with hyperperfusion and little or no metabolic alteration, was associated with excellent recovery, which suggests that early reperfusion is beneficial. This relation between PET and outcome was highly significant. The results suggest that within 5-18 h of stroke onset, PET is a good predictor of outcome in patterns 1 and 3, for which therapy seems limited. The absence of predictive value for pattern 2 suggests that it is due to a reversible ischemic state that is possibly amenable to therapy. These findings may have important implications for acute MCA stroke management and for patients' selection for therapeutic trials.

  12. Comparative value of maximal treadmill testing, exercise thallium myocardial perfusion scintigraphy and exercise radionuclide ventriculography for distinguishing high- and low-risk patients soon after acute myocardial infarction

    SciTech Connect

    Hung, J.; Goris, M.L.; Nash, E.; Kraemer, H.C.; DeBusk, R.F.; Berger, W.E.; Lew, H.

    1984-05-01

    The prognostic value of symptom-limited treadmill exercise electrocardiography, exercise thallium myocardial perfusion scintigraphy and rest and exercise radionuclide ventriculography was compared in 117 men, aged 54 +/- 9 years, tested 3 weeks after a clinically uncomplicated acute myocardial infarction (MI). During a mean follow-up period of 11.6 months, 8 men experienced ''hard'' medical events (cardiac death, nonfatal ventricular fibrillation or recurrent MI) and 14 were hospitalized for unstable angina pectoris, congestive heart failure or coronary bypass surgery (total of 22 combined events). By multivariate analysis (Cox proportional hazards model), peak treadmill work load and the change in left ventricular ejection fraction (EF) during exercise were significant (p less than 0.01) predictors of hard medical events; these 2 risk factors and recurrent ischemic chest pain in the coronary care unit were also significantly predictive (p less than 0.001) for combined events. A peak treadmill work load of 4 METs or less or a decrease in EF of 5% or more below the value at rest during submaximal effort distinguished 22 high-risk patients (20% of the study population) from 89 low-risk patients. The rate of hard medical events within 12 months was 23% (5 of 22 patients), vs 2% (2 of 89 patients) in the high- and low-risk patient subsets, respectively (p less than 0.001). Thus, in patients who underwent evaluation 3 weeks after a clinically uncomplicated MI, exercise radionuclide ventriculography contributed independent prognostic information to that provided by symptom-limited treadmill testing and was superior to exercise thallium scintigraphy for this purpose.

  13. Ischemic postconditioning influences electron transport chain protein turnover in Langendorff-perfused rat hearts

    PubMed Central

    Cao, Song; Liu, Yun; Wang, Haiying; Mao, Xiaowen; Chen, Jincong; Liu, Jiming; Xia, Zhengyuan; Zhang, Lin; Liu, Xingkui

    2016-01-01

    Ischemia postconditioning (IPo) is a promising strategy in reducing myocardial ischemia reperfusion (I/R) injury (MIRI), but its specific molecular mechanism is incompletely understood. Langendorff-perfused isolated rat hearts were subjected to global I/R and received IPo in the absence or presence of the mitochondrial ATP-sensitive potassium channel (mitoKATP) blocker 5-hydroxydecanoate (5-HD). Myocardial mitochondria were extracted and mitochondrial comparative proteomics was analyzed. IPo significantly reduces post-ischemic myocardial infarction and improved cardiac function in I/R rat hearts, while 5-HD basically cancelled IPo’s myocardial protective effect. Joint application of two-dimensional polyacrylamide gel electrophoresis (2DE) and MALDI-TOF MS identified eight differentially expressed proteins between groups. Expression of cardiac succinate dehydrogenase (ubiquinone) flavoprotein subunit (SDHA) increased more than two-fold after I/R, while IPo led to overexpression of dihydrolipoyl dehydrogenase (DLD), NADH dehydrogenase (ubiquinone) flavoprotein 1 and isoform CRA_b (NDUFV1). When the mitoKATP was blocked, MICOS complex subunit Mic60 (IMMT) and Stress-70 protein (Grp75) were over expressed, while DLDH, ATPase subunit A (ATPA) and rCG44606 were decreased. Seven of the differential proteins belong to electron transport chain (ETC) or metabolism regulating proteins, and five of them were induced by closing mitoKATP in I/R hearts. We thus conclude that IPo’s myocardial protective effect relies on energy homeostasis regulation. DLD, SDHA, NDUFV1, Grp75, ATPA and rCG44606 may contribute to IPo’s cardial protective effect. PMID:26925330

  14. Brain hemorrhage after endovascular reperfusion therapy of ischemic stroke: a threshold-finding whole-brain perfusion CT study.

    PubMed

    Renú, Arturo; Laredo, Carlos; Tudela, Raúl; Urra, Xabier; Lopez-Rueda, Antonio; Llull, Laura; Oleaga, Laura; Amaro, Sergio; Chamorro, Ángel

    2017-01-01

    Endovascular reperfusion therapy is increasingly used for acute ischemic stroke treatment. The occurrence of parenchymal hemorrhage is clinically relevant and increases with reperfusion therapies. Herein we aimed to examine the optimal perfusion CT-derived parameters and the impact of the duration of brain ischemia for the prediction of parenchymal hemorrhage after endovascular therapy. A cohort of 146 consecutive patients with anterior circulation occlusions and treated with endovascular reperfusion therapy was analyzed. Recanalization was assessed at the end of reperfusion treatment, and the rate of parenchymal hemorrhage at follow-up neuroimaging. In regression analyses, cerebral blood volume and cerebral blood flow performed better than Delay Time maps for the prediction of parenchymal hemorrhage. The most informative thresholds (receiver operating curves) for relative cerebral blood volume and relative cerebral blood flow were values lower than 2.5% of normal brain. In binary regression analyses, the volume of regions with reduced relative cerebral blood volume and/or relative cerebral blood flow was significantly associated with an increased risk of parenchymal hemorrhage, as well as delayed vessel recanalization. These results highlight the relevance of the severity and duration of ischemia as drivers of blood-brain barrier disruption in acute ischemic stroke and support the role of perfusion CT for the prediction of parenchymal hemorrhage.

  15. Pharmacological and other nonexercise alternatives to exercise testing to evaluate myocardial perfusion and left ventricular function with radionuclides

    SciTech Connect

    DePuey, E.G.; Rozanski, A. )

    1991-04-01

    Pharmacological vasodilatation with either dipyridamole or adenosine is a safe and accurate alternative to exercise testing to diagnose coronary artery disease with thallium 201 myocardial perfusion imaging. The technique also provides important prognostic information with regard to future cardiac events in patients undergoing diagnostic testing, in those evaluated preoperatively, and in those with recent myocardial infarctions. Multigated equilibrium and first-pass radionuclide ventriculography also are well suited to evaluate the effects of interventional procedures. Success has been achieved using this methodology in a variety of interventions including conventional exercise testing, pharmacological stress testing, atrial pacing, assessment of myocardial viability with nitroglycerin, mental stress testing, and ambulatory monitoring of left ventricular ejection fraction. 67 references.

  16. Reversibility of intrapulmonary arteriovenous shunts in liver cirrhosis documented by serial radionuclide perfusion lung scans

    SciTech Connect

    Chen, N.S.; Barnett, C.A.; Farrer, P.A.

    1984-05-01

    Using serial perfusion lung scans, the opening up and closure of right-to-left intrapulmonary arteriovenous shunts has been documented over a period of several weeks in a patient with chronic alcoholic liver disease. The presence of the shunts correlates well with the severity of hypoxemia and the presence of nodular mottling on chest radiographs. The time course of these changes with clinical status suggests lability and the functional nature of these shunts.

  17. Rest and exercise radionuclide angiography for diagnosis in chronic ischemic heart disease

    SciTech Connect

    Gibbons, R.J. )

    1991-09-01

    Rest and exercise radionuclide angiography is frequently employed for the diagnosis of chest pain syndromes. Its value and limitations in this regard have been well studied, but proper utilization of the technique requires an understanding of five critical concepts: (1) Radionuclide angiography is superior to treadmill exercise testing and probably equivalent to thallium scintigraphy, although the published series did not use current methods. (2) The true specificity of radionuclide angiography is about 80%, intermediate between the early optimistic estimates and the later pessimistic ones. (3) The peak exercise ejection fraction is the preferred test parameter for diagnosis, although exercise hemodynamics, symptoms, and electrocardiographic changes should also be considered. (4) Although radionuclide angiography is clearly helpful for noninvasive diagnosis, significant numbers of patients will continue to fall in an uncertain category. (5) The proper application of the technique requires recognition of its limitations and careful attention to technical details. When properly applied, this modality can make an important contribution to clinical decision making. 58 references.

  18. Computed tomography perfusion imaging may predict cognitive impairment in patients with first-time anterior circulation transient ischemic attack.

    PubMed

    Wang, Jun; Li, Yunming; Zheng, Bo; Wang, Jian; Wang, Zhiqiang; Duan, Dan; Li, Yuxia; Wang, Qingsong

    2016-04-01

    To determine whether computed tomography perfusion imaging (CTPI)-derived parameters are associated with vascular cognitive impairment (VCI) in patients with transient ischemic attack (TIA). Patients with first-time anterior circulation TIA (diagnosed within 24 h of onset) and normal cognition, treated between August 2009 and August 2014 at the Department of Neurology of Chengdu Military General Hospital, China, were analyzed retrospectively. Patients underwent whole-brain CTPI within 1 week of TIA to detect cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) and time to peak (TTP) in the ischemic region. Based on cognitive function assessment 4 weeks after TIA, using the Montreal cognitive assessment (MoCA) and mini mental state examination, the patients were divided into control and VCI groups. CTPI parameters and other clinical data were compared between groups, and Spearman's correlation analysis used to identify associations between cognitive scores and CTPI parameters in the VCI group. 50 patients (25 per group; aged 55-72 years) were included. Patient age, gender, smoking status, alcohol consumption, educational level, time from TIA onset to admission, time from TIA onset to CTPI, and prevalence of hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation and hyperhomocysteinemia did not differ between groups. Both groups showed TTP and MTT prolongation, CBF reduction, but no change in CBV in the ischemic region; these changes were significantly larger in the VCI group (P < 0.05). MTT correlated negatively with MoCA score (r = -0.51, P = 0.009). CTPI could facilitate early diagnosis of VCI in patients with anterior circulation TIA.

  19. Basal ganglia perfusion using dynamic color Doppler sonography in infants with hypoxic ischemic encephalopathy receiving therapeutic hypothermia: a pilot study

    PubMed Central

    Cassia, Guilherme; Morneault, Linda; Saint-Martin, Christine; Sant’Anna, Guilherme

    2016-01-01

    Background The objective of this study was to evaluate the cerebral perfusion of the basal ganglia in infants with hypoxic-ischemic encephalopathy (HIE) receiving hypothermia using dynamic color Doppler sonography (CDS) and investigate for any correlation between these measurements and survival. Methods Head ultrasound (HUS) was performed with a 9S4 MHz sector transducer in HIE infants submitted to hypothermia as part of their routine care. Measurements of cerebral perfusion intensity (CPI) with an 11LW4 MHz linear array transducer were performed to obtain static images and DICOM color Doppler videos of the blood flow in the basal ganglia area. Clinical and radiological data were evaluated retrospectively. The video images were analyzed by two radiologists using dedicated software, which allows automatic quantification of color Doppler data from a region of interest (ROI) by dynamically assessing color pixels and flow velocity during the heart cycle. CPI is expressed in cm/sec and is calculated by multiplying the mean velocity of all pixels divided by the area of the ROI. Three videos of 3 seconds each were obtained of the ROI, in the coronal plane, and used to calculate the CPI. Data are presented as mean ± SEM or median (quartiles). Results A total of 28 infants were included in this study: 16 male, 12 female. HUS was performed within the first 48 hours of therapeutic hypothermia treatment. CPI values were significantly higher in the seven non-survivors when compared to survivors (0.226±0.221 vs. 0.111±0.082 cm/sec; P=0.02). Conclusions Increased perfusion intensity of the basal ganglia area within the first 48 of therapeutic hypothermia treatment was associated with poor outcome in neonates with HIE. PMID:27942470

  20. Calpain inhibitors reduce retinal hypoxia in ischemic retinopathy by improving neovascular architecture and functional perfusion.

    PubMed

    Hoang, Mien V; Smith, Lois E H; Senger, Donald R

    2011-04-01

    In ischemic retinopathies, underlying hypoxia drives abnormal neovascularization that damages retina and causes blindness. The abnormal neovasculature is tortuous and leaky and fails to alleviate hypoxia, resulting in more pathological neovascularization and retinal damage. With an established model of ischemic retinopathy we found that calpain inhibitors, when administered in moderation, reduced architectural abnormalities, reduced vascular leakage, and most importantly reduced retinal hypoxia. Mechanistically, these calpain inhibitors improved stability and organization of the actin cytoskeleton in retinal endothelial cells undergoing capillary morphogenesis in vitro, and they similarly improved organization of actin cables within new blood vessels in vivo. Hypoxia induced calpain activity in retinal endothelial cells and severely disrupted the actin cytoskeleton, whereas calpain inhibitors preserved actin cables under hypoxic conditions. Collectively, these findings support the hypothesis that hyper-activation of calpains by hypoxia contributes to disruption of the retinal endothelial cell cytoskeleton, resulting in formation of neovessels that are defective both architecturally and functionally. Modest suppression of calpain activity with calpain inhibitors restores cytoskeletal architecture and promotes formation of a functional neovasculature, thereby reducing underlying hypoxia. In sharp contrast to "anti-angiogenesis" strategies that cannot restore normoxia and may aggravate hypoxia, the therapeutic strategy described here does not inhibit neovascularization. Instead, by improving the function of neovascularization to reduce underlying hypoxia, moderate calpain inhibition offers a method for alleviating retinal ischemia, thereby suggesting a new treatment paradigm based on improvement rather than inhibition of new blood vessel growth.

  1. Myocardial function and perfusion in the CREST syndrome variant of progressive systemic sclerosis. Exercise radionuclide evaluation and comparison with diffuse scleroderma

    SciTech Connect

    Follansbee, W.P.; Curtiss, E.I.; Medsger, T.A. Jr.; Owens, G.R.; Steen, V.D.; Rodnan, G.P.

    1984-09-01

    Myocardial function and perfusion were evaluated in 22 patients with progressive systemic sclerosis with the CREST syndrome using exercise and radionuclide techniques, pulmonary function testing, and chest roentgenography. The results were compared with a similar study of 26 patients with progressive systemic sclerosis with diffuse scleroderma. The prevalence of thallium perfusion abnormalities was similar in the groups with CREST syndrome and diffuse scleroderma, (64 percent versus 77 percent), but the defects were significantly smaller in the CREST syndrome (p less than 0.01). Reperfusion thallium defects in the absence of extramural coronary artery disease were seen in 38 percent of patients with diffuse scleroderma. This finding was not seen in any of the patients with the CREST syndrome. In diffuse scleroderma, abnormalities of both right and left ventricular function were related to larger thallium perfusion defects. In the CREST syndrome, abnormalities of left ventricular function were minor, were seen only during exercise, and were unrelated to thallium perfusion defects. Abnormal resting right ventricular function was seen in 36 percent of the patients with the CREST syndrome and was associated with an isolated decrease in diffusing capacity of carbon monoxide. It is concluded that the cardiac manifestations of the CREST syndrome are distinct from those found in diffuse scleroderma. Unlike diffuse scleroderma, abnormalities of left ventricular function in the CREST syndrome are minor and are unrelated to abnormalities of coronary perfusion. Right ventricular dysfunction in the CREST syndrome appears to be primarily related to pulmonary vascular disease.

  2. Is there more valuable information in PWI datasets for a voxel-wise acute ischemic stroke tissue outcome prediction than what is represented by typical perfusion maps?

    NASA Astrophysics Data System (ADS)

    Forkert, Nils Daniel; Siemonsen, Susanne; Dalski, Michael; Verleger, Tobias; Kemmling, Andre; Fiehler, Jens

    2014-03-01

    The acute ischemic stroke is a leading cause for death and disability in the industry nations. In case of a present acute ischemic stroke, the prediction of the future tissue outcome is of high interest for the clinicians as it can be used to support therapy decision making. Within this context, it has already been shown that the voxel-wise multi-parametric tissue outcome prediction leads to more promising results compared to single channel perfusion map thresholding. Most previously published multi-parametric predictions employ information from perfusion maps derived from perfusion-weighted MRI together with other image sequences such as diffusion-weighted MRI. However, it remains unclear if the typically calculated perfusion maps used for this purpose really include all valuable information from the PWI dataset for an optimal tissue outcome prediction. To investigate this problem in more detail, two different methods to predict tissue outcome using a k-nearest-neighbor approach were developed in this work and evaluated based on 18 datasets of acute stroke patients with known tissue outcome. The first method integrates apparent diffusion coefficient and perfusion parameter (Tmax, MTT, CBV, CBF) information for the voxel-wise prediction, while the second method employs also apparent diffusion coefficient information but the complete perfusion information in terms of the voxel-wise residue functions instead of the perfusion parameter maps for the voxel-wise prediction. Overall, the comparison of the results of the two prediction methods for the 18 patients using a leave-one-out cross validation revealed no considerable differences. Quantitatively, the parameter-based prediction of tissue outcome led to a mean Dice coefficient of 0.474, while the prediction using the residue functions led to a mean Dice coefficient of 0.461. Thus, it may be concluded from the results of this study that the perfusion parameter maps typically derived from PWI datasets include all

  3. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator.

    PubMed

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C

    2014-06-07

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  4. Simultaneous Tc-99m/I-123 Dual Radionuclide Myocardial Perfusion/Innervation Imaging Using Siemens IQ-SPECT with SMARTZOOM Collimator

    PubMed Central

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric. C.

    2014-01-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region compared to a typical parallel-hole low-energy high-resolution collimator but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulation and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter modeling

  5. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator

    NASA Astrophysics Data System (ADS)

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C.

    2014-06-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  6. Effectiveness of skin perfusion pressure monitoring during surgery for an ischemic steal syndrome associated refractory ulcer.

    PubMed

    Okubo, Kentaro; Sato, Takashi; Matsubara, Chieko; Tsuboi, Masato; Ishii, Yasuo; Tojimbara, Tamotsu

    2015-01-01

    We describe an 80-year-old man with end-stage renal disease due to type 2 diabetes who had been maintained on hemodialysis for 9 years. He developed refractory ulcers from an abraded wound in the right hand of his access arm. The arteriovenous fistula (AVF) was located between the right brachial artery and the median antecubital vein draining into the cephalic vein and the deep veins close to the elbow. The blood flow of the right brachial artery measured by using Doppler ultrasonography was 920 ml/min. On the contrary, the radial and ulnar arteries were poorly palpable near the wrist, and ultrasonography could not be performed accurately because of a high degree of calcification. The skin perfusion pressure (SPP) of the first finger on the affected side decreased to 22 mmHg. However, the SPP improved to approximately 40 mmHg upon blocking an inflow into the deep vein. According to SPP data, only a communicating branch of the deep vein was ligated, and the AVF itself was preserved. One month after surgery, the skin ulcer healed, and maintenance hemodialysis was performed by using the preserved cephalic vein for blood access.In conclusion, we successfully treated a refractory wound associated with steal syndrome, without terminating the AVF. SPP-guided surgery may be safe and effective to adjust the blood flow in patients with AVF having steal syndrome.

  7. Whole-brain CT perfusion combined with CT angiography for ischemic complications following microsurgical clipping and endovascular coiling of ruptured intracranial aneurysms.

    PubMed

    Cheng, Xiao Qing; Chen, Qian; Zhou, Chang Sheng; Li, Jian Rui; Zhang, Zong Jun; Zhang, Long Jiang; Huang, Wei; Lu, Guang Ming

    2016-04-01

    Ischemic complications associated with microsurgical clipping and endovascular coiling affects the outcome of patients with intracranial aneurysms. We prospectively evaluated 58 intracranial aneurysm patients who had neurological deterioration or presented with poor grade (Hunt-Hess grades III and IV), aneurysm size >13 mm and multiple aneurysms after clipping or coiling. Thirty patients had ischemic complications (52%) as demonstrated by whole-brain CT perfusion (WB-CTP) combined with CT angiography (CTA). Half of these 30 patients had treatment-associated reduction in the diameter of the parent vessels (n=6), ligation of the parent vessels or perforating arteries (n=2), and unexplained or indistinguishable vascular injury (n=7); seven of these 15 (73%) patients suffered infarction. The remaining 15 patients had disease-associated cerebral ischemia caused by generalized vasospasm (n=6) and focal vessel vasospasm (n=9); six of these 15 (40%) patients developed infarction. Three hemodynamic patterns of ischemic complications were found on WB-CTP, of which increased time to peak, time to delay and mean transit time associated with decreased cerebral blood flow and cerebral blood volume were the main predictors of irreversible ischemic lesions. In conclusion, WB-CTP combined with CTA can accurately determine the cause of neurological deterioration and classify ischemic complications. This combined approach may be helpful in assessing hemodynamic patterns and monitoring operative outcomes.

  8. Spatiotemporal Dynamic Simulation of Acute Perfusion/Diffusion Ischemic Stroke Lesions Evolution: A Pilot Study Derived from Longitudinal MR Patient Data

    PubMed Central

    Rekik, Islem; Allassonnière, Stéphanie; Durrleman, Stanley; Carpenter, Trevor; Wardlaw, Joanna

    2013-01-01

    The spatiotemporal evolution of stroke lesions, from acute injury to final tissue damage, is complex. Diffusion-weighted (DWI) and perfusion-weighted (PWI) imaging is commonly used to detect early ischemic changes and attempts to distinguish between permanently damaged and salvageable tissues. To date, 2D and 3D measures of diffusion/perfusion regions at individual timepoints have been widely used but may underestimate the true lesion spatio-temporal dynamics. Currently there is no spatio-temporal 4D dynamic model that simulates the continuous evolution of ischemic stroke from MR images. We determined whether a 4D current-based diffeomorphic model, developed in the field of statistical modeling for measuring the variability of anatomical surfaces, could estimate patient-specific spatio-temporal continuous evolution for MR PWI (measured as mean transit time, (MTT)) and DWI lesions. In our representative pilot sample, the model fitted the data well. Our dynamic analysis of lesion evolution showed different patterns; for example, some DWI/PWI dynamic changes corresponded with DWI lesion expansion into PWI lesions, but other patterns were much more complex and diverse. There was wide variation in the time when the final tissue damage was reached after stroke for DWI and MTT. PMID:23853669

  9. Using longitudinal metamorphosis to examine ischemic stroke lesion dynamics on perfusion-weighted images and in relation to final outcome on T2-w images

    PubMed Central

    Rekik, Islem; Allassonnière, Stéphanie; Carpenter, Trevor K.; Wardlaw, Joanna M.

    2014-01-01

    We extend the image-to-image metamorphosis into constrained longitudinal metamorphosis. We apply it to estimate an evolution scenario, in patients with acute ischemic stroke, of both scattered and solitary ischemic lesions visible on serial MR perfusion weighted imaging from acute to subacute stages. We then estimate a patient-specific residual map that enables us to capture the most relevant shape and intensity changes, continuously, as the lesion evolves from acute through subacute to chronic timepoints until merging into the final image. We detect areas with high residuals (i.e., high dynamics) and identify areas that became part of the final T2-w lesion obtained at ≥ 1 month after stroke. This allows the investigation of the dynamic influence of perfusion values on the final lesion outcome as seen on T2-w imaging. The model provides detailed insights into stroke lesion dynamic evolution in space and time that will help identify factors that determine final outcome and identify targets for interventions to improve outcome. PMID:25161899

  10. Near-Infrared Spectroscopy versus Magnetic Resonance Imaging To Study Brain Perfusion in Newborns with Hypoxic-Ischemic Encephalopathy Treated with Hypothermia

    PubMed Central

    Wintermark, P.; Hansen, A.; Warfield, SK.; Dukhovny, D.; Soul, JS.

    2014-01-01

    Background The measurement of brain perfusion may provide valuable information for assessment and treatment of newborns with hypoxic-ischemic encephalopathy (HIE). While arterial spin labeled perfusion (ASL) magnetic resonance imaging (MRI) provides noninvasive and direct measurements of regional cerebral blood flow (CBF) values, it is logistically challenging to obtain. Near-infrared spectroscopy (NIRS) might be an alternative, as it permits noninvasive and continuous monitoring of cerebral hemodynamics and oxygenation at the bedside. Objective The purpose of this study is to determine the correlation between measurements of brain perfusion by NIRS and by MRI in term newborns with HIE treated with hypothermia. Design/Methods In this prospective cohort study, ASL-MRI and NIRS performed during hypothermia were used to assess brain perfusion in these newborns. Regional cerebral blood flow values (CBF), measured from 1–2 MRI scans for each patient, were compared to mixed venous saturation values (SctO2) recorded by NIRS just before and after each MRI. Analysis included groupings into moderate versus severe HIE based on their initial background pattern of amplitude-integrated electroencephalogram. Results Twelve concomitant recordings were obtained of seven neonates. Strong correlation was found between SctO2 and CBF in asphyxiated newborns with severe HIE (r = 0.88; p value = 0.0085). Moreover, newborns with severe HIE had lower CBF (likely lower oxygen supply) and extracted less oxygen (likely lower oxygen demand or utilization) when comparing SctO2 and CBF to those with moderate HIE. Conclusions NIRS is an effective bedside tool to monitor and understand brain perfusion changes in term asphyxiated newborns, which in conjunction with precise measurements of CBF obtained by MRI at particular times, may help tailor neuroprotective strategies in term newborns with HIE. PMID:23631990

  11. Successful outcome after endovascular thrombolysis for acute ischemic stroke with basis on perfusion-diffusion mismatch after 24 h of symptoms onset

    PubMed Central

    Mattei, Tobias A.; Rehman, Azeem A.; Goulart, Carlos R.; Sória, Marília G.; Rizelio, Vanessa; Meneses, Murilo S.

    2016-01-01

    Background: Although intravenous thrombolysis is the Food and Drug Administration-approved treatment for acute ischemic stroke (AIS) within 3 h, combined intravenous and intra-arterial thrombolysis with endovascular techniques may be able to extend this traditional time window. Case Description: We present the clinical evolution of a 45-year-old male presenting with acute left hemiparesis. Magnetic resonance imaging revealed a small diffusion restriction at the right basal ganglia with perfusion compromise in the entire right middle cerebral artery (MCA) territory. Angiography revealed a complete occlusion of MCA at its M1 segment. The patient underwent endovascular mechanical thrombectomy with additional intra-arterial thrombolysis more than 24 hours after the onset of the initial symptoms and experienced complete vessel recanalization. At 1 year, the patient had global independence with minor residual motor impairment in the left arm. Conclusions: We report the case of a successful thrombolytic therapy following AIS performed more than 24 h after the initial symptoms based on the presence of a perfusion-diffusion mismatch. This report is expected to stimulate the development of future prospective studies with special focus on the role of perfusion-diffusion mismatch in patient selection for treatment of AIS, especially in those presenting outside the traditional time window. PMID:27313971

  12. SU-C-201-04: Quantification of Perfusion Heterogeneity Based On Texture Analysis for Fully Automatic Detection of Ischemic Deficits From Myocardial Perfusion Imaging

    SciTech Connect

    Fang, Y; Huang, H; Su, T

    2015-06-15

    Purpose: Texture-based quantification of image heterogeneity has been a popular topic for imaging studies in recent years. As previous studies mainly focus on oncological applications, we report our recent efforts of applying such techniques on cardiac perfusion imaging. A fully automated procedure has been developed to perform texture analysis for measuring the image heterogeneity. Clinical data were used to evaluate the preliminary performance of such methods. Methods: Myocardial perfusion images of Thallium-201 scans were collected from 293 patients with suspected coronary artery disease. Each subject underwent a Tl-201 scan and a percutaneous coronary intervention (PCI) within three months. The PCI Result was used as the gold standard of coronary ischemia of more than 70% stenosis. Each Tl-201 scan was spatially normalized to an image template for fully automatic segmentation of the LV. The segmented voxel intensities were then carried into the texture analysis with our open-source software Chang Gung Image Texture Analysis toolbox (CGITA). To evaluate the clinical performance of the image heterogeneity for detecting the coronary stenosis, receiver operating characteristic (ROC) analysis was used to compute the overall accuracy, sensitivity and specificity as well as the area under curve (AUC). Those indices were compared to those obtained from the commercially available semi-automatic software QPS. Results: With the fully automatic procedure to quantify heterogeneity from Tl-201 scans, we were able to achieve a good discrimination with good accuracy (74%), sensitivity (73%), specificity (77%) and AUC of 0.82. Such performance is similar to those obtained from the semi-automatic QPS software that gives a sensitivity of 71% and specificity of 77%. Conclusion: Based on fully automatic procedures of data processing, our preliminary data indicate that the image heterogeneity of myocardial perfusion imaging can provide useful information for automatic determination

  13. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study.

    PubMed

    Lázaro, Alberto; Humanes, Blanca; Jado, Juan Carlos; Mojena, Marina; González-Nicolás, María Ángeles; Del Cañizo, Juan Francisco; Tejedor, Alberto; Lledó-García, Enrique

    2016-01-01

    Warm ischemia (WI) produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP) seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis), and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only.

  14. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study

    PubMed Central

    Humanes, Blanca; Jado, Juan Carlos; Mojena, Marina; González-Nicolás, María Ángeles; del Cañizo, Juan Francisco; Lledó-García, Enrique

    2016-01-01

    Warm ischemia (WI) produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP) seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis), and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only. PMID:27556029

  15. Reconditioning by end-ischemic hypothermic in-house machine perfusion: A promising strategy to improve outcome in expanded criteria donors kidney transplantation.

    PubMed

    Gallinat, Anja; Amrillaeva, Vera; Hoyer, Dieter P; Kocabayoglu, Peri; Benko, Tamas; Treckmann, Jürgen W; van Meel, Marieke; Samuel, Undine; Minor, Thomas; Paul, Andreas

    2017-03-01

    This clinical study evaluates end-ischemic hypothermic machine perfusion (eHMP) in expanded criteria donors (ECD) kidneys. eHMP was initiated upon arrival of the kidney in our center and continued until transplantation. Between 11/2011 and 8/2014 eHMP was performed in 66 ECD kidneys for 369 (98-912) minutes after 863 (364-1567) minutes of cold storage (CS). In 49 of 66 cases, the contralateral kidney from the same donor was preserved by static CS only and accepted by another Eurotransplant (ET) center. Five (10.2%) of these kidneys were ultimately judged as "not transplantable" by the accepting center and discarded. After exclusion of early unrelated graft losses, 43 kidney pairs from the same donor were eligible for direct comparison of eHMP vs CS only: primary non-function and delayed graft function (DGF) were 0% vs 9.3% (P=.04) and 11.6% vs 20.9% (P=.24). There was no statistically significant difference in 1-year graft survival (eHMP vs CS only: 97.7% vs 88.4%, P=.089). In a multivariate analysis, eHMP was an independent factor for prevention of DGF (OR: 0.28, P=.041). Development of DGF was the strongest risk factor for 1-year graft failure (Renal resistance: 38.2, P<.001). In summary, eHMP is a promising reconditioning technique to improve the quality and acceptance rate of suboptimal grafts.

  16. Effect of Transendocardial Delivery of Autologous Bone Marrow Mononuclear Cells on Functional Capacity, Left Ventricular Function, and Perfusion in Chronic Ischemic Heart Failure: The FOCUS-CCTRN Trial

    PubMed Central

    Perin, Emerson C.; Willerson, James T.; Pepine, Carl J.; Henry, Timothy D.; Ellis, Stephen G.; Zhao, David X.M.; Silva, Guilherme V.; Lai, Dejian; Thomas, James D.; Kronenberg, Marvin W.; Martin, A. Daniel; Anderson, R. David; Traverse, Jay H.; Penn, Marc S.; Anwaruddin, Saif; Hatzopoulos, Antonis K.; Gee, Adrian P.; Taylor, Doris A.; Cogle, Christopher R.; Smith, Deirdre; Westbrook, Lynette; Chen, James; Handberg, Eileen; Olson, Rachel E.; Geither, Carrie; Bowman, Sherry; Francescon, Judy; Baraniuk, Sarah; Piller, Linda B.; Simpson, Lara M.; Loghin, Catalin; Aguilar, David; Richman, Sara; Zierold, Claudia; Bettencourt, Judy; Sayre, Shelly L.; Vojvodic, Rachel W.; Skarlatos, Sonia I.; Gordon, David J.; Ebert, Ray F.; Kwak, Minjung; Moyé, Lemuel A.; Simari, Robert D.

    2013-01-01

    Context Previous studies utilizing autologous bone marrow mononuclear cells (BMCs) in patients with ischemic cardiomyopathy have demonstrated safety and suggested efficacy. The FOCUS protocol was designed to assess efficacy of a larger cell dose in an adequately well-powered phase II study. Objective To determine if administration of BMCs through transendocardial injections improves myocardial perfusion, reduces left ventricular (LV) end systolic volume, or enhances maximal oxygen consumption in patients with coronary artery disease (CAD), LV dysfunction, and limiting heart failure and/or angina. Design, Setting, and Patients This is a 100 million cell, first-in-man randomized, double-blind, placebo-controlled trial was performed by the National Heart, Lung, and Blood Institute-sponsored Cardiovascular Cell Therapy Research Network (CCTRN) in symptomatic patients (NYHA II-III and/or CCS II-IV) receiving maximal medical therapy, with a left ventricular ejection fraction (LVEF)≤45%, perfusion defect by single-photon emission tomography (SPECT), and CAD not amenable to revascularization. Intervention All patients underwent bone marrow aspiration, isolation of BMCs using a standardized automated system performed locally, and transendocardial injection of 100 million BMCs or placebo (2:1 BMC: placebo). Main Outcome Measures Three co-primary endpoints assessed at 6 months were changes in (a) LV end systolic volume (LVESV) by echocardiography, (b) maximal oxygen consumption (MVO2), and (c) reversibility on SPECT. Secondary measures included other SPECT measures, magnetic resonance imaging (MRI), echocardiography, clinical improvement, and major adverse cardiac events (MACE). Phenotypic and functional analyses of the cell product were performed by the CCTRN Biorepository lab. Results Of 153 consented patients, a total of 92 (82 men; average age, 63 years) were randomized (n= 61 BMC, 31 placebo) at 5 sites between April 29, 2009 and April 18, 2011. Changes in LVESV index

  17. Ischemic Colitis Revealing Polyarteritis Nodosa

    PubMed Central

    Hamzaoui, Amira; Litaiem, Noureddine; Smiti Khanfir, M.; Ayadi, Sofiene; Nfoussi, Haifa; Houman, M. H.

    2013-01-01

    Ischemic colitis is one of the most common intestinal ischemic injuries. It results from impaired perfusion of blood to the bowel and is rarely caused by vasculitis. We report a case of ischemic colitis revealing polyarteritis nodosa (PAN) in a 55-year-old man. Histological examination of the resected colon led to the diagnosis of PAN. PMID:24382967

  18. Myocardial perfusion imaging for detection of silent myocardial ischemia

    SciTech Connect

    Beller, G.A.

    1988-04-21

    Despite the widespread use of the exercise stress test in diagnosing asymptomatic myocardial ischemia, exercise radionuclide imaging remains useful for detecting silent ischemia in numerous patient populations, including those who are totally asymptomatic, those who have chronic stable angina, those who have recovered from an episode of unstable angina or an uncomplicated myocardial infarction, and those who have undergone angioplasty or received thrombolytic therapy. Studies show that thallium scintigraphy is more sensitive than exercise electrocardiography in detecting ischemia, i.e., in part, because perfusion defects occur more frequently than ST depression and before angina in the ischemic cascade. Thallium-201 scintigraphy can be performed to differentiate a true- from a false-positive exercise electrocardiographic test in patients with exercise-induced ST depression and no angina. The development of technetium-labeled isonitriles may improve the accuracy of myocardial perfusion imaging. 11 references.

  19. In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core?

    PubMed Central

    Copen, William A.; Morais, Livia T.; Wu, Ona; Schwamm, Lee H.; Schaefer, Pamela W.; González, R. Gilberto; Yoo, Albert J.

    2015-01-01

    Background and Purpose In the treatment of patients with suspected acute ischemic stroke, increasing evidence suggests the importance of measuring the volume of the irreversibly injured “ischemic core.” The gold standard method for doing this in the clinical setting is diffusion-weighted magnetic resonance imaging (DWI), but many authors suggest that maps of regional cerebral blood volume (CBV) derived from computed tomography perfusion imaging (CTP) can substitute for DWI. We sought to determine whether DWI and CTP-derived CBV maps are equivalent in measuring core volume. Methods 58 patients with suspected stroke underwent CTP and DWI within 6 hours of symptom onset. We measured low-CBV lesion volumes using three methods: “objective absolute,” i.e. the volume of tissue with CBV below each of six published absolute thresholds (0.9–2.5 mL/100 g), “objective relative,” whose six thresholds (51%-60%) were fractions of mean contralateral CBV, and “subjective,” in which two radiologists (R1, R2) outlined lesions subjectively. We assessed the sensitivity and specificity of each method, threshold, and radiologist in detecting infarction, and the degree to which each over- or underestimated the DWI core volume. Additionally, in the subset of 32 patients for whom follow-up CT or MRI was available, we measured the proportion of CBV- or DWI-defined core lesions that exceeded the follow-up infarct volume, and the maximum amount by which this occurred. Results DWI was positive in 72% (42/58) of patients. CBV maps’ sensitivity/specificity in identifying DWI-positive patients were 100%/0% for both objective methods with all thresholds, 43%/94% for R1, and 83%/44% for R2. Mean core overestimation was 156–699 mL for objective absolute thresholds, and 127–200 mL for objective relative thresholds. For R1 and R2, respectively, mean±SD subjective overestimation were -11±26 mL and -11±23 mL, but subjective volumes differed from DWI volumes by up to 117 and 124

  20. Quantitative analysis of the impact of total ischemic time on myocardial perfusion and clinical outcome in patients with ST-elevation myocardial infarction.

    PubMed

    Fokkema, Marieke L; Wieringa, Wouter G; van der Horst, Iwan C; Boersma, Eric; Zijlstra, Felix; de Smet, Bart J

    2011-12-01

    Early reperfusion of the infarct-related coronary artery is an important issue in improvement of outcomes after ST-segment elevation myocardial infarction (STEMI). In this study, the clinical significance of total ischemic time on myocardial reperfusion and clinical outcomes was evaluated in patients with STEMI treated with primary percutaneous coronary intervention and thrombus aspiration and additional triple-antiplatelet therapy. Total ischemic time was defined as time from symptom onset to first intracoronary therapy (first balloon inflation or thrombus aspiration). All patients with STEMI treated with primary percutaneous coronary intervention with total ischemic times ≥30 minutes and <24 hours from 2005 to 2008 were selected. Ischemic times were available in 1,383 patients, of whom 18.4% presented with total ischemic times ≤2 hours, 31.2% >2 to 3 hours, 26.8% >3 to 5 hours, and 23.5% >5 hours. Increased ischemic time was associated with age, female gender, hypertension, and diabetes. Patients with total ischemic times <5 hours more often had myocardial blush grade 3 (40% to 45% vs 22%, p <0.001) and complete ST-segment resolution (55% to 60% vs 42%, p = 0.002) than their counterparts with total ischemic times >5 hours. In addition, patients with total ischemic times ≤5 hours had lower 30-day mortality (1.5% vs 4.0%, p = 0.032) than patients with total ischemic times >5 hours. In conclusion, in this contemporary cohort of patients with STEMI treated with primary percutaneous coronary intervention, triple-antiplatelet therapy, and thrombus aspiration, short ischemic time was associated with better myocardial reperfusion and decreased mortality. After a 5-hour period in which outcomes remain relatively stable, myocardial reperfusion becomes suboptimal and mortality increases.

  1. Radionuclide surveillance of the allografted pancreas

    SciTech Connect

    George, E.A.; Salimi, Z.; Carney, K.; Castaneda, M.; Garvin, P.J.

    1988-04-01

    To determine the value of scintigraphy to detect posttransplantation complications of the allografted pancreas, we retrospectively reviewed 209 scintigrams obtained with /sup 99m/Tc-sulfur colloid (/sup 99m/Tc-SC) and /sup 99m/Tc-glucoheptonate (/sup 99m/Tc-GH). The scintigraphic studies were performed in 37 recipients of simultaneous renal and pancreatic allografts harvested from the same donor. /sup 99m/Tc-SC was used as an indicator of thrombotic vasculitis; pancreatic perfusion and blood-pool parameters were monitored with /sup 99m/Tc-GH. In 11 of the 37 recipients, scintigraphic abnormalities suggested posttransplantation infarction. Recurrent episodes of acute rejection of the pancreatic allograft, which always coincided with acute rejection of the renal allograft, were monitored in 24 recipients. Rejection-induced ischemic pancreatitis was suggested in 12 of the 24 recipients and persisted in 10 recipients for several weeks after improvement of renal allograft rejection. Pancreatic atrophy was suggested scintigraphically in 16 of the 24 recipients with recurrent episodes of rejection. Spontaneous pancreatic-duct obstruction and obstructive pancreatitis were associated with a scintigraphic pattern similar to that of rejection-induced ischemic pancreatitis. We concluded that the specific radionuclides used in this series are useful for the surveillance and assessment of posttransplantation pancreatic infarction, acute rejection, pancreatitis, and atrophy

  2. Radionuclide Therapy

    NASA Astrophysics Data System (ADS)

    Zalutsky, M. R.

    Radionuclide therapy utilizes unsealed sources of radionuclides as a treatment for cancer or other pathological conditions such as rheumatoid arthritis. Radionuclides that decay by the emission of β and α particles, as well as those that emit Auger electrons, have been used for this purpose. In this chapter, radiochemical aspects of radionuclide therapy, including criteria for radionuclide selection, radionuclide production, radiolabeling chemistry, and radiation dosimetry are discussed.

  3. Video instrumentation for radionuclide angiocardiography.

    NASA Technical Reports Server (NTRS)

    Kriss, J. P.

    1973-01-01

    Two types of videoscintiscopes for performing radioisotopic angiocardiography with a scintillation camera are described, and use of these instruments in performing clinical studies is illustrated. Radionuclide angiocardiography is a simple, quick and accurate procedure recommended as a screening test for patients with a variety of congenital and acquired cardiovascular lesions. When performed in conjunction with coronary arterial catheterization, dynamic radionuclide angiography may provide useful information about regional myocardial perfusion. Quantitative capabilities greatly enhance the potential of this diagnostic tool.

  4. Pharmacologic effects of a nitrate coronary vasodilator on cardiac perfusion and function, measured semiquantitatively

    SciTech Connect

    Winsor, D.W.; Winsor, T.; Krohn, B.G.; Bernett, J.R.

    1982-09-01

    Peritrate (pentaerythritol tetranitrate), a nitrate coronary vasodilator, was capable of significantly increasing perfusion and function in ischemic heart muscle. The A2 image-processing computer with software developed by Burow was used to evaluate regional perfusion and segmental wall motion in six patients with ischemic areas in the myocardium. These image-processing techniques were satisfactory for evaluation of ischemic heart muscle.

  5. The value of resting-state functional MRI in subacute ischemic stroke: comparison with dynamic susceptibility contrast-enhanced perfusion MRI.

    PubMed

    Ni, Ling; Li, Jingwei; Li, Weiping; Zhou, Fei; Wang, Fangfang; Schwarz, Christopher G; Liu, Renyuan; Zhao, Hui; Wu, Wenbo; Zhang, Xin; Li, Ming; Yu, Haiping; Zhu, Bin; Villringer, Arno; Zang, Yufeng; Zhang, Bing; Lv, Yating; Xu, Yun

    2017-01-31

    To evaluate the potential clinical value of the time-shift analysis (TSA) approach for resting-state fMRI (rs-fMRI) blood oxygenation level-dependent (BOLD) data in detecting hypoperfusion of subacute stroke patients through comparison with dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI). Forty patients with subacute stroke (3-14 days after neurological symptom onset) underwent MRI examination. Cohort A: 31 patients had MRA, DSC-PWI and BOLD data. Cohort B: 9 patients had BOLD and MRA data. The time delay between the BOLD time course in each voxel and the mean signal of global and contralateral hemisphere was calculated using TSA. Time to peak (TTP) was employed to detect hypoperfusion. Among cohort A, 14 patients who had intracranial large-vessel occlusion/stenosis with sparse collaterals showed hypoperfusion by both of the two approaches, one with abundant collaterals showed neither TTP nor TSA time delay. The remaining 16 patients without obvious MRA lesions showed neither TTP nor TSA time delay. Among cohort B, eight patients showed time delay areas. The TSA approach was a promising alternative to DSC-PWI for detecting hypoperfusion in subacute stroke patients who had obvious MRA lesions with sparse collaterals, those with abundant collaterals would keep intact local perfusion.

  6. The value of resting-state functional MRI in subacute ischemic stroke: comparison with dynamic susceptibility contrast-enhanced perfusion MRI

    PubMed Central

    Ni, Ling; Li, Jingwei; Li, Weiping; Zhou, Fei; Wang, Fangfang; Schwarz, Christopher G.; Liu, Renyuan; Zhao, Hui; Wu, Wenbo; Zhang, Xin; Li, Ming; Yu, Haiping; Zhu, Bin; Villringer, Arno; Zang, Yufeng; Zhang, Bing; Lv, Yating; Xu, Yun

    2017-01-01

    To evaluate the potential clinical value of the time-shift analysis (TSA) approach for resting-state fMRI (rs-fMRI) blood oxygenation level-dependent (BOLD) data in detecting hypoperfusion of subacute stroke patients through comparison with dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI). Forty patients with subacute stroke (3–14 days after neurological symptom onset) underwent MRI examination. Cohort A: 31 patients had MRA, DSC-PWI and BOLD data. Cohort B: 9 patients had BOLD and MRA data. The time delay between the BOLD time course in each voxel and the mean signal of global and contralateral hemisphere was calculated using TSA. Time to peak (TTP) was employed to detect hypoperfusion. Among cohort A, 14 patients who had intracranial large-vessel occlusion/stenosis with sparse collaterals showed hypoperfusion by both of the two approaches, one with abundant collaterals showed neither TTP nor TSA time delay. The remaining 16 patients without obvious MRA lesions showed neither TTP nor TSA time delay. Among cohort B, eight patients showed time delay areas. The TSA approach was a promising alternative to DSC-PWI for detecting hypoperfusion in subacute stroke patients who had obvious MRA lesions with sparse collaterals, those with abundant collaterals would keep intact local perfusion. PMID:28139701

  7. Radionuclide trap

    DOEpatents

    McGuire, Joseph C.

    1978-01-01

    The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.

  8. Effects of transmyocardial laser revascularization using a prototype pulsed CO2 laser on contractility and perfusion of chronically ischemic myocardium in a porcine model

    NASA Astrophysics Data System (ADS)

    Wadia, Yasmin; Khaki, Ali; Kajitani, Michio; Mori, Yoshiki; Irvine, Timothy; Sahn, David; Yessik, Michael J.; Bahlman, Deborah T.; Furnary, Anthony; Gregory, Kenton W.

    1999-06-01

    The purpose of this study was to test a new prototype pulsed CO2 laser to be used for transmyocardial laser revascularization (TMR). We want to determine whether it can reduce thermal damage and mitigate induced ischemia with improvement in contractile reserve of the heart as evidenced by contrast echocardiography at rest and under dobutamine stress. TMR is an emerging surgical strategy for treatment of myocardial ischemia not amenable to conventional percutaneous or surgical revascularization. Eleven pigs underwent amaroid occulder placement on the origin of the circumflex coronary artery. Six weeks laser occlusion of the circumflex coronary artery was documented. TMR was then done on ten pigs using a prototype pulsed CO2 laser that delivered 8-12 joules energy in 1.5ms with a spot sizes of 1mm. Six weeks after TMR the pigs were restudied and sacrificed. The animals developed significant ischemia after six weeks of ameroid occlusion, at rest (p=0.01) and at peak stress (p=0.004). Wall motion for the ischemic segments improved significantly six weeks after TMR at peak stress (p=0.02). TMR results in an improvement in wall motion in our model of chromic ischemia and improves WMSI significantly during induced stress than at rest.

  9. Radionuclide Generators

    NASA Astrophysics Data System (ADS)

    Rösch, F.; Knapp, F. F. (Russ)

    Radionuclide generator systems continue to play a key role in providing both diagnostic and therapeutic radionuclides for various applications in nuclear medicine, oncology, and interventional cardiology. Although many parent/daughter pairs have been evaluated as radionuclide generator systems, there are a relatively small number of generators, which are currently in routine clinical and research use. Essentially every conceivable approach has been used for parent/separation strategies, including sublimation, thermochromatographic separation, solvent extraction, and adsorptive column chromatography. The most widely used radionuclide generator for clinical applications is the 99Mo/99mTc generator system, but recent years have seen an enormous increase in the use of generators to provide therapeutic radionuclides, which has paralleled the development of complementary technologies for targeting agents for therapy and in the general increased interest in the use of unsealed therapeutic radioactive sources. More recently, use of the 68Ge/68Ga generator is showing great potential as a source of positron-emitting 68Ga for positron emission tomography (PET)/CT imaging. Key advantages for the use of radionuclide generators include reasonable costs, the convenience of obtaining the desired daughter radionuclide on demand, and availability of the daughter radionuclide in high specific activity, no-carrier added form.

  10. Ischemic Stroke

    MedlinePlus

    A stroke is a medical emergency. There are two types - ischemic and hemorrhagic. Ischemic stroke is the most common type. It is usually ... are at risk for having a more serious stroke. Symptoms of stroke are Sudden numbness or weakness ...

  11. Radionuclide cisternogram

    MedlinePlus

    ... please enable JavaScript. A radionuclide cisternogram is a nuclear scan test. It is used to diagnose problems ... damage. The amount of radiation used during the nuclear scan is very small. Almost all of the ...

  12. Arterial Spin Label Imaging of Acute Ischemic Stroke and Transient Ischemic Attack

    PubMed Central

    Zaharchuk, Greg

    2011-01-01

    Since acute ischemic stroke and transient ischemic attack (TIA) are fundamentally disruptions of brain hemodynamics, neuroimaging of brain perfusion might be expected to be of clinical utility. Recently, a noncontrast method of measuring CBF using arterial spin labeling (ASL) has become feasible in the clinical setting. It has advantages when compared to dynamic susceptibility contrast (DSC) bolus contrast perfusion-weighted imaging (PWI) that include lack of exposure to gadolinium-based contrast materials, improved quantitation, and decreased sensitivity to susceptibility artifacts and motion. Drawbacks of ASL include reduced signal-to-noise (SNR) and high sensitivity to arterial transit delays. While deleterious for quantitative perfusion measurements, the sensitivity of ASL to late arriving blood can be beneficial to visualize collateral flow. This chapter will discuss ASL imaging findings in patients presenting with acute ischemic stroke and TIA, focusing on typical appearances, common artifacts, and comparisons with bolus contrast PWI. PMID:21640300

  13. Radionuclide removal

    SciTech Connect

    Sorg, T.J.

    1991-01-01

    The U.S. Environmental Protection Agency proposed new and revised regulations on radionuclide contaminants in drinking water in June 1991. During the 1980's, the Drinking Water Research Division, USEPA conducted a research program to evaluate various technologies to remove radium, uranium and radon from drinking water. The research consisted of laboratory and field studies conducted by USEPA, universities and consultants. The paper summarizes the results of the most significant projects completed. General information is also presented on the general chemistry of the three radionuclides. The information presented indicates that the most practical treatment methods for radium are ion exchange and lime-soda softening and reverse osmosis. The methods tested for radon are aeration and granular activated carbon and the methods for uranium are anion exchange and reverse osmosis.

  14. Three-region perfusion strategy for aortic arch reconstruction in the Norwood.

    PubMed

    Karavas, Alexandros N; Deschner, Benjamin W; Scott, John W; Mettler, Bret A; Bichell, David P

    2011-09-01

    We describe a new method of selective regional perfusion during arch reconstruction in the Norwood procedure. The strategy involves direct sequential perfusion of the coronary and splanchnic circulations coupled with continuous cerebral perfusion, while repairing the arch in a distal to proximal fashion. This technique provides the potential for decreased coronary and splanchnic ischemic times, which in combination with continuous selective cerebral perfusion may further allow for warmer operating temperatures and decreased overall bypass times.

  15. Neurovascular Regulation in the Ischemic Brain

    PubMed Central

    Jackman, Katherine

    2015-01-01

    Abstract Significance: The brain has high energetic requirements and is therefore highly dependent on adequate cerebral blood supply. To compensate for dangerous fluctuations in cerebral perfusion, the circulation of the brain has evolved intrinsic safeguarding measures. Recent Advances and Critical Issues: The vascular network of the brain incorporates a high degree of redundancy, allowing the redirection and redistribution of blood flow in the event of vascular occlusion. Furthermore, active responses such as cerebral autoregulation, which acts to maintain constant cerebral blood flow in response to changing blood pressure, and functional hyperemia, which couples blood supply with synaptic activity, allow the brain to maintain adequate cerebral perfusion in the face of varying supply or demand. In the presence of stroke risk factors, such as hypertension and diabetes, these protective processes are impaired and the susceptibility of the brain to ischemic injury is increased. One potential mechanism for the increased injury is that collateral flow arising from the normally perfused brain and supplying blood flow to the ischemic region is suppressed, resulting in more severe ischemia. Future Directions: Approaches to support collateral flow may ameliorate the outcome of focal cerebral ischemia by rescuing cerebral perfusion in potentially viable regions of the ischemic territory. Antioxid. Redox Signal. 22, 149–160. PMID:24328757

  16. Guidelines for brain radionuclide imaging. Perfusion single photon computed tomography (SPECT) using Tc-99m radiopharmaceuticals and brain metabolism positron emission tomography (PET) using F-18 fluorodeoxyglucose. The Belgian Society for Nuclear Medicine.

    PubMed

    Vander Borght, T; Laloux, P; Maes, A; Salmon, E; Goethals, I; Goldman, S

    2001-12-01

    The purpose of these guidelines is to assist nuclear medicine practitioners in recommending, performing, interpreting, and reporting the results of brain perfusion SPECT studies using Tc-99m radiopharmaceuticals and brain metabolism PET studies using F-18 fluorodeoxyglucose (FDG). These guidelines have been adapted and extended from those produced by the Society of Nuclear Medicine (Juni et al., 1998) and the European Association of Nuclear Medicine by a Belgian group of experts in the field trained in neurology and/or nuclear medicine. Some indications are not universally approved (e.g. brain death), but largely supported by the literature. They have been included in these guidelines in order to provide recommendations and a standardised protocol.

  17. Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography

    SciTech Connect

    Zannad, F.; Amor, M.; Karcher, G.; Maurin, P.; Ethevenot, G.; Sebag, C.; Bertrand, A.; Pernot, C.; Gilgenkrantz, J.M.

    1988-06-01

    Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute myocardial infarction.

  18. Anterior ischemic optic neuropathy following dengue fever.

    PubMed

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever.

  19. Anterior ischemic optic neuropathy following dengue fever

    PubMed Central

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever. PMID:27843231

  20. Ischemic postconditioning protects against ischemic brain injury by up-regulation of acid-sensing ion channel 2a

    PubMed Central

    Duanmu, Wang-sheng; Cao, Liu; Chen, Jing-yu; Ge, Hong-fei; Hu, Rong; Feng, Hua

    2016-01-01

    Ischemic postconditioning renders brain tissue tolerant to brain ischemia, thereby alleviating ischemic brain injury. However, the exact mechanism of action is still unclear. In this study, a rat model of global brain ischemia was subjected to ischemic postconditioning treatment using the vessel occlusion method. After 2 hours of ischemia, the bilateral common carotid arteries were blocked immediately for 10 seconds and then perfused for 10 seconds. This procedure was repeated six times. Ischemic postconditioning was found to mitigate hippocampal CA1 neuronal damage in rats with brain ischemia, and up-regulate acid-sensing ion channel 2a expression at the mRNA and protein level. These findings suggest that ischemic postconditioning up-regulates acid-sensing ion channel 2a expression in the rat hippocampus after global brain ischemia, which promotes neuronal tolerance to ischemic brain injury. PMID:27212927

  1. Ischemic Colitis

    PubMed Central

    FitzGerald, James F.; Hernandez III, Luis O.

    2015-01-01

    Most clinicians associate ischemic colitis with elderly patients who have underlying cardiovascular comorbidities. While the majority of cases probably occur in this population, the disease can present in younger patients as a result of different risk factors, making the diagnosis challenging. While a majority of patients respond to medical management, surgery is required in approximately 20% of the cases and is associated with high morbidity and mortality. PMID:26034405

  2. Reversible changes in diffusion- and perfusion-based imaging in cerebral venous sinus thrombosis.

    PubMed

    Lin, Ning; Wong, Andrew K; Lipinski, Lindsay J; Mokin, Maxim; Siddiqui, Adnan H

    2016-02-01

    Diffusion- and perfusion-based imaging studies are regularly used in patients with ischemic stroke. Cerebral venous sinus thrombosis (CVST) is a rare cause of stroke and is primarily treated by systemic anticoagulation. Endovascular intervention can be considered in cases of failed medical therapy, yet the prognostic value of diffusion- and perfusion-based imaging for CVST has not been clearly established. We present a patient with CVST whose abnormal findings on MRI and CT perfusion images were largely reversed after endovascular treatment.

  3. Prognostic value of radionuclide exercise testing after myocardial infarction

    SciTech Connect

    Schocken, D.D.

    1984-08-01

    Abnormal systolic ventricular function and persistent ischemia are sensitive indicators of poor prognosis following myocardial infarction. The use of exercise improves the utility of both radionuclide ventriculography and myocardial perfusion scintigraphy in the identification of postinfarction patients at high risk of subsequent cardiac events. 51 references.

  4. Hyperspectral imaging of ischemic wounds

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Elgharably, Haytham; Melvin, James; Huang, Kun; Bergdall, Valerie; Allen, David W.; Hwang, Jeeseong; Litorja, Maritoni; Shirley, Eric; Sen, Chandan K.; Xu, Ronald

    2012-03-01

    Optical imaging has the potential to achieve high spatial resolution and high functional sensitivity in wound assessment. However, clinical acceptance of many optical imaging devices is hampered by poor reproducibility, low accuracy, and lack of biological interpretation. We developed an in vivo model of ischemic flap for non-contact assessment of wound tissue functional parameters and spectral characteristics. The model was created by elevating the bipedicle skin flaps of a domestic pig from the underlying vascular bed and inhibiting graft bed reperfusion by a silastic sheet. Hyperspectral imaging was carried out on the ischemic flap model and compared with transcutaneous oxygen tension and perfusion measurements at different positions of the wound. Hyperspectral images have also been captured continuously during a post-occlusive reactive hyperemia (PORH) procedure. Tissue spectral characteristics obtained by hyperspectral imaging correlated well with cutaneous tissue oxygen tension, blood perfusion, and microscopic changes of tissue morphology. Our experiments not only demonstrated the technical feasibility for quantitative assessment of chronic wound but also provided a potential digital phantom platform for quantitative characterization and calibration of medical optical devices.

  5. Natural Radionuclides in Ground Water.

    ERIC Educational Resources Information Center

    Davis, Stanley N.

    1988-01-01

    Described are the natural trace radionuclides in ground water. Indicates the geologic origin of these radionuclides. Discusses the importance of these radionuclides. Suggests future uses of a number of additional radionuclides. (CW)

  6. Radionuclide deposition control

    DOEpatents

    Brehm, William F.; McGuire, Joseph C.

    1980-01-01

    The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.

  7. Assessment of Ischemic Cardiomyopathy Using Cardiovascular Magnetic Resonance Imaging: A Pictorial Review.

    PubMed

    Olivas-Chacon, Cristina Ivette; Mullins, Carola; Solberg, Agnieszka; Akle, Nassim; Calleros, Jesus E; Ramos-Duran, Luis R

    2015-01-01

    Ischemic heart disease is the leading cause of death worldwide. In the last two decades, cardiovascular magnetic resonance imaging (CMRI) has emerged as the primary imaging tool in the detection and prognostic assessment of ischemic heart disease. In a single study, CMRI allows evaluation of not only myocardial wall perfusion, but also the presence, acuity, and extent of myocardial ischemia and infarction complications. Also, rest and stress perfusion imaging can accurately depict inducible ischemia secondary to significant coronary artery stenosis. We present a pictorial review of the assessment of ischemic cardiomyopathy with an emphasis on CMRI features.

  8. Assessment of Ischemic Cardiomyopathy Using Cardiovascular Magnetic Resonance Imaging: A Pictorial Review

    PubMed Central

    Olivas-Chacon, Cristina Ivette; Mullins, Carola; Solberg, Agnieszka; Akle, Nassim; Calleros, Jesus E; Ramos-Duran, Luis R

    2015-01-01

    Ischemic heart disease is the leading cause of death worldwide. In the last two decades, cardiovascular magnetic resonance imaging (CMRI) has emerged as the primary imaging tool in the detection and prognostic assessment of ischemic heart disease. In a single study, CMRI allows evaluation of not only myocardial wall perfusion, but also the presence, acuity, and extent of myocardial ischemia and infarction complications. Also, rest and stress perfusion imaging can accurately depict inducible ischemia secondary to significant coronary artery stenosis. We present a pictorial review of the assessment of ischemic cardiomyopathy with an emphasis on CMRI features. PMID:26085960

  9. Quantitative Analysis of Peripheral Tissue Perfusion Using Spatiotemporal Molecular Dynamics

    PubMed Central

    Lee, Jungsul; Koh, Gou Young; Kwon, Kihwan; Choi, Chulhee

    2009-01-01

    Background Accurate measurement of peripheral tissue perfusion is challenging but necessary to diagnose peripheral vascular insufficiency. Because near infrared (NIR) radiation can penetrate relatively deep into tissue, significant attention has been given to intravital NIR fluorescence imaging. Methodology/Principal Findings We developed a new optical imaging-based strategy for quantitative measurement of peripheral tissue perfusion by time-series analysis of local pharmacokinetics of the NIR fluorophore, indocyanine green (ICG). Time-series NIR fluorescence images were obtained after injecting ICG intravenously in a murine hindlimb ischemia model. Mathematical modeling and computational simulations were used for translating time-series ICG images into quantitative pixel perfusion rates and a perfusion map. We could successfully predict the prognosis of ischemic hindlimbs based on the perfusion profiles obtained immediately after surgery, which were dependent on the preexisting collaterals. This method also reflected increases in perfusion and improvements in prognosis of ischemic hindlimbs induced by treatment with vascular endothelial growth factor and COMP-angiopoietin-1. Conclusions/Significance We propose that this novel NIR-imaging-based strategy is a powerful tool for biomedical studies related to the evaluation of therapeutic interventions directed at stimulating angiogenesis. PMID:19169354

  10. Special considerations in the pediatric use of radionuclides for kidney studies

    SciTech Connect

    Ash, J.M.; Antico, V.F.; Gilday, D.L.; Houle, S.

    1982-10-01

    Radionuclide renal studies are particularly well suited to pediatrics as renal problems in children usually are part of a dynamic process which requires serial assessment. The absence of side-effects and the low radiation dose has added to their popularity in pediatrics. A number of different renal parameters can be evaluated using the appropriate radiopharmaceutical and method of analysis. The renal study is of value to assess patients with hydronephrosis both pre-operatively and for serial follow-up post-operatively, as well as to distinguish obstructive from non-obstructive uropathy. Perfusion to the kidney may be assessed and ischemic areas detected in children with hypertension or trauma. The renal scan commonly is used in patients with congenital anomalies such as ectopic and duplex kidneys, nonvisualized kidney on IVP and in children with oliguria or anuria secondary to diseases such as acute tubular necrosis, hemolytic uremic syndrome, and renal vein thrombosis. It frequently is done as an emergency procedure in neonates. In conjunction with the IVP and ultrasound, the renal study is useful in some cases of abdominal mass to distinguish between hydronephrosis, cystic kidneys and tumors.

  11. Radionuclide bone imaging and densitometry

    SciTech Connect

    Mettler, F.A.

    1988-01-01

    This book contains 13 selections. Some of the titles are: Radionuclides and the Normal Bone Scan; The Radionuclide Bone Scan in Malignant Disease; Pediatric Applications of Radionuclide Bone Imaging; The Radionuclide Bone Scan in Arthritis and Metabolic and Miscellaneous Disorders; and Soft Tissue Activity on the Radionuclide Bone Scan.

  12. Ischemic Strokes (Clots)

    MedlinePlus

    ... Quiz 5 Things to Know About Stroke Ischemic Strokes (Clots) Updated:Nov 9,2016 Ischemic stroke accounts ... strokes. Read more about silent strokes . TIA and Stroke: Medical Emergencies When someone has shown symptoms of ...

  13. Preparation of Radiopharmaceuticals Labeled with Metal Radionuclides

    SciTech Connect

    Welch, M.J.

    2012-02-16

    The overall goal of this project was to develop methods for the production of metal-based radionuclides, to develop metal-based radiopharmaceuticals and in a limited number of cases, to translate these agents to the clinical situation. Initial work concentrated on the application of the radionuclides of Cu, Cu-60, Cu-61 and Cu-64, as well as application of Ga-68 radiopharmaceuticals. Initially Cu-64 was produced at the Missouri University Research Reactor and experiments carried out at Washington University. A limited number of studies were carried out utilizing Cu-62, a generator produced radionuclide produced by Mallinckrodt Inc. (now Covidien). In these studies, copper-62-labeled pyruvaldehyde Bis(N{sup 4}-methylthiosemicarbazonato)-copper(II) was studied as an agent for cerebral myocardial perfusion. A remote system for the production of this radiopharmaceutical was developed and a limited number of patient studies carried out with this agent. Various other copper radiopharmaceuticals were investigated, these included copper labeled blood imaging agents as well as Cu-64 labeled antibodies. Cu-64 labeled antibodies targeting colon cancer were translated to the human situation. Cu-64 was also used to label peptides (Cu-64 octriatide) and this is one of the first applications of a peptide radiolabeled with a positron emitting metal radionuclide. Investigations were then pursued on the preparation of the copper radionuclides on a small biomedical cyclotron. A system for the production of high specific activity Cu-64 was developed and initially the Cu-64 was utilized to study the hypoxic imaging agent Cu-64 ATSM. Utilizing the same target system, other positron emitting metal radionuclides were produced, these were Y-86 and Ga-66. Radiopharmaceuticals were labeled utilizing both of these radionuclides. Many studies were carried out in animal models on the uptake of Cu-ATSM in hypoxic tissue. The hypothesis is that Cu-ATSM retention in vivo is dependent upon the

  14. Radionuclide removal by apatite

    SciTech Connect

    Rigali, Mark J.; Brady, Patrick V.; Moore, Robert C.

    2016-12-01

    In this study, a growing body of research supports widespread future reliance on apatite for radioactive waste cleanup. Apatite is a multi-functional radionuclide sorbent that lowers dissolved radionuclide concentrations by surface sorption, ion exchange, surface precipitation, and by providing phosphate to precipitate low-solubility radionuclide-containing minerals. Natural apatites are rich in trace elements, and apatite’s stability in the geologic record suggest that radionuclides incorporated into apatite, whether in a permeable reactive barrier or a waste form, are likely to remain isolated from the biosphere for long periods of time. Here we outline the mineralogic and surface origins of apatite-radionuclide reactivity and show how apatites might be used to environmental advantage in the future.

  15. Radionuclide removal by apatite

    DOE PAGES

    Rigali, Mark J.; Brady, Patrick V.; Moore, Robert C.

    2016-12-01

    In this study, a growing body of research supports widespread future reliance on apatite for radioactive waste cleanup. Apatite is a multi-functional radionuclide sorbent that lowers dissolved radionuclide concentrations by surface sorption, ion exchange, surface precipitation, and by providing phosphate to precipitate low-solubility radionuclide-containing minerals. Natural apatites are rich in trace elements, and apatite’s stability in the geologic record suggest that radionuclides incorporated into apatite, whether in a permeable reactive barrier or a waste form, are likely to remain isolated from the biosphere for long periods of time. Here we outline the mineralogic and surface origins of apatite-radionuclide reactivity andmore » show how apatites might be used to environmental advantage in the future.« less

  16. Neutrophil gelatinase-associated lipocalin, a new biomarker candidate in perfusate of machine-perfused kidneys: a porcine pilot experiment.

    PubMed

    Jochmans, I; Monbaliu, D; Pirenne, J

    2011-11-01

    The enduring kidney graft shortage has led to the increasing use of expanded-criteria donors as well as kidneys donated after cardiac death, triggering the revival of machine perfusion preservation. Indeed, machine perfusion not only preserves these kidneys better than static cold storage, but also has the potential to evaluate them. The presence of certain biomarkers, among them aspartate aminotransferase (AST) and heart-type fatty acid binding protein (H-FABP), has been demonstrated in the perfusate of human kidneys, making them potentially useful as biomarkers of graft quality. Neutrophil gelatinase-associated lipocalin (NGAL) which is believed to be released upon renal tubular cell injury is another biomarker candidate. However, because it is also released from neutrophils, it is currently unclear whether NGAL is a direct or indirect, inflammatory-mediated marker of kidney injury. To resolve this issue we established a pilot experiment to study the concentrations of AST, H-FABP, and NGAL in the perfusates of 6 porcine kidneys that were exposed to incremental periods of warm ischemia before machine perfusion for 22 hours. An ex vivo porcine model was chosen because preclinical large animal work remains necessary to refine machine perfusion technology and because the presence of these markers in perfusates of porcine kidneys had not been shown previously. All 3 biomarkers were detectable in the cold acellular perfusate; their release seemed to be proportionate to the degree of warm injury, albeit that this must be confirmed in a larger sample. In conclusion, NGAL is directly released by ischemically damaged kidneys, independent of neutrophil activation. In addition to NGAL, the determination of AST and H-FABP in perfusates of machine-perfused porcine kidneys is also feasible. Determination of these markers may be added to the arsenal of research tools for preclinical preservation research.

  17. Acute ischemic preconditioning of skeletal muscle prior to flap elevation augments muscle-flap survival.

    PubMed

    Carroll, C M; Carroll, S M; Overgoor, M L; Tobin, G; Barker, J H

    1997-07-01

    Ischemic preconditioning of the myocardium with repeated brief periods of ischemia and reperfusion prior to prolonged ischemia significantly reduces subsequent myocardial infarction. Following ischemic preconditioning, two "windows of opportunity" (early and late) exist, during which time prolonged ischemia can occur with reduced infarction size. The early window occurs at approximately 4 hours and the late window at 24 hours following ischemic preconditioning of the myocardium. We investigated if ischemic preconditioning of skeletal muscle prior to flap creation improved subsequent flap survival and perfusion immediately or 24 hours following ischemic preconditioning. Currently, no data exist on the utilization of ischemic preconditioning in this fashion. The animal model used was the latissimus dorsi muscle of adult male Sprague-Dawley rats. Animals were assigned to three groups, and the right or left latissimus dorsi muscle was chosen randomly in each animal. Group 1 (n = 12) was the control group, in which the entire latissimus dorsi muscle was elevated acutely without ischemic preconditioning. Group 2 (n = 8) investigated the effects of ischemic preconditioning in the early window. In this group, the latissimus dorsi muscle was elevated immediately following preconditioning. Group 3 (n = 8) investigated the effects of ischemic preconditioning in the late window, with elevation of the latissimus dorsi muscle 24 hours following ischemic preconditioning. The preconditioning regimen used in groups 2 and 3 was two 30-minute episodes of normothermic global ischemia with intervening 10-minute episodes of reperfusion. Latissimus dorsi muscle ischemia was created by occlusion of the thoracodorsal artery and vein and the intercostal perforators, after isolation of the muscle on these vessels. Muscle perfusion was assessed by a laser-Doppler perfusion imager. One week after flap elevation, muscle necrosis was quantified in all groups by means of computer-assisted digital

  18. Drug Delivery to the Ischemic Brain

    PubMed Central

    Thompson, Brandon J.; Ronaldson, Patrick T.

    2014-01-01

    Cerebral ischemia occurs when blood flow to the brain is insufficient to meet metabolic demand. This can result from cerebral artery occlusion that interrupts blood flow, limits CNS supply of oxygen and glucose, and causes an infarction/ischemic stroke. Ischemia initiates a cascade of molecular events inneurons and cerebrovascular endothelial cells including energy depletion, dissipation of ion gradients, calcium overload, excitotoxicity, oxidative stress, and accumulation of ions and fluid. Blood-brain barrier (BBB) disruption is associated with cerebral ischemia and leads to vasogenic edema, a primary cause of stroke-associated mortality. To date, only a single drug has received US Food and Drug Administration (FDA) approval for acute ischemic stroke treatment, recombinant tissue plasminogen activator (rt-PA). While rt-PA therapy restores perfusion to ischemic brain, considerable tissue damage occurs when cerebral blood flow is re-established. Therefore, there is a critical need for novel therapeutic approaches that can “rescue” salvageable brain tissue and/or protect BBB integrity during ischemic stroke. One class of drugs that may enable neural cell rescue following cerebral ischemia/reperfusion injury is the HMG-CoA reductase inhibitors (i.e., statins). Understanding potential CNS drug delivery pathways for statins is critical to their utility in ischemic stroke. Here, we review molecular pathways associated with cerebral ischemia and novel approaches for delivering drugs to treat ischemic disease. Specifically, we discuss utility of endogenous BBB drug uptake transporters such as organic anion transporting polypeptides (OATPs/Oatps) and nanotechnology-based carriers for optimization of CNS drug delivery. Overall, this chapter highlights state-of-the-art technologies that may improve pharmacotherapy of cerebral ischemia. PMID:25307217

  19. Radionuclides in US coals

    SciTech Connect

    Bisselle, C. A.; Brown, R. D.

    1984-03-01

    The current state of knowledge with respect to radionuclide concentrations in US coals is discussed. Emphasis is placed on the levels of uranium in coal (and lignite) which are considered to represent a concern resulting from coal combustion; areas of the US where such levels have been found; and possible origins of high radionuclide levels in coal. The report reviews relevant studies and presents new data derived from a computerized search of radionuclide content in about 4000 coal samples collected throughout the coterminous US. 103 references, 5 figures, 5 tables.

  20. Relationships between perfusion defects and static brain scan positivity in patients with ischaemic completed stroke: considerations about the origin of the increased uptake

    PubMed Central

    Bartolini, Alfredo

    1982-01-01

    The relation between perfusion defects shown by radionuclide angiography and static brain scan positivity was evaluated in patients with ischaemic completed stroke at various intervals from the onset of symptoms. An inverse relation between radionuclide angiography and static scan positivity was found for the period within 15 days of the onset of symptoms. The possible relation between changes in perfusion and static brain scan positivity is discussed. PMID:6279782

  1. Xanthine oxidase inhibition attenuates ischemic-reperfusion lung injury

    SciTech Connect

    Lynch, M.J.; Grum, C.M.; Gallagher, K.P.; Bolling, S.F.; Deeb, G.M.; Morganroth, M.L.

    1988-05-01

    Ischemic-reperfusion lung injury is a factor potentially limiting the usefulness of distant organ procurement for heart-lung transplantation. Toxic oxygen metabolites are considered a major etiologic factor in reperfusion injury. Although oxygen-free radicals may be generated by many mechanisms, we investigated the role of xanthine oxidase in this injury process by using lodoxamide, a xanthine oxidase inhibitor, to inhibit ischemic-reperfusion injury in an isolated rat lung model. Isolated rat lungs were perfused with physiologic salt solution (PSS) osmotically stabilized with Ficoll until circulating blood elements were nondetectable in the pulmonary venous effluent. Lungs were rendered ischemic by interrupting ventilation and perfusion for 2 hr at 37/sup 0/C. After the ischemic interval, the lungs were reperfused with whole blood and lung injury was determined by measuring the accumulation of /sup 125/I-bovine serum albumin in lung parenchyma and alveolar lavage fluid as well as by gravimetric measurements. Lung effluent was collected immediately pre- and postischemia for analysis of uric acid by high-pressure liquid chromatography. Lodoxamide (1 mM) caused significant attenuation of postischemic lung injury. Uric acid levels in the lung effluent confirmed inhibition of xanthine oxidase. Protection from injury was not complete, however, implying that additional mechanisms may contribute to ischemic-reperfusion injury in the lung.

  2. Intracoronary Delivery of Mitochondria to the Ischemic Heart for Cardioprotection

    PubMed Central

    Cowan, Douglas B.; Yao, Rouan; Akurathi, Vamsidhar; Snay, Erin R.; Thedsanamoorthy, Jerusha K.; Zurakowski, David; Ericsson, Maria; Friehs, Ingeborg; Wu, Yaotang; Levitsky, Sidney; del Nido, Pedro J.; Packard, Alan B.

    2016-01-01

    We have previously shown that transplantation of autologously derived, respiration-competent mitochondria by direct injection into the heart following transient ischemia and reperfusion enhances cell viability and contractile function. To increase the therapeutic potential of this approach, we investigated whether exogenous mitochondria can be effectively delivered through the coronary vasculature to protect the ischemic myocardium and studied the fate of these transplanted organelles in the heart. Langendorff-perfused rabbit hearts were subjected to 30 minutes of ischemia and then reperfused for 10 minutes. Mitochondria were labeled with 18F-rhodamine 6G and iron oxide nanoparticles. The labeled mitochondria were either directly injected into the ischemic region or delivered by vascular perfusion through the coronary arteries at the onset of reperfusion. These hearts were used for positron emission tomography, microcomputed tomography, and magnetic resonance imaging with subsequent microscopic analyses of tissue sections to confirm the uptake and distribution of exogenous mitochondria. Injected mitochondria were localized near the site of delivery; while, vascular perfusion of mitochondria resulted in rapid and extensive dispersal throughout the heart. Both injected and perfused mitochondria were observed in interstitial spaces and were associated with blood vessels and cardiomyocytes. To determine the efficacy of vascular perfusion of mitochondria, an additional group of rabbit hearts were subjected to 30 minutes of regional ischemia and reperfused for 120 minutes. Immediately following regional ischemia, the hearts received unlabeled, autologous mitochondria delivered through the coronary arteries. Autologous mitochondria perfused through the coronary vasculature significantly decreased infarct size and significantly enhanced post-ischemic myocardial function. In conclusion, the delivery of mitochondria through the coronary arteries resulted in their rapid

  3. Radionuclides in Diagnosis.

    ERIC Educational Resources Information Center

    Williams, E. D.

    1989-01-01

    Discussed is a radionuclide imaging technique, including the gamma camera, image analysis computer, radiopharmaceuticals, and positron emission tomography. Several pictures showing the use of this technique are presented. (YP)

  4. Excorporeal Normothermic Machine Perfusion Resuscitates Pig DCD Livers with Extended Warm Ischemia

    PubMed Central

    Xu, Hongzhi; Berendsen, Tim; Kim, Karen; Soto-Gutiérrez, Alejandro; Bertheium, Francios; Yarmush, Martin L.; Hertl, Martin

    2013-01-01

    Background The shortage in donor livers has led to increased use of allografts derived from donation after cardiac death (DCD). The compromised viability in these livers leads to inferior post-transplantation allograft function and survival compared with donation after brain death (DBD) donor grafts. In this study, we reconditioned DCD livers using an optimized normothermic machine perfusion system. Methods Livers from 12 Yorkshire pigs (20–30 kg) were subjected to either 0 min (WI-0 group, n = 6) or 60 min (WI-60 group, n = 6) of warm ischemia and 2 h of cold storage in UW solution, followed by 4 h of oxygenated sanguineous normothermic machine perfusion. Liver viability and metabolic function were analyzed hourly. Results Warm ischemic livers showed elevated transaminase levels and reduced ATP concentration. After the start of machine perfusion, transaminase levels stabilized and there was recovery of tissue ATP, coinciding with an increase in bile production. These parameters reached comparable levels to the control group after 1 h of machine perfusion. Histology and gross morphology confirmed recovery of the ischemic allografts. Conclusion Our data demonstrate that metabolic and functional parameters of livers with extended warm ischemic time (60 min) can be significantly improved using normothermic machine perfusion. We hereby compound the existing body of evidence that machine perfusion is a viable solution for reconditioning marginal organs. PMID:22099594

  5. Computed tomography perfusion imaging in spectacular shrinking deficit.

    PubMed

    Lee, Vivien H; John, Sayona; Mohammad, Yousef; Prabhakaran, Shyam

    2012-02-01

    Spectacular shrinking deficit (SSD) is characterized by abrupt onset of a major hemispheric stroke syndrome, followed by dramatic and rapid improvement. We retrospectively identified patients with SSD diagnosed at our institution between December 1, 2007, and June 30, 2009. We reviewed computed tomography perfusion (CTP) imaging to determine perfusion defect as a measure of initial ischemic penumbra, and magnetic resonance imaging diffusion-weighted imaging (DWI) to determine the final infarct core. Among the 472 consecutive ischemic stroke patients, 126 (27%) presented with major hemispheric ischemic stroke syndrome, defined as National Institutes of Health Stroke Scale score (NIHSS) ≥8 in the territory of the middle cerebral artery (MCA) or internal carotid artery (ICA). Out of these patients, we identified 8 SSD patients with available CTP data. In these 8 patients, the mean time to dramatic recovery was 3.4 hours (range, 0.75-7 hours), and the mean time from onset to CTP was 12.7 hours (range, 3-30 hours). All 8 patients had perfusion abnormalities in portions of the MCA territory (partial MCA territory in 5 patients and complete MCA territory in 3 patients). The mean time from onset to MRI DWI was 15.5 hours (range, 7.9-34 hours). Restricted diffusion was present in all patients in the corresponding MCA distribution. Vascular imaging revealed MCA occlusion in 2 patients. Cervical vascular imaging revealed carotid occlusion in 2 patients and high-grade carotid stenosis in 2 patients. The stroke mechanisms were cardioembolism in 2 patients, large artery in 4 patients, and unknown in 2 patients. Four patients had repeat CTP imaging available that demonstrated eventual resolution of the perfusion defect. SSD is associated with a "shrinking" clinical syndrome and a "shrinking" perfusion pattern on CTP that lags behind clinical recovery. CTP imaging corroborates that a larger territory is at risk in SSD and contributes to better understanding of SSD.

  6. Method and apparatus for separating radionuclides from non-radionuclides

    DOEpatents

    Harp, Richard J.

    1990-01-01

    In an apparatus for separating radionuclides from non-radionuclides in a mixture of nuclear waste, a vessel is provided wherein the mixture is heated to a temperature greater than the temperature of vaporization for the non-radionuclides but less than the temperature of vaporization for the radionuclides. Consequently the non-radionuclides are vaporized while the non-radionuclides remain the solid or liquid state. The non-radionuclide vapors are withdrawn from the vessel and condensed to produce a flow of condensate. When this flow decreases the heat is reduced to prevent temperature spikes which might otherwise vaporize the radionuclides. The vessel is removed and capped with the radioactive components of the apparatus and multiple batches of the radionuclide residue disposed therein. Thus the vessel ultimately provides a burial vehicle for all of the radioactive components of the process.

  7. Abdominal perfusion computed tomography.

    PubMed

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-02-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis.

  8. Abdominal Perfusion Computed Tomography

    PubMed Central

    Ogul, Hayri; Bayraktutan, Ummugulsum; Kizrak, Yesim; Pirimoglu, Berhan; Yuceler, Zeynep; Sagsoz, M. Erdem; Yilmaz, Omer; Aydinli, Bulent; Ozturk, Gurkan; Kantarci, Mecit

    2013-01-01

    The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis. PMID:25610249

  9. Delayed redistribution in thallium 201 SPECT myocardial perfusion studies

    SciTech Connect

    Ziessman, H.A.; Keyes, J.W. Jr.; Fox, L.M.; Green, C.E.; Fox, S.M. )

    1989-11-01

    Stress {sup 201}Tl myocardial perfusion studies are useful in differentiating viable, reversibly ischemic from infarcted myocardium. A perfusion defect that shows redistribution 2 to 4 h after {sup 201}Tl injection is diagnostic of ischemia, while a fixed defect suggests infarction. However, occasional patients with a fixed defect at 4 h have redistribution at 24 h. This study evaluates the frequency and significance of this delayed redistribution with SPECT {sup 201}Tl. Patients with either no or incomplete redistribution at 4 h had repeat imaging 18 to 48 h later. Delayed redistribution was seen in 8/26 (31 percent). Four had incomplete and four had no redistribution at 4 h. Delayed redistribution with SPECT {sup 201}Tl is more common than generally appreciated, and we recommend delayed images in patients with fixed perfusion defects or incomplete redistribution at 4-h imaging, particularly in patients with previous infarctions for whom a revascularization procedure is being considered.

  10. Utility of CT perfusion scanning in patient selection for acute stroke intervention: experience at University at Buffalo Neurosurgery-Millard Fillmore Gates Circle Hospital.

    PubMed

    Kan, Peter T; Snyder, Kenneth V; Yashar, Parham; Siddiqui, Adnan H; Hopkins, L Nelson; Levy, Elad I

    2011-06-01

    Computed tomography perfusion scanning generates physiological flow parameters of the brain parenchyma, allowing differentiation of ischemic penumbra and core infarct. Perfusion maps, along with the National Institutes of Health Stroke Scale score, are used as the bases for endovascular stroke intervention at the authors' institute, regardless of the time interval from stroke onset. With case examples, the authors illustrate their perfusion-based imaging guidelines in patient selection for endovascular treatment in the setting of acute stroke.

  11. SPECT and PET in ischemic heart failure.

    PubMed

    Angelidis, George; Giamouzis, Gregory; Karagiannis, Georgios; Butler, Javed; Tsougos, Ioannis; Valotassiou, Varvara; Giannakoulas, George; Dimakopoulos, Nikolaos; Xanthopoulos, Andrew; Skoularigis, John; Triposkiadis, Filippos; Georgoulias, Panagiotis

    2017-02-02

    Heart failure is a common clinical syndrome associated with significant morbidity and mortality worldwide. Ischemic heart disease is the leading cause of heart failure, at least in the industrialized countries. Proper diagnosis of the syndrome and management of patients with heart failure require anatomical and functional information obtained through various imaging modalities. Nuclear cardiology techniques play a main role in the evaluation of heart failure. Myocardial single photon emission computed tomography (SPECT) with thallium-201 or technetium-99 m labelled tracers offer valuable data regarding ventricular function, myocardial perfusion, viability, and intraventricular synchronism. Moreover, positron emission tomography (PET) permits accurate evaluation of myocardial perfusion, metabolism, and viability, providing high-quality images and the ability of quantitative analysis. As these imaging techniques assess different parameters of cardiac structure and function, variations of sensitivity and specificity have been reported among them. In addition, the role of SPECT and PET guided therapy remains controversial. In this comprehensive review, we address these controversies and report the advances in patient's investigation with SPECT and PET in ischemic heart failure. Furthermore, we present the innovations in technology that are expected to strengthen the role of nuclear cardiology modalities in the investigation of heart failure.

  12. Sensitivity to acute cerebral ischemic injury in migraineurs

    PubMed Central

    Mawet, Jerome; Eikermann-Haerter, Katharina; Park, Kwang-Yeol; Helenius, Johanna; Daneshmand, Ali; Pearlman, Lea; Avery, Ross; Negro, Andrea; Velioglu, Murat; Arsava, Ethem Murat

    2015-01-01

    Objective: Migraine, particularly with aura, is a risk factor for ischemic stroke. Recent data in migraine mutant mice suggest that cerebral hyperexcitability associated with migraine accelerates recruitment of ischemic penumbra into the core, resulting in faster infarct growth compared with wild type. We hypothesized that individuals with a history of migraine are more likely to exhibit increased recruitment of ischemic tissue into the infarct in acute stroke. Methods: In this retrospective case-control study, we identified participants with reliably documented migraine history, measured lesion volumes on diffusion-weighted and perfusion-weighted MRI obtained within 72 hours of symptom onset, calculated the proportion of ischemic tissue on perfusion-weighted imaging (PWI) hyperintense on diffusion-weighted imaging (DWI), and compared the proportion of patients with no-mismatch pattern defined as DWI lesion >83% of PWI lesion. Results: Migraineurs (n = 45) were younger, more often female, less likely to have vascular risk factors, and more often had cervical artery dissection, but otherwise did not differ from controls (n = 27). A significantly larger proportion of migraineurs had no-mismatch pattern, indicating that the entire perfusion defect was recruited into the infarct by the time of MRI (22% vs 4% of migraineurs and controls, respectively; p = 0.044). The difference was even more prominent in migraineurs with aura (36% vs 4%, p = 0.019). The association between migraine and no-mismatch pattern persisted after adjustment for time to MRI (p = 0.041). Conclusions: This case-control study supports the hypothesis that a history of migraine, particularly with aura, is associated with a no-mismatch pattern during acute ischemic stroke, consistent with data obtained in migraine mutant mice. PMID:26537055

  13. The role of radionuclide imaging in heart failure.

    PubMed

    Gulati, Vinay; Ching, Gilbert; Heller, Gary V

    2013-12-01

    The incidence of heart failure (HF) is increasing and it remains the only area in cardiovascular disease wherein hospitalization rates and mortalities have worsened in the past 25 years. This review is provided to assess the role of radionuclide imaging in HF. The focus is on three aspects: the value of nuclear imaging to distinguish ischemic from non-ischemic etiologies; risk stratification of patients with HF with evaluation of candidates for specific treatment strategies; and the role of cardiac neuronal imaging in patients with HF. Distinguishing ischemic from non-ischemic cardiomyopathy is important because patients with ischemic cardiomyopathy can potentially have dramatic improvement with revascularization. Single photon emission computed tomography (SPECT) has excellent reported sensitivity and negative predictive value in the detection of coronary artery disease in HF patients. SPECT imaging is also useful in establishing treatment strategies in patients with HF, including those with new onset CHF. Cardiac neuronal imaging of mIBG is particularly helpful in risk stratification of patients with HF. The modality can be used to monitor the response to therapy as dysfunctional mIBG uptake may show improvement with pharmacological treatment.

  14. Initial Radionuclide Inventories

    SciTech Connect

    H. Miller

    2004-09-19

    The purpose of this analysis is to provide an initial radionuclide inventory (in grams per waste package) and associated uncertainty distributions for use in the Total System Performance Assessment for the License Application (TSPA-LA) in support of the license application for the repository at Yucca Mountain, Nevada. This document is intended for use in postclosure analysis only. Bounding waste stream information and data were collected that capture probable limits. For commercially generated waste, this analysis considers alternative waste stream projections to bound the characteristics of wastes likely to be encountered using arrival scenarios that potentially impact the commercial spent nuclear fuel (CSNF) waste stream. For TSPA-LA, this radionuclide inventory analysis considers U.S. Department of Energy (DOE) high-level radioactive waste (DHLW) glass and two types of spent nuclear fuel (SNF): CSNF and DOE-owned (DSNF). These wastes are placed in two groups of waste packages: the CSNF waste package and the codisposal waste package (CDSP), which are designated to contain DHLW glass and DSNF, or DHLW glass only. The radionuclide inventory for naval SNF is provided separately in the classified ''Naval Nuclear Propulsion Program Technical Support Document'' for the License Application. As noted previously, the radionuclide inventory data presented here is intended only for TSPA-LA postclosure calculations. It is not applicable to preclosure safety calculations. Safe storage, transportation, and ultimate disposal of these wastes require safety analyses to support the design and licensing of repository equipment and facilities. These analyses will require radionuclide inventories to represent the radioactive source term that must be accommodated during handling, storage and disposition of these wastes. This analysis uses the best available information to identify the radionuclide inventory that is expected at the last year of last emplacement, currently identified as

  15. Radionuclide studies in impotence

    SciTech Connect

    Hilson, A.J.; Lewis, C.A. )

    1991-04-01

    Impotence may be of physiological origin with causes including vascular or neurological pathology. Alternatively, it may be of psychogenic origin. Clinicians can distinguish between psychological and organic impotence by observing nocturnal penile tumescence. Non-radionuclide investigations for organic impotence include penile plethysmography or pulse Doppler analysis for arterial supply, cavernosometry for venous drainage, and biothesiometry or evoked potentials for neurological pathology. Radionuclide studies are primarily based on the use of technetium 99m-pertechnetate, 99mTc-red blood cells, or xenon 133 to study the blood flow, with or without pharmacological intervention, commonly papaverine. 26 references.

  16. Hyperpolarized 129Xe magnetic resonance imaging of a rat model of transient Ischemic Stroke

    NASA Astrophysics Data System (ADS)

    Walvick, Ronn P.; Bastan, Birgul; Reno, Austin; Mansour, Joey; Sun, Yanping; Zhou, Xin; Mazzani, Mary; Fisher, Marc; Sotak, Christopher H.; Albert, Mitchell S.

    2009-02-01

    Ischemic stroke accounts for nearly 80% of all stroke cases. Although proton diffusion and perfusion magnetic resonance imaging (MRI) are the gold standards in ischemic stroke diagnostics, the use of hyperpolarized 129Xe MRI has a potential role to contribute to the diagnostic picture. The highly lipophilic hyperpolarized 129Xe can be non-invasively delivered via inhalation into the lungs where it is dissolved into the blood and delivered to other organs such as the brain. As such, we expect hyperpolarized 129Xe to act as a perfusion tracer which will result in a signal deficit in areas of blood deprived tissue. In this work, we present imaging results from an animal model of transient ischemic stroke characterized through 129Xe MRI. In this model, a suture is used to occlude the middle cerebral artery (MCA) in the rat brain, thus causing an ischemic event. After a period of MCA occlusion, the suture can then be removed to reperfuse the ischemic area. During the ischemic phase of the stroke, a signal void was observed in the MCA territory; which was subsequently restored by normal 129Xe MRI signal once perfusion was reinstated. Further, a higher resolution one-dimensional chemical shift image shows a sharp signal drop in the area of ischemia. Validation of ischemic damage was shown through both proton diffusion-weighted MRI (DWI) and by 2,3,5-triphenyltetrazoliumchloride (TTC) staining. The results show the potential of 129Xe to act as a perfusion tracer; information that may add to the diagnostic and prognostic utility of the clinical picture of stroke.

  17. Transient ischemic attack may present a target for normobaric hyperoxia treatment.

    PubMed

    Hadjiev, Dimiter I; Mineva, Petya P

    2010-07-01

    According to the new revised tissue-based definition, transient ischemic attack is a transient episode of neurological dysfunction caused by a focal brain, spinal cord, or retinal ischemia without acute infarction. This review addresses the pathophysiology of transient ischemic attack and the impact of normobaric hyperoxia on the penumbral tissue. Neuroimaging in transient ischemic attack patients and advances in penumbra imaging allow the transient ischemic attack, from pathophysiological viewpoint, to be defined as an ischemic penumbra of varied duration, which could proceed to a cerebral infarction or reduce to a benign oligemia. Persisting perfusion abnormalities are observed, despite resolution of the neurological symptoms. Preclinical and clinical studies have shown that the normobaric hyperoxia treatment is associated with improvement of hemodynamic and metabolic disturbances, particularly in the penumbral tissue. Transient ischemic attack, considered an ischemic penumbra, may present an ideal target for early normobaric hyperoxia therapy, administered as soon as possible after the onset of the neurological deficit. Follow-up perfusion imaging could guide and individualize the treatment.

  18. Elevated blood pressure management in acute ischemic stroke remains controversial: could this issue be resolved?

    PubMed

    Hadjiev, Dimiter I; Mineva, Petya P

    2013-01-01

    A transient elevated arterial blood pressure is common in acute ischemic stroke and is often associated with a poor prognosis. The underlying mechanisms of blood pressure elevation are not well understood and its management is still unresolved. This article focuses on pathophysiology and management of elevated blood pressure in acute ischemic stroke. There is evidence that the main causes of a transient blood pressure elevation in acute ischemic stroke are the focal cerebral hypoperfusion and the stress responses with neuroendocrine systems activation. Clinical trials have reported that blood pressure lowering in acute ischemic stroke may have detrimental effect, probably because of impaired cerebral autoregulation. However, quantitative assessment of cerebral perfusion has not been performed during emergency blood pressure reduction in acute ischemic stroke. We suggest that ultrasound carotid artery disease evaluation and cerebral hemodynamics monitoring using bilateral transcranial ultrasonography, during blood pressure management in acute ischemic stroke might contribute to maintaining of an adequate penumbral perfusion and prevent infarct enlargement. Such an approach could individualize the antihypertensive treatment in acute ischemic stroke and improve functional outcome. Prospective studies are needed to confirm such a treatment strategy.

  19. Quantitative myocardial perfusion SPECT.

    PubMed

    Tsui, B M; Frey, E C; LaCroix, K J; Lalush, D S; McCartney, W H; King, M A; Gullberg, G T

    1998-01-01

    In recent years, there has been much interest in the clinical application of attenuation compensation to myocardial perfusion single photon emission computed tomography (SPECT) with the promise that accurate quantitative images can be obtained to improve clinical diagnoses. The different attenuation compensation methods that are available create confusion and some misconceptions. Also, attenuation-compensated images reveal other image-degrading effects including collimator-detector blurring and scatter that are not apparent in uncompensated images. This article presents basic concepts of the major factors that degrade the quality and quantitative accuracy of myocardial perfusion SPECT images, and includes a discussion of the various image reconstruction and compensation methods and misconceptions and pitfalls in implementation. The differences between the various compensation methods and their performance are demonstrated. Particular emphasis is directed to an approach that promises to provide quantitative myocardial perfusion SPECT images by accurately compensating for the 3-dimensional (3-D) attenuation, collimator-detector response, and scatter effects. With advances in the computer hardware and optimized implementation techniques, quantitatively accurate and high-quality myocardial perfusion SPECT images can be obtained in clinically acceptable processing time. Examples from simulation, phantom, and patient studies are used to demonstrate the various aspects of the investigation. We conclude that quantitative myocardial perfusion SPECT, which holds great promise to improve clinical diagnosis, is an achievable goal in the near future.

  20. Magnetic resonance cardiac perfusion imaging-a clinical perspective.

    PubMed

    Hunold, Peter; Schlosser, Thomas; Barkhausen, Jörg

    2006-08-01

    Coronary artery disease (CAD) with its clinical appearance of stable or unstable angina and acute myocardial infarction is the leading cause of death in developed countries. In view of increasing costs and the rising number of CAD patients, there has been a major interest in reliable non-invasive imaging techniques to identify CAD in an early (i.e. asymptomatic) stage. Since myocardial perfusion deficits appear very early in the "ischemic cascade", a major breakthrough would be the non-invasive quantification of myocardial perfusion before functional impairment might be detected. Therefore, there is growing interest in other, target-organ-specific parameters, such as relative and absolute myocardial perfusion imaging. Magnetic resonance (MR) imaging has been proven to offer attractive concepts in this respect. However, some important difficulties have not been resolved so far, which still causes uncertainty and prevents the broad application of MR perfusion imaging in a clinical setting. This review explores recent technical developments in MR hardware, software and contrast agents, as well as their impact on the current and future clinical status of MR imaging of first-pass myocardial perfusion imaging.

  1. Gallbladder radionuclide scan

    MedlinePlus

    ... please enable JavaScript. Gallbladder radionuclide scan is a test that uses radioactive material to check gallbladder function. It is also used ... for bile duct blockage or leak. How the Test is Performed ... called a gamma emitting tracer into a vein. This material collects mostly in the liver. It will then ...

  2. In vivo characterization of ischemic small intestine using bioimpedance measurements.

    PubMed

    Strand-Amundsen, R J; Tronstad, C; Kalvøy, H; Gundersen, Y; Krohn, C D; Aasen, A O; Holhjem, L; Reims, H M; Martinsen, Ø G; Høgetveit, J O; Ruud, T E; Tønnessen, T I

    2016-02-01

    The standard clinical method for the assessment of viability in ischemic small intestine is still visual inspection and palpation. This method is non-specific and unreliable, and requires a high level of clinical experience. Consequently, viable tissue might be removed, or irreversibly damaged tissue might be left in the body, which may both slow down patient recovery. Impedance spectroscopy has been used to measure changes in electrical parameters during ischemia in various tissues. The physical changes in the tissue at the cellular and structural levels after the onset of ischemia lead to time-variant changes in the electrical properties. We aimed to investigate the use of bioimpedance measurement to assess if the tissue is ischemic, and to assess the ischemic time duration. Measurements were performed on pigs (n = 7) using a novel two-electrode setup, with a Solartron 1260/1294 impedance gain-phase analyser. After induction of anaesthesia, an ischemic model with warm, full mesenteric arterial and venous occlusion on 30 cm of the jejunum was implemented. Electrodes were placed on the serosal surface of the ischemic jejunum, applying a constant voltage, and measuring the resulting electrical admittance. As a control, measurements were done on a fully perfused part of the jejunum in the same porcine model. The changes in tan δ (dielectric parameter), measured within a 6 h period of warm, full mesenteric occlusion ischemia in seven pigs, correlates with the onset and duration of ischemia. Tan δ measured in the ischemic part of the jejunum differed significantly from the control tissue, allowing us to determine if the tissue was ischemic or not (P < 0.0001, F = (1,75.13) 188.19). We also found that we could use tan δ to predict ischemic duration. This opens up the possibility of real-time monitoring and assessment of the presence and duration of small intestinal ischemia.

  3. Ex vivo lung perfusion.

    PubMed

    Reeb, Jeremie; Cypel, Marcelo

    2016-03-01

    Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation.

  4. [Portable peristaltic perfusion pumps].

    PubMed

    Magallón Pedrera, I; Soto Torres, I

    1999-11-01

    Portable peristaltic perfusion pumps allow one to administer pharmaceuticals in hospitals as well as in primary health care centers and furthermore these pumps present multiple advantages for patients and their families since they make it possible to carry out treatment in a patient's home while at the same time lowering the costs involved. The authors analyze the most out standing aspects of portable peristaltic perfusion pumps along with their characteristics, installation, programming, and how to turn them on; in addition, the authors list the maintenance care which these pumps require.

  5. EBS Radionuclide Transport Abstraction

    SciTech Connect

    R. Schreiner

    2001-06-27

    The purpose of this work is to develop the Engineered Barrier System (EBS) radionuclide transport abstraction model, as directed by a written development plan (CRWMS M&O 1999a). This abstraction is the conceptual model that will be used to determine the rate of release of radionuclides from the EBS to the unsaturated zone (UZ) in the total system performance assessment-license application (TSPA-LA). In particular, this model will be used to quantify the time-dependent radionuclide releases from a failed waste package (WP) and their subsequent transport through the EBS to the emplacement drift wall/UZ interface. The development of this conceptual model will allow Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department to provide a more detailed and complete EBS flow and transport abstraction. The results from this conceptual model will allow PA0 to address portions of the key technical issues (KTIs) presented in three NRC Issue Resolution Status Reports (IRSRs): (1) the Evolution of the Near-Field Environment (ENFE), Revision 2 (NRC 1999a), (2) the Container Life and Source Term (CLST), Revision 2 (NRC 1999b), and (3) the Thermal Effects on Flow (TEF), Revision 1 (NRC 1998). The conceptual model for flow and transport in the EBS will be referred to as the ''EBS RT Abstraction'' in this analysis/modeling report (AMR). The scope of this abstraction and report is limited to flow and transport processes. More specifically, this AMR does not discuss elements of the TSPA-SR and TSPA-LA that relate to the EBS but are discussed in other AMRs. These elements include corrosion processes, radionuclide solubility limits, waste form dissolution rates and concentrations of colloidal particles that are generally represented as boundary conditions or input parameters for the EBS RT Abstraction. In effect, this AMR provides the algorithms for transporting radionuclides using the flow geometry and radionuclide concentrations determined by other

  6. EBS Radionuclide Transport Abstraction

    SciTech Connect

    J. Prouty

    2006-07-14

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers advective transport and diffusive transport

  7. Lubiprostone induced ischemic colitis.

    PubMed

    Sherid, Muhammed; Sifuentes, Humberto; Samo, Salih; Deepak, Parakkal; Sridhar, Subbaramiah

    2013-01-14

    Ischemic colitis accounts for 6%-18% of the causes of acute lower gastrointestinal bleeding. It is often multifactorial and more commonly encountered in the elderly. Several medications have been implicated in the development of colonic ischemia. We report a case of a 54-year old woman who presented with a two-hour history of nausea, vomiting, abdominal pain, and bloody stool. The patient had recently used lubiprostone with close temporal relationship between the increase in the dose and her symptoms of rectal bleeding. The radiologic, colonoscopic and histopathologic findings were all consistent with ischemic colitis. Her condition improved without any serious complications after the cessation of lubiprostone. This is the first reported case of ischemic colitis with a clear relationship with lubiprostone (Naranjo score of 10). Clinical vigilance for ischemic colitis is recommended for patients receiving lubiprostone who are presenting with abdominal pain and rectal bleeding.

  8. Myocardial perfusion echocardiography and coronary microvascular dysfunction

    PubMed Central

    Barletta, Giuseppe; Del Bene, Maria Riccarda

    2015-01-01

    Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation, but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography (MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction, respectively, and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall, MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice, but the approval of regulatory authorities is lacking. PMID:26730291

  9. Phase I and Phase II Therapies for Acute Ischemic Stroke: An Update on Currently Studied Drugs in Clinical Research

    PubMed Central

    Reis, Cesar; Akyol, Onat; Ho, Wing Mann; Araujo, Camila; Huang, Lei; Applegate II, Richard

    2017-01-01

    Acute ischemic stroke is a devastating cause of death and disability, consequences of which depend on the time from ischemia onset to treatment, the affected brain region, and its size. The main targets of ischemic stroke therapy aim to restore tissue perfusion in the ischemic penumbra in order to decrease the total infarct area by maintaining blood flow. Advances in research of pathological process and pathways during acute ischemia have resulted in improvement of new treatment strategies apart from restoring perfusion. Additionally, limiting the injury severity by manipulating the molecular mechanisms during ischemia has become a promising approach, especially in animal research. The purpose of this article is to review completed and ongoing phases I and II trials for the treatment of acute ischemic stroke, reviewing studies on antithrombotic, thrombolytic, neuroprotective, and antineuroinflammatory drugs that may translate into more effective treatments. PMID:28286764

  10. Osteoid osteoma: radionuclide diagnosis

    SciTech Connect

    Helms, C.A.; Hattner, R.S.; Vogler, J.B.

    1984-06-01

    The double-density sign, seen on radionuclide bone scans, is described for diagnosing osteoid osteomas and for localizing the nidus. Its use in differentiating the nidus of an osteoid osteoma from osteomyelitis is also described. The utility of computed tomography in localization of the nidus is also illustrated. The double-density sign was helpful in diagnosing seven cases of surgically confirmed osteoid osteoma.

  11. The effect of ischemic preconditioning on the recovery of skeletal muscle following tourniquet ischemia.

    PubMed

    Whetzel, T P; Stevenson, T R; Sharman, R B; Carlsen, R C

    1997-12-01

    It has been well documented that ischemic preconditioning limits ischemic-reperfusion injury in cardiac muscle, but the ability of ischemic preconditioning to limit skeletal muscle injury is less clear. Previous reports have emphasized the beneficial effects of ischemic preconditioning on skeletal muscle structure and capillary perfusion but have not evaluated muscle function. We investigated the morphologic and functional consequences of ischemic preconditioning, followed by a 2-hour period of tourniquet ischemia on muscles in the rat hindlimb. The 2-hour ischemia was imposed without preconditioning, or was preceded by three brief (10 minutes on/10 minutes off) preischemic conditioning intervals. We compared muscle morphology, isometric contractile function, and muscle fatigue properties in predominantly fast-twitch, tibialis anterior muscles 3 (n = 8) and 7 (n = 8) days after ischemia-reperfusion. Two hours of ischemia, followed by reperfusion, results in a 20 percent reduction of muscle mass (p < 0.05) and a 33 percent reduction in tetanic tension (p < 0.05) when compared with controls (n = 8) at 3 days. The same protocol, when preceded by ischemic preconditioning, results in similar decreases in muscle mass and contractile function. Neuromuscular transmission was also impaired in both ischemic groups 7 days after ischemia. Nerve-evoked maximum tetanic tension was 69 percent of the tension produced by direct muscle stimulation in the ischemia group and 65 percent of direct tension in the ischemic preconditioning/ischemia group. In summary, ischemic preconditioning, using the same protocol reported to be effective in limiting infarct size in porcine muscle, had no significant benefit in limiting injury or improving recovery in the ischemic rat tibialis anterior. The value of ischemic preconditioning in reducing imposed ischemic-reperfusion-induced functional deficits in skeletal muscle remains to be demonstrated.

  12. EANM/ESC guidelines for radionuclide imaging of cardiac function.

    PubMed

    Hesse, B; Lindhardt, T B; Acampa, W; Anagnostopoulos, C; Ballinger, J; Bax, J J; Edenbrandt, L; Flotats, A; Germano, G; Stopar, T Gmeiner; Franken, P; Kelion, A; Kjaer, A; Le Guludec, D; Ljungberg, M; Maenhout, A F; Marcassa, C; Marving, J; McKiddie, F; Schaefer, W M; Stegger, L; Underwood, R

    2008-04-01

    Radionuclide imaging of cardiac function represents a number of well-validated techniques for accurate determination of right (RV) and left ventricular (LV) ejection fraction (EF) and LV volumes. These first European guidelines give recommendations for how and when to use first-pass and equilibrium radionuclide ventriculography, gated myocardial perfusion scintigraphy, gated PET, and studies with non-imaging devices for the evaluation of cardiac function. The items covered are presented in 11 sections: clinical indications, radiopharmaceuticals and dosimetry, study acquisition, RV EF, LV EF, LV volumes, LV regional function, LV diastolic function, reports and image display and reference values from the literature of RVEF, LVEF and LV volumes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "prevailing or general consensus". The guidelines are designed to assist in the practice of referral to, performance, interpretation and reporting of nuclear cardiology studies for the evaluation of cardiac performance.

  13. Use of susceptibility-weighted imaging in assessing ischemic penumbra

    PubMed Central

    Wu, Xiujuan; Luo, Song; Wang, Ying; Chen, Yang; Liu, Jun; Bai, Jing; Feng, Jiachun; Zhang, Hongliang

    2017-01-01

    Abstract Rationale: The ischemic penumbra assessment is essential for the subsequent therapy and prediction of evolution in patients with acute ischemic infraction. Although controversial as a perfect equivalence to penumbra, perfusion-weighted imaging (PWI)-diffusion-weighted imaging (DWI) mismatch may predict the response to thrombolysis. Due to the reliance of PWI on contrast agents, noninvasive alternatives remain an unmet need. Patient concerns: We reported a 65-year-old man complained of paroxysmal hemiplegia of his right limbs and anepia for 2 days, whereas the symptoms lasted for about 12 hours when he admitted to the hospital. Diagnosis: We diagnosed it as acute ischemic stroke caused by the left middle cerebral artery stenosis. Interventions: Susceptibility-weighted imaging (SWI), multimodal magnetic resonance imaging (MRI) work-up which includes conventional MRI sequences (T1WI, T2WI, and FLAIR), DWI, PWI. Outcomes: His DWI-SWI mismatch was comparable to that of DWI-PWI at admission, suggesting that DWI-SWI could predict ischemic penumbra in patient with acute infarction. He refused the digital subtraction angiography examination or stenting, and he was treated with aspirin, atorvastain, and supportive treatment. The patient received a reexamination of the conventional MRI and SWI 11 days later. Expansion of the infarction in the affected MCA territory resulted from the penumbra indicated by the mismatch between DWI-SWI. Lessons: SWI can be used as a noninvasive alternative to evaluate the ischemic penumbra. Besides, SWI can provide perfusion information comparable to PWI and SWI is sufficient to identify occlusive arteries. PMID:28178170

  14. The effect of nifedipine on myocardial perfusion and metabolism in systemic sclerosis. A positron emission tomographic study

    SciTech Connect

    Duboc, D.; Kahan, A.; Maziere, B.; Loc'h, C.; Crouzel, C.; Menkes, C.J.; Amor, B.; Strauch, G.; Guerin, F.; Syrota, A. )

    1991-02-01

    We assessed the effect of nifedipine on myocardial perfusion and metabolism in 9 patients with systemic sclerosis, using positron emission tomography with a perfusion tracer (potassium-38) and a metabolic tracer (18F-fluorodeoxyglucose (18FDG)). Nifedipine, 20 mg 3 times daily for 1 week, induced a significant increase in 38K myocardial uptake, a significant decrease in 18FDG myocardial uptake, and a significant increase in the myocardial 38K: 18FDG ratio. These results indicate that the increase in myocardial perfusion is associated with modifications in myocardial energy metabolism, which probably result from a beneficial anti-ischemic effect of nifedipine in patients with systemic sclerosis.

  15. Perfusion-diffusion mismatch: does it identify who will benefit from reperfusion therapy?

    PubMed

    Powers, William J

    2012-06-01

    A method to determine which patients would benefit from reperfusion therapies after 4.5 h would greatly add to our ability to reduce the disability caused by stroke. The goal of magnetic resonance perfusion-diffusion imaging in hyperacute ischemic stroke is to identify regions of the brain that will die if untreated and will live and regain function if quickly reperfused. The clinical value of perfusion-diffusion imaging in hyperacute ischemic stroke can be proven only by demonstrating empirically in a randomized controlled trial (RCT) that there is an improvement in patient outcome that depends on the use of the neuroimaging modality to guide therapy. To date, there have been only a few RCTs that have evaluated whether perfusion-diffusion imaging can identify a subgroup of patients with ischemic stroke more than 4.5 h from onset in whom the overall benefit from reperfusion therapy outweighs the risk. None have met the rigorous design requirements of the three-group study necessary to adequately test this hypothesis, and none have even met their own criteria for demonstrating a clinical benefit. While studies are not sufficient to conclusively disprove the hypothesis there are no RCT data to support it, and thus, the clinical value of MRI perfusion-diffusion imaging in this setting remains unproven. It is worthy of further investigation in rigorously designed RCTs. However, the risks of symptomatic intracerebral hemorrhage with reperfusion therapies in acute ischemic stroke are proven. Unless RCT data are forthcoming to demonstrate that MRI perfusion-diffusion mismatch improves clinical outcome, it should not be used to guide delayed reperfusion therapy.

  16. EBS Radionuclide Transport Abstraction

    SciTech Connect

    J.D. Schreiber

    2005-08-25

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in ''Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration'' (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment for the license application (TSPA-LA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA-LA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers

  17. How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

    PubMed Central

    Habertheuer, Andreas; Wiedemann, Dominik; Kocher, Alfred; Laufer, Guenther; Vallabhajosyula, Prashanth

    2015-01-01

    Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data. PMID:26713319

  18. Perfusion lung scan: an aid in detection of lymphangitic carcinomatosis

    SciTech Connect

    Bates, S.E.; Tranum, B.L.

    1982-07-15

    Lymphangitic carcinomatosis is usually a late manifestation of metastatic disease. The patient usually presents with cough or dyspnea, and the chest radiograph is often nondiagnostic. Two patients are presented who developed symptoms while on adjuvant chemotherapy. Both had abnormal perfusion lung scans. One had matching ventilation defects; the other a normal ventilation study. Biopsy revealed metastatic carcinoma; in one case tumor was seen in both the pulmonary lymphatics and arterioles; in the other, tumor was identified but the site could not be specified. The radionuclide lung scan is a technique which can speed diagnosis and institution of therapy in lymphangitic carcinomatosis.

  19. Simultaneous technetium-99m MIBI angiography and myocardial perfusion imaging

    SciTech Connect

    Baillet, G.Y.; Mena, I.G.; Kuperus, J.H.; Robertson, J.M.; French, W.J.

    1989-01-01

    Resting first-pass radionuclide angiography (FPRNA) was performed with the myocardial perfusion agent technetium-99m MIBI. In 27 patients, it was compared with technetium-99m diethylenetriamine pentaacetic acid FPRNA. A significant correlation was present in left (r = 0.93, p less than 0.001) as well as right (r = 0.92, p less than 0.001) ventricular ejection fraction measured with both radiopharmaceuticals. In 13 patients, MIBI derived segmental wall motion was compared with contrast ventriculography. A high correlation was present (p less than 0.001), and qualitative agreement was found in 38/52 segments. In 19 patients with myocardial infarction a significant correlation was present between MIBI segmental wall motion and perfusion scores (p less than 0.001). In ten patients with a history of myocardial infarction, 18 myocardial segments demonstrated diseased coronary vessels and impaired wall motion at contrast angiography. These segments were all identified by the MIBI wall motion and perfusion study. We conclude that MIBI is a promising agent for simultaneous evaluation of cardiac function and myocardial perfusion at rest.

  20. Targeted radionuclide therapy

    PubMed Central

    Williams, Lawrence E.; DeNardo, Gerald L.; Meredith, Ruby F.

    2008-01-01

    Targeted radionuclide therapy (TRT) seeks molecular and functional targets within patient tumor sites. A number of agents have been constructed and labeled with beta, alpha, and Auger emitters. Radionuclide carriers spanning a broad range of sizes; e.g., antibodies, liposomes, and constructs such as nanoparticles have been used in these studies. Uptake, in percent-injected dose per gram of malignant tissue, is used to evaluate the specificity of the targeting vehicle. Lymphoma (B-cell) has been the primary clinical application. Extension to solid tumors will require raising the macroscopic absorbed dose by several-fold over values found in present technology. Methods that may effect such changes include multistep targeting, simultaneous chemotherapy, and external sequestration of the agent. Toxicity has primarily involved red marrow so that marrow replacement can also be used to enhance future TRT treatments. Correlation of toxicities and treatment efficiency has been limited by relatively poor absorbed dose estimates partly because of using standard (phantom) organ sizes. These associations will be improved in the future by obtaining patient-specific organ size and activity data with hybrid SPECT∕CT and PET∕CT scanners. PMID:18697529

  1. Association between retinal hemorrhagic pattern and macular perfusion status in eyes with acute branch retinal vein occlusion

    PubMed Central

    Muraoka, Yuki; Uji, Akihito; Tsujikawa, Akitaka; Murakami, Tomoaki; Ooto, Sotaro; Suzuma, Kiyoshi; Takahashi, Ayako; Iida, Yuto; Miwa, Yuko; Hata, Masayuki; Yoshimura, Nagahisa

    2016-01-01

    This prospective study included 63 eyes with acute branch retinal vein occlusion (BRVO) to evaluate the retinal hemorrhagic patterns at the posterior poles and explore their clinical relevance in macular perfusion differentiation. Retinal hemorrhagic patterns and macular perfusion status were evaluated via fundus photography and fluorescein angiography, respectively. Macular perfusion was judged as nonischemic in 30, ischemic in 28, and undeterminable in 5 among the 63 eyes. Predominant hemorrhagic patterns were flame-shaped in 39 (67.2%) and non-flame-shaped in 19 (32.8%) eyes. All 39 eyes with a flame-shaped hemorrhage showed a nonischemic macula. Of the 19 eyes classified as having a non-flame-shaped hemorrhage, 13 (68.4%) had an ischemic macula and 6 (31.6%) had a nonischemic macula (P < 0.001). Parallelism in eyes with a flame-shaped hemorrhage was higher than in those with a non-flame-shaped hemorrhage (P < 0.001), and in those with a nonischemic macula versus those with an ischemic macula (P < 0.001). The area under the curve for parallelism was 0.975 (P < 0.001), suggesting an accurate diagnostic parameter for macular perfusion differentiation. In conclusion, we objectively evaluated retinal hemorrhagic patterns at the posterior pole in BRVO using the parallelism method, which was useful in differentiating macular perfusion status. PMID:27334338

  2. Quantitation of the critically ischemic zone at risk during acute coronary occlusion using PET

    SciTech Connect

    Merhige, M.; Garza, D.; Sease, D.; Rowe, R.W.; Tewson, T.; Emran, A.; Bolomey, L.; Gould, K.L. )

    1991-08-01

    Critical myocardial ischemia has been defined experimentally during acute coronary occlusion as flow reduction of 50% or more since cellular ATP depletion begins to occur beyond this flow reduction threshold, placing tissue at risk of cellular injury. To test the hypothesis that critically ischemic fractional left ventricular mass can be measured noninvasively with PET, nine dogs were imaged in a multi-slice positron camera using the perfusion tracer 13N-ammonia, while radiolabeled microspheres were injected into the left atrium during acute coronary occlusion. Images were processed using a 50% threshold and the size of the resulting perfusion defect was expressed as a fraction of total left ventricular image volume. The critically ischemic left ventricular fraction determined in vitro from the microsphere perfusion data, ranged from 5% to 30% of the total left ventricular weight and correlated closely with that determined noninvasively by PET with r = 0.94 (y = 1.05X - 2.0%). The authors conclude that the fraction of left ventricular myocardium rendered critically ischemic during acute coronary occlusion can be measured accurately and noninvasively in vivo using perfusion imaging with positron emission tomography.

  3. Reactor-Produced Medical Radionuclides

    SciTech Connect

    Mirzadeh, Saed; Mausner, Leonard; Garland, Marc A

    2011-01-01

    The therapeutic use of radionuclides in nuclear medicine, oncology and cardiology is the most rapidly growing use of medical radionuclides. Since most therapeutic radionuclides are neutron rich and decay by beta emission, they are reactor-produced. This chapter deals mainly with production approaches with neutrons. Neutron interactions with matter, neutron transmission and activation rates, and neutron spectra of nuclear reactors are discussed in some detail. Further, a short discussion of the neutron-energy dependence of cross sections, reaction rates in thermal reactors, cross section measurements and flux monitoring, and general equations governing the reactor production of radionuclides are presented. Finally, the chapter is concluded by providing a number of examples encompassing the various possible reaction routes for production of a number of medical radionuclides in a reactor.

  4. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  5. Ischemic optic neuropathy.

    PubMed

    Hayreh, Sohan Singh

    2009-01-01

    Ischemic optic neuropathy is one of the major causes of blindness or seriously impaired vision, yet there is disagreement as to its pathogenesis, clinical features and especially its management. This is because ischemic optic neuropathy is not one disease but a spectrum of several different types, each with its own etiology, pathogenesis, clinical features and management. They cannot be lumped together. Ischemic optic neuropathy is primarily of two types: anterior (AION) and posterior (PION), involving the optic nerve head (ONH) and the rest of the optic nerve respectively. Furthermore, both AION and PION have different subtypes. AION comprises arteritic (A-AION - due to giant cell arteritis) and, non-arteritic (NA-AION - due to causes other than giant cell arteritis); NA-AION can be further classified into classical NA-AION and incipient NA-AION. PION consists of arteritic (A-PION - due to giant cell arteritis), non-arteritic (NA-PION - due to causes other than giant cell arteritis), and surgical (a complication of several systemic surgical procedures). Thus, ischemic optic neuropathy consists of six distinct types of clinical entities. NA-AION is by far the most common type and one of the most prevalent and visually crippling diseases in the middle-aged and elderly. A-AION, though less common, is an ocular emergency and requires early diagnosis and immediate treatment with systemic high dose corticosteroids to prevent further visual loss, which is entirely preventable. Controversy exists regarding the pathogenesis, clinical features and especially management of the various types of ischemic optic neuropathy because there are multiple misconceptions about its many fundamental aspects. Recently emerging information on the various factors that influence the optic nerve circulation, and also the various systemic and local risk factors which play important roles in the development of various types of ischemic optic neuropathy have given us a better understanding of

  6. External carotid artery angioplasty and stenting to augment cerebral perfusion in the setting of subacute symptomatic ipsilateral internal carotid artery occlusion. Case report.

    PubMed

    Adel, Joseph G; Bendok, Bernard R; Hage, Ziad A; Naidech, Andrew M; Miller, Jeffery W; Batjer, H Hunt

    2007-12-01

    The authors performed external carotid artery (ECA) angioplasty and stenting in a 45-year-old man who had presented with right hemispheric crescendo ischemic symptoms stemming from acute right internal carotid artery occlusion (ICAO). This unique application of ECA angioplasty and stenting augmented cerebral perfusion and improved clinical symptoms. In certain situations, ECA stenting can increase cerebral perfusion in the setting of ICAO and ECA stenosis. The authors are the first to describe this approach in this context.

  7. Radionuclide therapy for arthritic knees

    SciTech Connect

    Doepel, L.K.

    1985-02-08

    A new radionuclide therapeutic approach for rheumatoid arthritis of the knee is described. This therapy combines a short-lived radionuclide with a carrier whose physical and chemical characteristics aid retention of the radioactive particles within the joint. Joining a radionuclide to a particulate carrier had not been explored previously as a potential method for inhibiting radiation leakage. The treatment couples the rare earth element dysprosium 165 to ferric hydroxide in macroaggregate form (size range: 3 to 10 ..mu..m). After the relatively inert iron complex penetrates the synovium, it causes cell death. Macrophages and phagocytes clear away the cellular debris, essentially eliminating the synovium.

  8. Harmonic analysis of perfusion pumps.

    PubMed

    Dougherty, F Carroll; Donovan, F M; Townsley, Mary I

    2003-12-01

    The controversy over the use of nonpulsatile versus pulsatile pumps for maintenance of normal organ function during ex vivo perfusion has continued for many years, but resolution has been limited by lack of a congruent mathematical definition of pulsatility. We hypothesized that the waveform frequency and amplitude, as well as the underlying mean distending pressure are all key parameters controlling vascular function. Using discrete Fourier Analysis, our data demonstrate the complexity of the pulmonary arterial pressure waveform in vivo and the failure of commonly available perfusion pumps to mimic in vivo dynamics. In addition, our data show that the key harmonic signatures are intrinsic to the perfusion pumps, are similar for flow and pressure waveforms, and are unchanged by characteristics of the downstream perfusion circuit or perfusate viscosity.

  9. Quantitative myocardial perfusion measurement using CT perfusion: a validation study in a porcine model of reperfused acute myocardial infarction.

    PubMed

    So, Aaron; Hsieh, Jiang; Li, Jian-Ying; Hadway, Jennifer; Kong, Hua-Fu; Lee, Ting-Yim

    2012-06-01

    We validated a CT perfusion technique with beam hardening (BH) correction for quantitative measurement of myocardial blood flow (MBF). Acute myocardial infarction (AMI) was created in four pigs by occluding the distal LAD for 1 h followed by reperfusion. MBF was measured from dynamic contrast enhanced CT (DCE-CT) scanning of the heart, with correction of cardiac motion and BH, before ischemic insult and on day 7, 10 and 14 post. On day 14 post, radiolabeled microspheres were injected to measure MBF and the results were compared with those measured by CT perfusion. Excised hearts were stained with 2,3,5-triphenyltetrazolium chloride (TTC) to determine the relationship between MBF measured by CT Perfusion and myocardial viability. MBF measured by CT perfusion was strongly correlated with that by microspheres over a wide range of MBF values (R = 0.81, from 25 to 225 ml min(-1) 100 g(-1)). While MBF in the LAD territory decreased significantly from 98.4 ± 2.5 ml min(-1) 100 g(-1) at baseline to 32.2 ± 9.1 ml min(-1) 100 g(-1), P < 0.05 at day 7 and to 49.4 ± 9.3 ml min(-1) 100 g(-1), P < 0.05 at day 14, the decrease in remote myocardium (LCx territory) from baseline (103.9 ± 1.9 ml min(-1) 100 g(-1)) was minimal throughout the study (90.6 ± 5.1 ml min(-1) 100 g(-1) on day 14 post, P > 0.05). TTC staining confirmed incomplete infarction in the LAD territory and no infarction in the LCx territory. Microvascular obstruction in infarcted tissue resulted in no-reflow and hence persistently low MBF in the reperfused LAD territory which contained a mixture of viable and non-viable tissue. CT perfusion measurement of MBF was accurate and correlated well with histology and microspheres measurements.

  10. DRESS and Ischemic Stroke.

    PubMed

    Cahyanur, Rahmat; Oktavia, Dina; Koesno, Sukamto

    2012-07-01

    DRESS (drug rash eosinophilia and systemic symptoms) is a life threatening condition characterized by skin rash, fever, leucocytosis with eosinophilia or atypical lymphocytosis, lymphadenopathy, and internal organ involvement. This case report would like to describe an interesting case of DRESS coincidence with ischemic stroke. A 38 year old woman had been admitted with skin rash and fever since four days before. Four weeks before admission she received antibiotic and multivitamin for one week. The patient looked ill, with body temperature 38.0°C. Marked physical findings were cervical lymphadenopathy and hepatomegaly. Dermatological examination finding was generalized exanthema. Laboratory evaluation showed leucocytosis, eosinophilia, and increased level of ALT and AST. During hospitalization the patient also suffered from ischemic stroke. Treatments administered in this patient were oxygen, adequate intravenous fluid, parenteral nutrition, methyl prednisolone, cethirizin bid, ranitidin bid, and antibiotic. The antibiotic treatment in this case was performed with graded challenge or test dosing.

  11. A practical approach to remote ischemic preconditioning and ischemic preconditioning against myocardial ischemia/reperfusion injury

    PubMed Central

    Totzeck, Matthias; Hendgen-Cotta, Ulrike B.; French, Brent A.; Rassaf, Tienush

    2016-01-01

    Although urgently needed in clinical practice, a cardioprotective therapeutic approach against myocardial ischemia/ reperfusion injury remains to be established. Remote ischemic preconditioning (rIPC) and ischemic preconditioning (IPC) represent promising tools comprising three entities: the generation of a protective signal, the transfer of the signal to the target organ, and the response to the transferred signal resulting in cardioprotection. However, in light of recent scientific advances, many controversies arise regarding the efficacy of the underlying signaling. We here show methods for the generation of the signaling cascade by rIPC as well as IPC in a mouse model for in vivo myocardial ischemia/ reperfusion injury using highly reproducible approaches. This is accomplished by taking advantage of easily applicable preconditioning strategies compatible with the clinical setting. We describe methods for using laser Doppler perfusion imaging to monitor the cessation and recovery of perfusion in real time. The effects of preconditioning on cardiac function can also be assessed using ultrasound or magnetic resonance imaging approaches. On a cellular level, we confirm how tissue injury can be monitored using histological assessment of infarct size in conjunction with immunohistochemistry to assess both aspects in a single specimen. Finally, we outline, how the rIPC-associated signaling can be transferred to the target cell via conservation of the signal in the humoral (blood) compartment. This compilation of experimental protocols including a conditioning regimen comparable to the clinical setting should proof useful to both beginners and experts in the field of myocardial infarction, supplying information for the detailed procedures as well as troubleshooting guides. PMID:28066791

  12. Intravascular Perfusion of Carbon Black Ink Allows Reliable Visualization of Cerebral Vessels

    PubMed Central

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

    2013-01-01

    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 dyes1 (i.e. carmine red, India ink) or latex with2 or without3 carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen3. Maeda et al.2 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 compound4. 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 manner5. 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 perfusion5. 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. PMID:23328838

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

    PubMed

    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.

  14. Radionuclide imaging of osteomyelitis.

    PubMed

    Palestro, Christopher J

    2015-01-01

    Radionuclide procedures frequently are performed as part of the diagnostic workup of osteomyelitis. Bone scintigraphy accurately diagnoses osteomyelitis in bones not affected by underlying conditions. Degenerative joint disease, fracture, and orthopedic hardware decrease the specificity of the bone scan, making it less useful in these situations. Gallium-67 scintigraphy was often used as an adjunct to bone scintigraphy for diagnosing osteomyelitis. However, now it is used primarily for spinal infections when (18)F-FDG imaging cannot be performed. Except for the spine, in vitro-labeled leukocyte imaging is the nuclear medicine test of choice for diagnosing complicating osteomyelitis. Leukocytes accumulate in bone marrow as well as in infection. Performing complementary bone marrow imaging with (99m)Tc-sulfur colloid facilitates the differentiation between osteomyelitis and normal marrow and improves test overall accuracy. Antigranulocyte antibodies and antibody fragments, such as (99m)Tc-besilesomab and (99m)Tc-sulesomab, were developed to eliminate the disadvantages associated with in vitro-labeled leukocytes. These agents, however, have their own shortcomings and are not widely available. As biotin is used as a growth factor by certain bacteria, (111)In-biotin is useful to diagnose spinal infections. Radiolabeled synthetic fragments of ubiquicidin, a naturally occurring human antimicrobial peptide that targets bacteria, can differentiate infection from sterile inflammation and may be useful to monitor response to treatment. (18)F-FDG is extremely useful in the diagnostic workup of osteomyelitis. Sensitivity in excess of 95% and specificity ranging from 75%-99% have been reported. (18)F-FDG is the radionuclide test of choice for spinal infection. The test is sensitive, with a high negative predictive value, and reliably differentiates degenerative from infectious vertebral body end-plate abnormalities. Data on the accuracy of (18)F-FDG for diagnosing diabetic pedal

  15. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  16. Drift-Scale Radionuclide Transport

    SciTech Connect

    J. Houseworth

    2004-09-22

    The purpose of this model report is to document the drift scale radionuclide transport model, taking into account the effects of emplacement drifts on flow and transport in the vicinity of the drift, which are not captured in the mountain-scale unsaturated zone (UZ) flow and transport models ''UZ Flow Models and Submodels'' (BSC 2004 [DIRS 169861]), ''Radionuclide Transport Models Under Ambient Conditions'' (BSC 2004 [DIRS 164500]), and ''Particle Tracking Model and Abstraction of Transport Process'' (BSC 2004 [DIRS 170041]). The drift scale radionuclide transport model is intended to be used as an alternative model for comparison with the engineered barrier system (EBS) radionuclide transport model ''EBS Radionuclide Transport Abstraction'' (BSC 2004 [DIRS 169868]). For that purpose, two alternative models have been developed for drift-scale radionuclide transport. One of the alternative models is a dual continuum flow and transport model called the drift shadow model. The effects of variations in the flow field and fracture-matrix interaction in the vicinity of a waste emplacement drift are investigated through sensitivity studies using the drift shadow model (Houseworth et al. 2003 [DIRS 164394]). In this model, the flow is significantly perturbed (reduced) beneath the waste emplacement drifts. However, comparisons of transport in this perturbed flow field with transport in an unperturbed flow field show similar results if the transport is initiated in the rock matrix. This has led to a second alternative model, called the fracture-matrix partitioning model, that focuses on the partitioning of radionuclide transport between the fractures and matrix upon exiting the waste emplacement drift. The fracture-matrix partitioning model computes the partitioning, between fractures and matrix, of diffusive radionuclide transport from the invert (for drifts without seepage) into the rock water. The invert is the structure constructed in a drift to provide the floor of the

  17. Ex vivo lung perfusion

    PubMed Central

    Machuca, Tiago N.

    2014-01-01

    Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs. PMID:25132972

  18. PERFUSION FOR MYOCARDIAL REVASCULARIZATION WITHOUT AN ARTIFICIAL OXYGENATOR (New Method to Reduce Surgical Morbidity)

    PubMed Central

    De Moraes, Domingos Junqueira; Abilio, Fued Michel; Cunha, Marcos; Feitosa, Lionicio A.; Aragão, Esmeraldino; Cysne, Eumenes; Vieira, Roberto; Glavam, Haroldo C. C.; Zaniolo, Waldomiro; Netto, Mario Salles; Villela, Ronaldo De A.; Labrunie, Pierre

    1979-01-01

    Thirteen patients were submitted to direct myocardial revascularization (saphenous vein graft) without the use of an artificial oxygenator. The perfusion was done by a left ventricle-to-aorta bypass and autogenous oxygenation. Most patients had three grafts implanted plus endarterectomy of the distal right coronary artery. There was one hospital death that was apparently not related to the method used. Perfusion time ranged from 45 minutes to 4 hours. Body temperature during perfusion was kept between 25 and 30° C. Perfusion flow was maintained between 25 to 50 ml per kg of body weight per minute. Ischemic, hypothermic cardiac arrest was employed. We demonstrated for the first time that perfusion for this kind of heart surgery could be done with no artificial oxygenators and, apparently, is safer for the patients. There were no bleeding problems even in perfusions as long as 4 hours. There was no respiratory dysfunction, and artificial respiration was used for only 6 to 12 hours. The patients awoke at the end of surgery with no signs or symptoms of central nervous system damage, and vasopressor drugs were rarely used after surgery. Although the experience is very small, it suggests that many postoperative problems, especially those related to bleeding and respiratory dysfunction may be reduced or eliminated by this new method. PMID:15216319

  19. Anthropogenic radionuclides in the environment

    SciTech Connect

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  20. Acute ischemic stroke update.

    PubMed

    Baldwin, Kathleen; Orr, Sean; Briand, Mary; Piazza, Carolyn; Veydt, Annita; McCoy, Stacey

    2010-05-01

    Stroke is the third most common cause of death in the United States and is the number one cause of long-term disability. Legislative mandates, largely the result of the American Heart Association, American Stroke Association, and Brain Attack Coalition working cooperatively, have resulted in nationwide standardization of care for patients who experience a stroke. Transport to a skilled facility that can provide optimal care, including immediate treatment to halt or reverse the damage caused by stroke, must occur swiftly. Admission to a certified stroke center is recommended for improving outcomes. Most strokes are ischemic in nature. Acute ischemic stroke is a heterogeneous group of vascular diseases, which makes targeted treatment challenging. To provide a thorough review of the literature since the 2007 acute ischemic stroke guidelines were developed, we performed a search of the MEDLINE database (January 1, 2004-July 1, 2009) for relevant English-language studies. Results (through July 1, 2009) from clinical trials included in the Internet Stroke Center registry were also accessed. Results from several pivotal studies have contributed to our knowledge of stroke. Additional data support the efficacy and safety of intravenous alteplase, the standard of care for acute ischemic stroke since 1995. Due to these study results, the American Stroke Association changed its recommendation to extend the time window for administration of intravenous alteplase from within 3 hours to 4.5 hours of symptom onset; this recommendation enables many more patients to receive the drug. Other findings included clinically useful biomarkers, the role of inflammation and infection, an expanded role for placement of intracranial stents, a reduced role for urgent carotid endarterectomy, alternative treatments for large-vessel disease, identification of nontraditional risk factors, including risk factors for women, and newly published pediatric stroke guidelines. In addition, new devices for

  1. Myocardial perfusion assessment with contrast echocardiography

    NASA Astrophysics Data System (ADS)

    Desco, Manuel; Ledesma-Carbayo, Maria J.; Santos, Andres; Garcia-Fernandez, Miguel A.; Marcos-Alberca, Pedro; Malpica, Norberto; Antoranz, Jose C.; Garcia-Barreno, Pedro

    2001-05-01

    Assessment of intramyocardial perfusion by contrast echocardiography is a promising new technique that allows to obtain quantitative parameters for the assessment of ischemic disease. In this work, a new methodology and a software prototype developed for this task are presented. It has been validated with Coherent Contrast Imaging (CCI) images acquired with an Acuson Sequoia scanner. Contrast (Optison microbubbles) is injected continuously during the scan. 150 images are acquired using low mechanical index U/S pulses. A burst of high mechanical index pulses is used to destroy bubbles, thus allowing to detect the contrast wash-in. The stud is performed in two conditions: rest and pharmacologically induced stress. The software developed allows to visualized the study (cine) and to select several ROIs within the heart wall. The position of these ROIs along the cardiac cycle is automatically corrected on the basis of the gradient field, and they can also be manually corrected in case the automatic procedure fails. Time curves are analyzed according to a parametric model that incorporates both contrast inflow rate and cyclic variations. Preliminary clinical results on 80 patients have allowed us to identify normal and pathological patterns and to establish the correlation of quantitative parameters with the real diagnosis.

  2. Cerebral-Body Perfusion Model

    DTIC Science & Technology

    1990-07-01

    compared to the 0.5g curve) fall in flow. Fig. 9b, showing the 5g case, strongly suggests a possible, so-called, " luxury perfusion ", in which natural...as the luxury perfusion situation which bypasses the flow with the nutrients it carries (through newly opened collaterals) and result in a "blackout...89-0054 CEREBRAL-BODY PERFUSION MODEL S. Sorek’, J. Bear2, and M., Feinsod3 in Collaboration with K. Allen4, L. Bunt5 and S. Ben-IHaiM6 July 1990

  3. Disruption of thrombospondin-2 accelerates ischemic fracture healing.

    PubMed

    Miedel, Emily; Dishowitz, Michael I; Myers, Marc H; Dopkin, Derek; Yu, Yan-Yiu; Miclau, Ted S; Marcucio, Ralph; Ahn, Jaimo; Hankenson, Kurt D

    2013-06-01

    Thrombospondin-2 (TSP2) is a matricellular protein that is highly up-regulated during fracture healing. TSP2 negatively regulates vascularity, vascular reperfusion following ischemia, and cutaneous wound healing. As well, TSP2-null mice show increased endocortical bone formation due to an enhanced number of mesenchymal progenitor cells and show increased cortical thickness. Mice deficient in TSP2 (TSP2-null) show an alteration in fracture healing, that is unrelated to their cortical bone phenotype, which is characterized by enhanced vascularization with a shift towards an intramembranous healing phenotype; thus, we hypothesized that there would be enhanced ischemic fracture healing in the absence of TSP2. We investigated whether an absence of TSP2 would enhance ischemic fracture healing utilizing Laser doppler, µCT and histological analysis. Ischemic tibial fractures were created in wildtype (WT) and TSP2-null mice and harvested 10, 20, or 40 days post-fracture. TSP2-null mice show enhanced vascular perfusion following ischemic fracture. At day 10 post-fracture, TSP2-null mice have 115% greater bone volume than WT mice. This is associated with a 122% increase in vessel density, 20% increase in cell proliferation, and 15% decrease in apoptosis compared to WT. At day 20, TSP2-null mice have 34% more bone volume, 51% greater bone volume fraction, and 37% more bone tissue mineral density than WT. By 40 days after fracture the TSP2-null mice have a 24% increase in bone volume fraction, but other parameters show no significant differences. These findings indicate TSP2 is a negative regulator of ischemic fracture healing and that in the absence of TSP2 bone regeneration is enhanced.

  4. Amelioration of myocardial ischemic reperfusion injury with Calendula officinalis.

    PubMed

    Ray, Diptarka; Mukherjee, Subhendu; Falchi, Mario; Bertelli, Aldo; Das, Dipak K

    2010-12-01

    Calendula officinalis of family Asteraceae, also known as marigold, has been widely used from time immemorial in Indian and Arabic cultures as an anti-inflammatory agent to treat minor skin wound and infections, burns, bee stings, sunburn and cancer. At a relatively high dose, calendula can lower blood pressure and cholesterol. Since inflammatory responses are behind many cardiac diseases, we sought to evaluate if calendula could be cardioprotective against ischemic heart disease Two groups of hearts were used: the treated rat hearts were perfused with calendula solution at 50 mM in KHB buffer (in mM: sodium chloride 118, potassium chloride 4.7, calcium chloride 1.7, sodium bicarbonate 25, potassium biphosphate 0.36, magnesium sulfate 1.2, and glucose 10) for 15 min prior to subjecting the heart to ischemia, while the control group was perfused with the buffer only. Calendula achieved cardioprotection by stimulating left ventricular developed pressure and aortic flow as well as by reducing myocardial infarct size and cardiomyocyte apoptosis. Cardioprotection appears to be achieved by changing ischemia reperfusion-mediated death signal into a survival signal by modulating antioxidant and anti-inflammatory pathways as evidenced by the activation of Akt and Bcl2 and depression of TNFα. The results further strengthen the concept of using natural products in degeneration diseases like ischemic heart disease.

  5. Luxury perfusion syndrome confirmed by sequential studies of regional cerebral blood flow and volume after extracranial to intracranial bypass surgery: case report.

    PubMed

    Higashi, S; Matsuda, H; Fujii, H; Ito, H; Yamashita, J

    1989-07-01

    We report a case of luxury perfusion syndrome with temporary neurological deterioration after extracranial to intracranial bypass surgery. A preoperative computed tomographic scan showed no detectable infarct, and the measurement of regional cerebral blood flow showed severe depression of ipsilateral hemispheric perfusion. The patient developed temporary neurological deterioration after bypass surgery, with no recognizable pathological signs on postoperative computed tomographic and angiographic studies. Regional cerebral blood flow and volume were more elevated during the period of neurological deterioration than after the subsequent recovery. This strongly suggests that excessive blood flow directed into chronically ischemic brain through a graft may induce a luxury perfusion syndrome resulting in neurological deterioration.

  6. Pulmonary ventilation/perfusion scan

    MedlinePlus

    ... JavaScript. A pulmonary ventilation/perfusion scan involves two nuclear scan tests to measure breathing (ventilation) and circulation ( ... In: Mettler FA, Guiberteau MJ, eds. Essentials of Nuclear Medicine Imaging . 6th ed. Philadelphia, PA: Elsevier Saunders; ...

  7. Effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart.

    PubMed

    Kansal, Sunil Kumar; Jyoti, Uma; Sharma, Samridhi; Kaura, Arun; Deshmukh, Rahul; Goyal, Sandeep

    2015-06-01

    Hyperlipidemia is regarded as independent risk factor in the development of ischemic heart disease, and it can increase the myocardial susceptibility to ischemia-/reperfusion (I/R)-induced injury. Hyperlipidemia attenuates the cardioprotective response of ischemic preconditioning (IPC). The present study investigated the effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat hearts. Hyperlipidemia was induced in rat by feeding high-fat diet (HFD) for 6 weeks then the serum lipid profile was observed. In experiment, the isolated Langendorff rat heart preparation was subjected to 4 cycles of ischemic preconditioning (IPC), then 30 min of ischemia followed by 120 min of reperfusion. Myocardial infarct size was elaborated morphologically by triphenyltetrazolium chloride (TTC) staining and biochemically by lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) release from coronary effluent and left ventricular collagen content. However, the effect of zinc supplement, i.e., zinc pyrithione (10 μM) perfused during reperfusion for 120 min, significantly abrogated the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart whereas administration of chelator of this zinc ionophore, i.e., N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene diamine (TPEN; 10 μM), perfused during reperfusion 2 min before the perfusion of zinc pyrithione abrogated the cardioprotective effect of zinc supplement during experiment in hyperlipidemic rat heart. Thus, the administration of zinc supplements limits the infarct size, LDH, and CK-MB and enhanced the collagen level which suggests that the attenuated cardioprotective effect of IPC in hyperlipidemic rat is due to zinc loss during reperfusion caused by ischemia/reperfusion.

  8. Multi-Center Prediction of Hemorrhagic Transformation in Acute Ischemic Stroke using Permeability Imaging Features

    PubMed Central

    Scalzo, Fabien; Alger, Jeffry R.; Hu, Xiao; Saver, Jeffrey L.; Dani, Krishna A.; Muir, Keith W.; Demchuk, Andrew M.; Coutts, Shelagh B.; Luby, Marie; Warach, Steven; Liebeskind, David S.

    2013-01-01

    Permeability images derived from magnetic resonance (MR) perfusion images are sensitive to blood-brain barrier derangement of the brain tissue and have been shown to correlate with subsequent development of hemorrhagic transformation (HT) in acute ischemic stroke. This paper presents a multi-center retrospective study that evaluates the predictive power in terms of HT of six permeability MRI measures including contrast slope (CS), final contrast (FC), maximum peak bolus concentration (MPB), peak bolus area (PB), relative recirculation (rR), and percentage recovery (%R). Dynamic T2*-weighted perfusion MR images were collected from 263 acute ischemic stroke patients from four medical centers. An essential aspect of this study is to exploit a classifier-based framework to automatically identify predictive patterns in the overall intensity distribution of the permeability maps. The model is based on normalized intensity histograms that are used as input features to the predictive model. Linear and nonlinear predictive models are evaluated using a crossvalidation to measure generalization power on new patients and a comparative analysis is provided for the different types of parameters. Results demonstrate that perfusion imaging in acute ischemic stroke can predict HT with an average accuracy of more than 85% using a predictive model based on a nonlinear regression model. Results also indicate that the permeability feature based on the percentage of recovery performs significantly better than the other features. This novel model may be used to refine treatment decisions in acute stroke. PMID:23587928

  9. Radionuclide injury to the lung.

    PubMed Central

    Dagle, G E; Sanders, C L

    1984-01-01

    Radionuclide injury to the lung has been studied in rats, hamsters, dogs, mice and baboons. Exposure of the lung to high dose levels of radionuclides produces a spectrum of progressively more severe functional and morphological changes, ranging from radiation pneumonitis and fibrosis to lung tumors. These changes are somewhat similar for different species. Their severity can be related to the absorbed radiation dose (measured in rads) produced by alpha, beta or gamma radiation emanating from various deposited radionuclides. The chemicophysical forms of radionuclides and spatial-temporal factors are also important variables. As with other forms of injury to the lung, repair attempts are highlighted by fibrosis and proliferation of pulmonary epithelium. Lung tumors are the principal late effect observed in experimental animals following pulmonary deposition of radionuclides at dose levels that do not result in early deaths from radiation pneumonitis or fibrosis. The predominant lung tumors described have been of epithelial origin and have been classified, in decreasing frequency of occurrence, as adenocarcinoma, bronchioloalveolar carcinoma, epidermoid carcinomas and combined epidermoid and adenocarcinoma. Mesothelioma and fibrosarcoma have been observed in rats, but less commonly in other species. Hemangiosarcomas were frequency observed in dogs exposed to beta-gamma emitters, and occasionally in rats exposed to alpha emitters. These morphologic changes in the lungs of experimental animals were reviewed and issues relevant to the prediction of human hazards discussed. PMID:6376095

  10. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  11. Radionuclide detection devices and associated methods

    DOEpatents

    Mann, Nicholas R.; Lister, Tedd E.; Tranter, Troy J.

    2011-03-08

    Radionuclide detection devices comprise a fluid cell comprising a flow channel for a fluid stream. A radionuclide collector is positioned within the flow channel and configured to concentrate one or more radionuclides from the fluid stream onto at least a portion of the radionuclide collector. A scintillator for generating scintillation pulses responsive to an occurrence of a decay event is positioned proximate at least a portion of the radionuclide collector and adjacent to a detection system for detecting the scintillation pulses. Methods of selectively detecting a radionuclide are also provided.

  12. CAD of myocardial perfusion

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

    Our purpose is in the automated evaluation of the physiological relevance of lesions in coronary angiograms. We aim to extract as much as possible quantitative information about the physiological condition of the heart from standard angiographic image sequences. Coronary angiography is still the gold standard for evaluating and diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. The dimensions of the stenosis can be assessed nowadays successfully with image processing based Quantitative Coronary Angiography (QCA) techniques. Our purpose is to assess the clinical relevance of the pertinent stenosis. We therefore analyze the myocardial perfusion as revealed in standard angiographic image sequences. In a Region-of-Interest (ROI) on the angiogram (without an overlaying major blood vessel) the contrast is measured as a function of time (the so-called time-density curve). The required hyperemic state of exercise is induced artificially by the injection of a vasodilator drug e.g. papaverine. In order to minimize motion artifacts we select based on the recorded ECG signal end-diastolic images in both a basal and a hyperemic run in the same projection to position the ROI. We present the development of the algorithms together with results of a small study of 20 patients which have been catheterized following the standard protocol.

  13. New objective criterion for determining, noninvasively, the healing potential of an ischemic ulcer

    SciTech Connect

    Siegel, M.E.; Stewart, C.A.; Wagner, W.; Sakimura, I.

    1981-02-01

    Peripheral vascular perfusion studies using intravenously administered thallium-201 were performed on 13 patients suffering from ischemic ulcer of the lower extermities. Scintillation camera views and point counting over the lesion and adjacent region were utilized to define qualitatively and quantitatively the relative hyperemia of the lesion. The preliminary findings demonstrate that when the relative hyperemia was equal to or greater than 1.5, 100% (seven of seven) went on to heal their ulcer with conservative management. Of those without this degree of hyperemia, 83% (five of six) will require amputation. Based on this limited series, noninvasive assessment of the relative hyperemia of an ischemic ulcer using thallium-201 is a new, useful, and objective indicator of the healing potential of a so-called ischemic ulcer.

  14. Ischemic mitral valve prolapse

    PubMed Central

    Cristiano, Spadaccio; Nenna, Antonio; Chello, Massimo

    2016-01-01

    Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient’s outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment. PMID:28149574

  15. Radionuclides in Chesapeake Bay sediments

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    Natural and manmade gamma-ray emitting radionuclides were measured in Chesapeake Bay sediments taken near the Calvert Cliffs Nuclear Power Plant site. Samples represented several water depths, at six locations, for five dates encompassing a complete seasonal cycle. Radionuclide contents of dry sediments ranged as follows: Tl-208, 40 to 400 pCi/kg; Bi-214, 200 to 800 pCi/kg; K, 0.04 to 2.1 percent; Cs-137 5 to 1900 pCi/kg; Ru106, 40 to 1000 pCikg Co60, 1 to 27 pCi/kg. In general, radionuclide contents were positively correlated with each other and negatively correlated with sediment grain size.

  16. 100 years of radionuclide metrology.

    PubMed

    Judge, S M; Arnold, D; Chauvenet, B; Collé, R; De Felice, P; García-Toraño, E; Wätjen, U

    2014-05-01

    The discipline of radionuclide metrology at national standards institutes started in 1913 with the certification by Curie, Rutherford and Meyer of the first primary standards of radium. In early years, radium was a valuable commodity and the aim of the standards was largely to facilitate trade. The focus later changed to providing standards for the new wide range of radionuclides, so that radioactivity could be used for healthcare and industrial applications while minimising the risk to patients, workers and the environment. National measurement institutes responded to the changing demands by developing new techniques for realising primary standards of radioactivity. Looking ahead, there are likely to be demands for standards for new radionuclides used in nuclear medicine, an expansion of the scope of the field into quantitative imaging to facilitate accurate patient dosimetry for nuclear medicine, and an increasing need for accurate standards for radioactive waste management and nuclear forensics.

  17. Advanced imaging to extend the therapeutic time window of acute ischemic stroke.

    PubMed

    Fisher, Marc; Albers, Gregory W

    2013-01-01

    Reperfusion therapy for acute stroke has evolved from the initial use of intravenous tissue plasminogen activator (tPA) within 3 hours of symptom onset to more recent guideline-recommended use up to 4.5 hours. In addition, endovascular therapy is increasingly utilized for stroke treatment and is typically initiated up to 8 hours after onset. Recent studies demonstrate that imaging of the ischemic penumbra with diffusion/perfusion magnetic resonance imaging (MRI) can identify subgroups of patients who are likely to improve following successful reperfusion (Target Mismatch profile) and others who are at increased risk for hemorrhage and poor clinical outcomes (Malignant profile). New data indicate that stent retriever devices provide better recanalization efficacy and clinical outcomes than the previously available mechanical thrombectomy devices. Going forward, we believe that the use of penumbral imaging with validated MRI techniques, as well as the currently less well-validated computed tomography (CT) perfusion approach, will maximize benefit and reduce the risk of adverse events and poor outcomes when used both early after stroke onset and at later time points. New trials that feature diffusion/perfusion MRI or CT perfusion-based patient selection for treatment with intravenous tPA and or endovascular therapies versus nonreperfused control groups are planned or in progress. We predict that these trials will confirm the hypothesis that penumbral imaging can enhance patient selection and extend the therapeutic time window for acute ischemic stroke.

  18. Impedance spectroscopy for monitoring ischemic injury in the intestinal mucosa.

    PubMed

    González, César A; Villanueva, Cleva; Othman, Salah; Narváez, Raúl; Sacristán, Emilio

    2003-05-01

    This work evaluates the feasibility of monitoring ischemic injury in the gastrointestinal mucosa by impedance spectroscopy, using a minimally invasive intestinal catheter. The disruption of the intestinal mucosa plays a key role in the evolution of shock and is the 'motor of multiple organ failure'. Different technologies have been developed to monitor mucosal perfusion, oxygenation and/or ischemia, but no practical method exists to assess tissue damage, which may be crucial for preventing multiple organ failure. The experimental protocol of this study relied on an isobaric model of hypovolemic shock in 16 anaesthetized rabbits assigned to three groups: sham (n = 6), ischemia (n = 5) and ischemia + reperfusion (n = 5). Complex impedance spectra were recorded in the range of 0.05 to 300 kHz, with simultaneous measurements of tonometric pHi in the ileum every 30 min for 4 h. Impedance spectra were reproducible, and those of tissue under prolonged ischemia were clearly differentiable from those of normally perfused tissue. The dynamic changes in impedance did not correlate directly with either tissue perfusion or pHi, but instead correlated well with the duration of ischemia. It is concluded that impedance spectroscopy does indeed measure changes in tissue injury, and could be a very useful tool to guide therapy of patients in shock.

  19. Simultaneous Individually Controlled Upper and Lower Body Perfusion for Valve-Sparing Root and Total Aortic Arch Replacement: A Case Study

    PubMed Central

    Fernandes, Philip; Mayer, Rick; Adams, Corey; Chu, Michael W.A.

    2011-01-01

    Abstract: Optimal perfusion strategies for extensive aortic resection in patients with mega-aortic syndromes include: tailored myocardial preservation, antegrade cerebral perfusion, controlled hypothermia and selective organ perfusion. Typically, the aortic arch resection and elephant trunk procedure are performed under hypothermic circulatory arrest with myocardial and cerebral protection. However, mesenteric and systemic ischemia occur during circulatory arrest and commonly rely upon deep hypothermia alone for metabolic protection. We hypothesized that simultaneously controlled mesenteric and systemic perfusion can attenuate some of the metabolic debt accrued during circulatory arrest, which may help improve perioperative outcomes. The perfusion strategy consisted of delivering a 1 to 3 liter per minute flow at 25°C to the head/upper body via right axillary graft and simultaneous perfusion to the lower body/mesenteric organs of 1 to 3 liters per minute at 30°C via a right femoral arterial graft. We describe our technique of simultaneous mesenteric, systemic, cerebral and myocardial perfusion, and protection utilized for a young male patient with Marfan’s syndrome, while undergoing a valve sparing root replacement, total arch replacement and elephant trunk reconstruction. This perfusion technique allowed us to deliver differential flow rates and temperatures to the upper and lower body (cold head/warm lower body perfusion) to minimize ischemic debt and quickly reverse metabolic derangements. PMID:22416605

  20. Radionuclide Imaging of Cardiovascular Infection.

    PubMed

    Ahmed, Fozia Zahir; James, Jackie; Memmott, Matthew J; Arumugam, Parthiban

    2016-02-01

    Owing to expanding clinical indications, cardiac implantable electronic devices (CIEDs) are being increasingly used. Despite improved surgical techniques and the use of prophylactic antimicrobial therapy, the rate of CIED-related infection is also increasing. Infection is a potentially serious complication, with clinical manifestations ranging from surgical site infection and local symptoms in the region of the generator pocket to fulminant endocarditis. The utility of radionuclide imaging as a stand-alone noninvasive diagnostic imaging test in patients with suspected endocarditis has been less frequently examined. This article summarizes the recent advances in radionuclide imaging for evaluation of patients with suspected cardiovascular infections.

  1. Radionuclide labeled lymphocytes for therapeutic use

    DOEpatents

    Srivastava, Suresh C.; Fawwaz, Rashid A.; Richards, Powell

    1985-01-01

    Lymphocytes labelled with .beta.-emitting radionuclides are therapeutically useful, particularly for lymphoid ablation. They are prepared by incubation of the lymphocytes with the selected radionuclide-oxine complex.

  2. Conditions and processes affecting radionuclide transport

    USGS Publications Warehouse

    Simmons, Ardyth M.; Neymark, Leonid A.

    2012-01-01

    Understanding of unsaturated-zone transport is based on laboratory and field-scale experiments. Fractures provide advective transport pathways. Sorption and matrix diffusion may contribute to retardation of radionuclides. Conversely, sorption onto mobile colloids may enhance radionuclide transport.

  3. Radionuclide labeled lymphocytes for therapeutic use

    DOEpatents

    Srivastava, S.C.; Fawwaz, R.A.; Richards, P.

    1983-05-03

    Lymphocytes labelled with ..beta..-emitting radionuclides are therapeutically useful, particularly for lymphoid ablation. They are prepared by incubation of the lymphocytes with the selected radionuclide-oxine complex.

  4. Radionuclide Sensors for Subsurface Water Monitoring

    SciTech Connect

    Timothy DeVol

    2006-06-30

    Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

  5. Measurement of radionuclides in waste packages

    DOEpatents

    Brodzinski, Ronald L.; Perkins, Richard W.; Rieck, Henry G.; Wogman, Ned A.

    1986-01-01

    A method is described for non-destructively assaying the radionuclide content of solid waste in a sealed container by analysis of the waste's gamma-ray spectrum and neutron emissions. Some radionuclides are measured by characteristic photopeaks in the gamma-ray spectrum; transuranic nuclides are measured by neutron emission rate; other radionuclides are measured by correlation with those already measured.

  6. [Role of Radionuclide Technologies in Medicine].

    PubMed

    Chernyaev, A P; Belousov, A V; Varzar, S M; Borchegovskaya, P Y; Nikolaeva, A A; Krusanov, G A

    2016-01-01

    The paper describes the role of radionuclide technologies among the nuclear-physical methods used in medicine. The condition and prospects of the development of nuclear technology with use of radionuclides in medicine, and in particular, the method of brachytherapy are analyzed. The analysis of the current state of applying radionuclide facilities in medicine is provided.

  7. TECHNOLOGIES FOR RADON AND RADIONUCLIDE REMOVAL

    EPA Science Inventory

    This paper provides a summary of the technologies that are currently being used to remove radionuclides from drinking water. The radionuclides that are featured are the radionuclides currently regulated by EPA; radium, radon and uranium. Tehnologies effective for removal of eac...

  8. Measurement of radionuclides in waste packages

    DOEpatents

    Brodzinski, R.L.; Perkins, R.W.; Rieck, H.G.; Wogman, N.A.

    1984-09-12

    A method is described for non-destructively assaying the radionuclide content of solid waste in a sealed container by analysis of the waste's gamma-ray spectrum and neutron emissions. Some radionuclides are measured by characteristic photopeaks in the gamma-ray spectrum; transuranic nuclides are measured by neutron emission rate; other radionuclides are measured by correlation with those already measured.

  9. [Cerebrolysin for acute ischemic stroke].

    PubMed

    iganshina, L E; Abakumova, T R

    2013-01-01

    The review discusses existing evidence of benefits and risks of cerebrolysin--a mixture of low-molecular-weight peptides and amino acids derived from pigs' brain tissue with proposed neuroprotective and neurotrophic properties, for acute ischemic stroke. The review presents results of systematic search and analysis of randomised clinical trials comparing cerebrolysin with placebo in patients with acute ischemic stroke. Only one trial was selected as meeting quality criteria. No difference in death and adverse events between cerebrolysin and placebo was established. The authors conclude about insufficiency of evidence to evaluate the effect of cerebrolysin on survival and dependency in people with acute ischemic stroke.

  10. Radionuclide evaluation in childhood injuries

    SciTech Connect

    Sty, J.R.; Starshak, R.J.; Hubbard, A.M.

    1983-07-01

    Radionuclide techniques serve an important role in evaluating childhood injuries. Frequently, they can be employed as the initial and definitive examination. At times they represent the only modality that will detect specific injuries such as the skeletal system. Familiarity with the advantages and limitations of tracer techniques will insure appropriate management of childhood injuries.

  11. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  12. Tumor Immunotargeting Using Innovative Radionuclides

    PubMed Central

    Kraeber-Bodéré, Françoise; Rousseau, Caroline; Bodet-Milin, Caroline; Mathieu, Cédric; Guérard, François; Frampas, Eric; Carlier, Thomas; Chouin, Nicolas; Haddad, Ferid; Chatal, Jean-François; Faivre-Chauvet, Alain; Chérel, Michel; Barbet, Jacques

    2015-01-01

    This paper reviews some aspects and recent developments in the use of antibodies to target radionuclides for tumor imaging and therapy. While radiolabeled antibodies have been considered for many years in this context, only a few have reached the level of routine clinical use. However, alternative radionuclides, with more appropriate physical properties, such as lutetium-177 or copper-67, as well as alpha-emitting radionuclides, including astatine-211, bismuth-213, actinium-225, and others are currently reviving hopes in cancer treatments, both in hematological diseases and solid tumors. At the same time, PET imaging, with short-lived radionuclides, such as gallium-68, fluorine-18 or copper-64, or long half-life ones, particularly iodine-124 and zirconium-89 now offers new perspectives in immuno-specific phenotype tumor imaging. New antibody analogues and pretargeting strategies have also considerably improved the performances of tumor immunotargeting and completely renewed the interest in these approaches for imaging and therapy by providing theranostics, companion diagnostics and news tools to make personalized medicine a reality. PMID:25679452

  13. CAD system for automatic analysis of CT perfusion maps

    NASA Astrophysics Data System (ADS)

    Hachaj, T.; Ogiela, M. R.

    2011-03-01

    In this article, authors present novel algorithms developed for the computer-assisted diagnosis (CAD) system for analysis of dynamic brain perfusion, computer tomography (CT) maps, cerebral blood flow (CBF), and cerebral blood volume (CBV). Those methods perform both quantitative analysis [detection and measurement and description with brain anatomy atlas (AA) of potential asymmetries/lesions] and qualitative analysis (semantic interpretation of visualized symptoms). The semantic interpretation (decision about type of lesion: ischemic/hemorrhagic, is the brain tissue at risk of infraction or not) of visualized symptoms is done by, so-called, cognitive inference processes allowing for reasoning on character of pathological regions based on specialist image knowledge. The whole system is implemented in.NET platform (C# programming language) and can be used on any standard PC computer with.NET framework installed.

  14. Modeling Radionuclide Transport in Clays

    SciTech Connect

    Zheng, Liange; Li, Lianchong; Rutqvist, Jonny; Liu, Hui -Hai; Birkholzer, Jens

    2012-05-01

    Clay/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated or plastic clays (Tsang and Hudson, 2010). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. During the lifespan of a clay repository, the repository performance is affected by complex thermal, hydrogeological, mechanical, chemical (THMC) processes, such as heat release due to radionuclide decay, multiphase flow, formation of damage zones, radionuclide transport, waste dissolution, and chemical reactions. All these processes are related to each other. An in-depth understanding of these coupled processes is critical for the performance assessment (PA) of the repository. These coupled processes may affect radionuclide transport by changing transport paths (e.g., formation and evolution of excavation damaged zone (EDZ)) and altering flow, mineral, and mechanical properties that are related to radionuclide transport. While radionuclide transport in clay formation has been studied using laboratory tests (e,g, Appelo et al. 2010, Garcia-Gutierrez et al., 2008, Maes et al., 2008), short-term field

  15. Cardioprotective effects of grape seed proanthocyanidin against ischemic reperfusion injury.

    PubMed

    Sato, M; Maulik, G; Ray, P S; Bagchi, D; Das, D K

    1999-06-01

    There is increasing evidence to indicate cardioprotective effects of red wine consumption. Such cardioprotective properties of wine have been attributed to certain polyphenolic constituents of grapes. The purpose of this investigation was to examine whether proanthocyanidins derived from grape seeds possess cardioprotective properties. Rats were randomly divided into two groups: grape-seed proanthocyanidin was administered orally to one group of rats (100 mg/kg/day) for 3 weeks while the other group served as control. After 3 weeks, rats were killed, hearts excised, mounted on the perfusion apparatus and perfused with Krebs-Henseleit bicarbonate (KHB) buffer. After stabilization hearts were perfused in the working mode for baseline measurements of contractile functions. Hearts were then subjected to 30 min of global ischemia followed by 2 h of reperfusion. Coronary perfusates were collected to monitor malonaldehyde formation, a presumptive marker for oxidative stress development. At the end of each experiment, the heart was processed for infarct size determination. Peroxyl radical scavenging activity of proanthocyanidin was determined by examining its ability to remove peroxyl radical generated by 2,2'-azobis (2-amidinopropane) dihydrochloride while hydroxyl radical scavenging activity was tested with its ability to reduce 7-OH.-coumarin-3-carboxylic acid. The results of our study demonstrated that proanthocyanidin-fed animals were resistant to myocardial ischemia reperfusion injury as evidenced by improved recovery of post-ischemic contractile functions. The proanthocyanidin-fed group revealed reduced extent of myocardial infarction compared to the control group. Fluorimetric study demonstrated the antioxidant property of proanthocyanidin as judged by its ability to directly scavenge peroxyl radicals. Taken together, the results of this study showed that grape seed-proanthocyanidins possess a cardioprotective effect against ischemia reperfusion injury. Such

  16. Preterm Hypoxic–Ischemic Encephalopathy

    PubMed Central

    Gopagondanahalli, Krishna Revanna; Li, Jingang; Fahey, Michael C.; Hunt, Rod W.; Jenkin, Graham; Miller, Suzanne L.; Malhotra, Atul

    2016-01-01

    Hypoxic–ischemic encephalopathy (HIE) is a recognizable and defined clinical syndrome in term infants that results from a severe or prolonged hypoxic–ischemic episode before or during birth. However, in the preterm infant, defining hypoxic–ischemic injury (HII), its clinical course, monitoring, and outcomes remains complex. Few studies examine preterm HIE, and these are heterogeneous, with variable inclusion criteria and outcomes reported. We examine the available evidence that implies that the incidence of hypoxic–ischemic insult in preterm infants is probably higher than recognized and follows a more complex clinical course, with higher rates of adverse neurological outcomes, compared to term infants. This review aims to elucidate the causes and consequences of preterm hypoxia–ischemia, the subsequent clinical encephalopathy syndrome, diagnostic tools, and outcomes. Finally, we suggest a uniform definition for preterm HIE that may help in identifying infants most at risk of adverse outcomes and amenable to neuroprotective therapies. PMID:27812521

  17. Ischemic ulcers - self-care

    MedlinePlus

    ... that can cause ischemic wounds include: Diseases that cause inflammation, such as lupus High blood pressure High cholesterol levels Chronic kidney disease Blockage of the lymph vessels , which causes fluid ...

  18. Viable neurons with luxury perfusion in hydrocephalus.

    PubMed

    Wong, C Y; Luciano, M G; MacIntyre, W J; Brunken, R C; Hahn, J F; Go, R T

    1997-09-01

    A woman with hydrocephalus due to aqueductal stenosis had functional imaging of cerebral perfusion and metabolism to demonstrate the effects of endoscopic third ventriculostomy--a new form of internal surgical shunting. Technetium-99m-ECD SPECT and 18F-FDG PET showed regional luxury perfusion at the left frontal region. Three months after a successful third ventriculostomy, a repeated imaging of cerebral perfusion and metabolism showed resolution of luxury perfusion and global improvement of both perfusion and metabolism. This concurred with postoperative clinical improvement. The paired imaging of cerebral perfusion and metabolism provides more information than just imaging perfusion or metabolism. Thus, the detection of perfusion and metabolism mismatch may open a new window of opportunity for surgical intervention.

  19. Identification of CSF fistulas by radionuclide counting

    SciTech Connect

    Yamamoto, Y.; Kunishio, K.; Sunami, N.; Yamamoto, Y.; Satoh, T.; Suga, M.; Asari, S. )

    1990-07-01

    A radionuclide counting method, performed with the patient prone and the neck flexed, was used successfully to diagnose CSF rhinorrhea in two patients. A normal radionuclide ratio (radionuclide counts in pledget/radionuclide counts in 1-ml blood sample) was obtained in 11 normal control subjects. Significance was determined to be a ratio greater than 0.37. Use of radionuclide counting method of determining CSF rhinorrhea is recommended when other methods have failed to locate a site of leakage or when posttraumatic meningitis suggests subclinical CSF rhinorrhea.

  20. 3D imaging of myocardial perfusion and coronary tree morphology from a single rotational angiogram

    NASA Astrophysics Data System (ADS)

    Lauritsch, Günter; Rohkohl, Christopher; Hornegger, Joachim; Sinha, Anil-Martin; Brachmann, Johannes; Rieber, Johannes; Rittger, Harald

    2011-03-01

    Diagnosis and treatment of coronary heart disease are performed in the catheter laboratory using an angiographic X-ray C-arm system. The morphology of the coronary tree and potentially ischemic lesions are determined in 2D projection views. The hemodynamic impact of the lesion would be valuable information for treatment decision. Using other modalities for functional imaging is disrupting the clinical workflow since the patient has to be transferred from the catheter laboratory to another scanner, and back to the catheter laboratory for performing the treatment. In this work a novel technology is used for simultaneous 3D imaging of first pass perfusion and the morphology of the coronary tree from a single rotational angiogram. A selective, single shot of contrast agent of less than 20ml directly into the coronaries is sufficient for a proper contrast resolution. Due to the long acquisition time cardiac motion has to be considered. A novel reconstruction technique for estimation and compensation of cardiac motion from the acquired projection data is used. The overlay of the 3D structure of the coronary tree and the perfusion image shows the correlation of myocardial areas and the associated coronary sections supporting that region. In a case example scar lesions caused by a former myocardial infarct are investigated. A first pass perfusion defect is found which is validated by a late enhancement magnetic resonance image. No ischemic defects are found. The non vital regions are still supported by the coronary vasculature.

  1. Isolation and Flow Cytometric Analysis of Immune Cells from the Ischemic Mouse Brain

    PubMed Central

    Boltze, Johannes; Wagner, Daniel-Christoph; Weise, Gesa

    2016-01-01

    Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident cells. A key mechanism of this inflammatory response is the migration of circulating immune cells to the ischemic brain facilitated by chemokine release and increased endothelial adhesion molecule expression. Brain-invading leukocytes are well-known contributing to early-stage secondary ischemic injury, but their significance for the termination of inflammation and later brain repair has only recently been noticed. Here, a simple protocol for the efficient isolation of immune cells from the ischemic mouse brain is provided. After transcardial perfusion, brain hemispheres are dissected and mechanically dissociated. Enzymatic digestion with Liberase is followed by density gradient (such as Percoll) centrifugation to remove myelin and cell debris. One major advantage of this protocol is the single-layer density gradient procedure which does not require time-consuming preparation of gradients and can be reliably performed. The approach yields highly reproducible cell counts per brain hemisphere and allows for measuring several flow cytometry panels in one biological replicate. Phenotypic characterization and quantification of brain-invading leukocytes after experimental stroke may contribute to a better understanding of their multifaceted roles in ischemic injury and repair. PMID:26967380

  2. Perfusion decellularization of whole organs.

    PubMed

    Guyette, Jacques P; Gilpin, Sarah E; Charest, Jonathan M; Tapias, Luis F; Ren, Xi; Ott, Harald C

    2014-01-01

    The native extracellular matrix (ECM) outlines the architecture of organs and tissues. It provides a unique niche of composition and form, which serves as a foundational scaffold that supports organ-specific cell types and enables normal organ function. Here we describe a standard process for pressure-controlled perfusion decellularization of whole organs for generating acellular 3D scaffolds with preserved ECM protein content, architecture and perfusable vascular conduits. By applying antegrade perfusion of detergents and subsequent washes to arterial vasculature at low physiological pressures, successful decellularization of complex organs (i.e., hearts, lungs and kidneys) can be performed. By using appropriate modifications, pressure-controlled perfusion decellularization can be achieved in small-animal experimental models (rat organs, 4-5 d) and scaled to clinically relevant models (porcine and human organs, 12-14 d). Combining the unique structural and biochemical properties of native acellular scaffolds with subsequent recellularization techniques offers a novel platform for organ engineering and regeneration, for experimentation ex vivo and potential clinical application in vivo.

  3. Effects of physical training on myocardial vascularity and perfusion.

    PubMed

    Scheuer, J

    1982-09-01

    Physical training is thought to be a stimulus for coronary vascular growth and coronary collateral development. This report is a summary of knowledge in the area. Studies in experimental animals with normal hearts indicate that physical training promotes increased myocardial capillary density and also causes enlargement of the surface coronary vessels. The physiologic effect of these changes on coronary vascular reserve and protection of segments of the heart against myocardial ischemia has not been established. Physically trained dogs and pigs do not appear to be protected against the effects of coronary occlusion, in that the ischemic area appears to be as large in trained animals as in untrained animals for any given coronary lesion. One study in physically trained rats appears to show protection against myocardial infarction, but whether this is related to coronary vascular changes has not been established. Experiments in dogs subjected to chronic narrowing or gradual occlusion demonstrate that physical training in these models does promote collateral blood flow as measured by retrograde flow in open-chest experiments. Studies using the microsphere technique in closed-chest animals confirms increased collateral flow to ischemic areas in some animals, but the magnitude of the increases appears to be small and varies greatly from animal to animal. Studies in athletes suggest that myocardial blood flow is lower at any submaximal level of training in athletes than in sedentary persons. Studies in patients with coronary artery disease have generally failed to show an increase in coronary blood flow or in perfusion of ischemic areas after physical training programs, but the techniques used might not have been sensitive enough to detect changes. The evidence in the experimental animals is sufficiently promising to indicate that the search should be continued to define physical training programs that will most stimulate myocardial vascularity and coronary collaterals

  4. Radionuclide synovectomy - essentials for rheumatologists.

    PubMed

    Chojnowski, Marek M; Felis-Giemza, Anna; Kobylecka, Małgorzata

    2016-01-01

    Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70-80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.

  5. Chernobyl radionuclide distribution and migration.

    PubMed

    Izrael, Yury A

    2007-11-01

    The accident at Unit No. 4 of the Chernobyl Nuclear Power Plant on 26 April 1986 presented severe challenges in radiation protection. Early activity measurements defined the contaminated areas in order to determine what persons should be evacuated on the basis of the exposure limit at that time of 100 mSv (10 rem) for accidents. The immediate definition of these areas was accomplished with specially equipped aircraft capable of measuring external gamma-exposure rate and radionuclide spectra. Over time, maps of 137Cs contamination (the most important long-lived radionuclide) have become more and more sophisticated and have been used for further determinations of the control of the consequences of the accident. About 70% of the total release of 137Cs was deposited in Belarus, the Russian Federation, and Ukraine; but there was also widespread deposition throughout the countries of Western Europe. Two atlases of contamination throughout Europe were prepared, and the Russian atlas included data on other radionuclides and on external gamma-exposure rates. The radiocesiums behaved as volatile radionuclides because of the volatility of cesium. In contrast to the typical pattern after nuclear weapons tests, 90Sr behaved only as a refractory element, as its volatile precursors krypton and rubidium had already decayed within the reactor. Nearly all of the refractory elements (strontium, plutonium, etc.) released by the accident were confined to the 30-km zone around the reactor. A proposal is made to develop a more complete atlas of 137Cs deposition from the accident that would include the entire Northern Hemisphere. Water was not an important vector of exposure to human beings following the accident.

  6. Natural chelates for radionuclide decorporation

    DOEpatents

    Premuzic, E.T.

    1983-08-25

    This invention relates to the method and resulting chelates of desorbing a radionuclide selected from thorium, uranium, and plutonium containing cultures in a bioavailable form involving pseudomonas or other microorganisms. A preferred microorganism is Pseudomonas aeruginosa which forms multiple chelates with thorium in the range of molecular weight 1000 to 1000 and also forms chelates with uranium of molecular weight in the area of 100 to 1000 and 1000 to 2000.

  7. Noise characteristics of CT perfusion imaging: how does noise propagate from source images to final perfusion maps?

    NASA Astrophysics Data System (ADS)

    Li, Ke; Chen, Guang-Hong

    2016-03-01

    Cerebral CT perfusion (CTP) imaging is playing an important role in the diagnosis and treatment of acute ischemic strokes. Meanwhile, the reliability of CTP-based ischemic lesion detection has been challenged due to the noisy appearance and low signal-to-noise ratio of CTP maps. To reduce noise and improve image quality, a rigorous study on the noise transfer properties of CTP systems is highly desirable to provide the needed scientific guidance. This paper concerns how noise in the CTP source images propagates to the final CTP maps. Both theoretical deviations and subsequent validation experiments demonstrated that, the noise level of background frames plays a dominant role in the noise of the cerebral blood volume (CBV) maps. This is in direct contradiction with the general belief that noise of non-background image frames is of greater importance in CTP imaging. The study found that when radiation doses delivered to the background frames and to all non-background frames are equal, lowest noise variance is achieved in the final CBV maps. This novel equality condition provides a practical means to optimize radiation dose delivery in CTP data acquisition: radiation exposures should be modulated between background frames and non-background frames so that the above equality condition is satisïnAed. For several typical CTP acquisition protocols, numerical simulations and in vivo canine experiment demonstrated that noise of CBV can be effectively reduced using the proposed exposure modulation method.

  8. Subnormothermic Perfusion in the Isolated Rat Liver Preserves the Antioxidant Glutathione and Enhances the Function of the Ubiquitin Proteasome System

    PubMed Central

    Alva, Norma; Sanchez-Nuño, Sergio; Dewey, Shannamar; Gomes, Aldrin V.

    2016-01-01

    The reduction of oxidative stress is suggested to be one of the main mechanisms to explain the benefits of subnormothermic perfusion against ischemic liver damage. In this study we investigated the early cellular mechanisms induced in isolated rat livers after 15 min perfusion at temperatures ranging from normothermia (37°C) to subnormothermia (26°C and 22°C). Subnormothermic perfusion was found to maintain hepatic viability. Perfusion at 22°C raised reduced glutathione levels and the activity of glutathione reductase; however, lipid and protein oxidation still occurred as determined by malondialdehyde, 4-hydroxynonenal-protein adducts, and advanced oxidation protein products. In livers perfused at 22°C the lysosomal and ubiquitin proteasome system (UPS) were both activated. The 26S chymotrypsin-like (β5) proteasome activity was significantly increased in the 26°C (46%) and 22°C (42%) groups. The increased proteasome activity may be due to increased Rpt6 Ser120 phosphorylation, which is known to enhance 26S proteasome activity. Together, our results indicate that the early events produced by subnormothermic perfusion in the liver can induce oxidative stress concomitantly with antioxidant glutathione preservation and enhanced function of the lysosomal and UPS systems. Thus, a brief hypothermia could trigger antioxidant mechanisms and may be functioning as a preconditioning stimulus. PMID:27800122

  9. Assessment of cardiac function using myocardial perfusion imaging technique on SPECT with 99mTc sestamibi

    NASA Astrophysics Data System (ADS)

    Gani, M. R. A.; Nazir, F.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    Suspicion on coronary heart disease can be confirmed by observing the function of left ventricle cardiac muscle with Myocardial Perfusion Imaging techniques. The function perfusion itself is indicated by the uptake of radiopharmaceutical tracer. The 31 patients were studied undergoing the MPI examination on Gatot Soebroto Hospital using 99mTc-sestamibi radiopharmaceutical with stress and rest conditions. Stress was stimulated by physical exercise or pharmacological agent. After two hours, the patient did rest condition on the same day. The difference of uptake percentage between stress and rest conditions will be used to determine the malfunction of perfusion due to ischemic or infarct. Degradation of cardiac function was determined based on the image-based assessment of five segments of left ventricle cardiac. As a result, 8 (25.8%) patients had normal myocardial perfusion and 11 (35.5%) patients suspected for having partial ischemia. Total ischemia occurred to 8 (25.8%) patients with reversible and irreversible ischemia and the remaining 4 (12.9%) patients for partial infarct with characteristic the percentage of perfusion ≤50%. It is concluded that MPI technique of image-based assessment on uptake percentage difference between stress and rest conditions can be employed to predict abnormal perfusion as complementary information to diagnose the cardiac function.

  10. Radionuclide behavior in the environment

    SciTech Connect

    Tveten, U. )

    1991-09-01

    The purpose of this report is to document the results of the following task: Review for quality and consistency the available data on measurements of initial ground contamination of Chernobyl radionuclides in various parts of Norway and subsequent concentrations of these radionuclides in various environmental media as functions of time. Utilize the data obtained to verify the existing models, or to improve them, for describing radionuclide behavior in the environment. Some of the processes standard were: migration into soil; weathering; resuspension; food-chain contamination; and loss or reconcentration by run-off. The task performed within this contract has been to use post-Chernobyl data from Norway to verify or find areas for possible improvement in the chronic exposure pathway models utilized in MACCS. Work has consisted mainly of collecting and evaluating post-Chernobyl information from Norway or other countries when relevant; but has also included experimental work performed specifically for the current task. In most connections the data available show the models and data in MACCS to be appropriate. A few areas where the data indicate that the MACCS approach is faulty or inadequate are, however, pointed out in the report. These should be examined carefully, and appropriate modifications should eventually be made. 14 refs., 12 figs., 22 tabs.

  11. Thallium-201 myocardial perfusion imaging in myocarditis

    SciTech Connect

    Tamaki, N.; Yonekura, Y.; Kadota, K.; Kambara, H.; Torizuka, K.

    1985-08-01

    TI-201 myocardial perfusion imaging was performed in six patients with clinically documented myocarditis. Each case manifested electrocardiographic abnormalities with elevation of serum cardiac enzymes and no significant stenosis of the coronary arteries observed on angiogram. Resting TI-201 images were visually assessed by three observers. Focal perfusion defects were observed in three cases (50%), among which two showed multiple perfusion defects. Emission computed tomography using TI-201 clearly delineated multifocal lesions in the first case. On the other hand, no significant perfusion defects were noted in the remaining three cases. Thus, myocarditis should be considered as one of the disease entities that may produce perfusion defects on TI-201 myocardial imaging.

  12. Radionuclide evaluation of left-ventricular function in chronic Chagas' cardiomyopathy

    SciTech Connect

    Arreaza, N.; Puigbo, J.J.; Acquatella, H. Casal, H.; Giordano, H.; Valecillos, R.; Mendoza, I.; Perez, J.F.; Hirschhaut, E.; Combellas, I.

    1983-07-01

    Left-ventricular ejection fraction (LVEF) and abnormalities of regional wall motion (WMA) were studied by means of radionuclide ventriculography in 41 patients prospectively diagnosed as having chronic Chagas' disease. Thirteen patients were asymptomatic (ASY), 16 were arrhythmic (ARR), and 12 had congestive heart failure (CHF). Mean LVEF was normal in ASY but markedly depressed in CHF. Regional WMAs were minimal in ASY and their severity increased in ARR. Most CHFs (75%) had diffuse hypokinesia of the left ventricle. Seven patients had a distinct apical aneurysm. Correlation between radionuclide and contrast ventriculography data was good in 17 patients. Selective coronary arteriography showed normal arteries in all patients. Therefore, chronic Chagas' heart disease joins ischemic heart disease as a cause of regional WMA.

  13. Radionuclide daughter inventory generator code: DIG

    SciTech Connect

    Fields, D.E.; Sharp, R.D.

    1985-09-01

    The Daughter Inventory Generator (DIG) code accepts a tabulation of radionuclide initially present in a waste stream, specified as amounts present either by mass or by activity, and produces a tabulation of radionuclides present after a user-specified elapsed time. This resultant radionuclide inventory characterizes wastes that have undergone daughter ingrowth during subsequent processes, such as leaching and transport, and includes daughter radionuclides that should be considered in these subsequent processes or for inclusion in a pollutant source term. Output of the DIG code also summarizes radionuclide decay constants. The DIG code was developed specifically to assist the user of the PRESTO-II methodology and code in preparing data sets and accounting for possible daughter ingrowth in wastes buried in shallow-land disposal areas. The DIG code is also useful in preparing data sets for the PRESTO-EPA code. Daughter ingrowth in buried radionuclides and in radionuclides that have been leached from the wastes and are undergoing hydrologic transport are considered, and the quantities of daughter radionuclide are calculated. Radionuclide decay constants generated by DIG and included in the DIG output are required in the PRESTO-II code input data set. The DIG accesses some subroutines written for use with the CRRIS system and accesses files containing radionuclide data compiled by D.C. Kocher. 11 refs.

  14. Does machine perfusion decrease ischemia reperfusion injury?

    PubMed

    Bon, D; Delpech, P-O; Chatauret, N; Hauet, T; Badet, L; Barrou, B

    2014-06-01

    In 1990's, use of machine perfusion for organ preservation has been abandoned because of improvement of preservation solutions, efficient without perfusion, easy to use and cheaper. Since the last 15 years, a renewed interest for machine perfusion emerged based on studies performed on preclinical model and seems to make consensus in case of expanded criteria donors or deceased after cardiac death donations. We present relevant studies highlighted the efficiency of preservation with hypothermic machine perfusion compared to static cold storage. Machines for organ preservation being in constant evolution, we also summarized recent developments included direct oxygenation of the perfusat. Machine perfusion technology also enables organ reconditioning during the last hours of preservation through a short period of perfusion on hypothermia, subnormothermia or normothermia. We present significant or low advantages for machine perfusion against ischemia reperfusion injuries regarding at least one primary parameter: risk of DFG, organ function or graft survival.

  15. Methods of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, L.A.; Ryan, J.L.

    1998-09-15

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of {sup 223}Ra and {sup 225}Ac, from a radionuclide ``cow`` of {sup 227}Ac or {sup 229}Th respectively. The method comprises the steps of (a) permitting ingrowth of at least one radionuclide daughter from said radionuclide ``cow`` forming an ingrown mixture; (b) insuring that the ingrown mixture is a nitric acid ingrown mixture; (c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the ``cow`` from at least one radionuclide daughter; (d) insuring that the at least one radionuclide daughter contains the radionuclide product; (e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and (f) recycling the at least one radionuclide daughter by adding it to the ``cow``. In one embodiment the radionuclide ``cow`` is the {sup 227}Ac, the at least one daughter radionuclide is a {sup 227}Th and the product radionuclide is the {sup 223}Ra and the first nitrate form ion exchange column passes the {sup 227}Ac and retains the {sup 227}Th. In another embodiment the radionuclide ``cow`` is the {sup 229}Th, the at least one daughter radionuclide is a {sup 225}Ra and said product radionuclide is the {sup 225}Ac and the {sup 225}Ac and nitrate form ion exchange column retains the {sup 229}Th and passes the {sup 225}Ra/Ac. 8 figs.

  16. Methods of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, Lane A.; Ryan, Jack L.

    1998-01-01

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of .sup.223 Ra and .sup.225 Ac, from a radionuclide "cow" of .sup.227 Ac or .sup.229 Th respectively. The method comprises the steps of a) permitting ingrowth of at least one radionuclide daughter from said radionuclide "cow" forming an ingrown mixture; b) insuring that the ingrown mixture is a nitric acid ingrown mixture; c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the "cow" from at least one radionuclide daughter; d) insuring that the at least one radionuclide daughter contains the radionuclide product; e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and f) recycling the at least one radionuclide daughter by adding it to the "cow". In one embodiment the radionuclide "cow" is the .sup.227 Ac, the at least one daughter radionuclide is a .sup.227 Th and the product radionuclide is the .sup.223 Ra and the first nitrate form ion exchange column passes the .sup.227 Ac and retains the .sup.227 Th. In another embodiment the radionuclide "cow"is the .sup.229 Th, the at least one daughter radionuclide is a .sup.225 Ra and said product radionuclide is the .sup.225 Ac and the .sup.225 Ac and nitrate form ion exchange column retains the .sup.229 Th and passes the .sup.225 Ra/Ac.

  17. Peripheral arterial disease diagnosed with high-count-rate radionuclide arteriography

    SciTech Connect

    Oshima, M.; Ijima, H.; Kohda, Y.; Kuramoto, K.; Kikuchi, Y.; Wada, M.; Akisada, M.

    1984-07-01

    Thirty-seven patients with peripheral vascular disease involving the legs were studied with first-pass peripheral radio-nuclide arteriography (RNA) and contrast arteriography to determine whether RNA could be used to evaluate perfusion of the toes. Peripheral time-activity curves were examined and the time required for activity to decline to 75% of peak activity (T75) was recorded. These data suggest that peripheral RNA of the toes is a reliable, noninvasive procedure for evaluation of peripheral arterial disease; it can be valuable as a screening test prior to contrast arteriography as well as for follow-up.

  18. Comparison of radionuclide and enzymatic estimate of infarct size in patients with acute myocardial infarction

    SciTech Connect

    Hirsowitz, G.S.; Lakier, J.B.; Marks, D.S.; Lee, T.G.; Goldberg, A.D.; Goldstein, S.

    1983-06-01

    A comparison was made of the estimated size of the myocardial infarction occurring in 26 patients with a first infarction using creatine kinase (CK) enzyme release between radionuclide gated blood pool measurement of total and regional ventricular function and thallium-201 scintigraphic measurement of myocardial perfusion defects. Creatine kinase estimates of infarct size (enzymatic infarct size) correlated closely with the percent of abnormal contracting regions, left ventricular ejection fraction and thallium-201 estimates of percent of abnormal perfusion area (r . 0.78, 0.69 and 0.74, respectively, p less than 0.01). A close correlation also existed between percent abnormal perfusion area and percent of abnormal contracting regions (r . 0.81, p less than 0.01) and left ventricular ejection fraction (r . 0.69, p less than 0.01). Enzymatic infarct size was larger in anterior (116 +/- 37 CK-g-Eq) than inferior (52 +/- 29 CK-g-Eq) myocardial infarction (p less than 0.01) and was associated with significantly more left ventricular functional impairment as determined by left ventricular ejection fraction (33 +/- 7 versus 60 +/- 10%) (p less than 0.01) and percent abnormal perfusion area (58 +/- 14 versus 13 +/- 12) (p less than 0.01). No significant correlation was observed between enzymatic infarct size and right ventricular ejection fraction. These different methods of estimating infarct size correlated closely with each other in these patients with a first uncomplicated myocardial infarction.

  19. [Comparison of various parameters for determining an index of myocardial perfusion reserve in detecting coronary stenosis with cardiovascular magnetic resonance tomography].

    PubMed

    al-Saadi, N; Gross, M; Bornstedt, A; Schnackenburg, B; Klein, C; Fleck, E; Nagel, E

    2001-11-01

    For the assessment of myocardial perfusion with cardiac magnetic resonance imaging, different semiquantitative parameters of the first pass signal intensity time curves can be calculated and myocardial perfusion reserve indices can be determined. In this study we evaluated the feasibility of different perfusion parameters and their perfusion reserve indices for the detection of significant coronary artery stenosis. The signal intensity time curves of the first pass of a gadolinium-DTPA bolus injected via a central vein catheter before and after dipyridamole infusion were investigated in 15 patients with single vessel (stenosis > or = 75% area reduction) and five patients without significant coronary artery disease. For the distinction of ischemic and nonischemic myocardial segments, semiquantitative parameters, such as maximal signal intensity, contrast appearance time, time to maximal signal intensity and the steepness of the signal intensity curve's upslope determined by a linear fit, were assessed after correction for the input function. For each parameter a myocardial perfusion reserve index was calculated and cut off values for the detection of significant coronary stenosis were defined. The diagnostic accuracy of each parameter was then examined prospectively in 36 patients with coronary artery disease and compared with coronary angiography. Where as a distinction of ischemic and normal myocardium was possible with myocardial perfusion reserve indices, semiquantitative parameters at rest or after vasodilation alone did not allow such a distinction. The perfusion reserve index calculated from the upslope showed the most significant difference between ischemic and nonischemic myocardial segments (1.19 +/- 0.4 and 2.38 +/- 0.45, p < 0.001) followed by maximum signal intensity, time to maximum signal intensity and contrast apperance time. Sensitivity, specificity and diagnostic accuracy was 87, 82 and 85% for the detection of hypoperfusion induced by significant

  20. Real-time ultrasound brain perfusion imaging with analysis of microbubble replenishment in acute MCA stroke.

    PubMed

    Kern, Rolf; Diels, Anna; Pettenpohl, Johanna; Kablau, Micha; Brade, Joachim; Hennerici, Michael G; Meairs, Stephen

    2011-08-01

    Real-time ultrasound perfusion imaging (rt-UPI) allows visualization of microbubbles flowing through the cerebral microvasculature. We hypothesized that analysis of microbubble tissue replenishment would enable for characterization of perfusion deficits in acute middle cerebral artery (MCA) territory stroke. Twenty-three patients (mean age 70.2 ± 13.2 years, 9 weeks) were included. Sequential images of bubble replenishment were acquired by transcranial rt-UPI at low mechanical index immediately after microbubble destruction. Different parameters were calculated from regions of interest (ROIs): real-time time to peak (rt-TTP), rise rate (β), and plateau (A) of acoustic intensity, and A × β was used as an index of blood flow. Results were compared with diffusion-weighted and perfusion magnetic resonance imaging. Parameters of rt-UPI had lower values in ROIs of ischemic as compared with normal tissue (β=0.58 ± 0.40 versus 1.25 ± 0.83; P=0.001; A=1.44 ± 1.75 versus 2.63 ± 2.31; P=0.05; A × β=1.14 ± 2.25 versus 2.98 ± 2.70; P=0.01). Real-time time to peak was delayed in ischemic tissue (11.43 ± 2.67 versus 8.88 ± 1.66 seconds; P<0.001). From the analysis of receiver operating characteristic curves, β and A × β had the largest areas under the curve with optimal cutoff values of β<0.76 and A × β<1.91. We conclude that rt-UPI with analysis of microbubble replenishment correctly identifies ischemic brain tissue in acute MCA stroke.

  1. A reappraisal of the definition and pathophysiology of the transient ischemic attack.

    PubMed

    Hadjiev, Dimiter Ivanov; Mineva, Petya Pencheva

    2007-03-01

    Recent data on the pathophysiology of brain ischemia obtained by neuroimaging methods and the new concept of transient ischemic attack (TIA) emergency have called for a redefinition of TIA. According to the new definition proposed by the TIA Working Group, TIA is a brief episode of neurological dysfunction caused by focal brain or retinal ischemia with clinical symptoms typically lasting less than one hour and without evidence of acute brain infarction. This new definition leads to a discussion on the duration of the neurological dysfunction and the availability of appropriate neuroimaging for all patients. It has been reported that the diffusion-weighted imaging abnormalities could be seen in TIA patients with durations of the neurological symptoms of less than 30 minutes, but they were not detected in 29% of patients with transient deficit lasting as much as 6 to 24 hours. Persisting perfusion abnormalities in TIA patients are also observed. Therefore, a cutoff period of any duration of TIA is inaccurate. From the pathophysiological viewpoint, TIA may be considered an ischemic penumbra of varied duration, which could proceed to cerebral infarction or reduce to benign oligemia. TIA, characterized as an ischemic penumbra, presents an ideal target for rapid reperfusion and neuroprotection. Follow-up perfusion imaging can guide and individualize its treatment.

  2. Routine Use of Distal Arterial Perfusion in Pediatric Femoral Venoarterial Extracorporeal Membrane Oxygenation.

    PubMed

    Schad, Christine A; Fallon, Brian P; Monteagudo, Julie; Okochi, Shunpei; Cheung, Eva W; Morrissey, Nicholas J; Kadenhe-Chiweshe, Angela V; Aspelund, Gudrun; Stylianos, Steven; Middlesworth, William

    2017-01-01

    Lower-extremity ischemia is a significant complication in children on femoral venoarterial extracorporeal membrane oxygenation (VA ECMO). Our institution currently routinely uses distal perfusion catheters (DPCs) in all femoral arterial cannulations in attempts to reduce ischemia. We performed a single-center, retrospective review of pediatric patients supported with femoral VA ECMO from January 2005 to November 2015. The outcomes of patients with prophylactic DPC placement at cannulation (prophylactic DPC) were compared to a historical group with DPCs placed in response only to clinically evident ischemic changes (reactive DPC). Ischemic complication requiring invasive intervention (fasciotomy or amputation) was the primary outcome. Twenty-nine patients underwent a total of 31 femoral arterial cannulations, 17 with prophylactic DPC and 14 with reactive DPC. Ischemic complications requiring invasive intervention developed in 2 of 17 (12%) prophylactic DPC patients versus 4 of 14 (29%) reactive DPC. In the reactive DPC group, 7 of 14 (50%) had ischemic changes postcannulation, six underwent DPC placement, and three out of six of these patients still required invasive intervention. One of the seven patients had ischemic changes, did not undergo DPC, and required amputation. While a greater percentage of patients in the prophylactic group was cannulated during extracorporeal cardiopulmonary resuscitation (ECPR), statistical significance was not otherwise demonstrated. We demonstrate feasibility of superficial femoral artery (SFA) access in pediatric patients. We note fewer ischemic complications with prophylactic DPC placement, and observe that salvaging a limb with a reactive DPC was only successful 50% of the time. Although there was no statistical difference in the primary outcome between the two groups, limitations and confounding factors include small sample size and a greater percentage of patients in the prophylactic DPC group cannulated with ECPR in progress.

  3. Thrombospondin-1 limits ischemic tissue survival by inhibiting nitric oxide–mediated vascular smooth muscle relaxation

    PubMed Central

    Isenberg, Jeff S.; Hyodo, Fuminori; Matsumoto, Ken-Ichiro; Romeo, Martin J.; Abu-Asab, Mones; Tsokos, Maria; Kuppusamy, Periannan; Wink, David A.; Krishna, Murali C.

    2007-01-01

    The nitric oxide (NO)/cGMP pathway, by relaxing vascular smooth muscle cells, is a major physiologic regulator of tissue perfusion. We now identify thrombospondin-1 as a potent antagonist of NO for regulating F-actin assembly and myosin light chain phosphorylation in vascular smooth muscle cells. Thrombospondin-1 prevents NO-mediated relaxation of precontracted vascular smooth muscle cells in a collagen matrix. Functional magnetic resonance imaging demonstrated that an NO-mediated increase in skeletal muscle perfusion was enhanced in thrombospondin-1–null relative to wild-type mice, implicating endogenous thrombospondin-1 as a physiologic antagonist of NO-mediated vasodilation. Using a random myocutaneous flap model for ischemic injury, tissue survival was significantly enhanced in thrombospondin-1–null mice. Improved flap survival correlated with increased recovery of oxygen levels in the ischemic tissue of thrombospondin-1–null mice as measured by electron paramagnetic resonance oximetry. These findings demonstrate an important antag-onistic relation between NO/cGMP signaling and thrombospondin-1 in vascular smooth muscle cells to regulate vascular tone and tissue perfusion. PMID:17082319

  4. Direct effects of smoking on the heart: silent ischemic disturbances of coronary flow

    SciTech Connect

    Deanfield, J.E.; Shea, M.J.; Wilson, R.A.; Horlock, P.; de Landsheere, C.M.; Selwyn, A.P.

    1986-05-01

    Cigarette smoking is strongly associated with ischemic heart disease and acute coronary events. The effect of smoking a single cigarette on regional myocardial perfusion was studied in 13 chronic smokers with typical stable angina pectoris using positron emission tomography and rubidium-82 (/sup 82/Rb). Findings were compared with the effects of physical exercise. After exercise, 8 patients (61%) had angina, ST depression and abnormal regional myocardial perfusion. Uptake of /sup 82/Rb increased from 49 +/- 8 to 60 +/- 7 in remote myocardium, but decreased from 46 +/- 3 to 37 +/- 5 in an ischemic area. The remaining 5 patients (39%) had homogeneous increases in /sup 82/Rb uptake without angina or ST depression. After smoking, 6 of the 8 patients with positive exercise test responses had a decrease in /sup 82/Rb uptake, from 47 +/- 3 to 35 +/- 6 in the same segment of myocardium affected during exercise. However, in contrast to exercise, the events during smoking were largely silent. The absolute decreases in regional /sup 82/Rb uptake after smoking occurred at significantly lower levels of myocardial oxygen demand than after exercise. This suggests that an impairment of coronary blood supply is responsible. Thus, in smokers with coronary artery disease, each cigarette can cause profound silent disturbances of regional myocardial perfusion that are likely to occur frequently during daily life. Such repeated insults may represent an important mechanism linking smoking with coronary events.

  5. Microbial Transformations of Actinides and Other Radionuclides

    SciTech Connect

    Francis,A.J.; Dodge, C. J.

    2009-01-07

    Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been extensively investigated, we have only limited information on the effects of microbial processes and biochemical mechanisms which affect the stability and mobility of radionuclides. The mechanisms of microbial transformations of the major and minor actinides U, Pu, Cm, Am, Np, the fission products and other radionuclides such as Ra, Tc, I, Cs, Sr, under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  6. Chemical speciation of radionuclides migrating in groundwaters

    SciTech Connect

    Robertson, D.; Schilk, A.; Abel, K.; Lepel, E.; Thomas, C.; Pratt, S.; Cooper, E.; Hartwig, P.; Killey, R.

    1994-04-01

    In order to more accurately predict the rates and mechanisms of radionuclide migration from low-level waste disposal facilities via groundwater transport, ongoing studies are being conducted at field sites at Chalk River Laboratories to identify and characterize the chemical speciation of mobile, long-lived radionuclides migrating in groundwaters. Large-volume water sampling techniques are being utilized to separate and concentrate radionuclides into particular, cationic, anionic, and nonionic chemical forms. Most radionuclides are migrating as soluble, anionic species that appear to be predominantly organoradionuclide complexes. Laboratory studies utilizing anion exchange chromatography have separated several anionically complexed radionuclides, e.g., {sup 60}Co and {sup 106}Ru, into a number of specific compounds or groups of compounds. Further identification of the anionic organoradionuclide complexes is planned utilizing high resolution mass spectrometry. Large-volume ultra-filtration experiments are characterizing the particulate forms of radionuclides being transported in these groundwaters.

  7. Targeted Radionuclide Therapy of Human Tumors

    PubMed Central

    Gudkov, Sergey V.; Shilyagina, Natalya Yu.; Vodeneev, Vladimir A.; Zvyagin, Andrei V.

    2015-01-01

    Targeted radionuclide therapy is one of the most intensively developing directions of nuclear medicine. Unlike conventional external beam therapy, the targeted radionuclide therapy causes less collateral damage to normal tissues and allows targeted drug delivery to a clinically diagnosed neoplastic malformations, as well as metastasized cells and cellular clusters, thus providing systemic therapy of cancer. The methods of targeted radionuclide therapy are based on the use of molecular carriers of radionuclides with high affinity to antigens on the surface of tumor cells. The potential of targeted radionuclide therapy has markedly grown nowadays due to the expanded knowledge base in cancer biology, bioengineering, and radiochemistry. In this review, progress in the radionuclide therapy of hematological malignancies and approaches for treatment of solid tumors is addressed. PMID:26729091

  8. Challenges in machine perfusion preservation for liver grafts from donation after circulatory death

    PubMed Central

    2013-01-01

    Donation after circulatory death (DCD) is a promising solution to the critical shortage of donor graft tissue. Maintaining organ viability after donation until transplantation is essential for optimal graft function and survival. To date, static cold storage is the most widely used form of preservation in clinical practice. However, ischemic damage present in DCD grafts jeopardizes organ viability during cold storage, and whether static cold storage is the most effective method to prevent deterioration of organ quality in the increasing numbers of organs from DCD is unknown. Here we describe the historical background of DCD liver grafts and a new preservation method for experimental and clinical transplantation. To prevent ischemia-reperfusion injury in DCD liver grafts, a hypothermic machine perfusion (HMP) technique has recently been developed and may be superior to static cold preservation. We present evidence supporting the need for improving liver perfusion performance and discuss how doing so will benefit liver transplantation recipients. PMID:24283383

  9. DKPRO: A radionuclide decay and reprocessing code

    SciTech Connect

    Wootan, D.; Schmittroth, F.A.

    1997-07-14

    The DKPRO code solves the general problem of modeling complex nuclear wastes streams using ORIGEN2 radionuclide production files. There is a continuing need for estimates of Hanford radionuclides. Physical measurements are one basis; calculational estimates, the approach represented here, are another. Given a known nuclear fuel history, it is relatively straightforward to calculate radionuclide inventories with codes such as the widely-used Oak Ridge National Laboratory code ORIGEN2.

  10. Colloid labelled with radionuclide and method

    DOEpatents

    Atcher, R.W.; Hines, J.J.

    1990-11-13

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints. No Drawings

  11. Method of making colloid labeled with radionuclide

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1991-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  12. Colloid labelled with radionuclide and method

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1990-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  13. Functional recovery of hibernating myocardium after coronary bypass surgery: Does it coincide with improvement in perfusion

    SciTech Connect

    Takeishi, Y.; Tono-oka, I.; Kubota, I.; Ikeda, K.; Masakane, I.; Chiba, J.; Abe, S.; Tsuiki, K.; Komatani, A.; Yamaguchi, I. )

    1991-09-01

    To determine the relationship between functional recovery and improvement in perfusion after coronary artery bypass graft surgery (CABG), 49 patients were studied. Radionuclide angiography was performed before, 1 month after, and 6 to 12 months after CABG to evaluate regional wall motion. Exercise thallium-201 myocardial perfusion imaging was done before and 1 month after CABG to assess regional perfusion. Preoperative asynergy was observed in 108 segments, and 74 of them showed an improvement in wall motion 1 month after CABG (segment A). Sixty-six of these segments (89%) were associated with an improvement in perfusion. Eight segments that had not improved 1 month after CABG demonstrated a delayed recovery of wall motion 6 to 12 months after CABG (segment B). However, seven of eight segments (88%) already showed an improvement in perfusion 1 month after CABG. A total of 82 segments exhibited functional recovery after CABG and were considered hibernating segments. In the preoperative study segment B more frequently had areas of akinesis or dyskinesis than segment A (75% vs 34%, p less than 0.05). The mean percent thallium-201 uptake in segment B was lower than that in segment A (74% {plus minus} 9% vs 83% {plus minus} 8%, p less than 0.05). Functional recovery of hibernating myocardium usually coincided with an improvement in perfusion. However, delayed functional recovery after reperfusion was observed in some instances. Severe asynergy and severe thallium-201 defects were more frequently observed in these segments with delayed recovery. Hibernating myocardium might remain stunned during those recovery periods.

  14. Recurrent Bleeding in Hemorrhagic Moyamoya Disease : Prognostic Implications of the Perfusion Status

    PubMed Central

    Jo, Kyung-Il; Kim, Min Soo; Yeon, Je Young; Kim, Jong-Soo

    2016-01-01

    Objective Hemorrhagic moyamoya disease (hMMD) is associated with a poor clinical course. Furthermore, poorer clinical outcomes occur in cases of recurrent bleeding. However, the effect of hemodynamic insufficiency on rebleeding risk has not been investigated yet. This study evaluated the prognostic implications of the perfusion status during the clinical course of adult hMMD. Methods This retrospective study enrolled 52 adult hMMD patients between April 1995 and October 2010 from a single institute. Demographic data, clinical and radiologic characteristics, including hemodynamic status using single photon emission computed tomography (SPECT), and follow up data were obtained via a retrospective review of medical charts and imaging. Statistical analyses were performed to explore potential prognostic factors. Results Hemodynamic abnormality was identified in 44 (84.6%) patients. Subsequent revascularization surgery was performed in 22 (42.3%) patients. During a 58-month (median, range 3–160) follow-up assessment period, 17 showed subsequent stroke (hemorrhagic n=12, ischemic n=5, Actuarial stroke rate 5.8±1.4%/year). Recurrent hemorrhage was associated with decreased basal perfusion (HR 19.872; 95% CI=1.196–294.117) and omission of revascularization (10.218; 95%; CI=1.532–68.136). Conclusion Decreased basal perfusion seems to be associated with recurrent bleeding. Revascularization might prevent recurrent stroke in hMMD by rectifying the perfusion abnormality. A larger-sized, controlled study is required to address this issue. PMID:26962416

  15. Dipyridamole-thallium-201 tomography documenting improved myocardial perfusion with therapy in Kawasaki disease

    SciTech Connect

    Nienaber, C.A.; Spielmann, R.P.; Hausdorf, G.

    1988-12-01

    Thallium-201 tomographic perfusion studies after pharmacologic vasodilation were performed in seven children (aged 2 years 8 months to 8 years 7 months), 3 to 20 months after the acute stage of the disease. In all patients coronary aneurysms were seen on cross-sectional echocardiograms. The scintigrams of six children showed no significant regional reduction of myocardial thallium-201 uptake. These children had remained asymptomatic in the follow-up period after the acute inflammatory stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with acute posterolateral myocardial infarction; obstruction of two coronary vessels supplying the defect zones was confirmed by contrast angiography. After 8 months of treatment a follow-up nuclear scan showed marked reduction in the size of the defect and almost complete abolishment of the ischemic reaction. Thus tomographic thallium-201 perfusion scintigraphy in conjunction with vasodilation stress is useful to assess myocardial perfusion in children with Kawasaki disease and demonstrates marked improvement in regional perfusion after adequate medical therapy.

  16. Initial testing of a 3D printed perfusion phantom using digital subtraction angiography

    PubMed Central

    Khobragade, Parag; Ying, Leslie; Snyder, Kenneth; Wack, David; Bednarek, Daniel R.; Rudin, Stephen; Ionita, Ciprian N.

    2015-01-01

    Perfusion imaging is the most applied modality for the assessment of acute stroke. Parameters such as Cerebral Blood Flow (CBF), Cerebral Blood volume (CBV) and Mean Transit Time (MTT) are used to distinguish the tissue infarct core and ischemic penumbra. Due to lack of standardization these parameters vary significantly between vendors and software even when provided with the same data set. There is a critical need to standardize the systems and make them more reliable. We have designed a uniform phantom to test and verify the perfusion systems. We implemented a flow loop with different flow rates (250, 300, 350 ml/min) and injected the same amount of contrast. The images of the phantom were acquired using a Digital Angiographic system. Since this phantom is uniform, projection images obtained using DSA is sufficient for initial validation. To validate the phantom we measured the contrast concentration at three regions of interest (arterial input, venous output, perfused area) and derived time density curves (TDC). We then calculated the maximum slope, area under the TDCs and flow. The maximum slope calculations were linearly increasing with increase in flow rate, the area under the curve decreases with increase in flow rate. There was 25% error between the calculated flow and measured flow. The derived TDCs were clinically relevant and the calculated flow, maximum slope and areas under the curve were sensitive to the measured flow. We have created a systematic way to calibrate existing perfusion systems and assess their reliability. PMID:26633914

  17. DRAG REDUCING POLYMER ENCHANCES MICROVASCULAR PERFUSION IN THE TRAUMATIZED BRAIN WITH INTRACRANIAL HYPERTENSION

    PubMed Central

    Bragin, Denis E.; Thomson, Susan; Bragina, Olga; Statom, Gloria; Kameneva, Marina V.; Nemoto, Edwin M.

    2016-01-01

    SUMMARY Current treatments for traumatic brain injury (TBI) have not focused on improving microvascular perfusion. Drag-reducing polymers (DRP), linear, long-chain, blood soluble non-toxic macromolecules, may offer a new approach to improving cerebral perfusion by primary alteration of the fluid dynamic properties of blood. Nanomolar concentrations of DRP have been shown to improve hemodynamics in animal models of ischemic myocardium and limb, but have not yet been studied in the brain. Recently, we demonstrated that that DRP improved microvascular perfusion and tissue oxygenation in a normal rat brain. We hypothesized that DRP could restore microvascular perfusion in hypertensive brain after TBI. Using the in-vivo 2-photon laser scanning microscopy we examined the effect of DRP on microvascular blood flow and tissue oxygenation in hypertensive rat brains with and without TBI. DRP enhanced and restored capillary flow, decreased microvascular shunt flow and, as a result, reduced tissue hypoxia in both un-traumatized and traumatized rat brains at high ICP. Our study suggests that DRP could be an effective treatment for improving microvascular flow in brain ischemia caused by high ICP after TBI. PMID:27165871

  18. Initial testing of a 3D printed perfusion phantom using digital subtraction angiography

    NASA Astrophysics Data System (ADS)

    Wood, Rachel P.; Khobragade, Parag; Ying, Leslie; Snyder, Kenneth; Wack, David; Bednarek, Daniel R.; Rudin, Stephen; Ionita, Ciprian N.

    2015-03-01

    Perfusion imaging is the most applied modality for the assessment of acute stroke. Parameters such as Cerebral Blood Flow (CBF), Cerebral Blood volume (CBV) and Mean Transit Time (MTT) are used to distinguish the tissue infarct core and ischemic penumbra. Due to lack of standardization these parameters vary significantly between vendors and software even when provided with the same data set. There is a critical need to standardize the systems and make them more reliable. We have designed a uniform phantom to test and verify the perfusion systems. We implemented a flow loop with different flow rates (250, 300, 350 ml/min) and injected the same amount of contrast. The images of the phantom were acquired using a Digital Angiographic system. Since this phantom is uniform, projection images obtained using DSA is sufficient for initial validation. To validate the phantom we measured the contrast concentration at three regions of interest (arterial input, venous output, perfused area) and derived time density curves (TDC). We then calculated the maximum slope, area under the TDCs and flow. The maximum slope calculations were linearly increasing with increase in flow rate, the area under the curve decreases with increase in flow rate. There was 25% error between the calculated flow and measured flow. The derived TDCs were clinically relevant and the calculated flow, maximum slope and areas under the curve were sensitive to the measured flow. We have created a systematic way to calibrate existing perfusion systems and assess their reliability.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Normothermic Ex Vivo Kidney Perfusion for the Preservation of Kidney Grafts prior to Transplantation

    PubMed Central

    Kaths, J. Moritz; Spetzler, Vinzent N.; Goldaracena, Nicolas; Echeverri, Juan; Louis, Kristine S.; Foltys, Daniel B.; Strempel, Mari; Yip, Paul; John, Rohan; Mucsi, Istvan; Ghanekar, Anand; Bagli, Darius; Robinson, Lisa; Selzner, Markus

    2015-01-01

    Kidney transplantation has become a well-established treatment option for patients with end-stage renal failure. The persisting organ shortage remains a serious problem. Therefore, the acceptance criteria for organ donors have been extended leading to the usage of marginal kidney grafts. These marginal organs tolerate cold storage poorly resulting in increased preservation injury and higher rates of delayed graft function. To overcome the limitations of cold storage, extensive research is focused on alternative normothermic preservation methods. Ex vivo normothermic organ perfusion is an innovative preservation technique. The first experimental and clinical trials for ex vivo lung, liver, and kidney perfusions demonstrated favorable outcomes. In addition to the reduction of cold ischemic injury, the method of normothermic kidney storage offers the opportunity for organ assessment and repair. This manuscript provides information about kidney retrieval, organ preservation techniques, and isolated ex vivo normothermic kidney perfusion (NEVKP) in a porcine model. Surgical techniques, set up for the perfusion solution and the circuit, potential assessment options, and representative results are demonstrated. PMID:26275014

  1. Spontaneous changes in /sup 201/Tl myocardial perfusion imaging after myocardial infarction

    SciTech Connect

    Buda, A.J.; Dubbin, J.D.; MacDonald, I.L.; Strauss, H.D.; Orr, S.A.; Meindok, H.

    1982-12-01

    To examine regional myocardial perfusion after myocardial infarction, 26 patients underwent exercise electrocardiographic testing with /sup 201/Tl myocardial perfusion imaging 3 weeks and 3 months after infarction. At 3 weeks, 9 of 26 patients (35%) had myocardial ischemia by exercise electrocardiographic testing, whereas 18 of 26 (69%) had ischemia by /sup 201/Tl imaging. The /sup 201/Tl scintigrams were scored by dividing each image, in 3 views, into 5 segments, using a 5-point scoring scheme. The exercise /sup 201/Tl score was 44.3 +/- 1.2 and increased to 47.3 +/- 1.2 in the redistribution study (p less than 0.001). Three months after infarction, although there was a significantly greater rate-pressure product which would predict a larger ischemic defect and a decrease in the stress /sup 201/Tl score, the stress score was improved (48.3 +/- 1.1, p less than 0.001). The redistribution score was similar, that is, 48.9 +/- 1.0. The improvement in /sup 201/Tl myocardial perfusion was associated with a loss of stress-induced ischemia in 8 patients (30%). These results indicate that spontaneous improvements in /sup 201/Tl myocardial perfusion imaging may occur after myocardial infarction.

  2. Therapy for incorporated radionuclides: scope and need

    SciTech Connect

    Smith, V.H.

    1981-03-01

    In the United States the recent termination of funding for research on therapy for incorporated radionuclides has virtually halted progress on improved or new agents and procedures for removing radioactivity from the body. Research was eliminated, but is still needed on new removal agents, improved delivery system, in vitro test systems, and the toxicology of treatments. For many radionuclides, no adequate therapy exists. The relationship between radionuclide removal and reduction in cancer risk is still unanswered. Without proper research support, needed improvements in the treatment for incorporated radionuclides in the US are uncertain.

  3. Ion binding compounds, radionuclide complexes, methods of making radionuclide complexes, methods of extracting radionuclides, and methods of delivering radionuclides to target locations

    DOEpatents

    Chen, Xiaoyuan; Wai, Chien M.; Fisher, Darrell R.

    2000-01-01

    The invention pertains to compounds for binding lanthanide ions and actinide ions. The invention further pertains to compounds for binding radionuclides, and to methods of making radionuclide complexes. Also, the invention pertains to methods of extracting radionuclides. Additionally, the invention pertains to methods of delivering radionuclides to target locations. In one aspect, the invention includes a compound comprising: a) a calix[n]arene group, wherein n is an integer greater than 3, the calix[n]arene group comprising an upper rim and a lower rim; b) at least one ionizable group attached to the lower rim; and c) an ion selected from the group consisting of lanthanide and actinide elements bound to the ionizable group. In another aspect, the invention includes a method of extracting a radionuclide, comprising: a) providing a sample comprising a radionuclide; b) providing a calix[n]arene compound in contact with the sample, wherein n is an integer greater than 3; and c) extracting radionuclide from the sample into the calix[n]arene compound. In yet another aspect, the invention includes a method of delivering a radionuclide to a target location, comprising: a) providing a calix[n]arene compound, wherein n is an integer greater than 3, the calix[n]arene compound comprising at least one ionizable group; b) providing a radionuclide bound to the calix[n]arene compound; and c) providing an antibody attached to the calix[n]arene compound, the antibody being specific for a material found at the target location.

  4. Early Support of Intracranial Perfusion

    DTIC Science & Technology

    2013-10-01

    automated real-time vital signs monitoring data” was funded by USAF (MSA); UM PI: Deborah Stein  The project, titled “Noninvasive intracranial pressure ...scoring of cerebral perfusion pressure and intracranial pressure provides a Brain Trauma Index that predicts outcome in patients with severe TBI... intracranial pressure dose index: Dynamic 3-D scoring in the assessment of Traumatic Brain Injury Proceedings of American Association for the Surgery of

  5. A Generator-Produced Gallium-68 Radiopharmaceutical for PET Imaging of Myocardial Perfusion

    PubMed Central

    Sharma, Vijay; Sivapackiam, Jothilingam; Harpstrite, Scott E.; Prior, Julie L.; Gu, Hannah; Rath, Nigam P.; Piwnica-Worms, David

    2014-01-01

    Lipophilic cationic technetium-99m-complexes are widely used for myocardial perfusion imaging (MPI). However, inherent uncertainties in the supply chain of molybdenum-99, the parent isotope required for manufacturing 99Mo/99mTc generators, intensifies the need for discovery of novel MPI agents incorporating alternative radionuclides. Recently, germanium/gallium (Ge/Ga) generators capable of producing high quality 68Ga, an isotope with excellent emission characteristics for clinical PET imaging, have emerged. Herein, we report a novel 68Ga-complex identified through mechanism-based cell screening that holds promise as a generator-produced radiopharmaceutical for PET MPI. PMID:25353349

  6. In systemic sclerosis skin perfusion of hands is reduced and may predict the occurrence of new digital ulcers.

    PubMed

    Barbano, Biagio; Marra, Alessandro Maria; Quarta, Silvia; Gigante, Antonietta; Barilaro, Giuseppe; Gasperini, Maria Ludovica; Rosato, Edoardo

    2017-03-01

    Systemic sclerosis (SSc) patients are at high risk for the development of ischemic digital ulcers (DUs). The aim of this study was to assess in SSc patients a correlation between skin perfusion evaluated by LDPI and DUs and to evaluate the prognostic value of skin perfusion to predict the new DUs occurrence. Fifty eight (47 female, 11 male) SSc patients were enrolled. Skin perfusion of hands and region of interest (ROIs) was measured by Laser Doppler perfusion Imager (LDPI). The proximal-distal gradient (PDG) was present when the perfusion mean difference between ROI1 and ROI2 was >30 pU. The skin perfusion of hands is lower in SSc patients than in healthy controls. The skin perfusion decreased with severity of capillaroscopic damage. Both mean perfusion of hand and PDG are significantly (p<0.01 and p<0.0001, respectively) lower in SSc patients with new DUs than in SSc patients without DUs. Only 2 of 11 SSc patients (18.2%) with PDG developed new digital ulcers, conversely 36 of 47 (76.6%) SSc patients without PDG developed new digital ulcers (p<0.001). The ROC curves demonstrated a good accuracy of new DUs prediction for PDG (0.78, p<0.0001). Using this cut-off value of 30 pU, RR for new DUs development in SSc patients without PDG is 4,2 (p<0.001). LDPI indices could be used in association to the capillaroscopic and clinical findings or serological tests in the identification of patients at high risk of developing DUs.

  7. Technique of Subnormothermic Ex Vivo Liver Perfusion for the Storage, Assessment, and Repair of Marginal Liver Grafts

    PubMed Central

    Goldaracena, Nicolas; Louis, Kristine S.; Selzner, Nazia; Selzner, Markus

    2014-01-01

    The success of liver transplantation has resulted in a dramatic organ shortage. In most transplant regions 20-30% of patients on the waiting list for liver transplantation die without receiving an organ transplant or are delisted for disease progression. One strategy to increase the donor pool is the utilization of marginal grafts, such as fatty livers, grafts from older donors, or donation after cardiac death (DCD). The current preservation technique of cold static storage is only poorly tolerated by marginal livers resulting in significant organ damage. In addition, cold static organ storage does not allow graft assessment or repair prior to transplantation. These shortcomings of cold static preservation have triggered an interest in warm perfused organ preservation to reduce cold ischemic injury, assess liver grafts during preservation, and explore the opportunity to repair marginal livers prior to transplantation. The optimal pressure and flow conditions, perfusion temperature, composition of the perfusion solution and the need for an oxygen carrier has been controversial in the past. In spite of promising results in several animal studies, the complexity and the costs have prevented a broader clinical application so far. Recently, with enhanced technology and a better understanding of liver physiology during ex vivo perfusion the outcome of warm liver perfusion has improved and consistently good results can be achieved. This paper will provide information about liver retrieval, storage techniques, and isolated liver perfusion in pigs. We will illustrate a) the requirements to ensure sufficient oxygen supply to the organ, b) technical considerations about the perfusion machine and the perfusion solution, and c) biochemical aspects of isolated organs. PMID:25145990

  8. AUGMENTATION OF LIMB PERFUSION AND REVERSAL OF TISSUE ISCHEMIA PRODUCED BY ULTRASOUND-MEDIATED MICROBUBBLE CAVITATION

    PubMed Central

    Belcik, J. Todd; Mott, Brian H.; Xie, Aris; Zhao, Yan; Kim, Sajeevani; Lindner, Nathan J.; Ammi, Azzdine; Linden, Joel M.; Lindner, Jonathan R.

    2015-01-01

    Background Ultrasound can increase tissue blood flow in part through the intravascular shear produced by oscillatory pressure fluctuations. We hypothesized that ultrasound-mediated increases in perfusion can be augmented by microbubble contrast agents that undergo ultrasound-mediated cavitation, and sought to characterize the biologic mediators. Methods and Results Contrast ultrasound perfusion imaging of hindlimb skeletal muscle and femoral artery diameter measurement were performed in non-ischemic mice after unilateral 10 min exposure to intermittent ultrasound alone (mechanical index [MI] 0.6 or 1.3) or ultrasound with lipid microbubbles (2×108 I.V.). Studies were also performed after inhibiting shear- or pressure-dependent vasodilator pathways, and in mice with hindlimb ischemia. Ultrasound alone produced a 2-fold increase (p<0.05) in muscle perfusion regardless of ultrasound power. Ultrasound-mediated augmentation in flow was greater with microbubbles (3-fold and 10-fold higher than control for MI 0.6 and 1.3, respectively; p<0.05), as was femoral artery dilation. Inhibition of endothelial nitric oxide synthase (eNOS) attenuated flow augmentation produced by ultrasound and microbubbles by 70% (p<0.01), whereas inhibition of adenosine-A2a receptors and epoxyeicosatrienoic acids had minimal effect. Limb nitric oxide (NO) production and muscle phospho-eNOS increased in a stepwise fashion by ultrasound and ultrasound with microbubbles. In mice with unilateral hindlimb ischemia (40–50% reduction in flow), ultrasound (MI 1.3) with microbubbles increased perfusion by 2-fold to a degree that was greater than the control non-ischemic limb. Conclusions Increases in muscle blood flow during high-power ultrasound are markedly amplified by the intravascular presence of microbubbles and can reverse tissue ischemia. These effects are most likely mediated by cavitation-related increases in shear and activation of eNOS. PMID:25834183

  9. Intestinal perfusion monitoring using photoplethysmography

    NASA Astrophysics Data System (ADS)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. Nance; Coté, Gerard L.

    2013-08-01

    In abdominal trauma patients, monitoring intestinal perfusion and oxygen consumption is essential during the resuscitation period. Photoplethysmography is an optical technique potentially capable of monitoring these changes in real time to provide the medical staff with a timely and quantitative measure of the adequacy of resuscitation. The challenges for using optical techniques in monitoring hemodynamics in intestinal tissue are discussed, and the solutions to these challenges are presented using a combination of Monte Carlo modeling and theoretical analysis of light propagation in tissue. In particular, it is shown that by using visible wavelengths (i.e., 470 and 525 nm), the perfusion signal is enhanced and the background contribution is decreased compared with using traditional near-infrared wavelengths leading to an order of magnitude enhancement in the signal-to-background ratio. It was further shown that, using the visible wavelengths, similar sensitivity to oxygenation changes could be obtained (over 50% compared with that of near-infrared wavelengths). This is mainly due to the increased contrast between tissue and blood in that spectral region and the confinement of the photons to the thickness of the small intestine. Moreover, the modeling results show that the source to detector separation should be limited to roughly 6 mm while using traditional near-infrared light, with a few centimeters source to detector separation leads to poor signal-to-background ratio. Finally, a visible wavelength system is tested in an in vivo porcine study, and the possibility of monitoring intestinal perfusion changes is showed.

  10. HYPERTENSIVE-ISCHEMIC LEG ULCERS

    PubMed Central

    Farber, Eugene M.; Schmidt, Otto E. L.

    1950-01-01

    Ischemic ulcers of the leg having characteristics different from those of ordinary leg ulcers have been observed in a small number of hypertensive patients, mostly women, during the past few years. Such ulcers are usually located above the ankle. They begin with a small area of purplish discoloration at the site of slight trauma, and progress to acutely tender ulceration. In studies of tissue removed from the margin and the base of an ulcer of this kind, obliterative arteriolar sclerotic changes, ischemic-appearing connective tissue and inflammatory changes were noted. Two additional cases are reported. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:15398887

  11. [Antioxidant therapy in ischemic stroke].

    PubMed

    Suslina, Z A; Federova, T N; Maksimova, M Iu; Riasina, T V; Stvolinskiĭ, S L; Khrapova, E V; Boldyrev, A A

    2000-01-01

    The paper presents the results of investigation of emoxipin, an antioxidant synthetic drug, for treatment of patients with ischemic disorders of cerebral circulation. The drug produced a beneficial clinical effect in patients with lacunar and cardioembolic strokes of moderate severity. Therapy with emoxipin increased endogenic antioxidant activity and improved a clinical status of the patients. The protective effect of carnosine was demonstrated in experimental acute hypobaric hypoxia and cerebral ischemia in rats. The results obtained permit to recommend an inclusion of both emoxipin and carnosine in a combined treatment of ischemic disorders of cerebral circulation.

  12. Tissue pertechnetate and iodinated contrast material ischemic stroke

    SciTech Connect

    Anderson, D.C.; Coss, D.T.; Jacobson, R.L.; Meyer, M.W.

    1980-11-01

    Isotope uptake during static radionuclide scanning and contrast enhancement during CT scanning, which may result from similar pathophysiologic mechanisms after ischemic infarction, were investigated in an animal model. Infarction was produced by transorbital occlusion of the middle cerebral artery in cats killed one, 2, 4, 8, or 16 days later. Sodium pertechnetate containing technetium-99m and 30% methylglucamine iothalamate labeled with I-125 were administered intravenously 60 and 15 min respectively prior to sacrifice. A coronal section through the infarct was parceled into 30 portions which were assayed for concentration of each isotope. Adjacent brain was prepared for histopathologic correlation. Concentrations of the 2 materials were highest in infarcted brain at 4 and 8 days. Strong positive correlation was found between tissue concentrations of the 2 materials in all brain samples. Elevated tissue levels correlated with necrosis, macrophage infiltration, and vascular hyperplasia. The results support the probability that radionuclide scan positivity and CT contrast enhancement reflect the same pathophysiologic development, probably extravasation of the respective labels, after schemic stroke.

  13. Ultrasound perfusion signal processing for tumor detection

    NASA Astrophysics Data System (ADS)

    Kim, MinWoo; Abbey, Craig K.; Insana, Michael F.

    2016-04-01

    Enhanced blood perfusion in a tissue mass is an indication of neo-vascularity and a sign of a potential malignancy. Ultrasonic pulsed-Doppler imaging is a preferred modality for noninvasive monitoring of blood flow. However, the weak blood echoes and disorganized slow flow make it difficult to detect perfusion using standard methods without the expense and risk of contrast enhancement. Our research measures the efficiency of conventional power-Doppler (PD) methods at discriminating flow states by comparing measurement performance to that of an ideal discriminator. ROC analysis applied to the experimental results shows that power Doppler methods are just 30-50 % efficient at perfusion flows less than 1ml/min, suggesting an opportunity to improve perfusion assessment through signal processing. A new perfusion estimator is proposed by extending the statistical discriminator approach. We show that 2-D perfusion color imaging may be enhanced using this approach.

  14. Changes in rest and exercise myocardial perfusion and left ventricular function 3 to 26 weeks after clinically uncomplicated acute myocardial infarction: effects of exercise training

    SciTech Connect

    Hung, J.; Gordon, E.P.; Houston, N.; Haskell, W.L.; Goris, M.L.; DeBusk, R.F.

    1984-11-01

    The effects of exercise training on exercise myocardial perfusion and left ventricular (LV) function in the first 6 months after clinically uncomplicated acute myocardial infarction (AMI) were assessed in 53 consecutive men aged 55 +/- 9 years. Symptom-limited treadmill exercise with thallium myocardial perfusion scintigraphy and symptom-limited upright bicycle ergometry with equilibrium gated radionuclide ventriculography were performed 3, 11 and 26 weeks after AMI by 23 men randomized to training and 30 randomized to no training. Peak cycle capacity increased in both groups between 3 and 26 weeks (p less than 0.01), but reached higher levels in trained than in untrained patients (803 +/- 149 vs 648 +/- 182 kg-m/min, p less than 0.01). Reversible thallium perfusion defects were significantly more frequent at 3 than at 26 weeks: 59% and 36% of patients, respectively (p less than 0.05), without significant inter-group differences. Values of LV ejection fraction at rest, submaximal and peak exercise did not change significantly in either group. The increase in functional capacity, i.e., peak treadmill or bicycle workload, that occurred 3 to 26 weeks after infarction was significantly correlated with the increase in peak exercise heart rate (p less than 0.001), but not with changes in myocardial perfusion or LV function determined by radionuclide techniques. Changes in myocardial perfusion or LV function do not appear to account for the improvement in peak functional capacity that occurs within the first 6 months after clinically uncomplicated AMI.

  15. Hysterosalpingo-radionuclide scintigraphy (HERS)

    SciTech Connect

    Iturralde, M.; Venter, P.F.

    1981-10-01

    A radionuclide procedure, hysterosalpingo-radionuclide scintigraphy (HERS), was designed to evaluate the migration of a particulate radioactive tracer from the vagina to the peritoneal cavity and ovaries as well as to image and functionally outline the patency of the pathways between these two extremes of the female reproductive system. Technetium-99m human albumin microspheres (99mTc-HAM) were deposited in the posterior fornices of patients who were divided into two specific groups. Group I consisted of patients who were to undergo different elective gynecologic operations, in which besides obtaining sequential images, radioactivity levels were measured in the removed organs and tissues. Group II consisted of patients referred by the Infertility Clinic for evaluation of their reproductive system pathways patency. In this latter group, HERS was compared with contrast hysterosalpingography (HSG) and peritoneoscopy (PCP). The results obtained from measurements of radioactivity levels on the removed surgical specimens and comparison with other conventional gynecologic diagnostic procedures provide accurate evidence of the migration of 99mTc-HAM from the vagina, through the uterus and tubes, to the peritoneal cavity and ovaries, and show that HERS is a simple noninvasive method for functionally imaging and assessing the patency of the female reproductive system pathways.

  16. Radionuclide transit in esophageal varices

    SciTech Connect

    Yeh, S.H.; Wang, S.J.; Wu, L.C.; Liu, R.S.; Tsai, Y.T.; Chiang, T.T.

    1985-05-01

    This study assessed esophageal motility in patients with esophageal varices by radionuclide transit studies. Data were acquired in list mode after an oral dose of 0.5 mCi Tc-99m sulfur colloid in 10 ml of water in the supine position above a low-energy all-purpose collimator of a gamma camera. The condensed image (CI) superimposed with a centroid curve was also produced in each case. Twenty-five normal subjects (N) and 32 patients (pts) with esophageal varices by endoscopy (large varices in Grades IV and V in 8 and small varices in Grade III or less in 24) were studied. TMTT, RTT, RF, and RI were all significantly increased in pts as compared to N. Especially, the transit time for the middle third (6.7 +- 2.6 sec vs 3.5 +- 0.9 sec in N, rho < 0.005) had the optimal sensitivy and specificity of 88% each at the cutoff value of 4.2 sec as determined by ROC analysis. In summary, radionuclide transit disorders occur in the majority of pts with esopageal varices. The middle RTT and CI are both optimal in sensitivity and specificity for detecting the abnormalities.

  17. Modeling Radionuclide Decay Chain Migration Using HYDROGEOCHEM

    NASA Astrophysics Data System (ADS)

    Lin, T. C.; Tsai, C. H.; Lai, K. H.; Chen, J. S.

    2014-12-01

    Nuclear technology has been employed for energy production for several decades. Although people receive many benefits from nuclear energy, there are inevitably environmental pollutions as well as human health threats posed by the radioactive materials releases from nuclear waste disposed in geological repositories or accidental releases of radionuclides from nuclear facilities. Theoretical studies have been undertaken to understand the transport of radionuclides in subsurface environments because that the radionuclide transport in groundwater is one of the main pathway in exposure scenarios for the intake of radionuclides. The radionuclide transport in groundwater can be predicted using analytical solution as well as numerical models. In this study, we simulate the transport of the radionuclide decay chain using HYDROGEOCHEM. The simulated results are verified against the analytical solution available in the literature. Excellent agreements between the numerical simulation and the analytical are observed for a wide spectrum of concentration. HYDROGECHEM is a useful tool assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

  18. Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease.

    PubMed

    Hidalgo, A; Pons-Lladó, G

    2015-01-01

    Cardiac magnetic resonance imaging (MRI) is an important tool that makes it possible to evaluate patients with cardiovascular disease; in addition to infarction and alterations in myocardial perfusion, cardiac MRI is useful for evaluating other phenomena such as microvascular obstruction and ischemia. The main prognostic factors in cardiac MRI are ventricular dysfunction, necrosis in late enhancement sequences, and ischemia in stress sequences. In acute myocardial infarction, cardiac MRI can evaluate the peri-infarct zone and quantify the size of the infarct. Furthermore, cardiac MRI's ability to detect and evaluate microvascular obstruction makes it a fundamental tool for establishing the prognosis of ischemic heart disease. In patients with chronic ischemic heart disease, cardiac MRI can detect ischemia induced by pharmacological stress and can diagnose infarcts that can be missed on other techniques.

  19. Radionuclide Releases During Normal Operations for Ventilated Tanks

    SciTech Connect

    Blunt, B.

    2001-09-24

    This calculation estimates the design emissions of radionuclides from Ventilated Tanks used by various facilities. The calculation includes emissions due to processing and storage of radionuclide material.

  20. Sensors and Automated Analyzers for Radionuclides

    SciTech Connect

    Grate, Jay W.; Egorov, Oleg B.

    2003-03-27

    The production of nuclear weapons materials has generated large quantities of nuclear waste and significant environmental contamination. We have developed new, rapid, automated methods for determination of radionuclides using sequential injection methodologies to automate extraction chromatographic separations, with on-line flow-through scintillation counting for real time detection. This work has progressed in two main areas: radionuclide sensors for water monitoring and automated radiochemical analyzers for monitoring nuclear waste processing operations. Radionuclide sensors have been developed that collect and concentrate radionuclides in preconcentrating minicolumns with dual functionality: chemical selectivity for radionuclide capture and scintillation for signal output. These sensors can detect pertechnetate to below regulatory levels and have been engineered into a prototype for field testing. A fully automated process monitor has been developed for total technetium in nuclear waste streams. This instrument performs sample acidification, speciation adjustment, separation and detection in fifteen minutes or less.

  1. Detecting low levels of radionuclides in fluids

    DOEpatents

    Patch, Keith D.; Morgan, Dean T.

    2000-01-01

    An apparatus and method for detecting low levels of one or more radionuclides in a fluid sample uses a substrate that includes an ion exchange resin or other sorbent material to collect the radionuclides. A collecting apparatus includes a collecting chamber that exposes the substrate to a measured amount of the fluid sample such that radionuclides in the fluid sample are collected by the ion exchange resin. A drying apparatus, which can include a drying chamber, then dries the substrate. A measuring apparatus measures emissions from radionuclides collected on the substrate. The substrate is positioned in a measuring chamber proximate to a detector, which provides a signal in response to emissions from the radionuclides. Other analysis methods can be used to detect non-radioactive analytes, which can be collected with other types of sorbent materials.

  2. Therapeutic angiogenesis in ischemic muscles after local injection of fragmented fibers with loaded traditional Chinese medicine

    NASA Astrophysics Data System (ADS)

    Li, Huiyan; Wan, Huiying; Xia, Tian; Chen, Maohua; Zhang, Yun; Luo, Xiaoming; Li, Xiaohong

    2015-07-01

    Therapeutic angiogenesis remains the most effective method to re-establish a proper blood flow in ischemic tissues. There is a great clinical need to identify an injectable format to achieve a well accumulation following local administration and a sustained delivery of biological factors at the ischemic sites. In the current study, fragmented nanofibers with loaded traditional Chinese medicines, astragaloside IV (AT), the main active ingredient of astragalus, and ferulic acid (FA), the main ingredient of angelica, were proposed to promote the microvessel formation after intramuscular injection into ischemic hindlimbs. Fragmented fibers with average lengths of 5 (FF-5), 20 (FF-20) and 80 μm (FF-80) were constructed by the cryocutting of aligned electrospun fibers. Their dispersion in sodium alginate solution (0.2%) indicated good injectability. After injection into the quadriceps muscles of the hindlimbs, FF-20 and FF-80 fiber fragments showed higher tissue retentions than FF-5, and around 90% of the injected doses were determined after 7 days. On a hindlimb ischemia model established by ligating the femoral arteries, intramuscular injection of the mixtures of FA-loaded and AT-loaded FF-20 fiber fragments substantially reduced the muscle degeneration with minimal fibrosis formation, significantly enhanced the neovessel formation and hindlimb perfusion in the ischemic tissues, and efficiently promoted the limb salvage with few limb losses. Along with the easy manipulation and lower invasiveness for in vivo administration, fragmented fibers should become potential drug carriers for disease treatment, wound recovery and tissue repair after local injection.

  3. Simplified Correction of Ischemic Index in Diabetic Retinopathy Evaluated by Ultra-widefield Fluorescein Angiography

    PubMed Central

    Kim, Jeong Hee; Jung, Hyeong-Gi; Chung, Hye Jin; Lee, Kyungmin

    2015-01-01

    Purpose To develop a novel, simplified method for correcting the ischemic index of nonperfused areas in diabetic retinopathy (DR). Methods We performed a retrospective review of 103 eyes with naive DR that underwent ultra-widefield angiography (UWFA) over a year. UWFAs were graded according to the quantity of retinal non-perfusion, and uncorrected ischemic index (UII) and corrected ischemic index (CII) were calculated using a simplified, novel method. Results The average differences between UII and CII in the non-proliferative DR group and the proliferative DR group were 0.7 ± 0.9% in the <25% CII group, 3.0 ± 0.9% in the 25% to 49.9% CII group, and 3.6 ± 0.6% in the >50% CII group, respectively. A CII >25% was critical for determining DR progression (p < 0.001). Conclusions Distortion created by UWFA needs to be corrected because the difference between UII and CII in DR increases with the ischemic index. PMID:26028944

  4. Angiogenesis effect of therapeutic ultrasound on ischemic hind limb in mice

    PubMed Central

    Huang, Jing-Juan; Shi, Yi-Qin; Li, Rui-Lin; Hu, An; Zhou, Hong-Sheng; Cheng, Qian; Xu, Zheng; Yang, Zhi-Ming; Hao, Chang-Ning; Duan, Jun-Li

    2014-01-01

    Although significant progress in bypass surgery and catheter intervention against peripheral artery disease, the number of severe critical limb ischemia (CLI) patients is increasing. Thus, it is crucial to develop new, non-invasive therapeutic strategies. The purpose of this study was to determine the mechanism of therapeutic ultrasound (TUS) on ischemic angiogenesis using mouse model of hindlimb ischemia and the cellular/molecular mechanisms underlying TUS-related neovascularization. The hindlimb ischemic mice were exposed to extracorporeal TUS for 3, 6, 9 minute per day (1 MHz, 0.3 W/cm2) until day 14 after left femoral artery ligation. Increased blood perfusion and capillary density were determined following 9 min of TUS compared with ischemic group. Moreover, TUS treatment increased the protein levels of vascular endothelial growth factor (VEGF), hypoxic inducible factor-1α (HIF-1α), endothelial nitric oxide synthase (eNOS) and p-Akt in vivo. TUS promoted capillary-like tube formation, migration and motility of human umbilical venous endothelial cells (HUVECs). Furthermore, the protein expressions of VEGF, eNOS and p-Akt were increased after TUS treatment. In conclusion, TUS therapy promotes postnatal neovascularization through multiple angiogenic pathways in mice model of ischemic hindlimb. PMID:25628781

  5. Pediatric cerebral stroke: susceptibility-weighted imaging may predict post-ischemic malignant edema.

    PubMed

    Bosemani, Thangamadhan; Poretti, Andrea; Orman, Gunes; Meoded, Avner; Huisman, Thierry A G M

    2013-10-01

    Susceptibility-weighted imaging (SWI) is an advanced MRI technique providing information on the blood oxygenation level. Deoxyhemoglobin is increased in hypoperfused tissue characterized by SWI-hypointensity, while high oxyhemoglobin concentration within hyperperfused tissue results in a SWI iso- or hyperintensity compared to healthy brain tissue. We describe a child with a stroke, where SWI in addition to excluding hemorrhage and delineating the thrombus proved invaluable in determining regions of hyperperfusion or luxury perfusion, which contributed further to the prognosis including an increased risk of developing post-ischemic malignant edema.

  6. Pediatric Cerebral Stroke: Susceptibility-Weighted Imaging May Predict Post-Ischemic Malignant Edema

    PubMed Central

    Bosemani, Thangamadhan; Poretti, Andrea; Orman, Gunes; Meoded, Avner; Huisman, Thierry A.G.M.

    2013-01-01

    Summary Susceptibility-weighted imaging (SWI) is an advanced MRI technique providing information on the blood oxygenation level. Deoxyhemoglobin is increased in hypoperfused tissue characterized by SWI-hypointensity, while high oxyhemoglobin concentration within hyperperfused tissue results in a SWI iso- or hyperintensity compared to healthy brain tissue. We describe a child with a stroke, where SWI in addition to excluding hemorrhage and delineating the thrombus proved invaluable in determining regions of hyperperfusion or luxury perfusion, which contributed further to the prognosis including an increased risk of developing post-ischemic malignant edema. PMID:24199819

  7. Retrograde coronary sinus versus aortic root perfusion with cold cardioplegia: randomized study of levels of cardiac enzymes in 40 patients

    SciTech Connect

    Guiraudon, G.M.; Campbell, C.S.; McLellan, D.G.; Kostuk, W.J.; Purves, P.D.; MacDonald, J.L.; Cleland, A.G.; Tadros, N.B.

    1986-11-01

    Myocardial injury was assessed with the use of enzyme indexes in 40 patients randomly assigned to one of two groups undergoing coronary artery bypass surgery. Twenty patients received cold cardioplegia delivered by retrograde coronary sinus perfusion and 20 received cardioplegic solution by anterograde aortic root perfusion. Creatine kinase isoenzyme MB and lactate dehydrogenese isoenzyme 1 and isoenzyme 2 assays were carried out on blood samples obtained from the coronary sinus before aortic cross-clamping and 0, 5, and 30 min after aortic unclamping. Levels of these enzymes were also obtained from venous blood samples before aortic cross-clamping and 3, 8, 14, and 20 hr after aortic unclamping and 2, 3, 4, and 5 days after surgery. Preoperative and postoperative hemodynamic measurements (Swan-Ganz catheter) and radionuclide wall motion studies were also obtained for comparison. There was no overall significant difference between the two groups postoperatively in terms of enzyme indexes, hemodynamic measurements, or results of wall motion studies. We conclude that retrograde coronary sinus perfusion is an alternative to aortic root perfusion in delivering cold cardioplegia. More studies are required to determine which subgroup of patients with coronary artery disease may benefit from retrograde coronary perfusion.

  8. Computational methods in radionuclide dosimetry

    NASA Astrophysics Data System (ADS)

    Bardiès, M.; Myers, M. J.

    1996-10-01

    The various approaches in radionuclide dosimetry depend on the size and spatial relation of the sources and targets considered in conjunction with the emission range of the radionuclide used. We present some of the frequently reported computational techniques on the basis of the source/target size. For whole organs, or for sources or targets bigger than some centimetres, the acknowledged standard was introduced 30 years ago by the MIRD committee and is still being updated. That approach, based on the absorbed fraction concept, is mainly used for radioprotection purposes but has been updated to take into account the dosimetric challenge raised by therapeutic use of vectored radiopharmaceuticals. At this level, the most important computational effort is in the field of photon dosimetry. On the millimetre scale, photons can often be disregarded, and or electron dosimetry is generally reported. Heterogeneities at this level are mainly above the cell level, involving groups of cell or a part of an organ. The dose distribution pattern is often calculated by generalizing a point source dose distribution, but direct calculation by Monte Carlo techniques is also frequently reported because it allows media of inhomogeneous density to be considered. At the cell level, and electron (low-range or Auger) are the predominant emissions examined. Heterogeneities in the dose distribution are taken into account, mainly to determine the mean dose at the nucleus. At the DNA level, Auger electrons or -particles are considered from a microdosimetric point of view. These studies are often connected with radiobiological experiments on radionuclide toxicity.

  9. Drift-Scale Radionuclide Transport

    SciTech Connect

    P.R. Dixon

    2004-02-17

    The purpose of this Model Report is to document two models for drift-scale radionuclide transport. This has been developed in accordance with ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]), which includes planning documents for the technical work scope, content, and management of this Model Report in Section 1.15, Work Package AUZM11, ''Drift-Scale Radionuclide Transport.'' The technical work scope for this Model Report calls for development of a process-level model and an abstraction model representing diffusive release from the invert to the rocks, partitioned between fracture and matrix, as compared to the fracture-release approach used in the Site Recommendation. The invert is the structure constructed in a drift to provide the floor of that drift. The plan for validation of the models documented in this Model Report is given in Section I-5 of Attachment I in BSC (2002 [160819]). Note that the model validation presented in Section 7 deviates from the technical work plan (BSC 2002 [160819], Section I-5) in that an independent technical review specifically for model validation has not been conducted, nor publication in a peer-reviewed journal. Model validation presented in Section 7 is based on corroboration with alternative mathematical models, which is also called out by the technical work plan (BSC 2002 [160819], Section I-5), and is sufficient based on the requirements of AP-SIII.10Q for model validation. See Section 7 for additional discussion. The phenomenon of flow and transport in the vicinity of the waste emplacement drift are evaluated in this model report under ambient thermal, chemical, and mechanical conditions. This includes the effects of water diversion around an emplacement drift and the flow and transport behavior expected in a fractured rock below the drift. The reason for a separate assessment of drift-scale transport is that the effects of waste emplacement drifts on flow

  10. Transverse section radionuclide scanning system

    DOEpatents

    Kuhl, David E.; Edwards, Roy Q.

    1976-01-01

    This invention provides a transverse section radionuclide scanning system for high-sensitivity quantification of brain radioactivity in cross-section picture format in order to permit accurate assessment of regional brain function localized in three-dimensions. High sensitivity crucially depends on overcoming the heretofore known raster type scanning, which requires back and forth detector movement involving dead-time or partial enclosure of the scan field. Accordingly, this invention provides a detector array having no back and forth movement by interlaced detectors that enclose the scan field and rotate as an integral unit around one axis of rotation in a slip ring that continuously transmits the detector data by means of laser emitting diodes, with the advantages that increased amounts of data can be continuously collected, processed and displayed with increased sensitivity according to a suitable computer program.

  11. Cosmogenic radionuclides in stone meteorites

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    This document presents the techniques and compilation of results of cosmogenic Al-26 measurements at Goddard Space Flight Center on 91 samples of 76 stone meteorites. Short-lived radionuclides, including Na-22, Sc-46, Mn-54, and Co-60, were measured in 13 of these meteorites. About one-third of these data has not previously been published. The results are discussed briefly in terms of (1) depletion of Al-26 and natural potassium due to weathering, (2) possible exposure of several chondrites to an unusually high cosmic-ray flux, (3) comparison of Al-26, Na-22, Sc-46, and Mn5-54 in chondrites with the spallation Ne-22/Ne-21 ratio as a shielding indicator, and (4) comparison of (Al-26)-(Ne-22)/Ne-21 data for achondrite classes with the chondrite trend.

  12. Radionuclides in surface and groundwater

    USGS Publications Warehouse

    Campbell, Kate M.

    2009-01-01

    Unique among all the contaminants that adversely affect surface and water quality, radioactive compounds pose a double threat from both toxicity and damaging radiation. The extreme energy potential of many of these materials makes them both useful and toxic. The unique properties of radioactive materials make them invaluable for medical, weapons, and energy applications. However, mining, production, use, and disposal of these compounds provide potential pathways for their release into the environment, posing a risk to both humans and wildlife. This chapter discusses the sources, uses, and regulation of radioactive compounds in the United States, biogeochemical processes that control mobility in the environment, examples of radionuclide contamination, and current work related to contaminated site remediation.

  13. Illicit Trafficking of Natural Radionuclides

    NASA Astrophysics Data System (ADS)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  14. Illicit Trafficking of Natural Radionuclides

    SciTech Connect

    Friedrich, Steinhaeusler; Lyudmila, Zaitseva

    2008-08-07

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  15. Non-Invasive Respiratory Impedance Enhances Cerebral Perfusion in Healthy Adults

    PubMed Central

    Favilla, Christopher G.; Parthasarathy, Ashwin B.; Detre, John A.; Yodh, Arjun G.; Mullen, Michael T.; Kasner, Scott E.; Gannon, Kimberly; Messé, Steven R.

    2017-01-01

    Optimization of cerebral blood flow (CBF) is the cornerstone of clinical management in a number of neurologic diseases, most notably ischemic stroke. Intrathoracic pressure influences cardiac output and has the potential to impact CBF. Here, we aim to quantify cerebral hemodynamic changes in response to increased respiratory impedance (RI) using a non-invasive respiratory device. We measured cerebral perfusion under varying levels of RI (6 cm H2O, 9 cm H2O, and 12 cm H2O) in 20 healthy volunteers. Simultaneous measurements of microvascular CBF and middle cerebral artery mean flow velocity (MFV), respectively, were performed with optical diffuse correlation spectroscopy and transcranial Doppler ultrasound. At a high level of RI, MFV increased by 6.4% compared to baseline (p = 0.004), but changes in cortical CBF were non-significant. In a multivariable linear regression model accounting for end-tidal CO2, RI was associated with increases in both MFV (coefficient: 0.49, p < 0.001) and cortical CBF (coefficient: 0.13, p < 0.001), although the magnitude of the effect was small. Manipulating intrathoracic pressure via non-invasive RI was well tolerated and produced a small but measurable increase in cerebral perfusion in healthy individuals. Future studies in acute ischemic stroke patients with impaired cerebral autoregulation are warranted in order to assess whether RI is feasible as a novel non-invasive therapy for stroke. PMID:28261153

  16. Sanguineous normothermic machine perfusion improves hemodynamics and biliary epithelial regeneration in DCD porcine livers

    PubMed Central

    Liu, Qiang; Nassar, Ahmed; Farias, Kevin; Buccini, Laura; Baldwin, William; Mangino, Martin; Bennett, Ana; O'Rourke, Colin; Okamoto, Toshiro; Uso, Teresa Diago; Fung, John; Abu-Elmagd, Kareem; Miller, Charles; Quintini, Cristiano

    2014-01-01

    The effect of normothermic machine perfusion (NMP) on post-reperfusion hemodynamics and extrahepatic biliary duct histology of donors after cardiac death (DCD) livers after transplantation has not been addressed thoroughly and represented the object of this study. Ten livers (n=5/group) with 60’ of warm ischemia were preserved by cold storage (CS) or sanguineous NMP for 10 hours, and then reperfused for 24 hours with whole blood in an isolated perfusion system to simulate transplantation. In our experiment, arterial and portal venous flows were stable in NMP group during the entire simulated reperfusion, while decreased dramatically in CS group after 16 hours post-reperfusion (P<.05), findings consistent with severe parenchymal injury. Similarly, significant differences existed between CS and NMP group on hepatocellular enzyme release, bile volume produced, and enzyme released into bile (P<.05). On histology CS livers presented with diffuse hepatocyte congestion, necrosis, intraparenchymal hemorrhage, denudated biliary epithelium and submucosal bile duct necrosis, while NMP liver showed very mild injury in liver parenchyma and biliary architecture. Most importantly, Ki67 staining in extrahepatic bile duct showed biliary epithelial regeneration. Our findings advance the knowledge of post-reperfusion events that characterize DCD livers and propose NMP as a beneficial preservation modality able to improve biliary regeneration after a major ischemic event, which may prevent in clinical transplantation the development of ischemic cholangiopathy. PMID:24805852

  17. Determination of skeletal muscle perfusion using arterial spin labeling NMRI: validation by comparison with venous occlusion plethysmography.

    PubMed

    Raynaud, J S; Duteil, S; Vaughan, J T; Hennel, F; Wary, C; Leroy-Willig, A; Carlier, P G

    2001-08-01

    T(1)-based determination of perfusion was performed with the high temporal and spatial resolution that monitoring of exercise physiology requires. As no data were available on the validation of this approach in human muscles, T(1)-based NMRI of perfusion was compared to standard strain-gauge venous occlusion plethysmography performed simultaneously within a 4 T magnet. Two different situations were investigated in 21 healthy young volunteers: 1) a 5-min ischemia of the leg, or 2) a 2-3 min ischemic exercise consisting of a plantar flexion on an amagnetic ergometer. Leg perfusion was monitored over 5-15 min of the recovery phase, after the air-cuff arterial occlusion had been released. The interesting features of the sequence were the use of a saturation-recovery module for the introduction of a T(1) modulation and of single-shot spin echo for imaging. Spatial resolution was 1.7 x 2.0 mm and temporal resolution was 2 s. For data analysis, ROIs were traced on different muscles and perfusion was calculated from the differences in muscle signal intensity in successive images. To allow comparison with the global measurement of perfusion by plethysmography, the T(1)-based NMR measurements in exercising muscles were rescaled to the leg cross-section. The perfusion measurements obtained by plethysmography and NMRI were in close agreement with a correlation coefficient between 0.87 and 0.92. This indicates that pulsed arterial techniques provide determination of muscle perfusion not only with superior spatial and temporal resolution but also with exactitude.

  18. The effect of Ligustrum delavayanum on isolated perfused rat heart

    PubMed Central

    Stankovičová, Tatiana; Frýdl, Miroslav; Kubicová, Mária; Baróniková, Slávka; Nagy, Milan; Grančai, Daniel; Švec, Pavel

    2001-01-01

    BACKGROUND: Extract of ligustrum leaves (Ligustrum delavayanum Hariot [Oleaceae]) is well known in traditional Chinese medicine. One of the active components, oleuropein, displays vasodilating and hypotensive effects. OBJECTIVE: To analyze the effect of 0.008% lyophilized extract of ligustrum dissolved in 0.5% ethanol on heart function. ANIMALS AND METHODS: Experiments were done on isolated rat hearts perfused by the Langendorff method in control conditions and during ischemic-reperfusion injury. RESULTS: Application of ligustrum induced positive inotropic and vasodilating effects in spontaneously beating hearts. Pretreatment of the hearts with ligustrum reduced left ventricular diastolic pressure measured during reperfusion and improved left ventricular contraction compared with hearts without any pretreatment. Ligustrum significantly suppressed the incidence and duration of cardiac reperfusion arrhythmias, expressed as G-score, from 7.40±0.58 in nontreated rats to 1.97±0.50. DISCUSSION: Application of ligustrum or ethanol alone induced changes in coordination between atria and ventricles during ischemia-reperfusion injury. The ‘g-score’, a new parameter summing the incidence and duration of atrioventricular blocks, atrioventricular dissociation and cardiac arrest, is introduced. The g-scores with ligustrum pretreatment were higher during ischemia than during reperfusion. Ethanol significantly depressed myocardial contractility and coronary flow, and nonsignificantly decreased heart rate of isolated rat hearts. Electrical changes observed during coronary reperfusion in the presence of ethanol were accompanied by deterioration of contractile function. CONCLUSIONS: Ligustrum had a significant protective effect on rat myocardium against ischemic-reperfusion injury. Ethanol partially attenuated the protective effect of ligustrum. PMID:20428448

  19. Technetium myocardial perfusion agents: an introduction

    SciTech Connect

    English, R.J.; Kozlowski, J.; Tumeh, S.S.; Holman, B.L.

    1987-09-01

    This is the third in a series of four Continuing Education articles on developing radiopharmaceuticals. After reading this article, the reader should be able to: 1) understand the basic concepts of myocardial perfusion imaging; and 2) discuss the advantages of the technetium myocardial perfusion complexes over thallium-201.

  20. Long term perfusion system supporting adipogenesis

    PubMed Central

    Abbott, Rosalyn D.; Raja, Waseem K.; Wang, Rebecca Y.; Stinson, Jordan A.; Glettig, Dean L.; Burke, Kelly A.; Kaplan, David L.

    2015-01-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogensis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  1. Using Flat-Panel Perfusion Imaging to Measure Cerebral Hemodynamics

    PubMed Central

    Lin, Chung-Jung; Guo, Wan-Yuo; Chang, Feng-Chi; Hung, Sheng-Che; Chen, Ko-Kung; Yu, Deuerling-Zheng; Wu, Chun-Hsien Frank; Liou, Jy-Kang Adrian

    2016-01-01

    Abstract Flat-detector CT perfusion (FD-CTP) imaging has demonstrated efficacy in qualitatively accessing the penumbra in acute stroke equivalent to that of magnetic resonance perfusion (MRP). The aim of our study was to evaluate the feasibility of quantifying oligemia in the brain in patients with carotid stenosis. Ten patients with unilateral carotid stenosis of >70% were included. All MRPs and FD-CTPs were performed before stenting. Region-of-interests (ROIs) including middle cerebral artery territory at basal ganglia level on both stenotic and contralateral sides were used for quantitative analysis. Relative time to peak (rTTP) was defined as TTP of the stenotic side divided by TTP of the contralateral side, and so as relative cerebral blood volume (rCBV), relative mean transit time (rMTT), and relative cerebral blood flow (rCBF). Absolute and relative TTP, CBV, MTT, CBF between two modalities were compared. For absolute quantitative analysis, the correlation of TTP was highest (r = 0.56), followed by CBV (r = 0.47), MTT (r = 0.47), and CBF (r = 0.43); for relative quantitative analysis, rCBF was the highest (r = 0.79), followed by rTTP (r = 0.75) and rCBV (r = 0.50). We confirmed that relative quantitative assessment of FD-CTP is feasible in chronic ischemic disease. Absolute quantitative measurements between MRP and FD-CTP only expressed moderate correlations. Optimization of acquisitions and algorithms is warranted to achieve better quantification. PMID:27196456

  2. Bayesian SPECT lung imaging for visualization and quantification of pulmonary perfusion

    SciTech Connect

    Scarfone, C.; Jaszczak, R.J.; Gilland, D.R.; Greer, K.L.; Munley, M.T.; Marks, L.B.; Coleman, R.E.

    1998-12-01

    In this paper, the authors quantitatively and qualitatively examine the use of a Gibbs prior in maximum a posteriori (MAP) reconstruction of SPECT images of pulmonary perfusion using the expectation-maximization (EM) algorithm. This Bayesian approach is applied to SPECT projection data acquired from a realistic torso phantom with spherical defects in the lungs simulating perfusion deficits. Both the scatter subtraction constant (k) and the smoothing parameter beta ({beta}) characterizing the prior are varied to study their effect on image quality and quantification. Region of interest (ROI) analysis is used to compare MAP-EM radionuclide concentration estimates with those derived from a ``clinical`` implementation of filtered backprojection (CFBP), and a quantitative implementation of FBP (QFBP) utilizing nonuniform attenuation and scatter compensation. Qualitatively, the MAP-EM images contain reduced artifacts near the lung boundaries relative to the FBP implementations. Generally, the MAP-EM image`s visual quality and the ability to discern the areas of reduced radionuclide concentration in the lungs depend on the value of {beta} and the total number of iterations. For certain choices of {beta} and total iterations, MAP-EM lung images are visually comparable to FBP. Based on profile and ROI analysis, SPECT QFBP and MAP-EM images have the potential to provide quantitatively accurate reconstructions when compared to CFBP. The computational burden, however, is greater for the MAP-EM approach. To demonstrate the clinical efficacy of the methods, the authors present pulmonary images of a patient with lung cancer.

  3. Radionuclides: Accumulation and Transport in Plants.

    PubMed

    Gupta, D K; Chatterjee, S; Datta, S; Voronina, A V; Walther, C

    Application of radioactive elements or radionuclides for anthropogenic use is a widespread phenomenon nowadays. Radionuclides undergo radioactive decays releasing ionizing radiation like gamma ray(s) and/or alpha or beta particles that can displace electrons in the living matter (like in DNA) and disturb its function. Radionuclides are highly hazardous pollutants of considerable impact on the environment, food chain and human health. Cleaning up of the contaminated environment through plants is a promising technology where the rhizosphere may play an important role. Plants belonging to the families of Brassicaceae, Papilionaceae, Caryophyllaceae, Poaceae, and Asteraceae are most important in this respect and offer the largest potential for heavy metal phytoremediation. Plants like Lactuca sativa L., Silybum marianum Gaertn., Centaurea cyanus L., Carthamus tinctorius L., Helianthus annuus and H. tuberosus are also important plants for heavy metal phytoremediation. However, transfer factors (TF) of radionuclide from soil/water to plant ([Radionuclide]plant/[Radionuclide]soil) vary widely in different plants. Rhizosphere, rhizobacteria and varied metal transporters like NRAMP, ZIP families CDF, ATPases (HMAs) family like P1B-ATPases, are involved in the radio-phytoremediation processes. This review will discuss recent advancements and potential application of plants for radionuclide removal from the environment.

  4. Myocardial perfusion with rubidium-82. III. Theory relating severity of coronary stenosis to perfusion deficit

    SciTech Connect

    Mullani, N.A.

    1984-11-01

    The relation between the quantitative perfusion deficit, as measured by emission computerized tomography, and the severity of coronary artery stenosis is important for the noninvasive clinical evaluation of coronary artery disease in man. Positron emission tomography allows direct noninvasive measurement of myocardial perfusion and quantification of the size of the perfusion defect. Given this important imformation, a mathematical model has been derived to gauge the severity of a coronary stenosis from quantitative perfusion measurements in the normal and poststenotic regions of the heart. The theoretical basis is presented for relating regional myocardial perfusion and regional perfusion resistance to total, coronary blood flow and resistance at normal resting flow and during maximal coronary vasodilation. The concept of perfusion reserve is presented as a clinical measure of the severity of a stenosis.

  5. Ischemic preconditioning enhances integrity of coronary endothelial tight junctions

    SciTech Connect

    Li, Zhao; Jin, Zhu-Qiu

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Cardiac tight junctions are present between coronary endothelial cells. Black-Right-Pointing-Pointer Ischemic preconditioning preserves the structural and functional integrity of tight junctions. Black-Right-Pointing-Pointer Myocardial edema is prevented in hearts subjected to ischemic preconditioning. Black-Right-Pointing-Pointer Ischemic preconditioning enhances translocation of ZO-2 from cytosol to cytoskeleton. -- Abstract: Ischemic preconditioning (IPC) is one of the most effective procedures known to protect hearts against ischemia/reperfusion (IR) injury. Tight junction (TJ) barriers occur between coronary endothelial cells. TJs provide barrier function to maintain the homeostasis of the inner environment of tissues. However, the effect of IPC on the structure and function of cardiac TJs remains unknown. We tested the hypothesis that myocardial IR injury ruptures the structure of TJs and impairs endothelial permeability whereas IPC preserves the structural and functional integrity of TJs in the blood-heart barrier. Langendorff hearts from C57BL/6J mice were prepared and perfused with Krebs-Henseleit buffer. Cardiac function, creatine kinase release, and myocardial edema were measured. Cardiac TJ function was evaluated by measuring Evans blue-conjugated albumin (EBA) content in the extravascular compartment of hearts. Expression and translocation of zonula occludens (ZO)-2 in IR and IPC hearts were detected with Western blot. A subset of hearts was processed for the observation of ultra-structure of cardiac TJs with transmission electron microscopy. There were clear TJs between coronary endothelial cells of mouse hearts. IR caused the collapse of TJs whereas IPC sustained the structure of TJs. IR increased extravascular EBA content in the heart and myocardial edema but decreased the expression of ZO-2 in the cytoskeleton. IPC maintained the structure of TJs. Cardiac EBA content and edema were reduced in IPC hearts. IPC

  6. Arterial ischemic stroke in HIV

    PubMed Central

    Bryer, Alan; Lucas, Sebastian; Stanley, Alan; Allain, Theresa J.; Joekes, Elizabeth; Emsley, Hedley; Turnbull, Ian; Downey, Colin; Toh, Cheng-Hock; Brown, Kevin; Brown, David; Ison, Catherine; Smith, Colin; Corbett, Elizabeth L.; Nath, Avindra; Heyderman, Robert S.; Connor, Myles D.; Solomon, Tom

    2016-01-01

    HIV infection, and potentially its treatment, increases the risk of an arterial ischemic stroke. Multiple etiologies and lack of clear case definitions inhibit progress in this field. Several etiologies, many treatable, are relevant to HIV-related stroke. To fully understand the mechanisms and the terminology used, a robust classification algorithm to help ascribe the various etiologies is needed. This consensus paper considers the strengths and limitations of current case definitions in the context of HIV infection. The case definitions for the major etiologies in HIV-related strokes were refined (e.g., varicella zoster vasculopathy and antiphospholipid syndrome) and in some instances new case definitions were described (e.g., HIV-associated vasculopathy). These case definitions provided a framework for an algorithm to help assign a final diagnosis, and help classify the subtypes of HIV etiology in ischemic stroke. PMID:27386505

  7. [Compromized myocardial perfusion in arrhythmias (author's transl)].

    PubMed

    Simon, H; Neumann, G; Felix, R; Hedde, H; Schaede, A; Thurn, P; Winkler, C

    1977-09-15

    In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

  8. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR  <  0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR ≈ 0.65, the anterior-to-lateral flow ratio was 0.29  ±  0.01, over-estimating stenosis severity as compared to 0.42  ±  0.01 (p  <  0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50  ±  0.04 falsely indicating an actionable ischemic condition in a healthy

  9. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system.

    PubMed

    Fahmi, Rachid; Eck, Brendan L; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G; Wilson, David L

    2016-03-21

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR < 0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR ≈ 0.65, the anterior-to-lateral flow ratio was 0.29 ± 0.01, over-estimating stenosis severity as compared to 0.42 ± 0.01 (p < 0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50 ± 0.04 falsely indicating an actionable ischemic condition in a healthy territory. This ratio was 1.00 ± 0.08 at 70 ke

  10. 2008 LANL radionuclide air emissions report

    SciTech Connect

    Fuehne, David P.

    2009-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2008. This report meets the reporting requirements established in the regulations.

  11. 2009 LANL radionuclide air emissions report

    SciTech Connect

    Fuehne, David P.

    2010-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2009. This report meets the reporting requirements established in the regulations.

  12. 2010 LANL radionuclide air emissions report /

    SciTech Connect

    Fuehne, David P.

    2011-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2010. This report meets the reporting requirements established in the regulations.

  13. Renalase protects against ischemic AKI.

    PubMed

    Lee, H Thomas; Kim, Joo Yun; Kim, Mihwa; Wang, Peili; Tang, Lieqi; Baroni, Sara; D'Agati, Vivette D; Desir, Gary V

    2013-02-01

    Elevated levels of plasma catecholamines accompany ischemic AKI, possibly contributing the inflammatory response. Renalase, an amine oxidase secreted by the proximal tubule, degrades circulating catecholamines and reduces myocardial necrosis, suggesting that it may protect against renal ischemia reperfusion injury. Here, mice subjected to renal ischemia reperfusion injury had significantly lower levels of renalase in the plasma and kidney compared with sham-operated mice. Consistent with this, plasma NE levels increased significantly after renal ischemia reperfusion injury. Furthermore, renal tubular inflammation, necrosis, and apoptosis were more severe and plasma catecholamine levels were higher in renalase-deficient mice subjected to renal ischemia reperfusion compared with wild-type mice. Administration of recombinant human renalase reduced plasma catecholamine levels and ameliorated ischemic AKI in wild-type mice. Taken together, these data suggest that renalase protects against ischemic AKI by reducing renal tubular necrosis, apoptosis, and inflammation, and that plasma renalase might be a biomarker for AKI. Recombinant renalase therapy may have potential for the prevention and treatment of AKI.

  14. Noninvasive assessment of right ventricular function: will there be resurgence in radionuclide imaging techniques?

    PubMed

    Ramani, Gautam V; Gurm, Gagandeep; Dilsizian, Vasken; Park, Myung H

    2010-03-01

    Right ventricular (RV) function is increasingly being recognized as an important prognostic marker in multiple cardiopulmonary disease states, including congestive heart failure, pulmonary arterial hypertension, and chronic obstructive pulmonary disease. Accurate and reproducible measures of RV function, although technically challenging, are highly relevant in the clinical setting. Radionuclide techniques (eg, first-pass radionuclide angiography for quantifying RV systolic function) were developed nearly 40 years ago. More recently, MRI and transthoracic echocardiography have become the diagnostic imaging techniques of choice for the noninvasive evaluation of RV function. However, developments in single photon emission computed tomography (SPECT), positron emission tomography (PET), and hybrid SPECT/CT and PET/CT systems have greatly improved the image quality and contrast resolution of radionuclide imaging of the heart, allowing for coregistered physiologic and anatomical information of the right ventricle in three dimensions. These improvements in cardiac imaging provide new opportunities for assessing RV myocardial perfusion, function, and anatomy in the same setting. Such imaging approaches may in the future provide assistance with proactive disease management, including early diagnosis of impending RV dysfunction in high-risk patients and for guiding decisions to initiate and/or modify treatments.

  15. Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris

    SciTech Connect

    Selwyn, A.P.; Forse, G.; Fox, K.; Jonathan, A.; Steiner, R.

    1981-07-01

    Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a short-lived radionuclide, krypton-81m. Eleven patients had negative exercise tests and uniform increases in myocardial activity of krypton-81m of 98 +/- 18.0% during pacing. Ten patients performed 30,000-43,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and increases in myocardial activity of krypton-81m to remote and jeopardized myocardium at the onset of pacing. However, further pacing produced a decrease in activity in the affected segment of 68.0 +/- 9.0% accompanied by ST-segment depression and angina. Twelve patients achieved 26,000-32,000 J in positive exercise tests and had significant coronary artery disease. Atrial pacing produced increased activity of krypton-81m to remote myocardium. The jeopardized segment at first showed no change and then a decrease in regional activity of krypton-81m (89.0 +/- 17%) accompanied by ST-segment depression and chest pain. Seventeen patients achieved only 7000-22,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and developed decreases in regional activity of krypton-81m to the affected segment of myocardium starting at the onset of atrial pacing and decreasing by 88 +/- 0 7.0% below control. We conclude that different patterns of disturbed myocardial distribution of krypton-81m are present during stress-induced ischemia in patients with coronary artery disease. There was a close temporal relationship between these disturbances and ST-segment depression.

  16. In-vivo regional myocardial perfusion measurements in a porcine model by ECG-gated multislice computed tomography

    NASA Astrophysics Data System (ADS)

    Stantz, Keith M.; Liang, Yun; Meyer, Cristopher A.; Teague, Shawn; Stecker, Michael; Hutchins, Gary; McLennan, Gordon; Persohn, Scott

    2003-05-01

    Purpose: To evaluate whether functional multi-slice computed tomography (MSCT) can identify regional areas of normally perfused and ischemic myocardium in a porcine model. Material and Methods: Three out bred pigs, two of which had ameroids surgically implanted to constrict flow within the LAD and LCx coronary arteries, were injected with 25 mL of iopromide (Isovue) at a rate of 5 mL/second via the femoral or jugular vein. Sixty axial scans along the short axis of the heart was acquired on a 16-slice CT scanner (Philips MX8000-IDT) triggered at end-diastole of the cardiac cycle and acquiring an image within 270 msec. A second series of scans were taken after an intravenous injection of a vasodilator, 150 μg/kg/min of adenosine. ROIs were drawn around the myocardial tissue and the resulting time-density curves were used to extract perfusion values. Results: Determination of the myocardial perfusion and fractional blood volume implementing three different perfusion models. A 5-point averaging or 'smoothing' algorithm was employed to effectively filter the data due to its noisy nature. The (preliminary) average perfusion and fractional blood volume values over selected axial slices for the pig without an artificially induced stenosis were measured to be 84 +/- 22 mL/min/100g-tissue and 0.17 +/- 0.04 mL/g-tissue, the former is consistent with PET scan and EBCT results. The pig with a stenosis in the left LAD coronary artery showed a reduced global perfusion value -- 45 mL/min/100g-tissue. Correlations in regional perfusion values relative to the stenosis were weak. During the infusion of adenosine, averaged perfusion values for the three subjects increased by 46 (+/-45) percent, comparable to increases measured with PET. Conclusion: Quantifying global perfusion values using MDCT appear encouraging. Future work will focus resolving the systematic effects from noise due to signal fluctuation from the porcine tachyardia (80-93 BPM) and provide a more robust measurement

  17. Calpain Inhibition Improves Collateral Dependent Perfusion in a Hypercholesterolemic Swine Model of Chronic Myocardial Ischemia

    PubMed Central

    Sabe, Ashraf A.; Potz, Brittany A.; Elmadhun, Nassrene Y.; Liu, Yuhong; Feng, Jun; Abid, M. Ruhul; Abbott, Jinnette D; Senger, Donald R; Sellke, Frank W.

    2015-01-01

    Background Calpain over-expression is implicated in aberrant angiogenesis. We hypothesized that calpain inhibition (CI, MDL28170) would improve collateral perfusion in a swine model with hypercholesterolemia and chronic myocardial ischemia. Methods and Results Yorkshire swine fed a high cholesterol diet for 4 weeks underwent surgical placement of an ameroid constrictor to their left circumflex coronary artery. Three weeks later, animals received either: no drug, high cholesterol control group (HCC; n= 8); low dose CI (0.12 mg/kg; LCI, n= 9); or high dose CI (0.25 mg/kg; HCI, n= 8). The heart was harvested after 5 weeks. There was a trend toward increased right to left collateral vessels on angiography with HCI. Myocardial perfusion in ischemic myocardium significantly improved with HCI at rest and with demand pacing (p = 0.016 and 0.011). Endothelium-dependent microvessel relaxation was significantly improved with LCI (p = 0.001). There was a significant increase in capillary density, with LCI and HCI (p= 0.01 and 0.01), and arteriolar density with LCI (p= 0.001). CI significantly increased several proangiogenic proteins including VEGF (p= 0.02), VEGFR1 (p= 0.003), VEGFR2 (p= 0.003) and talin, a microvascular structural protein (p= 0.0002). There was a slight increase in proteins implicated in endothelial-dependent (NO Mediated) relaxation including ERK, p-ERK and iNOS with CI. Conclusions In the setting of hypercholesterolemia, CI improved perfusion, with a trend toward increased collateralization on angiography and increased capillary and arteriolar densities in ischemic myocardium. CI also improved endothelium-dependent microvessel relaxation and increased expression of proteins implicated in angiogenesis and vasodilatation. PMID:26478238

  18. System and method for assaying a radionuclide

    DOEpatents

    Cadieux, James R; King, III, George S; Fugate, Glenn A

    2014-12-23

    A system for assaying a radionuclide includes a liquid scintillation detector, an analyzer connected to the liquid scintillation detector, and a delay circuit connected to the analyzer. A gamma detector and a multi-channel analyzer are connected to the delay circuit and the gamma detector. The multi-channel analyzer produces a signal reflective of the radionuclide in the sample. A method for assaying a radionuclide includes selecting a sample, detecting alpha or beta emissions from the sample with a liquid scintillation detector, producing a first signal reflective of the alpha or beta emissions, and delaying the first signal a predetermined time. The method further includes detecting gamma emissions from the sample, producing a second signal reflective of the gamma emissions, and combining the delayed first signal with the second signal to produce a third signal reflective of the radionuclide.

  19. Dosimetry and Case Studies for Selected Radionuclides

    SciTech Connect

    Leggett, Richard Wayne

    2009-01-01

    This is a comprehensive review and analysis of biokinetic and dosimetric information for those radionuclides most likely to be involved in accidental exposures to workers or members of the public or used in radiological terrorism.

  20. Radionuclide carriers for targeting of cancer

    PubMed Central

    Sofou, Stavroula

    2008-01-01

    This review describes strategies for the delivery of therapeutic radionuclides to tumor sites. Therapeutic approaches are summarized in terms of tumor location in the body, and tumor morphology. These determine the radionuclides of choice for suggested targeting ligands, and the type of delivery carriers. This review is not exhaustive in examples of radionuclide carriers for targeted cancer therapy. Our purpose is two-fold: to give an integrated picture of the general strategies and molecular constructs currently explored for the delivery of therapeutic radionuclides, and to identify challenges that need to be addressed. Internal radiotherapies for targeting of cancer are at a very exciting and creative stage. It is expected that the current emphasis on multidisciplinary approaches for exploring such therapeutic directions should enable internal radiotherapy to reach its full potential. PMID:18686778

  1. An in vivo autotransplant model of renal preservation: cold storage versus machine perfusion in the prevention of ischemia/reperfusion injury.

    PubMed

    La Manna, Gaetano; Conte, Diletta; Cappuccilli, Maria Laura; Nardo, Bruno; D'Addio, Francesca; Puviani, Lorenza; Comai, Giorgia; Bianchi, Francesca; Bertelli, Riccardo; Lanci, Nicole; Donati, Gabriele; Scolari, Maria Piera; Faenza, Alessandro; Stefoni, Sergio

    2009-07-01

    There is increasing proof that organ preservation by machine perfusion is able to limit ischemia/reperfusion injury in kidney transplantation. This study was designed to compare the efficiency in hypothermic organ preservation by machine perfusion or cold storage in an animal model of kidney autotransplantation. Twelve pigs underwent left nephrectomy after warm ischemic time; the organs were preserved in machine perfusion (n = 6) or cold storage (n = 6) and then autotransplanted with immediate contralateral nephrectomy. The following parameters were compared between the two groups of animals: hematological and urine indexes of renal function, blood/gas analysis values, histological features, tissue adenosine-5'-triphosphate (ATP) content, perforin gene expression in kidney biopsies, and organ weight changes were compared before and after preservation. The amount of cellular ATP was significantly higher in organs preserved by machine perfusion; moreover, the study of apoptosis induction revealed an enhanced perforin expression in the kidneys, which underwent simple hypothermic preservation compared to the machine-preserved ones. Organ weight was significantly decreased after cold storage, but it remained quite stable for machine-perfused kidneys. The present model seems to suggest that organ preservation by hypothermic machine perfusion is able to better control cellular impairment in comparison with cold storage.

  2. Intravenous Administration of Endothelial Colony-Forming Cells Overexpressing Integrin β1 Augments Angiogenesis in Ischemic Legs.

    PubMed

    Goto, Kazuko; Takemura, Genzou; Takahashi, Tomoyuki; Okada, Hideshi; Kanamori, Hiromitsu; Kawamura, Itta; Watanabe, Takatomo; Morishita, Kentaro; Tsujimoto, Akiko; Miyazaki, Nagisa; Ushikoshi, Hiroaki; Kawasaki, Masanori; Mikami, Atsushi; Kosai, Ken-ichiro; Minatoguchi, Shinya

    2016-02-01

    When injected directly into ischemic tissue in patients with peripheral artery disease, the reparative capacity of endothelial progenitor cells (EPCs) appears to be limited by their poor survival. We, therefore, attempted to improve the survival of transplanted EPCs through intravenous injection and gene modification. We anticipated that overexpression of integrin β1 will enable injected EPCs to home to ischemic tissue, which abundantly express extracellular matrix proteins, the ligands for integrins. In addition, integrin β1 has an independent angiogenesis-stimulating function. Human endothelial colony-forming cells (ECFCs; late-outgrowth EPCs) were transduced using a lentiviral vector encoding integrin β1 (ITGB1) or enhanced green fluorescent protein (GFP). We then locally or systemically injected phosphate-buffered saline or the genetically modified ECFCs (GFP-ECFCs or ITGB1-ECFCs; 1 × 10(5) cells each) into NOD/Shi-scid, IL-2Rγnull mice whose right femoral arteries had been occluded 24 hours earlier. Upregulation of extracellular matrix proteins, including fibronectin, was apparent in the ischemic legs. Four weeks later, blood perfusion of the ischemic limb was significantly augmented only in the ITGB1-ECFC group. Scanning electron microscopy of vascular casts revealed increases in the perfused blood vessels in the ischemic legs of mice in the ITGB1-ECFC group and significant increases in the density of both capillaries and arterioles. Transplanted ECFC-derived vessels accounted for 28% ± 4.2% of the vessels in the ITGB1-ECFC group, with no cell fusion. Intravenous administration of ECFCs engineered to home to ischemic tissue appears to efficiently mediate therapeutic angiogenesis in a mouse model of peripheral artery disease. Significance: The intravenous administration of endothelial colony-forming cells (ECFCs) genetically modified to overexpress integrin β1 effectively stimulated angiogenesis in ischemic mouse hindlimbs. Transplanted ECFCs were

  3. Intravenous Administration of Endothelial Colony-Forming Cells Overexpressing Integrin β1 Augments Angiogenesis in Ischemic Legs

    PubMed Central

    Goto, Kazuko; Takahashi, Tomoyuki; Okada, Hideshi; Kanamori, Hiromitsu; Kawamura, Itta; Watanabe, Takatomo; Morishita, Kentaro; Tsujimoto, Akiko; Miyazaki, Nagisa; Ushikoshi, Hiroaki; Kawasaki, Masanori; Mikami, Atsushi; Kosai, Ken-ichiro; Minatoguchi, Shinya

    2016-01-01

    When injected directly into ischemic tissue in patients with peripheral artery disease, the reparative capacity of endothelial progenitor cells (EPCs) appears to be limited by their poor survival. We, therefore, attempted to improve the survival of transplanted EPCs through intravenous injection and gene modification. We anticipated that overexpression of integrin β1 will enable injected EPCs to home to ischemic tissue, which abundantly express extracellular matrix proteins, the ligands for integrins. In addition, integrin β1 has an independent angiogenesis-stimulating function. Human endothelial colony-forming cells (ECFCs; late-outgrowth EPCs) were transduced using a lentiviral vector encoding integrin β1 (ITGB1) or enhanced green fluorescent protein (GFP). We then locally or systemically injected phosphate-buffered saline or the genetically modified ECFCs (GFP-ECFCs or ITGB1-ECFCs; 1 × 105 cells each) into NOD/Shi-scid, IL-2Rγnull mice whose right femoral arteries had been occluded 24 hours earlier. Upregulation of extracellular matrix proteins, including fibronectin, was apparent in the ischemic legs. Four weeks later, blood perfusion of the ischemic limb was significantly augmented only in the ITGB1-ECFC group. Scanning electron microscopy of vascular casts revealed increases in the perfused blood vessels in the ischemic legs of mice in the ITGB1-ECFC group and significant increases in the density of both capillaries and arterioles. Transplanted ECFC-derived vessels accounted for 28% ± 4.2% of the vessels in the ITGB1-ECFC group, with no cell fusion. Intravenous administration of ECFCs engineered to home to ischemic tissue appears to efficiently mediate therapeutic angiogenesis in a mouse model of peripheral artery disease. Significance The intravenous administration of endothelial colony-forming cells (ECFCs) genetically modified to overexpress integrin β1 effectively stimulated angiogenesis in ischemic mouse hindlimbs. Transplanted ECFCs were observed

  4. Livermore Accelerator Source for Radionuclide Science (LASRS)

    SciTech Connect

    Anderson, Scott; Bleuel, Darren; Johnson, Micah; Rusnak, Brian; Soltz, Ron; Tonchev, Anton

    2016-05-05

    The Livermore Accelerator Source for Radionuclide Science (LASRS) will generate intense photon and neutron beams to address important gaps in the study of radionuclide science that directly impact Stockpile Stewardship, Nuclear Forensics, and Nuclear Material Detection. The co-location of MeV-scale neutral and photon sources with radiochemical analytics provides a unique facility to meet current and future challenges in nuclear security and nuclear science.

  5. Alchemy with short-lived radionuclides

    SciTech Connect

    Rubio, F.F.; Finn, R.D.; Gilson, A.J.

    1981-04-01

    A variety of short-lived radionuclides are produced and subsequently incorporated into radiopharmaceutical compounds in the radionuclide production program currently being conducted at the Cyclotron Facility of Mount Sinai Medical Center. The recovery of high specific activity oxygen-15 labelled water prepared by means of an inexpensive system operating in conjunction with an on-line radiogas target routinely utilized for oxygen-15 labelled carbon dioxide studies is currently receiving particular attention.

  6. The Mouse Isolated Perfused Kidney Technique.

    PubMed

    Czogalla, Jan; Schweda, Frank; Loffing, Johannes

    2016-11-17

    The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a prerequisite for studying the physiology of the isolated organ and for many innovative applications that may be possible in the future, including perfusion decellularization for kidney bioengineering or the administration of anti-rejection or genome-editing drugs in high doses to prime the kidney for transplantation. During the time of the perfusion, the kidney can be manipulated, renal function can be assessed, and various pharmaceuticals administered. After the procedure, the kidney can be transplanted or processed for molecular biology, biochemical analysis, or microscopy. This paper describes the perfusate and the surgical technique needed for the ex vivo perfusion of mouse kidneys. Details of the perfusion apparatus are given and data are presented showing the viability of the kidney's preparation: renal blood flow, vascular resistance, and urine data as functional, transmission electron micrographs of different nephron segments as morphological readouts, and western blots of transport proteins of different nephron segments as molecular readout.

  7. Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

  8. Centrifugal pump support for distal aortic perfusion during repair of traumatic thoracic aortic injury.

    PubMed

    Walls, Joseph T; Curtis, Jack J; McKenney-Knox, Charlotte A; Schmaltz, Richard A

    2002-11-01

    Paraplegia from ischemic injury of the spinal cord and renal failure from inadequate perfusion of the kidneys may occur from aortic cross-clamping during repair of traumatic thoracic aortic injuries. After Institutional Review Board approval, we retrospectively reviewed the charts of 26 patients surgically treated for traumatic transection of the descending thoracic aorta during a 14 year period (1987-2001), using centrifugal pump (Sarns) support for distal aortic perfusion. The study group comprised 19 males and 7 females, whose ages ranged from 15 to 69 years. For all but 1 patient, who fell from a flagpole, the injuries were incurred in motor vehicle accidents. Aortic cross-clamp time lasted between 5 to 78 min (median = 40 min). Mean arterial pressure ranged from 50 to 80 mm Hg (median = 70 mm Hg). All patients survived operation without developing paraplegia or renal failure. Distal centrifugal pump perfusion during repair of traumatic injury of the descending thoracic aorta is a valuable adjunct during surgical treatment and aids in preservation of spinal cord and renal function.

  9. Distribution of lung blood on modified bilateral Glenn shunt evaluated by Tc-99m-MAA lung perfusion scintigraphy: A retrospective study.

    PubMed

    Si, Biao; Luan, Zhao-Sheng; Wang, Tong-Jian; Ning, Yan-Song; Li, Na; Zhu, Meng; Liu, Zhong-Min; Ding, Guang-Hong; Qiao, Bin

    2016-09-01

    The aim of the present study was to determine the distribution of lung blood in a modified bilateral Glenn procedure designed in our institute with lung perfusion scintigraphy. Sixteen consecutive patients who underwent modified bilateral Glenn operation from 2011 to 2014 were enrolled in the study. The control group consisted of 7 patients who underwent bidirectional Glenn shunt. Radionuclide lung perfusion scintigraphy was performed using Tc-99m-macro aggregated albumin (MAA) in all patients. For the patients in modified bilateral Glenn group, the time at which the radioactivity accumulation peaked did not differ significantly between the right and left lung field (t = 0.608, P = 0.554). The incidence of perfusion abnormality in each lung lobe also did not differ significantly (P = 0.426 by Fisher exact test). The radioactive counts were higher in the right lung than in the left lung, but the difference was not statistically significant (t = 1.502, P = 0.157). Radioactive perfusion in the lower lung field was significantly greater than that in the upper field (t = 4.368, P < 0.001). Compared with that in the bidirectional Glenn group, the ratio of radioactivity in the right lung to that in left lung was significantly lower in the modified bilateral Glenn group (t = 3.686, P = 0.002). Lung perfusion scintigraphy confirmed the benefit of the modified bilateral Glenn shunt with regard to more balanced blood perfusion in both lungs.

  10. ISCHEMIC CONDITIONING PROTECTS THE MICROCIRCULATION, PRESERVES ORGAN FUNCTION, AND PROLONGS SURVIVAL IN SEPSIS.

    PubMed

    Orbegozo Cortés, Diego; Su, Fuhong; Santacruz, Carlos; Hosokawa, Koji; Donadello, Katia; Creteur, Jacques; De Backer, Daniel; Vincent, Jean-Louis

    2016-04-01

    Ischemic conditioning induces a series of cellular modifications that may prevent injury from further hypoxic episodes, but there are few data in sepsis. In this randomized controlled study, we evaluated the effects of ischemic conditioning on the microcirculation, organ function, and survival time in an ovine model of septic shock.Sepsis was induced in 14 anesthetized, mechanically ventilated adult sheep by injecting autologous feces into the abdominal cavity. Animals were then randomized to ischemic pre- and post-conditioning or no conditioning (both n = 7). Remote ischemic conditioning was performed by inflating the balloon of a catheter in the aortic bifurcation for 2 min, followed by a 4-min deflation period. The procedure was performed four times before sepsis induction and 4-hourly afterward. Animals were followed until death or for a maximum of 30 h. Hemodynamic, oxygenation, and microcirculatory variables were monitored. The conditioned group had higher mixed venous oxygen saturation from 8 h after randomization, higher cardiac index, and oxygen delivery from 16 h, and higher mean arterial pressure and lower lactate levels from 20 h. They also had greater renal blood flow, urine output, and creatinine clearance. Microcirculatory variables were better preserved in the conditioned than in the control group from 6 h after randomization: the median proportion of perfused vessels was 91 (89-93)% versus 89 (86-90)% (P = 0.024) and there was less heterogeneity. Oliguria, hypotension, and death occurred later in the conditioned than in the control group. In this sepsis model, remote ischemic pre- and post-conditioning therefore decreased organ dysfunction, preserved the microcirculation, and prolonged survival.

  11. Uptake of perfusion imaging agents by transplanted hearts: an experimental study in rats

    SciTech Connect

    Bergsland, J.; Carr, E.A. Jr.; Carroll, M.; Feldman, M.J.; Kung, H.; Wright, J.R.

    1989-02-01

    There is a need for a reliable noninvasive marker of rejection in transplanted hearts. Endomyocardial biopsy is now the universally accepted diagnostic method of choice, but the invasiveness of the procedure and the limited size of the sample obtained makes this method far from ideal. As coronary blood flow may be expected to decrease during acute rejection, there has been interest in thallium-201 chloride (T1), a perfusion marker, as an imaging agent for diagnosing cardiac rejection. Hexakis(t-butylisonitrile)-technetium (Tc-TBI) is a representative of a new class of radiopharmaceuticals proposed as perfusion markers. We have compared the uptake of these imaging agents in a rat model of cardiac transplantation. Uptake of Tc-TBI as well as of T1 was significantly lower in rejecting than in nonrejecting hearts. This change was found in both left (LV) and right (RV) ventricles. Allografts in animals treated with cyclosporine (CyA) showed less severe rejection and higher uptakes of both imaging agents as compared to unmodified rejection. Our results suggest that perfusion imaging with these radionuclides is a potentially useful approach to the problem of detecting allograft rejection.

  12. Radionuclide Air Emissions Report for 2012

    SciTech Connect

    Wahl, Linnea

    2013-05-01

    Berkeley Lab operates facilities where radionuclides are produced, handled, store d, and potentially emitted . These facilities are subject to the EPA radioactive air emission regulations in 40 CFR 61, Subpart H (EPA 1989a). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2012, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]) . These minor sources include d about 140 stack sources and no diffuse sources . T here were no unplanned airborne radionuclide emissions from Berkeley Lab operations . Emissions from minor sources were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building- specific and common parameters, Laboratory personnel applied the EPA -approved computer code s, CAP88-PC and COMPLY , to calculate doses to the maximally exposed individual (MEI) at any offsite point where there is a residence, school, business, or office. Because radionuclides are used at three noncontiguous locations (the main site, Berkeley West Bio center, and Joint BioEnergy Institute), three different MEIs were identified.

  13. Radionuclide scintigraphy of bacterial nephritis

    SciTech Connect

    Conway, J.J.; Weiss, S.C.; Shkolnik, A.; Yogev, R.; Firlit, C.; Traisman, E.S.

    1984-01-01

    Pyelonephritis is a leading cause of renal failure and is expected to cost as much as three billion dollars in 1984. The diagnosis of urinary tract infection is usually not difficult. However, localization of the infection within the renal parenchyma as opposed to the collecting system is much more difficult. Flank pain, fever, bacteiuria and evidence of parenchymal involvement by intravenous urography may be absent or unrecognized particularly in the infant. Ultrasound and Nuclear Medicine are advocated as better methods to define parenchymal involvement. Such definition is important in the consideration of treatment since parenchymal involvement of the kidney carries a much more ominous potential outcome than infection restricted to within the collecting system. 38 children with a clinical diagnosis of urinary tract infection were studied. 26 of the patients demonstrated abnormal renal parenchymal findings with Gallium-67 Citrate or Tc-99m Glucoheptonate scintigraphy. Intravenous urography was notably ineffective with only 5 of the 20 interpreted as abnormal due to parenchymal disease or decreased function. 11 were entirely normal while only 5 demonstrated scars or hydronephrosis. Only 10 of 17 patients demonstrated intranvesicoureteral reflux on x-ray or nuclear cystography. Ultrasound depicted 6 of 20 patients as having parenchymal abnormalities. Seven were normal. Nonspecific findings such as dilitation of the renal pelvis or renal enlargement was noted in 11 of the 20 patients. Radionuclide Scintigraphy is the most efficacious modality to detect since acute bacterial nephritis.

  14. Radionuclides in an underground environment

    SciTech Connect

    Thompson, J.L.

    1996-08-01

    In the 100 years since Becquerel recognized radioactivity, mankind has been very successful in producing large amounts of radioactive materials. We have been less successful in reaching a consensus on how to dispose of the billions of curies of fission products and transuranics resulting from nuclear weapons testing, electrical power generation, medical research, and a variety of other human endeavors. Many countries, including the United States, favor underground burial as a means of disposing of radioactive wastes. There are, however, serious questions about how such buried wastes may behave in the underground environment and particularly how they might eventually contaminate water, air and soil resources on which we are dependent. This paper describes research done in the United States in the state of Nevada on the behavior of radioactive materials placed underground. During the last thirty years, a series of ``experiments`` conducted for other purposes (testing of nuclear weapons) have resulted in a wide variety of fission products and actinides being injected in rock strata both above and below the water table. Variables which seem to control the movement of these radionuclides include the physical form (occlusion versus surface deposition), the chemical oxidation state, sorption by mineral phases of the host rock, and the hydrologic properties of the medium. The information gained from these studies should be relevant to planning for remediation of nuclear facilities elsewhere in the world and for long-term storage of nuclear wastes.

  15. Solubility limits on radionuclide dissolution

    SciTech Connect

    Kerrisk, J.F.

    1984-12-31

    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.

  16. A New Ischemic Model Using a Radiofrequency Wire Electrode in a Rabbit Hindlimb

    SciTech Connect

    Baik, Hye Won Kwak, Byung Kook; Shim, Hyung Jin; Kim, Yang Soo; Lee, Jong Beom; Kim, Kun Sang

    2008-07-15

    The purpose of this study was to establish an ischemic rabbit hindlimb model using a radiofrequency (RF) wire electrode. We inserted a polytetrafluoroethylene-coated wire with a 2-cm exposed tip into the left superficial femoral artery of seven New Zealand white rabbits and performed RF ablation (RFA) while pulling the wire back. We assessed the clinical findings, angiography, computed tomography perfusion, and permeability surface until 6 weeks after RFA. The angiography demonstrated complete obstruction from the proximal external iliac artery to the distal superficial femoral artery and showed a gradual increment in the angiogenic score, which represents the degree of angiogenesis (r = 0.86, p < 0.0001). The left-to-right ratios of the computed tomography perfusion and permeability surface were significantly reduced after 4 days (p < 0.05), and then they gradually increased with time. We conclude that endovascular RFA using an RF wire electrode is a reproducible and measurable way to create an ischemic rabbit hindlimb model.

  17. ISLES 2015 - A public evaluation benchmark for ischemic stroke lesion segmentation from multispectral MRI.

    PubMed

    Maier, Oskar; Menze, Bjoern H; von der Gablentz, Janina; Häni, Levin; Heinrich, Mattias P; Liebrand, Matthias; Winzeck, Stefan; Basit, Abdul; Bentley, Paul; Chen, Liang; Christiaens, Daan; Dutil, Francis; Egger, Karl; Feng, Chaolu; Glocker, Ben; Götz, Michael; Haeck, Tom; Halme, Hanna-Leena; Havaei, Mohammad; Iftekharuddin, Khan M; Jodoin, Pierre-Marc; Kamnitsas, Konstantinos; Kellner, Elias; Korvenoja, Antti; Larochelle, Hugo; Ledig, Christian; Lee, Jia-Hong; Maes, Frederik; Mahmood, Qaiser; Maier-Hein, Klaus H; McKinley, Richard; Muschelli, John; Pal, Chris; Pei, Linmin; Rangarajan, Janaki Raman; Reza, Syed M S; Robben, David; Rueckert, Daniel; Salli, Eero; Suetens, Paul; Wang, Ching-Wei; Wilms, Matthias; Kirschke, Jan S; Krämer, Ulrike M; Münte, Thomas F; Schramm, Peter; Wiest, Roland; Handels, Heinz; Reyes, Mauricio

    2017-01-01

    Ischemic stroke is the most common cerebrovascular disease, and its diagnosis, treatment, and study relies on non-invasive imaging. Algorithms for stroke lesion segmentation from magnetic resonance imaging (MRI) volumes are intensely researched, but the reported results are largely incomparable due to different datasets and evaluation schemes. We approached this urgent problem of comparability with the Ischemic Stroke Lesion Segmentation (ISLES) challenge organized in conjunction with the MICCAI 2015 conference. In this paper we propose a common evaluation framework, describe the publicly available datasets, and present the results of the two sub-challenges: Sub-Acute Stroke Lesion Segmentation (SISS) and Stroke Perfusion Estimation (SPES). A total of 16 research groups participated with a wide range of state-of-the-art automatic segmentation algorithms. A thorough analysis of the obtained data enables a critical evaluation of the current state-of-the-art, recommendations for further developments, and the identification of remaining challenges. The segmentation of acute perfusion lesions addressed in SPES was found to be feasible. However, algorithms applied to sub-acute lesion segmentation in SISS still lack accuracy. Overall, no algorithmic characteristic of any method was found to perform superior to the others. Instead, the characteristics of stroke lesion appearances, their evolution, and the observed challenges should be studied in detail. The annotated ISLES image datasets continue to be publicly available through an online evaluation system to serve as an ongoing benchmarking resource (www.isles-challenge.org).

  18. Imaging experimental cerebral malaria in vivo: significant role of ischemic brain edema.

    PubMed

    Penet, Marie-France; Viola, Angèle; Confort-Gouny, Sylviane; Le Fur, Yann; Duhamel, Guillaume; Kober, Frank; Ibarrola, Danielle; Izquierdo, Marguerite; Coltel, Nicolas; Gharib, Bouchra; Grau, Georges E; Cozzone, Patrick J

    2005-08-10

    The first in vivo magnetic resonance study of experimental cerebral malaria is presented. Cerebral involvement is a lethal complication of malaria. To explore the brain of susceptible mice infected with Plasmodium berghei ANKA, multimodal magnetic resonance techniques were applied (imaging, diffusion, perfusion, angiography, spectroscopy). They reveal vascular damage including blood-brain barrier disruption and hemorrhages attributable to inflammatory processes. We provide the first in vivo demonstration for blood-brain barrier breakdown in cerebral malaria. Major edema formation as well as reduced brain perfusion was detected and is accompanied by an ischemic metabolic profile with reduction of high-energy phosphates and elevated brain lactate. In addition, angiography supplies compelling evidence for major hemodynamics dysfunction. Actually, edema further worsens ischemia by compressing cerebral arteries, which subsequently leads to a collapse of the blood flow that ultimately represents the cause of death. These findings demonstrate the coexistence of inflammatory and ischemic lesions and prove the preponderant role of edema in the fatal outcome of experimental cerebral malaria. They improve our understanding of the pathogenesis of cerebral malaria and may provide the necessary noninvasive surrogate markers for quantitative monitoring of treatment.

  19. Calcium-sensing receptor: a sensor and mediator of ischemic preconditioning in the heart.

    PubMed

    Sun, Junhui; Murphy, Elizabeth

    2010-11-01

    As a G protein-coupled receptor, the extracellular Ca(2+)-sensing receptor (CaSR) responds to changes not only in extracellular Ca(2+), but also to many other ligands. CaSR has been found to be expressed in the hearts and cardiovascular system. In this study, we confirmed that CaSR is expressed in mouse cardiomyocytes and showed that it is predominantly localized in caveolae. The goal of this study was to investigate whether CaSR plays a cardioprotective role in ischemic preconditioning (IPC). Hearts from C57BL/6J mice (male, 12-16 wk) were perfused in the Langendorff mode and subjected to the following treatments: 1) control perfusion; 2) perfusion with a specific CaSR antagonist, NPS2143; 3) IPC (four cycles of 5 min of global ischemia and 5 min of reperfusion); or 4) perfusion with NPS2143 before and during IPC. Following these treatments, hearts were subjected to 20 min of no-flow global ischemia and 120 min of reperfusion. Compared with control, IPC significantly improved postischemic left ventricular functional recovery and reduced infarct size. Although NPS2143 perfusion alone did not change the hemodynamic function and did not change the extent of postischemic injury, NPS2143 treatment abolished cardioprotection of IPC. Through immunoblot analysis, it was demonstrated that IPC significantly increased the levels of phosphorylated ERK1/2, AKT, and GSK-3β, which were also prevented by NPS2143 treatment. Taken together, the distribution of CaSR in caveolae along with NPS2143-blockade of IPC-induced cardioprotective signaling suggest that the activation of CaSR during IPC is cardioprotective by a process involving caveolae.

  20. Ventilation-perfusion imaging in pulmonary papillomatosis

    SciTech Connect

    Espinola, D.; Rupani, H.; Camargo, E.E.; Wagner, H.N. Jr.

    1981-11-01

    Three children with laryngeal papillomas involving the lungs had serial ventilation-perfusion scintigrams to assess results of therapy designed to reduce the bronchial involvement. Different imaging patterns were observed depending on size, number, and location of lesions. In early parenchymal involvement a ventilation-perfusion mismatch was seen. The initial and follow-up studies correlated well with clinical and radiographic findings. This noninvasive procedure is helpful in evaluating ventilatory and perfusion impairment in these patients as well as their response to treatment.

  1. Cochlear perfusion with a viscous fluid.

    PubMed

    Wang, Yi; Olson, Elizabeth S

    2016-07-01

    The flow of viscous fluid in the cochlea induces shear forces, which could provide benefit in clinical practice, for example to guide cochlear implant insertion or produce static pressure to the cochlear partition or wall. From a research standpoint, studying the effects of a viscous fluid in the cochlea provides data for better understanding cochlear fluid mechanics. However, cochlear perfusion with a viscous fluid may damage the cochlea. In this work we studied the physiological and anatomical effects of perfusing the cochlea with a viscous fluid. Gerbil cochleae were perfused at a rate of 2.4 μL/min with artificial perilymph (AP) and sodium hyaluronate (Healon, HA) in four different concentrations (0.0625%, 0.125%, 0.25%, 0.5%). The different HA concentrations were applied either sequentially in the same cochlea or individually in different cochleae. The perfusion fluid entered from the round window and was withdrawn from basal scala vestibuli, in order to perfuse the entire perilymphatic space. Compound action potentials (CAP) were measured after each perfusion. After perfusion with increasing concentrations of HA in the order of increasing viscosity, the CAP thresholds generally increased. The threshold elevation after AP and 0.0625% HA perfusion was small or almost zero, and the 0.125% HA was a borderline case, while the higher concentrations significantly elevated CAP thresholds. Histology of the cochleae perfused with the 0.0625% HA showed an intact Reissner's membrane (RM), while in cochleae perfused with 0.125% and 0.25% HA RM was torn. Thus, the CAP threshold elevation was likely due to the broken RM, likely caused by the shear stress produced by the flow of the viscous fluid. Our results and analysis indicate that the cochlea can sustain, without a significant CAP threshold shift, up to a 1.5 Pa shear stress. Beside these finding, in the 0.125% and 0.25% HA perfusion cases, a temporary CAP threshold shift was observed, perhaps due to the presence and

  2. Stress-first single photon emission computed myocardial perfusion imaging

    PubMed Central

    Aquino, C I; Scarano, M; Squame, F; Casaburi, G; Nori, S L; Pace, L

    2016-01-01

    Background Myocardial perfusion imaging (MPI) with single photon emission tomography (SPET) is widely used in coronary artery disease evaluation. Recently major dosimetric concerns have arisen. The aim of this study was to evaluate if a pre-test scoring system could predict the results of stress SPET MPI, thus avoiding two radionuclide injections. Methods All consecutive patients (n=309) undergoing SPET MPI during the first 6 months of 2014 constituted the study group. The scoring system is based on these characteristics: age >65 years (1 point), diabetes (2 points), typical chest pain (2 points), congestive heart failure (3 points), abnormal ECG (4 points), male gender (4 points), and documented previous CAD (5 points). The patients were divided on the basis of the prediction score into 3 classes of risk for an abnormal stress-first protocol. Results An abnormal stress SPET MPI was present in 7/31 patients (23%) with a low risk score, in 24/90 (27%) with an intermediate score risk, and in 124/188 (66%) with an high score risk. ROC curve analysis showed good prediction of abnormal stress MPI. Conclusions Our results suggest an appropriate use of a pre-test clinical prediction formula of abnormal stress MPI in a routine clinical setting. PMID:27896227

  3. NGF promotes hemodynamic recovery in a rabbit hindlimb ischemic model through trkA- and VEGFR2-dependent pathways.

    PubMed

    Karatzas, Andreas; Katsanos, Konstantinos; Lilis, Ioannis; Papadaki, Helen; Kitrou, Panagiotis; Lecht, Shimon; Marcinkiewicz, Cezary; Siablis, Dimitris; Lelkes, Peter I; Lazarovici, Philip; Tsopanoglou, Nikos E

    2013-09-01

    Nerve growth factor (NGF) has been reported to play an important role in physiological and pathological angiogenesis. Based on these observations, we hypothesized that NGF may induce the formation of functional blood vessels in a hindlimb ischemic rabbit model. Hindlimb ischemia was induced in 34 rabbits bilaterally by endovascular embolization of femoral arteries. On the 7th, 14th, and 20th postembolization days, NGF was injected intramuscularly, in 1 ischemic limb, and vehicle was injected in the contralateral control limb. On the 40th day, newly developed collateral vessels (diameter >500 μm) were quantified by transauricular intraarterial subtraction angiography. Perfusion analysis of an in vivo dynamic computed tomography study was performed to the limbs to investigate the hemodynamic recovery of the distal ischemic tissues. Functional estimation of limb perfusion showed a statistically significant increase of blood flow and blood volume for NGF. However, the increase of the collateral vessels was not detectable angiographically, providing evidence for the existence of a NGF-stimulated capillary angiogenic network but not increase of arteriogenesis. The combination of NGF with either tropomyosin-related kinase type A or vascular endothelial growth factor receptor 2 antagonists abolished the NGF-induced hemodynamic recovery. These findings provide new insights into understanding the involvement of NGF in vascular formation and its applications in therapeutic angiogenesis.

  4. Tissue-engineered pro-angiogenic fibroblast scaffold improves myocardial perfusion and function and limits ventricular remodeling after infarction

    PubMed Central

    Fitzpatrick, J. Raymond; Frederick, John R.; McCormick, Ryan C.; Harris, David A.; Kim, Ah-Young; Muenzer, Jeffrey R.; Gambogi, Alex J.; Liu, Jing Ping; Paulson, E. Carter; Woo, Y. Joseph

    2011-01-01

    Objective Microvascular malperfusion after myocardial infarction leads to infarct expansion, adverse remodeling, and functional impairment. Native reparative mechanisms exist but are inadequate to vascularize ischemic myocardium. We hypothesized that a 3-dimensional human fibroblast culture (3DFC) functions as a sustained source of angiogenic cytokines, thereby augmenting native angiogenesis and limiting adverse effects of myocardial ischemia. Methods Lewis rats underwent ligation of the left anterior descending coronary artery to induce heart failure; experimental animals received a 3DFC scaffold to the ischemic region. Border-zone tissue was analyzed for the presence of human fibroblast surface protein, vascular endothelial growth factor, and hepatocyte growth factor. Cardiac function was assessed with echocardiography and pressure–volume conductance. Hearts underwent immunohistochemical analysis of angiogenesis by co-localization of platelet endothelial cell adhesion molecule and alpha smooth muscle actin and by digital analysis of ventricular geometry. Microvascular angiography was performed with fluorescein-labeled lectin to assess perfusion. Results Immunoblotting confirmed the presence of human fibroblast surface protein in rats receiving 3DFC, indicating survival of transplanted cells. Increased expression of vascular endothelial growth factor and hepatocyte growth factor in experimental rats confirmed elution by the 3DFC. Microvasculature expressing platelet endothelial cell adhesion molecule/alpha smooth muscle actin was increased in infarct and border-zone regions of rats receiving 3DFC. Microvascular perfusion was also improved in infarct and border-zone regions in these rats. Rats receiving 3DFC had increased wall thickness, smaller infarct area, and smaller infarct fraction. Echocardiography and pressure–volume measurements showed that cardiac function was preserved in these rats. Conclusions Application of a bioengineered 3DFC augments native

  5. Change in skin perfusion pressure after the creation of upper limb arteriovenous fistula for maintenance hemodialysis access.

    PubMed

    Sueki, Shina; Sakurada, Tsutomu; Miyamoto, Masahito; Tsuruoka, Kayori; Matsui, Katsuomi; Sato, Yuichi; Shibagaki, Yugo; Kimura, Kenjiro

    2014-10-01

    Arteriovenous fistula (AVF) is the most important vascular access method for hemodialysis (HD). However, ischemic steal syndrome occasionally develops. This study evaluated the change in skin perfusion pressure (SPP) after the creation of upper limb AVF and analyzed the relationship between blood flow measurements and the change in SPP. The subjects included 21 patients who underwent radiocephalic AVF creation for the first time between November 2012 and September 2013. We measured SPP on the palm side of the third finger of both hands and assessed blood flow measurements using ultrasound examination before and after the creation of AVF. The subjects consisted of 15 men and 6 women (average age: 65.3 ± 12.7 years, including 12 diabetic patients). Observational period between before and after surgery was 4.9 ± 5.2 days. None of the patients had ischemic steal syndrome after the creation of AVF. Skin perfusion pressure tended to decrease after creation of AVF on the finger of AVF side (100.0 ± 20.9 vs. 87.9 ± 26.5 mmHg, P = 0.063). In contrast, SPP did not change in the limb without AVF (97.9 ± 20.7 vs. 101.0 ± 19.4 mmHg, P = 0.615). The rate of change in SPP was significantly decreased on the finger of AVF side compared with that of limb without AVF (0.055% vs. -0.112%, P = 0.014). There was no correlation between the change in SPP and blood flow measurements. Skin perfusion pressure is possible to detect ischemic steal syndrome after the creation of upper limb AVF.

  6. Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging.

    PubMed

    Howarth, N R; Beziat, C; Berthezène, Y

    1999-01-01

    Pulmonary perfusion defects can be demonstrated with contrast-enhanced dynamic MR perfusion imaging. We present the case of a patient with a pulmonary artery sarcoma who presented with a post-operative pulmonary embolus and was followed in the post-operative period with dynamic contrast-enhanced MR perfusion imaging. This technique allows rapid imaging of the first passage of contrast material through the lung after bolus injection in a peripheral vein. To our knowledge, this case report is the first to describe the use of this MR technique in showing the evolution of peripheral pulmonary perfusion defects associated with pulmonary emboli.

  7. Optical micro-angiography images structural and functional cerebral blood perfusion in mice with cranium left intact.

    PubMed

    Jia, Yali; Wang, Ruikang K

    2011-01-01

    Alteration in regional cerebral blood flow (CBF) is the direct result of changes in neuronal activity. It is crucial to monitor the spatio-temporal characteristics of cerebro-vascular blood perfusion in the studies of cerebral diseases. Optical micro-angiography (OMAG) is a recently developed imaging technique capable of resolving 3D distribution of dynamic blood perfusion at a capillary level resolution within microcirculatory beds in vivo. The authors report the applications of OMAG in mouse ischemic stroke model. The study demonstrates that OMAG is a useful method capable of providing in vivo serial assessment of 3D cerebro-vascular pathophysiology with high sensitivity, and therefore, has the potential for use in the study of brain disorders and repairs.

  8. Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage.

    PubMed

    Malinova, Vesna; Dolatowski, Karoline; Schramm, Peter; Moerer, Onnen; Rohde, Veit; Mielke, Dorothee

    2016-07-01

    OBJECT This prospective study investigated the role of whole-brain CT perfusion (CTP) studies in the identification of patients at risk for delayed ischemic neurological deficits (DIND) and of tissue at risk for delayed cerebral infarction (DCI). METHODS Forty-three patients with aneurysmal subarachnoid hemorrhage (aSAH) were included in this study. A CTP study was routinely performed in the early phase (Day 3). The CTP study was repeated in cases of transcranial Doppler sonography (TCD)-measured blood flow velocity (BFV) increase of > 50 cm/sec within 24 hours and/or on Day 7 in patients who were intubated/sedated. RESULTS Early CTP studies revealed perfusion deficits in 14 patients, of whom 10 patients (72%) developed DIND, and 6 of these 10 patients (60%) had DCI. Three of the 14 patients (21%) with early perfusion deficits developed DCI without having had DIND, and the remaining patient (7%) had neither DIND nor DCI. There was a statistically significant correlation between early perfusion deficits and occurrence of DIND and DCI (p < 0.0001). A repeated CTP was performed in 8 patients with a TCD-measured BFV increase > 50 cm/sec within 24 hours, revealing a perfusion deficit in 3 of them (38%). Two of the 3 patients (67%) developed DCI without preceding DIND and 1 patient (33%) had DIND without DCI. In 4 of the 7 patients (57%) who were sedated and/or comatose, additional CTP studies on Day 7 showed perfusion deficits. All 4 patients developed DCI. CONCLUSIONS Whole-brain CTP on Day 3 after aSAH allows early and reliable identification of patients at risk for DIND and tissue at risk for DCI. Additional CTP investigations, guided by TCD-measured BFV increase or persisting coma, do not contribute to information gain.

  9. Quantitative, dynamic and noninvasive determination of skeletal muscle perfusion in mouse leg by NMR arterial spin-labeled imaging.

    PubMed

    Bertoldi, Didier; Loureiro de Sousa, Paulo; Fromes, Yves; Wary, Claire; Carlier, Pierre G

    2008-11-01

    Because mouse may relatively easily be genetically tailored to develop equivalent of human muscular diseases or to present controlled alterations of mechanisms involved in vasoregulation, it has become the prevalent species to explore such questions. However, the very small size of the animals represents a serious limitation when evaluating the functional consequences of these genetic manipulations. In this context, the recourse to arterial spin labeling (ASL) nuclear magnetic resonance (NMR) methods in which arterial water spins act as an endogenous and freely diffusible tracer of perfusion is tempting but challenging. This article shows that despite the small size of the animal, mouse muscle perfusion may be measured, at rest and in conditions of reactive hyperemia, using saturation inversion recovery sequence, a pulsed ASL variant, combined with NMR imaging. Baseline perfusion values in the mouse leg were 17+/-11 ml.min(-1).100 g(-1) (n=11) and were comparable to microsphere data from the literature. Under ischemia, leg perfusion was 1.2+/-9.3 ml.min(-1).100 g(-1) (n=11). The difference observed between basal and ischemic measurements was statistically different (P=.0001). The temporal pattern of hyperemia in mouse muscle was coherent with previously published measurements in humans and in rats. The mean peak perfusion was 62+/-24 ml.min(-1).100 g(-1) (n=6) occurring 48+/-27 s after the end of occlusion. In conclusion, this study demonstrated the ability of ASL combined to NMR imaging to quantify skeletal muscle perfusion in mice legs, both at rest and dynamically.

  10. Improved exercise myocardial perfusion during lidoflazine therapy

    SciTech Connect

    Shapiro, W.; Narahara, K.A.; Park, J.

    1983-11-01

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

  11. Response of cyt a,a3 in the situ canine heart to transient ischemic episodes.

    PubMed

    Snow, T R; Kleinmann, L H; LaManna, J C; Wechsler, A S; Jöbsis, F F

    1981-01-01

    Experiments were performed to examine the response of cyt a,a3 to transient ischemic and hypoxic episodes in the empty, fibrillating canine heart in situ. Using a dual wavelength, differential spectrophotometer, reaction spectra show an absorption peak at approximately 605 nm consistent with that obtained from purified cyt a,a3. The characteristics of the averaged reaction spectrum in the interval 590 nm to 610 nm indicate that hemoglobin/myoglobin contribute no more than 23% to the signal measured at 605 nm. A regimen of one 30 sec global ischemia (GI) repeated once every 3 minutes over a 90 min period showed no appreciable signal deterioration. Therefore, five such interventions were subsequently used as the test perturbation. Studies of the effects of ischemic episodes of 30 and 60 min show that the response of cyt a,a3 to this test intervention was smaller (90 +/- 6% and 89 +/- 7%) than that observed prior to the ischemic episode. Changes in coronary perfusion pressure (+/- 10 Torr) produced an immediate oxidation/reduction of cyt a,a3. In the working heart, just prior to fibrillation, 6 sec to interrupted ventilation resulted in a continuous reduction of cyt a,a3. The data from these studies show: 1) The redox state of cyt a,a3 may be continuously monitored in the canine heart in situ. 2) Following ischemias of 30 and 60 min duration, respiratory chain function may be impaired; and 3) The well-perfused epicardium is extremely sensitive to small changes in oxygen delivery.

  12. Perfusion visualization and analysis for pulmonary embolism

    NASA Astrophysics Data System (ADS)

    Vaz, Michael S.; Kiraly, Atilla P.; Naidich, David P.; Novak, Carol L.

    2005-04-01

    Given the nature of pulmonary embolism (PE), timely and accurate diagnosis is critical. Contrast enhanced high-resolution CT images allow physicians to accurately identify segmental and sub-segmental emboli. However, it is also important to assess the effect of such emboli on the blood flow in the lungs. Expanding upon previous research, we propose a method for 3D visualization of lung perfusion. The proposed method allows users to examine perfusion throughout the entire lung volume at a single glance, with areas of diminished perfusion highlighted so that they are visible independent of the viewing location. This may be particularly valuable for better accuracy in assessing the extent of hemodynamic alterations resulting from pulmonary emboli. The method also facilitates user interaction and may help identify small peripheral sub-segmental emboli otherwise overlooked. 19 patients referred for possible PE were evaluated by CT following the administration of IV contrast media. An experienced thoracic radiologist assessed the 19 datasets with 17 diagnosed as being positive for PE with multiple emboli. Since anomalies in lung perfusion due to PE can alter the distribution of parenchymal densities, we analyzed features collected from histograms of the computed perfusion maps and demonstrate their potential usefulness as a preliminary test to suggest the presence of PE. These histogram features also offer the possibility of distinguishing distinct patterns associated with chronic PE and may even be useful for further characterization of changes in perfusion or overall density resulting from associated conditions such as pneumonia or diffuse lung disease.

  13. Deconvolution with simple extrapolation for improved cerebral blood flow measurement in dynamic susceptibility contrast magnetic resonance imaging during acute ischemic stroke.

    PubMed

    MacDonald, Matthew Ethan; Smith, Michael Richard; Frayne, Richard

    2011-06-01

    Magnetic resonance (MR) perfusion imaging is a clinical technique for measuring brain blood flow parameters during stroke and other ischemic events. Ischemia in brain tissue can be difficult to accurately measure or visualize when using MR-derived cerebral blood flow (CBF) maps. The deconvolution techniques used to estimate flow can introduce a mean transit time-dependent bias following application of noise stabilization techniques. The underestimation of the CBF values, greatest in normal tissues, causes a decrease in the image contrast observed in CBF maps between normally perfused and ischemic tissues; resulting in ischemic areas becoming less conspicuous. Through application of the proposed simple extrapolation technique, CBF biases are reduced when missing high-frequency signal components in the MR data removed during deconvolution noise stabilization are restored. The extrapolation approach was compared with other methods and showed a statistically significant increase in image contrast in CBF maps between normal and ischemic tissues for white matter (P<.05) and performed better than most other methods for gray matter. Receiver operator characteristic curve analysis demonstrated that extrapolated CBF maps better-detected penumbral regions. Extrapolated CBF maps provided more accurate CBF estimates in simulations, suggesting that the approach may provide a better prediction of outcome in the absence of treatment.

  14. Free-breathing myocardial perfusion MRI using SW-CG-HYPR and motion correction.

    PubMed

    Ge, Lan; Kino, Aya; Griswold, Mark; Carr, James C; Li, Debiao

    2010-10-01

    First-pass perfusion MRI is a promising technique to detect ischemic heart disease. Sliding window (SW) conjugate-gradient (CG) highly constrained back-projection reconstruction (HYPR) (SW-CG-HYPR) has been proposed to increase spatial coverage, spatial resolution, and SNR. However, this method is sensitive to respiratory motion and thus requires breath-hold. This work presents a non-model-based motion correction method combined with SW-CG-HYPR to perform free-breathing myocardial MR imaging. Simulation studies were first performed to show the effectiveness of the proposed motion correction method and its independence from the pattern of the respiratory motion. After that, in vivo studies were performed in six healthy volunteers. From all of the volunteer studies, the image quality score of free breathing perfusion images with motion correction (3.11 ± 0.34) is improved compared with that of images without motion correction (2.27 ± 0.32), and is comparable with that of successful breath-hold images (3.12 ± 0.38). This result was further validated by a quantitative sharpness analysis. The left ventricle and myocardium signal changes in motion corrected free-breathing perfusion images were closely correlated to those observed in breath-hold images. The correlation coefficient is 0.9764 for myocardial signals. Bland-Altman analysis confirmed the agreement between the free-breathing SW-CG-HYPR method with motion correction and the breath-hold SW-CG-HYPR. This technique may allow myocardial perfusion MRI during free breathing.

  15. Serial myocardial perfusion imaging: defining a significant change and targeting management decisions.

    PubMed

    Iskandrian, Ami E; Hage, Fadi G; Shaw, Leslee J; Mahmarian, John J; Berman, Daniel S

    2014-01-01

    Myocardial perfusion imaging (MPI) with gated single-photon emission tomography provides important information on the extent and severity of myocardial perfusion abnormalities, including myocardial ischemia. The availability of software for automated quantitative assessment of myocardial perfusion in an objective and more reproducible manner than visual assessment has allowed MPI to be particularly effective in serial evaluation. Serial testing using MPI is widely used in guiding patient care despite the lack of well-defined appropriateness use criteria. This should not be surprising because ischemic heart disease is a life-long malady subject to dynamic changes throughout its natural course and particularly following man-made interventions that may improve or worsen the disease process, such as medical therapy and coronary revascularization. Serial MPI has filled an important clinical gap by providing crucial information for managing patients with changes in clinical presentations or in anticipation of such changes in patients with stable symptoms. In the research arena, serial MPI has been widely applied in randomized controlled trials to study the impact of various medical and interventional therapies on myocardial perfusion, as well as the relative merits of new imaging procedures (hardware and/or software), radiotracers, and stressor agents. Serial testing, however, unlike initial or 1-time testing, has more stringent requirements and is subject to variability because of technical, procedural, interpretational, and biological factors. The intrinsic variability of MPI becomes important in interpreting serial tests in order to define a true change in a given patient and to guide clinical decision making. The purpose of this first comprehensive review on this subject is to illustrate where serial MPI may be useful clinically and in research studies, and to highlight strategies for addressing the various issues that are unique to serial testing in order to derive

  16. First steps in membrane oxygenation and prolonged extracorporeal perfusion in Duesseldorf using the Bramson membrane lung.

    PubMed

    Schulte, Hagen D

    2003-05-01

    After a shortened history of conventional closed and open heart surgery, including hypothermia by surface cooling and extracorporeal circulation, the first application of a new membrane oxygenator developed by ML Bramson with an integrated temperature exchange system and a heart-lung machine (HLM) was reported in 1972. The aim was to have an efficient oxygenating and gas exchange artificial lung that allowed prolonged perfusions in patients with cardiogenic shock or acute respiratory insufficiency. After in vitro closed recirculation studies comparing different bubble, vertical screen, and the new membrane oxygenators, the Bramson HLM was used in dog experiments before starting clinical cardiac surgery with routine interventions (closure of an atrial septal defect). The first clinically prolonged support for more than three hours after a double valve replacement in a NYHA class IV patient failed. A partial venoarterial prolonged perfusion for 42 hours and 43 minutes in a 10-year-old girl after surgical correction of a partial av canal defect and postoperative development of consistent lung edema caused by myocardial failure after an ischemic time of 43 minutes was the first successful long-term perfusion case in Europe. These first experiences with the Bramson membrane lung formed the basis, in our group, for further investigations of different perfusion routes and cannulations in animal experiments. Also, scanning electron microscopy studies could be performed with experimentally and clinically used membranes. The development of disposable membrane lung devices, for instance, Lande-Edwards, Kolobow Scimed, and General Electric Peirce membrane lungs, ameliorated and improved the use of these devices considerably. Also, BRAMSON had developed a disposable membrane lung device that had proved to be very effective in animal experiments by 1972, but, unfortunately, this device did not become commercially available.

  17. Effects of cerebral ischemic and reperfusion on T2*-weighted MRI responses to brief oxygen challenge.

    PubMed

    Shen, Qiang; Du, Fang; Huang, Shiliang; Duong, Timothy Q

    2014-01-01

    This study characterized the effects of cerebral ischemia and reperfusion on T2*-weighted magnetic resonance image (MRI) responses to brief oxygen challenge (OC) in transient (60 minutes) cerebral ischemia in rats. During occlusion, the ischemic core tissue showed no significant OC response, whereas the perfusion-diffusion mismatch tissue showed markedly higher percent changes relative to normal tissue. After reperfusion, much of the pixels with initial exaggerated OC responses showed normal OC responses, and the majority of these tissues were salvaged as defined by endpoint T2 MRI. The initial core pixels showed exaggerated OC responses after reperfusion, but the majority of the core pixels eventually became infarct, suggesting exaggerated OC responses do not necessarily reflect salvageable tissue. Twenty-four hours after stroke, basal T1 increased in the ischemic core. Oxygen challenge decreased T1 significantly in the core, indicative of the substantial increases in dissolved oxygen in the core as the result of hyperperfusion. We concluded that exaggerated T2*-weighted MRI responses to OC offer useful insight in ischemic tissue fates. However, exaggerated OC pixels are not all salvageable, and they exhibited complex dynamics depending on reperfusion status, hyperperfusion, and edema effects.

  18. Dynamic functional cerebral blood volume responses to normobaric hyperoxia in acute ischemic stroke

    PubMed Central

    Wu, Ona; Lu, Jie; Mandeville, Joseph B; Murata, Yoshihiro; Egi, Yasu; Dai, Guangping; Marota, John J; Diwan, Izzuddin; Dijkhuizen, Rick M; Kwong, Kenneth K; Lo, Eng H; Singhal, Aneesh B

    2012-01-01

    Studies suggest that neuroprotective effects of normobaric oxygen (NBO) therapy in acute stroke are partly mediated by hemodynamic alterations. We investigated cerebral hemodynamic effects of repeated NBO exposures. Serial magnetic resonance imaging (MRI) was performed in Wistar rats subjected to focal ischemic stroke. Normobaric oxygen-induced functional cerebral blood volume (fCBV) responses were analyzed. All rats had diffusion-weighted MRI (DWI) lesions within larger perfusion deficits, with DWI lesion expansion after 3 hours. Functional cerebral blood volume responses to NBO were spatially and temporally heterogeneous. Contralateral healthy tissue responded consistently with vasoconstriction that increased with time. No significant responses were evident in the acute DWI lesion. In hypoperfused regions surrounding the acute DWI lesion, tissue that remained viable until the end of the experiment showed relative preservation of mean fCBV at early time points, with some rats showing increased fCBV (vasodilation); however, these regions later exhibited significantly decreased fCBV (vasoconstriction). Tissue that became DWI abnormal by study-end initially showed marginal fCBV changes that later became moderate fCBV reductions. Our results suggest that a reverse-steal hemodynamic effect may occur in peripheral ischemic zones during NBO treatment of focal stroke. In addition, CBV responses to NBO challenge may have potential as an imaging marker to distinguish ischemic core from salvageable tissues. PMID:22739619

  19. Multimodal imaging of ischemic wounds

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    The wound healing process involves the reparative phases of inflammation, proliferation, and remodeling. Interrupting any of these phases may result in chronically unhealed wounds, amputation, or even patient death. Quantitative assessment of wound tissue ischemia, perfusion, and inflammation provides critical information for appropriate detection, staging, and treatment of chronic wounds. However, no method is available for noninvasive, simultaneous, and quantitative imaging of these tissue parameters. We integrated hyperspectral, laser speckle, and thermographic imaging modalities into a single setup for multimodal assessment of tissue oxygenation, perfusion, and inflammation characteristics. Advanced algorithms were developed for accurate reconstruction of wound oxygenation and appropriate co-registration between different imaging modalities. The multimodal wound imaging system was validated by an ongoing clinical trials approved by OSU IRB. In the clinical trial, a wound of 3mm in diameter was introduced on a healthy subject's lower extremity and the healing process was serially monitored by the multimodal imaging setup. Our experiments demonstrated the clinical usability of multimodal wound imaging.

  20. Radionuclide Retention in Concrete Waste Forms

    SciTech Connect

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  1. Radionuclide Retention in Concrete Wasteforms - FY13

    SciTech Connect

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  2. Radionuclide Mobility at the Nevada Test Site

    SciTech Connect

    Hu, Q; Smith, D; Rose, T; Glascoe, L; Steefel, C; Zavarin, M

    2003-11-13

    Underground nuclear tests conducted at the Nevada Test Site (NTS) are characterized by abundant fission product and actinide source terms. Included are {sup 99}Tc and other soluble radionuclides ({sup 3}H, {sup 14}C, {sup 36}Cl, {sup 85}Kr, and {sup 129}I), which are presumably mobile in groundwater and potentially toxic to down-gradient receptors. NTS provides the Office of Civilian Radioactive Waste Management (OCRWM) with an analog of the release of these radionuclides from a nuclear waste repository in the absence of engineered barriers. The investigation described in this report synthesizes a substantial body of data collected on the identity and distribution of soluble radionuclides at field scales over distances of hundreds of meters, for durations up to 40 years, and under hydrogeologic conditions very similar to the proposed geological repository at Yucca Mountain. This body of data is complemented by laboratory transport studies and a synthesis of recent modeling investigations from the NTS, with an emphasis on the ongoing Yucca Mountain Program (YMP) efforts. Overall, understanding the controls of radionuclide mobility associated with these nuclear tests will provide insight into the repository's future performance as well as bounds and calibrations for the numerical predictions of long-term radionuclide releases and migration.

  3. Idaho radionuclide exposure study: Literature review

    SciTech Connect

    Baker, E.G.; Freeman, H.D.; Hartley, J.N.

    1987-10-01

    Phosphate ores contain elevated levels of natural radioactivity, some of which is released to the environment during processing or use of solid byproducts. The effect of radionuclides from Idaho phosphate processing operations on the local communities has been the subject of much research and study. The literature is reviewed in this report. Two primary radionuclide pathways to the environment have been studied in detail: (1) airborne release of volatile radionuclides, primarily /sup 210/Po, from calciner stacks at the two elemental phosphorus plants; and (2) use of byproduct slag as an aggregate for construction in Soda Springs and Pocatello. Despite the research, there is still no clear understanding of the population dose from radionuclide emissions, effluents, and solid wastes from phosphate processing plants. Two other potential radionuclide pathways to the environment have been identified: radon exhalation from phosphogypsum and ore piles and contamination of surface and ground waters. Recommendations on further study needed to develop a data base for a complete risk assssment are given in the report.

  4. Fast analysis of radionuclide decay chain migration

    NASA Astrophysics Data System (ADS)

    Chen, J. S.; Liang, C. P.; Liu, C. W.; Li, L.

    2014-12-01

    A novel tool for rapidly predicting the long-term plume behavior of an arbitrary length radionuclide decay chain is presented in this study. This fast tool is achieved based on generalized analytical solutions in compact format derived for a set of two-dimensional advection-dispersion equations coupled with sequential first-order decay reactions in groundwater system. The performance of the developed tool is evaluated by a numerical model using a Laplace transform finite difference scheme. The results of performance evaluation indicate that the developed model is robust and accurate. The developed model is then used to fast understand the transport behavior of a four-member radionuclide decay chain. Results show that the plume extents and concentration levels of any target radionuclide are very sensitive to longitudinal, transverse dispersion, decay rate constant and retardation factor. The developed model are useful tools for rapidly assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

  5. Enhanced phosphodiesteratic breakdown and turnover of phosphoinositides during reperfusion of ischemic rat heart.

    PubMed

    Otani, H; Prasad, M R; Engelman, R M; Otani, H; Cordis, G A; Das, D K

    1988-11-01

    In this study, we examined phosphoinositide metabolism during ischemia and reperfusion using an isolated and perfused rat heart. When myocardial phosphoinositides were prelabeled with [3H]inositol, reperfusion after 30 minutes of normothermic global ischemia resulted in significant accumulations of radiolabeled inositol phosphate, inositol bisphosphate, and inositol trisphosphate. Isotopic incorporation of [3H]inositol into phosphatidylinositol, phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-bisphosphate was increased significantly in the heart reperfused with [3H]inositol after 30 minutes of ischemia compared with that perfused with [3H]inositol after 30 minutes of nonischemic perfusion. However, isotopic incorporation of [3H]glycerol into diacylglycerol, phosphatidic acid, and all of the three phosphoinositides was diminished in the reperfused hearts. Reperfusion of the ischemic heart prelabeled with [14C]arachidonic acid resulted in significant increases in [14C]diacylglycerol and [14C]phosphatidic acid. The enhanced accumulations of [3H]inositol phosphates during reperfusion were not affected by treatment with prazosin plus atropine or indomethacin, but were inhibited by hypoxic reperfusion, reperfusion with Ca2+-free buffer, or by mepacrine. These results suggest that myocardial reperfusion stimulates phosphodiesteratic breakdown and turnover of phosphoinositides, and increased Ca2+ influx caused by reperfusion may be involved in the mechanism of stimulation of phosphatidylinositol-specific phospholipase C activity in the rat heart.

  6. Erythropoietin: Powerful Protection of Ischemic and Post-Ischemic Brain

    PubMed Central

    Nguyen, Anh Q.; Cherry, Brandon H.; Scott, Gary F.; Ryou, Myoung-Gwi; Mallet, Robert T.

    2015-01-01

    Ischemic brain injury inflicted by stroke and cardiac arrest ranks among the leading causes of death and long-term disability in the United States. The brain consumes large amounts of metabolic substrates and oxygen to sustain its energy requirements. Consequently, the brain is exquisitely sensitive to interruptions in its blood supply, and suffers irreversible damage after 10–15 minutes of severe ischemia. Effective treatments to protect the brain from stroke and cardiac arrest have proven elusive, due to the complexities of the injury cascades ignited by ischemia and reperfusion. Although recombinant tissue plasminogen activator and therapeutic hypothermia have proven efficacious for stroke and cardiac arrest, respectively, these treatments are constrained by narrow therapeutic windows, potentially detrimental side effects and the limited availability of hypothermia equipment. Mounting evidence demonstrates the cytokine hormone erythropoietin (EPO) to be a powerful neuroprotective agent and a potential adjuvant to established therapies. Classically, EPO originating primarily in the kidneys promotes erythrocyte production by suppressing apoptosis of proerythroid progenitors in bone marrow. However, the brain is capable of producing EPO, and EPO’s membrane receptors and signaling components also are expressed in neurons and astrocytes. EPO activates signaling cascades that increase the brain’s resistance to ischemia-reperfusion stress by stabilizing mitochondrial membranes, limiting formation of reactive oxygen and nitrogen intermediates, and suppressing pro-inflammatory cytokine production and neutrophil infiltration. Collectively, these mechanisms preserve functional brain tissue and, thus, improve neurocognitive recovery from brain ischemia. This article reviews the mechanisms mediating EPO-induced brain protection, critiques the clinical utility of exogenous EPO to preserve brain threatened by ischemic stroke and cardiac arrest, and discusses the

  7. 2014 LANL Radionuclide Air Emissions Report

    SciTech Connect

    Fuehne, David Patrick

    2015-07-21

    This report describes the emissions of airborne radionuclides from operations at Los Alamos National Laboratory (LANL) for calendar year 2014, and the resulting off-site dose from these emissions. This document fulfills the requirements established by the National Emissions Standards for Hazardous Air Pollutants in 40 CFR 61, Subpart H – Emissions of Radionuclides other than Radon from Department of Energy Facilities, commonly referred to as the Radionuclide NESHAP or Rad-NESHAP. Compliance with this regulation and preparation of this document is the responsibility of LANL’s RadNESHAP compliance program, which is part of the Environmental Protection Division. The information in this report is required under the Clean Air Act and is being submitted to the U.S. Environmental Protection Agency (EPA) Region 6.

  8. Radionuclide migration as a function of mineralogy

    SciTech Connect

    Triay, I.R.; Mitchell, A.J.; Ott, M.A.

    1991-02-01

    The migration of radionuclides is studied as a function of mineralogy utilizing batch sorption and column experiments. The transport behavior of alkaline, alkaline-earth, and transition metals, and actinide species is studied in pure mineral separates. The solid phases utilized for these investigations are silicates, alumino-silicates, carbonates, and metal oxides and oxyhydroxides. The results of this effort are utilized to aid in the elucidation of the dominant chemical mechanisms of radionuclide migration, the prediction of radionuclide transport in conditions similar to those expected at the proposed high-level nuclear waste repository at Yucca Mountain, Nevada, and the identification of materials that act as natural geological barriers or that can be utilized as strong sorbers in engineered barriers. 9 refs., 2 figs., 2 tabs.

  9. Diffusion of Radionuclides in Concrete and Soil

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Bovaird, Chase C.; Parker, Kent E.; Recknagle, Kurtis P.; Clayton, Libby N.; Wood, Marcus I.

    2012-04-25

    One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Such concrete encasement would contain and isolate the waste packages from the hydrologic environment and would act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface environment. Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. The objective of our study was to measure the diffusivity of Re, Tc and I in concrete containment and the surrounding vadose zone soil. Effects of carbonation, presence of metallic iron, and fracturing of concrete and the varying moisture contents in soil on the diffusivities of Tc and I were evaluated.

  10. Therapeutic radionuclides: Making the right choice

    SciTech Connect

    Srivastava, S.C.

    1996-08-01

    Recently, there has been a resurgence of interest in nuclear medicine therapeutic procedures. Using unsealed sources for therapy is not a new concept; it has been around since the beginnings of nuclear medicine. Treatment of thyroid disorders with radioiodine is a classic example. The availability of radionuclides with suitable therapeutic properties for specific applications, as well as methods for their selective targeting to diseased tissue have, however, remained the main obstacles for therapy to assume a more widespread role in nuclear medicine. Nonetheless, a number of new techniques that have recently emerged, (e.g., tumor therapy with radiolabeled monoclonal antibodies, treatment of metastatic bone pain, etc.) appear to have provided a substantial impetus to research on production of new therapeutic radionuclides. Although there are a number of new therapeutic approaches requiring specific radionuclides, only selected broad areas will be used as examples in this article.

  11. Radioimmunotherapy with alpha-particle emitting radionuclides.

    PubMed

    Zalutsky, M R; Pozzi, O R

    2004-12-01

    An important consideration in the development of effective strategies for radioimmunotherapy is the nature of the radiation emitted by the radionuclide. Radionuclides decaying by the emission of alpha-particles offer the possibility of matching the cell specific reactivity of monoclonal antibodies with radiation with a range of only a few cell diameters. Furthermore, alpha-particles have important biological advantages compared with external beam radiation and beta-particles including a higher biological effectiveness, which is nearly independent of oxygen concentration, dose rate and cell cycle position. In this review, the clinical settings most likely to benefit from alpha-particle radioimmunotherapy will be discussed. The current status of preclinical and clinical research with antibodies labeled with 3 promising alpha-particle emitting radionuclides - (213)Bi, (225)Ac, and (211)At - also will be summarized.

  12. Therapeutic Radionuclides: Biophysical and Radiobiologic Principles

    PubMed Central

    Kassis, Amin I.

    2008-01-01

    Although the general radiobiologic principles underlying external beam therapy and radionuclide therapy are the same, there are significant differences in the biophysical and radiobiologic effects from the two types of radiation. In addition to the emission of particulate radiation, targeted radionuclide therapy is characterized by (i) extended exposures and, usually, declining dose rates; (ii) nonuniformities in the distribution of radioactivity and, thus, absorbed dose; and (iii) particles of varying ionization density and, hence, quality. This chapter explores the special features that distinguish the biologic effects consequent to the traversal of charged particles through mammalian cells. It also highlights what has been learned when these radionuclides and radiotargeting pharmaceuticals are used to treat cancers. PMID:18662557

  13. Data Authentication Demonstration for Radionuclide Stations

    SciTech Connect

    Harris, Mark; Herrington, Pres; Miley, Harry; Ellis, J. Edward; McKinnon, David; St. Pierre, Devon

    1999-08-03

    Data authentication is required for certification of sensor stations in the International Monitoring System (IMS). Authentication capability has been previously demonstrated for continuous waveform stations (seismic and infrasound). This paper addresses data surety for the radionuclide stations in the IMS, in particular the Radionuclide Aerosol Sampler/Analyzer (RASA) system developed by Pacific Northwest National Laboratory (PNNL). Radionuclide stations communicate data by electronic mail using formats defined in IMS 1.0, Formats and Protocols for Messages. An open message authentication standard exists, called S/MIME (Secure/Multipurpose Internet Mail Extensions), which has been proposed for use with all IMS radionuclide station message communications. This standard specifies adding a digital signature and public key certificate as a MIME attachment to the e-mail message. It is advantageous because it allows authentication to be added to all IMS 1.0 messages in a standard format and is commercially supported in e-mail software. For command and control, the RASA system uses a networked Graphical User Interface (GUI) based upon Common Object Request Broker Architecture (CORBA) communications, which requires special authentication procedures. The authors have modified the RASA system to meet CTBTO authentication guidelines, using a FORTEZZA card for authentication functions. They demonstrated signing radionuclide data messages at the RASA, then sending, receiving, and verifying the messages at a data center. They demonstrated authenticating command messages and responses from the data center GUI to the RASA. Also, the particular authentication system command to change the private/public key pair and retrieve the new public key was demonstrated. This work shows that data surety meeting IMS guidelines may be immediately applied to IMS radionuclide systems.

  14. GPU-accelerated voxelwise hepatic perfusion quantification.

    PubMed

    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.

  15. Effect of beam hardening on transmural myocardial perfusion quantification in myocardial CT imaging

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    The detection of subendocardial ischemia exhibiting an abnormal transmural perfusion gradient (TPG) may help identify ischemic conditions due to micro-vascular dysfunction. We evaluated the effect of beam hardening (BH) artifacts on TPG quantification using myocardial CT perfusion (CTP). We used a prototype spectral detector CT scanner (Philips Healthcare) to acquire dynamic myocardial CTP scans in a porcine ischemia model with partial occlusion of the left anterior descending (LAD) coronary artery guided by pressure wire-derived fractional flow reserve (FFR) measurements. Conventional 120 kVp and 70 keV projection-based mono-energetic images were reconstructed from the same projection data and used to compute myocardial blood flow (MBF) using the Johnson-Wilson model. Under moderate LAD occlusion (FFR~0.7), we used three 5 mm short axis slices and divided the myocardium into three LAD segments and three remote segments. For each slice and each segment, we characterized TPG as the mean "endo-to-epi" transmural flow ratio (TFR). BH-induced hypoenhancement on the ischemic anterior wall at 120 kVp resulted in significantly lower mean TFR value as compared to the 70 keV TFR value (0.29+/-0.01 vs. 0.55+/-0.01 p<1e-05). No significant difference was measured between 120 kVp and 70 keV mean TFR values on segments moderately affected or unaffected by BH. In the entire ischemic LAD territory, 120 kVp mean endocardial flow was significantly reduced as compared to mean epicardial flow (15.80+/-10.98 vs. 40.85+/-23.44 ml/min/100g; p<1e-04). At 70 keV, BH was effectively minimized resulting in mean endocardial MBF of 40.85+/-15.3407 ml/min/100g vs. 74.09+/-5.07 ml/min/100g (p=0.0054) in the epicardium. We also found that BH artifact in the conventional 120 kVp images resulted in falsely reduced MBF measurements even under non-ischemic conditions.

  16. beta-Hydroxy fatty acid production by ischemic rabbit heart.

    PubMed Central

    Moore, K H; Koen, A E; Hull, F E

    1982-01-01

    beta-Hydroxymyristate, -palmitate, and -stearate were produced by and accumulated in isolated rabbit heart when perfused ischemically for 2-10 min by the nonrecirculating langendorff technique with 0.75 mM palmitate and 0.16 mM albumin. Tissue fractionation into mitochondria and cytosol showed that by 2 min of ischemia 44% of beta-hydroxypalmitate and 38% beta-hydroxystearate was located in the cytosol; this percentage increased to greater than 50% by 5 min of ischemia. Lipid fractionation studies showed that by 10 min these two beta-hydroxy fatty acids were distributed approximately as 60% acylcarnitine, 20% acyl-coenzyme A (CoA), and 20% free fatty acids. All three chemical forms of beta-hydroxypalmitate were found in both the mitochondria and the cytosol. After 10 min of ischemia beta-hydroxypalmitoyl-CoA and beta-hydroxystearoyl-CoA constituted at least 16% of the incremental long-chain acyl-CoA, whereas beta-hydroxypalmitoylcarnitine and b-hydroxystearoylcarnitine constituted 8% of the incremental long-chain acylcarnitine. These data suggests that myocardial beta-hydroxyacyl-CoA oxidation is limited during ischemia. Substrate accumulates and is transferred to the cytosol where it accumulates primarily as beta-hydroxyacylcarnitine. PMID:6799549

  17. Lasers in the treatment of ischemic heart disease in China

    NASA Astrophysics Data System (ADS)

    Zhang, Yongzhen; Chen, Mingzhe

    2000-10-01

    Myocardial revascularization by laser is a new treatment modality for chronic, severe, refractory angina in the patients with coronary heart disease that is not amenable to angioplasty (PTCA) or bypass surgery (CABG). Transmyocardial revascularization (TMR), typically requiring open thoracotomy, uses laser to create channels that would directly carry blood from left ventricular cavity into the ischemic myocardium. Current data indicate that TMR may provide these patients with improvement in angina severity, quality of life, and myocardial perfusion. The greatest potential future use of TMR is as an adjunct to CABG in patients with disease that prevents bypass grafting due to lack of distal targets or a conduit. Recently, as percutaneous (catheter-based) myocardial revascularization (PMR) has been developed with laser technology that permits the creation of channels from the endocardial surface of the left ventricle. The early results with PMR seem encouraging. Randomized clinical trial has demonstrated symptomatic improvement and increased exercise capacity. The risk: benefit ratio for PMR appears to be much more favorable than that for TMR. The mechanisms of action of them have not yet been clearly elucidated, and several theories have been proposed, including channel patency, angiogenesis, denervation, and placebo effect. The challenge of TMR/PMR is related to improvement of perioperative outcomes and long-term survival without worsening of left ventricular function. In future, it may be feasible to combine TMR/PMR with intramyocardial delivery of angiogenic growth factors to induce further new blood vessel formation.

  18. The role of endoglin in post-ischemic revascularization.

    PubMed

    Núñez-Gómez, Elena; Pericacho, Miguel; Ollauri-Ibáñez, Claudia; Bernabéu, Carmelo; López-Novoa, José M

    2017-02-01

    Following arterial occlusion, blood vessels respond by forming a new network of functional capillaries (angiogenesis), by reorganizing preexisting capillaries through the recruitment of smooth muscle cells to generate new arteries (arteriogenesis) and by growing and remodeling preexisting collateral arterioles into physiologically relevant arteries (collateral development). All these processes result in the recovery of organ perfusion. The importance of endoglin in post-occlusion reperfusion is sustained by several observations: (1) endoglin expression is increased in vessels showing active angiogenesis/remodeling; (2) genetic endoglin haploinsufficiency in humans causes deficient angiogenesis; and (3) the reduction of endoglin expression by gene disruption or the administration of endoglin-neutralizing antibodies reduces angiogenesis and revascularization. However, the precise role of endoglin in the several processes associated with revascularization has not been completely elucidated and, in some cases, the function ascribed to endoglin by different authors is controversial. The purpose of this review is to organize in a critical way the information available for the role of endoglin in several phenomena (angiogenesis, arteriogenesis and collateral development) associated with post-ischemic revascularization.

  19. Nitroxyl exacerbates ischemic cerebral injury and oxidative neurotoxicity.

    PubMed

    Choe, Chi-un; Lewerenz, Jan; Fischer, Gerry; Uliasz, Tracy F; Espey, Michael Graham; Hummel, Friedhelm C; King, Stephen Bruce; Schwedhelm, Edzard; Böger, Rainer H; Gerloff, Christian; Hewett, Sandra J; Magnus, Tim; Donzelli, Sonia

    2009-09-01

    Nitroxyl (HNO) donor compounds function as potent vasorelaxants, improve myocardial contractility and reduce ischemia-reperfusion injury in the cardiovascular system. With respect to the nervous system, HNO donors have been shown to attenuate NMDA receptor activity and neuronal injury, suggesting that its production may be protective against cerebral ischemic damage. Hence, we studied the effect of the classical HNO-donor, Angeli's salt (AS), on a cerebral ischemia/reperfusion injury in a mouse model of experimental stroke and on related in vitro paradigms of neurotoxicity. I.p. injection of AS (40 mumol/kg) in mice prior to middle cerebral artery occlusion exacerbated cortical infarct size and worsened the persistent neurological deficit. AS not only decreased systolic blood pressure, but also induced systemic oxidative stress in vivo indicated by increased isoprostane levels in urine and serum. In vitro, neuronal damage induced by oxygen-glucose-deprivation of mature neuronal cultures was exacerbated by AS, although there was no direct effect on glutamate excitotoxicity. Finally, AS exacerbated oxidative glutamate toxicity - that is, cell death propagated via oxidative stress in immature neurons devoid of ionotropic glutamate receptors. Taken together, our data indicate that HNO might worsen cerebral ischemia-reperfusion injury by increasing oxidative stress and decreasing brain perfusion at concentrations shown to be cardioprotective in vivo.

  20. Laboratory studies of radionuclide migration in tuff

    SciTech Connect

    Rundberg, R.S.; Mitchell, A.J.; Ott, M.A.; Thompson, J.L.; Triay, I.R.

    1989-10-01

    The movement of selected radionuclides has been observed in crushed tuff, intact tuff, and fractured tuff columns. Retardation factors and dispersivities were determined from the elution profiles. Retardation factors have been compared with those predicted on the basis of batch sorption studies. This comparison forms a basis for either validating distribution coefficients or providing evidence of speciation, including colloid formation. Dispersivities measured as a function of velocity provide a means of determining the effect of sorption kinetics or mass transfer on radionuclide migration. Dispersion is also being studied in the context of scaling symmetry to develop a basis for extrapolating from the laboratory scale to the field. 21 refs., 6 figs., 2 tabs.

  1. Radionuclide imaging of the urinary tract

    SciTech Connect

    Velchik, M.G.

    1985-11-01

    This article describes the role of nuclear medicine in the evaluation of the genitourinary tract. The technical aspects of radionuclide imaging (radiopharmaceuticals, radiation dosimetry, instrumentation, and method) are briefly presented, and each of the indications for renal scintigraphy--including the evaluation of differential renal function, hypertension, obstruction, renal transplants, masses, trauma, congenital anomalies, vesicoureteral reflux, and infection--are discussed. The relative advantages and disadvantages of radionuclide imaging with respect to alternative radiographic examinations (such as intravenous urography, ultrasonography, CT, angiography, and magnetic resonance imaging) are emphasized wherever applicable. 136 references.

  2. Radionuclide imaging of the urinary tract.

    PubMed

    Velchik, M G

    1985-11-01

    This article describes the role of nuclear medicine in the evaluation of the genitourinary tract. The technical aspects of radionuclide imaging (radiopharmaceuticals, radiation dosimetry, instrumentation, and method) are briefly presented, and each of the indications for renal scintigraphy--including the evaluation of differential renal function, hypertension, obstruction, renal transplants, masses, trauma, congenital anomalies, vesicoureteral reflux, and infection--are discussed. The relative advantages and disadvantages of radionuclide imaging with respect to alternative radiographic examinations (such as intravenous urography, ultrasonography, CT, angiography, and magnetic resonance imaging) are emphasized wherever applicable.

  3. External accumulation of radionuclide in hepatic hydrothorax

    SciTech Connect

    Albin, R.J.; Johnston, G.S.

    1989-05-01

    Hepatic hydrothorax is a complication in approximately 5% of patients with cirrhosis. Ascites is almost always present and helps to suggest the correct diagnosis. However, when ascites is absent, radionuclide imaging has proven to be helpful in establishing that the pleural effusion originated from ascitic fluid. When pleural fluid is rapidly removed, such as by thoracostomy tube drainage, the radioisotope may accumulate outside the thorax and produce a negative scan of the chest. When the radionuclide scan is nondiagnostic and the pleural space is being rapidly drained, the pleural fluid collecting system should always be imaged before rejecting a diagnosis of hepatic hydrothorax.

  4. The Watchboy Radionuclide Detector Deployment and Analysis

    SciTech Connect

    Dazeley, S.; Bernstein, A.; Bowden, N.

    2014-09-30

    The Watchboy detector was designed to measure the rate of radionuclide production in water created via muon spallation. The three primary nuclei of interest, 11Li, 8He and 9Li, can mimic an antineutrino induced inverse beta decay, producing a high energy beta particle in coincidence with a neutron. Their signature in Watchboy would be the passage of a muon through the target, followed some time later, characterized by the decay time of the radionuclide, by a beta and a neutron emitted in coincidence.

  5. Endothelial colony forming cells and mesenchymal progenitor cells form blood vessels and increase blood flow in ischemic muscle.

    PubMed

    Kang, Kyu-Tae; Lin, Ruei-Zeng; Kuppermann, David; Melero-Martin, Juan M; Bischoff, Joyce

    2017-04-10

    Here we investigated whether endothelial colony forming cells (ECFC) and mesenchymal progenitor cells (MPC) form vascular networks and restore blood flow in ischemic skeletal muscle, and whether host myeloid cells play a role. ECFC + MPC, ECFC alone, MPC alone, or vehicle alone were injected into the hind limb ischemic muscle one day after ligation of femoral artery and vein. At day 5, hind limbs injected with ECFC + MPC showed greater blood flow recovery compared with ECFC, MPC, or vehicle. Tail vein injection of human endothelial specific Ulex europaeus agglutinin-I demonstrated an increased number of perfused human vessels in ECFC + MPC compared with ECFC. In vivo bioluminescence imaging showed ECFC persisted for 14 days in ECFC + MPC-injected hind limbs. Flow cytometric analysis of ischemic muscles at day 2 revealed increased myeloid lineage cells in ECFC + MPC-injected muscles compared to vehicle-injected muscles. Neutrophils declined by day 7, while the number of myeloid cells, macrophages, and monocytes did not. Systemic myeloid cell depletion with anti-Gr-1 antibody blocked the improved blood flow observed with ECFC + MPC and reduced ECFC and MPC retention. Our data suggest that ECFC + MPC delivery could be used to reestablish blood flow in ischemic tissues, and this may be enhanced by coordinated recruitment of host myeloid cells.

  6. Enhanced potency of cell-based therapy for ischemic tissue repair using an injectable bioactive epitope presenting nanofiber support matrix.

    PubMed

    Tongers, Jörn; Webber, Matthew J; Vaughan, Erin E; Sleep, Eduard; Renault, Marie-Ange; Roncalli, Jerome G; Klyachko, Ekaterina; Thorne, Tina; Yu, Yang; Marquardt, Katja-Theres; Kamide, Christine E; Ito, Aiko; Misener, Sol; Millay, Meredith; Liu, Ting; Jujo, Kentaro; Qin, Gangjian; Losordo, Douglas W; Stupp, Samuel I; Kishore, Raj

    2014-09-01

    The translation of cell-based therapies for ischemic tissue repair remains limited by several factors, including poor cell survival and limited target site retention. Advances in nanotechnology enable the development of specifically designed delivery matrices to address these limitations and thereby improve the efficacy of cell-based therapies. Given the relevance of integrin signaling for cellular homeostasis, we developed an injectable, bioactive peptide-based nanofiber matrix that presents an integrin-binding epitope derived from fibronectin, and evaluated its feasibility as a supportive artificial matrix for bone marrow-derived pro-angiogenic cells (BMPACs) used as a therapy in ischemic tissue repair. Incubation of BMPACs with these peptide nanofibers in vitro significantly attenuated apoptosis while enhancing proliferation and adhesion. Pro-angiogenic function was enhanced, as cells readily formed tubes. These effects were, in part, mediated via p38, and p44/p42 MAP kinases, which are downstream pathways of focal adhesion kinase. In a murine model of hind limb ischemia, an intramuscular injection of BMPACs within this bioactive peptide nanofiber matrix resulted in greater retention of cells, enhanced capillary density, increased limb perfusion, reduced necrosis/amputation, and preserved function of the ischemic limb compared to treatment with cells alone. This self-assembling, bioactive peptide nanofiber matrix presenting an integrin-binding domain of fibronectin improves regenerative efficacy of cell-based strategies in ischemic tissue by enhancing cell survival, retention, and reparative functions.

  7. Radionuclide scrotal imaging: further experience with 210 patients. Part I. Anatomy, pathophysiology, and methods

    SciTech Connect

    Chen, D.C.P.; Holder, L.E.; Melloul, M.

    1983-08-01

    Ten years' experience with radionuclide scrotal imaging (RSI) to evaluate perfusion of the scrotal contents has confirmed the value of this examination. In 1973, Nadel et al. first proposed using sodium pertechnetate (Tc-99m) to diagnose testicular torsion. By the end of 1982, more than thirty articles have been published on this topic, with most emphasizing the usefulness of RSI in managing patients with acute scrotal pain. The present communication describes our findings in 210 patients, not previously reported. There were four groups with relatively distinct clinical presentations: (a) acute scrotal pain, (b) chronic scrotal pain, (c) scrotal injury, and (d) scrotal mass. The anatomic and pathophysiologic bases for the scan findings will be emphasized. We discuss the staging of testicular torsion; viability of the compromised testicle; variability in the presentation of acute infection; anatomy of trauma, varicocele, and inguinal hernia; and the correlation with scrotal sonography.

  8. Assessment of Radionuclides in the Savannah River Site Environment Summary

    SciTech Connect

    Carlton, W.H.

    1999-01-26

    This document summarizes the impact of radionuclide releases from Savannah River Site (SRS) facilities from 1954 through 1996. The radionuclides reported here are those whose release resulted in the highest dose to people living near SRS.

  9. Monitoring stroke progression: in vivo imaging of cortical perfusion, blood-brain barrier permeability and cellular damage in the rat photothrombosis model.

    PubMed

    Schoknecht, Karl; Prager, Ofer; Vazana, Udi; Kamintsky, Lyn; Harhausen, Denise; Zille, Marietta; Figge, Lena; Chassidim, Yoash; Schellenberger, Eyk; Kovács, Richard; Heinemann, Uwe; Friedman, Alon

    2014-11-01

    Focal cerebral ischemia is among the main causes of death and disability worldwide. The ischemic core often progresses, invading the peri-ischemic brain; however, assessing the propensity of the peri-ischemic brain to undergo secondary damage, understanding the underlying mechanisms, and adjusting treatment accordingly remain clinically unmet challenges. A significant hallmark of the peri-ischemic brain is dysfunction of the blood-brain barrier (BBB), yet the role of disturbed vascular permeability in stroke progression is unclear. Here we describe a longitudinal in vivo fluorescence imaging approach for the evaluation of cortical perfusion, BBB dysfunction, free radical formation and cellular injury using the photothrombosis vascular occlusion model in male Sprague Dawley rats. Blood-brain barrier dysfunction propagated within the peri-ischemic brain in the first hours after photothrombosis and was associated with free radical formation and cellular injury. Inhibiting free radical signaling significantly reduced progressive cellular damage after photothrombosis, with no significant effect on blood flow and BBB permeability. Our approach allows a dynamic follow-up of cellular events and their response to therapeutics in the acutely injured cerebral cortex.

  10. Identification of ischemic and hibernating myocardium: feasibility of post-exercise F-18 deoxyglucose positron emission tomography

    SciTech Connect

    Marwick, T.H.; MacIntyre, W.J.; Salcedo, E.E.; Go, R.T.; Saha, G.; Beachler, A. )

    1991-02-01

    The identification of ischemic and hibernating myocardium facilitates the selection of patients most likely to benefit from revascularization. This study examined the feasibility of metabolic imaging, using post-exercise F-18 deoxyglucose positron emission tomography (FDG-PET) for the diagnosis of both ischemia and hibernation in 27 patients with known coronary anatomy. Normal post-exercise FDG uptake was defined in each patient by reference to normal resting perfusion and normal coronary supply. Abnormal elevation of FDG (ischemia or hibernation) was compared in 13 myocardial segments in each patient, with the results of dipyridamole stress perfusion imaging performed by rubidium-82 positron emission tomography (Rb-PET). Myocardial ischemia was diagnosed by either FDG-PET or Rb-PET in 34 segments subtended by significant local coronary stenoses. Increased FDG uptake was present in 32/34 (94%) and a reversible perfusion defect was identified by Rb-PET in 22/34 (65%, p less than .01). In 3 patients, ischemia was identified by metabolic imaging alone. In 16 patients with previous myocardial infarction, perfusion defects were present at rest in 89 regions, 30 of which (34%) demonstrated increased FDG uptake, consistent with the presence of hibernation. Increased post-exercise FDG uptake appears to be a sensitive indicator of ischemia and myocardial hibernation. Increased post-exercise FDG uptake, appears to be a sensitive indicator of ischemia and myocardial hibernation. This test may be useful in selecting post-infarction patients for revascularization.

  11. Diluted Blood Reperfusion as a Model for Transplantation of Ischemic Rat Livers: ALT is a Direct Indicator of Viability

    PubMed Central

    Uygun, Korkut; Tolboom, Herman; Izamis, Maria-Louisa; Uygun, Basak; Sharma, Nripen; Yagi, Hiroshi; Soto-Gutierrez, Alejandro; Hertl, Martin; Berthiaume, François; Yarmush, Martin L.

    2010-01-01

    Donors after Cardiac Death present a significant pool of untapped organs for transplantation, and use of machine perfusion strategies has been an active focus area in experimental transplantation. However, despite two decades of research, a gold standard is yet to emerge for machine perfusion systems and protocols. Whole blood reperfusion has been used as a surrogate for organ transplantation, especially as a model for the short-term response post transplantation, for optimization of perfusion systems. While it is known that there is a strong correlation between liver function in whole-blood reperfusion and survival, the exact nature of these correlations, and to what extent they can be considered as an indicator of viability for transplantation/recipient survival, remain unclear. In this work, we demonstrate that diluted whole-blood reperfusion can be used as a direct model for transplantation of ischemic rat liver grafts. Moreover, it was shown that recipient survival can be predicted based simply on the value of ALT during perfusion, and quantitative criteria of viability was developed for use in this animal model. These results indicate that in the rat model graft survival is highly correlated to hepatocellular damage. PMID:20832525

  12. Comparison of exercise radionuclide angiography with thallium SPECT imaging for detection of significant narrowing of the left circumflex coronary artery

    SciTech Connect

    Dilsizian, V.; Perrone-Filardi, P.; Cannon, R.O. 3d.; Freedman, N.M.; Bacharach, S.L.; Bonow, R.O. )

    1991-08-01

    Although quantitation of exercise thallium tomograms has enhanced the noninvasive diagnosis and localization of coronary artery disease, the detection of stenosis of the left circumflex coronary artery remains suboptimal. Because posterolateral regional wall motion during exercise is well assessed by radionuclide angiography, this study determined whether regional dysfunction of the posterolateral wall during exercise radionuclide angiography is more sensitive in identifying left circumflex disease than thallium perfusion abnormalities assessed by single-photon emission computed tomography (SPECT). One hundred ten consecutive patients with CAD were studied, of whom 70 had a significant stenosis of the left circumflex coronary artery or a major obtuse marginal branch. Both regional function and segmental thallium activity of the posterolateral wall were assessed using visual and quantitative analysis. Left ventricular regional function was assessed objectively by dividing the left ventricular region of interest into 20 sectors; the 8 sectors corresponding to the posterolateral free wall were used to assess function in the left circumflex artery distribution. Similarly, using circumferential profile analysis of short-axis thallium tomograms, left ventricular myocardial activity was subdivided into 64 sectors; the 16 sectors corresponding to the posterolateral region were used to assess thallium perfusion abnormalities in the left circumflex artery territory. Qualitative posterolateral wall motion analysis detected 76% of patients with left circumflex coronary artery stenosis, with a specificity of 83%, compared with only 44% by qualitative thallium tomography (p less than 0.001) and a specificity of 92%.

  13. 21 CFR 892.5750 - Radionuclide radiation therapy system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radionuclide radiation therapy system. 892.5750... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5750 Radionuclide radiation therapy system. (a) Identification. A radionuclide radiation therapy system is a device intended to permit...

  14. 21 CFR 892.5700 - Remote controlled radionuclide applicator system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Remote controlled radionuclide applicator system. 892.5700 Section 892.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radionuclide applicator system. (a) Identification. A remote controlled radionuclide applicator system is...

  15. 21 CFR 892.5700 - Remote controlled radionuclide applicator system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Remote controlled radionuclide applicator system. 892.5700 Section 892.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radionuclide applicator system. (a) Identification. A remote controlled radionuclide applicator system is...

  16. 21 CFR 892.5700 - Remote controlled radionuclide applicator system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Remote controlled radionuclide applicator system. 892.5700 Section 892.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radionuclide applicator system. (a) Identification. A remote controlled radionuclide applicator system is...

  17. 21 CFR 892.5700 - Remote controlled radionuclide applicator system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Remote controlled radionuclide applicator system. 892.5700 Section 892.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radionuclide applicator system. (a) Identification. A remote controlled radionuclide applicator system is...

  18. Myocardial perfusion scintigraphy: the evidence

    PubMed Central

    Anagnostopoulos, C.; Cerqueira, M.; Ell, P. J.; Flint, E. J.; Harbinson, M.; Kelion, A. D.; Al-Mohammad, A.; Prvulovich, E. M.; Shaw, L. J.; Tweddel, A. C.

    2003-01-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by

  19. Understanding Radionuclide Interactions with Layered Materials

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2015-12-01

    Layered materials play an important role in nuclear waste management and environmental cleanup. Better understanding of radionuclide interactions with those materials is critical for engineering high-performance materials for various applications. This presentation will provide an overview on radionuclide interactions with two general categories of layered materials - cationic clays and anionic clays - from a perspective of nanopore confinement. Nanopores are widely present in layered materials, either as the interlayers or as inter-particle space. Nanopore confinement can significantly modify chemical reactions in those materials. This effect may cause the preferential enrichment of radionuclides in nanopores and therefore directly impact the mobility of the radionuclides. This effect also implies that conventional sorption measurements using disaggregated samples may not represent chemical conditions in actual systems. The control of material structures on ion exchange, surface complexation, and diffusion in layered materials will be systematically examined, and the related modeling approaches will be discussed. This work was performed at Sandia National Laboratories, which is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the DOE under contract DE-AC04-94AL8500.

  20. REMOVAL OF RADIONUCLIDES BY ELECTROKINETIC SOIL PROCESSING

    EPA Science Inventory

    Electrokinetics promises to be an innovative treatment process for in-situ treatment of soils and groundwater contaminated with heavy metals and radionuclides. Electrokinetics refers to the movement of ionic liquids and charged particles relative to one another under the action ...

  1. RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

    SciTech Connect

    S. Magnuson

    2004-11-01

    The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.

  2. Cardiac tissue engineering using perfusion bioreactor systems

    PubMed Central

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  3. Histopathologic studies of ischemic optic neuropathy.

    PubMed Central

    Knox, D L; Kerrison, J B; Green, W R

    2000-01-01

    PURPOSE: To define the histopathologic features of eyes in which a pathologic diagnosis of ischemic optic neuropathy had been made in the years 1951 through 1998. METHODS: The following data were documented: age of patient, race, sex, source of tissue, cause of death, clinical history, interval from loss of vision to death, enucleation, exenteration, and biopsy. The histopathologic criteria for diagnosis of ischemic optic neuropathy were the presence of localized ischemic edema, cavernous degeneration, or an area of atrophy located superior or inferior in the optic nerve. Cases with history of abrupt loss of vision were combined with reports from the literature to construct a time table of histopathologic features and associated conditions. RESULTS: Ischemic optic neuropathy was present in 193 eyes. There were 88 females and 65 males. The average age was 71.6 years. Ischemic edema without (early) and with (later) gitter macrophages was present in 26 (13.5%). Cavernous degeneration was present in 69 nerves (36%). Mucopolysaccharide (MPS) was present in 37 cavernous lesions 1 month or longer after loss of vision. Cavernous lesions were seen in 3 eyes in which peripapillary retinal nerve fiber layer hemorrhage had been observed prior to death. Atrophic lesions, the most common pattern, were observed in 133 optic nerves (66.8%). More than 1 ischemic lesion was seen in 38 optic nerves (19.7%). Bilateral ischemic lesions were seen in 50 (35.2%) of 142 paired eyes. CONCLUSIONS: Ischemic optic nerve lesions are initially acellular and later show macrophage infiltration. Cavernous lesions with MPS are present 4 weeks or longer after vision loss. The location of MPS posteriorly and along the internal margin suggests that MPS is produced at the edges of lesions. Progressive vision loss in ischemic optic neuropathy may be secondary to compression of intact nerve from ischemic edema and cavernous swelling, or a second ischemic lesion. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5

  4. Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.

    1982-12-01

    SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides (/sup 137/Cs, /sup 90/Sr, /sup 239/ /sup 240/Pu, and /sup 3/H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay.

  5. Angiogenic Mechanisms of Human CD34(+) Stem Cell Exosomes in the Repair of Ischemic Hindlimb.

    PubMed

    Mathiyalagan, Prabhu; Liang, Yaxuan; Kim, David; Misener, Sol; Thorne, Tina; Kamide, Christine; Klyachko, Ekaterina; Losordo, Douglas W; Hajjar, Roger J; Sahoo, Susmita

    2017-03-15

    Rationale: Paracrine secretions appear to mediate therapeutic effects of human CD34(+) stem cells locally transplanted in patients with myocardial and critical limb ischemia as well as in animal models. Earlier, we had discovered that paracrine secretion from human CD34(+) cells contains pro-angiogenic, membrane-bound nano-vesicles called exosomes (CD34Exo). Objective: Here, we investigated the mechanisms of CD34Exo-mediated ischemic tissue repair and therapeutic angiogenesis by studying their miRNA content and uptake. Methods and Results: When injected into mouse ischemic hindlimb tissue, CD34Exo, but not the CD34exo-depleted conditioned media, mimicked the beneficial activity of their parent cells by improving ischemic limb perfusion, capillary density, motor function and their amputation. CD34Exo were found to be enriched with pro-angiogenic miRNAs such as miR-126-3p. Knocking down miR-126-3p from CD34exo abolished their angiogenic activity and beneficial function both in vitro and in vivo. Interestingly, injection of CD34Exo increased miR-126-3p levels in mouse ischemic limb, but did not affect the endogenous synthesis of miR-126-3p suggesting a direct transfer of stable and functional exosomal miR-126-3p. miR-126-3p enhanced angiogenesis by suppressing the expression of its known target, SPRED1; simultaneously modulating the expression of genes involved in angiogenic pathways such as VEGF, ANG1, ANG2, MMP9, TSP1 etc. Interestingly, CD34Exo, when treated to ischemic hindlimbs, were most efficiently internalized by endothelial cells relative to smooth muscle cells and fibroblasts demonstrating a direct role of stem cell-derived exosomes on mouse endothelium at the cellular level. Conclusions: Collectively, our results have demonstrated a novel mechanism by which cell-free CD34Exo mediates ischemic tissue repair via beneficial angiogenesis. Exosome-shuttled angiomiRs may signify amplification of stem cell function and may explain the angiogenic and therapeutic

  6. Normothermic Machine Perfusion of Deceased Donor Liver Grafts Is Associated With Improved Postreperfusion Hemodynamics

    PubMed Central

    Angelico, Roberta; Perera, M. Thamara P. R; Ravikumar, Reena; Holroyd, David; Coussios, Constantin; Mergental, Hynek; Isaac, John R.; Iqbal, Asim; Cilliers, Hentie; Muiesan, Paolo; Friend, Peter J.; Mirza, Darius F.

    2016-01-01

    Background Graft reperfusion poses a critical challenge during liver transplantation and can be associated with hemodynamic instability/postreperfusion syndrome. This is sequel to ischemia-reperfusion injury and normothermic machine preservation (NMP) may affect hemodynamic changes. Herein, we characterize postreperfusion hemodynamics in liver grafts after NMP and traditional cold preservation. Materials and methods Intraoperative records of patients receiving grafts after NMP (n = 6; NMP group) and cold storage (CS) (n = 12; CS group) were compared. The mean arterial pressure (MAP) was defined as the average pressure in the radial artery during 1 cardiac cycle by invasive monitoring. Postreperfusion syndrome was defined as MAP drop greater than 30% of baseline, lasting for 1 minute or longer within the first 5 minutes from graft reperfusion. Results Donor, recipient, demographics, and surgical parameters were evenly matched. Normothermic machine preservation grafts were perfused for 525 minutes (395-605 minutes) after initial cold ischemic time of 91 minutes (73-117 minutes), whereas in CS group cold ischemic time was 456 minutes (347-685 minutes) (P = 0.001). None developed postreperfusion syndrome in the NMP group against n = 2 (16.7%) in CS group (P = 0.529). Normothermic machine preservation group had better intraoperative MAP at 90 minutes postreperfusion (P = 0.029), achieved with a significantly less vasopressor requirement (P = <0.05) and less transfusion of blood products (P = 0.030) compared with CS group. Conclusions Normothermic machine perfusion is associated with a stable intraoperative hemodynamic profile postreperfusion, requiring significantly less vasopressor infusions and blood product transfusion after graft reperfusion and may have benefit to alleviate ischemia-reperfusion injury in liver transplantation. PMID:27795989

  7. Cerebral perfusion during canine hypothermic cardiopulmonary bypass: effect of arterial carbon dioxide tension.

    PubMed

    Johnston, W E; Vinten-Johansen, J; DeWitt, D S; O'Steen, W K; Stump, D A; Prough, D S

    1991-09-01

    Cerebral blood flow (radioactive microspheres), intracranial pressure (subdural bolt), and retinal histopathology were examined in 20 dogs undergoing 150 minutes of hypothermic (28 degrees C) cardiopulmonary bypass to compare alpha-stat (arterial carbon dioxide tension, 40 +/- 1 mm Hg; n = 10) and pH-stat (arterial carbon dioxide tension, 61 +/- 1 mm Hg; n = 10) techniques of arterial carbon dioxide tension management. Pump flow (80 mL.kg-1.min-1), mean aortic pressure (78 +/- 2 mm Hg), and hemoglobin level (87 +/- 3 g/L [8.7 +/- 0.3 g/dL]) were maintained constant. During bypass, intracranial pressure progressively increased in the alpha-stat group from 6.0 +/- 1.0 to 13.9 +/- 1.8 mm Hg (p less than 0.05) and in the pH-stat group from 7.7 +/- 1.1 to 14.7 +/- 1.4 mm Hg (p less than 0.05), although there was no evidence of loss of intracranial compliance or intracranial edema formation as assessed by brain water content. With cooling, cerebral blood flow decreased by 56% to 62% in the alpha-stat group (p less than 0.05) and by 48% to 56% in the pH-stat group (p less than 0.05). However, 30 minutes after rewarming to 37 degrees C, cerebral blood flow in both groups failed to increase and remained significantly depressed compared with baseline values. Both groups showed similar amounts of ischemic retinal damage, with degeneration of bipolar cells found in the inner nuclear layer in 67% of animals. We conclude that, independent of the arterial carbon dioxide tension management technique, (1) cerebral perfusion decreased comparably during prolonged hypothermic bypass, (2) intracranial pressure increases progressively, (3) ischemic damage to retinal cells occurs despite maintenance of aortic pressure and flow, and (4) a significant reduction in cerebral perfusion persists after rewarming.

  8. Normothermic ex vivo perfusion provides superior organ preservation and enables viability assessment of hearts from DCD donors.

    PubMed

    Iyer, A; Gao, L; Doyle, A; Rao, P; Cropper, J R; Soto, C; Dinale, A; Kumarasinghe, G; Jabbour, A; Hicks, M; Jansz, P C; Feneley, M P; Harvey, R P; Graham, R M; Dhital, K K; MacDonald, P S

    2015-02-01

    The shortage of donors in cardiac transplantation may be alleviated by the use of allografts from donation after circulatory death (DCD) donors. We have previously shown that hearts exposed to 30 min warm ischemic time and then flushed with Celsior supplemented with agents that activate ischemic postconditioning pathways, show complete recovery on a blood-perfused ex vivo working heart apparatus. In this study, these findings were assessed in a porcine orthotopic heart transplant model. DCD hearts were preserved with either normothermic ex vivo perfusion (NEVP) using a clinically approved device, or with standard cold storage (CS) for 4 h. Orthotopic transplantation into recipient animals was subsequently undertaken. Five of six hearts preserved with NEVP demonstrated favorable lactate profiles during NEVP and all five could be weaned off cardiopulmonary bypass posttransplant, compared with 0 of 3 hearts preserved with CS (p < 0.05, Fisher's exact test). In conclusion, DCD hearts flushed with supplemented Celsior solution and preserved with NEVP display viability before and after transplantation. Viability studies of human DCD hearts using NEVP are warranted.

  9. Labeling of monoclonal antibodies with radionuclides

    SciTech Connect

    Bhargava, K.K.; Acharya, S.A. )

    1989-07-01

    Antibodies, specifically monoclonal antibodies, are potentially very useful and powerful carriers of therapeutic agents to target tissues and diagnostic agents. The loading or charging of antibodies with agents, especially radiotracers, is reviewed here. The choice of radioisotope for immunodetection and/or immunotherapy is based on its availability, half-life, nature of the radiation emitted, and the metabolic pathways of the radionuclide in the body. Most important of all are the derivatization techniques available for labeling the antibody with the given radionuclide. Isotopes of iodine and divalent metal ions are the most commonly used radionuclides. Antibodies labeled with iodine at tyrosine residues are metabolized rapidly in vivo. This leads to the incorporation of metabolized radioactive iodine into various tissues, mainly the thyroid gland and stomach, and to the accumulation of high levels of circulating iodine in the blood, which masks tumor uptake considerably. To overcome these limitations, the use of iodohippurate as an iodine-anchoring molecule to the protein should be considered. When divalent or multivalent metal ions are used as the preferred radionuclide, bifunctional chelating reagents such as EDTA or DTPA are first coupled to the protein or antibody. These chelating molecules are attached to the protein by formation of an isopeptide linkage between the carboxylate of the chelating reagent and the amino group of the protein. Several procedures are available to generate the isopeptide linkage. When the anchoring of the chelating agent through isopeptide linkage results in the inactivation of the antibody, periodate oxidation of the carbohydrate moiety of the antibody, followed by reductive coupling of chelator, could be considered as an alternative. There is still a need for better, simpler, and more direct methods for labeling antibodies with radionuclides. 78 references.

  10. 2006 LANL Radionuclide Air Emissions Report

    SciTech Connect

    David P. Fuehne

    2007-06-30

    This report describes the impacts from emissions of radionuclides at Los Alamos National Laboratory (LANL) for calendar year 2006. This report fulfills the requirements established by the Radionuclide National Emissions Standards for Hazardous Air Pollutants (Rad-NESHAP). This report is prepared by LANL's Rad-NESHAP compliance team, part of the Environmental Protection Division. The information in this report is required under the Clean Air Act and is being reported to the U.S. Environmental Protection Agency (EPA). The highest effective dose equivalent (EDE) to an off-site member of the public was calculated using procedures specified by the EPA and described in this report. LANL's EDE was 0.47 mrem for 2006. The annual limit established by the EPA is 10 mrem per year. During calendar year 2006, LANL continuously monitored radionuclide emissions at 28 release points, or stacks. The Laboratory estimates emissions from an additional 58 release points using radionuclide usage source terms. Also, LANL uses a network of air samplers around the Laboratory perimeter to monitor ambient airborne levels of radionuclides. To provide data for dispersion modeling and dose assessment, LANL maintains and operates meteorological monitoring systems. From these measurement systems, a comprehensive evaluation is conducted to calculate the EDE for the Laboratory. The EDE is evaluated as any member of the public at any off-site location where there is a residence, school, business, or office. In 2006, this location was the Los Alamos Airport Terminal. The majority of this dose is due to ambient air sampling of plutonium emitted from 2006 clean-up activities at an environmental restoration site (73-002-99; ash pile). Doses reported to the EPA for the past 10 years are shown in Table E1.

  11. Syringe calibration factors for the NPL Secondary Standard Radionuclide Calibrator for selected medical radionuclides.

    PubMed

    Tyler, D K; Woods, M J

    2003-01-01

    Before a radiopharmaceutical is administered to a patient, its activity needs to be accurately assayed. This is normally done via a radionuclide calibrator, using a glass vial as the calibration device. The radionuclide is then transferred to a syringe and it is now becoming common practice to re-measure the syringe and use this value as the activity administered to the patient. Due to elemental composition and geometrical differences, etc. between the glass vial and the syringe, the calibration factors are different for the two containers and this can lead to an incorrect activity being given to the patient unless a correction is applied for these differences. To reduce the uncertainty on syringe measurements, syringe calibration factors and volume correction factors for the NPL Secondary Standard Radionuclide Calibrator have been derived by NPL for several medically important radionuclides. It was found that the differences between the calibration factors for the syringes and glass vials depend on the energies of the photon emissions from the decay of the radionuclides; the lower the energy, the greater the difference. As expected, large differences were observed for 125I (70%) and only small differences for 131I. However, for radionuclides such as 99mTc and 67Ga, differences of up to 30% have been observed. This work has shown the need for the use of specifically derived syringe calibration factors as well as highlighting the complexity of the problem with regard to syringe types, procurement, etc.

  12. Myocardial ischemic protection in natural mammalian hibernation.

    PubMed

    Yan, Lin; Kudej, Raymond K; Vatner, Dorothy E; Vatner, Stephen F

    2015-03-01

    Hibernating myocardium is an important clinical syndrome protecting the heart with chronic myocardial ischemia, named for its assumed resemblance to hibernating mammals in winter. However, the effects of myocardial ischemic protection have never been studied in true mammalian hibernation, which is a unique strategy for surviving extreme winter environmental stress. The goal of this investigation was to test the hypothesis that ischemic stress may also be protected in woodchucks as they hibernate in winter. Myocardial infarction was induced by coronary occlusion followed by reperfusion in naturally hibernating woodchucks in winter with and without hibernation and in summer, when not hibernating. The ischemic area at risk was similar among groups. Myocardial infarction was significantly less in woodchucks in winter, whether hibernating or not, compared with summer, and was similar to that resulting after ischemic preconditioning. Whereas several genes were up or downregulated in both hibernating woodchuck and with ischemic preconditioning, one mechanism was unique to hibernation, i.e., activation of cAMP-response element binding protein (CREB). When CREB was upregulated in summer, it induced protection similar to that observed in the woodchuck heart in winter. The cardioprotection in hibernation was also mediated by endothelial nitric oxide synthase, rather than inducible nitric oxide synthase. Thus, the hibernating woodchuck heart is a novel model to study cardioprotection for two major reasons: (1) powerful cardioprotection occurs naturally in winter months in the absence of any preconditioning stimuli, and (2) it resembles ischemic preconditioning, but with novel mechanisms, making this model potentially useful for clinical translation.

  13. Myocardial ischemic protection in natural mammalian hibernation

    PubMed Central

    Yan, Lin; Kudej, Raymond K.; Vatner, Dorothy E.

    2015-01-01

    Hibernating myocardium is an important clinical syndrome protecting the heart with chronic myocardial ischemia, named for its assumed resemblance to hibernating mammals in winter. However, the effects of myocardial ischemic protection have never been studied in true mammalian hibernation, which is a unique strategy for surviving extreme winter environmental stress. The goal of this investigation was to test the hypothesis that ischemic stress may also be protected in woodchucks as they hibernate in winter. Myocardial infarction was induced by coronary occlusion followed by reperfusion in naturally hibernating woodchucks in winter with and without hibernation and in summer, when not hibernating. The ischemic area at risk was similar among groups. Myocardial infarction was significantly less in woodchucks in winter, whether hibernating or not, compared with summer, and was similar to that resulting after ischemic preconditioning. Whereas several genes were up or downregulated in both hibernating woodchuck and with ischemic preconditioning, one mechanism was unique to hibernation, i.e., activation of cAMP-response element binding protein (CREB). When CREB was upregulated in summer, it induced protection similar to that observed in the woodchuck heart in winter. The cardioprotection in hibernation was also mediated by endothelial nitric oxide synthase, rather than inducible nitric oxide synthase. Thus, the hibernating woodchuck heart is a novel model to study cardioprotection for two major reasons: (1) powerful cardioprotection occurs naturally in winter months in the absence of any preconditioning stimuli, and (2) it resembles ischemic preconditioning, but with novel mechanisms, making this model potentially useful for clinical translation. PMID:25613166

  14. Ischemic brain injury in cerebral amyloid angiopathy

    PubMed Central

    van Veluw, Susanne J; Greenberg, Steven M

    2016-01-01

    Cerebral amyloid angiopathy (CAA) is a common form of cerebral small vessel disease and an important risk factor for intracerebral hemorrhage and cognitive impairment. While the majority of research has focused on the hemorrhagic manifestation of CAA, its ischemic manifestations appear to have substantial clinical relevance as well. Findings from imaging and pathologic studies indicate that ischemic lesions are common in CAA, including white-matter hyperintensities, microinfarcts, and microstructural tissue abnormalities as detected with diffusion tensor imaging. Furthermore, imaging markers of ischemic disease show a robust association with cognition, independent of age, hemorrhagic lesions, and traditional vascular risk factors. Widespread ischemic tissue injury may affect cognition by disrupting white-matter connectivity, thereby hampering communication between brain regions. Challenges are to identify imaging markers that are able to capture widespread microvascular lesion burden in vivo and to further unravel the etiology of ischemic tissue injury by linking structural magnetic resonance imaging (MRI) abnormalities to their underlying pathophysiology and histopathology. A better understanding of the underlying mechanisms of ischemic brain injury in CAA will be a key step toward new interventions to improve long-term cognitive outcomes for patients with CAA. PMID:25944592

  15. [Ocular ischemic syndrome--a case report].

    PubMed

    Zemba, M; Avram, Corina Ioana; Ochinciuc, Uliana; Stamate, Alina Cristina; Camburu, Raluca Lăcrămioara

    2013-01-01

    Ocular ischemic syndrome, also known as hypoperfusion/ hypotensive retinopathy or as ischemic oculopathy is a rare ocular disease determined by chronic arterial hypoperfusion through central retinal artery, posterior and anterior ciliary arteries. It is bilateral in 20% of the cases. Most often it appears due to severe occlusion of the carotid arteries (ICA, MCA>ECA), described in 1963 by Kearns and Hollenhorst. Occasionally it can be determined by the obstruction of ophtalmic artery or some arterities (Takayasu, giant cell arteritis). The risk factors are: age between 50-80 years, males (M:F = 2:1), arterial hypertension, diabetes, coronary diseases (5% of the cases develop ocular ischemic syndrome), vascular stroke, hemodialysis. The case we present is of an 63 years old man known with primary arterial hypertension, hypercholesterolemia, diabetes type 2 non insulin dependent and diagnosticated with ischemic cerebral stroke and bilateral obstruction of internal carotid arteries in march 2010, who is presenting for visual impairment in both eyes. The imaging investigations show important carotid occlusion and at the ophthalmologic evaluation there are ocular hypertension and rubeosis iridis at the right eye, optic atrophy at both eyes (complete in the right eye and partial in the left eye), with superior altitudinal visual field defect in left eye. The following diagnosis was established: Chronic ocular ischemic syndrome in both eyes with Neovascular glaucoma at the right eye, Anterior ischemic optic neuropathy at the left eye and laser panphotocoagulation at the right eye was started.

  16. Imaging of myocardial perfusion with magnetic resonance.

    PubMed

    Barkhausen, Jörg; Hunold, Peter; Jochims, Markus; Debatin, Jörg F

    2004-06-01

    Coronary artery disease (CAD) is currently the leading cause of death in developed nations. Reflecting the complexity of cardiac function and morphology, noninvasive diagnosis of CAD represents a major challenge for medical imaging. Although coronary artery stenoses can be depicted with magnetic resonance (MR) and computed tomography (CT) techniques, its functional or hemodynamic impact frequently remains elusive. Therefore, there is growing interest in other, target organ-specific parameters such as myocardial function at stress and first-pass myocardial perfusion imaging to assess myocardial blood flow. This review explores the pathophysiologic background, recent technical developments, and current clinical status of first-pass MR imaging (MRI) of myocardial perfusion.

  17. Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke

    PubMed Central

    Little, Philip; Kvist, Ola; Grankvist, Rikard; Jonsson, Stefan; Damberg, Peter; Söderman, Michael; Arnberg, Fabian; Holmin, Staffan

    2017-01-01

    Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury. PMID:28068417

  18. Relationship of brain imaging with radionuclides and with x-ray computed tomography

    SciTech Connect

    Kuhl, D.E.

    1981-03-03

    Because of high sensitivity and specificity for altered local cerebral structure, x-ray computed tomography (CT) is the preferred initial diagnostic imaging study under most circumstances when cerebral disease is suspected. CT has no competitor for detecting fresh intracerebral hemorrhage. Radionuclide imaging (RN) scan is preferred when relative perfusion is to be assessed, in patients allergic to contrast media, and when an adequate CT study is not technically possible. (RN) plays an important complementary role to CT, especially for patients suspected of subacute or chronic subdura hematoma, cerebral infarction, arteriovenous malformations, meningitis, encephalitis, normal pressure hydrocephalus, or when CT findings are inconclusive. When CT is not available, RN serves as a good screening study for suspected cerebral tumor, infection, recent infarction, arteriovenous malformation, and chronic subdural hematoma. Future improvement in radionuclide imaging by means of emission composition potential. The compound plating approacl threshold for all the investigated transistors and fast neutron spectra lies within the raal. The value of the potential slightly changes with the coordinate change in this region, i.e. the charge on a collecting electrode is not practically guided up to a certain moment of time during the movement of nonequilibrium carriers.

  19. Radionuclide determination of individual kidney function in the treatment of chronic renal obstruction.

    PubMed

    Belis, J A; Belis, T E; Lai, J C; Goodwin, C A; Gabriele, O F

    1982-04-01

    Differential radionuclide renal scans can be useful in the management of patients with chronic partial obstruction of 1 kidney. The 99mtechnetium diethylenetriaminepentaacetic acid perfusion scan can be used to assess glomerular blood flow. The 131iodine orthoiodohippurate renal scan provides qualitative functional information from scintigrams and quantitative evaluation of effective renal plasma flow to each kidney, as well as a total excretory index. Sequential 99mtechnetium diethylenetriaminepentaacetic acid and 131iodine orthoiodohippurate renal scans were used to assess individual renal function before and after surgical correction of unilateral chronic renal obstruction in 31 patients. The preservation of cortical perfusion on 99mtechnetium diethylenetriaminepentaacetic acid scans indicated that potential existed for partial recovery of renal function. Effective renal plasma flow and excretory index determined in conjunction with the 131iodine orthoiodohippurate scans provided a quantitative assessment of preoperative renal function, an evaluation of the effect of surgery and a sensitive method for long-term evaluation of differential renal function. Correction of ureteropelvic junction obstruction usually resulted in improvement in unilateral renal function. Neither nephrolithotomy nor extended pyelolithotomy diminished renal function in the kidney subjected to an operation and often improved it. Patients with long-standing distal ureteral obstruction had the least improvement in renal function postoperatively.

  20. Radionuclide determination of individual kidney function in the treatment of chronic renal obstruction

    SciTech Connect

    Belis, J.A.; Belis, T.E.; Lai, J.C.; Goodwin, C.A.; Gabriele, O.F.

    1982-04-01

    Differential radionuclide renal scans can be useful in the management of patients with chronic partial obstruction of 1 kidney. The /sup 99m/Tc diethylenetriaminepentaacetic acid perfusion scan can be used to assess glomerular blood flow. The /sup 131/I orthoiodohippurate renal scan provides qualitative functional information from scintigrams and quantitative evaluation of effective renal plasma flow to each kidney, as well as a total excretory index. Sequential /sup 99m/Tc diethylenetriaminepentaacetic acid and /sup 131/I orthoiodohippurate renal scans were used to assess individual renal function before and after surgical correction of unilateral chronic renal obstruction in 31 patients. The preservation of cortical perfusion on /supb 99m/Tc diethylenetriaminepentaacetic acid scans indicated that potential existed for partial recovery of renal function. Effective renal plasma flow and excretory index determined in conjunction with the /sup 131/I orthoiodohippurate scans provided a quantitative assessment of preoperative renal function, an evaluation of the effect of surgery and a sensitive method for long-term evaluation of differential renal function. Correction of ureteropelvic junction obstruction usually resulted in improvement in unilateral renal function. Neither nephrolithotomy nor extended pyelolithotomy diminished renal function in the kidney subjected to an operation and often improved it. Patients with long-standing distal ureteral obstruction had the least improvement in renal function postoperatively.

  1. Effects of laser acupuncture on blood perfusion rate

    NASA Astrophysics Data System (ADS)

    Wang, Xian-ju; Zeng, Chang-chun; Liu, Han-ping; Liu, Song-hao; Liu, Liang-gang

    2006-09-01

    Based on Pennes equation, the influences of the intensity and the impulse frequency of laser acupuncture on the point tissues' blood flow perfusion rate are discussed. We find that the blood perfusion rate of point tissue increases with the intensity of laser acupuncture increasing. After impulse laser acupuncture the point tissue blood perfusion rate increase little, but after continuum laser acupuncture the point tissues blood perfusion rate increase much.

  2. Perfusion MRI: The Five Most Frequently Asked Clinical Questions

    PubMed Central

    Essig, Marco; Nguyen, Thanh Binh; Shiroishi, Mark S.; Saake, Marc; Provenzale, James M.; Enterline, David S.; Anzalone, Nicoletta; Dörfler, Arnd; Rovira, Àlex; Wintermark, Max; Law, Meng

    2013-01-01

    OBJECTIVE This article addresses questions that radiologists frequently ask when planning, performing, processing, and interpreting MRI perfusion studies in CNS imaging. CONCLUSION Perfusion MRI is a promising tool in assessing stroke, brain tumors, and neurodegenerative diseases. Most of the impediments that have limited the use of perfusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols. PMID:23971482

  3. Role of hypothermic machine perfusion in liver transplantation.

    PubMed

    Schlegel, Andrea; Dutkowski, Philipp

    2015-06-01

    Machine liver perfusion has significantly evolved during the last ten years to optimize extended criteria liver grafts and to address the worldwide organ shortage. This review gives an overview on available ex vivo and in vivo data on hypothermic machine liver perfusion. We discuss also possible protective pathways and show most recent clinical applications of hypothermic machine liver perfusion in human.

  4. National Low-Level Waste Management Program Radionuclide Report Series

    SciTech Connect

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This volume serves as an introduction to the National Low-Level Radioactive Waste Management Program Radionuclide Report Series. This report includes discussions of radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha-emitting transuranics with half-lives greater than five years). Each report includes information regarding radiological and chemical characteristics of specific radionuclides. Information is also included discussing waste streams and waste forms that may contain each radionuclide, and radionuclide behavior in the environment and in the human body. Not all radionuclides commonly found at low-level radioactive waste sites are included in this report. The discussion in this volume explains the rationale of the radionuclide selection process.

  5. Uptake by plants of radionuclides from FUSRAP waste materials

    SciTech Connect

    Knight, M.J.

    1983-04-01

    Radionuclides from FUSRAP wastes potentially may be taken up by plants during remedial action activities and permanent near-surface burial of contaminated materials. In order to better understand the propensity of radionuclides to accumulate in plant tissue, soil and plant factors influencing the uptake and accumulation of radionuclides by plants are reviewed. In addition, data describing the uptake of the principal radionuclides present in FUSRAP wastes (uranium-238, thorium-230, radium-226, lead-210, and polonium-210) are summarized. All five radionuclides can accumulate in plant root tissue to some extent, and there is potential for the translocation and accumulation of these radionuclides in plant shoot tissue. Of these five radionuclides, radium-226 appears to have the greatest potential for translocation and accumulation in plant shoot tissue. 28 references, 1 figure, 3 tables.

  6. Panic attack triggering myocardial ischemia documented by myocardial perfusion imaging study. A case report

    PubMed Central

    2012-01-01

    Background Chest pain, a key element in the investigation of coronary artery disease is often regarded as a benign prognosis when present in panic attacks. However, panic disorder has been suggested as an independent risk factor for long-term prognosis of cardiovascular diseases and a trigger of acute myocardial infarction. Objective Faced with the extreme importance in differentiate from ischemic to non-ischemic chest pain, we report a case of panic attack induced by inhalation of 35% carbon dioxide triggering myocardial ischemia, documented by myocardial perfusion imaging study. Discussion Panic attack is undoubtedly a strong component of mental stress. Patients with coronary artery disease may present myocardial ischemia in mental stress response by two ways: an increase in coronary vasomotor tone or a sympathetic hyperactivity leading to a rise in myocardial oxygen consumption. Coronary artery spasm was presumed to be present in cases of cardiac ischemia linked to panic disorder. Possibly the carbon dioxide challenge test could trigger myocardial ischemia by the same mechanisms. Conclusion The use of mental stress has been suggested as an alternative method for myocardial ischemia investigation. Based on translational medicine objectives the use of CO2 challenge followed by Sestamibi SPECT could be a useful method to allow improved application of research-based knowledge to the medical field, specifically at the interface of PD and cardiovascular disease. PMID:22999016

  7. Tricarboxylic acid cycle metabolites during ischemia in isolated perfused rat heart.

    PubMed

    Peuhkurinen, K J; Takala, T E; Nuutinen, E M; Hassinen, I E

    1983-02-01

    Isolated rat hearts were, after a retrograde perfusion by the Langendorff procedure, rendered ischemic by lowering the aortic pressure to zero. The rate of proteolysis and temporal patterns of the changes in the concentrations of the metabolites of the tricarboxylic acid cycle, related amino acids, ammonia, and breakdown products of the adenine nucleotides were determined. The most significant change in the amino acid metabolism was a decrease of the proteolysis to one-tenth and a large accumulation of alanine, which was almost stoichiometric to the degradation of aspartate plus asparagine. The accumulation of malate and succinate was small compared with the metabolic net fluxes of aspartate and alanine. The metabolic balance sheet suggests that aspartate was converted to alanine. A prerequisite for this would be a feed in of carbon of aspartate to the tricarboxylic acid cycle as oxalacetate, reversal of the malate dehydrogenase, and production of pyruvate by the malic enzyme reaction. Alanine accumulating during ischemia is not glycolytic in origin but occurs through a concerted operation of anaplerotic reactions and tricarboxylic acid cycle metabolite disposal. The data also suggest that the potentially energy-yielding reduction of fumarate to succinate is not significant in the ischemic myocardium.

  8. Circular tomosynthesis for neuro perfusion imaging on an interventional C-arm

    NASA Astrophysics Data System (ADS)

    Claus, Bernhard E.; Langan, David A.; Al Assad, Omar; Wang, Xin

    2015-03-01

    There is a clinical need to improve cerebral perfusion assessment during the treatment of ischemic stroke in the interventional suite. The clinician is able to determine whether the arterial blockage was successfully opened but is unable to sufficiently assess blood flow through the parenchyma. C-arm spin acquisitions can image the cerebral blood volume (CBV) but are challenged to capture the temporal dynamics of the iodinated contrast bolus, which is required to derive, e.g., cerebral blood flow (CBF) and mean transit time (MTT). Here we propose to utilize a circular tomosynthesis acquisition on the C-arm to achieve the necessary temporal sampling of the volume at the cost of incomplete data. We address the incomplete data problem by using tools from compressed sensing and incorporate temporal interpolation to improve our temporal resolution. A CT neuro perfusion data set is utilized for generating a dynamic (4D) volumetric model from which simulated tomo projections are generated. The 4D model is also used as a ground truth reference for performance evaluation. The performance that may be achieved with the tomo acquisition and 4D reconstruction (under simulation conditions, i.e., without considering data fidelity limitations due to imaging physics and imaging chain) is evaluated. In the considered scenario, good agreement between the ground truth and the tomo reconstruction in the parenchyma was achieved.

  9. Performance comparison between static and dynamic cardiac CT on perfusion quantitation and patient classification tasks

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Cardiac CT acquisitions for perfusion assessment can be performed in a dynamic or static mode. In this simulation study, we evaluate the relative classification and quantification performance of these modes for assessing myocardial blood flow (MBF). In the dynamic method, a series of low dose cardiac CT acquisitions yields data on contrast bolus dynamics over time; these data are fit with a model to give a quantitative MBF estimate. In the static method, a single CT acquisition is obtained, and the relative CT numbers in the myocardium are used to infer perfusion states. The static method does not directly yield a quantitative estimate of MBF, but these estimates can be roughly approximated by introducing assumed linear relationships between CT number and MBF, consistent with the ways such images are typically visually interpreted. Data obtained by either method may be used for a variety of clinical tasks, including 1) stratifying patients into differing categories of ischemia and 2) using the quantitative MBF estimate directly to evaluate ischemic disease severity. Through simulations, we evaluate the performance on each of these tasks. The dynamic method has very low bias in MBF estimates, making it particularly suitable for quantitative estimation. At matched radiation dose levels, ROC analysis demonstrated that the static method, with its high bias but generally lower variance, has superior performance in stratifying patients, especially for larger patients.

  10. Lung Perfusion Scanning in Hepatic Cirrhosis

    PubMed Central

    Stanley, N. N.; Ackrill, P.; Wood, J.

    1972-01-01

    Abnormal lung perfusion scans using radioactive particles were found in five out of six cases of hepatic cirrhosis with arterial hypoxaemia. None had clinical evidence of cardiopulmonary disease or signs of pulmonary embolism on arteriography. The scan defects are probably caused by a disorder of the pulmonary microvasculature, which may show regional variation in severity. ImagesFIG. 1FIG. 2 PMID:4645896

  11. Coupling between resting cerebral perfusion and EEG.

    PubMed

    O'Gorman, R L; Poil, S-S; Brandeis, D; Klaver, P; Bollmann, S; Ghisleni, C; Lüchinger, R; Martin, E; Shankaranarayanan, A; Alsop, D C; Michels, L

    2013-07-01

    While several studies have investigated interactions between the electroencephalography (EEG) and functional magnetic resonance imaging BOLD signal fluctuations, less is known about the associations between EEG oscillations and baseline brain haemodynamics, and few studies have examined the link between EEG power outside the alpha band and baseline perfusion. Here we compare whole-brain arterial spin labelling perfusion MRI and EEG in a group of healthy adults (n = 16, ten females, median age: 27 years, range 21-48) during an eyes closed rest condition. Correlations emerged between perfusion and global average EEG power in low (delta: 2-4 Hz and theta: 4-7 Hz), middle (alpha: 8-13 Hz), and high (beta: 13-30 Hz and gamma: 30-45 Hz) frequency bands in both cortical and sub-cortical regions. The correlations were predominately positive in middle and high-frequency bands, and negative in delta. In addition, central alpha frequency positively correlated with perfusion in a network of brain regions associated with the modulation of attention and preparedness for external input, and central theta frequency correlated negatively with a widespread network of cortical regions. These results indicate that the coupling between average EEG power/frequency and local cerebral blood flow varies in a frequency specific manner. Our results are consistent with longstanding concepts that decreasing EEG frequencies which in general map onto decreasing levels of activation.

  12. Nuclear cardiology: Myocardial perfusion and function

    SciTech Connect

    Seldin, D.W. )

    1991-08-01

    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.

  13. A reappraisal of retrograde cerebral perfusion

    PubMed Central

    2013-01-01

    Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients. PMID:23977600

  14. Asynchronicity of facial blood perfusion in migraine.

    PubMed

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  15. Asynchronicity of Facial Blood Perfusion in Migraine

    PubMed Central

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A.; Kamshilin, Alexei A.; Närhi, Matti; Karjalainen, Pasi A.; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology. PMID:24324592

  16. Myocardial metabolism, perfusion, wall motion and electrical activity in Duchenne muscular dystrophy

    SciTech Connect

    Perloff, J.K.; Henze, E.; Schelbert, H.R.

    1982-01-01

    The cardiomyopathy of Duchenne's muscular dystrophy originates in the posterobasal left ventricle and extends chiefly to the contiguous lateral wall. Ultrastructural abnormalities in these regions precede connective tissue replacement. We postulated that a metabolic fault coincided with or antedated the subcellular abnormality. Accordingly, regional left ventricular metabolism, perfusion and wall motion were studied using positron computed tomography and metabolic isotopes supplemented by thallium perfusion scans, equilibrium radionuclide angiography and M-mode and two-dimensional echocardiography. To complete the assessment, electrocardiograms, vectorcardiograms, 24 hour taped electrocardiograms and chest x-rays were analyzed. Positron computed tomography utilizing F-18 2-fluoro 2-deoxyglucose (FDG) provided the first conclusive evidence supporting the hypothesis of a premorphologic regional metabolic fault. Thus, cardiac involvement in duchenne dystrophy emerges as a unique form of heart disease, genetically targeting specific regions of ventricular myocardium for initial metabolic and subcellular changes. Reported ultrastructural abnormalities of the impulse and conduction systems provide, at least in part, a basis for the clinically observed sinus node, intraatrial, internodal, AV nodal and infranodal disorders.

  17. Effect of combined VEGF165/ SDF-1 gene therapy on vascular remodeling and blood perfusion in cerebral ischemia.

    PubMed

    Hu, Guo-Jie; Feng, Yu-Gong; Lu, Wen-Peng; Li, Huan-Ting; Xie, Hong-Wei; Li, Shi-Fang

    2016-12-16

    OBJECTIVE Therapeutic neovascularization is a promising strategy for treating patients after an ischemic stroke; however, single-factor therapy has limitations. Stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) proteins synergistically promote angiogenesis. In this study, the authors assessed the effect of combined gene therapy with VEGF165 and SDF-1 in a rat model of cerebral infarction. METHODS An adenoviral vector expressing VEGF165 and SDF-1 connected via an internal ribosome entry site was constructed (Ad- VEGF165-SDF-1). A rat model of middle cerebral artery occlusion (MCAO) was established; either Ad- VEGF165-SDF-1 or control adenovirus Ad- LacZ was stereotactically microinjected into the lateral ventricle of 80 rats 24 hours after MCAO. Coexpression and distribution of VEGF165 and SDF-1 were examined by reverse-transcription polymerase chain reaction, Western blotting, and immunofluorescence. The neurological severity score of each rat was measured on Days 3, 7, 14, 21, and 28 after MCAO. Angiogenesis and vascular remodeling were evaluated via bromodeoxyuridine and CD34 immunofluorescence labeling. Relative cerebral infarction volumes were determined by T2-weighted MRI and triphenyltetrazolium chloride staining. Cerebral blood flow, relative cerebral blood volume, and relative mean transmit time were assessed using perfusion-weighted MRI. RESULTS The Ad- VEGF165-SDF-1 vector mediated coexpression of VEGF165 and SDF-1 in multiple sites around the ischemic core, including the cortex, corpus striatum, and hippocampal granular layer. Coexpression of VEGF165 and SDF-1 improved neural function, reduced cerebral infarction volume, increased microvascular density and promoted angiogenesis in the ischemic penumbra, and improved cerebral blood flow and perfusion. CONCLUSIONS Combined VEGF165 and SDF-1 gene therapy represents a potential strategy for improving vascular remodeling and recovery of neural function after cerebral

  18. NIR fluorescent image-based evaluation of gastric tube perfusion after esophagectomy in preclinical model (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kim, Minji; Quan, Yuhua; Han, Kook Nam; Choi, Byeong Hyun; Choi, Yeonho; Kim, Hyun Koo; Kim, Beop-Min

    2016-03-01

    This study was to evaluate the feasibility of near infrared (NIR) fluorescent images as a tool for evaluating the perfusion of the gastric tube after esophagectomy. In addition, we investigated the time required to acquire enough signal to confirm the presence of ischemia in gastric tube after injection of indocyanine green (ICG) through peripheral versus and central venous route. 4 porcine underwent esophagogastrostomy and their right gastric arteries were ligated to mimic ischemic condition of gastric tube. ICG (0.6mg/kg) was intravenously injected and the fluorescence signal-to-background ratios (SBR) were measured by using the custom-built intraoperative color and fluorescence imaging system (ICFIS). We evaluated perfusion of gastric tubes by comparing their SBR with esophageal SBR. In ischemic models, SBR of esophagus was higher than that of gastric tube (2.8+/-0.54 vs. 1.7+/-0.37, p<0.05). It showed high esophagus-stomach signal to signal ratio. (SSR, 1.8+/-0.76). We also could observe recovery of blood perfusion in few minutes after releasing the ligation of right gastric artery. In addition, in comparison study according to the injection route of ICG, The time to acquire signal stabilization was faster in central than in peripheral route (119 +/- 65.1 seconds in central route vs. 295+/-130.4 in peripheral route, p<0.05). NIR fluorescent images could provide the real-time information if there was ischemia or not in gastric tube during operation. And, central injection of ICG might give that information faster than peripheral route.

  19. Study of retinal vessel oxygen saturation in ischemic and non-ischemic branch retinal vein occlusion

    PubMed Central

    Lin, Lei-Lei; Dong, Yan-Min; Zong, Yao; Zheng, Qi-Shan; Fu, Yue; Yuan, Yong-Guang; Huang, Xia; Qian, Garrett; Gao, Qian-Ying

    2016-01-01

    AIM To explore how oxygen saturation in retinal blood vessels is altered in ischemic and non-ischemic branch retinal vein occlusion (BRVO). METHODS Fifty BRVO eyes were divided into ischemic (n=26) and non-ischemic (n=24) groups, based on fundus fluorescein angiography. Healthy individuals (n=52 and n=48, respectively) were also recruited as controls for the two groups. The mean oxygen saturations of the occluded vessels and central vessels were measured by oximetry in the BRVO and control groups. RESULTS In the ischemic BRVO group, the occluded arterioles oxygen saturation (SaO2-A, 106.0%±14.3%), instead of the occluded venule oxygen saturation (SaO2-V, 60.8%±9.4%), showed increases when compared with those in the same quadrant vessels (SaO2-A, 86.1%±16.5%) in the contralateral eyes (P<0.05). The oxygen saturations of the central vessels showed similar trends with those of the occluded vessels. In the non-ischemic BRVO group, the occluded and central SaO2-V and SaO2-A showed no significant changes. In both the ischemic and non-ischemic BRVOs, the central SaO2-A was significantly increased when compared to healthy individuals. CONCLUSION Obvious changes in the occluded and central SaO2-A were found in the ischemic BRVO group, indicating that disorders of oxygen metabolism in the arterioles may participate in the pathogenesis of ischemic BRVO. PMID:26949618

  20. Tachycardic vs. pharmacologic stress myocardial perfusion imaging: differential implications in multi-vessel ischemia

    PubMed Central

    Nguyen, Thanh H; Horowitz, John D; Unger, Steven A

    2012-01-01

    Background In patients unable to exercise, potential methods of induction of reversible myocardial ischemia include physiological heart rate acceleration via pacing or dobutamine infusion and asymmetric coronary vasodilatation using dipyridamole. Although their bases for induction of ischemia are widely disparate, no direct comparison of these techniques has previously been reported. Methods We performed a randomised, paired comparison of dipyridamole and pacing myocardial perfusion imaging (MPI) in 28 patients in whom exercise stress imaging was precluded, comparing the detection, localisation and quantitation of ischemia. Results Reversible myocardial ischemia was detected in 21 patients, concordantly in 13 (p = 0.042). There was a high degree of concordance (p < 0.0001) regarding locations of sites of ischemia. While there was a good correlation (r = 0.74, p < 0.0001) between size of total ischemic zones with dipyridamole and pacing, the magnitude of ischemia tended to be greater with dipyridamole (mean percentage of left ventricular myocardium ± SD, 9.4 ± 11.0% vs. 7.0 ± 9.0%, p = 0.091). Furthermore, this difference resulted from accentuation of the primary ischemic zone with dipyridamole in patients with multi-vessel ischemia (mean ± SD, 28.1 ± 21.1% vs. 18.7 ± 16.1%, p = 0.046). Conclusions Despite major differences in mechanism(s) of induction of ischemia, dipyridamole and pacing produce similar results regarding detection, localisation and severity of ischemia. However, dipyridamole accentuates ischemia in primary (vs. secondary) ischemic zones, consistent with known induction of coronary “steal". This should be taken into account in interpretation of scan results. PMID:22254212

  1. Robust Low-dose CT Perfusion Deconvolution via Tensor Total-Variation Regularization

    PubMed Central

    Zhang, Shaoting; Chen, Tsuhan; Sanelli, Pina C.

    2016-01-01

    Acute brain diseases such as acute strokes and transit ischemic attacks are the leading causes of mortality and morbidity worldwide, responsible for 9% of total death every year. ‘Time is brain’ is a widely accepted concept in acute cerebrovascular disease treatment. Efficient and accurate computational framework for hemodynamic parameters estimation can save critical time for thrombolytic therapy. Meanwhile the high level of accumulated radiation dosage due to continuous image acquisition in CT perfusion (CTP) raised concerns on patient safety and public health. However, low-radiation leads to increased noise and artifacts which require more sophisticated and time-consuming algorithms for robust estimation. In this paper, we focus on developing a robust and efficient framework to accurately estimate the perfusion parameters at low radiation dosage. Specifically, we present a tensor total-variation (TTV) technique which fuses the spatial correlation of the vascular structure and the temporal continuation of the blood signal flow. An efficient algorithm is proposed to find the solution with fast convergence and reduced computational complexity. Extensive evaluations are carried out in terms of sensitivity to noise levels, estimation accuracy, contrast preservation, and performed on digital perfusion phantom estimation, as well as in-vivo clinical subjects. Our framework reduces the necessary radiation dose to only 8% of the original level and outperforms the state-of-art algorithms with peak signal-to-noise ratio improved by 32%. It reduces the oscillation in the residue functions, corrects over-estimation of cerebral blood flow (CBF) and under-estimation of mean transit time (MTT), and maintains the distinction between the deficit and normal regions. PMID:25706579

  2. Longitudinal MR imaging study in the prediction of ischemic susceptibility after cerebral hypoperfusion in rats: Influence of aging and hypertension.

    PubMed

    Lee, J-T; Liu, H-L; Yang, J-T; Yang, S-T; Lin, J-R; Lee, T-H

    2014-01-17

    Our previous study has shown that aging and hypertension may alter apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) and increase ischemic susceptibility in the non-ischemic rat brain. The present study wishes to further investigate whether aging and hypertension may influence cerebral diffusion/perfusion and increase ischemic susceptibility in the ischemic brain. Brain magnetic resonance (MR) imaging was examined 1day before and 1 and 7days after bilateral common carotid artery occlusion. Young and middle-aged normotensive Wistar-Kyoto rats and young and middle-aged spontaneously hypertensive rats (SHRs) were studied. Infarction occurred mainly in the parietal cortex and was larger in middle-aged SHRs than the other three groups (P<0.05). In pre-operation, ADC was higher and CBF was lower in middle-aged/hypertensive rats than young/normotensive rats (P<0.05). The ADC was higher in the parietal cortex of the rats with infarction at 7days when compared to the rats without infarction [receiver operating characteristic curve (ROC), P=0.001; binary logistic regression (BLR), P=0.006]. However, there was no difference in the hippocampus and thalamus. At day 1 post-operation, CBF reduced and ADC/CBF ratio elevated significantly in the parietal cortex of the rats with infarction when compared to the rats without infarction (CBF: ROC, P=0.002; BLR, P=0.017. ADC/CBF ratio: ROC, P=0.001; BLR, P=0.018). Our results demonstrated that pre-operation ADC and post-operation CBF and ADC/CBF ratio can be used as good MR markers in the prediction of ischemic susceptibility after cerebral hypoperfusion.

  3. Simultaneous assessment of left ventricular wall motion and myocardial perfusion with technetium-99m-methoxy isobutyl isonitrile at stress and rest in patients with angina: Comparison with thallium-201 SPECT

    SciTech Connect

    Villanueva-Meyer, J.; Mena, I.; Narahara, K.A. )

    1990-04-01

    The newly developed technetium-99m ({sup 99m}Tc) isonitriles can be used for the simultaneous evaluation of ventricular function and myocardial perfusion. We compared technetium-99m hexakis-2-methoxy isobutyl isonitrile (({sup 99m}Tc) MIBI) derived first-pass left ventricular wall motion at stress and rest with simultaneous myocardial perfusion defined by ({sup 99m}Tc)MIBI SPECT. These results were then compared with {sup 201}TI SPECT. We examined 28 patients with coronary artery disease; 25 had a previous myocardial infarction. We found concordance between segmental wall motion and myocardial perfusion imaging in defining normal, ischemic, and infarcted myocardium in 68% and 69% of segments using ({sup 99m}Tc)MIBI and {sup 201}TI respectively. The best agreement between wall motion and myocardial perfusion was seen in the inferior wall, while most of the discrepancies were found at the apex. Agreement between ({sup 99m}Tc)MIBI and {sup 201}TI SPECT myocardial perfusion was seen in 93% of segments. Technetium-99m-MIBI appears to be an ideal radiopharmaceutical for the simultaneous evaluation of ventricular function and myocardial perfusion during stress and at rest.

  4. Improving cancer treatment with cyclotron produced radionuclides

    SciTech Connect

    Larson, S.M. Finn, R.D.

    1992-08-04

    This report describes the author's continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program has 3 interactive components: Radiochemistry /Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section under the DOE grant during the 1989--1992 grant period, will be employed in the Pharmacology and Immunology sections of the DOE grant during the 1992--1995 grant period. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  5. Decline of radionuclides in Columbia River biota

    SciTech Connect

    Cushing, C.E.; Watson, D.G.; Scott, A.J.; Gurtisen, J.M.

    1980-03-01

    In January 1971, the last of nine plutonium production reactors using direct discharge of once-through cooling waters into the Columbia River was closed. Sampling was initiated at three stations on the Columbia River to document the decline of the radionuclide body burdens in the biota of the Columbia River ecosystem. The data show that in a river-reservoir complex, the measurable body burden of fission-produced radionuclides decreased to essentially undetectable levels within 18 to 24 mo after cessation of discharge of once-through cooling water into the river. On the basis of data from the free-flowing station, we believe that this decrease would be even more rapid in an unimpounded river.

  6. Methods and systems for detection of radionuclides

    DOEpatents

    Coates, Jr., John T.; DeVol, Timothy A.

    2010-05-25

    Disclosed are materials and systems useful in determining the existence of radionuclides in an aqueous sample. The materials provide the dual function of both extraction and scintillation to the systems. The systems can be both portable and simple to use, and as such can beneficially be utilized to determine presence and optionally concentration of radionuclide contamination in an aqueous sample at any desired location and according to a relatively simple process without the necessity of complicated sample handling techniques. The disclosed systems include a one-step process, providing simultaneous extraction and detection capability, and a two-step process, providing a first extraction step that can be carried out in a remote field location, followed by a second detection step that can be carried out in a different location.

  7. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggrregated albumin (/sup 99m/Tc MAA) labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cutaneous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  8. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary vasculature resulting in intrapulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggregated albumin labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cuntaeous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  9. Cadastral valuation of lands polluted with radionuclides

    NASA Astrophysics Data System (ADS)

    Makarov, O. A.; Tsvetnov, E. V.; Shcheglov, A. I.; Romashkina, A. D.; Ermiyaev, Ya. R.

    2016-11-01

    The major method to correct the cadastral value of land for contamination with radionuclides is to reduce it by the sum of expenses necessary for land remediation and for special measures ensuring the obtaining of agricultural and forestry products satisfying safety norms. Lands contaminated with radionuclides and used in agriculture and forestry are often removed from the system of land taxation. In this case, their cadastral value becomes an excessive element of the state cadaster of real estate. An approach toward cadastral valuation of such lands suggested by the authors assumes the creation of a system of compensation payments as the main source of financing of land rehabilitation and soil conservation measures. An original system of calculation of such payments has been tested for radioactively contaminated lands in Plavsk district of Tula oblast. It is argued that compensation payments for radioactively contaminated agrocenoses should be higher than those for natural cenoses.

  10. Radionuclide synovectomy – essentials for rheumatologists

    PubMed Central

    Felis-Giemza, Anna; Kobylecka, Małgorzata

    2016-01-01

    Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70–80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice. PMID:27504020

  11. Perfusion-weighted imaging and dynamic 4D angiograms for the estimation of collateral blood flow in lacunar infarction.

    PubMed

    Förster, Alex; Mürle, Bettina; Böhme, Johannes; Al-Zghloul, Mansour; Kerl, Hans U; Wenz, Holger; Groden, Christoph

    2016-10-01

    Although lacunar infarction accounts for approximately 25% of ischemic strokes, collateral blood flow through anastomoses is not well evaluated in lacunar infarction. In 111 lacunar infarction patients, we analyzed diffusion-weighted images, perfusion-weighted images, and blood flow on dynamic four-dimensional angiograms generated by use of Signal Processing In NMR-Software. Blood flow was classified as absent (type 1), from periphery to center (type 2), from center to periphery (type 3), and combination of type 2 and 3 (type 4). On diffusion-weighted images, lacunar infarction was found in the basal ganglia (11.7%), internal capsule (24.3%), corona radiata (30.6%), thalamus (24.3%), and brainstem (9.0%). In 58 (52.2%) patients, perfusion-weighted image showed a circumscribed hypoperfusion, in one (0.9%) a circumscribed hyperperfusion, whereas the remainder was normal. In 36 (62.1%) patients, a larger perfusion deficit (>7 mm) was observed. In these, blood flow was classified type 1 in four (11.1%), 2 in 17 (47.2%), 3 in 9 (25.0%), and 4 in six (16.7%) patients. Patients with lacunar infarction in the posterior circulation more often demonstrated blood flow type 2 and less often type 3 (p = 0.01). Detailed examination and graduation of blood flow in lacunar infarction by use of dynamic four-dimensional angiograms is feasible and may serve for a better characterization of this stroke subtype.

  12. Radionuclide transfer from feed to camel milk.

    PubMed

    Al-Masri, M S; Al-Hamwi, A; Amin, Y; Safieh, M B; Zarkawi, M; Soukouti, A; Dayyoub, R; Voigt, G; Fesenko, S

    2014-06-01

    The transfer of (137)Cs, (85)Sr, (131)I, (210)Po, (210)Pb and (238)U from feed to camel's milk was investigated in a pilot experiment with three lactating camels. For a period of 60 days, the animals were fed on spiked feed containing the studied radionuclides. They were subsequently returned to a contamination-free diet and monitored for another 90 days. The activity concentrations of (137)Cs, (85)Sr and (131)I in milk decreased with time and reached background levels after 20 days. Equilibrium transfer coefficients and biological half-lives were estimated and transfer coefficients were calculated as (8.1 ± 3.6) × 10(-4), (4.4 ± 1.6) × 10(-2), (7.8 ± 3.9) × 10(-4), (2.7 ± 3.5) × 10(-4), (1.8 ± 1.5) × 10(-4) and (7.0 ± 3.6) × 10(-3) d L(-1) for (85)Sr, (131)I, (137)Cs, (210)Po, (210)Pb and (238)U, respectively. The biological half-lives were estimated to be 6.4, 4.2, 8.9, and 53.3 days for (85)Sr, (131)I, (137)Cs, and (238)U, respectively. Estimates of the half-lives were based on a one component model: it was found that the half-life values measured for artificial radionuclides were slightly shorter than those for natural radionuclides. The data obtained in the study are the first published experimental data on radionuclide transfer to camel milk.

  13. Breast-Dedicated Radionuclide Imaging Systems.

    PubMed

    Hsu, David F C; Freese, David L; Levin, Craig S

    2016-02-01

    Breast-dedicated radionuclide imaging systems show promise for increasing clinical sensitivity for breast cancer while minimizing patient dose and cost. We present several breast-dedicated coincidence-photon and single-photon camera designs that have been described in the literature and examine their intrinsic performance, clinical relevance, and impact. Recent tracer development is mentioned, results from recent clinical tests are summarized, and potential areas for improvement are highlighted.

  14. Radionuclide Air Emission Report for 2009

    SciTech Connect

    Wahl, Linnea

    2010-06-01

    Berkeley Lab operates facilities where radionuclides are handled and stored. These facilities are subject to the EPA radioactive air emission regulations in 40CFR61, Subpart H (EPA 1989). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2009, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]). These minor sources included more than 100 stack sources and one source of diffuse emissions. There were no unplanned emissions from the Berkeley Lab site. Emissions from minor sources (stacks and diffuse emissions) either were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building-specific and common parameters, Laboratory personnel applied the EPA-approved computer code, CAP88-PC, to calculate the effective dose equivalent to the maximally exposed individual (MEI). The effective dose equivalent from all sources at Berkeley Lab in 2009 is 7.0 x 10{sup -3} mrem/yr (7.0 x 10{sup -5} mSv/yr) to the MEI, well below the 10 mrem/yr (0.1 mSv/yr) dose standard. The location of the MEI is at the University of California (UC) Lawrence Hall of Science, a public science museum about 1500 ft (460 m) east of Berkeley Lab's Building 56. The estimated collective effective dose equivalent to persons living within 50 mi (80 km) of Berkeley Lab is 1.5 x 10{sup -1} person-rem (1.5 x 10{sup -3} person-Sv) attributable to the Lab's airborne emissions in 2009.

  15. Radionuclide Air Emission Report for 2007

    SciTech Connect

    Wahl, Linnea; Wahl, Linnea

    2008-06-13

    Berkeley Lab operates facilities where radionuclides are handled and stored. These facilities are subject to the U.S. Environmental Protection Agency (EPA) radioactive air emission regulations in Code of Federal Regulations (CFR) Title 40, Part 61, Subpart H (EPA 1989). The EPA regulates radionuclide emissions that may be released from stacks or vents on buildings where radionuclide production or use is authorized or that may be emitted as diffuse sources. In 2007, all Berkeley Lab sources were minor stack or building emissions sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]), there were no diffuse emissions, and there were no unplanned emissions. Emissions from minor sources either were measured by sampling or monitoring or were calculated based on quantities received for use or produced during the year. Using measured and calculated emissions, and building-specific and common parameters, Laboratory personnel applied the EPA-approved computer code, CAP88-PC, Version 3.0, to calculate the effective dose equivalent to the maximally exposed individual (MEI). The effective dose equivalent from all sources at Berkeley Lab in 2007 is 1.2 x 10{sup -2} mrem/yr (1.2 x 10{sup -4} mSv/yr) to the MEI, well below the 10 mrem/yr (0.1 mSv/yr) EPA dose standard. The location of the MEI is at the University of California (UC) Lawrence Hall of Science, a public science museum about 1500 ft (460 m) east of Berkeley Lab's Building 56. The estimated collective effective dose equivalent to persons living within 50 mi (80 km) of Berkeley Lab is 3.1 x 10{sup -1} person-rem (3.1 x 10{sup -3} person-Sv) attributable to the Lab's airborne emissions in 2007.

  16. Radionuclide bone scintigraphy in pediatric orthopedics

    SciTech Connect

    Conway, J.J.

    1986-12-01

    Radionuclide bone scintigraphy is highly sensitive and specific for diagnosing the musculoskeletal disorders of childhood. Conditions such as neonatal osteomyelitis, septic arthritis, diskitis of childhood, Legg-Calve-Perthes disease, the osteochondroses, the toddler's fracture, sports injuries, spondylolysis, myositis ossificians, and reflex sympathetic dystrophy are readily defined. High-quality state-of-the-art scintigraphy is essential in infants and young children. 64 references.

  17. Radionuclide Air Emission Report for 2008

    SciTech Connect

    Wahl, Linnea

    2009-05-21

    Berkeley Lab operates facilities where radionuclides are handled and stored. These facilities are subject to the U.S. Environmental Protection Agency (EPA) radioactive air emission regulations in Code of Federal Regulations (CFR) Title 40, Part 61, Subpart H (EPA 1989). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2008, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]). These minor sources include more than 100 stack sources and one source of diffuse emissions. There were no unplanned emissions from the Berkeley Lab site. Emissions from minor sources (stacks and diffuse emissions) either were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building-specific and common parameters, Laboratory personnel applied the EPA-approved computer code, CAP88-PC, to calculate the effective dose equivalent to the maximally exposed individual (MEI). The effective dose equivalent from all sources at Berkeley Lab in 2008 is 5.2 x 10{sup -3} mrem/yr (5.2 x 10{sup -5} mSv/yr) to the MEI, well below the 10 mrem/yr (0.1 mSv/yr) dose standard. The location of the MEI is at the University of California (UC) Lawrence Hall of Science, a public science museum about 1500 ft (460 m) east of Berkeley Lab's Building 56. The estimated collective effective dose equivalent to persons living within 50 mi (80 km) of Berkeley Lab is 1.1 x 10{sup -1} person-rem (1.1 x 10{sup -3} person-Sv) attributable to the Lab's airborne emissions in 2008.

  18. Concrete Property and Radionuclide Migration Tests

    SciTech Connect

    Wellman, Dawn M.; Mattigod, Shas V.; Powers, Laura; Parker, Kent E.; Clayton, Libby N.; Wood, Marcus I.

    2008-10-01

    The Waste Management Project provides safe, compliant, and cost-effective waste management services for the Hanford Site and the DOE Complex. Part of theses services includes safe disposal of LLW and MLLW at the Hanford Low-Level Waste Burial Grounds (LLBG) in accordance with the requirements listed in DOE Order 435.1, Radioactive Waste Management. To partially satisfy these requirements, a Performance Assessment (PA) analyses were completed and approved. DOE Order 435.1 also requires that continuing data collection be conducted to enhance confidence in the critical assumptions used in these analyses to characterize the operational features of the disposal facility that are relied upon to satisfy the performance objectives identified in the Order. One critical assumption is that concrete will frequently be used as waste form or container material to control and minimize the release of radionuclide constituents in waste into the surrounding environment. Data was collected to (1) quantify radionuclide migration through concrete materials similar to those used to encapsulate waste in the LLBG, (2) measure the properties of the concrete materials, especially those likely to influence radionuclide migration, and (3) quantify the stability of U-bearing solid phases of limited solubility in concrete.

  19. UPTAKE OF RADIONUCLIDE METALS BY SPME FIBERS

    SciTech Connect

    Duff, M; S Crump, S; Robert02 Ray, R; Keisha Martin, K; Donna Beals, D

    2006-08-28

    The Federal Bureau of Investigation (FBI) Laboratory currently does not have on site facilities for handling radioactive evidentiary materials and there are no established FBI methods or procedures for decontaminating high explosive (HE) and fire debris (FD) evidence while maintaining evidentiary value. One experimental method for the isolation of HE and FD residue involves using solid phase microextraction or SPME fibers to remove residue of interest. Due to their high affinity for organics, SPME fibers should have little affinity for most metals. However, no studies have measured the affinity of radionuclides for SPME fibers. The focus of this research was to examine the affinity of dissolved radionuclide ({sup 239/240}Pu, {sup 238}U, {sup 237}Np, {sup 85}Sr, {sup 133}Ba, {sup 137}Cs, {sup 60}Co and {sup 226}Ra) and stable radionuclide surrogate metals (Sr, Co, Ir, Re, Ni, Ba, Cs, Nb, Zr, Ru, and Nd) for SPME fibers at the exposure conditions that favor the uptake of HE and FD residues. Our results from radiochemical and mass spectrometric analyses indicate these metals have little measurable affinity for these SPME fibers during conditions that are conducive to HE and FD residue uptake with subsequent analysis by liquid or gas phase chromatography with mass spectrometric detection.

  20. [Biosorption of Radionuclide Uranium by Deinococcus radiodurans].

    PubMed

    Yang, Jie; Dong, Fa-qin; Dai, Qun-wei; Liu, Ming-xue; Nie, Xiao-qin; Zhang, Dong; Ma, Jia-lin; Zhou, Xian

    2015-04-01

    As a biological adsorbent, Living Deinococcus radiodurans was used for removing radionuclide uranium in the aqueous solution. The effect factors on biosorption of radionuclide uranium were researched in the present paper, including solution pH values and initial uranium concentration. Meanwhile, the biosorption mechanism was researched by the method of FTIR and SEM/EDS. The results show that the optimum conditions for biosorption are as follows: pH = 5, co = 100 mg · L(-1) and the maximum biosorption capacity is up to 240 mgU · g(-1). According to the SEM results and EDXS analysis, it is indicated that the cell surface is attached by lots of sheet uranium crystals, and the main biosorpiton way of uranium is the ion exchange or surface complexation. Comparing FTIR spectra and FTIR fitting spectra before and after biosorption, we can find that the whole spectra has a certain change, particularly active groups (such as amide groups of the protein, hydroxy, carboxyl and phosphate group) are involved in the biosorption process. Then, there is a new peak at 906 cm(-1) and it is a stretching vibration peak of UO2(2+). Obviously, it is possible that as an anti radiation microorganism, Deinococcus radiodurans could be used for removing radionuclide uranium in radiation environment.

  1. TU-EF-204-02: Hiigh Quality and Sub-MSv Cerebral CT Perfusion Imaging

    SciTech Connect

    Li, Ke; Niu, Kai; Wu, Yijing; Chen, Guang-Hong

    2015-06-15

    Purpose: CT Perfusion (CTP) imaging is of great importance in acute ischemic stroke management due to its potential to detect hypoperfused yet salvageable tissue and distinguish it from definitely unsalvageable tissue. However, current CTP imaging suffers from poor image quality and high radiation dose (up to 5 mSv). The purpose of this work was to demonstrate that technical innovations such as Prior Image Constrained Compressed Sensing (PICCS) have the potential to address these challenges and achieve high quality and sub-mSv CTP imaging. Methods: (1) A spatial-temporal 4D cascaded system model was developed to indentify the bottlenecks in the current CTP technology; (2) A task-based framework was developed to optimize the CTP system parameters; (3) Guided by (1) and (2), PICCS was customized for the reconstruction of CTP source images. Digital anthropomorphic perfusion phantoms, animal studies, and preliminary human subject studies were used to validate and evaluate the potentials of using these innovations to advance the CTP technology. Results: The 4D cascaded model was validated in both phantom and canine stroke models. Based upon this cascaded model, it has been discovered that, as long as the spatial resolution and noise properties of the 4D source CT images are given, the 3D MTF and NPS of the final CTP maps can be analytically derived for a given set of processing methods and parameters. The cascaded model analysis also identified that the most critical technical factor in CTP is how to acquire and reconstruct high quality source images; it has very little to do with the denoising techniques often used after parametric perfusion calculations. This explained why PICCS resulted in a five-fold dose reduction or substantial improvement in image quality. Conclusion: Technical innovations generated promising results towards achieving high quality and sub-mSv CTP imaging for reliable and safe assessment of acute ischemic strokes. K. Li, K. Niu, Y. Wu: Nothing to

  2. Genetic Predisposition to Ischemic Stroke

    PubMed Central

    Kamatani, Yoichiro; Takahashi, Atsushi; Hata, Jun; Furukawa, Ryohei; Shiwa, Yuh; Yamaji, Taiki; Hara, Megumi; Tanno, Kozo; Ohmomo, Hideki; Ono, Kanako; Takashima, Naoyuki; Matsuda, Koichi; Wakai, Kenji; Sawada, Norie; Iwasaki, Motoki; Yamagishi, Kazumasa; Ago, Tetsuro; Ninomiya, Toshiharu; Fukushima, Akimune; Hozawa, Atsushi; Minegishi, Naoko; Satoh, Mamoru; Endo, Ryujin; Sasaki, Makoto; Sakata, Kiyomi; Kobayashi, Seiichiro; Ogasawara, Kuniaki; Nakamura, Motoyuki; Hitomi, Jiro; Kita, Yoshikuni; Tanaka, Keitaro; Iso, Hiroyasu; Kitazono, Takanari; Kubo, Michiaki; Tanaka, Hideo; Tsugane, Shoichiro; Kiyohara, Yutaka; Yamamoto, Masayuki; Sobue, Kenji; Shimizu, Atsushi

    2017-01-01

    Background and Purpose— The prediction of genetic predispositions to ischemic stroke (IS) may allow the identification of individuals at elevated risk and thereby prevent IS in clinical practice. Previously developed weighted multilocus genetic risk scores showed limited predictive ability for IS. Here, we investigated the predictive ability of a newer method, polygenic risk score (polyGRS), based on the idea that a few strong signals, as well as several weaker signals, can be collectively informative to determine IS risk. Methods— We genotyped 13 214 Japanese individuals with IS and 26 470 controls (derivation samples) and generated both multilocus genetic risk scores and polyGRS, using the same derivation data set. The predictive abilities of each scoring system were then assessed using 2 independent sets of Japanese samples (KyushuU and JPJM data sets). Results— In both validation data sets, polyGRS was shown to be significantly associated with IS, but weighted multilocus genetic risk scores was not. Comparing the highest with the lowest polyGRS quintile, the odds ratios for IS were 1.75 (95% confidence interval, 1.33–2.31) and 1.99 (95% confidence interval, 1.19–3.33) in the KyushuU and JPJM samples, respectively. Using the KyushuU samples, the addition of polyGRS to a nongenetic risk model resulted in a significant improvement of the predictive ability (net reclassification improvement=0.151; P<0.001). Conclusions— The polyGRS was shown to be superior to weighted multilocus genetic risk scores as an IS prediction model. Thus, together with the nongenetic risk factors, polyGRS will provide valuable information for individual risk assessment and management of modifiable risk factors. PMID:28034966

  3. Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters

    SciTech Connect

    ,

    1981-04-01

    The study objective of "The Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters" is to synthesize and test radionuclide transport models capable of realistically assessing radionuclide transport in various types of surface water bodies by including the sediment-radionuclide interactions. These interactions include radionuclide adsorption by sediment; desorption from sediment into water; and transport, deposition, and resuspension of sorbed radionuclides controlled by the sediment movements. During FY-1979, the modification of sediment and contaminant (radionuclide) transport model, FETRA, was completed to make it applicable to coastal waters. The model is an unsteady, two-dimensional (longitudinal and lateral) model that consists of three submodels (for sediment, dissolved-contaminant, and particulate-contaminant transport), coupled to include the sediment-contaminant interactions. In estuaries, flow phenomena and consequent sediment and radionuclide migration are often three-dimensional in nature mainly because of nonuniform channel cross-sections, salinity intrusion, and lateral-flow circulation. Thus, an unsteady, three-dimensional radionuclide transport model for estuaries is also being synthesized by combining and modifying a PNL unsteady hydrothermal model and FETRA. These two radionuclide transport models for coastal waters and estuaries will be applied to actual sites to examine the validity of the codes.

  4. Selective cerebral perfusion for cerebral protection: what we do know

    PubMed Central

    Tang, Gilbert H. L.

    2013-01-01

    Selective antegrade cerebral perfusion (SACP) for aortic arch surgery has evolved considerably since it was first reported. Various pressure rates have been investigated through animal models, as has the effect of warmer perfusate temperatures and hematocrit. Clinical research into pH management, the role of unilateral and bilateral perfusion, and core temperatures have further refined the procedure. We recommend the following protocol for SACP: perfusion pressure between 40-60 mmHg, flow rates between 6-10 mL/kg/min, and perfusate temperature of 20-28 °C; core cooling to 18-30 °C contingent on duration of arrest; alpha-stat pH management; hematocrit between 25-30%; near infrared spectroscopy to monitor cerebral perfusion; and bilateral perfusion when prolonged durations of SACP is anticipated. PMID:23977601

  5. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    SciTech Connect

    Dowdle, S.C.; Human, D.G.; Mann, M.D. )

    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.

  6. Resilience in Patients with Ischemic Heart Disease

    PubMed Central

    de Lemos, Conceição Maria Martins; Moraes, David William; Pellanda, Lucia Campos

    2016-01-01

    Background Resilience is a psychosocial factor associated with clinical outcomes in chronic diseases. The relationship between this protective factor and certain diseases, such heart diseases, is still under-explored. Objective The present study sought to investigate the frequency of resilience in individuals with ischemic heart disease. Method This was a cross-sectional study with 133 patients of both genders, aged between 35 and 65 years, treated at Rio Grande do Sul Cardiology Institute - Cardiology University Foundation, with a diagnosis of ischemic heart disease during the study period. Sixty-seven patients had a history of acute myocardial infarction. The individuals were interviewed and evaluated by the Wagnild & Young resilience scale and a sociodemographic questionnaire. Results Eighty-one percent of patients were classified as resilient according to the scale. Conclusion In the sample studied, resilience was identified in high proportion among patients with ischemic heart disease. PMID:26815312

  7. Mitral valve repair for ischemic mitral regurgitation.

    PubMed

    Mohebali, Jahan; Chen, Frederick Y

    2015-05-01

    Mitral valve repair for ischemic mitral valve regurgitation remains controversial. In moderate mitral regurgitation (MR), controversy exists whether revascularization alone will be adequate to restore native valve geometry or whether intervention on the valve (repair) should be performed concomitantly. When MR is severe, the need for valve intervention is not disputed. Rather, the controversy is whether repair versus replacement should be undertaken. In contrast to degenerative or myxomatous disease that directly affects leaflet integrity and morphology, ischemic FMR results from a distortion and dilation of native ventricular geometry that normally supports normal leaflet coaptation. To address this, the first and most crucial step in successful valve repair is placement of an undersized, complete remodeling annuloplasty ring to restore the annulus to its native geometry. The following article outlines the steps for repair of ischemic mitral regurgitation.

  8. Spectroscopic monitoring of kidney tissue ischemic injury

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Jason T.; Michalopoulou, Andromachi P.; Troppmann, Christoph; Demos, Stavros G.

    2004-07-01

    Noninvasive evaluation of tissue viability of donor kidneys used for transplantation is an issue that current technology is not able to address. In this work, we explore optical spectroscopy for its potential to assess the degree of ischemic damage in kidney tissue. We hypothesized that ischemic damage to kidney tissue will give rise to changes in its optical properties which in turn may be used to asses the degree of tissue injury. The experimental results demonstrate that the autofluorescence intensity of the injured kidney is decreasing as a function of time exposed to ischemic injury. Changes were also observed in the NIR light scattering intensities most probably arising from changes due to injury and death of the tissue.

  9. Spectroscopic Monitoring of Kidney Tissue Ischemic Injury

    SciTech Connect

    Demos, S G; Fitzgerald, J T; Michalopoulou, A P; Troppmann, C

    2004-03-11

    Noninvasive evaluation of tissue viability of donor kidneys used for transplantation is an issue that current technology is not able to address. In this work, we explore optical spectroscopy for its potential to assess the degree of ischemic damage in kidney tissue. We hypothesized that ischemic damage to kidney tissue will give rise to changes in its optical properties which in turn may be used to asses the degree of tissue injury. The experimental results demonstrate that the autofluorescence intensity of the injured kidney is decreasing as a function of time exposed to ischemic injury. Changes were also observed in the NIR light scattering intensities most probably arising from changes due to injury and death of the tissue.

  10. The Groningen hypothermic liver perfusion pump: functional evaluation of a new machine perfusion system.

    PubMed

    van der Plaats, A; Maathuis, M H J; 'T Hart, N A; Bellekom, A A; Hofker, H S; van der Houwen, E B; Verkerke, G J; Leuvenink, H G D; Verdonck, P; Ploeg, R J; Rakhorst, G

    2006-12-01

    To improve preservation of donor livers, we have developed a portable hypothermic machine perfusion (HMP) system as an alternative for static cold storage. A prototype of the system was built and evaluated on functionality. Evaluation criteria included 24 h of adequate pressure controlled perfusion, sufficient oxygenation, a maintained 0-4 degrees C temperature and sterile conditions. Porcine livers were perfused with pump pressures that were set at 4 mmHg (continuous, portal vein) and 30/20 mmHg, at 60 BPM (pulsatile, hepatic artery). Control livers were preserved using the clinical golden standard: static cold storage. In the HMP group, pressure, flow and temperature were continuously monitored for 24 h. At time-points t = 0, 2, 4, 8, 12, and 24 h samples of University of Wisconsin machine preservation solution were taken for measurement of partial oxygen pressure (pO(2)) and lacto-dehydrogenase. Biopsies in every lobe were taken for histology and electron microscopy; samples of ice, preservation solution, liver surface, and bile were taken and cultured to determine sterility. Results showed that temperature was maintained at 0-4 degrees C; perfusion pressure was maintained at 4 mmHg and 30/20 mmHg for portal vein and hepatic artery, respectively. Flow was approximately 350 and 80 ml/min, respectively, but decreased in the portal vein, probably due to edema formation. Arterial pO(2) was kept at 100 kPa. Histology showed complete perfusion of the liver with no major damage to hepatocytes, bile ducts, and non-parenchymal cells compared to control livers. The machine perfusion system complied to the design criteria and will have to demonstrate the superiority of machine perfusion over cold storage in transplant experiments.

  11. A new characterization for nonarteritic anterior ischemic optic neuropathy

    PubMed Central

    Li, Aipeng; Li, Lin; Li, Miyang; Shi, Xiaoru

    2015-01-01

    This study is to investigate the clinical characteristics of patients with nonarteritic anterior ischemic optic neuropathy (NAION). Totally 133 patients (156 eyes) were included in this study. At the first visit and follow-up visits, the patients were subjected to the ophthalmic evaluations, including the fundus photography, visual field (VF) test, fluorescein fundus angiography, and optical coherence tomography (OCT). The visual acuity (VA) of 156 eyes and the VF of 148 eyes were evaluated. For the VA assessment, 59 (38%), 67 (43%), and 30 (19%) cases presented with an initial VA ≥ 20/40, between 20/40 and 20/400, and ≤ 20/400, respectively. VA was improved in 44% and deteriorated in 8% of the patients with VA < 20/20 after NAION onset. Inferior or superior altitudinal defects, constricted fields, and nasal steps were the most common VF defects. In the eyes with VF defects, 32 cases (22%) were improved, and 25 cases (17%) were worsened. In the 61 cases (39%) with VA ≤ 20/200 at NAION onset, neuroepithelial detachment in the fovea was found in 37 eyes (61%). For the optic disc assessment, retinal nerve fiber layer (RNFL) thickening was the most common symptom of NAION. Out of the 36 eyes with ONA or DR, 72% showed VA improvement after the NAION occurrence in the contralateral eye. Poor microcirculation perfusion in the bilateral optic nerve hypoplasia (ONH) might be the underlying mechanism for NAION, which could be relieved by compromising the blood supply to the one side. PMID:26770482

  12. Ischemic Gastropathic Ulcer Mimics Gastric Cancer

    PubMed Central

    Daher, Saleh; Lahav, Ziv; Rmeileh, Ayman Abu; Mizrahi, Meir

    2016-01-01

    Gastric ulcer due to mesenteric ischemia is a rare clinical finding. As a result, few reports of ischemic gastric ulcers have been reported in the literature. The diagnosis of ischemic gastropathy is seldom considered in patients presenting with abdominal pain and gastric ulcers. In this case report, we describe a patient with increasing abdominal pain, weight loss, and gastric ulcers, who underwent extensive medical evaluation and whose symptoms were resistant to medical interventions. Finally he was diagnosed with chronic mesenteric ischemia, and his clinical and endoscopic abnormalities resolved after surgical revascularization of both the superior mesenteric artery and the celiac trunk. PMID:27579191

  13. Ischemic Gastropathic Ulcer Mimics Gastric Cancer.

    PubMed

    Daher, Saleh; Lahav, Ziv; Rmeileh, Ayman Abu; Mizrahi, Meir; Khoury, Tawfik

    2016-01-01

    Gastric ulcer due to mesenteric ischemia is a rare clinical finding. As a result, few reports of ischemic gastric ulcers have been reported in the literature. The diagnosis of ischemic gastropathy is seldom considered in patients presenting with abdominal pain and gastric ulcers. In this case report, we describe a patient with increasing abdominal pain, weight loss, and gastric ulcers, who underwent extensive medical evaluation and whose symptoms were resistant to medical interventions. Finally he was diagnosed with chronic mesenteric ischemia, and his clinical and endoscopic abnormalities resolved after surgical revascularization of both the superior mesenteric artery and the celiac trunk.

  14. Endovascular ischemic stroke models of adult rhesus monkeys: a comparison of two endovascular methods

    PubMed Central

    Wu, Di; Chen, Jian; Wang, Bincheng; Zhang, Mo; Shi, Jingfei; Ma, Yanhui; Zhu, Zixin; Yan, Feng; He, Xiaoduo; Li, Shengli; Dornbos III, David; Ding, Yuchuan; Ji, Xunming

    2016-01-01

    To further investigate and improve upon current stroke models in nonhuman primates, infarct size, neurologic function and survival were evaluated in two endovascular ischemic models in sixteen rhesus monkeys. The first method utilized a micro-catheter or an inflatable balloon to occlude the M1 segment in six monkeys. In the second model, an autologous clot was injected via a micro-catheter into the M1 segment in ten monkeys. MRI scanning was performed on all monkeys both at baseline and 3 hours after the onset of ischemia. Spetzler neurologic functions were assessed post-operatively, and selective perfusion deficits were confirmed by DSA and MRI in all monkeys. Animals undergoing micro-catheter or balloon occlusion demonstrated more profound hemiparesis, larger infarct sizes, lower Spetzler neurologic scores and increased mortality compared to the thrombus occlusion group. In animals injected with the clot, there was no evidence of dissolution, and the thrombus was either near the injection site (M1) or flushed into the superior division of the MCA (M2). All animals survived the M2 occlusion. M1 occlusion with thrombus generated 50% mortality. This study highlighted clinically important differences in these two models, providing a platform for further study of a translational thromboembolic model of acute ischemic stroke. PMID:27534985

  15. Ischemic post-conditioning to counteract intestinal ischemia/reperfusion injury

    PubMed Central

    Guan, Yan-Fang; Pritts, Timothy A; Montrose, Marshall H

    2010-01-01

    Intestinal ischemia is a severe disorder with a variety of causes. Reperfusion is a common occurrence during treatment of acute intestinal ischemia but the injury resulting from ischemia/reperfusion (IR) may lead to even more serious complications from intestinal atrophy to multiple organ failure and death. The susceptibility of the intestine to IR-induced injury (IRI) appears from various experimental studies and clinical settings such as cardiac and major vascular surgery and organ transplantation. Whereas oxygen free radicals, activation of leukocytes, failure of microvascular perfusion, cellular acidosis and disturbance of intracellular homeostasis have been implicated as important factors in the pathogenesis of intestinal IRI, the mechanisms underlying this disorder are not well known. To date, increasing attention is being paid in animal studies to potential pre- and post-ischemia treatments that protect against intestinal IRI such as drug interference with IR-induced apoptosis and inflammation processes and ischemic pre-conditioning. However, better insight is needed into the molecular and cellular events associated with reperfusion-induced damage to develop effective clinical protection protocols to combat this disorder. In this respect, the use of ischemic post-conditioning in combination with experimentally prolonged acidosis blocking deleterious reperfusion actions may turn out to have particular clinical relevance. PMID:21607154

  16. Bone marrow and bone marrow derived mononuclear stem cells therapy for the chronically ischemic myocardium

    SciTech Connect

    Waksman, Ron; Baffour, Richard

    2003-09-01

    Bone marrow stem cells have been shown to differentiate into various phenotypes including cardiomyocytes, vascular endothelial cells and smooth muscle. Bone marrow stem cells are mobilized and home in to areas of injured myocardium where they are involved in tissue repair. In addition, bone marrow secretes multiple growth factors, which are essential for angiogenesis and arteriogenesis. In some patients, these processes are not enough to avert clinical symptoms of ischemic disease. Therefore, in vivo administration of an adequate number of stem cells would be a significant therapeutic advance. Unfractionated bone marrow derived mononuclear stem cells, which contain both hematopoietic and nonhematopoietic cells may be more appropriate for cell therapy. Studies in animal models suggest that implantation of different types of stem cells improve angiogenesis and arteriogenesis, tissue perfusion as well as left ventricular function. Several unanswered questions remain. For example, the optimal delivery approach, dosage and timing of the administration of cell therapy as well as durability of improvements need to be studied. Early clinical studies have demonstrated safety and feasibility of various cell therapies in ischemic disease. Randomized, double blind and placebo-controlled clinical trials need to be completed to determine the effectiveness of stem cell.

  17. Liver free fatty acid (FFA) accumulation as an indicator of ischemic injury during cold preservation

    SciTech Connect

    Nemoto, E.M.; Kang, Y.; DeWolf, A.M.; Lin, M.R.; Bleyaert, A.L.; Winter, P.M.

    1987-05-01

    Reliable assessment of hepatic viability prior to harvest and transplant could improve graft success and aid in evaluating the efficacy of liver preservation techniques. Hepatic tissue metabolites, protein (Pr) synthesis, and ATP have been studied, but none reliably correlate with hepatic viability. Therefore, they studied changes in liver FFA relative to changes in ATP and Pr synthesis during cold ischemic preservation. Rats mechanically ventilated on 0.5% isoflurane/70% N/sub 2/O/30% O/sub 2/ were heparinized and their livers perfused with air-equilibrated Euro-Collins solution (ECS) at 0-4/sup 0/C and kept on ice. A piece of the liver was removed after 0, 2, 6, 8, 12, 24, 36 and 48 h of preservation for ATP and FFA analysis. A portion of the liver was sliced (250 ..mu..m thick) and incubated in vitro for /sup 14/C-lysine incorporation in albumin. ATP, FFA and Pr synthesis were unchanged in the first 8 h, but markedly decreased between 8 and 12 h with little change thereafter. In contrast, between 8 and 48 h, arachidonic and stearic acids increased by 5 and 2-fold, respectively. Changes in ATP and Pr synthesis correlate with the empirically derived clinical maximum of 8 to 12 h preservation. FFA accumulation appears to reflect hepatic ischemic injury and may be a means of evaluating the quality of a donor liver.

  18. Cerebral collateral therapeutics in acute ischemic stroke: A randomized preclinical trial of four modulation strategies.

    PubMed

    Beretta, Simone; Versace, Alessandro; Carone, Davide; Riva, Matteo; Dell'Era, Valentina; Cuccione, Elisa; Cai, Ruiyao; Monza, Laura; Pirovano, Silvia; Padovano, Giada; Stiro, Fabio; Presotto, Luca; Paternò, Giovanni; Rossi, Emanuela; Giussani, Carlo; Sganzerla, Erik P; Ferrarese, Carlo

    2017-01-01

    Cerebral collaterals are dynamically recruited after arterial occlusion and highly affect tissue outcome in acute ischemic stroke. We investigated the efficacy and safety of four pathophysiologically distinct strategies for acute modulation of collateral flow (collateral therapeutics) in the rat stroke model of transient middle cerebral artery (MCA) occlusion. A composed randomization design was used to assign rats (n = 118) to receive phenylephrine (induced hypertension), polygeline (intravascular volume load), acetazolamide (cerebral arteriolar vasodilation), head down tilt (HDT) 15° (cerebral blood flow diversion), or no treatment, starting 30 min after MCA occlusion. Compared to untreated animals, treatment with collateral therapeutics was associated with lower infarct volumes (62% relative mean difference; 51.57 mm(3) absolute mean difference; p < 0.001) and higher chance of good functional outcome (OR 4.58, p < 0.001). Collateral therapeutics acutely increased cerebral perfusion in the medial (+40.8%; p < 0.001) and lateral (+19.2%; p = 0.016) MCA territory compared to pretreatment during MCA occlusion. Safety indicators were treatment-related mortality and cardiorespiratory effects. The highest efficacy and safety profile was observed for HDT. Our findings suggest that acute modulation of cerebral collaterals is feasible and provides a tissue-saving effect in the hyperacute phase of ischemic stroke prior to recanalization therapy.

  19. Ischemic penumbra in acute stroke: Demonstration by PET with fluorine-18 fluoromisonidazole

    SciTech Connect

    Yeh, S.H.; Liu, R.S.; Hu, H.H.

    1994-05-01

    Ischemic penumbra (IP) in acute stroke has gained clinical interest since tissue functions may be recovered if perfusion can be reestablished. However, such therapeutic intervention is {open_quotes}blind{close_quotes} since clinical examination can not distinguish IP from developing infarction. In vivo demonstration of IP may have significance for stroke patient management. This study was a preliminary evaluation of detecting IP in vivo by F-18 fluoromisonidazole ([F-18]-FMISO), a hypoxic imaging agent. Static PET imaging was performed after IV injection of 370 MBq of [F-18]-FMISO at 20 and 120 min. Tomograms were reconstructed and evaluated visually in correlation with CT or MR scans. In acute stroke, patients (pts) were called back for the second PET study one month after the initial study. CT was used for confirming infarction. In 6 pts with acute cerebral infarction, three of them had intense [F-18]-FMISO retention in the penumbra surrounding the central, eclipse-like zone of absent radio-activity (infarction) at 2 hr in the acute state, and the penumbra disappeared in association with increased area of infarction on CT in one case in the chronic state. In five pts with chronic infarction, all had no penumbra of [F-18]-FMISO retention. In summary, our preliminary results demonstrate the feasibility of using [F-18]-FMISO PET to detect ischemic penumbra in vivo.

  20. Imaging of drug effects in perfused liver

    NASA Astrophysics Data System (ADS)

    Dammann, Marc; Mahlke, Christine; Kessler, Manfred D.

    2002-06-01

    Various medications affect the systemic circulation and organ oxygenation causing dilatation or constriction of blood vessels. Imminent liver failure can be generated by reduced perfusion of different origins. In this case hepatic vasodilatation would be a therapeutical approach for improving patient's condition. Our examinations have been performed in perfused rat liver using spectrometric methods. Two defined areas of the liver were measured punctually. We compared the influence of Tetramethylpyrazine and Glyceroltrinitrate on hemoglobin oxygenation (HbO2) and concentration (Hb-conc.) in rat liver after application of Norepinephrine, which caused a mid decrease in hemoglobin oxygenation of 47,9 %. Both increased the HbO2, but differed from each other in manner of time and extent. Tetramethylpyrazine indicated a longer effect than Glyceroltrinitrate. Furthermore, HbO2 and Hb-conc. showed a conversed relation. From the shape of the absorption spectra it is possible to derive the oxygenation of hemoglobin.

  1. Effect of cardiac dysrhythmia on cerebral perfusion.

    PubMed

    Sand, B J; Rose, H B; Barker, W F

    1976-07-01

    Extracranial carotid arterial obstructive disease has been the entity most commonly associated with transient cerebrovascular insufficiency. A nonobstructive, frequently overlooked cause of cerebral ischemia is cardiac dysrhythmia. We have explored this by observations of experimental animals and of man. Blood flow and pressure in the carotid arteries of dogs were shown to be decreased by mechnically induced premature ventricular contractions. The significance of the cardiogenic contribution to altered cerebrovascular perfusion was studied by ocular and brachial plethysmography in 210 patients suspected by history of having carotid arterial insufficiency. Of the 210 patients, 62 demonstrated abnormal ocular plethysmographic recordings, and of those, nine had dysrhythmias associated with significant deficits of ocular perfusion. Five patients whose recordings were technically suitable for publication are presented to demonstrate the bizarre ocular plethysmographic recordings seen during the dysrhythmic cycle.

  2. Restoration of myocardial bioenergetic metabolism in swine after periods of ischemic ventricular fibrillation.

    PubMed

    Skinner, F P; Levitzky, M G; Scott, R F; Fricks, J

    1975-05-01

    Myocardial mitochondrial function and high energy phosphate levels were measured in normal swine, in swine after either 5 or 10 minutes of ischemic ventricular fibrillation (IVF) while on cardiopulmonary bypass, and in swine defibrillated after either 5 or 10 minutes of IVE. The damage to myocardial mitochondria induced by IVF, such as partial uncoupling, decreased oxygen uptake, and loss of cytochrome oxidase activity, was completely reversed almost instantly by coronary artery perfusion and the restoration of sinus rhythm. After either 5 or 10 minutes of IVF followed by coronary artery reperfusion and defibrillation, myocardial creatine phosphate (CP), adenosine monophosphate (AMP) and adenosine diphosphate (ADP) return to normal levels very rapidly. However, adenosine triphosphate (ATP) levels remain significantly lower than control levels. If the bioenergetic mechanisms of swine and human myocardium are similar, it appears that IVF at least for a 10 minute period produces no damage to myocardial mitochondria that is not corrected by perfusion of the coronary arteries and re-establishment of sinus rhythm. Furthermore, sinus rhythm can be re-established and maintained despite signficantly lower levels of myocardial ATP.

  3. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    PubMed Central

    Koenitzer, Jeffrey R.; Bonacci, Gustavo; Woodcock, Steven R.; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E.; Schopfer, Francisco J.

    2015-01-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H+ and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  4. Bed-side assessment of cerebral perfusion in stroke patients based on optical monitoring of a dye bolus by time-resolved diffuse reflectance.

    PubMed

    Liebert, A; Wabnitz, H; Steinbrink, J; Möller, M; Macdonald, R; Rinneberg, H; Villringer, A; Obrig, H

    2005-01-15

    We present a minimally invasive optical method, that is, multi-channel time-domain diffuse near-infrared reflectometry of the head to assess cerebral blood perfusion that is applicable at the bed-side and repetitively at short intervals. Following intravenous injection of an ICG bolus, its transit through intra- and extracerebral tissue is monitored based on changes in moments of distributions of times of flight of photons, recorded with a 4-channel instrument simultaneously on both hemispheres. In healthy volunteers, we found that variance of distributions of times of flight of photons is well suited to assess latency and initial slope of the increase in absorption of intracerebral tissue due to the bolus. We successfully applied our method in two patients demonstrating a reversible cerebral perfusion deficit in an ischemic stroke patient who was treated by thrombolysis and in another patient with a permanent impaired unilateral perfusion due to ipsilateral internal carotid artery occlusion. In either case, we observed a difference in bolus transit time between the hemispheres. In the stroke patient, this difference resolved when re-evaluated 1 day after thrombolysis. The study demonstrates the necessity of a technique with sub-nanosecond time resolution to allow for depth discrimination if clinical perfusion monitoring of cerebrovascular diseases is addressed by optical methods.

  5. Imaging acute ischemic tissue acidosis with pH-sensitive endogenous amide proton transfer (APT) MRI - Correction of tissue relaxation and concomitant RF irradiation effects toward mapping quantitative cerebral tissue pH

    PubMed Central

    Sun, Phillip Zhe; Wang, Enfeng; Cheung, Jerry S

    2011-01-01

    Amide proton transfer (APT) MRI is sensitive to ischemic tissue acidosis and has been increasingly used as a research tool to investigate disrupted tissue metabolism during acute stroke. However, magnetization transfer asymmetry (MTRasym) analysis is often used for calculating APT contrast, which only provides pH-weighted images. In addition to pH- dependent APT contrast, in vivo MTRasym is subject to a baseline shift (ΔMTR′asym) attributable to the slightly asymmetric magnetization transfer (MT) effect. Additionally, APT contrast approximately scales with T1 relaxation time. Tissue relaxation time may also affect the experimentally obtainable APT contrast via saturation efficiency and RF spillover effects. In this study, we acquired perfusion, diffusion, relaxation and pH-weighted APT MRI data, and spectroscopy (MRS) in an animal model of acute ischemic stroke. We modeled in vivo MTRasym as a superposition of pH-dependent APT contrast and a baseline shift ΔMTR′asym (i.e., MTRasym=APTR(pH) + ΔMTR′asym), and quantified tissue pH. We found pH of the contralateral normal tissue to be 7.03 ± 0.05 and the ipsilateral ischemic tissue pH was 6.44 ± 0.24, which correlated with tissue perfusion and diffusion rates. In summary, our study established an endogenous and quantitative pH imaging technique for improved characterization of ischemic tissue acidification and metabolism disruption. PMID:22178815

  6. The effects of cilostazol on tissue oxygenation upon an ischemic-reperfusion injury in the mouse cerebrum.

    PubMed

    Morikawa, Takayuki; Hattori, Katsuji; Kajimura, Mayumi; Suematsu, Makoto

    2010-01-01

    Although cilostazol, an inhibitor of cyclic nucleotide phosphodiesterase 3 (PDE3), is known to exert a potent antiplatelet function by raising intracellular cAMP concentration, its effect on cerebral microcirculation upon an ischemic insult is not clearly understood. To examine effects of cilostazol on the global ischemic injury in the brain, we first measured the plasma leakage using modified Miles assay after mice had been subjected to 60 min of a bilateral common carotid artery (BCCA) occlusion followed by reperfusion for 4 h. Oral treatment with cilostazol (30 mg/kg) significantly increased plasma leakage. This result led us to examine if the treatment with cilostazol recruits more capillaries leading to an increase in surface area for exchange and oxygen transport to tissues. To do so, we simultaneously measured degrees of tissue hypoxia and vessel perfusion. Pimonidazol was injected intraperitoneally 1 h before sacrifice and capillary patency was assessed by fluorescein isothiocyanate-labeled Lycopersicon esculentum lectin bound to the endothelial surface. Treatment with cilostazol markedly increased the capillary patency which was accompanied by a reduction in the hypoxic area. Although the treatment with cilostazol caused an increase in the flux of plasma proteins across endothelial barrier that may imply an adverse role after a BCCA occlusion, this increase in protein leakage was attributable to the increased surface area for exchange which in turn brought about a reduction in tissue hypoxia. Taken together cilostazol appears to produce a protective effect against the ischemic-reperfusion injury.

  7. Multiparametric Magnetic Resonance Imaging for Prediction of Parenchymal Hemorrhage in Acute Ischemic Stroke After Reperfusion Therapy

    PubMed Central

    R. Knitter, James; Jahan, Reza; Gornbein, Jeffery; Ajani, Zahra; Feng, Lei; Meyer, Brett C.; Schwamm, Lee H.; Yoo, Albert J.; Marshall, Randolph S.; Meyers, Philip M.; Yavagal, Dileep R.; Wintermark, Max; Liebeskind, David S.; Guzy, Judy; Starkman, Sidney; Saver, Jeffrey L.; Kidwell, Chelsea S.

    2017-01-01

    Background and Purpose— Patients with acute ischemic stroke are at increased risk of developing parenchymal hemorrhage (PH), particularly in the setting of reperfusion therapies. We have developed a predictive model to examine the risk of PH using combined magnetic resonance perfusion and diffusion parameters, including cerebral blood volume (CBV), apparent diffusion coefficient, and microvascular permeability (K2). Methods— Voxel-based values of CBV, K2, and apparent diffusion coefficient from the ischemic core were obtained using pretreatment magnetic resonance imaging data from patients enrolled in the MR RESCUE clinical trial (Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy). The associations between PH and extreme values of imaging parameters were assessed in univariate and multivariate analyses. Receiver-operating characteristic curve analysis was performed to determine the optimal parameter(s) and threshold for predicting PH. Results— In 83 patients included in this analysis, 20 developed PH. Univariate analysis showed significantly lower 10th percentile CBV and 10th percentile apparent diffusion coefficient values and significantly higher 90th percentile K2 values within the infarction core of patients with PH. Using classification tree analysis, the 10th percentile CBV at threshold of 0.47 and 90th percentile K2 at threshold of 0.28 resulted in overall predictive accuracy of 88.7%, sensitivity of 90.0%, and specificity of 87.3%, which was superior to any individual or combination of other classifiers. Conclusions— Our results suggest that combined 10th percentile CBV and 90th percentile K2 is an independent predictor of PH in patients with acute ischemic stroke with diagnostic accuracy superior to individual classifiers alone. This approach may allow risk stratification for patients undergoing reperfusion therapies. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT00389467. PMID

  8. Cardiomyocyte mitochondria as targets of humoral factors released by remote ischemic preconditioning

    PubMed Central

    Gedik, Nilguen; Maciel, Leonardo; Schulte, Christiane; Skyschally, Andreas; Heusch, Gerd

    2016-01-01

    Introduction Remote ischemic preconditioning (RIPC) reduces myocardial infarct size, and protection can be transferred with plasma to other individuals, even across species. Mitochondria are the end-effectors of cardioprotection by local ischemic conditioning maneuvers. We have now analyzed mitochondrial function in response to RIPC. Material and methods Plasma from pigs undergoing placebo or RIPC (infarct size reduction by 67% in RIPC pigs compared to placebo) was transferred to isolated perfused rat hearts subjected to 30 min global ischemia followed by 120 min reperfusion for infarct size measurement. Additional experiments were terminated at 10 min reperfusion to isolate mitochondria for functional measurements. Effects of RIPC pig plasma were compared to local ischemic preconditioning (IPC) or to infusion of tumor necrosis factor α (TNF-α). Results Ischemia/reperfusion (I/R) induced an infarct of 41 ±2% of total ventricular mass. Placebo pig plasma did not affect infarct size (38 ±1, p = 0.13). The RIPC pig plasma reduced infarct size (27 ±2, p < 0.001), as did IPC (20 ±1, p < 0.001) and TNF-α (28 ±2, p < 0.001). Associated with cardioprotection, reductions of mitochondrial adenosine diphosphate (ADP)-stimulated respiration, adenosine triphosphate (ATP) production and calcium retention capacity (CRC) by I/R and placebo pig plasma were prevented by RIPC pig plasma, as they were by IPC and TNF-α. Mitochondrial reactive oxygen species production (nmol H2O2/100 µg protein) induced by I/R (272 ±34) was comparable in response to placebo pig plasma (234 ±28, p = 0.37) and was reduced by RIPC pig plasma (83 ±15, p < 0.001) as well as by IPC (78 ±21, p < 0.001) and TNF-α (125 ±42, p = 0.002). Conclusions In rat myocardium, mitochondria are an intracellular target of protection induced by humoral factors retrieved from pigs undergoing RIPC. PMID:28261301

  9. Conduction Remodeling in Human End-Stage Non-Ischemic Left Ventricular Cardiomyopathy

    PubMed Central

    Glukhov, Alexey V.; Fedorov, Vadim V.; Kalish, Paul W.; Ravikumar, Vinod K.; Lou, Qing; Janks, Deborah; Schuessler, Richard B.; Moazami, Nader; Efimov, Igor R.

    2012-01-01

    Background Several arrhythmogenic mechanisms have been inferred from animal heart failure (HF) models. However, the translation of these hypotheses is difficult due to lack of functional human data. We aimed to investigate the electrophysiological substrate for arrhythmia in human end-stage non-ischemic cardiomyopathy. Methods and Results We optically mapped the coronary-perfused left ventricular wedge preparations from human hearts with end-stage non-ischemic cardiomyopathy (HF, n=10) and non-failing hearts (NF, n=10). Molecular remodeling was studied with immunostaining, Western blotting, and histological analyses. HF produced heterogeneous prolongation of action potential duration (APD) resulting in the decrease of transmural APD dispersion (64±12 ms vs 129±15 ms in NF, P<0.005). In the failing hearts, transmural activation was significantly slowed from the endocardium (39±3 cm/s versus 49±2 cm/s in NF, P=0.008) to the epicardium (28±3 cm/s versus 40±2 cm/s in NF, P=0.008). Conduction slowing was likely due to Cx43 downregulation, decreased colocalization of Cx43 with N-cadherin (40±2% versus 52±5% in NF, P=0.02), and an altered distribution of phosphorylated Cx43 isoforms by the upregulation of the dephosphorylated Cx43 in both the subendocardium and subepicardium layers. Failing hearts further demonstrated spatially discordant conduction velocity alternans which resulted in nonuniform propagation discontinuities and wavebreaks conditioned by strands of increased interstitial fibrosis (fibrous tissue content in HF 16.4±7.7 versus 9.9±1.4% in NF, P=0.02). Conclusions Conduction disorder resulting from the anisotropic downregulation of Cx43 expression, the reduction of Cx43 phosphorylation, and increased fibrosis is likely to be a critical component of arrhythmogenic substrate in patients with non-ischemic cardiomyopathy. PMID:22412072

  10. Noncontact blood perfusion mapping in clinical applications

    NASA Astrophysics Data System (ADS)

    Iakovlev, Dmitry; Dwyer, Vincent; Hu, Sijung; Silberschmidt, Vadim

    2016-04-01

    Non-contact imaging photoplethysmography (iPPG) to detect pulsatile blood microcirculation in tissue has been selected as a successor to low spatial resolution and slow scanning blood perfusion techniques currently employed by clinicians. The proposed iPPG system employs a novel illumination source constructed of multiple high power LEDs with narrow spectral emission, which are temporally modulated and synchronised with a high performance sCMOS sensor. To ensure spectrum stability and prevent thermal wavelength drift due to junction temperature variations, each LED features a custom-designed thermal management system to effectively dissipate generated heat and auto-adjust current flow. The use of a multi-wavelength approach has resulted in simultaneous microvascular perfusion monitoring at various tissue depths, which is an added benefit for specific clinical applications. A synchronous detection algorithm to extract weak photoplethysmographic pulse-waveforms demonstrated robustness and high efficiency when applied to even small regions of 5 mm2. The experimental results showed evidences that the proposed system could achieve noticeable accuracy in blood perfusion monitoring by creating complex amplitude and phase maps for the tissue under examination.

  11. Regulation of skeletal muscle perfusion during exercise

    NASA Technical Reports Server (NTRS)

    Delp, M. D.; Laughlin, M. H.

    1998-01-01

    For exercise to be sustained, it is essential that adequate blood flow be provided to skeletal muscle. The local vascular control mechanisms involved in regulating muscle perfusion during exercise include metabolic control, endothelium-mediated control, propagated responses, myogenic control, and the muscle pump. The primary determinant of muscle perfusion during sustained exercise is the metabolic rate of the muscle. Metabolites from contracting muscle diffuse to resistance arterioles and act directly to induce vasodilation, or indirectly to inhibit noradrenaline release from sympathetic nerve endings and oppose alpha-adrenoreceptor-mediated vasoconstriction. The vascular endothelium also releases vasodilator substances (e.g., prostacyclin and nitric oxide) that are prominent in establishing basal vascular tone, but these substances do not appear to contribute to the exercise hyperemia in muscle. Endothelial and smooth muscle cells may also be involved in propagating vasodilator signals along arterioles to parent and daughter vessels. Myogenic autoregulation does not appear to be involved in the exercise hyperemia in muscle, but the rhythmic propulsion of blood from skeletal muscle veins facilitates venous return to the heart and muscle perfusion. It appears that the primary determinants of sustained exercise hyperemia in skeletal muscle are metabolic vasodilation and increased vascular conductance via the muscle pump. Additionally, sympathetic neural control is important in regulating muscle blood flow during exercise.

  12. Inhomogeneity of pulmonary perfusion during sustained microgravity

    NASA Technical Reports Server (NTRS)

    Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

    1994-01-01

    The effects of gravity on the inhomogeneity of pulmonary perfusion in man were studied by performing hyperventilation-breathhold single-breath measurements before, during and after 9 days of continuous exposure to microgravity. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase 4, were both markedly reduced. Cardiogenic oscillations were reduced to approximately 60 of their preflight standing size, while the height of phase 4 was between 0 and -8% (a terminal fall became a small terminal rise) of preflights standing. The terminal change in CO2 was nearly abolished in microgravity indicating more uniformity of blood flow between lung units that close at the end of expiration and units that remain open. This may result from the disappearance of gravity-dependent topographical inequality of blood flow. The residual cardiographic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity at a level larger than acinar.

  13. Vascular perfusion in horses with chronic laminitis.

    PubMed

    Hood, D M; Grosenbaugh, D A; Slater, M R

    1994-05-01

    Vascular perfusion casts were used to define and characterise the macroscopic perfusion defects present in the distal digit of 11 horses affected by chronic laminitis. Five clinically normal horses were used as controls. Based on clinical history and clinical status, horses with chronic laminitis were classified as being potentially treatable or clinically refractory. Eleven macroscopic vascular defects were noted in the casts from horses with laminitis. Four types of lesions were identified in the submural laminar circulation, 3 in the coronary bed and 4 were associated with the solar circulation. Multiple defects were present and a definite trend was noted for the perfusion defects to be worse in the casts of clinically refractory subjects than in those considered treatable. This information suggests that evaluation of circulatory status should add significantly to the ability to separate treatable from clinically refractory patients. Results also indicated that ventral displacement of the third phalanx (sinkers) and compression of the solar vasculature are more prevalent than is presently thought.

  14. Dynamic CT perfusion measurement in a cardiac phantom.

    PubMed

    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.

  15. Transuranic radionuclides from resuspension in the environment, a bibliography

    SciTech Connect

    Stoker, A.C.; Shinn, J.H.; Noshkin, V.E.

    1994-04-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions. An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. On the basis of our reviews, we have arbitrarily outlined five general source terms. These are fallout, fuel cycle waste, accidents, disposal sites and resuspension. Resuspension of the transuranic radionuclides is an unique source term, in that the radionuclides can originate from any of the other source terms. If these transuranic radionuclides become resuspended into the air, they then become important as a source of inhaled radionuclides. This bibliography is a compilation of the references containing studies of plutonium and americium in the environment as a result of resuspension.

  16. Mathematical simulation of sediment and radionuclide transport in estuaries

    SciTech Connect

    Onishi, Y.; Trent, D.S.

    1982-11-01

    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions.

  17. Selected radionuclides important to low-level radioactive waste management

    SciTech Connect

    1996-11-01

    The purpose of this document is to provide information to state representatives and developers of low level radioactive waste (LLW) management facilities about the radiological, chemical, and physical characteristics of selected radionuclides and their behavior in the environment. Extensive surveys of available literature provided information for this report. Certain radionuclides may contribute significantly to the dose estimated during a radiological performance assessment analysis of an LLW disposal facility. Among these are the radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha emitting transuranics with half-lives greater than 5 years). This report discusses these radionuclides and other radionuclides that may be significant during a radiological performance assessment analysis of an LLW disposal facility. This report not only includes essential information on each radionuclide, but also incorporates waste and disposal information on the radionuclide, and behavior of the radionuclide in the environment and in the human body. Radionuclides addressed in this document include technetium-99, carbon-14, iodine-129, tritium, cesium-137, strontium-90, nickel-59, plutonium-241, nickel-63, niobium-94, cobalt-60, curium -42, americium-241, uranium-238, and neptunium-237.

  18. Radionuclide and radiation protection data handbook 2nd edition (2002).

    PubMed

    Delacroix, D; Guerre, J P; Leblanc, P; Hickman, C

    2002-01-01

    This handbook is a reference source of radionuclide and radiation protection information. Its purpose is to provide users of radionuclides in medicine, research and industry with consolidated and appropriate information and data to handle and transport radioactive substances safely. It is mainly intended for users in low and intermediate activity laboratories. Individual data sheets are provided for a wide range of commonly used radionuclides (144 in total). These radionuclides are classified into five different groups as a function of risk level, represented by colours red, orange, yellow, green and blue, in descending order of risk.

  19. Transuranic radionuclides dispersed into the aquatic environment, a bibliography

    SciTech Connect

    Noshkin, V.E.; Stoker, A.C.; Wong, Kai M.

    1994-04-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions (i.e., site specific) in terrestrial, aquatic and atmospheric environments An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. On the basis of our reviews, we have arbitrarily outlined five general source terms. These are fallout, fuel cycle waste, accidents, disposal sites and resuspension. Resuspension of the transuranic radionuclides is a unique source term, in that the radionuclides can originate from any of the other source terms. If these transuranic radionuclides become resuspended into the air, they then become important as a source of inhaled radionuclides.

  20. Is oxidative stress primarily involved in reperfusion injury of the ischemic heart

    SciTech Connect

    Nohl, H.; Stolze, K.; Napetschnig, S.; Ishikawa, T. )

    1991-01-01

    Reperfusion injury of ischemic organs is suggested to result from metabolic derangements initiating an imbalanced formation of free oxygen radicals. Most investigators in this field have used the spin-trap 5,5'-dimethyl-N-pyrroline-N-oxide (DMPO) to stabilize these short-lived radicals and make them visible by means of the electron spin resonance (ESR) technique. ESR signals obtained from intravascular DMPO were reported to indicate the formation of free OH. radicals and, in some cases, also carbon-centered radicals. We were unable to confirm these findings. Carbon-centered radicals were not obtained irrespectively of conditions studied, while oxygen-centered DMPO-adducts could only be detected in minor amounts. Instead, we observed an ascorbyl-related ESR signal. The addition of ethylenediaminetetraacetic acid (EDTA), which was used by many investigators in this field, was found to greatly influence ESR-spectra of the reperfusion fluid. The ascorbyl radical concentration was clearly reduced and the DMPO-OH. adduct became more prominent. The addition of iron further stimulated this change eliciting a Fenton-type reaction responsible for DMPO-OH.-related ESR spectra in the perfusate after ischemia. Accordingly, we observed the release of iron and ascorbic acid into the perfusate as a consequence of ischemia. We could demonstrate that iron in the presence of ascorbate and EDTA causes both types of radicals detected in the perfusate. DMPO-OH. generation in the presence of EDTA was found to result from free OH. radicals that were not generated in the absence of EDTA.

  1. Early recovery of microvascular perfusion induced by t-PA in combination with abciximab or eptifibatide during postischemic reperfusion

    PubMed Central

    Bertuglia, Silva; Giusti, Andrea

    2002-01-01

    Background GPIIb/IIIa inhibitors abciximab and eptifibatide have been shown to inhibit platelet aggregation in ischemic heart disease. Our aim was to test the efficacy of abiciximab (Reo Pro) or eptifibatide (Integrilin) alone or in combination with plasminogen activator (t-PA) in an experimental model of ischemia reperfusion (I/R) in hamster cheek pouch microcirculation visualized by fluorescence microscopy. Hamsters were treated with saline, or abiciximab or eptifibatide or these drugs combined with t-PA infused intravenously 10 minutes before ischemia and through reperfusion. We measured the microvessel diameter changes, the arteriolar red blood cell (RBC) velocity, the increase in permeability, the perfused capillary length (PCL), and the platelet and leukocyte adhesion on microvessels. Results I/R elicited large increases in the platelet and leukocyte adhesion and a decrease in microvascular perfusion. These responses were significantly attenuated by abiciximab or eptifibatide (PCL:70 and 65% at 5–10 mins of reperfusion and 85 and 87% at 30 mins of reperfusion, respectively, p < 0.001) while t-PA combined with abiciximab or eptifibatide, was more effective and microvascular perfusion recovered immediately after postischemic reperfusion. Conclusions Platelets are crucial in I/R injury, as shown by the treatment with abicixmab or eptifibatide, which decreased platelet aggregation in microvessels, and also decreased leukocyte adhesion in venules. Arterial vasoconstriction, decreased arterial RBC velocity and alterations in the endothelial barrier with increased permeability delayed the complete restoration of blood flow, while t-PA combined with inhibition of platelet aggregation speeded up the capillary perfusion after reperfusion. PMID:12086588

  2. Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT

    PubMed Central

    2010-01-01

    Background To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress. Methods 43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR. Patients then underwent in-room exercise stress using a partially modified treadmill. 12-lead ECG monitoring was performed throughout. At peak stress, Tc99m was injected and patients rapidly returned to their prior position in the magnet for post-exercise cine and perfusion imaging. The patient table was pulled out of the magnet for recovery monitoring. The patient was sent back into the magnet for recovery cine and resting perfusion followed by delayed post-gadolinium imaging. Post-CMR, patients went to the adjacent SPECT lab to complete stress nuclear imaging. Each modality's images were reviewed blinded to the other's results. Results Patients completed on average 9.3 ± 2.4 min of the Bruce protocol. Stress cine CMR was completed in 68 ± 14 sec following termination of exercise, and stress perfusion CMR was completed in 88 ± 8 sec. Agreement between SPECT and CMR was moderate (κ = 0.58). Accuracy in eight patients who underwent coronary angiography was 7/8 for CMR and 5/8 for SPECT (p = 0.625). Follow-up at 6 months indicated freedom from cardiovascular events in 29/29 CMR-negative and 33/34 SPECT-negative patients. Conclusions Exercise stress CMR including wall motion and perfusion is feasible in patients with suspected ischemic heart disease. Larger clinical trials are warranted based on the promising results of this pilot study to allow comparative effectiveness studies of this stress imaging system vs. other stress imaging modalities. PMID:20624294

  3. Visualizing plumes of heavy metals and radionuclides

    NASA Astrophysics Data System (ADS)

    Prigiobbe, V.; Liu, T.; Bryant, S. L.; Hesse, M. A.

    2015-12-01

    The understanding of the transport behaviors in porous media resides on the ability to reproduce fundamental phenomena in a lab setting. Experiments with quasi 2D tanks filled with beads are performed to study physical phenomena induced by chemical and fluid dynamic processes. When an alkaline solution containing heavy metals or radionuclides invades a low pH region, mixing due to longitudinal dispersion induces destabilization of the front forming a fast travelling pulse [1]. When the two fluids travel in parallel, instead, mixing induced by transverse dispersion creates a continuous leakage from the alkaline region into the acidic one forming a fast travelling plume [2] (Figure 1). Impact of these phenomena are on aquifers upon leaking of alkaline fluids, rich in heavy metals and radionuclides, from waste storage sites. Here, we report the results from a study where experiments with a quasi 2D tank are performed to analyze the effect of transverse mixing on strontium (Sr2+) transport. To visualize the leaking plume, a fluorescent dye (Fura-2) is added the acidic solution, which has been widely used in biomedical applications [3]. It is the aim of this work to optimize its application under the conditions relevant to this work. Spectrometric measurements of absorption and fluorescence show sensitivity of the dye to the presence of Sr2+ throughout a broad range of pH and Sr2+ concentration (Figure 2). In the absence of Sr2+, no significant absorption and fluorescence was measured, but as Sr2+ was added the relevant peaks increase significantly and sample dilution of tenfold was required to remain within the measuring threshold. These results show a strong sensitivity of the dye to the cation opening the opportunity to use Fura-2 as a tool to visualize heavy metals and radionuclides plumes. References[1] Prigiobbe et al. (2012) GRL 39, L18401. [2] Prigiobbe and Hesse (2015) in preparation. [3] Xu-Friedman and Regehr (2000) J. Neurosci. 20(12) 4414-4422.

  4. Method of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, Lane A.; Ryan, Jack L.

    1999-01-01

    The present invention is a method of removing an impurity of plutonium, lead or a combination thereof from a mixture of radionuclides that contains the impurity and at least one parent radionuclide. The method has the steps of (a) insuring that the mixture is a hydrochloric acid mixture; (b) oxidizing the acidic mixture and specifically oxidizing the impurity to its highest oxidation state; and (c) passing the oxidized mixture through a chloride form anion exchange column whereupon the oxidized impurity absorbs to the chloride form anion exchange column and the 22.sup.9 Th or 2.sup.27 Ac "cow" radionuclide passes through the chloride form anion exchange column. The plutonium is removed for the purpose of obtaining other alpha emitting radionuclides in a highly purified form suitable for medical therapy. In addition to plutonium; lead, iron, cobalt, copper, uranium, and other metallic cations that form chloride anionic complexes that may be present in the mixture; are removed from the mixture on the chloride form anion exchange column.

  5. Method of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, L.A.; Ryan, J.L.

    1999-03-23

    The present invention is a method of removing an impurity of plutonium, lead or a combination thereof from a mixture of radionuclides that contains the impurity and at least one parent radionuclide. The method has the steps of (a) insuring that the mixture is a hydrochloric acid mixture; (b) oxidizing the acidic mixture and specifically oxidizing the impurity to its highest oxidation state; and (c) passing the oxidized mixture through a chloride form anion exchange column whereupon the oxidized impurity absorbs to the chloride form anion exchange column and the {sup 229}Th or {sup 227}Ac ``cow`` radionuclide passes through the chloride form anion exchange column. The plutonium is removed for the purpose of obtaining other alpha emitting radionuclides in a highly purified form suitable for medical therapy. In addition to plutonium, lead, iron, cobalt, copper, uranium, and other metallic cations that form chloride anionic complexes that may be present in the mixture are removed from the mixture on the chloride form anion exchange column. 8 figs.

  6. Sustainable production of orphan radionuclides at Wisconsin.

    PubMed

    Nickles, R J; Avila-Rodriguez, M A; Nye, J A; Houser, E N; Selwyn, R G; Schueller, M J; Christian, B T; Jensen, M

    2008-06-01

    Over a hundred proton-induced reactions have been studied at the University of Wisconsin Medical Physics department since the installation of the first CTI RDS 112 in 1985. The focus has been to measure thick target yields at 11 MeV, in an effort to concentrate on the practical production of positron emitting radionuclides that have favorable decay characteristics, high yields and the potential for labeling pivotal biological tracers. This review covers our recent advances to scale-up the production of the heavy halogens and transition metals as feed-stock for non-conventional PET tracers that are currently attracting increased attention in oncology.

  7. Research remote laser methods for radionuclides monitoring

    NASA Astrophysics Data System (ADS)

    Kascheev, S. V.; Elizarov, Valentin V.; Grishkanich, Alexander S.; Bespalov, V. G.; Vasil'ev, Sergey K.; Zhevlakov, A. P.

    2014-05-01

    Laser sensing can serve as a highly effective method of searching and monitoring of radioactive contamination. The first method is essence consists in definition the Sr90 and Сs137 concentration by excitation and registration of fluorescence at wavelength of λ = 0.347÷7.0 μm at laser sounding. The second method experiments were carried out under the Raman-scattering circuit. Preliminary results of investigation show the real possibility to register of leakage of a radionuclide with concentration at level of 108÷109 сm-3 on a safe distance from the infected object.

  8. Radionuclides at Descartes in the central highlands

    NASA Technical Reports Server (NTRS)

    Wrigley, R. C.

    1973-01-01

    Throium, uranium, potassium, aluminium-26, and sodium-22 were measured by nondestructive gamma ray spectrometry in six soil and two rock samples gathered by Apollo 16 in the lunar central highlands. The soil samples probably include both major geologic formations in the vicinity, the Cayley and Descartes Formations, although it is possible that the Descartes Formation is not represented. The rock samples have low concentrations of primordial radionuclides. The Al concentrations were lower than could be expected from the high abundance of alumina in the Apollo 16 soils reported earlier, but this could be due to lower concentrations of target elements in these soils, sampling depth variations, or regolithic mixing (exposure age variations).

  9. Radionuclides in the Great Lakes basin.

    PubMed Central

    Ahier, B A; Tracy, B L

    1995-01-01

    The Great Lakes basin is of radiologic interest due to the large population within its boundaries that may be exposed to various sources of ionizing radiation. Specific radionuclides of interest in the basin arising from natural and artificial sources include 3H, 14C, 90Sr, 129I, 131I, 137Cs, 222Rn, 226Ra, 235U, 238U, 239Pu, and 241Am. The greatest contribution to total radiation exposure is the natural background radiation that provides an average dose of about 2.6 mSv/year to all basin residents. Global fallout from atmospheric nuclear weapons tests conducted before 1963 has resulted in the largest input of anthropogenic radioactivity into the lakes. Of increasing importance is the radionuclide input from the various components of the nuclear fuel cycle. Although the dose from these activities is currently very low, it is expected to increase if there is continued growth of the nuclear industry. In spite of strict regulations on design and operation of nuclear power facilities, the potential exists for a serious accident as a result of the large inventories of radionuclides contained in the reactor cores; however, these risks are several orders of magnitude less than the risks from other natural and man-made hazards. An area of major priority over the next few decades will be the management of the substantial amounts of radioactive waste generated by nuclear fuel cycle activities. Based on derived risk coefficients, the theoretical incidence of fatal and weighted nonfatal cancers and hereditary defects in the basin's population, attributable to 50 years of exposure to natural background radiation, is conservatively estimated to be of the order of 3.4 x 10(5) cases. The total number of attributable health effects to the year 2050 from fallout radionuclides in the Great Lakes basin is of the order of 5.0 x 10(3). In contrast, estimates of attributable health effects from 50 years of exposure to current nuclear fuel cycle effluent in the basin are of the order of 2

  10. Detection of gastrointestinal bleeding by radionuclide scintigraphy

    SciTech Connect

    Gupta, S.; Luna, E.; Kingsley, S.; Prince, M.; Herrera, N.

    1984-01-01

    Scanning with Technetium /sup 99m/ labeled autologous red blood cells was performed in 59 patients with clinical suspicion of acute and/or intermittent, chronic gastrointestinal bleeding. In 36 patients (61%), a definite site of bleeding could be demonstrated. A strong correlation with other modalities such as upper and lower gastrointestinal endoscopy, contrast angiography, and surgical exploration was found. Overall sensitivity of the procedure was 91%; specificity 100% and accuracy 93.3%. It is suggested that radionuclide scintigraphy provides a completely noninvasive, simple, and sensitive procedure which may be routinely used for the detection and localization of gastrointestinal bleeding.

  11. Natural contamination in radionuclide detection systems

    SciTech Connect

    Wogman, N.A.

    1980-10-01

    Through the use of low-level gamma-ray spectrometry, clean material for construction of radionuclide detection systems has been identified. In general aluminum contains high quantities of /sup 232/Th and /sup 238/U with minimal quantities of /sup 40/K. Stainless steels contain /sup 60/Co. The radioactive contents of foams, cements, and light reflective materials are quite variable. Molecular sieve materials used in germanium spectrometers contain from 4-9 dpm/g. Only through a judicious choice of materials can a spectrometer with the lowest achievable background be assembled.

  12. Measurement of radionuclides in waste packages

    SciTech Connect

    Brodzinski, R.L.; Perkins, R.W.; Rieck, H.G.; Wogman, N.A.

    1986-10-14

    A method is described for non-destructively assaying the radionuclide content of solid waste in a sealed container comprising: (a) determining the type of reactor responsible for the generation of the waste; (b) determining the degree of fuel enrichment of the reactor; (c) determining the decay time of the waste since exposure in the reactor; (d) measuring the gamma-ray spectrum of the waste; (e) determining the matrix density of the waste from ratios of photopeak pairs from individual radioisotopes in the gamma-ray spectrum; (f) measuring the total neutron flux and the coincidence neutron flux of the waste; and (g) determining neutron multiplicity from the coincidence neutron flux.

  13. Preparation of radiopharmaceuticals labeled with metal radionuclides

    SciTech Connect

    Welch, M.J.

    1992-06-01

    We recently developed a useful zinc-62/copper-62 generator and are presently evaluating copper-62 radiopharmaceuticals for clinical studies. While developing these copper-62 radiopharmaceuticals, in collaboration with the University of Missouri Research Reactor, Columbia we have also explored copper-64 radiopharmaceuticals. The PET images we obtained with copper-64 tracers were of such high quality that we have developed and evaluated copper-64 labeled antibodies for PET imaging. The major research activities described herein include: the development and assessment of gallium-68 radiopharmaceuticals; the development and evaluation of a new zinc-62/copper-62 generator and the assessment of copper-62 radiopharmaceuticals; mechanistic studies on proteins labeled with metal radionuclides.

  14. Radionuclide partitioning across great lakes natural interfaces

    NASA Astrophysics Data System (ADS)

    Platford, R. F.; Joshi, S. R.

    1989-11-01

    Several water and surface microlayer samples from Lake St. Clair, the Niagara River, and the North Shore of Lake Ontario collected during 1983 1986 have been assayed for a variety of radionuclides. In addition, the foam accumulating in the pool just below Niagara Falls was also analyzed and found to be the most efficient aqueous phase collector of137Cs,210Pb, and226Ra. The order of radioisotope specific activities from highest to lowest is: Lake Ontario sediment, Niagara River suspended solids, Niagara River foam, surface microlayer water, and subsurface water. Radiological dose rates to the sediments from137Cs,226Ra, and228Th total about 5 mGy/y.

  15. [Radionuclides for metastatic bone pain palliation].

    PubMed

    Lass, Piotr

    2002-10-01

    The paper overviews the role of systemic radionuclide therapy in patients with disseminated bone metastases. Most patients with bone metastases experience painful symptoms. Systemic radioisotope therapy is an alternative to traditional hemibody radiation in cases of multiple, diffuse metastases. Usually given as a single i.v. slow infusion it provides a pain relief beginning in one to three weeks, with a mean duration up to several months, depending on the kind of radioisotope applied. The paper overviews the role of unsealed source therapy with these bone-seeking radiopharmaceuticals in palliating pain, improving quality of life, indications, contraindications and complications of this therapy are discussed, as well as cost-benefit aspects.

  16. Radionuclide evaluation of nonmalignant bone disorders

    SciTech Connect

    Winzelberg, G.G.

    1983-02-01

    Recent advances in nuclear imaging have improved the noninvasive evaluation of patients with nonmalignant bone disorders. When bone scanning agents are combined with bone marrow scanning agents and gallium-67 scintigraphy, a more accurate diagnosis can be obtained. By selecting the appropriate imaging sequence, it is often possible to distinguish cellulitis from underlying osteomyelitis. In patients with total hip replacements, it may be possible to separate postsurgical changes from prosthetic loosening or infection. Stress fractures in joggers may be detected by radionuclide bone scintigraphy before radiographs become abnormal. These nuclear imaging procedures can be done in most hospitals.

  17. Selective laser ionisation of radionuclide 63Ni

    NASA Astrophysics Data System (ADS)

    Tsvetkov, G. O.; D’yachkov, A. B.; Gorkunov, A. A.; Labozin, A. V.; Mironov, S. M.; Firsov, V. A.; Panchenko, V. Ya.

    2017-02-01

    We report a search for a scheme of selective laser stepwise ionisation of radionuclide 63Ni by radiation of a dye laser pumped by a copper vapour laser. A three-stage scheme is found with ionisation through an autoionising state (AIS): 3d 84s2 3F4(E = 0) → 3d 94p 1Fo3(31030.99 cm‑1) → 3d 94d 2[7/2]4(49322.56 cm‑1) → AIS(67707.61 cm‑1) which, by employing saturated radiation intensities provides the ionisation selectivity of above 1200 for 63Ni.

  18. Comparative study of DSC-PWI and 3D-ASL in ischemic stroke patients.

    PubMed

    Zhang, Shui-xia; Yao, Yi-hao; Zhang, Shun; Zhu, Wen-jie; Tang, Xiang-yu; Qin, Yuan-yuan; Zhao, Ling-yun; Liu, Cheng-xia; Zhu, Wen-zhen

    2015-12-01

    The purpose of this study was to quantitatively analyze the relationship between three dimensional arterial spin labeling (3D-ASL) and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI) in ischemic stroke patients. Thirty patients with ischemic stroke were included in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging (DWI), magnetic resonance angiography (MRA), 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest (ROIs) were drawn on the cerebral blood flow (CBF) maps (derived from ASL) and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time (MTT) were calculated. The relationships between ASL and DSC parameters were analyzed using Pearson's correlation analysis. Receiver operative characteristic (ROC) curves were performed to define the thresholds of relative value of ASL-CBF (rASL) that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients (R) values being 0.611 (P<0.001) and-0.610 (P<0.001) respectively. ROC curves demonstrated that when rASL ≤0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF<0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL ≤0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT>1.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters (DSC-CBF and MTT) in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. If rASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.

  19. Perfusion phantom: An efficient and reproducible method to simulate myocardial first-pass perfusion measurements with cardiovascular magnetic resonance.

    PubMed

    Chiribiri, Amedeo; Schuster, Andreas; Ishida, Masaki; Hautvast, Gilion; Zarinabad, Niloufar; Morton, Geraint; Otton, James; Plein, Sven; Breeuwer, Marcel; Batchelor, Philip; Schaeffter, Tobias; Nagel, Eike

    2013-03-01

    The aim of this article is to describe a novel hardware perfusion phantom that simulates myocardial first-pass perfusion allowing comparisons between different MR techniques and validation of the results against a true gold standard. MR perfusion images were acquired at different myocardial perfusion rates and variable doses of gadolinium and cardiac output. The system proved to be sensitive to controlled variations of myocardial perfusion rate, contrast agent dose, and cardiac output. It produced distinct signal intensity curves for perfusion rates ranging from 1 to 10 mL/mL/min. Quantification of myocardial blood flow by signal deconvolution techniques provided accurate measurements of perfusion. The phantom also proved to be very reproducible between different sessions and different operators. This novel hardware perfusion phantom system allows reliable, reproducible, and efficient simulation of myocardial first-pass MR perfusion. Direct comparison between the results of image-based quantification and reference values of flow and myocardial perfusion will allow development and validation of accurate quantification methods.

  20. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    SciTech Connect

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L.

    1981-01-01

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.