Correlation of intra-tumor 18F-FDG uptake heterogeneity indices with perfusion CT derived parameters in colorectal cancer.

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Tixier, Florent; Groves, Ashley M; Goh, Vicky; Hatt, Mathieu; Ingrand, Pierre; Le Rest, Catherine Cheze; Visvikis, Dimitris

2014-01-01

Thirty patients with proven colorectal cancer prospectively underwent integrated 18F-FDG PET/DCE-CT to assess the metabolic-flow phenotype. Both CT blood flow parametric maps and PET images were analyzed. Correlations between PET heterogeneity and perfusion CT were assessed by Spearman's rank correlation analysis. Blood flow visualization provided by DCE-CT images was significantly correlated with 18F-FDG PET metabolically active tumor volume as well as with uptake heterogeneity for patients with stage III/IV tumors (|ρ|:0.66 to 0.78; p-valueheterogeneity of 18F-FDG PET accumulation reflects to some extent tracer distribution and consequently indicates that 18F-FDG PET intra-tumor heterogeneity may be associated with physiological processes such as tumor vascularization.

Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level

International Nuclear Information System (INIS)

Bryant, Mark; Kauczor, Hans-Ulrich; Ley, Sebastian; Eberhardt, Ralf; Herth, Felix; Menezes, Ravi; Sedlaczek, Oliver; Ley-Zaporozhan, Julia

2015-01-01

Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns. Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage. 730 segments were evaluated. CT categorized 566 (78 %) as centrilobular, 159 (22 %) as panlobular and 5 (<1 %) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4 %); 4-425 (58 %); 5-169 (23 %); 6-108 (15 %). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42 % panlobular - homogeneous absence of perfusion (score 5); and 43 % panlobular - heterogeneous absence of perfusion (score 6). MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema. (orig.)

Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level

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Bryant, Mark; Kauczor, Hans-Ulrich [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Ley, Sebastian [Chirurgische Klinik Dr. Rinecker, Department of Diagnostic and Interventional Radiology, Munich (Germany); Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany); Eberhardt, Ralf; Herth, Felix [Thoraxklinik University of Heidelberg, Department of Pneumology and Critical Care Medicine, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Menezes, Ravi [University of Toronto, Medical Imaging, Toronto (Canada); Sedlaczek, Oliver [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); German Cancer Research Center, Department of Radiology, Heidelberg (Germany); Member of German Lung Research Center DZL, Translational Lung Research Center TLRC-H, Heidelberg (Germany); Ley-Zaporozhan, Julia [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany)

2015-01-15

Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns. Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage. 730 segments were evaluated. CT categorized 566 (78 %) as centrilobular, 159 (22 %) as panlobular and 5 (<1 %) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4 %); 4-425 (58 %); 5-169 (23 %); 6-108 (15 %). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42 % panlobular - homogeneous absence of perfusion (score 5); and 43 % panlobular - heterogeneous absence of perfusion (score 6). MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema. (orig.)

Assessment of smoking-induced impairment of pulmonary perfusion using three-dimensional SPECT images

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Miyasaka, Takashi [Toho Univ., Tokyo (Japan). School of Medicine

1997-09-01

The effects of smoking on ventilation-perfusion lung scintigrams were investigated. The subjects comprised 40 healthy males (28 smokers and 12 nonsmokers) without a history of cardiopulmonary disease and with normal chest radiographs. After acquisition of planar images of ventilation lung scintigrams with 370 MBq of {sup 133}Xe gas, planar images and SPECT images of pulmonary perfusion flow were obtained using 185 MBq of {sup 99m}Tc-MAA. Planar imaging showed perfusion defects in only 5 smokers. In contrast, 16 subjects were found to have perfusion defects on SPECT images (p<0.05), indicating the usefulness of SPECT images in detecting minor vascular damage of the lung. Although perfusion defects were common in the smokers (p<0.05), their relationship to the BRINKMAN index was uncertain. The perfusion defects found in the smokers were nonsegmental and commonly involved the right upper lobe. Ventilation scans revealed only delayed washout of {sup 133}Xe in 4 smokers, suggesting that smoking-induced abnormal perfusion on SPECT appears earlier than impaired ventilation on scintigrams. (author)

Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

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Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Monbaron, David; Ruiz, Juan [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland); Koehli, Melanie [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland)

2005-01-01

Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, {sup 99m}Tc-sestamibi, {sup 201}Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS{>=}4) was observed in 49 (37%) patients (SSS=4.9{+-}8.4, SDS=2.4{+-}4.7), reversible perfusion defects (SDS{>=}2) in 40 (30%) patients [SSS=13.3{+-}10.9; SDS=8.0{+-}5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9{+-}11.3; SDS=7.4{+-}1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify

High fat diet-induced glucose intolerance impairs myocardial function, but not myocardial perfusion during hyperaemia: a pilot study

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van den Brom Charissa E

2012-06-01

Full Text Available Abstract Background Glucose intolerance is a major health problem and is associated with increased risk of progression to type 2 diabetes mellitus and cardiovascular disease. However, whether glucose intolerance is related to impaired myocardial perfusion is not known. The purpose of the present study was to study the effect of diet-induced glucose intolerance on myocardial function and perfusion during baseline and pharmacological induced hyperaemia. Methods Male Wistar rats were randomly exposed to a high fat diet (HFD or control diet (CD (n = 8 per group. After 4 weeks, rats underwent an oral glucose tolerance test. Subsequently, rats underwent (contrast echocardiography to determine myocardial function and perfusion during baseline and dipyridamole-induced hyperaemia (20 mg/kg for 10 min. Results Four weeks of HFD feeding resulted in glucose intolerance compared to CD-feeding. Contractile function as represented by fractional shortening was not altered in HFD-fed rats compared to CD-fed rats under baseline conditions. However, dipyridamole increased fractional shortening in CD-fed rats, but not in HFD-fed rats. Basal myocardial perfusion, as measured by estimate of perfusion, was similar in CD- and HFD-fed rats, whereas dipyridamole increased estimate of perfusion in CD-fed rats, but not in HFD-fed rats. However, flow reserve was not different between CD- and HFD-fed rats. Conclusions Diet-induced glucose intolerance is associated with impaired myocardial function during conditions of hyperaemia, but myocardial perfusion is maintained. These findings may result in new insights into the effect of glucose intolerance on myocardial function and perfusion during hyperaemia.

Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

International Nuclear Information System (INIS)

Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika; Monbaron, David; Ruiz, Juan; Koehli, Melanie

2005-01-01

Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, 99m Tc-sestamibi, 201 Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS≥4) was observed in 49 (37%) patients (SSS=4.9±8.4, SDS=2.4±4.7), reversible perfusion defects (SDS≥2) in 40 (30%) patients [SSS=13.3±10.9; SDS=8.0±5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9±11.3; SDS=7.4±1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a

Myocardial Perfusion and Function Are Distinctly Altered by Sevoflurane Anesthesia in Diet-Induced Prediabetic Rats.

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van den Brom, Charissa E; Boly, Chantal A; Bulte, Carolien S E; van den Akker, Rob F P; Kwekkeboom, Rick F J; Loer, Stephan A; Boer, Christa; Bouwman, R Arthur

2016-01-01

Preservation of myocardial perfusion during surgery is particularly important in patients with increased risk for perioperative complications, such as diabetes. Volatile anesthetics, like sevoflurane, have cardiodepressive effects and may aggravate cardiovascular complications. We investigated the effect of sevoflurane on myocardial perfusion and function in prediabetic rats. Rats were fed a western diet (WD; n = 18) or control diet (CD; n = 18) for 8 weeks and underwent (contrast) echocardiography to determine perfusion and function during baseline and sevoflurane exposure. Myocardial perfusion was estimated based on the product of microvascular filling velocity and blood volume. WD-feeding resulted in a prediabetic phenotype characterized by obesity, hyperinsulinemia, hyperlipidemia, glucose intolerance, and hyperglycemia. At baseline, WD-feeding impaired myocardial perfusion and systolic function compared to CD-feeding. Exposure of healthy rats to sevoflurane increased the microvascular filling velocity without altering myocardial perfusion but impaired systolic function. In prediabetic rats, sevoflurane did also not affect myocardial perfusion; however, it further impaired systolic function. Diet-induced prediabetes is associated with impaired myocardial perfusion and function in rats. While sevoflurane further impaired systolic function, it did not affect myocardial perfusion in prediabetic rats. Our findings suggest that sevoflurane anesthesia leads to uncoupling of myocardial perfusion and function, irrespective of the metabolic state.

Relation between exercise-induced ventricular arrhythmias and myocardial perfusion abnormalities in patients with intermediate pretest probability of coronary artery disease

International Nuclear Information System (INIS)

Elhendy, A.; Sozzi, F.B.; Van Domburg, R.T.; Bax, J.J.; Roelandt, J.R.T.C.

2000-01-01

We studied 302 patients (mean age 54±9 years, 152 men and 150 women) with intermediate pretest probability of CAD (range=0.25- 0.80, mean=0.43±0.20) by upright bicycle exercise stress test in conjunction with technetium-99m single-photon emission tomography (SPET) imaging. Exercise-induced VAs (frequent or complex premature ventricular contractions or ventricular tachycardia) occurred in 65 patients (22%). No significant difference was found between patients with and patient without VAs regarding the pretest probability of CAD (0.45±0.21 vs 0.43±0.20). Patients with exercise-induced VAs had a higher prevalence of perfusion abnormalities (52% vs 26%, P=0.002) and ischaemic electrocardiographic changes (31% vs 16%, P<0.05) compared to patients without VAs. A higher prevalence of perfusion abnormalities in patients with VAs was observed in both men (67% vs 35%, P<0.01) and women (38% vs 16%, P<0.05). However, the positive predictive value of exercise-induced VAs for the presence of myocardial perfusion abnormalities was higher in men than in women (67% vs 38%, P<0.05). The presence of abnormal myocardial perfusion was the only independent predictor of exercise-induced VAs (OR 2.2; 95% CI, 1.2-4.2) by multivariate analysis of clinical and stress test variables. It is concluded that in patients with intermediate pretest probability of CAD, exercise-induced VAs are predictive of a higher prevalence of myocardial perfusion abnormalities in both men and women. However, the positive predictive value of exercise-induced VAs for perfusion abnormalities is higher in men. Because of the underestimation of ischaemia by electrocardiographic changes, exercise-induced VAs should be interpreted as a marker of a higher probability of CAD. (orig./MG) (orig.)

Investigation of the mechanisms mediating MDMA "Ecstasy"-induced increases in cerebro-cortical perfusion determined by btASL MRI.

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Rouine, J; Kelly, M E; Jennings-Murphy, C; Duffy, P; Gorman, I; Gormley, S; Kerskens, C M; Harkin, Andrew

2015-05-01

Acute administration of the recreational drug of abuse 3,4-methylenedioxymethamphetamine (MDMA; Ecstasy) has previously been shown to increase cerebro-cortical perfusion as determined by bolus-tracking arterial spin labelling (btASL) MRI. The purpose of the current study was to assess the mechanisms mediating these changes following systemic administration of MDMA to rats. Pharmacological manipulation of serotonergic, dopaminergic and nitrergic transmission was carried out to determine the mechanism of action of MDMA-induced increases in cortical perfusion using btASL MRI. Fenfluramine (10 mg/kg), like MDMA (20 mg/kg), increased cortical perfusion. Increased cortical perfusion was not obtained with the 5-HT2 receptor agonist 2,5-dimethoxy-4-iodophenyl-aminopropane hydrochloride (DOI) (1 mg/kg). Depletion of central 5-HT following systemic administration of the tryptophan hydroxylase inhibitor para-chlorophenylalanine (pCPA) produced effects similar to those observed with MDMA. Pre-treatment with the 5-HT receptor antagonist metergoline (4 mg/kg) or with the 5-HT reuptake inhibitor citalopram (30 mg/kg), however, failed to produce any effect alone or influence the response to MDMA. Pre-treatment with the dopamine D1 receptor antagonist SCH 23390 (1 mg/kg) failed to influence the changes in cortical perfusion obtained with MDMA. Treatment with the neuronal nitric oxide (NO) synthase inhibitor 7-nitroindazole (7-NI) (25 mg/kg) provoked no change in cerebral perfusion alone yet attenuated the MDMA-related increase in cortical perfusion. Cortical 5-HT depletion is associated with increases in perfusion although this mechanism alone does not account for MDMA-related changes. A role for NO, a key regulator of cerebrovascular perfusion, is implicated in MDMA-induced increases in cortical perfusion.

Radiation-Induced Reductions in Regional Lung Perfusion: 0.1-12 Year Data From a Prospective Clinical Study

International Nuclear Information System (INIS)

Zhang Junan; Ma Jinli; Zhou Sumin; Hubbs, Jessica L.; Wong, Terence Z.; Folz, Rodney J.; Evans, Elizabeth S.; Jaszczak, Ronald J.; Clough, Robert; Marks, Lawrence B.

2010-01-01

Purpose: To assess the time and regional dependence of radiation therapy (RT)-induced reductions in regional lung perfusion 0.1-12 years post-RT, as measured by single photon emission computed tomography (SPECT) lung perfusion. Materials/Methods: Between 1991 and 2005, 123 evaluable patients receiving RT for tumors in/around the thorax underwent SPECT lung perfusion scans before and serially post-RT (0.1-12 years). Registration of pre- and post-RT SPECT images with the treatment planning computed tomography, and hence the three-dimensional RT dose distribution, allowed changes in regional SPECT-defined perfusion to be related to regional RT dose. Post-RT follow-up scans were evaluated at multiple time points to determine the time course of RT-induced regional perfusion changes. Population dose response curves (DRC) for all patients at different time points, different regions, and subvolumes (e.g., whole lungs, cranial/caudal, ipsilateral/contralateral) were generated by combining data from multiple patients at similar follow-up times. Each DRC was fit to a linear model, and differences statistically analyzed. Results: In the overall groups, dose-dependent reductions in perfusion were seen at each time post-RT. The slope of the DRC increased over time up to 18 months post-RT, and plateaued thereafter. Regional differences in DRCs were only observed between the ipsilateral and contralateral lungs, and appeared due to tumor-associated changes in regional perfusion. Conclusions: Thoracic RT causes dose-dependent reductions in regional lung perfusion that progress up to ∼18 months post-RT and persists thereafter. Tumor shrinkage appears to confound the observed dose-response relations. There appears to be similar dose response for healthy parts of the lungs at different locations.

Ventilation and Perfusion Lung Scintigraphy of Allergen-Induced Airway Responses in Atopic Asthmatic Subjects

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Krishnan Parameswaran

2007-01-01

Full Text Available BACKGROUND: Both ventilation (V and perfusion (Q of the lungs are altered in asthma, but their relationships with allergen-induced airway responses and gas exchange are not well described.

Effect of endobronchial valve therapy on pulmonary perfusion and ventilation distribution.

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Carmen Pizarro

Full Text Available Endoscopic lung volume reduction (ELVR is an emerging therapy for emphysematous COPD. However, any resulting changes in lung perfusion and ventilation remain undetermined. Here, we report ELVR-mediated adaptations in lung perfusion and ventilation, as investigated by means of pulmonary scintigraphy.In this observational study, we enrolled 26 patients (64.9 ± 9.4 yrs, 57.7% male with COPD heterogeneous emphysema undergoing ELVR with endobronchial valves (Zephyr, Pulmonx, Inc.. Mean baseline FEV1 and RV were 32.9% and 253.8% predicted, respectively. Lung scintigraphy was conducted prior to ELVR and eight weeks thereafter. Analyses of perfusion and ventilation shifts were performed and complemented by correlation analyses between paired zones.After ELVR, target zone perfusion showed a mean relative reduction of 43.32% (p<0.001, which was associated with a significant decrease in target zone ventilation (p<0.001. Perfusion of the contralateral untreated zone and of the contralateral total lung exhibited significant increases post-ELVR (p = 0.002 and p = 0.005, respectively; both correlated significantly with the corresponding target zone perfusion adaptations. Likewise, changes in target zone ventilation correlated significantly with ventilatory changes in the contralateral untreated zone and the total contralateral lung (Pearson's r: -0.42, p = 0.04 and Pearson's r: -0.42, p = 0.03, respectively. These effects were observed in case of clinical responsiveness to ELVR, as assessed by changes in the six-minute walk test distance.ELVR induces a relevant decrease in perfusion and ventilation of the treated zone with compensatory perfusional and ventilatory redistribution to the contralateral lung, primarily to the non-concordant, contralateral zone.

Overexpressed connective tissue growth factor in cardiomyocytes attenuates left ventricular remodeling induced by angiotensin II perfusion.

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Zhang, Ying; Yan, Hua; Guang, Gong-Chang; Deng, Zheng-Rong

2017-01-01

To evaluate the improving effects of specifically overexpressed connective tissue growth factor (CTGF) in cardiomyocytes on mice with hypertension induced by angiotensin II (AngII) perfusion, 24 transgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) were divided into two equal groups that were perfused with acetic acid and AngII, respectively, for 7 days. Another 24 cage-control wild-type C57BL/6 mice (NLC) were divided and treated identically. Blood pressure was detected by caudal artery cannulation. Cardiac structural and functional changes were observed by echocardiography. Cardiac fibrosis was detected by Masson staining. After AngII perfusion, blood pressures of NLC and Tg-CTGF mice, especially those of the formers, significantly increased. Compared with NLC + AngII group, Tg-CTGF + AngII group had significantly lower left ventricular posterior wall thickness at end-diastole and left ventricular posterior wall thickness at end-systole as well as significantly higher left ventricular end-systolic diameter and left ventricular end-diastolic diameter (P tissues (P < 0.05). Tg-CTGF can protect AngII-induced cardiac remodeling of mice with hypertension by mitigating inflammatory response. CTGF may be a therapy target for hypertension-induced myocardial fibrosis, but the detailed mechanism still needs in-depth studies.

Propofol attenuates oxidant-induced acute lung injury in an isolated perfused rabbit-lung model.

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Yumoto, Masato; Nishida, Osamu; Nakamura, Fujio; Katsuya, Hirotada

2005-01-01

Reactive oxygen species have been strongly implicated in the pathogenesis of acute lung injury (ALI). Some animal studies suggest that free radical scavengers inhibit the onset of oxidant-induced ALI. Propofol (2,6-diisopropylphenol) is chemically similar to phenol-based free radical scavengers such as the endogenous antioxidant vitamin E. Both in vivo and in vitro studies have suggested that propofol has antioxidant potential. We hypothesized that propofol may attenuate ALI by acting as a free-radical scavenger. We investigated the effects of propofol on oxidant-induced ALI induced by purine and xanthine oxidase (XO), in isolated perfused rabbit lung, in two series of experiments. In series 1, we examined the relationship between the severity of ALI and the presence of hydrogen peroxide (H2O2). In series 2, we evaluated the effects of propofol on attenuating ALI and the dose dependence of these effects. The lungs were perfused for 90 min, and we evaluated the effects on the severity of ALI by monitoring the pulmonary capillary filtration coefficient (Kfc), pulmonary arterial pressure (Ppa), and the pulmonary capillary hydrostatic pressure (Ppc). In series 1, treatment with catalase (an H2O2 scavenger) prior to the addition of purine and XO resulted in complete prevention of ALI, suggesting that H2O2 may be involved closely in the pathogenesis of ALI. In series 2, pretreatment with propofol at concentrations in excess of 0.5 mM significantly inhibited the increases in the Kfc values, and that in excess of 0.75 mM significantly inhibited the increase in the Ppa values. Propofol attenuates oxidant-induced ALI in an isolated perfused rabbit lung model, probably due to its antioxidant action.

Cryotherapy-Induced Persistent Vasoconstriction After Cutaneous Cooling: Hysteresis Between Skin Temperature and Blood Perfusion

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Khoshnevis, Sepideh; Craik, Natalie K.; Matthew Brothers, R.; Diller, Kenneth R.

2016-01-01

The goal of this study was to investigate the persistence of cold-induced vasoconstriction following cessation of active skin-surface cooling. This study demonstrates a hysteresis effect that develops between skin temperature and blood perfusion during the cooling and subsequent rewarming period. An Arctic Ice cryotherapy unit (CTU) was applied to the knee region of six healthy subjects for 60 min of active cooling followed by 120 min of passive rewarming. Multiple laser Doppler flowmetry perfusion probes were used to measure skin blood flow (expressed as cutaneous vascular conductance (CVC)). Skin surface cooling produced a significant reduction in CVC (P cryotherapy. PMID:26632263

Increased sinusoidal volume and solute extraction during retrograde liver perfusion

International Nuclear Information System (INIS)

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

1989-01-01

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

Skeletal myofiber VEGF regulates contraction-induced perfusion and exercise capacity but not muscle capillarity in adult mice.

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Knapp, Amy E; Goldberg, Daniel; Delavar, Hamid; Trisko, Breanna M; Tang, Kechun; Hogan, Michael C; Wagner, Peter D; Breen, Ellen C

2016-07-01

A single bout of exhaustive exercise signals expression of vascular endothelial growth factor (VEGF) in the exercising muscle. Previous studies have reported that mice with life-long deletion of skeletal myofiber VEGF have fewer capillaries and a severe reduction in endurance exercise. However, in adult mice, VEGF gene deletion conditionally targeted to skeletal myofibers limits exercise capacity without evidence of capillary regression. To explain this, we hypothesized that adult skeletal myofiber VEGF acutely regulates skeletal muscle perfusion during muscle contraction. A tamoxifen-inducible skeletal myofiber-specific VEGF gene deletion mouse (skmVEGF-/-) was used to reduce skeletal muscle VEGF protein by 90% in adult mice. Three weeks after inducing deletion of the skeletal myofiber VEGF gene, skmVEGF-/- mice exhibited diminished maximum running speed (-10%, P Contraction-induced perfusion measured by optical imaging during a period of electrically stimulated muscle contraction was 85% lower in skmVEGF-/- than control mice. No evidence of capillary rarefication was detected in the soleus, gastrocnemius, and extensor digitorum longus (EDL) up to 8 wk after tamoxifen-induced VEGF ablation, and contractility and fatigue resistance of the soleus measured ex vivo were also unchanged. The force-frequency of the EDL showed a small right shift, but fatigue resistance did not differ between EDL from control and skmVEGF-/- mice. These data suggest myofiber VEGF is required for regulating perfusion during periods of contraction and may in this manner affect endurance capacity. Copyright © 2016 the American Physiological Society.

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

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

2014-01-01

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

Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy.

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Eftekhari, Mohammad; Anbiaei, Robabeh; Zamani, Hanie; Fallahi, Babak; Beiki, Davood; Ameri, Ahmad; Emami-Ardekani, Alireza; Fard-Esfahani, Armaghan; Gholamrezanezhad, Ali; Seid Ratki, Kazem Razavi; Roknabadi, Alireza Momen

2015-01-01

Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right-sided cancer. To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring) were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT) to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions) over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol) was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed) and 36 patients with right-sided cancer (controls)] were enrolled. Dose-volume histogram (DVH) [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46). In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03) and anterolateral (17.1% versus 2.8%, P=0.049) walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS) of>3 was observed in twelve cases (34.3%), while in five of the controls (13.9%),(Odds ratio=1.3). There was no significant difference between the groups regarding left ventricular ejection fraction. The risk of radiation induced myocardial perfusion abnormality in patients treated with CRT on the

Exercise-induced thallium-201 myocardial perfusion defects in angina pectoris without significant coronary artery stenosis

International Nuclear Information System (INIS)

Nakazato, Masayasu; Maruoka, Yuji; Sunagawa, Osahiko; Kinjo, Kunihiko; Tomori, Masayuki; Fukiyama, Koshiro

1990-01-01

We performed exercise thallium-201 myocardial scintigraphy in 32 patients with angina pectoris to study the incidence of perfusion defects, who had no significant organic stenosis on coronary angiography. None of them had myocardial infarction or cardiomyopathy. Thallium-201 myocardial scintigraphy and 12-lead ECG recording were performed during supine bicycle ergometer exercise. Perfusion defects in thallium-201 scintigrams in SPECT images were assessed during visual analysis by two observers. In the coronary angiograms obtained during intravenous infusion of nitroglycerin, the luminal diameter of 75% stenosis or less in the AHA classification was regarded as an insignificant organic stenosis. Myocardial perfusion defects in the thallium-201 scintigrams were detected in eight (25%) of the 32 patients. Six of these eight patients had variant angina documented during spontaneous attacks with ST elevations in standard 12-lead ECGs. Perfusion defects were demonstrated at the inferior or infero-posterior regions in six patients, one of whom had concomitant anteroseptal defect. The defects were not always accompanied by chest pain. All but one patient demonstrating inferior or inferoposterior defects showed ST depression in leads II, III and aV F on their ECGs, corresponding to inferior wall ischemia. The exception was a case with right bundle branch block. Thus, 25% of the patients with angina pectoris, who had no evidence of significant organic stenosis on their coronary angiograms, exhibited exercise-induced perfusion defects in their thallium-201 scintigrams. Coronary spasms might have caused myocardial ischemia in these patients. (author)

AdVEGF-B186 and AdVEGF-DΔNΔC induce angiogenesis and increase perfusion in porcine myocardium.

Science.gov (United States)

Nurro, Jussi; Halonen, Paavo J; Kuivanen, Antti; Tarkia, Miikka; Saraste, Antti; Honkonen, Krista; Lähteenvuo, Johanna; Rissanen, Tuomas T; Knuuti, Juhani; Ylä-Herttuala, Seppo

2016-11-01

Coronary heart disease remains a significant clinical problem, and new therapies are needed especially for patients with refractory angina for whom the current therapies do not provide sufficient relief. The aim of this study was to find out if angiogenic gene therapy using new members of the vascular endothelial growth factor (VEGF) family, VEGF-B 186 and VEGF-D ΔNΔC , increase myocardial perfusion as measured by the positron emission tomography (PET) 15 O-imaging, and whether there would be coronary steal effect to the contralateral side. Furthermore, safety of intramyocardial angiogenic adenoviral gene transfer was evaluated. Intramyocardial adenoviral (Ad) VEGF-B 186 or AdVEGF-D ΔNΔC gene transfers were given endovascularly into the porcine posterolateral wall of the left ventricle (n=34). Six days later, PET 15 O-imaging for myocardial perfusion and coronary angiography were performed. AdVEGF-B 186 and AdVEGF-D ΔNΔC induced angiogenesis and increased total microvascular area 1.8-fold (95% CI 0.2 to 3.5) and 2.8-fold (95% CI 1.4 to 4.3), respectively. At rest, perfusion was maintained at normal levels, but at stress, relative perfusion was increased 1.4-fold (95% CI 1.1 to 1.7) for AdVEGF-B 186 and 1.3-fold (95% CI 1.0 to 1.7) for AdVEGF-D ΔNΔC , without causing coronary steal effect in the control area. The therapy was well tolerated and did not lead to any significant changes in laboratory safety parameters. Both AdVEGF-B 186 and AdVEGF-D ΔNΔC gene transfers induced efficient angiogenesis in the myocardium resulting in an increased myocardial perfusion measured by PET. Importantly, local perfusion increase did not induce any coronary steal effect. As such, both treatments seem suitable new candidates for the induction of therapeutic angiogenesis for the treatment of refractory angina. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

Directory of Open Access Journals (Sweden)

Mohammad Eftekhari

2015-01-01

Full Text Available Objective(s: Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right–sided cancer. Methods: To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. Results: A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed and 36 patients with right-sided cancer (controls] were enrolled. Dose-volume histogram (DVH [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46. In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03 and anterolateral (17.1% versus 2.8%, P=0.049 walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS of>3 was observed in twelve cases (34.3%, while in five of the controls (13.9%,(Odds ratio=1.3. There was no significant difference between the groups regarding left ventricular ejection fraction. Conclusion: The risk of radiation induced myocardial

Spatial interaction between tissue pressure and skeletal muscle perfusion during contraction.

Science.gov (United States)

van Donkelaar, C C; Huyghe, J M; Vankan, W J; Drost, M R

2001-05-01

The vascular waterfall theory attributes decreased muscle perfusion during contraction to increased intramuscular pressure (P(IM)) and concomitant increase in venous resistance. Although P(IM) is distributed during contractions, this theory does not account for heterogeneity. This study hypothesises that pressure heterogeneity could affect the interaction between P(IM) rise and perfusion. Regional tissue perfusion during submaximum (100kPa) tetanic contraction is studied, using a finite element model of perfused contracting skeletal muscle. Capillary flow in muscles with one proximal artery and vein (SIM(1)) and with an additional distal artery and vein (SIM(2)) is compared. Blood flow and pressures at rest and P(IM) during contraction ( approximately 25kPa maximally) are similar between simulations, but capillary flow and venous pressure differ. In SIM(2), venous pressure and capillary flow correspond to P(IM) distribution, whereas capillary flow in SIM(1) is less than 10% of flow in SIM(2), in the muscle half without draining vein. This difference is caused by a high central P(IM), followed by central venous pressure rise, in agreement with the waterfall theory. The high central pressure (SIM(1)), obstructs outflow from the distal veins. Distal venous pressure rises until central blood pressure is reached, although local P(IM) is low. Adding a distal vein (SIM(2)) restores the perfusion. It is concluded that regional effects contribute to the interaction between P(IM) and perfusion during contraction. Unlike stated by the vascular waterfall theory, venous pressure may locally exceed P(IM). Although this can be explained by the principles of this theory, the theory does not include this phenomenon as such.

Statistical analysis of dose heterogeneity in circulating blood: Implications for sequential methods of total body irradiation

International Nuclear Information System (INIS)

Molloy, Janelle A.

2010-01-01

Purpose: Improvements in delivery techniques for total body irradiation (TBI) using Tomotherapy and intensity modulated radiation therapy have been proven feasible. Despite the promise of improved dose conformality, the application of these ''sequential'' techniques has been hampered by concerns over dose heterogeneity to circulating blood. The present study was conducted to provide quantitative evidence regarding the potential clinical impact of this heterogeneity. Methods: Blood perfusion was modeled analytically as possessing linear, sinusoidal motion in the craniocaudal dimension. The average perfusion period for human circulation was estimated to be approximately 78 s. Sequential treatment delivery was modeled as a Gaussian-shaped dose cloud with a 10 cm length that traversed a 183 cm patient length at a uniform speed. Total dose to circulating blood voxels was calculated via numerical integration and normalized to 2 Gy per fraction. Dose statistics and equivalent uniform dose (EUD) were calculated for relevant treatment times, radiobiological parameters, blood perfusion rates, and fractionation schemes. The model was then refined to account for random dispersion superimposed onto the underlying periodic blood flow. Finally, a fully stochastic model was developed using binomial and trinomial probability distributions. These models allowed for the analysis of nonlinear sequential treatment modalities and treatment designs that incorporate deliberate organ sparing. Results: The dose received by individual blood voxels exhibited asymmetric behavior that depended on the coherence among the blood velocity, circulation phase, and the spatiotemporal characteristics of the irradiation beam. Heterogeneity increased with the perfusion period and decreased with the treatment time. Notwithstanding, heterogeneity was less than ±10% for perfusion periods less than 150 s. The EUD was compromised for radiosensitive cells, long perfusion periods, and short treatment times

Statistical analysis of dose heterogeneity in circulating blood: implications for sequential methods of total body irradiation.

Science.gov (United States)

Molloy, Janelle A

2010-11-01

Improvements in delivery techniques for total body irradiation (TBI) using Tomotherapy and intensity modulated radiation therapy have been proven feasible. Despite the promise of improved dose conformality, the application of these "sequential" techniques has been hampered by concerns over dose heterogeneity to circulating blood. The present study was conducted to provide quantitative evidence regarding the potential clinical impact of this heterogeneity. Blood perfusion was modeled analytically as possessing linear, sinusoidal motion in the craniocaudal dimension. The average perfusion period for human circulation was estimated to be approximately 78 s. Sequential treatment delivery was modeled as a Gaussian-shaped dose cloud with a 10 cm length that traversed a 183 cm patient length at a uniform speed. Total dose to circulating blood voxels was calculated via numerical integration and normalized to 2 Gy per fraction. Dose statistics and equivalent uniform dose (EUD) were calculated for relevant treatment times, radiobiological parameters, blood perfusion rates, and fractionation schemes. The model was then refined to account for random dispersion superimposed onto the underlying periodic blood flow. Finally, a fully stochastic model was developed using binomial and trinomial probability distributions. These models allowed for the analysis of nonlinear sequential treatment modalities and treatment designs that incorporate deliberate organ sparing. The dose received by individual blood voxels exhibited asymmetric behavior that depended on the coherence among the blood velocity, circulation phase, and the spatiotemporal characteristics of the irradiation beam. Heterogeneity increased with the perfusion period and decreased with the treatment time. Notwithstanding, heterogeneity was less than +/- 10% for perfusion periods less than 150 s. The EUD was compromised for radiosensitive cells, long perfusion periods, and short treatment times. However, the EUD was

Microfluidic perfusion culture of human induced pluripotent stem cells under fully defined culture conditions.

Science.gov (United States)

Yoshimitsu, Ryosuke; Hattori, Koji; Sugiura, Shinji; Kondo, Yuki; Yamada, Rotaro; Tachikawa, Saoko; Satoh, Taku; Kurisaki, Akira; Ohnuma, Kiyoshi; Asashima, Makoto; Kanamori, Toshiyuki

2014-05-01

Human induced pluripotent stem cells (hiPSCs) are a promising cell source for drug screening. For this application, self-renewal or differentiation of the cells is required, and undefined factors in the culture conditions are not desirable. Microfluidic perfusion culture allows the production of small volume cultures with precisely controlled microenvironments, and is applicable to high-throughput cellular environment screening. Here, we developed a microfluidic perfusion culture system for hiPSCs that uses a microchamber array chip under defined extracellular matrix (ECM) and culture medium conditions. By screening various ECMs we determined that fibronectin and laminin are appropriate for microfluidic devices made out of the most popular material, polydimethylsiloxane (PDMS). We found that the growth rate of hiPSCs under pressure-driven perfusion culture conditions was higher than under static culture conditions in the microchamber array. We applied our new system to self-renewal and differentiation cultures of hiPSCs, and immunocytochemical analysis showed that the state of the hiPSCs was successfully controlled. The effects of three antitumor drugs on hiPSCs were comparable between microchamber array and 96-well plates. We believe that our system will be a platform technology for future large-scale screening of fully defined conditions for differentiation cultures on integrated microfluidic devices. © 2013 Wiley Periodicals, Inc.

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

Energy Technology Data Exchange (ETDEWEB)

Michallek, Florian; Dewey, Marc [Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Charite - Universitaetsmedizin Berlin, Medical School, Department of Radiology, Berlin (Germany)

2014-01-15

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

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

International Nuclear Information System (INIS)

Michallek, Florian; Dewey, Marc

2014-01-01

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

Phenotypic heterogeneity in a bacteriophage population only appears as stress-induced mutagenesis.

Science.gov (United States)

Yosef, Ido; Edgar, Rotem; Qimron, Udi

2016-11-01

Stress-induced mutagenesis has been studied in cancer cells, yeast, bacteria, and archaea, but not in viruses. In a recent publication, we present a bacteriophage model showing an apparent stress-induced mutagenesis. We show that the stress does not drive the mutagenesis, but only selects the fittest mutants. The mechanism underlying the observed phenomenon is a phenotypic heterogeneity that resembles persistence of the viral population. The new findings, the background for the ongoing debate on stress-induced mutagenesis, and the phenotypic heterogeneity underlying a novel phage infection strategy are discussed in this short manuscript.

Spatial interaction between tissue pressure and skeletal muscle perfusion during contraction

NARCIS (Netherlands)

Donkelaar, van C.C.; Huyghe, J.M.R.J.; Vankan, W.J.; Drost, M.R.

2001-01-01

The vascular waterfall theory attributes decreased muscle perfusion during contraction to increased intramuscular pressure (P_IM ) and concomitant increase in venous resistance. Although P_IM is distributed during contractions, this theory does not account for heterogeneity.This study hypothesises

Role of pressure in angiotensin II-induced renal injury: chronic servo-control of renal perfusion pressure in rats.

Science.gov (United States)

Mori, Takefumi; Cowley, Allen W

2004-04-01

Renal perfusion pressure was servo-controlled chronically in rats to quantify the relative contribution of elevated arterial pressure versus angiotensin II (Ang II) on the induction of renal injury in Ang II-induced hypertension. Sprague-Dawley rats fed a 4% salt diet were administered Ang II for 14 days (25 ng/kg per minute IV; saline only for sham rats), and the renal perfusion pressure to the left kidney was continuously servo-controlled to maintain a normal pressure in that kidney throughout the period of hypertension. An aortic occluder was implanted around the aorta between the two renal arteries and carotid and femoral arterial pressure were measured continuously throughout the experiment to determine uncontrolled and controlled renal perfusion pressure, respectively. Renal perfusion pressure of uncontrolled, controlled, and sham kidneys over the period of Ang II or saline infusion averaged 152.6+/-7.0, 117.4+/-3.5, and 110.7+/-2.2 mm Hg, respectively. The high-pressure uncontrolled kidneys exhibited tubular necrosis and interstitial fibrosis, especially prominent in the outer medullary region. Regional glomerular sclerosis and interlobular artery injury were also pronounced. Controlled kidneys were significantly protected from interlobular artery injury, juxtamedullary glomeruli injury, tubular necrosis, and interstitial fibrosis as determined by comparing the level of injury. Glomerular injury was not prevented in the outer cortex. Transforming growth factor (TGF)-beta and active NF-kappaB proteins determined by immunohistochemistry were colocalized in the uncontrolled kidney in regions of interstitial fibrosis. We conclude that the preferential juxtamedullary injury found in Ang II hypertension is largely induced by pressure and is probably mediated through the TGF-beta and NF-kappaB pathway.

Characteristic findings of exercise ECG test, perfusion SPECT and coronary angiography in patients with exercise induced myocardial stunning

Energy Technology Data Exchange (ETDEWEB)

Ahn, Byeong Cheol; Seo, Ji Hyoung; Bae, Jin Ho; Jeong, Shin Young; Park, Hun Sik; Lee, Jae Tae; Chae, Shung Chull; Lee, Kyu Bo [School of Medicine, Kyungpook National Univ., Daegu (Korea, Republic of)

2004-06-01

Transient wall motion abnormality and contractile dysfunction of the left ventricle (LV) can be observed in patients with coronary artery disease due to post-stress myocardial stunning. To understand clinical characteristics of stress induced LV dysfunction, we have compared the findings of exercise stress test, myocardial perfusion SPECT and coronary angiography between subjects with and without post-stress LV dysfunction. Among subjects who underwent exercise stress test, myocardial perfusion SPECT and coronary angiography within a month of interval, we enrolled 36 patients with post-stress LV ejection fraction (LVEF) was {>=}5% lower than rest (stunning group) and 16 patients with difference of post-stress and rest LVEF was lesser than 1% (non-stunning group) for this study. Treadmill exercise stress gated myocardial perfusion SPECT was performed with dual head SPECT camera using 740 MBq Tc-99m MIBI and coronary angiography was also performed by conventional Judkins method. Stunning group had a significantly higher incidence of hypercholesterolemia than non-stunning group(45.5 vs 7.1%, p=0.01). Stunning group also had higher incidence of diabetes mellitus and lower incidence of hypertension, but these were not statistically significant. Stunning group had larger and more severe perfusion defect in stress perfusion myocardial SPECT than non-stunning group(extent 18.2 vs 9.2%, p=0.029; severity 13.5 vs 6.9, p=0.040). Stunning group also had higher degree of reversibility of perfusion defect, higher incidence of positive exercise stress test and higher incidence of having severe stenosis(80{approx}99%) in coronary angiography than non-stunning group, but these were not statistically significant. In stunning group, all of 4 patients without perfusion defect had significant coronary artery stenosis and had received revascularization treatment. Patients with post-stress LV dysfunction had larger and more severe perfusion defect and severe coronary artery stenosis than

The incidence and functional consequences of RT-associated cardiac perfusion defects

International Nuclear Information System (INIS)

Marks, Lawrence B.; Yu Xiaoli; Prosnitz, Robert G.; Zhou Sumin; Hardenbergh, Patricia H.; Blazing, Michael; Hollis, Donna; Lind, Pehr; Tisch, Andrea; Wong, Terence Z.; Borges-Neto, Salvador

2005-01-01

Purpose: Radiation therapy (RT) for left-sided breast cancer has been associated with cardiac dysfunction. We herein assess the temporal nature and volume dependence of RT-induced left ventricular perfusion defects and whether these perfusion defects are related to changes in cardiac wall motion or alterations in ejection fraction. Methods: From 1998 to 2001, 114 patients were enrolled onto an IRB-approved prospective clinical study to assess changes in regional and global cardiac function after RT for left-sided breast cancer. Patients were imaged 30 to 60 minutes after injection of technetium 99m sestamibi or tetrofosmin. Post-RT perfusion scans were compared with the pre-RT studies to assess for RT-induced perfusion defects as well as functional changes in wall motion and ejection fraction. Two-tailed Fisher's exact test and the Cochran-Armitage test for linear trends were used for statistical analysis. Results: The incidence of new perfusion defects 6, 12, 18, and 24 months after RT was 27%, 29%, 38%, and 42%, respectively. New defects occurred in approximately 10% to 20% and 50% to 60% of patients with less than 5%, and greater than 5%, of their left ventricle included within the RT fields, respectively (p = 0.33 to 0.00008). The rates of wall motion abnormalities in patients with and without perfusion defects were 12% to 40% versus 0% to 9%, respectively; p values were 0.007 to 0.16, depending on the post-RT interval. Conclusions: Radiation therapy causes volume-dependent perfusion defects in approximately 40% of patients within 2 years of RT. These perfusion defects are associated with corresponding wall-motion abnormalities. Additional study is necessary to better define the long-term functional consequences of RT-induced perfusion defects

A Unifying model of perfusion and motion applied to reconstruction of sparsely sampled free-breathing myocardial perfusion MRI

DEFF Research Database (Denmark)

Pedersen, Henrik; Ólafsdóttir, Hildur; Larsen, Rasmus

2010-01-01

The clinical potential of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is currently limited by respiratory induced motion of the heart. This paper presents a unifying model of perfusion and motion in which respiratory motion becomes an integral part of myocardial perfusion...... quantification. Hence, the need for tedious manual motion correction prior to perfusion quantification is avoided. In addition, we demonstrate that the proposed framework facilitates the process of reconstructing DCEMRI from sparsely sampled data in the presence of respiratory motion. The paper focuses primarily...... on the underlying theory of the proposed framework, but shows in vivo results of respiratory motion correction and simulation results of reconstructing sparsely sampled data....

Prognostic implications of post-stress ejection fraction decrease detected by gated SPECT in the absence of stress-induced perfusion abnormalities

Energy Technology Data Exchange (ETDEWEB)

Dona, Manjola; Massi, Lucia; Settimo, Leonardo; Bartolini, Matteo; Gianni, Gianluca; Pupi, Alberto; Sciagra, Roberto [University of Florence, Nuclear Medicine Unit, Department of Clinical Physiopathology, Florence (Italy)

2011-03-15

The prognostic meaning of a post-stress ejection fraction (EF) decrease detected by perfusion gated SPECT is still unclear. We therefore followed up patients with post-stress EF decrease in the absence of stress-induced perfusion abnormalities. We prospectively enrolled 57 consecutive patients with post-stress EF drop {>=} 5 EF units and summed difference score (SDS) {<=} 1. They were followed up for more than 1 year and their outcome was compared with a group of sex- and age-matched controls with the same SDS but without EF decrease. During follow-up there were 13 events (1 cardiac death, 1 non-fatal myocardial infarction, 1 congestive heart failure and 10 late revascularizations). In the control group we registered six events. There was a significant difference (p < 0.0001) between the event-free survival curves of the two groups. The event rate of patients with post-stress EF decrease {>=} 5 EF units is relatively high and is significantly worse than that of a control group of patients with similarly normal SDS but without EF changes. Therefore, a post-stress EF decrease without stress-induced perfusion abnormalities should be cautiously interpreted. (orig.)

The Hepatoprotection Provided by Taurine and Glycine against Antineoplastic Drugs Induced Liver Injury in an Ex Vivo Model of Normothermic Recirculating Isolated Perfused Rat Liver

Directory of Open Access Journals (Sweden)

Reza Heidari

2016-03-01

Full Text Available Taurine (2-aminoethane sulfonic acid is a non-protein amino acid found in high concentration in different tissues. Glycine (Amino acetic acid is the simplest amino acid incorporated in the structure of proteins. Several investigations indicate the hepatoprotective properties of these amino acids. On the other hand, antineoplastic agents-induced serum transaminase elevation and liver injury is a clinical complication. The current investigation was designed to screen the possible hepatoprotective properties of taurine and glycine against antineoplastic drugs-induced hepatic injury in an ex vivo model of isolated perfused rat liver. Rat liver was perfused with different concentration (10 μM, 100 μM and 1000 μM of antineoplastic drugs (Mitoxantrone, Cyclophosphamide, Cisplatin, 5 Fluorouracil, Doxorubicin and Dacarbazine via portal vein. Taurine and glycine were administered to drug-treated livers and liver perfusate samples were collected for biochemical measurements (ALT, LDH, AST, and K+. Markers of oxidative stress (reactive oxygen species formation, lipid peroxidation, total antioxidant capacity and glutathione were also assessed in liver tissue. Antineoplastic drugs caused significant pathological changes in perfusate biochemistry. Furthermore, markers of oxidative stress were significantly elevated in drug treated livers. It was found that taurine (5 and 10 mM and glycine (5 and 10 mM administration significantly mitigated the biomarkers of liver injury and attenuated drug induced oxidative stress. Our data indicate that taurine and glycine supplementation might help as potential therapeutic options to encounter anticancer drugs-induced liver injury.

Assessment of perfusion pattern and extent of perfusion defect on dual-energy CT angiography: Correlation between the causes of pulmonary hypertension and vascular parameters

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Young [Dept. of Radiology, Chonbuk National University Medical School and Hospital, Research Institute of Clinical Medicine, Jeonju (Korea, Republic of); Seo, Joon Beom; Oh, Sang Young; Lee, Choong Wook; Lee, Sang Min [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Hwang, Hye Jeon [Dept. of Radiology, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Lee, Young Kyung [Dept. of Radiology, Seoul Medical Center, Seoul (Korea, Republic of)

2014-04-15

To assess perfusion patterns on a dual-energy pulmonary CT angiography (DECTA) of pulmonary hypertension (PHT) with variable causes and to assess whether the extent of perfusion defect can be used in the severity assessment of PHT. Between March 2007 and February 2011, DECTA scans of 62 consecutive patients (24 men, 38 women; mean age, 58.5 ± 17.3 [standard deviation] years; range, 19-87 years) with PHT were retrospectively included with following inclusion criteria; 1) absence of acute pulmonary thromboembolism, 2) maximal velocity of tricuspid regurgitation jet (TR Vmax) above 3 m/s on echocardiography performed within one week of the DECTA study. Perfusion patterns of iodine map were divided into normal (NL), diffuse heterogeneously decreased (DH), multifocal geographic and multiple peripheral wedging patterns. The extent of perfusion defects (PD), the diameter of main pulmonary artery (MPA) and the ratio of ascending aorta diameter/MPA (aortopulmonary ratio, APR) were measured. Pearson correlation analysis was performed between TR Vmax on echocardiography and CT imaging parameters. Common perfusion patterns of primary PHT were DH (n = 15) and NL (n = 12). The perfusion patterns of secondary PHT were variable. On the correlation analysis, in primary PHT, TR Vmax significantly correlated with PD, MPA and APR (r = 0.52, r = 0.40, r = -0.50, respectively, all p < 0.05). In secondary PHT, TR Vmax significantly correlated with PD and MPA (r = 0.38, r = 0.53, respectively, all p < 0.05). Different perfusion patterns are observed on DECTA of PHT according to the causes. PD and MPA are significantly correlated with the TR Vmax.

Assessment of perfusion pattern and extent of perfusion defect on dual-energy CT angiography: Correlation between the causes of pulmonary hypertension and vascular parameters

International Nuclear Information System (INIS)

Kim, Eun Young; Seo, Joon Beom; Oh, Sang Young; Lee, Choong Wook; Lee, Sang Min; Hwang, Hye Jeon; Lee, Young Kyung

2014-01-01

To assess perfusion patterns on a dual-energy pulmonary CT angiography (DECTA) of pulmonary hypertension (PHT) with variable causes and to assess whether the extent of perfusion defect can be used in the severity assessment of PHT. Between March 2007 and February 2011, DECTA scans of 62 consecutive patients (24 men, 38 women; mean age, 58.5 ± 17.3 [standard deviation] years; range, 19-87 years) with PHT were retrospectively included with following inclusion criteria; 1) absence of acute pulmonary thromboembolism, 2) maximal velocity of tricuspid regurgitation jet (TR Vmax) above 3 m/s on echocardiography performed within one week of the DECTA study. Perfusion patterns of iodine map were divided into normal (NL), diffuse heterogeneously decreased (DH), multifocal geographic and multiple peripheral wedging patterns. The extent of perfusion defects (PD), the diameter of main pulmonary artery (MPA) and the ratio of ascending aorta diameter/MPA (aortopulmonary ratio, APR) were measured. Pearson correlation analysis was performed between TR Vmax on echocardiography and CT imaging parameters. Common perfusion patterns of primary PHT were DH (n = 15) and NL (n = 12). The perfusion patterns of secondary PHT were variable. On the correlation analysis, in primary PHT, TR Vmax significantly correlated with PD, MPA and APR (r = 0.52, r = 0.40, r = -0.50, respectively, all p < 0.05). In secondary PHT, TR Vmax significantly correlated with PD and MPA (r = 0.38, r = 0.53, respectively, all p < 0.05). Different perfusion patterns are observed on DECTA of PHT according to the causes. PD and MPA are significantly correlated with the TR Vmax.

Quantifying seismic anisotropy induced by small-scale chemical heterogeneities

Science.gov (United States)

Alder, C.; Bodin, T.; Ricard, Y.; Capdeville, Y.; Debayle, E.; Montagner, J. P.

2017-12-01

Observations of seismic anisotropy are usually used as a proxy for lattice-preferred orientation (LPO) of anisotropic minerals in the Earth's mantle. In this way, seismic anisotropy observed in tomographic models provides important constraints on the geometry of mantle deformation associated with thermal convection and plate tectonics. However, in addition to LPO, small-scale heterogeneities that cannot be resolved by long-period seismic waves may also produce anisotropy. The observed (i.e. apparent) anisotropy is then a combination of an intrinsic and an extrinsic component. Assuming the Earth's mantle exhibits petrological inhomogeneities at all scales, tomographic models built from long-period seismic waves may thus display extrinsic anisotropy. In this paper, we investigate the relation between the amplitude of seismic heterogeneities and the level of induced S-wave radial anisotropy as seen by long-period seismic waves. We generate some simple 1-D and 2-D isotropic models that exhibit a power spectrum of heterogeneities as what is expected for the Earth's mantle, that is, varying as 1/k, with k the wavenumber of these heterogeneities. The 1-D toy models correspond to simple layered media. In the 2-D case, our models depict marble-cake patterns in which an anomaly in shear wave velocity has been advected within convective cells. The long-wavelength equivalents of these models are computed using upscaling relations that link properties of a rapidly varying elastic medium to properties of the effective, that is, apparent, medium as seen by long-period waves. The resulting homogenized media exhibit extrinsic anisotropy and represent what would be observed in tomography. In the 1-D case, we analytically show that the level of anisotropy increases with the square of the amplitude of heterogeneities. This relation is numerically verified for both 1-D and 2-D media. In addition, we predict that 10 per cent of chemical heterogeneities in 2-D marble-cake models can

Hepatic perfusion during hepatic artery infusion chemotherapy: Evaluation with perfusion CT and perfusion scintigraphy

International Nuclear Information System (INIS)

Miller, D.L.; Carrasquillo, J.A.; Lutz, R.J.; Chang, A.E.

1989-01-01

The standard method for the evaluation of hepatic perfusion during hepatic artery infusion (HAI) chemotherapy is planar hepatic artery perfusion scintigraphy (HAPS). Planar HAPS was performed with 2 mCi of [99mTc] macroaggregated albumin infused at 1 ml/min and compared with single photon emission CT (SPECT) HAPS and with a new study, CT performed during the slow injection of contrast material through the HAI catheter (HAI-CT). Thirteen patients underwent 16 HAI-CT studies, 14 planar HAPS studies, and 9 SPECT HAPS studies. In 13 of 14 studies (93%) HAI-CT and planar HAPS were in complete agreement as to the perfusion pattern of intrahepatic metastases and normal liver. In nine studies where all modalities were performed, the findings identified by HAI-CT and planar HAPS agreed in all cases, whereas the results of two SPECT scans disagreed with the other studies. With respect to perfusion of individual metastases, 14 of 14 HAI-CT studies, 12 of 13 planar HAPS studies, and 9 of 9 SPECT HAPS studies correctly demonstrated the perfusion status of individual lesions as indicated by the pattern of changes in tumor size determined on CT obtained before and after the perfusion studies. Hepatic artery infusion CT was superior for delineation of individual metastases, particularly small lesions, and for the evaluation of nonperfused portions of the liver. Planar HAPS detected extrahepatic perfusion in four patients, and this was not detected by HAI-CT. We conclude that HAI-CT and scintigraphy are complementary techniques. Hepatic artery infusion CT has advantages for the evaluation of intrahepatic perfusion, and planar HAPS is superior to HAI-CT for the detection of extrahepatic perfusion

Acute volume expansion attenuates hyperthermia-induced reductions in cerebral perfusion during simulated hemorrhage

DEFF Research Database (Denmark)

Schlader, Zachary J; Seifert, Thomas; Wilson, Thad E

2013-01-01

Hyperthermia reduces the capacity to withstand a simulated hemorrhagic challenge, but volume loading preserves this capacity. This study tested the hypotheses that acute volume expansion during hyperthermia increases cerebral perfusion and attenuates reductions in cerebral perfusion during...... infusion while hyperthermic. Primary dependent variables were mean middle cerebral artery blood velocity (MCAvmean), serving as an index of cerebral perfusion; mean arterial pressure (MAP); and cardiac output (thermodilution). During baseline, hyperthermia reduced MCAvmean (P = 0.001) by 12 ± 9% relative...

Heterogeneity in induced thermal resistance of rat tumor cell clones

International Nuclear Information System (INIS)

Tomasovic, S.P.; Rosenblatt, P.L.; Heitzman, D.

1983-01-01

Four 13762NF rat mammary adenocarcinoma clones were examined for their survival response to heating under conditions that induced transient thermal resistance (thermotolerance). Clones MTC and MTF7 were isolated from the subcutaneous locally growing tumor, whereas clones MTLn2 and MTLn3 were derived from spontaneous lung metastases. There was heterogeneity among these clones in thermotolerance induced by either fractionated 45 0 C or continuous 42 0 C heating, but the order of sensitivity was not necessarily the same. The clones developed thermal resistance at different rates and to different degrees within the same time intervals. There was heterogeneity between clones isolated from within either the primary site or metastatic lesions. However, clones derived from metastatic foci did not intrinsically acquire more or less thermotolerance to fractionated 45 0 C or continuous 42 0 C heating than did clones from the primary tumor. Further, there was no apparent relationship between any phenotypic properties that conferred more or less thermotolerance in vitro and any phenotypic properties that conferred enhanced metastatic success of these same clones by spontaneous (subcutaneous) or experimental (intravenous) routes in vivo. These tumor clones also differ in their karyotype, metastatic potential, cell surface features, sensitivity to x-irradiation and drugs, and ability to repair sublethal radiation damage. These results provide further credence to the concept that inherent heterogeneity within tumors may be as important in therapeutic success as other known modifiers of outcome such as site and treatment heterogeneity

Bacterial lipopolysaccharide-induced systemic inflammation alters perfusion of white matter-rich regions without altering flow in brain-irrigating arteries: Relationship to blood-brain barrier breakdown?

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Dhaya, Ibtihel; Griton, Marion; Raffard, Gérard; Amri, Mohamed; Hiba, Bassem; Konsman, Jan Pieter

2018-01-15

To better understand brain dysfunction during sepsis, cerebral arterial blood flow was assessed with Phase Contrast Magnetic Resonance Imaging, perfusion with Arterial Spin Labeling and structure with diffusion-weighted Magnetic Resonance Imaging in rats after intraperitoneal administration of bacterial lipopolysaccharides. Although cerebral arterial flow was not altered, perfusion of the corpus callosum region and diffusion parallel to its fibers were higher after lipopolysaccharide administration as compared to saline injection. In parallel, lipopolysaccharide induced perivascular immunoglobulin-immunoreactivity in white matter. These findings indicate that systemic inflammation can result in increased perfusion, blood-brain barrier breakdown and altered water diffusion in white matter. Copyright © 2017 Elsevier B.V. All rights reserved.

Thoracic epidural anesthesia attenuates hemorrhagic-induced splanchnic hypo-perfusion in post-resuscitation experimental hemorrhagic shock

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Amir S Madjid

2008-06-01

Full Text Available The purpose of present study was to assess the effects of thoracic epidural anesthesia on splanchnic perfusion, bacterial translocation and histopathologic changes in experimental hemorrhagic shock in short-tailed macaques (Macaca nemestrina. Sixteen Macaca nemestrinas were randomly assigned to one of two groups i.e. the lidocaine group (n = 8, receiving general anesthesia plus lidocaine thoracic epidural anesthesia; and the saline group (n = 8, receiving general anesthesia alone as control. Hemorrhagic shock was induced by withdrawing blood gradually to a mean arterial pressure (MAP of 40 mm Hg, and maintained for 60 minutes. Animals were then resuscitated with their own blood and ringer lactate solution (RL. After resuscitation, epidural lidocaine 2% was given in the lidocaine group and saline in the control group. Resuscitation that was performed after one hour hemorrhagic shock, with hemodynamic variables and urine output returned to normal, revealed there was no improvement of splanchnic perfusion. PgCO2, P(g-aCO2, and pHi remained in critical value and tended to deteriorate in the saline group. Contrast to saline group, splanchnic perfusion in lidocaine group tended to improve. This condition was supported by the finding of less bacterial translocation and better histopathologic changes in lidocaine thoracic epidural anesthesia group than in saline group. This study concludes that lidocaine thoracic epidural anesthesia attenuates splachnic hypoperfusion in post-resuscitation hemorrhagic shock in Macaca nemestrina. (Med J Indones 2008; 17: 73-81Keywords: thoracic epidural anesthesia, lidocaine, hemorrhagic shock, splanchnic hypoperfusion, bacterial translocation

Increased peripheral vascular disease risk progressively constrains perfusion adaptability in the skeletal muscle microcirculation

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Butcher, Joshua T.; Frisbee, Stephanie J.; Olfert, I. Mark; Chantler, Paul D.; Tabone, Lawrence E.; d'Audiffret, Alexandre C.; Shrader, Carl D.; Goodwill, Adam G.; Stapleton, Phoebe A.; Brooks, Steven D.; Brock, Robert W.; Lombard, Julian H.

2015-01-01

To determine the impact of progressive elevations in peripheral vascular disease (PVD) risk on microvascular function, we utilized eight rat models spanning “healthy” to “high PVD risk” and used a multiscale approach to interrogate microvascular function and outcomes: healthy: Sprague-Dawley rats (SDR) and lean Zucker rats (LZR); mild risk: SDR on high-salt diet (HSD) and SDR on high-fructose diet (HFD); moderate risk: reduced renal mass-hypertensive rats (RRM) and spontaneously hypertensive rats (SHR); high risk: obese Zucker rats (OZR) and Dahl salt-sensitive rats (DSS). Vascular reactivity and biochemical analyses demonstrated that even mild elevations in PVD risk severely attenuated nitric oxide (NO) bioavailability and caused progressive shifts in arachidonic acid metabolism, increasing thromboxane A2 levels. With the introduction of hypertension, arteriolar myogenic activation and adrenergic constriction were increased. However, while functional hyperemia and fatigue resistance of in situ skeletal muscle were not impacted with mild or moderate PVD risk, blood oxygen handling suggested an increasingly heterogeneous perfusion within resting and contracting skeletal muscle. Analysis of in situ networks demonstrated an increasingly stable and heterogeneous distribution of perfusion at arteriolar bifurcations with elevated PVD risk, a phenomenon that was manifested first in the distal microcirculation and evolved proximally with increasing risk. The increased perfusion distribution heterogeneity and loss of flexibility throughout the microvascular network, the result of the combined effects on NO bioavailability, arachidonic acid metabolism, myogenic activation, and adrenergic constriction, may represent the most accurate predictor of the skeletal muscle microvasculopathy and poor health outcomes associated with chronic elevations in PVD risk. PMID:26702145

Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

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

2014-08-01

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

Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model

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Yamamoto, Tokihiro, E-mail: toyamamoto@ucdavis.edu [Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, California 95817 (United States); Kent, Michael S.; Wisner, Erik R. [Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California 95616 (United States); Johnson, Lynelle R.; Stern, Joshua A. [Department of Medicine and Epidemiology, University of California Davis School of Veterinary Medicine, Davis, California 95616 (United States); Qi, Lihong [Department of Public Health Sciences, University of California Davis, Davis, California 95616 (United States); Fujita, Yukio [Department of Radiation Oncology, Tokai University, Isehara, Kanagawa 259-1193 (Japan); Boone, John M. [Department of Radiology, University of California Davis School of Medicine, Sacramento, California 95817 (United States)

2016-07-15

Purpose: Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Methods: Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those two CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t

Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model.

Science.gov (United States)

Yamamoto, Tokihiro; Kent, Michael S; Wisner, Erik R; Johnson, Lynelle R; Stern, Joshua A; Qi, Lihong; Fujita, Yukio; Boone, John M

2016-07-01

Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those two CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t-test. The mean TRE

Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model

International Nuclear Information System (INIS)

Yamamoto, Tokihiro; Kent, Michael S.; Wisner, Erik R.; Johnson, Lynelle R.; Stern, Joshua A.; Qi, Lihong; Fujita, Yukio; Boone, John M.

2016-01-01

Purpose: Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Methods: Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those two CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t

Renal perfusion scintiscan

Science.gov (United States)

... Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion Images Kidney anatomy Kidney - blood and urine flow Intravenous pyelogram References Rottenberg G, Andi AC. Renal ...

Neuropsychological Correlates of Brain Perfusion SPECT in Patients with Macrophagic Myofasciitis.

Directory of Open Access Journals (Sweden)

Axel Van Der Gucht

Full Text Available Patients with aluminum hydroxide adjuvant-induced macrophagic myofasciitis (MMF complain of arthromyalgias, chronic fatigue and cognitive deficits. This study aimed to characterize brain perfusion in these patients.Brain perfusion SPECT was performed in 76 consecutive patients (aged 49±10 y followed in the Garches-Necker-Mondor-Hendaye reference center for rare neuromuscular diseases. Images were acquired 30 min after intravenous injection of 925 MBq 99mTc-ethylcysteinate dimer (ECD at rest. All patients also underwent a comprehensive battery of neuropsychological tests, within 1.3±5.5 mo from SPECT. Statistical parametric maps (SPM12 were obtained for each test using linear regressions between each performance score and brain perfusion, with adjustment for age, sex, socio-cultural level and time delay between brain SPECT and neuropsychological testing.SPM analysis revealed positive correlation between neuropsychological scores (mostly exploring executive functions and brain perfusion in the posterior associative cortex, including cuneus/precuneus/occipital lingual areas, the periventricular white matter/corpus callosum, and the cerebellum, while negative correlation was found with amygdalo-hippocampal/entorhinal complexes. A positive correlation was also observed between brain perfusion and the posterior associative cortex when the time elapsed since last vaccine injection was investigated.Brain perfusion SPECT showed a pattern of cortical and subcortical changes in accordance with the MMF-associated cognitive disorder previously described. These results provide a neurobiological substrate for brain dysfunction in aluminum hydroxide adjuvant-induced MMF patients.

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

International Nuclear Information System (INIS)

Noel, Cory V.; Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh; Moffett, Brady

2017-01-01

Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

Energy Technology Data Exchange (ETDEWEB)

Noel, Cory V. [Baylor College of Medicine, Department of Pediatric Cardiology, Houston, TX (United States); Texas Children' s Hospital, Department of Pediatric Cardiology, Houston, TX (United States); Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Moffett, Brady [Texas Children' s Hospital, Department of Pharmacology, Houston, TX (United States)

2017-03-15

Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

Diagnostic performance of semi-quantitative and quantitative stress CMR perfusion analysis: a meta-analysis.

Science.gov (United States)

van Dijk, R; van Assen, M; Vliegenthart, R; de Bock, G H; van der Harst, P; Oudkerk, M

2017-11-27

analysis our results show similar diagnostic accuracy comparing anatomical (AUC 0.86(0.83-0.89)) and functional reference standards (AUC 0.88(0.84-0.90)). Only the per territory analysis sensitivity did not show significant heterogeneity. None of the groups showed signs of publication bias. The clinical value of semi-quantitative and quantitative CMR perfusion analysis remains uncertain due to extensive inter-study heterogeneity and large differences in CMR perfusion acquisition protocols, reference standards, and methods of assessment of myocardial perfusion parameters. For wide spread implementation, standardization of CMR perfusion techniques is essential. CRD42016040176 .

Radiation-induced increase in the release of amino acids by isolated, perfused skeletal muscle

International Nuclear Information System (INIS)

Schwenen, M.

1989-01-01

Local exposure of the hindquarter of the rat to 15Gy of gamma-radiation resulted, 4-6h after irradiation, in increased release of amino acids by the isolated, perfused hindquarter preparation, 70% of which is skeletal muscle. This increase in release involves not only alanine and glutamine, but also those amino acids not metabolized by muscle and, therefore, released in proportion to their occurrence in muscle proteins. Because metabolic parameters and content of energy-rich phosphate compounds in muscle remain unchanged, it is unlikely that general cellular damage is the underlying cause of the radiation-induced increase in amino acid release. The findings strongly favour the hypothesis that increased availability of amino acids results from enhanced protein break-down in skeletal muscle which has its onset shortly after irradiation. This radiation-induced disturbance in protein metabolism might be one of the pathogenetic factors in the aetiology of radiation myopathy. (author)

Simultaneous assessment of myocardial perfusion and function during mental stress in patients with chronic coronary artery disease.

Science.gov (United States)

Arrighi, James A; Burg, Matthew; Cohen, Ira S; Soufer, Robert

2003-01-01

Mental stress (MS) is an important provocateur of myocardial ischemia in many patients with chronic coronary artery disease. The majority of laboratory assessments of ischemia in response to MS have included measurements of either myocardial perfusion or function alone. We performed this study to determine the relationship between alterations in perfusion and ventricular function during MS. Methods and results Twenty-eight patients with reversible perfusion defects on exercise or pharmacologic stress myocardial perfusion imaging (MPI) underwent simultaneous technetium 99m sestamibi single photon emission computed tomography (SPECT) MPI and transthoracic echocardiography at rest and during MS according to a mental arithmetic protocol. In all cases the MS study was performed within 4 weeks of the initial exercise or pharmacologic MPI that demonstrated ischemia. SPECT studies were analyzed visually with the use of a 13-segment model and quantitatively by semiautomated circumferential profile analysis. Echocardiograms were graded on a segmental model for regional wall motion on a 4-point scale. Of 28 patients, 18 (64%) had perfusion defects and/or left ventricular dysfunction develop during MS: 9 (32%) had myocardial perfusion defects develop, 6 (21%) had regional or global left ventricular dysfunction develop, and 3 (11%) had both perfusion defects and left ventricular dysfunction develop. The overall concordance between perfusion and function criteria for ischemia during MS was only 46%. Among 9 patients with MS-induced left ventricular dysfunction, 5 had new regional wall motion abnormalities and 4 had a global decrement in function. In patients with MS-induced ischemia by SPECT, the number of reversible perfusion defects was similar during both MS and exercise/pharmacologic stress (2.8 +/- 2.0 vs 3.5 +/- 1.8, P =.41). Hemodynamic changes during MS were similar whether patients were divided on the basis of perfusion defects or left ventricular dysfunction during MS

CT of malignant choroidal melanoma - morphology and perfusion characteristics

International Nuclear Information System (INIS)

Heller, M.; Hagemann, J.; Jend, H.H.; Guthoff, R.

1982-01-01

The computed tomographic morphology of malignant choroidal melanoma and its perfusion characteristics are described. Thirty-three static and serial CT examinations made on 29 patients with choroidal melanoma, three with pseudotumors of the macula and one with choroidal metastasis revealed the choroidal melanoma to be usually a hyperdense, markedly perfused tumor, while the non-contrast, diagnostically undifferentiable pseudotumors and the choroidal metastasis, revealed no significant change in density after the administration of contrast material. Density values or perfusion characteristics of choroidal melanoma that are outside of the normal range are a result of secondary changes within the immediate surroundings of the tumor, such as detachment of the retina, tumor-induced glaucoma, or tumor necrosis. (orig.)

Role of myocardial perfusion SPECT in asymptomatic diabetic patients

International Nuclear Information System (INIS)

Cho, I.; Chun, K.; Won, K.; Lee, H.; Park, J.; Shin, D.; Kim, Y.; Shim, B.; Lee, J.

2002-01-01

Purpose: It is important that early diagnosis and treatment of coronary artery disease in diabetic patients, but there are few reports on the prevalence of stress-induced myocardial perfusion abnormalities and the rates of cardiac event in patients with type 2 diabetes. We evaluated the scan findings on gated myocardial perfusion SPECT in asymptomatic diabetic patients. Methods: We performed pharmacological stress test and gated perfusion SPECT in 69 diabetic patients without cardiovascular symptom (mean age: 65 year, male 31 and female 38). Patients underwent two-day imaging protocol and stress study was performed injection of Tc-99m MIBI during adenosine infusion. We followed up these patients by reviewing medical records. Results: Fifty-two of 69 patients (74.5%) showed normal scan findings and 17 patients (24.6%) showed reversible or fixed perfusion defects. Three of 52 patients with normal scan findings showed decreased LV ejection fraction and decreased wall motion. Twenty-three patients with normal scan findings were possible to follow up for more than 1yr (mean time: 18.3±3.3 mo.) and they all had no cardiac event. Three patients with reversible perfusion defects were performed coronary angioplasty. Conclusion: Myocardial perfusion SPECT is a noninvasive method and maybe useful in early diagnosis and predicting prognosis in diabetic patients

Hyperventilation, cerebral perfusion, and syncope

DEFF Research Database (Denmark)

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

2014-01-01

dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2...... the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced...... cardiac output brain perfusion becomes jeopardized. Whether, in patients with cardiovascular disease and/or defect, cerebral blood flow cerebral control HV-induced hypocapnia elicits cerebral hypoperfusion, leading to TLOC, remains to be established....

Activation of rho is involved in the mechanism of hydrogen-peroxide-induced lung edema in isolated perfused rabbit lung.

Science.gov (United States)

Chiba, Y; Ishii, Y; Kitamura, S; Sugiyama, Y

2001-09-01

Acute lung injury is attributed primarily to increased vascular permeability caused by reactive oxygen species derived from neutrophils, such as hydrogen peroxide (H2O2). Increased permeability is accompanied by the contraction and cytoskeleton reorganization of endothelial cells, resulting in intercellular gap formation. The Rho family of Ras-like GTPases is implicated in the regulation of the cytoskeleton and cell contraction. We examined the role of Rho in H2O2-induced pulmonary edema with the use of isolated perfused rabbit lungs. To our knowledge, this is the first study to examine the role of Rho in increased vascular permeability induced by H2O2 in perfused lungs. Vascular permeability was evaluated on the basis of the capillary filtration coefficient (Kfc, ml/min/cm H2O/100 g). We found that H2O2 (300 microM) increased lung weight, Kfc, and pulmonary capillary pressure. These effects of H2O2 were abolished by treatment with Y-27632 (50 microM), an inhibitor of the Rho effector p160 ROCK. In contrast, the muscular relaxant papaverine inhibited the H2O2-induced rise in pulmonary capillary pressure, but did not suppress the increases in lung weight and Kfc. These findings indicate that H2O2 causes pulmonary edema by elevating hydrostatic pressure and increasing vascular permeability. Y-27632 inhibited the formation of pulmonary edema by blocking both of these H2O2-induced effects. Our results suggest that Rho-related pathways have a part in the mechanism of H2O2-induced pulmonary edema. Copyright 2001 Academic Press.

Myocordial perfusion SPECT with dipyridamole stress test in cardiac syndrome X

International Nuclear Information System (INIS)

Czepczynski, R.; Smolarek, I.; Sowinski, J.; Rogacka, D.; Kazmierczak, M.; Wysocki, H.

2006-01-01

Cardiac syndrome X defines patients with typical anginal chest pain, a positive exercise ECG stress test and angiographically normal coronary arteries. Aim of this study was to evaluate the role of myocardial perfusion SPECT with dipyridamole stress in the diagnosis of cardiac syndrome X. Patients, methods: 68 patients with syndrome X aged 32 to 60 years were subjected to myocardial imaging using 99m Tc-MIBI according to the two-days protocol: at rest and after dipyridamole infusion. Semiquantitative evaluation of the images was based on the assessment of 99m Tc-MIBI uptake in 17 myocardial segments using a 5-points scale (0 point - normal uptake, 4 points - no uptake). Scores obtained in each segment were summed up, constituting the summed rest score (SRS) and summed stress score (SSS). Results: mean SRS was 7.9 ± 4.8 and mean SSS was 7.2 ± 4.4 (non-significant difference). Individual comparison of SRS and SSS values revealed three patterns of scintigraphic images: (1) in 25 patients (36.8%), a paradoxical improvement of perfusion at stress images was found, (2) in 23 patients (33.8%), the myocardial perfusion deteriorated after dipyridamole, (3) in 20 patients (29.4%), no significant change of the myocordial perfusion between rest and stress images occurred. Conclusions: in cardiac syndrome X, myocardial SPECT with dipyridamole stress shows different patterns of myocardial perfusion that reflects heterogeneity of this pathology. (orig.)

Flow-perfusion interferes with chondrogenic and hypertrophic matrix production by mesenchymal stem cells

NARCIS (Netherlands)

Kock, Linda M; Malda, Jos; Dhert, Wouter J A; Ito, Keita; Gawlitta, Debby

2014-01-01

Flow-perfusion is being promoted as a way to grow tissue-engineered cartilage in vitro. Yet, there is a concern that flow-perfusion may induce unwanted mechanical effects on chondrogenesis and terminal differentiation. Therefore, the aim of this study is to evaluate the effect of fluid flow on

Effects of Constant Flow vs. Constant Pressure Perfusion on Fluid Filtration in Severe Hypothermic Isolated Blood-Perfused Rat Lungs.

Science.gov (United States)

Halsøy, Kathrine; Kondratiev, Timofey; Tveita, Torkjel; Bjertnaes, Lars J

2016-01-01

Victims of severe accidental hypothermia are prone to fluid extravasation but rarely develop lung edema. We hypothesize that combined hypothermia-induced increase in pulmonary vascular resistance (PVR) and a concomitant fall in cardiac output protect the lungs against edema development. Our aim was to explore in hypothermic-isolated blood-perfused rat lungs whether perfusion at constant pressure influences fluid filtration differently from perfusion at constant flow. Isolated blood-perfused rat lungs were hanging freely in a weight transducer for measuring weight changes (ΔW). Fluid filtration coefficient (Kfc), was determined by transiently elevating left atrial pressure (Pla) by 5.8 mmHg two times each during normothermia (37°C) and during hypothermia (15°C). The lung preparations were randomized to two groups. One group was perfused with constant flow (Constant flow group) and the other group with constant pulmonary artery pressure (Constant PPA group). Microvascular pressure (Pmv) was determined before and during elevation of Pla (ΔPmv) by means of the double occlusion technique. Kfc was calculated with the formula Kfc = ΔW/ΔPmv/min. All Kfc values were normalized to predicted lung weight (P LW ), which was based on body weight (BW) according to the formula: P LW  = 0.0053 BW - 0.48 and presented as Kfc PLW in mg/min/mmHg/g. At cessation, bronchoalveolar lavage (BAL) fluid/perfusate protein concentration (B/P) ratio was determined photometrically. Data were analyzed with parametric or non-parametric tests as appropriate. p  Kfc PLW and B/P ratio increased significantly by more than 10-fold during hypothermia concerted by visible signs of edema in the trachea. Hemoglobin and hematocrit increased within the Constant flow group and between the groups at cessation of the experiments. In hypothermic rat lungs perfused at constant flow, fluid filtration coefficient per gram P LW and B/P ratio increased more than 10-fold concerted by increased

Perfusion directed 3D mineral formation within cell-laden hydrogels.

Science.gov (United States)

Sawyer, Stephen William; Shridhar, Shivkumar Vishnempet; Zhang, Kairui; Albrecht, Lucas; Filip, Alex; Horton, Jason; Soman, Pranav

2018-06-08

Despite the promise of stem cell engineering and the new advances in bioprinting technologies, one of the major challenges in the manufacturing of large scale bone tissue scaffolds is the inability to perfuse nutrients throughout thick constructs. Here, we report a scalable method to create thick, perfusable bone constructs using a combination of cell-laden hydrogels and a 3D printed sacrificial polymer. Osteoblast-like Saos-2 cells were encapsulated within a gelatin methacrylate (GelMA) hydrogel and 3D printed polyvinyl alcohol (PVA) pipes were used to create perfusable channels. A custom-built bioreactor was used to perfuse osteogenic media directly through the channels in order to induce mineral deposition which was subsequently quantified via microCT. Histological staining was used to verify mineral deposition around the perfused channels, while COMSOL modeling was used to simulate oxygen diffusion between adjacent channels. This information was used to design a scaled-up construct containing a 3D array of perfusable channels within cell-laden GelMA. Progressive matrix mineralization was observed by cells surrounding perfused channels as opposed to random mineral deposition in static constructs. MicroCT confirmed that there was a direct relationship between channel mineralization within perfused constructs and time within the bioreactor. Furthermore, the scalable method presented in this work serves as a model on how large-scale bone tissue replacement constructs could be made using commonly available 3D printers, sacrificial materials, and hydrogels. © 2018 IOP Publishing Ltd.

Development of regional cerebral sub-hypothermia with perfusion of hypothermic liquids

International Nuclear Information System (INIS)

Wang Peng; Ji Xunming

2007-01-01

The neuroprotection of induced hypothermia has been investigated intensively and confirmed in animal models and it has been used clinically in many fields since the finding of sub-hypothermia can also reduce cerebral injury. However the use of hypothermia in clinics is limited by the simultaneously induced systemic complications. Recently the sub-hypothermia induced by hypothermic regional arterial perfusion is proved to be the most effective method to reach the goal, including hypothermic normal saline with no influences on whole body temperature, cardiac rhythm and blood coagulation. According to the well development, fruitful achievement in the present status of this field, the authors are surely to have the inspiration for the further investigation and development of regional cerebral sub-hypothermia with perfusion of hypothermic liquids. (authors)

Assessment of anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema with breath-hold SPECT-CT fusion images

International Nuclear Information System (INIS)

Suga, Kazuyoshi; Kawakami, Yasuhiko; Iwanaga, Hideyuki; Hayashi, Noriko; Seto, Akiko; Matsunaga, Naofumi

2008-01-01

Anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema was assessed on deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. Subjects were 38 patients with pulmonary emphysema and 11 non-smoker controls, who successfully underwent DIBrH and non-BrH perfusion SPECT using a dual-headed SPECT system during the period between January 2004 and June 2006. DIBrH SPECT was three-dimensionally co-registered with DIBrH CT to comprehend the relationship between lung perfusion defects and CT low attenuation areas (LAA). By comparing the appearance of lung perfusion on DIBrH with non-BrH SPECT, the correlation with the rate constant for the alveolar-capillary transfer of carbon monoxide (DLCO/VA) was compared between perfusion abnormalities on these SPECTs and LAA on CT. DIBrH SPECT provided fairly uniform perfusion in controls, but significantly enhanced perfusion heterogeneity when compared with non-BrH SPECT in pulmonary emphysema patients (P<0.001). The reliable DIBrH SPECT-CT fusion images confirmed more extended perfusion defects than LAA on CT in majority (73%) of patients. Perfusion abnormalities on DIBrH SPECT were more closely correlated with DLCO/VA than LAA on CT (P<0.05). DIBrH SPECT identifies affected lungs with perfusion abnormality better than does non-BrH SPECT in pulmonary emphysema. DIBrH SPECT-CT fusion images are useful for more accurately localizing affected lungs than morphologic CT alone in this disease. (author)

Hypercapnic acidosis modulates inflammation, lung mechanics, and edema in the isolated perfused lung.

Science.gov (United States)

De Smet, Hilde R; Bersten, Andrew D; Barr, Heather A; Doyle, Ian R

2007-12-01

Low tidal volume (V(T)) ventilation strategies may be associated with permissive hypercapnia, which has been shown by ex vivo and in vivo studies to have protective effects. We hypothesized that hypercapnic acidosis may be synergistic with low V(T) ventilation; therefore, we studied the effects of hypercapnia and V(T) on unstimulated and lipopolysaccharide-stimulated isolated perfused lungs. Isolated perfused rat lungs were ventilated for 2 hours with low (7 mL/kg) or moderately high (20 mL/kg) V(T) and 5% or 20% CO(2), with lipopolysaccharide or saline added to the perfusate. Hypercapnia resulted in reduced pulmonary edema, lung stiffness, tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) in the lavage and perfusate. The moderately high V(T) did not cause lung injury but increased lavage IL-6 and perfusate IL-6 as well as TNF-alpha. Pulmonary edema and respiratory mechanics improved, possibly as a result of a stretch-induced increase in surfactant turnover. Lipopolysaccharide did not induce significant lung injury. We conclude that hypercapnia exerts a protective effect by modulating inflammation, lung mechanics, and edema. The moderately high V(T) used in this study stimulated inflammation but paradoxically improved edema and lung mechanics with an associated increase in surfactant release.

Synaptic heterogeneity and stimulus-induced modulation of depression in central synapses.

Science.gov (United States)

Hunter, J D; Milton, J G

2001-08-01

Short-term plasticity is a pervasive feature of synapses. Synapses exhibit many forms of plasticity operating over a range of time scales. We develop an optimization method that allows rapid characterization of synapses with multiple time scales of facilitation and depression. Investigation of paired neurons that are postsynaptic to the same identified interneuron in the buccal ganglion of Aplysia reveals that the responses of the two neurons differ in the magnitude of synaptic depression. Also, for single neurons, prolonged stimulation of the presynaptic neuron causes stimulus-induced increases in the early phase of synaptic depression. These observations can be described by a model that incorporates two availability factors, e.g., depletable vesicle pools or desensitizing receptor populations, with different time courses of recovery, and a single facilitation component. This model accurately predicts the responses to novel stimuli. The source of synaptic heterogeneity is identified with variations in the relative sizes of the two availability factors, and the stimulus-induced decrement in the early synaptic response is explained by a slowing of the recovery rate of one of the availability factors. The synaptic heterogeneity and stimulus-induced modifications in synaptic depression observed here emphasize that synaptic efficacy depends on both the individual properties of synapses and their past history.

Regional myocardial perfusion in patients with atherosclerotic coronary artery disease, at rest and during angina pectoris induced by tachycardia

International Nuclear Information System (INIS)

Maseri, A.; L'Abbate, A.; Pesola, A.; Michelassi, C.; Marzilli, M.; De Nes, M.

1977-01-01

We studied regional myocardial perfusion by scintigraphic computer-assisted analysis of initial distribution, washout rates, and residual activity of 133 Xe injected into the left coronary artery of four patients with normal arteriograms and 14 patients with coronary stenosis. At rest, residual activity in poststenotic regions was always greater than in control regions, but initial washout rates were not slower. During angina, following xenon injections, the amount of indicator distributed to the poststenotic regions was markedly reduced; the increase of the initial washout rates was smaller than in control regions relative to rest, and residual activity was higher. Initial washout rates did not differ as much as from those of normal myocardium because in severe ischemia too little indicator is deposited initially in these regions to produce a change of any magnitude. Indeed, when angina was induced immediately after the xenon injection, poststenotic washout rates became much slower during angina than at rest, a finding that implicates functional factors in impairing poststenotic myocardial perfusion during angina

Femoral perfusion after pulsed electromagnetic field stimulation in a steroid-induced osteonecrosis model.

Science.gov (United States)

Ikegami, Akira; Ueshima, Keiichiro; Saito, Masazumi; Ikoma, Kazuya; Fujioka, Mikihiro; Hayashi, Shigeki; Ishida, Masashi; Fujiwara, Hiroyoshi; Mazda, Osam; Kubo, Toshikazu

2015-07-01

This study was designed to evaluate femoral perfusion after pulsed electromagnetic field (PEMF) stimulation in a steroid-induced osteonecrosis rabbit model by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Steroid-induced osteonecrosis was produced by single intramuscular injection of methylprednisolone in 15 rabbits. Eight rabbits underwent PEMF stimulation (PEMF group) and seven did not (control group). DCE-MRI was performed before PEMF stimulation, immediately before steroid administration, and 1, 5, 10, and 14 days after steroid administration. Regions of interest were set in the bilateral proximal femora. Enhancement ratio (ER), initial slope (IS), and area under the curve (AUC) were analyzed. ER, IS, and AUC in the control group significantly decreased after steroid administration compared with before administration (P<0.05). In PEMF group, IS significantly decreased; however, ER and AUC showed no significant differences after steroid administration compared with before. ER and IS in PEMF group were higher than in control group until 10th day, and AUC was higher until 5th day after steroid administration (P<0.05). PEMF stimulation restrains the decrease in blood flow after steroid administration. © 2015 Wiley Periodicals, Inc.

Cell-swelling-induced taurine release from isolated perfused rat liver

NARCIS (Netherlands)

Brand, H. S.; Meijer, A. J.; Gustafson, L. A.; Jörning, G. G.; Leegwater, A. C.; Maas, M. A.; Chamuleau, R. A.

1994-01-01

Astrocytes and lymphocytes are able to release significant amounts of taurine during periods of hypotonicity to reduce the increase in cell volume. To investigate this mechanism in the liver, we studied the release of free amino acids from isolated perfused rat liver during hypotonicity. The

Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging

International Nuclear Information System (INIS)

Boll, Daniel T.; Lewin, Jonathan S.; Young, Philip; Gilkeson, Robert C.; Siwik, Ernest S.

2005-01-01

The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. (orig.)

Blood perfusion in osteomyelitis studied with [15O]water PET in a juvenile porcine model

DEFF Research Database (Denmark)

Jødal, Lars; Nielsen, Ole L; Afzelius, Pia

2017-01-01

and not quantitative. Quantitative assessment of perfusion could aid in the selection of therapy. A non-invasive, quantitative way to study perfusion is dynamic [15O]water positron emission tomography (PET). We aim to demonstrate that the method can be used for measuring perfusion in OM lesions and hypothesize...... that perfusion will be less elevated in OM lesions than in soft tissue (ST) infection. The study comprised 11 juvenile pigs with haematogenous osteomyelitis induced by injection of Staphylococcus aureus into the right femoral artery 1 week before scanning (in one pig, 2 weeks). The pigs were dynamically PET...

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

Energy Technology Data Exchange (ETDEWEB)

Su, Hui [Iowa State Univ., Ames, IA (United States)

2001-01-01

Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm₂ for 40-μm wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection.

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

International Nuclear Information System (INIS)

Hui Su

2001-01-01

Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm(sub 2) for 40-(micro)m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection

Lung perfusion and emphysema distribution affect the outcome of endobronchial valve therapy

Directory of Open Access Journals (Sweden)

Thomsen C

2016-06-01

Full Text Available Christian Thomsen,1 Dorothea Theilig,2 Dominik Herzog,1 Alexander Poellinger,2 Felix Doellinger,2 Nils Schreiter,3 Vera Schreiter,2 Dirk Schürmann,1 Bettina Temmesfeld-Wollbrueck,1 Stefan Hippenstiel,1 Norbert Suttorp,1 Ralf-Harto Hubner1 1Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, 2Institute of Radiology, 3Institute of Nuclear Medicine, Charité – Universitätsmedizin Berlin, Berlin, Germany Abstract: The exclusion of collateral ventilation (CV and other factors affect the clinical success of endoscopic lung volume reduction (ELVR. However, despite its benefits, the outcome of ELVR remains difficult to predict. We investigated whether clinical success could be predicted by emphysema distribution assessed by computed tomography scan and baseline perfusion assessed by perfusion scintigraphy. Data from 57 patients with no CV in the target lobe (TL were retrospectively analyzed after ELVR with valves. Pulmonary function tests (PFT, St George’s Respiratory Questionnaire (SGRQ, and 6-minute walk tests (6MWT were performed on patients at baseline. The sample was grouped into high and low levels at the median of TL perfusion, ipsilateral nontarget lobe (INL perfusion, and heterogeneity index (HI. These groups were analyzed for association with changes in outcome parameters from baseline to 3 months follow-up. Compared to baseline, patients showed significant improvements in PFT, SGRQ, and 6MWT (all P≤0.001. TL perfusion was not associated with changes in the outcome. High INL perfusion was significantly associated with increases in 6MWT (P=0.014, and high HI was associated with increases in forced expiratory volume in 1 second (FEV1, (P=0.012. Likewise, there were significant correlations for INL perfusion and improvement of 6MWT (r=0.35, P=0.03 and for HI and improvement in FEV1 (r=0.45, P=0.001. This study reveals new attributes that associate with positive outcomes for patient selection prior to ELVR

desensitisation and calcium-sensitivity in the isolated perfused rat ...

African Journals Online (AJOL)

Dr Olaleye

-induced desensitisation to noradrenaline were studied in the isolated perfused rat tail artery. Responses to the activators noradrenaline (NA). (3μM) and potassium chloride (KCl) (100mM) were obtained in Ca2+-buffered saline. Activators ...

Regional glucose utilization in infarcted and remote myocardium: its relation to coronary anatomy and perfusion.

Science.gov (United States)

Fragasso, G; Chierchia, S L; Landoni, C; Lucignani, G; Rossetti, E; Sciammarella, M; Vanoli, G E; Fazio, F

1998-07-01

We studied the relationship between coronary anatomy, perfusion and metabolism in myocardial segments exhibiting transient and persistent perfusion defects on stress/rest 99Tcm-MIBI single photon emission tomography in 35 patients (31 males, 4 females, mean age 56 +/- 7 years) with a previous myocardial infarction. Quantitative coronary angiography and assessment of myocardial perfusion reserve and glucose metabolism were performed within 1 week of one another. Perfusion was assessed by SPET after the intravenous injection of 740 MBq of 99Tcm-MIBI at rest and after exercise. Regional myocardial glucose metabolism was assessed by position emission tomography at rest (200 MBq of 18F-2-deoxyglucose, FDG) after an overnight fast with no glucose loading. All 35 patients exhibited persistent perfusion defects consistent with the clinically identified infarct site, and 27 (77%) also showed various degrees of within-infarct FDG uptake; 11 patients developed exercise-induced transient perfusion defects within, or in the vicinity of, 15 infarct segments and resting FDG uptake was present in 10 of these segments (67%). Five patients also showed exercise-induced transient perfusion defects in nine segments remote from the site of infarct: resting FDG uptake was present in six of these regions (67%). Finally, nine patients had increased glucose uptake in non-infarcted regions not showing transient perfusion defects upon exercise testing and perfused by coronary arteries with only minor irregularities. Our results confirm the presence of viable tissue in a large proportion of infarct sites. Moreover, FDG uptake can be seen in regions perfused by coronary arteries showing minor irregularities, not necessarily resulting in detectable transient perfusion defects on a MIBI stress scan. Since the clinical significance of such findings is not clear, further studies should be conducted to assess the long-term evolution of perfusion, function and metabolism in non

Electrical neuromodulation improves myocardial perfusion and ameliorates refractory angina pectoris in patients with syndrome X : fad or future?

NARCIS (Netherlands)

Jessurun, G; Hautvast, RWM; Tio, RA; DeJongste, M

2003-01-01

At present, there is no reliable antianginal drug therapy for patients with cardiac syndrome X. Therefore, the effect of electrical neuromodulation on refractory angina pectoris and myocardial perfusion in cardiac syndrome X was assessed. Eight patients (aged 55 +/- 7 years) with heterogeneous

Laser doppler perfusion imaging

International Nuclear Information System (INIS)

Waardell, K.

1992-01-01

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

Small regulatory RNA-induced growth rate heterogeneity of Bacillus subtilis.

Science.gov (United States)

Mars, Ruben A T; Nicolas, Pierre; Ciccolini, Mariano; Reilman, Ewoud; Reder, Alexander; Schaffer, Marc; Mäder, Ulrike; Völker, Uwe; van Dijl, Jan Maarten; Denham, Emma L

2015-03-01

Isogenic bacterial populations can consist of cells displaying heterogeneous physiological traits. Small regulatory RNAs (sRNAs) could affect this heterogeneity since they act by fine-tuning mRNA or protein levels to coordinate the appropriate cellular behavior. Here we show that the sRNA RnaC/S1022 from the Gram-positive bacterium Bacillus subtilis can suppress exponential growth by modulation of the transcriptional regulator AbrB. Specifically, the post-transcriptional abrB-RnaC/S1022 interaction allows B. subtilis to increase the cell-to-cell variation in AbrB protein levels, despite strong negative autoregulation of the abrB promoter. This behavior is consistent with existing mathematical models of sRNA action, thus suggesting that induction of protein expression noise could be a new general aspect of sRNA regulation. Importantly, we show that the sRNA-induced diversity in AbrB levels generates heterogeneity in growth rates during the exponential growth phase. Based on these findings, we hypothesize that the resulting subpopulations of fast- and slow-growing B. subtilis cells reflect a bet-hedging strategy for enhanced survival of unfavorable conditions.

Effects of perfusion pressure and insulin on (3H) cytochalasin B (CB) binding to control and diabetic rat hearts

International Nuclear Information System (INIS)

Pleta, M.; Chan, T.

1987-01-01

Using ( 3 H) CB, they attempted to quantitate the changes in the amount of glucose transporters in the plasma membrane (PM) and intracellular membranes (HSP) prepared from rat hearts perfused with insulin, under low and high pressure. Membranes isolated from non-perfused hearts showed a PM/HSP ratio of (0.593). Hearts perfused with low pressure showed a lower ratio of (0.474). Perfusion with insulin increased the ratio to (1.8), almost a 3-4 fold increase from low perfusion pressure. These data correlate with insulin effects in glucose transport and CB binding in the fat cells. High pressure perfusion increased the PM/HSP ratio by 1-2 fold. ( 3 H) 2-DG transport indicates a comparable increase in glucose uptake with high pressure, but with insulin only a 1.5 fold increase was observed. Initial data obtained from streptozotocin (STZ) injected diabetic rats indicate low CB binding in the PM fraction. Only insulin, but not high perfusion pressure increased PM/HSP ratio in the STZ-diabetic hearts. Their data imply that while both caused apparent translocation of glucose transporters, influences on cardiac glucose metabolism by work load are different. Furthermore, STZ induced diabetes affected only the high perfusion pressure-induced and not the insulin-stimulated change in CB binding

Irradiation-Dependent Effects on Tumor Perfusion and Endogenous and Exogenous Hypoxia Markers in an A549 Xenograft Model

International Nuclear Information System (INIS)

Fokas, Emmanouil; Haenze, Joerg; Kamlah, Florentine; Eul, Bastian G.; Lang, Nico; Keil, Boris; Heverhagen, Johannes T.; Engenhart-Cabillic, Rita; An Hanxiang; Rose, Frank

2010-01-01

Purpose: Hypoxia is a major determinant of tumor radiosensitivity, and microenvironmental changes in response to ionizing radiation (IR) are often heterogenous. We analyzed IR-dependent changes in hypoxia and perfusion in A549 human lung adenocarcinoma xenografts. Materials and Methods: Immunohistological analysis of two exogenously added chemical hypoxic markers, pimonidazole and CCI-103F, and of the endogenous marker Glut-1 was performed time dependently after IR. Tumor vessels and apoptosis were analyzed using CD31 and caspase-3 antibodies. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and fluorescent beads (Hoechst 33342) were used to monitor vascular perfusion. Results: CCI-103F signals measuring the fraction of hypoxic areas after IR were significantly decreased by approximately 50% when compared with pimonidazole signals, representing the fraction of hypoxic areas from the same tumors before IR. Interestingly, Glut-1 signals were significantly decreased at early time point (6.5 h) after IR returning to the initial levels at 30.5 h. Vascular density showed no difference between irradiated and control groups, whereas apoptosis was significantly induced at 10.5 h post-IR. DCE-MRI indicated increased perfusion 1 h post-IR. Conclusions: The discrepancy between the hypoxic fractions of CCI-103F and Glut-1 forces us to consider the possibility that both markers reflect different metabolic alterations of tumor microenvironment. The reliability of endogenous markers such as Glut-1 to measure reoxygenation in irradiated tumors needs further consideration. Monitoring tumor microvascular response to IR by DCE-MRI and measuring tumor volume alterations should be encouraged.

Intra-peritoneal administration of interleukin-1 beta induces impaired insulin release from the perfused rat pancreas

DEFF Research Database (Denmark)

Wogensen, L; Helqvist, S; Pociot, F

1990-01-01

Previous studies have demonstrated a stimulatory effect of interleukin-1 beta (IL-1 beta) on insulin and glucagon release from the perfused rat pancreas, accompanied by selective lysis of 20% of beta-cells as assessed by electronmicroscopy. However, we have not observed an inhibitory action of IL-1...... beta on insulin release from the perfused pancreas as shown for isolated islets. To test whether periodical exposure of the endocrine pancreas to circulating IL-1 beta in vivo affects insulin release from the intact perfused pancreas, rats were treated with daily intraperitoneal injections of 4...

Estimation of bone perfusion as a function of intramedullary pressure in sheep

International Nuclear Information System (INIS)

Rosenthal, M.S.; Lehner, C.E.; Pearson, D.W.; Kanikula, T.M.; Adler, G.G.; Venci, R.; Lanphier, E.H.; De Luca, P.M.

1985-01-01

It has been reported previously that following decompression (i.e. diving ascents) the intramedullary pressure (IMP) in bone can rise dramatically and possibly by the mechanism which can induce dysbaric osteonecrosis or the ''silent bends''. If the blood supply for the bone transverses the marrow compartment, than an increase in IMP could cause a temporary decrease in perfusion or hemostasis and hence ischemia leading to bone necrosis. To test this hypothesis, the authors measured the perfusion of bone in sheep as a function of IMP. The bone perfusion was estimated by measuring the perfusion-limited clearance of Ar-41 (Eγ=1293 keV, T/sub 1/2/=1.83 h) from the bone mineral matrix of sheep's tibia. The argon gas was formed in vivo by the fast neutron activation of Ca-44 to Ar-41 following the Ca-44(n,α) reaction. Clearance of Ar-41 was measured by time gated gamma-ray spectroscopy. These results indicate that an elevation of intramedullary pressure can decrease perfusion in bone and may cause bone necrosis

Magnetic resonance myocardial perfusion imaging-First experience at 3.0 T

Energy Technology Data Exchange (ETDEWEB)

Klumpp, B. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: bernhard.klumpp@med.uni-tuebingen.de; Hoevelborn, T. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: tobias.hoevelborn@gmx.de; Fenchel, M. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: michael.fenchel@med.uni-tuebingen.de; Stauder, N.I. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: norbert.stauder@stgag.ch; Kramer, U. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: ulrich.kramer@med.uni-tuebingen.de; May, A. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: andreas.may@med.uni-tuebingen.de; Gawaz, M.P. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: meinrad.gawaz@med.uni-tuebingen.de; Claussen, C.D. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: claus.claussen@med.uni-tuebingen.de; Miller, S. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: stephan.miller@med.uni-tuebingen.de

2009-01-15

Objective: MR myocardial perfusion imaging (MRMPI) is an established technique for the evaluation of the hemodynamical relevance of coronary artery disease. Perfusion imaging at 3.0 T provides certain advantages compared to 1.5 T. Aim of this study was to evaluate myocardial MR perfusion imaging at 3.0 T. Materials and methods: Twelve patients with stable Angina pectoris and known or suspected coronary artery disease were examined at 3.0 T. Myocardial perfusion was assessed using a saturation recovery gradient echo 2D sequence (TR 1.9 ms, TE 1.0 ms, FA 12 deg.) with 0.05 mmol Gd-DTPA per kg body weight at stress during injection of 140 {mu}g adenosine/kg body weight/min and at rest in short axis orientation. Perfusion analysis was based on a least square fit of the signal/time curve (peak signal intensity, slope). Perfusion series were assessed by two independent observers. Reference for the presence of relevant coronary artery stenoses was invasive coronary angiography. Two experienced observers evaluated the coronary angiograms in biplane projections for the presence and grade of stenoses. Results were compared with the MR perfusion analysis. Results: All MR examinations could be safely performed and yielded high image quality. In eight patients stress-induced hypoperfusion was detected (stenosis >70% in coronary angiography). In four patients myocardial hypoperfusion was ruled out (stenosis <70%). The myocardial perfusion reserve index was significantly reduced in hypoperfused myocardium with 1.9 {+-} 1.6 compared to 2.5 {+-} 1.6 in regularly perfused myocardium (p < 0.05). In coronary angiography, eight patients were found to suffer from coronary artery disease, whereas in four patients coronary artery disease was ruled out. Conclusion: Our initial results show that MRMPI at 3.0 T provides reliably high-image quality and diagnostic accuracy.

Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

International Nuclear Information System (INIS)

Kang, Do Young; Cha, Kwang Soo; Han, Seung Ho; Park, Tae Ho; Kim, Moo Hyun; Kim, Young Dae

2005-01-01

Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 ± 8.5%, range:3 ∼ 35%) and mild to moderate severity (-71 ± 42.7%, range:-217 ∼ -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome

Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

Energy Technology Data Exchange (ETDEWEB)

Kang, Do Young; Cha, Kwang Soo; Han, Seung Ho; Park, Tae Ho; Kim, Moo Hyun; Kim, Young Dae [Donga University College of Medicine, Busan (Korea, Republic of)

2005-02-15

Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 {+-} 8.5%, range:3 {approx} 35%) and mild to moderate severity (-71 {+-} 42.7%, range:-217 {approx} -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome.

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

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Su, Hui [Iowa State Univ., Ames, IA (United States)

2001-01-01

Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, the author introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, they demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm² for 40-μm wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection. In the second part of this dissertation, the author used laser-induced native fluorescence coupled with capillary electrophoresis (LINF-CE) and microscope imaging to study the single cell degranulation. On the basis of good temporal correlation with events observed through an optical microscope, they have identified individual peaks in the fluorescence electropherograms as serotonin released from the granular core on contact with the surrounding fluid.

First-pass perfusion disturbance of coronary artery stenosis: an experimental study using MR imaging with Gd-DTPA enhancement

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Chung, Kyung Il; Lee, Young Ju [Ajou Univ. College of Medicine, Seoul (Korea, Republic of); Lim, Tae Hwan [Ulsan Univ. College of Medicine, Ulsan (Korea, Republic of)] [and others

1997-11-01

In order to determine the value of first-pass MR imaging in the diagnosis of myocardial ischemia, first-pass perfusion abnormality of coronary artery stenosis was observed in MRI after gadopentate dimeglumine(GD-DTPA) enhancement. The left anterior descending(LAD) coronary arteries of six dogs were subjected to approximately 70% stenosis confirmed by coronary angiography. Half an hour after adenosine and {sup 99m}Tc-sestamibi infusion, Gd-DTPA(0.2mmol/kg) and methylene blue were administered and termination was induced with potassium chloride. SE T1-weighted and single-photon emission computed tomography(SPECT) images were subsequently obtained and the findings of perfusion defect compared with specimen stain. Three dimensionally reconstructed MR images were used to measure signal intensity(SI) of normal myocardium and perfusion defect from their sectional and total volume. Five of six dogs with LAD artey stenosis ranging from 66% to 73% displayed perfusion defect on MRI, SPECT, and specimen stain, but the remaining dog with stenosis of 58% showed no such defect. MRI showed the perfusion defect as distinct low SI, enabling the measurement of percentage perfusion defect(24.4{+-}5.4%), which increased inferiorly. SI of normal myocardium and perfusion defect decreased inferiorly; their difference indicated stenosis-induced perfusion loss according to section location. Volumetric SI of normal myocardium and perfusion defect were 3.42{+-}0.52 and 2.16{+-}0.45, respectively(p<0.05). Gd-DTPA enhanced MRI displayed first-pass perfusion abnormality of coronary artery stenosis as perfusion defect with distinct low SI; this enabled the measurement of its volume and SI changes according to section location, and thus indicated the value of first-pass MR imaging in the diagnosis of myocardial ischemia.

First-pass perfusion disturbance of coronary artery stenosis: an experimental study using MR imaging with Gd-DTPA enhancement

International Nuclear Information System (INIS)

Chung, Kyung Il; Lee, Young Ju; Lim, Tae Hwan

1997-01-01

In order to determine the value of first-pass MR imaging in the diagnosis of myocardial ischemia, first-pass perfusion abnormality of coronary artery stenosis was observed in MRI after gadopentate dimeglumine(GD-DTPA) enhancement. The left anterior descending(LAD) coronary arteries of six dogs were subjected to approximately 70% stenosis confirmed by coronary angiography. Half an hour after adenosine and 99m Tc-sestamibi infusion, Gd-DTPA(0.2mmol/kg) and methylene blue were administered and termination was induced with potassium chloride. SE T1-weighted and single-photon emission computed tomography(SPECT) images were subsequently obtained and the findings of perfusion defect compared with specimen stain. Three dimensionally reconstructed MR images were used to measure signal intensity(SI) of normal myocardium and perfusion defect from their sectional and total volume. Five of six dogs with LAD artey stenosis ranging from 66% to 73% displayed perfusion defect on MRI, SPECT, and specimen stain, but the remaining dog with stenosis of 58% showed no such defect. MRI showed the perfusion defect as distinct low SI, enabling the measurement of percentage perfusion defect(24.4±5.4%), which increased inferiorly. SI of normal myocardium and perfusion defect decreased inferiorly; their difference indicated stenosis-induced perfusion loss according to section location. Volumetric SI of normal myocardium and perfusion defect were 3.42±0.52 and 2.16±0.45, respectively(p<0.05). Gd-DTPA enhanced MRI displayed first-pass perfusion abnormality of coronary artery stenosis as perfusion defect with distinct low SI; this enabled the measurement of its volume and SI changes according to section location, and thus indicated the value of first-pass MR imaging in the diagnosis of myocardial ischemia

Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

DEFF Research Database (Denmark)

Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas

2016-01-01

INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... perfusion with normothermic oxygenated blood during cardiopulmonary bypass appears to improve postoperative oxygenation in patients with COPD undergoing cardiac surgery. Pulmonary artery perfusion with hypothermic HTK solution does not seem to improve postoperative oxygenation. TRIAL REGISTRATION NUMBER...

Laser Doppler line scanner for monitoring skin perfusion changes of port wine stains during vascular-targeted photodynamic therapy

Science.gov (United States)

Chen, Defu; Ren, Jie; Wang, Ying; Gu, Ying

2014-11-01

Vascular-targeted photodynamic therapy (V-PDT) is known to be an effective therapeutic modality for the treatment of port wine stains (PWS). Monitoring the PWS microvascular response to the V-PDT is crucial for improving the effectiveness of PWS treatment. The objective of this study was to use laser Doppler technique to directly assess the skin perfusion in PWS before and during V-PDT. In this study, 30 patients with PWS were treated with V-PDT. A commercially laser Doppler line scanner (LDLS) was used to record the skin perfusion of PWS immediately before; and at 1, 3, 5, 7, 10, 15 and 20 minutes during V-PDT treatment. Our results showed that there was substantial inter- and intra-patient perfusion heterogeneity in PWS lesion. Before V-PDT, the comparison of skin perfusion in PWS and contralateral healthy control normal skin indicated that PWS skin perfusion could be larger than, or occasionally equivalent to, that of control normal skin. During V-PDT, the skin perfusion in PWS significantly increased after the initiation of V-PDT treatment, then reached a peak within 10 minutes, followed by a slowly decrease to a relatively lower level. Furthermore, the time for reaching peak and the subsequent magnitude of decrease in skin perfusion varied with different patients, as well as different PWS lesion locations. In conclusion, the LDLS system is capable of assessing skin perfusion changes in PWS during V-PDT, and has potential for elucidating the mechanisms of PWS microvascular response to V-PDT.

Reverse ventilation--perfusion mismatch

International Nuclear Information System (INIS)

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

1984-01-01

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

Sildenafil improves blood perfusion in steroid-induced avascular necrosis of femoral head in rabbits via a protein kinase G-dependent mechanism.

Science.gov (United States)

Song, Qichun; Ni, Jianlong; Jiang, Hongyuan; Shi, Zhibin

2017-10-01

The aim of the study were to evaluate the effect of sildenafil against avascular necrosis of femoral head (ANFH) in a rabbit model, and to study the role of protein kinase G (PKG) pathway and vascular endothelial growth factor (VEGF) in ANFH. Three weeks after inducing ANFH with methylprednisolone injection, 45 female adult New Zealand white rabbits were divided into three groups and treated as follows: group SI received daily intraperitoneal sildenafil with a dose of 10 mg/kg per day; group SD received daily sildenafil identically to group SI plus auricular vein injection DT3 (a specific PKG inhibitor); group NS received only normal saline. The blood perfusion function in the femoral head was measured by perfusion MRI and ink artery infusion. Bilateral femora heads were examined histopathologically for the presence of osteonecrosis; VEGF of tissue was examined by Western blot analysis; cGMP level and PKG activity were also measured. The incidence of ANFH in SI group was significantly lower than that observed in NS and SD groups (p < 0.05). VEGF in SI group was increased compared to NS group. cGMP level and PKG activity were also significantly different between NS and SI group (p < 0.05). However, these effects of sildenafil in SD group were all markedly inhibited by the administration of DT3 compared to SI group. Sildenafil appear to increase the perfusion of femoral head by up-regulating VEGF through PKG pathway. The increased perfusion of femoral head could prevent ANFH. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Note: A micro-perfusion system for use during real-time physiological studies under high pressure

Science.gov (United States)

Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

2014-10-01

We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

Comparison of Dextran Perfusion and GSI-B4 Isolectin Staining in a Mouse Model of Oxygen-induced Retinopathy.

Science.gov (United States)

Huang, Shaofen; Liang, Jiajian; Yam, Gary Hin-Fai; Lu, Zhihao; Pang, Chi Pui; Chen, Haoyu

2015-06-01

Oxygen-induced retinopathy (OIR) is a robust and widely used animal model for the study of retinal neovascularization (NV). Dextran perfusion and Griffonia simplicifolia isolectin B4 (GSI-B4) staining are two common methods for examining the occurrence and extent of OIR. This study provides a quantitative comparison of the two for OIR detection. At postnatal day 7 (PN7), fifteen C57BL/6J mice were exposed to a 75% hyperoxic condition for 5 days and then returned to room air conditions. At PN17, the mice received intravitreal injection of GSI-B4 Alexa Fluor 568 conjugate. After 10 hours, they were infused with FITC-dextran conjugate via the left ventricle. Retinal flat mounts were photographed by confocal microscopy. Areas with fluorescent signals and the total retinal areas were quantified by Image J software. Both GSI-B4 and dextran detected the peripheral neovascular area. The mean hyper fluorescence area was 0.33 ± 0.14% of whole retinal area determined by GSI-B4 staining and 0.25 ± 0.28% determined by dextran perfusion. The difference between the two measures was 0.08% (95% CI:-0.59%, 0.43%). The Pearson correlation coefficient between the two methods was 0.386,P =0.035. The mean coincidence rates were 14.3 ± 13.4% and 24.9 ± 18.5% for GSI-B4 and dextran staining, respectively. Both methods can complement each other in demonstrating and quantitatively evaluating retinal NV. A poor agreement was found between the two methods; GSI-B4 isolectin was more effective than FITC-dextran perfusion in evaluating the extent of retinal NV in a mouse model of OIR.

Perfusion dyssynchrony analysis

NARCIS (Netherlands)

Chiribiri, A.; Villa, A.D.M.; Sammut, E.; Breeuwer, M.; Nagel, E.

2015-01-01

AIMS: We sought to describe perfusion dyssynchrony analysis specifically to exploit the high temporal resolution of stress perfusion CMR. This novel approach detects differences in the temporal distribution of the wash-in of contrast agent across the left ventricular wall. METHODS AND RESULTS:

Brain perfusion: computed tomography applications

International Nuclear Information System (INIS)

Miles, K.A.

2004-01-01

Within recent years, the broad introduction of fast multi-detector computed tomography (CT) systems and the availability of commercial software for perfusion analysis have made cerebral perfusion imaging with CT a practical technique for the clinical environment. The technique is widely available at low cost, accurate and easy to perform. Perfusion CT is particularly applicable to those clinical circumstances where patients already undergo CT for other reasons, including stroke, head injury, subarachnoid haemorrhage and radiotherapy planning. Future technical developments in multi-slice CT systems may diminish the current limitations of limited spatial coverage and radiation burden. CT perfusion imaging on combined PET-CT systems offers new opportunities to improve the evaluation of patients with cerebral ischaemia or tumours by demonstrating the relationship between cerebral blood flow and metabolism. Yet CT is often not perceived as a technique for imaging cerebral perfusion. This article reviews the use of CT for imaging cerebral perfusion, highlighting its advantages and disadvantages and draws comparisons between perfusion CT and magnetic resonance imaging. (orig.)

Effect of Garlic on Perfusion Scintigraphy of Rabbit's Lungs ...

African Journals Online (AJOL)

Purpose: To study of the effect of garlic on rabbit's lungs, with the aid of perfusion scintigraphy, after experimentally-induced pulmonary embolism. Methods: Twelve adult rabbits were anesthetized. Prepared macroaggregated albumin- technetium 99m (99mTc-MAA) radiopharmaceutical was injected into the ear vein at a ...

3D power Doppler ultrasound assessment of placental perfusion during uterine contraction in labor.

Science.gov (United States)

Sato, Miki; Noguchi, Junko; Mashima, Masato; Tanaka, Hirokazu; Hata, Toshiyuki

2016-09-01

To assess placental perfusion during spontaneous or induced uterine contraction in labor at term using placental vascular sonobiopsy (PVS) by 3D power Doppler ultrasound with the VOCAL imaging analysis program. PVS was performed in 50 normal pregnancies (32 in spontaneous labor group [SLG], and 18 in induced labor group with oxytocin or prostaglandin F2α [ILG]) at 37-41 weeks of gestation to assess placental perfusion during uterine contraction in labor. Only pregnancies with an entirely visualized anterior placenta were included in the study. Data acquisition was performed before, during (at the peak of contraction), and after uterine contraction. 3D power Doppler indices such as the vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were calculated in each placenta. There were no abnormal fetal heart rate tracings during contraction in either group. VI and VFI values were significantly reduced during uterine contraction in both groups (SLG, -33.4% [-97.0-15.2%], and ILG, -49.6% [-78.2--4.0%]), respectively (P power Doppler indices (VI, FI, and VFI) during uterine contraction (at the peak of contraction) showed a correlation greater than 0.7, with good intra- and inter-observer agreements. Our findings suggest that uterine contraction in both spontaneous and induced labors causes a significant reduction in placental perfusion. Reduced placental blood flow in induced uterine contraction has a tendency to be marked compared with that in spontaneous uterine contraction. To the best of our knowledge, this is the first study on the non-invasive assessment of placental perfusion during uterine contraction in labor using 3D power Doppler ultrasound. However, the data and their interpretation in the present study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size are needed to assess placental perfusion and vascularity using PVS during normal and

Changes in perfusion and fatty acid metabolism of rat heart with autoimmune myocarditis

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, Eiichiro; Kusuoka, Hideo; Fukuchi, Kazuki; Hasegawa, Shinji; Yutani, Kenji; Nishimura, Tsunehiko [Osaka Univ., Suita (Japan). Biomedical Research Center; Hori, Masatsugu; Hirono, Satoru; Izumi, Tohru

2000-10-01

To elucidate the change in perfusion and aerobic metabolism in myocarditis, tissue counting and dual tracer ex vivo autoradiography with Tl-201 and free fatty acid analog, I-123- or I-125-labeled (p-iodophenyl)-methyl-pentadecanoic acid (BMIPP), were performed in rats with myocarditis induced by immunization with cardiac myosin. Inflammatory damage was classified histologically. At the acute stage (2-4 weeks after the antigen-injection), total heart uptakes of Tl and BMIPP and the ratio (BMIPP/Tl) were significantly reduced in myocarditis rats (N=15) compared with the controls (N=12). Myocardial distribution of Tl and BMIPP was not homogeneous. Relative uptake of Tl and BMIPP (N=9, 128 regions) was gradually decreased with the extent of inflammation, and the regional BMIPP/Tl was smaller than the control. At the subacute stage (7 weeks after the antigen-injection), total Tl uptake in myocarditis rats (N=5) recovered to the control level (N=4), but that of BMIPP was still significantly lower than the control. BMIPP/Tl was still significantly lower in myocarditis. Myocardial distribution of Tl and BMIPP recovered to be more homogeneous. Relative uptake of Tl and BMIPP (N=6, 78 regions) still gradually but significantly decreased with the extent of inflammation. Regional BMIPP/Tl was still depressed in myocarditis. These results indicate that myocardial perfusion and aerobic metabolism were discrepant and heterogeneously suppressed with severe inflammation during the acute stages, but the difference decreases with time. Examination with Tl-201 and BMIPP may provide information about the severity of myocarditis. (author)

Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

International Nuclear Information System (INIS)

Joo, Eun Yeon; Hong, Seung Bong; Tae, Woo Suk; Kim, Jee Hyun; Han, Sun Jung; Seo, Dae Won; Lee, Kyung-Han; Kim, Byung Tae; Kim, Myoung-Hee; Kim, Seunghwan; Lee, Mann Hyung

2005-01-01

Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion 99m Tc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion 99m Tc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC. (orig.)

Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

Energy Technology Data Exchange (ETDEWEB)

Joo, Eun Yeon; Hong, Seung Bong; Tae, Woo Suk; Kim, Jee Hyun; Han, Sun Jung; Seo, Dae Won [Sungkyunkwan University School of Medicine, Department of Neurology, Samsung Medical Center and Center for Clinical Medicine, SBRI, Seoul (Korea); Lee, Kyung-Han; Kim, Byung Tae [Sungkyunkwan University School of Medicine, Department of Nuclear Medicine, Samsung Medical Center and Center for Clinical Medicine, SBRI, Seoul (Korea); Kim, Myoung-Hee [Ewha Women' s University, Department of Computer Science and Engineering, Seoul (Korea); Kim, Seunghwan [POSTECH, APCTP/NCSL, Department of Physics, Pohang (Korea); Lee, Mann Hyung [Catholic University of Daegue, College of Pharmacy, Gyongbook (Korea)

2005-10-01

Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion {sup 99m}Tc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion {sup 99m}Tc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC. (orig.)

Non-invasive monitoring of muscle blood perfusion by photoplethysmography: evaluation of a new application.

Science.gov (United States)

Sandberg, M; Zhang, Q; Styf, J; Gerdle, B; Lindberg, L-G

2005-04-01

To evaluate a specially developed photoplethysmographic (PPG) technique, using green and near-infrared light sources, for simultaneous non-invasive monitoring of skin and muscle perfusion. Evaluation was based on assessments of changes in blood perfusion to various provocations, such as post-exercise hyperaemia and hyperaemia following the application of liniment. The deep penetrating feature of PPG was investigated by measurement of optical radiation inside the muscle. Simultaneous measurements using ultrasound Doppler and the new PPG application were performed to elucidate differences between the two methods. Specific problems related to the influence of skin temperature on blood flow were highlightened, as well. Following static and dynamic contractions an immediate increase in muscle perfusion was shown, without increase in skin perfusion. Liniment application to the skin induced a rapid increase in skin perfusion, but not in muscle. Both similarities and differences in blood flow measured by Ultrasound Doppler and PPG were demonstrated. The radiant power measured inside the muscle, by use of an optical fibre, showed that the near-infrared light penetrates down to the vascular depth inside the muscle. The results of this study indicate the potentiality of the method for non-invasive measurement of local muscle perfusion, although some considerations still have to be accounted for, such as influence of temperature on blood perfusion.

A capillary-based perfusion phantom for simulation of brain perfusion for MRI

International Nuclear Information System (INIS)

Maciak, A.; Kronfeld, A.; Mueller-Forell, W.; Wille, C.; Kempski, O.; Stoeter, P.

2010-01-01

Purpose: The measurement of the CBF is a non-standardized procedure and there are no reliable gold standards. This abstract shows a capillary-based perfusion-phantom for CE-DSC-MRI. It has equivalent flow properties to those within the tissue capillary system of the human brain and allows the validation of the Siemens Perfusion (MR) software. Materials and Methods: The perfusion phantom consists of a dialyzer for the simulation of the capillary system, a feeding tube for simulation of the AIF and a pulsatile pump for simulation of the heart. Using this perfusion phantom, the exact determination of the gold standard CBF due to the well-known geometry of the phantom is easy. It was validated based on different perfusion measurements. These measurements were investigated with standard software (Siemens Perfusion MR). The software determined the CBF within the capillary system. Based on this CBF, a comparison to the gold standard was made with several different flow speeds. After AIF selection, a total of 726 CBF data points were automatically extracted by the software. Results: This results in a comparison of the gold standard CBF to these 726 CBF values. Therefore, a reproducible and reliable deviation estimation between gold standard CBF and measured CBF using the software was computed. It can be shown that the deviation between gold standard and software-based evaluation ranges between 1 and 31 %. Conclusion: There is no significance for any correlation between flow speed and amount of deviation. The mean measured CBF is 11.4 % higher than the gold standard CBF (p-value < 0.001). Using this kind of perfusion-phantom, the validation of different software systems allows reliable conclusions about their quality. (orig.)

In vivo tomographic study of cerebral blood perfusion with SPECT in hemiparkinsonian monkeys

International Nuclear Information System (INIS)

Chen Shengdi; Xu Delong

1994-01-01

The authors present data on the utility of functional brain imaging with 99m Tc-ECD and SPECT in the study of MPTP induced hemiparkinsonism in monkeys. Injection of MPTP into the right common carotid artery of 10 rhesus monkeys produced hemiparkinsonism in the contralateral limbs which responded to antiparkinsonian medication. The unilateral neurotoxicity of the MPTP treated side was confirmed biochemically by marked reduction of DA contents in the nigrostriatum and histologically by selective neuronal loss in the substantia nigra. These monkeys with hemiparkinsonism were studied with SPECT using 99m Tc-ECD as perfusion marker. The results of brain scanning showed that the cerebral blood perfusion of MPTP treated side was significantly depleted 20∼90 days after MPTP intoxication, and returned to normal 8 months after perfusion. The experiment indicates that abnormal cerebral blood perfusion is involved in the course of parkinsonian pathophysiology

Perfusion CT in acute stroke

International Nuclear Information System (INIS)

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

2015-01-01

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

Myocardial perfusion abnormality and chest pain in patients with hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa

1991-01-01

To investigate the role of myocardial ischemia in the development of chest pain in patients with hypertrophic cardiomyopathy (HCM), exercise stress (Ex) redistribution myocardial single photon emission CT's (SPECT's) with thallium-201 (Tl) were obtained in 27 patients with HCM. In all patients, coronary arteries were normal arteriographically. Patients were classified into NYHA Class I, II and III according to the frequency and severity of the chest pain during daily life. In these 3 groups, age, sex and intraventricular septal thickness measured by echocardiography were not different. Types of myocardial perfusion obtained by myocardial SPECT's were divided into 5: (1) normal perfusion, (2) no perfusion defect with abnormal myocardial Tl washout rate (WOR) during 3 hours (<30%) [Def(-)/WORabn], (3) reversible perfusion defect (RD), (4) fixed defect with abnormal WOR (FD/WORabn), and (5) fixed defect with normal WOR (FD/WORnl). In 14 patients of Class I, 9 patients (64%) showed normal perfusion but the rest showed perfusion abnormality (def(-)/WORabn in 3 and RD in 2). In Class II and III, all patients showed perfusion abnormalities of RD, FD/WORabn or FD/WORnl. As the functional class progressed from Class II to III, the ratio of fixed defect (both WORnl and WORabn) to RD increased, but it was not statistically significant. In 2 patients in whom Ex SPECT's were repeated because of the progression of the chest pain, the severity of the perfusion abnormality also progressed. Perfusion abnormalities were observed most frequently in anterior (35%), then inferior/posterior (20%) and septal wall (18%). The frequency of Ex induced ECG abnormalities (ST-depression or T wave changes) increased as the NYHA Class progressed (Class III vs I p<0.05). These findings suggested the following: chest pain in patients with HCM relates to the myocardial ischemia which may originate in the myocardial small arteries, and when the lesions progress myocardial necrosis may ensue. (author)

Inter-chromosomal heterogeneity in the formation of radiation induced chromosomal aberrations

International Nuclear Information System (INIS)

Natarajan, A.T.; Vermeulen, S.; Boei, J.J.W.A.

1997-01-01

It is generally assumed that radiation induced chromosomal lesions are distributed randomly and repaired randomly among the genome. Recent studies using fluorescent in situ hybridization (FISH) and chromosome specific DNA libraries indicate that some chromosomes are more sensitive for radiation induced aberration formation than others. Chromosome No. 4 in human and chromosome No. 8 in Chinese hamster have been found to involve more in exchange aberrations than others, when calculated on the basis of their DNA content. Painting with arm specific chromosome libraries indicate that the frequencies of radiation induced intra-chromosome exchanges (i.e., between the arms of a chromosome, such as centric rings and inversions) are far in excess than one would expect on the basis of the frequencies of observed inter-chromosomal exchanges. The possible factors leading to the observed heterogeneity will be discussed

Volume perfusion CT imaging of cerebral vasospasm: diagnostic performance of different perfusion maps

Energy Technology Data Exchange (ETDEWEB)

Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Afat, Saif; Nikoubashman, Omid; Mueller, Marguerite; Wiesmann, Martin; Brockmann, Carolin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Schubert, Gerrit Alexander [RWTH Aachen University, Department of Neurosurgery, Aachen (Germany); Bier, Georg [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Brockmann, Marc A. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); University Hospital Mainz, Department of Neuroradiology, Mainz (Germany)

2016-08-15

In this study, we aimed to evaluate the diagnostic performance of different volume perfusion CT (VPCT) maps regarding the detection of cerebral vasospasm compared to angiographic findings. Forty-one datasets of 26 patients (57.5 ± 10.8 years, 18 F) with subarachnoid hemorrhage and suspected cerebral vasospasm, who underwent VPCT and angiography within 6 h, were included. Two neuroradiologists independently evaluated the presence and severity of vasospasm on perfusion maps on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting <50 %, 2 - vasospasm affecting >50 % of vascular territory). A third neuroradiologist independently assessed angiography for the presence and severity of vasospasm on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting < 50 %, 2 - vasospasm affecting > 50 % of vessel diameter). Perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to drain (TTD) were evaluated regarding diagnostic accuracy for cerebral vasospasm with angiography as reference standard. Correlation analysis of vasospasm severity on perfusion maps and angiographic images was performed. Furthermore, inter-reader agreement was assessed regarding findings on perfusion maps. Diagnostic accuracy for TTD and MTT was significantly higher than for all other perfusion maps (TTD, AUC = 0.832; MTT, AUC = 0.791; p < 0.001). TTD revealed higher sensitivity than MTT (p = 0.007). The severity of vasospasm on TTD maps showed significantly higher correlation levels with angiography than all other perfusion maps (p ≤ 0.048). Inter-reader agreement was (almost) perfect for all perfusion maps (kappa ≥ 0.927). The results of this study indicate that TTD maps have the highest sensitivity for the detection of cerebral vasospasm and highest correlation with angiography regarding the severity of vasospasm. (orig.)

Simulation of motor unit recruitment and microvascular unit perfusion: spatial considerations.

Science.gov (United States)

Fuglevand, A J; Segal, S S

1997-10-01

Muscle fiber activity is the principal stimulus for increasing capillary perfusion during exercise. The control elements of perfusion, i.e., microvascular units (MVUs), supply clusters of muscle fibers, whereas the control elements of contraction, i.e., motor units, are composed of fibers widely scattered throughout muscle. The purpose of this study was to examine how the discordant spatial domains of MVUs and motor units could influence the proportion of open capillaries (designated as perfusion) throughout a muscle cross section. A computer model simulated the locations of perfused MVUs in response to the activation of up to 100 motor units in a muscle with 40,000 fibers and a cross-sectional area of 100 mm2. The simulation increased contraction intensity by progressive recruitment of motor units. For each step of motor unit recruitment, the percentage of active fibers and the number of perfused MVUs were determined for several conditions: 1) motor unit fibers widely dispersed and motor unit territories randomly located (which approximates healthy human muscle), 2) regionalized motor unit territories, 3) reversed recruitment order of motor units, 4) densely clustered motor unit fibers, and 5) increased size but decreased number of motor units. The simulations indicated that the widespread dispersion of motor unit fibers facilitates complete capillary (MVU) perfusion of muscle at low levels of activity. The efficacy by which muscle fiber activity induced perfusion was reduced 7- to 14-fold under conditions that decreased the dispersion of active fibers, increased the size of motor units, or reversed the sequence of motor unit recruitment. Such conditions are similar to those that arise in neuromuscular disorders, with aging, or during electrical stimulation of muscle, respectively.

An Innovative Hyperbaric Hypothermic Machine Perfusion Protects the Liver from Experimental Preservation Injury

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Ferdinando A. Giannone

2012-01-01

Full Text Available Purpose. Hypothermic machine perfusion systems seem more effective than the current static storage to prevent cold ischemic liver injury. Thus, we test an innovative hyperbaric hypothermic machine perfusion (HHMP, which combines hyperbaric oxygenation of the preservation solution and continuous perfusion of the graft. Methods. Rat livers were preserved with Celsior solution according to 4 different modalities: normobaric static preservation; hyperbaric static preservation at 2 atmosphere absolute (ATA; normobaric dynamic preservation, with continuous perfusion; hyperbaric dynamic preservation, with continuous perfusion at 2 ATA. After 24 h cold preservation, we assessed different parameters. Results. Compared to baseline, livers preserved with the current static storage showed severe ultrastructural damage, glycogen depletion and an increased oxidative stress. Normobaric perfused livers showed improved hepatocyte ultrastructure and ameliorated glycogen stores, but they still suffered a significant oxidative damage. The addition of hyperbaric oxygen produces an extra benefit by improving oxidative injury and by inducing endothelial NO synthase (eNOS gene expression. Conclusions. Preservation by means of the present innovative HHMP reduced the liver injury occurring after the current static cold storage by lowering glycogen depletion and oxidative damage. Interestingly, only the use of hyperbaric oxygen was associated to a blunted oxidative stress and an increased eNOS gene expression.

Improved left ventricular function and perfusion at rest after successful transluminal coronary angioplasty

International Nuclear Information System (INIS)

Klepzig, H.; Kaltenbach, M.; Standke, R.; Maul, F.D.; Hoer, G.

1991-01-01

The purpose of this study was to evaluate left ventricular function and perfusion at rest before and after percutaneous transluminal coronary angioplasty. In consecutive 69 patients in whom coronary stenoses were dilated, the radionuclide left ventricular ejection fraction at rest increased significantly. In 26 of these patients, the ejection fraction increased by at least 4%. In these patients, exercise-induced ischemic ST depression had been more pronounced than in the others. 36 other patients underwent 201 Tl myocardial scintigraphy before and after angioplasty. Twelve patients in whom pre-PTCA images had revealed regions with irreversible 201 Tl uptake defects, showed normal 201 Tl distribution patterns on post-PTCA scintigrams. Post-exercise 201 Tl uptake (representing myocardial perfusion and metabolic activity) during pre-PTCA exercise stress tests was significantly lower in these cases. It is concluded that PTCA can improve left ventricular function and perfusion at rest. This improvement is most obvious in patients with pronounced exercise-induced myocardial ischemia as diagnosed by typical ST segment depression and reduced thallium uptake. (orig.) [de

Myocardial perfusion in patients with left bundle branch block and without coronary artery disease

International Nuclear Information System (INIS)

Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa; Honda, Minoru

1992-01-01

For the evaluation of myocardial perfusion in patients with left bundle branch block (LBBB), we performed exercise stress (Ex)-redistribution (RD) myocardial tomography with thallium-201 ( 201 Tl) in 23 patients with LBBB and without coronary artery disease (CAD). Myocardial images in patients with LBBB were compared with those of 9 patients with CAD who showed Ex induced transient septal defect. Bull'-eye maps ( 201 Tl distribution maps at Ex and RD and 201 Tl washout rate [WOR] map) were made from myocardial tomograms. In 23 patients with LBBB, 15 patients (65%) developed myocardial perfusion abnormality. In 10 (67%) of these 15 patients, transient perfusion defect appeared in the entire septum (diffuse type). On the other hand in 5 patients (33%), localized fixed perfusion defect developed at the boundary between septum and anterior wall (focal type). In focal type, every patient had other disease such as hypertension, aortic stenosis or sick sinus syndrome. While in patients with diffuse type, other diseases were observed in 30% (p 201 Tl WOR and 201 Tl uptake ratio of septum to lateral wall indicated that exercise induced septal defect was slighter in diffuse type than CAD. These points might be useful to differentiate whether CAD participates in the septal defect or not in patients with LBBB. (author)

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

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

2015-03-15

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

Nuclear magnetic resonance of perfused tissue

International Nuclear Information System (INIS)

Harpen, M.D.; Allison, R.C.

1986-01-01

The effect of perfusion on the NMR signal observed in NMR imaging is studied in a phantom and in two isolated perfused canine lungs. It is observed that perfusion in tissue has little effect on longitudinal relaxation times. Transverse relaxation rates are observed to correlate linearly with rates of perfusion, in accordance with a model presented. (author)

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

NARCIS (Netherlands)

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

2016-01-01

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

Comparison of exogenous adenosine and voluntary exercise on human skeletal muscle perfusion and perfusion heterogeneity

DEFF Research Database (Denmark)

Heinonen, Ilkka H.A.; Kemppainen, Jukka; Kaskinoro, Kimmo

2010-01-01

Adenosine is a widely used pharmacological agent to induce a 'high flow' control condition to study the mechanisms of exercise hyperemia, but it is not known how well adenosine infusion depicts exercise-induced hyperemia especially in terms of blood flow distribution at the capillary level in hum...

DNA double-strand breaks in blood lymphocytes induced by two-day 99mTc-MIBI myocardial perfusion scintigraphy.

Science.gov (United States)

Rief, Matthias; Hartmann, Lisa; Geisel, Dominik; Richter, Felicitas; Brenner, Winfried; Dewey, Marc

2018-07-01

To investigate DNA double-strand breaks (DSBs) in blood lymphocytes induced by two-day 99m Tc-MIBI myocardial perfusion scintigraphy (MPS) using y-H2AX immunofluorescence microscopy and to correlate the results with 99m Tc activity in blood samples. Eleven patients who underwent two-day MPS were included. DSB blood sampling was performed before and 5min, 1h and 24h after the first and second radiotracer injections. 99m Tc activity was measured in each blood sample. For immunofluorescence microscopy, distinct foci representing DSBs were quantified in lymphocytes after staining for the phosphorylated histone variant y-H2AX. The 99m Tc-MIBI activity measured on days one and two was similar (254±25 and 258±27 MBq; p=0.594). Compared with baseline DSB foci (0.09±0.05/cell), a significant increase was found at 5min (0.19±0.04/cell) and 1h (0.18±0.04/cell) after the first injection and at 5min and 1h after the second injection (0.21±0.03 and 0.19±0.04/cell, respectively; p=0.003 for both). At 24h after the first and second injections, the number of DSB foci had returned to baseline (0.06±0.02 and 0.12±0.05/cell, respectively). 99m Tc activity levels in peripheral blood samples correlated well with DSB counts (r=0.451). DSB counts reflect 99m Tc-MIBI activity after injection for two-day MPS, and might allow individual monitoring of biological effects of cardiac nuclear imaging. • Myocardial perfusion scintigraphy using 99m Tc induces time-dependent double-strand breaks (DSBs) • γ-H2AX immunofluorescence microscopy shows DSB as an early response to radiotracer injection • Activity measurements of 99m Tc correlate well with detected DSB • DSB foci induced by 99m Tc return to baseline 24h after radiotracer injection.

Methodology for ventilation/perfusion SPECT

DEFF Research Database (Denmark)

Bajc, Marika; Neilly, Brian; Miniati, Massimo

2010-01-01

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

Hydrostatic determinants of cerebral perfusion

International Nuclear Information System (INIS)

Wagner, E.M.; Traystman, R.J.

1986-01-01

We examined the cerebral blood flow response to alterations in perfusion pressure mediated through decreases in mean arterial pressure, increases in cerebrospinal fluid (CSF) pressure, and increases in jugular venous (JV) pressure in 42 pentobarbital anesthetized dogs. Each of these three pressures was independently controlled. Cerebral perfusion pressure was defined as mean arterial pressure minus JV or CSF pressure, depending on which was greater. Mean hemispheric blood flow was measured with the radiolabeled microsphere technique. Despite 30-mm Hg reductions in mean arterial pressure or increases in CSF or JV pressure, CBF did not change as long as the perfusion pressure remained greater than approximately 60 mm Hg. However, whenever perfusion pressure was reduced to an average of 48 mm Hg, cerebral blood flow decreased 27% to 33%. These results demonstrate the capacity of the cerebral vascular bed to respond similarly to changes in the perfusion pressure gradient obtained by decreasing mean arterial pressure, increasing JV pressure or increasing CSF pressure, and thereby support the above definition of cerebral perfusion pressure

Estimation of noise-free variance to measure heterogeneity.

Directory of Open Access Journals (Sweden)

Tilo Winkler

Full Text Available Variance is a statistical parameter used to characterize heterogeneity or variability in data sets. However, measurements commonly include noise, as random errors superimposed to the actual value, which may substantially increase the variance compared to a noise-free data set. Our aim was to develop and validate a method to estimate noise-free spatial heterogeneity of pulmonary perfusion using dynamic positron emission tomography (PET scans. On theoretical grounds, we demonstrate a linear relationship between the total variance of a data set derived from averages of n multiple measurements, and the reciprocal of n. Using multiple measurements with varying n yields estimates of the linear relationship including the noise-free variance as the constant parameter. In PET images, n is proportional to the number of registered decay events, and the variance of the image is typically normalized by the square of its mean value yielding a coefficient of variation squared (CV(2. The method was evaluated with a Jaszczak phantom as reference spatial heterogeneity (CV(r(2 for comparison with our estimate of noise-free or 'true' heterogeneity (CV(t(2. We found that CV(t(2 was only 5.4% higher than CV(r2. Additional evaluations were conducted on 38 PET scans of pulmonary perfusion using (13NN-saline injection. The mean CV(t(2 was 0.10 (range: 0.03-0.30, while the mean CV(2 including noise was 0.24 (range: 0.10-0.59. CV(t(2 was in average 41.5% of the CV(2 measured including noise (range: 17.8-71.2%. The reproducibility of CV(t(2 was evaluated using three repeated PET scans from five subjects. Individual CV(t(2 were within 16% of each subject's mean and paired t-tests revealed no difference among the results from the three consecutive PET scans. In conclusion, our method provides reliable noise-free estimates of CV(t(2 in PET scans, and may be useful for similar statistical problems in experimental data.

Variability of physiological brain perfusion in healthy subjects - A systematic review of modifiers. Considerations for multi-center ASL studies

DEFF Research Database (Denmark)

Clement, Patricia; Mutsaerts, Henk-Jan; Václavů, Lena

2018-01-01

was carried out for factors influencing quantitative measurements of perfusion in the human brain unrelated to medication use. A total of 58 perfusion modifiers were categorized into four groups. Several factors (e.g., caffeine, aging, and blood gases) were found to induce a considerable effect on brain...

Carex sempervirens tussocks induce spatial heterogeneity in litter decomposition, but not in soil properties, in a subalpine grassland in the Central Alps

Science.gov (United States)

Fei-Hai Yu; Martin Schutz; Deborah S. Page-Dumroese; Bertil O. Krusi; Jakob Schneller; Otto Wildi; Anita C. Risch

2011-01-01

Tussocks of graminoids can induce spatial heterogeneity in soil properties in dry areas with discontinuous vegetation cover, but little is known about the situation in areas with continuous vegetation and no study has tested whether tussocks can induce spatial heterogeneity in litter decomposition. In a subalpine grassland in the Central Alps where vegetation cover is...

Heterogeneous delay-induced asynchrony and resonance in a small-world neuronal network system

Science.gov (United States)

Yu, Wen-Ting; Tang, Jun; Ma, Jun; Yang, Xianqing

2016-06-01

A neuronal network often involves time delay caused by the finite signal propagation time in a given biological network. This time delay is not a homogenous fluctuation in a biological system. The heterogeneous delay-induced asynchrony and resonance in a noisy small-world neuronal network system are numerically studied in this work by calculating synchronization measure and spike interval distribution. We focus on three different delay conditions: double-values delay, triple-values delay, and Gaussian-distributed delay. Our results show the following: 1) the heterogeneity in delay results in asynchronous firing in the neuronal network, and 2) maximum synchronization could be achieved through resonance given that the delay values are integer or half-integer times of each other.

Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging.

Directory of Open Access Journals (Sweden)

Mark A Lum

Full Text Available To evaluate the ability of IA MR perfusion to characterize meningioma blood supply.Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA and intravenous (IV T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA dural, internal carotid artery (ICA dural, or pial. MR perfusion data regions of interest (ROIs were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM, relative cerebral blood flow (rCBF, relative cerebral blood volume (rCBV, and mean transit time (MTT. Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling.18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11, ICA dural (n = 4, or pial (n = 3. FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion.

Pulmonary perfusion ''without ventilation''

International Nuclear Information System (INIS)

Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

1983-01-01

An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

MicroRNA-93 controls perfusion recovery after hindlimb ischemia by modulating expression of multiple genes in the cell cycle pathway.

Science.gov (United States)

Hazarika, Surovi; Farber, Charles R; Dokun, Ayotunde O; Pitsillides, Achillieas N; Wang, Tao; Lye, R John; Annex, Brian H

2013-04-30

MicroRNAs are key regulators of gene expression in response to injury, but there is limited knowledge of their role in ischemia-induced angiogenesis, such as in peripheral arterial disease. Here, we used an unbiased strategy and took advantage of different phenotypic outcomes that follow surgically induced hindlimb ischemia between inbred mouse strains to identify key microRNAs involved in perfusion recovery from hindlimb ischemia. From comparative microRNA profiling between inbred mouse strains that display profound differences in their extent of perfusion recovery after hindlimb ischemia, we found that the mouse strain with higher levels of microRNA-93 (miR-93) in hindlimb muscle before ischemia and the greater ability to upregulate miR-93 in response to ischemia had better perfusion recovery. In vitro, overexpression of miR-93 attenuated hypoxia-induced apoptosis in both endothelial and skeletal muscle cells and enhanced proliferation in both cell types. In addition, miR-93 overexpression enhanced endothelial cell tube formation. In vivo, miR-93 overexpression enhanced capillary density and perfusion recovery from hindlimb ischemia, and antagomirs to miR-93 attenuated perfusion recovery. Both in vitro and in vivo modulation of miR-93 resulted in alterations in the expression of >1 cell cycle pathway gene in 2 different cell types. Our data indicate that miR-93 enhances perfusion recovery from hindlimb ischemia by modulation of multiple genes that coordinate the functional pathways of cell proliferation and apoptosis. Thus, miR-93 is a strong potential target for pharmacological modulation to promote angiogenesis in ischemic tissue.

Mastication induces long-term increases in blood perfusion of the trigeminal principal nucleus.

Science.gov (United States)

Viggiano, A; Manara, R; Conforti, R; Paccone, A; Secondulfo, C; Lorusso, L; Sbordone, L; Di Salle, F; Monda, M; Tedeschi, G; Esposito, F

2015-12-17

Understanding mechanisms for vessel tone regulation within the trigeminal nuclei is of great interest because some headache syndromes are due to dysregulation of such mechanisms. Previous experiments on animal models suggest that mastication may alter neuron metabolism and blood supply in these nuclei. To investigate this hypothesis in humans, arterial spin-labeling magnetic resonance imaging (MRI) was used to measure blood perfusion within the principal trigeminal nucleus (Vp) and in the dorsolateral-midbrain (DM, including the mesencephalic trigeminal nucleus) in healthy volunteers, before and immediately after a mastication exercise consisting of chewing a gum on one side of the mouth for 1 h at 1 bite/s. The side preference for masticating was evaluated with a chewing test and the volume of the masseter muscle was measured on T1-weighted MRI scans. The results demonstrated that the mastication exercise caused a perfusion increase within the Vp, but not in the DM. This change was correlated to the preference score for the side where the exercise took place. Moreover, the basal Vp perfusion was correlated to the masseter volume. These results indicate that the local vascular tone of the trigeminal nuclei can be constitutively altered by the chewing practice and by strong or sustained chewing. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Outcome of Patients With Adenosine-Induced ST Segment Depression and Normal Myocardial Perfusion

International Nuclear Information System (INIS)

El-Refaei, S.; Selim, M.

2011-01-01

The aim of the present study was to determine the outcome of patients with normal MPS and adenosine-induced ST segment depression. A total of 1867 patients underwent adenosine Tc99m-tetrofosmin MPS in nuclear medicine unit in Saudi German Hospital, Saudi Arabia, between January 2004 and May 2008. Their ECGs were checked for ST segment depression during adenosine infusion. All patients with ≥ 1 mm horizontal or down-sloping ST segment depression or≥ 1.5 mm up-sloping ST segment depression were included in the study. Fifty-six patients met our inclusion criteria, of which 45 (80%) were females. During the follow-up period, a total of 15 of patients ended up doing coronary angiography, either for high clinical suspicion or following a second positive MPS performed 6-18 months after the first study. Seven of them were positive for coronary artery disease and were subsequently treated with revascularization procedure, and 8 returned either normal angiography or non-obstructive coronary artery disease. Male diabetic smoking patients were more prevalent and underwent revascularization. The patients were followed up for a mean of 22.8 ±7.8 months. No cardiac deaths or myocardial infarctions were reported. It could be concluded that adenosine-induced ST segment depression in patients with normal myocardial perfusion was a benign finding and did not increase the very low risk of cardiac events in those patients. However, male smokers and/or diabetics might need further investigation. This suggestion needs further evaluation

Evaluation of femoral perfusion in a rabbit model of steroid-induced osteonecrosis by dynamic contrast-enhanced MRI with a high magnetic field MRI system.

Science.gov (United States)

Hayashi, Shigeki; Fujioka, Mikihiro; Ikoma, Kazuya; Saito, Masazumi; Ueshima, Keiichiro; Ishida, Masashi; Kuribayashi, Masaaki; Ikegami, Akira; Mazda, Osam; Kubo, Toshikazu

2015-04-01

To evaluate perfusion during the early phase after steroid administration in vivo using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with a high magnetic field MRI system. The main pathogenesis of steroid-induced osteonecrosis is considered to be ischemia. A single dose of methylprednisolone (MPSL) was injected into nine rabbits. DCE-MRI was performed for these rabbits before MPSL administration and 1, 5, 10, and 14 days after administration. Time-signal intensity curves were created for each femur based on the signal intensity to evaluate perfusion. Enhancement ratio (ER), initial slope (IS), and area under the curve (AUC) were calculated and the value before MPSL administration and the minimal value after administration were compared statistically. ER, IS, and AUC values after MPSL administration significantly decreased (P < 0.05, P < 0.01, and P < 0.01, respectively). All of them decreased by the 5th day in 56% of the femora and by the 14th day in 83%, and some femora even showed a decrease from the 1st day. In this study, decreased perfusion in the femora after steroid administration was proven. Additionally, we could show that it occurred from the early days after steroid administration. © 2014 Wiley Periodicals, Inc.

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

International Nuclear Information System (INIS)

Tutcu, Semra; Serter, Selim; Kaya, Yavuz; Kara, Eray; Nese, Nalan; Pekindil, Goekhan; Coskun, Teoman

2010-01-01

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

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

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

2010-08-15

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

Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

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Reske, S.N.; Schoen, S.; Schmitt, W.; Knopp, R.; Winkler, C.; Machulla, H.J.

1986-08-01

The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid /sup 14/C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides.

Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

International Nuclear Information System (INIS)

Reske, S.N.; Schoen, S.; Schmitt, W.; Knopp, R.; Winkler, C.; Machulla, H.J.

1986-01-01

The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid 14 C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides. (orig.)

ABCD1 dysfunction alters white matter microvascular perfusion

DEFF Research Database (Denmark)

Lauer, Arne; Da, Xiao; Hansen, Mikkel Bo

2017-01-01

Cerebral X-linked adrenoleukodystrophy is a devastating neurodegenerative disorder caused by mutations in the ABCD1 gene, which lead to a rapidly progressive cerebral inflammatory demyelination in up to 60% of affected males. Selective brain endothelial dysfunction and increased permeability...... of the blood–brain barrier suggest that white matter microvascular dysfunction contributes to the conversion to cerebral disease. Applying a vascular model to conventional dynamic susceptibility contrast magnetic reson- ance perfusion imaging, we demonstrate that lack of ABCD1 function causes increased...... capillary flow heterogeneity in asymptom- atic hemizygotes predominantly in the white matter regions and developmental stages with the highest probability for conversion to cerebral disease. In subjects with ongoing inflammatory demyelination we observed a sequence of increased capillary flow hetero...

Contralateral thalamic hypoperfusion on brain perfusion SPECT

International Nuclear Information System (INIS)

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

2000-01-01

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

Magnetic resonance perfusion imaging without contrast media

International Nuclear Information System (INIS)

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

2010-01-01

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

MRI and MRA of kidney transplants - evaluation of vessels and perfusion

International Nuclear Information System (INIS)

Wiesner, W.; Pfammatter, T.; Krestin, G.P.; Debatin, J.F.

1998-01-01

Purpose: To document the value of fast contrast enhanced-sequences in the assessment of the vascular supply and parenchymal perfusion in renal transplants. Patients: 18 recipients of a renal transplant were examined with a 1.5-Tesla-MR-system. The protocol included fast contrast enhanced 3D MR angiography and coronal 2D GRE sequences. The transplant artery and vein were assessed as well as regional parenchymal perfusion. Results: 3D MRA detected three transplant artery stenoses and one occlusion. In addition, two renal vein thromboses and one compression were identified. Perfusion deficits were documented in 8 renal transplants: Renal infarction (n=4), cortical necrosis (n=2), acute tubular necrosis (n=1) and venous ischemia (n=1). Fluid collections were documented as well as dilatation of the collecting system and abnormalities of the surrounding tissues. Conclusion: Contrast enhanced MRI and MRA permit a comprehensive assessment of renal transplants without inducing nephrotoxicity. (orig.) [de

Hepatic arterial perfusion increases in the early stage of severe acute pancreatitis patients: Evaluation by perfusion computed tomography

International Nuclear Information System (INIS)

Koyasu, Sho; Isoda, Hiroyoshi; Tsuji, Yoshihisa; Yamamoto, Hiroshi; Matsueda, Kazuhiro; Watanabe, Yuji; Chiba, Tsutomu; Togashi, Kaori

2012-01-01

Purpose: Although hepatic perfusion abnormalities have been reported in patients with acute pancreatitis, hepatic perfusion with severe acute pancreatitis (SAP) has not been quantitatively evaluated in humans. Therefore, we investigated hepatic perfusion in patients with SAP using perfusion CT. Materials and methods: Hepatic perfusion CT was performed in 67 patients with SAP within 3 days after symptom onset. The patients were diagnosed as having SAP according to the Atlanta criteria. Fifteen cases were established as a control group. Perfusion CT was obtained for 54 s beginning with a bolus injection of 40 ml of contrast agent (600–630 mgI/kg) at a flow rate of 4 ml/s. Perfusion data were analyzed by the dual-input maximum slope method to obtain hepatic arterial perfusion (HAP) and hepatic portal perfusion (HPP). Finally, we compared HAP and HPP in SAP patients with those in the control group, respectively. Results: Average HAP was significantly higher in SAP patients than in the control group (75.1 ± 38.0 vs. 38.2 ± 9.0 ml/min/100 ml; p < 0.001). There was no significant difference in average HPP between SAP patients and the control group (206.7 ± 54.9 vs. 204.4 ± 38.5 ml/min/100 ml; p = 0.92). Conclusion: Using quantitative analysis on perfusion CT, we first demonstrated an increase of HAP in the right hepatic lobe in SAP patients.

Ex Vivo Normothermic Perfusion Induces Donor-Derived Leukocyte Mobilization and Removal Prior to Renal Transplantation

Directory of Open Access Journals (Sweden)

John P. Stone

2016-11-01

Discussion: We demonstrate that ex vivo normothermic perfusion initiates an inflammatory cytokine storm and release of mitochondrial and genomic DNA. This is likely to be responsible for immune cell activation and mobilization into the circuit prior to transplantation. Interestingly this did not have an impact on renal function. These data therefore suggest that normothermic perfusion can be used to immunodeplete and to saturate the pro-inflammatory capacity of donor kidneys prior to transplantation.

Fundamental supply of skin blood flow in the Chinese Han population: Measurements by a full-field laser perfusion imager.

Science.gov (United States)

Fei, W; Xu, S; Ma, J; Zhai, W; Cheng, S; Chang, Y; Wang, X; Gao, J; Tang, H; Yang, S; Zhang, X

2018-05-08

Skin blood flow is believed to link with many diseases, and shows a significant heterogeneity. There are several papers on basal cutaneous microcirculation perfusion in different races, while the data in Chinese is vacant. The aim was to establish the database of absolute fundamental supply of skin blood flow in the Chinese Han population. With a full-field laser perfusion imager (FLPI), the skin blood flow can be quantified. Cutaneous perfusion values were determined in 17 selected skin areas in 406 healthy participants aged between 20 and 80 years (mean 35.05 ± 11.33). Essential parameters such as weight, height were also measured and values of BMI were calculated. The perfusion values were reported in Arbitrary Perfusion Units (APU). The highest cutaneous perfusion value fell on eyelid (931.20 ± 242.59 in male and 967.83 ± 225.49 in female), and pretibial had the lowest value (89.09 ± 30.28 in male and 85.08 ± 33.59 in female). The values were higher in men than women on the bank of fingertips, nose, forehead, cheek, neck and earlobe (P < .05). Perfusion values on stretch and flexion side of forearm had negative correlation with age (P = .01 and P = 4.88 × 10 -3 , respectively) in male. Abdomen was negatively correlated with BMI in both gender (P = .02, respectively). Skin blood flow values vary with skin regions. There is a tendency to measure higher perfusion values in men than in women. And the values are irrelevant with age or BMI. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Improved visualization of delayed perfusion in lung MRI

International Nuclear Information System (INIS)

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

2011-01-01

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

Ventilation-perfused studies using SPECT

International Nuclear Information System (INIS)

Zwijnenburg, A.

1989-01-01

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

Automatic assessment of cardiac perfusion MRI

DEFF Research Database (Denmark)

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

2004-01-01

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

Can preoperative myocardial perfusion scintigraphy predict changes in left ventricular perfusion and function after coronary artery bypass graft surgery?

DEFF Research Database (Denmark)

Eckardt, Rozy; Kjeldsen, Bo Juel; Johansen, Allan

2012-01-01

OBJECTIVESWe wanted to evaluate whether preoperative myocardial perfusion scintigraphy (MPS) could predict changes in cardiac symptoms and postoperative myocardial perfusion and left ventricular function after coronary artery bypass grafting (CABG).METHODSNinety-two patients with stable angina...... in 26%. Left ventricular ejection fraction (LVEF), which was normal before operation in 45%, improved in 40% of all patients. The increase in LVEF was not related to the preoperative pattern of perfusion defects. Of 30 patients with normalized perfusion after CABG, 29 (97%) had reversible defects...... that reversible or partly reversible perfusion defects at a preoperative MPS have a high chance of normalized myocardial perfusion assessed by MPS 6 months after operation. Normal perfusion is obtained almost exclusively in territories with reversible ischaemia. Symptoms improved in nearly all patients and LVEF...

Ventilation/Perfusion Positron Emission Tomography—Based Assessment of Radiation Injury to Lung

International Nuclear Information System (INIS)

Siva, Shankar; Hardcastle, Nicholas; Kron, Tomas; Bressel, Mathias; Callahan, Jason; MacManus, Michael P.; Shaw, Mark; Plumridge, Nikki; Hicks, Rodney J.; Steinfort, Daniel; Ball, David L.; Hofman, Michael S.

2015-01-01

Purpose: To investigate 68 Ga-ventilation/perfusion (V/Q) positron emission tomography (PET)/computed tomography (CT) as a novel imaging modality for assessment of perfusion, ventilation, and lung density changes in the context of radiation therapy (RT). Methods and Materials: In a prospective clinical trial, 20 patients underwent 4-dimensional (4D)-V/Q PET/CT before, midway through, and 3 months after definitive lung RT. Eligible patients were prescribed 60 Gy in 30 fractions with or without concurrent chemotherapy. Functional images were registered to the RT planning 4D-CT, and isodose volumes were averaged into 10-Gy bins. Within each dose bin, relative loss in standardized uptake value (SUV) was recorded for ventilation and perfusion, and loss in air-filled fraction was recorded to assess RT-induced lung fibrosis. A dose-effect relationship was described using both linear and 2-parameter logistic fit models, and goodness of fit was assessed with Akaike Information Criterion (AIC). Results: A total of 179 imaging datasets were available for analysis (1 scan was unrecoverable). An almost perfectly linear negative dose-response relationship was observed for perfusion and air-filled fraction (r 2 =0.99, P<.01), with ventilation strongly negatively linear (r 2 =0.95, P<.01). Logistic models did not provide a better fit as evaluated by AIC. Perfusion, ventilation, and the air-filled fraction decreased 0.75 ± 0.03%, 0.71 ± 0.06%, and 0.49 ± 0.02%/Gy, respectively. Within high-dose regions, higher baseline perfusion SUV was associated with greater rate of loss. At 50 Gy and 60 Gy, the rate of loss was 1.35% (P=.07) and 1.73% (P=.05) per SUV, respectively. Of 8/20 patients with peritumoral reperfusion/reventilation during treatment, 7/8 did not sustain this effect after treatment. Conclusions: Radiation-induced regional lung functional deficits occur in a dose-dependent manner and can be estimated by simple linear models with 4D-V/Q PET/CT imaging. These

Ventilation/Perfusion Positron Emission Tomography—Based Assessment of Radiation Injury to Lung

Energy Technology Data Exchange (ETDEWEB)

Siva, Shankar, E-mail: shankar.siva@petermac.org [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville (Australia); Hardcastle, Nicholas [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong (Australia); Kron, Tomas [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne (Australia); Bressel, Mathias [Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne (Australia); Callahan, Jason [Centre for Molecular Imaging, Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); MacManus, Michael P.; Shaw, Mark; Plumridge, Nikki [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne (Australia); Hicks, Rodney J. [Centre for Molecular Imaging, Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Department of Medicine, University of Melbourne, Parkville (Australia); Steinfort, Daniel [Department of Medicine, University of Melbourne, Parkville (Australia); Department of Cancer Medicine, Peter MacCallum Cancer Centre, East Melbourne (Australia); Ball, David L. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne (Australia); Hofman, Michael S. [Centre for Molecular Imaging, Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Department of Medicine, University of Melbourne, Parkville (Australia)

2015-10-01

Purpose: To investigate {sup 68}Ga-ventilation/perfusion (V/Q) positron emission tomography (PET)/computed tomography (CT) as a novel imaging modality for assessment of perfusion, ventilation, and lung density changes in the context of radiation therapy (RT). Methods and Materials: In a prospective clinical trial, 20 patients underwent 4-dimensional (4D)-V/Q PET/CT before, midway through, and 3 months after definitive lung RT. Eligible patients were prescribed 60 Gy in 30 fractions with or without concurrent chemotherapy. Functional images were registered to the RT planning 4D-CT, and isodose volumes were averaged into 10-Gy bins. Within each dose bin, relative loss in standardized uptake value (SUV) was recorded for ventilation and perfusion, and loss in air-filled fraction was recorded to assess RT-induced lung fibrosis. A dose-effect relationship was described using both linear and 2-parameter logistic fit models, and goodness of fit was assessed with Akaike Information Criterion (AIC). Results: A total of 179 imaging datasets were available for analysis (1 scan was unrecoverable). An almost perfectly linear negative dose-response relationship was observed for perfusion and air-filled fraction (r{sup 2}=0.99, P<.01), with ventilation strongly negatively linear (r{sup 2}=0.95, P<.01). Logistic models did not provide a better fit as evaluated by AIC. Perfusion, ventilation, and the air-filled fraction decreased 0.75 ± 0.03%, 0.71 ± 0.06%, and 0.49 ± 0.02%/Gy, respectively. Within high-dose regions, higher baseline perfusion SUV was associated with greater rate of loss. At 50 Gy and 60 Gy, the rate of loss was 1.35% (P=.07) and 1.73% (P=.05) per SUV, respectively. Of 8/20 patients with peritumoral reperfusion/reventilation during treatment, 7/8 did not sustain this effect after treatment. Conclusions: Radiation-induced regional lung functional deficits occur in a dose-dependent manner and can be estimated by simple linear models with 4D-V/Q PET

Induction of Inducible Nitric Oxide Synthase by Lipopolysaccharide and the Influences of Cell Volume Changes, Stress Hormones and Oxidative Stress on Nitric Oxide Efflux from the Perfused Liver of Air-Breathing Catfish, Heteropneustes fossilis.

Directory of Open Access Journals (Sweden)

Mahua G Choudhury

Full Text Available The air-breathing singhi catfish (Heteropneustes fossilis is frequently being challenged by bacterial contaminants, and different environmental insults like osmotic, hyper-ammonia, dehydration and oxidative stresses in its natural habitats throughout the year. The main objectives of the present investigation were to determine (a the possible induction of inducible nitric oxide synthase (iNOS gene with enhanced production of nitric oxide (NO by intra-peritoneal injection of lipopolysaccharide (LPS (a bacterial endotoxin, and (b to determine the effects of hepatic cell volume changes due to anisotonicity or by infusion of certain metabolites, stress hormones and by induction of oxidative stress on production of NO from the iNOS-induced perfused liver of singhi catfish. Intra-peritoneal injection of LPS led to induction of iNOS gene and localized tissue specific expression of iNOS enzyme with more production and accumulation of NO in different tissues of singhi catfish. Further, changes of hydration status/cell volume, caused either by anisotonicity or by infusion of certain metabolites such as glutamine plus glycine and adenosine, affected the NO production from the perfused liver of iNOS-induced singhi catfish. In general, increase of hydration status/cell swelling due to hypotonicity caused decrease, and decrease of hydration status/cell shrinkage due to hypertonicity caused increase of NO efflux from the perfused liver, thus suggesting that changes in hydration status/cell volume of hepatic cells serve as a potent modulator for regulating the NO production. Significant increase of NO efflux from the perfused liver was also observed while infusing the liver with stress hormones like epinephrine and norepinephrine, accompanied with decrease of hydration status/cell volume of hepatic cells. Further, oxidative stress, caused due to infusion of t-butyl hydroperoxide and hydrogen peroxide separately, in the perfused liver of singhi catfish, resulted

High cell density suppresses BMP4-induced differentiation of human pluripotent stem cells to produce macroscopic spatial patterning in a unidirectional perfusion culture chamber.

Science.gov (United States)

Tashiro, Shota; Le, Minh Nguyen Tuyet; Kusama, Yuta; Nakatani, Eri; Suga, Mika; Furue, Miho K; Satoh, Taku; Sugiura, Shinji; Kanamori, Toshiyuki; Ohnuma, Kiyoshi

2018-04-19

Spatial pattern formation is a critical step in embryogenesis. Bone morphogenetic protein 4 (BMP4) and its inhibitors are major factors for the formation of spatial patterns during embryogenesis. However, spatial patterning of the human embryo is unclear because of ethical issues and isotropic culture environments resulting from conventional culture dishes. Here, we utilized human pluripotent stem cells (hiPSCs) and a simple anisotropic (unidirectional perfusion) culture chamber, which creates unidirectional conditions, to measure the cell community effect. The influence of cell density on BMP4-induced differentiation was explored during static culture using a conventional culture dish. Immunostaining of the early differentiation marker SSEA-1 and the mesendoderm marker BRACHYURY revealed that high cell density suppressed differentiation, with small clusters of differentiated and undifferentiated cells formed. Addition of five-fold higher concentration of BMP4 showed similar results, suggesting that suppression was not caused by depletion of BMP4 but rather by high cell density. Quantitative RT-PCR array analysis showed that BMP4 induced multi-lineage differentiation, which was also suppressed under high-density conditions. We fabricated an elongated perfusion culture chamber, in which proteins were transported unidirectionally, and hiPSCs were cultured with BMP4. At low density, the expression was the same throughout the chamber. However, at high density, SSEA-1 and BRACHYURY were expressed only in upstream cells, suggesting that some autocrine/paracrine factors inhibited the action of BMP4 in downstream cells to form the spatial pattern. Human iPSCs cultured in a perfusion culture chamber might be useful for studying in vitro macroscopic pattern formation in human embryogenesis. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Analysis of perfusion defects by causes other than acute pulmonary thromboembolism on contrast-enhanced dual-energy CT in consecutive 537 patients

International Nuclear Information System (INIS)

Kim, Bo Hyun; Seo, Joon Beom; Chae, Eun Jin; Lee, Hyun Joo; Hwang, Hye Jeon; Lim, Chaehun

2012-01-01

Objective: To assess causes, incidence and patterns of perfusion defects (PDs) on dual-energy perfusion CT angiography (DECTA) in clinically suspected acute pulmonary thromboembolisms (PTE). Materials and methods: Consecutive 537 patients who underwent DECTA for suspicion of PTE were retrospectively reviewed. After excluding patients with possible PTE or unsatisfactory perfusion map quality, 299 patients with 1697 lobes were included. The DECTA (Somatom Definition, Siemens) was performed at 140 kV and 80 kV. Color-coded perfusion images were obtained with a lung PBV application of the workstation software (Syngo Dual Energy). The presence, incidence, three patterns of PDs (wedge-shaped, heterogeneous, and regionally homogeneous), pulmonary diseases, and the matchedness between the PD and the disease extent were studied. Results: 315 of 1697 lobes (18.6%) in 156 of 299 patients (81.3%) showed PDs. Among them, 51 (3%), 257 (15.1%), and 7 (0.4%) lobes had PDs due to vascular, nonvascular, and unidentifiable causes, respectively. Vascular causes include: pulmonary arterial (PA) hypertension (0.7%), extrinsic occlusion of PA by fibrosis (0.6%), PA hypoplasia (0.6%), vasculitis (0.5%), cancer mass compressing PA, venous occlusion, AVM, and pulmonary angiosarcoma. Most of PDs were wedge-shaped and well-matched. Nonvascular causes include: mosaic attenuation (4.1%), emphysema (3.2%), interstitial fibrosis (1.6%), bronchitis (1.4%), GGO (1.2%), cellular bronchiolitis (1%), bronchiectasis, airway obstruction, compensaroty lung hyperinflation, air trapping, cor-pulmonale, bronchopneumonia, physiologic decreased ventilation, and segmental bronchial atresia. Most of PDs showed heterogeneous pattern and were not matched. Conclusions: Various vascular and nonvascular diseases cause PDs on DECTA. Each disease shows different pattern of PD depending on pathophysiology and physiologic compensation.

Ex-vivo machine perfusion for kidney preservation.

Science.gov (United States)

Hamar, Matyas; Selzner, Markus

2018-06-01

Machine perfusion is a novel strategy to decrease preservation injury, improve graft assessment, and increase organ acceptance for transplantation. This review summarizes the current advances in ex-vivo machine-based kidney preservation technologies over the last year. Ex-vivo perfusion technologies, such as hypothermic and normothermic machine perfusion and controlled oxygenated rewarming, have gained high interest in the field of organ preservation. Keeping kidney grafts functionally and metabolically active during the preservation period offers a unique chance for viability assessment, reconditioning, and organ repair. Normothermic ex-vivo kidney perfusion has been recently translated into clinical practice. Preclinical results suggest that prolonged warm perfusion appears superior than a brief end-ischemic reconditioning in terms of renal function and injury. An established standardized protocol for continuous warm perfusion is still not available for human grafts. Ex-vivo machine perfusion represents a superior organ preservation method over static cold storage. There is still an urgent need for the optimization of the perfusion fluid and machine technology and to identify the optimal indication in kidney transplantation. Recent research is focusing on graft assessment and therapeutic strategies.

Experimental study of CT perfusion in hepatitis, hepatic fibrosis and early stage of cirrhosis

International Nuclear Information System (INIS)

Guan Sheng; Zhao Weidong; Zhou Kangrong; Peng Weijun; Mao Jian; Tang Feng; Wang Yong; Cao Guang; Sun Fei

2005-01-01

Objective: To investigate the value of CT perfusion in the early diagnosis of hepatic diffuse disease. Methods: Fourteen male Wistar rats of control group and 14 of test group at stages of hepatitis, hepatic fibrosis, hepatic cirrhosis which were induced with diethylnitrosamine (DEN), were studied with CT perfusion respectively. CT perfusion data of different stages were compared and pathologic analysis were performed. Results: Density-time curves of CT perfusion were satisfactory and all perfusion data could be obtained. During the period of hepatitis developing into early stage of hepatic cirrhosis, hepatic artery flow (HAF) trended to increase in test group, mean transmit time (MTT) prolonged obviously, blood flow (BF) and volume (BV) declined. While in control group, HAF declined slightly, MTT, BV and BF increased. Statistic analysis showed the differences of HAF and MTT at different stages between control and test groups were significant (P<0.05 ); the differences of BV and BF between hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis in test group were significant (P<0.05), but no significant difference between hepatitis and hepatic fibrosis. The corresponding pathologic changes at stage of hepatitis was swelling of hepatic cells; sinusoids cap illarization and deposition of collagen in the extravascular Disse's spaces were the main changes relating to hepatic blood perfusion at stage of fibrosis and early stage of cirrhosis. Conclusion: The method of CT scan can reflect some changes of hepatic blood perfusion in rats with hepatitis, hepatic fibrosis and early stage of cirrhosis. The data of CT perfusion, especially the changes should be valuable for clinical early diagnosis, treatment and follow-up. (authors)

Active Oxygen Metabolites and Thromboxane in Phorbol Myristate Acetate Toxicity to the Isolated, Perfused Rat Lung.

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Carpenter, Laurie Jean

When administered intravenously or intratracheally to rats, rabbits and sheep, phorbol myristate acetate (PMA) produces changes in lung morphology and function are similar to those seen in humans with the adult respiratory distress syndrome (ARDS). Therefore, it is thought that information about the mechanism of ARDS development can be gained from experiments using PMA-treated animals. Currently, the mechanisms by which PMA causes pneumotoxicity are unknown. Results from other studies in rabbits and in isolated, perfused rabbit lungs suggest that PMA-induced lung injury is mediated by active oxygen species from neutrophils (PMN), whereas studies in sheep and rats suggest that PMN are not required for the toxic response. The role of PMN, active oxygen metabolites and thromboxane (TxA_2) in PMA-induced injury to isolated, perfused rat lungs (IPLs) was examined in this thesis. To determine whether PMN were required for PMA to produce toxicity to the IPL, lungs were perfused for 30 min with buffer containing various concentrations of PMA (in the presence or absence of PMN). When concentrations >=q57 ng/ml were added to medium devoid of added PMN, perfusion pressure and lung weight increased. When a concentration of PMA (14-28 ng/ml) that did not by itself cause lungs to accumulate fluid was added to the perfusion medium containing PMN (1 x 10 ^8), perfusion pressure increased, and lungs accumulated fluid. These results indicate that high concentrations of PMA produce lung injury which is independent of PMN, whereas injury induced by lower concentrations is PMN-dependent. To examine whether active oxygen species were involved in mediating lung injury induced by PMA and PMN, lungs were coperfused with the oxygen radical scavengers SOD and/or catalase. Coperfusion with either or both of these enzymes totally protected lungs against injury caused by PMN and PMA. These results suggest that active oxygen species (the hydroxyl radical in particular), mediate lung injury in

Perfusion based cell culture chips

DEFF Research Database (Denmark)

Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

2010-01-01

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

Brain Perfusion Changes in Intracerebral Hemorrhage

International Nuclear Information System (INIS)

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

2006-01-01

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

Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI.

Science.gov (United States)

Pizzini, Francesca B; Farace, Paolo; Manganotti, Paolo; Zoccatelli, Giada; Bongiovanni, Luigi G; Golay, Xavier; Beltramello, Alberto; Osculati, Antonio; Bertini, Giuseppe; Fabene, Paolo F

2013-07-01

Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment. Copyright © 2013 Elsevier Inc. All rights reserved.

Developing a Benchmarking Process in Perfusion: A Report of the Perfusion Downunder Collaboration

Science.gov (United States)

Baker, Robert A.; Newland, Richard F.; Fenton, Carmel; McDonald, Michael; Willcox, Timothy W.; Merry, Alan F.

2012-01-01

Abstract: Improving and understanding clinical practice is an appropriate goal for the perfusion community. The Perfusion Downunder Collaboration has established a multi-center perfusion focused database aimed at achieving these goals through the development of quantitative quality indicators for clinical improvement through benchmarking. Data were collected using the Perfusion Downunder Collaboration database from procedures performed in eight Australian and New Zealand cardiac centers between March 2007 and February 2011. At the Perfusion Downunder Meeting in 2010, it was agreed by consensus, to report quality indicators (QI) for glucose level, arterial outlet temperature, and pCO2 management during cardiopulmonary bypass. The values chosen for each QI were: blood glucose ≥4 mmol/L and ≤10 mmol/L; arterial outlet temperature ≤37°C; and arterial blood gas pCO2 ≥ 35 and ≤45 mmHg. The QI data were used to derive benchmarks using the Achievable Benchmark of Care (ABC™) methodology to identify the incidence of QIs at the best performing centers. Five thousand four hundred and sixty-five procedures were evaluated to derive QI and benchmark data. The incidence of the blood glucose QI ranged from 37–96% of procedures, with a benchmark value of 90%. The arterial outlet temperature QI occurred in 16–98% of procedures with the benchmark of 94%; while the arterial pCO2 QI occurred in 21–91%, with the benchmark value of 80%. We have derived QIs and benchmark calculations for the management of several key aspects of cardiopulmonary bypass to provide a platform for improving the quality of perfusion practice. PMID:22730861

Induced Human Decidual NK-Like Cells Improve Utero-Placental Perfusion in Mice.

Directory of Open Access Journals (Sweden)

Ricardo C Cavalli

Full Text Available Decidual NK (dNK cells, a distinct type of NK cell, are thought to regulate uterine spiral artery remodeling, a process that allows for increased blood delivery to the fetal-placental unit. Impairment of uterine spiral artery remodeling is associated with decreased placental perfusion, increased uterine artery resistance, and obstetric complications such as preeclampsia and intrauterine growth restriction. Ex vivo manipulation of human peripheral blood NK (pNK cells by a combination of hypoxia, TGFß-1 and 5-aza-2'-deoxycytidine yields cells with phenotypic and in vitro functional similarities to dNK cells, called idNK cells. Here, gene expression profiling shows that CD56Bright idNK cells derived ex vivo from human pNK cells, and to a lesser extent CD56Dim idNK cells, are enriched in the gene expression signature that distinguishes dNK cells from pNK cells. When injected into immunocompromised pregnant mice with elevated uterine artery resistance, idNK cells homed to the uterus and reduced the uterine artery resistance index, suggesting improved placental perfusion.

Non-contrast MRI perfusion angiosome in diabetic feet

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Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

2015-01-15

The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

Non-contrast MRI perfusion angiosome in diabetic feet

International Nuclear Information System (INIS)

Zheng, Jie; Hastings, Mary K.; Mueller, Michael J.; Muccigross, David; Hildebolt, Charles F.; Fan, Zhaoyang; Gao, Fabao; Curci, John

2015-01-01

The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

Regional perfusion and oxygenation of tumors upon methylxanthine derivative administration

International Nuclear Information System (INIS)

Kelleher, Debra K.; Thews, Oliver; Vaupel, Peter

1998-01-01

Purpose: The use of methylxanthine derivatives has been postulated as a means of increasing tumor perfusion and thus ameliorating tumor hypoxia. The aim of this study was to quantify and compare the effects of three methylxanthine derivatives: pentoxifylline (PX), torbafylline (TB), and HWA 138 (HW) on tumor perfusion and oxygenation. Methods and Materials: Anesthetized Sprague Dawley rats with DS-sarcomas implanted subcutaneously onto the hind foot dorsum were used in this study. Mean arterial blood pressure (MABP) was measured throughout experiments. Regional red blood cell (RBC) flux was monitored using a multichannel laser Doppler device and tumor oxygenation on a more global level was assessed polarographically using an O 2 -sensitive catheter electrode. The methylxanthine derivatives were administered as a single dose intraperitoneally (for PX 50 mg/kg; for TB and HW 75 mg/kg). Results: Following drug administration, initial decreases in MABP down to 75% of baseline values were observed for all three substances. PX, HW, and TB caused initial transient reductions in mean RBC flux followed by gradual increases to values of 137 ± 27 %, 139 ± 14 %, and 122 ± 14 % respectively at t = 60 min. Following a small initial decrease upon drug administration, O 2 partial pressure (pO 2 ) rose to 160 ± 31 %, 153 ± 34 %, and 121 ± 11 % for PX, HW, and TB, respectively at t = 60 min. At the end of the observation period (t = 90 min), increases in RBC flux and pO 2 were still evident. When individual tumors were considered, a variety of patterns (including opposing effects) for changes in RBC flux were seen, not necessarily reflected in the mean values. Thus, while the methylxanthine derivatives caused an increased average tumor perfusion, there is evidence suggesting that a redistribution of tumor blood flow occurs which may amplify preexisting heterogeneity. Conclusions: Substantial improvements in tumor oxygenation and perfusion were observed after administration of

Dual-energy perfusion-CT of pancreatic adenocarcinoma

International Nuclear Information System (INIS)

Klauß, M.; Stiller, W.; Pahn, G.; Fritz, F.; Kieser, M.; Werner, J.; Kauczor, H.U.; Grenacher, L.

2013-01-01

Purpose: To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. Materials and methods: 24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV p , 140 kV p , and weighted average (linearly blended M0.3) 120 kV p -equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. Results: In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV p -equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min −1 vs. 0.91 ± 0.04 min −1 (p −1 vs. 0.67 ± 0.05 *0.5 min −1 (p = 0.06) and 0.49 ± 0.07 min −1 vs. 1.28 ± 0.11 min −1 (p p the standard deviations of the kV p 120 kV p -equivalent values were manifestly smaller. Conclusion: Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV p in combination with the noise reduction at 140 kV p . Therefore using dual-energy perfusion data could improve the delineation of pancreatic carcinomas

Myocardial perfusion imaging for detection of silent myocardial ischemia

International Nuclear Information System (INIS)

Beller, G.A.

1988-01-01

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

Myocardial perfusion alterations observed months after radiotherapy are related to the cellular damage

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Dogan, I.; Sonmez, B. [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Nuclear Medicine; Sezen, O.; Zengin, A.Y.; Bahat, Z. [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Radiation Oncology; Yenilmez, E.; Yulug, E. [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Histology and Embryology; Abidin, I. [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Biophysics

2010-07-01

Myocardial perfusion scintigraphy (MPS) is one of the widely used tools to follow developing radiation-induced heart disease (RIHD). But the clinical significance of MPS defects has not been fully understood. We have investigated the biodistribution alterations related to perfusion defects following radiotherapy (RT) and showed coexisting morphological changes. Animals, methods: A total of 18 Wistar rats were divided into three groups (1 control and 2 irradiated groups). A single cardiac 20 Gy radiation dose was used to induce long term cardiac defects. Biodistribution studies with technetium ({sup 99m}Tc) sestamibi and histological evaluations were performed 4 and 6 months after irradiation. The percent radioactivity (%ID/g) was calculated for each heart. For determination of the myocardial damage, positive apoptotic cardiomyocytes, myocardial cell degeneration, myocardial fibrosis, vascular damage and ultrastructural structures were evaluated. Results: Six months after treatment, a significant drop of myocardial uptake was observed (p < 0.05). Irradiation-induced apoptosis rose within the first 4 months after radiation treatment and were stayed elevated until the end of the observation period (p < 0.05). Also, the irradiation has induced myocardial degeneration, perivascular and interstitial fibrosis in the heart at the end of six and four months (p < 0.01). The severity and extent of myocardial injury has became more evident at the end of six month (p < 0.05). At ultrastructural level, prominent changes have been observed in the capillary endothelial and myocardial cells. Conclusion: Our findings suggest that the reduced rest myocardial perfusion, occuring months after the radiation, indicates a serious myocard tissue damage which is characterized by myocardial degeneration and fibrosis. (orig.)

Myocardial perfusion alterations observed months after radiotherapy are related to the cellular damage

International Nuclear Information System (INIS)

Dogan, I.; Sonmez, B.; Sezen, O.; Zengin, A.Y.; Bahat, Z.; Yenilmez, E.; Yulug, E.; Abidin, I.

2010-01-01

Myocardial perfusion scintigraphy (MPS) is one of the widely used tools to follow developing radiation-induced heart disease (RIHD). But the clinical significance of MPS defects has not been fully understood. We have investigated the biodistribution alterations related to perfusion defects following radiotherapy (RT) and showed coexisting morphological changes. Animals, methods: A total of 18 Wistar rats were divided into three groups (1 control and 2 irradiated groups). A single cardiac 20 Gy radiation dose was used to induce long term cardiac defects. Biodistribution studies with technetium ( 99m Tc) sestamibi and histological evaluations were performed 4 and 6 months after irradiation. The percent radioactivity (%ID/g) was calculated for each heart. For determination of the myocardial damage, positive apoptotic cardiomyocytes, myocardial cell degeneration, myocardial fibrosis, vascular damage and ultrastructural structures were evaluated. Results: Six months after treatment, a significant drop of myocardial uptake was observed (p < 0.05). Irradiation-induced apoptosis rose within the first 4 months after radiation treatment and were stayed elevated until the end of the observation period (p < 0.05). Also, the irradiation has induced myocardial degeneration, perivascular and interstitial fibrosis in the heart at the end of six and four months (p < 0.01). The severity and extent of myocardial injury has became more evident at the end of six month (p < 0.05). At ultrastructural level, prominent changes have been observed in the capillary endothelial and myocardial cells. Conclusion: Our findings suggest that the reduced rest myocardial perfusion, occuring months after the radiation, indicates a serious myocard tissue damage which is characterized by myocardial degeneration and fibrosis. (orig.)

Magnetic Particle Imaging for Real-Time Perfusion Imaging in Acute Stroke.

Science.gov (United States)

Ludewig, Peter; Gdaniec, Nadine; Sedlacik, Jan; Forkert, Nils D; Szwargulski, Patryk; Graeser, Matthias; Adam, Gerhard; Kaul, Michael G; Krishnan, Kannan M; Ferguson, R Matthew; Khandhar, Amit P; Walczak, Piotr; Fiehler, Jens; Thomalla, Götz; Gerloff, Christian; Knopp, Tobias; Magnus, Tim

2017-10-24

The fast and accurate assessment of cerebral perfusion is fundamental for the diagnosis and successful treatment of stroke patients. Magnetic particle imaging (MPI) is a new radiation-free tomographic imaging method with a superior temporal resolution, compared to other conventional imaging methods. In addition, MPI scanners can be built as prehospital mobile devices, which require less complex infrastructure than computed tomography (CT) and magnetic resonance imaging (MRI). With these advantages, MPI could accelerate the stroke diagnosis and treatment, thereby improving outcomes. Our objective was to investigate the capabilities of MPI to detect perfusion deficits in a murine model of ischemic stroke. Cerebral ischemia was induced by inserting of a microfilament in the internal carotid artery in C57BL/6 mice, thereby blocking the blood flow into the medial cerebral artery. After the injection of a contrast agent (superparamagnetic iron oxide nanoparticles) specifically tailored for MPI, cerebral perfusion and vascular anatomy were assessed by the MPI scanner within seconds. To validate and compare our MPI data, we performed perfusion imaging with a small animal MRI scanner. MPI detected the perfusion deficits in the ischemic brain, which were comparable to those with MRI but in real-time. For the first time, we showed that MPI could be used as a diagnostic tool for relevant diseases in vivo, such as an ischemic stroke. Due to its shorter image acquisition times and increased temporal resolution compared to that of MRI or CT, we expect that MPI offers the potential to improve stroke imaging and treatment.

Detection of myocardial stunning with gated SPECT and its relationship with location, extension and severity of perfusion defects induced by exercise or pharmacologic stress

International Nuclear Information System (INIS)

Mut, F.; Beretta, M.; Vidal, I.; Rener, A.; Alonso, O.

2002-01-01

interpreted as true myocardial stunning and is related to the extent and severity of induced ischemia as determined by myocardial perfusion studies. It can be found either as a consequence of exercise or pharmacologic stimulus, and it might represent a parameter of additional clinical value for the management of patients with CAD

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

Science.gov (United States)

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

2013-03-01

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

Perfusion vector - a new method to quantify myocardial perfusion scintigraphy images: a simulation study with validation in patients

DEFF Research Database (Denmark)

Minarik, David; Senneby, Martin; Wollmer, Per

2015-01-01

Background The interpretation of myocardial perfusion scintigraphy (MPS) largely relies on visual assessment by the physician of the localization and extent of a perfusion defect. The aim of this study was to introduce the concept of the perfusion vector as a new objective quantitative method...

Placental perfusion - a human alternative

DEFF Research Database (Denmark)

Mose, Tina; Knudsen, Lisbeth E

2006-01-01

Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...... between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...

Combined T1-based perfusion MRI and MR angiography in kidney: First experience in normals and pathology

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Dujardin, Martine [Department of Radiology/BEFY, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: martine.dujardin@gmail.com; Luypaert, Rob [Department of Radiology/BEFY, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: rluypaer@vub.ac.be; Vandenbroucke, F. [Department of Radiology/BEFY, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: frederik.vandenbroucke@uzbrussel.be; Van der Niepen, Patricia [Department of Nephrology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: hemovnnp@az.vub.ac.be; Sourbron, Steven [Institute of Clinical Radiology, Ludwig-Maximilian-University Munich, Marchioninistrasse 15, 81377 Munchen (Germany)], E-mail: Steven.Sourbron@med.uni-muenchen.de; Verbeelen, Dierik [Department of Nephrology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: dierik.verbeelen@uzbrussel.be; Stadnik, T. [Department of Radiology/BEFY, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: tadeusz.stadnik@uzbrussel.be; Mey, Johan de [Department of Radiology/BEFY, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: johan.demey@uzbrussel.be

2009-03-15

Objectives: To investigate the feasibility of implementing quantitative T1-perfusion in the routine MRA-protocol and to obtain a first experience in normals and pathology. Materials and methods: For perfusion imaging, IR-prepared FLASH (one 4 mm slice at mid-renal level, TR 4.4 ms, TE 2.2 ms, TI 180 ms, FA 50 deg., matrix 128 x 256, bandwidth per pixel 300, 400 dynamics, temporal resolution 0.3 s, total measurement time 2 min) was applied during the injection of 10 ml of standard 0.5 mmol/ml Gadolinium-DTPA solution at 2 ml/s, followed by 3DCE-MRA with bolus tracking (TR 5.4, TE 1.4, FA 40 deg., matrix 192 x 512, NSA 1, slice thickness 1.5 mm), using a second dose of 0.1 mmol Gadolinium-DTPA per kg body weight with a maximum of 20 ml. The T1-weighted signals (perfusion data) were converted to tissue tracer concentrations and deconvolved with an inflow corrected AIF; blood flow, distribution volume, mean transit time and blood flow heterogeneity were derived. Results: MRA quality was uncompromised by the first bolus administered for perfusion purposes. In the normals, average cortical RBF, RVD and MTT were 1.2 ml/min/ml (S.D. 0.3 ml/min/ml), 0.4 ml/ml (S.D. 0.1 ml/ml) and 21 s (S.D. 4 s). These RBF values are lower than those found in the literature, probably due to residual AIF inflow effects. The sensitivity of the technique was sufficient to demonstrate altered perfusion in the examples of pathology. Conclusion: Combined quantitative T1-perfusion and MRA have a potential for noninvasive renovascular screening and may provide an anatomical and physiological evaluation of renal status.

The Groningen hypothermic liver perfusion pump : Functional evaluation of a new machine perfusion system

NARCIS (Netherlands)

van der Plaats, A.; Maathuis, M. H. J.; Hart, N. A. 't; 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.

2006-01-01

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,

Time-resolved, single-cell analysis of induced and programmed cell death via non-invasive propidium iodide and counterstain perfusion.

Science.gov (United States)

Krämer, Christina E M; Wiechert, Wolfgang; Kohlheyer, Dietrich

2016-09-01

Conventional propidium iodide (PI) staining requires the execution of multiple steps prior to analysis, potentially affecting assay results as well as cell vitality. In this study, this multistep analysis method has been transformed into a single-step, non-toxic, real-time method via live-cell imaging during perfusion with 0.1 μM PI inside a microfluidic cultivation device. Dynamic PI staining was an effective live/dead analytical tool and demonstrated consistent results for single-cell death initiated by direct or indirect triggers. Application of this method for the first time revealed the apparent antibiotic tolerance of wild-type Corynebacterium glutamicum cells, as indicated by the conversion of violet fluorogenic calcein acetoxymethyl ester (CvAM). Additional implementation of this method provided insight into the induced cell lysis of Escherichia coli cells expressing a lytic toxin-antitoxin module, providing evidence for non-lytic cell death and cell resistance to toxin production. Finally, our dynamic PI staining method distinguished necrotic-like and apoptotic-like cell death phenotypes in Saccharomyces cerevisiae among predisposed descendants of nutrient-deprived ancestor cells using PO-PRO-1 or green fluorogenic calcein acetoxymethyl ester (CgAM) as counterstains. The combination of single-cell cultivation, fluorescent time-lapse imaging, and PI perfusion facilitates spatiotemporally resolved observations that deliver new insights into the dynamics of cellular behaviour.

Vicarious audiovisual learning in perfusion education.

Science.gov (United States)

Rath, Thomas E; Holt, David W

2010-12-01

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

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

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Haas Norbert P

2008-04-01

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

Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

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Dowdle, S.C.; Human, D.G.; Mann, M.D. (Univ. of Cape Town (South Africa))

1990-08-01

Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis.

Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

International Nuclear Information System (INIS)

Dowdle, S.C.; Human, D.G.; Mann, M.D.

1990-01-01

Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis

Prona positioning in patients submitted to myocardial perfusion scintigraphy

International Nuclear Information System (INIS)

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

2011-01-01

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

Using a pulse oximeter to determine clinical depth of anesthesia-investigation of the utility of the perfusion index.

Science.gov (United States)

Krishnamohan, Anirudh; Siriwardana, Viraj; Skowno, Justin J

2016-11-01

Peripheral vasodilation is a well-recognized side effect of general anesthesia, and induces changes in the amplitude of the pulse plethysmograph (PPG) waveform. This can be continuously quantitaed using the Perfusion Index (PI), a ratio of the pulsatile to nonpulsatile signal amplitude in the PPG waveform. We hypothesized that the perfusion index would rise with the induction of anesthesia in children, and fall with emergence, and performed a prospective, observational study to test this. Our primary aim was to test whether the different clinical stages of anesthesia were associated with changes in the perfusion index, and the secondary aim was to test the correlation between the normalized perfusion index and the MAC value. Twenty-one patients between the ages of 1 and 18 undergoing minor procedures with no anticipated painful stimuli were recruited. Patients with significant illnesses were excluded. Data collection commenced with a preinduction baseline, and data were collected continuously, with event marking, until completion of the anesthesia and removal of the pulse oximeter. Data collected included perfusion index, heart rate, and anesthetic gas concentration values. A normalized perfusion index was calculated by subtracting the initial baseline perfusion index value from all perfusion index values, allowing changes, from a standardized initial baseline value of zero, to be analyzed. During induction, the mean normalized perfusion index rose from 0.0 to 4.2, and then declined to 0.470 when the patients returned to consciousness. P < 0.001 using repeated measures anova test. The normalized perfusion index was correlated with MAC values (r 2 = 0.33, 95% CI 0.18-0.47, P < 0.01). The perfusion index changed significantly during different stages of anesthesia. There is a significant correlation between the perfusion index, measured by pulse oximetry, and the MAC value, in pediatric patients undergoing minor procedures. © 2016 John Wiley & Sons Ltd.

Clinical application of cerebral dynamic perfusion studies

International Nuclear Information System (INIS)

DeLand, F.H.

1975-01-01

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

Dorsal Vagal Complex Modulates Neurogenic Airway Inflammation in a Guinea Pig Model With Esophageal Perfusion of HCl

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Zhe Chen

2018-05-01

Full Text Available Neurogenic airway inflammation in chronic cough and bronchial asthma related to gastroesophageal reflux (GER is involved in the esophageal–bronchial reflex, but it is unclear whether this reflex is mediated by central neurons. This study aimed to investigate the regulatory effects of the dorsal vagal complex (DVC on airway inflammation induced by the esophageal perfusion of hydrochloric acid (HCl following the microinjection of nuclei in the DVC in guinea pigs. Airway inflammation was evaluated by measuring the extravasation of Evans blue dye (EBD and substance P (SP expression in the airway. Neuronal activity was indicated by Fos expression in the DVC. The neural pathways from the lower esophagus to the DVC and the DVC to the airway were identified using DiI tracing and pseudorabies virus Bartha (PRV-Bartha retrograde tracing, respectively. HCl perfusion significantly increased plasma extravasation, SP expression in the trachea, and the expression of SP and Fos in the medulla oblongata nuclei, including the nucleus of the solitary tract (NTS and the dorsal motor nucleus of the vagus (DMV. The microinjection of glutamic acid (Glu or exogenous SP to enhance neuronal activity in the DVC significantly potentiated plasma extravasation and SP release induced by intra-esophageal perfusion. The microinjection of γ-aminobutyric acid (GABA, lidocaine to inhibit neuronal activity or anti-SP serum in the DVC alleviated plasma extravasation and SP release. In conclusion, airway inflammation induced by the esophageal perfusion of HCl is regulated by DVC. This study provides new insight for the mechanism of airway neurogenic inflammation related to GER.

Dynamic perfusion CT: Optimizing the temporal resolution for the calculation of perfusion CT parameters in stroke patients

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Kaemena, Andreas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)], E-mail: andreas.kaemena@charite.de; Streitparth, Florian; Grieser, Christian; Lehmkuhl, Lukas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany); Jamil, Basil [Department of Radiotherapy, Charite-Medical University Berlin, Schumannstr. 20/21, D-10117 Berlin (Germany); Wojtal, Katarzyna; Ricke, Jens; Pech, Maciej [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)

2007-10-15

Purpose: To assess the influence of different temporal sampling rates on the accuracy of the results from cerebral perfusion CTs in patients with an acute ischemic stroke. Material and methods: Thirty consecutive patients with acute stroke symptoms received a dynamic perfusion CT (LightSpeed 16, GE). Forty millilitres of iomeprol (Imeron 400) were administered at an injection rate of 4 ml/s. After a scan delay of 7 s, two adjacent 10 mm slices at 80 kV and 190 mA were acquired in a cine mode technique with a cine duration of 49 s. Parametric maps for the blood flow (BF), blood volume (BV) and mean transit time (MTT) were calculated for temporal sampling intervals of 0.5, 1, 2, 3 and 4 s using GE's Perfusion 3 software package. In addition to the quantitative ROI data analysis, a visual perfusion map analysis was performed. Results: The perfusion analysis proved to be technically feasible with all patients. The calculated perfusion values revealed significant differences with regard to the BF, BV and MTT, depending on the employed temporal resolution. The perfusion contrast between ischemic lesions and healthy brain tissue decreased continuously at the lower temporal resolutions. The visual analysis revealed that ischemic lesions were best depicted with sampling intervals of 0.5 and 1 s. Conclusion: We recommend a temporal scan resolution of two images per second for the best detection and depiction of ischemic areas.

The Hepatoprotective Effects of Corn Silk against Dose-induced Injury of Ecstasy (MDMA Using Isolated Rat Liver Perfusion System

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Mohammad Karami

2016-07-01

Full Text Available Background: Corn silk (CS is widely used in Iranian traditional medicine. The aim of this study was to investigate hepatoprotective activity of CS by Isolated Rat Liver Perfusion System (IRLP. Methods: Hydro-alcoholic extract of corn silk (10, 20, 40, and 100 mg kg-1 was evaluated for its hepatoprotective activity by IRLP. Phenol and flavonoid contents of the extract were determined as gallic acid and quercetin equivalents from a calibration curve, respectively. IRLP system is ideal for studying biochemical alterations of chemicals with minimum neuro-hormonal effects. In this study, the liver was perfused with Kerbs-Henseleit buffer, containing different concentration of hydro-alcoholic extract of corn silk (10, 20, 40, 50,100mg/kg, added to the buffer, and perfused for 2 hours. During the perfusion, many factors, including amino-transferees activities and the level of GSH, were assessed as indicators of liver viability. Consequently, sections of liver tissues were examined for any histopathological changes. Results: Histopathological changes in liver tissues were related to hydro-alcoholic extract of corn silk concentrations in a dose-dependent manner. Also, 50 and 100mg/kg doses caused significant (P<0.05 histopathological changes. Level of GSH in samples perfused with hydro-alcoholic extract increased compared to the control group. Conclusion: Hepatoprotective effect of CS is due to decreased lipid peroxidation, although other mechanisms might also be involved.

Time and dose-related changes in lung perfusion after definitive radiotherapy for NSCLC

DEFF Research Database (Denmark)

Farr, Katherina P; Khalil, Azza A; Møller, Ditte S

2018-01-01

BACKGROUND AND PURPOSE: To examine radiation-induced changes in regional lung perfusion per dose level in 58 non-small-cell lung cancer (NSCLC) patients treated with intensity-modulated radiotherapy (IMRT). MATERIAL AND METHODS: NSCLC patients receiving chemo-radiotherapy (RT) of minimum 60 Gy we...

Characteristics of Brain Perfusion in Patients of Parkinson's Disease

International Nuclear Information System (INIS)

Jeong, Young Jin; Park, Min Jung; Kim, Jae Woo; Kang, Young Kang

2008-01-01

It was well known that cerebral blood perfusion is normal or diffusely decreased in the majority of patients with Parkinson's disease (PD). Actually we interpreted brain perfusion SPECT images of PD patients in the clinical situation, we observed various cerebral perfusion patterns in patients with PD. So we performed brain perfusion SPECT to know the brain perfusion patterns of PD patients and the difference of perfusion patterns according to the sex and the age. Also we classified PD patients into small groups based on the brain perfusion pattern. Two hundred nineteen patients (M: 70, F: 149, mean age: 62.9±6.9 y/o) who were diagnosed as PD without dementia clinically and 55 patients (M: 15, F: 40, mean age: 61.4±9.2 y/o) as normal controls who had no past illness history were performed 99m Tc-HMPAO brain perfusion SPECT and neuropsychological test. At first, we compared all patients with PD and normal controls. Brain perfusion in left inferior frontal gyrus, left insula, left transverse temporal gyrus, left inferior parietal lobule, left superior parietal lobule, right precuneus, right caudate tail were lower in patients with PD than normal controls. Secondly, we compared male and female patients with PD and normal controls, respectively. Brain perfusion SPECT showed more decreased cerebral perfusion in left hemisphere than right side in both male and female patients compared to normal controls. And there was larger hypoperfusion area in female patients compared with male. Thirdly, we classified patients with PD and normal controls into 4 groups according to the age and compared brain perfusion respectively. In patient below fifties, brain perfusion in both occipitoparietal and left temporal lobe were lower in PD group. As the patients with PD grew older, hypoperfusion area were shown in both frontal, temporal and limbic lobes. Fourthly, We were able to divide patients into small groups based on cerebral perfusion pattern. There was normal cerebral blood

Regional Cerebral Perfusion in Progressive Supranuclear Palsy

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Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1996-03-15

Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

Low dose transdermal estradiol induces breast density and heterogeneity changes comparable to those of raloxifene

DEFF Research Database (Denmark)

Nielsen, Mads; Raundahl, Jakob; Pettersen, Paola

2009-01-01

Objective: To investigate whether transdermal low dose estradiol treatment induces changes in mammographic density or heterogeneity compared to raloxifene. Secondarily, if these changes relate to changes in bone formation/resorption markers, and if these findings indicate elevation of breast canc...

Thallium - 201 miocardial perfusion scintigraphy in patients with mitral valve prolapse, with and without coronary artery disease

International Nuclear Information System (INIS)

Moraes, A.G. de; Sousa, J.E.M.R.; Thom, A.F.; Martins, L.R.F.; Meneghelo, R.S.; Pimentel Filho, W.A.; Marioni Filho, H.; Gimenes, V.M.L.; Pontes Junior, S.C.

1981-01-01

Thirty patients with precordial pain and mitral valve prolapse diagnosed by cineangiography and M-mode echocardiography were submitted to Thallium-201 myocardial stress perfusion scintillography. They were divided into two groups: group I - eighteen patients with mitral valve prolapse and normal coronary arteries, of which ten presented positive exercise stress test (55.6%); eight patients had a negative exercise test. Thallium-201 myocardial stress perfusion scintillagraphy was normal in 14 (77.8%) patients, and four with positive stress perfursion scintillography, (three with inferior perfusion defects and one with a lateral one); group II - twelve patients with mitral valve prolapse and severe coronary artery disease (stenosis >= 60% in at least one main vessel of the coronary circulation), of which nine presented positive exercise stress test (75%) and three negative. Thallium-201 exercise myocardial perfusion scintillography was abnormal in nine (75%), six with stress induced ischemia and three with resting defect. Myocardial perfusion scintillography with Thallium-201 was more sensitive to detect the presence of coronary artery disease in patients with mitral valve prolapse (MVP) than the exercise stress test in spite of the fact that a small number of patients (22%) with MVP and normal coronary arteries exhibited abnormal myocardial stress perfusion during scintillography. (Author) [pt

Regional Cerebral Perfusion in Progressive Supranuclear Palsy

International Nuclear Information System (INIS)

Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S.; Lee, Kyung Han; Lee, Myung Chul

1996-01-01

Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p 0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

Computerized analysis of brain perfusion parameter images

International Nuclear Information System (INIS)

Turowski, B.; Haenggi, D.; Wittsack, H.J.; Beck, A.; Aurich, V.

2007-01-01

Purpose: The development of a computerized method which allows a direct quantitative comparison of perfusion parameters. The display should allow a clear direct comparison of brain perfusion parameters in different vascular territories and over the course of time. The analysis is intended to be the basis for further evaluation of cerebral vasospasm after subarachnoid hemorrhage (SAH). The method should permit early diagnosis of cerebral vasospasm. Materials and Methods: The Angiotux 2D-ECCET software was developed with a close cooperation between computer scientists and clinicians. Starting from parameter images of brain perfusion, the cortex was marked, segmented and assigned to definite vascular territories. The underlying values were averages for each segment and were displayed in a graph. If a follow-up was available, the mean values of the perfusion parameters were displayed in relation to time. The method was developed under consideration of CT perfusion values but is applicable for other methods of perfusion imaging. Results: Computerized analysis of brain perfusion parameter images allows an immediate comparison of these parameters and follow-up of mean values in a clear and concise manner. Values are related to definite vascular territories. The tabular output facilitates further statistic evaluations. The computerized analysis is precisely reproducible, i. e., repetitions result in exactly the same output. (orig.)

Dissociation of brain edema induced by cold injury in rat model. MR imaging and perfusion studies with 14C-iodo-antipyrine

International Nuclear Information System (INIS)

Itabashi, Yoko; Prado, G.L.M.; Abo, Mitsuru; Miura, Hiroyuki; Abe, Yoshinao

2001-01-01

The purpose of this study is to confirm whether T2-weighted imaging and perfusion imaging, i.e. autoradiogram of 14 C-iodoantipyrine, on the course of brain edema correspond to each other or not. Cold injured rat brains were used as a model and were sequentially examined by both methods and compared with each other and with histological specimens. Special focus relies on the time changes in the lesions. High SI of T2-weighted images were observed and the percentages in the high SI area to the total brain area in the same slice were 4.7±0.31, 5.6±0.46 and 3.4±0.42 for 6, 24 and 48 hours, respectively. By contrast, low perfusion areas were indicated in the perfusion study and their percentages were 4.6±0.55, 5.6±0.86 and 2.4±0.35 for 6, 24 and 48 hours, respectively. At 48 hours after cold injury, low perfusion areas were smaller than high SI areas. Moreover, high accumulation areas consisting of macrophages were observed surrounding necrosis. It is concluded that there is dissociation between perfusion and T2-weighted MR imaging, where the collection of macrophages surrounding edema lesions and necrosis had the same appearance on MRI and different accumulations on perfusion studies. (author)

Effects of isosorbide dinitrate on exertion-induced anomalous myocardial perfusion in coronary diseases studied with the aid of 201Th scintiscanning

International Nuclear Information System (INIS)

Wolf, R.; Pretschner, P.; Engel, H.J.; Hundeshagen, H.; Lichtlen, P.R.; Medizinische Hochschule Hannover

1979-01-01

The effect of isosorbide dinitrate (ISDN) (10 mg sublingually) on myocardial perfusion under ischemic conditions was analyzed in 14 patients with angiographically severe coronary artery disease and typical angina pectoris, using 201-thallium-myocardial scintiscanning. All patients underwent two identical scintiscans with the same work load during bicycle ergometry; a control scintiscan leading to angina and ST-depressions of > 0.1 mV was followed 4-6 weeks later by a scintiscan after ISDN; all drugs - except sublingual nitroglycerin - were withheld for an entire week. - Results: 25 of 39 new or enlarged, exercise-induced defects (64%) were normalized after ISDN; 14 new or enlarged defects remained unchanged (p [de

Functional Mechanism of Lung Mosaic CT Attenuation: Assessment with Deep-Inspiration Breath-Hold Perfusion SPECT-CT Fusion Imaging and Non-Breath-Hold Technegas SPECT

International Nuclear Information System (INIS)

Suga, K.; Yasuhiko, K.; Iwanaga, H.; Tokuda, O.; Matsunaga, N.

2009-01-01

required, our results indicate that heterogeneous pulmonary arterial perfusion may be a dominant mechanism of MCA in PVD and OAD

Functional Mechanism of Lung Mosaic CT Attenuation: Assessment with Deep-Inspiration Breath-Hold Perfusion SPECT-CT Fusion Imaging and Non-Breath-Hold Technegas SPECT

Energy Technology Data Exchange (ETDEWEB)

Suga, K.; Yasuhiko, K. (Dept. of Radiology, St. Hill Hospital, Ube, Yamaguchi (Japan)); Iwanaga, H.; Tokuda, O.; Matsunaga, N. (Dept. of Radiology, Yamaguchi Univ. School of Medicine, Ube, Yamaguchi (Japan))

2009-01-15

required, our results indicate that heterogeneous pulmonary arterial perfusion may be a dominant mechanism of MCA in PVD and OAD

Functional mechanism of lung mosaic CT attenuation: assessment with deep-inspiration breath-hold perfusion SPECT-CT fusion imaging and non-breath-hold Technegas SPECT.

Science.gov (United States)

Suga, K; Yasuhiko, K; Iwanaga, H; Tokuda, O; Matsunaga, N

2009-01-01

The functional mechanism of lung mosaic computed tomography attenuation (MCA) in pulmonary vascular disease (PVD) and obstructive airway disease (OAD) has not yet been fully clarified. To clarify the mechanism of MCA in these diseases by assessing the relationship between regional lung function and CT attenuation change at MCA sites with the use of automated deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images and non-breath-hold Technegas SPECT. Subjects were 42 PVD patients (31 pulmonary thromboembolism, four primary/two secondary pulmonary hypertension, and five Takayasu arteritis), 12 OAD patients (five acute asthma, four obliterative bronchiolitis, and three bronchiectasis), and 12 normal controls, all of whom had MCA on DIBrH CT. The relationship between regional lung function and CT attenuation change at the lung slices with MCA was assessed using DIBrH perfusion SPECT-CT fusion images and non-breath-hold Technegas SPECT. The severity of perfusion defects with or without MCA was quantified by regions-of-interest analysis. On DIBrH CT and perfusion SPECT, in contrast to no noticeable CT attenuation abnormality and fairly uniform perfusion in controls, 60 MCA and 274 perfusion defects in PVD patients, and 18 MCA and 61 defects in OAD patients were identified, with a total of 77 ventilation defects on Technegas SPECT in all patients. SPECT-CT correlation showed that, throughout the 78 MCA sites of all patients, lung perfusion was persistently decreased at low CT attenuation and preserved at intervening high CT attenuation, while lung ventilation was poorly correlated with CT attenuation change. The radioactivity ratios of reduced perfusion and the intervening preserved perfusion at the 78 perfusion defects with MCA were significantly lower than those at the remaining 257 defects without MCA (P<0.0001). Although further validation is required, our results indicate that heterogeneous pulmonary arterial

Compartmented pyruvate in perfused working heart

International Nuclear Information System (INIS)

Buenger, R.

1985-01-01

Pyruvate compartmentation and lactate dehydrogenase (LDH) were studied in isolated perfused working guinea pig hearts. The mean intracellular pyruvate (Pyr) contents increased with perfusate Pyr (0-2 mM) but varied only slightly with glucose (0-10 mM) and additional insulin (0.04-5 U/l), respectively. With 5-10 mM glucose plus 5 U/l insulin, but not with Pyr or lactate (Lac) as substrates, a near equilibrium between the LDH and the glycerol-3-phosphate dehydrogenase seemed to exist. Evidence for an inhibitory effect of Pyr on the activity of the LDH system of the perfused hearts was not obtained. With [U- 14 C]glucose as sole substrate, the specific activity of coronary venous Lac was near half that of precursor glucose. 14 CO 2 production was thus in quantitative agreement with rates of pyruvate oxidation that were determined as glucose uptake minus (Pyr + Lac) release. In contrast, with 0.2 mM [1- 14 C]Pyr plus 5 mM glucose, the ratio of 14 CO 2 production to specific activity of Lac overestimated Pyr oxidation judged from myocardial substrate balances and O 2 uptake, respectively; here, at least three pools of [ 14 C]HCO-3 and [ 14 C]lac, respectively, were kinetically demonstrable during washout of trace amounts of 14 C-labeled Pyr. Evidently, the specific activity of Lac was equivalent to that of mitochondrial oxidized Pyr provided [ 14 C]glucose was the sole or major precursor of cellular pyruvate. However, exogenously applied [1- 14 C]Pyr of high specific activity seemed to induce intracellular formation of both a highly and lowly labeled Pyr; the latter Pyr compartment did not seem in ready equilibrium with the cell physiologically prevailing highly labeled Pyr pool

Extracellular Vesicles from Human Liver Stem Cells Reduce Injury in an Ex Vivo Normothermic Hypoxic Rat Liver Perfusion Model.

Science.gov (United States)

Rigo, Federica; De Stefano, Nicola; Navarro-Tableros, Victor; David, Ezio; Rizza, Giorgia; Catalano, Giorgia; Gilbo, Nicholas; Maione, Francesca; Gonella, Federica; Roggio, Dorotea; Martini, Silvia; Patrono, Damiano; Salizzoni, Mauro; Camussi, Giovanni; Romagnoli, Renato

2018-05-01

The gold standard for organ preservation before transplantation is static cold storage, which is unable to fully protect suboptimal livers from ischemia/reperfusion injury. An emerging alternative is normothermic machine perfusion (NMP), which permits organ reconditioning. Here, we aimed to explore the feasibility of a pharmacological intervention on isolated rat livers by using a combination of NMP and human liver stem cells-derived extracellular vesicles (HLSC-EV). We established an ex vivo murine model of NMP capable to maintain liver function despite an ongoing hypoxic injury induced by hemodilution. Livers were perfused for 4 hours without (control group, n = 10) or with HLSC-EV (treated group, n = 9). Bile production was quantified; perfusate samples were collected hourly to measure metabolic (pH, pO2, pCO2) and cytolysis parameters (AST, alanine aminotransferase, lactate dehydrogenase). At the end of perfusion, we assessed HLSC-EV engraftment by immunofluorescence, tissue injury by histology, apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, tissue hypoxia-inducible factor 1-α, and transforming growth factor-beta 1 RNA expression by quantitative reverse transcription-polymerase chain reaction. During hypoxic NMP, livers were able to maintain homeostasis and produce bile. In the treated group, AST (P = 0.018) and lactate dehydrogenase (P = 0.032) levels were significantly lower than those of the control group at 3 hours of perfusion, and AST levels persisted lower at 4 hours (P = 0.003). By the end of NMP, HLSC-EV had been uptaken by hepatocytes, and EV treatment significantly reduced histological damage (P = 0.030), apoptosis (P = 0.049), and RNA overexpression of hypoxia-inducible factor 1-α (P < 0.0001) and transforming growth factor-beta 1 (P = 0.014). HLSC-EV treatment, even in a short-duration model, was feasible and effectively reduced liver injury during hypoxic NMP.

Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

Energy Technology Data Exchange (ETDEWEB)

Ogami, M; Kulkarni, R; Wang, H; Reif, R; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

2014-08-31

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)

Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

Science.gov (United States)

Ogami, M.; Kulkarni, R.; Wang, H.; Reif, R.; Wang, R. K.

2014-08-01

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing.

Comparison with myocardial perfusion MRI and myocardial perfusion SPECT in the diagnostic performance of coronary artery disease. A meta-analysis

International Nuclear Information System (INIS)

Iwata, Kunihiro; Kubota, Makoto; Ogasawara, Katsuhiko

2008-01-01

We compared the diagnostic abilities of stress myocardial perfusion MRI (myocardial perfusion MRI) and myocardial perfusion single photon emission computed tomography (SPECT), using a meta-analysis method. We investigated the diagnostic abilities of MRI and SPECT in similar subject groups in reports written in English or Japanese. The reports to be used for analysis were selected according to a ''screening standard,'' which was established in advance. After consolidating the data from the selected reports, we compared the integrated odds ratio, the point estimation values of sensibility/specificity, and the summary receiver operating characteristic (ROC) curve. For the analysis, six reports were selected (subjects: 153, coronary-artery target sites: 447). Meta-analysis revealed that the diagnostic ability of myocardial perfusion MRI was superior to that of myocardial perfusion SPECT regarding each of the parameters. This is considered to be supportive evidence of the usefulness of myocardial perfusion MRI. (author)

Heterogeneity effects in neutron transport computations

International Nuclear Information System (INIS)

Gelbard, E.M.

1975-01-01

A nuclear reactor is, generally, an intricate heterogeneous structure whose adjacent components may differ radically in their neutronic properties. The heterogeneities in the structure of the reactor complicate the work of the reactor analyst and tend to degrade the efficiency of the numerical methods used in reactor computations. Two types of heterogeneity effects are considered. First, certain singularities in the solution of the neutron transport equation, induced by heterogeneities, are briefly described. Second, the effect of heterogeneities on neutron leakage rates, and consequently on effective diffusion coefficients, are discussed. (5 figures) (U.S.)

Tc-99m DTPA perfusion scintigraphy and color coded duplex sonography in the evaluation of minimal renal allograft perfusion

International Nuclear Information System (INIS)

Bair, H.J.; Platsch, G.; Wolf, F.; Guenter, E.; Becker, D.; Rupprecht, H.; Neumayer, H.H.

1997-01-01

Aim: The clinical impact of perfusion scintigraphy versus color coded Duplex sonography was evaluated, with respect to their potential in assessing minimal allograft perfusion in vitally threatened kidney transplants, i.e. oligoanuric allografts suspected to have either severe rejection or thrombosis of the renal vein or artery. Methods: From July 1990 to August 1994 the grafts of 15 out of a total of 315 patients were vitally threatened. Technetium-99m DTPA scintigraphy and color coded Duplex sonography were performed in all patients. For scintigraphic evaluation of transplant perfusion analog scans up to 60 min postinjection, and time-activity curves over the first 60 sec after injection of 370-440 MBq Tc-99m diethylenetriaminepentaacetate acid (DTPA) were used and classified by a perfusion score, the time between renal and iliac artery peaks (TDiff) and the washout of the renogram curve. Additionally, evaluation of excretion function and assessment of vascular or urinary leaks were performed. By color coded Duplex sonography the perfusion in all sections of the graft as well as the vascular anastomoses were examined and the maximal blood flow velocity (Vmax) and the resistive index (RI) in the renal artery were determined by means of the pulsed Doppler device. Pathologic-anatomical diagnosis was achieved by either biopsy or post-explant histology in all grafts. Results: Scintigraphy and color coded Duplex sonography could reliably differentiate minimal (8/15) and not perfused (7/15) renal allografts. The results were confirmed either by angiography in digital subtraction technique (DSA) or the clinical follow up. Conclusion: In summary, perfusion scintigraphy and color coded Duplex sonography are comparable modalities to assess kidney graft perfusion. In clinical practice scintigraphy and colorcoded Doppler sonography can replace digital subtraction angiography in the evaluation of minimal allograft perfusion. (orig.) [de

Normal anatomy of lung perfusion SPECT scintigraphy

International Nuclear Information System (INIS)

Moskowitz, G.W.; Levy, L.M.

1987-01-01

Ten patients studies for possible pulmonary embolic disease had normal lung perfusion planar and SPECT scintigraphy. A computer program was developed to superimpose the CT scans on corresponding SPECT images. Superimposition of CT scans on corresponding SPECT transaxial cross-sectional images, when available, provides the needed definition and relationships of adjacent organs. SPECT transaxial sections provide clear anatomic definition of perfusion defects without foreground and background lung tissue superimposed. The location, shape, and size of the perfusion defects can be readily assessed by SPECT. An algorithm was developed for the differentiation of abnormal pulmonary perfusion patterns from normal structures on variation

Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

Directory of Open Access Journals (Sweden)

Schudt Christian

2005-07-01

Full Text Available Abstract Background The sources and measurement of reactive oxygen species (ROS in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %, the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to

Regional cortical hyper perfusion on perfusion CT during postical motor deficit: A case report

Energy Technology Data Exchange (ETDEWEB)

Baik, Hye Jin [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

2013-08-15

Postictal neurologic deficit is a well-known complication mimicking the manifestation of a stroke. We present a case of a patient with clinical evidence of Todd's paralysis correlating with reversible postictal parenchymal changes on perfusion CT and magnetic resonance (MR) imaging. In this case, perfusion CT and MR imaging were helpful in the differential diagnosis of stroke-mimicking conditions.

Ventilation and perfusion display in a single image

International Nuclear Information System (INIS)

Lima, J.J.P. de; Botelho, M.F.R.; Pereira, A.M.S.; Rafael, J.A.S.; Pinto, A.J.; Marques, M.A.T.; Pereira, M.C.; Baganha, M.F.; Godinho, F.

1991-01-01

A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms. (orig.)

High-resolution MRI for the quantitative evaluation of subendocardial and subepicardial perfusion under pharmalogical stress and at rest

International Nuclear Information System (INIS)

Ritter, C.O.; Savio, K. del; Brackertz, A.; Beer, M.; Hahn, D.; Koestler, H.

2007-01-01

Purpose: MR stress perfusion imaging of the heart allows the quantification of myocardial perfusion and the evaluation of myocardial perfusion reserve (MPR) and the ratio of subendocardial to subepicardial perfusion at rest and under adenosine stress. The aim of this study was to evaluate a high-resolution GRAPPA sequence for quantitative MR first pass perfusion imaging in healthy volunteers. Materials and Methods: First pass stress and rest perfusion studies were performed on 10 healthy volunteers using a 1.5 T MR scanner with a multislice SR-TrueFISP first pass perfusion sequence with a GRAPPA algorithm (acceleration factor 3) in prebolus technique and an image resolution of 1.8 x 1.8 mm. For the comparison group, we examined 12 different healthy volunteers with a standard first pass perfusion SR-TrueFISP sequence using a resolution of 2.7 x 3.3 mm. Myocardial contours were manually delineated followed by an automatic division of the myocardium into two rings with an equal thickness for the subendo- and subepicardial layer. Eight sectors per slice were evaluated using contamination and baseline correction. Results: Using the GRAPPA sequence, the ratio of subendo- to subepimyocardial perfusion was 1.18 ± 0.32 for the examination at rest. Under pharmacologically induced stress, the ratio was 1.08 ± 0.27. For the standard sequence the ratio was 1.15 ± 0.28 at rest and 1.11 ± 0.33 under stress. For the high resolution sequence higher mean values for the subendo- to subepimyocardial ratio were obtained with comparable standard deviations. The difference between the sequences was not significant. Conclusion: The evaluation of subendomyocardial and subepimyocardial perfusion is feasible with a high-resolution first pass perfusion sequence. The use of a higher resolution to avoid systematic error leads to increased image noise. However, no relevant reduction in the quantitative perfusion values under stress and at rest was able to be depicted. (orig.)

Contractile responses to ergotamine and dihydroergotamine in the perfused middle cerebral artery of rat

DEFF Research Database (Denmark)

Tfelt-Hansen, Peer; Nilsson, Elisabeth; Edvinsson, Lars

2007-01-01

mmHg and luminally perfused. All vessels used attained spontaneous contractile tone (34.9+/-1.8% of resting tone) and responded to luminal adenosine triphosphate (ATP) with dilatation (24.1+/-4.0%), which showed functioning endothelium. Luminally added ergotamine or DHE induced maximal contractions...

Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion.

Directory of Open Access Journals (Sweden)

Carmen Ghisleni

Full Text Available Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women. Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women.

Assessing the scale of tumor heterogeneity by complete hierarchical segmentation of MRI.

Science.gov (United States)

Gensheimer, Michael F; Hawkins, Douglas S; Ermoian, Ralph P; Trister, Andrew D

2015-02-07

In many cancers, intratumoral heterogeneity has been found in histology, genetic variation and vascular structure. We developed an algorithm to interrogate different scales of heterogeneity using clinical imaging. We hypothesize that heterogeneity of perfusion at coarse scale may correlate with treatment resistance and propensity for disease recurrence. The algorithm recursively segments the tumor image into increasingly smaller regions. Each dividing line is chosen so as to maximize signal intensity difference between the two regions. This process continues until the tumor has been divided into single voxels, resulting in segments at multiple scales. For each scale, heterogeneity is measured by comparing each segmented region to the adjacent region and calculating the difference in signal intensity histograms. Using digital phantom images, we showed that the algorithm is robust to image artifacts and various tumor shapes. We then measured the primary tumor scales of contrast enhancement heterogeneity in MRI of 18 rhabdomyosarcoma patients. Using Cox proportional hazards regression, we explored the influence of heterogeneity parameters on relapse-free survival. Coarser scale of maximum signal intensity heterogeneity was prognostic of shorter survival (p = 0.05). By contrast, two fractal parameters and three Haralick texture features were not prognostic. In summary, our algorithm produces a biologically motivated segmentation of tumor regions and reports the amount of heterogeneity at various distance scales. If validated on a larger dataset, this prognostic imaging biomarker could be useful to identify patients at higher risk for recurrence and candidates for alternative treatment.

CT perfusion of the liver during selective hepatic arteriography. Pure arterial blood perfusion of liver tumor and parenchyma

International Nuclear Information System (INIS)

Komemushi, Atsushi; Tanigawa, Noboru; Kojima, Hiroyuki; Kariya, Shuji; Sawada, Satoshi

2003-01-01

The purpose of this study was to quantify pure arterial blood perfusion of liver tumor and parenchyma by using CT perfusion during selective hepatic arteriography. A total of 44 patients underwent liver CT perfusion study by injection of contrast medium via the hepatic artery. CT-perfusion parameters including arterial blood flow, arterial blood volume, and arterial mean transit time in the liver parenchyma and liver tumor were calculated using the deconvolution method. The CT-perfusion parameters and vascularity of the tumor were compared. A complete analysis could be performed in 36 of the 44 patients. For liver tumor and liver parenchyma, respectively, arterial blood flow was 184.6±132.7 and 41.0±27.0 ml/min/100 g, arterial blood volume was 19.4±14.6 and 4.8±4.2 ml/100 g, and arterial mean transit time was 8.9±4.2 and 10.2±5.3 sec. Arterial blood flow and arterial blood volume correlated significantly with the vascularity of the tumor; however no correlation was detected between arterial mean transit time and the vascularity of the tumor. This technique could be used to quantify pure hepatic arterial blood perfusion. (author)

Quantitative perfusion imaging in magnetic resonance imaging

International Nuclear Information System (INIS)

Zoellner, F.G.; Gaa, T.; Zimmer, F.; Ong, M.M.; Riffel, P.; Hausmann, D.; Schoenberg, S.O.; Weis, M.

2016-01-01

Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.) [de

Perfusion-weighted MR imaging of uterine leiomyoma

Energy Technology Data Exchange (ETDEWEB)

Takase, Hiroyasu; Munechika, Hirotsugu [Showa Univ., Tokyo (Japan). School of Medicine

2001-06-01

Serial images of uterine leiomyoma in gradient-echo, echo-planar, magnetic resonance imaging were taken to draw a {delta}R2{sup *} curve after intravenous bolus injection of Gd-DTPA. The {delta}R2{sup *} integral was calculated from a {delta}R2{sup *} curve to have relative perfusion of uterine leiomyoma. We then, evaluated the amount of perfusion correlated with MR findings, size and number of leiomyoma or the clinical symptoms and established that perfusion was correlated positively with the findings of T2 weighted images and clinical symptoms but not with other MR findings or size and number of leiomyoma. In conclusion, we presumed that the clinical symptoms could be reduced by decreasing of an amount of perfusion of uterine leiomyoma in some means. However, it remained uncertain why severe clinical symptoms were associated with a high amount of perfusion in uterine leiomyomas. (author)

Relations between CT perfusion parameters and degree of hepatic ischemia reperfusion injury in a rabbit model

International Nuclear Information System (INIS)

Guo Chengwei; Shen Sandi; Yi Xianlin; Zhang Zhonglin; Liu Zaiyi; Liang Changhong

2011-01-01

Objective: To observe the changes of hepatic CT perfusion parameters and their correlation with serum aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) in a rabbit hepatic ischemia reperfusion injury (IRI) model. Methods: Hepatic IRI was produced in rabbits by inducing left liver lobe ischemia (60 min) followed by 6 h, 12 h and 24 h reperfusion (6 rabbits were used for each reperfusion interval). Additional 6 rabbits were served as sham-operated controls. All the rabbits were scanned with a dynamic iCT protocol. Blood samples were taken from the superior mesenteric vein to measure the levels of serum amylase (ALT, AST, and ALP) in various groups, and liver samples were taken for histological examinations after scanning. One-way analysis of variance (ANOVA) was used to determine differences between groups. The correlations of CT perfusion parameters with serum levels were analyzed using Pearson correlation coefficient. Results: Heterogeneity of CT perfusion patterns appeared in the 6 h groups, which presented as low enhanced area [(25.1±9.3) ml · min -1 · 100 mg -1 ]. In reduced perfusion regions of IRI group, HAP of 12 h IRI group [(19.5± 13.6) ml · min -1 · 100 mg -1 ], 24 h IRI group (8.0±2.7) ml · min -1 · 100 mg -1 ], HPP of 6 h IRI group [(10.8±5.5) ml · min -1 · 100 mg -1 ], 12 h IRI group [(14.4±5.2) ml · min -1 · 100 mg -1 ] , 24 h IRI group [(7.8±3.3) ml · min -1 · 100 mg -1 ] and TLP of 6 h IRI group [(35.9±14.0) ml · min -1 · 100 mg -1 ], 12 h IRI group [(33.9±16.1) ml · min -1 · 100 mg -1 ], 24 h IRI group [(16.0± 5.5) ml · min -1 · 100 mg -1 ] were lower than those of sham group [HAP (21.2±10.5) ml · min -1 · 100 mg -1 , HPP (63.5±24.0) ml · min -1 · 100 mg -1 , TLP (81.4±24.8) ml · min -1 · 100 mg -1 ] (F=8.376, 25.950, 16.925, P<0.01). However, HPI of 6 h IRI group [(65.9±3.9)%], 12 h IRI group [(54.2±16.7)%], and 24 h IRI group [(48.9±10.0)%] were higher compared to sham

Thallium-201 exercise myocardial imaging to evaluate myocardial perfusion after coronary artery bypass surgery

International Nuclear Information System (INIS)

Hirzel, H.O.; Nuesch, K.; Sialer, G.; Horst, W.; Krayenbuehl, H.P.

1980-01-01

To assess the usefulness of thallium-201 exercise scintigraphy in evaluating myocardial perfusion after coronary artery bypass surgery, imaging was performed after submaximal bicycle ergometry and at rest in 54 patients before and within 24 +- 10 (SD) weeks after operation. Scintigraphy identified 8 out of 20 patients who were symptom free after operation and showed normal exercise electrocardiograms as still having exercise-induced ischaemia and thus as having not truly benefited from the surgical intervention. In contrast, improvement in perfusion was documented in 17 out of 31 patients despite further complaints of chest pain and persistence of a pathological exercise electrocardiogram in 6 of them. Bypass graft patency rate paralleled the scintigraphic findings in the 35 patients who were restudied arteriographically. It was concluded that thallium-201 exercise scintigraphy is a useful technique to document changes in regional perfusion after surgery and is definitely superior to the clinical evaluation of patients including the exercise electrocardiogram. (author)

Regional myocardial perfusion of cardioplegic solutions

International Nuclear Information System (INIS)

Eugene, J.; Lyons, K.P.; Ott, R.A.; Gelezunas, V.L.; Chang, C.W.; Kowall, M.G.; Haiduc, N.J.

1987-01-01

We compared the regional myocardial perfusion of blood cardioplegic solution (BCP) and crystalloid cardioplegic solution (CCP) in 14 mongrel dogs. Cardiopulmonary bypass was established at 28 degrees C, and a hydraulic occluder was placed around the proximal left anterior descending (LAD) coronary artery. In group 1 (N = 7) collateral coronary arteries were ligated; in group 2 (N = 7) collateral coronary arteries were left in situ. After the aorta was clamped, BCP and CCP were alternately perfused at 200 ml/min. The occluder was inflated to produce moderate, severe, and critical LAD stenosis, and regional perfusion was measured by xenon-133 washout with the Silicon Avalanche Radiation Detector. BCP infusion produced a consistently higher aortic pressure, but CCP flow was better than BCP flow under all conditions, particularly without coronary collaterals. Regional myocardial perfusion of CCP is superior to BCP

Consideration of Normal Variation of Perfusion Measurements in the Quantitative Analysis of Myocardial Perfusion SPECT: Usefulness in Assessment of Viable Myocardium

International Nuclear Information System (INIS)

Paeng, Jin Chul; Lim, Il Han; Kim, Ki Bong; Lee, Dong Soo

2008-01-01

Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F=28:27) of low-likelihood for coronary artery disease were enrolled and 201 Tl rest / 99m Tc-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. 201 Tl rest / 99m Tc-MIBI stress / 201 Tl 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, Q delay (perfusion measurement), Δ delay (Q delay .m) and Z delay ((Q delay .m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was 51.8±6.5 and the highest segmental perfusion was 87.0±5.9, and they are 58.7±8.1 and 87.3±6.0, respectively in women. In the viability assessment, Q delay showed AUC of 0.633, while those for Δ delay and Z delay were 0.735 and 0.716, respectively. The AUCs of Δ delay and Z delay were significantly higher than that of Q delay (p=0.001 and 0.018, respectively). The diagnostic performance of Δ delay , which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. On automatic

Hepatic artery perfusion imaging

International Nuclear Information System (INIS)

Thrall, J.H.; Gyves, J.W.; Ziessman, H.A.; Ensminger, W.D.

1985-01-01

Organ and region-selective intra-arterial chemotherapy have been used for more than two decades to treat malignant neoplasms in the extremities, head and neck region, pelvis, liver, and other areas. Substantial evidence of improved response to regional chemotherapy now exists, but there are stringent requirements for successful application of the regional technique. First, the chemotherapeutic agent employed must have appropriate pharmacokinetic and pharmacodynamic properties. Second, the drug must be reliably delivered to the tumor-bearing area. This typically requires an arteriographic assessment of the vascular supply of the tumor, followed by placement of a therapeutic catheter and confirmation that the ''watershed'' perfusion distribution from the catheter truly encompasses the tumor. Optimal catheter placement also minimizes perfusion of nontarget organs. Radionuclide perfusion imaging with technetium 99m-labeled particles, either microspheres or macroaggregates of albumin, has become the method of choice for making these assessments. Catheter placement itself is considered by many to represent a type of ''therapeutic'' intervention. However, once the catheter is in the hepatic artery the radionuclide perfusion technique can be used to assess adjunctive pharmacologic maneuvers designed to further exploit the regional approach to chemotherapy. This chapter presents the technetium Tc 99m macroaggregated albumin method for assessing catheter placement and the pharmacokinetic rationale for regional chemotherapy, and discusses two promising avenues for further intervention

[An automatic system controlled by microcontroller for carotid sinus perfusion].

Science.gov (United States)

Yi, X L; Wang, M Y; Fan, Z Z; He, R R

2001-08-01

To establish a new method for controlling automatically the carotid perfusion pressure. A cheap practical automatic perfusion unit based on AT89C2051 micro controller was designed. The unit, LDB-M perfusion pump and the carotid sinus of an animal constituted an automatic perfusion system. This system was able to provide ramp and stepwise updown perfusion pattern and has been used in the research of baroreflex. It can insure the precision and reproducibility of perfusion pressure curve, and improve the technical level in corresponding medical field.

Cerebral effects of commonly used vasopressor-inotropes: a study in newborn piglets.

Directory of Open Access Journals (Sweden)

Gitte H Hahn

Full Text Available Despite widespread use in sick infants, it is still debated whether vasopressor-inotropes have direct cerebral effects that might affect neurological outcome. We aimed to test direct cerebrovascular effects of three commonly used vasopressor-inotropes (adrenaline, dopamine and noradrenaline by comparing the responses to those of nonpharmacologically induced increases in blood pressure. We also searched for reasons for a mismatch between the response in perfusion and oxygenation.Twenty-four piglets had long and short infusions of the three vasopressor-inotropes titrated to raise mean arterial blood pressure (MAP 10 mmHg in random order. Nonpharmacological increases in MAP were induced by inflation of a balloon in the descending aorta. We measured cerebral oxygenation (near-infrared spectroscopy, perfusion (laser-Doppler, oxygen consumption (co-oximetry of arterial and superior sagittal sinus blood, and microvascular heterogeneity (side stream dark field video microscopy.Vasopressor-inotropes increased cerebral oxygenation significantly less (p≤0.01 compared to non-pharmacological MAP increases, whereas perfusion was similar. Furthermore, cerebral total hemoglobin concentration increased significantly less during vasopressor-inotrope infusions (p = 0.001. These physiologic responses were identical between the three vasopressor-inotropes (p>0.05. Furthermore, they induced a mild, although insignificant increase in cerebral metabolism and microvascular heterogeneity (p>0.05. Removal of the scalp tissue did not influence the mismatch (p>0.05.We demonstrated a moderate vasopressor-inotrope induced mismatch between cerebral perfusion and oxygenation. Scalp removal did not affect this mismatch, why vasopressor-inotropes appear to have direct cerebral actions. The statistically nonsignificant increases in cerebral metabolism and/or microvascular heterogeneity may explain the mismatch. Alternatively, it may simply reflect a vasopressor-inotrope-induced

CT perfusion for determination of pharmacologically mediated blood flow changes in an animal tumor model.

Science.gov (United States)

Hakimé, Antoine; Peddi, Himaja; Hines-Peralta, Andrew U; Wilcox, Carol J; Kruskal, Jonathan; Lin, Shezhang; de Baere, Thierry; Raptopoulos, Vassilios D; Goldberg, S Nahum

2007-06-01

To prospectively compare single- and multisection computed tomographic (CT) perfusion for tumor blood flow determination in an animal model. All animal protocols and experiments were approved by the institutional animal care and use committee before the study was initiated. R3230 mammary adenocarcinoma was implanted in 11 rats. Tumors (18-20 mm) were scanned with dynamic 16-section CT at baseline and after administration of arsenic trioxide, which is known to cause acute reduction in blood flow. The concentration of arsenic was titrated (0-6 mg of arsenic per kilogram of body weight) to achieve a defined blood flow reduction (0%-75%) from baseline levels at 60 minutes, as determined with correlative laser Doppler flowmetry. The mean blood flow was calculated for each of four 5-mm sections that covered the entire tumor, as well as for the entire tumor after multiple sections were processed. Measurements obtained with both methods were correlated with laser Doppler flowmetry measurements. Interobserver agreement was determined for two blinded radiologists, who calculated the percentage of blood flow reduction for the "most representative" single sections at baseline and after arsenic administration. These results were compared with the interobserver variability of the same radiologists obtained by summing blood flow changes for the entire tumor volume. Overall correlations for acute blood flow reduction were demonstrated between laser Doppler flowmetry and the two CT perfusion approaches (single-section CT, r=0.85 and r(2)=0.73; multisection CT, r=0.93 and r(2)=0.87; pooled data, P=.01). CT perfusion disclosed marked heterogeneity of blood flow, with variations of 36% +/- 13 between adjacent 5-mm sections. Given these marked differences, interobserver agreement was much lower for single-section CT (standard deviation, 0.22) than for multisection CT (standard deviation, 0.10; P=.01). Multisection CT perfusion techniques may provide an accurate and more reproducible

Hypoxic treatment of human dual placental perfusion induces a preeclampsia-like inflammatory response.

Science.gov (United States)

Jain, Arjun; Schneider, Henning; Aliyev, Eldar; Soydemir, Fatimah; Baumann, Marc; Surbek, Daniel; Hediger, Matthias; Brownbill, Paul; Albrecht, Christiane

2014-08-01

Preeclampsia is a human pregnancy-specific disorder characterized by a placental pro-inflammatory response in combination with an imbalance of angiogenic factors and clinical symptoms, including hypertension and proteinuria. Insufficient uteroplacental oxygenation in preeclampsia due to impaired trophoblast invasion during placentation is believed to be responsible for many of the molecular events leading to the clinical manifestations of this disease. We investigated the use of hypoxic treatment of the dual placental perfusion system as a model for preeclampsia. A modified perfusion technique allowed us to achieve a mean soluble oxygen tension within the intervillous space (IVS) of 5-7% for normoxia and preeclampsia). We assayed for the levels of different inflammatory cytokines, oxidative stress markers, as well as other factors, such as endothelin (ET)-1 that are known to be implicated as part of the inflammatory response in preeclampsia. Our results show a significant increase under hypoxia in the levels of different inflammatory cytokines, including IL-6 (P=0.002), IL-8 (Ppreeclampsia. This would therefore provide a powerful tool for studying and further delineating the molecular mechanisms involved in the underlying pathophysiology of preeclampsia.

Fusion of CT coronary angiography and whole-heart dynamic 3D cardiac MR perfusion: building a framework for comprehensive cardiac imaging.

Science.gov (United States)

von Spiczak, Jochen; Manka, Robert; Gotschy, Alexander; Oebel, Sabrina; Kozerke, Sebastian; Hamada, Sandra; Alkadhi, Hatem

2018-04-01

The purpose of this work was to develop a framework for 3D fusion of CT coronary angiography (CTCA) and whole-heart dynamic 3D cardiac magnetic resonance perfusion (3D-CMR-Perf) image data-correlating coronary artery stenoses to stress-induced myocardial perfusion deficits for the assessment of coronary artery disease (CAD). Twenty-three patients who underwent CTCA and 3D-CMR-Perf for various indications were included retrospectively. For CTCA, image quality and coronary diameter stenoses > 50% were documented. For 3D-CMR-Perf, image quality and stress-induced perfusion deficits were noted. A software framework was developed to allow for 3D image fusion of both datasets. Computation steps included: (1) fully automated segmentation of coronary arteries and heart contours from CT; (2) manual segmentation of the left ventricle in 3D-CMR-Perf images; (3) semi-automatic co-registration of CT/CMR datasets; (4) projection of the 3D-CMR-Perf values on the CT left ventricle. 3D fusion analysis was compared to separate inspection of CTCA and 3D-CMR-Perf data. CT and CMR scans resulted in an image quality being rated as good to excellent (mean scores 3.5 ± 0.5 and 3.7 ± 0.4, respectively, scale 1-4). 3D-fusion was feasible in all 23 patients, and perfusion deficits could be correlated to culprit coronary lesions in all but one case (22/23 = 96%). Compared to separate analysis of CT and CMR data, coronary supply territories of 3D-CMR-Perf perfusion deficits were refined in two cases (2/23 = 9%), and the relevance of stenoses in CTCA was re-judged in four cases (4/23 = 17%). In conclusion, 3D fusion of CTCA/3D-CMR-Perf facilitates anatomic correlation of coronary lesions and stress-induced myocardial perfusion deficits thereby helping to refine diagnostic assessment of CAD.

Cancer Metabolism and Tumor Heterogeneity: Imaging Perspectives Using MR Imaging and Spectroscopy

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Gigin Lin

2017-01-01

Full Text Available Cancer cells reprogram their metabolism to maintain viability via genetic mutations and epigenetic alterations, expressing overall dynamic heterogeneity. The complex relaxation mechanisms of nuclear spins provide unique and convertible tissue contrasts, making magnetic resonance imaging (MRI and magnetic resonance spectroscopy (MRS pertinent imaging tools in both clinics and research. In this review, we summarized MR methods that visualize tumor characteristics and its metabolic phenotypes on an anatomical, microvascular, microstructural, microenvironmental, and metabolomics scale. The review will progress from the utilities of basic spin-relaxation contrasts in cancer imaging to more advanced imaging methods that measure tumor-distinctive parameters such as perfusion, water diffusion, magnetic susceptibility, oxygenation, acidosis, redox state, and cell death. Analytical methods to assess tumor heterogeneity are also reviewed in brief. Although the clinical utility of tumor heterogeneity from imaging is debatable, the quantification of tumor heterogeneity using functional and metabolic MR images with development of robust analytical methods and improved MR methods may offer more critical roles of tumor heterogeneity data in clinics. MRI/MRS can also provide insightful information on pharmacometabolomics, biomarker discovery, disease diagnosis and prognosis, and treatment response. With these future directions in mind, we anticipate the widespread utilization of these MR-based techniques in studying in vivo cancer biology to better address significant clinical needs.

Insulin degradation products from perfused rat kidney

International Nuclear Information System (INIS)

Duckworth, W.C.; Hamel, F.G.; Liepnieks, J.; Peavy, D.; Frank, B.; Rabkin, R.

1989-01-01

The kidney is a major site for insulin metabolism, but the enzymes involved and the products generated have not been established. To examine the products, we have perfused rat kidneys with insulin specifically iodinated on either the A14 or the B26 tyrosine. Labeled material from both the perfusate and kidney extract was examined by Sephadex G50 and high-performance liquid chromatography (HPLC). In perfusate from a filtering kidney, 22% of the insulin-sized material was not intact insulin on HPLC. With the nonfiltering kidney, 10.6% was not intact insulin. Labeled material from HPLC was sulfitolyzed and reinjected on HPLC. By use of 125 I-iodo(A14)-insulin, almost all the degradation products contained an intact A-chain. By use of 125 I-iodo(B26)-insulin, several different B-chain-cleaved products were obtained. The material extracted from the perfused kidney was different from perfusate products but similar to intracellular products from hepatocytes, suggesting that cellular metabolism by kidney and liver are similar. The major intracellular product had characteristics consistent with a cleavage between the B16 and B17 amino acids. This product and several of the perfusate products are also produced by insulin protease suggesting that this enzyme is involved in the degradation of insulin by kidney

Pulmonary artery perfusion versus no perfusion during cardiopulmonary bypass for open heart surgery in adults

DEFF Research Database (Denmark)

Buggeskov, Katrine B; Grønlykke, Lars; Risom, Emilie C

2018-01-01

BACKGROUND: Available evidence has been inconclusive on whether pulmonary artery perfusion during cardiopulmonary bypass (CPB) is associated with decreased or increased mortality, pulmonary events, and serious adverse events (SAEs) after open heart surgery. To our knowledge, no previous systematic...... handsearched retrieved study reports and scanned citations of included studies and relevant reviews to ensure that no relevant trials were missed. We searched for ongoing trials and unpublished trials in the World Health Organization International Clinical Trials Registry Platform (ICTRP) and at clinicaltrials......). We used GRADE principles to assess the quality of evidence. MAIN RESULTS: We included in this review four RCTs (210 participants) reporting relevant outcomes. Investigators randomly assigned participants to pulmonary artery perfusion with blood versus no perfusion during CPB. Only one trial included...

TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

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Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

2015-06-15

Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r{sup 2} = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques.

TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

International Nuclear Information System (INIS)

Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S

2015-01-01

Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r 2 = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques

Value of chest X-ray combined with perfusion scan versus ventilation/perfusion scan in acute pulmonary embolism

NARCIS (Netherlands)

de Groot, M. R.; Turkstra, F.; van Marwijk Kooy, M.; Oostdijk, A. H.; van Beek, E. J.; Büller, H. R.

2000-01-01

The main purpose of ventilation scanning, as adjunct to perfusion lung scintigraphy, in acute pulmonary embolism is to allow for the classification of segmental perfusion defects as mismatched, which is generally accepted as proof for the presence of pulmonary embolism. We examined whether this

[The heterogeneity of blood flow on magnetic resonance imaging: a biomarker for grading cerebral astrocytomas].

Science.gov (United States)

Revert Ventura, A J; Sanz Requena, R; Martí-Bonmatí, L; Pallardó, Y; Jornet, J; Gaspar, C

2014-01-01

To study whether the histograms of quantitative parameters of perfusion in MRI obtained from tumor volume and peritumor volume make it possible to grade astrocytomas in vivo. We included 61 patients with histological diagnoses of grade II, III, or IV astrocytomas who underwent T2*-weighted perfusion MRI after intravenous contrast agent injection. We manually selected the tumor volume and peritumor volume and quantified the following perfusion parameters on a voxel-by-voxel basis: blood volume (BV), blood flow (BF), mean transit time (TTM), transfer constant (K(trans)), washout coefficient, interstitial volume, and vascular volume. For each volume, we obtained the corresponding histogram with its mean, standard deviation, and kurtosis (using the standard deviation and kurtosis as measures of heterogeneity) and we compared the differences in each parameter between different grades of tumor. We also calculated the mean and standard deviation of the highest 10% of values. Finally, we performed a multiparametric discriminant analysis to improve the classification. For tumor volume, we found statistically significant differences among the three grades of tumor for the means and standard deviations of BV, BF, and K(trans), both for the entire distribution and for the highest 10% of values. For the peritumor volume, we found no significant differences for any parameters. The discriminant analysis improved the classification slightly. The quantification of the volume parameters of the entire region of the tumor with BV, BF, and K(trans) is useful for grading astrocytomas. The heterogeneity represented by the standard deviation of BF is the most reliable diagnostic parameter for distinguishing between low grade and high grade lesions. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

Assessing the scale of tumor heterogeneity by complete hierarchical segmentation of MRI

International Nuclear Information System (INIS)

Gensheimer, Michael F; Ermoian, Ralph P; Hawkins, Douglas S; Trister, Andrew D

2015-01-01

In many cancers, intratumoral heterogeneity has been found in histology, genetic variation and vascular structure. We developed an algorithm to interrogate different scales of heterogeneity using clinical imaging. We hypothesize that heterogeneity of perfusion at coarse scale may correlate with treatment resistance and propensity for disease recurrence. The algorithm recursively segments the tumor image into increasingly smaller regions. Each dividing line is chosen so as to maximize signal intensity difference between the two regions. This process continues until the tumor has been divided into single voxels, resulting in segments at multiple scales. For each scale, heterogeneity is measured by comparing each segmented region to the adjacent region and calculating the difference in signal intensity histograms. Using digital phantom images, we showed that the algorithm is robust to image artifacts and various tumor shapes. We then measured the primary tumor scales of contrast enhancement heterogeneity in MRI of 18 rhabdomyosarcoma patients. Using Cox proportional hazards regression, we explored the influence of heterogeneity parameters on relapse-free survival. Coarser scale of maximum signal intensity heterogeneity was prognostic of shorter survival (p = 0.05). By contrast, two fractal parameters and three Haralick texture features were not prognostic. In summary, our algorithm produces a biologically motivated segmentation of tumor regions and reports the amount of heterogeneity at various distance scales. If validated on a larger dataset, this prognostic imaging biomarker could be useful to identify patients at higher risk for recurrence and candidates for alternative treatment. (paper)

Arrhythmogenic drugs can amplify spatial heterogeneities in the electrical restitution in perfused guinea-pig heart: An evidence from assessments of monophasic action potential durations and JT intervals.

Directory of Open Access Journals (Sweden)

Oleg E Osadchii

Full Text Available Non-uniform shortening of the action potential duration (APD90 in different myocardial regions upon heart rate acceleration can set abnormal repolarization gradients and promote arrhythmia. This study examined whether spatial heterogeneities in APD90 restitution can be amplified by drugs with clinically proved proarrhythmic potential (dofetilide, quinidine, procainamide, and flecainide and, if so, whether these effects can translate to the appropriate changes of the ECG metrics of ventricular repolarization, such as JT intervals. In isolated, perfused guinea-pig heart preparations, monophasic action potentials and volume-conducted ECG were recorded at progressively increased pacing rates. The APD90 measured at distinct ventricular sites, as well as the JTpeak and JTend values were plotted as a function of preceding diastolic interval, and the maximum slopes of the restitution curves were determined at baseline and upon drug administration. Dofetilide, quinidine, and procainamide reverse rate-dependently prolonged APD90 and steepened the restitution curve, with effects being greater at the endocardium than epicardium, and in the right ventricular (RV vs. the left ventricular (LV chamber. The restitution slope was increased to a greater extent for the JTend vs. the JTpeak interval. In contrast, flecainide reduced the APD90 restitution slope at LV epicardium without producing effect at LV endocardium and RV epicardium, and reduced the JTpeak restitution slope without changing the JTend restitution. Nevertheless, with all agents, these effects translated to the amplified epicardial-to-endocardial and the LV-to-RV non-uniformities in APD90 restitution, paralleled by the increased JTend vs. JTpeak difference in the restitution slope. In summary, these findings suggest that arrhythmic drug profiles are partly attributable to the accentuated regional heterogeneities in APD90 restitution, which can be indirectly determined through ECG assessments of the

Arrhythmogenic drugs can amplify spatial heterogeneities in the electrical restitution in perfused guinea-pig heart: An evidence from assessments of monophasic action potential durations and JT intervals.

Science.gov (United States)

Osadchii, Oleg E

2018-01-01

Non-uniform shortening of the action potential duration (APD90) in different myocardial regions upon heart rate acceleration can set abnormal repolarization gradients and promote arrhythmia. This study examined whether spatial heterogeneities in APD90 restitution can be amplified by drugs with clinically proved proarrhythmic potential (dofetilide, quinidine, procainamide, and flecainide) and, if so, whether these effects can translate to the appropriate changes of the ECG metrics of ventricular repolarization, such as JT intervals. In isolated, perfused guinea-pig heart preparations, monophasic action potentials and volume-conducted ECG were recorded at progressively increased pacing rates. The APD90 measured at distinct ventricular sites, as well as the JTpeak and JTend values were plotted as a function of preceding diastolic interval, and the maximum slopes of the restitution curves were determined at baseline and upon drug administration. Dofetilide, quinidine, and procainamide reverse rate-dependently prolonged APD90 and steepened the restitution curve, with effects being greater at the endocardium than epicardium, and in the right ventricular (RV) vs. the left ventricular (LV) chamber. The restitution slope was increased to a greater extent for the JTend vs. the JTpeak interval. In contrast, flecainide reduced the APD90 restitution slope at LV epicardium without producing effect at LV endocardium and RV epicardium, and reduced the JTpeak restitution slope without changing the JTend restitution. Nevertheless, with all agents, these effects translated to the amplified epicardial-to-endocardial and the LV-to-RV non-uniformities in APD90 restitution, paralleled by the increased JTend vs. JTpeak difference in the restitution slope. In summary, these findings suggest that arrhythmic drug profiles are partly attributable to the accentuated regional heterogeneities in APD90 restitution, which can be indirectly determined through ECG assessments of the JTend vs. JTpeak

Myocardial perfusion scintigraphy - possibilities of diagnosing CAD

International Nuclear Information System (INIS)

Tsonevska, A.

1998-01-01

A reviewing the diagnostic methods used in the intricate process of evaluating CAD patients in a attempt to establish the role played by radionuclide methods in the diagnostic strategy is done. The perfusion cardiotropic radiopharmaceuticals used and the various methods of evaluating myocardial are discussed. Although 210 Tl-chloride is the most widely used myocardial perfusion agent, recently 99m Tc-MIBI is proposed as an alternative because of its advantages. Myocardial perfusion assessment is done by various techniques depending on the specific aim, each of them having its proper advantages and shortcomings. The inference is reached that regardless of the routine practical implementation of myocardial perfusion scintigraphy and comprehensive studies along this line in course, there are problems still not well enough clarified awaiting solution

Goal-directed-perfusion in neonatal aortic arch surgery.

Science.gov (United States)

Cesnjevar, Robert Anton; Purbojo, Ariawan; Muench, Frank; Juengert, Joerg; Rueffer, André

2016-07-01

Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

Impairment of myocardial perfusion in children with sickle cell disease; Alteration de la perfusion myocardique chez l'enfant drepanocytaire

Energy Technology Data Exchange (ETDEWEB)

Maunoury, C. [Hopital Necker-Enfants-Malades, Service de Medecine Nucleaire, 75 - Paris (France); Acar, P. [Centre Hospitalier Universitaire, Hopital des Enfants, Service de Cardiologie Pediatrique, 31 - Toulouse (France); Montalembert, M. de [Hopital Necker-Enfants-Malades, Service de Pediatrie Generale, 75 - Paris (France)

2003-10-01

While brain, bone and spleen strokes are well documented in children with sickle cell disease (SCD), impairment of myocardial perfusion is an unknown complication. Non invasive techniques such as exercise testing and echocardiography have a low sensitivity to detect myocardial ischemia in patients with SCD. We have prospectively assessed myocardial perfusion with Tl-201 SPECT in 23 patients with SCD (10 female, 13 male, mean age 12 {+-} 5 years). Myocardial SPECT was performed after stress and 3 hours later after reinjection on a single head gamma camera equipped with a LEAP collimator (64 x 64 matrix size format, 30 projections over 180 deg C, 30 seconds per step). Left ventricular ejection fraction (LVEF) was assessed by equilibrium radionuclide angiography at rest on the same day. Myocardial perfusion was impaired in 14/23 patients: 9 reversible defects and 5 fixed defects. The left ventricular cavity was dilated in 14/23 patients. The mean LVEF was 63 {+-} 9%. There was no relationship between myocardial perfusion and left ventricular dilation or function. The frequent impairment of myocardial perfusion in children with SCD could lead to suggest a treatment with hydroxyurea, an improvement of perfusion can be noted with hydroxyurea. (author)

Comparative study of adenosine and exercise 201Tl myocardial perfusion tomographic imaging for detection of coronary heart disease

International Nuclear Information System (INIS)

Wang Xiong

1997-01-01

To compare diagnostic accuracy of adenosine and exercise 201 Tl myocardial perfusion tomographic imaging for detection of coronary heart disease (CHD) in patients with a normal rest ECG and no history of myocardial infarction, 81 patients with CHD and 10 normal control subjects underwent adenosine myocardial perfusion imaging, exercise nuclide myocardial perfusion imaging was performed in 117 patients with CHD and 16 normal control subjects, two groups also had coronary arteriography. Both exercise and adenosine testing parameters were analysed. It is shown: 1) The sensitivity and specificity for detection of CHD were 79% vs 80% for adenosine group and 81% vs 81% for exercise myocardial perfusion imaging group respectively. There was no significant difference in comparison with two matched groups (χ 2 = 1.13, χ 2 = 0.18, χ 2 = 0.12, P>0.05). 2) Side effects induced by adenosine accounted for 89% of patients, all symptoms were mild and disappeared quickly after the termination of the study except in 2 cases withdrawal of infusion needed because of severe angina pectoris. Adenosine myocardial perfusion imaging is a safe and sensitive method for detection of CHD. The diagnostic value of adenosine test is similar to that of exercise myocardial perfusion imaging and particularly useful in evaluating patients unable to perform exercise test or achieve adequate level of exercise

Effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies

International Nuclear Information System (INIS)

Murase, Kenya; Nanjo, Takafumi; Ii, Satoshi; Miyazaki, Shohei; Hirata, Masaaki; Sugawara, Yoshifumi; Kudo, Masayuki; Sasaki, Kousuke; Mochizuki, Teruhito

2005-01-01

The purpose of this study was to investigate the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using multi-detector row CT (MDCT). Following the standard CT perfusion study protocol, continuous (cine) scans (1 s/rotation x 60 s) consisting of four 5 mm thick contiguous slices were performed using an MDCT scanner with a tube voltage of 80 kVp and a tube current of 200 mA. We generated the simulated images with tube currents of 50 mA, 100 mA and 150 mA by adding the corresponding noise to the raw scan data of the original image acquired above using a noise simulation tool. From the original and simulated images, we generated the functional images of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in seven patients with cerebrovascular disease, and compared the correlation coefficients (CCs) between the perfusion parameter values obtained from the original and simulated images. The coefficients of variation (CVs) in the white matter were also compared. The CC values deteriorated with decreasing tube current. There was a significant difference between 50 mA and 100 mA for all perfusion parameters. The CV values increased with decreasing tube current. There were significant differences between 50 mA and 100 mA and between 100 mA and 150 mA for CBF. For CBV and MTT, there was also a significant difference between 150 mA and 200 mA. This study will be useful for understanding the effect of x-ray tube current on the accuracy of cerebral perfusion parameters obtained by CT perfusion studies using MDCT, and for selecting the tube current

Gray matter perfusion correlates with disease severity in ALS.

Science.gov (United States)

Rule, Randall R; Schuff, Norbert; Miller, Robert G; Weiner, Michael W

2010-03-09

The goal of this study is to determine if regional brain perfusion, as measured by arterial spin labeling (ASL) MRI, is correlated with clinical measures of amyotrophic lateral sclerosis (ALS) disease severity. The presence of such a relationship would indicate a possible role for ASL perfusion as a marker of disease severity and upper motor neuron involvement in ALS. Disease severity was assessed in 16 subjects with ALS (age 54 +/- 11) using the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and the pulmonary function measure, forced vital capacity (FVC). Upper motor neuron involvement was assessed by testing rapid tapping of the fingers and feet. Magnetic resonance perfusion images were coregistered with structural T1-weighted MRI, corrected for partial volume effects using the structural images and normalized to a study-specific atlas. Correlations between perfusion and ALS disease severity were analyzed, using statistical parametric mapping, and including age as a factor. Analyses were adjusted for multiple clusters. ALS severity, as measured by the ALSFRS and FVC, was correlated with gray matter perfusion. This correlation was predominantly observed in the hemisphere contralateral to the more affected limbs. ALSFRS scores correlated with perfusion in the contralateral frontal and parietal lobe (p frontal lobe (p frontal lobe (p Upper motor neuron involvement, as measured by rapid finger tapping, correlated bilaterally with perfusion in the middle cingulate gyrus (p < 0.001). Amyotrophic lateral sclerosis (ALS) severity is correlated with brain perfusion as measured by arterial spin labeling (ASL) perfusion. This correlation appears to be independent of brain atrophy. ASL perfusion may be a useful tool for monitoring disease progression and assessing treatment effects in ALS.

CT perfusion study of neck lymph nodes

International Nuclear Information System (INIS)

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

2011-01-01

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

Brain perfusion CT in acute stroke: current status

Energy Technology Data Exchange (ETDEWEB)

Koenig, Matthias E-mail: matthias.koenig@ruhr-uni-bochum.de

2003-03-01

Dynamic perfusion CT has become a widely accepted imaging modality for the diagnostic workup of acute stroke patients. Although compared with standard spiral CT the use of multislice CT has broadened the range from which perfusion data may be derived in a single scan run. The advent of multidetector row technology has not really overcome the limited 3D capability of this technique. Multidetector CT angiography (CTA) of the cerebral arteries may in part compensate for this by providing additional information about the cerebrovascular status. This article describes the basics of cerebral contrast bolus scanning with a special focus on optimization of contrast/noise in order to ensure high quality perfusion maps. Dedicated scan protocols including low tube voltage (80 kV) as well as the use of highly concentrated contrast media are amongst the requirements to achieve optimum contrast signal from the short bolus passage through the brain. Advanced pre and postprocessing algorithms may help reduce the noise level, which may become critical in unconscious stroke victims. Two theoretical concepts have been described for the calculation of tissue perfusion from contrast bolus studies, both of which can be equally employed for brain perfusion imaging. For each perfusion model there are some profound limitations regarding the validity of perfusion values derived from ischemic brain areas. This makes the use of absolute quantitative cerebral blood flow (CBF) values for the discrimination of the infarct core from periinfarct ischemia questionable. Multiparameter imaging using maps of CBF, cerebral blood volume (CBV), and a time parameter of the local bolus transit enables analyzing of the cerebral perfusion status in detail. Perfusion CT exceeds plain CT in depicting cerebral hypoperfusion at its earliest stage yielding a sensitivity of about 90% for the detection of embolic and hemodynamic lesions within cerebral hemispheres. Qualitative assessment of brain perfusion can be

Perfusion MRI in CNS disease: current concepts

International Nuclear Information System (INIS)

Essig, M.; Giesel, F.; Le-Huu, M.; Stieltjes, B.; Tengg, H. von; Weber, M.-A.

2004-01-01

Today there are several indications for cerebral perfusion MRI. The major indications routinely used in increasing numbers of imaging centers include cerebrovascular disease, tumor imaging and recently psychiatric disorders. Perfusion MRI is based on the injection of a gadolinium chelate and the rapid acquisition of images as the bolus of contrast agent passes through the blood vessels in the brain. The contrast agent causes a signal change; this signal change over time can be analysed to measure cerebral hemodynamics. The quality of brain perfusion studies is very dependent on the contrast agent used: a robust and strong signal decrease with a compact bolus is needed. MultiHance (gadobenate dimeglumine, Gd-BOPTA) is the first of a new class of paramagnetic MR contrast agents with a weak affinity for serum proteins. Due to the interaction of Gd-BOPTA with serum albumin, MultiHance presents with significantly higher T1- and T2-relaxivities enabling a sharper bolus profile. This article reviews the indications of perfusion MRI and the performance of MultiHance in MR perfusion of different diseases. Previous studies using perfusion MRI for a variety of purposes required the use of double dose of contrast agent to achieve a sufficiently large signal drop to enable the acquisition of a clear input function and the calculation of perfusion rCBV and rCBF maps of adequate quality. Recent studies with Multi-Hance suggest that only a single dose of this agent is needed to cause a signal drop of about 30% which is sufficient to allow the calculation of high quality rCBV and rCBF maps. (orig.)

A model system for perfusion quantification using FAIR

DEFF Research Database (Denmark)

Andersen, Irene Klærke; Sidaros, Karam; Gesmar, Henrik

2000-01-01

Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom....

A model system for perfusion quantification using FAIR

DEFF Research Database (Denmark)

Andersen, I.K.; Sidaros, Karam; Gesmar, H

2000-01-01

Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom...

SPECT Analysis of Cardiac Perfusion Changes After Whole-Breast/Chest Wall Radiation Therapy With or Without Active Breathing Coordinator: Results of a Randomized Phase 3 Trial

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Zellars, Richard, E-mail: zellari@jhmi.edu [Johns Hopkins Medical Institution, Baltimore, Maryland (United States); Bravo, Paco E. [University of Washington Medical Center, Seattle, Washington (United States); Tryggestad, Erik [Mayo Clinic, Rochester, Minnesota (United States); Hopfer, Kari [Hahnemann University, Philadelphia, Pennsylvania (United States); Myers, Lee; Tahari, Abdel; Asrari, Fariba; Ziessman, Harvey [Johns Hopkins Medical Institution, Baltimore, Maryland (United States); Garrett-Mayer, Elizabeth [Medical University of South Carolina, Charleston, South Carolina (United States)

2014-03-15

Purpose: Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC. Methods and Materials: Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before and 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression. Results: Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits. Conclusions: In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits.

SPECT Analysis of Cardiac Perfusion Changes After Whole-Breast/Chest Wall Radiation Therapy With or Without Active Breathing Coordinator: Results of a Randomized Phase 3 Trial

International Nuclear Information System (INIS)

Zellars, Richard; Bravo, Paco E.; Tryggestad, Erik; Hopfer, Kari; Myers, Lee; Tahari, Abdel; Asrari, Fariba; Ziessman, Harvey; Garrett-Mayer, Elizabeth

2014-01-01

Purpose: Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC. Methods and Materials: Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before and 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression. Results: Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits. Conclusions: In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits

Influence of ocular perfusion pressure fluctuation on glaucoma

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Min-Zi Ren

2015-12-01

Full Text Available AIM:To investigate the influence of ocular perfusion pressure fluctuation on glaucoma. METHODS:Forty patients with primary open angle glaucoma from January 2013 to June 2015 in our hospital were used as observation group and 40 families were used as control group. Circadian fluctuation of intraocular pressure, blood pressure and ocular perfusion pressure in 24h were determined to obtain systolic ocular perfusion pressure(SOPP, diastolic ocular perfusion pressure(DOPPand mean ocular perfusion pressure(MOPP. Pearson linear correlation was used to analyze the correlation of circadian MOPP fluctuation with cup-disc ratio, mean defect(MDand the picture standard deviation(PSD. RESULTS:The fluctuation of MOPP, SOPP and DOPP of observation group were significantly higher than those of control group(Pr=-0.389, 95%CI:-0.612～-0.082; P=0.011, was positively correlated with PSD(r=0.512, 95%CI:0.139 ～0.782; P=0.008; no correlation was found between it and the vertical cup-disc ratio(r=0.115, 95%CI:0.056～0.369; P=0.355. CONCLUSION:Ocular perfusion pressure fluctuations in patients with primary open angle glaucoma may reflect the severity of the disease and may make the situation aggravating. Therefore through perfusion pressure monitor in 24h may help us understand the ocular blood flow and the development of primary open-angle glaucoma.

Meta-Analysis of Stress Myocardial Perfusion Imaging

Science.gov (United States)

2017-06-06

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

Dynamic CT myocardial perfusion imaging

International Nuclear Information System (INIS)

Caruso, Damiano; Eid, Marwen; Schoepf, U. Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie

2016-01-01

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

Dynamic CT myocardial perfusion imaging

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

2016-10-15

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

Lung perfusion scintigraphy by SPECT

International Nuclear Information System (INIS)

Hirayama, Takanobu

1990-01-01

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

Reversible ventilation and perfusion abnormalities in unilateral obstructed lung

International Nuclear Information System (INIS)

Ward, H.E.; Jones, R.L.; King, E.G.; Sproule, B.J.; Fortune, R.L.

1982-01-01

An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (/sup 133/Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected /sup 133/Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal

Monitoring Cell Death in Regorafenib-Treated Experimental Colon Carcinomas Using Annexin-Based Optical Fluorescence Imaging Validated by Perfusion MRI.

Directory of Open Access Journals (Sweden)

Philipp M Kazmierczak

Full Text Available To investigate annexin-based optical fluorescence imaging (OI for monitoring regorafenib-induced early cell death in experimental colon carcinomas in rats, validated by perfusion MRI and multiparametric immunohistochemistry.Subcutaneous human colon carcinomas (HT-29 in athymic rats (n = 16 were imaged before and after a one-week therapy with regorafenib (n = 8 or placebo (n = 8 using annexin-based OI and perfusion MRI at 3 Tesla. Optical signal-to-noise ratio (SNR and MRI tumor perfusion parameters (plasma flow PF, mL/100mL/min; plasma volume PV, % were assessed. On day 7, tumors underwent immunohistochemical analysis for tumor cell apoptosis (TUNEL, proliferation (Ki-67, and microvascular density (CD31.Apoptosis-targeted OI demonstrated a tumor-specific probe accumulation with a significant increase of tumor SNR under therapy (mean Δ +7.78±2.95, control: -0.80±2.48, p = 0.021. MRI detected a significant reduction of tumor perfusion in the therapy group (mean ΔPF -8.17±2.32 mL/100 mL/min, control -0.11±3.36 mL/100 mL/min, p = 0.036. Immunohistochemistry showed significantly more apoptosis (TUNEL; 11392±1486 vs. 2921±334, p = 0.001, significantly less proliferation (Ki-67; 1754±184 vs. 2883±323, p = 0.012, and significantly lower microvascular density (CD31; 107±10 vs. 182±22, p = 0.006 in the therapy group.Annexin-based OI allowed for the non-invasive monitoring of regorafenib-induced early cell death in experimental colon carcinomas, validated by perfusion MRI and multiparametric immunohistochemistry.

Characteristics of Brain Perfusion in Patients of Parkinson's Disease

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Jeong, Young Jin; Park, Min Jung; Kim, Jae Woo; Kang, Young Kang [Dong-A University College of Medicine, Busan (Korea, Republic of)

2008-02-15

It was well known that cerebral blood perfusion is normal or diffusely decreased in the majority of patients with Parkinson's disease (PD). Actually we interpreted brain perfusion SPECT images of PD patients in the clinical situation, we observed various cerebral perfusion patterns in patients with PD. So we performed brain perfusion SPECT to know the brain perfusion patterns of PD patients and the difference of perfusion patterns according to the sex and the age. Also we classified PD patients into small groups based on the brain perfusion pattern. Two hundred nineteen patients (M: 70, F: 149, mean age: 62.9{+-}6.9 y/o) who were diagnosed as PD without dementia clinically and 55 patients (M: 15, F: 40, mean age: 61.4{+-}9.2 y/o) as normal controls who had no past illness history were performed {sup 99m}Tc-HMPAO brain perfusion SPECT and neuropsychological test. At first, we compared all patients with PD and normal controls. Brain perfusion in left inferior frontal gyrus, left insula, left transverse temporal gyrus, left inferior parietal lobule, left superior parietal lobule, right precuneus, right caudate tail were lower in patients with PD than normal controls. Secondly, we compared male and female patients with PD and normal controls, respectively. Brain perfusion SPECT showed more decreased cerebral perfusion in left hemisphere than right side in both male and female patients compared to normal controls. And there was larger hypoperfusion area in female patients compared with male. Thirdly, we classified patients with PD and normal controls into 4 groups according to the age and compared brain perfusion respectively. In patient below fifties, brain perfusion in both occipitoparietal and left temporal lobe were lower in PD group. As the patients with PD grew older, hypoperfusion area were shown in both frontal, temporal and limbic lobes. Fourthly, We were able to divide patients into small groups based on cerebral perfusion pattern. There was normal

CT Perfusion Characteristics Identify Metastatic Sites in Liver

Directory of Open Access Journals (Sweden)

Yuan Wang

2015-01-01

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

Selective Heart, Brain and Body Perfusion in Open Aortic Arch Replacement.

Science.gov (United States)

Maier, Sven; Kari, Fabian; Rylski, Bartosz; Siepe, Matthias; Benk, Christoph; Beyersdorf, Friedhelm

2016-09-01

Open aortic arch replacement is a complex and challenging procedure, especially in post dissection aneurysms and in redo procedures after previous surgery of the ascending aorta or aortic root. We report our experience with the simultaneous selective perfusion of heart, brain, and remaining body to ensure optimal perfusion and to minimize perfusion-related risks during these procedures. We used a specially configured heart-lung machine with a centrifugal pump as arterial pump and an additional roller pump for the selective cerebral perfusion. Initial arterial cannulation is achieved via femoral artery or right axillary artery. After lower body circulatory arrest and selective antegrade cerebral perfusion for the distal arch anastomosis, we started selective lower body perfusion simultaneously to the selective antegrade cerebral perfusion and heart perfusion. Eighteen patients were successfully treated with this perfusion strategy from October 2012 to November 2015. No complications related to the heart-lung machine and the cannulation occurred during the procedures. Mean cardiopulmonary bypass time was 239 ± 33 minutes, the simultaneous selective perfusion of brain, heart, and remaining body lasted 55 ± 23 minutes. One patient suffered temporary neurological deficit that resolved completely during intensive care unit stay. No patient experienced a permanent neurological deficit or end-organ dysfunction. These high-risk procedures require a concept with a special setup of the heart-lung machine. Our perfusion strategy for aortic arch replacement ensures a selective perfusion of heart, brain, and lower body during this complex procedure and we observed excellent outcomes in this small series. This perfusion strategy is also applicable for redo procedures.

Accuracy and feasibility of dynamic contrast-enhanced 3D MR imaging in the assessment of lung perfusion: comparison with Tc-99 MAA perfusion scintigraphy

International Nuclear Information System (INIS)

Yilmaz, E.; Akkoclu, A.; Degirmenci, B.; Cooper, R.A.; Sengun, B.; Gulcu, A.; Osma, E.; Ucan, E.S.

2005-01-01

AIM: The aim of this study was to correlate findings of perfusion magnetic resonance imaging (MRI) and perfusion scintigraphy in cases where there was a suspicion of abnormal pulmonary vasculature, and to evaluate the usefulness of MRI in the detection of perfusion deficits of the lung. METHODS: In all, 17 patients with suspected abnormality of the pulmonary vasculature underwent dynamic contrast-enhanced MRI. T1-weighted 3D fast-field echo pulse sequences were obtained (TR/TE 3.3/1.58 ms; flip angle 30 deg ; slice thickness 12 to 15 mm). The dynamic study was acquired in the coronal plane following administration of 0.1 mmol/kg gadopentetate dimeglumine. A total of 8 to 10 sections repeated 20 to 25 times at intervals of 1 s were performed. Perfusion lung scintigraphy was carried out a maximum of 48 h before the MR examination in all cases. Two radiologists, who were blinded to the clinical data and results of other imaging methods, reviewed all coronal sections. MR perfusion images were independently assessed in terms of segmental or lobar perfusion defects in the 85 lobes of the 17 individuals, and the findings were compared with the results of scintigraphy. RESULTS: Of the 17 patients, 8 were found to have pulmonary emboli, 2 chronic obstructive pulmonary disease with emphysema, 2 bullous emphysema, 2 Takayasu arteritis and 1 had a hypoplastic pulmonary artery. Pulmonary perfusion was completely normal in 2 cases. In 35 lobes, perfusion defects were detected using both methods, in 4 with MR alone and in 9 only with scintigraphy. There was good agreement between MRI and scintigraphy findings (kappa=0.695). CONCLUSION: Pulmonary perfusion MRI is a new alternative to scintigraphy in the evaluation of pulmonary perfusion for various lung disorders. In addition, this technique allows measurement and quantification of pulmonary perfusion abnormalities

Optimization of perfusion studies using Atropine

International Nuclear Information System (INIS)

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

2002-01-01

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

Heterogeneity of equilibrium molten globule state of cytochrome c induced by weak salt denaturants under physiological condition.

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Hamidur Rahaman

Full Text Available While many proteins are recognized to undergo folding via intermediate(s, the heterogeneity of equilibrium folding intermediate(s along the folding pathway is less understood. In our present study, FTIR spectroscopy, far- and near-UV circular dichroism (CD, ANS and tryptophan fluorescence, near IR absorbance spectroscopy and dynamic light scattering (DLS were used to study the structural and thermodynamic characteristics of the native (N, denatured (D and intermediate state (X of goat cytochorme c (cyt-c induced by weak salt denaturants (LiBr, LiCl and LiClO4 at pH 6.0 and 25°C. The LiBr-induced denaturation of cyt-c measured by Soret absorption (Δε400 and CD ([θ]409, is a three-step process, N ↔ X ↔ D. It is observed that the X state obtained along the denaturation pathway of cyt-c possesses common structural and thermodynamic characteristics of the molten globule (MG state. The MG state of cyt-c induced by LiBr is compared for its structural and thermodynamic parameters with those found in other solvent conditions such as LiCl, LiClO4 and acidic pH. Our observations suggest: (1 that the LiBr-induced MG state of cyt-c retains the native Met80-Fe(III axial bond and Trp59-propionate interactions; (2 that LiBr-induced MG state of cyt-c is more compact retaining the hydrophobic interactions in comparison to the MG states induced by LiCl, LiClO4 and 0.5 M NaCl at pH 2.0; and (3 that there exists heterogeneity of equilibrium intermediates along the unfolding pathway of cyt-c as highly ordered (X1, classical (X2 and disordered (X3, i.e., D ↔ X3 ↔ X2 ↔ X1 ↔ N.

Selective cerebral perfusion prevents abnormalities in glutamate cycling and neuronal apoptosis in a model of infant deep hypothermic circulatory arrest and reperfusion.

Science.gov (United States)

Kajimoto, Masaki; Ledee, Dolena R; Olson, Aaron K; Isern, Nancy G; Robillard-Frayne, Isabelle; Des Rosiers, Christine; Portman, Michael A

2016-11-01

Deep hypothermic circulatory arrest is often required for the repair of complex congenital cardiac defects in infants. However, deep hypothermic circulatory arrest induces neuroapoptosis associated with later development of neurocognitive abnormalities. Selective cerebral perfusion theoretically provides superior neural protection possibly through modifications in cerebral substrate oxidation and closely integrated glutamate cycling. We tested the hypothesis that selective cerebral perfusion modulates glucose utilization, and ameliorates abnormalities in glutamate flux, which occur in association with neuroapoptosis during deep hypothermic circulatory arrest. Eighteen infant male Yorkshire piglets were assigned randomly to two groups of seven (deep hypothermic circulatory arrest or deep hypothermic circulatory arrest with selective cerebral perfusion for 60 minutes at 18℃) and four control pigs without cardiopulmonary bypass support. Carbon-13-labeled glucose as a metabolic tracer was infused, and gas chromatography-mass spectrometry and nuclear magnetic resonance were used for metabolic analysis in the frontal cortex. Following 2.5 h of cerebral reperfusion, we observed similar cerebral adenosine triphosphate levels, absolute levels of lactate and citric acid cycle intermediates, and carbon-13 enrichment among three groups. However, deep hypothermic circulatory arrest induced significant abnormalities in glutamate cycling resulting in reduced glutamate/glutamine and elevated γ-aminobutyric acid/glutamate along with neuroapoptosis, which were all prevented by selective cerebral perfusion. The data suggest that selective cerebral perfusion prevents these modifications in glutamate/glutamine/γ-aminobutyric acid cycling and protects the cerebral cortex from apoptosis. © The Author(s) 2016.

Nuclear cardiology: Myocardial perfusion and function

International Nuclear Information System (INIS)

Seldin, D.W.

1991-01-01

Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references

MRI of pulmonary perfusion; MRT der Lungenperfusion

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

2006-04-15

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

Cyclooxygenase-2-dependent bronchoconstriction in perfused rat lungs exposed to endotoxin.

OpenAIRE

Uhlig, S.; Nüsing, R.; von Bethmann, A.; Featherstone, R. L.; Klein, T.; Brasch, F.; Müller, K. M.; Ullrich, V.; Wendel, A.

1996-01-01

BACKGROUND: Lipopolysaccharides (LPS), widely used to study the mechanisms of gram-negative sepsis, increase airway resistance by constriction of terminal bronchioles. The role of the cyclooxygenase (COX) isoenzymes and their prostanoid metabolites in this process was studied. MATERIALS AND METHODS: Pulmonary resistance, the release of thromboxane (TX) and the expression of COX-2 mRNA were measured in isolated blood-free perfused rat lungs exposed to LPS. RESULTS: LPS induced the release of T...

Dynamic contrast enhanced MRI for perfusion quantification

DEFF Research Database (Denmark)

Andersen, Irene Klærke

2002-01-01

Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... clinical value both in diagnosis and treatment of such pathologies. One approach for perfusion quanti cation involves using the contrast mechanism that a ects the transverse relaxation rates of the magnetization, R2 or R 2 , since this provides the most pronounced effect. However, the linearity between...

Perfusion imaging with single-photon emission computed tomography

International Nuclear Information System (INIS)

Holman, B.L.; Hill, T.C.

1987-01-01

SPECT with perfusion tracers is useful in a number of circumstances: (1) In acute cerebral infarction while the CT scan may be normal for several days after onset of symptoms, the uptake of SPECT perfusion tracers will be altered immediately after the onset of the stroke. Even when the CT scan has become abnormal, the physiologic abnormality may exceed the anatomic abnormality. One may, therefore be able to measure the extent of the reversibly ischemic tissue early enough to justify more agressive therapeutic interventions. (2) For endarterectomy and other surgical and medical therapies serial measurements of regional cerebral perfusion with SPECT may provide a readily available tool to assess their efficacy. (3) SPECT perfusion imaging may become the method of choice for the diagnosis and evaluation of Alzheimer's disease. (4) In patients with epilepsy, the extent and location of the abnormally perfused focus may be important to medical and surgical management. Follow-up examination may be useful in documenting the effectiveness of therapy

Pathologic evaluation of normal and perfused term placental tissue

DEFF Research Database (Denmark)

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

2014-01-01

This study reports for the 1st time the incidence and interobserver variation of morphologic findings in a series of 34 term placentas from pregnancies with normal outcome used for perfusion studies. Histologic evaluation of placental tissue is challenging, especially when it comes to defining...... "normal tissue" versus "pathologic lesions." A scoring system for registration of abnormal morphologic findings was developed. Light microscopic examination was performed independently by 2 pathologists, and interobserver variation was analyzed. Findings in normal and perfused tissue were compared...... and selected findings were tested against success parameters from the perfusions. Finally, the criteria for frequent lesions with fair to poor interobserver variation in the nonperfused tissue were revised and reanalyzed. In the perfused tissue, the perfusion artefact "trophoblastic vacuolization," which...

Development of an Extracorporeal Perfusion Device for Small Animal Free Flaps.

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Andreas M Fichter

Full Text Available Extracorporeal perfusion (ECP might prolong the vital storage capabilities of composite free flaps, potentially opening a wide range of clinical applications. Aim of the study was the development a validated low-cost extracorporeal perfusion model for further research in small animal free flaps.After establishing optimal perfusion settings, a specially designed extracorporeal perfusion system was evaluated during 8-hour perfusion of rat epigastric flaps followed by microvascular free flap transfer. Controls comprised sham-operation, ischemia and in vivo perfusion. Flaps and perfusate (diluted blood were closely monitored by blood gas analysis, combined laser Doppler flowmetry and remission spectroscopy and Indocyanine-Green angiography. Evaluations were complemented by assessment of necrotic area and light microscopy at day 7.ECP was established and maintained for 8 hours with constant potassium and pH levels. Subsequent flap transfer was successful. Notably, the rate of necrosis of extracorporeally perfused flaps (27% was even lower than after in vivo perfusion (49%, although not statistically significant (P = 0,083. After sham-operation, only 6% of the total flap area became necrotic, while 8-hour ischemia led to total flap loss (98%. Angiographic and histological findings confirmed these observations.Vital storage capabilities of microvascular flaps can be prolonged by temporary ECP. Our study provides important insights on the pathophysiological processes during extracorporeal tissue perfusion and provides a validated small animal perfusion model for further studies.

Computed Tomography Perfusion Imaging for the Diagnosis of Hepatic Alveolar Echinococcosis

Science.gov (United States)

Sade, Recep; Kantarci, Mecit; Genc, Berhan; Ogul, Hayri; Gundogdu, Betul; Yilmaz, Omer

2018-01-01

Objective: Alveolar echinococcosis (AE) is a rare life-threatening parasitic infection. Computed tomography perfusion (CTP) imaging has the potential to provide both quantitative and qualitative information about the tissue perfusion characteristics. The purpose of this study was the examination of the characteristic features and feasibility of CTP in AE liver lesions. Material and Methods: CTP scanning was performed in 25 patients who had a total of 35 lesions identified as AE of the liver. Blood flow (BF), blood volume (BV), portal venous perfusion (PVP), arterial liver perfusion (ALP), and hepatic perfusion indexes (HPI) were computed for background liver parenchyma and each AE lesion. Results: Significant differences were detected between perfusion values of the AE lesions and background liver tissue. The BV, BF, ALP, and PVP values for all components of the AE liver lesions were significantly lower than the normal liver parenchyma (p<0.01). Conclusions: We suggest that perfusion imaging can be used in AE of the liver. Thus, the quantitative knowledge of perfusion parameters are obtained via CT perfusion imaging. PMID:29531482

Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

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Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

2015-07-15

To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

Effect of Defocused CO2 Laser on Equine Tissue Perfusion

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Bergh A

2006-03-01

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

Spatio-temporal analysis of blood perfusion by imaging photoplethysmography

Science.gov (United States)

Zaunseder, Sebastian; Trumpp, Alexander; Ernst, Hannes; Förster, Michael; Malberg, Hagen

2018-02-01

Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements. This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio). Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are influenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points. This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance.

Nifedipine and thallium-201 myocardial perfusion in progressive systemic sclerosis

International Nuclear Information System (INIS)

Kahan, A.; Devaux, J.Y.; Amor, B.

1986-01-01

Heart disease in patients with progressive systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance of the coronary microcirculation. To determine whether abnormalities of myocardial perfusion in this disorder are potentially reversible, we evaluated the effect of the coronary vasodilator nifedipine on myocardial perfusion assessed by thallium-201 scanning in 20 patients. Thallium-201 single-photon-emission computerized tomography was performed under control conditions and 90 minutes after 20 mg of oral nifedipine. The mean (+/- SD) number of left ventricular segments with perfusion defects decreased from 5.3 +/- 2.0 to 3.3 +/- 2.2 after nifedipine (P = 0.0003). Perfusion abnormalities were quantified by a perfusion score (0 to 2.0) assigned to each left ventricular segment and by a global perfusion score (0 to 18) for the entire left ventricle. The mean perfusion score in segments with resting defects increased from 0.97 +/- 0.24 to 1.26 +/- 0.44 after nifedipine (P less than 0.00001). The mean global perfusion score increased from 11.2 +/- 1.7 to 12.8 +/- 2.4 after nifedipine (P = 0.003). The global perfusion score increased by at least 2.0 in 10 patients and decreased by at least 2.0 in only 1. These observations reveal short-term improvement in thallium-201 myocardial perfusion with nifedipine in patients with progressive systemic sclerosis. The results are consistent with a potentially reversible abnormality of coronary vasomotion in this disorder, but the long-term therapeutic effects of nifedipine remain to be determined

Renal perfusion image using harmonic ultrasound with microbble contrast agent: preliminary study

International Nuclear Information System (INIS)

Kim, Jung Hoon; Choi, Jae Ho; Han, Dong Chul; Lee, Hi Bahl; Choi, Deuk Lin; Eun, Hyo Won; Lee, Hun Jae

2003-01-01

To compare, in terms of their feasibility and normal range, 99m Tc-DTPA renal perfusion imaging and renal perfusion imaging using harmonic ultrasound (US) with a microbubble contrast agent for the evaluation of renal perfusion after renal transplantation. During a six-month period, thirty patients who had received a renal transplant underwent both 99m Tc-DTPA renal perfusion imaging and renal perfusion imaging using harmonic US with a microbubble contrast agent. Sonographic renal perfusion images were obtained before and after a bolus injection of the microbubble contrast agent Levovist TM (SH U 5084; Schering AG, Berlin, Germany) every 3 seconds for 3 minutes. Sonographic renal perfusion images were converted into a renal perfusion curve by a computer program and T peak of the curve thus obtained was compared with that of the 99m Tc-DTPA curve. Average T peak of the 99m Tc-DTPA renal perfusion curve was 16.2 seconds in the normal group and 39.6 seconds in the delayed perfusion group, while average T peak of the sonographic renal perfusion curve was 23.7 seconds and 46.2 seconds, respectively. T peak of the sonographic renal perfusion curve showed a good correlation with that of the 99m Tc-DTPA curve (correlation coefficient=0.8209; p=0.0001). The cut-off value of T peak of the sonographic renal perfusion curve was 35 seconds (sensitivity=90%, specificity=95%). In patients who have received a renal transplant, the findings of renal perfusion imaging using harmonic US with a microbubble contrast agent show close correlation with those of 99m Tc-DTPA renal perfusion imaging. The optimal cut-off value of T peak of the sonographic renal perfusion curve was 35 seconds

Prevalence and predictors of an abnormal stress myocardial perfusion study in asymptomatic patients with type 2 diabetes mellitus

International Nuclear Information System (INIS)

Scholte, Arthur J.H.A.; Schuijf, Joanne D.; Wall, Ernst E. van der; Bax, Jeroen J.; Kharagjitsingh, Antje V.; Dibbets-Schneider, Petra; Stokkel, Marcel P.

2009-01-01

The purpose of this study was to evaluate the prevalence of an abnormal stress myocardial perfusion study in a cohort of truly asymptomatic patients with type 2 diabetes mellitus using myocardial perfusion imaging by means of single photon emission computed tomography (SPECT). Secondly, we determined which clinical characteristics may predict an abnormal stress myocardial perfusion study in this population. A total of 120 asymptomatic patients (mean age 53±10 years) with type 2 diabetes mellitus and one or more risk factors for coronary artery disease were prospectively recruited from an outpatient diabetes clinic. All patients underwent myocardial perfusion imaging by means of adenosine 99m Tc sestamibi SPECT. Images were evaluated for the presence of perfusion abnormalities as well as other nonperfusion abnormalities that may indicate extensive ischaemia, including left ventricular dysfunction (defined as a left ventricular ejection fraction <45%), transient ischaemic dilatation and adenosine-induced ST segment depression. Multivariable analysis was performed using a backward selection strategy to identify potential predictors for an abnormal stress myocardial perfusion study. Finally, all patients were followed up for 12 months to determine the occurrence of cardiovascular events: (1) cardiac death, (2) nonfatal myocardial infarction, (3) unstable angina requiring hospitalization, (4) revascularization, or (5) stroke. Of the 120 patients, 40 (33%) had an abnormal stress study, including myocardial perfusion abnormalities in 30 patients (25%). In 10 patients (8%), indicators of extensive (possibly balanced ischaemia) were observed in the absence of abnormal perfusion. The multivariable analysis identified current smoking, duration of diabetes and the cholesterol/high-density lipoprotein (HDL) ratio as independent predictors of an abnormal stress study. During a follow-up period of 12 months six patients (5%) had a cardiovascular event. The current study revealed

Prevalence and predictors of an abnormal stress myocardial perfusion study in asymptomatic patients with type 2 diabetes mellitus

Energy Technology Data Exchange (ETDEWEB)

Scholte, Arthur J.H.A.; Schuijf, Joanne D.; Wall, Ernst E. van der; Bax, Jeroen J. [Leiden University Medical Center, Department of Cardiology, Albinusdreef 2, PO Box 9600, Leiden (Netherlands); Kharagjitsingh, Antje V. [Medisch Centrum Haaglanden, Department of Internal Medicine, The Hague (Netherlands); Dibbets-Schneider, Petra; Stokkel, Marcel P. [Leiden University Medical Center, Department of Nuclear Medicine, Leiden (Netherlands)

2009-04-15

The purpose of this study was to evaluate the prevalence of an abnormal stress myocardial perfusion study in a cohort of truly asymptomatic patients with type 2 diabetes mellitus using myocardial perfusion imaging by means of single photon emission computed tomography (SPECT). Secondly, we determined which clinical characteristics may predict an abnormal stress myocardial perfusion study in this population. A total of 120 asymptomatic patients (mean age 53{+-}10 years) with type 2 diabetes mellitus and one or more risk factors for coronary artery disease were prospectively recruited from an outpatient diabetes clinic. All patients underwent myocardial perfusion imaging by means of adenosine {sup 99m}Tc sestamibi SPECT. Images were evaluated for the presence of perfusion abnormalities as well as other nonperfusion abnormalities that may indicate extensive ischaemia, including left ventricular dysfunction (defined as a left ventricular ejection fraction <45%), transient ischaemic dilatation and adenosine-induced ST segment depression. Multivariable analysis was performed using a backward selection strategy to identify potential predictors for an abnormal stress myocardial perfusion study. Finally, all patients were followed up for 12 months to determine the occurrence of cardiovascular events: (1) cardiac death, (2) nonfatal myocardial infarction, (3) unstable angina requiring hospitalization, (4) revascularization, or (5) stroke. Of the 120 patients, 40 (33%) had an abnormal stress study, including myocardial perfusion abnormalities in 30 patients (25%). In 10 patients (8%), indicators of extensive (possibly balanced ischaemia) were observed in the absence of abnormal perfusion. The multivariable analysis identified current smoking, duration of diabetes and the cholesterol/high-density lipoprotein (HDL) ratio as independent predictors of an abnormal stress study. During a follow-up period of 12 months six patients (5%) had a cardiovascular event. The current study

Myocardial perfusion in type 2 diabetes with left ventricular hypertrophy

DEFF Research Database (Denmark)

Hesse, Birger; Meyer, Christian; Nielsen, Flemming S

2004-01-01

The purpose of this study was to assess whether acute angiotensin-converting enzyme (ACE) inhibition would improve myocardial perfusion and perfusion reserve in a subpopulation of normotensive patients with diabetes and left ventricular hypertrophy (LVH), both independent risk factors of coronary...... disease. Using positron emission tomography (PET), we investigated the response of regional myocardial perfusion to acute ACE inhibition with i.v. infusion of perindoprilat (vs saline infusion as control, minimum interval 3 days) in 12 diabetic patients with LVH. Myocardial perfusion was quantified...... with controls, maximal perfusion was reduced in patients (1.8+/-0.6 vs 2.5+/-1.0 ml min(-1) g(-1); P2.7+/-1.0 vs 3.6+/-1.3; P=0.059). During perindoprilat infusion, myocardial perfusion reserve in patients increased to 3.9+/-0.9 ( P

FROG INTESTINAL PERFUSION TO EVALUATE DRUG PERMEABILITY: APPLICATION TO P-gp AND CYP3A4 SUBSTRATES

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Neelima eYerasi

2015-07-01

Full Text Available AbstractTo evaluate the reliability of using in situ frog intestinal perfusion technique for permeability assessment of carrier transported drugs which are also substrates for CYP enzymes. Single Pass Intestinal Perfusion (SPIP studies were performed in frogs of the species Rana tigrina using established method for rats with some modifications after inducing anesthesia. Effective permeability coefficient (Peff of losartan and midazolam was calculated in the presence and absence of inhibitors using the parallel-tube model. Peff of losartan when perfused alone was found to be 0.427 ± 0.27×10-4cm/s and when it was co-perfused with inhibitors, significant change in Peff was observed. Peff of midazolam when perfused alone was found to be 2.03 ± 0.07 × 10-4cm/s and when it was co-perfused with inhibitors, no significant change in Peff was observed. Comparison of Peff calculated in frog with that of other available models and also humans suggested that the Peff values are comparable and reflected well with human intestinal permeability. It is possible to determine the Peff value for compounds which are dual substrates of P-gp and CYP3A4 using in situ frog intestinal perfusion technique. The calculated Peff values correlated well with reported Peff values of probe drugs. comparison of the Peff value of losartan obtained with that of reported human’s Peff and Caco 2 cell data, and comparison of the Peff value of midazolam with that of reported rat’s Peff, we could conclude that SPIP from model can be reliably used in preclinical studies for permeability estimation. This model may represent a valuable alternative to the low speed and high cost of conventional animal models (typically rodents for the assessment of intestinal permeability.

Myocardial performance and perfusion during exercise in patients with coronary artery disease caused by Kawasaki disease

International Nuclear Information System (INIS)

Paridon, S.M.; Ross, R.D.; Kuhns, L.R.; Pinsky, W.W.

1990-01-01

For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion

The circadian rhythm induced by the heterogeneous network structure of the suprachiasmatic nucleus

Science.gov (United States)

Gu, Changgui; Yang, Huijie

2016-05-01

In mammals, the master clock is located in the suprachiasmatic nucleus (SCN), which is composed of about 20 000 nonidentical neuronal oscillators expressing different intrinsic periods. These neurons are coupled through neurotransmitters to form a network consisting of two subgroups, i.e., a ventrolateral (VL) subgroup and a dorsomedial (DM) subgroup. The VL contains about 25% SCN neurons that receive photic input from the retina, and the DM comprises the remaining 75% SCN neurons which are coupled to the VL. The synapses from the VL to the DM are evidently denser than that from the DM to the VL, in which the VL dominates the DM. Therefore, the SCN is a heterogeneous network where the neurons of the VL are linked with a large number of SCN neurons. In the present study, we mimicked the SCN network based on Goodwin model considering four types of networks including an all-to-all network, a Newman-Watts (NW) small world network, an Erdös-Rényi (ER) random network, and a Barabási-Albert (BA) scale free network. We found that the circadian rhythm was induced in the BA, ER, and NW networks, while the circadian rhythm was absent in the all-to-all network with weak cellular coupling, where the amplitude of the circadian rhythm is largest in the BA network which is most heterogeneous in the network structure. Our finding provides an alternative explanation for the induction or enhancement of circadian rhythm by the heterogeneity of the network structure.

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

DEFF Research Database (Denmark)

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

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

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

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Weininger, Markus [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC (United States); Ramachandra, Ashok [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Rowe, Garrett W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Henzler, Thomas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

2012-12-15

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

International Nuclear Information System (INIS)

Weininger, Markus; Schoepf, U. Joseph; Ramachandra, Ashok; Fink, Christian; Rowe, Garrett W.; Costello, Philip; Henzler, Thomas

2012-01-01

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

International Nuclear Information System (INIS)

Talakic, Emina; Schoellnast, Helmut; Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut; Stauber, Rudolf; Quehenberger, Franz

2017-01-01

To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p < 0.05) between SAF and HVPG, and -0.68 (p < 0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. (orig.)

CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

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Talakic, Emina; Schoellnast, Helmut [Medical University of Graz, Division of General Radiology, Department of Radiology, Graz (Austria); Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut [Medical University of Graz, Department of Surgery, Division of Transplantation Surgery, Graz (Austria); Stauber, Rudolf [Medical University of Graz, Department of Internal Medicine, Division of Gastoenterology and Hepatology, Graz (Austria); Quehenberger, Franz [Medical University of Graz, Institute for Medical Informatics, Statistics and Documentation, Graz (Austria)

2017-10-15

To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p < 0.05) between SAF and HVPG, and -0.68 (p < 0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. (orig.)

Hemodynamic study on liver cirrhosis: clinical application of CT perfusion imaging

International Nuclear Information System (INIS)

Jiang Li; Yang Jianyong; Xie Hongbo; Yang Xufeng; Yan Chaogui; Li Ziping; Zeng Fang

2004-01-01

Objective: To estimate hepatic perfusion parameters with helical CT, and to study the relationship between hepatic perfusion parameters and the severity of liver cirrhosis. Methods: Dynamic single-section computed tomography (CT) of the liver was performed in 40 participants, including 27 patients with liver cirrhosis and 13 patients without liver disease (control subjects). CT scans were obtained at a single level to include the liver, spleen, aorta, and portal vein. On each CT scan, the attenuation of these organs was measured in regions of interest to provide time-density curves. The arterial, portal venous, and total perfusion of the liver and the hepatic perfusion index were assessed. Results: In the control group, hepatic arterial perfusion, portal venous perfusion, and total hepatic perfusion were (0.2823 ± 0.0969) ml·min -1 ·ml -1 , (1.1788 ± 0.4004) ml·min -1 ·ml -1 , and (1.4563 ± 0.4439) ml·min -1 ·ml -1 , respectively. Hepatic perfusion index was (19.73 ±5.81)%. These hepatic perfusion parameters correlated significantly with the severity of liver cirrhosis. Hepatic arterial perfusion decreased in Child A and B cirrhotic patients [ (0.1685 ± 0.1068) ml·min -1 ·ml -1 and (0.1921 ± 0.0986) ml·min -1 ·ml -1 , respectively]. Comparing to Child A and B cirrhotic patients, hepatic arterial perfusion in Child C cirrhotic patients [(0.3072 · 0.1145) ml·min -1 ·ml -1 ] raised significantly. Portal venous perfusion decreased significantly in Child B and C cirrhotic patients [(0.6331±0.2070) ml·min -1 ·ml -1 and (0.5702 ± 0.3562) ml·min -1 ·ml -1 , respectively]. Total hepatic blood flow reduced markedly in Child B and C cirrhotic patients [(0.8252 ± 0.2952) ml·min -1 ·ml -1 and (0.8774 ± 0.4118) ml·min -1 ·ml -1 , respectively]. Hepatic perfusion index increased in Child C cirrhotic patients (37.48 ± 16.65)%. Conclusion: Dynamic single-section CT showed potential in quantifying hepatic perfusion parameters, and hepatic perfusion

Light induced heterogeneous ozone processing on the pesticides adsorbed on silica particles

Science.gov (United States)

Socorro, J.; Désert, M.; Quivet, E.; Gligorovski, S.; Wortham, H.

2013-12-01

In France, in 2010, the sales of pesticides reached 1.8 billion euros for 61 900 tons of active ingredients, positioning France as a first European consumer of pesticides, as reported by the European Crop Protection Association. About 19 million hectares of crops are sprayed annually with pesticides, i.e., 35% of the total surface area of France. This corresponds to an average pesticide dose of 3.2 kg ha-1. The consumption of herbicide and fungicide is favoured in comparison to the use of insecticides in France and the other European countries, as well. The partitioning of pesticides between the gas and particulate phases influences the atmospheric fate of these compounds such as their photo-chemical degradation. There is much uncertainty concerning the behavior of the pesticides in the atmosphere. Especially, there is a gap of knowledge concerning the degradation of the pesticides induced by heterogeneous reactions in absence and especially in presence of solar light. Considering that most of the pesticides currently used are semi-volatile, it is of crucial importance to investigate the heterogeneous reactivity of particulate pesticides with light and with atmospheric oxidants such as ozone and OH radical. The aim of the present work is to evaluate the light induced heterogeneous ozonation of suspended pesticide particles. 8 pesticides (cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin and tetraconazole) were chosen for their physico-chemical properties and their concentration levels in the PACA (Région Provence-Alpes-Côte d'Azur) region, France. Silica particles with well-known properties were chosen as model particles of atmospheric relevance. Kinetic rate constants were determined to allow estimate the atmospheric lifetimes relating to ozone. The rate constants were determined as follows: k = (6.6 × 0.2) 10-19, (7.2 × 0.3) 10-19, (5.1 × 0.5) 10-19, (3.9 × 0.3) 10-19 [cm3 molecules-1 s-1] for Cyprodinil

Study of lung perfusion in colagenosis

Energy Technology Data Exchange (ETDEWEB)

Macedo de Carvalho, A C; Calegaro, J U.M. [Fundacao Hospitalar do Distrito Federal, Distrito Federal (Brazil). Unidade de Medicina Nuclear

1982-07-01

The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized.

Study of lung perfusion in colagenosis

International Nuclear Information System (INIS)

Macedo de Carvalho, A.C.; Calegaro, J.U.M.

1982-01-01

The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized. (author) [es

MR-based assessment of pulmonary ventilation-perfusion in animal models

International Nuclear Information System (INIS)

Yang Jian; Wan Mingxi; Guo Youmin

2003-01-01

Objective: To show the feasibility and value in the diagnosis of airway obstruction and pulmonary embolism with MR oxygen-enhanced ventilation combined with pulmonary perfusion imaging. Methods: Eight canines were implemented for peripheral pulmonary embolism by intravenous injection of gelfoam granules at pulmonary segmental arterial level, and five of them were formed airway obstruction models by inserting self-made balloon catheter at second-bronchia. The oxygen-enhanced MR ventilation imaging was introduced by subtracting the images of pre- and post- inhaled pure oxygen. The MR pulmonary perfusion imaging was achieved by the first-pass contrast agent method. Moreover, the manifestation of MR ventilation and perfusion imaging was observed and contradistinguished with that of general pathologic anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography. Results: The manifestations of airway obstruction regions in MR ventilation and perfusion imaging were matched, but those of pulmonary embolism regions were dismatched. The defect range of airway obstruction in MR ventilation image was smaller than that in ventilation scintigraphy. The abnormal perfusion regions of pulmonary embolism were divided into defect regions and reduce regions based on the time courses of signal intensity changes. The sensitivity and specificity of diagnosis on pulmonary embolism by MR ventilation combined with perfusion technique were 75.0% and 98.1%. The diagnostic results were in good coherence with ventilation-perfusion scintigraphy and pulmonary angiography (K=0.743, 0.899). Conclusion: The MR oxygen-enhanced ventilation combined with pulmonary perfusion imaging can be used to diagnose the airway and vascular abnormity in lung. This technique resembles the ventilation-perfusion scintigraphy. It can provide quantitative functional information and better spatial and temporal resolution, and possesses the value of clinical application

Patient-specific coronary blood supply territories for quantitative perfusion analysis

Science.gov (United States)

Zakkaroff, Constantine; Biglands, John D.; Greenwood, John P.; Plein, Sven; Boyle, Roger D.; Radjenovic, Aleksandra; Magee, Derek R.

2018-01-01

Abstract Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis. PMID:29392098

Extreme Threshold Failures Within a Heterogeneous Elastic Thin Sheet and the Spatial-Temporal Development of Induced Seismicity Within the Groningen Gas Field

Science.gov (United States)

Bourne, S. J.; Oates, S. J.

2017-12-01

Measurements of the strains and earthquakes induced by fluid extraction from a subsurface reservoir reveal a transient, exponential-like increase in seismicity relative to the volume of fluids extracted. If the frictional strength of these reactivating faults is heterogeneously and randomly distributed, then progressive failures of the weakest fault patches account in a general manner for this initial exponential-like trend. Allowing for the observable elastic and geometric heterogeneity of the reservoir, the spatiotemporal evolution of induced seismicity over 5 years is predictable without significant bias using a statistical physics model of poroelastic reservoir deformations inducing extreme threshold frictional failures of previously inactive faults. This model is used to forecast the temporal and spatial probability density of earthquakes within the Groningen natural gas reservoir, conditional on future gas production plans. Probabilistic seismic hazard and risk assessments based on these forecasts inform the current gas production policy and building strengthening plans.

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

Science.gov (United States)

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%.

Effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

Energy Technology Data Exchange (ETDEWEB)

Claiborne, J.B. (Miami Univ., Coral Gables, FL (USA)); Evans, D.H. (Mt. Desert Island Biological Laboratory, Salsbury Cove, ME, USA)

1981-06-01

In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of /sup 22/Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro /sup 36/Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion.

Magnetic Resonance Imaging of Ventilation and Perfusion in the Lung

Science.gov (United States)

Prisk, Gordon Kim (Inventor); Hopkins, Susan Roberta (Inventor); Buxton, Richard Bruce (Inventor); Pereira De Sa, Rui Carlos (Inventor); Theilmann, Rebecca Jean (Inventor); Cronin, Matthew Vincent (Inventor)

2017-01-01

Methods, devices, and systems are disclosed for implementing a fully quantitative non-injectable contrast proton MRI technique to measure spatial ventilation-perfusion (VA/Q) matching and spatial distribution of ventilation and perfusion. In one aspect, a method using MRI to characterize ventilation and perfusion in a lung includes acquiring an MR image of the lung having MR data in a voxel and obtaining a breathing frequency parameter, determining a water density value, a specific ventilation value, and a perfusion value in at least one voxel of the MR image based on the MR data and using the water density value to determine an air content value, and determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency.

Whole-brain dynamic CT angiography and perfusion imaging

Energy Technology Data Exchange (ETDEWEB)

Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

2011-06-15

The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

Cerebral perfusion computed tomography deconvolution via structure tensor total variation regularization

Energy Technology Data Exchange (ETDEWEB)

Zeng, Dong; Zhang, Xinyu; Bian, Zhaoying, E-mail: zybian@smu.edu.cn, E-mail: jhma@smu.edu.cn; Huang, Jing; Zhang, Hua; Lu, Lijun; Lyu, Wenbing; Feng, Qianjin; Chen, Wufan; Ma, Jianhua, E-mail: zybian@smu.edu.cn, E-mail: jhma@smu.edu.cn [Department of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, China and Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong 510515 (China); Zhang, Jing [Department of Radiology, Tianjin Medical University General Hospital, Tianjin 300052 (China)

2016-05-15

Purpose: Cerebral perfusion computed tomography (PCT) imaging as an accurate and fast acute ischemic stroke examination has been widely used in clinic. Meanwhile, a major drawback of PCT imaging is the high radiation dose due to its dynamic scan protocol. The purpose of this work is to develop a robust perfusion deconvolution approach via structure tensor total variation (STV) regularization (PD-STV) for estimating an accurate residue function in PCT imaging with the low-milliampere-seconds (low-mAs) data acquisition. Methods: Besides modeling the spatio-temporal structure information of PCT data, the STV regularization of the present PD-STV approach can utilize the higher order derivatives of the residue function to enhance denoising performance. To minimize the objective function, the authors propose an effective iterative algorithm with a shrinkage/thresholding scheme. A simulation study on a digital brain perfusion phantom and a clinical study on an old infarction patient were conducted to validate and evaluate the performance of the present PD-STV approach. Results: In the digital phantom study, visual inspection and quantitative metrics (i.e., the normalized mean square error, the peak signal-to-noise ratio, and the universal quality index) assessments demonstrated that the PD-STV approach outperformed other existing approaches in terms of the performance of noise-induced artifacts reduction and accurate perfusion hemodynamic maps (PHM) estimation. In the patient data study, the present PD-STV approach could yield accurate PHM estimation with several noticeable gains over other existing approaches in terms of visual inspection and correlation analysis. Conclusions: This study demonstrated the feasibility and efficacy of the present PD-STV approach in utilizing STV regularization to improve the accuracy of residue function estimation of cerebral PCT imaging in the case of low-mAs.

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

Science.gov (United States)

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

2014-01-01

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

Development and use of a new perfusion technique to study glucose metabolism of the aortic wall in normal and alloxan-diabetic rabbits

International Nuclear Information System (INIS)

Brown, B.J.M.

1985-01-01

This study investigated (1) possible alterations in glucose uptake and utilization in the perfused, normal, and diabetic vascular wall of rabbits and (2) the effects thereon of insulin and exogenous glucose concentration. Part I involved development and characterization of an in vitro perfusion technique that closely reproduced predetermined in vivo conditions of aortic blood flow, arterial blood pressure, heart rate and pulse pressure. The responsiveness of the preparation to vasoactive agents was assessed with concentrations of norepinephrine (NE) from 10 -9 to 10 -4 M. In Part II, the effects of NE-induced tension development on glucose metabolism were determined by perfusion with oxygenated physiological salt solution (PSS) containing 7 mM glucose and tracer amounts of uniformly labeled 14 C-glucose. Aortas from 8 week-diabetic rabbits were perfused under similar conditions employing a NE infusion in the presence or absence of insulin (150 uU/ml) and variable levels of glucose. Effects of NE-induced tension development include an apparent increase (39%) in glucose uptake and a twofold increase in 14 CO 2 and lactate production. Aortas from diabetic rabbits perfused with PSS containing 7 mM glucose demonstrated marked decreases in glucose uptake (74%), 14 CO 2 (68%), lactate (30%), total tissue glycogen (75%) and labeled tissue phospholipids (70%). Insulin or elevation of exogenous glucose to 25 mM (diabetic levels) normalized glucose uptake, but had differential effects on the pattern of substrate utilization. The marked alterations of glucose metabolism in the diabetic state may contribute to the functional changes observed in diabetic blood vessels

Influence of angiographic collateral circulation on myocardial perfusion in patients with chronic total occlusion of a single coronary artery and no prior myocardial infarction.

Science.gov (United States)

Aboul-Enein, Fatma; Kar, Saibal; Hayes, Sean W; Sciammarella, Maria; Abidov, Aiden; Makkar, Raj; Friedman, John D; Eigler, Neal; Berman, Daniel S

2004-06-01

The functional role of various angiographic grades for coronary collaterals remains controversial. The aim of this study was to assess the influence of the Rentrop angiographic grading of coronary collaterals on myocardial perfusion in patients with single-vessel chronic total occlusion (CTO) and no prior myocardial infarction (MI). The study included 56 patients with single-vessel CTO and no prior MI who underwent rest-stress myocardial perfusion SPECT and coronary angiography within 6 mo. All patients had angiographic evidence of coronary collaterals. Patients were divided according to the Rentrop classification: Group I had grade 1 or 2 (n = 25) and group II had grade 3 collaterals (n = 31). Group I had a higher frequency of resting regional wall motion abnormalities on left ventriculography (52.6% vs. 19.2% [P = 0.019]). The mean perfusion scores of the overall population showed severe and extensive stress perfusion defects (summed stress score of 14.1 +/- 7.1 and summed difference score of 12.9 +/- 6.9) but minimal resting perfusion defects (summed rest score of 1.0 +/- 2.7). No perfusion scores differed between the 2 groups. The perfusion findings suggested that chronic stunning rather than hibernation is the principal cause of regional wall motion abnormalities in these patients. In the setting of single-vessel CTO and no prior MI, coronary collaterals appear to protect against resting perfusion defects. Excellent angiographic collaterals may prevent resting regional wall motion abnormalities but do not appear to protect against stress-induced perfusion defects.

Quality assessment of a placental perfusion protocol

DEFF Research Database (Denmark)

Mathiesen, Line; Mose, Tina; Mørck, Thit Juul

2010-01-01

mlh(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success rate...

Dual energy CT for the assessment of lung perfusion-Correlation to scintigraphy

International Nuclear Information System (INIS)

Thieme, Sven F.; Becker, Christoph R.; Hacker, Marcus; Nikolaou, Konstantin; Reiser, Maximilian F.; Johnson, Thorsten R.C.

2008-01-01

Purpose of this study was to determine the diagnostic value of dual energy CT in the assessment of pulmonary perfusion with reference to pulmonary perfusion scintigraphy. Thirteen patients received both dual energy CT (DECT) angiography (Somatom Definition, Siemens) and ventilation/perfusion scintigraphy. Median time between scans was 3 days (range, 0-90). DECT perfusion maps were generated based on the spectral properties of iodine. Two blinded observes assessed DECT angiograms, perfusion maps and scintigrams for presence and location of perfusion defects. The results were compared by patient and by segment, and diagnostic accuracy of DECT perfusion imaging was calculated regarding scintigraphy as standard of reference. Diagnostic accuracy per patient showed 75% sensitivity, 80% specificity and a negative predictive value of 66%. Sensitivity per segment amounted to 83% with 99% specificity, with 93% negative predictive value. Peripheral parts of the lungs were not completely covered by the 80 kVp detector in 85% of patients. CTA identified corresponding emboli in 66% of patients with concordant perfusion defects in DECT and scintigraphy. Dual energy CT perfusion imaging is able to display pulmonary perfusion defects with good agreement to scintigraphic findings. DECT can provide a pulmonary CT angiogram, high-resolution morphology of the lung parenchyma and perfusion information in one single exam

Dual energy CT for the assessment of lung perfusion-Correlation to scintigraphy

Energy Technology Data Exchange (ETDEWEB)

Thieme, Sven F.; Becker, Christoph R. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany); Hacker, Marcus [Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich (Germany); Nikolaou, Konstantin; Reiser, Maximilian F. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany); Johnson, Thorsten R.C. [Department of Clinical Radiology, Ludwig-Maximilians-University of Munich (Germany)], E-mail: thorsten.johnson@med.uni-muenchen.de

2008-12-15

Purpose of this study was to determine the diagnostic value of dual energy CT in the assessment of pulmonary perfusion with reference to pulmonary perfusion scintigraphy. Thirteen patients received both dual energy CT (DECT) angiography (Somatom Definition, Siemens) and ventilation/perfusion scintigraphy. Median time between scans was 3 days (range, 0-90). DECT perfusion maps were generated based on the spectral properties of iodine. Two blinded observes assessed DECT angiograms, perfusion maps and scintigrams for presence and location of perfusion defects. The results were compared by patient and by segment, and diagnostic accuracy of DECT perfusion imaging was calculated regarding scintigraphy as standard of reference. Diagnostic accuracy per patient showed 75% sensitivity, 80% specificity and a negative predictive value of 66%. Sensitivity per segment amounted to 83% with 99% specificity, with 93% negative predictive value. Peripheral parts of the lungs were not completely covered by the 80 kVp detector in 85% of patients. CTA identified corresponding emboli in 66% of patients with concordant perfusion defects in DECT and scintigraphy. Dual energy CT perfusion imaging is able to display pulmonary perfusion defects with good agreement to scintigraphic findings. DECT can provide a pulmonary CT angiogram, high-resolution morphology of the lung parenchyma and perfusion information in one single exam.

Cerebral perfusion imaging in HIV positive patients

International Nuclear Information System (INIS)

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

1998-01-01

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

Automatic Detection of Myocardial Boundaries in MR Cardio Perfusion Images

NARCIS (Netherlands)

Spreeuwers, Luuk; Breeuwer, Marcel

2001-01-01

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

[Myokard-Perfusions-SPECT. Myocardial perfusion SPECT - Update S1 guideline].

Science.gov (United States)

Lindner, Oliver; Bengel, Frank; Burchert, Wolfgang; Dörr, Rolf; Hacker, Marcus; Schäfer, Wolfgang; Schäfers, Michael A; Schmidt, Matthias; Schwaiger, Markus; Vom Dahl, Jürgen; Zimmermann, Rainer

2017-08-14

The S1 guideline for myocardial perfusion SPECT has been published by the Association of the Scientific Medical Societies in Germany (AWMF) and is valid until 2/2022. This paper is a short summary with comments on all chapters and subchapters wich were modified and amended.

PET imaging of cerebral perfusion and oxygen metabolism in stroke

Energy Technology Data Exchange (ETDEWEB)

Pointon, O.; Yasaka, M.; Berlangieri, S.U.; Newton, M.R.; Thomas, D.L.; Chan, C.G.; Egan, G.F.; Tochon-Danguy, H.J.; O``Keefe, G.; Donnan, G.A.; McKay, W.J. [Austin Hospital, Melbourne, VIC (Australia). Centre for PET and Depts of Nuclear Medicine and Neurology

1998-03-01

Full text: Stroke remains a devastating clinical event with few therapeutic options. In patients with acute stroke, we studied the cerebral perfusion and metabolic patterns with {sup 15}O-CO{sub 2} or H{sub 2}O and {sup 15}O-O{sub 2} positron emission tomography and correlated these findings to the clinical background. Forty three patients underwent 45 studies 0-23 days post-stroke (mean 7 days). Fifteen patients showed luxury perfusion (Group A), 10 had matched low perfusion and metabolism (B) and 3 showed mixed pattern including an area of misery perfusion (C). Seventeen showed no relevant abnormality (D) and there were no examples of isolated misery perfusion. Twelve of the 15 in Group A had either haemorrhagic transformation on CT, re-opening on angiography, or a cardioembolic mechanism. In contrast only 5/10 in Group B, 0/3 in Group C and 2/17 in Group D had these features. Although 7/10 in group B had moderate or large size infarcts on CT the incidence of haemorrhagic transformation was low (2/10) and significant carotid stenoses were more common in those studied (5/8) compared with the other groups. Misery perfusion was not seen beyond five days. Thus, luxury perfusion seems to be related to a cardio-embolic mechanism or reperfusion. Matched low perfusion and metabolism was associated with a low rate of haemorrhagic transformation despite a high incidence of moderate to large size infarcts. Misery perfusion is an early phenomenon in the evolution of ischaemic stroke.

Computed Tomography (CT) Perfusion in Abdominal Cancer

DEFF Research Database (Denmark)

Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

2013-01-01

Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...

Perfusion CT in childhood stroke—Initial observations and review of the literature

Energy Technology Data Exchange (ETDEWEB)

Zebedin, D., E-mail: doris.zebedin@medunigraz.at [Division of Pediatric Radiology, Department of Radiology, University Hospital LKH Graz (Austria); Sorantin, E.; Riccabona, M. [Division of Pediatric Radiology, Department of Radiology, University Hospital LKH Graz (Austria)

2013-07-15

Introduction: To report the preliminary results of contrast-enhanced perfusion multi-detector CT for diagnoses of perfusion disturbances in children with clinical suspicion of stroke. Patients and methods: Within the last two years emergency perfusion CT was performed in ten children (age: 8–17 years, male:female = 3:7) for assessment of suspected childhood stroke. These intracranial perfusion CT, intracranial CT-digital subtraction angiography (CT-DSA) and extracranial CT-angiography (CTA) studies were retrospectively reviewed and compared with MRI, follow-up CT, catheter angiography and final clinical diagnosis. The total dose length product (DLP) for the entire examination was recorded. The image quality of perfusion CT-maps, CT-DSA and CTA were evaluated with a subjective three-point scale ranging from very good to non-diagnostic image quality rating perfusion disturbance, intracranial peripheral vessel depiction, and motion- or streak artifacts. Results: In nine of ten children perfusion CT showed no false positive or false negative results. In one of ten children suffering from migraine focal hypo-perfusion was read as perfusion impairment potentially indicating early stroke, but MRI and MRA follow-up were negative. Overall, perfusion-CT with CT-DSA was rated very good in 80% of cases for the detection of perfusion disturbances and vessel anatomy. Conclusions: In comparison to standard CT, contrast-enhanced perfusion CT improves CTs’ diagnostic capability in the emergency examination of children with a strong suspicion of ischemic cerebral infarction.

Myocardial perfusion imaging with dual energy CT

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

2016-10-15

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

Comparison of Intrahepatic and Pancreatic Perfusion on Fusion Images Using a Combined SPECT/CT System and Assessment of Efficacy of Combined Continuous Arterial Infusion and Systemic Chemotherapy in Advanced Pancreatic Carcinoma

International Nuclear Information System (INIS)

Ikeda, Osama; Tamura, Yoshitaka; Nakasone, Yutaka; Shiraishi, Shinya; Kawanaka, Kouichi; Tomiguchi, Seiji; Yamashita, Yasuyuki; Takamori, Hiroshi; Kanemitsu, Keiichiro; Baba, Hideo

2007-01-01

Purpose. The purpose of this study was to compare intrahepatic and pancreatic perfusion on fusion images using a combined single-photon emission computed tomography (SPECT)/CT system and to evaluate the efficacy of combined continuous transcatheter arterial infusion (CTAI) and systemic chemotherapy in the treatment of advanced pancreatic carcinoma. Materials and Methods. CTAI was performed in 33 patients (22 men, 11 women; age range, 35-77 years; mean age, 60 years) with stage IV pancreatic cancer with liver metastasis. The reservoir was transcutaneously implanted with the help of angiography. The systemic administration of gemcitabine was combined with the infusion of 5-fluorouracil via the reservoir. In all patients we obtained fusion images using a combined SPECT/CT system. Pancreatic perfusion on fusion images was classified as perfusion presence or as perfusion absent in the pancreatic cancer. Using WHO criteria we recorded the tumor response after 3 months on multislice helical CT scans. Treatment effects were evaluated based on the pancreatic cancer, liver metastasis, and factors such as intrahepatic and pancreatic perfusion on fusion images. For statistical analysis we used the chi-square test; survival was evaluated by the Kaplan Meier method (log-rank test). Results. On fusion images, pancreatic and intrahepatic perfusion was recorded as hot spot and as homogeneous distribution, respectively, in 18 patients (55%) and as cold spot and heterogeneous distribution, respectively, in 15 (45%). Patients with hot spot in the pancreatic tumor and homogeneous distribution in the liver manifested better treatment results (p < 0.05 and p < 0.01, respectively). Patients with hot spot both in the pancreatic cancer and in the liver survived longer than those with cold spot in the pancreatic cancer and heterogeneous distribution in the liver (median ± SD, 16.0 ± 3.7 vs. 8.0 ± 1.4 months; p < 0.05). Conclusions. We conclude that in patients with advanced pancreatic

Ventilation-perfusion distribution in normal subjects.

Science.gov (United States)

Beck, Kenneth C; Johnson, Bruce D; Olson, Thomas P; Wilson, Theodore A

2012-09-01

Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.

The effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

International Nuclear Information System (INIS)

Claiborne, J.B.; Evans, D.H.

1981-01-01

In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of 22 Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro 36 Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion. (Auth.)

Kidney in potassium depletion. II. K+ handling by the isolated perfused rat kidney

International Nuclear Information System (INIS)

Hayashi, M.; Katz, A.I.

1987-01-01

In a companion paper the authors reported a large increment in Na + -K + -ATPase activity and [ 3 H]ouabain binding the inner stripe of outer medullary collecting tubules from K-depleted rats. To test the hypothesis that the increased number of Na + -K + pumps in these animals may be involved in potassium reabsorption they examined the effect of ouabain on K excretion by isolated, perfused kidneys from rats fed a K-free diet for 3 wk. Kidneys from K-depleted rats retain potassium avidly, both the fractional (FE/sub K/) and absolute K excretion being approximately fivefold lower than in control kidneys. Ouabain (5 mM) increased FE/sub K/ in kidneys from each K-depleted rat; similar results were obtained when kidneys were perfused with low and high potassium concentrations. In contrast, ouabain produced a variable effect in control kidneys, that depended on the perfusate potassium concentration. In K-depleted rats amiloride did not significantly alter K excretion and did not block the ouabain-induced kaliuresis, suggesting that the latter is not due to enhanced secretion secondary to increased distal fluid delivery. These results provide evidence for ouabain-sensitive potassium reabsorption in kidneys of chronically K-depleted rats, and suggest an explanation for the increased Na + -K + -ATPase observed in such animals

Nuclear magnetic resonance studies of intracellular ions in perfused from heart

International Nuclear Information System (INIS)

Burnstein, D.; Fossel, E.T.

1987-01-01

Intracellular sodium, potassium, and lithium were observed in a perfused frog heart by nuclear magnetic resonance (NMR) spectroscopy. A perfusate buffer containing the shift reagent, dysprosium tripolyphosphate, was used in combination with mathematical filtering or presaturation of the extracellular resonance to separate the intra- and extracellular sodium NMR signals. Addition of 10 μM ouabain to the perfusate, perfusion with a zero potassium, low-calcium buffer, and replacement of 66% of the perfusate sodium with lithium resulted in changes in the intracellular sodium levels. An increase of 45% in the intracellular sodium was observed when changing the pacing rate from 0 to 60 beats/min (with proportional changes for intermediate pacing rates). The ratio of intracellular potassium to sodium concentration was determined to be 2.3 by NMR, indicating that a substantial amount of the intracellular potassium is undetectable with these NMR method. In addition, intracellular lithium was observed during perfusion with a lithium-containing perfusate

Evaluation of Microvascular Perfusion and Resuscitation after Severe Injury.

Science.gov (United States)

Lee, Yann-Leei L; Simmons, Jon D; Gillespie, Mark N; Alvarez, Diego F; Gonzalez, Richard P; Brevard, Sidney B; Frotan, Mohammad A; Schneider, Andrew M; Richards, William O

2015-12-01

Achieving adequate perfusion is a key goal of treatment in severe trauma; however, tissue perfusion has classically been measured by indirect means. Direct visualization of capillary flow has been applied in sepsis, but application of this technology to the trauma population has been limited. The purpose of this investigation was to compare the efficacy of standard indirect measures of perfusion to direct imaging of the sublingual microcirculatory flow during trauma resuscitation. Patients with injury severity scores >15 were serially examined using a handheld sidestream dark-field video microscope. In addition, measurements were also made from healthy volunteers. The De Backer score, a morphometric capillary density score, and total vessel density (TVD) as cumulative vessel area within the image, were calculated using Automated Vascular Analysis (AVA3.0) software. These indices were compared against clinical and laboratory parameters of organ function and systemic metabolic status as well as mortality. Twenty severely injured patients had lower TVD (X = 14.6 ± 0.22 vs 17.66 ± 0.51) and De Backer scores (X = 9.62 ± 0.16 vs 11.55 ± 0.37) compared with healthy controls. These scores best correlated with serum lactate (TVD R(2) = 0.525, De Backer R(2) = 0.576, P trauma patients, and seems to provide real-time assessment of microcirculatory perfusion. This study suggests that in severe trauma, many indirect measurements of perfusion do not correlate with microvascular perfusion. However, visualized perfusion deficiencies do reflect a shift toward anaerobic metabolism.

Heterogeneity induces spatiotemporal oscillations in reaction-diffusion systems

Science.gov (United States)

Krause, Andrew L.; Klika, Václav; Woolley, Thomas E.; Gaffney, Eamonn A.

2018-05-01

We report on an instability arising in activator-inhibitor reaction-diffusion (RD) systems with a simple spatial heterogeneity. This instability gives rise to periodic creation, translation, and destruction of spike solutions that are commonly formed due to Turing instabilities. While this behavior is oscillatory in nature, it occurs purely within the Turing space such that no region of the domain would give rise to a Hopf bifurcation for the homogeneous equilibrium. We use the shadow limit of the Gierer-Meinhardt system to show that the speed of spike movement can be predicted from well-known asymptotic theory, but that this theory is unable to explain the emergence of these spatiotemporal oscillations. Instead, we numerically explore this system and show that the oscillatory behavior is caused by the destabilization of a steady spike pattern due to the creation of a new spike arising from endogeneous activator production. We demonstrate that on the edge of this instability, the period of the oscillations goes to infinity, although it does not fit the profile of any well-known bifurcation of a limit cycle. We show that nearby stationary states are either Turing unstable or undergo saddle-node bifurcations near the onset of the oscillatory instability, suggesting that the periodic motion does not emerge from a local equilibrium. We demonstrate the robustness of this spatiotemporal oscillation by exploring small localized heterogeneity and showing that this behavior also occurs in the Schnakenberg RD model. Our results suggest that this phenomenon is ubiquitous in spatially heterogeneous RD systems, but that current tools, such as stability of spike solutions and shadow-limit asymptotics, do not elucidate understanding. This opens several avenues for further mathematical analysis and highlights difficulties in explaining how robust patterning emerges from Turing's mechanism in the presence of even small spatial heterogeneity.

Perfusion-weighted MR imaging in persistent hemiplegic migraine

Energy Technology Data Exchange (ETDEWEB)

Mourand, Isabelle; Menjot de Champfleur, Nicolas; Carra-Dalliere, Clarisse; Le Bars, Emmanuelle; Bonafe, Alain; Thouvenot, Eric [Hopital Gui de Chauliac, Service de Neuroradiologie, Montpellier (France); Roubertie, Agathe [Hopital Gui de Chauliac, Service de Neuropediatrie, Montpellier (France)

2012-03-15

Hemiplegic migraine is a rare type of migraine that has an aura characterized by the presence of motor weakness, which may occasionally last up to several days, and then resolve without sequela. Pathogenesis of migraine remains unclear and, recently, perfusion-weighted imaging (PWI) has provided a non-invasive method to study hemodynamic changes during acute attacks. Two female patients were admitted in our hospital suffering from prolonged hemiparesis. In both cases, they underwent MRI examination using a 1.5 T magnet including axial diffusion-weighted and perfusion sequences. From each perfusion MRI acquisition two regions of interest were delineated on each hemisphere and, the index of flow, cerebral blood volume, mean transit time, and time to peak were recorded and asymmetry indices from each perfusion parameter were calculated. Perfusion alterations were detected during the attacks. In one case, we observed, after 3 h of left hemiparesia, hypoperfusion of the right hemisphere. In the other case, who presented a familial hemiplegic migraine attack, on the third day of a persistent aura consisting of right hemiplegia and aphasia, PWI revealed hyperperfusion of the left hemisphere. Asymmetry indices for temporal parameters (mean transit time and time to peak) were the most sensitive. These findings resolved spontaneously after the attacks without any permanent sequel or signs of cerebral ischemia on follow-up MRI. PWI should be indicated for patients with migraine attacks accompanied by auras to assess the sequential changes in cerebral perfusion and to better understand its pathogenesis. (orig.)

Perfusion-weighted MR imaging in persistent hemiplegic migraine

International Nuclear Information System (INIS)

Mourand, Isabelle; Menjot de Champfleur, Nicolas; Carra-Dalliere, Clarisse; Le Bars, Emmanuelle; Bonafe, Alain; Thouvenot, Eric; Roubertie, Agathe

2012-01-01

Hemiplegic migraine is a rare type of migraine that has an aura characterized by the presence of motor weakness, which may occasionally last up to several days, and then resolve without sequela. Pathogenesis of migraine remains unclear and, recently, perfusion-weighted imaging (PWI) has provided a non-invasive method to study hemodynamic changes during acute attacks. Two female patients were admitted in our hospital suffering from prolonged hemiparesis. In both cases, they underwent MRI examination using a 1.5 T magnet including axial diffusion-weighted and perfusion sequences. From each perfusion MRI acquisition two regions of interest were delineated on each hemisphere and, the index of flow, cerebral blood volume, mean transit time, and time to peak were recorded and asymmetry indices from each perfusion parameter were calculated. Perfusion alterations were detected during the attacks. In one case, we observed, after 3 h of left hemiparesia, hypoperfusion of the right hemisphere. In the other case, who presented a familial hemiplegic migraine attack, on the third day of a persistent aura consisting of right hemiplegia and aphasia, PWI revealed hyperperfusion of the left hemisphere. Asymmetry indices for temporal parameters (mean transit time and time to peak) were the most sensitive. These findings resolved spontaneously after the attacks without any permanent sequel or signs of cerebral ischemia on follow-up MRI. PWI should be indicated for patients with migraine attacks accompanied by auras to assess the sequential changes in cerebral perfusion and to better understand its pathogenesis. (orig.)

Magnetic resonance cardiac perfusion imaging-a clinical perspective

International Nuclear Information System (INIS)

Hunold, Peter; Schlosser, Thomas; Barkhausen, Joerg

2006-01-01

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. (orig.)

Magnetic resonance cardiac perfusion imaging-a clinical perspective

Energy Technology Data Exchange (ETDEWEB)

Hunold, Peter; Schlosser, Thomas; Barkhausen, Joerg [University Hospital, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

2006-08-15

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. (orig.)

Modeling and design of optimal flow perfusion bioreactors for tissue engineering applications.

Science.gov (United States)

Hidalgo-Bastida, L Araida; Thirunavukkarasu, Sundaramoorthy; Griffiths, Sarah; Cartmell, Sarah H; Naire, Shailesh

2012-04-01

Perfusion bioreactors have been used in different tissue engineering applications because of their consistent distribution of nutrients and flow-induced shear stress within the tissue-engineering scaffold. A widely used configuration uses a scaffold with a circular cross-section enclosed within a cylindrical chamber and inlet and outlet pipes which are connected to the chamber on either side through which media is continuously circulated. However, fluid-flow experiments and simulations have shown that the majority of the flow perfuses through the center. This pattern creates stagnant zones in the peripheral regions as well as in those of high flow rate near the inlet and outlet. This non-uniformity of flow and shear stress, owing to a circular design, results in limited cell proliferation and differentiation in these areas. The focus of this communication is to design an optimized perfusion system using computational fluid dynamics as a mathematical tool to overcome the time-consuming trial and error experimental method. We compared the flow within a circular and a rectangular bioreactor system. Flow simulations within the rectangular bioreactor are shown to overcome the limitations in the circular design. This communication challenges the circular cross-section bioreactor configuration paradigm and provides proof of the advantages of the new design over the existing one. Copyright © 2011 Wiley Periodicals, Inc.

Acid perfusion test in gastroesophageal reflux disease

Energy Technology Data Exchange (ETDEWEB)

Kaul, B.; Petersen, H.; Grette, K.; Myrvold, H.E.

1986-01-01

An acid perfusion test, isotope scanning, endoscopy, and esophageal biopsy were performed in 101 patients with symptoms strongly suggestive of gastroesophageal reflux (GER) disease. A positive acid perfusion test within 30 min (APT) and within 5 min (TAPT) was found in 70.2% and 37.6% of the patients, respectively. A positive APT was found significantly more often in patients with than without endoscopic esophagitis, whereas a positive TAPT was found significantly more often in patients with severe symptoms than in patients with moderate symptoms, and in a significantly higher proportion of patients with than without GER by scintigraphy. Neither the APT nor the TAPT showed any dependency on the presence of histologic esophagitis. Most (97%) patients with a negative acid perfusion test, in addition to typical symptoms, also presented with scintigraphic, endoscopic, or histologic evidence of GER disease. Although it shows that the acid perfusion test, particularly when early positive, may serve as a weak predictor of the severity of GER disease, the present study gives little support to the test's clinical usefulness.

Simultaneous determination of left ventricular perfusion and function

International Nuclear Information System (INIS)

Gremillet, E.; Champailler, A.; Esquerre, J.P.; Ouhayoun, E.; Coca, F.; Furber, A.; Le Jeune, J.J.

1997-01-01

Myocardial perfusion scintigraphy is a very useful tool for the diagnosis and prognosis of coronary artery disease. The evaluation of left ventricular function during stress testing in also very useful to determine the prognosis of coronary artery disease. This chapter highlights three different imaging methods to assess left ventricular function and myocardial perfusion/ The first one consists of sequential dual isotope myocardial SPECT with ECG-gating. The second concerns magnetic resonance imaging and the third explores first pass exercise ventriculography and myocardial perfusion scintigraphy simultaneously evaluated by means of 99m Tc-sestamibi. (authors)

A Review of Liver Perfusion Method in Toxicology Studies

Directory of Open Access Journals (Sweden)

M karami

2014-06-01

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

Induction of chagasic-like arrhythmias in the isolated beating hearts of healthy rats perfused with Trypanosoma cruzi-conditioned medium

Directory of Open Access Journals (Sweden)

H. Rodriguez-Angulo

2013-01-01

Full Text Available Chagas' myocardiopathy, caused by the intracellular protozoan Trypanosoma cruzi, is characterized by microvascular alterations, heart failure and arrhythmias. Ischemia and arrythmogenesis have been attributed to proteins shed by the parasite, although this has not been fully demonstrated. The aim of the present investigation was to study the effect of substances shed by T. cruzi on ischemia/reperfusion-induced arrhythmias. We performed a triple ischemia-reperfusion (I/R protocol whereby the isolated beating rat hearts were perfused with either Vero-control or Vero T. cruzi-infected conditioned medium during the different stages of ischemia and subsequently reperfused with Tyrode's solution. ECG and heart rate were recorded during the entire experiment. We observed that triple I/R-induced bradycardia was associated with the generation of auricular-ventricular blockade during ischemia and non-sustained nodal and ventricular tachycardia during reperfusion. Interestingly, perfusion with Vero-infected medium produced a delay in the reperfusion-induced recovery of heart rate, increased the frequency of tachycardic events and induced ventricular fibrillation. These results suggest that the presence of parasite-shed substances in conditioned media enhances the arrhythmogenic effects that occur during the I/R protocol.

Tc-99m DTPA perfusion scintigraphy and color coded duplex sonography in the evaluation of minimal renal allograft perfusion

Energy Technology Data Exchange (ETDEWEB)

Bair, H.J.; Platsch, G.; Wolf, F. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Nuclear Medicine; Guenter, E.; Becker, D. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Internal Medicine 1; Rupprecht, H.; Neumayer, H.H. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Internal Medicine 4

1997-08-01

Aim: The clinical impact of perfusion scintigraphy versus color coded Duplex sonography was evaluated, with respect to their potential in assessing minimal allograft perfusion in vitally threatened kidney transplants, i.e. oligoanuric allografts suspected to have either severe rejection or thrombosis of the renal vein or artery. Methods: From July 1990 to August 1994 the grafts of 15 out of a total of 315 patients were vitally threatened. Technetium-99m DTPA scintigraphy and color coded Duplex sonography were performed in all patients. For scintigraphic evaluation of transplant perfusion analog scans up to 60 min postinjection, and time-activity curves over the first 60 sec after injection of 370-440 MBq Tc-99m diethylenetriaminepentaacetate acid (DTPA) were used and classified by a perfusion score, the time between renal and iliac artery peaks (TDiff) and the washout of the renogram curve. Additionally, evaluation of excretion function and assessment of vascular or urinary leaks were performed. By color coded Duplex sonography the perfusion in all sections of the graft as well as the vascular anastomoses were examined and the maximal blood flow velocity (Vmax) and the resistive index (RI) in the renal artery were determined by means of the pulsed Doppler device. Pathologic-anatomical diagnosis was achieved by either biopsy or post-explant histology in all grafts. Results: Scintigraphy and color coded Duplex sonography could reliably differentiate minimal (8/15) and not perfused (7/15) renal allografts. The results were confirmed either by angiography in digital subtraction technique (DSA) or the clinical follow up. Conclusion: In summary, perfusion scintigraphy and color coded Duplex sonography are comparable modalities to assess kidney graft perfusion. In clinical practice scintigraphy and colorcoded Doppler sonography can replace digital subtraction angiography in the evaluation of minimal allograft perfusion. (orig.) [Deutsch] Ziel der Studie war es, das

Post ischemic reperfusion and anoxic perfusion in the isolated heart: alteration in distribution of radionuclides and in protein synthesis

Energy Technology Data Exchange (ETDEWEB)

Schreiber, S S; Oratz, M; Rothschild, M A [Veterans Administration Hospital, New York (USA)

1980-12-01

Reperfusion after ischemia and perfusion with total anoxia were studied in the isolated guinea pig heart model, Deprivation of oxygen in both situations resulted in a marked shift of circulation from the left to the right ventricle, with markedly increased spaces of distribution of sup(99m)Tc radionuclides and albumin in the latter. In view of the complexities of measuring protein synthesis during ischemia, continuous anoxic perfusion was used to evaluate this parameter in anoxic induced arrest. There was a profound fall in protein synthesis associated with this arrest, accompanied by a fall in ATP, creatine phosphate, glycogen, potassium, and a rise in lactate production. The fall in protein synthesis was more marked in the left ventricle. The changes in synthesis were almost completely prevented by initiating cardiac arrest with high K/sup +/ (16 meq/l) at the same time as anoxia; energy metabolism remained near normal, and recovery of contractility was nearly complete. The studies demonstrated the differences in vascular distribution between the ventricles after ischemia or with perfusion anoxia, the possible difference in availability of substrate to the two ventricles under these conditions, as well as the difference in protein synthetic response, and further support the protective effect of potassium induced arrest on the hypoxic heart.

Detectable perfusion changes in MAG3 studies

International Nuclear Information System (INIS)

Shuter, B.; Bernar, A.; Roach, P.

1998-01-01

Full text: The use of 120 MBq 99m Tc-MAG 3 instead of 600 MBq 99m Tc-DTPA in renal imaging has degraded the images obtained during the perfusion phase. An increase of the minimum detectable change (MDC) in blood flow (BF) would also be expected. In transplant patients, renal BF is an important factor in patient management and the MDC should be small to allow early detection of reduced perfusion. We determined the mean and coefficient of variation (CoV: standard deviation/mean) of three renal perfusion indices as a function of counts in the time-activity curves (TACs). Transplant patients were given a dose of about 300 MBq of 99m Tc-MAG3 and images acquired at 8 fps for 60s. TACs made up from 8, 4, 2 or I images per second allowed calculation of renal perfusion indices as if doses of 300, 150, 75 and 38 MBq had been administered. Perfusion indices based on area under the TACs up to the arterial peak (API), the maximum slopes of the TACs (SPI) and the maximum slope of renal TAC and height of arterial TAC (BPI) were calculated by our routine renal software package. As the administered dose decreased, the CoV rose for all indices, least for BPI and most for API. BPI CoV increased from ∼10% at 300 MBq to 20% at 75 MBq, but API CoV rose from 6% to 46%. Mean BPI was stable over the dose range, but mean API showed a systematic increase of about 50% over the 300 MBq result. We conclude that at 120 MBq the MDC (expressed as 2*CoV) in BF is 30-60%, whereas at 600 MBq it may be as low as 10%, allowing earlier confident detection of a change in BF. The BPI was the preferred perfusion index as its mean value changed little and it had the least CoV at lower activities. The data also imply that relative kidney perfusion in the one individual will be much less accurate with 120 MBq of MAG 3

Enhanced magnetic resonance pulmonary perfusion imaging in diagnosing pulmonary embolism: preliminary investigation

International Nuclear Information System (INIS)

Huang Xiaoyong; Du Jing; Zhang Zhaoqi; Guo Xi; Yan Zixu; Jiang Hong; Wang Wei

2005-01-01

Objective: This study was designed to investigate the sensitivity and specificity of magnetic resonance pulmonary perfusion imaging (MRPP) in diagnosing pulmonary embolism (PE) compared with enhanced magnetic resonance pulmonary angiography (MRPA) and pulmonary radionuclide perfusion imaging. Methods: Fourteen patients were definitely diagnosed as PE, whose ages were from 19 to 71 years old and mean 45.5 ± 19.8 years old. All patients under went MRPA and MRPP and 3 patients were examined again after thrombolytic treatment. Five patients underwent pulmonary radionuclide perfusion imaging. Setting ROI in top, middle, bottom of lung area and abnormal area respectively, we detected signal intensity and time-signal curve to obtain the transformation rate of signal (TROS) during perfusion peak value. Results: In 14 pulmonary embolism patients, MRPA found 62 branches of pulmonary artery obstruction. Fifty-five abnormal pulmonary perfusion zones were found by MRPP, and the above results were very alike. The coincidence was 88.71%. In 14 cases, MRPP could show 25 subsegments lesion below segments. In 5 patients who had both results Of MRPP and ECT at the same time. MRPP shows 33 perfusion defect zones and 37 segments were found by ECT, the sensitivity was 89.19%. After thrombolytic treatment, both the status of the affected pulmonary artery improved markedly and perfusion defect zones reduced obviously in 3 cases by MRPP and MRPA. TROS in normal perfusion zones perfusion defect zones and low perfusion zones had significant difference (t=22.882, P<0.01). Conclusion: Contrast enhanced MR pulmonary perfusion can show both perfusion defect zones and low perfusion zones in pulmonary embolism. Time-signal curve can show the period of maximum no perfusion zones in pulmonary artery embolism zones. And the amplitude of fluctuation is small with miminum TROS. MRPP has significant values especially in showing pulmonary artery embolism in segments and subsegments. Using both MRPP and

Characterizing heterogeneous cellular responses to perturbations.

Science.gov (United States)

Slack, Michael D; Martinez, Elisabeth D; Wu, Lani F; Altschuler, Steven J

2008-12-09

Cellular populations have been widely observed to respond heterogeneously to perturbation. However, interpreting the observed heterogeneity is an extremely challenging problem because of the complexity of possible cellular phenotypes, the large dimension of potential perturbations, and the lack of methods for separating meaningful biological information from noise. Here, we develop an image-based approach to characterize cellular phenotypes based on patterns of signaling marker colocalization. Heterogeneous cellular populations are characterized as mixtures of phenotypically distinct subpopulations, and responses to perturbations are summarized succinctly as probabilistic redistributions of these mixtures. We apply our method to characterize the heterogeneous responses of cancer cells to a panel of drugs. We find that cells treated with drugs of (dis-)similar mechanism exhibit (dis-)similar patterns of heterogeneity. Despite the observed phenotypic diversity of cells observed within our data, low-complexity models of heterogeneity were sufficient to distinguish most classes of drug mechanism. Our approach offers a computational framework for assessing the complexity of cellular heterogeneity, investigating the degree to which perturbations induce redistributions of a limited, but nontrivial, repertoire of underlying states and revealing functional significance contained within distinct patterns of heterogeneous responses.

The advantage of high relaxivity contrast agents in brain perfusion

International Nuclear Information System (INIS)

Cotton, F.; Hermier, M.

2006-01-01

Accurate MRI characterization of brain lesions is critical for planning therapeutic strategy, assessing prognosis and monitoring response to therapy. Conventional MRI with gadolinium-based contrast agents is useful for the evaluation of brain lesions, but this approach primarily depicts areas of disruption of the blood-brain barrier (BBB) rather than tissue perfusion. Advanced MR imaging techniques such as dynamic contrast agent-enhanced perfusion MRI provide physiological information that complements the anatomic data available from conventional MRI. We evaluated brain perfusion imaging with gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco Imaging, Milan, Italy). The contrast-enhanced perfusion technique was performed on a Philips Intera 1.5-T MR system. The technique used to obtain perfusion images was dynamic susceptibility contrast-enhanced MRI, which is highly sensitive to T2* changes. Combined with PRESTO perfusion imaging, SENSE is applied to double the temporal resolution, thereby improving the signal intensity curve fit and, accordingly, the accuracy of the derived parametric images. MultiHance is the first gadolinium MR contrast agent with significantly higher T1 and T2 relaxivities than conventional MR contrast agents. The higher T1 relaxivity, and therefore better contrast-enhanced T1-weighted imaging, leads to significantly improved detection of BBB breakdown and hence improved brain tumor conspicuity and delineation. The higher T2 relaxivity allows high-quality T2*-weighted perfusion MRI and the derivation of good quality relative cerebral blood volume (rCBV) maps. We determined the value of MultiHance for enhanced T2*-weighted perfusion imaging of histologically proven (by surgery or stereotaxic biopsy) intraaxial brain tumors (n=80), multiple sclerosis lesions (n=10), abscesses (n=4), neurolupus (n=15) and stroke (n=16). All the procedures carried out were safe and no adverse events occurred. The acquired perfusion images were of good quality in

Integrating mean and variance heterogeneities to identify differentially expressed genes.

Science.gov (United States)

Ouyang, Weiwei; An, Qiang; Zhao, Jinying; Qin, Huaizhen

2016-12-06

In functional genomics studies, tests on mean heterogeneity have been widely employed to identify differentially expressed genes with distinct mean expression levels under different experimental conditions. Variance heterogeneity (aka, the difference between condition-specific variances) of gene expression levels is simply neglected or calibrated for as an impediment. The mean heterogeneity in the expression level of a gene reflects one aspect of its distribution alteration; and variance heterogeneity induced by condition change may reflect another aspect. Change in condition may alter both mean and some higher-order characteristics of the distributions of expression levels of susceptible genes. In this report, we put forth a conception of mean-variance differentially expressed (MVDE) genes, whose expression means and variances are sensitive to the change in experimental condition. We mathematically proved the null independence of existent mean heterogeneity tests and variance heterogeneity tests. Based on the independence, we proposed an integrative mean-variance test (IMVT) to combine gene-wise mean heterogeneity and variance heterogeneity induced by condition change. The IMVT outperformed its competitors under comprehensive simulations of normality and Laplace settings. For moderate samples, the IMVT well controlled type I error rates, and so did existent mean heterogeneity test (i.e., the Welch t test (WT), the moderated Welch t test (MWT)) and the procedure of separate tests on mean and variance heterogeneities (SMVT), but the likelihood ratio test (LRT) severely inflated type I error rates. In presence of variance heterogeneity, the IMVT appeared noticeably more powerful than all the valid mean heterogeneity tests. Application to the gene profiles of peripheral circulating B raised solid evidence of informative variance heterogeneity. After adjusting for background data structure, the IMVT replicated previous discoveries and identified novel experiment

Myocardial perfusion as an indicator of graft patency after coronary artery bypass surgery

International Nuclear Information System (INIS)

Kolibash, A.J.; Call, T.D.; Bush, C.A.; Tetalman, M.R.; Lewis, R.P.

1980-01-01

Stress and resting myocardial perfusion were assessed in 38 patients who received 96 grafts. Stress perfusion was evaluated with thallium-201 and resting myocardial blood flow distribution with radiolabeled particles. When both stress and rest perfusion were normal, graft patency was 82% (51 of 62 grafts). Graft patency was also high (81%, 13 of 16) in areas where stress perfusion abnormalities resolved or become less apparent at rest. However, when stress perfusion defects remained unchanged at rest, the graf was likely to be occuluded (73%, 11 of 15). Maintenance of normal rest perfusion or improvement of rest perfusion postoperatively was also associated with a high graft patency rate (80%, 35 of 44), whereas the development of new rest perfusion defects postoperatively implied graft occlusion

Nitric oxide permits hypoxia-induced lymphatic perfusion by controlling arterial-lymphatic conduits in zebrafish and glass catfish

DEFF Research Database (Denmark)

Dahl Ejby Jensen, Lasse; Cao, Renhai; Hedlund, Eva-Maria

2009-01-01

and lymphatic perfusion. Here we show in the adult zebrafish and glass catfish (Kryptopterus bicirrhis) that blood-lymphatic conduits directly connect arterial vessels to the lymphatic system. Under hypoxic conditions, arterial-lymphatic conduits (ALCs) became highly dilated and linearized by NO...

Spatial and seasonal heterogeneity of atmospheric particles induced reactive oxygen species in urban areas and the role of water-soluble metals

International Nuclear Information System (INIS)

Gali, Nirmal Kumar; Yang, Fenhuan; Jiang, Sabrina Yanan; Chan, Ka Lok; Sun, Li; Ho, Kin-fai; Ning, Zhi

2015-01-01

Adverse health effects are associated with exposure to atmospheric particulate matter (PM), which carry various chemical constituents and induce both exogenous and endogenous oxidative stress. This study investigated the spatial and seasonal variability of PM-induced ROS at four sites with different characteristics in Hong Kong. Cytotoxicity, exogenous and endogenous ROS was determined on a dose and time dependent analysis. Large spatial variation of ROS was observed with fine PM at urban site showing highest ROS levels while coarse PM at traffic site ranks the top. No consistent seasonal difference was observed for ROS levels among all sites. The highly heterogeneous distribution of PM-induced ROS demonstrates the differential capability of PM to produce oxidative stress, and the need to use appropriate metrics as surrogates of exposure instead of PM mass in epidemiologic studies. Several transition metals were found associated with ROS by different degree illustrating the complexity of mechanisms involved. - Highlights: • Adverse health effects are associated with size segregated atmospheric PM. • Seasonal and spatial variability of PM induced ROS determined in Hong Kong city. • Coarse PM ranks top in ROS generation on per volume and mass basis. • Traffic site demonstrated as source of potent inducer of cell toxicity. • No consistent seasonal difference observed for fine and coarse PM. - Heterogeneous PM-induced ROS distribution was observed in a city. Several water-soluble metals were associated with the ROS generation but with different degree from different sites

Pulmonary MR angiography and perfusion imaging—A review of methods and applications

Energy Technology Data Exchange (ETDEWEB)

Johns, Christopher S.; Swift, Andrew J.; Hughes, Paul J.C. [University of Sheffield (United Kingdom); Ohno, Yoshiharu [Division of Functional and Diagnostic Imaging Research, Department of Radiology, KobeUniversity Graduate School of Medicine, Kobe, Hyogo (Japan); Schiebler, Mark [UW-Madison School of Medicine and Public Health, Madison, WI (United States); Wild, Jim M., E-mail: j.m.wild@sheffield.ac.uk [University of Sheffield (United Kingdom)

2017-01-15

Highlights: • This article represents an overview of the methodology and clinical applications of pulmonary MRA and perfusion imaging. • Both contrast enhanced and non-contrast enhanced metholodology for MRA and perfusion are covered. • The current clinical uses and future directions of MRA and MR perfusion are discussed. - Abstract: The pulmonary vasculature and its role in perfusion and gas exchange is an important consideration in many conditions of the lung and heart. Currently the mainstay of imaging of the vasculature and perfusion of the lungs lies with CT and nuclear medicine perfusion scans, both of which require ionizing radiation exposure. Improvements in MRI techniques have increased the use of MRI in pulmonary vascular imaging. Here we review MRI methods for imaging the pulmonary vasculature and pulmonary perfusion, both using contrast enhanced and non-contrast enhanced methodology. In many centres pulmonary MR angiography and dynamic contrast enhanced perfusion MRI are now well established in the routine workflow of patients particularly with pulmonary hypertension and thromboembolic disease. However, these imaging modalities offer exciting new directions for future research and clinical use in other respiratory diseases where consideration of pulmonary perfusion and gas exchange can provide insight in to pathophysiology.

Brain Perfusion SPECT Imaging in Sturge - Weber Syndrome : Comparison with MR Imaging

International Nuclear Information System (INIS)

Ryu, Jin Sook; Choi, Yun Young; Moon, Dae Hyuk; Yang, Seoung Oh; Ko, Tae Sung; Yoo, Shi Joon; Lee, Hee Kyung

1996-01-01

The purpose of this study was evaluate the characteristic perfusion changes in patients with Sturge-Weber syndrome by comparison of the findings of brain MR images and perfusion SPECT images. 99m Tc-HMPAO or 99m Tc-ECD interictal brain SPECTs were performed on 5 pediatric patients with Struge-Weber syndrome within 2 weeks after MR imaging. Brain SPECTs of three patients without calcification showed diminished perfusion in the affected area on MR image. A 3 month-old patient without brain atrophy or calcification demonstrated paradoxical hyperperfusion in the affected hemisphere, and follow-up perfusion SPECT revealed decreased perfusion in the same area. The other patient with advanced calcified lesion and atrophy on MR image showed diffusely decreased perfusion in the affected hemisphere, but a focal area of increased perfusion was also noted in the ipsilateral temporal lobe on SPECT. In conclusion, brain perfusion of the affected area of Sturge-Weber syndrome patients was usually diminished, but early or advanced patients may show paradoxical diffuse or focal hyperperfusion in the affected hemisphere. Further studies are needed for better understanding of these perfusion changes and pathophysiology of Struge-Weber syndrome.

Pulmonary MR angiography and perfusion imaging—A review of methods and applications

International Nuclear Information System (INIS)

Johns, Christopher S.; Swift, Andrew J.; Hughes, Paul J.C.; Ohno, Yoshiharu; Schiebler, Mark; Wild, Jim M.

2017-01-01

Highlights: • This article represents an overview of the methodology and clinical applications of pulmonary MRA and perfusion imaging. • Both contrast enhanced and non-contrast enhanced metholodology for MRA and perfusion are covered. • The current clinical uses and future directions of MRA and MR perfusion are discussed. - Abstract: The pulmonary vasculature and its role in perfusion and gas exchange is an important consideration in many conditions of the lung and heart. Currently the mainstay of imaging of the vasculature and perfusion of the lungs lies with CT and nuclear medicine perfusion scans, both of which require ionizing radiation exposure. Improvements in MRI techniques have increased the use of MRI in pulmonary vascular imaging. Here we review MRI methods for imaging the pulmonary vasculature and pulmonary perfusion, both using contrast enhanced and non-contrast enhanced methodology. In many centres pulmonary MR angiography and dynamic contrast enhanced perfusion MRI are now well established in the routine workflow of patients particularly with pulmonary hypertension and thromboembolic disease. However, these imaging modalities offer exciting new directions for future research and clinical use in other respiratory diseases where consideration of pulmonary perfusion and gas exchange can provide insight in to pathophysiology.

Radiation response of perfused tracheal sections

International Nuclear Information System (INIS)

Ford, J.R.; Maslowski, A.J.; Braby, L.A.

2003-01-01

Full text: A model of respiratory tissue using a perfusion culture system is being developed. We are using this system to quantify the effects of normal tissue architecture and the interaction of epithelial cells with other cell types on radiation-induced bystander effects. Tracheal tissue taken from young adult male Fischer 344 rats is imbedded in a growth factor enriched agarose matrix. The chamber is designed to allow growth medium to periodically wash the epithelial surface of the tracheal lumen while maintaining the air-interface that is necessary for the normal differentiation of the epithelium. In preliminary experiments with rat trachea we have shown that a differentiated epithelial lining can be maintained for several days. Cells can be obtained for a number of different cell culture assays for endpoints such as survival and preneoplastic transformation after irradiation

Whole body perfusion for hybrid aortic arch repair: evolution of selective regional perfusion with a modified extracorporeal circuit.

Science.gov (United States)

Fernandes, Philip; Walsh, Graham; Walsh, Stephanie; O'Neil, Michael; Gelinas, Jill; Chu, Michael W A

2017-04-01

Patients undergoing hybrid aortic arch reconstruction require careful protection of vital organs. We believe that whole body perfusion with tailored dual circuitry may help to achieve optimal patient outcomes. Our circuit has evolved from a secondary circuit utilizing a cardioplegia delivery device for lower body perfusion to a dual-oxygenator circuit. This allows individually controlled regional perfusion with ease of switching from secondary to primary circuit for total body flow. The re-design allows for separate flow and temperature regulation with two oxygenators in parallel. All patients underwent a single-stage operation for simultaneous treatment of arch and descending aortic pathology via a sternotomy, using a hybrid frozen elephant trunk technique. We report six consecutive patients undergoing hybrid arch and frozen elephant trunk reconstruction using a dual-oxygenator circuit. Five patients underwent elective surgery and one was emergent. One patient had an acute dissection while three underwent concomitant procedures, including a Ross procedure and two valve-sparing root reconstructions. Three cases were redo sternotomies. The mean pump time was 358 ± 131 min, the aortic cross clamp time 243 ± 135 min, the cardioplegia volume of 33,208 ml ± 16,173, cerebral ischemia 0 min, lower body ischemia 76 ± 34 min and the average lower body perfusion time was 142 min. Two patients did not require any donor blood products. The median intensive care unit (ICU) and hospital lengths of stay (LOS) were two days and 10 days, respectively. The average peak serum lactate on CPB was 7.47 mmol/L and, at admission to the ICU, it was 3.37 mmol/L. Renal and respiratory failure developed in the salvage acute type A dissection patient. No other complications occurred in this series. Whole body perfusion as delivered through individually controlled dual-oxygenator circuitry allows maximum flexibility for hybrid aortic arch reconstruction. A modified circuit perfusion

Pulmonary perfusion ''without ventilation''

Energy Technology Data Exchange (ETDEWEB)

Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

1983-12-01

An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

Basic consideration of diffusion/perfusion imaging

International Nuclear Information System (INIS)

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

1990-01-01

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

Possibilities of differentiation of solitary focal liver lesions by computed tomography perfusion

Directory of Open Access Journals (Sweden)

Irmina Sefić Pašić

2015-08-01

Full Text Available Aim To evaluate possibilities of computed tomography (CT perfusion in differentiation of solitary focal liver lesions based on their characteristic vascularization through perfusion parameters analysis. Methods Prospective study was conducted on 50 patients in the period 2009-2012. Patients were divided in two groups: benign and malignant lesions. The following CT perfusion parameters were analyzed: blood flow (BF, blood volume (BV, mean transit time (MTT, capillary permeability surface area product (PS, hepatic arterial fraction (HAF, and impulse residual function (IRF. During the study another perfusion parameter was analyzed: hepatic perfusion index (HPI. All patients were examined on Multidetector 64-slice CT machine (GE with application of perfusion protocol for liver with i.v. administration of contrast agent. Results In both groups an increase of vascularization and arterial blood flow was noticed, but there was no significant statistical difference between any of 6 analyzed parameters. Hepatic perfusion index values were increased in all lesions in comparison with normal liver parenchyma. Conclusion Computed tomography perfusion in our study did not allow differentiation of benign and malignant liver lesions based on analysis of functional perfusion parameters. Hepatic perfusion index should be investigated in further studies as a parameter for detection of possible presence of micro-metastases in visually homogeneous liver in cases with no lesions found during standard CT protocol

[Acute stent thrombosis and reverse transient left ventricular dilatation after performing a single-photon emission computed tomography myocardial perfusion].

Science.gov (United States)

Miranda, B; Pizzi, M N; Aguadé-Bruix, S; Domingo, E; Candell-Riera, J

2015-01-01

A 63-year-old male patient with a history of stent implantation in the left anterior descending three months before. Due to the presentation of vegetative symptoms, he was referred for gated-SPECT myocardial perfusion. During acquisition of the resting images he presented chest pain and ST segment elevation, so that urgent cardiac catheterization was performed, showing stent thrombosis. Rest perfusion imaging showed a defect in anterior and apical perfusion, more severe and extensive than in the stress images, with striking left ventricular dilatation and a fall in the ejection fraction related to the acute ischemia phenomenon. Intense exercise is associated with a transient activation of the coagulation system and hemodynamic changes that might induce thrombosis, especially in recently implanted coronary stents that probably still have not become completely endothelialized. Copyright © 2014 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Diagnostic value of exercise induced 18F-FDG myocardial metabolism scintigraphy in myocardial ischemia

International Nuclear Information System (INIS)

Shen Rui; He Zuoxiang; Shi Rongfang; Liu Xiujie; Tian Yueqin; Guo Feng; Wei Hongxing; Wu Yongjian; Qin Xuewen; Gao Runlin

2006-01-01

Objective: To evaluate the feasibility and diagnostic accuracy of exercise induced myocardial imaging with 18 F-fluorodeoxyglucose (FDG) in myocardial ischemia. Methods: Twenty-six patients with known or suspected coronary artery, disease (CAD) and with no prior myocardial infarction underwent simultaneous myocardial perfusion and metabolism imaging following intravenous injection of 99 Tc m -methoxy-isobutylisonitrile ( 99 Tc m -sestamibi) and 18 F-FDG at peak exercise. Subsequently rest perfusion imaging and coronary angiography (CAG) were performed in all patients. Exercise 18 F-FDG myocardial imaging was compared with 99 Tc m -sestamibi imaging and CAG. Results: In 22 patients with ≥50% narrowing over l coronary artery, 18 had perfusion abnormalities (sensitivity 82%), whereas 20 had abnormal myocardial 18 F-FDG uptake (sensitivity 91%, P>0.05). Patients with reversible (12 cases) or partial reversible (3 cases) perfusion abnormalities had increased myocardial 18 F-FDG uptake in abnormal perfusion segments. Compared with CAG, perfusion defect was seen in myocardial segments corresponding to 25 vascular territories of 51 vessels with ≥50% narrowing in 22 patients in 99 Tc m -sestamibi imaging (sensitivity 49%), whereas increased 18 F-FDG uptake was seen in 34 vascular territories (sensitivity 67%, P=0.008). Conclusions: Exercise induced myocardial ischemia can be imaged directly with 18 F-FDG. Combined exercise 18 F-FDG and 99 Tc m -sestamibi imaging provides a better assessment of exercise-induced myocardial ischemia as compared with exercise-rest perfusion imaging. (authors)

Perfusion scintigraphy of the hand with sup(99m)Tc labelled microspheres - an alternative to angiography in the diagnosis of peripheral perfusion disturbances

Energy Technology Data Exchange (ETDEWEB)

Karnahl, H M; Hedde, J P [Allgemeine Ortskrankenkasse Koeln (Germany, F.R.). Strahleninstitut

1979-12-01

sup(99m)Tc labelled microspheres were injected in the A. brachialis in addition to angiography of the hand in 15 patients. The hereby obtained results show good correlation between angiography and scintigraphy. The completely normal perfusion scintigram of the hand allows to dispense with angiography. The pathological scan, however, requires angiography. Perfusion scintigraphy of the hand seems to be most useful in the follow-up of therapeutic effects in perfusion disturbances.

Effects of perfusion detect on the measurement of left ventricular mass, ventricular volume and post-stress left ventricular ejection fraction in gated myocardial perfusion SPECT

International Nuclear Information System (INIS)

Ahn, Byeong Cheol; Bae, Sun Keun; Lee, Sang Woo; Jeong, Sin Young; Lee, Jae Tae; Lee, Kyu Bo

2002-01-01

The presence of perfusion defect may influence the left ventricular mass (LVM) measurement by quantitative gated myocardial perfusion SPECT (QGS), and ischemic myocardium, usually showing perfusion defect may produce post-stress LV dysfunction. This study was aimed to evaluated the effects of extent and reversibility of perfusion defect on the automatic measurement of LVM by QGS and to investigate the effect of reversibility of perfusion defect on post-stress LV dysfunction. Forty-six patients (male/female=34:12, mean age=64 years) with perfusion defect on myocardial perfusion SPECT underwent rest and post-stress QGS. Forty patients (87%) showed reversible defect. End-diastolic volume (EDV), end-systolic volume (ESV), LV ejection fraction (EF), and LV myocardial volume were obtained from QGS by autoquant program, and LVM was calculated by multiplying the LV myocardial volume by the specific gravity of myocardium. LVMs measured at rest and post-stress QGS showed good correlation, and higher correlation was founded in the subjects with fixed perfusion defect and with small defect (smaller than 20%). There were no significant differences in EDVs, ESVs and EFs between obtained by rest and post-stress QGS in patients with fixed myocardial defect. Whereas, EF obtained by post-stress QGS was lower than that by rest QGS in patients with reversible defect and 10 (25%) of them showed decreases in EF more than 5% in post-stress QGS, as compared to that of rest QGS. Excellent correlations of EDVs, ESVs, EFs between rest and post-stress QGS were noted. Patients with fixed defect had higher correlation between defect can affect LVM measurement by QGS and patients with reversible defect shows post-stress LV dysfunction more frequently than patients with fixed perfusion defect

Visualization of myocardial perfusion derived from coronary anatomy

NARCIS (Netherlands)

Termeer, M.A.; Bescos, J.O.; Breeuwer, M.; Vilanova, A.; Gerritsen, F.A.; Gröller, M.E.; Nagel, Eike

2008-01-01

Visually assessing the effect of the coronary artery anatomy on the perfusion of the heart muscle in patients with coronary artery disease remains a challenging task. We explore the feasibility of visualizing this effect on perfusion using a numerical approach. We perform a computational simulation

Combining Diffusion Tensor Metrics and DSC Perfusion Imaging: Can It Improve the Diagnostic Accuracy in Differentiating Tumefactive Demyelination from High-Grade Glioma?

Science.gov (United States)

Hiremath, S B; Muraleedharan, A; Kumar, S; Nagesh, C; Kesavadas, C; Abraham, M; Kapilamoorthy, T R; Thomas, B

2017-04-01

Tumefactive demyelinating lesions with atypical features can mimic high-grade gliomas on conventional imaging sequences. The aim of this study was to assess the role of conventional imaging, DTI metrics ( p:q tensor decomposition), and DSC perfusion in differentiating tumefactive demyelinating lesions and high-grade gliomas. Fourteen patients with tumefactive demyelinating lesions and 21 patients with high-grade gliomas underwent brain MR imaging with conventional, DTI, and DSC perfusion imaging. Imaging sequences were assessed for differentiation of the lesions. DTI metrics in the enhancing areas and perilesional hyperintensity were obtained by ROI analysis, and the relative CBV values in enhancing areas were calculated on DSC perfusion imaging. Conventional imaging sequences had a sensitivity of 80.9% and specificity of 57.1% in differentiating high-grade gliomas ( P = .049) from tumefactive demyelinating lesions. DTI metrics ( p : q tensor decomposition) and DSC perfusion demonstrated a statistically significant difference in the mean values of ADC, the isotropic component of the diffusion tensor, the anisotropic component of the diffusion tensor, the total magnitude of the diffusion tensor, and rCBV among enhancing portions in tumefactive demyelinating lesions and high-grade gliomas ( P ≤ .02), with the highest specificity for ADC, the anisotropic component of the diffusion tensor, and relative CBV (92.9%). Mean fractional anisotropy values showed no significant statistical difference between tumefactive demyelinating lesions and high-grade gliomas. The combination of DTI and DSC parameters improved the diagnostic accuracy (area under the curve = 0.901). Addition of a heterogeneous enhancement pattern to DTI and DSC parameters improved it further (area under the curve = 0.966). The sensitivity increased from 71.4% to 85.7% after the addition of the enhancement pattern. DTI and DSC perfusion add profoundly to conventional imaging in differentiating tumefactive

Dynamic perfusion patterns in temporal lobe epilepsy

International Nuclear Information System (INIS)

Dupont, Patrick; Paesschen, Wim van; Zaknun, John J.; Maes, Alex; Tepmongkol, Supatporn; Locharernkul, Chaichon; Vasquez, Silvia; Carpintiero, Silvina; Bal, C.S.; Dondi, Maurizio

2009-01-01

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

Dynamic perfusion patterns in temporal lobe epilepsy

Energy Technology Data Exchange (ETDEWEB)

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

2009-05-15

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

Phase correction of MR perfusion/diffusion images

International Nuclear Information System (INIS)

Chenevert, T.L.; Pipe, J.G.; Brunberg, J.A.; Yeung, H.N.

1989-01-01

Apparent diffusion coefficient (ADC) and perfusion MR sequences are exceptionally sensitive to minute motion and, therefore, are prone to bulk motions that hamper ADC/perfusion quantification. The authors have developed a phase correction algorithm to substantially reduce this error. The algorithm uses a diffusion-insensitive data set to correct data that are diffusion sensitive but phase corrupt. An assumption of the algorithm is that bulk motion phase shifts are uniform in one dimension, although they may be arbitrarily large and variable from acquisition to acquisition. This is facilitated by orthogonal section selection. The correction is applied after one Fourier transform of a two-dimensional Fourier transform reconstruction. Imaging experiments on rat and human brain demonstrate significant artifact reduction in ADC and perfusion measurements

Ventilation perfusion radionuclide imaging in cryptogenic fibrosing alveolitis

International Nuclear Information System (INIS)

Bourke, S.J.; Hawkins, T.; Keavey, P.M.; Gascoigne, A.D.; Corris, P.A.

1993-01-01

There is increasing interest in ventilation perfusion (V/Q) imaging in cryptogenic fibrosing alveolitis because of the data these scans provide on the dynamic V/Q relationships in such patients undergoing single lung transplantation. We analysed the V/Q scans of 45 consecutive patients with advanced cryptogenic fibrosing alveolitis being considered for single lung transplantation. Scans were classified according to the presence, severity and degree of matching of defects in ventilation and perfusion images and the results were compared with the data obtained from lung function tests. Ventilation images showed defects in 13 (29%) and ''washout delay'' in 15 (33%) patients; 10 (22%) patients had asymmetric distribution of ventilation with one lung receiving >60% of total ventilation. Perfusion images showed normal perfusion in 8 (18%), mild defects in 18 (40%) and major defects in 19 (42%) patients. The distribution of perfusion between lungs was significantly asymmetric in 20 (45%) patients. V/Q images were matched in 15 (33%), mildly mismatched in 15 (33%) and severely mismatched in 15 (33%) patients, but the degree of V/Q mismatch did not show a relationship to KCO, PaO 2 or A-aO 2 gradient. The appearances were atypical of pulmonary embolism in eight patients. (Author)

Feasibility of high-resolution quantitative perfusion analysis in patients with heart failure.

Science.gov (United States)

Sammut, Eva; Zarinabad, Niloufar; Wesolowski, Roman; Morton, Geraint; Chen, Zhong; Sohal, Manav; Carr-White, Gerry; Razavi, Reza; Chiribiri, Amedeo

2015-02-12

Cardiac magnetic resonance (CMR) is playing an expanding role in the assessment of patients with heart failure (HF). The assessment of myocardial perfusion status in HF can be challenging due to left ventricular (LV) remodelling and wall thinning, coexistent scar and respiratory artefacts. The aim of this study was to assess the feasibility of quantitative CMR myocardial perfusion analysis in patients with HF. A group of 58 patients with heart failure (HF; left ventricular ejection fraction, LVEF ≤ 50%) and 33 patients with normal LVEF (LVEF >50%), referred for suspected coronary artery disease, were studied. All subjects underwent quantitative first-pass stress perfusion imaging using adenosine according to standard acquisition protocols. The feasibility of quantitative perfusion analysis was then assessed using high-resolution, 3 T kt perfusion and voxel-wise Fermi deconvolution. 30/58 (52%) subjects in the HF group had underlying ischaemic aetiology. Perfusion abnormalities were seen amongst patients with ischaemic HF and patients with normal LV function. No regional perfusion defect was observed in the non-ischaemic HF group. Good agreement was found between visual and quantitative analysis across all groups. Absolute stress perfusion rate, myocardial perfusion reserve (MPR) and endocardial-epicardial MPR ratio identified areas with abnormal perfusion in the ischaemic HF group (p = 0.02; p = 0.04; p = 0.02, respectively). In the Normal LV group, MPR and endocardial-epicardial MPR ratio were able to distinguish between normal and abnormal segments (p = 0.04; p = 0.02 respectively). No significant differences of absolute stress perfusion rate or MPR were observed comparing visually normal segments amongst groups. Our results demonstrate the feasibility of high-resolution voxel-wise perfusion assessment in patients with HF.

Perfusion lung scanning: differentiation of primary from thromboembolic pulmonary hypertension

International Nuclear Information System (INIS)

Lisbona, R.; Kreisman, H.; Novales-Diaz, J.; Derbekyan, V.

1985-01-01

Of eight patients with pulmonary arterial hypertension, final diagnosis established by autopsy or angiography, four had primary hypertension and four hypertension from thromboembolism. The perfusion lung scan was distinctly different in the two groups. The lung scan in primary pulmonary hypertension was associated with nonsegmental, patchy defects of perfusion, while in thromboembolic hypertensives it was characterized by segmental and/or lobar defects of perfusion with or without subsegmental defects. The perfusion lung scan is a valuable, noninvasive study in the evaluation of the patient with pulmonary hypertension of undetermined cause and in the exclusion of occult large-vessel pulmonary thromboembolism

Reducing the effects of acoustic heterogeneity with an iterative reconstruction method from experimental data in microwave induced thermoacoustic tomography

International Nuclear Information System (INIS)

Wang, Jinguo; Zhao, Zhiqin; Song, Jian; Chen, Guoping; Nie, Zaiping; Liu, Qing-Huo

2015-01-01

Purpose: An iterative reconstruction method has been previously reported by the authors of this paper. However, the iterative reconstruction method was demonstrated by solely using the numerical simulations. It is essential to apply the iterative reconstruction method to practice conditions. The objective of this work is to validate the capability of the iterative reconstruction method for reducing the effects of acoustic heterogeneity with the experimental data in microwave induced thermoacoustic tomography. Methods: Most existing reconstruction methods need to combine the ultrasonic measurement technology to quantitatively measure the velocity distribution of heterogeneity, which increases the system complexity. Different to existing reconstruction methods, the iterative reconstruction method combines time reversal mirror technique, fast marching method, and simultaneous algebraic reconstruction technique to iteratively estimate the velocity distribution of heterogeneous tissue by solely using the measured data. Then, the estimated velocity distribution is used subsequently to reconstruct the highly accurate image of microwave absorption distribution. Experiments that a target placed in an acoustic heterogeneous environment are performed to validate the iterative reconstruction method. Results: By using the estimated velocity distribution, the target in an acoustic heterogeneous environment can be reconstructed with better shape and higher image contrast than targets that are reconstructed with a homogeneous velocity distribution. Conclusions: The distortions caused by the acoustic heterogeneity can be efficiently corrected by utilizing the velocity distribution estimated by the iterative reconstruction method. The advantage of the iterative reconstruction method over the existing correction methods is that it is successful in improving the quality of the image of microwave absorption distribution without increasing the system complexity

Simultaneous Multiagent Hyperpolarized ¹³C Perfusion Imaging

DEFF Research Database (Denmark)

von Morze, Cornelius; Bok, Robert A.; Reed, Galen D.

2014-01-01

in simulations. "Tripolarized" perfusion MRI methods were applied to initial preclinical studies with differential conditions of vascular permeability, in normal mouse tissues and advanced transgenic mouse prostate tumors. Results: Dynamic imaging revealed clear differences among the individual tracer...... distributions. Computed permeability maps demonstrated differential permeability of brain tissue among the tracers, and tumor perfusion and permeability were both elevated over values expected for normal tissues. Conclusion: Tripolarized perfusion MRI provides new molecular imaging measures for specifically...

Dynamic Chest Image Analysis: Model-Based Perfusion Analysis in Dynamic Pulmonary Imaging

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Kiuru Aaro

2003-01-01

Full Text Available The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion analysis. According to perfusion properties, we first devise a novel mathematical function to form a perfusion model. A simple yet accurate approach is further introduced to extract cardiac systolic and diastolic phases from the heart, so that this cardiac information may be utilized to accelerate the perfusion analysis and improve its sensitivity in detecting pulmonary perfusion abnormalities. This makes perfusion analysis not only fast but also robust in computation; consequently, perfusion analysis becomes computationally feasible without using contrast media. Our clinical case studies with 52 patients show that this technique is effective for pulmonary embolism even without using contrast media, demonstrating consistent correlations with computed tomography (CT and nuclear medicine (NM studies. This fluoroscopical examination takes only about 2 seconds for perfusion study with only low radiation dose to patient, involving no preparation, no radioactive isotopes, and no contrast media.

Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents

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Mirco Galiè

2005-05-01

Full Text Available Contrast-enhanced ultrasound (CEUS is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 μm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI. Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes.

A novel combination technique of cold crystalloid perfusion but not cold storage facilitates transplantation of canine hearts donated after circulatory death.

Science.gov (United States)

Rosenfeldt, Franklin; Ou, Ruchong; Salamonsen, Robert; Marasco, Silvana; Zimmet, Adam; Byrne, Joshua; Cosic, Filip; Saxena, Pankaj; Esmore, Donald

2016-11-01

Donation after circulatory death (DCD) represents a potential new source of hearts to increase the donor pool. We showed previously that DCD hearts in Greyhound dogs could be resuscitated and preserved by continuous cold crystalloid perfusion but not by cold static storage and could demonstrate excellent contractile and metabolic function on an in vitro system. In the current study, we demonstrate that resuscitated DCD hearts are transplantable. Donor Greyhound dogs (n = 12) were divided into perfusion (n = 8) and cold static storage (n = 4) groups. General anesthesia was induced and ventilation ceased for 30 minutes to achieve circulatory death. Donor cardiectomy was performed, and for 4 hours the heart was preserved by controlled reperfusion, followed by continuous cold perfusion with an oxygenated crystalloid perfusate or by static cold storage, after which orthotopic heart transplantation was performed. Recovery was assessed over 4 hours by hemodynamic monitoring. During cold perfusion, hearts showed continuous oxygen consumption and low lactate levels, indicating aerobic metabolism. The 8 dogs in the perfusion group were weaned off bypass, and 4 hours after bypass produced cardiac output of 4.73 ± 0.51 liters/min, left ventricular power of 7.63 ± 1.32 J/s, right ventricular power of 1.40 ± 0.43 J/s, and left ventricular fractional area shortening of 39.1% ± 5.2%, all comparable to pre-transplant values. In the cold storage group, 3 of 4 animals could not be weaned from cardiopulmonary bypass, and the fourth exhibited low-level function. Cold crystalloid perfusion, but not cold static storage, can resuscitate and preserve the DCD donor heart in a canine model of heart transplantation, thus rendering it transplantable. Controlled reperfusion and cold crystalloid perfusion have potential for clinical application in DCD transplantation. Copyright © 2016. Published by Elsevier Inc.

Diabetes patients show different time-course of myocardial perfusion improvement after coronary artery bypass grafting

International Nuclear Information System (INIS)

Lee, J. J.; Seok, J. W.; Eo, J. S.

2005-01-01

Diabetes mellitus is an independent risk factor of cardiovascular disease. Diabetes is known to cause microangiopathy. The microangiopathy is hardly detectable on the coronary angiography. Myocardial perfusion imaging shows the resultant perfusion status which reflects the microangiopathy. For patients who underwent revascularization, the microangiopathy could affect the myocardial perfusion improvement. Diabetes patients probably experience the different myocardial perfusion improvement as compared to the non-diabetes patients although they have similar angiographic findings. The aim of this study is to find out whether there is a time-course difference of perfusion improvement between the diabetes and non diabetes patients who showed patent angiographic findings after coronary artery grafting surgery (CABG). A total of 129 patients who underwent coronary artery bypass grafting surgery were enrolled in this study. Myocardial SPECTs performed at previous, short-term (3 month), and mid-term (1 year) to CABG. One-year follow up angiography was done 411±121 days after surgery. Graft patency was determined according to the FitzGibbon et al. Segments were assigned to vascular territories using a 20 segment model. The segments of excellent patency were included in this study. Time course differences of concerned segments were analyzed using RMANOVA. The number of segments enrolled was 764 of diabetes and 1083 of non-diabetes. At short-term follow up, reversibility score was 2.8±8.1% in diabetes and 0.3±7.5% in non-diabetes. At long-term follow up, reversibility score was 1.8±8.0% in diabetes and 0.1±7.3% in non-diabetes. The time-course of reversibility score was significantly different between the diabetes and non diabetes (p<0.001) Diabetic segments showed high residual reversibility score than non-diabetic segments after CABG although the angiographic finding was patent in both groups. This result is maybe attributable to microangiopathy induced by diabetes

Myocardial perfusion SPECT imaging in patients with myocardial bridging

International Nuclear Information System (INIS)

Fang Wei; Qiu Hong; Yang Weixian; Wang Feng; He Zuoxiang

2008-01-01

Objective: Stress myocardial perfusion SPECT imaging was used to assess myocardial ischemia in patients with myocardial bridging. Methods: Ninety-six patients with myocardial bridging of the left anterior descending artery documented by coronary angiography were included in this study. All under- went exercise or pharmacological stress myocardial perfusion SPECT assessing myocardial ischemia. None had prior myocardial infarction. One year follow-up by telephone interview was performed in all patients. Results The mean stenotic severity of systolic phase on angiography was (65 ± 19)%. In the SPECT study, 20 of 96 (20.8%) patients showed abnormal perfusion. This percentage was significantly higher than that of stress electrocardiogram (ECG). The higher positive rate of SPECT perfusion images was showed in the group of patients with severe systolic narrowing (≥75%) than that with mild-to-moderate systolic narrowing (50% vs 6.3%, P<0.001). The prevalence of abnormal image was significantly higher in ELDERLY PEOPLE; patients with STT change on rest ECG than in those with normal rest ECG (54.2% vs 9.7%, P<0.001). During follow-up, one patient with abnormal SPECT perfusion image sustained angina and accepted percutaneous coronary intervention, and no cardiac event occurred in patients with normal images. Conclusions: Stress myocardial perfusion SPECT imaging can be used effectively for assessing myocardial ischemia and has potential prognostic value for patients with myocardial bridging. (authors)

Thallium-201 myocardial perfusion imaging during adenosine-induced coronary vasodilation in patients with ischemic heart disease

International Nuclear Information System (INIS)

Takeishi, Yasuchika; Chiba, Junya; Abe, Shinya

1992-01-01

Thallium-201 ( 201 Tl) myocardial perfusion imaging during adenosine infusion was performed in consecutive 55 patients with suspected coronary artery disease. Adenosine was infused intravenously at a rate of 0.14 mg/kg/min for 6 minutes and a dose of 111 MBq of 201 Tl was administered in a separate vein at the end of third minutes of infusion. Myocardial SPECT imaging was begun 5 minutes and 3 hours after the end of adenosine infusion. For evaluating the presence of perfusion defects, 2 short axis images at the basal and spical levels and a vertical long axis image at the mid left ventricle were used. The regions with decreased 201 Tl uptake were assessed semi-quantitatively. Adenosine infusion caused a slight reduction in systolic blood pressure and an increase in heart rate. The rate pressure products increased slightly (9314±2377 vs. 10360±2148, p 201 Tl myocardial imaging during adenosine infusion was considered to be safe and useful for evaluating the patients with ischemic heart disease. (author)

Heterogeneous policies, heterogeneous technologies: The case of renewable energy

International Nuclear Information System (INIS)

Nicolli, Francesco; Vona, Francesco

2016-01-01

This paper investigates empirically the effect of market regulation and renewable energy policies on innovation activity in different renewable energy technologies. For the EU countries and the years 1980 to 2007, we built a unique dataset containing information on patent production in eight different technologies, proxies of market regulation and technology-specific renewable energy policies. Our main finding is that, compared to privatisation and unbundling, reducing entry barriers is a more significant driver of renewable energy innovation, but that its effect varies across technologies and is stronger in technologies characterised by potential entry of small, independent power producers. In addition, the inducement effect of renewable energy policies is heterogeneous and more pronounced for wind, which is the only technology that is mature and has high technological potential. Finally, ratification of the Kyoto protocol, which determined a more stable and less uncertain policy framework, amplifies the inducement effect of both energy policy and market liberalisation. - Highlights: • We study the effect of market regulation and energy policy on renewable technologies. • Reducing entry barriers is a significant driver of renewable energy innovation. • The Kyoto protocol amplifies the effect of both energy policy and liberalisation. • These effects are heterogeneous across technologies and stronger for wind.

Effects of ethanol and hyperosmotic perfusates on albumin synthesis and release

International Nuclear Information System (INIS)

Rothschild, M.A.; Oratz, M.; Schreiber, S.S.; Mongelli, J.

1986-01-01

Sucrose and ethanol inhibit albumin synthesis; sucrose via an osmotic mechanism and ethanol during its metabolism. The present study was undertaken to compare the effects of both of these agents on albumin synthesis and secretion, and to see if ethanol inhibition could be related to an osmotic effect. Male, fed rabbits served as liver donors in all studies. There were a total of 35 studies: 13 control; 10 ethanol (39 to 52 mM); 4 cycloheximide (0.5 mM), and 8 sucrose (1%). Plasma volume was measured with 125 I-albumin (human) and extracellular volume measured with either /sup 99m/Tc diethylenetriamine pentaacetic acid or [ 14 C]sucrose. During perfusion, rabbit albumin content in the perfusate was measured immunologically every 15 to 30 min for 225 min. Interstitial albumin efflux was measured by the rate of appearance in the perfusate of 125 I-albumin given to 10 other rabbits 3 days prior to hepatic removal and perfusion. During the initial 75 min of perfusion, 74% of the in vivo equilibrated exchangeable 125 I-albumin appeared in the perfusate, and during this period the rabbit albumin that entered the perfusate was taken to represent efflux from the interstitial volume plus synthesis. Rabbit albumin appearing in the perfusate during the later period of 150 min was taken to represent mainly synthesis and was used to calculate the amount of albumin that would be synthesized in 75 min. The difference between these two values would be hepatic interstitial albumin appearing in the perfusate

Prognostic Value of Quantitative Stress Perfusion Cardiac Magnetic Resonance.

Science.gov (United States)

Sammut, Eva C; Villa, Adriana D M; Di Giovine, Gabriella; Dancy, Luke; Bosio, Filippo; Gibbs, Thomas; Jeyabraba, Swarna; Schwenke, Susanne; Williams, Steven E; Marber, Michael; Alfakih, Khaled; Ismail, Tevfik F; Razavi, Reza; Chiribiri, Amedeo

2018-05-01

This study sought to evaluate the prognostic usefulness of visual and quantitative perfusion cardiac magnetic resonance (CMR) ischemic burden in an unselected group of patients and to assess the validity of consensus-based ischemic burden thresholds extrapolated from nuclear studies. There are limited data on the prognostic value of assessing myocardial ischemic burden by CMR, and there are none using quantitative perfusion analysis. Patients with suspected coronary artery disease referred for adenosine-stress perfusion CMR were included (n = 395; 70% male; age 58 ± 13 years). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, aborted sudden death, and revascularization after 90 days. Perfusion scans were assessed visually and with quantitative analysis. Cross-validated Cox regression analysis and net reclassification improvement were used to assess the incremental prognostic value of visual or quantitative perfusion analysis over a baseline clinical model, initially as continuous covariates, then using accepted thresholds of ≥2 segments or ≥10% myocardium. After a median 460 days (interquartile range: 190 to 869 days) follow-up, 52 patients reached the primary endpoint. At 2 years, the addition of ischemic burden was found to increase prognostic value over a baseline model of age, sex, and late gadolinium enhancement (baseline model area under the curve [AUC]: 0.75; visual AUC: 0.84; quantitative AUC: 0.85). Dichotomized quantitative ischemic burden performed better than visual assessment (net reclassification improvement 0.043 vs. 0.003 against baseline model). This study was the first to address the prognostic benefit of quantitative analysis of perfusion CMR and to support the use of consensus-based ischemic burden thresholds by perfusion CMR for prognostic evaluation of patients with suspected coronary artery disease. Quantitative analysis provided incremental prognostic value to visual assessment and

Reactivity of the isolated perfused rat tail vascular bed

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A.S. França

1997-07-01

Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

Improved exercise myocardial perfusion during lidoflazine therapy

International Nuclear Information System (INIS)

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

1983-01-01

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

Visceral Perfusion Scintigraphy with {sup 131}I-Labelled Albumin Macroaggregates

Energy Technology Data Exchange (ETDEWEB)

Ueda, H.; Yamada, H.; Kitani, K.; Nagatani, M.; Takeda, T.; Migita, T.; Iio, M; Kameda, H. [University of Tokyo, Tokyo (Japan)

1969-05-15

The blood supply through the hepatic artery, superior mesenteric artery and portal vein to the visceral organs was studied in 60 cases of various hepatic disorders by scintigraphy after the selective introduction of {sup 131}I MAA by means of visceral arterial catheterization or percutaneous splenic puncture. A comparison of the radioactivities of the liver and the spleen after celiac arterial infusion (celiac perfusion scanning) indicated how much blood in the celiac artery was distributed to the two major arterial branches - the hepatic and splenic. Dominant perfusion was found through the hepatic branch in liver cirrhosis, whereas significantly dominant splenic blood perfusion was found in idiopathic non-cirrhotic portal hypertension. This remarkable contrast of the mode of celiac perfusion in two disorders indicated the etiological difference of these diseases. In malignant neoplasm of the liver, the dominant or exclusive celiac arterial perfusion was found in the tumour region. In these cases, liver scanning by the splenic injection of MAA (portal perfusion scanning) delineated the tumour region as a negative defect similar to the conventional {sup 198}Au colloid scanning. Consequently, from these two perfusion scintigrams the 'key and key-hole' pattern was demonstrated. It was concluded that a neoplastic lesion, primary or metastatic, has the predominant blood supply through the hepatic artery rather than through the portal vein. Celiac perfusion scanning of liver cystosis revealed multiple negative defects. This information was useful for differentiating a malignant tumour, which is usually impossible by conventional liver scanning. Celiac perfusion scanning was also useful for the diagnosis of arterial venous communication. In one case of liver .cancer with cirrhosis and another case with stomach varices, the arterial-v.enous communication was indicated by the appearance of the lung contour in the celiac perfusion scan. In both cases, the combined presence

Heterogeneity in preferences and behavior in threshold models

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Philip R Neary

2017-12-01

Full Text Available A coordination game is repeatedly played on a graph by players (vertices who have heterogeneous cardinal preferences and whose strategy choice is governed by the individualistic asynchronous logit dynamic. The idea of potential driven autonomy of sets of players is used to derive results on the possibility of heterogeneous preferences leading to heterogeneous behavior. In particular, a class of graphs is identified such that for large enough graphs in this class, diversity in ordinal preferences will nearly always lead to heterogeneity in behavior, regardless of the cardinal strength of the preferences. These results have implications for network design problems, such as when a social planner wishes to induce homogeneous/heterogeneous behavior in a population.

Large cerebral perfusion defects observed in brain perfusion SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients

Energy Technology Data Exchange (ETDEWEB)

So, Young; Kim, Hahn Young; Roh, Hong Gee; Han, Seol Heui [Konkuk University School of Medicine, Seoul (Korea, Republic of)

2007-07-01

Transient global amnesia (TGA) is a memory disorder characterized by an episode of antegrade amnesia and bewilderment which persists for several hours. We analyzed brain perfusion SPECT findings and clinical outcome of patients who suffered from TGA. From September 2005 to August 2007, 12 patients underwent Tc-99m ECD brain perfusion SPECT for neuroimaging of TGA. All patients also underwent MRI and MRA including DWI (MRI). Among them, 10 patients who could be chased more than 6 months were included in this study. Their average age was 60.74.0 yrs (M: F = 2: 8) and the average duration of amnesia was 4.42.2 hrs (1 hr {approx} 7 hrs). Duration from episode of amnesia to SPECT was 4.32.4 days (1{approx}9 days). Precipitating factors could be identified in 6 patients: emotional stress 3, hair dyeing 1, taking a nap 1 and angioplasty 1. SPECT and MRI was visually assessed, No cerebral perfusion defect was observed on SPECT in 3 patients and their clinical outcome was all good. Among 7 patients who had cerebral perfusion defects on SPECT, 3 patients had good clinical outcome, while others did not: one had hypercholesterolemia, another had depression, and 2 patients with cerebral perfusion defects at both temporoparetal cortex was later diagnosed as early Alzheimer's disease (AD) and mild cognitive impairment (MCI). MRI was negative in 6 patients and 3 of them had excellent clinical outcome while other 3 were diagnosed as hypercholesterolemia, early AD and MCI. Among 4 patients with positive MRI, 3 showed good clinical outcome and their MRI showed lesions at medial temporal cortex and/or vertebral artery. One patient with microcalcification at left putamen was diagnosed to have depression. Large cerebral perfusion defects on SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients which usually shows negative MRI.

Large cerebral perfusion defects observed in brain perfusion SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients

International Nuclear Information System (INIS)

So, Young; Kim, Hahn Young; Roh, Hong Gee; Han, Seol Heui

2007-01-01

Transient global amnesia (TGA) is a memory disorder characterized by an episode of antegrade amnesia and bewilderment which persists for several hours. We analyzed brain perfusion SPECT findings and clinical outcome of patients who suffered from TGA. From September 2005 to August 2007, 12 patients underwent Tc-99m ECD brain perfusion SPECT for neuroimaging of TGA. All patients also underwent MRI and MRA including DWI (MRI). Among them, 10 patients who could be chased more than 6 months were included in this study. Their average age was 60.74.0 yrs (M: F = 2: 8) and the average duration of amnesia was 4.42.2 hrs (1 hr ∼ 7 hrs). Duration from episode of amnesia to SPECT was 4.32.4 days (1∼9 days). Precipitating factors could be identified in 6 patients: emotional stress 3, hair dyeing 1, taking a nap 1 and angioplasty 1. SPECT and MRI was visually assessed, No cerebral perfusion defect was observed on SPECT in 3 patients and their clinical outcome was all good. Among 7 patients who had cerebral perfusion defects on SPECT, 3 patients had good clinical outcome, while others did not: one had hypercholesterolemia, another had depression, and 2 patients with cerebral perfusion defects at both temporoparetal cortex was later diagnosed as early Alzheimer's disease (AD) and mild cognitive impairment (MCI). MRI was negative in 6 patients and 3 of them had excellent clinical outcome while other 3 were diagnosed as hypercholesterolemia, early AD and MCI. Among 4 patients with positive MRI, 3 showed good clinical outcome and their MRI showed lesions at medial temporal cortex and/or vertebral artery. One patient with microcalcification at left putamen was diagnosed to have depression. Large cerebral perfusion defects on SPECT may herald psychiatric or neurodegenerative diseases of transient global amnesia patients which usually shows negative MRI

REM sleep enhancement and behavioral cataplexy following orexin (hypocretin)-II receptor antisense perfusion in the pontine reticular formation.

Science.gov (United States)

Thakkar, M M; Ramesh, V; Cape, E G; Winston, S; Strecker, R E; McCarley, R W

1999-01-01

Orexin (hypocretin)-containing neurons of the hypothalamus project to brainstem sites that are involved in the neural control of REM sleep, including the locus coeruleus, the dorsal raphe nucleus, the cholinergic zone of the mesopontine tegmentum, and the pontine reticular formation (PRF). Orexin knockout mice exhibit narcolepsy/cataplexy, and a mutant and defective gene for the orexin type II receptor is present in dogs with an inherited form of narcolepsy/cataplexy. However, the physiological systems mediating these effects have not been described. We reasoned that, since the effector neurons for the majority of REM sleep signs, including muscle atonia, were located in the PRF, this region was likely implicated in the production of these orexin-related abnormalities. To test this possibility, we used microdialysis perfusion of orexin type II receptor antisense in the PRF of rats. Ten to 24 hours after antisense perfusion, REM sleep increased two- to three-fold during both the light period (quiescent phase) and the dark period (active phase), and infrared video showed episodes of behavioral cataplexy. Moreover, preliminary data indicated no REM-related effects following perfusion with nonsense DNA, or when perfusion sites were outside the PRF. More work is needed to provide precise localization of the most effective site of orexin-induced inhibition of REM sleep phenomena.

Heterogeneity in cytokinetic, clonogenic, and radiation response induced by nutrient deprivation

International Nuclear Information System (INIS)

Grdina, D.J.; Williamson, K.D.; Johnson, T.S.; Sigdestad, C.P.

1986-01-01

A murine fibrosarcoma cell line (FSA 1233), with a capability to grow in vitro, was used to study biophysical heterogeneity induced by nutrient deprivation. Cell sub-populations were isolated by centrifuging cells through linear Renografin-density gradients. The effects of cell growth to late plateau phase on the cytokinetic, clonogenic, and radiation-survival characteristics were studied. It was observed that with increasing age of the cell culture, an increase in the proportion of relatively dense cells was associated with a decrease in plating efficiency. Cells collected at p=1.08 g/cm 3 have a plating efficiency of 0.2% compared with 0.01% for those isolated at p=1.16 g/cm 3 . Discrepancies were also seen between the tritiated thymidine labeling index (LI) and flow cytometry (FCM, % S phase) for cells collected throughout the gradient. The radiation sensitivities of selected cell populations isolated by density gradient centrifugation were determined and compared with data from a control plateau phase population. 15 refs., 4 figs., 1 tab

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

DEFF Research Database (Denmark)

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

1993-01-01

A new improved technique for whole-body perfusion-fixation of rats and other small animals is described. The driving force is a peristaltic pump which is feedback regulated by a pressure transducer that monitors the blood-perfusion pressure in the left ventricle of the heart. The primary perfusate...... to cannulate the heart; the outer and inner barrels of the cannula are connected to the peristaltic pump and to the pressure transducer, respectively. The tissue oxygen tension in the rat is monitored by a subcutaneous oxygen electrode. Measurements showed that tissue hypoxia/anoxia did not develop before......-fixative is composed of a blood substitute--13.3% oxygenated fluorocarbon FC-75--in 0.05 M cacodylate buffer (pH 7.4) with a 2% glutaraldehyde. The secondary perfusate-fixative is composed of 2% glutaraldehyde in 0.05 M cacodylate buffer (pH 7.4) with 20 mM CaCl2. A double-barrelled, self-holding cannula is used...

Pulmonary ventilation and perfusion imaging with dual-energy CT

Energy Technology Data Exchange (ETDEWEB)

Thieme, Sven F. [Klinikum Grosshadern, Department of Clinical Radiology, Ludwig Maximilians University, Muenchen (Germany); Klinikum Grosshadern, Institut fuer Klinische Radiologie, LMU Muenchen, Muenchen (Germany); Hoegl, Sandra; Fisahn, Juergen; Irlbeck, Michael [Klinikum Grosshadern, Department of Anesthesiology, Ludwig Maximilians University, Muenchen (Germany); Nikolaou, Konstantin; Maxien, Daniel; Reiser, Maximilian F.; Becker, Christoph R.; Johnson, Thorsten R.C. [Klinikum Grosshadern, Department of Clinical Radiology, Ludwig Maximilians University, Muenchen (Germany)

2010-12-15

To evaluate the feasibility of dual-energy CT (DECT) ventilation imaging in combination with DE perfusion mapping for a comprehensive assessment of ventilation, perfusion, morphology and structure of the pulmonary parenchyma. Two dual-energy CT acquisitions for xenon-enhanced ventilation and iodine-enhanced perfusion mapping were performed in patients under artificial respiration. Parenchymal xenon and iodine distribution were mapped and correlated with structural or vascular abnormalities. In all datasets, image quality was sufficient for a comprehensive image reading of the pulmonary CTA images, lung window images and pulmonary functional parameter maps and led to expedient results in each patient. With dual-source CT systems, DECT of the lung with iodine or xenon administration is technically feasible and makes it possible to depict the regional iodine or xenon distribution representing the local perfusion and ventilation. (orig.)

Impairment of myocardial perfusion in children with sickle cell disease

International Nuclear Information System (INIS)

Maunoury, C.; Acar, P.; Montalembert, M. de

2003-01-01

While brain, bone and spleen strokes are well documented in children with sickle cell disease (SCD), impairment of myocardial perfusion is an unknown complication. Non invasive techniques such as exercise testing and echocardiography have a low sensitivity to detect myocardial ischemia in patients with SCD. We have prospectively assessed myocardial perfusion with Tl-201 SPECT in 23 patients with SCD (10 female, 13 male, mean age 12 ± 5 years). Myocardial SPECT was performed after stress and 3 hours later after reinjection on a single head gamma camera equipped with a LEAP collimator (64 x 64 matrix size format, 30 projections over 180 deg C, 30 seconds per step). Left ventricular ejection fraction (LVEF) was assessed by equilibrium radionuclide angiography at rest on the same day. Myocardial perfusion was impaired in 14/23 patients: 9 reversible defects and 5 fixed defects. The left ventricular cavity was dilated in 14/23 patients. The mean LVEF was 63 ± 9%. There was no relationship between myocardial perfusion and left ventricular dilation or function. The frequent impairment of myocardial perfusion in children with SCD could lead to suggest a treatment with hydroxyurea, an improvement of perfusion can be noted with hydroxyurea. (author)

Pulmonary O2 transfer during pulsatile and non-pulsatile perfusion.

Science.gov (United States)

Hauge, A; Nicolaysen, G

1980-07-01

The importance of the perfusion pattern for the oxygen transfer has been examined in isolated rabbit lungs perfused with plasma at constant volume inflow. The lungs were ventilated with constant tidal volume and constant end-expiratory pressure. Following a standardized rise in FIO2 the rate of rise in pulmonary venous PO2 (delta PO2/delta t) was measured during alternately pulsatile and non-pulsatile perfusion in normal lungs and in lungs made edematous by elevation of left atrial pressure. In normal lungs there was no difference in delta PO2/delta t when the two modes of perfusion were compared. In edematous lungs delta PO/delta t was statistically higher during pulsatile perfusion, indicating a beneficial effect of flow- and pressure pulsations, e.g. a better distribution of V/Q ratios throughout the lungs. In a separate series of expts. the advancement of a high O2 front through the airways was measured, and the two perfusion patterns compared. Since no difference was found, we suggest that the phenomenon of "cardiogenic gas mixing" in the airways in vivo is a result of a direct action of the heart on the lungs rather than arterial pulsations.

Cavitation enhances coagulated size during pulsed high-intensity focussed ultrasound ablation in an isolated liver perfusion system.

Science.gov (United States)

Zhao, Lu-Yan; Liu, Shan; Chen, Zong-Gui; Zou, Jian-Zhong; Wu, Feng

2016-11-24

To investigate whether cavitation enhances the degree of coagulation during pulsed high-intensity focussed ultrasound (HIFU) in an isolated liver perfusion system. Isolated liver was treated by pulsed HIFU or continuous-wave HIFU with different portal vein flow rates. The cavitation emission during exposure was recorded, and real-time ultrasound images were used to observe changes in the grey scale. The coagulation size was measured and calculated. HIFU treatment led to complete coagulation necrosis and total cell destruction in the target regions. Compared to exposure at a duty cycle (DC) of 100%, the mean volumes of lesions induced by 6 s exposure at DCs of 50% and 10% were significantly larger (P cavitation activity for the pulsed-HIFU (P > .05). For continuous-wave HIFU exposure, there was a significant decrease in the necrosis volume and cavitation activity for exposure times of 1, 2, 3, 4, and 6 s with increasing portal perfusion rates. Perfusion flow rates negatively influence cavitation activity and coagulation volume. Ablation is significantly enhanced during pulsed HIFU exposure compared with continuous-wave HIFU.

ST-vector orientation and location of myocardial perfusion defects during exercise

International Nuclear Information System (INIS)

Simoons, M.L.; Withagen, A.; Vinke, R.; Kooy, P.; Bakker, W.; Erasmus Universiteit, Rotterdam

1978-01-01

In 34 patients with chest pain the spatial orientation of the ST-vectors in the exercise electrocardiogramm 30 and 80 msec after the end of QRS were compared with the location of exercise induced local defects of myocardial uptake of 201 Tl. The following results were obtained: 1. The sensitivity and specifity of myocardial perfusion imaging after exercise were the same as those of exercise electrocardiograms; 2. No relation could be observed beween the location of reduced 201 Tl uptake during exercise and the spatial orientation of the ST-vectors. (orig.) [de

Clinical investigation of large perfusion defect cases with 201Tl exercise myocardial scintigraphy

International Nuclear Information System (INIS)

Morota, Motoi; Kobayashi, Yasuhiko

1999-01-01

We investigated retrospectively the clinical significance of large perfusion defect on 201 Thallium myocardial scintigraphy from the records of 833 patients during the past 3 years from 1991 to 1994. The patients were divided into 3 groups according to the extent of perfusion defect; cases with normal perfusion (n=561), with small perfusion defect (n=211) and with large perfusion defect (n=61). We found that the proportions of cases with large perfusion defect was significantly larger than that of cases with small perfusion defect in myocardial disease (MD; hypertrophic cardiomyopathy, dilated cardiomyopathy, and post myocarditis combined) (P 201 Thallium myocardial scintigraphy and that complication of diabetes mellitus and clinical symptoms may be useful in differentiating IHD from MD. (author)

Feasibility and diagnostic power of transthoracic coronary Doppler for coronary flow velocity reserve in patients referred for myocardial perfusion imaging

Directory of Open Access Journals (Sweden)

Nylander Eva

2008-03-01

Full Text Available Abstract Background Myocardial perfusion imaging (MPI, using single photon emission computed tomography (SPECT is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Methods Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35–82, with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. Results We found that coronary flow velocity reserve (CFVR determined from diastolic measurements separated normal from abnormal MPI findings with statistical significance. TTDE identified coronary artery disease, defined from MPI, as reversible ischemia and/or permanent defect, with a sensitivity of 60% and a specificity of 79%. The positive predictive value was 43% and the negative predictive value was 88%. There was an overlap between groups which could be due to abnormal endothelial function in patients with normal myocardial perfusion having either hypertension or diabetes. Conclusion TTDE is an attractive non-invasive method to evaluate chest pain without the use of isotopes, but the diagnostic power is strongly dependent on the population investigated. Even in our heterogeneous clinical cardiac population, we found that CFVR>2 in the LAD excluded significant coronary artery disease detected by MPI.

Perfusion Electronic Record Documentation Using Epic Systems Software.

Science.gov (United States)

Riley, Jeffrey B; Justison, George A

2015-12-01

The authors comment on Steffens and Gunser's article describing the University of Wisconsin adoption of the Epic anesthesia record to include perfusion information from the cardiopulmonary bypass patient experience. We highlight the current-day lessons and the valuable quality and safety principles the Wisconsin-Epic model anesthesia-perfusion record provides.

Transport of benzo[alpha]pyrene in the dually perfused human placenta perfusion model: effect of albumin in the perfusion medium

DEFF Research Database (Denmark)

Mathiesen, Line; Rytting, Erik; Mose, Tina

2009-01-01

compared to other species; since it is available without major ethical obstacles, we have used the human placenta perfusion model to study transport from mother to foetus. Placentas were donated after births at Rigshospitalet in Copenhagen from pregnant mothers who signed an informed consent. Ba...

Impact of patient motion on myocardial perfusion SPECT

International Nuclear Information System (INIS)

Huang Kemin; Feng Yanlin; He Xiaohong; Wen Guanghua; Yu Fengwen; Liu Shusheng; Liu Dejun; Yuan Jianwei; Yang Ming

2008-01-01

Objective: It is well known that patient motion may cause artifacts in myocardial SPECT images and affect clinical diagnosis. The aim of the study was to evaluate the effects of motion on quality and semi-quantitative results of myocardial perfusion images. Methods: Six healthy volunteers un- derwent myocardial perfusion SPECT. The raw data in each case was manually shifted 1-6 frames and 1 4 pixels, respectively by using the motion correction software. The shifted raw data were then reconstructed. A semi-quantitative software was used to assess the myocardial perfusion of left ventricle. The quality and semi-quantitative results of the tomographic images reconstructed from the raw data with and without motion were compared and analyzed. SPSS 12.0 was used for data analysis. Results: There was no visible artifact and semi-quantitative difference on the data with 1 frame and (or) 1 pixel shift when compared with the original data without shift. The image artifacts became significantly deteriorated when the number of flame and (or) pixel shift was increased. In general, the image artifact of inferior and posterior wall was related to the upward shift, and that of anterior and infero-posterior wall was related to the downward shift, that of septal, anterior, infero-postefior wall and apex was related to right-ward shift, and the septal and infero-posterior wall was related to the left-ward shift. The differences along the x-axis shift were more prominent than that of the y-axis (t=2.848, P<0.01), and the differences in the downward and rightward shift were more severe than the upward and leftward shift (t=2.941, 6.598; all P<0.01), respectively. Conclusions: Image artifacts became significant when there was motion induced by manual shift of more than one flame and (or) one pixel. Different motion directions were closely related to different segments of left ventricle. (authors)

A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion

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Sandra Lindstedt

2013-01-01

Full Text Available To evaluate the lung function of donors after circulatory deaths (DCDs, ex vivo lung perfusion (EVLP has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP was increased to 10 cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10 cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2 was 18.5 ± 7.0 kPa before and 64.5 ± 6.0 kPa after the maneuver (P<0.001. In the conventional EVLP group, the PaO2 was 16.8 ± 3.1 kPa and 46.8 ± 2.7 kPa after the maneuver (P<0.01; P<0.01. In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs.

Paradoxical perfusion metrics of high-grade gliomas with an oligodendroglioma component: quantitative analysis of dynamic susceptibility contrast perfusion MR imaging

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Sunwoo, Leonard; Park, Sun-Won [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Choi, Seung Hong [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University, Center for Nanoparticle Research, Institute for Basic Science, and School of Chemical and Biological Engineering, Seoul (Korea, Republic of); Yoo, Roh-Eul; Kang, Koung Mi; Yun, Tae Jin; Kim, Ji-hoon; Sohn, Chul-Ho [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae Min; Lee, Se-Hoon [Seoul National University Hospital, Department of Internal Medicine, Seoul (Korea, Republic of); Park, Chul-Kee [Seoul National University Hospital, Department of Neurosurgery, Seoul (Korea, Republic of); Won, Jae-Kyung; Park, Sung-Hye [Seoul National University Hospital, Department of Pathology, Seoul (Korea, Republic of); Kim, Il Han [Seoul National University Hospital, Department of Radiation Oncology, Seoul (Korea, Republic of)

2015-11-15

The aim of this study is to investigate perfusion characteristics of glioblastoma with an oligodendroglioma component (GBMO) compared with conventional glioblastoma (GBM) using dynamic susceptibility contrast (DSC) perfusion magnetic resonance (MR) imaging and microvessel density (MVD). The study was approved by the institutional review board. Newly diagnosed high-grade glioma patients were enrolled (n = 72; 20 GBMs, 14 GBMOs, 19 anaplastic astrocytomas (AAs), 13 anaplastic oligodendrogliomas (AOs), and six anaplastic oligoastrocytomas (AOAs)). All participants underwent preoperative MR imaging including DSC perfusion MR imaging. Normalized cerebral blood volume (nCBV) values were analyzed using a histogram approach. Histogram parameters were subsequently compared across each tumor subtype and grade. MVD was quantified by immunohistochemistry staining and correlated with perfusion parameters. Progression-free survival (PFS) was assessed according to the tumor subtype. GBMO displayed significantly reduced nCBV values compared with GBM, whereas grade III tumors with oligodendroglial components (AO and AOA) exhibited significantly increased nCBV values compared with AA (p < 0.001). MVD analyses revealed the same pattern as nCBV results. In addition, a positive correlation between MVD and nCBV values was noted (r = 0.633, p < 0.001). Patients with oligodendroglial tumors exhibited significantly increased PFS compared with patients with pure astrocytomas in each grade. In contrast to grade III tumors, the presence of oligodendroglial components in grade IV tumors resulted in paradoxically reduced perfusion metrics and MVD. In addition, patients with GBMO exhibited a better clinical outcome compared with patients with GBM. (orig.)

Prognostic Value of Normal Perfusion but Impaired Left Ventricular Function in the Diabetic Heart on Quantitative Gated Myocardial Perfusion SPECT

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Jeong, Hwanjeong; Choi, Sehun; Han, Yeonhee [Research Institute of Chonbuk National Univ. Medical School and Hospitial, Jeonju (Korea, Republic of); Lee, Dong Soo; Lee, Hoyoung; Chung, Junekey [Seoul National Univ., Seoul (Korea, Republic of)

2013-09-15

This study aimed at identifying the predictive parameters on quantitative gated myocardial perfusion single-photon emission computed tomography (QG-SPECT) in diabetic patients with normal perfusion but impaired function. Methods Among the 533 consecutive diabetic patients, 379 patients with normal perfusion on rest Tl-201/dipyridamole-stress Tc-{sup 99m} sestamibi Gated SPECT were enrolled. Patients were grouped into those with normal post-stress left ventricular function (Group I) and those with impaired function (EF <50 or impaired regional wall motion, Group II). We investigated cardiac events and cause of death by chart review and telephone interview. Survival analysis and Cox proportional hazard model analysis were performed. Between the Group I and II, cardiac events as well as chest pain symptoms, smoking, diabetic complications were significantly different (P<0.05). On survival analysis, event free survival rate in Group II was significantly lower than in Group I (P=0.016). In univariate Cox proportional hazard analysis on overall cardiac event, Group (II over I), diabetic nephropathy, summed motion score (SMS), summed systolic thickening score (STS), numbers of abnormal segmental wall motion and systolic thickening predicted more cardiac events (P<0.05). Multivariate analysis showed that STS was the only independent predictor cardiac event. The functional parameter, especially summed systolic thickening score on QG-SPECT had prognostic values, despite normal perfusion, in predicting cardiac events in diabetic patients, and QG-SPECT provides clinically useful risk stratification in diabetic patients with normal perfusion.

Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography

DEFF Research Database (Denmark)

Rochitte, Carlos E; George, Richard T; Chen, Marcus Y

2014-01-01

AIMS: To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed...... emission computed tomography (SPECT/MPI). Sixteen centres enroled 381 patients who underwent combined CTA-CTP and SPECT/MPI prior to conventional coronary angiography. All four image modalities were analysed in blinded independent core laboratories. The prevalence of obstructive CAD defined by combined ICA...... tomography (SPECT). METHODS AND RESULTS: We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ≥50% stenosis by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon...

Simple motion correction strategy reduces respiratory-induced motion artifacts for k-t accelerated and compressed-sensing cardiovascular magnetic resonance perfusion imaging.

Science.gov (United States)

Zhou, Ruixi; Huang, Wei; Yang, Yang; Chen, Xiao; Weller, Daniel S; Kramer, Christopher M; Kozerke, Sebastian; Salerno, Michael

2018-02-01

Cardiovascular magnetic resonance (CMR) stress perfusion imaging provides important diagnostic and prognostic information in coronary artery disease (CAD). Current clinical sequences have limited temporal and/or spatial resolution, and incomplete heart coverage. Techniques such as k-t principal component analysis (PCA) or k-t sparcity and low rank structure (SLR), which rely on the high degree of spatiotemporal correlation in first-pass perfusion data, can significantly accelerate image acquisition mitigating these problems. However, in the presence of respiratory motion, these techniques can suffer from significant degradation of image quality. A number of techniques based on non-rigid registration have been developed. However, to first approximation, breathing motion predominantly results in rigid motion of the heart. To this end, a simple robust motion correction strategy is proposed for k-t accelerated and compressed sensing (CS) perfusion imaging. A simple respiratory motion compensation (MC) strategy for k-t accelerated and compressed-sensing CMR perfusion imaging to selectively correct respiratory motion of the heart was implemented based on linear k-space phase shifts derived from rigid motion registration of a region-of-interest (ROI) encompassing the heart. A variable density Poisson disk acquisition strategy was used to minimize coherent aliasing in the presence of respiratory motion, and images were reconstructed using k-t PCA and k-t SLR with or without motion correction. The strategy was evaluated in a CMR-extended cardiac torso digital (XCAT) phantom and in prospectively acquired first-pass perfusion studies in 12 subjects undergoing clinically ordered CMR studies. Phantom studies were assessed using the Structural Similarity Index (SSIM) and Root Mean Square Error (RMSE). In patient studies, image quality was scored in a blinded fashion by two experienced cardiologists. In the phantom experiments, images reconstructed with the MC strategy had higher

Hyperbaric oxygen therapy for the treatment of radiation-induced macular ischemia

Directory of Open Access Journals (Sweden)

Shamim A Haji

2010-05-01

Full Text Available Shamim A Haji1,2, Ronald EP Frenkel1,2,31Eye Research Foundation, Stuart, FL, USA; 2East Florida Eye Institute, Stuart, FL, USA; 3Bascom Palmer Eye Institute, Miami, FL, USAPurpose: To report a case of radiation-induced macular ischemia where vision and macular perfusion improved after hyperbaric oxygen (HBO therapy.Methods: A 62-year-old male patient developed radiation-induced macular ischemia after he was treated with radiation for brain glioma. The patient presented with best spectacle-corrected visual acuity (BSCVA acuity of 20/400 in his right eye. Optical coherence tomography (OCT showed central macular thickness of 468 μm. The patient received focal laser, intravitreal triamcinolone, and HBO therapy.Results: The patient’s vision improved from 20/400 to 20/100 after focal laser and intravitreal triamcinolone. His central macular thickness improved from 468 μm to 132 μm. After receiving HBO therapy, his VA improved to 20/50 and fluorescein angiography showed improvement in macular perfusion.Conclusion: HBO therapy improves macular perfusion in patients with radiation-induced macular ischemia.Keywords: macular ischemia, visual acuity, hyperbaric oxygen therapy, macular perfusion

Rest-Stress Limb Perfusion Imaging in Humans with Contrast Ultrasound Using Intermediate-Power Imaging and Microbubbles Resistant to Inertial Cavitation.

Science.gov (United States)

Davidson, Brian P; Hodovan, James; Belcik, J Todd; Moccetti, Federico; Xie, Aris; Ammi, Azzdine Y; Lindner, Jonathan R

2017-05-01

Contrast-enhanced ultrasound (CEU) limb perfusion imaging is a promising approach for evaluating peripheral artery disease (PAD). However, low signal enhancement in skeletal muscle has necessitated high-power intermittent imaging algorithms, which are not clinically feasible. We hypothesized that CEU using a combination of intermediate power and a contrast agent resistant to inertial cavitation would allow real-time limb stress perfusion imaging. In normal volunteers, CEU of the calf skeletal muscle was performed on separate days with Sonazoid, Optison, or Definity. Progressive reduction in the ultrasound pulsing interval was used to assess the balance between signal enhancement and agent destruction at escalating mechanical indices (MI, 0.1-0.4). Real-time perfusion imaging at MI 0.1-0.4 using postdestructive replenishment kinetics was performed at rest and during 25 W plantar flexion contractile exercise. For Optison, limb perfusion imaging was unreliable at rest due to very low signal enhancement generated at all MIs and was possible during exercise-induced hyperemia only at MI 0.1 due to agent destruction at higher MIs. For Definity, signal intensity progressively increased with MI but was offset by microbubble destruction, which resulted in modest signal enhancement during CEU perfusion imaging and distortion of replenishment curves at MI ≥ 0.2. For Sonazoid, there strong signal enhancement at MI ≥ 0.2, with little destruction detected only at MI 0.4. Accordingly, high signal intensity and nondistorted perfusion imaging was possible at MI 0.2-0.3 and detected an 8.0- ± 5.7-fold flow reserve. Rest-stress limb perfusion imaging in humans with real-time CEU, which requires only seconds to perform, is possible using microbubbles with viscoelastic properties that produce strong nonlinear signal generation without destruction at intermediate acoustic pressures. Copyright © 2016 American Society of Echocardiography. All rights reserved.

[Intratympanic corticosteroid perfusion in the therapy of Meniere's disease].

Science.gov (United States)

Sanković-Babić, Snezana; Kosanović, Rade; Ivanković, Zoran; Babac, Snezana; Tatović, Milica

2014-01-01

Over the last two decades the intratympanic perfusion of corticosteroids has been used as a minimally invasive surgical therapy of Meniere's disease. According to experimental studies the antiinflammatory, immunoprotective, antioxidant and neuroprotective role of the locally perfused corticosteroids was noticed in the inner ear structures. The recovery of action potentials in the cells of the Corti organ was confirmed as well as a decreased expression of aquaporine-1, a glycoprotein responsible for labyrinth hydrops and N and K ions derangement. The study showed results of intratympanic perfusion therapy with dexamethasone in patients with retractable Meniere's disease who are resistant to conservative treatment. Single doses of 4 mg/ml dexamethasone were given intratympanically in 19 patients with retractable Meniere's disease. Six single successive doses of dexamethasone were administered in the posteroinferior quadrant of the tympanic membrane. Follow-up of the patients was conducted by using a clinical questionnaire a month after completed perfusion series as well as on every third month up to one year. One month after completed first course of perfusions, in 78% of patients, vertigo problems completely ceased or were markedly reduced. The recovery of hearing function was recorded in 68% and marked tinnitus reduction in 84% of patients. After a year of follow-up, in 63% of patients the reduction of vertigo persisted, while hearing function was satisfactory in 52%. Tinitus reduction was present in 73% of patients. Intratympanic perfusion of dexamethasone in patients with Meniere's disease is a minimally invasive therapeutic method that contributes to the reduction of the intensity of vertigo recurrent attacks, decrease of the intensity of tinnitus and improvement of the average hearing threshold. Patients with chronic diseases and Meniere's disease who are contraindicted for systemic administration of cortocosteroids (hypertension, diabetes, glaucoma, peptic

Mucosal blood flow measurements using laser Doppler perfusion monitoring

Institute of Scientific and Technical Information of China (English)

Dag Arne Lihaug Hoff; Hans Gregersen; Jan Gunnar Hatlebakk

2009-01-01

Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insufficiency of perfusion, is a common mechanism for tissue death or degeneration, and at a lower threshold, a mechanism for the generation of sensory signalling including pain. It is of considerable interest to study perfusion of peripheral abdominal tissues in a variety of circumstances. Microvascular disease of the abdominal organs has been implicated in the pathogenesis of a variety of disorders, including peptic ulcer disease, inflammatory bowel disease and chest pain. The basic principle of laser Doppler perfusion monitoring (LDPM) is to analyze changes in the spectrum of light reflected from tissues as a response to a beam of monochromatic laser light emitted. It reflects the total local microcirculatory blood perfusion, including perfusion in capillaries, arterioles, venules and shunts. During the last 20-25 years, numerous studies have been performed in different parts of the gastrointestinal (GI) tract using LDPM. In recent years we have developed a multi-modal catheter device which includes a laser Doppler probe, with the intent primarily to investigate patients suffering from functional chest pain of presumed oesophageal origin. Preliminary studies show the feasibility of incorporating LDPM into such catheters for performing physiological studies in the GI tract. LDPM has emerged as a research and clinical tool in preference to other methods; but, it is important to be aware of its limitations and account for them when reporting results.

WE-E-17A-06: Assessing the Scale of Tumor Heterogeneity by Complete Hierarchical Segmentation On MRI

International Nuclear Information System (INIS)

Gensheimer, M; Trister, A; Ermoian, R; Hawkins, D

2014-01-01

Purpose: In many cancers, intratumoral heterogeneity exists in vascular and genetic structure. We developed an algorithm which uses clinical imaging to interrogate different scales of heterogeneity. We hypothesize that heterogeneity of perfusion at large distance scales may correlate with propensity for disease recurrence. We applied the algorithm to initial diagnosis MRI of rhabdomyosarcoma patients to predict recurrence. Methods: The Spatial Heterogeneity Analysis by Recursive Partitioning (SHARP) algorithm recursively segments the tumor image. The tumor is repeatedly subdivided, with each dividing line chosen to maximize signal intensity difference between the two subregions. This process continues to the voxel level, producing segments at multiple scales. Heterogeneity is measured by comparing signal intensity histograms between each segmented region and the adjacent region. We measured the scales of contrast enhancement heterogeneity of the primary tumor in 18 rhabdomyosarcoma patients. Using Cox proportional hazards regression, we explored the influence of heterogeneity parameters on relapse-free survival (RFS). To compare with existing methods, fractal and Haralick texture features were also calculated. Results: The complete segmentation produced by SHARP allows extraction of diverse features, including the amount of heterogeneity at various distance scales, the area of the tumor with the most heterogeneity at each scale, and for a given point in the tumor, the heterogeneity at different scales. 10/18 rhabdomyosarcoma patients suffered disease recurrence. On contrast-enhanced MRI, larger scale of maximum signal intensity heterogeneity, relative to tumor diameter, predicted for shorter RFS (p=0.05). Fractal dimension, fractal fit, and three Haralick features did not predict RFS (p=0.09-0.90). Conclusion: SHARP produces an automatic segmentation of tumor regions and reports the amount of heterogeneity at various distance scales. In rhabdomyosarcoma, RFS was

Systemic perfusion: a method of enhancing relative tumor uptake of radiolabeled monoclonal antibodies

Energy Technology Data Exchange (ETDEWEB)

Wahl, R.L.; Piko, C.R.; Beers, B.A.; Geatti, O.; Johnson, J.; Sherman, P. (Michigan Univ., Ann Arbor, MI (USA). Dept. of Internal Medicine)

1989-01-01

The authors evaluated the feasibility of systemic vascular perfusion with saline (mimicking plasmapheresis) as a method to enhance tumor-specific monoclonal antibody (MoAb) tumor/background ratios. Perfusion in rats dropped whole-body 5G6.4 levels significantly at both perfusion times. The drop in whole-body radioactivity with perfusion was significantly greater for the animals perfused at 4 h post i.v. 5G6.4 antibody injection (48.3 +- 5.1%) than for those perfused at 24h post i.v. antibody injection (32.9 +- 2.9%). In the nude mice with ovarian cancer xenografts, gamma camera images of tumors were visually and quantitatively by computer image analysis enhanced by perfusion, with a 2.33-fold greater decline in whole body uptake than in the tumor. These studies show that much background antibody radioactivity can be removed using whole-body perfusion with saline, that the decline in whole body activity is larger with 4 than 24h perfusion and that tumor imaging can be enhanced by this approach. This and similar approaches that increase relative tumor antibody uptake such as plasmapheresis may be useful in imaging and therapy with radiolabeled antibodies.

Unequal diffusivities case of homogeneous–heterogeneous reactions within viscoelastic fluid flow in the presence of induced magnetic-field and nonlinear thermal radiation

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I.L. Animasaun

2016-06-01

Full Text Available This article presents the effects of nonlinear thermal radiation and induced magnetic field on viscoelastic fluid flow toward a stagnation point. It is assumed that there exists a kind of chemical reaction between chemical species A and B. The diffusion coefficients of the two chemical species in the viscoelastic fluid flow are unequal. Since chemical species B is a catalyst at the horizontal surface, hence homogeneous and heterogeneous schemes are of the isothermal cubic autocatalytic reaction and first order reaction respectively. The transformed governing equations are solved numerically using Runge–Kutta integration scheme along with Newton’s method. Good agreement is obtained between present and published numerical results for a limiting case. The influence of some pertinent parameters on skin friction coefficient, local heat transfer rate, together with velocity, induced magnetic field, temperature, and concentration profiles is illustrated graphically and discussed. Based on all of these assumptions, results indicate that the effects of induced magnetic and viscoelastic parameters on velocity, transverse velocity and velocity of induced magnetic field are almost the same but opposite in nature. The strength of heterogeneous reaction parameter is very helpful to reduce the concentration of bulk fluid and increase the concentration of catalyst at the surface.

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

Science.gov (United States)

Forsythe, Rachael O; Hinchliffe, Robert J

2016-01-01

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

Regional assessment of treatment in lung cancer using lung perfusion and ventilation images

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