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Sample records for circumferential myocardial strain

  1. Assessment of Myocardial Contractile Function Using Global and Segmental Circumferential Strain following Intracoronary Stem Cell Infusion after Myocardial Infarction: MRI Feature Tracking Feasibility Study

    International Nuclear Information System (INIS)

    Background. Magnetic resonance imaging (MRI) strain analysis is a sensitive method to assess myocardial function. Our objective was to define the feasibility of MRI circumferential strain (εcc) analysis in assessing subtle changes in myocardial function following stem cell therapy. Methods and Results. Patients in the Amorcyte Phase I trial were randomly assigned to treatment with either autologous bone-marrow-derived stem cells infused into the infarct-related artery 5 to 11 days following primary PCI or control. MRI studies were obtained at baseline, 3, and 6 months. εcc was measured in the short axis views at the base, mid and apical slices of the left ventricle (LV) for each patient (13 treatments and 10 controls). Mid-anterior LV εcc improved between baseline −18.5 ± 8.6 and 3 months −22.6 ± 7.0, P = 0.03. There were no significant changes in εcc at 3 months and 6 months compared to baseline for other segments. There was excellent intraobserver and interobserver agreement for basal and mid circumferential strain. Conclusion. MRI segmental strain analysis is feasible in assessment of regional myocardial function following cell therapy with excellent intra- and inter-observer variability's. Using this method, a modest interval change in segmental εcc was detected in treatment group

  2. Circumferential Strain Can Be Used to Detect Lipopolysaccharide-Induced Myocardial Dysfunction and Predict the Mortality of Severe Sepsis in Mice

    Science.gov (United States)

    Chu, Ming; Gao, Yao; Zhou, Bin; Wu, Bingruo; Wang, Junhong; Xu, Di

    2016-01-01

    Background Sepsis-induced myocardial dysfunction is a common and severe complication of septic shock. However, conventional echocardiography often fails to reveal myocardial depression in severe sepsis. Recently, strain measurements based on speckle tracking echocardiography (STE) have been used to evaluate cardiac function. Aims To investigate the role of STE in detecting lipopolysaccharide (LPS)-induced cardiac dysfunction, M-mode and 2-D echocardiography were used in LPS-treated mice. Methods The mice were treated with a 10mg/kg (n = 10), 20mg/kg (n = 10) or 25mg/kg LPS (n = 30) to induce cardiac dysfunction. Subsequently, the ejection fraction (EF) and fractional shortening (FS) were measured with standard M-mode tracings, whereas the circumferential (Scirc) and radial strain (Srad) were measured with STE. Serum biochemical and cardiac histopathological examinations were performed to assess sepsis-induced myocardial injury. Results 20mg/kg LPS resulted in more deterioration, myocardial damage and cardiac contractile dysfunction based on serum biochemical and histological examinations. The mice that were subjected to 20mg/kg LPS exhibited reduced Scirc but no reduction in Srad, whereas on conventional echocardiography, the ejection fraction (EF) and fractional shortening (FS) were similar in the 10mg/kg and 20mg/kg groups. Moreover, Scirc was positively correlated with body temperature in the mice at 20 h after LPS injection (r = 0.746, p = 0.001), but no significant correlation was observed between Srad and body temperature (r = 0.356, p = 0.123). Moreover, the mice with high Scirc (-5.9% to -10.4%) exhibited reduced mortality following the administration of 25mg/kg LPS (p = 0.03) compared with the low-strain group (-2% to -5.9%). Conclusions Taken together, our findings indicate that circumferential strain is a specific and reliable indicator for evaluating LPS-induced cardiac dysfunction in mice. PMID:27177150

  3. Magnetic resonance-derived circumferential strain provides a superior and incremental assessment of improvement in contractile function in patients early after ST-segment elevation myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Dennis T.L.; Psaltis, Peter J. [University of Adelaide, Discipline of Medicine, Adelaide (Australia); South Australian Health and Medical Research Institute (SAHMRI), Adelaide (Australia); Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre)Monash University and Monash Heart, Clayton, VIC (Australia); Leong, Darryl P.; Weightman, Michael J.; Richardson, James D.; Worthley, Matthew I.; Worthley, Stephen G. [University of Adelaide, Discipline of Medicine, Adelaide (Australia); Dundon, Benjamin K.; Leung, Michael C.H.; Meredith, Ian T. [Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre)Monash University and Monash Heart, Clayton, VIC (Australia)

    2014-06-15

    We evaluate whether circumferential strain derived from grid-tagged CMR is a better method for assessing improvement in segmental contractile function after STEMI compared to late gadolinium enhancement (LGE). STEMI patients post primary PCI underwent baseline CMR (day 3) and follow-up (day 90). Cine, grid-tagged and LGE images were acquired. Baseline LGE infarct hyperenhancement was categorised as ≤25 %, 26-50 %, 51-75 % and >75 % hyperenhancement. The segmental baseline circumferential strain (CS) and circumferential strain rate (CSR) were calculated from grid-tagged images. Segments demonstrating an improvement in wall motion of ≥1 grade compared to baseline were regarded as having improved segmental contractile-function. Forty-five patients (aged 58 ± 12 years) and 179 infarct segments were analysed. A baseline CS cutoff of -5 % had sensitivity of 89 % and specificity of 70 % for detection of improvement in segmental-contractile-function. On receiver-operating characteristic analysis for predicting improvement in contractile function, AUC for baseline CS (0.82) compared favourably to LGE hyperenhancement (0.68), MVO (0.67) and baseline-CSR (0.74). On comparison of AUCs, baseline CS was superior to LGE hyperenhancement and MVO in predicting improvement in contractile function (P < 0.001). On multivariate-analysis, baseline CS was the independent predictor of improvement in segmental contractile function (P < 0.001). Grid-tagged CMR-derived baseline CS is a superior predictor of improvement in segmental contractile function, providing incremental value when added to LGE hyperenhancement and MVO following STEMI. (orig.)

  4. Accelerated circumferential strain quantification of the left ventricle using CIRCOME: simulation and factor analysis

    Science.gov (United States)

    Moghaddam, Abbas N.; Finn, J. Paul

    2008-03-01

    Circumferential strain of the left ventricle reflects myocardial contractility and is considered a key index of cardiac function. It is also an important parameter in the quantitative evaluation of heart failure. Circumferential compression encoding, CIRCOME, is a novel method in cardiac MRI to evaluate this strain non-invasively and quickly. This strain encoding technique avoids the explicit measurement of the displacement field and does not require calculation of strain through spatial differentiation. CIRCOME bypasses these two time-consuming and noise sensitive steps by directly using the frequency domain (k-space) information from radially tagged myocardium, before and after deformation. It uses the ring-shaped crown region of the k-space, generated by the taglines, to reconstruct circumferentially compression-weighted images of the heart before and after deformation. CIRCOME then calculates the circumferential strain through relative changes in the compression level of corresponding regions before and after deformation. This technique can be implemented in 3D as well as 2D and may be employed to estimate the overall global or regional circumferential strain. The main parameters that affect the accuracy of this method are spatial resolution, signal to noise ratio, eccentricity of the center of radial taglines their fading and their density. Also, a variety of possible image reconstruction and filtering options may influence the accuracy of the method. This study describes the pulse sequence, algorithm, influencing factors and limiting criteria for CIRCOME and provides the simulated results.

  5. Feasibility of radial and circumferential strain analysis using 2D speckle tracking echocardiography in cats.

    Science.gov (United States)

    Takano, Hiroshi; Isogai, Tomomi; Aoki, Takuma; Wakao, Yoshito; Fujii, Yoko

    2015-02-01

    The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM were performed. Segmental assessments of left ventricle (LV) wall for strain and strain rate variables in cats with HCM were also performed. As a result, technically adequate images were obtained in 97.6% of the segments for STE analysis. Sedation using buprenorphine and acepromazine did not affect any global strain nor strain rate variable. In LV segments of cats with HCM, reduced segmental radial strain and strain rate variables had significantly related with segmental LV hypertrophy. It is concluded that STE analysis using short axis images of LV appeared to be clinically feasible in cats, having the possibility to be useful for detecting myocardial dysfunctions in cats with diseased heart. PMID:25373881

  6. Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

    International Nuclear Information System (INIS)

    Highlights: • Infarcted segments could be differentiated from non-ischemic and ischemic segments with high sensitivity and specificity under at rest conditions. • The time-to-peak circumferential strain values in infarcted segments were more significantly delayed than those in non-ischemic and ischemic segments. • Both circumferential strain and circumferential systolic strain rate values under ATP-stress conditions were significantly lower in ischemic segments than in non-ischemic segments. • Subtracting stress and rest circumferential strain had a higher diagnostic capability for ischemia relative to only utilizing rest or ATP-stress circumferential strain values. • A circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium. - Abstract: Purpose: We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. Methods: In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n = 485), ischemic (n = 74), or infarcted (n = 49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. Results: A cutoff value of −12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3 ms for time-to-peak CS at rest

  7. Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masashi, E-mail: m.nakamura1230@gmail.com [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan); Kido, Tomoyuki [Department of Radiology, Saiseikai Matsuyama Hospital, Ehime 791-0295 (Japan); Kido, Teruhito; Tanabe, Yuki; Matsuda, Takuya; Nishiyama, Yoshiko; Miyagawa, Masao; Mochizuki, Teruhito [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan)

    2015-08-15

    Highlights: • Infarcted segments could be differentiated from non-ischemic and ischemic segments with high sensitivity and specificity under at rest conditions. • The time-to-peak circumferential strain values in infarcted segments were more significantly delayed than those in non-ischemic and ischemic segments. • Both circumferential strain and circumferential systolic strain rate values under ATP-stress conditions were significantly lower in ischemic segments than in non-ischemic segments. • Subtracting stress and rest circumferential strain had a higher diagnostic capability for ischemia relative to only utilizing rest or ATP-stress circumferential strain values. • A circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium. - Abstract: Purpose: We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. Methods: In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n = 485), ischemic (n = 74), or infarcted (n = 49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. Results: A cutoff value of −12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3 ms for time-to-peak CS at rest

  8. Feasibility of radial and circumferential strain analysis using 2D speckle tracking echocardiography in cats

    OpenAIRE

    Takano, Hiroshi; ISOGAI, Tomomi; Aoki, Takuma; WAKAO, Yoshito; Fujii, Yoko

    2014-01-01

    The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM...

  9. Myocardial perfusion changes following 1 year of exercise training assessed by thallium-201 circumferential count profiles

    International Nuclear Information System (INIS)

    The effect of exercise training on myocardial perfusion was assessed using initial and 1-year thallium-201 (Tl-201) exercise studies in 56 patients with stable coronary artery disease (CAD). Subjects had been randomized into a trained group participating in supervised exercise three times per week and a control group. Indices (non-dimensional units) based on computer-analyzed circumferential count profile from nine regions of the heart, assessed in three projections, were used to eliminate observer bias and more accurately quantitate Tl-201 distribution and 4-hour washout. There was serial improvement of the global distribution count profiles in 21 of 27 (77.8%) of the trained and in 9 of 29 (31.0%) of the control subjects (p less than 0.001). The mean interval change in global initial distribution over the year period was 5 +/- 13 (mean +/- SD) in the trained and -6 +/- 14 in the control groups (p less than 0.003). The mean initial distribution of the trained group had improvement in all nine regions (significant in three), while the control group showed mean improvement in only one of nine regions. Additionally, the trained group showed improvement in the mean washout in five of nine regions (significant in three), while no mean regional washout improvement occurred in the control group. Thus, in this group of patients with stable CAD, exercise training resulted in apparently improved cardiac perfusion evidenced by enhance Tl-201 uptake and washout

  10. Myocardial Strain and Strain Rate Imaging: Comparison between Doppler Derived Strain Imaging and Speckle Tracking Echocardiography

    Directory of Open Access Journals (Sweden)

    Anita Sadeghpour

    2013-05-01

    Full Text Available Regional myocardial function has been traditionally assessed by visual estimation (1. Echocardiographic strain imaging which is known as deformation imaging, has been emerged as a quantitative technique to accurately estimate regional myocardial function and contractility. Currently, strain imaging has been regarded as a research tool in the most echocardiography laboratories. However, in recent years, strain imaging has gain momentum in daily clinical practice (2. The following two techniques have dominated the research arena of echocardiography: (1 Doppler based tissue velocity measurements, frequently referred to tissue Doppler or myocardial Doppler, and (2 speckle tracking on the basis of displacement measurements (3. Over the past two decades, Tissue Doppler Imaging (TDI and Doppler –derived strain (S and strain rate (SR imaging were introduced to quantify regional myocardial function. However, Doppler–derived strain variables faced criticisms, with regard to the angle dependency, noise interference, and substantial intraobserver and interobserver variability. The angle dependency is the major weakness of Doppler based methodology; however, it has the advantage of online measurements of velocities and time intervals with excellent temporal resolution, which is essential for the assessment of ischemia (4. Speckle-tracking echocardiography (STE or Non Doppler 2D strain echocardiography is a relatively new, largely angle-independent technique that analyzes motion by tracking natural acoustic reflections and interference patterns within an ultrasonic window. The image-processing algorithm tracks elements with approximately 20 to 40 pixels containing stable patterns and are described as ‘‘speckles’’ or ‘‘fingerprints’’. The speckles seen in grayscale B-mode (2D images are tracked consecutively frame to frame (5, 6. Assessment of 2D strain by STE is a semiautomatic method that requires definition of the myocardium

  11. Myocardial Strain and Strain Rate in Kawasaki Disease: Range, Recovery, and Relationship to Systemic Inflammation/Coronary Artery Dilation

    Science.gov (United States)

    Frank, Benjamin; Davidson, Jesse; Tong, Suhong; Martin, Blake; Heizer, Heather; Anderson, Marsha S; Glode, Mary P; Dominguez, Samuel R; Jone, Pei-Ni

    2016-01-01

    Background Kawasaki Disease (KD), a systemic vasculitis of medium sized vessels, is the most common cause of acquired heart disease among children in the developed world. Some KD patients demonstrate echocardiographic evidence of depressed myocardial mechanics. However, the incidence, etiology, and reversibility of abnormal mechanics in KD patients remain undefined. Methods and results We retrospectively studied 41 KD patients and measured myocardial strain and strain rate by velocity vector imaging from pre-treatment and convalescent echocardiograms. Pre-treatment procalcitonin, C-reactive protein (CRP), and coronary artery z-scores were obtained in all patients and compared between the groups with preserved versus depressed acute phase mechanics. The change in mechanics between the acute and convalescent phases was also assessed. Patients with initially low longitudinal strain improved by the convalescent period (mean difference - 4.0%; p<0.005) with the greatest improvement occurring in patients with the lowest initial strain (−7.3%; p<0.05). Patients with higher initial strain did not change significantly by the convalescent period. Patients with lower longitudinal and circumferential strain demonstrated higher median procalcitonin levels (1.2 vs. 0.3 ng/mL; p<0.05 and 1.8 vs. 0.4 ng/mL; p<0.05 respectively) and a trend towards higher CRP, but no difference in coronary artery z-scores. Strain rate was not associated with inflammatory markers or coronary artery z-scores. Conclusions The range of strain found in our cohort was large. Improvement in mean strain was driven primarily by patients with lower initial strain. Lower strain was associated with increased markers of systemic inflammation, but not proximal coronary artery changes.

  12. Identification and further differentiation of subendocardial and transmural myocardial infarction by fast strain-encoded (SENC) magnetic resonance imaging at 3.0 tesla

    International Nuclear Information System (INIS)

    To investigate whether subendocardial and transmural myocardial infarction can be identified and differentiated using the peak circumferential and longitudinal strains measured by fast strain-encoded (SENC). Nineteen patients with ischemic heart diseases underwent imaging with fast SENC and late gadolinium enhancement (LGE) MRI at 3 T. Fast SENC measurements were performed in three short-axis slices (basal, mid-ventricular and apical levels) and one long-axis view (four-chamber) to assess peak longitudinal and circumferential systolic strains. All patients showed myocardial infarction with an average of 7 positive LGE segments. A total of 304 segments for longitudinal strains (LS) and 114 segments for circumferential strains (CS) could be analysed. Positive LGE segments showed lower peak CS and LS compared with the no LGE segments (P < 0.0001 for both). Segments with subendocardial infarction showed reduced CS and LS compared with the no LGE segments (P < 0.0001 for both). There was a significant difference in CS between subendocardial and transmural infarct segments (P = 0.03), but no significant difference in LS between them (P = 0.64). Fast SENC can identify old myocardial infarction and differentiate subendocardial from transmural infarction. (orig.)

  13. Moderate ischemic mitral regurgitation after postero-lateral myocardial infarction in sheep alters left ventricular shear but not normal strain in the infarct and infarct borderzone

    Science.gov (United States)

    Ge, Liang; Wu, Yife; Soleimani, Mehrdad; Khazalpour, Michael; Takaba, Kiyoaki; Tartibi, Mehrzad; Zhang, Zhihong; Acevedo-Bolton, Gabriel; Saloner, David A.; Wallace, Arthur W.; Mishra, Rakesh; Grossi, Eugene A.; Guccione, Julius M.; Ratcliffe, Mark B.

    2016-01-01

    Background Chronic ischemic mitral regurgitation (CIMR: MR) is associated with poor outcome. Left ventricular (LV) strain after postero-lateral myocardial infarction (MI) may drive LV remodeling. Although moderate CIMR has been previously shown to effect LV remodeling, the effect of CIMR on LV strain after postero-lateral MI remains unknown. We tested the hypothesis that moderate CIMR alters LV strain after postero-lateral MI. Methods/Results Postero-lateral MI was created in 10 sheep. Cardiac MRI with tags was performed 2 weeks before and 2, 8 and 16 weeks after MI. LV and right ventricular (RV) volumes were measured and regurgitant volume indexed to body surface area (BSA; RegurgVolume Index) calculated as the difference between LV and RV stroke volumes / BSA. Three-dimensional strain was calculated. Circumferential (Ecc)and longitudinal (Ell) strains were reduced in the infarct proper, MI borderzone (BZ) and remote myocardium 16 weeks after MI. In addition, radial circumferential (Erc) and radial longitudinal (Erl) shear strains were reduced in remote myocardium but increased in the infarct and BZ 16 weeks after MI. Of all strain components, however, only Erc was effected by RegurgVolume Index (p=0.0005). There was no statistically significant effect of RegurgVolume Index on Ecc, Ell, Erl, or circumferential longitudinal shear strain (Ecl). Conclusions Moderate CIMR alters radial circumferential shear strain after postero-lateral MI in the sheep. Further studies are needed to determine the effect of shear strain on myocyte hypertrophy and the effect of mitral repair on myocardial strain. PMID:26857634

  14. Metabolic Syndrome, Strain, and Reduced Myocardial Function: Multi-Ethnic Study of Atherosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, André Luiz Cerqueira de, E-mail: andrealmeida@cardiol.br [Johns Hopkins University, Baltimore, MD (United States); Universidade Estadual de Feira de Santana, Bahia (Brazil); Teixido-Tura, Gisela; Choi, Eui-Young; Opdahl, Anders; Fernandes, Verônica R. S. [Johns Hopkins University, Baltimore, MD (United States); Wu, Colin O. [National Heart, Lung and Blood Institute, Bethesda, MD (United States); Bluemke, David A. [National Institutes of Health Clinical Center, National Institute for Biomedical Imaging and Bioengineering, Bethesda, MD (United States); Lima, João A. C. [Johns Hopkins University, Baltimore, MD (United States)

    2014-04-15

    Subclinical cardiovascular disease is prevalent in patients with Metabolic Syndrome (MetSyn). Left ventricular (LV) circumferential strain (ε{sub CC}) and longitudinal strain (ε{sub LL}), assessed by Speckle Tracking Echocardiography (STE), are indices of systolic function: shortening is indicated by negative strain, and thus, the more negative the strain, the better the LV systolic function. They have been used to demonstrate subclinical ventricular dysfunction in several clinical disorders. We hypothesized that MetSyn is associated with impaired myocardial function, as assessed by STE. We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent STE and were evaluated for all MetSyn components. Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ± SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had lower ε{sub CC} and lower ε{sub LL} than those without MetSyn (-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9% ± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was similar in both groups (p = 0.09). In multivariate analysis, MetSyn was associated with less circumferential myocardial shortening as indicated by less negative ε{sub CC} (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95% CI: 0.01-0.03, p = 0.02) were significantly associated with less longitudinal myocardial shortening as indicated by less negative ε{sub LL} after adjustment for ethnicity, LVEF, and creatinine. Left ventricular ε{sub CC} and ε{sub LL}, markers of subclinical cardiovascular disease, are impaired in asymptomatic individuals with MetSyn and no history of myocardial infarction, heart failure, and/or LVEF < 50%.

  15. Metabolic Syndrome, Strain, and Reduced Myocardial Function: Multi-Ethnic Study of Atherosclerosis

    International Nuclear Information System (INIS)

    Subclinical cardiovascular disease is prevalent in patients with Metabolic Syndrome (MetSyn). Left ventricular (LV) circumferential strain (εCC) and longitudinal strain (εLL), assessed by Speckle Tracking Echocardiography (STE), are indices of systolic function: shortening is indicated by negative strain, and thus, the more negative the strain, the better the LV systolic function. They have been used to demonstrate subclinical ventricular dysfunction in several clinical disorders. We hypothesized that MetSyn is associated with impaired myocardial function, as assessed by STE. We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent STE and were evaluated for all MetSyn components. Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ± SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had lower εCC and lower εLL than those without MetSyn (-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9% ± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was similar in both groups (p = 0.09). In multivariate analysis, MetSyn was associated with less circumferential myocardial shortening as indicated by less negative εCC (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95% CI: 0.01-0.03, p = 0.02) were significantly associated with less longitudinal myocardial shortening as indicated by less negative εLL after adjustment for ethnicity, LVEF, and creatinine. Left ventricular εCC and εLL, markers of subclinical cardiovascular disease, are impaired in asymptomatic individuals with MetSyn and no history of myocardial infarction, heart failure, and/or LVEF < 50%

  16. Inertial gas pressure and circumferential ridge sheath strains in CANFLEX-ACR fuel

    International Nuclear Information System (INIS)

    'Full text:' ACR-1000® fuel is designed to operate with an average exit burnup of up to 20 MWd/kgU. This average exit burnup is in excess of the burnup in current CANDU® designs. The increased burnup will result in higher fission product inventory. This paper reports the evaluation of fuel sheath strains and internal gas pressures during normal operation. The internal gas pressures and sheath strains are assessed using the ELESTRES computer code. Predicted strains and pressures have adequate margin to the relevant acceptance criteria.

  17. Left ventricular global longitudinal strain in acute myocardial infarction

    DEFF Research Database (Denmark)

    Ersbøll, Mads

    Systolic dysfunction, clinical heart failure and elevated levels of neurohormonal peptides are major predictors of adverse outcome after acute myocardial infarction (MI). In the present thesis we evaluated global longitudinal strain (GLS) in patients with acute MI in relation to neurohormonal...

  18. Interobserver, intraobserver and intrapatient reliability scores of myocardial strain imaging with 2-d echocardiography in patients treated with anthracyclines.

    NARCIS (Netherlands)

    Mavinkurve-Groothuis, A.M.C.; Weijers, G.; Groot-Loonen, J.J.; Pourier, M.S.; Feuth, A.B.; Korte, C.L. de; Hoogerbrugge, P.M.; Kapusta, L.

    2009-01-01

    Myocardial strain imaging with 2-D echocardiography is a relatively new noninvasive method to assess myocardial deformation. To determine the interobserver, intraobserver and intrapatient reliability scores, we evaluated myocardial strain measurements of 10 asymptomatic survivors of childhood cancer

  19. Strain Echocardiography Improves Risk Prediction of Ventricular Arrhythmias After Myocardial Infarction

    DEFF Research Database (Denmark)

    Haugaa, Kristina H; Grenne, Bjørnar L; Eek, Christian H;

    2013-01-01

    The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI).......The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI)....

  20. A new 2D-based method for myocardial velocity strain and strain rate quantification in a normal adult and paediatric population: assessment of reference values

    Directory of Open Access Journals (Sweden)

    Arcidiacono C

    2009-02-01

    Full Text Available Abstract Background Recent advances in technology have provided the opportunity for off-line analysis of digital video-clips of two-dimensional (2-D echocardiographic images. Commercially available software that follows the motion of cardiac structures during cardiac cycle computes both regional and global velocity, strain, and strain rate (SR. The present study aims to evaluate the clinical applicability of the software based on the tracking algorithm feature (studied for cardiology purposes and to derive the reference values for longitudinal and circumferential strain and SR of the left ventricle in a normal population of children and young adults. Methods 45 healthy volunteers (30 adults: 19 male, 11 female, mean age 37 ± 6 years; 15 children: 8 male, 7 female, mean age 8 ± 2 years underwent transthoracic echocardiographic examination; 2D cine-loops recordings of apical 4-four 4-chamber (4C and 2-chamber (2C views and short axis views were stored for off-line analysis. Computer analyses were performed using specific software relying on the algorithm of optical flow analysis, specifically designed to track the endocardial border, installed on a Windows™ based computer workstation. Inter and intra-observer variability was assessed. Results The feasibility of measurements obtained with tissue tracking system was higher in apical view (100% for systolic events; 64% for diastolic events than in short axis view (70% for systolic events; 52% for diastolic events. Longitudinal systolic velocity decreased from base to apex in all subjects (5.22 ± 1.01 vs. 1.20 ± 0.88; p Values of global systolic SR, both longitudinal and circumferential, were significantly higher in children than in adults (-1.3 ± 0.2, vs. -1.11 ± 0.2, p = 0.006; -1.9 ± 0.6 vs. -1.6 ± 0.5, p = 0.0265, respectively. No significant differences in longitudinal and circumferential systolic velocities were identified for any segment when comparing adults with children. Conclusion

  1. Comparison of cardiovascular magnetic resonance feature tracking and tagging for the assessment of left ventricular systolic strain in acute myocardial infarction

    International Nuclear Information System (INIS)

    Highlights: • We compared feature tracking (FT) and tagging quantification of myocardial strain in acute MI. • This is the first study assessing FT strain assessment in acute MI. • FT was more robust and had better myocardial tracking than tagging. • FT had better interobserver agreement and FT analysis was quicker. • FT has stronger correlation with global and segmental infarct size, area at risk (oedema), myocardial salvage and infarct transmurality. • FT is feasible in acute MI and is likely to become the preferred quantification method. - Abstract: Aims: To assess the feasibility of feature tracking (FT)-measured systolic strain post acute ST-segment elevation myocardial infarction (STEMI) and compare strain values to those obtained with tagging. Methods: Cardiovascular MRI at 1.5 T was performed in 24 patients, 2.2 days post STEMI. Global and segmental circumferential (Ecc) and longitudinal (Ell) strain were assessed using FT and tagging, and correlated with total and segmental infarct size, area at risk and myocardial salvage. Results: All segments tracked satisfactorily with FT (p < 0.001 vs. tagging). Total analysis time per patient was shorter with FT (38.2 ± 3.8 min vs. 63.7 ± 10.3 min, p < 0.001 vs. tagging). Global Ecc and Ell were higher with FT than with tagging, apart from FT Ecc using the average of endocardial and epicardial contours (−13.45 ± 4.1 [FT] vs. −13.85 ± 3.9 [tagging], p = 0.66). Intraobserver and interobserver agreement for global strain were excellent for FT (ICC 0.906–0.990) but interobserver agreement for tagging was lower (ICC < 0.765). Interobserver and intraobserver agreement for segmental strain was good for both techniques (ICC > 0.7) apart from tagging Ell, which was poor (ICC = 0.15). FT-derived Ecc significantly correlated with total infarct size (r = 0.44, p = 0.03) and segmental infarct extent (r = 0.44, p < 0.01), and best distinguished transmurally infarcted segments (AUC 0.77) and infarcted from

  2. Comparison of cardiovascular magnetic resonance feature tracking and tagging for the assessment of left ventricular systolic strain in acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Jamal N., E-mail: jk211@le.ac.uk; Singh, Anvesha, E-mail: as707@le.ac.uk; Nazir, Sheraz A., E-mail: sn191@le.ac.uk; Kanagala, Prathap, E-mail: pk214@le.ac.uk; Gershlick, Anthony H., E-mail: agershlick@aol.com; McCann, Gerry P., E-mail: gerry.mccann@uhl-tr.nhs.uk

    2015-05-15

    Highlights: • We compared feature tracking (FT) and tagging quantification of myocardial strain in acute MI. • This is the first study assessing FT strain assessment in acute MI. • FT was more robust and had better myocardial tracking than tagging. • FT had better interobserver agreement and FT analysis was quicker. • FT has stronger correlation with global and segmental infarct size, area at risk (oedema), myocardial salvage and infarct transmurality. • FT is feasible in acute MI and is likely to become the preferred quantification method. - Abstract: Aims: To assess the feasibility of feature tracking (FT)-measured systolic strain post acute ST-segment elevation myocardial infarction (STEMI) and compare strain values to those obtained with tagging. Methods: Cardiovascular MRI at 1.5 T was performed in 24 patients, 2.2 days post STEMI. Global and segmental circumferential (Ecc) and longitudinal (Ell) strain were assessed using FT and tagging, and correlated with total and segmental infarct size, area at risk and myocardial salvage. Results: All segments tracked satisfactorily with FT (p < 0.001 vs. tagging). Total analysis time per patient was shorter with FT (38.2 ± 3.8 min vs. 63.7 ± 10.3 min, p < 0.001 vs. tagging). Global Ecc and Ell were higher with FT than with tagging, apart from FT Ecc using the average of endocardial and epicardial contours (−13.45 ± 4.1 [FT] vs. −13.85 ± 3.9 [tagging], p = 0.66). Intraobserver and interobserver agreement for global strain were excellent for FT (ICC 0.906–0.990) but interobserver agreement for tagging was lower (ICC < 0.765). Interobserver and intraobserver agreement for segmental strain was good for both techniques (ICC > 0.7) apart from tagging Ell, which was poor (ICC = 0.15). FT-derived Ecc significantly correlated with total infarct size (r = 0.44, p = 0.03) and segmental infarct extent (r = 0.44, p < 0.01), and best distinguished transmurally infarcted segments (AUC 0.77) and infarcted from

  3. The intra-observer reproducibility of cardiovascular magnetic resonance myocardial feature tracking strain assessment is independent of field strength

    International Nuclear Information System (INIS)

    Background: Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a promising novel method for quantification of myocardial wall mechanics from standard steady-state free precession (SSFP) images. We sought to determine whether magnetic field strength affects the intra-observer reproducibility of CMR-FT strain analysis. Methods: We studied 2 groups, each consisting of 10 healthy subjects, at 1.5 T or 3 T Analysis was performed at baseline and after 4 weeks using dedicated CMR-FT prototype software (Tomtec, Germany) to analyze standard SSFP cine images. Right ventricular (RV) and left ventricular (LV) longitudinal strain (EllRV and EllLV) and LV long-axis radial strain (ErrLAX) were derived from the 4-chamber cine, and LV short-axis circumferential and radial strains (EccSAX, ErrSAX) from the short-axis orientation. Strain parameters were assessed together with LV ejection fraction (EF) and volumes. Intra-observer reproducibility was determined by comparing the first and the second analysis in both groups. Results: In all volunteers resting strain parameters were successfully derived from the SSFP images. There was no difference in strain parameters, volumes and EF between field strengths (p > 0.05). In general EccSAX was the most reproducible strain parameter as determined by the coefficient of variation (CV) at 1.5 T (CV 13.3% and 46% global and segmental respectively) and 3 T (CV 17.2% and 31.1% global and segmental respectively). The least reproducible parameter was EllRV (CV 1.5 T 28.7% and 53.2%; 3 T 43.5% and 63.3% global and segmental respectively). Conclusions: CMR-FT results are similar with reasonable intra-observer reproducibility in different groups of volunteers at 1.5 T and 3 T. CMR-FT is a promising novel technique and our data indicate that results might be transferable between field strengths. However there is a considerable amount of segmental variability indicating that further refinements are needed before CMR-FT can be fully

  4. Effects of steroids and angiotensin converting enzyme inhibition on circumferential strain in boys with Duchenne muscular dystrophy: a cross-sectional and longitudinal study utilizing cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Kinnett Kathi J

    2011-10-01

    Full Text Available Abstract Background Steroid use has prolonged ambulation in Duchenne muscular dystrophy (DMD and combined with advances in respiratory care overall management has improved such that cardiac manifestations have become the major cause of death. Unfortunately, there is no consensus for DMD-associated cardiac disease management. Our purpose was to assess effects of steroid use alone or in combination with angiotensin converting enzyme inhibitors (ACEI or angiotension receptor blocker (ARB on cardiovascular magnetic resonance (CMR derived circumferential strain (εcc. Methods We used CMR to assess effects of corticosteroids alone (Group A or in combination with ACEI or ARB (Group B on heart rate (HR, left ventricular ejection fraction (LVEF, mass (LVM, end diastolic volume (LVEDV and circumferential strain (εcc in a cohort of 171 DMD patients >5 years of age. Treatment decisions were made independently by physicians at both our institution and referral centers and not based on CMR results. Results Patients in Group A (114 studies were younger than those in Group B (92 studies(10 ± 2.4 vs. 12.4 ± 3.2 years, p cc magnitude was lower in Group B than Group A (-13.8 ± 1.9 vs. -12.8 ± 2.0, p = 0.0004, age correction using covariance analysis eliminated this effect. In a subset of patients who underwent serial CMR exams with an inter-study time of ~15 months, εcc worsened regardless of treatment group. Conclusions These results support the need for prospective clinical trials to identify more effective treatment regimens for DMD associated cardiac disease.

  5. Longitudinal strain is a marker of microvascular obstruction and infarct size in patients with acute ST-segment elevation myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Loïc Bière

    Full Text Available OBJECTIVES: We assessed the value of speckle tracking imaging performed early after a first ST-segment elevation myocardial infarction (STEMI in order to predict infarct size and functional recovery at 3-month follow-up. METHODS: 44 patients with STEMI who underwent revascularization within 12 h of symptom onset were prospectively enrolled. Echocardiography was performed 3.9 ± 1.2 days after myocardial reperfusion, assessing circumferential (CGS, radial (RGS, and longitudinal global (GLS strains. Late gadolinium-enhanced cardiac magnetic imaging (CMR, for assessing cardiac function, infarct size, and microvascular obstruction (MVO, was conducted 5.6 ± 2.5 days and 99.4 ± 4.6 days after myocardial reperfusion. RESULTS: GLS was evaluable in 97% of the patients, while CGS and RGS could be assessed in 85%. Infarct size significantly correlated with GLS (R = 0.601, p-6.0% within the infarcted area exhibited 96% specificity and 61% sensitivity for predicting the persistence of akinesia (≥ 3 segments at 3-month follow-up. CONCLUSIONS: Speckle-tracking strain imaging performed early after a STEMI is easy-to-use as a marker for persistent akinetic territories at 3 months. In addition, GLS correlated significantly with MVO and final infarct size, both parameters being relevant post-MI prognostic factors, usually obtained via CMR.

  6. Identifying regional cardiac abnormalities from myocardial strains using nontracking-based strain estimation and spatio-temporal tensor analysis.

    Science.gov (United States)

    Qian, Zhen; Liu, Qingshan; Metaxas, Dimitris N; Axel, Leon

    2011-12-01

    Myocardial strain is a critical indicator of many cardiac diseases and dysfunctions. The goal of this paper is to extract and use the myocardial strain pattern from tagged magnetic resonance imaging (MRI) to identify and localize regional abnormal cardiac function in human subjects. In order to extract the myocardial strains from the tagged images, we developed a novel nontracking-based strain estimation method for tagged MRI. This method is based on the direct extraction of tag deformation, and therefore avoids some limitations of conventional displacement or tracking-based strain estimators. Based on the extracted spatio-temporal strain patterns, we have also developed a novel tensor-based classification framework that better conserves the spatio-temporal structure of the myocardial strain pattern than conventional vector-based classification algorithms. In addition, the tensor-based projection function keeps more of the information of the original feature space, so that abnormal tensors in the subspace can be back-projected to reveal the regional cardiac abnormality in a more physically meaningful way. We have tested our novel methods on 41 human image sequences, and achieved a classification rate of 87.80%. The regional abnormalities recovered from our algorithm agree well with the patient's pathology and clinical image interpretation, and provide a promising avenue for regional cardiac function analysis. PMID:21606022

  7. Quantification of Myocardial Strain at Early Systole in Mouse Heart: Restoration of Undeformed Tagging Grid with Single-Point HARP

    Science.gov (United States)

    Li, Wei; Yu, Xin

    2010-01-01

    Purpose To develop accurate strain and torsion quantification method for the assessment of myocardial contraction in mice by MRI tagging. Materials and Methods Ventricular wall motion at baseline and during β-adrenergic stimulation was assessed in mice using MRI tagging. Myocardial strain and torsion were quantified using finite element analysis method. A harmonic phase (HARP) based method was developed for the restoration of undeformed taglines for more accurate calculation of myocardial wall strain and torsion. Results Myocardial deformation was observed at early systole (taglines that can be used as the reference in finite element analysis of the tagged images. Without such correction for myocardial deformation in the reference image, inaccuracy in strain quantification underestimated significant strain development at early systole in dobutamine-stimulated hearts. Conclusion The HARP-based method developed in the current study enabled automated restoration of undeformed taglines in mouse hearts, leading to more accurate calculation of myocardial wall strain and torsion during dobutamine stimulation. PMID:20815058

  8. Phase-contrast MR imaging evaluation of myocardial motion and strain in dogs

    International Nuclear Information System (INIS)

    This paper reports on the evaluation of an MR imaging technique that would incorporate the benefits of myocardial tagging with enhanced spatial and temporal resolution. A velocity-encoded cine MR imaging technique encoded velocities in two or three dimensions and allowed the tracking of individual segments of the myocardium, as small as 2 mm, throughout the cardiac cycle. In addition, the spatial derivative of velocities provided a noninvasive assessment of myocardial strain. Five dogs with implanted tantulum myocardial tags as a standard were scanned with myocardial-tagged cine MR imaging and this velocity-encoded cine routine. Comparisons were made between the markers studied with cineangiography, myocardial tagging, and velocity-encoded MR imaging

  9. Evaluation of Regional Myocardial Systolic Function in the Early Stage of Acute Myocardial Infarction by Strain Rate Imaging

    Directory of Open Access Journals (Sweden)

    M Esmaeilzadeh

    2009-12-01

    Full Text Available Background: We sought to evaluate the impact of different therapeutic strategies on longitudinal regional myocardial systolic function in the early phase of acute myocardial infarction using strain rate imaging.Methods: A total of 38 patients (34 males, with first acute myocardial infarction (AMI were evaluated. Our patients were divided into 3 groups according to the kind of therapy. The mean age of the patients was 55 ± 9.4 years (range: 39- 75 years. Mean left ventricular ejection fraction (LVEF in the patients was 41 ± 10.7%. Primary percutaneous coronary intervention (PCI was performed in 10 patients. Sixteen patients were treated by thrombolytic therapy using streptokinase (SK and 12 were followed-up conservatively. All patients underwent a comprehensive echocardiography study including SR imaging within 3- 5 days after AMI. The parameters measured included peak systolic strain (peakε and strain rate (SRs, end-systolic strain (εes, post systolic shortening (PSS, time to peak systolic strain rate (tSRs, time to end of shortening (teSRs, post systolic strain (PSε, post-systolic strain index (PSI, PSS ratio (PSS/ εMax and peak postsystolic strain rate (SRPSS. Results: There was not any association either between WMSI and tå (P=0.4, or MI location and PSS ratio (P=0.13. But there was an inverse relationship between WMSI and mean SRS, especially when WMSI was more pronounced. A significant relationship was found between tε and teSRs with the kind of therapy (shorter in PCI group (P= 0.04. Using a simple linear regression model, no association was found between PSS ratio and SRs (â=0.056, P =0.70, PSI and teSRs (β= -0.772, P=0.12. Simple linear regression model showed a weak but significant relationship between PSI and Median tε (β = -0.851, P =0.04; r =0.33.Conclusion: Our study showed that PCI resulted in early recovery of regional systolic function of infarcted myocardium during the early stage of acute myocardial infarction.

  10. Noninvasive monitoring of myocardial function after surgical and cytostatic therapy in a peritoneal metastasis rat model: assessment with tissue Doppler and non-Doppler 2D strain echocardiography

    Directory of Open Access Journals (Sweden)

    Wernecke Klaus-Dieter

    2007-07-01

    Full Text Available Abstract Objective We sought to evaluate the impact of different antineoplastic treatment methods on systolic and diastolic myocardial function, and the feasibility estimation of regional deformation parameters with non-Doppler 2D echocardiography in rats. Background The optimal method for quantitative assessment of global and regional ventricular function in rats and the impact of complex oncological multimodal therapy on left- and right-ventricular function in rats remains unclear. Methods 90 rats after subperitoneal implantation of syngenetic colonic carcinoma cells underwent different onclogical treatment methods and were diveded into one control group and five treatment groups (with 15 rats in each group: group 1 = control group (without operation and without medication, group 2 = operation group without additional therapy, group 3 = combination of operation and photodynamic therapy, group 4 = operation in combination with hyperthermic intraoperative peritoneal chemotherapy with mitomycine, and group 5 = operation in combination with hyperthermic intraoperative peritoneal chemotherapy with gemcitabine, group 6 = operation in combination with taurolidin i.p. instillation. Echocardiographic examination with estimation of wall thickness, diameters, left ventricular fractional shortening, ejection fraction, early and late diastolic transmitral and myocardial velocities, radial and circumferential strain were performed 3–4 days after therapy. Results There was an increase of LVEDD and LVESD in all groups after the follow-up period (P = 0.0037. Other LV dimensions, FS and EF as well as diastolic mitral filling parameters measured by echocardiography were not significantly affected by the different treatments. Values for right ventricular dimensions and function remained unchanged, whereas circumferential 2D strain of the inferior wall was slightly, but significantly reduced under the treatment (-18.1 ± 2.5 before and -16.2 ± 2.9 % after

  11. Assessment of Regional Myocardial Function in Patients with Hypertrophic Cardiomyopathy by Tissue Strain Imaging

    Institute of Scientific and Technical Information of China (English)

    XIONG Runqing; XIE Mingxing; WANG Xinfang; L(U) Qing

    2006-01-01

    The value of tissue strain imaging (SI) in regional myocardial systolic anddiastolic function assessment was studied. In 18 patients with nonobstructive hypertrophic cardiomyopathy (HCM) and 20 age-matched healthy subjects, regional myocardial longitudinal peak systolic strain in eject time (represented by εet) was measured at basal, mid and apical segments of septal, lateral and posterior walls of the left ventricle (LV) and compared between groups. εet had no significant difference between segments in control group (P>0.05), which displayed a decreasing trend from basal segments to apical ones. εet in the HCM group was significantly decreased (P<0. 05) as compared with that in the healthy group. In the HCM group, εet in the midseptum was significantly less than at the basal and apical septum, and was also less than at the rest LV walls in the same group (P<0.01). The systolic reversed εet was noticed in 35 % of the hypertrophic segments in HCM group. Significantly negative correlation existed between the absolute value of εet and wall thickness in the midseptum (r=- 0.83). The post-systolic strain(PSS) segment number the and amplitudes in healthy group were significantly less than those in HCM group (P<0.05). Both regional myocardial systolic and diastolic functions were impaired in hypertrophic or non-hypertrophic segments in patients with the HCM, especially in hypertrophic segments. Strain imaging technique is a sensitive and accura tool in myocardial dysfunction assessment.

  12. Longitudinal Strain Is a Marker of Microvascular Obstruction and Infarct Size in Patients with Acute ST-Segment Elevation Myocardial Infarction

    OpenAIRE

    Loïc Bière; Erwan Donal; Gwenola Terrien; Gaëlle Kervio; Serge Willoteaux; Alain Furber; Fabrice Prunier

    2014-01-01

    International audience Objectives: We assessed the value of speckle tracking imaging performed early after a first ST-segment elevation myocardial infarction (STEMI) in order to predict infarct size and functional recovery at 3-month follow-up. Methods: 44 patients with STEMI who underwent revascularization within 12 h of symptom onset were prospectively enrolled. Echocardiography was performed 3.961.2 days after myocardial reperfusion, assessing circumferential (CGS), radial (RGS), and lo...

  13. Significant association of cagA positive Helicobacter pylori strains with risk of premature myocardial infarction

    OpenAIRE

    Gunn, M.; Stephens, J.; Thompson, J.; Rathbone, B; Samani, N

    2000-01-01

    OBJECTIVE—To investigate whether genetic diversity of Helicobacter pylori influences its association with coronary heart disease, and specifically whether the risk is confined to infection with the more virulent strains bearing the cytotoxin associated gene-A (cagA) antigen.
DESIGN AND SETTING—Case-control study in hospital admitting unselected patients with myocardial infarction.
METHODS AND SUBJECTS—Serological status for cagA and H pylori were determined in 342 cases of acute myocardial in...

  14. Early diastolic strain rate in relation to systolic and diastolic function and prognosis in acute myocardial infarction

    DEFF Research Database (Denmark)

    Ersbøll, Mads; Andersen, Mads J; Valeur, Nana; Mogensen, Ulrik M; Fahkri, Yama; Thune, Jens J; Møller, Jacob E; Hassager, Christian; Søgaard, Peter; Køber, Lars

    2014-01-01

    AIMS: Diastolic dysfunction in acute myocardial infarction (MI) is associated with adverse outcome. Recently, the ratio of early mitral inflow velocity (E) to global diastolic strain rate (e'sr) has been proposed as a marker of elevated LV filling pressure. However, the prognostic value of this.......0001). CONCLUSION: Deformation-based E/e'sr contributes important information about global myocardial relaxation superior to velocity-based analysis and is independently associated with the outcome in acute MI....

  15. Doppler-derived myocardial systolic strain rate is a strong index of left ventricular contractility

    Science.gov (United States)

    Greenberg, Neil L.; Firstenberg, Michael S.; Castro, Peter L.; Main, Michael; Travaglini, Agnese; Odabashian, Jill A.; Drinko, Jeanne K.; Rodriguez, L. Leonardo; Thomas, James D.; Garcia, Mario J.

    2002-01-01

    BACKGROUND: Myocardial fiber strain is directly related to left ventricular (LV) contractility. Strain rate can be estimated as the spatial derivative of velocities (dV/ds) obtained by tissue Doppler echocardiography (TDE). The purposes of the study were (1) to determine whether TDE-derived strain rate may be used as a noninvasive, quantitative index of contractility and (2) to compare the relative accuracy of systolic strain rate against TDE velocities alone. METHODS AND RESULTS: TDE color M-mode images of the interventricular septum were recorded from the apical 4-chamber view in 7 closed-chest anesthetized mongrel dogs during 5 different inotropic stages. Simultaneous LV volume and pressure were obtained with a combined conductance-high-fidelity pressure catheter. Peak elastance (Emax) was determined as the slope of end-systolic pressure-volume relationships during caval occlusion and was used as the gold standard of LV contractility. Peak systolic TDE myocardial velocities (Sm) and peak (epsilon'(p)) and mean (epsilon'(m)) strain rates obtained at the basal septum were compared against Emax by linear regression. Emax as well as TDE systolic indices increased during inotropic stimulation with dobutamine and decreased with the infusion of esmolol. A stronger association was found between Emax and epsilon'(p) (r=0.94, P<0.01, y=0.29x+0.46) and epsilon'(m) (r=0.88, P<0.01) than for Sm (r=0.75, P<0.01). CONCLUSIONS: TDE-derived epsilon'(p) and epsilon'(m) are strong noninvasive indices of LV contractility. These indices appear to be more reliable than S(m), perhaps by eliminating translational artifact.

  16. Myocardial dysfunction in patients with chronic kidney disease evaluated by global 2-dimensional strain imaging%二维超声应变评价慢性肾病心肌损害的价值

    Institute of Scientific and Technical Information of China (English)

    王泓; 曹铁生; 杨斌; 傅宁华; 李娟; 孙晖

    2011-01-01

    Objective To evaluate whether global 2-dimensional strain imaging can offer additional benefit over conventional echocardiography to detect subclinical myocardial damage in patients with chronic kidney disease(CKD). Methods Conventional echocardiography and global 2-dimension strain imaging were performed in 39 patients with CKD [23 men and 16 women,mean age (45.6± 14.6) years] and 29 control subjects. Twenty patients had CKD stage 2 or 3(group 1 ) and nineteen patients had CKD stage 4 or 5(group 2). Left ventricular structure and function were evaluated by conventional echocardiography. Global longitudinal and circumferential strain and strain rate were analyzed. Results There were no differences in ejection fraction and fraction shortening between CKD patients and controls. Compared with controls, CKD groups had significantly decreased value of global longitudinal strain and strain rate. Global longitudinal strain decreased from - (23.8 ± 3.1 ) % in controls to - ( 18. 5 ± 2.4) % in group 1 and to - (15.2 ± 3.2) % in group 2 ( P <0. 001 ). Compared with controls, there was no difference in global circumferential strain and strain rate between group 1 and controls, but global circumferential strain and strain rate of group 2 was reduced [ - (17.1± 3. 0) % vs -(21.2±2.8)%, P<0.05;-(1.0±0.2)% vs -(1.3±0.3)%, P<0.05]. In correlation analyses, global longitudinal strain was positively related to eGFR( r =0. 376, P <0. 001 ) and inversely related to left ventricular mass index( r = - 0. 473, P <0.01). Conclusions Global 2-dimensional strain imaging may represent a useful tool for the assessment of subclinical myocardial dysfunction in patients with CKD.%目的 探讨整体二维超声应变成像评价慢性肾病(CKD)心肌损害的价值.方法 39例CKD患者,其中20例为2~3期CKD患者(组1),19例为4~5期CKD患者(组2),设29例正常对照.使用常规超声心动图评价左室结构和功能,使用二维超声应变成像评价心肌整

  17. Infection by Helicobacter pylori and acute myocardial infarction. Do cytotoxic strains make a difference?

    Science.gov (United States)

    Pellicano, R; Parravicini, P P; Bigi, R; Gandolfo, N; Aruta, E; Gai, V; Figura, N; Angelino, P; Rizzetto, M; Ponzetto, A

    2002-07-01

    The classical risk factors for acute myocardial infarction (AMI) fail to explain all the epidemiological variations of the disease. Among the risk factors recently reported, several infectious agents appear to increase the risk of AMI. Helicobacter pylori (H. pylori) infection, a bacterium involved in duodenal and gastric ulcer, gastric cancer and MALT-lymphoma, seems to be strongly associated with AMI. More virulent (anti-CagA positive) strains of the bacterium are almost exclusively the causative agents of such diseases. To determine the prevalence of H. pylori infection and of virulent strains, a case-control study was conducted in a group of male patients with AMI. A group of patients consecutively admitted to the Emergency Care Unit served as controls. We studied 223 consecutive male patients, mean age 60.2 (range 40-79) years, admitted for AMI to the Coronary Care Units at Hospitals in two towns of Northern Italy, 223 age matched male patients (mean age 61.8, range 40-79 years) admitted to the Emergency Care Unit, served as control. H. pylori seroprevalence was assessed by presence of antibodies (IgG) against H. pylori and anti-CagA in circulation. Among the patients we investigated the presence of hypertension, levels of cholesterol and glucose in serum, fibrinogen in plasma and smoking habits. H. pylori infection was present in 189/223 (84.7%) of the patients and in 138/223 (61.8%) of the control population (p myocardial infarction had a notably higher prevalence of anti-H. pylori not restricted to virulent strains, when compared to a population of patients referred to the Emergency Care Unit. The classical risk factors for coronary disease were present in the patients with AMI irrespective of H. pylori status. PMID:12173773

  18. Acrolein inhalation causes myocardial strain delay and decreased cardiac performance as detected by high-frequency echocardiography in mice

    Science.gov (United States)

    Acrolein, an unsaturated aldehyde found in air pollution, impairs Ca2+ flux and contraction in cardiomyocytes in vitro. To better define direct and delayed functional cardiac effects, we hypothesized that a single exposure to acrolein would modify myocardial strain and performanc...

  19. A novel, view-independent method for strain mapping in myocardial elastography: eliminating angle and centroid dependence

    International Nuclear Information System (INIS)

    Robust indices of regional and global cardiac function are a key factor in detection and treatment of heart disease as well as understanding of the fundamental mechanisms of a healthy heart. Myocardial elastography provides a noninvasive method for imaging and measuring displacement and strain of the myocardium for the early detection of cardiovascular disease. However, two-dimensional in-plane axial and lateral strains measured depend on the sonographic view used. This becomes especially critical in a clinical setting and may induce large variations in the measured strains, potentially leading to false diagnoses. A novel method in myocardial elastography is proposed for eliminating this view dependence by deriving the polar, principal and classified principal strains. The performance of the proposed methodology is assessed by employing 3D finite-element left-ventricular models of a control and an ischemic canine heart. Although polar strains are angle-independent, they are sensitive to the selected reference coordinate system, which requires the definition of a centroid of the left ventricle (LV). In contrast, principal strains derived through eigenvalue decomposition exhibit the inherent characteristic of coordinate system independence, offering view (i.e., angle and centroid)-independent strain measurements. Classified principal strains are obtained by assigning the principal components in the physical ventricular coordinate system. An extensive strain analysis illustrates the improvement in interpretation and visualization of the full-field myocardial deformation by using the classified principal strains, clearly depicting the ischemic and non-ischemic regions. Strain maps, independent of sonographic views and imaging planes, that can be used to accurately detect regional contractile dysfunction are demonstrated

  20. Left ventricular strain and its pattern estimated from cine CMR and validation with DENSE

    Science.gov (United States)

    Gao, Hao; Allan, Andrew; McComb, Christie; Luo, Xiaoyu; Berry, Colin

    2014-07-01

    Measurement of local strain provides insight into the biomechanical significance of viable myocardium. We attempted to estimate myocardial strain from cine cardiovascular magnetic resonance (CMR) images by using a b-spline deformable image registration method. Three healthy volunteers and 41 patients with either recent or chronic myocardial infarction (MI) were studied at 1.5 Tesla with both cine and DENSE CMR. Regional circumferential and radial left ventricular strains were estimated from cine and DENSE acquisitions. In all healthy volunteers, there was no difference for peak circumferential strain (- 0.18 ± 0.04 versus - 0.18 ± 0.03, p = 0.76) between cine and DENSE CMR, however peak radial strain was overestimated from cine (0.84 ± 0.37 versus 0.49 ± 0.2, p < 0.01). In the patient study, the peak strain patterns predicted by cine were similar to the patterns from DENSE, including the strain evolution related to recovery time and strain patterns related to MI scar extent. Furthermore, cine-derived strain disclosed different strain patterns in MI and non-MI regions, and regions with transmural and non-transmural MI as DENSE. Although there were large variations with radial strain measurements from cine CMR images, useful circumferential strain information can be obtained from routine clinical CMR imaging. Cine strain analysis has potential to improve the diagnostic yield from routine CMR imaging in clinical practice.

  1. Early Detection of Regional and Global Left Ventricular Myocardial Function Using Strain and Strain-rate Imaging in Patients with Metabolic Syndrome

    Institute of Scientific and Technical Information of China (English)

    Qin Wang; Qi-Wei Sun; Dan Wu; Ming-Wu Yang; Rong-Juan Li; Bo Jiang; Jiao Yang

    2015-01-01

    Background:Strain and strain-rate imaging (SRI) have been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies,and identifying early subclinical changes in various pathologies.The aim of this study was to evaluate the regional and global left ventricular (LV) myocardial function in metabolic syndrome (MS) with SRI so that we can provide more myocardial small lesions in patients with MS,which is robust and reliable basis for early detection of LV function.Methods:Thirty-nine adults with MS were enrolled in the study.There was a control group of 39 healthy adults.In addition to classic echocardiographic assessment of LV global functional changes,SRI was used to evaluate regional and global LV function.Including:Peak systolic strain (S),peak systolic strain-rate (SR-s),peak diastolic strain-rate (SR-e).Results:There were no statistically significant differences between MS and controls in all traditional parameters of LV systolic function.On the other hand,significant differences were observed between MS and the control group in most of the parameters of S,SR-s,SR-e in regional LV function.Multiple stepwise regression analyses revealed that S and SR significantly were negatively correlated with blood pressure,waist circumference,fasting plasma glucose,uric acid,suggesting that risk factories were relevant to regional systolic dysfunction.Conclusion:In MS with normal LV ejection fraction,there was regional myocardial dysfunction,risk factors contributed to the impairment of systolic and diastolic function of the regional myocardium.Assessment of myocardial function using SRI could be more accurate in MS patient evaluation than conventional echocardiography alone.

  2. Prediction of all-cause mortality and heart failure admissions from global left ventricular longitudinal strain in patients with acute myocardial infarction and preserved left ventricular ejection fraction

    DEFF Research Database (Denmark)

    Ersbøll, Mads; Valeur, Nana; Mogensen, Ulrik Madvig;

    2013-01-01

    This study sought to test the hypothesis that semiautomated calculation of left ventricular global longitudinal strain (GLS) can identify high-risk subjects among patients with myocardial infarctions (MIs) with left ventricular ejection fractions (LVEFs) >40%.......This study sought to test the hypothesis that semiautomated calculation of left ventricular global longitudinal strain (GLS) can identify high-risk subjects among patients with myocardial infarctions (MIs) with left ventricular ejection fractions (LVEFs) >40%....

  3. Total Removal of Unwanted Harmonic Peaks (TruHARP) MRI for Single Breath-Hold High-Resolution Myocardial Motion and Strain Quantification

    OpenAIRE

    Agarwal, Harsh K.; Prince, Jerry L.; Abd-Elmoniem, Khaled Z.

    2010-01-01

    Current MRI methods for myocardial motion and strain quantification have limited resolution because of Fourier space spectral peak interference. Methods have been proposed to remove this interference in order to improve resolution; however, these methods are clinically impractical due to the prolonged imaging times. In this paper, we propose total removal of unwanted harmonic peaks (TruHARP); a myocardial motion and strain quantification methodology that uses a novel single breath-hold MR ima...

  4. Myocardial Strain Analysis by 2-Dimensional Speckle Tracking Echocardiography Improves Diagnostics of Coronary Artery Stenosis in Stable Angina Pectoris

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Hoffmann, Soren; Mogelvang, Rasmus;

    2014-01-01

    BACKGROUND: Two-dimensional strain echocardiography detects early signs of left ventricular dysfunction; however, it is unknown whether myocardial strain analysis at rest in patients with suspected stable angina pectoris predicts the presence of coronary artery disease (CAD). METHODS AND RESULTS......<0.001) and remained an independent predictor of CAD after multivariable adjustment for baseline data, exercise test, and conventional echocardiography (odds ratio, 1.25 [P=0.016] per 1% decrease). Area under receiver operating characteristic curve for exercise test and global longitudinal peak...

  5. In vivo study of myocardial elastography under graded ischemia conditions

    International Nuclear Information System (INIS)

    The capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction

  6. In vivo study of myocardial elastography under graded ischemia conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wei-Ning; Provost, Jean; Konofagou, Elisa E [Department of Biomedical Engineering, Columbia University, New York, NY (United States); Fujikura, Kana [Department of Radiology, Columbia University, New York, NY (United States); Wang Jie, E-mail: ek2191@columbia.edu [Department of Medicine, Columbia University, New York, NY (United States)

    2011-02-21

    The capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction

  7. Evaluation of Global and Regional Strain in Patients with Acute Coronary Syndrome without Previous Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Alireza Moaref

    2016-03-01

    Full Text Available Speckle Tracking Echocardiography (STE is a new non-invasive method, which has been recently used as an alternative technique to assess regional and global myocardial function, especially left ventricular function. It is also considered to be a valid technique to evaluate the patients with Acute Coronary Syndrome (ACS.

  8. Electro-mechanical characteristics of myocardial infarction border zones and ventricular arrhythmic risk: novel insights from grid-tagged cardiac magnetic resonance imaging

    International Nuclear Information System (INIS)

    To investigate whether grid-tag myocardial strain evaluation can characterise 'border-zone' peri-infarct region and identify patients at risk of ventricular arrhythmia as the peri-infarct myocardial zone may represent an important contributor to ventricular arrhythmia following ST-segment elevation myocardial infarction (STEMI). Forty-five patients with STEMI underwent cardiac magnetic resonance (CMR) imaging on days 3 and 90 following primary percutaneous coronary intervention (PCI). Circumferential peak circumferential systolic strain (CS) and strain rate (CSR) were calculated from grid-tagged images. Myocardial segments were classified into 'infarct', 'border-zone', 'adjacent' and 'remote' regions by late-gadolinium enhancement distribution. The relationship between CS and CSR and these distinct myocardial regions was assessed. Ambulatory Holter monitoring was performed 14 days post myocardial infarction (MI) to estimate ventricular arrhythmia risk via evaluation of heart-rate variability (HRV). We analysed 1,222 myocardial segments. Remote and adjacent regions had near-normal parameters of CS and CSR. Border-zone regions had intermediate CS (-9.0 ± 4.6 vs -5.9 ± 7.4, P < 0.001) and CSR (-86.4 ± 33.3 vs -73.5 ± 51.4, P < 0.001) severity compared with infarct regions. Patients with 'border-zone' peri-infarct regions had reduced very-low-frequency power on HRV analysis, which is a surrogate for ventricular arrhythmia risk (P = 0.03). Grid-tagged CMR-derived myocardial strain accurately characterises the mechanical characteristics of 'border-zone' peri-infarct region. Presence of 'border-zone' peri-infarct region correlated with a surrogate marker of heightened arrhythmia risk following STEMI. (orig.)

  9. Electro-mechanical characteristics of myocardial infarction border zones and ventricular arrhythmic risk: novel insights from grid-tagged cardiac magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Dennis T.L.; Weightman, Michael J.; Baumert, Mathias; Tayeb, Hussam; Richardson, James D.; Puri, Rishi; Bertaso, Angela G.; Roberts-Thomson, Kurt C.; Sanders, Prashanthan; Worthley, Matthew I. [University of Adelaide, Cardiovascular Research Centre, Royal Adelaide Hospital and Discipline of Medicine, SA (Australia); Worthley, Stephen G. [University of Adelaide, Cardiovascular Research Centre, Royal Adelaide Hospital and Discipline of Medicine, SA (Australia); Royal Adelaide Hospital, Cardiovascular Investigational Unit, SA (Australia)

    2012-08-15

    To investigate whether grid-tag myocardial strain evaluation can characterise 'border-zone' peri-infarct region and identify patients at risk of ventricular arrhythmia as the peri-infarct myocardial zone may represent an important contributor to ventricular arrhythmia following ST-segment elevation myocardial infarction (STEMI). Forty-five patients with STEMI underwent cardiac magnetic resonance (CMR) imaging on days 3 and 90 following primary percutaneous coronary intervention (PCI). Circumferential peak circumferential systolic strain (CS) and strain rate (CSR) were calculated from grid-tagged images. Myocardial segments were classified into 'infarct', 'border-zone', 'adjacent' and 'remote' regions by late-gadolinium enhancement distribution. The relationship between CS and CSR and these distinct myocardial regions was assessed. Ambulatory Holter monitoring was performed 14 days post myocardial infarction (MI) to estimate ventricular arrhythmia risk via evaluation of heart-rate variability (HRV). We analysed 1,222 myocardial segments. Remote and adjacent regions had near-normal parameters of CS and CSR. Border-zone regions had intermediate CS (-9.0 {+-} 4.6 vs -5.9 {+-} 7.4, P < 0.001) and CSR (-86.4 {+-} 33.3 vs -73.5 {+-} 51.4, P < 0.001) severity compared with infarct regions. Patients with 'border-zone' peri-infarct regions had reduced very-low-frequency power on HRV analysis, which is a surrogate for ventricular arrhythmia risk (P = 0.03). Grid-tagged CMR-derived myocardial strain accurately characterises the mechanical characteristics of 'border-zone' peri-infarct region. Presence of 'border-zone' peri-infarct region correlated with a surrogate marker of heightened arrhythmia risk following STEMI. (orig.)

  10. Quantitative analysis of left ventricular strain using cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Buss, Sebastian J., E-mail: sebastian.buss@med.uni-heidelberg.de [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Schulz, Felix; Mereles, Derliz [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Hosch, Waldemar [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Galuschky, Christian; Schummers, Georg; Stapf, Daniel [TomTec Imaging Systems GmbH, Munich (Germany); Hofmann, Nina; Giannitsis, Evangelos; Hardt, Stefan E. [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Katus, Hugo A.; Korosoglou, Grigorios [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany)

    2014-03-15

    Objectives: To investigate whether cardiac computed tomography (CCT) can determine left ventricular (LV) radial, circumferential and longitudinal myocardial deformation in comparison to two-dimensional echocardiography in patients with congestive heart failure. Background: Echocardiography allows for accurate assessment of strain with high temporal resolution. A reduced strain is associated with a poor prognosis in cardiomyopathies. However, strain imaging is limited in patients with poor echogenic windows, so that, in selected cases, tomographic imaging techniques may be preferable for the evaluation of myocardial deformation. Methods: Consecutive patients (n = 27) with congestive heart failure who underwent a clinically indicated ECG-gated contrast-enhanced 64-slice dual-source CCT for the evaluation of the cardiac veins prior to cardiac resynchronization therapy (CRT) were included. All patients underwent additional echocardiography. LV radial, circumferential and longitudinal strain and strain rates were analyzed in identical midventricular short axis, 4-, 2- and 3-chamber views for both modalities using the same prototype software algorithm (feature tracking). Time for analysis was assessed for both modalities. Results: Close correlations were observed for both techniques regarding global strain (r = 0.93, r = 0.87 and r = 0.84 for radial, circumferential and longitudinal strain, respectively, p < 0.001 for all). Similar trends were observed for regional radial, longitudinal and circumferential strain (r = 0.88, r = 0.84 and r = 0.94, respectively, p < 0.001 for all). The number of non-diagnostic myocardial segments was significantly higher with echocardiography than with CCT (9.6% versus 1.9%, p < 0.001). In addition, the required time for complete quantitative strain analysis was significantly shorter for CCT compared to echocardiography (877 ± 119 s per patient versus 1105 ± 258 s per patient, p < 0.001). Conclusion: Quantitative assessment of LV strain

  11. Experimental assessment of a new research tool for the estimation of two-dimensional myocardial strain.

    Science.gov (United States)

    Langeland, Stian; Wouters, Patrick F; Claus, Piet; Leather, H Alex; Bijnens, Bart; Sutherland, George R; Rademakers, Frank E; D'hooge, Jan

    2006-10-01

    One-dimensional strain imaging has been shown to be angle dependent. To address this problem, a new methodology, 2D-strain, has become available. The aim of this study was to validate this methodology in an in vivo set-up against sonomicrometry. In five open chest sheep, ultrasound gray-scale images were acquired of the inferolateral wall from two different angles. The longitudinal and radial strain components were simultaneously extracted using the novel 2D-strain methodology. The extracted values were compared with sonomicrometry using Bland-Altman statistics and correlation coefficients. A good agreement was found for the longitudinal strain component, while, for the radial strain estimates, the accuracy was less. 2D-strain is a fast and accurate tool to assess longitudinal strain from apical views. Further improvements are needed for the method to be sufficiently accurate in estimating the deformation perpendicular or close to perpendicular to the ultrasound beam. PMID:17045871

  12. Strain and strain rate by two-dimensional speckle tracking echocardiography in a maned wolf

    Directory of Open Access Journals (Sweden)

    Matheus M. Mantovani

    2012-12-01

    Full Text Available The measurement of cardiovascular features of wild animals is important, as is the measurement in pets, for the assessment of myocardial function and the early detection of cardiac abnormalities, which could progress to heart failure. Speckle tracking echocardiography (2D STE is a new tool that has been used in veterinary medicine, which demonstrates several advantages, such as angle independence and the possibility to provide the early diagnosis of myocardial alterations. The aim of this study was to evaluate the left myocardial function in a maned wolf by 2D STE. Thus, the longitudinal, circumferential and radial strain and strain rate were obtained, as well as, the radial and longitudinal velocity and displacement values, from the right parasternal long axis four-chamber view, the left parasternal apical four chamber view and the parasternal short axis at the level of the papillary muscles. The results of the longitudinal variables were -13.52±7.88, -1.60±1.05, 4.34±2.52 and 3.86±3.04 for strain (%, strain rate (1/s, displacement (mm and velocity (cm/s, respectively. In addition, the radial and circumferential Strain and Strain rate were 24.39±14.23, 1.86±0.95 and -13.69±6.53, -1.01±0.48, respectively. Thus, the present study provides the first data regarding the use of this tool in maned wolves, allowing a more complete quantification of myocardial function in this species.

  13. Influence of Positive End-Expiratory Pressure on Myocardial Strain Assessed by Speckle Tracking Echocardiography in Mechanically Ventilated Patients

    Directory of Open Access Journals (Sweden)

    Federico Franchi

    2013-01-01

    Full Text Available Purpose. The effects of mechanical ventilation (MV on speckle tracking echocardiography- (STE-derived variables are not elucidated. The aim of the study was to evaluate the effects of positive end-expiratory pressure (PEEP ventilation on 4-chamber longitudinal strain (LS analysis by STE. Methods. We studied 20 patients admitted to a mixed intensive care unit who required intubation for MV and PEEP titration due to hypoxia. STE was performed at three times: (T1 PEEP = 5 cmH2O; (T2 PEEP = 10 cmH2O; and (T3 PEEP = 15 cmH2O. STE analysis was performed offline using a dedicated software (XStrain MyLab 70 Xvision, Esaote. Results. Left peak atrial-longitudinal strain (LS was significantly reduced from T1 to T2 and from T2 to T3 (. Right peak atrial-LS and right ventricular-LS showed a significant reduction only at T3 (. Left ventricular-LS did not change significantly during titration of PEEP. Cardiac chambers’ volumes showed a significant reduction at higher levels of PEEP (. Conclusions. We demonstrated for the first time that incremental PEEP affects myocardial strain values obtained with STE in intubated critically ill patients. Whenever performing STE in mechanically ventilated patients, care must be taken when PEEP is higher than 10 cmH2O to avoid misinterpreting data and making erroneous decisions.

  14. Myocardial Integrated Backscatter in Obese Adolescents: Associations with Measures of Adiposity and Left Ventricular Deformation.

    Directory of Open Access Journals (Sweden)

    Lijian Xie

    Full Text Available Myocardial fibrosis has been proposed to play an important pathogenetic role in left ventricular (LV dysfunction in obesity. This study tested the hypothesis that calibrated integrated backscatter (cIB as a marker of myocardial fibrosis is altered in obese adolescents and explored its associations with adiposity, LV myocardial deformation, and metabolic parameters.Fifty-two obese adolescents and 38 non-obese controls were studied with conventional and speckle tracking echocardiography. The average cIB of ventricular septum and LV posterior wall was measured. In obese subjects, insulin resistance as estimated by homeostasis model assessment (HOMA-IR and glucose tolerance were determined. Compared with controls, obese subjects had significantly greater cIB of ventricular septum (-16.8±7.8 dB vs -23.2±7.8 dB, p<0.001, LV posterior wall (-20.5±5.6 dBvs -25.0±5.1 dB, p<0.001 and their average (-18.7±5.7 dB vs -24.1±5.0 dB, p<0.001. For myocardial deformation, obese subjects had significantly reduced LV longitudinal systolic strain rate (SR (p = 0.045 and early diastolic SR (p = 0.015, and LV circumferential systolic strain (p = 0.008, but greater LV longitudinal late diastolic SR (p<0.001, and radial early (p = 0.037 and late (p = 0.002 diastolic SR than controls. For the entire cohort, myocardial cIB correlated positively with body mass index (r = 0.45, p<0.001 and waist circumference (r = 0.45, p<0.001, but negatively with LV circumferential systolic strain (r = -0.23, p = 0.03 and systolic SR (r = -0.25, p = 0.016. Among obese subjects, cIB tended to correlate with HOMA-IR (r = 0.26, p = 0.07.Obese adolescents already exhibit evidence of increased myocardial fibrosis, which is associated with measures of adiposity and impaired LV circumferential myocardial deformation.

  15. The influence of real-time blood glucose levels on left ventricular myocardial strain and strain rate in pediatric patients with type 1 diabetes mellitus - a speckle tracking echocardiography study

    OpenAIRE

    Hensel, Kai O.; Grimmer, Franziska; Jenke, Andreas C.; Wirth, Stefan; Heusch, Andreas

    2015-01-01

    Background Echocardiographic myocardial performance parameters such as strain and strain rate are increasingly used to assess systolic and diastolic function in patients with diabetes mellitus and several other clinical and scientific scenarios. While long-term metabolic marks such as HbA1C are inherently assessed in diabetic patients, the actual blood glucose level at the very moment of the echocardiographic study has not yet been taken into account for the assessment of cardiac mechanics. T...

  16. Two-dimensional strain and twist by vector velocity imaging in adolescents with severe obesity.

    Science.gov (United States)

    Obert, Philippe; Gueugnon, Carine; Nottin, Stéphane; Vinet, Agnes; Gayrard, Sandrine; Rupp, Thomas; Dumoulin, Gilles; Tordi, Nicolas; Mougin, Fabienne

    2012-12-01

    The prevalence of severe obesity is increasing worldwide in adolescents. Whether it is associated with functional myocardial abnormalities remains largely unknown, potentially because of its frequent association with other cardiovascular risk factors and also use of insensitive techniques to detect subclinical changes in myocardial function. We used 2D vector velocity imaging (VVI) to investigate early changes in left ventricular (LV) myocardial function in youths with isolated severe obesity. Thirty-seven asymptomatic severely obese adolescents free of diabetes and hypertension, and 24 lean controls were enrolled. LV longitudinal, basal, and apical circumferential strain, strain rate (SR), rotations, and LV twist were measured. Obese adolescents had greater LV mass and reduced systolic and early diastolic tissue Doppler imaging (TDI) velocities than lean counterparts. L strain (-24%) and systolic and early diastolic SR were also diminished in the obese, whereas no intergroup differences existed for the circumferential deformation indexes. LV twist was more pronounced in the obese (+1.7°, P twist/untwist along the cardiac cycle was preserved with severe obesity. Isolated severe obesity in adolescents, at a preclinical stage, is associated with changes in myocardial deformation and torsional mechanics that could be in part related to alterations in relaxation and contractility properties of subendocardial fibers. PMID:22653310

  17. Left ventricular myocardial function in hemodialysis and nondialysis uremia patients: a three-dimensional speckle-tracking echocardiography study.

    Directory of Open Access Journals (Sweden)

    Ran Chen

    Full Text Available BACKGROUND: Several studies have demonstrated that uremic patients who have preserved left ventricular ejection fraction (LVEF could still have the potential for systolic dysfunction. The aim of this study was to assess the differences between the left ventricular (LV myocardial function in hemodialysis and nondialysis uremic patients based on three-dimensional speckle-tracking echocardiography. METHODS: The study population consisted of 35 maintenance hemodialysis patients (the hemodialysis group, 30 uremic patients who were hospitalized for the creation of a primary arteriovenous fistula (the nondialysis group, and 32 healthy volunteers. All of the patients had normal left ventricular ejection fractions (i.e., 55% or greater. Three-dimensional speckle tracking echocardiography was performed to assess the left ventricle's global three-dimensional strain, regional longitudinal strain, circumferential strain, and radial strain. RESULTS: The left ventricular regional longitudinal strain, radial strain, circumferential strain, and global three-dimensional strain were significantly decreased in the nondialysis patients compared with the other two groups (all, P<0.001. However, the three-dimensional strain and the regional longitudinal strain were lower in the hemodialysis patients than in the controls (P<0.01. In the hemodialysis patients and the control group, the longitudinal strain, circumferential strain, and radial strain were higher at the apical level than they were at the basal level and midlevels. A multivariate linear regression analysis showed that the blood urea nitrogen and creatinine levels were independently associated with the values of the global three-dimensional strain (β = -0.217, P = 0.000; β = -0.243, P = 0.011, respectively and the longitudinal strain (β = -0.154, P = 0.032; β = -0.188, P = 0.029, respectively. CONCLUSIONS: Three-dimensional speckle-tracking echocardiography may detect

  18. Circumferential profiles for region-based analysis of dynamic SPECT data

    International Nuclear Information System (INIS)

    Kinetic parameters (washin, washout) of dynamic SPECT teboroxime data sets may provide a more sensitive measure of coronary artery disease than conventional (Tl, MIBI) static myocardial perfusion studies. A time-consuming and subjective step of the data analysis is drawing regions of interest to delineate blood pool and myocardial tissue regions. The time-activity curves for the regions are then used to estimate local kinetic parameters. In this work, the appropriate time-activity curves are found automatically, in a manner similar to that used for calculating circumferential profiles in conventional static cardiac studies. The drawbacks to applying standard static circumferential profile methods are the high noise level and high liver uptake common in dynamic studies. Searching along each ray for maxima to locate the myocardium does not always provide useful information. Here we propose an iterative scheme in which constraints are imposed on the radii searched. The constraints are based on the shape of the time-activity curve of the circumferential profile members and on an assumption that the short axis slices are approximately circular. The constraints eliminate outliers and help to reduce the effects of the noise and the liver activity. Kinetic parameter estimates from the automatically generated regions were comparable to estimates from manually selected regions in canine dynamic teboroxime studies

  19. Is the effect of job strain on myocardial infarction risk due to interaction between high psychological demands and low decision latitude?

    DEFF Research Database (Denmark)

    Hallqvist, J; Diderichsen, Finn; Theorell, T;

    1998-01-01

    population-based case-referent study having incident first events of myocardial infarction as outcome (SHEEP: Stockholm Heart Epidemiology Program). The analysis is restricted to males 45-64 yr of age with a more detailed analysis confined to those still working at inclusion. In total, 1047 cases and 1450...... referents were included in the analysis. Exposure categories of job strain were formed from self reported questionnaire information. The results show that high demands and low decision latitude interact with a synergy index of 7.5 (95% C.I.: 1.8-30.6) providing empirical support for the core mechanism of...... the job strain model. Manual workers are more susceptible when exposed to job strain and its components and this increased susceptibility explains about 25-50% of the relative excess risk among manual workers. Low decision latitude may also, as a causal link, explain about 30% of the socioeconomic...

  20. 49 CFR 178.345-7 - Circumferential reinforcements.

    Science.gov (United States)

    2010-10-01

    ... circumferential reinforcement member, whether internal or external, reinforcement must be continuous around the... tank heads. (1) Circumferential reinforcement must be located so that the thickness and tensile strength of the shell material in combination with the frame and reinforcement produces...

  1. Circumferential cracking of steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Karwoski, K.J.

    1997-04-01

    On April 28, 1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 95-03, {open_quote}Circumferential Cracking of Steam Generator Tubes.{close_quote} GL 95-03 was issued to obtain information needed to verify licensee compliance with existing regulatory requirements regarding the integrity of steam generator tubes in domestic pressurized-water reactors (PWRs). This report briefly describes the design and function of domestic steam generators and summarizes the staff`s assessment of the responses to GL 95-03. The report concludes with several observations related to steam generator operating experience. This report is intended to be representative of significant operating experience pertaining to circumferential cracking of steam generator tubes from April 1995 through December 1996. Operating experience prior to April 1995 is discussed throughout the report, as necessary, for completeness.

  2. Circumferential TIG welding of zircaloy flow tubes

    International Nuclear Information System (INIS)

    Reactivity control mechanism consists of 10 mtr. long zircaloy flow tubes (inner and outer) with components welded to hold the absorber elements. These components were welded by the plug welding process and supplied to Madras Atomic Power Station (MAPS) and Narora Atomic Power Station (NAPS). In view of the in-service problem faced in Rajasthan Atomic Power Station (RAPS), the spot welds were modified to circumferential TIG welding with additional reinforcement. Development work was taken up for additional reinforcement with screws and circumferential TIG welding of these assemblies. The additional reinforcement with screws and spot welds were critically examined and the job was taken up and successfully completed at Narora site for Narora Atomic Power Projects (NAPP-II). Several trials were conducted for circumferential TIG welding of zircaloy. Since zircaloy is highly reactive in nature, good shielding with inert gas should be ensured to avoid weld contamination due to oxygen and nitrogen. The strength, microstructural and radiographical requirements were examined with different parameters of welding such as weld current, feed, inert gas flow and weld configuration. The strength and other requirements were achieved meeting stringent specifications and assemblies for KAPP-I were successfully completed and despatched. (author). 7 figs

  3. Instantaneous Decrease in Left Ventricular Afterload during Transcatheter Aortic Valve Implantation Results in Immediate Changes in Left Ventricular Strain.

    Science.gov (United States)

    Swan, Amy; Prakash, Roshan; Chew, Derek P; Perry, Rebecca; Sinhal, Ajay; Selvanayagam, Joseph B; Joseph, Majo X

    2016-05-01

    Severe aortic stenosis causes chronic increased afterload on the left ventricle (LV) resulting in myocardial hypertrophy and ultimately dysfunction if left untreated. Transcatheter aortic valve implantation (TAVI) immediately decreases the afterload on the LV by reducing the pressure gradient through the aortic valve. In our study, we aim to evaluate immediate changes in LV mechanics using intra-procedural transesophageal echocardiography (TEE) to assess circumferential and radial strain via speckle tracking. Intra-operative TEE was performed during TAVI for 53 patients (mean age 84 ± 8 years). Two-dimensional images in the transgastric view were acquired at the level of the papillary muscle. Circumferential and radial strain was calculated using speckle tracking with Philips Qlab software. Global LV afterload was measured by calculating valvulo-arterial impedance (Zva). Immediately post-TAVI, there was a change in both radial strain rate (Pre: 0.73 ± 0.04 vs. Post: 0.88 ± 0.04 per second, P < 0.001) and circumferential strain rate (-0.53 ± 0.04 (pre) vs. -0.74 ± 0.04 (post) per second, P < 0.001). There was also an immediate improvement in circumferential global strain parameters (-14.5 ± 5% (pre) vs. -16.0 ± 4.7% (post), P < 0.05), whereas there was no significant change seen in global radial strain (15.6 ± 0.8% (pre) vs. 15.2 ± 0.9% (post), P = 0.69). No significant change was seen in LV ejection fraction (51.5 ± 14.2% (pre) vs. 52.1 ± 14.0% (post), P = 0.77). Speckle tracking using TEE images is feasible and identifies significant improvements in LV strain and strain rate immediately following TAVI that is not detected by conventional measure of LV function. PMID:26676176

  4. Cardiac biplane strain imaging: initial in vivo experience

    Energy Technology Data Exchange (ETDEWEB)

    Lopata, R G P; Nillesen, M M; Thijssen, J M; De Korte, C L [Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Verrijp, C N; Lammens, M M Y; Van der Laak, J A W M [Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Singh, S K; Van Wetten, H B [Department of Cardiothoracic Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Kapusta, L [Pediatric Cardiology, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)], E-mail: R.Lopata@cukz.umcn.nl

    2010-02-21

    In this study, first we propose a biplane strain imaging method using a commercial ultrasound system, yielding estimation of the strain in three orthogonal directions. Secondly, an animal model of a child's heart was introduced that is suitable to simulate congenital heart disease and was used to test the method in vivo. The proposed approach can serve as a framework to monitor the development of cardiac hypertrophy and fibrosis. A 2D strain estimation technique using radio frequency (RF) ultrasound data was applied. Biplane image acquisition was performed at a relatively low frame rate (<100 Hz) using a commercial platform with an RF interface. For testing the method in vivo, biplane image sequences of the heart were recorded during the cardiac cycle in four dogs with an aortic stenosis. Initial results reveal the feasibility of measuring large radial, circumferential and longitudinal cumulative strain (up to 70%) at a frame rate of 100 Hz. Mean radial strain curves of a manually segmented region-of-interest in the infero-lateral wall show excellent correlation between the measured strain curves acquired in two perpendicular planes. Furthermore, the results show the feasibility and reproducibility of assessing radial, circumferential and longitudinal strains simultaneously. In this preliminary study, three beagles developed an elevated pressure gradient over the aortic valve ({delta}p: 100-200 mmHg) and myocardial hypertrophy. One dog did not develop any sign of hypertrophy ({delta}p = 20 mmHg). Initial strain (rate) results showed that the maximum strain (rate) decreased with increasing valvular stenosis (-50%), which is in accordance with previous studies. Histological findings corroborated these results and showed an increase in fibrotic tissue for the hearts with larger pressure gradients (100, 200 mmHg), as well as lower strain and strain rate values.

  5. Cardiovascular magnetic resonance myocardial feature tracking detects quantitative wall motion during dobutamine stress

    Directory of Open Access Journals (Sweden)

    Beerbaum Philipp

    2011-10-01

    Full Text Available Abstract Background Dobutamine stress cardiovascular magnetic resonance (DS-CMR is an established tool to assess hibernating myocardium and ischemia. Analysis is typically based on visual assessment with considerable operator dependency. CMR myocardial feature tracking (CMR-FT is a recently introduced technique for tissue voxel motion tracking on standard steady-state free precession (SSFP images to derive circumferential and radial myocardial mechanics. We sought to determine the feasibility and reproducibility of CMR-FT for quantitative wall motion assessment during intermediate dose DS-CMR. Methods 10 healthy subjects were studied at 1.5 Tesla. Myocardial strain parameters were derived from SSFP cine images using dedicated CMR-FT software (Diogenes MRI prototype; Tomtec; Germany. Right ventricular (RV and left ventricular (LV longitudinal strain (EllRV and EllLV and LV long-axis radial strain (ErrLAX were derived from a 4-chamber view at rest. LV short-axis circumferential strain (EccSAX and ErrSAX; LV ejection fraction (EF and volumes were analyzed at rest and during dobutamine stress (10 and 20 μg · kg-1· min-1. Results In all volunteers strain parameters could be derived from the SSFP images at rest and stress. EccSAX values showed significantly increased contraction with DSMR (rest: -24.1 ± 6.7; 10 μg: -32.7 ± 11.4; 20 μg: -39.2 ± 15.2; p SAX increased significantly with dobutamine (rest: 19.6 ± 14.6; 10 μg: 31.8 ± 20.9; 20 μg: 42.4 ± 25.5; p SAX and worst for RV longitudinal strain (EllRV as determined by 95% confidence intervals of the difference. Conclusions CMR-FT reliably detects quantitative wall motion and strain derived from SSFP cine imaging that corresponds to inotropic stimulation. The current implementation may need improvement to reduce observer-induced variance. Within a given CMR lab; this novel technique holds promise of easy and fast quantification of wall mechanics and strain.

  6. Consideration on evaluation of internal pressure creep rupture for tube with circumferential joint

    International Nuclear Information System (INIS)

    The behavior of internal pressure creep rupture of the thin-walled cylinders with circumferential joints is affected by the combination of creep characteristics of parent materials and weld metals. In particular, the compatibility of the creep strain rate of parent materials and weld metals becomes an important controlling factor. The behavior of internal pressure creep of the welded parts in circumferential joint cylinders can be evaluated simply with the uniaxial creep data of parent materials and weld metals, considering it by approximately substituting with the creep behavior of a uniaxial longitudinal joint. The method of evaluation is, first, to analyze the breaking behavior of uniaxial longitudinal joints using the uniaxial creep characteristic values of parent materials and weld metals, and next, by combining the equation for the relation between the rupture times of uniaxial creep and internal pressure creep with the analyzed breaking behavior of uniaxial joints, the internal pressure creep rupture behavior of the cylinders with circumferential joints can be evaluated. The internal pressure creep behavior of the thin-walled cylinders with circumferential joints, their rupture life and the uniaxial creep rupture life of longitudinal joints, and the examination of Hastelloy X cylinders are reported. (Kako, I.)

  7. Preliminary Validation of Angle-Independent Myocardial Elastography Using MR Tagging in a Clinical Setting

    Science.gov (United States)

    Lee, Wei-Ning; Qian, Zhen; Tosti, Christina L.; Brown, Truman R.; Metaxas, Dimitris N.; Konofagou, Elisa E.

    2014-01-01

    Myocardial Elastography (ME), a radio-frequency (RF) based speckle tracking technique, was employed in order to image the entire two-dimensional (2D) transmural deformation field in full view, and validated against tagged Magnetic Resonance Imaging (tMRI) in normal as well as reperfused (i.e., treated myocardial infarction (MI)) human left ventricles. RF ultrasound and tMRI frames were acquired at the papillary muscle level in 2D short-axis (SA) views at nominal frame rates of 136 (fps; real time) and 33 fps (electrocardiogram (ECG)-gated), respectively. In ultrasound, in-plane, 2D (lateral and axial) incremental displacements were iteratively estimated using one-dimensional (1D) cross-correlation and recorrelation techniques in a 2D search with a 1D matching kernel. In tMRI, cardiac motion was estimated by a template-matching algorithm on a 2D grid-shaped mesh. In both ME and tMRI, cumulative 2D displacements were estimated and then used to estimate 2D Lagrangian finite systolic strains, from which polar (i.e., radial and circumferential) strains, namely angle-independent measures, were further obtained through coordinate transformation. Principal strains, which are angle-independent and less centroid-dependent than polar strains, were also computed and imaged based on the 2D finite strains with a previously established strategy. Both qualitatively and quantitatively, angle-independent ME is shown to be capable of 1) estimating myocardial deformation in good agreement with tMRI estimates in a clinical setting and of 2) differentiating abnormal from normal myocardium in a full left-ventricular view. Finally, the principal strains are suggested to be an alternative diagnostic tool of detecting cardiac disease with the characteristics of their reduced centroid dependence. PMID:18952364

  8. Two-dimentional speckle tracking strain imaging in the assessment of myocardial diastolic function in patients with stable angina pectoris

    Directory of Open Access Journals (Sweden)

    Somaye Farokhnejad

    2015-06-01

    Full Text Available Introduction: Ischemic heart disease is caused mainly by obstruction of coronary arteries. The ischemic assessment through echocardiography is dependent on wall motion abnormality detection during systole. In patients with ischemic heart disease the diastolic function is impaired before systolic function and measurement of regional diastolic dysfunction if possible will be most sensitive for assessment of obstructed coronary artery region. This study was designed to determine whether regional left ventricular delayed relaxation diagnosis could be detected with strain imaging derived from two-dimensional speckle-tracking echocardiography in patients with coronary artery disease.Methods: All the articles reviewed were obtained using MEDLINE & ScienceDirect (up to October 2014. All data extracted by speckle tracking echocardiography. The index which is used is strain imaging diastolic index which is calculated as: (A-B A×100  . A is the amount of strain at the time Aortic value closure and B is the amount of strain in first one-third point of diastolic duration.Result: Four articles were reviewed. Three articles assessed patients with echocardiography at rest and one with stress echocardiography. All articles showed the coronary artery tracking with significant stenosis is possible by regional deformation analysis through two-dimensional strain.Discussion: The usage of strain images obtained through two-dimensional speckle tracking has been validated for the quantitation assessment of regional dysfunction in ischemic heart disease. Regional LV delayed relaxation diagnosis with strain imaging is a reliable method after treadmill stress test.Conclusion:  Strain imaging is reasonable for evaluation of ischemia as a low cost noninvasive test with high accuracy.

  9. Assessment of left ventricular segmental function after autologous bone marrow stem cells transplantation in patients with acute myocardial infarction by tissue tracking and strain imaging

    Institute of Scientific and Technical Information of China (English)

    RUAN Wen; PAN Cui-zhen; HUANG Guo-qian; LI Yan-lin; GE Jun-bo; SHU Xian-hong

    2005-01-01

    Background Emerging evidence suggests that stem cells can be used to improve cardiac function in patients after acute myocardial infarction. In this randomized trial, we aimed to use Doppler tissue tracking and strain imaging to assess left ventricular segmental function after intracoronary transfer of autologous bone-marrow stem cells (BMCs) for 6 months' follow up. Methods Twenty patients with acute myocardial infarction and anterior descending coronary artery occlusion proven by angiography were double-blindedly randomized into intracoronary injection of bone-marrow cell (treated, n=9) or diluted serum (control, n=11) groups. GE vivid 7 and Q-analyze software were used to perform echocardiogram in both groups 1 week, 3 months and 6 months after treatment. Three apical views of tissue Doppler imaging were acquired to measure peak systolic displacement (Ds) and peak systolic strain (εpeak) from 12 segments of LV walls. Left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV) were obtained by Simposon's biplane method. Results (1) 3 months later, Ds and εpeak over the infract-related region clearly increased in the BMCs group [Ds: (4.49±2.71) mm vs (7.56±2.95) mm, P0.05; εpeak : (-13.84±6.05)% vs (-15.04±6.75)%, P>0.05]. At the same time, Ds over the normal region also increased, but the Ds enhancement was markedly higher in the BMCs group than that in the control group [(3.21±3.17) mm vs (0.76±1.94) mm, P0.05). (2) LVEF in treated and control groups were almost the same at baseline (1st week after PCI) [(53.37±8.92)% vs (53.51±5.84)%, P>0.05]. But 6 months later, LVEF in the BMCs group were clearly higher than that in the control group [(59.33±12.91)% vs (50.30±8.30)%, P0.05; ESV: (57.12±18.66) ml vs (62.09±17.68) ml, P>0.05]. Three months later, EDV and ESV in the control group were markedly greater than those in the BMCs group [EDV: (154.89±46.34) ml vs (104.85±33.21) ml, P0.05). Conclusions Emergency

  10. Effect of circumferential wave number on stability of suspension flow

    Directory of Open Access Journals (Sweden)

    Wang Feng-Hui

    2014-01-01

    Full Text Available The linear stability analysis is carried out for the suspension flow of spherical particles between a rotating inner cylinder and a stationary concentric outer cylinder. The mass conservation equation and Navier-Stokes equation are applied to the continuous fluid phase and the particle phase. Results of stability analysis show that the increase of wave number in the circumferential direction attenuates the effect of the axial wave number on the amplification factor. The ratio of particle density to fluid density increasing above 0.1 amplifies the flow instability, while it can be weakened with higher circumferential direction wave number. Effect of the critical Taylor number on the amplification factor is reduced by increasing the circumferential direction wave number. The flow stability is affected by the geometry of flow field (the radius ratio at non-zero circumferential direction wave numbers.

  11. Global left ventricular longitudinal strain is closely associated with increased neurohormonal activation after acute myocardial infarction in patients with both reduced and preserved ejection fraction

    DEFF Research Database (Denmark)

    Ersbøll, Mads; Valeur, Nana; Mogensen, Ulrik Madvig;

    2012-01-01

    N-terminal pro brain natriuretic peptide (NT-proBNP) is released in response to increased myocardial wall stress and is associated with adverse outcome in acute myocardial infarction. However, little is known about the relationship between longitudinal deformation indices and NT-proBNP....

  12. Myocardial Bridge

    Science.gov (United States)

    ... Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic ... Related terms: myocardium, coronary arteries, myocardial ischemia Your heart is made of muscle, called the myocardium. The ...

  13. Myocardial Bridging.

    Science.gov (United States)

    Yuan, Shi-Min

    2016-02-01

    Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results. PMID:27074276

  14. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  15. Inter-study reproducibility of cardiovascular magnetic resonance myocardial feature tracking

    Directory of Open Access Journals (Sweden)

    Morton Geraint

    2012-06-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT is a recently described method of post processing routine cine acquisitions which aims to provide quantitative measurements of circumferentially and radially directed ventricular wall strain. Inter-study reproducibility is important for serial assessments however has not been defined for CMR-FT. Methods 16 healthy volunteers were imaged 3 times within a single day. The first examination was performed at 0900 after fasting and was immediately followed by the second. The third, non-fasting scan, was performed at 1400. CMR-FT measures of segmental and global strain parameters were calculated. Left ventricular (LV circumferential and radial strain were determined in the short axis orientation (EccSAX and ErrSAX respectively. LV and right ventricular longitudinal strain and LV radial strain were determined from the 4-chamber orientation (EllLV, EllRV, and ErrLAX respectively. LV volumes and function were also analysed. Inter-study reproducibility and study sample sizes required to demonstrate 5% changes in absolute strain were determined by comparison of the first and second exams. The third exam was used to determine whether diurnal variation affected reproducibility. Results CMR-FT strain analysis inter-study reproducibility was variable. Global strain assessment was more reproducible than segmental analysis. Overall EccSAX was the most reproducible measure of strain: coefficient of variation (CV 38% and 20.3% and intraclass correlation coefficient (ICC 0.68 (0.55-0.78 and 0.7 (0.32-0.89 for segmental and global analysis respectively. The least reproducible segmental measure was EllRV: CV 60% and ICC 0.56 (0.41-0.69 whilst the least reproducible global measure was ErrLAX: CV 33.3% and ICC 0.44 (0–0.77. Variable reproducibility was also reflected in the calculated sample sizes, which ranged from 11 (global EccSAX to 156 subjects (segmental EllRV. The

  16. Net-section limit moments and approximate J estimates for circumferential cracks at the interface between elbows and pipes

    International Nuclear Information System (INIS)

    This paper firstly presents net-section limit moments for circumferential through-wall and part-through surface cracks at the interface between elbows and attached straight pipes under in-plane bending. Closed-form solutions are proposed based on fitting results from small strain FE limit analyses using elastic-perfectly plastic materials. Net-section limit moments for circumferential cracks at the interface between elbows and attached straight pipes are found to be close to those for cracks in the centre of elbows, implying that the location of the circumferential crack within an elbow has a minimal effect on the net-section limit moment. Accordingly it is also found that the assumption that the crack locates in a straight pipe could significantly overestimate the net-section limit load (and thus maximum load-carrying capacity) of the cracked component. Based on the proposed net-section limit moment, a method to estimate elastic-plastic J based on the reference stress approach is proposed for circumferential cracks at the interface between elbows and attached straight pipes under in-plane bending.

  17. GUIDED CIRCUMFERENTIAL WAVES IN DOUBLE-WALLED CARBON NANOTUBES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotube has been taken into account in the model. The dispersion curves of the guided circumferential wave propagation are studied, and some dispersion characteristics are illustrated by comparing with those of single-walled carbon nanotubes. It is found that in double-walled carbon nanotubes, the guided circumferential waves will propagate in more dispersive ways. More interactions between neighboring wave modes may take place. In particular, it has been found that a couple of wave modes may disappear at a certain frequency and that, while a couple of wave modes disappear, another new couple of wave modes are excited at the same wave number.

  18. Circumferential gap propagation in an anisotropic elastic bacterial sacculus

    CERN Document Server

    Taneja, Swadhin; Rutenberg, Andrew D

    2013-01-01

    We have modelled stress concentration around small gaps in anisotropic elastic sheets, corresponding to the peptidoglycan sacculus of bacterial cells, under loading corresponding to the effects of turgor pressure in rod-shaped bacteria. We find that under normal conditions the stress concentration is insufficient to mechanically rupture bacteria, even for gaps up to a micron in length. We then explored the effects of stress-dependent smart-autolysins, as hypothesised by Arthur L Koch [Advances in Microbial Physiology 24, 301 (1983); Research in Microbiology 141, 529 (1990)]. We show that the measured anisotropic elasticity of the PG sacculus can lead to stable circumferential propagation of small gaps in the sacculus. This is consistent with the recent observation of circumferential propagation of PG-associated MreB patches in rod-shaped bacteria. We also find a bistable regime of both circumferential and axial gap propagation, which agrees with behavior reported in cytoskeletal mutants of B. subtilis. We con...

  19. Structural and leakage integrity of tubes affected by circumferential cracking

    Energy Technology Data Exchange (ETDEWEB)

    Hernalsteen, P. [TRACTEBEL, Brussels (Belgium)

    1997-02-01

    In this paper the author deals with the notion that circumferential cracks are generally considered unacceptable. He argues for the need to differentiate two facets of such cracks: the issue of the size and growth rate of a crack; and the issue of the structural strength and leakage potential of the tube in the presence of the crack. In this paper the author tries to show that the second point is not a major concern for such cracks. The paper presents data on the structural strength or burst pressure characteristics of steam generator tubes derived from models and data bases of experimental work. He also presents a leak rate model, and compares the performance of circumferential and axial cracks as far as burst strength and leak rate. The final conclusion is that subject to improvement in NDE capabilities (sizing, detection, growth), that Steam Generator Defect Specific Management can be used to allow circumferentially degraded tubes to remain in service.

  20. Circumferential fusion improves outcome in comparison with instrumented posterolateral fusion

    DEFF Research Database (Denmark)

    Videbaek, Tina S; Christensen, Finn B; Soegaard, Rikke;

    2006-01-01

    STUDY DESIGN: Prospective randomized clinical study with a 5- to 9-year follow-up period. OBJECTIVE: The aim of the present study was to analyze the long-term outcome with respect to functional disability, pain, and general health of patients treated by means of circumferential lumbar fusion...... in comparison with those treated by means of instrumented posterolateral lumbar fusion. SUMMARY OF BACKGROUND DATA: Circumferential fusion has become a common procedure in lumbar spinal fusion both as a primary and salvage procedure. However, the claimed advantages of circumferential fusion over conventional...... posterolateral fusion lack scientific documentation. (The primary report with a 2-year follow-up has been published in Spine in 2002.) METHODS: From April 1996 to November 1999, a total of 148 patients (mean age, 45 years) with severe chronic low back pain were randomly selected for either posterolateral lumbar...

  1. Circumferential wires as a supplement to intramedullary nailing in unstable trochanteric hip fractures

    DEFF Research Database (Denmark)

    Ban, Ilija; Birkelund, Lasse; Palm, Henrik;

    2012-01-01

    Fixation of unstable trochanteric fractures is challenging. Application of a circumferential wire may facilitate bone contact and avoid postoperative fracture displacement. However, the use of circumferential wires remains controversial due to possible disturbance of the blood supply to the under...

  2. 斑点追踪成像技术在心肌梗死左室心肌应变能力中的应用%Application of Speckle Tracking Imaging in Left Ventricular Strain Capacity of Myocardial Infarction

    Institute of Scientific and Technical Information of China (English)

    喻丽华; 赵季红; 蔡伟; 李学文

    2012-01-01

    目的:探讨超声斑点追踪成像(speckle tracking imaging,STI)技术评价心肌梗死患者左室心肌整体和局部应变的价值.方法:收集医院60例确诊为前壁心肌梗死患者,将同期体检健康志愿者60例作为正常对照.分别收集2组心尖位左室长轴3个切面高帧频二维动态图像,以自动功能成像软件(automated functional imaging,AFI)测量左室18节段峰值收缩期应变(S)、切面峰值收缩应变(GLS)及左室长轴平均总应变(GLS-Avg),分析GLS-Avg与左室射血分数(left ventricular ejection fraction,LVEF)的相关性;比较2组患者GLS-Avg.结果:前壁心肌梗死患者左室18节段S值自基底段向心尖段逐渐增加,各壁间差异无统计学意义(P>0.05);前壁心肌梗死患者各节段壁应变绝对值低于正常对照组(P<0.05).GLS-Avg与LVEF具有良好相关性(r=0.93,P<0.05).结论:斑点追踪成像技术能定量测定心肌梗死患者左室和整体心肌的变化.%Objective To study the application of speckle tracking imaging(STI) technology in myocardial infarction patients with left ventricular global and local strain. Methods Sixty cases of myocardial infarction patients were selected, and another sixty healthy patients were in control group. Left ventricular apical long-axis positions were recorded in three two-dimensional slices of high frame rate dynamic images. Left ventricular peak systolic strain in paragraph 18(S), the section peak systolic strain(GLS) and left ventricular long axis of the average total strain(GLS-Avg) of all cases were measured by automated functional imaging(AFI). The relationship of GLS-Avg and left ventricular ejection fraction(LVEF) was analyzed. Results Paragraph 18(S) values of left ventricle from the basal to apical segments gradually increased in control group. The intramural difference was not statistically significant(P>0.05), and strain of the wall segment in myocardial infarction group was lower than that of the control

  3. Circumferential buckling instability of a growing cylindrical tube

    KAUST Repository

    Moulton, D.E.

    2011-03-01

    A cylindrical elastic tube under uniform radial external pressure will buckle circumferentially to a non-circular cross-section at a critical pressure. The buckling represents an instability of the inner or outer edge of the tube. This is a common phenomenon in biological tissues, where it is referred to as mucosal folding. Here, we investigate this buckling instability in a growing elastic tube. A change in thickness due to growth can have a dramatic impact on circumferential buckling, both in the critical pressure and the buckling pattern. We consider both single- and bi-layer tubes and multiple boundary conditions. We highlight the competition between geometric effects, i.e. the change in tube dimensions, and mechanical effects, i.e. the effect of residual stress, due to differential growth. This competition can lead to non-intuitive results, such as a tube growing to be thinner and yet buckle at a higher pressure. © 2011 Elsevier Ltd. All rights reserved.

  4. Fracture toughness evaluation of circumferentially-cracked round bars

    International Nuclear Information System (INIS)

    The measure of the fracture toughness of a circumferentially-cracked round bar is generally performed through approximate formulae. Comparison of existing formulae to finite element results does not always show good agreement. Therefore an eta factor is introduced in order to improve the existing analytical formula. The axisymmetrical geometry is generally considered to be a high constrained geometry. Finite element calculations are performed to verify and quantify the constraint relative to the three point bending configuration (precracked Charpy)

  5. Ground and microgravity results of a circumferentially microgrooved capillary evaporator

    International Nuclear Information System (INIS)

    A circumferentially microgrooved capillary evaporator is here proposed as a reliable alternative for ground and spacecraft thermal control system applications. In this paper, experimental results concerning the start-up and thermal behavior of a capillary evaporator at steady state operation are presented. A capillary pumped loop was developed and tested at ground and microgravity conditions, using deionized water as the working fluid. The capillary evaporator has internally machined circumferential grooves with an average opening of 33 μm opening at 215 μm step into a 19.05 mm (3/4 in) diameter aluminum tube. The corresponding capillary pumping pressure is about 1.5 kPa. In both tests, power inputs up to 10 W (4.55 kW/m2) were successfully applied to the external surface of the evaporator, showing good performance under ground and microgravity conditions. The capillary evaporator as proposed proved to be a reliable alternative for industrial and space applications. - Highlights: • Circumferentially grooved capillary evaporators as alternative for thermal control. • Successful start-up operation at ground and microgravity conditions. • Successful steady state operation at ground and microgravity conditions. • Easy repriming in case of dry-out

  6. The Prognostic Value of Left Atrial Peak Reservoir Strain in Acute Myocardial Infarction Is Dependent on Left Ventricular Longitudinal Function and Left Atrial Size

    DEFF Research Database (Denmark)

    Ersbøll, Mads; Andersen, Mads J; Valeur, Nana; Mogensen, Ulrik Madvig; Waziri, Homa; Møller, Jacob Eifer; Hassager, Christian; Søgaard, Peter; Køber, Lars

    2013-01-01

    Peak atrial longitudinal strain (PALS) during the reservoir phase has been proposed as a measure of left atrium function in a range of cardiac conditions, with the potential for added pathophysiological insight and prognostic value. However, no studies have assessed the interrelation of PALS and...... left ventricular longitudinal strain (global longitudinal strain) in large-scale populations in regard to prognosis....

  7. Strain dyssynchrony index determined by three-dimensional speckle area tracking can predict response to cardiac resynchronization therapy

    Directory of Open Access Journals (Sweden)

    Onishi Tetsuari

    2011-04-01

    Full Text Available Abstract Background We have previously reported strain dyssynchrony index assessed by two-dimensional speckle tracking strain, and a marker of both dyssynchrony and residual myocardial contractility, can predict response to cardiac resynchronization therapy (CRT. A newly developed three-dimensional (3-D speckle tracking system can quantify endocardial area change ratio (area strain, which coupled with the factors of both longitudinal and circumferential strain, from all 16 standard left ventricular (LV segments using complete 3-D pyramidal datasets. Our objective was to test the hypothesis that strain dyssynchrony index using area tracking (ASDI can quantify dyssynchrony and predict response to CRT. Methods We studied 14 heart failure patients with ejection fraction of 27 ± 7% (all≤35% and QRS duration of 172 ± 30 ms (all≥120 ms who underwent CRT. Echocardiography was performed before and 6-month after CRT. ASDI was calculated as the average difference between peak and end-systolic area strain of LV endocardium obtained from 3-D speckle tracking imaging using 16 segments. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, Yu Index, and two-dimensional radial dyssynchrony by speckle-tracking strain. Response was defined as a ≥15% decrease in LV end-systolic volume 6-month after CRT. Results ASDI ≥ 3.8% was the best predictor of response to CRT with a sensitivity of 78%, specificity of 100% and area under the curve (AUC of 0.93 (p Conclusions ASDI can predict responders and LV reverse remodeling following CRT. This novel index using the 3-D speckle tracking system, which shows circumferential and longitudinal LV dyssynchrony and residual endocardial contractility, may thus have clinical significance for CRT patients.

  8. Circumferential Calcification of Silicone Implant Misunderstood as a Bony Substitute.

    Science.gov (United States)

    Lee, Sae Bin; Min, Hyun Jin

    2016-01-01

    Silicone implant is known to be safe and easy to handle, and frequently used in Asian rhinoplasty. Compared with breast implant, complication studies about silicone calcification used in rhinoplasty are very limited. Recently, the authors experienced an interesting patient who underwent revision rhinoplasty in our institution. Based on preoperative images, previously inserted dorsal augmentation material was identified. It was circumferentially enclosed with bony material and hypertrophied bony lesion induced hump on the mid portion of nasal dorsum. During operation, the authors found it was the calcified capsule of silicone implant, and the calcification was surrounding the whole implant material. PMID:26703034

  9. Circumferential skin defect - Ilizarov technique in plastic surgery

    Directory of Open Access Journals (Sweden)

    Madhuri Vrisha

    2004-01-01

    Full Text Available A young man had an open fracture of the tibia with bone and soft tissue loss in the distal part of the left leg following a crush injury. The circumferential skin defect was successfully treated with controlled lengthening of the distal skin by the Ilizarov technique using nylon wires and skin staples to apply traction. This was combined with limb reconstruction done simultaneously using orthofix external fixator. This case report highlights the use of an orthopaedic technique to provide skin cover in distal leg.

  10. Lessons Learned After 15 Years of Circumferential Bodylift Surgery.

    Science.gov (United States)

    Small, Kevin H; Constantine, Ryan; Eaves, Felmont F; Kenkel, Jeffrey M

    2016-06-01

    Circumferential bodylift is a powerful procedure for achieving dramatic and natural body contouring changes in the massive weight loss patient. The care of these patients has raised our awareness of several important issues including safety, nutritional status, skin quality, recurrent laxity, surgical steps, and postoperative scars. Integration of this knowledge with various technical modifications over the last 15 years has improved our care for this cohort. We have not only seen a rise in the number of surgeries performed, but also the development of principles, techniques, and details that the authors feel necessary to share to achieve improved contour and more predictable outcomes. LEVEL OF EVIDENCE 4: Therapeutic. PMID:26821642

  11. DETERMINATION OF EFFICIENCY OF THE CIRCUMFERENTIAL DRAINAGE SYSTEM

    Directory of Open Access Journals (Sweden)

    Maciej Kroll

    2015-11-01

    Full Text Available One of the potential alternatives to improve the stability coefficient for an embankment structure is to flatten the filtration curve. As a result, we obtain lower body forces triggering the potential landslide and more advantageous soil strength parameters, which counteract landslide movements. In the case of waste dumps lowering the phreatic surface of waters is achieved thanks to the construction of auxiliary drainage systems, meeting the guidelines for their safe operation. The aim of this paper is to indicate a method facilitating the determination of the actual position of the phreatic surface within the deposited sediments and the assessment of efficiency of the circumferential drainage system in the waste dump. It was decided in this study to apply cone penetration test CPTU. The CPTU made it possible to measure dissipation of excess water pressure in pores identifying drainage conditions, which were compared with the results of piezometric measurements. The results of these tests made it possible to monitor changes in the position of the depression curve of supernatant waters in dams and to determine the efficiency of the circumferential drainage system.

  12. Hydrogen Effect on the Circumferential Mechanical Properties of HANA-4 and HANA-6 Cladding Tubes

    International Nuclear Information System (INIS)

    KAERI has been doing a lot of out-of pile tests including an in-pile test to verify the performance of HANA cladding tubes for a high burn-up fuel rod, developed by them. When a zirconium alloy is used in a nuclear reactor, hydrides form in it from not only external hydrogen sources such as a waterside corrosion, dissolved hydrogen in a coolant, water radiolysis but also internal sources such as the hydrogen content in fuel pellets and the moisture absorbed by a uranium dioxide fuel pellet. Hydrides may act as a sudden failure at a very low strain. For low and medium hydrogen content, the hydrides crack during a tensile loading and accelerate the ductile fracture process. As a kind of simulation test to obtain the estimated data of HANA cladding tubes in a high burn-up state, the hydrogen effect on the axial tensile properties of a HANA-4(Zr-1.5Nb-0.0.4Sn- 0.21Fe-0.1Cu) cladding tube and that on the burst properties of HANA-4 and HANA-6 (Zr-1.1Nb-0.05Cu) cladding tubes was already studied. This study was also done to characterize the effect of hydrogen on the circumferential mechanical properties of HANA-4 and HANA-6 cladding tubes by a ring tension test at both room temperature and 350 .deg. C. Additional tests were also done on both Zircaloy-4 (Zr-1.26Sn-0.23Fe-0.12Cr) and A (Zr-1.0Nb-0.99Sn-0.11Fe) cladding tubes of a commercial grade to compare the hydrogen effect on their circumferential properties with that on the properties of the HANA-4 and HANA-6 cladding tubes

  13. New Syndrome of Congenital Circumferential Skin Folds Associated with Multiple Congenital Anomalies

    OpenAIRE

    Basel-Vanagaite, Lina; Sprecher, Eli; Gat, Andrea; Merlob, Paul; Albin-Kaplanski, Adi; Konen, Osnat; Solomon, Benjamin D.; Muenke, Maximilian; Grzeschik, Karl H; Sirota, Lea

    2011-01-01

    Congenital circumferential skin folds can be found in individuals with no additional defects, as well as in patients with multiple congenital anomalies and developmental abnormalities. Current data point to etiological heterogeneity of syndromic cases. We describe a 7-month-old girl with a novel combination of symmetrical congenital circumferential skin folds, dysmorphic features, and multiple congenital abnormalities. Examination of the patient revealed symmetrical congenital circumferential...

  14. Characterization of mechanical and geometrical properties of a tube with axial and circumferential guided waves.

    Science.gov (United States)

    Yeh, Cheng-Hung; Yang, Che-Hua

    2011-05-01

    Guided waves propagating in cylindrical tubes are frequently applied for the characterization of material or geometrical properties of tubes. In a tube, guided waves can propagate in the axial direction and called axial guided waves, or in the circumferential direction called circumferential guided waves. Dispersion spectra for the axial and circumferential guided waves share some common behaviors and however exhibit some particular behaviors of their own. This study provides an investigation with theoretical modeling, experimental measurements, and a simplex-based inversion procedure to explore the similarity and difference between the axial guided waves and circumferential guided waves, aiming at providing useful information while axial and circumferential guided waves are applied in the area of material characterization. The sensitivity to the radius curvature for the circumferential guided waves dispersion spectra is a major point that makes circumferential guided waves different from axial guided waves. For the purpose of material characterization, both axial and circumferential guided waves are able to extract an elastic moduli and wall-thickness information from the dispersion spectra, however, radius information can only be extracted from the circumferential guided waves spectra. PMID:21211810

  15. Tensile and Fracture Properties of Circumferentially Notched Tensile Specimens of Stainless Steel Weldments

    International Nuclear Information System (INIS)

    The tensile and fracture properties of different types of austenitic stainless steel weldments were determined using round notched tensile specimens. These included 304L, 316L and 6%Mo super austenitic stainless steels and their weld metals. The triaxial state of stress, the plastic constraint and the plane strain conditions developed ahead of the notch root make notched specimens eligible for the evaluation of fracture toughness. This was achieved through the testing procedure: J-evaluation on tensile test (JETT) using circumferentially notched round bar specimens. The JETT index was taken as a measure of the relevant elastic-plastic fracture toughness of the tested materials. In the case of austenitic stainless steels being too ductile at room temperature the resulted JETT were of relatively higher values than the fracture toughness values determined from the standard fracture mechanics test methods. This could be related to the difference in the stress state ahead of the sharp crack of the standard fracture mechanics specimen and that of the blunt notch of the tensile specimen. The results showed that the 6% Mo weld metal ranked highest while the 316L weld metal ranked lowest regarding JETT fracture toughness values. The deformation mechanisms pertinent to austenitic stainless steels (generation of stacking faults and formation of strain induced martensite) were employed for the interpretation of the experimental results.

  16. Accurate wall thickness measurement using autointerference of circumferential Lamb wave

    International Nuclear Information System (INIS)

    In this paper, a method of accurately measuring the pipe wall thickness by using noncontact air-coupled ultrasonic transducer (NAUT) was presented. In this method, accurate measurement of angular wave number (AWN) is a key technique because the AWN is changes minutely with the wall thickness. An autointerference of the circumferential (C-) Lamb wave was used for accurate measurements of the AWN. Principle of the method was first explained. Modified method for measuring the wall thickness near a butt weld line was also proposed and its accuracy was evaluated within 6 μm error. It was also shown in the paper that wall thickness measurement was accurately carried out beyond the difference among the sensors by calibrating the frequency response of the sensors. (author)

  17. Transverse shear effect in a circumferentially cracked cylindrical shell

    Science.gov (United States)

    Delale, F.; Erdogan, F.

    1979-01-01

    The objectives of the paper are to solve the problem of a circumferentially-cracked cylindrical shell by taking into account the effect of transverse shear, and to obtain the stress intensity factors for the bending moment as well as the membrane force as the external load. The formulation of the problem is given for a specially orthotropic material within the framework of a linearized shallow shell theory. The particular theory used permits the consideration of all five boundary conditions as to moment and stress resultants on the crack surface. The effect of Poisson's ratio on the stress intensity factors and the nature of the out-of-plane displacement along the edges of the crack, i.e., bulging, are also studied.

  18. Transient thermal stress problem for a circumferentially cracked hollow cylinder

    Science.gov (United States)

    Nied, H. F.; Erdogan, F.

    1982-01-01

    The transient thermal stress problem for a hollow elasticity cylinder containing an internal circumferential edge crack is considered. It is assumed that the problem is axisymmetric with regard to the crack geometry and the loading, and that the inertia effects are negligible. The problem is solved for a cylinder which is suddenly cooled from inside. First the transient temperature and stress distributions in an uncracked cylinder are calculated. By using the equal and opposite of this thermal stress as the crack surface traction in the isothermal cylinder the crack problem is then solved and the stress intensity factor is calculated. The numerical results are obtained as a function of the Fourier number tD/b(2) representing the time for various inner-to-outer radius ratios and relative crack depths, where D and b are respectively the coefficient of diffusivity and the outer radius of the cylinder.

  19. Influence of circumferential flaw length on internal burst pressure of a wall-thinned pipe

    International Nuclear Information System (INIS)

    Highlights: ► The effect of θ on pf was examined by experimental analysis and FEA. ► Here θ is the circumferential angle of a flaw, pf is the internal burst pressure. ► pf decreased as θ increased in some cases. ► The effect of θ on pf should be taken into consideration in evaluating pf. -- Abstract: This paper examines the effect of the circumferential angle of a flaw θ on the internal burst pressure pf of pipes with artificial wall-thinned flaws. The effect of θ has conventionally been regarded as unimportant in the evaluation of the pf of wall-thinned straight pipes. Therefore, a burst pressure equation for an axial crack inside a cylinder (Fig. 1, left), such as Kiefner's equation (Kiefner et al., 1973), has been widely applied (ANSI/ASME B31.G., 1991; Hasegawa et al., 2011). However, the following implicit assumptions notably exist when applying the equation to planar flaws in situations with non-planar flaws. 1)The fracture mode of the non-planar flaw under consideration is identical to that of the crack. 2)The effect of θ on pf, which is not considered for an axial crack, is small or negligible. However, the experimental results from the systematic burst tests for carbon steel pipes with artificial wall-thinned flaws examined in this paper showed that these implicit assumptions may be incorrect. In this paper the experimental results are evaluated in further detail. The purpose of the evaluation was to clarify the effect of θ on pf. Specifically, the significance of the flaw configuration (axial length δz and wall-thinning ratio t1/t) was studied for its effects on θ and pf. In addition, a simulation of this effect was conducted using a large strain elastic-plastic Finite Element Analysis (FEA) model. As observed from the experimental results, θ tended to affect pf in cases with large δz, and t1/t was also correlated with a decrease in pf with an increase in θ. These tendencies were successfully simulated by the large strain elastic

  20. Myocardial contractility

    Energy Technology Data Exchange (ETDEWEB)

    Comet, M.; Machecourt, J.

    1988-01-01

    The myocardial contractility characterizes the intensity of the activation representing the globality of the processes which lead to the formation of the sites where the strength is generated. Some parameters allowing a quantification of the contractility are measured during the isovolumic phase of the ventricular contraction: they are essentially dP/dt/sub max/, and eventually V/sub max/. For the measurement of these parameters, a pressure detector needs to be introduced into the left ventricle. Other parameters are measured during the systolic ejection phase: they are the ejection fraction, which is easy to measure and is very load dependant, and the maximal elastance. This last parameter is not easy to measure, but seems load independant. With the radioisotopes, it is possible to measure the ejection fraction and the maximal elastance. Contractility measurements are of interest in the study of ischemic cardiopathies and of valvular desease.

  1. Analysis of circumferential waves on a water-filled cylindrical shell

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; ZHENG Guoyin; FAN Jun

    2012-01-01

    The formation of scattering field from a water-filled cylindrical shell was studied. The analytic solutions of scattering field are derived using elastic thin shell theory and Sommerfeld-Watson Transformation (SWT) method. Complex wave-number poles of circumferential waves are found numerically, the phase speed and attenuation of circumferential waves between the situation of a hollow cylindrical shell and a water-filled cylindrical shell are compared. The synthesis of backscattering form functions which are sum of specular reflection component and circumferential waves is consistent with normal mode result. The calculated echo sequences of additional fluid circumferential waves are compared with experimental results. The results show that richer resonance peaks appeared in the backscattering form functions of a water-filled cylindrical shell and the formation of echo's structure are due to re-radiation effects of additional fluid circumferential waves.

  2. Three-dimensional circumferential strain in evaluating changes of left ventricular myocardial contractional function in early chronic kidney disease patients%三维圆周应变评价早期慢性肾病患者左心室心肌收缩功能变化

    Institute of Scientific and Technical Information of China (English)

    刘开薇; 任卫东; 孙璐; 宋光; 刘慧

    2016-01-01

    目的 采用三维整体圆周应变(GCS)评价早期慢性肾病(CKD)患者左心室心肌收缩功能.方法 选取26例CKD2期患者(CKD2期组)、20例CKD3期(CKD3期组)患者及30名健康志愿者(对照组).对所有受检者行常规二维超声心动图和三维斑点追踪成像(3D-STE),测量并比较常规超声心动图指标,包括左心室舒张末期间间隔厚度(IVSTd)、左心室舒张末期内径(LVEDd)、左心室舒张末期后壁厚度(LVPWTd)、左心室舒张末期容积(EDV)和收缩末期容积(ESV),以及3D-STE指标,包括三维左心室射血分数(3D-LVEF)、三维左心室心肌质量指数(3D-LVMi)及左心室GCS.结果 与对照组比较,CKD2期组的IVSTd增大,LVEDd、GCS减小;CKD3期组的IVSTd、LVESV、3D-LVMi增大,LVEDd、3D-LVEF、GCS减小;与CKD2期组比较,CKD3期组的IVSTd、3D-LVMi增大,LVEDd、GCS减小,以上差异均有统计学意义(P均<0.05).结论 早期CKD患者左心室心肌收缩功能已减低,可通过GCS进行评价.

  3. Cardiovascular magnetic resonance feature-tracking assessment of myocardial mechanics: Intervendor agreement and considerations regarding reproducibility

    International Nuclear Information System (INIS)

    Aim: To assess intervendor agreement of cardiovascular magnetic resonance feature tracking (CMR-FT) and to study the impact of repeated measures on reproducibility. Materials and methods: Ten healthy volunteers underwent cine imaging in short-axis orientation at rest and with dobutamine stimulation (10 and 20 μg/kg/min). All images were analysed three times using two types of software (TomTec, Unterschleissheim, Germany and Circle, cvi42, Calgary, Canada) to assess global left ventricular circumferential (Ecc) and radial (Err) strains and torsion. Differences in intra- and interobserver variability within and between software types were assessed based on single and averaged measurements (two and three repetitions with subsequent averaging of results, respectively) as determined by Bland–Altman analysis, intraclass correlation coefficients (ICC), and coefficient of variation (CoV). Results: Myocardial strains and torsion significantly increased on dobutamine stimulation with both types of software (p<0.05). Resting Ecc and torsion as well as Ecc values during dobutamine stimulation were lower measured with Circle (p<0.05). Intra- and interobserver variability between software types was lowest for Ecc (ICC 0.81 [0.63–0.91], 0.87 [0.72–0.94] and CoV 12.47% and 14.3%, respectively) irrespective of the number of analysis repetitions. Err and torsion showed higher variability that markedly improved for torsion with repeated analyses and to a lesser extent for Err. On an intravendor level TomTec showed better reproducibility for Ecc and torsion and Circle for Err. Conclusions: CMR-FT strain and torsion measurements are subject to considerable intervendor variability, which can be reduced using three analysis repetitions. For both vendors, Ecc qualifies as the most robust parameter with the best agreement, albeit lower Ecc values obtained using Circle, and warrants further investigation of incremental clinical merit. -- Highlights: •This is the first comparison

  4. Prediction of pressure tube ballooning under non-uniform circumferential temperature gradients and high internal pressure

    International Nuclear Information System (INIS)

    In some accident scenarios in CANDU reactors the pressure tube is expected to reach sufficiently high temperature at high internal pressure such that the pressure tube expands radially, i.e., the pressure tube balloons.Under these conditions it is of importance to the assessment of fuel channel integrity to be able to accurately predict the timing and extent of pressure tube ballooning. If the circumferential temperature gradient on the pressure tube is non-uniform, the resulting transverse hoop stress is non-uniform and the pressure tube experiences a non-uniform ballooning. This could result in a failure of the pressure tube before it balloons into contact with the surrounding calandria tube. The fuel channel integrity code SMARTT (Simulation Method for Azimuthal and Radial Temperature Transients) is used to predict the ballooning of CANDU Zr-2.5wt%Nb pressure tubes. The pressure tube strain rate calculation in SMARTT was extracted and used as the basis for the code PTSTRAIN which was constructed to model pressure tube ballooning with the temperature of the pressure tube and the internal pressure specified as the boundary conditions for the calculation. The main objectives of this paper are to describe the comparison of the predictions of this code against two different sets of experiments which were performed with defected and non-defected pressure tubes, and to provide further validation of the pressure tube ballooning model against independent experiments. (author)

  5. Simplified method of calculating residual stress in circumferential welding of piping

    International Nuclear Information System (INIS)

    Many circumferential joints of piping are used in as-welded state, but in these welded joints, the residual stress as high as the yield stress of materials arises, and causes to accelerate stress corrosion cracking and corrosion fatigue. The experiment or the finite element method to clarify welding residual stress requires much time and labor, and is expensive, therefore, the author proposed the simplified method of calculation. The heating and cooling process of welding is very complex, and cannot be modeled as it is, therefore, it was assumed that in multiple layer welding, the welding condition of the last layer determines the residual stress, that material constants are invariable regardless of temperature, that the temperature distribution and residual stress are axisymmetric, and that there is repeated stress-strain relation in the vicinity of welded parts. The temperature distribution at the time of welding, thermal stress and welding residual stress are analyzed, and the material constants used for the calculation of residual stress are given. As the example of calculation, the effect of welding heat input and materials is shown. The extension of the method to a thick-walled pipe is discussed. (Kako, I.)

  6. Determination of the collapse load of circumferentially cracked pipes

    International Nuclear Information System (INIS)

    Pipes related to the Primary System of PWR reactors are manufactured from high toughness austenitic and ferritic steels, which are resistant to the unstable growth of defects. A flaw in a piping system has to cause a leakage in a considerable rate, before any growth of the flaw causes a catastrophic rupture of the piping. This is the concept of LBB (Leak-Before-Break). If a conservative analysis can demonstrate that this leakage can be detected and repaired before a sudden rupture of the pipe occurs, the regulatory commission can exclude from the design basis, the postulation of a DEGB (Double-Ended Guillotine Break) hypothetic and the considerations to its associated dynamic effects. As a consequence, the protections against dynamic effects can be desconsidered, bringing an immediate economic benefice. In terms of security, the removal of the protections, give also more benefits considering the existence of more space available at the installation for inspection activities. A fundamental stage in the LBB methodology consists in the analysis of the stability of a postulated throughwall flaw in a specific piping system. In this work, the methods DPFAD (Deformation Plasticity Failure Assessment Diagram), J-T Analysis and DFM (Ductile Fracture Method) are described and applied on the determination of the instability load in some piping configurations submitted to bending containing circumferential throughwall flaws, and where geometry and material variations are considered. The instability loads obtained by these methods are compared among them and compared with some experimental results. (author)

  7. Fracture behavior of short circumferentially surface-cracked pipe

    Energy Technology Data Exchange (ETDEWEB)

    Krishnaswamy, P.; Scott, P.; Mohan, R. [Battelle, Columbus, OH (United States)] [and others

    1995-11-01

    This topical report summarizes the work performed for the Nuclear Regulatory Comniission`s (NRC) research program entitled ``Short Cracks in Piping and Piping Welds`` that specifically focuses on pipes with short, circumferential surface cracks. The following details are provided in this report: (i) material property deteminations, (ii) pipe fracture experiments, (iii) development, modification and validation of fracture analysis methods, and (iv) impact of this work on the ASME Section XI Flaw Evaluation Procedures. The material properties developed and used in the analysis of the experiments are included in this report and have been implemented into the NRC`s PIFRAC database. Six full-scale pipe experiments were conducted during this program. The analyses methods reported here fall into three categories (i) limit-load approaches, (ii) design criteria, and (iii) elastic-plastic fracture methods. These methods were evaluated by comparing the analytical predictions with experimental data. The results, using 44 pipe experiments from this and other programs, showed that the SC.TNP1 and DPZP analyses were the most accurate in predicting maximum load. New Z-factors were developed using these methods. These are being considered for updating the ASME Section XI criteria.

  8. Fracture behavior of short circumferentially surface-cracked pipe

    International Nuclear Information System (INIS)

    This topical report summarizes the work performed for the Nuclear Regulatory Comniission's (NRC) research program entitled ''Short Cracks in Piping and Piping Welds'' that specifically focuses on pipes with short, circumferential surface cracks. The following details are provided in this report: (i) material property deteminations, (ii) pipe fracture experiments, (iii) development, modification and validation of fracture analysis methods, and (iv) impact of this work on the ASME Section XI Flaw Evaluation Procedures. The material properties developed and used in the analysis of the experiments are included in this report and have been implemented into the NRC's PIFRAC database. Six full-scale pipe experiments were conducted during this program. The analyses methods reported here fall into three categories (i) limit-load approaches, (ii) design criteria, and (iii) elastic-plastic fracture methods. These methods were evaluated by comparing the analytical predictions with experimental data. The results, using 44 pipe experiments from this and other programs, showed that the SC.TNP1 and DPZP analyses were the most accurate in predicting maximum load. New Z-factors were developed using these methods. These are being considered for updating the ASME Section XI criteria

  9. Fracture Toughness Derived from Small Circumferentially Cracked Bars

    International Nuclear Information System (INIS)

    Small circumferentially Cracked Round Bars (CRB) are used to derive the fracture toughness of reactor pressure vessel steels. This cylindrical geometry is of practical interest for the nuclear industry as it requires only a small amount of irradiated material and as it is easy to test on a tensile machine. This paper describes an experimental procedure to obtain fracture toughness measurements from CRB with a diameter of 10 mm. Emphasis is on crack growth monitoring during rotating bending fatigue precracking, on the formulae used to analyse the load displacement trace of a fracture toughness test and on the correction to be applied to take the loss of constraint into account. Experiments show that the method has the potential to derive fracture toughness values from the lower shelf to the lower transition region. Finite element analysis shows that the constraint of this geometry is generally lower than for bend specimens but is higher at higher load levels, allowing comparison with toughness data valid according to prevailing standards

  10. Exoscope Update: Automated Laser Welding Of Circumferential Tissue Anastomoses

    Science.gov (United States)

    Sauer, Jude S.; McGuire, Kevin P.; Hinshaw, J. Raymond

    1989-09-01

    The speed, accuracy and efficiency of using laser energy to fuse together or weld living tissue makes laser tissue welding one of the most exciting areas of medical research today. Numerous investigators using animal models and several surgeons conducting clinical studies have demonstrated many promising potential applications of laser tissue welding. Accurate tissue positioning and well controlled delivery of laser energy during laser welding are essential for consistently successful laser tissue repairs. Many surgical procedures involve the creation of functional anastomoses, which are patent connections between hollow, tubular tissue structures, like bowel, blood vessels or fallopian tubes. We are developing the Exoscope SystemTM to automate and simplify the production of laser welded end-to-end and end-to-side anastomoses. Any laser light that can be passed through an optical fiber can be used in this system. The Exoscope SystemTM employs a fiber optic Exoscope Device,TM which provides for the precise placement of laser energy onto the abutted tissue seam, and a biocompatible, dissolvable intraluminal PolySurgeTM stent, which holds the tissue in circumferential apposition during lasing. The feasibility of employing the Exoscope SystemTM technique for the construction of rabbit small bowel anastomoses was successfully demonstrated in a Phase I study comparing 30 Exoscope SystemTM laser welded anastomoses to 30 conventional sutured anastomoses.

  11. MYOCARDIAL DEFORMATION AND COMPLETE LEFT BUNDLE BRANCH BLOCK

    OpenAIRE

    2015-01-01

    Tissue Doppler imaging is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular systolic and diastolic function. Over the last 10 years, myocardial deformation imaging has become possible initially with tissue Doppler , and more recently with myocardial speckle-tracking using 2D echocardiography. Unlike simple tissue velocity measurements, deformation measurements are specific for the region of interest. Strain rate or strain measurements have been used a...

  12. Subclinical Cardiac Dysfunction Detected by Strain Imaging During Breast Irradiation With Persistent Changes 6 Weeks After Treatment

    International Nuclear Information System (INIS)

    Purpose: To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT). Methods and Materials: Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined. Results: Left ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) −20.44 ± 2.66 baseline vs −18.60 ± 2.70* during RT vs −18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s−1) −1.19 ± 0.21 vs −1.06 ± 0.18* vs −1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s−1) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s−1) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031). Conclusions: Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed

  13. Subclinical Cardiac Dysfunction Detected by Strain Imaging During Breast Irradiation With Persistent Changes 6 Weeks After Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Queenie [University of New South Wales, Sydney, NSW (Australia); Liverpool Hospital, Sydney, NSW (Australia); Hee, Leia; Batumalai, Vikneswary [University of New South Wales, Sydney, NSW (Australia); Liverpool Hospital, Sydney, NSW (Australia); Ingham Institute of Applied Medical Research, Liverpool, NSW (Australia); Allman, Christine [Liverpool Hospital, Sydney, NSW (Australia); MacDonald, Peter [University of New South Wales, Sydney, NSW (Australia); St. Vincent' s Hospital, Sydney, NSW (Australia); Delaney, Geoff P. [University of New South Wales, Sydney, NSW (Australia); Liverpool Hospital, Sydney, NSW (Australia); Ingham Institute of Applied Medical Research, Liverpool, NSW (Australia); Lonergan, Denise [Liverpool Hospital, Sydney, NSW (Australia); Ingham Institute of Applied Medical Research, Liverpool, NSW (Australia); Thomas, Liza, E-mail: l.thomas@unsw.edu.au [University of New South Wales, Sydney, NSW (Australia); Liverpool Hospital, Sydney, NSW (Australia)

    2015-06-01

    Purpose: To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT). Methods and Materials: Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined. Results: Left ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) −20.44 ± 2.66 baseline vs −18.60 ± 2.70* during RT vs −18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s{sup −1}) −1.19 ± 0.21 vs −1.06 ± 0.18* vs −1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s{sup −1}) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s{sup −1}) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031). Conclusions: Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed.

  14. A numerical investigation of constraint effects in circumferentially cracked pipes and fracture specimens including ductile tearing

    International Nuclear Information System (INIS)

    This work addresses a two-parameter description of crack-tip fields in bend and tensile fracture specimens incorporating the evolution of near-tip stresses following stable crack growth with increased values of the crack driving force as characterized by J. The primary objective of this study is twofold. First, the present investigation broadens current understanding on the role of constraint and test conditions in defect assessment procedures for pipeline girth welds using SE(T) and SE(B) specimens. Second, the work addresses the potential coupled effects of geometry and ductile tearing on crack-tip constraint as characterized by the J−Q theory which enables more accurate correlations of crack growth resistance behavior in conventional fracture specimens. Plane-strain and 3-D finite element computations including stationary and growth analyses are conducted for 3P SE(B) and clamped SE(T) specimens having different notch depth (a) to specimen width (W) ratio in the range 0.1 ≤ a/W ≤ 0.5. Additional 3-D finite element analyses are also performed for circumferentially cracked pipes with a surface flaw having different crack depth (a) over pipe wall thickness (t) ratios and fixed crack length. A computational cell methodology to model Mode I crack extension in ductile materials is utilized to describe the evolution of J with the accompanying evolving near-tip opening stresses. Laboratory testing of an API 5L X70 steel at room temperature using standard, deeply cracked C(T) specimens is used to measure the crack growth resistance curve for the material and to calibrate the key cell parameter defined by the initial void fraction, f0. A key result emerging from this study is that shallow crack SE(B) specimens can accurately and conservately produce crack growth resistance curves that describe well the measuring toughness capacity of circumferentially cracked pipes under remote bending. The present results provide additional understanding of the effects of

  15. Classification of myocardial infarction

    DEFF Research Database (Denmark)

    Saaby, Lotte; Poulsen, Tina Svenstrup; Hosbond, Susanne Elisabeth;

    2013-01-01

    The classification of myocardial infarction into 5 types was introduced in 2007 as an important component of the universal definition. In contrast to the plaque rupture-related type 1 myocardial infarction, type 2 myocardial infarction is considered to be caused by an imbalance between demand and...

  16. Transient myocardial ischemia after myocardial infarction

    DEFF Research Database (Denmark)

    Mickley, H

    1995-01-01

    Ambulatory ST-segment monitoring is a relatively new device in the evaluation of myocardial ischemia. The method is unique in allowing us to continuously examine the patient over an extended period of time in a changing environmental milieu. In survivors of acute myocardial infarction the...... prevalence of ambulatory or transient myocardial ischemia is lower than in patients with chronic, stable coronary artery disease. A greater proportion of ischemic episodes, however, are silent than in other subgroups with ischemic heart disease. Early after the infarction, transient myocardial ischemia...... exhibits a circadian variation with a peak activity occurring in the late evening hours. Patients with non-Q wave infarction have more transient myocardial ischemia, whereas thrombolytic therapy seems to result in less residual ischemia. Exercise testing is more sensitive than ambulatory monitoring in the...

  17. Acute myocardial infarct imaging

    International Nuclear Information System (INIS)

    A brief review is presented of radiopharmaceuticals used for imaging acute myocardial infarction and instrumentation using the rectilinear scanner and the scintillation camera. Clinical experience indicates that myocardial imaging with /sup 99 m/Tc pyrophosphate is a useful adjunct to the electrocardiogram and serum enzyme activity in managing patients with myocardial infarction. The technique allows rapid diagnosis, accurate localization, and an estimate of the size of acute infarcts. It can also be used to document infarct extension and in association with myocardial perfusion imaging can help differentiate fresh from old myocardial infarction

  18. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects.

    LENUS (Irish Health Repository)

    Mohamed, Seif

    2010-05-01

    This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite with that around Nanotite implants.

  19. Circumferential Propagation of Tip Leakage Flow Unsteadiness for a Low-Speed Axial Compressor

    Institute of Scientific and Technical Information of China (English)

    Shaojuan Geng; Feng Lin; Jingyi Chen; Hongwu Zhang; Lei He

    2009-01-01

    ase shift propagating at about half of rotor rotation speed. Features of the short and long length-scale circum-ferential waves are similar to those of rotating instability and modal wave, respectively.

  20. New syndrome of congenital circumferential skin folds associated with multiple congenital anomalies.

    Science.gov (United States)

    Basel-Vanagaite, Lina; Sprecher, Eli; Gat, Andrea; Merlob, Paul; Albin-Kaplanski, Adi; Konen, Osnat; Solomon, Benjamin D; Muenke, Maximilian; Grzeschik, Karl-H; Sirota, Lea

    2012-01-01

    Congenital circumferential skin folds can be found in individuals with no additional defects, as well as in patients with multiple congenital anomalies and developmental abnormalities. Current data point to etiological heterogeneity of syndromic cases. We describe a 7-month-old girl with a novel combination of symmetrical congenital circumferential skin folds, dysmorphic features, and multiple congenital abnormalities. Examination of the patient revealed symmetrical congenital circumferential skin folds and dysmorphic features, as well as multiple congenital anomalies including nasal pyriform aperture stenosis, ventricular septal defect, absent spleen, camptodactyly, and severe psychomotor retardation. Skin biopsy demonstrated subcutaneous fat extending into the superficial and deep reticular dermis. Sequencing of the CDON, SHH, ZIC2, SIX3, and TGIF genes (associated with holoprosencephaly) did not disclose pathogenic alterations. Extensive review of previously described cases of syndromic congenital circumferential skin folds did not reveal a similar combination of clinical and histopathological findings. PMID:21995818

  1. ISSLS prize winner: cost-effectiveness of two forms of circumferential lumbar fusion

    DEFF Research Database (Denmark)

    Freeman, Brian J C; Steele, Nicholas A; Sach, Tracey H;

    2007-01-01

    STUDY DESIGN: Economic evaluation alongside a prospective, randomized controlled trial from a secondary care National Health Service (NHS) perspective. OBJECTIVE: To determine the cost-effectiveness of titanium cages (TC) compared with femoral ring allografts (FRA) in circumferential lumbar spina...

  2. Variation in circumferential resection margin: Reporting and involvement in the South-Netherlands

    NARCIS (Netherlands)

    Homan, J.; Bokkerink, G.M.J.; Aarts, M.J.; Lemmens, V.E.; Lijnschoten, G. van; Rutten, H.J.; Wijsman, J.H.; Nagtegaal, I.D.; Wilt, J.H.W. de

    2015-01-01

    BACKGROUND: Since the introduction of total mesorectal surgery the outcome of rectal cancer patients has improved significantly. Involvement of the circumferential resection margin (CRM) is an important predictor of increased local recurrence, distant metastases and decreased overall survival. Abdom

  3. Reduced Circumferential Resection Margin Involvement in Rectal Cancer Surgery: Results of the Dutch Surgical Colorectal Audit

    NARCIS (Netherlands)

    Gietelink, L.; Wouters, M.W.; Tanis, P.J.; Deken, M.M.; Berge, M.G. Ten; Tollenaar, R.A.; Krieken, J.H.J.M. van; Noo, M.E. de

    2015-01-01

    BACKGROUND: The circumferential resection margin (CRM) is a significant prognostic factor for local recurrence, distant metastasis, and survival after rectal cancer surgery. Therefore, availability of this parameter is essential. Although the Dutch total mesorectal excision trial raised awareness ab

  4. Effect of strength matching on the reliability of welded pipe with circumferential surface crack

    Institute of Scientific and Technical Information of China (English)

    何柏林; 于影霞; 霍立兴; 张玉凤

    2004-01-01

    For different strength matching, the reliability index and failure probability of welded pressure pipe with circumferential surface crack were calculated using three dimensional stochastic finite element method. This method has overcome the shortcomings of conservative results in safety assessment with deterministic fracture mechanics method. The effects of external moment and the depth of the circumferential surface crack (a) on the reliability of pressure pipe were also calculated and discussed. The calculation results indicate that the strength matching has certain effect on the reliability of the welded pressure pipe with circumferential surface crack. The failure probability of welded pressure pipe with high strength matching is lower than that with low strength matching at the same conditions. The effects of strength matching on the failure probability and reliability index increased by adding external moment (M) and the depth of the circumferential surface crack (a).

  5. Soft Sensor for Oxide Scales on the Steam Side of Superheater Tubes under Uneven Circumferential Load

    OpenAIRE

    Qing Wei Li; Gui Huan Yao

    2015-01-01

    A soft sensor for oxide scales on the steam side of superheater tubes of utility boiler under uneven circumferential loading is proposed for the first time. First finite volume method is employed to simulate oxide scales growth temperature on the steam side of superheater tube. Then appropriate time and spatial intervals are selected to calculate oxide scales thickness along the circumferential direction. On the basis of the oxide scale thickness, the stress of oxide scales is calculated by t...

  6. Steady and Unsteady Flow Effects of Circumferential Grooves Casing Treatment in a Transonic Compressor Rotor

    Science.gov (United States)

    Hah, Chunill

    2011-01-01

    The current paper reports on an investigation of steady and unsteady flow effects of circumferential grooves casing treatment in a transonic compressor rotor. Circumferential grooves casing treatment is used mainly to increase stall margin in axial compressors with a relatively small decrease in aerodynamic efficiency. It is widely believed that flow mechanisms of circumferential grooves casing treatment near stall conditions are not yet well understood even though this treatment has been used widely in real engines. Numerical analysis based on steady Reynolds-averaged Navier-Stokes (RANS) has been the primary tool used to understand flow mechanism for circumferential grooves casing treatment. Although steady RANS explains some flow effects of circumferential grooves casing treatment, it does not calculate all the measured changes in the compressor characteristics. Therefore, design optimization of circumferential grooves with steady RANS has not been very successful. As a compressor operates toward the stall condition, the flow field becomes transient. Major sources of self-generated flow unsteadiness are shock oscillation and interaction between the passage shock and the tip leakage vortex. In the present paper, an unsteady Reynolds-averaged Navier-Stokes (URANS) approach is applied to study the effects of circumferential grooves in a transonic compressor. The results from URANS are compared with the results from RANS and measured data. The current investigation shows that there are significant unsteady flow effects on the performance of the circumferential grooves casing treatment. For the currently investigated rotor, the unsteady effects are of the same magnitude as the steady effects in terms of extending the compressor stall margin.

  7. Risk factors of circumferential resection margin involvement in the patients with extraperitoneal rectal cancer

    OpenAIRE

    Oh, Sung Jin; Shin, Jin Yong

    2012-01-01

    Purpose Currently, circumferential resection margins (CRM) are used as a clinical endpoint in studies on the prognosis of rectal cancer. Although the concept of a circumferential resection margin in extraperitoneal rectal cancer differs from that in intraperitoneal rectal cancer due to differences in anatomical and biologic behaviors, previous reports have provided information on CRM involvement in all types of rectal cancer including intraperitoneal lesions. Therefore, the aim of this study ...

  8. Toward Optimum Configuration of Circumferential Groove Casing Treatment in Transonic Compressor Rotors

    Science.gov (United States)

    Hah, Chunill

    2011-01-01

    The current paper first reviews experimental and numerical investigations to understand flow physics and to develop optimum configurations of circumferential grooves in compressor rotors. Circumferential grooves are used mainly to increase stall margin in axial compressors with small decrease in aerodynamic efficiency. Although circumferential groove casing treatment has been used widely, flow mechanisms of the circumferential grooves at near stall conditions are not well understood yet. Detailed time-dependent flow measurement inside tip gap in a high speed compressor is still a big challenge even though significant advance has been made in non-intrusive flow measurement technique. Therefore numerical approaches have been used to study relevant flow physics. However, optimum design of circumferential grooves to a given compressor with the computational tools is not practical yet. In the present paper, various investigations to study flow physics of circumferential groove casing treatment in axial compressor are reviewed first. Possible missing flow physics are identified and future research efforts for the optimum design are discussed.

  9. Left ventricular twist and circumferential strain in dogs with myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Zois, Nora Elisabeth; Olsen, N. T.; Moesgaard, S. G.;

    2013-01-01

    During the cardiac cycle, the ventricle undergoes a twisting motion because of the oblique orientation of the left ventricular (LV) myofibers. This can be quantified by speckle-tracking echocardiography (STE). In mitral regurgitation (MR) in humans, the short axis deformation has been suggested a...... being pivotal to LV function. Decreased and delayed LV twist has been described in experimental MR, but has not been studied in myxomatous mitral valve disease (MMVD)....

  10. Two-dimensional strain imaging: a new echocardiographic advance with research and clinical applications.

    Science.gov (United States)

    Artis, N J; Oxborough, D L; Williams, G; Pepper, C B; Tan, L B

    2008-01-24

    Over the past two decades the quest for quantitative evaluation of left ventricular function and regional wall motion has escalated, allowing several aspects of myocardial contractile patterns to be quantified, both during stress echocardiography and in the assessment of dyssynchrony. Most of the literature to date has used Tissue Doppler Imaging (TDI) techniques to assess essentially long-axis function due to the angle dependency of Doppler based techniques. This brief review introduces the early development, validation and potential clinical applications of a new technique of quantifying two-dimensional (radial and circumferential) strains and strain rates through tracking myocardial "speckles". In-vivo and in-vitro validation of this 2D-strain imaging technique has been undertaken and reached a point where it is considered ready for more widespread investigations into clinical utility. One important advantage over TDI techniques is that it is not limited by dependency on the angle of insonation. Several recent studies looking at ventricular function in specific groups of patients have reported practical ability to distinguish the abnormally from the normally contracting regions of ventricular walls. It provides new and complementary quantitative information about ventricular dyssynchrony and regional wall motion abnormalities. More research studies are needed to determine the sensitivity and specificity of the measurements obtained using this technique and define its strengths and limitations. In particular, whether the measured values correlate well with clinical outcomes will need to be established in longitudinal interventional studies. The clinical utilities of this technique over the coming years are likely to expand rapidly. PMID:17477993

  11. Numerical investigation of a centrifugal compressor with circumferential grooves in vane diffuser

    Science.gov (United States)

    Chen, X. F.; Qin, G. L.; Ai, Z. J.

    2015-08-01

    Enhancing stall and surge margin has a great importance for the development of turbo compressors. The application of casing treatment is an effective measure to expand the stall margin and stable operation range. Numerical investigations were conducted to predict the performance of a low flow rate centrifugal compressor with circumferential groove casing treatment in vane diffuser. Numerical cases with different radial location, radial width and axial depth of a circumferential single groove and different numbers of circumferential grooves were carried out to compare the results. The CFD analyses results show that the centrifugal compressor with circumferential grooves in diffuser can extend stable range by about 9% while the efficiency over the whole operating range decreases by 0.2 to 1.7%. The evaluation based on stall margin improvement showed the optimal position for the groove to be located was indicated to exist near the leading edge of the diffuser, and a combination of position, width, depth and numbers of circumferential grooves that will maximize both surge margin range and efficiency.

  12. Effect of aging on the predicted maximum moment-carrying capacity of circumferentially cracked cast stainless steel pipe

    International Nuclear Information System (INIS)

    Cast stainless steel used in LWR primary system components such as valve bodies, pump castings, pipe fittings, and piping is susceptible to thermal embrittlement at reactor operating temperatures, 280-320 C (536-608 F). This process of thermal aging causes an increase in the hardness and ultimate tensile strength of the steel, and at the same time a decrease in toughness. Work at Argonne National Laboratories (ANL) has shown that such thermal embrittlement due to changes in the microstructure can occur during the reactor lifetime of 40 years. The effect of this thermal degradation on the load- carrying capacity of circumferentially cracked piping is the subject of this work. In this study, both lower-bound and typical values of the J-R curves and the tensile properties for CF8M and CF8A cast stainless steels, which have been artificially aged to simulate 4, 8, 16, 32, and 48 years of service at 300 C (572 F), were used to predict the maximum load-carrying capacity of circumferentially cracked pipes. The effect of aging, that is, reduced toughness and increased strength, for different pipe diameters, crack geometries [i.e., through-wall cracks (TWC) and surface cracks (SC)], and crack sizes has been investigated. Since complete stress-strain curve fits as a function of aging were not available at this time, only three analyses methods could be used. The three analyses methods used to estimate the maximum load-carrying capacity of cracked pipes were: (1) a J-estimation scheme for TWC pipes developed by Paris, (2) a Plastic-Zone-Screening Criteria (DPZP) developed at Battelle which is applicable to both TWC and SC pipe, and (3) the R6 Option 1 method developed by CEGB which is also applicable for both TWC and SC pipe

  13. Exercise-induced ST-T changes and severity of myocardial ischemia in single-vessel coronary artery disease

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate how exercise-induced ST-T changes reflect the severity of myocardial ischemia in 66 patients with singlevessel disease (SVD) who underwent stress thallium scans. Quantitative assessment of myocardial ischemia was performed with thallium ischemic score (TIS) derived from circumferential profile analysis. Circumferential profiles of the initial and 4 hr redistribution myocardial image were generated for each of three views (ANT, LAO 45, LAO 70) and TIS was obtained as the average of the area between the initial and 4 hr redistribution profile for each view. In 66 patients with SVD, TIS were compared with coronary angiographic findings. TIS was correlated well with the severity of coronary artery stenosis. In addition, TIS was also correlated well with lung thallium uptake in 46 LAD disease. Therefore, these data proved that TIS was useful for the evaluation of the severity of myocardial ischemia. In 46 LAD disease, TIS, being as the indicator of the severity of myocardial ischemia, was compared precisely with results of stress electrocardiograms to evaluate how exercise-induced ST-T changes reflect the severity of myocardial ischemia. Patients with negative U wave had the highest mean TIS and those with horizontal or down sloping ST depression of 1.0 mm or more had higher mean TIS than those with slow upsloping ST depression of 1.5 mm or more, but there were no significant differences between these groups and those without ST-T change and the mean TIS was not different significantly between V2-6 ST depression group and V2-6, II, III, aVF ST depression group. In conclusion, these results indicated that exercise-induced ST-T changes reflect the severity of myocardial ischemia in some degree but also has a limitation in evaluation of the severity of myocardial ischemia. (author)

  14. Application of induced circumferential current for cracks inspection on pipe string

    Science.gov (United States)

    Yuan, Xin'an; Li, Wei; Yin, Xiaokang; Chen, Guoming; Ge, Jiuhao

    2016-02-01

    Pipe strings (such as drill pipe, tube, pipeline, riser) are critical facilities in oil & gas industry, which are highly susceptible to cracks caused by stress corrosion and fatigue damage. The most common defects are longitudinal and transverse surface cracks on pipe strings in oil & gas industry. Conventional nondestructive testing (NDT) methods are inadequate for these surface cracks on pipe strings. In this paper, a full 360° circumferential current induced by a coaxial excitation coil is present for inspection of longitudinal and transverse surface cracks on pipe strings. The finite element method (FEM) is employed to obtain characteristics signals by analyzing the distorted electromagnetic field above the cracks. The induced circumferential current test system is set up and crack inspection experiments are carried out. The results show that both longitudinal and transverse surface cracks can be detected effectively at one pass scanning on pipe string using the induced circumferential current.

  15. A study on nondestructive evaluation techniques for composite motors cases using circumferential waves

    International Nuclear Information System (INIS)

    For structural integrity evaluation of composite rocket motor cases, acoustic emission (AE) during hydroproof test is currently used. For the suitable performance of this test, it is very important to determine the optimal component of elastic waves to be monitored. In this study, the optimal component of circumferential wave that propagate in the circumferential direction of the composite motor case has been determined experimentally. Then its potential to be served as a robust tool for nondestructive evaluation of composite motor cases was demonstrated by investigating the initial performances for flaw detection and AE source location.

  16. Aerodynamic Inner Workings of Circumferential Grooves in a Transonic Axial Compressor

    Science.gov (United States)

    Hah, Chunill; Mueller, Martin; Schiffer, Heinz-Peter

    2007-01-01

    The current paper reports on investigations of the fundamental flow mechanisms of circumferential grooves applied to a transonic axial compressor. Experimental results show that the compressor stall margin is significantly improved with the current set of circumferential grooves. The primary focus of the current investigation is to advance understanding of basic flow mechanics behind the observed improvement of stall margin. Experimental data and numerical simulations of a circumferential groove were analyzed in detail to unlock the inner workings of the circumferential grooves in the current transonic compressor rotor. A short length scale stall inception occurs when a large flow blockage is built on the pressure side of the blade near the leading edge and incoming flow spills over to the adjacent blade passage due to this blockage. The current study reveals that a large portion of this blockage is created by the tip clearance flow originating from 20% to 50% chord of the blade from the leading edge. Tip clearance flows originating from the leading edge up to 20% chord form a tip clearance core vortex and this tip clearance core vortex travels radially inward. The tip clearance flows originating from 20% to 50% chord travels over this tip clearance core vortex and reaches to the pressure side. This part of tip clearance flow is of low momentum as it is coming from the casing boundary layer and the blade suction surface boundary layer. The circumferential grooves disturb this part of the tip clearance flow close to the casing. Consequently the buildup of the induced vortex and the blockage near the pressure side of the passage is reduced. This is the main mechanism of the circumferential grooves that delays the formation of blockage near the pressure side of the passage and delays the onset of short length scale stall inception. The primary effect of the circumferential grooves is preventing local blockage near the pressure side of the blade leading edge that

  17. Molecular Modeling of the Axial and Circumferential Elastic Moduli of Tubulin

    OpenAIRE

    Zeiger, A. S.; Layton, B. E.

    2008-01-01

    Microtubules play a number of important mechanical roles in almost all cell types in nearly all major phylogenetic trees. We have used a molecular mechanics approach to perform tensile tests on individual tubulin monomers and determined values for the axial and circumferential moduli for all currently known complete sequences. The axial elastic moduli, in vacuo, were found to be 1.25 GPa and 1.34 GPa for α- and β-bovine tubulin monomers. In the circumferential direction, these moduli were 378...

  18. Acute myocardial infarction:myocardial salvage assessment

    Institute of Scientific and Technical Information of China (English)

    NSENGIYUMVA Pierre; CHEN Li-juan; MA Gen-shan

    2015-01-01

    Primary coronary revascularization by means of percutaneous coronary intervention ( PCI) is a highly ef-fective treatment of acute myocardial infarction re-establishing coronary perfusion and stopping the ongoing necrosis in the dependent myocardium .Single-photon emission computed tomography ( SPECT) is the most widely used mo-dality assessing myocardial salvage as the difference between the acute perfusion defect before intervention and the remaining scar size measured in a second scan several days after the event .SPECT allows quantification of area at risk( AAR) and final infarct size ( FIS) by tracer injection prior to revascularization and after 1 month, respective-ly.SPECT provides the most validated measure of myocardial salvage and has been utilized in multiple randomized clinical trials.However, SPECT is logistically challenging , expensive, and includes radiation exposure .More re-cently, a large number of studies have suggested that cardiac magnetic resonance ( CMR) can determine salvage in a single examination by combining measures of myocardial oedema in the AAR exposed to ischaemia reperfusion with FIS quantification by late gadolinium enhancement .

  19. Determination of the minimum number exposures in radiographic examination of circumferential welds

    International Nuclear Information System (INIS)

    Certain specifications require that, in the radiography of circumferential welds, the penetrated thickness at the side of the beam should not exceed the wall thickness by more than a given percentage. A mathematical solution is presented, which shows the minimum number of exposures in accurate and easy-to-read diagrams suitable for use by field radiographers. (orig.)

  20. 46 CFR 52.05-45 - Circumferential joints in pipes, tubes and headers (modifies PW-41).

    Science.gov (United States)

    2010-10-01

    ..., tubes and headers shall be as required by PW-41 of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01-1) except as noted otherwise in this section. (b) (Modifies PW-41.1) Circumferential welded joints in pipes, tubes, and headers of pipe material must be nondestructively examined...

  1. Modification of the ASME code z-factor for circumferential surface crack in nuclear ferritic pipings

    International Nuclear Information System (INIS)

    The purpose of this paper is to modify the ASME Code Z-Factor, which is used in the evaluation of circumferential surface crack in nuclear ferritic pipings. The ASME Code Z-Factor is a load multiplier to compensate plastic load with elasto-plastic load. The current ASME Code Z-Factor underestimates pipe maximum load. In this study, the original SC. TNP method is modified first because the original SC. TNP method has a problem that the maximum allowable load predicted from the original SC. TNP method is slightly higher than that measured from the experiment. Then the new Z-Factor is developed using the modified SC. TNP method. The desirability of both the modified SC. TNP method and the new Z-Factor is examined using the experimental results for the circumferential surface crack in pipings. The results show that (1) the modified SC. TNP method is good for predicting the circumferential surface crack behavior in pipings, and (2) the Z-Factor obtained from the modified SC. TNP method well predicts the behavior of circumferential surface crack in ferritic pipings. 30 refs., 13 figs., 4 tabs. (author)

  2. A method for measuring mean circumferential fiber shortening rate from gated blood pool scans

    International Nuclear Information System (INIS)

    Ejection fraction and ejection rate are easily obtained from gated cardiac images, but no method is available for calculating mean circumferential fiber shortening rate. We assumed that the cube root of left ventricular end-diastolic volume or counts is proportional to the minor axis of the left ventricle at end-diastole or end-systole. Mean circumferential fiber shortening rate is then equal to the [cube root of the end-diastolic volume (count) minus cube root of end-systolic volume (count)] divided by [cube root of end-diastolic volume (count) multiplied by the ejection time]. In 250 contrast ventriculograms, the standard mean circumferential fiber shortening rate (MCFSR) and that derived by the cube root method correlated well (r = 0.94). The mean value of MCFSR (0.85 +- 0.35) was greater than the cube root value (0.75 +- 0.35) (P < 0.001). The regression equation was y = 0.86x + 0.02. Similar correlations were obtained from gated radionuclide images using a semiautomated program (r = 0.93) in 24 subjects or completely automated program (r = 0.85) in 28 patients. The regression equation between MCFSR and that derived from the cube root of counts for the semiautomated program was y = 0.82x + 0.04 and for the automated program was y = 0.84x + 0.004. Similar correlations, slopes, and intercepts were seen using circumferential fractional shortening for angiographic data when correlated with both the semiautomated and automated gated blood pool scan programs. These data indicate that MCFSR and circumferential fractional shortening may be obtained from gated blood pool images using cube root estimates of end-diastolic and end-systolic radii with a high degree of correlation with the standard contrast ventriculographic technique. (orig.)

  3. Crack initiation under generalized plane strain conditions

    International Nuclear Information System (INIS)

    A method for estimating the decrease in crack-initiation toughness, from a reference plane strain value, due to positive straining along the crack front of a circumferential flaw in a reactor pressure vessel is presented in this study. This method relates crack initiation under generalized plane strain conditions with material failure at points within a distance of a few crack-tip-opening displacements ahead of a crack front, and involves the formulation of a micromechanical crack-initiation model. While this study is intended to address concerns regarding the effects of positive out-of- plane straining on ductile crack initiation, the approach adopted in this work can be extended in a straightforward fashion to examine conditions of macroscopic cleavage crack initiation. Provided single- parameter dominance of near-tip fields exists in the flawed structure, results from this study could be used to examine the appropriateness of applying plane strain fracture toughness to the evaluation of circumferential flaws, in particular to those in ring-forged vessels which have no longitudinal welds. In addition, results from this study could also be applied toward the analysis of the effects of thermal streaming on the fracture resistance of circumferentially oriented flaws in a pressure vessel. 37 refs., 8 figs., 1 tab

  4. Impaired myocardial function does not explain reduced left ventricular filling and stroke volume at rest or during exercise at high altitude.

    Science.gov (United States)

    Stembridge, Mike; Ainslie, Philip N; Hughes, Michael G; Stöhr, Eric J; Cotter, James D; Tymko, Michael M; Day, Trevor A; Bakker, Akke; Shave, Rob

    2015-11-15

    Impaired myocardial systolic contraction and diastolic relaxation have been suggested as possible mechanisms contributing to the decreased stroke volume (SV) observed at high altitude (HA). To determine whether intrinsic myocardial performance is a limiting factor in the generation of SV at HA, we assessed left ventricular (LV) systolic and diastolic mechanics and volumes in 10 healthy participants (aged 32 ± 7; mean ± SD) at rest and during exercise at sea level (SL; 344 m) and after 10 days at 5,050 m. In contrast to SL, LV end-diastolic volume was ∼19% lower at rest (P = 0.004) and did not increase during exercise despite a greater untwisting velocity. Furthermore, resting SV was lower at HA (∼17%; 60 ± 10 vs. 70 ± 8 ml) despite higher LV twist (43%), apical rotation (115%), and circumferential strain (17%). With exercise at HA, the increase in SV was limited (12 vs. 22 ml at SL), and LV apical rotation failed to augment. For the first time, we have demonstrated that EDV does not increase upon exercise at high altitude despite enhanced in vivo diastolic relaxation. The increase in LV mechanics at rest may represent a mechanism by which SV is defended in the presence of a reduced EDV. However, likely because of the higher LV mechanics at rest, no further increase was observed up to 50% peak power. Consequently, although hypoxia does not suppress systolic function per se, the capacity to increase SV through greater deformation during submaximal exercise at HA is restricted. PMID:25749445

  5. Left ventricular strain and strain rate by 2D speckle tracking in chronic thromboembolic pulmonary hypertension before and after pulmonary thromboendarterectomy

    Directory of Open Access Journals (Sweden)

    Waltman Thomas J

    2010-09-01

    Full Text Available Abstract Background Echocardiographic evaluation of left ventricular (LV strain and strain rate (SR by 2D speckle tracking may be useful tools to assess chronic thromboembolic pulmonary hypertension (CTEPH severity as well as response to successful pulmonary thromboendarterectomy (PTE. Methods We evaluated 30 patients with CTEPH before and after PTE using 2D speckle tracking measurements of LV radial and circumferential strain and SR in the short axis, and correlated the data with right heart catheterization (RHC. Results PTE resulted in a decrease in mean PA pressure (44 ± 15 to 29 ± 9 mmHg, decrease in PVR (950 ± 550 to 31 ± 160 [dyne-sec]/cm5, and an increase in cardiac output (3.9 ± 1.0 to 5.0 ± 1.0 L/min, p change in circumferential strain and change in posterior wall radial strain correlated moderately well with changes in PVR, mean PA pressure and cardiac output (r = 0.69, 0.76, and 0.51 for circumferential strain [p Conclusions LV circumferential and posterior wall radial strain change after relief of pulmonary arterial obstruction in patients with CTEPH, and these improvements occur rapidly. These changes in LV strain may reflect effects from improved LV diastolic filling, and may be useful non-invasive markers of successful PTE.

  6. Analysis of dispersion characteristics of circumferential guided waves and detection of axial cracks in pipe

    International Nuclear Information System (INIS)

    A circumferential guided wave method was developed to detect the axial crack on the but feeder pipe. Dispersion curves of circumferential guided waves were calculated as a function of curvature of the pipe. In the case of thin plate, i. e. infinite curvature, as the frequency increases, the S0 and A0 become to be coincided and eventually Rayleigh wave mode. In the case of pipe, however, as the curvature increases, the lowest modes do not coincide even in the high frequencies. Based on the analysis, a rocking technique using angle beam transducer was applied to detect axial defect in the bent region of PHWR feeder pipe. After review of the experimental data on the artificial notches, the vibration modes of each signal were identified. It was found that the notches with the depth of 10% of wall thickness be detected with the method.

  7. Low cycle fatigue of pressurized pipes with circumferential flaws under cyclic bending moment

    International Nuclear Information System (INIS)

    Pipes of 706 mm inner diameter, 47 mm wall thickness and about 5,000 mm in length were provided with circumferential surface cracks and loaded by internal pressure of 15 MPa whilst being simultaneously subjected to an alternating external bending moment. Usually a load ratio R of -1 (Mmin/Mmax), in one case R = 0.1, was applied. The pipes were fabricated of two types of ferritic steel: one, grade 20 MnMoNi 5 5, with a high upper shelf impact energy of about 200 J and one, MnMoNiV-special melt, with a low upper shelf impact energy of about 60 J. Deformation and crack growth in the wall thickness and circumferential direction were determined and compared with calculated values. 9 refs., 13 figs

  8. A "watch window" technique for monitoring buried free jejunum flaps during circumferential pharyngolaryngectomy reconstruction.

    Science.gov (United States)

    Li, Quan; Zhang, Xin-Rui; Liu, Xue-Kui; Zhang, Zhi-Gang; Liu, Wei-Wei; Li, Hao; Guo, Zhu-Ming

    2012-07-01

    The free jejunum flap approach is the optimal option for circumferential pharyngolaryngectomy reconstruction. In this study, we designed a "watch window" for monitoring buried free jejunum flaps, thereby allowing us to assess graft viability. From 2007 to 2011, 14 patients with hypopharyngeal cancer underwent circumferential pharyngolaryngectomy that was reconstructed using a free jejunum flap at the Sun Yat-sen University Cancer Centre. During the closing of the neck incision, a "watch window" was designed for postoperative monitoring. Two patients experienced thrombosis of the pedicle. One was detected early and successfully rescued by removal of the thrombosis, the other one managed with a second free jejunum flap. The success rate of the buried flaps was 92.9%. No pharyngocutaneous fistulas or strictures occurred. All patients eventually resumed oral feeding and swallowing. The "watch window" technique for monitoring buried free jejunum flaps is simple, reliable and useful for finding vascular problems. Level of evidence Case series. PMID:22116384

  9. Circumferential-wave phase velocities for empty, fluid-immersed spherical metal shells

    DEFF Research Database (Denmark)

    Überall, Herbert; Ahyi, A. C.; Raju, P. K.;

    2002-01-01

    In earlier studies of acoustic scattering resonances and of the dispersive phase velocities of surface waves that generate them [see, e.g., Talmant et al., J. Acoust. Soc. Am. 86, 278–289 (1989) for spherical aluminum shells] we have demonstrated the effectiveness and accuracy of obtaining phase...... results with those calculated from three-dimensional elasticity theory whenever the latter are available. The present investigation is based on the mentioned resonance frequency/elasticity theory connection, and we obtain comparative circumferential-wave dispersion-curve results for water......-loaded, evacuated spherical metal shells of aluminum, stainless steel, and tungsten carbide. In particular, the characteristic upturn of the dispersion curves of low-order shell-borne circumferential waves (A or A0 waves) which takes place on spherical shells when the frequency tends towards very low values, is...

  10. Crack resistance of austenitic pipes with circumferential through-wall cracks

    International Nuclear Information System (INIS)

    For monotonously increasing load the correct evaluation of the crack resistance properties of a structure is essential for safety analyses. Considerable attention has been given to the through-wall case, since this is generally believed to be the controlling case with regard to complete pipe failure. The maximum load conditions for circumferential crack growth in pipes under displacement-controlled loadings has been determined. The need for crack resistance curves, measured on circumferentially through-wall cracked straight pipes of austenitic stainless steel 316L under bending, is emphasized by the limitation in the data range on small specimens and by the differences in the procedures. To answer open questions and to improve calculational methods a joint fracture mechanics program is being performed by Electricite de France, Novatome and Siemens-Interatom. The working program contains experimental and theoretical investigations on the applicability of small-specimen data to real structures. 10 refs., 10 figs., 4 tabs

  11. Is Circumferential Minimally Invasive Surgery Effective in the Treatment of Moderate Adult Idiopathic Scoliosis?

    OpenAIRE

    Anand, Neel; Baron, Eli M.; Khandehroo, Babak

    2014-01-01

    Background Outcomes for minimally invasive scoliosis correction surgery have been reported for mild adult scoliosis. Larger curves historically have been treated with open surgical procedures including facet resections or posterior column osteotomies, which have been associated with high-volume blood loss. Further, minimally invasive techniques have been largely reported in the setting of degenerative scoliosis. Questions/purposes We describe the effects of circumferential minimally invasive ...

  12. Circumferential mucosal dissection and esophageal perforation in a patient with eosinophilic esophagitis

    OpenAIRE

    Liguori, Gennaro; Cortale, Maurizio; Cimino, Fabrizio; Sozzi, Michele

    2008-01-01

    A young man with a previous history of episodes of mild solid food dysphagia was admitted with a total dysphagia. The esophagogastroduodenoscopy (EGDS) showed an extensive disruption of mucosal layer with a cul-de-sac in the lower part of the esophagus. Soon after the procedure, the patient suffered from an acute chest pain and subsequent CT scan demonstrated an intramural circumferential dissection of thoracic esophagus, and a mediastinal emphysema. An emergency right thoracotomy was perform...

  13. Heroin Abuse and Myocardial Infarction

    OpenAIRE

    Tatli, Ersan; Aktoz, Meryem

    2010-01-01

    Information concerning acute myocardial infarction after heroin usage is limited and the actual mechanism of heroin-induced myocardial infarction is not well known. Only one report has been described noting the association between usage heroin and acute myocardial infarction in a young man with normal coronary arteries. We also reported a patient with normal coronary arteries and acute myocardial infarction after heroin abuse. Eroin kullanımı sonrası akut miyokard inf...

  14. Exact solutions for the vibration of circumferentially stepped orthotropic circular cylindrical shells

    Science.gov (United States)

    Khalifa, Ahmed Mousa

    2011-11-01

    The combination of Flügge's shell theory, the transfer matrix approach and the Romberg integration method are used to investigate the free vibration behaviour of stepped orthotropic cylindrical shells. The hoop step on the shell surface is described by a reduced thickness over part of its circumference. Modal displacements of the shell can be described by trigonometric functions and Fourier's approach is used to separate the variables. The vibration equations of the shell are reduced to eight first-order differential equations in the circumferential coordinate, and by using the transfer matrix of the shell, these equations can be written in a matrix differential equation. The transfer matrix is derived from the non-linear differential equations of the cylindrical shells by introducing the trigonometric functions in the longitudinal direction and applying the numerical integration in the circumferential direction. The proposed model is used to get the vibration frequencies and the corresponding mode shapes for symmetrical and antisymmetrical type-modes. Computed results indicate the sensitivity of the frequency parameters and the bending deformations to the geometry of stepped shell, and also to the axial and circumferential rigidities of the shell.

  15. Soft Sensor for Oxide Scales on the Steam Side of Superheater Tubes under Uneven Circumferential Load

    Directory of Open Access Journals (Sweden)

    Qing Wei Li

    2015-01-01

    Full Text Available A soft sensor for oxide scales on the steam side of superheater tubes of utility boiler under uneven circumferential loading is proposed for the first time. First finite volume method is employed to simulate oxide scales growth temperature on the steam side of superheater tube. Then appropriate time and spatial intervals are selected to calculate oxide scales thickness along the circumferential direction. On the basis of the oxide scale thickness, the stress of oxide scales is calculated by the finite element method. At last, the oxide scale thickness and stress sensors are established on support vector machine (SMV optimized by particle swarm optimization (PSO with time and circumferential angles as inputs and oxide scale thickness and stress as outputs. Temperature and stress calculation methods are validated by the operation data and experimental data, respectively. The soft sensor is applied to the superheater tubes of some power plant. Results show that the soft sensor can give enough accurate results for oxide scale thickness and stress in reasonable time. The forecasting model provides a convenient way for the research of the oxide scale failure.

  16. Cardiac mechanics and ventricular twist by three-dimensional strain analysis in relation to B-type natriuretic peptide as a clinical prognosticator for heart failure patients.

    Directory of Open Access Journals (Sweden)

    Sheng-Nan Chang

    Full Text Available BACKGROUND: Three dimensional (3D echocardiography-derived measurements of myocardial deformation and twist have recently advanced as novel clinical tools. However, with the exception of left ventricular ejection fraction and mass quantifications in hypertension and heart failure populations, the prognostic value of such imaging techniques remains largely unexplored. METHODS: We studied 200 subjects (mean age: 60.2±16 years, 54% female, female n = 107 with known hypertension (n = 51, diastolic heart failure (n = 61, or systolic heart failure (n = 30, recruited from heart failure outpatient clinics. Fifty-eight healthy volunteers were used as a control group. All participants underwent 3D-based myocardial deformation and twist analysis (Artida, Toshiba Medical Systems, Tokyo, Japan. We further investigated associations between these measures and brain natriuretic peptide levels and clinical outcomes. RESULTS: The global 3D strain measurements of the healthy, hypertension, diastolic heart failure, and systolic heart failure groups were 28.03%, 24.43%, 19.70%, and 11.95%, respectively (all p<0.001. Global twist measurements were estimated to be 9.49°, 9.77°, 8.32°, and 4.56°, respectively. We observed significant differences regarding 3D-derived longitudinal, radial, and global 3D strains between the different disease categories (p<0.05, even when age, gender, BMI and heart rate were matched. In addition, 3D-derived longitudinal, circumferential, and 3D strains were all highly correlated with brain natriuretic peptide levels (p<0.001. At a mean 567.7 days follow-up (25th-75th IQR: 197-909 days, poorer 3D-derived longitudinal, radial, and global 3D strain measurements remained independently associated with a higher risk of cardiovascular related death or hospitalization due to heart failure, after adjusting for age, gender, and left ventricular ejection fraction (all p<0.05. CONCLUSIONS: 3D-based strain analysis may be a

  17. Measuring myocardial perfusion

    DEFF Research Database (Denmark)

    Qayyum, A A; Kastrup, J

    2015-01-01

    . Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well-known and......-pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD...

  18. Changes in myocardial perfusion due to physical exercise in patients with stable coronary artery disease

    International Nuclear Information System (INIS)

    Percutaneous transluminal coronary angioplasty (PTCA) is one of the main therapy options for patients with coronary artery disease (CAD), resulting in an improvement in myocardial perfusion and exercise capacity. Nevertheless, studies have also demonstrated a positive effect of regular exercise training on myocardial perfusion and maximum exercise capacity. The aim of this study was to evaluate changes in myocardial stress perfusion after 1 year of exercise training in comparison with the effects of PTCA in patients with CAD. In 66 male patients with angiographically confirmed significant coronary artery stenosis in one target vessel, myocardial perfusion scintigraphy was performed at baseline and 12 months after randomisation into either a physical exercise group or a PTCA group. Circumferential count rate profiles in 16 wall segments were classified according to their relative count rate and localisation within or outside the area supplied by the stenosed vessel. Ischaemic segments showed a significant improvement in myocardial count rate within the target area after 12 months in both the PTCA and the training group (PTCA group: from 76.8±4.9% to 86.6±10.9%, p=0.03; training group: from 74.0±7.3% to 83.7±10.8%, p<0.01). Outside the target area only the training group showed a significant improvement (from 77.7±4.4% to 91.7±4.8%, p<0.01). Our data indicate a significant improvement in stress myocardial perfusion in the training group after 12 months. The ischaemia is reduced not only in the target region of the leading stenosis but also in other ischaemic myocardial areas. In contrast, after PTCA stress perfusion improves only in the initially ischaemic parts of the target area. (orig.)

  19. Scalp ulceration from a circumferential head dressing after craniotomy: Case report of an uncommon complication due to human error

    OpenAIRE

    Singhal, Ashutosh; Bray, Peter W.; Bernstein, Mark

    2004-01-01

    The present paper describes a previously unpublished complication of the application of a circumferential head dressing after cranial neuro-surgery. A 34-year-old woman developed a large area of skin necrosis on her forehead from a circumferential head dressing applied after the surgical removal of a colloid cyst. Neurological recovery was excellent but plastic surgical repair of her iatrogenic cosmetic injury was required.

  20. Clinical implication of negative conversion of predicted circumferential resection margin status after preoperative chemoradiotherapy for locally advanced rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nam Kwon [Department of Radiation Oncology, Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of); Kim, Chul Yong, E-mail: kcyro@korea.ac.kr [Department of Radiation Oncology, Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of); Park, Young Je; Yang, Dae Sik; Yoon, Won Sup [Department of Radiation Oncology, Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of); Kim, Seon Hahn; Kim, Jin [Division of Colorectal Surgery, Department of Surgery, Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of)

    2014-02-15

    Objective: To evaluate the prognostic implication of the negative conversion of predicted circumferential resection margin status before surgery in patients with locally advanced rectal cancer with predicted circumferential resection margin involvement. Methods: Thirty-eight patients (28 men, 10 women; median age, 61 years; age range, 39–80 years) with locally advanced rectal cancer with predicted circumferential resection margin involvement who underwent preoperative chemoradiotherapy followed by radical surgery were analyzed. Involvement of the circumferential resection margin was predicted on the basis of pre- and post-chemoradiotherapy magnetic resonance imaging. The primary endpoints were 3-year local recurrence-free survival and overall survival. Results: The median follow-up time was 41.1 months (range, 13.9–85.2 months). The negative conversion rate of predicted circumferential resection margin status after preoperative chemoradiotherapy was 65.8%. Patients who experienced negative conversion of predicted circumferential resection margin status had a significantly higher 3-year local recurrence-free survival rate (100.0% vs. 76.9%; P = 0.013), disease-free survival rate (91.7% vs. 59.3%; P = 0.023), and overall survival rate (96.0% vs. 73.8%; P = 0.016) than those who had persistent circumferential resection margin involvement. Conclusions: The negative conversion of the predicted circumferential resection margin status as predicted by magnetic resonance imaging will assist in individual risk stratification as a predictive factor for treatment response and survival before surgery. These findings may help physicians determine whether to administer more intense adjuvant chemotherapy or change the surgical plan for patients displaying resistance to preoperative chemoradiotherapy.

  1. Myocardial perfusion SPECT imaging in patients with myocardial bridging

    International Nuclear Information System (INIS)

    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)

  2. Posterior-Only Circumferential Decompression and Reconstruction in the Surgical Management of Lumbar Vertebral Osteomyelitis.

    Science.gov (United States)

    Skovrlj, Branko; Guzman, Javier Z; Caridi, John; Cho, Samuel K

    2016-02-01

    Study Design Case report. Objective The purpose of this report is to discuss the surgical management of lumbar vertebral osteomyelitis with a spinal epidural abscess (SEA) and present a single-stage, posterior-only circumferential decompression and reconstruction with instrumentation using an expandable titanium cage and without segmental nerve root sacrifice as an option in the treatment of this disease process. Methods We report a 42-year-old man who presented with 3 days of low back pain and chills who rapidly decompensated with severe sepsis following admission. Magnetic resonance imaging of his lumbosacral spine revealed intramuscular abscesses of the left paraspinal musculature and iliopsoas with SEA and L4 vertebral body involvement. The patient failed maximal medical treatment, which necessitated surgical treatment as a last resort for infectious source control. He underwent a previously undescribed procedure in the setting of SEA: a single-stage, posterior-only approach for circumferential decompression and reconstruction of the L4 vertebral body with posterior segmental instrumented fixation. Results After the surgery, the patient's condition gradually improved; however, he suffered a wound dehiscence necessitating a surgical exploration and deep wound debridement. Six months after the surgery, the patient underwent a revision surgery for adjacent-level pseudarthrosis. At 1-year follow-up, the patient was pain-free and off narcotic pain medication and had returned to full activity. Conclusion This patient is the first reported case of lumbar osteomyelitis with SEA treated surgically with a single-stage, posterior-only circumferential decompression and reconstruction with posterior instrumentation. Although this approach is more technically challenging, it presents another viable option for the treatment of lumbar vertebral osteomyelitis that may reduce the morbidity associated with an anterior approach. PMID:26835214

  3. Fracture Toughness (K1C evaluation for dual phase medium carbon low alloy steels using circumferential notched tensile (CNT specimens

    Directory of Open Access Journals (Sweden)

    Kenneth Kanayo Alaneme

    2011-01-01

    Full Text Available The fracture behavior of dual phase medium carbon low alloy steels produced using two different chemical compositions (A - 0.34C, 0.75Mn, 0.12Cr, 0.13Ni steel and B - 0.3C, 0.97Mn, 0.15Cr steel was investigated using circumferential notched tensile (CNT specimens. Intercritical treatments were performed on samples with composition A by 1 austenitizing at 860 °C for 1 hour cooling in air, then treating at 770 °C for 30 minutes before oil quenching; 2 austenitizing at 860 °C for 1 hour quenching in oil, then treating at 770 °C for 30 minutes before quenching in oil; and 3 austenitizing at 860 °C for 1 hour, super-cooling to 770 °C and then quenching in oil. Samples of composition B were subjected to intercritical treatment at temperatures of 740, 760, and 780 °C for 30 minutes, followed by quenching rapidly in oil. Tensile testing was then performed on specimens without notches and the CNT specimens. It was observed that the dual phase steel produced from procedure (2 yielded a fine distribution of ferrite and martensite which gave the best combination of tensile properties and fracture toughness for composition A while the dual phase structure produced by treating at 760 °C yielded the best combination of tensile properties and fracture toughness for composition B. The fracture toughness results evaluated from the test were found to be valid (in plain strain condition and a high correlation between the fracture toughness and notch tensile strength was observed. The fracture toughness values were also found to be in close agreement with data available in literature.

  4. Investigations on an Axial Flow Fan Stage subjected to Circumferential Inlet Flow Distortion and Swirl

    Institute of Scientific and Technical Information of China (English)

    M.Govardhan; K.Viswanath

    1997-01-01

    The combined effects of swirl and circumferential inlet flow distortion on the flow field of an axial flow fan stage are reported in this paper,The study involves measurements at the inlet of the rotor and exit of the rotor and stator atdesign and off design flow conditions.The study indicated that at the design flow condition,swirl had caused deterioration of the performance in addition to that caused by distortion.Pressure rise imparted in the distortion zone is hogher than in the free zone.The attenuation of distortion is high in the presence of swirl.

  5. Fracture toughness evaluation using circumferential notched tensile specimens by the tensile test and ANSYS software

    International Nuclear Information System (INIS)

    Fracture toughness (KIc ) is the most important parameter that defines mechanical behaviour of the materials using machine design. Since, fracture tests are both difficult and time consuming, the researchers have been investigating for the easier evaluation of KIc for many years. In this work; KIc values have been obtained by using ANSYS software based on the experimental values evaluated in the previous studies. It was shown that there is no significant difference between the experimental ones and the ones obtained by ANSYS. This procedure can provide an important advantage on obtaining of the KIC values. Key words: Fracture toughness (KIc ), circumferential notched tensile specimens, ANSYS

  6. Circumferential skin folds in a child: A case of Michelin tire baby syndrome

    Directory of Open Access Journals (Sweden)

    Palit Aparna

    2007-01-01

    Full Text Available A six-month-old girl who presented with dermatitis was found to have multiple, symmetric, deep, gyrate skin folds involving her trunk and similar circumferential lesions on her extremities since birth. She had a characteristic round face with hypertelorism, depressed nasal bridge, thin, down-turned vermillion border of upper lip and short neck. Skin biopsy demonstrated increased smooth muscle fibers in the deeper dermis. A diagnosis of Michelin tire baby syndrome was made. Clinical features, histopathology, differential diagnosis and prognosis of this rare disorder have been discussed.

  7. Geometric characterization of a circumferential seam by automatic segmentation of digitized radioscopic images

    International Nuclear Information System (INIS)

    The present study deals with the nondestructive control of a circumferential seam by digital radioscopy. A series of images for one complete revolution of the welded component is available. We first resort to a joint approach by simulation and experimentation. This approach allows the detection of the molten zone limits for an initial image. We then develop a segmentation method that permits automatic extraction of the geometric characteristics of the set of images representative of the weld. These measures supply fast and automatic control of the weld quality. Results are shown for real components. (author)

  8. Application of statically indeterminate fracture mechanics, SIFM, to a circumferentially cracked cylinder problem

    International Nuclear Information System (INIS)

    The method of Statically Indeterminate Fracture Mechanics called SIFM is an application of elastic-plastic fracture mechanics to statically indeterminate problems. Application of SIFM has been developed for axially cracked cylinder problems. Its application was modified to a circumferentially cracked cylinder. The component might be loaded by combined transient thermal and mechanical loading. This was applied to simulate pressurized thermal shock, PTS, experiment, NKS-3, carried out by MPA. The predicted result from SIFM shows good agreement with the NKS-3 experimental one. (orig.)

  9. Inner wall inspection of steam generator tubes with circumferential welds using ultrasonic crack detection

    International Nuclear Information System (INIS)

    Cracks in the neighbourhood of circumferential welds at the inside of generator tubes to the weld seam can be detected with an ultrasonic probe system using Rayleigh's surface waves. A reference reflector with about 0.5 mm in depth and 1.5 mm in length is used. The ultrasonic inspection system is using a rotating mirror with two faces which can detect cracks on both sides of the weld and which can clearly separate crown or root indications from real defects. The signal-to-noise ratio is better than 12 dB. The system and results on tubes with artificial and real test reflectors are described

  10. Inner wall inspection of steam generator tubes with circumferential welds using ultrasonic crack detection

    International Nuclear Information System (INIS)

    Cracks in the neighbourhood of circumferential welds at the inside of generator tubes to the weld seam can be detected with an ultrasonic probe system using Rayleigh's surface waves. A reference reflector with about 0.5 mm in depth and 1.5 mm in length is used. The ultrasonic inspection system is using a rotating mirror with two faces which can detect cracks on both sides of the weld and which can clearly separate crown or root indications from real defects. The signal-to-noise ratio is better than 12 dB. The system and results on tubes with artificial and real test reflectors are described. 8 refs

  11. Acute myocardial infarction related to smoke inhalation and myocardial bridging.

    OpenAIRE

    McCabe, M J; Weston, C. F.; Fraser, A G

    1992-01-01

    A previously healthy 26 year old woman who was exposed to smoke during a house fire developed acute anterior myocardial infarction complicated by ventricular fibrillation. Subsequent left ventriculography confirmed anterior infarction, but coronary arteriography was normal apart from myocardial bridging over a segment of the left anterior descending artery. The development of acute myocardial infarction in this patient suggests that, in the presence of bridging, carbon monoxide inhalation may...

  12. High-resolution three-dimensional 19F-magnetic resonance imaging of rat lung in situ: evaluation of airway strain in the perfluorocarbon-filled lung

    International Nuclear Information System (INIS)

    Perfluorocarbons (PFC) are biologically and chemically inert fluids with high oxygen and CO2 carrying capacities. Their use as liquid intrapulmonary gas carriers during liquid ventilation has been investigated. We established a method of high resolution 3D-19F-MRI of the totally PFC-filled lung. The goal of this study was to investigate longitudinal and circumferential airway strain in the setting of increasing airway pressures on 3D-19F-MR images of the PFC-filled lung. Sixteen female Wistar rats were euthanized and the liquid perfluorocarbon FC-84 instilled into their lungs. 3D-19F-MRI was performed at various intrapulmonary pressures. Measurements of bronchial length and cross-sectional area were obtained from transversal 2D images for each pressure range. Changes in bronchial area were used to determine circumferential strain, while longitudinal strain was calculated from changes in bronchial length. Our method of 3D-19F-MRI allowed clear visualization of the great bronchi. Longitudinal strain increased significantly up to 31.1 cmH2O. The greatest strain could be found in the range of low airway pressures. Circumferential strain increased strongly with the initial pressure rise, but showed no significant changes above 10.4 cmH2O. Longitudinal strain was generally higher in distal airways, while circumferential strain showed no difference. Analysis of mechanical characteristics showed that longitudinal and circumferential airway expansion occurred in an anisotropic fashion. Whereas longitudinal strain still increased with higher pressures, circumferential strain quickly reached a 'strain limit'. Longitudinal strain was higher in distal bronchi, as dense PFCs gravitate to dependent, in this case to dorso-basal parts of the lung, acting as liquid positive end expiratory pressure

  13. Myocardial ischemia in hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Myocardial ischemia in hypertrophic cardiomyopathy is multifactorial and explains the occurrence of angina, in about 50% of patients. The pathophysiology of myocardial ischemia may be explained by the increase of the ventricular mass and relative paucity of the coronary microcirculation; the elevated ventricular filling pressures and myocardial stiffness causing a compression of the coronary microvessels; the impaired coronary vasodilator flow reserve caused by anatomic and functional abnormalities; and the systolic compression of epicardial vessel (myocardial bridges). Myocardial ischemia must be investigated by perfusion scintigraphic methods since its presence influences the prognosis and has relevant clinical implications for management of patients. Patients with hypertrophic cardiomyopathy and documented myocardial ischemia usually need to undergo invasive coronary angiography to exclude the presence of concomitant atherosclerotic coronary disease. (author)

  14. Molecular imaging in myocardial fibrosis

    International Nuclear Information System (INIS)

    With the development of life science and medical technology, myocardial fibrosis is being increasingly recognized as a new therapeutic target for heart diseases. However, traditional methods for detection of myocardial fibrosis, such as myocardial biopsy and laboratory assay of serum metabolites or enzymes, are not satisfactory in meeting the clinical demands because of their intrinsic limitations. Molecular imaging may non-invasively and quantitatively evaluate the presence/absence, degree and turnover of myocardial fibrosis in vivo with good specificity, thus being useful for clinical assessment and intervention. Currently, the commonly used molecular imaging modalities for evaluation of myocardial fibrosis include SPECT, PET and MRI. It is hopeful that the molecular probe for targeted ultrasound technology may also be developed in the near future. This review highlights the current status and future trends of molecular imaging in myocardial fibrosis. (authors)

  15. Acute myocardial infarction.

    Science.gov (United States)

    Rischpler, Christoph

    2016-09-01

    Inflammatory processes after myocardial infarction have gained major interest in recent cardiovascular research. It is believed that not only the degree of cell recruitment to the heart plays a pivotal role in the quality of wound healing after myocardial infarction, but also the balance between different types or even subtypes of cells. It is also this balance which is thought to control key processes in tissue repair, such as apoptosis and neoangiogenesis. In this paper, we aim to review imaging strategies (with a special focus on nuclear molecular imaging strategies) that target cells and processes involved in postischemic inflammation and that have a high potential to be translated into clinic or that are already being used and evaluated in humans. PMID:27225319

  16. Myocardial energy metabolism

    International Nuclear Information System (INIS)

    Myocardial Energy Metabolism offers a scientific survey which may be looked upon as complementary to the classical haemodynamic view of the hart. Sections on Basic mechanisms, Models and techniques, and on Clinical implications make this book a worthwhile acquisition for cardiologists, cardiac surgeons, basic scientists in cardiovascular physiology, as well as for students with a more than average interest in the organ. Not all basic questions with regard to formation, breakdown and usage of energy (ATP) in the hart have been asked or answered, but invited experts from the fields of cardiac biochemistry, (electro)physiology, pharmacology, anaesthesiology and clinical cardiological research have covered the subject extensively from their own points of view. Furthermore, Myocardial Energy Metabolism shows how basic scientific knowledge may be integrated into cardiological practice. The potential that new techniques like NMR and PET-scanning may offer to the cardiologist of the near future becomes particularly clear when the heart is studied with regard to its energy metabolism

  17. Quantitative analysis of exercise 201Tl myocardial emission CT in patients with coronary artery disease

    International Nuclear Information System (INIS)

    The clinical usefulness of quantitative analysis of exercise thallium-201 myocardial emission computed tomography (ECT) was evaluated in coronary artery disease (CAD). The subjects consisted of 20 CAD patients and five normal controls. All CAD patients underwent coronary angiography. Tomographic thallium-201 myocardial imaging was performed with a rotating gamma camera, and long-axial and short-axial myocardial images of the left ventricle were reconstructed. The tomographic images were interpreted quantitatively using circumferential profile analysis. Based on features of regional myocardial thallium-201 kinetics, two types of abnormalities were studied: (1) diminished initial distribution (stress defect) and (2) slow washout of thallium-201, as evidenced by patients' initial thallium-201 uptake and 3-hour washout rate profiles which fell below the normal limits, respectively. Two diagnostic criteria including the stress defect and a combination of the stress defect and slow washout were used to detect coronary artery lesions of significance (>=75 % luminal narrowing). The ischemic volumes were also evaluated by quantitative analysis using thallium-201 ECT. The diagnostic accuracy of the stress defect criterion was 95 % for left anterior descending, 90 % for right, and 70 % for left circumflex coronary artery lesions. The combined criteria of the stress defect and slow washout increased detection sensitivity with a moderate loss of specificity for identifying individual coronary artery lesion. A relatively high diagnostic accuracy was obtained using the stress defect criterion for multiple vessel disease (75 %). Ischemic myocardial volume was significantly larger in triple vessel than in single vessel disease (p < 0.05) using the combined criteria. It was concluded that quantitative analysis of exercise thallium-201 myocardial ECT images proves useful for evaluating coronary artery lesions. (author)

  18. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    OpenAIRE

    N. Maghamipour N. Safaei

    2007-01-01

    Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD) may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical u...

  19. An unusual myocardial infarction

    OpenAIRE

    Di Michele, Sara; MIRABELLI, FRANCESCA; Galzerano, Domenico; Mankad, Sunil

    2014-01-01

    Summary We present a 74-year-old male with a chondrosarcoma, who presented with chest pain. The history, electrocardiogram (ECG), and biomarkers established the diagnosis of myocardial infarction (MI); angiography did not show coronary atherosclerosis and, both initial transthoracic echocardiogram and chest computed tomography (CT), did not demonstrate any cardiac abnormalities. A second echocardiogram following a routine ECG showed presence of a mass involving the right ventricle and the car...

  20. Myocardial protection in sepsis

    OpenAIRE

    Shakar, Simon; Brian D Lowes

    2008-01-01

    Sepsis with myocardial dysfunction is seen commonly. Beta-blockers have been used successfully to treat chronic heart failure based on the premise that chronically elevated adrenergic drive is detrimental to the myocardium. However, recent reports on the acute use of beta-blockers in situations with potential hemodynamic compromise have shown the risks associated with this approach. In critical situations, the main effect of adrenergic activation is to support cardiovascular function. Caution...

  1. Acute myocardial infarction

    OpenAIRE

    De la Vega-Vélez Henrique

    2012-01-01

    The prevalence of the myocardial infarction (MI) was increasing according to the decadesof the 20th century. In the second decade, the electrocardiogram was introduced, animportant diagnostic tool which still has full validity. The professor of the Facultadde Medicina of the Universidad de Cartagena, Colombia, Henrique de la Vega Vélezpublished in 1942 a thematic review that includes three clinical cases of MI. The textallows observing the conceptualization that was managed seventy years ago ...

  2. Acute Myocardial Infarction 19922001

    OpenAIRE

    Robert Schmitz

    2005-01-01

    Heart disease is the leading cause of hospitalization and death in the United States among persons age 65 and older. Acute myocardial infarction (AMI), more commonly known as heart attack, accounted for more than 321,000 hospitalizations among Medicare beneficiaries in 2001. This report presents trends in AMI hospitalization, readmission, and mortality rates from 1992 through 2001 among Medicare fee-for-service beneficiaries across various demographic groups.

  3. Myocardial arterial spin labeling

    OpenAIRE

    Kober, Frank; Jao, Terrence; Troalen, Thomas; Nayak, Krishna S.

    2016-01-01

    Arterial spin labeling (ASL) is a cardiovascular magnetic resonance (CMR) technique for mapping regional myocardial blood flow. It does not require any contrast agents, is compatible with stress testing, and can be performed repeatedly or even continuously. ASL-CMR has been performed with great success in small-animals, but sensitivity to date has been poor in large animals and humans and remains an active area of research. This review paper summarizes the development of ASL-CMR techniques, c...

  4. Effects of inlet circumferential fluctuation on the sweep aerodynamic performance of axial fans/compressors

    Science.gov (United States)

    Gui, Xingmin; Zhu, Fang; Wan, Ke; Jin, Donghai

    2013-10-01

    Swept blades have been widely used in the transonic fan/compressor of aircraft engines with the aids of 3D CFD simulation since the design concept of controlling the shock structure was firstly proposed and successfully tested by Dr. Wennerstrom in the 1980s. However, some disadvantage phenomenon has also been induced by excessively 3D blade geometries on the structure stress insufficiency, vibration and reliability. Much confusion in the procedure of design practice leading us to recognize a new view on the flow mechanism of sweep aerodynamical induction: the new radial equilibrium established by the influence of inlet circumferential fluctuation (CF) changes the inlet flows of blading and induces the performance modification of axial fans/compressors blade. The view is verified by simplified models through numerical simulation and circumferentially averaged analysis in the present paper. The results show that the CF source items which originate from design parameters, such as the spanwise distributions of the loading and blading geometries, contribute to the changing of averaged incidence spanwise distribution, and further more affect the performance of axial fans/compressors with swept blades.

  5. Effects of circumferential rigid wrist orthoses in rehabilitation of patients with radius fracture at typical site

    Directory of Open Access Journals (Sweden)

    Đurović Aleksandar

    2005-01-01

    Full Text Available Background. The use of orthoses is a questionable rehabilitation method for patients with the distal radius fracture at typical site. The aim of this study was to compare the effects of the rehabilitation on patients with radius fracture at the typical site, who wore circumferential static wrist orthoses, with those who did not wear them. Methods. Thirty patients were divided into 3 equal groups, 2 experimental groups, and 1 control group. The patients in the experimental groups were given the rehabilitation program of wearing serially manufactured (off-the-shelf, as well as custom-fit orthoses. Those in the control group did not wear wrist orthoses. Evaluation parameters were pain, edema, the range of the wrist motion, the quality of cylindrical, spherical, and pinch-spherical grasp, the strength of pinch and hand grasp, and patient's assessment of the effects of rehabilitation. Results. No significant difference in the effects of rehabilitation on the patients in experimental groups as opposed to control group was found. Patients in the first experimental group, and in control group were more satisfied with the effects of rehabilitation, as opposed to the patients in the second experimental group (p<0,05. Conclusion. The effects of circumferential static wrist orthoses in the rehabilitation of patients with distal radius fracture at the typical site were not clinically significant. There was no significant difference between the custom and off-the-shelf orthoses.

  6. COMPUTATIONAL AND EXPERIMENTAL STUDY ON TIP LEAKAGE VORTEX OF CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    LI Yang; OUYANG Hua; DU Zhaohui

    2007-01-01

    In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rotors, including the radial rotor, the forward-skewed rotor and the backward-skewed rotor. The three-dimensional viscous flow fields of the fans are computed. In the experiments, the two-dimensional plane particle image velocimetry (PIV) system is used to measure the flow fields in the tip region of three different pitchwise positions of each fan. The results show that the computational results agree well with the experimental data in the flow field of the tip region of each fan. The tip leakage vortex core segments based on method of the eigenmode analysis can display clearly some characteristics of the tip leakage vortex, such as the origination position of tip leakage vortex, the development of vortex strength, and so on. Compared with the radial rotor, the other two skewed rotors can increase the stability of the tip leakage vortex and the increment in the forward-skewed rotor is more than that in the backward-skewed one. Among the tip leakage vortices of the three rotors, the velocity of the vortex in the forward-skewed rotor is the highest in the circumferential direction and the lowest in the axial direction.

  7. Fragmentation of calcified plaque after carotid artery stenting in heavily calcified circumferential stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Masanori; Kodama, Tomonobu; Aikawa, Hiroshi; Onizuka, Masanari; Iko, Minoru; Nii, Kouhei; Hamaguchi, Shuko; Etou, Housei; Sakamoto, Kimiya; Inoue, Ritsurou; Nakau, Hiroya [Fukuoka University Chikushi Hospital, Department of Neurosurgery and Neuroradiology, Fukuoka (Japan); Kazekawa, Kiyoshi [Fukuoka University Chikushi Hospital, Department of Neurosurgery and Neuroradiology, Fukuoka (Japan); Fukuoka University Chikushi Hospital, Department of Neurosurgery, Fukuoka (Japan)

    2010-09-15

    We assessed the morphological change of calcified plaque after carotid artery stenting (CAS) in vessels with heavily calcified circumferential lesions and discuss the possible mechanisms of stent expansion in these lesions. We performed 18 CAS procedures in 16 patients with severe carotid artery stenosis accompanied by plaque calcification involving more than 75% of the vessel circumference. All patients underwent multidetector-row computed tomography (MDCT) to evaluate lesion calcification before and within 3 months after intervention. The angiographic outcome immediately after CAS and follow-up angiographs obtained 6 months post-CAS were examined. The preoperative mean arc of the calcifications was 320.1 {+-} 24.5 (range 278-360 ). In all lesions, CAS procedures were successfully carried out; excellent dilation with residual stenosis {<=}30% was achieved in all lesions. Post-CAS MDCT demonstrated multiple fragmentations of the calcifications in 17 of 18 lesions (94.4%), but only cracks in the calcified plaque without fragmentation in one (5.6%). Angiographic study performed approximately 6 months post-CAS detected severe restenosis in one lesion (5.6%) without fragmentation of calcified plaque. Excellent stent expansion may be achieved and maintained in heavily calcified circumferential carotid lesions by disruption and fragmentation of the calcified plaques. (orig.)

  8. Fragmentation of calcified plaque after carotid artery stenting in heavily calcified circumferential stenosis

    International Nuclear Information System (INIS)

    We assessed the morphological change of calcified plaque after carotid artery stenting (CAS) in vessels with heavily calcified circumferential lesions and discuss the possible mechanisms of stent expansion in these lesions. We performed 18 CAS procedures in 16 patients with severe carotid artery stenosis accompanied by plaque calcification involving more than 75% of the vessel circumference. All patients underwent multidetector-row computed tomography (MDCT) to evaluate lesion calcification before and within 3 months after intervention. The angiographic outcome immediately after CAS and follow-up angiographs obtained 6 months post-CAS were examined. The preoperative mean arc of the calcifications was 320.1 ± 24.5 (range 278-360 ). In all lesions, CAS procedures were successfully carried out; excellent dilation with residual stenosis ≤30% was achieved in all lesions. Post-CAS MDCT demonstrated multiple fragmentations of the calcifications in 17 of 18 lesions (94.4%), but only cracks in the calcified plaque without fragmentation in one (5.6%). Angiographic study performed approximately 6 months post-CAS detected severe restenosis in one lesion (5.6%) without fragmentation of calcified plaque. Excellent stent expansion may be achieved and maintained in heavily calcified circumferential carotid lesions by disruption and fragmentation of the calcified plaques. (orig.)

  9. Transmit-receive eddy current probes for circumferential cracks in heat exchanger tubes

    International Nuclear Information System (INIS)

    Conventional eddy current bobbin probes are known to be ineffectual in detecting circumferential cracks in tubing. Multi-pancake and/or rotating pancake probes are required to detect circumferential cracks. It has recently been demonstrated in CANDU steam generator tubes, with deformation, ferromagnetic deposits, and copper deposits, that multi-channel probes with transmit-receive (T/R) coils are superior to those using surface impedance coils. Unlike rotating probes, the design of a new probe denoted as C3 permits fast, single-scan inspection of a full-length tube at inspection speeds comparable to conventional bobbin probes. Since 1992, the probe has been used routinely for steam generator in-service inspection at 4 CANDU plants. Defective tubes have been plugged and the units returned to service, and they continue to operate without leaks. This paper describes the basic features of T/R surface probes. Two-dimensional voltage diagrams showing computer-derived probe response to frequency, lift-off, carbon steel supports, magnetite deposits and copper deposits are presented and compared with corresponding signals from impedance coils. Theoretical and experimental results show that T/R probes are able to detect defects in the presence of variable lift-off (due to tube-wall deformation) with ten times the signal-to-noise ratio as that exhibited by comparable pancake-type impedance probes. In addition, T/R probes are less sensitive to magnetite deposits, and possess good phase discrimination to internal defects

  10. Status of the steam generator tube circumferential ODSCC degradation experienced at the Doel 4 plant

    Energy Technology Data Exchange (ETDEWEB)

    Roussel, G. [AIB-Vincotte Nuclear, Brussels (Belgium)

    1997-02-01

    Since the 1991 outage, the Doel Unit 4 nuclear power plant is known to be affected by circumferential outside diameter intergranular stress corrosion cracking at the hot leg tube expansion transition. Extensive non destructive examination inspections have shown the number of tubes affected by this problem as well as the size of the cracks to have been increasing for the three cycles up to 1993. As a result of the high percentage of tubes found non acceptable for continued service after the 1993 in-service inspection, about 1,700 mechanical sleeves were installed in the steam generators. During the 1994 outage, all the tubes sleeved during the 1993 outage were considered as potentially cracked to some extent at the upper hydraulic transition and were therefore not acceptable for continued service. They were subsequently repaired by laser welding. Furthermore all the tubes not sleeved during the 1993 outage were considered as not acceptable for continued service and were repaired by installing laser welded sleeves. During the 1995 outage, some unexpected degradation phenomena were evidenced in the sleeved tubes. This paper summarizes the status of the circumferential ODSCC experienced in the SG tubes of the Doel 4 plant as well as the other connected degradation phenomena.

  11. Elastic-plastic finite element analyses for reducers with constant-depth internal circumferential surface cracks

    International Nuclear Information System (INIS)

    In this study, a 3-D automatic elastic-plastic finite element mesh generator is established to accurately predict the J-integral value of an arbitrary reducer with a constant-depth internal circumferential surface crack under bending and axial force. The contact pairs are used on the crack surfaces to simulate the actual contact behaviors of the crack model under loadings. In order to verify the accuracy of the proposed elastic-plastic finite element model for a reducer with a surface crack, the cracked straight pipe models are generated according to a special modeling procedure for a flawed reducer. The J-integral values along the crack front of surface crack are calculated and compared with the straight pipe models which have been verified in the previous published studies. Based on the comparison of computed results, good agreements are obtained to show the accuracy of present numerical models. More confidence on using the 3-D elastic-plastic finite element analysis for reducers with internal circumferential surface cracks can be thus established in this work

  12. Recent evaluations of crack-opening-area in circumferentially cracked pipes

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, S.; Brust, F.; Ghadiali, N.; Wilkowski, G.; Miura, N.

    1997-04-01

    Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. The leak rates depend on the crack-opening area of the through-wall crack in the pipe. In addition to LBB analyses which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section XI. The objectives of this study were to review, evaluate, and refine current predictive models for performing crack-opening-area analyses of circumferentially cracked pipes. The results from twenty-five full-scale pipe fracture experiments, conducted in the Degraded Piping Program, the International Piping Integrity Research Group Program, and the Short Cracks in Piping and Piping Welds Program, were used to verify the analytical models. Standard statistical analyses were performed to assess used to verify the analytical models. Standard statistical analyses were performed to assess quantitatively the accuracy of the predictive models. The evaluation also involved finite element analyses for determining the crack-opening profile often needed to perform leak-rate calculations.

  13. Fracture behavior of circumferentially surface-cracked elbows. Technical report, October 1993--March 1996

    International Nuclear Information System (INIS)

    This report presents the results from Task 2 of the Second International Piping Integrity Research Group (IPIRG-2) program. The focus of the Task 2 work was directed towards furthering the understanding of the fracture behavior of long-radius elbows. This was accomplished through a combined analytical and experimental program. J-estimation schemes were developed for both axial and circumferential surface cracks in elbows. Large-scale, quasi-static and dynamic, pipe-system, elbow fracture experiments under combined pressure and bending loads were performed on elbows containing an internal surface crack at the extrados. In conjunction with the elbow experiments, material property data were developed for the A106-90 carbon steel and WP304L stainless steel elbow materials investigated. A comparison of the experimental data with the maximum stress predictions using existing straight pipe fracture prediction analysis methods, and elbow fracture prediction methods developed in this program was performed. This analysis was directed at addressing the concerns regarding the validity of using analysis predictions developed for straight pipe to predict the fracture stresses of cracked elbows. Finally, a simplified fitting flaw acceptance criteria incorporating ASME B2 stress indices and straight pipe, circumferential-crack analysis was developed

  14. Nonlinear Local Bending Response and Bulging Factors for Longitudinal and Circumferential Cracks in Pressurized Cylindrical Shells

    Science.gov (United States)

    Young, Richard D.; Rose, Cheryl A.; Starnes, James H., Jr.

    2000-01-01

    Results of a geometrically nonlinear finite element parametric study to determine curvature correction factors or bulging factors that account for increased stresses due to curvature for longitudinal and circumferential cracks in unstiffened pressurized cylindrical shells are presented. Geometric parameters varied in the study include the shell radius, the shell wall thickness, and the crack length. The major results are presented in the form of contour plots of the bulging factor as a function of two nondimensional parameters: the shell curvature parameter, lambda, which is a function of the shell geometry, Poisson's ratio, and the crack length; and a loading parameter, eta, which is a function of the shell geometry, material properties, and the applied internal pressure. These plots identify the ranges of the shell curvature and loading parameters for which the effects of geometric nonlinearity are significant. Simple empirical expressions for the bulging factor are then derived from the numerical results and shown to predict accurately the nonlinear response of shells with longitudinal and circumferential cracks. The numerical results are also compared with analytical solutions based on linear shallow shell theory for thin shells, and with some other semi-empirical solutions from the literature, and limitations on the use of these other expressions are suggested.

  15. Fracture behavior of circumferentially surface-cracked elbows. Technical report, October 1993--March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Kilinski, T.; Mohan, R.; Rudland, D.; Fleming, M. [and others

    1996-12-01

    This report presents the results from Task 2 of the Second International Piping Integrity Research Group (IPIRG-2) program. The focus of the Task 2 work was directed towards furthering the understanding of the fracture behavior of long-radius elbows. This was accomplished through a combined analytical and experimental program. J-estimation schemes were developed for both axial and circumferential surface cracks in elbows. Large-scale, quasi-static and dynamic, pipe-system, elbow fracture experiments under combined pressure and bending loads were performed on elbows containing an internal surface crack at the extrados. In conjunction with the elbow experiments, material property data were developed for the A106-90 carbon steel and WP304L stainless steel elbow materials investigated. A comparison of the experimental data with the maximum stress predictions using existing straight pipe fracture prediction analysis methods, and elbow fracture prediction methods developed in this program was performed. This analysis was directed at addressing the concerns regarding the validity of using analysis predictions developed for straight pipe to predict the fracture stresses of cracked elbows. Finally, a simplified fitting flaw acceptance criteria incorporating ASME B2 stress indices and straight pipe, circumferential-crack analysis was developed.

  16. Uncertainty analysis for the net-section-collapse failure criterion of circumferentially cracked cylinders for multiple arbitrary-shaped circumferential cracks

    International Nuclear Information System (INIS)

    In this manuscript, a generalized net-section-collapse (NSC) failure criterion of circumferentially cracked pipes with multiple arbitrary-shaped cracks is presented. This generalized NSC formulation is capable of predicting the NSC moment of a pipe with multiple arbitrary-shaped cracks distributed around the circumference of the pipe, regardless of whether they are distributed symmetrically or not. The case in which internal cracks straddle the compressive zone is accounted for in the present formulation. Closed form solutions are provided for the maximum moments of pipes containing multiple cracks with idealized shapes, namely constant depth, semi-elliptical and parabolic crack profiles. Through a series of examples, the results show the effectiveness and accuracy of the method. Using this method, quantification of the effect of the crack profile uncertainty on the maximum bending moment sustained by a cracked pipe is evaluated. It is demonstrated that while the uncertainty associated with the surface roughness of the crack profile has little to no effect on the maximum bending moment, irregular shape profiles have, not surprisingly, a large effect on the estimation of the maximum bending moment. In fact, it is mathematically shown that the uncertainty associated with the maximum bending moment is proportional to the magnitude of the crack profile uncertainty and inversely proportional to the square root of the uncertainty sampling size (i.e. surface roughness vs. irregular crack profile)

  17. New software for raw data mask processing increases diagnostic ability of myocardial SPECT imaging

    International Nuclear Information System (INIS)

    Increased activity of myocardial perfusion tracer technetium-99m in liver and hepatobiliary system causes streak artifacts, which may affect clinical diagnosis. We developed a mask-processing tool for raw data generated using technetium-99m as a myocardial perfusion tracer. Here, we describe improvements in image quality under the influence of artifacts caused by high accumulation in other organs. A heart phantom (RH-2) containing 15 MBq of pertechnetate was defined as model A. Model B was designed in the same phantom containing ten times of cardiac radioactivity overlapping with other organs. Variance in the vertical profile count in the lower part of the myocardial inferior wall and in the myocardial circumferential profile curve were investigated in a phantom and clinical cases using our raw data masking (RDM) software. The profile variances at lower parts of myocardial inferior walls were 965.43 in model A, 1390.11 in model B and 815.85 in B-RDM. The mean ±SD of myocardial circumferential profile curves were 83.91±7.39 in model A, 69.61±11.45 in model B and 82.68±9.71 in model B-RDM. For 11 clinical images with streak artifacts, the average of the variance significantly differed between with and without RDM (3.95 vs. 21.05; P<0.05). For 50 clinical images with hepatic accumulation artifacts, the average of the variance on vertical profiles on images with and without RDM significantly differed (5.99 vs. 15.59; P<0.01). Furthermore, when a segment with <60% uptake in polar maps was defined as abnormal, the average extent score of 1 h (Tc-1h), 5 min of RDM (Tc-0h-RDM) and 5 min of non-RDM (Tc-0h-non-RDM) were 2.25±3.12, 2.35±3.16, and 1.37±2.41, respectively. Differences were significant between Tc-1h and Tc-0h-non-RDM (P<0.005) but not between Tc-1h and Tc-0h-RDM. Batch processing was enabled in all frames by shifting the myocardium to the center of rotation using this software. The waiting time between infusion and image acquisition should be decreased

  18. Noninvasive assessment of changes in myocardial perfusion and ventricular performance following exercise training

    International Nuclear Information System (INIS)

    Seventeen coronary patients (CAD) underwent 201Tl treadmill and radionuclide (RNV) ejection fraction supine bicycle testing before and after 5.6 +/- 1.6 (mean +/- SD) months of an exercise program. Thallium data were assessed both using analog images and a computerized circumferential profile technique. Patients exercised on the treadmill to a higher workload after the exercise program, but achieved a similar pressure-rate product. When interpreting the analog thallium images, only 50% agreement was obtained for the assessment of changes in myocardial perfusion (pre/post-training). The computer technique, however, had low inter-intraobserver variability (6%) and better agreement (90.5%). Using the circumferential profile method, five patients improved (a total of 11 regions) and one patient worsened (with two regions). Before the exercise program, the ejection fraction (EF) response to supine bike exercise was normal (an increase greater than 11%) in four, flat in seven, and severely abnormal (a decrease of more than 4%) in six patients. After the exercise program, even though achieving similar or higher pressure-rate products, six patients improved their EF response, nine did not change, and two worsened. Of the five patients who improved their thallium images, one improved his EF response, two remained normal, and two did not change. One patient worsened both his thallium study and the EF response after the exercise program. Changes in thallium exercise images and the EF response to supine exercise occurred in our patients after an exercise program, but were not always concordant. Indeed, of five patients with exercise-induced ischemic ST changes before and after training, the EF response improved in three whereas myocardial perfusion was unchanged. Reasons for this lack of agreement are discussed, and have been considered in the planning of a randomized trial of the effects of an exercise program on myocardial perfusion and function

  19. The Mechanism of Stall Margin Improvement in a Centrifugal Compressor with the Air Bleeding Circumferential Grooves Casing Treatment

    Science.gov (United States)

    Gao, P.; Chu, W. L.; Wu, Y. H.

    The air bleeding circumferential grooves casing treatment has the potential to extent the operating range of centrifugal compressor with no loss in efficiency. A time accurate 3-dimentional numerical simulation was performed in a low speed centrifugal compressor with the air bleeding circumferential grooves casing treatment. The numerical results agreed well with experimental test data for the global performance. Detailed analyses of the flow visualization at the tip of blades have exposed the different tip flow topologies between the cases with casing treatment and with untreated smooth wall, and the reasons how the second flow vortex is retrained. The mechanism of stall margin improvement is gained finally.

  20. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    Directory of Open Access Journals (Sweden)

    N. Maghamipour N. Safaei

    2007-06-01

    Full Text Available Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical unroofing of myocardial bridging. Patients had a myocardial bridge of at least 3 cm in length in the middle of LAD and with more than 70% compression during systole. Unroofing was performed with cardiopulmonary bypass in 16 and with off pump technique in 10 patients. In 6 patients repeat angiographies for control of myotomy were done. In one of them a nonsignificant 20% narrowing was seen. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation in 24 patients. Two patients had residual narrowing. With off pump technique, 1 patient had perforation of the right ventricle and 1 patient underwent reoperation because of incomplete unroofing during the first operation. None of the patients with cardiopulmonary bypass technique had residual chest pain or other complications. Surgical unroofing of myocardial bridging with the aid of cardiopulmonary bypass is a safe and easy procedure with low operative risk and with excellent functional results.

  1. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

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

    1996-01-01

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

  2. Assessment of myocardial viability.

    Science.gov (United States)

    Travin, Mark I; Bergmann, Steven R

    2005-01-01

    The prevalence of left ventricular (LV) dysfunction and resultant congestive heart failure is increasing. Patients with this condition are at high risk for cardiac death and usually have significant limitations in their lifestyles. Although there have been advances in medical therapy resulting in improved survival and well being, the best and most definitive therapy, when appropriate, is revascularization. In the setting of coronary artery disease, accounting for approximately two thirds of cases of congestive heart failure, LV dysfunction often is not the result of irreversible scar but rather caused by impairment in function and energy use of still viable-myocytes, with the opportunity for improved function if coronary blood flow is restored. Patients with LV dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischemia but at the same time benefit most from revascularization. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy, whether using thallium-201, Tc-99m sestamibi, or Tc-99m tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management. Metabolic imaging with positron emission tomography radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularization, including some patients referred instead for cardiac transplantation. Other noninvasive modalities, such as stress echocardiography, also facilitate the assessment of myocardial viability, but there are advantages and disadvantages compared with the nuclear techniques. Nuclear imaging appears to require fewer viable cells for detection, resulting in a higher sensitivity but a lower specificity than stress

  3. Spiral MR myocardial tagging.

    Science.gov (United States)

    Ryf, Salome; Kissinger, Kraig V; Spiegel, Marcus A; Börnert, Peter; Manning, Warren J; Boesiger, Peter; Stuber, Matthias

    2004-02-01

    In the present study, complementary spatial modulation of magnetization (CSPAMM) myocardial tagging was extended with an interleaved spiral imaging sequence. The use of a spiral sequence enables the acquisition of grid-tagged images with a tagline distance as low as 4 mm in a single breath-hold. Alternatively, a high temporal resolution of 77 frames per second was obtained with 8-mm grid spacing. Ten healthy adult subjects were studied. With this new approach, high-quality images can be obtained and the tags persist throughout the entire cardiac cycle. PMID:14755646

  4. Failure behaviour of a piping system with a circumferentially orientated flaw

    International Nuclear Information System (INIS)

    The experiments were conducted on the recently installed feedwater line of the HDR reactor in Kahl. The investigations were focused on analysing both the crack propagation of a circumferentially flowed pipe under the influence of corrosion and cyclic load, together with the pipeline's subsequent failure behaviour. The experimental conditions were selected in a manner representing those which can, for example, prevait during start-up or shut-down of reactor. To this aim, the pipes were internally stressed with high pressure and temperature oxygenic water in conjunction with an externally applied bending moment. The investigations are supplemented by elastic-plastic triaxial finite element (FE) calculations for various assumed crack configurations, both prior to and following the experiments, thus granting a fracture-mechanical assessment of the structural behaviour. (orig./DG)

  5. Lower bound limit load of a circumferentially cracked pipe under combined mechanical loading

    International Nuclear Information System (INIS)

    In a study on extension of the reference stress method, for J simplified assessment, to a three dimensional (3D) configuration under combined loading, lower bound limit analysis has been developed by J. Desquines. In the present paper the limit load for cracked pipe, with a 3D circumferential flaw, under pressure, tension and bending is detailed. The limit load is explicitly defined as a yield surface is the 3D space loading. A simple algorithm is proposed to solve the non linear problem associated to the reference stress calculation. Moreover, the lower bound solution is compared with elastic compensation method (ECM) results computed on a 3D finite element mesh of the cracked pipe. The lower bound yield surface underestimates the numerical limit loads with a discrepancy lower than 20%. (orig.)

  6. Crack shape developments and leak rates for circumferential complex-cracked pipes

    Energy Technology Data Exchange (ETDEWEB)

    Brickstad, B.; Bergman, M. [SAQ Inspection Ltd., Stockholm (Sweden)

    1997-04-01

    A computerized procedure has been developed that predicts the growth of an initial circumferential surface crack through a pipe and further on to failure. The crack growth mechanism can either be fatigue or stress corrosion. Consideration is taken to complex crack shapes and for the through-wall cracks, crack opening areas and leak rates are also calculated. The procedure is based on a large number of three-dimensional finite element calculations of cracked pipes. The results from these calculations are stored in a database from which the PC-program, denoted LBBPIPE, reads all necessary information. In this paper, a sensitivity analysis is presented for cracked pipes subjected to both stress corrosion and vibration fatigue.

  7. Analysis of parameters likely to explain the secondary side circumferential cracking of steam generator

    International Nuclear Information System (INIS)

    In 1990, a new type of damage mechanism was brought to light by means of eddy current inspections in Steam Generator (SG) tube bundle. This is circumferential cracking, started on the outer wall of the tubes. These cracks generally appear below the level of the tube sheet. By the end of 1993, 89 tubes with this king of damage were discovered in the French nuclear power plants: 85 of these were located on the 6 SG's of 2 units of Dampierre. We present here the work carried out to provide better understanding of this phenomenon. It involves statistical analysis of data from experience feedback, together with analysis of the thermohydraulic conditions found on the tube sheet. (authors). 8 figs., 2 refs

  8. Development of circumferential seal for helicopter transmissions: Results of bench and flight tests

    Science.gov (United States)

    Strom, T. N.; Ludwig, L. P.

    1975-01-01

    A modified circumferential segmented ring seal was designed for direct replacement of a helicopter transmission elastomeric lip seal operating on a shaft diameter of 13.91 centimeters (5.481 in.) at sliding velocities to 52.48 m/sec (10 330 ft/min). The modifications involved the garter spring tension, shaft roundness, seal housing flatness, and pumping grooves to inhibit leakage. Operation of the seals in bench tests under simulated helicopter transmission conditions revealed that the seal leakage rate was within acceptable limits and that the wear rate was negligible. The low leakage and wear rates were confirmed in flight tests of 600 and 175 hours (sliding speed, 48.11 m/sec (9470 ft/min)). An additional 200 hours of air worthiness qualification testing (aircraft tie down) demonstrated that the seal can operate at the advanced sliding conditions of 52.48 m/sec (10 330 ft/min).

  9. Quantitative lymphoscintigraphy in post-mastectomy lymphedema: correlation with circumferential measurements

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon Young; Lee, Kyung Han; Kim, Sang Eun; Kim, Byung Tae; Hwang, Jee Hea; Lee, Byung Boong [Samsung Medical Center, Seoul (Korea, Republic of)

    1997-07-01

    An objective measure for the severity and progression is important for the management of lymphedema. To evaluate the usefulness of lympho-scintigraphy in this regard, we compared various quantitative indices from upper extremity lymphoscintigraphy with circumferential measurements, before and after physiotheraphy. Upper extremity lymphoscintigraphy was performed in 38 patients with unilateral postmastectomy lymphedema. Tc-99m antimony sulfide colloid (37 MBq) was injected s.c. into the second and third interdigital spaces. The injection sites were imaged immediately after injection. After standardized exercise for 15 min, upper extremity images were acquired 30 min, 1 hr and 2 hr after injection. The clearance of the injection site (CL), and % uptake in regional lymph nodes (%LN) and soft tissue of the extremity (i.e., the degree of dermal backflow) (%EXT) compared to the initial injection site were calculated. Circumference of each extremity was measured at 7 levels; the severity of lymphedema was expressed as the percentage difference of total circumferential difference (TCD) between healthy and edematous extremities compared to the total circumference of healthy extremity (%TCD). In 19 patients who received physiotherapy, the therapeutic effect was measured by % decrease of TCD (%DTCD) before and after therapy (Raines. et al., 1977). The quantitative indices calculated in the image at 2 hr p.i. had better correlation with either %TCD or %DTCD than those from earlier images (Table). The CL, %LN and %EXT of edematous extremity had a significant correlation with TCD. The %EXT was correlated best with either TCD or %DTCD. The results suggest that the %EXT which corresponds to the degree of dermal backflow may be a simple and useful quantitative index for evaluating the severity and progression in lymphedema and predicting the effect of therapy.

  10. Quantitative lymphoscintigraphy in post-mastectomy lymphedema: correlation with circumferential measurements

    International Nuclear Information System (INIS)

    An objective measure for the severity and progression is important for the management of lymphedema. To evaluate the usefulness of lympho-scintigraphy in this regard, we compared various quantitative indices from upper extremity lymphoscintigraphy with circumferential measurements, before and after physiotheraphy. Upper extremity lymphoscintigraphy was performed in 38 patients with unilateral postmastectomy lymphedema. Tc-99m antimony sulfide colloid (37 MBq) was injected s.c. into the second and third interdigital spaces. The injection sites were imaged immediately after injection. After standardized exercise for 15 min, upper extremity images were acquired 30 min, 1 hr and 2 hr after injection. The clearance of the injection site (CL), and % uptake in regional lymph nodes (%LN) and soft tissue of the extremity (i.e., the degree of dermal backflow) (%EXT) compared to the initial injection site were calculated. Circumference of each extremity was measured at 7 levels; the severity of lymphedema was expressed as the percentage difference of total circumferential difference (TCD) between healthy and edematous extremities compared to the total circumference of healthy extremity (%TCD). In 19 patients who received physiotherapy, the therapeutic effect was measured by % decrease of TCD (%DTCD) before and after therapy (Raines. et al., 1977). The quantitative indices calculated in the image at 2 hr p.i. had better correlation with either %TCD or %DTCD than those from earlier images (Table). The CL, %LN and %EXT of edematous extremity had a significant correlation with TCD. The %EXT was correlated best with either TCD or %DTCD. The results suggest that the %EXT which corresponds to the degree of dermal backflow may be a simple and useful quantitative index for evaluating the severity and progression in lymphedema and predicting the effect of therapy

  11. MYOCARDIAL INFARCTION TYPE 2. MYTH OR REALITY?

    OpenAIRE

    V. V. Zhelnov; N. V. Dyatlov; L. I. Dvoretsky

    2016-01-01

    According to The Third Definition of Myocardial Infarction there are five types of myocardial infarction depending on pathogenesis. This review provides actual data about myocardial infarction type 2 mechanism including diagnosis management, epidemiological characteristic and patient prognosis. Previously published data shows discordant information about myocardial infarction type 2 frequency, treatment and diagnostic options. Our clinical observation illustrates these severities in diagnosis...

  12. Regional left ventricular myocardial contraction abnormalities and asynchrony in patients with hypertrophic cardiomyopathy evaluated by magnetic resonance spatial modulation of magnetization myocardial tagging

    International Nuclear Information System (INIS)

    Global left ventricular (LV) pump function is generally preserved in patients with hypertrophic cardiomyopathy (HCM). However, it is unknown whether regional myocardial contractility is impaired, especially in nonhypertrophied regions. The purpose of this study was to evaluate regional LV myocardial contraction in patients with HCM using magnetic resonance (MR) spatial modulation of magnetization (SPAMM) myocardial tagging. The study group comprised 20 patients with asymmetric septal hypertrophy (HCM group) and 16 age-matched normal patients (control group), and data were collected using transthoracic M-mode and 2-dimensional echocardiography, and MR SPAMM myocardial tagging. The systolic strain ratio, maximum systolic strain velocity, and time from end-diastole to maximum systolic strain (ΔT) in the anterior, ventricular septal, inferior and lateral regions for 2 LV short-axis sections at the levels of the chordae tendineae and papillary muscles were measured at 50-ms intervals by MR myocardial tagging. The end-diastolic anterior and ventricular septal wall thicknesses and LV mass index were significantly different between the HCM and control groups. The systolic strain ratio for all 4 walls, particularly the anterior and ventricular septal regions, was significantly lower in the HCM group. In the HCM group, the maximum systolic strain velocity was significantly lower and ΔT was significantly shorter for all 4 walls, particularly the anterior and ventricular septal regions. The standard deviation for the ΔT, calculated from the ΔT for the 8 regions of the 2 LV short-axis sections, was significantly greater in the HCM group. In conclusion, regional LV myocardial contraction is impaired in both hypertrophied and nonhypertrophied regions, and systolic LV wall asynchrony occurs in patients with HCM. (author)

  13. Valsartan after myocardial infarction.

    Science.gov (United States)

    Güleç, Sadi

    2014-12-01

    One of the important problems of the patients undergoing acute myocardial infarction (MI) is early development of heart failure. It has been revealed in various studies that renin-angiotensin-aldosterone system (RAAS) has a significant role in this process. The studies conducted with angiotensin converting enzyme (ACE) inhibitors have resulted in decreased mortality rate. Another RAAS blocker which was discovered about ten years later than other ACE inhibitors in historical process is angiotensin receptor blockers (ARB) inhibiting the efficiency of angiotensin 2 by binding to angiotensin 1 receptor. Valsartan is one of the molecules of this group, which has higher number of large-scale randomized clinical studies. In this review, following presentation of a general overview on heart failure after acute MI, the efficiency of ARBs in this patient group will be discussed. This discussion will mostly emphasize the construction, outcomes and clinical importance of VALIANT (VALsartan In Acute myocardial iNfarcTion), which is the study on valsartan after acute MI heart failure. PMID:25604205

  14. Initial experience with circumferential pulmonary vein ablation guided by fusion of magnetic resonance imaging with three-dimensional electroanatomic mapping

    Institute of Scientific and Technical Information of China (English)

    TANG Kai; MA Jian; MA Fu-sheng; JlA Yu-he; ZHANG Shu

    2006-01-01

    @@ Catheter ablation for the treatment of atrial fibrillation (AF) has been a focal target of electrophysiological study in recent years. Up to date,circumferential pulmonary vein ablation (CPVA)guided by three-dimensional (3-D) electroanatomic mapping (Carto, USA) has been one of the most favourable procedures for the treatment of AF.

  15. The Influence of Hospital Volume on Circumferential Resection Margin Involvement: Results of the Dutch Surgical Colorectal Audit.

    Science.gov (United States)

    Gietelink, Lieke; Henneman, Daniel; van Leersum, Nicoline J; de Noo, Mirre; Manusama, Eric; Tanis, Pieter J; Tollenaar, Rob A E M; Wouters, Michel W J M

    2016-04-01

    This population-based study evaluates the association between hospital volume and CRM (circumferential resection margin) involvement, adjusted for other confounders, in rectal cancer surgery. A low hospital volume (CRM involvement (odds ratio = 1.54; 95% CI: 1.12-2.11). PMID:25790120

  16. Burn-out, Circumferential Film Flow Distribution and Pressure Drop for an Eccentric Annulus with Heated Rod

    DEFF Research Database (Denmark)

    Andersen, P. S.; Jensen, A.; Mannov, G.;

    1974-01-01

    Measurements of (1) burn-out, (2) circumferential film flow distribution, and (3) pressure drop in a 17 × 27.2 × 3500 mm concentric and eccentric annulus geometry are presented. The eccentric displacement was varied between 0 and 3 mm. The working fluid was water. Burn-out curves at 70 bar...... flow variation on burn-out is discussed....

  17. High speed OH-PLIF measurement of self-excited circumferential instabilities in an annular combustion chamber

    Science.gov (United States)

    Worth, Nicholas; Dawson, James

    2012-11-01

    Self-excited thermo-acoustic instabilities are a significant issue in the development of lean burn gas turbine combustors. Such instabilities arise through coupling of the unsteady heat release and acoustic waves, which can propagate both longitudinally and circumferentially in annular combustor geometries. Although a large number of studies have investigated longitudinal fluctuations in single axisymmetric flames, it is currently uncertain whether these results can be used to emulate circumferential oscillations in annular geometry. Therefore, the aim of the current project is to investigate the flame dynamics in an annular model gas turbine combustor during self-excited circumferential oscillations. Pressure measurements are used to characterise the circumferential oscillations, with high-speed OH chemiluminescence and OH-PLIF used to capture the flame dynamics. The flame structure and dynamics are significantly affected by both the proximity of neighbouring flames and the excitation mode; with different responses observed for small and large separation distances, and standing and spinning modes. These observations indicate that results from single flame investigations may only be representative of self-excited flames in annular geometry under in a limited set of conditions.

  18. Circumferential fusion is dominant over posterolateral fusion in a long-term perspective: cost-utility evaluation of a randomized controlled trial in severe, chronic low back pain

    DEFF Research Database (Denmark)

    Soegaard, Rikke; Bünger, Cody E; Christiansen, Terkel;

    2007-01-01

    BACKGROUND DATA: The cost-effectiveness of circumferential fusion in a long-term perspective is uncertain but nonetheless highly relevant as the ISSLS prize winner 2006 in clinical studies reported the effect of circumferential fusion superior to the effect of posterolateral fusion. A recent trial found no...

  19. Finite Element Limit Pressures for Circumferential Through-Wall Cracks in the Interface between Elbow and Pipe

    International Nuclear Information System (INIS)

    Among integrity assessment method based on a fracture mechanics concept for piping system, a limit load method is one of the important way to predict a maximum load carrying capacity in the materials with high ductility in the sense that it is used to either assess directly structural integrity of pipe based on fully plastic fracture mechanics or calculate elasticplastic fracture mechanics parameters based on reference stress concept. In nuclear power plants, piping system often involves elbows welded to straight pipe. Since welded regions are vulnerable to cracking, it is important to predict an accurate limit load for pipes with a crack in the interface between elbows and attached pipes. However, although extensive works have been made for developing limit analysis methods for cracked pipes, they were mainly for straight pipes. Recently, limit moment solutions for elbow that is attached to straight pipe with a circumferential through-wall crack(TWC) in the interface were proposed, whereas limit pressure for this geometry is not suggested yet. In this context, plastic limit pressures of circumferential TWCs between elbow and straight pipe were calculated in the present study considering geometric parameters such as an elbow curvature, a pipe size and a crack length. In the present study, the FE plastic limit analyses for circumferential TWC in the interface between elbow and pipe under internal pressure were conducted based on elastic perfectly plastic assumption. Based on the present FE results, it is found that plastic limit pressures of straight pipes with circumferential TWC are not appropriate for predicting plastic limit pressures of circumferential TWC in the interface between elbow and pipe for shorter crack length

  20. Finite Element Limit Pressures for Circumferential Through-Wall Cracks in the Interface between Elbow and Pipe

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yoon-Young; Han, Tae-Song; Huh, Nam-Su [Seoul National Univ., Seoul (Korea, Republic of); Jeong, Jae-Uk [Sungkyunkwan Univ., Suwon (Korea, Republic of)

    2014-10-15

    Among integrity assessment method based on a fracture mechanics concept for piping system, a limit load method is one of the important way to predict a maximum load carrying capacity in the materials with high ductility in the sense that it is used to either assess directly structural integrity of pipe based on fully plastic fracture mechanics or calculate elasticplastic fracture mechanics parameters based on reference stress concept. In nuclear power plants, piping system often involves elbows welded to straight pipe. Since welded regions are vulnerable to cracking, it is important to predict an accurate limit load for pipes with a crack in the interface between elbows and attached pipes. However, although extensive works have been made for developing limit analysis methods for cracked pipes, they were mainly for straight pipes. Recently, limit moment solutions for elbow that is attached to straight pipe with a circumferential through-wall crack(TWC) in the interface were proposed, whereas limit pressure for this geometry is not suggested yet. In this context, plastic limit pressures of circumferential TWCs between elbow and straight pipe were calculated in the present study considering geometric parameters such as an elbow curvature, a pipe size and a crack length. In the present study, the FE plastic limit analyses for circumferential TWC in the interface between elbow and pipe under internal pressure were conducted based on elastic perfectly plastic assumption. Based on the present FE results, it is found that plastic limit pressures of straight pipes with circumferential TWC are not appropriate for predicting plastic limit pressures of circumferential TWC in the interface between elbow and pipe for shorter crack length.

  1. Evaluation of myocardial involvement in muscular dystrophy with thallium-201 emission computed tomography

    International Nuclear Information System (INIS)

    The clinical usefulness of thallium-201 myocardial perfusion scanning with emission computed tomography (ECT) for evaluation of left ventricular myocardial fibrosis was assessed on 47 patients with Duchenne (DMD), facioscapulohumeral (FSH), limb-girdle (LG) and myotonic (MT) dystrophy. Trans-, long- and short-axial images were interpreted quantitatively by circumferential profile analysis, and the fibrotic tissue size (%FIB) was estimated by integration of hypoperfused areas in 6 to 8 consecutive short-axial slices. Lung/mediastinum count ratios (L/M ratio), LV cavity dilatation, aneurysm formation and cardiac malrotations were also assessed with ECT. Distinct ECT perfusion defect was observed in 26 of 29 DMDs, and in 11 of 18 patients with other types. Perfusion defect was demonstrated in 95 of total 235 segments, and was observed specifically in the posterior wall (82 %) and the apex (65 %) in DMD, and was scattered in all LV wall segments in FSH, LG, and MT. Percent FIB correlated significantly with L/M ratio (r = 0.82, p < 0.01), and did not with age or clinical stage score. ECT showed marked LV dilatation in 7, apical aneurysm in 5 and cardiac malrotation in 23 of the 47 patients. In conclusion, ECT was considered to be a useful clinical means of evaluating myocardial involvement in patients with muscular dystrophy. (author)

  2. Evaluation of myocardial involvement in muscular dystrophy with Thallium-201 emission computed tomography

    International Nuclear Information System (INIS)

    The clinical usefulness of quantitative analysis of thallium-201 emission computed tomography (ECT) for evaluation of left ventricular myocardial fibrosis was assessed on 45 patients with Duchenne(D), facioscapulohumeral(FSH), limbgirdle(LG) and myotonic(M) dystrophy. Trans-,long- and short-axial images were interpreted quantitatively using circumferential profile analysis, and the fibrotic tissue size (%FIB) was estimated by integration of hypoperfused areas in 6 to 8 consecutive short-axial slices. Lung/mediastinum count ratios (L/M ratio) were also assessed. Distinct ECT defects were found in 42 patients (all cases of D, FSH and LG, and 2 of 5 MTs). ECT defects were observed specifically in the posterolateral wall (71%) and apex (58%) in D, and were scattered in all LV walls in FSHG, LG and MT. ECG and VCG underestimated the extent of myocardial fibrosis in 17 patients (40%). Percent FIBs coincided with fibrotic tissue sizes proven by autopsy. Body-surface ECG should be influenced by cardiac position and rotation in the thorax, which were often observed in these disease entities. These factors were also assessed with ECT. The authors conclude; ECT to be useful for non-invasive evaluation of myocardial fibrosis in patients with various types of muscular dystrophy

  3. Oxytocin ameliorates the immediate myocardial injury in heart transplant through down regulation of the neutrophil dependent myocardial apoptosis

    Directory of Open Access Journals (Sweden)

    F Fadhil Al-Amran

    2014-01-01

    Conclusion: Oxytocin ameliorates myocardial injury in heart transplant through down-regulation the myocardial inflammatory response, reactive oxygen species, and neutrophil-dependant myocardial apoptosis.

  4. Myocardial bridging as a cause of acute myocardial infarction: a case report

    OpenAIRE

    Emiroglu Yunus; Gunduz Huseyin; Akdemir Ramazan; Uyan Cihangir

    2002-01-01

    Abstract Background Systolic compression of a coronary artery by overlying myocardial tissue is termed myocardial bridging. Myocardial bridging usually has a benign prognosis, but some cases resulting in myocardial ischemia, infarction and sudden cardiac death have been reported. We are reporting a case of myocardial bridging which was complicated with acute myocardial infarction associated with inappropriate blood donation. Case presentation A 33 year-old-man was admitted to our emergency wi...

  5. Depression following myocardial infarction

    DEFF Research Database (Denmark)

    Larsen, Karen Kjær

    2013-01-01

    Myocardial infarction (MI) is a severe life event that is accompanied by an increased risk of depression. Mounting evidence suggests that post-MI depression is associated with adverse outcomes, but the underlying mechanisms of this association remain unclear, and no previous studies have examined...... whether the mental burden of MI is so heavy that it increases the risk of suicide. Although post-MI depression is common and burdensome, the condition remains under-recognised and under-treated. The development of new strategies to improve the quality of care for people with post-MI depression requires...... thorough understanding of the mechanisms that influence the prognosis as well as knowledge of the present care provided. The purpose of this PhD thesis is accordingly subdivided into four specific aims: 1. To estimate the prevalence of depression in people with MI after three months, and to estimate the...

  6. ST elevation without myocardial infarction.

    Science.gov (United States)

    Bitar, Zouheir Ibrahim; Swede, Mohammad; Almerri, Khaled

    2014-01-01

    Acute myocarditis may mimic myocardial infarction because the affected patients report 'classical' chest pain; the ECG changes and echocardiography are identical to those observed in acute coronary syndromes, and serum markers are increased. We describe a case with ST segment elevation on admission ECG, and coronary angiography was normal. Cardiac magnetic resonance with myocardial delayed enhancement sequences is a non-invasive alternative for diagnosing myocarditis. PMID:24711464

  7. National registry of myocardial infarction

    OpenAIRE

    Amin Daemi; Mehdi Jafari

    2016-01-01

    The Registry of Myocardial Infarctions (MI Registry) is a national registry in Iran that collects and reports the data on myocardial infarctions. Its main advantage is that it covers the whole country and is mandatory for hospitals to register the MI cases in it. Then, the qualified individuals at the provincial and national levels can get intended reports and make appropriate decisions. Such reports, further to the policy makers and managers, can be very valuable for researchers. The regi...

  8. Development of a J-estimation scheme for internal circumferential and axial surface cracks in elbows

    International Nuclear Information System (INIS)

    This report summarizes efforts to develop elastic and elastic-plastic fracture mechanics analyses for internal surface cracks in elbows. The analyses involved development of a GE/EPRI type J-estimation scheme which requires an elastic and fully plastic contribution to crack-driving force in terms of the J-integral parameter. The elastic analyses require the development of F-function values to relate the Je term to applied loads. Similarly, the fully plastic analyses require the development of h-functions to relate the Jp term to the applied loads. The F- and h-functions were determined from a matrix of finite element analyses. To minimize the cost of the analyses, three-dimensional ABAQUS finite element analyses were compared to a simpler finite element technique called the line-spring method. The line-spring method provides a significant computational savings over the full three-dimensional analysis. The comparison showed excellent agreement between the line-spring and three-dimensional analysis. This experience was consistent with comparisons with circumferential surface-crack analyses in straight pipes during the NRC's Short Cracks in Piping and Piping Welds program

  9. Fracture behavior evaluations for ferritic steel piping with circumferential double flaws on the inner surface

    International Nuclear Information System (INIS)

    Methods for assessing the structural integrity of nuclear components having some flaws are provided in the Rules on Fitness-for-Service for Nuclear Power Plants of the JSME code (JSME FFS code). Although the JSME FFS code provides such methods for piping with a single flaw, it does not describe any method for fracture assessment of piping with multiple flaws including flaw coalescence criteria. Some investigations on the fracture behavior of mainly austenitic stainless steel piping with multiple flaws, whose fracture mode is plastic collapse, have recently been reported and fracture assessment methods have been proposed. In the present study, fracture tests and analyses of carbon steel piping with a single and two circumferential flaw(s) on the inner surface were conducted to investigate a method for fracture assessment of ferritic steel piping with multiple flaws. It was found that fracture assessment based on the twice elastic slope method and the plastic collapse mechanism gave inadequate results for a large single flaw. Including this case, two kinds of elastic–plastic fracture assessment method, one using the Z-factor in the JSME FFS code and the other by ductile instability analysis, gave conservative estimates of fracture strength even when the structural factor SF was not considered (i.e. SF = 1)

  10. The Prognostic Value of Circumferential Resection Margin Involvement in Patients with Extraperitoneal Rectal Cancer.

    Science.gov (United States)

    Shin, Dong Woo; Shin, Jin Yong; Oh, Sung Jin; Park, Jong Kwon; Yu, Hyeon; Ahn, Min Sung; Bae, Ki Beom; Hong, Kwan Hee; Ji, Yong Il

    2016-04-01

    The prognostic influence of circumferential resection margin (CRM) status in extraperitoneal rectal cancer probably differs from that of intraperitoneal rectal cancer because of its different anatomical and biological behaviors. However, previous reports have not provided the data focused on extraperitoneal rectal cancer. Therefore, the aim of this study was to examine the prognostic significance of the CRM status in patients with extraperitoneal rectal cancer. From January 2005 to December 2008, 248 patients were treated for extraperitoneal rectal cancer and enrolled in a prospectively collected database. Extraperitoneal rectal cancer was defined based on tumors located below the anterior peritoneal reflection, as determined intraoperatively by a surgeon. Cox model was used for multivariate analysis to examine risk factors of recurrence and mortality in the 248 patients, and multivariate logistic regression analysis was performed to identify predictors of recurrence and mortality in 135 patients with T3 rectal cancer. CRM involvement for extraperitoneal rectal cancer was present in 29 (11.7%) of the 248 patients, and was the identified predictor of local recurrence, overall recurrence, and death by multivariate Cox analysis. In the 135 patients with T3 cancer, CRM involvement was found to be associated with higher probability of local recurrence and mortality. In extraperitoneal rectal cancer, CRM involvement is an independent risk factor of recurrence and survival. Based on the results of the present study, it seems that CRM involvement in extraperitoneal rectal cancer is considered an indicator for (neo)adjuvant therapy rather than conventional TN status. PMID:27097629

  11. The stability of through-wall circumferential cracks in cylindrical pipes subjected to bending loads

    International Nuclear Information System (INIS)

    Tada, Paris and Gamble have used the tearing modulus approach to show that when a circumferential through-wall crack exists in a 304 SS circular cylindrical pipe, and the pipe is subjected to an applied bending moment, then crack growth requires the rotation at the pipe-ends to be increased, (i.e. crack growth is stable), unless the pipe length is unduly large. On this basis it was concluded that unstable fracture is unlikely to occur in BWR SS piping, when the system is designed in accord with the ASME Code load levels for normal operation and anticipated transients. The Tada-Paris-Gamble analysis focuses on the inter-relation between instability and the onset of crack extension, and does not specifically consider the possibility that a crack might become unstable after some stable crack extension. The paper addresses this aspect of the crack stability problem using a crack tip opening angle criterion for crack extension, which has similarities with the tearing modulus approach. The results show that unstable fracture should not occur even after some stable crack extension, again provided that the pipe length is not unduly large. In other words, guillotine failure of a pipe in a BWR system is unlikely, even though the ASME Code limiting stress levels as might be exceeded, as may be the case with a very severe earthquake. (orig./HP)

  12. J-integral study of elbow with circumferential through-wall crack

    International Nuclear Information System (INIS)

    The elbow is an important component in nuclear piping system, and also is the location where crack easily occurrs. To ensure the structural integrity of the nuclear piping system, a fracture mechanics analysis for the cracked elbows will be necessarily performed. In this paper, the 3-D elastic-plastic fracture mechanics methodology is used to study the elbows with a through-wall circumferential crack by using of ABAQUS software, and some numerical results for J-integral are obtained. the calculated results show that the influence of bending radius on J-integral is not associated with locations of the cracks. It is, however, intimate to sizes of the cracks. The effects on the J-integral for elbows with small size of cracks are insignificant. As to the J-integral for elbows with large size of cracks, the value of the J-integral is reduced as the Rb/R ratio of bending radii increases. In the case that the end rotating angle is kept unchanged, the relation between R/t ratio and J-integral is approximately linear, i.e., a linear interpolation can be used. (authors)

  13. Leak before break behaviour of austenitic and ferritic pipes containing circumferential defects

    Energy Technology Data Exchange (ETDEWEB)

    Stadtmueller, W.; Sturm, D.

    1997-04-01

    Several research projects carried out at MPA Stuttgart to investigate the Leak-before-Break (LBB) behavior of safety relevant pressure bearing components are summarized. Results presented relate to pipes containing circumferential defects subjected to internal pressure and external bending loading. An overview of the experimentally determined results for ferritic components is presented. For components containing postulated or actual defects, the dependence of the critical loading limit on the defect size is shown in the form of LBB curves. These are determined experimentally and/or by calculation for through-wall slits, and represent the boundary curve between leakage and massive fracture. For surface defects and a given bending moment and internal pressure, no fracture will occur if the length at leakage remains smaller than the critical defect length given by the LBB curve for through-wall defects. The predictive capability of engineering calculational methods are presented by way of example. The investigation programs currently underway, testing techniques, and initial results are outlined.

  14. Residual Stresses Due to Circumferential Girth Welding of Austenitic Stainless Steel Pipes

    Science.gov (United States)

    Tarak, Farzan

    Welding, as a joining method in fabrication of engineering products and structural elements, has a direct influence on thermo-mechanical behavior of components in numerous structural applications. Since these thermo-mechanical behaviors have a major role in the life of welding components, predicting thermo-mechanical effects of welding is a major factor in designing of welding components. One of the major of these effects is generation of residual stresses due to welding. These residual stresses are not the causes of failure in the components solely, but they will add to external loads and stresses in operating time. Since, experimental methods are time consuming and expensive, computational simulation of welding process is an effective method to calculate these residual stresses. This investigation focuses on the evaluation of residual stresses and distortions due to circumferential girth welding of austenitic stainless steel pipes using the commercial finite element software ESI Visual-Environment and SYSWELDRTM to simulate welding process. Of particular importance is the comparison of results from three different types of mechanics models: 1) Axisymmetric, 2) Shell, and 3) Full 3-D.

  15. Interactions of a propeller with a stator-induced circumferentially varying flow

    Energy Technology Data Exchange (ETDEWEB)

    Farnsworth, John [Rensselaer Polytechnic Institute, Mechanical Aerospace and Nuclear Engineering, Troy, NY (United States); US Air Force Academy, Department of Aeronautics, Colorado Springs, CO (United States); Amitay, Michael [Rensselaer Polytechnic Institute, Mechanical Aerospace and Nuclear Engineering, Troy, NY (United States); Rensselaer Polytechnic Institute, Center for Flow Physics and Control (CeFPaC), Troy, NY (United States); Beal, David; Huyer, Stephen A. [Naval Undersea Warfare Center, Division, Vehicle Dynamics and Signature Control, Newport, RI (United States)

    2012-02-15

    The interactions of a circumferentially varying stator cascade and a downstream fixed pitch propeller were investigated experimentally. The global performance of the components and the coupled system were systematically investigated through force and moment measurements on the propulsor model in a water tunnel. In addition, the wake of the cyclic stator cascade with and without the propeller was investigated downstream from a propulsor model using the Stereoscopic PIV technique. A cyclic distribution of the stators' deflections resulted in non-axisymmetric distributions of the flow field downstream of the stator array. The stator distribution alone produced a significant side force that increased linearly with stator pitch amplitude. When a propeller was incorporated downstream from the cyclic cascade, the side force from the stator cascade was reduced, but a small normal force and pitching moment were created. The generation of these secondary forces and moments can be related to the redistribution of the tangential flow from the cyclic cascade into the axial direction by the retreating and advancing blade states of the fixed pitch propeller. (orig.)

  16. Simultaneously Combined Anterior-Posterior Approaches for Subaxial Cervical Circumferential Reconstruction in a Sitting Position.

    Science.gov (United States)

    Han, Yue; Xia, Qun; Hu, Yong-cheng; Zhang, Ji-dong; Lan, Jie; Ma, Xin-long

    2015-11-01

    The purpose of this article is to introduce and analyze the feasibility of simultaneously combined anterior-posterior approaches for subaxial cervical circumferential reconstruction in sitting position. A retrospective case review was performed for above surgery procedure. A 79-year-old man was confirmed subaxial cervical fracture and dislocation with facet locked by radiological examination, and the involved levels were C5-6. According to American Spinal Injury Association (ASIA) classification, the impairment scale was grade B. And the Subaxial Cervical Spine Injury and Severity Score (SLIC) were 9. The patient was restricted in sitting position with traction on a halo in extension to immobilize the head during the operation. A posterior laminectomy and pedicle screws insertion to the involved cervical spine was performed firstly. And then the anterior discectomy and strut graft were accomplished through an anterior cervical approach. The final fixation was finished by clamping the strut graft with pedicle screw system. Total blood loss was 600 ml and the total operating time was 150 min. The patient was followed up for 6 months. The symptom of neck pain improved distinctly and no evidence about implant failure was noted. Neurological status improvement was confirmed and the ASIA scale was improved to grade C. We believed that the simultaneously combined anterior-posterior approach in sitting position was safe and more advantageous for appropriate cases. PMID:26790982

  17. Stress-intensity-factor influence coefficients for axial and circumferential flaws in reactor pressure vessels

    International Nuclear Information System (INIS)

    Weight-function techniques in linear elastic fracture mechanics utilize stress-intensity-factor influence coefficients K* and superposition principles to compute stress intensity factors. This paper presents influence coefficients for two flaw geometries often employed in fracture analyses of reactor pressure vessels: (1) infinitely long, axial, inside-surface flaws and (2) 360 degrees, circumferential, inside-surface flaws. Calculations were performed using ABAQUS, a nuclear quality assurance (NQA-1) certified finite-element program which employs a highly accurate crack extension technique for the computation of theJ-integral. Influence coefficients are computed for flaw depths in the range 0.01 ≤ a/T ≤ 0.9 with particular emphasis on shallow flaws (a/T ≤ 0. 1). This study addresses vessels having R/T = 10 which is appropriate for most PWRs in USA. The influence coefficients have been implemented in the FAVOR fracture-mechanics code currently being developed under the NRC-funded HSST Program at ORNL

  18. Myocardial scintigraphy in the diagnosis of myocardial contusion

    International Nuclear Information System (INIS)

    To assess the clinical value of a new fatty acid imaging tracer, 123I-β-methyl iodophenyl pentadecanoic acid (BMIPP), I-BMIPP and thallium-201 (Tl) dual imaging was performed at rest in fifteen patients with mild blunt chest trauma (mean AIS thoracic 1.4±0.51, mean ISS 6.47±3.50, mean RTS 7.69±0.43). All patients were prospectively evaluated on the basis of serial electrocardiograms (ECG) and cardiac enzyme studies (total CPK). Tl and BMIPP dual scintigrams were performed within 10 days following admission. SPECT images were divided into seven segments, and the segmental images were visually scored according to tracer uptake on a 3 (severely decreased tracer uptake) to 0 (normal) scale. Nine patients had scintigraphic defects and were considered to have a myocardial contusion. ECG findings, AIS, ISS, and CPK levels failed to distinguish between scintigraphically positive patients and scintigraphically negative patients. Five of the 14 hypoperfused segments on BMIPP imaging, showed normal Tl uptake, one showed lower BMIPP uptake than Tl, and the remaining eight showed similar distribution of both tracers. The mismatch between tracer uptake on BMIPP images and Tl images was thought to reflect impaired myocardial fatty acid metabolism. Thus, mild blunt chest trauma results in a higher frequency of traumatic myocardial injury than previously recognized, and BMIPP is a promising radio-pharmaceutical for evaluating impaired myocardial fatty acid metabolism in patients with myocardial contusion. (author)

  19. Radio-isotopic myocardial study

    International Nuclear Information System (INIS)

    The non invasive study of the myocardium with radio-isotopes is effected either with radio-elements labeling on recently infarcted myocardium, such as PYP Tc 99m, or after I.V. injection of Tl 201 extracted by normal myocardium or after I.V. injection of radio-element which study the myocardial metabolism. The fixation of PYP Tc 99m, bordering that of calcium, appears 24 hours after the onset of the myocardial infarction; then it reduces and disappears a week later; its persistency gives evidence of an evolution to ventricular anevrism. The relatively low sensitivity and specificity of this test should induce to reserve if for precise cases. 201 Tl realizes a map of the myocardial flow because this radio-isotope reflects with damping the variations of coronary flow. The scintigraphy is made either after stress test or after I.V. injection of dipyridamole, and the sensitivity and specificity of the test is better than electrocardiographic exercise stress test. The predictive value of the test for a patient highly depends of the prevalence of the coronary disease for this patient; however the results of Tl scintigraphy are far from an ideal test; quantitative or semi-quantitative analysis of the image compared to the analogical image seems to improve sensitivity for detection of coronary disease. After myocardial infarction, its best use is to detect a left anterior descending stenosis after posterior or inferior infarction. Among the possible radio-elements of myocardial metabolism, scintigraphy with fatty acids opens interesting prospects for the study of the myocardial clearance of the radio-isotope, that reflects the global or regional myocardial metabolism

  20. Mismatch Limit Load Analyses for V-groove Welded Pipe with Through-wall Circumferential Defect in Centre of Weld

    International Nuclear Information System (INIS)

    The present work reports the mismatch limit loads for a V-groove welded pipe for a circumferential crack using finite element (FE) analyses. To integrate the effect of groove angles on mismatch limit loads, one geometry related slenderness parameter was modified by relevant geometric parameters including the groove angle, crack depth, and root opening based on plastic deformation patterns in the theory of plasticity. Circumferential through-wall cracks are located at the centre of the weldments with two different groove angles (45 .deg., 90 .deg.). With regard to the loading conditions, axial (longitudinal) tension and bending are applied for all cases. For the parent and weld metal, elastic-perfectly plastic materials are considered to simulate and analyze under- and over-matching conditions in plasticity. The overall results from the proposed solutions are found to be similar to the FE results

  1. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    OpenAIRE

    Iannicelli, Elsa; Di Renzo, Sara; ferri, mario; Pilozzi, Emanuela; Di Girolamo, Marco; Sapori, Alessandra; Ziparo, Vincenzo; David, Vincenzo

    2014-01-01

    Objective To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Materials and Methods Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy...

  2. CAD of myocardial perfusion

    Science.gov (United States)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

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

  3. Myocardial infarction in children: Two interesting cases

    Directory of Open Access Journals (Sweden)

    Suryawanshi Suresh

    2011-01-01

    Full Text Available Myocardial infarction in children is extremely rare and can have various etiologies. The following two case reports highlight rare but important causes of myocardial infarction in children.

  4. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Sujatha. M

    2015-12-01

    Full Text Available Introduction: The segment of epicardial coronary artery that traverses intramurally through the myocardium and bridged by a bunch of cardiac muscle fibers is called tunneled artery or intramural artery. The band of cardiac muscle fibers passing over the tunneled artery segment is named as myocardial bridge. During angiography milking effect is observed during systole due to the external pressure of muscle fibers on the tunneled artery that leads to narrowing of vessel lumen and further ischemia. Materials & Methods: It is a prospective study performed from 2012- 2015 in cardiac centers available around Tirupati, Andhra Pradesh, South India. A total number of 2015 adult patients who underwent diagnostic coronary angiography were evaluated to detect myocardial bridges. With the informed consent the relevant data was collected from the patients and analyzed. Results: The prevalence of myocardial bridges was 3.17%. Among the 2015 patients 70.7% are males and 29.2% are females. Among 64 myocardial bridge positive cases 62.5% were male and 37.5% were female patients. Regarding coronary dominance 84% were right dominant and 14.4% were left dominant and 1.6% are balanced. The percentage incidence of myocardial bridging according to dominance was 3.01% for right dominant patients, 4.12% for left dominant patients and 3.1% for balanced dominant patients. In all the myocardial bridge positive cases they were located on the left anterior descending artery (LAD. According to diagnosis the patients with normal coronaries were 22.6%, patients with MILD CAD were 17.9%, patients with single vessel disease were 23.4%, patients with two vessel disease were 14.7% and the patients with triple vessel disease were 21.3%. The 64 myocardial bridging cases were grouped in to three groups according to their age. Incidence of double bridges was observed in 3 cases of which 66.7% males & 33.3% in females. Conclusion: These results show that Andhra Pradesh population are

  5. Different bone regeneration patterns in periimplant circumferential gap defects grafted with two types of osteoconductive biomaterial.

    Science.gov (United States)

    Lee, Jung-Seok; Sohn, Joo-Yeon; Lim, Hyun-Chang; Jung, Ui-Won; Choi, Seong-Ho

    2016-08-01

    This study aimed to determine healing patterns in periimplant gap defect grafted with demineralized bovine bone mineral (DBBM) and porous titanium granules (PTG), which are known to induce a minimal tissue reaction and to undergo minimal biodegradation in healing process. Experiments were performed using a standardized periimplant gap-defect model in dogs with two observational periods: 4 and 8 weeks. Circumferential defects were surgically induced around dental implants on unilateral mandibles in five dogs, and collagen barrier membranes were placed over the DBBM and PTG grafts at two experimental sites and over a nongrafted site. Four weeks later, the same procedures were performed on the contralateral mandible, and the animals allowed to heal for a further 4 weeks, after which they were sacrificed and their mandibles with graft/control sites harvested for histologic evaluation. Both types of grafted biomaterials significantly enhanced the defect fill with newly formed bone, but the bone-to-implant contact (BIC) was significantly increased only at sites that had been grafted with DBBM. The two experimental sites exhibited different healing patterns, with new bone formation being observed on the surface of the DBBM particles throughout the defect, while there was no de novo bone formation on the PTG surface, but rather appositional bone growth from the base and lateral walls of the defect. It has been suggested that gap-defect filling with DBBM around dental implants may enhance both BIC and defect fill; however, the present findings show that defect grafting with PTG enhances only defect fill and not BIC. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1202-1209, 2016. PMID:26087247

  6. Early-phase changes of P-wave characteristics after circumferential pulmonary vein isolation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liang; JIANG Wei-feng; ZHOU Li; LIU Xu

    2013-01-01

    Background Circumferential pulmonary vein isolation (CPVI),as the basal ablation strategy for treating atrial fibrillation (AF),not only isolates the connection between the left atrium (LA) and the pulmonary veins (PVs),but also induces extensive atrial endocardia damage.This could have an effect on the sinus pulse conduction in the LA and subsequently result in changes of P-wave characteristics of surface electrocardiogram (ECG).Methods Fifty consecutive patients underwent CPVI for symptomatic drug-refractory paroxysmal AF.The 12-lead ECGs were recorded one day before CPVI and seven days after CPVI at sinus rhythm by a standard resting ECG device.Measured characteristics of the P-wave consisted of P-wave duration (PWD),P-wave amplitude (PWA),P-wave polarity (PWP),P-wave notch,P-wave dispersion and P-wave index.Results After CPVI,a prevalent decrease of PWD,PWA,and P-wave dispersion was observed; a transition of P-wave polarity was observed in the leads of Ⅲ,aVL and aVF.The rate of P-wave notch decreased significantly in all leads,especially in the leads of Ⅱ,Ⅲ,aVF and V3.Patients with sinus rhythm had a shorter P-wave dispersion and P-wave index and had a lower rate of P-wave notch compared with the patients with recurrent atrial tachyarrhythmia.Conclusion Observations from using the surface ECG showed that CPVI has instant effects on the electrical conduction in the LA,and several changes of P-wave characteristics associated with development of AF are improved by CPVI.

  7. Single-stage Posterior Spondylectomy,Circumferential Decompression and Reconstruction Using Mesh Cage for Spinal Tumors

    Institute of Scientific and Technical Information of China (English)

    Yong Zhu; Hong Zhao; Giu-xing Qiu; Jian-guo Zhang; Ye Tian; Shu-gang Li; Suo-mao Yuan

    2009-01-01

    Objective To explore the feasibility and clinical results of circumferential decompression and threecolumn reconstruction through single-stage posterior transpedicular approach for spinal tumor treatment.Methods Totally,24 patients with spinal tumor underwent tumor resection and spinal reconstruction through single-stage posterior transpedicular approach.Preoperatively,according to the Frankel classification,12 patients were grade E,9 grade D,and 3 grade C.Anterior column was reconstructed with non-expandable titanium cages.Posterior segmental instrumentation was used to maintain the stability of spine in all cases.Anterior and posterolateral fusion was performed with autograft and allogenic bone.The following data were followed up in these patients:deformity angle,local recurrence,neurological function,and spinal bony fusion.Results The average operating time and blood loss was 5.6 hours and 3 400 ml respectively.No intraoperative and postoperative complications were observed in this group.Postoperatively,21 patients were Frankel grade E,2 grade D,and 1 grade C.Four patients reported significant functional restoration and twenty patients reported complete resolution of pain.At follow-up(range,6-42 months),implant failure or recurrent neurological symptoms was not found.Conclusions The tumor resection and spinal reconstruction through single-stage posterior transpedicular approach is a safe and effective technique for the treatment of spinal tumor.It can fully decompress the neurological structures,correct the kyphosis,and achieve early weight-bearing.This technique can improve life quality for the patients with spinal tumor.

  8. Quantification of myocardial infarct size by thallium-201 single-photon emission computed tomography: experimental validation in the dog

    International Nuclear Information System (INIS)

    To evaluate the potential advantages of thallium-201 (201T1) single-photon emission computerized tomography (SPECT) to assess myocardial infarct size in the experimental animal, six normal dogs and 14 dogs with 6 to 8 hr closed-chest coronary occlusion (eight left anterior descending and six left circumflex) were studied. Ten minutes after intravenous administration of 2 mCi of 201T1, 30 projections were obtained over 1800. The dogs were killed and their hearts sliced and stained by triphenyl tetrazolium chloride (TTC). Pathologic infarct size was calculated for each slice and for the entire left ventricular myocardium as percent weight. Tomograms were quantified by automatically generating maximum-count circumferential profiles, which were compared with normal limit profiles derived from the six normal dogs. Tomographic infarct size was defined as the percentage of circumferential points falling below normal for each tomogram. SPECT and TTC infarct size on 71 slices correlated highly (mean +/- SD 27.9 +/- 23.4% and 26.7 +/- 25.3%, respectively; r = .93, p less than .001, SEE = 9.4%). To determine SPECT infarct size as percent total left ventricular myocardial weight, infarct sizes from each slice were added to one another after each was multiplied by a coefficient that reflected the contribution of that slice to the total left ventricular weight. SPECT and TTC infarct size for the entire left ventricle correlated closely (mean +/- SD 20.5 +/- 7.6% and 19.3 +/- 8.3%, respectively; r = .86, p less than .001, SEE = 4.5%). It is concluded that 201T1 SPECT is a valid method for the noninvasive assessment of experimental myocardial infarct size

  9. Acute Myocardial Infarction Due To Electrical Injury

    OpenAIRE

    Uzkeser M et al.

    2011-01-01

    Rhythm abnormalities (conduction defects, tachycardia, and arrhythmia)due to electric shock are common. Rarely, myocardial infarction may beseen in these patients. This situation is generally caused by coronaryartery vasospasm and direct myocardial damage. In this report, wepresent a rare case of myocardial infarction due to electric shock.

  10. Influence of corrosion on the strain profiles of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, G.; Newhook, J.P. [Dalhousie Univ., Halifax, NS (Canada). Dept. of Civil Engineering

    2003-07-01

    Natural gas, oil and petroleum products in Canada are transported by pipelines, many of which are over a quarter of a century old. A major challenge facing the petroleum industry is corrosion of pipelines. To minimize the probability of a line failure, pipeline owners adhere to strict inspection and maintenance schedules. Maintenance, using current in-line inspection tools, necessitates the transmission lines to be shut down. This paper described an alternative way to detect pipeline corrosion, using a numerical investigation of the change in strain profile of a corroded pipeline under internal pressure. A finite element model of a typical thin-walled pressure vessel was created under linear elastic axisymmetric conditions. The thinning of the wall simulated corrosion. The authors studied the change in longitudinal and circumferential strain under the same operating pressure. A parametric study was performed using a wide array of corrosion geometries and depths. A distinct and detectable change in strain for specific degrees of corrosion was identified. An increase in the amount of corrosion resulted in an increase in the rate of circumferential and longitudinal strains. The geometry of the corrosion profile had a big influence on the slope of the strain gradient. According to the initial evaluation, it appears feasible to design a structural health monitoring system using continuous strain monitoring as its basis, but additional studies are required to model actual in-situ pipeline conditions, as well as an assessment of non-linear response. 5 refs., 2 tabs., 7 figs.

  11. Mortality rate in type 2 myocardial infarction

    DEFF Research Database (Denmark)

    Saaby, Lotte; Poulsen, Tina Svenstrup; Diederichsen, Axel Cosmus Pyndt;

    2014-01-01

    BACKGROUND: The classification of myocardial infarction into 5 types was introduced in 2007. The prognostic impact of this universal definition, with particular focus on type 2 myocardial infarction, has not been studied prospectively in unselected hospital patients. METHODS: During a 1-year period......, all hospitalized patients having cardiac troponin I measured were considered. The diagnosis of a myocardial infarction was according to the universal definition, and specified criteria were used in the classification of type 2 myocardial infarction. Follow-up was at least 1 year, with mortality as the...... 2 myocardial infarction. CONCLUSIONS: Mortality in patients with type 2 myocardial infarction is high, reaching approximately 50% after 2 years. Further descriptive and survival studies are needed to improve the scientific evidence on which treatment of type 2 myocardial infarction is based....

  12. Procedures for the strain based assessment of pipeline dents

    International Nuclear Information System (INIS)

    A criterion for strain-based assessment of dents in gas pipelines has been recently proposed in the ASME B31.8 code. This work initially presents a critical review of the equations for estimating strains presented in Appendix R of that code. Next, a procedure based on B-spline curves is presented that interpolates dent geometry from data measured by in-line inspection (ILI) tools and evaluates strain components. The paper proceeds with studies to assess the influence of the ILI tool resolution and positioning on the estimation of the circumferential bending strain. Finally, the evaluation of longitudinal membrane strains is assessed by taking two alternative definitions for dent length that enters in the formula proposed in Appendix R of the aforementioned code, and comparing with results provided by Finite Element analyses. The comparison suggests that directions on how to measure the dent length might be incorporated in a revision of the ASME B31.8 Code.

  13. Design and Testing of the Strain Transducer for Measuring Deformations of Pipelines Operating in the Mining-deformable Ground Environment

    Science.gov (United States)

    Gawedzki, Waclaw; Tarnowski, Jerzy

    2015-10-01

    Design and laboratory test results of the strain transducer intended for monitoring and assessing stress states of pipelines sited in mining areas are presented in this paper. This transducer allows measuring strains of pipelines subjected to external forces - being the mining operations effect. Pipeline strains can have a direct influence on a tightness loss and penetration of the transported fluid into the environment. The original strain gauge transducer was proposed for performing measurements of strains. It allows measuring circumferential strains and determining the value and direction of the main longitudinal strain. This strain is determined on the basis of measuring component longitudinal strains originating from axial forces and the resultant bending moment. The main purpose of investigations was the experimental verification of the possibility of applying the strain transducer for measuring strains of polyethylene pipelines. The obtained results of the transducer subjected to influences of tensile and compression forces are presented and tests of relaxation properties of polyethylene are performed.

  14. Design and Testing of the Strain Transducer for Measuring Deformations of Pipelines Operating in the Mining-deformable Ground Environment

    Directory of Open Access Journals (Sweden)

    Gawedzki Waclaw

    2015-10-01

    Full Text Available Design and laboratory test results of the strain transducer intended for monitoring and assessing stress states of pipelines sited in mining areas are presented in this paper. This transducer allows measuring strains of pipelines subjected to external forces - being the mining operations effect. Pipeline strains can have a direct influence on a tightness loss and penetration of the transported fluid into the environment. The original strain gauge transducer was proposed for performing measurements of strains. It allows measuring circumferential strains and determining the value and direction of the main longitudinal strain. This strain is determined on the basis of measuring component longitudinal strains originating from axial forces and the resultant bending moment. The main purpose of investigations was the experimental verification of the possibility of applying the strain transducer for measuring strains of polyethylene pipelines. The obtained results of the transducer subjected to influences of tensile and compression forces are presented and tests of relaxation properties of polyethylene are performed.

  15. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  16. Dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

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

  17. Myocardial ischemia in Kawasaki disease

    International Nuclear Information System (INIS)

    The detection of myocardial ischemia is essential for evaluation of patients with Kawasaki disease, especially who have had coronary artery lesions. To evaluate the clinical efficacy of Tl-201 single photon emission computed tomography (SPECT) after dipyridamole infusion (maximum dose 0.70 mg/kg) for detecting myocardial ischemia, 44 patients with Kawasaki disease aged 7.7±4.8 years at the study and 10 age matched controls were observed. In the Kawasaki disease group, significant coronary artery stenosis was observed in 14, coronary aneurysm without stenosis in 18, the regression of the coronary aneurysms in 2 and without coronary lesions in 10 patients. In 24 of 44 patients, treadmill exercise stress test was also performed at the same period. Myocardial ischemic changes were observed in 11 patients, all combined with significant coronary artery stenosis. The sensitivity of SPECT for detection of overall coronary stenosis was 79%, coronary that of treadmill exercise test was only 33% (p<0.001). Furthermore, among the patients having significant coronary stenosis, the severity score was significantly elevated in patients who had electrocardiographic abnormal Q wave compared to those without abnormal Q wave (51.0±38.8 versus 20.0±12.1, p<0.05). These data suggest that the pharmacological stress scintigraphy using dipyridamole injection provides not only the accurate detection but quantitative evaluation of myocardial ischemia in these patients. This noninvasive technique may become one of the most useful index for detection and follow-up of myocardial ischemia in Kawasaki disease. (author)

  18. Myocardial ischemia and angina pectoris

    International Nuclear Information System (INIS)

    Ambulatory monitoring of ST segment changes was performed in 60 patients presenting with angina, positive ECG stress tests and coronary artery disease, 85% of ischemic ECG events were asymptomatic, 37% occurred with no increase in heart rate and 15% of episodes either lasted 20 minutes or more or fluctuated in severity. A controlled pilot study in ten patients showed depression. Radionuclide studies in 50 patients with angina and coronary artery disease have shown that stress (i.e., atrial pacing) produced different patterns of disturbed regional myocardial perfusion related to the patient's exercise capacity and eventually leading to a decrease in regional myocardial perfusion during the ischemic episode. ST segment depression appeared only after the decrease in regional myocardial perfusion. These findings combined with past research suggest that patients with angina and coronary artery disease can suffer frequent asymptomatic disturbances of the regional myocardial perfusion. The frequency of these episodes and the time course for the recovery of the metabolic consequences mean that segments of ventricular myocardium may be constantly abnormal. The relative importance of changes in coronary tone and malfunction of platelets in the diseased coronary tree needs to be examined in clinical research. Pilot studies of antiplatelet agents have shown a significant beneficial effect on episodes of ischemia occurring at night and those occurring without any increase in heart rate. The techniques and observations in these patients with coronary artery disease all suggest that acute transient regional myocardial ischemia is caused by a variety of mechnisms. Further research using objective methods is required to discover the causes of ischemia and to rationalize treatment. (orig./MG)

  19. Study progress of cardiac MRI technology in assessment of myocardial viability after myocardial infarction

    International Nuclear Information System (INIS)

    Acute myocardial infarction (AMI) is one of the most common diseases that cause disability and death around the world. Correctly and effectively assessing the myocardial viability after myocardial infarction can reduce the disabled rate and mortality rate. At present, many methods could be used to assess myocardial viability. The cardiac magnetic resonance imaging (CMR) technology has a lot of advantages compared to other methods. In this paper, we reviewed the research progress of CMR in assessment of myocardial viability after myocardial infarction, and compared CMR with other technologies. (authors)

  20. Clinical studies of regional myocardial thallium-201 washout rate in hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Yutaka; Genda, Akira; Mizuno, Sumio; Shimizu, Masami; Nituta, Yutaka; Takeda, Ryoyu; Bunko, Hisashi; Hisada, Kin-ichi

    1987-02-01

    A trial was undertaken to elucidate the cause of disproportional hypertrophy (DPH) in hypertrophic cardiomyopathy (HCM). Twenty-eight HCM patients in whom coronary arteriography was normal and 10 normal volunteers underwent thallium-201 myocardial imaging during exercise. Based on ventriculographic findings, the sites of DPH were classified as interventricular septum (IVS), IVS-apical anterior wall, apical anterior wall, and whole wall. Washout rate (WR) and early uptake rate (UT) were obtained by analyzing circumferential profiles from Tl-201 images. The mean UT was significantly low from the apex to the bottom of the anterior ventricular septum, and significantly high in the basal portion of the anterior ventricular septum, as compared with the control group. The mean WR was significantly decreased in all the segments in any type of HCM group. Decreased WR was also observed in the site showing increased UT. Seventeen patients (61%) showed abnormally decreased UT and/or WR for 25 segments. Twenty-one (84%) segments had a decrease in WR only, 16 of which had been specifically thickened. In 20 patients with normal UT, WR was significantly decreased in the thinnest postero-lateral wall. The results indicate that HCM is characterized by decreased WR in the DPH sites. It is supposed that damaged coronary microcirculation may be a contributing factor to the decrease in WR and UT, and disturbed metabolism in myocardial cells may be involved in the sole decrease of WR as well. Both disturbances are considered closely related to the cause of DPH. (Namekawa, K.).

  1. Value of the magnetic resonance imaging in the assessment of the circumferential resection margin (CRM) in patients with rectal cancer

    International Nuclear Information System (INIS)

    Purpose: To determine whether magnetic resonance imaging (MRI) can predict tumor involvement of the circumferential resection margin (CRM) in patients with rectal cancer. Materials and methods: Between april 2005 and march 2008, 70 consecutive patients (mean age 64, range 34-78 years), 40 F and 30 M, with endoscopy and biopsy- proven middle and lower rectal cancer. Non contrast enhanced MRI was performed on a Siemens Avanto 1.5 T. A phased array coil was used and T2 weighted thin section sequences (TR/TE 4200/88, slice thickness 3mm, gap 0, matrix 256 x 256, field of view 150 x 150 mm) were performed in axial, sagittal and coronal orientations. Patients received a 150 ml glycerin enema before examination. No air insufflations or intramuscular antispasmodic was used. The shortest distance from the tumor edge to the circumferential margin was measured. A distance ≤ ?2 mm, analyzed in axial slices, was considered as definition of circumferential margin involvement. Results: The CRM was 2 mm in both MRI and histopathological findings in 26 patients. In 8 cases the CRM was shorter on MRI than in histopathological sections. In 32 patients the CRM was respected in both exams and 4 patients were considered positive on histopathological findings but negative in MRI. The sensitivity, specificity, positive and negative predictive values for prediction of tumor involvement of CRM were 86%, 80%, 76% and 88%, respectively. Conclusions: MRI gives reliable information on tumor involvement of the CRM in patients with rectal cancer. This may provide accurate identification of an important prognostic risk factor in patients prior to surgical treatment. (authors)

  2. Contribution to the Evaluation of the Circumferentially-Cracked Round Bar for Fracture Toughness Determination of Reactor Pressure

    International Nuclear Information System (INIS)

    The subject of this PhD dissertation is the use of the Circumferentially-Cracked Round Bar (CRB) for fracture toughness measurements. The main advantages of CRB are the relatively small size requirements of the testing specimens, the low cost to machine the specimen, the rotating bending fatigue allowing for easy precracking of specimens, the use of standard tensile test fixture and the axisymmetry of the specimen that avoids time consuming 3D finite element calculations. An in-depth study of the most widely used precracking technique for CRB, namely the rotating bending fatigue, is made

  3. Fracture Toughness (K1C) evaluation for dual phase medium carbon low alloy steels using circumferential notched tensile (CNT) specimens

    OpenAIRE

    Kenneth Kanayo Alaneme

    2011-01-01

    The fracture behavior of dual phase medium carbon low alloy steels produced using two different chemical compositions (A - 0.34C, 0.75Mn, 0.12Cr, 0.13Ni steel and B - 0.3C, 0.97Mn, 0.15Cr steel) was investigated using circumferential notched tensile (CNT) specimens. Intercritical treatments were performed on samples with composition A by 1) austenitizing at 860 °C for 1 hour cooling in air, then treating at 770 °C for 30 minutes before oil quenching; 2) austenitizing at 860 °C for 1 hour quen...

  4. Influence of the circumferential speed of a resin bond grinding wheel on the properties of a ground aspheric surface

    Czech Academy of Sciences Publication Activity Database

    Matoušek, O.; Tomka, David; Procháska, František; Polák, Jaroslav

    Vol. 9442. Bellingham: SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Kovačičinová, J.; Vít, T.), 94420T-94420T. (SPIE). ISBN 978-1-62841-557-5. ISSN 0277-786X. [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Aspheric grinding * resin bond * tool circumferential speed optimization Subject RIV: JP - Industrial Processing http://spie.org/Publications/Proceedings/Paper/10.1117/12.2175630

  5. Contribution to the Evaluation of the Circumferentially-Cracked Round Bar for Fracture Toughness Determination of Reactor Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Scibetta, M

    1999-06-01

    The subject of this PhD dissertation is the use of the Circumferentially-Cracked Round Bar (CRB) for fracture toughness measurements. The main advantages of CRB are the relatively small size requirements of the testing specimens, the low cost to machine the specimen, the rotating bending fatigue allowing for easy precracking of specimens, the use of standard tensile test fixture and the axisymmetry of the specimen that avoids time consuming 3D finite element calculations. An in-depth study of the most widely used precracking technique for CRB, namely the rotating bending fatigue, is made.

  6. Myocardial Noncompaction Presenting With Myocardial Bridge: A Case Report.

    Science.gov (United States)

    Shen, Yuechun; Li, Xinchun; Lu, Dongfeng; Xiao, Aiyi; Li, Jun

    2015-09-01

    Myocardial noncompaction, namly isolated noncompaction of the left ventricular myocardium (NVM), is a rare congenital disease. It can be either seen in the absence of other cardiac anomalies, or associated with other congenital cardiac defects, mostly stenotic lesions of the left ventricular outflow tract. A myocardial bridge (MB) is thought being associated with coronary heart disease, such as coronary spasm, arrhythmia, and so on. The significance of MB in association with other congenital cardiac conditions is unknown.We report a novel case who was presented NVM and MB. A 34-year-old man complained of chest prickling-like pain and dizzy for 1 year. His blood pressure was 110/70 mm Hg. Echocardiograph revealed increased trabeculations below the level of papillary muscle of left ventricle (LV); deep intertrabecular recesses in the endocardial wall of LV particularly in apex free wall; and LV ejection fraction of 57%. A coronary computerized tomography scan showed that part, 38.9 cm, of left descending artery tunnel was surrounding by cardiac muscles rather than resting on top of the myocardium.The therapeutics interventions included lifestyle cares, agents of anti-ischemia and improvement myocardial cell metabolism. The patient was followed up for 2.6 years, and his general condition was stable.This case indicates that NVM can be developed with MB, and the complete diagnosis of NVM and MB should be made by different image studies. PMID:26356695

  7. The Aerodynamic Performance of an Over-the-Rotor Liner With Circumferential Grooves on a High Bypass Ratio Turbofan Rotor

    Science.gov (United States)

    Bozak, Richard F.; Hughes, Christopher E.; Buckley, James

    2013-01-01

    While liners have been utilized throughout turbofan ducts to attenuate fan noise, additional attenuation is obtainable by placing an acoustic liner over-the-rotor. Previous experiments have shown significant fan performance losses when acoustic liners are installed over-the-rotor. The fan blades induce an oscillating flow in the acoustic liners which results in a performance loss near the blade tip. An over-the-rotor liner was designed with circumferential grooves between the fan blade tips and the acoustic liner to reduce the oscillating flow in the acoustic liner. An experiment was conducted in the W-8 Single-Stage Axial Compressor Facility at NASA Glenn Research Center on a 1.5 pressure ratio fan to evaluate the impact of this over-the-rotor treatment design on fan aerodynamic performance. The addition of a circumferentially grooved over-the-rotor design between the fan blades and the acoustic liner reduced the performance loss, in terms of fan adiabatic efficiency, to less than 1 percent which is within the repeatability of this experiment.

  8. Estimation schemes to evaluate elastic-plastic J and COD for throughwall circumferentially cracked elbow under closing moment

    International Nuclear Information System (INIS)

    Leak-before-break (LBB) assessment of primary heat transport piping of nuclear reactors involves detailed fracture assessment of pipes and elbows with postulated throughwall cracks. Fracture assessment requires the calculation of elastic-plastic J-integral and crack opening displacement (COD)1 for these piping components. Analytical estimation schemes to evaluate elastic-plastic J-integral and COD simplify the calculations. These types of estimation schemes are available for pipes with various crack configurations subjected to different types of loading. However, no such schemes are available for throughwall circumferentially cracked elbow (or pipe bend), an important component for LBB analysis. In this paper, simple J and COD estimation schemes are proposed for throughwall circumferentially cracked elbow subjected to closing bending moment. The ovalisation of elbow cross section has a significant bearing on its fracture behavior. Therefore, unlike conventional deformation theory plasticity analysis, incremental flow theory is adopted considering both material and geometric non-linearities in the development of the proposed estimation schemes. Although it violates Ilyushin's theorem, it has been shown that the resulting estimation schemes is still reasonably accurate for engineering purposes. Finally, experimental/numerical validation has been provided by comparing the J-integral and COD between numerical/test data and predictions of the proposed estimation schemes. (authors)

  9. Transpedicular fixation and fusion-arthrodesis circumferential for the treatment of lumbosacral spondylolisthesis of high degree - Multi centric experience

    International Nuclear Information System (INIS)

    The objective is to present the high-grade lumbosacral spondylolisthesis surgical experience. Spondylolisthesis causes chronic disabling pain, postural alteration and/or motor and sensory deficits in the lower extremities. Surgical stabilization is recommended in symptomatic adult and even in children or adolescents without symptoms because of the deformity progression potential. Stabilization can be done with or without reduction of the slippage; reduction implies neurological damage risk, bone (loosening) or implant (rupture) failure. Many authors recommended to do an in situ circumferential fusion arthrosis (inter body and inter transverse) associated with a transpedicular fixation in order to minimize the described risk. Eight patients were operated from 1993 to 2002. spondylolisthesis was analyzed according to clinical presentation, neurological dysfunction, postural alterations (slip angle, sacral inclination) complications and follow up. During follow up solid fusion was obtained with a better neurological function in all cases. One patient presented with a drop foot that reverted posteriorly; other patient had a superficial infection of the wound that was controlled. Slip angle improved between 8 - 42 and sacral inclination to 20 degrades. Present technique is recommended because it can be done a circumferential in situ arthrodesis in a single stage operation

  10. Refinement and evaluation of crack-opening-area analyses for circumferential through-wall cracks in pipes

    International Nuclear Information System (INIS)

    Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet impingement shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. These leak rates depend on the crack-opening area of a through-wall crack in the pipe. In addition to LBB analyses, which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section 11. This study was requested by the NRC to review, evaluate, and refine current analytical models for crack-opening-area analyses of pipes with circumferential through-wall cracks. Twenty-five pipe experiments were analyzed to determine the accuracy of the predictive models. Several practical aspects of crack-opening such as; crack-face pressure, off-center cracks, restraint of pressure-induced bending, cracks in thickness transition regions, weld residual stresses, crack-morphology models, and thermal-hydraulic analysis, were also investigated. 140 refs., 105 figs., 41 tabs

  11. Assessment of myocardial viability using PET

    International Nuclear Information System (INIS)

    The potential for recovery of left ventricular dysfunction after myocardial revascularization represents a practical clinical definition for myocardial viability. The evaluation of viable myocardium in patients with severe global left ventricular dysfunction due to coronary artery disease and with regional dysfunction after acute myocardial infarction is an important issue whether left ventricular dysfunction may be reversible or irreversible after therapy. If the dysfunction is due to stunning or hibernation, functional improvement is observed. But stunned myocardium may recover of dysfunction with no revascularization. Hibernation is chronic process due to chronic reduction in the resting myocardial blood flow. There are two types of myocardial hibernation; 'functional hibernation' with preserved contractile reserve and 'structural hibernation' without contractile reserve in segments with preserved glucose metabolism. This review focus on the application of F-18 FDG and other radionuclides to evaluate myocardial viability. In addition the factors influencing predictive value of FDG imaging for evaluating viability and the different criteria for viability are also reviewed

  12. Reperfusion injury, stunning and myocardial viability

    International Nuclear Information System (INIS)

    Recent experimental data suggest that current thrombolytic strategies may not yet have achieved their full potential for myocardial salvage. In fact, reperfusion may result in microvascular and myocardial cellular injuries. These may translate into transient loss of contractile function ('myocardial stunning'), and possibly contribute to the ultimate extent of myocardial necrosis. The authors review current understanding about the significance, mechanisms, detection and possible treatment of phenomena following reperfusion. A number of imaging modalities, now available to detect the presence and amount of these dysfunctional but variable myocardial segments are presented. These include: Single Photon Emission Computed Tomography, Positron Emission Tomography and Dobutamine Stress Echocardiography. Myocardial reperfusion experiments using animal models have studied possible mechanisms responsible for reperfusion injury. These may help in the search for novel pharmacological and other adjunctive approaches which may-overcome potential adverse effects of reperfusion. 15 refs

  13. Depressive Symptoms Are Associated with Mental Stress-Induced Myocardial Ischemia after Acute Myocardial Infarction

    OpenAIRE

    Jingkai Wei; Pratik Pimple; Shah, Amit J.; Cherie Rooks; Douglas Bremner, J.; Nye, Jonathon A.; Ijeoma Ibeanu; Nancy Murrah; Lucy Shallenberger; Paolo Raggi; Viola Vaccarino

    2014-01-01

    Objectives Depression is an adverse prognostic factor after an acute myocardial infarction (MI), and an increased propensity toward emotionally-driven myocardial ischemia may play a role. We aimed to examine the association between depressive symptoms and mental stress-induced myocardial ischemia in young survivors of an MI. Methods We studied 98 patients (49 women and 49 men) age 38–60 years who were hospitalized for acute MI in the previous 6 months. Patients underwent myocardial perfusion ...

  14. Anterior Myocardial Infarction Associated with Myocardial Bridging in a Young Man

    OpenAIRE

    Ngow, HA; Wan Khairina, WMN

    2010-01-01

    A 43-year-old man presented with acute extensive anterior ST-segment elevation myocardial infarction. During coronary angiogram, a segment of myocardial bridging was noted in the mid-segment of left anteriordescending artery. The association of myocardial bridging and an anterior ST segment elevation is rarely reported in the medical literature. Myocardial bridging is caused by systolic compression of a coronary artery by overlying myocardium tissue. It is a rare coronary artery anomaly, whic...

  15. Kounis Syndrome together with Myocardial Bridging Leading to Acute Myocardial Infarction at Young Age

    OpenAIRE

    Osman Karakaya; Murat Ugurlucan; Fatma Nihan Turhan Caglar; Ilker Murat Caglar; Alper Vural

    2011-01-01

    Kounis syndrome, also named as “allergic angina syndrome,” is a diagnosis in which exposure to an allergen causes mostly coronary spasm and rarely plaque rupture, resulting in ischemic myocardial events. Myocardial bridging is defined as an intramural segment of a coronary artery and its systolic compression by overlying fibers. Myocardial bridging generally has a benign prognosis and mostly affects the mid portion of left anterior descending coronary artery. However, some cases with myocardi...

  16. SERUM MAGNESIUM IN ACUTE MYOCARDIAL INFARCTION

    OpenAIRE

    Nambakam Tanuja; Girish P

    2015-01-01

    BACKGROUND: In myocardial infarction, there occurs functional deficit of available magnesium due to trapping of free magnesium in adipocytes. Magnesium has been implicated in the pathogenesis of acute myocardial infarction and its complications. Magnesium ions are considered essential for the maintenance of functional integrity of myocardium. The serum magnesium concentration was found to have g reat significance in acute myocardial infarction. The present study was un...

  17. Leukocytosis: a risk factor for myocardial infarction

    OpenAIRE

    Kotla SK

    2012-01-01

    Suman K KotlaDepartment of Internal Medicine, Memorial Medical Center, Johnstown, PA, USAAbstract: Myocardial infarction commonly results from atherosclerotic lesions in the coronary arteries. Approximately 5% of patients with acute myocardial infarction do not have atherosclerotic disease. In this case report, we present an unusual leukostatic complication in a patient with acute myeloblastic leukemia and extreme hyperleukocytosis who presented with an acute myocardial infarction that resolv...

  18. Acute myocardial involvement after heroin inhalation

    OpenAIRE

    Ritu Karoli; Fatima, J.; Pushker Singh; Kazmi, Khursheed I.

    2012-01-01

    Amongst the illicit drugs cocaine, amphetamines and cannabis have been studied and documented well to cause myocardial infarction by different mechanisms but there is very sparse data available on myocardial involvement after heroin abuse. We report a young man who developed acute myocardial injury after heroin inhalation and alcohol binge drinking. Heroin induced cardio toxic effect and vasospasm compounded by alcohol were suspected to be the cause of this.

  19. Clinical Practice Guidelines for Acute Myocardial Infarction.

    OpenAIRE

    Francisco de Jesús Valladares Carvajal; Arelys Falcón Hernández; Félix Rolando Jorrín Román; Juan Emilio García Rivas

    2009-01-01

    Clinical Practice Guidelines for Acute Myocardial Infarction. It has been defined as the clinical condition caused by the ischemic myocardial necrosis, usually caused by abrupt reduction of coronary blood irrigation affecting one or more myocardial areas. The document includes a review and update of the concept, classification, diagnosis and therapy. Risk stratification and main aspects of rehabilitation are also stressed. It includes assessment guidelines focused on the most important aspect...

  20. Acute myocardial involvement after heroin inhalation

    Directory of Open Access Journals (Sweden)

    Ritu Karoli

    2012-01-01

    Full Text Available Amongst the illicit drugs cocaine, amphetamines and cannabis have been studied and documented well to cause myocardial infarction by different mechanisms but there is very sparse data available on myocardial involvement after heroin abuse. We report a young man who developed acute myocardial injury after heroin inhalation and alcohol binge drinking. Heroin induced cardio toxic effect and vasospasm compounded by alcohol were suspected to be the cause of this.

  1. Myocardial tissue tagging with cardiovascular magnetic resonance

    OpenAIRE

    Bluemke David A; Osman Nael F; Cheng Susan; Shehata Monda L; Lima João AC

    2009-01-01

    Abstract Cardiovascular magnetic resonance (CMR) is currently the gold standard for assessing both global and regional myocardial function. New tools for quantifying regional function have been recently developed to characterize early myocardial dysfunction in order to improve the identification and management of individuals at risk for heart failure. Of particular interest is CMR myocardial tagging, a non-invasive technique for assessing regional function that provides a detailed and compreh...

  2. Clinical Practice Guidelines for Acute Myocardial Infarction.

    Directory of Open Access Journals (Sweden)

    Francisco De Jesús Valladares Carvajal

    2009-03-01

    Full Text Available Clinical Practice Guidelines for Acute Myocardial Infarction. It has been defined as the clinical condition caused by the ischemic myocardial necrosis, usually caused by abrupt reduction of coronary blood irrigation affecting one or more myocardial areas. The document includes a review and update of the concept, classification, diagnosis and therapy. Risk stratification and main aspects of rehabilitation are also stressed. It includes assessment guidelines focused on the most important aspects to be accomplished.

  3. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    OpenAIRE

    Sujatha M; V Subhadra Devi; C. S. S. Raju; B. Yugandhar; Nagaraju

    2015-01-01

    Introduction: The segment of epicardial coronary artery that traverses intramurally through the myocardium and bridged by a bunch of cardiac muscle fibers is called tunneled artery or intramural artery. The band of cardiac muscle fibers passing over the tunneled artery segment is named as myocardial bridge. During angiography milking effect is observed during systole due to the external pressure of muscle fibers on the tunneled artery that leads to narrowing of vessel lumen and further isc...

  4. Myocardial infarction and subsequent pregnancy

    Directory of Open Access Journals (Sweden)

    Tedoldi Citânia Lúcia

    2000-01-01

    Full Text Available We report the case of a 40-year-old woman with 2 previous myocardial infarctions, revascularization surgery, and an ongoing pregnancy complicated with preeclampsia and fetal hypoxia. Her follow-up performed by a multidisciplinary team made possible the birth through cesarean section of a premature infant of the female sex with a very low birth weight, but without severe respiratory distress of the hyaline membrane disease type. Three months after the delivery, mother and daughter were healthy.

  5. Enteroviruses in Acute Myocardial Infarction

    OpenAIRE

    A Gholoobi; MS Nabavinia; T Mohamadpoor; MS Alavi; Z Meshkat

    2012-01-01

    Background: Human enteroviruses (EVs) may have a role as a possible risk factor in the pathogenesis of MI. The aim of this study was to evaluate the presence of enterovirus genomic RNA in peripheral blood samples of patients with acute myocardial infarction (MI). Methods: We investigated the presence of enterovirus genomic RNA in the peripheral blood of 115 patients with acute MI hospitalized in the Coronary Care Unit of Imam Reza and Ghaem University Hospitals (Mashhad, Iran) by RT-PCR using...

  6. Ventricular Stimulation After Myocardial Infarction

    OpenAIRE

    Béatrice Brembilla-Perrot

    2011-01-01

    Ventricular stimulation after myocardial infarction (MI) is still recommended (class IB) in patients with syncope and left ventricular ejection fraction (LVEF) more than 30-35%, in asymptomatic patients with a LVEF between 30-40% and with non sustained ventricular tachycardia (VT) patients at Holter monitoring. It can also identify patients at high risk of arrhythmic events in the early post-MI period. Combined with imaging methods PVS could be widely used again during VT ablation.

  7. The Orchestra of Myocardial Regeneration

    OpenAIRE

    Siddiqi, S

    2014-01-01

    A glimpse on previous and current literature ignites the recognition of the luxurious era that cardiac science has reached. In particular, the past fifteen years have provided tremendous advancements in the field of myocardial biology with the characterization of cardiac stem cells, reprogramming of somatic cells, microRNA discovery, exosome-protocols and imaging modalities. In addition, conventional and outdated biological processes such as myocyte metabolism, cell cycle, and senescence are ...

  8. Myocardial bridging as a cause of acute myocardial infarction: a case report

    Directory of Open Access Journals (Sweden)

    Emiroglu Yunus

    2002-09-01

    Full Text Available Abstract Background Systolic compression of a coronary artery by overlying myocardial tissue is termed myocardial bridging. Myocardial bridging usually has a benign prognosis, but some cases resulting in myocardial ischemia, infarction and sudden cardiac death have been reported. We are reporting a case of myocardial bridging which was complicated with acute myocardial infarction associated with inappropriate blood donation. Case presentation A 33 year-old-man was admitted to our emergency with acute anteroseptal myocardial infarction after a blood donation. The electrocardiography showed sinus rhythm and was consistent with an acute anteroseptal myocardial infarction. We decided to perform primary percutanous intervention (PCI. Myocardial bridging was observed in the mid segment of the left anterior descending coronary artery on coronary angiogram. PCI was canceled and medical follow up was decided. Blood transfusion was made because he had a deep anemia. A normal hemaglobin level and clinical reperfusion was achieved after ten hours by blood transfusion. At the one year follow up visit, our patient was healthy and had no cardiac complaints. Conclusions Myocardial bridging may cause acute myocardial infarction in various clinical conditions. Although the condition in this case caused profound anemia related acute myocardial infarction, its treatment and management was unusual.

  9. Cardiac MRI for myocardial ischemia.

    LENUS (Irish Health Repository)

    Daly, Caroline

    2013-01-01

    Proper assessment of the physiologic impact of coronary artery stenosis on the LV myocardium can affect patient prognosis and treatment decisions. Cardiac magnetic resonance imaging (CMR) assesses myocardial perfusion by imaging the myocardium during a first-pass transit of an intravenous gadolinium bolus, with spatial and temporal resolution substantially higher than nuclear myocardial perfusion imaging. Coupled with late gadolinium enhancement (LGE) imaging for infarction during the same imaging session, CMR with vasodilating stress perfusion imaging can qualitatively and quantitatively assess the myocardial extent of hypoperfusion from coronary stenosis independent of infarcted myocardium. This approach has been validated experimentally, and multiple clinical trials have established its diagnostic robustness when compared to stress single-photon emission computed tomography. In specialized centers, dobutamine stress CMR has been shown to have incremental diagnostic value above stress echocardiography due to its high imaging quality and ability to image the heart with no restriction of imaging window. This paper reviews the technical aspects, diagnostic utility, prognostic values, challenges to clinical adaptation, and future developments of stress CMR imaging.

  10. Myocardial ischaemia during tracheal intubation and extubation.

    Science.gov (United States)

    Edwards, N D; Alford, A M; Dobson, P M; Peacock, J E; Reilly, C S

    1994-10-01

    The incidence of myocardial ischaemia during tracheal intubation and extubation was compared using ambulatory ECG monitoring in 60 patients undergoing a variety of different surgical operations. Seven patients had myocardial ischaemia after tracheal intubation and seven patients during tracheal extubation. The patients who developed myocardial ischaemia during tracheal extubation had significantly greater rate-pressure products immediately before tracheal extubation (P < 0.05) and 1 min after tracheal extubation (P < 0.01) compared with those patients who did not develop myocardial ischaemia during extubation. PMID:7999498

  11. MYOCARDIAL DEFORMATION AND COMPLETE LEFT BUNDLE BRANCH BLOCK

    Directory of Open Access Journals (Sweden)

    E. N. Pavlyukova

    2015-12-01

    Full Text Available Tissue Doppler imaging is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular systolic and diastolic function. Over the last 10 years, myocardial deformation imaging has become possible initially with tissue Doppler , and more recently with myocardial speckle-tracking using 2D echocardiography. Unlike simple tissue velocity measurements, deformation measurements are specific for the region of interest. Strain rate or strain measurements have been used as sensitive indicators for subclinical diseases, and it is the most widely used tool to assess mechanical dyssynchrony. Left bundle branch block is a frequent, etiologically heterogeneous, clinically hostile and diagnostically challenging entity. About 2% of patients underwent cardiac stress testing show stable or intermittent left bundle branch block. Presence of left bundle branch block is associated with a lower and slower diastolic coronary flow velocity especially during hyperemia. Stress echocardiography is the best option for the diagnosis of ischemic heart disease, albeit specificity and sensitivity reduce in patients with left bundle branch block in the territory of left anterior descending artery in presence of initial septum dyskinesia.

  12. Systemic Atherosclerotic Inflammation Following Acute Myocardial Infarction: Myocardial Infarction Begets Myocardial Infarction

    OpenAIRE

    Joshi, Nikhil V; Toor, Iqbal; Shah, Anoop S V; Carruthers, Kathryn; Alex T. Vesey; Alam, Shirjel R; Sills, Andrew; Hoo, Teng Y; Melville, Adam J; Langlands, Sarah P; Jenkins, William S A; Uren, Neal G; Mills, Nicholas L.; Fletcher, Alison M; van Beek, Edwin J.R.

    2015-01-01

    BACKGROUND: Preclinical data suggest that an acute inflammatory response following myocardial infarction (MI) accelerates systemic atherosclerosis. Using combined positron emission and computed tomography, we investigated whether this phenomenon occurs in humans.METHODS AND RESULTS: Overall, 40 patients with MI and 40 with stable angina underwent thoracic 18F-fluorodeoxyglucose combined positron emission and computed tomography scan. Radiotracer uptake was measured in aortic atheroma and nonv...

  13. Screening for silent myocardial ischemia caseof diabetics : interest of myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Silent myocardial ischemia is a major cause of morbidity and mortality in diabetic patients. Its diagnosis by noninvasive means such as myocardial SPECT would improve the management of these patients. The purpose of this study is to assess the frequency of silent myocardial ischemia in asymptomatic diabetics and their evolution. As a result, the myocardial SPECT is a reliable tool for screening for silent myocardial ischemia in diabetic patients. Its prognostic value allows to stratify the cardiac risk and guide therapeutic management. Its integration into a screening strategy in Tunisia seems limited by its low availability and cost. The latter could be reduced by better patient selection.

  14. Thrombolysis significantly reduces transient myocardial ischaemia following first acute myocardial infarction

    DEFF Research Database (Denmark)

    Mickley, H; Pless, P; Nielsen, J R;

    1992-01-01

    In order to investigate whether thrombolysis affects residual myocardial ischaemia, we prospectively performed a predischarge maximal exercise test and early out-of-hospital ambulatory ST segment monitoring in 123 consecutive men surviving a first acute myocardial infarction (AMI). Seventy...... less than 0.02). Thrombolysis resulted in a non-significant reduction in exercise-induced ST segment depression: prevalence 43% vs 62% in controls. However, during ambulatory monitoring the duration of transient myocardial ischaemia was significantly reduced in thrombolysed patients: 322 min vs 1144...... myocardial ischaemia. This may explain the improvement in myocardial function during physical activities, which was also observed in this study....

  15. Comparison of dobutamine stress echocardiography with exercise reinjection thallium myocardial perfusion scan to detect myocardial cell viability

    International Nuclear Information System (INIS)

    A comparison of dobutamine stress echocardiography with exercise reinjection thallium myocardial perfusion scan on known coronary artery disease patients for detection of myocardial cell viability is given

  16. Advanced echocardiography in adult zebrafish reveals delayed recovery of heart function after myocardial cryoinjury.

    Directory of Open Access Journals (Sweden)

    Selina J Hein

    Full Text Available Translucent zebrafish larvae represent an established model to analyze genetics of cardiac development and human cardiac disease. More recently adult zebrafish are utilized to evaluate mechanisms of cardiac regeneration and by benefiting from recent genome editing technologies, including TALEN and CRISPR, adult zebrafish are emerging as a valuable in vivo model to evaluate novel disease genes and specifically validate disease causing mutations and their underlying pathomechanisms. However, methods to sensitively and non-invasively assess cardiac morphology and performance in adult zebrafish are still limited. We here present a standardized examination protocol to broadly assess cardiac performance in adult zebrafish by advancing conventional echocardiography with modern speckle-tracking analyses. This allows accurate detection of changes in cardiac performance and further enables highly sensitive assessment of regional myocardial motion and deformation in high spatio-temporal resolution. Combining conventional echocardiography measurements with radial and longitudinal velocity, displacement, strain, strain rate and myocardial wall delay rates after myocardial cryoinjury permitted to non-invasively determine injury dimensions and to longitudinally follow functional recovery during cardiac regeneration. We show that functional recovery of cryoinjured hearts occurs in three distinct phases. Importantly, the regeneration process after cryoinjury extends far beyond the proposed 45 days described for ventricular resection with reconstitution of myocardial performance up to 180 days post-injury (dpi. The imaging modalities evaluated here allow sensitive cardiac phenotyping and contribute to further establish adult zebrafish as valuable cardiac disease model beyond the larval developmental stage.

  17. Advanced Echocardiography in Adult Zebrafish Reveals Delayed Recovery of Heart Function after Myocardial Cryoinjury

    Science.gov (United States)

    Kossack, Mandy; Juergensen, Lonny; Fuchs, Dieter; Katus, Hugo A.; Hassel, David

    2015-01-01

    Translucent zebrafish larvae represent an established model to analyze genetics of cardiac development and human cardiac disease. More recently adult zebrafish are utilized to evaluate mechanisms of cardiac regeneration and by benefiting from recent genome editing technologies, including TALEN and CRISPR, adult zebrafish are emerging as a valuable in vivo model to evaluate novel disease genes and specifically validate disease causing mutations and their underlying pathomechanisms. However, methods to sensitively and non-invasively assess cardiac morphology and performance in adult zebrafish are still limited. We here present a standardized examination protocol to broadly assess cardiac performance in adult zebrafish by advancing conventional echocardiography with modern speckle-tracking analyses. This allows accurate detection of changes in cardiac performance and further enables highly sensitive assessment of regional myocardial motion and deformation in high spatio-temporal resolution. Combining conventional echocardiography measurements with radial and longitudinal velocity, displacement, strain, strain rate and myocardial wall delay rates after myocardial cryoinjury permitted to non-invasively determine injury dimensions and to longitudinally follow functional recovery during cardiac regeneration. We show that functional recovery of cryoinjured hearts occurs in three distinct phases. Importantly, the regeneration process after cryoinjury extends far beyond the proposed 45 days described for ventricular resection with reconstitution of myocardial performance up to 180 days post-injury (dpi). The imaging modalities evaluated here allow sensitive cardiac phenotyping and contribute to further establish adult zebrafish as valuable cardiac disease model beyond the larval developmental stage. PMID:25853735

  18. Do episodes of anger trigger myocardial infarction?

    DEFF Research Database (Denmark)

    Möller, J; Hallqvist, J; Diderichsen, Finn;

    1999-01-01

    Our objectives were to study anger as a trigger of acute myocardial infarction (MI) and to explore potential effect modification by usual behavioral patterns related to hostility.......Our objectives were to study anger as a trigger of acute myocardial infarction (MI) and to explore potential effect modification by usual behavioral patterns related to hostility....

  19. Numerical simulation and experimental investigation of temperature distribution in the circumferentially butt GTAW of Incoloy 800H pipes

    International Nuclear Information System (INIS)

    The multi-pass circumferential butt GTAW process of Incoloy 800H pipes was modelled with the FEM in 3D. The element birth and death technique was used for the addition of filler material. Goldak model was used to simulate the distribution of arc heat source. The validation of the simulation model was carried out based on the precise temperature measurements within the HAZ of the welds by thermocouples as well as metallographic characterisation of the cross section of the welds. A good agreement was found between the simulation and experimental results for both thermal field and weld zone shape. The present model showed that increasing the heat input resulted in a wider weld zone as well as a higher HAZ peak temperature. These effects were related to the net heat input and not to either welding current or welding speed, individually. The developed simulation model is a useful tool to investigate the welding thermal regime and the weld pool profile.

  20. Estimates of Partial Safety Factors of Circumferential Through-Wall Cracked Pipes Based on Elastic-Plastic Crack Initiation Criterion

    International Nuclear Information System (INIS)

    Efforts are presently underway for developing an optimal design methodology for GEN-IV nuclear reactors based on target failure probabilities. A typical example is the system-based code, in which the results are represented in the form of partial safety factors (PSFs). Thus, a PSF is one of the crucial elements in either component design or integrity assessment based on target failure probabilities during the operation period. In the present study, a procedure for calculating the PSF of a circumferential through-wall cracked pipe based on the elastic-plastic crack initiation criterion is established, in which the importance of each input variable is assessed. Elastic-plastic J-integrals are calculated using the GE/EPRI and reference stress methods, and the PSF values are calculated using both first- and second-order reliability methods. Moreover, the effect of statistical distributions of assessment variables on the PSF is also evaluated

  1. Transverse shear effects on the stress-intensity factor for a circumferentially cracked, specially orthotropic cylindrical shell

    Science.gov (United States)

    Delale, F.; Erdogan, F.

    1977-01-01

    The problem of a cylindrical shell containing a circumferential through crack is considered by taking into account the effect of transverse shear deformations. The formulation is given for a specially orthotropic material within the confines of a linearized shallow shell theory. The particular theory used permits the consideration of all five boundary conditions regarding moment and stress resultants on the crack surface. Consequently, aside from multiplicative constants representing the stress intensity factors, the membrane and bending components of the asymptotic stress fields near the crack tip are found to be identical. The stress intensity factors are calculated separately for a cylinder under a uniform membrane load, and that under a uniform bending moment. Sample results showing the nature of the out-of-plane crack surface displacement and the effect of the Poisson's ratio are presented.

  2. Ductile fracture behavior of 3-inch diameter carbon steel piping with a circumferential through-wall crack under bending load

    International Nuclear Information System (INIS)

    In order to introduce Leak-Before-Break (LBB) concept into the piping design criteria of the LWR pressure boundary pipings, it is necessary to investigate the pipe fracture behaviors, such as fracture condition and crack opening area, etc. At JAERI, pipe fracture tests of stainless steel and STS42 carbon steel pipes under bending load have been conducted as a part of the LBB research program. This report summarizes the four-point bending test results of 3-inch diameter STS42 carbon steel pipe with a circumferential through-wall crack. Tests were carried out at room temperature. In the tests, the fracture behavior of pipes was investigated to evolute the validity of Net-section collapse criterion, J-R curve and crack opening area. It is shown that the Net-section collapse criterion gives a conservative evaluation for the fracture load of 3-inch diameter carbon steel pipes. (author)

  3. Estimations of C'' and COD for Non-Idealized Circumferential Through-Wall Crack in Cylinders under Creep Conditions

    International Nuclear Information System (INIS)

    On actual crack growth behavior of cylinders, internal surface crack develops through the wall thickness and may partially penetrate the wall thickness at its deepest point. So, the through-wall crack is formed with different crack lengths on inner and outer surface of cylinders during penetration process. These transition cracks are typically referred to as non-idealized through-wall crack (TWC). Therefore, to assess crack growth or leak rate more accurately, estimation of fracture mechanics parameter for non-idealized TWC in cylinders is necessary. In this context, some numerical works have been conducted to derive elastic and plastic fracture mechanics parameters such as stress intensity factor, J-integral and COD under elastic or plastic material behavior. In this study, estimations of C'' and COD for non-idealized circumferential TWC in cylinders under creep condition were addressed through elastic-creep finite element(FE) analyses

  4. Patterns of muscular strain in the embryonic heart wall

    Czech Academy of Sciences Publication Activity Database

    Damon, B. J.; Rémond, M.C.; Bigelow, M.R.; Trusk, T. C.; Xie, W.; Perucchio, R.; Sedmera, David; Denslow, S.; Thompson, R. P.

    2009-01-01

    Roč. 238, č. 6 (2009), s. 1535-1546. ISSN 1058-8388 R&D Projects: GA ČR GA304/08/0615 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z50450515 Keywords : chick embryo * heart development * myocardial strain Subject RIV: EA - Cell Biology Impact factor: 2.833, year: 2009

  5. CFD Study of the Hydrocarbon Boost Low-Pressure Inducer and Kicker in the Presence of a Circumferential Groove

    Science.gov (United States)

    Coker, Robert

    2011-01-01

    Results are presented of a computational fluid dynamics (CFD) study done in support of Marshall Space Flight Center's (MSFC) sub-scale water flow experiments of the Hydrocarbon Boost (HCB) Oxidizer Turbopump (OTP) being developed by the Air Force Research Laboratory (AFRL) and Aerojet. A circumferential groove may be added to the pump to reduce synchronous cavitation and subsequent bearing loads at a minimal performance cost. However, the energy may reappear as high order cavitation (HOC) that spans a relatively large frequency range. Thus, HOC may have implications for the full-scale OTP inducer in terms of reduced structural margin at higher mode frequencies. Simulations using the LOCI/Stream CFD program were conducted in order to explore the fluid dynamical impact of the groove on the low-pressure inducer and kicker. It was found that the circumferential groove has minimal head performance impact, but causes back-flowing high-swirl fluid to interact with the nearly-axial incoming fluid just above the inducer blades. The high-shear interface between the fluids is Kelvin-Helmholtz unstable, resulting in trains of low pressure regions or 'pearls' forming near the upstream edge of the groove. When the static pressure in these regions becomes low enough and they get cut by the blade leading edge, HOC is thought to occur. Although further work is required, the numerical models indicate that HOC will occur in the runbox of the AFRL/Aerojet HCB OTP. Comparisons to the ongoing water flow experiments will be discussed, as well as possible designs that may mitigate HOC while continuing to reduce synchronous cavitation. December 2011 MSS/LPS/SPS Joint Subcommittee Meeting ABSTRACT SUBMITTAL FORM

  6. The stability of growth of a through-wall circumferential crack in a cylindrical pipe subjected to bending deformation

    International Nuclear Information System (INIS)

    Tada, Paris and Gamble have used the tearing modulus approach to examine the stability of growth of a through-wall circumferential crack in a 304 stainless steel circular cylindrical pipe subject to bending deformation. They showed that crack growth is stable, in the sense that growth requires the rotation imposed at the pipe-ends to be increased, provided the pipe length is less than a critical length Lsub(c), which is given by their analysis. The Tada-Paris-Gamble analysis focuses on the question of the stability, or otherwise, of crack growth at the onset of crack extension. The analysis does not consider the possibilities that (a) instability might occur after some stable crack growth, and (b) arrest might occur after some unstable growth. A study of these aspects of the circumferential crack growth problem using the tearing modulus approach is precluded by the geometry dependence of the J-crack growth resistance curve. Consequently the present paper uses a crack tip opening angle criterion to describe crack growth, and thereby demonstrates that possibilities (a) and (b) should both occur, depending on the initial crack length and pipe length. In terms of relevance to the technologically important problem of cracking in Boiling Water Reactor piping, the important conclusion stemming from the paper's analysis is that stability of crack growth after the onset of crack extension is assured if the pipe length is less than a critical length L'sub(c). L'sub(c) is less than Lsub(c), the critical length relevant to the onset of crack extension, but it is still appreciably greater than the pipe run lengths in actual reactor piping systems, and safety against guillotine failure of a pipe is therefore generally assured. (author)

  7. Myocardial infarction and nocturnal hypoxaemia

    Directory of Open Access Journals (Sweden)

    Penčić Biljana

    2007-01-01

    Full Text Available Introduction: There is an increased risk of cardiovascular morbidity and mortality in patients with nocturnal intermittent hypoxaemia. Objecive. The aim of this study was to evalute the influence of nocturnal hypoxaemia on ventricular arrhythmias and myocardial ischaemia in patients with myocardial infarction (MI. Method. We studied 77 patients (55.8±7.9 years with MI free of complications, chronic pulmonary diseases, abnormal awake blood gases tension. All patients underwent overnight pulse oximetry and 24-hour electrocardiography. Patients were divided into two groups according to nocturnal hypoxaemia. Total number of ventricular premature complex (VPC; maximal VPC/h; incidence of VPC Lown class>2 and occurrence of ST-segment depression were analyzed for nocturnal (10 PM to 6 AM, daytime (6 AM to 22 PM periods and for the entire 24 hours. Results. Both groups were similar in age, gender, standard risk factors, myocardial infarction size and did not differ in VPC during the analyzed periods. The number of nocturnal maximal VPC/h was insignificantly greater in group 1 (with hypoxaemia compared to group 2 (without hypoxaemia, (p=0.084. Maximal VPC/h did not differ significantly either for daytime or for 24 hours among the groups. Nocturnal VPC Lown>2 were significantly more frequent in group 1 (25% vs 0%, p=0.002. The incidence of VPC Lown>2 was similar during the daytime, and during 24 hrs in both groups. Occurrence of ST-segment depression did not differ between groups 1 and 2. Conclusion. Nocturnal hypoxaemia was associated with complex nocturnal ventricular arrhythmias in patients with MI. .

  8. [Fibrinolysis in acute myocardial infarct].

    Science.gov (United States)

    Bleifeld, W

    1987-10-24

    Fibrinolysis has opened up a new avenue in the treatment of acute myocardial infarction (AMI). In principle, the rate of reperfusion depends on the type of compound used, the mode of administration and the time between onset of symptoms and the beginning of treatment. With intracoronary streptokinase the reperfusion rate is of the order of 85%. Intravenous urokinase administered as a bolus results in a reopening rate of 50-60%; a similar rate of reperfusion is achieved with rt-PA as infusion, while i.v. streptokinase produces about 50% reopened coronary vessels. The final infarct size is decreased in 70% of patients if fibrinolysis is initiated within 2.5 hours after the onset of symptoms and followed by reopening of the occluded vessel. This results in a lowering of in-hospital mortality, which in various studies is of the order of 45-60%.- Bearing in mind the contraindications, fibrinolysis should be initiated within 3 hours. Hemodynamic improvement by a decrease of infarct size may also be achieved beyond 3 hours in large anterior myocardial infarctions and in posterior infarctions with cardiogenic shock. Early initiation of thrombolysis is of major importance in improving left ventricular function and lowering mortality following acute myocardial infarction. Therefore, prehospital thrombolytic therapy should be considered. - In the postinfarction phase coronary angiography is indicated in patients with angina at rest, stable angina of ECG signs of ischemia. In this situation transfer to a specialized cardiology division for possible percutaneous transluminal angioplasty is indicated. - Reocclusion after successful thrombolysis occurs in 20-30%, and it is therefore important to avoid reinfarction to improve the long term prognosis after AMI.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3321420

  9. Solar activity and myocardial infarction.

    Science.gov (United States)

    Szczeklik, E; Mergentaler, J; Kotlarek-Haus, S; Kuliszkiewicz-Janus, M; Kucharczyk, J; Janus, W

    1983-01-01

    The correlation between the incidence of myocardial infarction, sudden cardiac death, the solar activity and geomagnetism in the period 1969-1976 was studied, basing on Wrocław hospitals material registered according to WHO standards; sudden death was assumed when a person died within 24 hours after the onset of the disease. The highest number of infarctions and sudden deaths was detected for 1975, which coincided with the lowest solar activity, and the lowest one for the years 1969-1970 coinciding with the highest solar activity. Such an inverse, statistically significant correlation was not found to exist between the studied biological phenomena and geomagnetism. PMID:6851574

  10. Psychosocial work environment and myocardial infarction: improving risk estimation by combining two complementary job stress models in the SHEEP Study

    OpenAIRE

    Peter, R.; Siegrist, J; Hallqvist, J; Reuterwall, C; Theorell, T.

    2002-01-01

    Objectives: Associations between two alternative formulations of job stress derived from the effort-reward imbalance and the job strain model and first non-fatal acute myocardial infarction were studied. Whereas the job strain model concentrates on situational (extrinsic) characteristics the effort-reward imbalance model analyses distinct person (intrinsic) characteristics in addition to situational ones. In view of these conceptual differences the hypothesis was tested that combining informa...

  11. Rehabilitation program for prosthetic tracheojejunal voice production and swallowing function following circumferential pharyngolaryngectomy and neopharyngeal reconstruction with a jejunal free flap

    NARCIS (Netherlands)

    L.W.J. Baijens; R. Speijer; N. Roodenburg; F.J.M. Hilgers

    2011-01-01

    The case of a 68-year-old woman with postoperative speech and swallowing problems following a circumferential pharyngolaryngectomy and neopharyngeal reconstruction with a jejunal free flap is presented. The primary tumor was an extended papillary thyroid carcinoma (pT4N0M0). For vocal restoration, a

  12. Circadian influences on myocardial infarction.

    Science.gov (United States)

    Virag, Jitka A I; Lust, Robert M

    2014-01-01

    Components of circadian rhythm maintenance, or "clock genes," are endogenous entrainable oscillations of about 24 h that regulate biological processes and are found in the suprachaismatic nucleus (SCN) and many peripheral tissues, including the heart. They are influenced by external cues, or Zeitgebers, such as light and heat, and can influence such diverse phenomena as cytokine expression immune cells, metabolic activity of cardiac myocytes, and vasodilator regulation by vascular endothelial cells. While it is known that the central master clock in the SCN synchronizes peripheral physiologic rhythms, the mechanisms by which the information is transmitted are complex and may include hormonal, metabolic, and neuronal inputs. Whether circadian patterns are causally related to the observed periodicity of events, or whether they are simply epi-phenomena is not well established, but a few studies suggest that the circadian effects likely are real in their impact on myocardial infarct incidence. Cycle disturbances may be harbingers of predisposition and subsequent response to acute and chronic cardiac injury, and identifying the complex interactions of circadian rhythms and myocardial infarction may provide insights into possible preventative and therapeutic strategies for susceptible populations. PMID:25400588

  13. Contemporaryperspective on endogenous myocardial regeneration

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Considering the complex nature of the adult heart,it is no wonder that innate regenerative processes,while maintaining adequate cardiac function, fall shortin myocardial jeopardy. In spite of these enchaining limitations, cardiac rejuvenation occurs as well asrestricted regeneration. In this review, the backgroundas well as potential mechanisms of endogenousmyocardial regeneration are summarized. We presentand analyze the available evidence in three subsequentsteps. First, we examine the experimental researchdata that provide insights into the mechanisms andorigins of the replicating cardiac myocytes, includingcell populations referred to as cardiac progenitor cells(i.e. , c-kit+ cells). Second, we describe the role ofclinical settings such as acute or chronic myocardialischemia, as initiators of pathways of endogenousmyocardial regeneration. Third, the hitherto conductedclinical studies that examined different approachesof initiating endogenous myocardial regeneration infailing human hearts are analyzed. In conclusion, wepresent the evidence in support of the notion thatregaining cardiac function beyond cellular replacementof dysfunctional myocardium via initiation of innateregenerative pathways could create a new perspectiveand a paradigm change in heart failure therapeutics.Reinitiating cardiac morphogenesis by reintroducingdevelopmental pathways in the adult failing heart mightprovide a feasible way of tissue regeneration. Basedon our hypothesis "embryonic recall", we present firstsupporting evidence on regenerative impulses in themyocardium, as induced by developmental processes.

  14. Comprehensive Cardiovascular magnetic resonance of myocardial mechanics in mice using three-dimensional cine DENSE

    Directory of Open Access Journals (Sweden)

    Zhong Xiaodong

    2011-12-01

    Full Text Available Abstract Background Quantitative noninvasive imaging of myocardial mechanics in mice enables studies of the roles of individual genes in cardiac function. We sought to develop comprehensive three-dimensional methods for imaging myocardial mechanics in mice. Methods A 3D cine DENSE pulse sequence was implemented on a 7T small-bore scanner. The sequence used three-point phase cycling for artifact suppression and a stack-of-spirals k-space trajectory for efficient data acquisition. A semi-automatic 2D method was adapted for 3D image segmentation, and automated 3D methods to calculate strain, twist, and torsion were employed. A scan protocol that covered the majority of the left ventricle in a scan time of less than 25 minutes was developed, and seven healthy C57Bl/6 mice were studied. Results Using these methods, multiphase normal and shear strains were measured, as were myocardial twist and torsion. Peak end-systolic values for the normal strains at the mid-ventricular level were 0.29 ± 0.17, -0.13 ± 0.03, and -0.18 ± 0.14 for Err, Ecc, and Ell, respectively. Peak end-systolic values for the shear strains were 0.00 ± 0.08, 0.04 ± 0.12, and 0.03 ± 0.07 for Erc, Erl, and Ecl, respectively. The peak end-systolic normalized torsion was 5.6 ± 0.9°. Conclusions Using a 3D cine DENSE sequence tailored for cardiac imaging in mice at 7 T, a comprehensive assessment of 3D myocardial mechanics can be achieved with a scan time of less than 25 minutes and an image analysis time of approximately 1 hour.

  15. Regional myocardial function after intracoronary bone marrow cell injection in reperfused anterior wall infarction - a cardiovascular magnetic resonance tagging study

    Directory of Open Access Journals (Sweden)

    Arnesen Harald

    2011-03-01

    Full Text Available Abstract Background Trials have brought diverse results of bone marrow stem cell treatment in necrotic myocardium. This substudy from the Autologous Stem Cell Transplantation in Acute Myocardial Infarction trial (ASTAMI explored global and regional myocardial function after intracoronary injection of autologous mononuclear bone marrow cells (mBMC in acute anterior wall myocardial infarction treated with percutaneous coronary intervention. Methods Cardiovascular magnetic resonance (CMR tagging was performed 2-3 weeks and 6 months after revascularization in 15 patients treated with intracoronary stem cell injection (mBMC group and in 13 controls without sham injection. Global and regional left ventricular (LV strain and LV twist were correlated to cine CMR and late gadolinium enhancement (LGE. Results In the control group myocardial function as measured by strain improved for the global LV (6 months: -13.1 ± 2.4 versus 2-3 weeks: -11.9 ± 3.4%, p = 0.014 and for the infarct zone (-11.8 ± 3.0 versus -9.3 ± 4.1%, p = 0.001, and significantly more than in the mBMC group (inter-group p = 0.027 for global strain, respectively p = 0.009 for infarct zone strain. LV infarct mass decreased (35.7 ± 20.4 versus 45.7 ± 29.5 g, p = 0.024, also significantly more pronounced than the mBMC group (inter-group p = 0.034. LV twist was initially low and remained unchanged irrespective of therapy. Conclusions LGE and strain findings quite similarly demonstrate subtle differences between the mBMC and control groups. Intracoronary injection of autologous mBMC did not strengthen regional or global myocardial function in this substudy. Trial registration ClinicalTrials.gov: NCT00199823

  16. New imaging techniques in myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    Gated myocardial SPECT and attenuation correction gave birth to new insights into the pathophysiology of ischemic myocardial perfusion and function in clinical routine practice. Gated myocardial Tc-99m-compound SPECT improved diagnostic accuracy of coronary artery disease and enabled us to observe motion and thickening of myocardial walls as well as myocardial perfusion at the same time. Quantitative and qualitative assessment of myocardial performance and perfusion let us to understand the myocardial physiology in ischemia and infarction. In every patient who underwent gated perfusion SPECT, we will find ejection fraction, left ventricular volumes and regional wall motion. There are hopes to use gated Tl-201 SPECT for the same purpose and to use gated SPECT for evaluation of wall motion and thickening at stress or immediate post-stress. Attenuation correction could improve diagnostic accuracy mainly by increasing normalcy ratio or performance of non-expert physicians Both gated methods and attenuation correction improved specificity of non-expert physicians in diagnosing patients with moderate pretest likelihood. New imaging techniques will fill the desire of cardiologists to examine function and perfusion, and possibly metabolism in their clinical routine practice

  17. Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction by Biomarkers

    Science.gov (United States)

    2016-01-25

    Acute Myocardial Infarction (AMI); Acute Coronary Syndrome (ACS); ST Elevation (STEMI) Myocardial Infarction; Ischemic Reperfusion Injury; Non-ST Elevation (NSTEMI) Myocardial Infarction; Angina, Unstable

  18. The May 2005 eruption of Fernandina volcano, Galápagos: The first circumferential dike intrusion observed by GPS and InSAR

    Science.gov (United States)

    Chadwick, W.W., Jr.; Jonsson, Sigurjon; Geist, Dennis J.; Poland, M.; Johnson, Daniel J.; Batt, S.; Harpp, Karen S.; Ruiz, A.

    2011-01-01

    The May 2005 eruption of Fernandina volcano, Galápagos, occurred along circumferential fissures parallel to the caldera rim and fed lava flows down the steep southwestern slope of the volcano for several weeks. This was the first circumferential dike intrusion ever observed by both InSAR and GPS measurements and thus provides an opportunity to determine the subsurface geometry of these enigmatic structures that are common on Galápagos volcanoes but are rare elsewhere. Pre- and post- eruption ground deformation between 2002 and 2006 can be modeled by the inflation of two separate magma reservoirs beneath the caldera: a shallow sill at ~1 km depth and a deeper point-source at ~5 km depth, and we infer that this system also existed at the time of the 2005 eruption. The co-eruption deformation is dominated by uplift near the 2005 eruptive fissures, superimposed on a broad subsidence centered on the caldera. Modeling of the co-eruption deformation was performed by including various combinations of planar dislocations to simulate the 2005 circumferential dike intrusion. We found that a single planar dike could not match both the InSAR and GPS data. Our best-fit model includes three planar dikes connected along hinge lines to simulate a curved concave shell that is steeply dipping (~45–60°) toward the caldera at the surface and more gently dipping (~12–14°) at depth where it connects to the horizontal sub-caldera sill. The shallow sill is underlain by the deep point source. The geometry of this modeled magmatic system is consistent with the petrology of Fernandina lavas, which suggest that circumferential eruptions tap the shallowest parts of the system, whereas radial eruptions are fed from deeper levels. The recent history of eruptions at Fernandina is also consistent with the idea that circumferential and radial intrusions are sometimes in a stress-feedback relationship and alternate in time with one another.

  19. Myocardial structural alteration and systolic dysfunction in preclinical hypertrophic cardiomyopathy mutation carriers.

    Directory of Open Access Journals (Sweden)

    Kai Hang Yiu

    Full Text Available BACKGROUND: To evaluate the presence of myocardial structural alterations and subtle myocardial dysfunction during familial screening in asymptomatic mutation carriers without hypertrophic cardiomyopathy (HCM phenotype. METHODS AND FINDINGS: Sixteen HCM families with pathogenic mutation were studied and 46 patients with phenotype expression (Mut+/Phen+ and 47 patients without phenotype expression (Mut+/Phen- were observed. Twenty-five control subjects, matched with the Mut+/Phen- group, were recruited for comparison. Echocardiography was performed to evaluate conventional parameters, myocardial structural alteration by calibrated integrated backscatter (cIBS and global and segmental longitudinal strain by speckle tracking analysis. All 3 groups had similar left ventricular dimensions and ejection fraction. Basal anteroseptal cIBS was the highest in Mut+/Phen+ patients (-14.0±4.6 dB, p-19.0 dB basal anteroseptal cIBS or >-18.0% basal anteroseptal longitudinal strain had a sensitivity of 98% and a specificity of 72% in differentiating Mut+/Phen- group from controls. CONCLUSION: The use of cIBS and segmental longitudinal strain can differentiate HCM Mut+/Phen- patients from controls with important clinical implications for the family screening and follow-up of these patients.

  20. Clinical Characteristics and Outcomes of Patients with Myocardial Infarction, Myocardial Injury, and Nonelevated Troponins

    DEFF Research Database (Denmark)

    Sarkisian, Laura; Saaby, Lotte; Poulsen, Tina S; Gerke, Oke; Jangaard, Nikolaj; Hosbond, Susanne; Diederichsen, Axel C P; Thygesen, Kristian; Mickley, Hans

    2016-01-01

    troponin value is encountered in the absence of obvious myocardial ischemia, a careful search for other clinical conditions is crucial. METHODS: In 2010 to 2011, we prospectively studied hospitalized patients who had cardiac troponin I measured on clinical indication. An acute myocardial infarction was...... values ≤30 ng/L were classified as nonelevated cardiac troponin I. Follow-up was at least 3 years with all-cause mortality as the sole clinical end point. RESULTS: A total of 3762 patients were included. Of these, 488 (13%) had acute myocardial infarction, 1089 (29%) had myocardial injury, and 2185 (58......%, respectively). CONCLUSIONS: Patients with myocardial injury are older and have more comorbidity than those with acute myocardial infarction. Both groups exhibit a poorer prognosis than patients with nonelevated cardiac troponin I values. Of note, a very high long-term mortality is observed in patients with...

  1. Myocardial Structural and Biological Anomalies Induced by High Fat Diet in Psammomys obesus Gerbils.

    Directory of Open Access Journals (Sweden)

    Abdelhamid Sahraoui

    Full Text Available Psammomys obesus gerbils are particularly prone to develop diabetes and obesity after brief period of abundant food intake. A hypercaloric high fat diet has been shown to affect cardiac function. Here, we sought to determine whether a short period of high fat feeding might alter myocardial structure and expression of calcium handling proteins in this particular strain of gerbils.Twenty Psammomys obesus gerbils were randomly assigned to receive a normal plant diet (controls or a high fat diet. At baseline and 16-week later, body weight, plasma biochemical parameters (including lipid and carbohydrate levels were evaluated. Myocardial samples were collected for pathobiological evaluation.Sixteen-week high fat dieting resulted in body weight gain and hyperlipidemia, while levels of carbohydrates remained unchanged. At myocardial level, high fat diet induced structural disorganization, including cardiomyocyte hypertrophy, lipid accumulation, interstitial and perivascular fibrosis and increased number of infiltrating neutrophils. Myocardial expressions of pro-apoptotic Bax-to-Bcl-2 ratio, pro-inflammatory cytokines [interleukin (IL-1β and tumor necrosis factor (TNF-α], intercellular (ICAM1 and vascular adhesion molecules (VCAM1 increased, while gene encoding cardiac muscle protein, the alpha myosin heavy polypeptide (MYH6, was downregulated. Myocardial expressions of sarco(endoplasmic calcium-ATPase (SERCA2 and voltage-dependent calcium channel (Cacna1c decreased, while protein kinase A (PKA and calcium-calmodulin-dependent protein kinase (CaMK2D expressions increased. Myocardial expressions of ryanodine receptor, phospholamban and sodium/calcium exchanger (Slc8a1 did not change.We conclude that a relative short period of high fat diet in Psammomys obesus results in severe alterations of cardiac structure, activation of inflammatory and apoptotic processes, and altered expression of calcium-cycling determinants.

  2. Nitroglycerine Induced Acute Myocardial Infarction in a Patient with Myocardial Bridging

    OpenAIRE

    Dragana Rujic; Mette Lundgren Nielsen; Karsten Tange Veien; Manan Pareek

    2014-01-01

    Muscle overlying an intramyocardial segment of a coronary artery is termed a myocardial bridge. The intramyocardial segment, the tunneled artery, is compressed during systole. The condition is generally benign but may occasionally cause myocardial ischemia, infarction, arrhythmia, or sudden cardiac death. We present a case regarding a 52-year-old man with exercise-induced angina who was diagnosed with a myocardial bridge overlying the left anterior descending artery. He was initially treated ...

  3. Histochemical and immunohistochemical analyses of the myocardial scar fallowing acute myocardial infarction

    OpenAIRE

    Tatić Vujadin; Rafajlovski Sašo; Kanjuh Vladimir; Gajanin Radoslav; Suščević Dušan; Balint Bela; Obradović Slobodan

    2012-01-01

    Background/Aim. The heart has traditionally been considered as a static organ without capacity of regeneration after trauma. Currently, the more and more often asked question is whether the heart has any intrinsic capacities to regenerate myocytes after myocardial infarction. The aim of this study was to present the existence of the preserved muscle fibers in the myocardial scar following myocardial infarction as well as the presence of numerous cells of various size and form that diffe...

  4. Exercise gated planar myocardial perfusion imaging using technetium-99m sestamibi for the diagnosis of coronary artery disease: an alternative to exercise tomographic imaging

    International Nuclear Information System (INIS)

    This prospective study was designed to evaluate the diagnostic performance of 99mTc-sestamibi exercise gated planar myocardial imaging by comparison with both visual and quantitative analyses of SPET. The study was conducted in 115 consecutive patients with known or suspected CAD, including 54 patients with a previous myocardial infarction (MI), referred for exercise testing prior to coronary angiography. Multi-gated planar imaging and SPET were performed after bicycle exercise. The end-diastolic (ED) and SPET images were visually scored (SVi). Myocardial uptake was quantitated on SPET slices using maximum count circumferential profiles (SQu) and defect extent was measured by comparison with gender-matched data sets obtained from 27 controls (50% and/or regional wall motion abnormality. The cut-off criteria for positivity of the three procedures were determined from receiver operating characteristic (ROC) curves derived from the data of patients without previous MI. The area under the ROC curves was similar for ED, SVi and SQu. This was confirmed by the analysis of sensitivity performed using the ROC curve-derived cut-off criteria, in patients with or without previous MI. SVi was more sensitive than ED in identifying the diseased vessel(s) (ED: 41% vs SVi: 80%); but ED was more specific in this respect (ED: 79% vs SVi: 61%). (orig.)

  5. Effects of incremental beta-blocker dosing on myocardial mechanics of the human left ventricle: MRI 3D-tagging insight into pharmacodynamics supports theory of inner antagonism.

    Science.gov (United States)

    Schmitt, Boris; Li, Tieyan; Kutty, Shelby; Khasheei, Alireza; Schmitt, Katharina R L; Anderson, Robert H; Lunkenheimer, Paul P; Berger, Felix; Kühne, Titus; Peters, Björn

    2015-07-01

    Beta-blockers contribute to treatment of heart failure. Their mechanism of action, however, is incompletely understood. Gradients in beta-blocker sensitivity of helically aligned cardiomyocytes compared with counteracting transversely intruding cardiomyocytes seem crucial. We hypothesize that selective blockade of transversely intruding cardiomyocytes by low-dose beta-blockade unloads ventricular performance. Cardiac magnetic resonance imaging (MRI) 3D tagging delivers parameters of myocardial performance. We studied 13 healthy volunteers by MRI 3D tagging during escalated intravenous administration of esmolol. The circumferential, longitudinal, and radial myocardial shortening was determined for each dose. The curves were analyzed for peak value, time-to-peak, upslope, and area-under-the-curve. At low doses, from 5 to 25 μg·kg(-1)·min(-1), peak contraction increased while time-to-peak decreased yielding a steeper upslope. Combining the values revealed a left shift of the curves at low doses compared with baseline without esmolol. At doses of 50 to 150 μg·kg(-1)·min(-1), a right shift with flattening occurred. In healthy volunteers we found more pronounced myocardial shortening at low compared with clinical dosage of beta-blockers. In patients with ventricular hypertrophy and higher prevalence of transversely intruding cardiomyocytes selective low-dose beta-blockade could be even more effective. MRI 3D tagging could help to determine optimal individual beta-blocker dosing avoiding undesirable side effects. PMID:25888512

  6. SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

    Science.gov (United States)

    Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

    2016-01-01

    Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions. PMID:26053731

  7. Comparative study on the localization of myocardial ischemia by myocardial perfusion SPECT and exercise electrocardiography

    International Nuclear Information System (INIS)

    Objective: To investigate the correspondence between the myocardial perfusion SPECT and exercise electrocardiography (ECG) in localization of myocardial ischemia. Methods: Three hundred and two patients with abnormal findings in the myocardial perfusion SPECT and ECG were selected and Chi-square test was performed to analyze the relationship between ECG and SPECT in determining the ischemic myocardial segment. Results: Compared with patients with ST depression, most patients with ST elevation had significantly more angina symptoms in history occurring during exercise test, and lower exercise tolerability (P<0.05). Some weak correspondence (K=0.36, P<0.01) was shown between the localization of ST depression and defect territory of myocardial perfusion, while a complete correspondence (K=1.00, P<0.01) between ST elevation and SPECT in determining the abnormal myocardial segment was observed. In patients with anterior ST depression, perfusion defects occurred more frequently in left anterior descending coronary artery (LAD) territory (66.9%) than in right coronary artery (RCA) territory (33.1%). ST segment depression related poorly with the results of myocardial perfusion in determining the defects. Conclusion: The exercise-induced ST elevation is more correspondent to the defects of myocardial perfusion in the localization of myocardial ischemia compared with ST depression

  8. The clinical application value of myocardial perfusion imaging in evaluating coronary artery myocardial bridge patients with symptoms

    International Nuclear Information System (INIS)

    Objective: Myocardial bridge is a common inborn coronary artery anomaly, myocardial bridge may be associated with myocardial ischemia. Only a few patients with coronary artery myocardial bridge were evaluated with nuclear medicine techniques. The aim of this study was to investigate the role of nuclear cardiology with myocardial perfusion technique in symptomatic myocardial bridge patients. Methods Nineteen myocardial bridge patients with the symptoms of chest pain and chest distress were analyzed retrospectively. 99Tcm-methoxyisobutylisonitrile (MIBI) myocardial perfusion images (both exercise and rest) were performed in all. Imaging results were compared with the results of movement electrocardiogram (ECG) and coronary arteriography. The t test or χ2 test was used to statistically analyze the data with Stata 7.0 software. Results: Of the 19 patients, 18 patients had myocardial bridge locating at the left anterior descending artery, 1 patient at the left anterior descending and left circumflex artery, the mean angiographic systolic occlusion within the myocardial bridge was (65.4 ± 22.1)%. Of these 19 patients, Exercise-rest 99Tcm-MIBI myocardial perfusion imaging defined positive myocardial ischemia in 10 and negative in 9 patients. Of the 10 patients with 99Tcm-MIBI myocardial perfusion imaging defined myocardial ischemia, 8 had reversible radioactive defect of partial anterior wall and (or) apex, 1 had reversible defect of post lateral wall and post septal wall, and 1 had reversible defect of inferior wall. The positive predictive value of myocardial perfusion imaging was 52.6% (10/19), which was higher than movement ECG [21.1% (4/19), χ2= 4.07, P 99Tcm-MIBI myocardial periusion imaging defined myocardial ischemia. Six cases with Grade II stenosis, two were 99Tcm-MIBI myocardial perfusion imaging defined myocardial ischemia. Eight cases with Grade III stenosis, seven were 99Tcm-MIBI myocardial perfusion imaging defined myocardial ischemia. The mean angio

  9. 超声斑点追踪技术评价微泡造影剂介导SERCA2a基因治疗心肌梗死大鼠的实验研究%Ultrasound-mediated destruction of microbubbles directs SERCA2a gene delivery to rats with myocardial infarction by two-dimensional ultrasound speckle tracking imaging

    Institute of Scientific and Technical Information of China (English)

    姜新魁; 穆玉明; 王春梅; 唐琪; 关丽娜

    2010-01-01

    Objective To evaluate the therapeutic effects of rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles in rats with myocardial infarction(MI) using speckle tracking echocardiography (STE). Methods Thirty-five male SD rats were divided into Sham group, MI group and gene therapy group. rAAV2-SERCA2a was attached to the surface of SonoVue, sulphur hexafluoride-filled microbubbles. Therapy group animals were infused with those mixed fluids through tail vein. The other two groups were infused with SonoVue microbubbles. These bubbles were infused with simultaneous echocardiography. Four weeks after ultrasound microbubbles destructed,Circumferential strain rate(SRcir), radial strain rate(SRrad) and left ventricular torsion (LVtor) of regional myocardium were measured in short-axis view using speckle tracking imaging software for each animal. Results Compared with the M1 group,there were significant increase in SRcir-S,SRcir-E, SRrad-S,SRrad-E and LVtor in rats of gene therapy group( P <0. 01 ). There was no significant difference between gene therapy group and sham group. Conclusions rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles could enhance cardiac function of rats with MI.%目的 应用二维超声斑点追踪显像技术评价超声微泡造影剂介导rAAV2-SERCA2a基因靶向治疗心肌梗死大鼠左心室功能的疗效.方法 健康雄性SD大鼠35只,随机分为3组:假手术组、心肌梗死组和基因治疗组.心肌梗死组及基因治疗组结扎冠状动脉左前降支近端,造成前壁心肌梗死.假手术组单纯开胸不结扎冠状动脉.4周时,基因治疗组注射rAAV2-SERCA2a与造影剂混合液,假手术组及心肌梗死组仅注射造影剂,以上各组均给予心肌定点超声辐照.干预4周时,测量各组大鼠左心室短轴观乳头肌水平径向应变率(radial strain rate,SRrad)和圆周应变率(circumferential strain rate,SRcir)的收缩期峰值(SRrad-S

  10. Radiofrequency Ablation Mapping with Circumferential Catheter for Paroxys-mal Atrial Fibrillation Originating From the Pulmonary Veins

    Institute of Scientific and Technical Information of China (English)

    刘震; 吴书林; 杨平珍; 方咸宏; 李海杰; 陈泗林; 詹贤章; 薛玉梅

    2002-01-01

    Objectives To assessed thefeasibility and effectiveness of electrophysiologicalmapping of pulmonary veins with a circumferential 10-electrode catheter and radiofrequency catheter abla-tion therapy for patients with paroxysmal atrial fibril-lation. Background Standard mapping and ablationof focal sources of atrial fibrillation are associated withvery long procedure times and low efficacy. Mappingand ablation pulmonary veins guide with a circularcatheter could overcome these limitations. Methods16 patients [male 11, female 5, mean age (51 +14.5) years] with paroxysmal atrial fibrillation refrac-tory to antiarrhythmic drugs were included in thisgroup. A circumferential 10-electrode catheter wasused to pulmonary vein mapping during sinus rhythm orCSd pacing to determine the origin of atrial prematurecontractions. When the ablative target pulmonary veinwas found, the pulmonary vein potentials' distributionand activation were assessment pulmonary veins' ostialablation was performed at the segments showing earliestactivation of pulnonary vein potentials. The end pointwas designed: 1 ) elimination of pulmonary vein po-tential; 2) pulmonary vein potential dissociation fromatrial waves; 3) atrial ectopic beats disappear. ResultsA total of 36 pulmonary veins were ablated, in-cluding 16 left superior, 12 right superior, 7 left in-ferior and 1 right inferior. 1 pulmonary vein in 2 pa-tients was ablated, 2 pulmonary veins in 8 patientswere ablated, 3 pulmonary veins were ablated in 5patients and 4 pulmonary veins were ablated in 1 pa-tient. Procedure duration and fluoroscopy time respec-tively were 186.7 _+ 63.8 min and 51.5 + 15.0 min.During the follow-up 1- 12 months, 11 patients(68.7 % ) were free of AF without any antiarrhythmicdrugs, 2 of them were reablation, effective in 3/16(18.7%) and unsuccessful in 2/16 (12.6%) . 2cases recurred with atrial premature, 1 was treated withamiodarone and the other was repeat electrophysiologi-cal mapping and ablation, 5 cases with

  11. Experimental myocardial ischemia. Pt. 2

    International Nuclear Information System (INIS)

    The comparative effects of meglumine sodium diatrizoate (MSD), sodium meglumine calcium metrizoate (SMCM), and metrizamide (M) were studied in an isolated canine heart preparation. The parameters observed were coronary blood flow (CBF), myocardial contractile force (MCF), positive and negative dF/dt, and perfusion pressure during normal and ischemic perfusion conditions. MSD had an initial negative inotropic effect but baseline MCF returned in 1 min during normal perfusion and 2 min under ischemic conditions. SMCM and M had only a positive inotropic effect under normal perfusion. However, during ischemia, the positive effect of SMCM was followed by a decrease in contractile force. M showed only a positive effect on force during ischemia. Our results indicate that calcium additive may increase the risk of coronary arteriography in patients with severe coronary artery disease. (orig.)

  12. Myocardial involvement in muscular dystrophy evaluated by thallium-201 emission computed tomography

    International Nuclear Information System (INIS)

    The clinical usefulness of thallium-201 myocardial emission computed tomography (ECT) for evaluating left ventricular myocardial fibrosis was assessed in 47 patients with Duchenne (MD), facio-scapulo-humeral (FSH), limb-girdle (LG) and myotonic (MT) dystrophy. 1. Trans-, long- and short-axial images were interpreted quantitatively by circumferential profile analysis, and the extent of fibrotic tissue (%FIB) was estimated by integrating hypoperfused areas in six to eight consecutive short-axial slices. Lung/mediastinum count ratio (L/M ratio), LV cavity dilatation, aneurysm formation and cardiac malrotation were also assessed with ECT. 2. Distinct ECT defects were demonstrated in 95 of a total of 235 LV segments (40 %) and in 37 of 47 cases (85 % of DMD, 71 % of FSH, 50 % of MT and 60 % of LG). They were observed specifically in the posterior wall (82 %) and the apex (65 %) in DMD, and were scattered in all LV wall segments in FSH, LG, and MT. 3. There was a significant correlation between %FIB and the L/M ratio (r = 0.79, p < 0.001), and the L/M ratio was significantly higher in DMD than in MT (0.67 ± 0.36 vs 0.34 ± 0.25, p < 0.05). 4. ECT showed marked LV dilatation in seven (15 %), apical aneurysm in five (11 %) and vertical heart in 12 (26 %) of the 47 patients. 5. There were no significant correlations between age or clinical stage scores and numbers of defect segments or %FIB in each group. 6. During the one-year follow-up period of these patients, a DMD boy with the largest %FIB (54 %) and the highest L/M ratio (1.4) together with LV dilatation had complications of refractory heart failure and he died eight months following the ECT examination. 7. Thallium-201 planar imaging and standard 12-lead ECG underestimated the perfusion defects which were evaluated with ECT. (author)

  13. Repetitive myocardial infarctions secondary to delirium tremens.

    Science.gov (United States)

    Schwartzberg, David; Shiroff, Adam

    2014-01-01

    Delirium tremens develops in a minority of patients undergoing acute alcohol withdrawal; however, that minority is vulnerable to significant morbidity and mortality. Historically, benzodiazepines are given intravenously to control withdrawal symptoms, although occasionally a more substantial medication is needed to prevent the devastating effects of delirium tremens, that is, propofol. We report a trauma patient who required propofol sedation for delirium tremens that was refractory to benzodiazepine treatment. Extubed prematurely, he suffered a non-ST segment myocardial infarction followed by an ST segment myocardial infarction requiring multiple interventions by cardiology. We hypothesize that his myocardial ischemia was secondary to an increased myocardial oxygen demand that occurred during his stress-induced catecholamine surge during the time he was undertreated for delirium tremens. This advocates for the use of propofol for refractory benzodiazepine treatment of delirium tremens and adds to the literature on the instability patients experience during withdrawal. PMID:25197580

  14. Myocardial hypoperfusion on conventional contrast computed tomography.

    Science.gov (United States)

    Ching, Shing; Chung, Tak Shun

    2015-10-01

    Non–electrocardiogram (ECG)–gated contrast computed tomography (CT) is commonly performed to exclude aortic dissection in chest pain patients. Besides evaluating the aorta for dissection flap, attention should be paid to the myocardium for areas of hypoenhancement that may suggest ischemia. Current models of multidetector CT enable assessment of myocardial perfusion with minimal motion artifact even without ECG gating. Transmural hypoenhancement with preserved wall thickness in a coronary distribution is highly specific for acute myocardial infarction. We report 2 cases of acute chest pain with initial nondiagnostic studies that underwent CT aortogram to exclude dissection. Instead, the CT showed myocardial hypoenhancement in left anterior descending artery territory. Myocardial hypoenhancement occurred before ST-segment elevation on ECG, suggesting that recognition of this important finding may lead to earlier revascularization decisions. PMID:26321167

  15. Differential Local Spasticity in Myocardial Bridges

    OpenAIRE

    Angelini, Paolo; Uribe, Carlo; Lozano, Pablo

    2012-01-01

    To illustrate the effect of myocardial bridges on coronary vascular tone, we describe the cases of 2 patients with different clinical presentations in the context of reproducible increased spasticity at the site of myocardial bridging. One had an episode of takotsubo cardiomyopathy, and one developed typical Prinzmetal angina while receiving desmopressin treatment for pituitary insufficiency. In both patients, acetylcholine challenge clearly revealed both the presence and the severity of myoc...

  16. Regional myocardial free fatty acid metabolism

    International Nuclear Information System (INIS)

    Experimental evidence to date has confirmed the potential value of radioactive labelled free fatty acid (FFA) and their analogs for the assessment of regional myocardial FFA metabolism despite a number of current limitations. It is emphasized that with these agents only one specific aspect of myocardial metabolism, that of FFA, can be tested and that with these compounds information on the overall metabolic state cannot always be obtained. (WU)

  17. Acute myocardial infarction following a hornet sting

    OpenAIRE

    Cvetković-Matić Danica; Ašanin Milika; Matić Dragan; Ivanović Branislava; Simić Dragan; Kalezić Nevena; Stojanov Vesna

    2009-01-01

    Background. The occurrence of an acute myocardial infarction following a hornet sting has been very rarely reported in the previous literature. Pathogenetic mechanisms include direct action of the venom components on the coronary endothelium and allergic reaction with mediators released from mast cells. The anaphylactic reaction and venom components can produce acute coronary artery thrombosis. Case report. We reported a 45-year-old man with acute myocardial infarction after a hornet sting in...

  18. Headache: A Symptom of Acute Myocardial Infarction

    OpenAIRE

    Yasmine Elgharably; Cesar Iliescu; Stefano Sdringola; Syed Wamique Yusuf

    2013-01-01

    ABSTRACT:We present a case of 55 year old man, with myocardial infarction and coronary thrombosis, whose initial presentation was with severe headache and review the literature.INTRODUCTION:Coronary ischemia typically presents with retrosternal pain that radiates to left arm (1). present atypically in various forms like indigestion (2), otalgia (3), facial pain (4) and syncope (5). Headache as the sole presentation of myocardial infarction (MI) is rare; however it has been reported previously...

  19. Improved exercise myocardial perfusion during lidoflazine therapy

    International Nuclear Information System (INIS)

    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

  20. Wall thickness measurement using resonant phenomena of circumferential Lamb waves generated by plural transducer elements located evenly on girth

    Science.gov (United States)

    Nishino, Hideo; Iwata, Kodai; Ishikawa, Masashi

    2016-07-01

    We present a novel method of measuring the pipe wall thickness using the resonance of the circumferential (C-) Lamb wave generated by a piezoelectric ring-shaped sensor (PS). The PS is a special device for an axially propagating torsional wave; however, the C-Lamb waves are generated simultaneously as spurious signals owing to the structure of the PS. Particularly under resonant conditions, the C-Lamb waves are dominantly generated, distorting the axially propagating wave. In this method, these troublesome spurious signals are used effectively for the measurement of the wall thickness under the PS location that is a dead zone of the PS itself. The method can compensate for its drawback, namely, the dead zone problem, without using additional instruments. In this study, the mechanisms of the generation and resonance of the C-Lamb waves were first explained. Secondly, the principle of the wall thickness estimation utilizing the resonance of the C-Lamb waves was proposed. Finally, experimental verifications were carried out. The estimated wall thicknesses agreed very well (maximum 1.5% error) with those measured by a micrometer caliper under suitable resonant conditions.

  1. EXPERIMENTAL RESEARCH ON AERODYNAMIC PERFORMANCE AND EXIT FLOW FIELD OF LOW PRESSURE AXIAL FLOW FAN WITH CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The aerodynamic performance of the rotors was measured. At the design condition at outlet of the rotors, detailed flow measurements were performed with a five-hole probe and a Hot-Wire Anemometer (HWA). The results show that compared to the radial rotor, the forward-skewed rotor demonstrates a wider Stable Operating Range (SOR), is able to reduce the total pressure loss in the hub region and make main loading of blade accumulating in the mid-span region. There is a wider wake in the upper mid-span region of the forward-skewed rotor. Compared to the radial rotor, in the backward-skewed rotor there is higher total pressure loss near the hub and shroud regions and lower loss in the mid-span region. In addition, the velocity deficit in the wake is lower at mid-span of the backward-skewed rotor than the forward-skewed rotor.

  2. Effect of anxiety and depression on the recurrence of persistent atrial fibrillation after circumferential pulmonary vein ablation

    Institute of Scientific and Technical Information of China (English)

    YU Sheng-bo; HU Wei; ZHAO Qing-yan; QIN Mu; HUANG He; CUI Hong-ying; HUANG Cong-xin

    2012-01-01

    Background The effects of anxiety and depression on the recurrence of persistent atrial fibrillation (AF) after circumferential pulmonary vein ablation (CPVA) are not clear.Whether CPVA can alleviate the anxiety and depression symptoms of persistent AF patients is unknown.Methods One hundred and sixty-four patients with persistent AF,of which 43 treated with CPVA (CPVA group) and 103 treated with anti-arrhythmics drugs (medicine group),were enrolled.The Zung Self-Rating Anxiety Scale (SAS),and Zung Self-Rating Depression Scale (SDS) were assessed before and 12 months after treatment in all patients.Results The scores of SAS (40.33±7.90 vs.49.76±9.52,P <0.01) and SDS (42.33±8.73 vs.48.17±8.77,P <0.01)decreased 12 months after CPVA.Over 12 months follow-up,AF relapsed in 17 patients in CPVA group.Compared with the data in the recurrent group (17 patients),the scores of SAS and SDS were significantly lower in the non-recurrent group (26 patients) at baseline.The results of multivariate Logistic regression analysis showed normal scores of SAS and SDS were the independent risk factors of AF recurrence after CPVA.Conclusions Anxiety and depression increase the recurrence risk of persistent AF after CPVA.CPVA can ameliorate the anxiety and depression symptoms in patients with persistent AF.

  3. Analysis of initiation and growth of a circumferential crack in the HDR-RPV-cylinder under pressurized thermal shock

    International Nuclear Information System (INIS)

    In order to simulate a nuclear emergency cooling situation, longterm cooling tests (pressurized thermal shocks) were carried out under normal operating conditions on the reactor pressure vessel of the HDR (hot steam reactor). Naturally occuring circumferential cracks in the cylindrical part of the RPV, previously induced during cyclic thermal shock tests, were subjected to internal pressure and thermal stresses. The aim of the test was crack initiation and a limited amount of stable crack growth. Analyses, applying fracture mechanical assessment methods, were carried out before and after the test and these checked against the experimental results. To this end, comprehensive numerical analyses, investigations into material property characteristics, non-destructive and destructive (fractographical) tests were carried out. Due to the conservative assumptions, the results of the precalculation lay on the safe side; this was intended as these results served, among other aspects, as the basis for the experimental boundary condition. The post calculation which was based on the actual crack geometry, the measured cooling medium temperature and the material properties local to the crack, was in good agreement with the experimental results. Thus a tool is now available which can be successfully applied to the assessment of cracks in reactor components. (orig.)

  4. Studies on the behavior of part-through circumferential crack at intrados in elbows under in-plane bending moment

    International Nuclear Information System (INIS)

    Highlights: → Behavior of cracked elbows with part-through crack at intrados under bending moment is studied. → Some part of crack always opens and some part gets closed irrespective of mode of applied moment. → Fraction of the crack that opens basically decides the weakening effect of the cracked elbow. → Results will be useful for fracture studies and limit load estimation especially for LBB. - Abstract: This paper presents the behavior of part-through circumferential crack at intrados in elbows under in-plane bending moment. This is based on detailed non-linear (both material and geometric) finite element analysis performed on various sizes of elbows (generally used in piping industry), having different crack sizes. It is observed that some part of the crack always opens and some part gets closed irrespective of the mode of applied bending moment (opening/closing). The fraction of the crack that opens basically decides the weakening effect of the cracked elbow. It is observed that there is a threshold value of crack length and crack depth, before which no crack opening is observed under opening mode. Also as elbow becomes thinner, the threshold value of above two parameters increases. Quite interestingly, the part of crack which closes in opening mode opens under closing mode. The above mentioned study on the behavior of crack will be useful for fracture studies and limit load estimation especially when leak before break concept is to be employed.

  5. Crack-tip Stress Field of Fully Circumferential Surface Cracked Pipe Under Combined Tension and Thermal Loads

    International Nuclear Information System (INIS)

    Under excessive plasticity, the fracture toughness of a material depends on its size and geometry. Under fully yielded conditions, the stresses in a material near its crack tip are not unique but rather depend on the geometry. Therefore, the single-parameter J-approach is limited to a high-constraint crack geometry. The JQ theory has been proposed for establishing the crack geometry constraints . This approach assumes that the crack-tip fields have two degrees of freedom. In this study, the crack-tip stress field of a fully circumferential surface-cracked pipe under combined loads is investigated on the basis of the JQ theory by using finite element analysis. The combined loads are a tensile axial force and the thermal gradient in the radial direction. Q-stresses of the crack geometry and its loading state are used to determine the constraint effects. The constraint effects of secondary loading are found to be greater than those of primary loading. Therefore, thermal shock is believed to be the most severe loading condition of constraint effects

  6. Effect of eating on thallium myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.A.; Sullivan, P.J.; Okada, R.D.; Boucher, C.A.; Morris, C.; Pohost, G.M.; Strauss, H.W.

    1986-02-01

    To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The /sup 201/Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of /sup 201/Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed /sup 201/Tl images causes increased /sup 201/Tl myocardial clearance rates and may alter /sup 201/Tl myocardial redistribution over time.

  7. Computational modeling of acute myocardial infarction.

    Science.gov (United States)

    Sáez, P; Kuhl, E

    2016-01-01

    Myocardial infarction, commonly known as heart attack, is caused by reduced blood supply and damages the heart muscle because of a lack of oxygen. Myocardial infarction initiates a cascade of biochemical and mechanical events. In the early stages, cardiomyocytes death, wall thinning, collagen degradation, and ventricular dilation are the immediate consequences of myocardial infarction. In the later stages, collagenous scar formation in the infarcted zone and hypertrophy of the non-infarcted zone are auto-regulatory mechanisms to partly correct for these events. Here we propose a computational model for the short-term adaptation after myocardial infarction using the continuum theory of multiplicative growth. Our model captures the effects of cell death initiating wall thinning, and collagen degradation initiating ventricular dilation. Our simulations agree well with clinical observations in early myocardial infarction. They represent a first step toward simulating the progression of myocardial infarction with the ultimate goal to predict the propensity toward heart failure as a function of infarct intensity, location, and size. PMID:26583449

  8. Myocardial Sleeve Tissues in Surgical Lung Specimens.

    Science.gov (United States)

    Yoshida, Akihiko; Kamata, Tsugumasa; Iwasa, Takeshi; Watanabe, Shun-ichi; Tsuta, Koji

    2015-10-01

    Left atrial myocardial extensions over the pulmonary veins (PVs), known as myocardial sleeves, are present in the physiological anatomy of most individuals. Although this structure has recently received clinical attention as a major origin of paroxysmal atrial fibrillation (AF), it has not been documented in surgical specimens. Here, we examine incidentally identified myocardial sleeve tissue in routinely processed lung resection specimens to determine its incidence and diagnostic implications. Among 694 lung resection specimens with evaluable PV margins, myocardial sleeve tissue was identified in 26 cases (3.7%). The tissue was located within the adventitia of the PVs, mostly in margin preparations, and existed outside the pericardium in the majority of cases. Carcinoma infiltration of the sleeves was evident in 6 cases. No heart injuries were observed, and no tumors invaded the heart. Preoperative electrocardiography showed sinus rhythm in all cases, whereas postoperative monitoring revealed sinus rhythm in all patients except one who showed AF and flutter. Myocardial sleeve tissue is an underrecognized incidental finding in lung resection specimens, and it is not indicative of heart injury. Cancer infiltration into this tissue indicates neither heart invasion nor, by itself, invasion into the pericardium. Although surgical transection of the myocardial sleeve did not evoke immediate arrhythmia in most cases, the overall influence of this procedure on the postsurgical risk of AF remains to be determined in further studies involving extensive rhythm assessment. PMID:26099012

  9. Effect of eating on thallium myocardial imaging

    International Nuclear Information System (INIS)

    To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The 201Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of 201Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed 201Tl images causes increased 201Tl myocardial clearance rates and may alter 201Tl myocardial redistribution over time

  10. Reverse redistribution of technetium-99m-tetrofosmin after acute coronary revascularization in patients with myocardial infarction

    International Nuclear Information System (INIS)

    This study qualified the severity and localization of reverse redistribution of technetium-99m(Tc)-tetrofosmin rest imaging. Both Tc-tetrofosmin and thallium-201 (Tl) rest imaging with early images and delayed images were obtained in the subacute phase of myocardial infarction in 21 patients with first anterior myocardial infarction and with successful transluminal angioplasty (including stenting). Relative myocardial uptake (%uptake), degree of reverse redistribution (%), and washout rate (%) were evaluated quantitatively in 6 left ventricular segments (inferoseptal, anteroseptal, anterior, anterolateral, lateral, inferolateral and inferior) by circumferential profile analysis. The percentage reverse redistribution in the infarct area was larger in Tc-tetrofosmin imaging than in Tl imaging (p=0.013). Reverse redistribution was most prominent in the anterior wall (anterior>anteroseptal>inferoseptal, p=0.020). This suggests that infradiaphragmatic scatter is unlikely as the mechanism of reverse redistribution. The washout rate of Tc-tetrofosmin in the infarct area (reverse redistribution area) was higher than that in the normal area (non-reverse redistribution area), and was also higher than the washout rate of Tl imaging in the infarct area. The %uptake of delayed images in the infarct area was larger in Tc-tetrofosmin than that in Tl imaging, whereas %uptake of early images did not differ. The percentage reverse redistribution did not correlate with the degree of collateral circulation and the residual stenosis. In conclusion, reverse redistribution of Tc-tetrofosmin was more prominent in the infarct area, and this was due to the relatively lower uptake of reverse redistribution of Tc-tetrofosmin than delayed Tl images. (author)

  11. Integrated strain array for cellular mechanobiology studies

    International Nuclear Information System (INIS)

    We have developed an integrated strain array for cell culture enabling high-throughput mechano-transduction studies. Biocompatible cell culture chambers were integrated with an acrylic pneumatic compartment and microprocessor-based control system. Each element of the array consists of a deformable membrane supported by a cylindrical pillar within a well. For user-prescribed waveforms, the annular region of the deformable membrane is pulled into the well around the pillar under vacuum, causing the pillar-supported region with cultured cells to be stretched biaxially. The optically clear device and pillar-based mechanism of operation enables imaging on standard laboratory microscopes. Straightforward fabrication utilizes off-the-shelf components, soft lithography techniques in polydimethylsiloxane and laser ablation of acrylic sheets. Proof of compatibility with basic biological assays and standard imaging equipment were accomplished by straining C2C12 skeletal myoblasts on the device for 6 h. At higher strains, cells and actin stress fibers realign with a circumferential preference

  12. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  13. Spontaneous coronary dissection associated with myocardial bridge causing acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    GE Jun-bo; HUANG Zhe-yong; LIU Xue-bo; QIAN Ju-ying

    2008-01-01

    @@ Spontaneous coronary artery dissection (SCAD) is a rare cause of myocardial ischemia, myocardial infarction and sudden cardiac death.1-10 This disease mainly occurs in young women with oral contraceptive or during the peripartum period,without risk factors for coronary artery disease.

  14. Evaluation of myocardial involvement in Duchenne's progressive muscular dystrophy with thallium-201 myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Myocardial involvement in progressive muscular dystrophy of the Duchenne type was evaluated in 19 patients using thallium-201 myocardial perfusion imaging. A qualitative analysis was performed from five projection images by three experienced physicians. Distinct perfusion defects were shown in 13 patients, especially in the LV posterolateral or posterior wall (11 patients). There was no significant relationship between the presence of perfusion defects and the skeletal muscle involvements or thoracic deformities assessed by transmission computed tomography. Extensive perfusion defects were shown in 2 patients who died of congestive heart failure 1 to 2 years after the scintigraphic study. Progression of the myocardial scintigraphic abnormalities were considered to be minimal in 7 of 9 patients who underwent two serial scintigraphic studies over 2 to 3 years. It was concluded that thallium myocardial perfusion imaging is a useful clinical technique to assess myocardial involvement in Duchenne's progressive muscular dystrophy. (author)

  15. Prognostic significance of transient myocardial ischaemia after first acute myocardial infarction: five year follow up study

    DEFF Research Database (Denmark)

    Mickley, H; Nielsen, J R; Berning, J;

    1995-01-01

    OBJECTIVE: To assess the five year prognostic significance of transient myocardial ischaemia on ambulatory monitoring after a first acute myocardial infarction, and to compare the diagnostic and long term prognostic value of ambulatory ST segment monitoring, maximal exercise testing, and...... infarction. MAIN OUTCOME MEASURES: Relation of ambulatory ST segment depression, exercise test variables, and left ventricular ejection fraction to subsequent objective (cardiac death or myocardial infarction) or subjective (need for coronary revascularisation) events. RESULTS: 23 of the 123 patients had...... a first myocardial infarction who can perform exercise tests before discharge. Patients at high risk of future myocardial infarction or death from cardiac causes are not identified. Ambulatory monitoring and exertional angina distinguish a small subset of patients who will develop severe angina...

  16. Investigation on Effect of Distance Between Two Collinear Circumferential Surface Cracks on Primary Water Stress Corrosion Crack Growth in Alloy 600TT Steam Generator Tubes

    International Nuclear Information System (INIS)

    The study investigated the effect of the distance between two collinear circumferential surface cracks on the primary stress corrosion crack (PWSCC) growth in alloy 600TT steam generator tubes using a finite element damage analysis based on the PWSCC initiation model and macroscopic phenomenological damage mechanics approach. The damage analysis method was verified by comparing the results to the previous study results. The verified method was applied to collinear circumferential surface PWSCCs. As a result, it was found that the collinear cracks showed earlier coalescence and penetration times than the a single crack, and the times increased with the distance. In addition, it is expected that penetration may occur before coalescence of two cracks if they are more than a specific distance apart

  17. Flaw Inspection of Aluminum Pipes by Non-Contact Visualization of Circumferential Guided Waves using Laser Ultrasound Generation and an Air-Coupled Sensor

    International Nuclear Information System (INIS)

    Our group had previously proposed a generation laser scanning system for visualizing ultrasound propagation on an object as an animate image, which provided visible and quick flaw inspection. Recently, we improved this system to make it completely non-contact by employing an air-coupled ultrasound transducer as a receiver instead of a contact transducer, and demonstrated the successful visualization of Lamb waves propagating on aluminum and carbon fiber reinforced plastic plates, as well as the detection of flaws. In this research, we applied this system to the non-contact visualization of circumferential guided waves on aluminum pipes. It was shown that circumferential guided waves propagating in opposite directions could be visualized separately, and that a flaw such as a slit or thinning on the inside surface of the pipe could be successfully detected even when it existed outside the scanning area

  18. Investigation on ductile fracture behavior of 3-inch diameter Type 304 stainless steel pipe with a circumferential through-wall crack

    International Nuclear Information System (INIS)

    At Japan Atomic Energy Research Institute (JAERI), a pipe fracture test program has been conducted as a part of the Leak-Before-Break (LBB) verification research in LWR pressure boundary pipings. In this program, fracture behavior and fracture criteria of the circumferentially cracked pipe have been investigated, using austenitic stainless steel pipes and carbon steel pipes. This report presents a four-point bending test results of 3-inch diameter Type 304 austenitic stainless steel pipes with circumferential through-wall crack at room temperature. Pipe fracture data were obtained from the test in regard to load-loadline displacement, crack extension, crack opening area, and so on. Discussions are performed on the effect of pipe ovalization ratio at maximum load, the application of the net-section collapse criterion, and the effect of initial crack angle, wall-thickness etc. on J-R curve. Furthermore, the crack opening area was estimated by assuming a simple crack model. (author)

  19. Assessment of myocardial damage in hypertrophic cardiomyopathy using cardiac enzymes, myosin light chain and myocardial scintigraphy

    International Nuclear Information System (INIS)

    To assess myocardial damage in hypertrophic cardiomyopathy (HCM), CPK-MB, %LDH 1, myoglobin (Mb), and myosin light chain (MLC) were determined in 45 HCM patients. Of these patients, 10 also underwent Tl-201 myocardial scintigraphy and In-111-antimyosin antibody (In-111 Fab-DTPA)(In-AM) myocardial scintigraphy. MLC was 0.56±0.55 ng/ml. An increase in CPK-MB, %LDH 1, and Mb was seen in 6 (14%), 19 (44%), and 7 (18%) patients, respectively. There was no correlation between MLC and any of CPK-MB, %LDH1 or Mb. Perfusion defects were seen on Tl-201 myocardial scintigrams in 4 patients. All of these patients had diffuse tracer uptake on In-AM myocardial scintigrams. The degree of In-AM uptake was not correlated with MLC; however, of 4 patients with intense In-AM uptake, 3 had perfusion defects on Tl-201 myocardial scintigrams and decreased left ventricular function. In 3 patients in whom CPK-MB and %LDH 1 were increased but MLC was not increased, diffuse tracer uptake was seen on In-AM myocardial scintigrams. Because diffuse uptake of In-AM was seen in spite of the lack of increased MLC, In-111-Fab-DTPA is likely to be incorporated by the myocardial damaged cells, as well as necrotic cells. HCM seems to be associated with a high likelihood of myocardial damage. Integrated assessment of myocardial damage is required, including an increase of MLC, CPK-MB, %LDH 1, and Mb, perfusion defects on Tl-201 scintigrams, and tracer uptake on In-AM scintigrams. (N.K.)

  20. Current status of CHF predictions using CFD modeling technique and review of other techniques especially for non-uniform axial and circumferential heating profiles

    International Nuclear Information System (INIS)

    Highlights: • Current status of CHF predictions using CFD modeling technique. • Review of other techniques for non-uniform axial and circumferential heating profiles. • Heat transfer and wall boiling modeling are also clearly described. • Detailed description of numerical models used in two-phase flow boiling predictions. • Most of the numerical works done for predictions of CHF in literature are addressed. - Abstract: Trusted predictions of critical heat flux (CHF) value are essential for safe operation of boilers, steam generators and nuclear power reactors. Prediction techniques are numerous but they are mostly limited to uniformly heated tubes. There are separated effects on CHF, such as axial and radial heat flux distributions that have not been taken much attention. These effects are encountered during operation of boilers/steam generators and nuclear reactors. The present work is aimed at providing detailed analysis for experimental and numerical techniques used in CHF predictions focusing on non-uniform axial and circumferential heating profiles. For this purpose, heat transfer characteristics in case of CHF and heat transfer and wall boiling modeling are also clearly described. In addition, a detailed description of numerical models used in the predictions of the two phase flow characteristics is also presented followed by addressing most of the numerical work done for predictions of CHF in literature. Due to new challenges presented by the non-uniform heating in axial and circumferential directions, research work pertaining to analysis of CHF predictions in real systems for non-uniform heating profiles in both axial and circumferential directions is also presented

  1. The "open book" flap: a heterodigital cross-finger skin flap and adipofascial flap for coverage of a circumferential soft tissue defect of a digit.

    Science.gov (United States)

    Tadiparthi, S; Akali, A; Felberg, L

    2009-02-01

    A case of circumferential digital skin loss with exposed tendons from the proximal phalanx to the distal interphalangeal joint is presented. This was treated with a two-layer heterodigital cross-finger ("open book") flap from the adjacent digit, utilising a skin-only cross-finger flap to cover the palmar defect and an adipofascial flap to cover the dorsal defect. PMID:19129359

  2. Leakage Failure Reason Analysis of Circumferential Weld for Natural Gas Pipeline%天然气输送管道环焊缝泄漏失效分析

    Institute of Scientific and Technical Information of China (English)

    胡美娟; 刘迎来; 朱丽霞; 齐丽华; 杨放

    2014-01-01

    通过断口形貌、金相分析以及力学性能检测等方法对某X80天然气输送管道环焊缝泄漏产生的原因进行了失效分析。分析结果表明,环焊缝焊接接头的拉伸性能符合Q/SY GJX 0110-2007《西气东输二线管道工程线路焊接技术规范》要求,但焊缝和热影响区的冲击性能均未达到焊接技术规范的要求,管道环焊缝泄漏裂纹位于环焊缝6点位置根焊区域,此位置根焊进行过内补焊作业,补焊焊缝焊趾处存在的焊接缺陷是环焊缝开裂泄漏的主要原因。%The leakage failure reason of circumferential weld for some X80 natural gas pipeline was analyzed by means of fracture morphology, microstructure observation and mechanical properties tests. The results showed that the tensile performance of welded joint for circumferential weld accord with the requirements of Q/SY GJX 0110-2007 Welding Technology Specification for the Second West-to-East Gas Pipeline Project, and the impact toughness of weld and HAZ both fail to meet the welding requirements of technical specification. The leaking crack of circumferential weld lies in the six position of root welding zone, and repair welding was implemented in the six position of root welding. The main leakage failure reason of circumferential weld was the welding defects close to the toe zone of the repair welding.

  3. Stress Intensity Factor for a Circumferential Crack in a Finite-Length Thin to Thick Walled Cylinder under an Arbitrary Biquadratic Stress Distribution on the Crack Surfaces

    OpenAIRE

    MESHII, Toshiyuki; WATANABE, Katsuhiko

    2001-01-01

    This paper presents the development of a practical method, by using prepared tabulated data, tocalculate the mode I stress intensity factor (SIF) for an inner surface circumferential crack in a finitelength cylinder. The crack surfaces are subjected to an axisymmetric stress with an arbitrary biquadraticradial distribution. The method was derived by applying the authors’ weight function for the crack. Thiswork is based on the thin shell theory and the Petroski-Achenbach method. Our method is ...

  4. [Occupational stress and myocardial infarction].

    Science.gov (United States)

    Consoli, Silla M

    2015-01-01

    Besides the best-known role of depressed mood, occupational stress deserves to be taken as a coronary risk factor. There are two basic models to define occupational stress: Karasek's model (high job psychological demands associated with low decision latitude, or even low social support at work) and Siegrist's model (imbalance between efforts and rewards received). The combination of the two models better reflects the coronary risk than each model alone. Occupational stress appears both as a risk factor and a prognostic factor after the occurrence of myocardial infarction. The relevance of the models is best in men or in younger age subjects. In women, role conflicts (occupational/domestic), the existence of excessive "intrinsic" efforts (job over investment) and association with marital stress provide more specific information. Burnout, particularly among health professionals, and bullying at work are also linked to cardiovascular risk. Occupational stress is a collective indicator of health at work, valuable to the employer. At an individual level, it can lead to therapeutic preventive approaches. PMID:26150284

  5. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Iannicelli, Elsa; Di Renzo, Sara [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ferri, Mario [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Pilozzi, Emanuela [Department of Clinical and Molecular Sciences, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Di Girolamo, Marco; Sapori, Alessandra [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ziparo, Vincenzo [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); David, Vincenzo [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy)

    2014-07-01

    To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.

  6. Sparing Sphincters and Laparoscopic Resection Improve Survival by Optimizing the Circumferential Resection Margin in Rectal Cancer Patients.

    Science.gov (United States)

    Keskin, Metin; Bayraktar, Adem; Sivirikoz, Emre; Yegen, Gülcin; Karip, Bora; Saglam, Esra; Bulut, Mehmet Türker; Balik, Emre

    2016-02-01

    The goal of rectal cancer treatment is to minimize the local recurrence rate and extend the disease-free survival period and survival. For this aim, obtainment of negative circumferential radial margin (CRM) plays an important role. This study evaluated predictive factors for positive CRM status and its effect on patient survival in mid- and distal rectal tumors.Patients who underwent curative resection for rectal cancer were included. The main factors were demographic data, tumor location, surgical technique, neoadjuvant therapy, tumor diameter, tumor depth, lymph node metastasis, mesorectal integrity, CRM, the rate of local recurrence, distant metastasis, and overall and disease-free survival. Statistical analyses were performed by using the Chi-squared test, Fisher exact test, Student t test, Mann-Whitney U test and the Mantel-Cox log-rank sum test.A total of 420 patients were included, 232 (55%) of whom were male. We observed no significant differences in patient characteristics or surgical treatment between the patients who had positive CRM and who had negative CRM, but a higher positive CRM rate was observed in patients undergone abdominoperineal resection (APR) (P CRM status. Logistic regression analysis revealed that APR (P CRM status. Moreover, positive CRM was associated with decreased 5-year overall and disease-free survival (P = 0.002 and P = 0.004, respectively).This large single-institution series demonstrated that APR and open resection were independent predictive factors for positive CRM status in rectal cancer. Positive CRM independently decreased the 5-year overall and disease-free survival rates. PMID:26844498

  7. Crack-tip constraint analyses and constraint-dependent LBB curves for circumferential through-wall cracked pipes

    International Nuclear Information System (INIS)

    Highlights: • Solution of constraint parameter τ* for through-wall cracked pipes has been obtained. • Constraint increases with increasing crack length and radius–thickness ratio of pipes. • Constraint-dependent LBB curve for through-wall cracked pipes has been constructed. • For increasing accuracy of LBB assessments, constraint effect should be considered. - Abstract: The leak-before-break (LBB) concept has been widely applied in the structural integrity assessments of pressured pipes in nuclear power plants. However, the crack-tip constraint effects in LBB analyses and designs cannot be incorporated. In this paper, by using three-dimensional finite element calculations, the modified load-independent T-stress constraint parameter τ* for circumferential through-wall cracked pipes with different geometries and crack sizes has been analyzed under different loading conditions, and the solutions of the crack-tip constraint parameter τ* have been obtained. Based on the τ* solutions and constraint-dependent J–R curves of a steel, the constraint-dependent LBB (leak-before-break) curves have been constructed. The results show that the constraint τ* increases with increasing crack length θ, mean radius Rm and radius–thickness ratio Rm/t of the pipes. In LBB analyses, the critical crack length calculated by the J–R curve of the standard high constraint specimen for pipes with shorter cracks is over-conservative, and the degree of conservatism increases with decreasing crack length θ, Rm and Rm/t. Therefore, the constraint-dependent LBB curves should be constructed to modify the over-conservatism and increase accuracy of LBB assessments

  8. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    International Nuclear Information System (INIS)

    To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting

  9. Circumferential creep properties of stress-relieved Zircaloy-4 and Zr-Nb-Sn-Fe cladding tubes

    International Nuclear Information System (INIS)

    In this study, the circumferential creep behaviors of stress-relieved Zircaloy-4 and Zr-Nb-Sn-Fe alloys were investigated. The out-of reactor creep resistance of Zircaloy-4 was found to be better than that of the Zr-Nb-Sn-Fe alloy in the temperature and stress range of this study, suggesting that the solution strengthening effect of Sn is more effective in restraining dislocation motion than the precipitate strengthening effect of Nb. Zircaloy-4 and Zr-Nb-Sn-Fe have stress exponents between 6.5 and 7.5 in the lower stress region. The stress exponent decreased to about 3 for Zircaloy-4 and to about 4.2 for Zr-Nb-Sn-Fe in the high stress region. The activation energy increased from 240 to 270 kJ/mol for Zircaloy-4 and Zr-Nb-Sn-Fe as the applied stress increased from 80 to 150 MPa. The creep activation energy observed in this study is close to those of creep for Zircaloy-2 and Zr. The lower stress exponent in the higher stress region for Zircaloy-4 with a relatively higher Sn content compared to Zr-Nb-Sn-Fe alloy may be supported by the fact that the drag force of Sn atoms acting on dislocations increases with increase of Sn content. Larson-Miller Parameter (LMP) decreased with the increase of applied stress, and Zircaloy-4 has a higher LMP than the Zr-Nb-Sn-Fe alloy, compatible with the lower creep rate in Zircaloy-4.

  10. Secondary prevention with calcium antagonists after acute myocardial infarction

    DEFF Research Database (Denmark)

    Hansen, J F

    1992-01-01

    Experimental studies have demonstrated that the 3 calcium antagonists nifedipine, diltiazem, and verapamil have a comparable effect in the prevention of myocardial damage during ischaemia. Secondary prevention trials after acute myocardial infarction, which aimed at improving survival and...

  11. Stress myocardial scintigraphy in coronary artery disease

    International Nuclear Information System (INIS)

    To evaluate the clinical significance of asymptomatic ischemic heart disease, exercise electrocardiography and stress myocardial scintigraphy were performed. These were correlated with symptoms during exercise tests and histories of myocardial infarction (MI). The study subjects consisted of 70 patients with coronary artery disease, including 34 with MI, and 36 without MI but with angina pectoris. Stress tests were performed using bicycle ergometer under electrocardiographic monitoring throughout the test. Transient myocardial ischemia was confirmed by perfusion defects on thallium myocardial imaging demonstrated immediately after exercise, but not 3 hours after the stress test. Asymptomatic ST depression was observed in 18 of 34 patients with MI (53%) and in 21 of the 36 patients with angina (58%); however, transient myocardial perfusion defects were confimred in 61% of the patients with MI (11 of 18 patients), but in only 33% of those with angina (7 of 21 patients). The difference was statistically significant (p<0.05). It was suggested that there are some differences in the clinical significance of asymptomatic ST depression between the patients with MI and those without MI but with angina pectoris. (author)

  12. Changes of myocardial glucose metabolism by starvation

    International Nuclear Information System (INIS)

    Ischemic heart disease (IHD) is a fatal disease and high food intake is thought one of the important risk factor for IHD. Biochemical analyse of the relation between food and IHD is necessary. F-18-labeled 2-deoxy-glucose (FDG) is useful pharmaceutical for detection of myocardial glucose metabolism. The effect of starvation on myocardial uptake and retention of FDG was investigated. Control rats which were fed ad libitum were killed 10, 30, 60 and 120 minutes after the injection of FDG (10 uCi). The other rats were starved for 12, 24, 36 and 48 hours each. The rats were killed 30 minutes after the injection of FDG. Myocardial uptakes of FDG were high enough 30 minutes after the injection of FDG. Decrease of myocardial uptake was showed in 12 hours starvation alrealdy and decrease was greater according to the starvation time. From this result myocardial glucose metabolism is considered to be suppressed early stage of starvation another energy metabolic pathway is considered to be used

  13. Abnormal ventricular repolarisation in association with myocardial bridging.

    OpenAIRE

    J.W. DEAN; Mills, P G

    1994-01-01

    Myocardial bridging causing systolic compression of epicardial coronary arteries may be an incidental finding at coronary arteriography. Bridging rarely causes myocardial ischaemia. A young man presented with chest pain and striking abnormalities of ventricular repolarisation that initially were treated as myocardial infarction. At cardiac catheterisation the coronary arteries were normal apart from the presence of a myocardial bridge affecting a major diagonal branch of the left anterior des...

  14. Effect of combined Antioxidants on Acute Myocardial infarction size

    OpenAIRE

    B.Farahani; K.Hadiyan; A.Mohseni

    2001-01-01

    SummaryBackground and purpose : The role of oxygen-derived free radicals in destruction of myocardial cells during acute ischemia or reperfusion has been proved. This phenomenon made the workers to study and find the inhibitory therapeutic methods in order to reduce the myocardial cell destruction during acute myocardial infarction. This study evaluates the role of combined antioxidants on acute myocardial infarction sige in patients referring to vali asr hospital of Arak.Materials and Method...

  15. The May 2005 eruption of Fernandina volcano, Galápagos: The first circumferential dike intrusion observed by GPS and InSAR

    KAUST Repository

    Chadwick, William W Jr

    2010-12-15

    The May 2005 eruption of Fernandina volcano, Galápagos, occurred along circumferential fissures parallel to the caldera rim and fed lava flows down the steep southwestern slope of the volcano for several weeks. This was the first circumferential dike intrusion ever observed by both InSAR and GPS measurements and thus provides an opportunity to determine the subsurface geometry of these enigmatic structures that are common on Galápagos volcanoes but are rare elsewhere. Pre- and post- eruption ground deformation between 2002 and 2006 can be modeled by the inflation of two separate magma reservoirs beneath the caldera: a shallow sill at ~1 km depth and a deeper point-source at ~5 km depth, and we infer that this system also existed at the time of the 2005 eruption. The co-eruption deformation is dominated by uplift near the 2005 eruptive fissures, superimposed on a broad subsidence centered on the caldera. Modeling of the co-eruption deformation was performed by including various combinations of planar dislocations to simulate the 2005 circumferential dike intrusion. We found that a single planar dike could not match both the InSAR and GPS data. Our best-fit model includes three planar dikes connected along hinge lines to simulate a curved concave shell that is steeply dipping (~45-60°) toward the caldera at the surface and more gently dipping (~12-14°) at depth where it connects to the horizontal sub-caldera sill. The shallow sill is underlain by the deep point source. The geometry of this modeled magmatic system is consistent with the petrology of Fernandina lavas, which suggest that circumferential eruptions tap the shallowest parts of the system, whereas radial eruptions are fed from deeper levels. The recent history of eruptions at Fernandina is also consistent with the idea that circumferential and radial intrusions are sometimes in a stress-feedback relationship and alternate in time with one another. © 2010 Springer-Verlag.

  16. Non-invasive imaging in detecting myocardial viability: Myocardial function versus perfusion

    Directory of Open Access Journals (Sweden)

    Iqbal A. Elfigih

    2014-12-01

    Full Text Available Coronary artery disease (CAD is the most prevalent and single most common cause of morbidity and mortality [1] with the resulting left ventricular (LV dysfunction an important complication. The distinction between viable and non-viable myocardium in patients with LV dysfunction is a clinically important issue among possible candidates for myocardial revascularization. Several available non-invasive techniques are used to detect and assess ischemia and myocardial viability. These techniques include echocardiography, radionuclide images, cardiac magnetic resonance imaging and recently myocardial computed tomography perfusion imaging. This review aims to distinguish between the available non-invasive imaging techniques in detecting signs of functional and perfusion viability and identify those which have the most clinical relevance in detecting myocardial viability in patients with CAD and chronic ischemic LV dysfunction. The most current available studies showed that both myocardial perfusion and function based on non-invasive imaging have high sensitivity with however wide range of specificity for detecting myocardial viability. Both perfusion and function imaging modalities provide complementary information about myocardial viability and no optimum single imaging technique exists that can provide very accurate diagnostic and prognostic viability assessment. The weight of the body of evidence suggested that non-invasive imaging can help in guiding therapeutic decision making in patients with LV dysfunction.

  17. Assessment of myocardial viability using multidetector computed tomography in patients with reperfused acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. [Department of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Choi, B.J. [Department of Cardiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Kang, D.K., E-mail: kdklsm@ajou.ac.kr [Department of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Sun, J.S. [Department of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of)

    2012-08-15

    Aim: To assess the prognostic value of 64-section multidetector computed tomography (MDCT) to predict follow-up myocardial dysfunction and functional recovery after reperfusion therapy in patients with acute myocardial infarction (MI) as defined by echocardiography. Materials and methods: After reperfusion therapy for acute MI, 71 patients underwent two-phase contrast-enhanced MDCT and follow-up echocardiography. MDCT findings were compared with echocardiographic findings using kappa statistics. The areas under the receiver operating characteristic curves (AUCs) and the odds ratios (ORs) of early perfusion defects (EPD), delayed enhancement (DE), and residual perfusion defects (RPD) for predicting follow-up myocardial dysfunction and functional recovery were calculated on a segmental basis. Results: The presence of transmural EPD (EPD{sub TM}) or RPD showed good agreement (k = 0.611 and 0.658, respectively) with follow-up myocardial dysfunction, while subendocardial EPD (EPD{sub sub}) or subendocardial DE (DE{sub sub}) showed fair agreement with follow-up myocardial dysfunction (k = 0.235 and 0.234, respectively). The AUC of RPD (0.796) was superior (p < 0.001 and 0.031, respectively) to those of EPD{sub TM} (0.761) and DE{sub TM} (0.771). The presence of EPD{sub TM}, DE{sub TM}, and RPD were significant, independent positive predictors of follow-up myocardial dysfunction (OR = 6.4, 1.9, and 9.8, respectively). EPD{sub TM} was a significant, independent negative predictor of myocardial functional recovery (OR = 0.13). Conclusion: Abnormal myocardial attenuation on two-phase MDCT after reperfusion therapy may provide promising information regarding myocardial viability in patients with acute MI.

  18. RAMIPRIL IN THERAPY OF PATIENTS AFTER MYOCARDIAL INFARCTION

    OpenAIRE

    I. V. Szirov; E. V. Malichenko

    2015-01-01

    Angiotensin converting enzyme inhibitors are the first line medicine for the treatment of the most of cardiovascular diseases. There is no class-effect for these drugs in myocardial infarction therapy. Moreover in myocardial infarction angiotensin converting enzyme inhibitors have significant intra-group differences. Ramipril is the one of the most studied drug of this group recommended for patients after acute myocardial infarction.

  19. Perfusion scintigraphy in acute myocardial infarction

    International Nuclear Information System (INIS)

    The Tc-99m sestamibi perfusion SPECT scintigraphy in acute myocardial infarction is a feasible method to assess the size of area at risk and the residual blood flow to this area as the most important determinants of final infarct size without any delay in treatment. In combination with a follow-up study final infarct size as well as myocardial salvage can be quantified. Clinical indications for the use of Tc-99m sestamibi scintigraphy are the noninvasive identification of arterial occlusion in patients suspected to acute myocardial infarction without electrocardiographic ST-elevation and the assessment of reperfusion success. In clinical trials Tc-99m sestamibi scintigraphy has proven to be a useful method to assess the impact of varying reperfusion therapies. The present review article discusses the indication, the study protocol, the interpretation of results and the clinical and scientifically importance of this method. (orig.)

  20. Hypoplasia of exocrine pancreas with myocardial necrosis

    Institute of Scientific and Technical Information of China (English)

    Xiang Sheng Zhang; Xin Xiu Xu; Yan Zhang; Sbu Hua Wu

    2000-01-01

    AIM To study the clinical and pathological features of hypoplasia of exocrine pancreas with myocardialnecrosis.METHODS One ease of hypoplasia of exocrine pancreas with myocardial necrosis was autopsied. Theclinical signs and pathological changes were analyzed.RESULTS A 15-month-old boy with hypoplasia of exocrine pancreas was reported. The main clinicalfeatures were steatorrhea and marked underdevelopment. He died of acute heart failure afterhospitalization. Autopsy showed that there were aplasia of exocrine portion and fatty metaplasia ofpancreas, the myocardium revealed focal necrosis and sear formation.CONCLUSION Atrophy of exocrine pancreas and myocardial necrosis exist at the same time, suggestingthat there may be some relationship between them. It was likely that the damaged pancreatic tissue releasedsome active materials that may harm the myocardium or decrease pancreatic juice that results in lack ofnutrient and myocardial necrosis.

  1. Acute myocardial infarction in a young patient

    International Nuclear Information System (INIS)

    Myocardial infarction (MI) is considered to be the disease of the fifth and sixth decade as seen in the West but an earlier age incidence is not infrequently encountered in the South Asian population. However, occurrence of MI in the teen-age still remains a rare happening. We are reporting a case of a teenager, who suffered a myocardial infarction with cardiogenic shock and pulmonary edema on two separate occasions with ECG and biochemical evidence of myocardial infarction. An exercise stress test done in between the two episodes was negative at a workload of 13.5 METs. A coronary angiogram done after the second event revealed normal coronary arteries and a preserved left ventricular systolic and segmental function. Except for low HDL (high density lipoprotein) and mildly raised homocysteine levels, the patient did not have other conventional or novel risk factors for coronary artery disease. (author)

  2. Rationale and radiopharmaceuticals for myocardial imaging

    International Nuclear Information System (INIS)

    Static radionuclide imaging procedures are now available for evaluating regional myocardial perfusion and for detecting acute myocardial infarction. Thallium-201, a radiopharmaceutical which possesses many of the characteristics of potassium analogs, at present is receiving the greatest attention as a regional blood flow indicator. Ischemic lesions appear as areas of decreased tracer uptake. Unfortunately, this agent is expensive, is in limited supply and has a photopeak which is low for optimum imaging. Positive infarct images can be obtained with various technetium-99m chelates. Pyrophosphate appears to be the best of the technetium compounds studied to date although the mechanism of uptake of the chelates has not yet been fully elucidated. Therefore, quantitative measurements of infarct size are not justified. As perfusion imaging and infarct imaging provide useful, complementary data, a dual tracer approach to evaluating patients with suspected coronary artery disease and/or myocardial infarction is probably justifiable

  3. Nitroglycerine induced acute myocardial infarction in a patient with myocardial bridging

    DEFF Research Database (Denmark)

    Rujic, Dragana; Nielsen, Mette Lundgren; Veien, Karsten Tange;

    2014-01-01

    Muscle overlying an intramyocardial segment of a coronary artery is termed a myocardial bridge. The intramyocardial segment, the tunneled artery, is compressed during systole. The condition is generally benign but may occasionally cause myocardial ischemia, infarction, arrhythmia, or sudden cardiac...... death. We present a case regarding a 52-year-old man with exercise-induced angina who was diagnosed with a myocardial bridge overlying the left anterior descending artery. He was initially treated with beta-blockers and later received coronary bypass graft surgery....

  4. Association between coronary flow reserve, left ventricular systolic function, and myocardial viability in acute myocardial infarction

    DEFF Research Database (Denmark)

    Løgstrup, Brian Bridal; Høfsten, Dan E; Christophersen, Thomas B;

    2010-01-01

    AIMS: To investigate the relationships between coronary flow reserve (CFR), left ventricular (LV) systolic function, and myocardial viability in patients with acute myocardial infarction (AMI). METHODS AND RESULTS: In 149 patients with a first AMI, we estimated CFR non-invasively and assessed LV...... patients with CFR 2, P < 0.0001. CONCLUSION: Resting echocardiographic parameters were similar in patient groups. During LDDE, patients with reduced CFR had increased LV size and compromised longitudinal function of LV and were less likely to have evidence of myocardial viability....

  5. Myocardial performance index: prediction and monitoring of remodeling and functioning of the left ventricle after first myocardial infarction

    OpenAIRE

    Ćelić Vera; Dekleva Milica; Majstorović Anka; Radivojević Nenad; Kostić Nada; Čaparević Zorica

    2010-01-01

    Introduction. Dynamic changing of left ventricular geometry and contractile state after acute myocardial infarction is responsible for various aspects of left ventricular remodeling and dysfunction. A number of studies have shown that myocardial performance index allows prediction of acute myocardial infarction complications. The objective of our study was to determine the power of myocardial performance index to predict and assess the severity of left ventricular remodeling, systolic and dia...

  6. Asymptomatic myocardial ischemia following cold provocation

    International Nuclear Information System (INIS)

    Cold is thought to provoke angina in patients with coronary disease either by an increase in myocardial demand or an increase in coronary vascular resistance. We investigated and compared the effects of cold pressor stimulation and symptom-limited supine bicycle exercise on regional myocardial perfusion in 35 patients with stable angina and coronary disease and in 10 normal subjects. Regional myocardial perfusion was assessed with positron emission tomography and rubidium-82. Following cold pressor stimulation 24 of 35 patients demonstrated significant abnormalities of regional myocardial perfusion with reduced cation uptake in affected regions of myocardium: 52 +/- 9 to 43 +/- 9 (p less than 0.001 vs normal subjects). Among these 24 patients only nine developed ST depression and only seven had angina. In contrast, 29 of 35 patients underwent supine exercise, and abnormal regional myocardial perfusion occurred in all 29, with a reduction in cation intake from 48 +/- 10 to 43 +/- 14 (p less than 0.001 vs normal subjects). Angina was present in 27 of 29 and ST depression in 25 of 29. Although the absolute decrease in cation uptake was somewhat greater following cold as opposed to exercise, the peak heart rate after cold was significantly lower than that after exercise (82 +/- 12 vs 108 +/- 16 bpm, p less than 0.05). Peak systolic blood pressures after cold and exercise were similar (159 +/- 24 vs 158 +/- 28). Thus, cold produces much more frequent asymptomatic disturbances of regional myocardial perfusion in patients with stable angina and coronary disease than is suggested by pain or ECG changes

  7. Second trimester ultrasound: reference values for two-dimensional speckle tracking-derived longitudinal strain, strain rate and time to peak deformation of the fetal heart

    NARCIS (Netherlands)

    Kapusta, L.; Mainzer, G.; Weiner, Z.; Deutsch, L.; Khoury, A.; Haddad, S.; Lorber, A.

    2012-01-01

    BACKGROUND: Data on myocardial deformation during the internationally widely used second-trimester screening are scarce and confusing. Reference values of time to peak strain are missing. The aims of this study were to assess reference values derived from two-dimensional speckle-tracking echocardiog

  8. Myocardial bridges: morphological and functional aspects.

    OpenAIRE

    A.G. Ferreira; Trotter, S E; König, B; Décourt, L V; Fox, K; Olsen, E G

    1991-01-01

    OBJECTIVE--To assess the arrangement of myocardial bridges. DESIGN--A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS--Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further with a magnifying glass. Two different types of muscle bridges could be identified. Thirty one of...

  9. Acute myopericarditis masquerading as acute myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    Wen Tian; Zixin Zhang; Xiaojuan Bai; Dingyin Zeng; Guoxian Qi

    2008-01-01

    Patients with abrupt onset of chest pain, ischemic ECG abnormalities and elevated levels of cardiac markers could be given a diagnosis of acute myocardial infarction. However, some other diseases should be taken into consideration in this clinical setting when coronary arteries are proven to be normal. Here we report a case of acute myopericarditis with clinical presentation of myocardial infarction and normal coronary anatomy. The Herpes Simplex Virus Ⅱ was considered as the organism causing myopericarditis and the patient was recovered by the treatment with valacicloavir. A precise diagnosis is a prerequisite of successful treatment and favorable prognosis.

  10. MYOCARDIAL REMODELING IN ISCHEMIC HEART DISEASE

    OpenAIRE

    A.N. Zakirova; R.G. Oganov; N.E. Zakirova; G. R. Klochkova; F.S. Musina

    2016-01-01

    Aim. To study the myocardial remodeling features in patients with stable angina depending on disease severity and experienced myocardial infarction (MI).Material and methods. 148 male patients with stable angina were examined and randomized into 3 groups (G1-G3). 52 patients of G1 had angina of I-II functional class (FC). 49 patients of G2 had angina of III FC, and 47 patients of G3 had angina of IV FC. History of MI had 79,5, 87.2 and 92.6% of patients in G1, G2 and G3 respectively. 35 healt...

  11. Physical Activitiea Associted with Angina Pectoris Before Myocardial Infarction and the Onset of Myocardial Infarction

    OpenAIRE

    Matsuda, Masako

    1984-01-01

    One hundred and ninety-seven patients with a history of myocardeal infarction were interviewed to evaluate the incidence of angina pectoris and the physical activity precipitating angina before myocardial infarction, and the mode of physical activity at the onset of myocardial infarction. Ninety-ewo patients had no angina before infarction, whereas 105 did, In 105 patients, 58 had a chronic stable angina without a change of pattern of angina before infarction, while 22 noticed worsening of th...

  12. Acute myocardial infarction in a young adult with myocardial bridging and normal coronary arteries

    OpenAIRE

    Moris Chansky; Adriana Regina Perez; Nilo Lima

    2004-01-01

    The authors present a case of a young adult with acute myocardialinfarction, attended at the Emergency Department of HospitalIsraelita Albert Einstein. Acute myocardial infarction caused bymyocardial bridge (intramyocardial tunneled coronary artery) is arare clinical entity. The finding of this condition in patients withnormal arteries (non-obstructed vessels) is uncommon; it isusually associated with extracardiac triggering factors. The casereported presented an acute myocardial infarction c...

  13. Myocardial Ischemia: Lack of Coronary Blood Flow or Myocardial Oxygen Supply/Demand Imbalance?

    Science.gov (United States)

    Heusch, Gerd

    2016-07-01

    Regional myocardial blood flow and contractile function in ischemic myocardium are well matched, and there is no evidence for an oxygen supply/demand imbalance. Thus, myocardial ischemia is lack of coronary blood flow with electric, functional, metabolic, and structural consequences for the myocardium. All therapeutic interventions must aim to improve blood flow to ischemic myocardium as much and as quickly as possible. PMID:27390331

  14. Influences of percutaneous coronary intervention on myocardial activity in myocardial infarction patients with different viable myocardium

    Institute of Scientific and Technical Information of China (English)

    李丽琪

    2013-01-01

    Objective To evaluate the effect of percutaneous coronary intervention (PCI) on left ventricular function in patients with different types of myocardial infarction and to explore the correlation factors for the left ventricular function.Methods A total of 43 patients diagnosed as acute myocardial infarction were enrolled in this study.The perfusion and delayed enhancement magnetic resonance imaging (DE-MRI) was applied to observe the fol-

  15. Inducible myocardial ischaemia diagnosed using computed tomography dipyridamole stress myocardial perfusion technique

    International Nuclear Information System (INIS)

    Improved multi-detector computed tomography (MDCT) temporal and spatial resolution allows for the assessment of coronary artery disease, left ventricular systolic function and resting myocardial perfusion defects with high sensitivity and specificity. Here we present a case using a novel combination technique of cardiac computed tomography scanning with dipyridamole stress for the detection of functionally significant coronary disease, and demonstrate that dipyridamole-induced myocardial ischaemia is both detectable and quantifiable by cardiac MDCT.

  16. Flow propagation velocity is not a simple index of diastolic function in early filling. A comparative study of early diastolic strain rate and strain rate propagation, flow and flow propagation in normal and reduced diastolic function

    OpenAIRE

    Skjaerpe Terje; Skjelvan Gunnar; Støylen Asbjørn

    2003-01-01

    Abstract Background Strain Rate Imaging shows the filling phases of the left ventricle to consist of a wave of myocardial stretching, propagating from base to apex. The propagation velocity of the strain rate wave is reduced in delayed relaxation. This study examined the relation between the propagation velocity of strain rate in the myocardium and the propagation velocity of flow during early filling. Methods 12 normal subjects and 13 patients with treated hypertension and normal systolic fu...

  17. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

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

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...

  18. Thrombus aspiration in acute myocardial infarction.

    Science.gov (United States)

    Mahmoud, Karim D; Zijlstra, Felix

    2016-07-01

    The success of primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is often hampered by incomplete microvascular myocardial reperfusion owing to distal embolization of thrombus resulting in microvascular obstruction. To address this problem, thrombus aspiration devices have been developed that can be used to evacuate coronary thrombus either manually or mechanically. Thrombus aspiration has the potential to reduce the local thrombus load, minimize the need for balloon predilatation, facilitate direct stenting, prevent distal embolization, and ultimately improve myocardial reperfusion. Furthermore, thrombus aspiration has enabled us to study coronary thrombus in vivo, and has facilitated recognition of distinct mechanisms of coronary thrombosis. Clinical trials focusing on manual thrombus aspiration in primary PCI have generally shown improved myocardial reperfusion. However, in two large trials powered for clinical end points, no reduction in 1-year mortality or other adverse clinical events was observed with the use of this strategy. Moreover, one of these trials showed a marginally increased risk of stroke. Consequently, current guidelines do not recommend routine use of thrombus aspiration. Future studies should focus on the identification of subgroups of patients with STEMI who might derive benefit from manual thrombus aspiration, and establish the effect of operator performance on the efficacy and safety of the procedure. PMID:26961064

  19. Myocardial protection: what the anesthesiologist does.

    Science.gov (United States)

    Merin, R G

    1990-09-01

    The role of the anesthesiologist in myocardial protection is to optimize myocardial oxygen balance during the perioperative period. Nonpharmacological steps that can be taken to achieve this revolve around maintaining a satisfactory hemoglobin concentration and oxyhemoglobin saturation through maximizing ventilation. In addition, alkalosis and hypothermia should be prevented since they cause a left shift of the oxyhemoglobin dissociation curve, thus interfering with tissue oxygen delivery. Hypocarbia increases coronary vascular resistance. Blood volume must be adequate with an optimal hemoglobin concentration. Pharmacological measures should also be used, and it is important to continue through the perioperative period any previously administered cardioactive drugs. Furthermore, in the prebypass period, tachycardia may not be controlled by anesthetics; unless the tachycardia is paroxysmal, beta blockers are the drugs of choice. Depending on the cause, diastolic hypotension also needs to be treated either with volume, vasoconstrictors, or inotropes. Likewise, major hypertension can produce increased demand and, again depending on the cause, either anesthetics, vasodilators, beta blockers, or calcium blockers may be useful. Finally, myocardial ischemia without obvious cause probably should be treated with nitroglycerin or calcium blockers. During surgery, the effect of the anesthetic drugs on myocardial oxygen balance is important. PMID:2133851

  20. Management of myocardial damage in muscular dystrophy

    International Nuclear Information System (INIS)

    Heart failure (HF) is a fatal complication in many muscular dystrophy cases and has become the most common cause of death in Duchenne muscular dystrophy (DMD) since 2001. HF deaths in DMD occur in young patients and increase, along with respiratory failure, in older patients. Managing HF, therefore, is the most important component of DMD treatment. Management of HF is necessary in DMD patients of all ages because myocardial damage progresses regardless of age and disability. Electrocardiography, echocardiography, myocardial single-photon emission computed tomography (SPECT), and natriuretic peptides are used for the diagnosis of myocardial damage and chronic HF. Tissue Doppler echocardiography is in particularly useful for early detection of minute myocardial damage and dysfunction in DMD. The first-line drugs for chronic HF are angiotensin-converting enzyme inhibitors, and the prognosis of DMD patients has been improved using these drugs and beta-blockers. Diuretics are added in the presence of pulmonary congestion. Digoxin is most effective at a blood level of 0.5-0.8 ng/mL because of its pharmacokinetics in DMD. Surgical treatment may be necessary in cases of intractable HF. Cardiac resynchronization therapy (biventricular pacing), a treatment with an artificial pacemaker, is indicated for cases that meet specific criteria, including HF with ventricular dyssynchrony. Applications of partial left ventriculectomy (Batista procedure) and left ventricular assist devices in muscular dystrophy are likely in the near future. (author)

  1. Primary coronary angioplasty in acute myocardial infarction.

    OpenAIRE

    Grech, E. D.; Ramsdale, D. R.

    1996-01-01

    It is well established that recanalisation of the infarct-related artery is of great benefit in the early hours after acute myocardial infarction. This can be achieved by the use of thrombolytic agents and/or by percutaneous transluminal coronary angioplasty (PTCA). This article reviews data on the role of primary PTCA and summarises current opinion on its use.

  2. THROMBOLYTIC THERAPY OF ACUTE MYOCARDIAL INFARCTION

    OpenAIRE

    D. P. Sementsov

    2015-01-01

    Importance of thrombolytic therapy for restoration of coronary blood flow in acute myocardial infarction is emphasized. Indications and contraindications, advantages and disadvantages for thrombolysis therapy are discussed. The ways of different thrombolytics implementation, efficacy criteria and possible side effects are also presented.

  3. TOWARD THE QUESTION OF ISCHEMIC MYOCARDIAL DYSFUNCTION

    Directory of Open Access Journals (Sweden)

    V. V. Kalyuzhin

    2015-12-01

    Full Text Available The authors of the review have analyzed papers published on the problem of ischemic myocardial dysfunction. They begin with a definition of the term “ischemia” (derived from two Greek words: ischō, meaning to hold back, and haima, meaning blood - a condition at which the arterial blood flow is insufficient to provide enough oxygen to prevent intracellular respiration from shifting from the aerobic to the anaerobic form. The poor rate of ATP generation from this process causes a decrease in cellular ATP, a concomitant rise in ADP, and ultimately, to depression inotropic (systolic and lusitropic (diastolic function of the affected segments of the myocardium. But with such simplicity of basic concepts, the consequences of ischemia so diverse. Influence of an ischemia on myocardial function so unequally at different patients, which is almost impossible to find two identical cases (as in the case of fingerprints. It depends on the infinite variety of lesions of coronary arteries, reperfusion (time and completeness of restoration of blood flow and reactions of a myocardium which, apparently, has considerable flexibility in its response. Ischemic myocardial dysfunction includes a number of discrete states, such as acute left ventricular failure in angina, acute myocardial infarction, ischemic cardiomyopathy, stunning, hibernation, pre- and postconditioning. There are widely differing underlying pathophysiologic states. The possibility exists that several of these states can coexist.

  4. Pseudoxanthoma elasticum presenting with myocardial infarction.

    OpenAIRE

    Slade, A K; John, R.M.; Swanton, R H

    1990-01-01

    A 31 year old man presented with an anterior myocardial infarction. He had a history of recurrent gastrointestinal bleeding of obscure cause since childhood and peripheral vascular disease. A clinical diagnosis of the type 1 dominant form of pseudoxanthoma elasticum was supported by histological data from skin biopsy.

  5. MYOCARDIAL REMODELING IN ISCHEMIC HEART DISEASE

    Directory of Open Access Journals (Sweden)

    A. N. Zakirova

    2016-01-01

    Full Text Available Aim. To study the myocardial remodeling features in patients with stable angina depending on disease severity and experienced myocardial infarction (MI.Material and methods. 148 male patients with stable angina were examined and randomized into 3 groups (G1-G3. 52 patients of G1 had angina of I-II functional class (FC. 49 patients of G2 had angina of III FC, and 47 patients of G3 had angina of IV FC. History of MI had 79,5, 87.2 and 92.6% of patients in G1, G2 and G3 respectively. 35 healthy men were included into control group. Coronarography, bicycle ergometry and 24-hour ECG monitoring was performed. Left ventricular (LV function and remodeling was assessed with echocardiography.Results. G3 patients had LV eccentric hypertrophy as a result of postinfarction cardiosclerosis which accompanied with LV systolic dysfunction, a myocardial stress increasing and LV spherification. G1 patients had no any significant disorders of LV systolic function.Conclusion. Severe ischemic heart disease is associated with a dysadaptive remodeling unlike mild ischemic heart disease, which is associated with an adaptive myocardial remodeling.

  6. THROMBOLYTIC THERAPY OF ACUTE MYOCARDIAL INFARCTION

    Directory of Open Access Journals (Sweden)

    D. P. Sementsov

    2015-12-01

    Full Text Available Importance of thrombolytic therapy for restoration of coronary blood flow in acute myocardial infarction is emphasized. Indications and contraindications, advantages and disadvantages for thrombolysis therapy are discussed. The ways of different thrombolytics implementation, efficacy criteria and possible side effects are also presented.

  7. Thrombolytic therapy in acute myocardial infarction.

    Science.gov (United States)

    Woo, K S; White, H D

    1994-07-01

    Thrombolytic therapy has revolutionized the treatment of acute myocardial infarction by reducing mortality and preserving left ventricular function. It is relatively safe and cost-effective. However, it is currently underused in most countries. Patients in whom thrombolysis is indicated include those with ST elevation on the electrocardiogram or bundle branch block pattern who present within 12 hours of myocardial infarction; the indications should be widened to include the elderly, patients who have undergone nontraumatic cardiopulmonary resuscitation, and women during menstruation. The risk-benefit ratio should be assessed for the individual patient. Prehospital thrombolytic treatment has been shown to be feasible with the support of well-trained staff and resuscitation equipment, and may be cost-effective in communities with time delays before hospitalization greater than 1 hour. The most important strategy is to shorten the "door to needle" time in hospital. The importance of full infarct-related artery flow (Thrombolysis in Myocardial Infarction [TIMI] grade 3 flow) for preservation of ventricular function and survival has been documented in the second Thrombolysis Trial of Eminase in Acute Myocardial Infarction (TEAM 2) and the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) studies. Aspirin and heparin are beneficial adjunctive regimens to thrombolytic therapy but optimal epicardial reperfusion is achieved in only about half of patients. Improved thrombolytic, adjunctive antiplatelet, and antithrombotic regimens are required to achieve early full reperfusion, which is crucial to improve survival and quality of life. PMID:7919592

  8. Stochastic precision analysis of 2D cardiac strain estimation in vivo

    International Nuclear Information System (INIS)

    Ultrasonic strain imaging has been applied to echocardiography and carries great potential to be used as a tool in the clinical setting. Two-dimensional (2D) strain estimation may be useful when studying the heart due to the complex, 3D deformation of the cardiac tissue. Increasing the framerate used for motion estimation, i.e. motion estimation rate (MER), has been shown to improve the precision of the strain estimation, although maintaining the spatial resolution necessary to view the entire heart structure in a single heartbeat remains challenging at high MERs. Two previously developed methods, the temporally unequispaced acquisition sequence (TUAS) and the diverging beam sequence (DBS), have been used in the past to successfully estimate in vivo axial strain at high MERs without compromising spatial resolution. In this study, a stochastic assessment of 2D strain estimation precision is performed in vivo for both sequences at varying MERs (65, 272, 544, 815 Hz for TUAS; 250, 500, 1000, 2000 Hz for DBS). 2D incremental strains were estimated during left ventricular contraction in five healthy volunteers using a normalized cross-correlation function and a least-squares strain estimator. Both sequences were shown capable of estimating 2D incremental strains in vivo. The conditional expected value of the elastographic signal-to-noise ratio (E(SNRe|ε)) was used to compare strain estimation precision of both sequences at multiple MERs over a wide range of clinical strain values. The results here indicate that axial strain estimation precision is much more dependent on MER than lateral strain estimation, while lateral estimation is more affected by strain magnitude. MER should be increased at least above 544 Hz to avoid suboptimal axial strain estimation. Radial and circumferential strain estimations were influenced by the axial and lateral strain in different ways. Furthermore, the TUAS and DBS were found to be of comparable precision at similar MERs. (paper)

  9. [Prehospital thrombolytic therapy in acute myocardial infarction].

    Science.gov (United States)

    Carlsson, J; Schuster, H P; Tebbe, U

    1997-10-01

    The extent of myocardial damage occurring during acute myocardial infarction is time dependent, and there is abundant evidence from most clinical trials that mortality reduction is greatest in patients treated early with thrombolytic agents, although beneficial effects have been shown with treatment initiated up to 12 h after onset of symptoms. All studies on prehospital thrombolysis have conclusively shown the practicability and safety of patient selection and administration of the thrombolytic agent. The accuracy of diagnosis in the prehospital setting was comparable to trials of in-hospital thrombolysis, e.g., in the Myocardial Infarction Triage and Intervention Project (MITI) 98% of the patients enrolled had subsequent evidence of acute myocardial infarction. With regard to time savings, all randomized studies showed positive results. The smallest time gain was observed in the MITI trial: prehospital-treated patients received thrombolytic therapy an average of 33 min earlier than those treated in hospital. In the European Myocardial Infarction Project (EMIP) the difference in time between prehospital and hospital treatment was a median of 55 min. However, none of these trials was able to show a significant short-term mortality difference between the two groups. Only a meta analysis of five randomized studies with a combined median time gain of about 60 min showed a significant 17% reduction in short-term mortality for patients who received thrombolytic therapy in the prehospital phase. In the Grampian Region Early Anistreplase Trial (GREAT), a study performed in a more rural area than other studies, the time gain by prehospital initiation of thrombolysis was a median of 130 min. GREAT was the only study to date reporting a significant mortality benefit for prehospital-treated patients after 3 months and 1 year. In conclusion, prehospital thrombolysis is feasible and safe. Patients with acute myocardial infarction can be correctly identified and treated with

  10. 铝合金桁架环缝自动焊机的研制%Design and manufacture of automatic circumferential welding equipment for aluminium alloy boom

    Institute of Scientific and Technical Information of China (English)

    田松亚; 封艳

    2012-01-01

    根据铝合金桁架铝合金管材与接头环缝焊接要求,设计并制造了一台专用焊接设备.根据焊接时序要求,采用可编程控制器实现对焊接设备逻辑顺序的控制,并制定了铝合金桁架铝合金管材与接头环缝的惰性气体保护焊MIG自动焊接工艺.结果表明,该焊机自动化程度高、性能稳定、操作简便,能够满足铝桁架铝合金管材与接头环缝自动焊生产要求,同时提高了生产率.依据制定的焊接工艺,进行了焊接试验.焊接试验表明,制定的工艺所获得的铝合金桁架铝合全管材与接头对接接头,满足焊缝质量要求.%According to the requirements of aluminium alloy boom circumferential welding,this paper design and manufacture a special automatic welding equipment.In terms of weld time sequence requirement,PLC is used to implement the control of welding device logical subsequence.besides.work out the MIG automatic welding procedure of circumferential welding.The Result shows that the welding device displays high degree of automation,stable performance and convenient movement,which could satisfy production requirements of aluminium alloy boom automatic circumferential welding and improve productivity .Based on the welding procedure, welding experiment is done.The result indicates that welding procedure could reach the quality requirements of welding joint.

  11. Detection of myocardial infarction with dual energy CT myocardial iodine maps and perfusion myocardial single photon emission computed tomography scintigraphy: an experimental study in canine

    International Nuclear Information System (INIS)

    Objective: To investigate the feasibility and accuracy of dual energy CT myocardial iodine maps in detecting acute myocardial infarction in canine model. Methods: Myocardial ischemia model was made by ligaturing left anterior descending coronary arteries (LAD) after thoracotomy in six dogs, while another 3 dogs undergoing thoracotomy not ligaturing LAD as control group. Before and three hours after operation, dual-source CT (DSCT) was performed, followed by resting 99Tcm-MIBI single photon emission computed tomography myocardial perfusion imaging. Then, dogs were sacrificed, and the hearts were removed, triphenyketrazolium chloride staining and conventional HE staining were performed. CT number of non-ischemic and ischemic regions were measured and analyzed. The wall of the left ventricle in the short axis was divided into 17 segments, the segments of myocardial perfusion defect in DSCT myocardial iodine maps, SPECT, and pathology were determined. Student t test was used to analyze the difference of CT number between infarcted and non-infarcted myocardium. Kappa test was used for the accuracy of DSCT myocardial iodine maps and SPECT in detecting myocardial ischemia according to the pathological results. Results: No abnormal regions were detected using DSCT myocardial iodine maps in preoperative control and infarction group. After thoracotomy, partial sparse or defective perfusion was consistently noted in six dogs' apical anterior and partition wall in both DSCT myocardial iodine maps and SPECT. In the infarcted group, the attenuation of infarction region (34.75±16.66) HU was significantly decreased compared with preoperative measurements (123.18±15.38 ) HU (t=10.526, P<0.01); decreased perfusion in the infarcted region was also noted in the DSCT myocardial iodine maps and SPECT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT myocardial iodine maps and SPECT were 85.0% (34/40), 84.1% (95/113), 65.4% (34

  12. Mis-Match Limit Load Analyses and Fracture Mechanics Assessment for Welded Pipe with Circumferential Crack at the Center of Weldment

    International Nuclear Information System (INIS)

    In this paper, limit load analyses and fracture mechanics analyses were conducted via finite element analyses for the welded pipe with circumferential crack at the center of the weldment. Systematic changes for strength mismatch ratio, width of weldment, crack shape and thickness ratio of the pipe were considered to provide strength mismatch limit load. And J-integral calculations based on reference stress method were conducted for two materials, stainless steel and ferritic steel. Reference stress defined by provided strength mis-match limit load gives much more accurate J-integral

  13. The effect of deformation on unloading compliance values of TPB specimens and throughwall circumferentially cracked straight pipes under four point bending load

    International Nuclear Information System (INIS)

    Compliance technique is one of the convenient methods to measure crack growth during fracture experiments. One correlation expressing crack size as a function of unloading compliance is the prerequisite of this technique. Conventionally, compliance correlation is derived by generating compliance VI crack length data by performing small displacement linear elastic finite element analysis. However, it does not account for the large geometric deformation that may take place during the loading of the specimen. The unloading compliance may be influenced by the increasing stiffness of the specimen because of change In basic geometry. It is, therefore, of interest to study the effect of deformation on the unloading compliance. In the present work, elastic-plastic finite element analysis is carried out on three point bend (TPB) specimens and throughwall circumferentially cracked pipes under four point bending load. In case of TPB specimens, unloading compliance correlation is available. However, this correlation does not consider the effect of deformation on the compliance. The objective of this study is, therefore to investigate whether deformation of the TPB specimen changes the unloading compliances or not and whether this change, if any, warrants any modifications in the existing compliance correlation. In case of throughwall circumferentially cracked straight pipe under four point bending load which is a common component for fracture studies, no such compliance correlation is available. Because of ovalisation of pipe cross section during deformation, compliance not only depends on current crack length, but also on current load. In the present work, elastic-plastic finite element analysis has been carried out on pipes having various diameter, thickness and circumferential throughwall crack sizes. The objective is to study how initial elastic compliance of pipe is affected by deformation of the original circular cross section. From the foregoing analyses, two

  14. Clinical use of 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    Myocardial imaging with 201Tl and scinticamera was studied experimentally using specially designed phantoms and clinically in 23 patients with myocardial infarction or other heart disease. In the phantom experiment, quality of image, accumulative count rate, and detectability of the defect were compared to obtain the best technique for their detection, using four different collimators, i.e., converging, pin-hole, 4000-hole, and 140 keV high-resolution, at two photopeak levels of 201Tl of 75 and 167 keV, and combining a radiation absorber. In patient examination, myocardial images taken at different periods after injection, different detecting conditions of the scinticamera, and various detecting projections were compared. Images of the converging collimator at the 75 keV photopeak revealed considerably higher accumulative counts and relatively higher quality than those of other detecting conditions. It was necessary to take as many images as possible in various projections, in order to detect the location and size of the myocardial ischemic lesion because the lesion was demonstrated as a clear defect only in profile. It became evident that images taken between about 25 and 90 min delineated the myocardium more clearly than those taken in other periods. Normal images taken in 8 patients without ischemic heart disease appeared in the shape of a doughnut of horseshoe, demonstrating mainly the left venticular myocardium. The image was faint in the region of the aortic or mitral valve and thin in the region of the apical wall. A faint image of the right ventricular myocardium was sometimes seen. In 3 patients with valvular heart disease, findings suggested changes in the thickness of myocardium and the distribution of coronary blood flow. In 11 of 12 patients with old myocardial infarction, the location and size of the lesion was detected. (Evans, J.)

  15. Strain Distribution in Root Surface Dentin of Maxillary Central Incisors during Lateral Compaction.

    Directory of Open Access Journals (Sweden)

    Raphael Pilo

    Full Text Available To precisely quantify the circumferential strains created along the radicular dentin of maxillary incisors during a simulated clinical procedure of lateral compaction.Six miniature strain gauges were bonded on the roots of fourteen recently extracted maxillary central incisors that were subjected to root canal instrumentation. The strain gauges were bonded at three levels (apical, middle, and coronal and four aspects (buccal, lingual, mesial, and distal of the roots. Each tooth was embedded in a PVC cylinder containing polyvinyl-siloxane impression material. Root filling was then performed by simulating the clinical procedure of lateral compaction using nickel-titanium finger spreaders. The force applied to the spreader and the strains developing in the surface root dentin were continuously recorded at a frequency of 10 Hz.The highest strains that developed during lateral compaction were in the mesial and distal aspects at the apical level of the root. The magnitudes of the maximal mesial/distal strains at the apical as well as the mid-root levels were approximately 2.5-3 times higher than those at the buccal/lingual aspects (p = 0.041. The strains decreased significantly (p<0.04 from the apical through the mid-root levels to the coronal level, yielding gradients of 2.5- and 6-fold, respectively. The mesial and distal strains were consistently tensile and did not differ significantly; however, the buccal strains were generally 35-65% higher than the lingual strains (p = 0.078. Lateral compaction resulted in the gradual build-up of residual strains, resulting in generation of a 'stair-step' curve. These strains declined gradually and almost completely disappeared after 1000 sec.With proper mounting of several miniature strain gauges at various levels and aspects of the root, significant circumferential strains can be monitored under clinically relevant compaction forces. The residual strains at the end of lateral compaction are not stored in the

  16. Risk prediction of ventricular arrhythmias and myocardial function in Lamin A/C mutation positive subjects

    DEFF Research Database (Denmark)

    Hasselberg, Nina E; Edvardsen, Thor; Petri, Helle;

    2014-01-01

    /C mutation-positive subjects. PR-interval and occurrence of VA were recorded. Left ventricular (LV) myocardial function was assessed as ejection fraction and speckle tracking longitudinal strain by echocardiography. Magnetic resonance imaging was performed to assess fibrosis in a selection of subjects......Mutations in the Lamin A/C gene may cause atrioventricular block, supraventricular arrhythmias, ventricular arrhythmias (VA), and dilated cardiomyopathy. We aimed to explore the predictors and the mechanisms of VA in Lamin A/C mutation-positive subjects.METHODS AND RESULTS: We included 41 Lamin A...

  17. Effect of myocardial ischemia and nitroglycerin on systolic time intervals in the segmental myocardium

    Directory of Open Access Journals (Sweden)

    Haraoka,Shoichi

    1978-04-01

    Full Text Available Effects of ischemia and nitroglycerin on systolic time intervals in the segmental myocardial length were studied in anesthetized open-chest dogs. Two strain-gauges were sutured on the surface of the left ventricular wall; one was in the central area perfused by the left circumflex coronary artery (LCX and the other was in the area perfused by the left anterior descending coronary artery. LCX was partially occluded with a screw type constrictor to the degree at which reactive hyperemia after the transient total coronary occlusion almost disappeared. After the hemodynamics stabilized nitroglycerin (20 microgram/kg was injected into the femoral vein. In the ischemic area, contraction time was shortened and precontraction time was prolonged in association with an elongation of end-systolic and early systolic segment-length, respectively. The systolic time intervals in the ischemic segment were improved as a result of the recovery in the segment-length toward the control. The results suggest the usefulness of analyzing the segmental myocardial systolic time intervals for verifying the asynchronous contraction of the ventricle and the favourable effects of nitroglycerin on segmental myocardial function in the ischemic area.

  18. Strain Imaging: The Emergence of Speckle Tracking Echocardiography into Clinical Pediatric Cardiology.

    Science.gov (United States)

    Colquitt, John L; Pignatelli, Ricardo H

    2016-01-01

    Speckle tracking echocardiography measures myocardial strain and allows for the quantification of regional and global left and right ventricular function. A growing body of literature is supporting its transition from research into clinical practice. This article aims to provide a practical review of strain imaging as it applies to congenital and pediatric heart disease, with the goals of increasing literacy and advocating for greater clinical integration. PMID:26879728

  19. Oligophrenin1 protects mice against myocardial ischemia and reperfusion injury by modulating inflammation and myocardial apoptosis.

    Science.gov (United States)

    Niermann, Christina; Gorressen, Simone; Klier, Meike; Gowert, Nina S; Billuart, Pierre; Kelm, Malte; Merx, Marc W; Elvers, Margitta

    2016-08-01

    The Rho family of small GTPases has been analyzed in cardiac physiology and pathophysiology including myocardial infarction (MI) in the last years. Contradictory results show either a protective or a declined effect of RhoA and the RhoA effector Rho-associated protein kinase (ROCK) in myocardial ischemia and reperfusion injury that is associated with cardiomyocyte survival and caspase-3 activation. Cardiac-specific deletion of Rac1 reduced ischemia reperfusion injury in diabetic hearts, whereas cardiomyocyte specific overexpression of active Rac1 predisposes the heart to increased myocardial injury with enhanced contractile dysfunction. GTPase-activating proteins (GAPs) control the activation of Rho proteins through stimulation of GTP hydrolysis. However, the impact of GAPs in myocardial ischemia and reperfusion injury remains elusive. Here we analyzed the role of oligophrenin1 (OPHN1), a RhoGAP with Bin/Amphiphysin/Rvs (BAR) domain known to regulate the activity of RhoA, Rac1 and Cdc42 in MI. The expression of Ophn1, RhoA and Rac1 is strongly upregulated 24h after myocardial ischemia. Loss of OPHN1 induced enhanced activity of Rho effector molecules leading to elevated cardiomyocyte apoptosis and increased migration of inflammatory cells into the infarct border zone of OPHN1 deficient mice. Consequently, echocardiography 24h after myocardial ischemia revealed declined left ventricle function in OPHN1 deficient mice. Our results indicate that OPHN1 mediated regulation of RhoA, Rac1 and Cdc42 is crucial for the preservation of cardiac function after myocardial injury. PMID:27117132

  20. Early myocardial dysfunction in streptozotocin-induced diabetic mice: a study using in vivo magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Chandrasekaran Suresh

    2007-02-01

    Full Text Available Abstract Background Diabetes is associated with a cardiomyopathy that is independent of coronary artery disease or hypertension. In the present study we used in vivo magnetic resonance imaging (MRI and echocardiographic techniques to examine and characterize early changes in myocardial function in a mouse model of type 1 diabetes. Methods Diabetes was induced in 8-week old C57BL/6 mice with two intraperitoneal injections of streptozotocin. The blood glucose levels were maintained at 19–25 mmol/l using intermittent low dosages of long acting insulin glargine. MRI and echocardiography were performed at 4 weeks of diabetes (age of 12 weeks in diabetic mice and age-matched controls. Results After 4 weeks of hyperglycemia one marker of mitochondrial function, NADH oxidase activity, was decreased to 50% of control animals. MRI studies of diabetic mice at 4 weeks demonstrated significant deficits in myocardial morphology and functionality including: a decreased left ventricular (LV wall thickness, an increased LV end-systolic diameter and volume, a diminished LV ejection fraction and cardiac output, a decreased LV circumferential shortening, and decreased LV peak ejection and filling rates. M-mode echocardiographic and Doppler flow studies of diabetic mice at 4 weeks showed a decreased wall thickening and increased E/A ratio, supporting both systolic and diastolic dysfunction. Conclusion Our study demonstrates that MRI interrogation can identify the onset of diabetic cardiomyopathy in mice with its impaired functional capacity and altered morphology. The MRI technique will lend itself to repetitive study of early changes in cardiac function in small animal models of diabetic cardiomyopathy.

  1. Longitudinal strain from velocity encoded cardiovascular magnetic resonance: a validation study

    Directory of Open Access Journals (Sweden)

    Heiberg Einar

    2013-01-01

    Full Text Available Abstract Background Regional myocardial function is typically evaluated by visual assessment by experienced users, or by methods requiring substantial post processing time. Visual assessment is subjective and not quantitative. Therefore, the purpose of this study is to develop and validate a simple method to derive quantitative measures of regional wall function from velocity encoded Cardiovascular Magnetic Resonance (CMR, and provide associated normal values for longitudinal strain. Method Both fast field echo (FFE and turbo field echo (TFE velocity encoded CMR images were acquired in three long axis planes in 36 healthy volunteers (13 women, 23 men, age 35±12 years. Strain was also quantified in 10 patients within one week after myocardial infarction. The user manually delineated myocardium in one time frame and strain was calculated as the myocardium was tracked throughout the cardiac cycle using an optimization formulation and mechanical a priori assumptions. A phantom experiment was performed to validate the method with optical tracking of deformation as an independent gold standard. Results There was an excellent agreement between longitudinal strain measured by optical tracking and longitudinal strain measured with TFE velocity encoding. Difference between the two methods was 0.0025 ± 0.085 (ns. Mean global longitudinal strain in the 36 healthy volunteers was −0.18 ± 0.10 (TFE imaging. Intra-observer variability for all segments was 0.00 ± 0.06. Inter-observer variability was −0.02 ± 0.07 (TFE imaging. The intra-observer variability for radial strain was high limiting the applicability of radial strain. Mean longitudinal strain in patients was significantly lower (−0.15± 0.12 compared to healthy volunteers (p Conclusion In conclusion, we have developed and validated a robust and clinically applicable technique that can quantify longitudinal strain and regional myocardial wall function and present the associated normal values

  2. Cerebral hemodynamic difference between early- and late-onset Alzheimer's disease by circumferential profile analysis with 123I-IMP brain SPECT

    International Nuclear Information System (INIS)

    We conducted investigation to determine whether early- and late-onset Alzheimer's diseases differ pathophysiologically. Five patients with the early-onset (65 years and under) of the disease and 11 with the late-onset (65 years and over) of the disease were studied by single photon emission CT (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP). Circumferential profile analysis (CPA) was performed to examine differences in the predominant hypoperfusion in the temporoparietal lobe, which is considered to be functionally damaged the most in Alzheimer's disease. The Xm values, calculated from gradients between the motorsensory or occipital cortices and temporoparietal cortex in the circumferential profile curve, were compared in both groups. The Xm values for patients with early- and late-onset Alzheimer's disease were 6.81±2.10 (counts/degree) and 3.28±1.58, respectively, the difference being significant. Our results suggest that functional abnormalities in the temporoparietal area severer in early- than late-onset Alzheimer's disease and that the application of CPA to IMP SPECT is useful to elucidate the pathophysiological difference between each of the disease. (author)

  3. Altered myocardial substrate metabolism is associated with myocardial dysfunction in early diabetic cardiomyopathy in rats: studies using positron emission tomography

    Directory of Open Access Journals (Sweden)

    Lammertsma Adriaan A

    2009-07-01

    Full Text Available Abstract Background In vitro data suggest that changes in myocardial substrate metabolism may contribute to impaired myocardial function in diabetic cardiomyopathy (DCM. The purpose of the present study was to study in a rat model of early DCM, in vivo changes in myocardial substrate metabolism and their association with myocardial function. Methods Zucker diabetic fatty (ZDF and Zucker lean (ZL rats underwent echocardiography followed by [11C]palmitate positron emission tomography (PET under fasting, and [18F]-2-fluoro-2-deoxy-D-glucose PET under hyperinsulinaemic euglycaemic clamp conditions. Isolated cardiomyocytes were used to determine isometric force development. Results PET data showed a 66% decrease in insulin-mediated myocardial glucose utilisation and a 41% increase in fatty acid (FA oxidation in ZDF vs. ZL rats (both p glucose transporter-4 mRNA expression (p Conclusion Using PET and echocardiography, we found increases in myocardial FA oxidation with a concomitant decrease of insulin-mediated myocardial glucose utilisation in early DCM. In addition, the latter was associated with impaired myocardial function. These in vivo data expand previous in vitro findings showing that early alterations in myocardial substrate metabolism contribute to myocardial dysfunction.

  4. Evaluation of myocardial abnormalities in collagen diseases by thallium-201 myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Yamano, Shigeru; Kagoshima, Tadashi; Sugihara, Kiyotaka (Nara Medical Univ., Kashihara (Japan)) (and others)

    1993-12-01

    This study was performed to evaluate myocardial abnormalities in patients with collagen diseases by exercise and rest thallium-201 myocardial scintigrams. A total of 65 patients without ischemic ECG changes, consisting of 18 with systemic lupus erythematosus (SLE), 18 with polymyositis (PM), 8 with progressive systemic sclerosis (PSS), and 21 with Sjoegren's syndrome (SjS), was enrolled in this study. Reversible exercise-induced defects scintigraphically suggesting myocardial ischemia were noted in 8 cases of SLE, 4 cases of PM, 4 cases of PSS, and 3 cases of SjS. Nineteen patients had exercise-induced defects and underwent cardiac catheterization, 8 of whom had normal coronary angiograms. Fixed hypoperfusion areas were observed in one case of SLE, 6 cases of PM and 3 cases of SjS. Rest thallium-201 myocardial scintigram disclosed hypoperfusion areas which were not induced by exercise in 2 cases of SLE, 3 cases of PM, one case of PSS and 5 cases of SjS. Echocardiogram showed no significant differences in ejection fraction and % fractional shortening between the disease groups and healthy control group. These findings suggest that patients with collagen diseases have abnormalities of coronary circulation at the level of the intramural vasculature before cardiac function impairment, myocardial fibrosis and functional abnormalities at the cell membrane. (author).

  5. Use of resting myocardial scintigraphy during chest pain to exclude diagnosis of acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Barbirato, Gustavo Borges; Azevedo, Jader Cunha de; Felix, Renata Christian Martins; Correa, Patricia Lavatori; Volschan, Andre; Viegas, Monica; Pimenta, Lucia; Dohmann, Hans Fernando Rocha; Mesquita, Evandro Tinoco; Mesquita, Claudio Tinoco [Centro de Estudos do Hospital Pro-Cardiaco (Procep), Rio de Janeiro, RJ (Brazil)

    2009-04-15

    Background: Images of myocardial perfusion taken during an episode of chest pain have been used for patients in the emergency department. Objective: To evaluate the operating characteristics of {sup 99m}Tc-Tetrofosmin scintigraphy during an episode of chest pain to exclude the diagnosis of cute myocardial infarction. Methods: One hundred and eight patients admitted with chest pain, or up to four hours after the end of symptoms and non diagnostic electrocardiogram, underwent resting scintigraphy and measurement of troponin I concentrations. Patients with a history of myocardial infarction (MI) were not excluded (24 patients). Troponin I concentrations were determined at admission and 6 hours later. Nuclear physicians performed a blind analysis of the images, and myocardial infarction was confirmed whenever troponin I level increase was three times that of the control. Results: Resting perfusion image was abnormal in all 6 patients with MI. Only 1 patient had a normal image and increased troponin levels. Fifty-five patients had positive images without MI, and 46 patients had normal images and troponin levels. The prevalence of the disease was 6.5%. The sensitivity and specificity of the resting images during an episode of chest pain to diagnose MI was 85.7% and 45.5%, respectively. The negative predictive value was 97.7%. Conclusion: Patients undergoing chest pain protocol with SPECT showed an excellent negative predictive value to exclude diagnosis of myocardial infarction. These results suggest that resting perfusion image is an important tool at the chest pain unit. (author)

  6. Evaluation of myocardial damage in Duchenne's muscular dystrophy with thallium-201 myocardial SPECT

    International Nuclear Information System (INIS)

    Myocardial damage and cardiopulmonary functions in patients with Duchenne's muscular dystrophy (DMD) were assessed using thallium-201 myocardial single-photon emission computed tomography (SPECT) and technetium-99m multigated radionuclide angiography. Twenty-five patients with DMD were divided into 4 groups according to percent of perfusion defect (%PD) calculated by the bull's-eye method and age. PD was detected in 24 (96.0%) of 25 patients with DMD, and it spread from the left ventricular lateral wall to the anterior wall and/or interventricular septum. PD was detected even in a 6-year-old DMD boy. Patients in Group I (%PD≥10% and age<15 years old) were shown to have a higher risk of left-sided heart failure without respiratory failure. Patients in Group II (%PD≥10 and age≥15) showed decreased pulmonary function and worsened arterial blood gas values as compared with Group IV (%PD<10 and age≥15). There was no significant difference in cardiac function among the 4 groups. It is postulated that myocardial damage in Group II patients is dependent primarily on a deficiency of dystrophin and on chronic respiratory failure, and that some of them are at risk of cardiopulmonary failure. It is concluded that myocardial SPECT is useful for the early diagnosis of myocardial damage and evaluation of cardiopulmonary function in DMD patients. (author)

  7. ST segment elevation after myocardial infarction: Viability or ventricular dysfunction? Comparison with myocardial scintigraphy

    International Nuclear Information System (INIS)

    The detection of viable myocardium after myocardial infarction is an important indication for revascularization. We compared exercise-induced ST segment elevation with reversibility at Thallium-201 SPECT scintigraphy and regional wall motion assessment by ventriculography. Thirty two patients with previous myocardial infarction and with left ventricular ejection fraction of < 50% were studied. Patients underwent coronary angiography and Thallium-201 SPECT scintigraphy with re-injection protocol before and after coronary artery bypass graft surgery. Group I comprised 11 patients with ST segment elevation during treadmill stress testing. Group II comprised 21 patients without ST segment elevation. Minimal or moderate hypokinesis was present in 2 patients of Group I and in 4 patients of Group II. Nine patients of Group I and 17 patients of Group II had severe hypokinetic, akinetic or dyskinetic myocardium. Scintigraphy revealed reversibility in the myocardial infarction area in 4 patients from Group I (36.4%) and 11 (52.4%) patients from Group II. Improvement in perfusion after coronary artery bypass grafting was observed in 4 patients from Group I and 8 patients from Group II. Sensitivity, specificity, accuracy, and positive and negative predictive values of ST segment elevation were 33.3, 70.6, 55.2, 44.5 and 60% respectively. It was concluded that exercise-induced ST segment elevation after myocardial infarction is present more frequently in cases of severe regional myocardial dysfunction. (author)

  8. Effect of Wenxin Granule on Ventricular Remodeling and Myocardial Apoptosis in Rats with Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Aiming Wu

    2013-01-01

    Full Text Available Aim. To determine the effect of a Chinese herbal compound named Wenxin Granule on ventricular remodeling and myocardial apoptosis in rats with myocardial infarction (MI. Methods. Male Sprague-Dawley (SD rats were randomly divided into four groups: the control group, the model group, the metoprolol group, and the Wenxin Granule group (WXKL group with sample size (n of 7 rats in each group. An MI model was established in all rats by occlusion of the left anterior descending coronary artery (the control group was without occlusion. Wenxin Granule (1.35 g/kg/day, metoprolol (12 mg/kg/day, and distilled water (5 mL/kg/day for the control and model groups were administered orally for 4 weeks. Ultrasonic echocardiography was used to examine cardiac structural and functional parameters. Myocardial histopathological changes were observed using haematoxylin and eosin (H&E dyeing. Myocardial apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL staining. Serum angiotensin II (Ang II concentration was measured using the enzyme-linked immunosorbent assay (ELISA. Results. It was found that Wenxin Granule could partially reverse ventricular remodeling, improve heart function, alleviate the histopathological damage, inhibit myocardial apoptosis, and reduce Ang II concentration in rats with MI. Conclusions. The results of the current study suggest that Wenxin Granule may be a potential alternative and complementary medicine for the treatment of MI.

  9. Detection of myocardial perfusion defect with 320-row volume CT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Objective: To evaluate the feasibility of 320-row volume CT myocardial perfusion imaging (CT-MPI) in detecting myocardial perfusion defect. Methods: Fourteen patients with positive single-positron emission computed tomography myocardial perfusion imaging (SPECT-MPI) findings underwent both rest and adenosine stress 320-row volume CT-MPI. Rest and stress CT perfusion images were analyzed by employing dedicated software in 320-row CT workstation. Both SPECT-MPI and CT-MPI were evaluated for fixed and reversible perfusion defects using a 16-segment model (apex was excluded). The sensitivity, specificity of 320-row volume CT-MPI in detecting myocardial perfusion defect were evaluated by taking SPECT-MPI as a reference standard. Results: Both rest and stress 320-row volume CT-MPI were successfully performed in all patients. Thirty nine segments with fixed or reversible perfusion defects in all patients were depicted by SPECT-MPI, while 34 perfusion defects in 12 patients were identified by CT-MPI. The sensitivity, specificity of 320-row volume CT-MPI for detection of perfusion defects were 87.2%(34/39), 91.4% (169/185), respectively. Conclusion: 320-row volume CT-MPI has high sensitivity and specificity for detection of myocardial perfusion defects. (authors)

  10. Myocardial scintigraphy with 201Tl and quantitative assessment of myocardial blood flow

    International Nuclear Information System (INIS)

    A newly introduced radionuclide for myocardial imaging, 201-Tl, was studied. Twenty-two subjects consisting of 7 normals, 12 with ischemic heart disease and 3 with hypertrophic cardiomyopathy (HCM) were selected. On intravenous administration of 201-Tl(1.5 - 20. mCi), initial transit of the tracer through the heart, as well as subsequent uptake by the myocardium, were recorded by a scintillation camera. The later process showed the distribution of the myocardial blood flow (MBF). A normal myocardial scintigraphy revealed the left-sided myocardial mass predominantly, whereas the right side or the septum predominated in the case of tetralogy of fallot (T/F) or idiopathic hypertrophic subuaortic stenosis (IHSS). An ischemic or infarcted area of the myocardium in ischemic heart disease (IHD) was compatible with electrocardiographic findings, and revealed defects even in an equivocal case on ECG. Since the ratio of radioactivity taken up by the myocardium (U) to the total injected dosis (I) is assumed to be proportional to the fractional MBF of cardiac output (CO), MBF/CO is calculated by ratio of the radioactivity selected from myocardial region on the later recording to that from the entire region on the initial transit of the tracer bolus. The average MBF/CO of normals was 4.4 +- 0.5%, IHD 4.0 +- 0.8% and HCM 5.5 +- 1.2%. On exercise loading, a significant increase of this value was observed in normals, whereas no change was observed in IHD. (auth.)

  11. Myocardial ischemia in hypertrophic cardiomyopathy; Isquemia miocardica na cardiomiopatia hipertrofica

    Energy Technology Data Exchange (ETDEWEB)

    Lima Filho, Moyses de Oliveira; Figueiredo, Geraldo L.; Simoes, Marcus V.; Pyntia, Antonio O.; Marin Neto, Jose Antonio [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Div. de Cardiologia

    2000-08-01

    Myocardial ischemia in hypertrophic cardiomyopathy is multifactorial and explains the occurrence of angina, in about 50% of patients. The pathophysiology of myocardial ischemia may be explained by the increase of the ventricular mass and relative paucity of the coronary microcirculation; the elevated ventricular filling pressures and myocardial stiffness causing a compression of the coronary microvessels; the impaired coronary vasodilator flow reserve caused by anatomic and functional abnormalities; and the systolic compression of epicardial vessel (myocardial bridges). Myocardial ischemia must be investigated by perfusion scintigraphic methods since its presence influences the prognosis and has relevant clinical implications for management of patients. Patients with hypertrophic cardiomyopathy and documented myocardial ischemia usually need to undergo invasive coronary angiography to exclude the presence of concomitant atherosclerotic coronary disease. (author)

  12. Quantitative analysis of stress thallium-201 myocardial scintigrams: a multicenter trial

    International Nuclear Information System (INIS)

    Previously we validated a method for quantification of 201TI myocardial stress distribution and washout in which the patient's stress and washout circumferential profiles are compared with observed normal limits. The present study reports the results of a multicenter trial in which this method, utilizing normal limits from our institution, was employed to evaluate the presence, location, and extent of coronary artery disease (CAD). The normal limits utilized were generated from 49 patients having a low likelihood of CAD. The study population included 157 patients from four centers in the United States and Canada as well as a comparative prospective population from Cedars-Sinai Medical Center (CSMC) of 51 patients with CAD, 30 patients with normal coronary arteriograms, and 30 additional low-likelihood normals. The results in the combined centers regarding overall detection of CAD revealed a sensitivity of 84% and a frequency of test normality in the patients with low likelihood of CAD of 88%, compared to a sensitivity of 82% and true normalcy rate of 83% obtained in the prospective CSMC population. The sensitivity for detecting disease increased according to the extent of angiographic CAD in both the multicenter sites and the prospective CSMC group. Regarding localization of disease, similar sensitivities and specificities for detecting disease in individual coronary arteries were found in the multicenter sites and the prospective CSMC population. The results indicate that our method for quantifying 201TI stress-redistribution scintigrams utilizing standard normal limits can be applied at other institutions using a variety of scintillation cameras with similar accuracy to that currently obtained at our institution

  13. Validating a new methodology for strain estimation from cardiac cine MRI

    Science.gov (United States)

    Elnakib, Ahmed; Beache, Garth M.; Gimel'farb, Georgy; Inanc, Tamer; El-Baz, Ayman

    2013-10-01

    This paper focuses on validating a novel framework for estimating the functional strain from cine cardiac magnetic resonance imaging (CMRI). The framework consists of three processing steps. First, the left ventricle (LV) wall borders are segmented using a level-set based deformable model. Second, the points on the wall borders are tracked during the cardiac cycle based on solving the Laplace equation between the LV edges. Finally, the circumferential and radial strains are estimated at the inner, mid-wall, and outer borders of the LV wall. The proposed framework is validated using synthetic phantoms of the material strains that account for the physiological features and the LV response during the cardiac cycle. Experimental results on simulated phantom images confirm the accuracy and robustness of our method.

  14. Toll-Like Receptors and Myocardial Inflammation

    Directory of Open Access Journals (Sweden)

    Yan Feng

    2011-01-01

    Full Text Available Toll-like receptors (TLRs are a member of the innate immune system. TLRs detect invading pathogens through the pathogen-associated molecular patterns (PAMPs recognition and play an essential role in the host defense. TLRs can also sense a large number of endogenous molecules with the damage-associated molecular patterns (DAMPs that are produced under various injurious conditions. Animal studies of the last decade have demonstrated that TLR signaling contributes to the pathogenesis of the critical cardiac conditions, where myocardial inflammation plays a prominent role, such as ischemic myocardial injury, myocarditis, and septic cardiomyopathy. This paper reviews the animal data on (1 TLRs, TLR ligands, and the signal transduction system and (2 the important role of TLR signaling in these critical cardiac conditions.

  15. Painless acute myocardial infarction on Mount Kilimanjaro.

    Science.gov (United States)

    Jamal, Nasiruddin; Rajhy, Mubina; Bapumia, Mustaafa

    2016-01-01

    An individual experiencing dyspnoea or syncope at high altitude is commonly diagnosed to have high-altitude pulmonary edema or cerebral edema. Acute myocardial infarction (AMI) is generally not considered in the differential diagnosis. There have been very rare cases of AMI reported only from Mount Everest. We report a case of painless ST segment elevation myocardial infarction (STEMI) that occurred while climbing Mount Kilimanjaro. A 51-year-old man suffered dyspnoea and loss of consciousness near the mountain peak, at about 5600 m. At a nearby hospital, he was treated as a case of high-altitude pulmonary edema. ECG was not obtained. Two days after the incident, he presented to our institution with continued symptoms of dyspnoea, light-headedness and weakness, but no pain. He was found to have inferior wall and right ventricular STEMI complicated by complete heart block. He was successfully managed with coronary angioplasty, with good recovery. PMID:26989121

  16. Heart failure due to severe myocardial calcification

    International Nuclear Information System (INIS)

    A 28-year-old female who had had irradiation on the chest wall at the age of 5 as a remedy for keloid granulation after burn, recently developed congestive heart failure. Severe tricuspid regurgitation was demonstrated by echocardiography with a certain calcification in the cardiac shadow on chest radiogram. Calcified right ventricle and ventricular septum were noticed operatively, which disturbed ventricular motion and also caused tricuspid valve deformity. These calcified myocardium apparently corresponded with the irradiation field. After tricuspid valve replacement, she regained physical activity satisfactorily without congestive heart failure. Because she had no other known causes of cardiac calcification such as hypercalcemia, myocarditis, myocardial infarction or renal diseases, irradiation on the chest wall could be responsible for the severe myocardial calcification. (author)

  17. Relation of myocardial deformation to left ventricular geometry in the patients with maintenance hemodialysis uremia and preserved left ventricular ejection fraction%射血分数正常的尿毒症患者心肌形变与左心室构型的关系

    Institute of Scientific and Technical Information of China (English)

    王泓; 杨斌; 傅宁华; 孙晖; 李娟

    2011-01-01

    Objective To assess left ventricular myocardial deformation and their relation to left ventricular geometry in the patients of maintenance hemodialysis uremia with preserved left ventricular ejection fraction ( LVEF ). Methods The study population consisted of 80 uremia patients with preserved LVEF on a maintenance hemodialysis program, who took conventional echocardiography for systolic function and left ventricular geometry. Left ventricular geometry was assessed from left ventricular mass/height and relative wall thickness in combination. Peak systolic circumferential,radial and longitudinal strain and strain rate were measured by 2D speckle tracking imaging. Results Left ventricular remodeling was shown in 86.3% of patients:43.8% with concentric hypertrophy and 25.0% with eccentric hypertrophy.Concentric remodeling was found in 17. 5% of patients and normal geometry in 13.7%of patients. There was no signifficant difference in LVEF among these geometry groups. But the longitudinal strain and strain rate were lower in the patients with concentric hypertrophy and correlated with higher left ventricular mass index and relative wall thickness. Circumferential strain was lower in the group of eccentric hypertrophy compared with normal geometry. The radial strain and strain rate had no signifficant difference between four geometric groups. Conclusion In the patients with maintenance hemodialysis uremia, impaired left ventricular systolic function was found although LVEF was preserved. Lower longitudinal strain was related to concentric hypertrophy and higher left ventricular mass. These subtle changes in left ventricular contractility can be detected by 2D strain imaging.%目的 评价尿毒症维持性血液透析患者心肌形变与左心室构型的关系.方法 入选尿毒症维持性血液透析患者80例,左心室射血分数≥50%.常规超声心动图评价左心室构型,二维应变成像评价心肌不同方向收缩期

  18. Severe myocardial injury and extracorporeal membrane oxygenation following perinatal asphyxia

    OpenAIRE

    P Benson Ham; Pinkal Patel; Linda J. Wise; Christian Walters; Stansfield, Brian K.

    2015-01-01

    Perinatal asphyxia is a common cause of morbidity and mortality in the newborn and is associated with myocardial injury in a significant proportion of cases. Biomarkers, echocardiography, and rhythm disturbances are sensitive indicators of myocardial ischemia and may predict mortality. We present a case of severe myocardial dysfunction immediately after delivery managed with extracorporeal membrane oxygenation (ECMO) and discuss the role of cardiac biomarkers, echocardiography, electrocardiog...

  19. Anti-Cardiolipin Antibody in Acute Myocardial Infarction

    OpenAIRE

    Abdolreza S. Jahromi; Mohammad Shojaie; Samira Dana; Abdoulhossain Madani

    2010-01-01

    Problem statement: Myocardial infarction is the combined result of environmental and personal factors. Data concerning the relation between anti-Phospholipid (aPL) antibodies and myocardial infarction in subjects without evidence of overt autoimmune disease are conflicting. Anticardiolipin antibody is detected in various diseases like rheumatoid arthritis, systemic lupus erythematosus and anti-phospholipid antibody syndrome. The study of Anticardiolipin antibody in Acute Myocardial Infarction...

  20. The problems and the causes in viable myocardial detection

    International Nuclear Information System (INIS)

    Viable myocardial detection is very important in clinical practice. But the positive predictive value and specificities of all imagining modalities available are still relatively lower, and the causes may relative to the smooth of native or bridge coronary arteries after operation, the time to assess the function of viable myocardium, myocardial ischemia or damage after operation, the severity of left ventricular modification before revascularization and subendocardiac muscle scarring formation. The problems of viabile myocardial detection were still discussed here. (authors)

  1. Severe myocardial injury and extracorporeal membrane oxygenation following perinatal asphyxia

    Directory of Open Access Journals (Sweden)

    P. Benson Ham

    2015-05-01

    Full Text Available Perinatal asphyxia is a common cause of morbidity and mortality in the newborn and is associated with myocardial injury in a significant proportion of cases. Biomarkers, echocardiography, and rhythm disturbances are sensitive indicators of myocardial ischemia and may predict mortality. We present a case of severe myocardial dysfunction immediately after delivery managed with extracorporeal membrane oxygenation (ECMO and discuss the role of cardiac biomarkers, echocardiography, electrocardiography, and ECMO in the asphyxiated newborn.

  2. Double heart rupture after acute myocardial infarction: A case report

    OpenAIRE

    Ivanov Igor; Lovrenski Aleksandra; Dejanović Jadranka; Petrović Milovan; Jung Robert; Raffay Violetta

    2014-01-01

    Introduction. Double heart rupture is a rare complication of acute myocardial infarction with high mortality. Case report. We presented a 67-year-old female patient with symptoms and signs of myocardial infarction, diagnosed with echocardiography, rupture of the septum, the presence of a thrombus and a small pericardial effusion. Soon after admission the patient died. Autopsy revealed tamponade and double myocardial rupture, free wall rupture and ventricula...

  3. Sensitive Troponin Assay and the Classification of Myocardial Infarction

    OpenAIRE

    Shah, Anoop SV; McAllister, David A; Mills, Rosamund; Lee, Kuan Ken; Churchhouse, Antonia Md; Fleming, Kathryn M.; Layden, Elizabeth; Anand, Atul; Fersia, Omar; Joshi, Nikhil V; Walker, Simon; Jaffe, Allan S.; Fox, Keith Aa; Newby, David E; Mills, Nicholas L.

    2015-01-01

    Background Lowering the diagnostic threshold for troponin is controversial because it may disproportionately increase the diagnosis of myocardial infarction in patients without acute coronary syndrome. We assessed the impact of lowering the diagnostic threshold of troponin on the incidence, management, and outcome of patients with type 2 myocardial infarction or myocardial injury. Methods Consecutive patients with elevated plasma troponin I concentrations (≥50 ng/L; n = 2929) were classified ...

  4. Gallium-67 uptake in silent myocardial infarction: a case report

    International Nuclear Information System (INIS)

    Scintigrams obtained 24 and 48 hours after the injection of 67Ga in a patient undergoing evaluation for fever of unknown origin revealed positive myocardial uptake. The subsequent clinical course, electrocardiograms, radionuclear studies, and postmortem examination confirmed a silent myocardial infarction in the region of 67Ga localization. No other clinical reports were found of an acute myocardial infarction diagnosed by scintigraphy with 67Ga

  5. Geobacteraceae strains and methods

    Science.gov (United States)

    Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

    2015-07-07

    Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

  6. Diagnosis of myocardial ischemia in Kawasaki disease

    International Nuclear Information System (INIS)

    Thallium-201 myocardial imaging was performed at rest in 131 children with coronary arterial lesions due to Kawasaki disease. The coronary arterial lesions were assessed by selective coronary angiography within a few days of the isotope study. Twenty-one children ha d occlusive lesions, and segmental stenotic lesions were seen in 16 children. Perfusion defects of the myocardial images were detected in nine of the former and in three of the latter. The locations of the perfusion defects coincided with the perfusion areas of the affected vessels on coronary angiography. Twelve patients with initial perfusion defects at rest had a follow-up study and the defects disappeared in five. Myocardial imaging with exercise was performed in 27 patients including four with coronary arterial occlusion and two with segmental stenosis on coronary angiography. All with coronary artery lesions showed perfusion defects on the imaging with exercise, while the resting study showed the defects only in one patient, in whom more extensive perfusion defects were observed after exercise. Myocardial imaging following intravenous injection of dipyridamole was carried out in 43 patients. Perfusion defects after the injection were noted in 15 of 17 patients with coronary occlusion and in nine of 13 patients with segmental stenosis. In four patients with perfusion defects at rest, additional or more extensive defects were revealed by this drug in the areas of additional coronary arterial involvements. In 20 patients with perfusion defects only after dipyridamole injection, the perfusion defects coincided with the angiographic findings very well. A perfusion defect was documented following dipyridamole injection in one exceptional patient who had no stenotic lesions, but had three giant coronary aneurysms of the right coronary artery. Thus the dilated coronary lesions seemed to give a perfusion defect. (J.P.N.)

  7. Secondary Prevention in Acute Myocardial Infarction

    OpenAIRE

    IRMAK, Yrd.Doç.Dr. Zöhre; FESCİ, Doç.Dr. Hatice

    2005-01-01

    Recent studies on patients who had an acute myocardial infarction have shown that risk factors are decreased, atherosclerosis regressed, and re-infarction and mortality rates are reduced as a result of drug therapy in combination with the changes in the lifestyle. This treatment called as secondary prevention, requires a behavioral change in the lifestyle that includes stopping smoking, making healthy food choices, and increasing physical activity. Risk factors related with lifestyle, wh...

  8. Animal models of primary myocardial diseases.

    OpenAIRE

    Liu, S. K.; Tilley, L. P.

    1980-01-01

    Feline and canine cardiomyopathies (primary myocardial diseases) were reviewed and divided into three groups based on the clinical, hemodynamic, angiocardiographic, and pathologic findings: (1) feline and canine hypertrophic cardiomyopathy, (2) feline and canine congestive (dilated) cardiomyopathy, and (3) feline restrictive cardiomyopathy. All three groups consisted predominantly of mature adult male cats and dogs. Cardiomyopathy in the hamster and turkey was also reviewed. The most common p...

  9. Does Myocardial Bridging Affect Coronary Hemodynamics?

    OpenAIRE

    Onur Sildiroglu; Ferhat Cuce; Zafer Isilak; Muzaffer Saglam; Mehmet Incedayi; Kemal Kara; Ersin Ozturk

    2013-01-01

    Objective. The aim of our study was to evaluate the relationship between a myocardial bridge (MB) and its effects over the coronary artery hemodynamics by using multislice computed tomography (MSCT). Material and Methods. A total of 412 patients examined with coronary computed tomography (CT) angiography were reviewed retrospectively for an MB of the left anterior descending (LAD) coronary artery. We evaluated the correlation between the depth of an MB and the degree of compression to the...

  10. Molecular Imaging of Healing After Myocardial Infarction

    OpenAIRE

    Naresh, Nivedita K; Ben-Mordechai, Tamar; Leor, Jonathan; Epstein, Frederick H

    2011-01-01

    The progression from acute myocardial infarction (MI) to heart failure continues to be a major cause of morbidity and mortality. Potential new therapies for improved infarct healing such as stem cells, gene therapy, and tissue engineering are being investigated. Noninvasive imaging plays a central role in the evaluation of MI and infarct healing, both clinically and in preclinical research. Traditionally, imaging has been used to assess cardiac structure, function, perfusion, and viability. H...

  11. Myocardial Inflammation—Are We There Yet?

    OpenAIRE

    Greulich, Simon; Ferreira, Vanessa M; Dall’Armellina, Erica; Mahrholdt, Heiko

    2015-01-01

    Several exogenous or endogenous factors can lead to inflammatory heart disease. Beside infectious myocarditis, other systemic inflammatory disorders such as sarcoidosis, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), Churg-Strauss syndrome, and rheumatoid arthritis can affect the myocardium. Myocardial inflammation may have a major impact on the outcome of these patients, resulting in sudden cardiac death, severe arrhythmias, or end-stage heart failure. The current gold standar...

  12. Stroke and myocardial infarction: a terrible association

    OpenAIRE

    Bacci, Marcelo Rodrigues; Santos, Janaina Aparecida Boide

    2012-01-01

    In the USA coronary heart diseases and cerebral vascular accidents together are the major causes of death regardless of race or sex. More specifically, the acute myocardial infarction and the encephalic vascular accident, as final events of atherosclerosis, correspond to a large part of death cases. Such cases could be potentially prevented with a proper follow-up and the identification of the risk factors. We present a case of a 65-year-old black man, diabetic and hypertensive, with ischaemi...

  13. Technetium-99m myocardial imaging agents

    International Nuclear Information System (INIS)

    A major focus of cardiovascular radiopharmaceutical research over the past decade has been the search for a Tc-99m agent that could replace Tl-201, the current agent of choice for myocardial perfusion imaging. Recent advances in the inorganic chemistry of technetium, and in the translation of this chemistry to radiopharmaceutical development, make it very likely that this search will soon be successfully completed

  14. Acute Myocardial Infarction, 1992-2001.

    OpenAIRE

    Robert Schmitz

    2005-01-01

    Heart disease is the leading cause of hospitalization and death in the United States among persons age 65 and older. Acute myocardial infarction (AMI), more commonly known as heart attack, accounted for more than 321,000 hospitalizations among Medicare beneficiaries in 2001. This report presents trends in AMI hospitalization, readmission, and mortality rates from 1992 through 2001 among Medicare fee-for-service beneficiaries across various demographic groups.

  15. Myocardial infarction induced by spontaneous pneumothorax

    OpenAIRE

    Clarke, Viktoriya; McWilliams, Eric

    2010-01-01

    Chest pain is a very common condition. Patients may have a benign condition or present with a potentially lethal condition such as acute myocardial infarction, aortic dissection or tension pneumothorax. It is important to remember that patients may present with more than one serious pathology and that other serious conditions may potentially precipitate an acute coronary syndrome in a susceptible individual. We report the case of an elderly man with a background of chronic obstructive pulmona...

  16. Myocardial perfusion studies in coronary diseases

    International Nuclear Information System (INIS)

    For detecting in precocious form a coronary disease is necessary to apply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images,proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases

  17. Early detection of Myocardial Infarction using WBAN

    OpenAIRE

    Hadjem, Medina; Salem, Osman; Naït-Abdesselam, Farid; Ahmed, Mehaoua

    2013-01-01

    Cardiovascular diseases are the leading cause of death in the world, and Myocardial Infarction (MI) is the most serious one among those diseases. Patient monitoring for an early detection of MI is important to alert medical assistance and increase the vital prognostic of patients. With the development of wearable sensor devices having wireless transmission capabilities, there is a need to develop real-time applications that are able to accurately detect MI non-invasively. In this paper, we pr...

  18. Nonrigid registration of myocardial perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrigid...... registration algorithm based on free-form deformations due to Rueckert et al. Inspection of difference images from the wash-out part of the perfusion sequences indicates that a good registration accuracy is obtained....

  19. Fatigue in Older Adults Post Myocardial Infarction

    OpenAIRE

    Patricia Barton Crane; Jimmy eEfird; Willie Mae Abel

    2016-01-01

    Objective. The purpose of this study was to comprehensively examine putative factors that may independently contribute to fatigue and subsequent persistence of fatigue in elderly adults 6-8 months post myocardial infarction (MI). Studies suggest cardiac function, comorbidities, daytime sleepiness, depression, anemia, interleukins, and social support are correlates of fatigue; however, no studies have systematically examined these factors 6 months post MI in an aging population. Methods. Study...

  20. Acute myocardial infarction after mediastinal radiotherapy

    International Nuclear Information System (INIS)

    Mediastinal radiotherapy can affect the heart and great vessels to different degrees. It may turn up as coronary heart disease and less frequently as acute myocardial infarction. We report the case of a patient without coronary risk factors and an antecedent of mediastinal radiotherapy for Hodgkin's lymphoma. Considerations about mediastinal radiation as a risk factor for early development of coronary heart diseases are exposed. (author)

  1. Nonrigid registration of myocardial perfusion MRI

    OpenAIRE

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrigid registration algorithm based on free-form deformations due to Rueckert et al. Inspection of difference images from the wash-out part of the perfusion sequences indicates that a good registration ac...

  2. PARP inhibition and postinfarction myocardial remodeling.

    Science.gov (United States)

    Halmosi, Robert; Deres, Laszlo; Gal, Roland; Eros, Krisztian; Sumegi, Balazs; Toth, Kalman

    2016-08-01

    Coronary artery disease accounts for the greatest proportion of cardiovascular diseases therefore it is the major cause of death worldwide. Its therapeutic importance is indicated by still high mortality of myocardial infarction, which is one of the most severe forms of CVDs. Moreover, the risk of developing heart failure is very high among survivors. Heart failure is accompanied by high morbidity and mortality rate, therefore this topic is in the focus of researchers' interest. After a myocardial infarct, at first ventricular hypertrophy develops as a compensatory mechanism to decrease wall stress but finally leads to left ventricular dilation. This phenomenon is termed as myocardial remodeling. The main characteristics of underlying mechanisms involve cardiomyocyte growth, vessel changes and increased collagen production, in all of which several mechanical stress induced neurohumoral agents, oxidative stress and signal transduction pathways are involved. The long term activation of these processes ultimately leads to left ventricular dilation and heart failure with decreased systolic function. Oxidative stress causes DNA breaks producing the activation of nuclear poly(ADP-ribose) polymerase-1 (PARP-1) enzyme that leads to energy depletion and unfavorable modulation of different kinase cascades (Akt-1/GSK-3β, MAPKs, various PKC isoforms) and thus it promotes the development of heart failure. Therefore inhibition of PARP enzyme could offer a promising new therapeutical approach to prevent the onset of heart failure among postinfarction patients. The purpose of this review is to give a comprehensive summary about the most significant experimental results and mechanisms in postinfarction remodeling. PMID:27392900

  3. Multispectral optoacoustic tomography of myocardial infarction

    Science.gov (United States)

    Taruttis, Adrian; Wildgruber, Moritz; Kosanke, Katja; Beziere, Nicolas; Licha, Kai; Haag, Rainer; Aichler, Michaela; Walch, Axel; Rummeny, Ernst; Ntziachristos, Vasilis

    2012-01-01

    Objectives To investigate the feasibility of a high resolution optical imaging strategy for myocardial infarction. Background Near-infrared approaches to imaging cardiovascular disease enable visualization of disease-associated biological processes in vivo. However, even at the scale of small animals, the strong scattering of light prevents high resolution imaging after the first 1–2 mm of tissue, leading to degraded signal localization. Methods Multispectral optoacoustic tomography (MSOT) was used to non-invasively image myocardial infarction (MI) in a murine model of coronary artery ligation at resolutions not possible with current deep-tissue optical imaging methods. Post-MI imaging was based on resolving the spectral absorption signature of a dendritic polyglycerol sulfate-based (dPGS) near-infrared imaging agent targeted to P- and L-selectin. Results In vivo imaging succeeded in detection of the agent in the injured myocardium after intravenous injection. The high anatomic resolution (<200 μm) achieved by the described method allowed signals originating in the infarcted heart to be distinguished from uptake in adjacent regions. Histological analysis found dPGS signal in infarcted areas, originating from leukocytes and endothelial cells. Conclusions MSOT imaging of myocardial infarction provides non-invasive visualization of optical contrast with a high spatial resolution that is not degraded by the scattering of light. PMID:25327410

  4. Myocardial dysfunction following motor vehicle accidents

    International Nuclear Information System (INIS)

    Blunt chest trauma (BCT), with a high frequency of myocardial contusion, is a frequent complication of a large number of motor vehicle accidents (MVA). The purpose of this study is to determine the incidence and significance of this mechanism of myocardial damage. Left and right rest first pass radionuclide angiography (RNA) was performed 1-2 days following BCT in 74 consecutive patients. Serial ECG and CPK MB enzymes were determined. RNA was determined supine in 300 RAO projection following bolus injection of technetium-99m pertechnetate and acquired in list mode into a minicomputer. Right and left ventricular ejection fraction (RVEF and LVEF) and LV wall motion were determined (LVWM). 8/12 patients with abnormal acute RNA became normal in 30 days (72%). The high incidence of abnormalities noted on RNA and its reversibility after one month suggests the method as a very sensitive indicator of myocardial dysfunction following blunt chest trauma in MVA. The frequency of abnormalities of LVWM in patients with abnormal LVEF is consistent with focal direct injury and is considered a risk factor for emergency surgery

  5. Myocardial Perfusion Spect Imaging in Dextrocardia: A Case Report

    Directory of Open Access Journals (Sweden)

    Semra Özdemir

    2013-08-01

    Full Text Available The myocardial perfusion scintigraphy acquisition and analysis present some technical differences in the rare dextrocardia cases. Here we report a case of a 38 year-old woman with dextrocardia who had been applied myocardial perfusion scintigraphy. Presented case showed that the thoracic and abdominal organs had a mirror image with situs inversus totalis type dextrocardia. The incidence of coronary heart disease and life span of people with situs inversus totalis are the same as the normal population. So we may apply myocardial perfusion scintigraphy to this patient group. The current case is presented in order to remind the special applications of myocardial perfusion SPECT imaging in patients with dextrocardia.

  6. The prognostic importance of creatinine clearance after acute myocardial infarction

    DEFF Research Database (Denmark)

    Sørensen, C R; Brendorp, B; Rask-Madsen, C;

    2002-01-01

    AIMS: The purpose of this study was to assess renal dysfunction as an independent predictor of mortality after acute myocardial infarction. METHODS: The study population was 6252 patients with a myocardial infarction admitted alive from 1990 to 1992. The mortality status was obtained after at least.......9-1.3) respectively. CONCLUSION: Renal dysfunction is an important risk factor after acute myocardial infarction. When the risk is adjusted for available competing risk factors only severely reduced renal function is associated with an important and independent risk of mortality after acute myocardial infarction. The...

  7. Inferior ST-Elevation Myocardial Infarction Associated with Takotsubo Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Oliver Koeth

    2010-01-01

    Full Text Available Takotsubo cardiomyopathy (TCM is usually characterized by transient left ventricular apical ballooning. Due to the clinical symptoms which include chest pain, electrocardiographic changes, and elevated myocardial markers, Takotsubo cardiomyopathy is frequently mimicking ST-elevation myocardial infarction in the absence of a significant coronary artery disease. Otherwise an acute occlusion of the left anterior descending coronary artery can produce a typical Takotsubo contraction pattern. ST-elevation myocardial infarction (STEMI is frequently associated with emotional stress, but to date no cases of STEMI triggering TCM have been reported. We describe a case of a female patient with inferior ST-elevation myocardial infarction complicated by TCM.

  8. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas; Hasbak, Philip

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... diagnose and risk stratify CAD patients, while assessing the potential of the modality in clinical practice.......) identification of the extent of a multivessel coronary artery disease (CAD) burden, 2) patients with balanced 3-vessel CAD, 3) patients with subclinical CAD, and 4) patients with regional flow variance, despite of a high global MFR. A more accurate assessment of the ischemic burden in patients with intermediate...

  9. Stress and strain provide positional and directional cues in development.

    Directory of Open Access Journals (Sweden)

    Behruz Bozorg

    2014-01-01

    Full Text Available The morphogenesis of organs necessarily involves mechanical interactions and changes in mechanical properties of a tissue. A long standing question is how such changes are directed on a cellular scale while being coordinated at a tissular scale. Growing evidence suggests that mechanical cues are participating in the control of growth and morphogenesis during development. We introduce a mechanical model that represents the deposition of cellulose fibers in primary plant walls. In the model both the degree of material anisotropy and the anisotropy direction are regulated by stress anisotropy. We show that the finite element shell model and the simpler triangular biquadratic springs approach provide equally adequate descriptions of cell mechanics in tissue pressure simulations of the epidermis. In a growing organ, where circumferentially organized fibers act as a main controller of longitudinal growth, we show that the fiber direction can be correlated with both the maximal stress direction and the direction orthogonal to the maximal strain direction. However, when dynamic updates of the fiber direction are introduced, the mechanical stress provides a robust directional cue for the circumferential organization of the fibers, whereas the orthogonal to maximal strain model leads to an unstable situation where the fibers reorient longitudinally. Our investigation of the more complex shape and growth patterns in the shoot apical meristem where new organs are initiated shows that a stress based feedback on fiber directions is capable of reproducing the main features of in vivo cellulose fiber directions, deformations and material properties in different regions of the shoot. In particular, we show that this purely mechanical model can create radially distinct regions such that cells expand slowly and isotropically in the central zone while cells at the periphery expand more quickly and in the radial direction, which is a well established growth pattern

  10. Strain-Based Design Methodology of Large Diameter Grade X80 Linepipe

    Energy Technology Data Exchange (ETDEWEB)

    Lower, Mark D. [ORNL

    2014-04-01

    Continuous growth in energy demand is driving oil and natural gas production to areas that are often located far from major markets where the terrain is prone to earthquakes, landslides, and other types of ground motion. Transmission pipelines that cross this type of terrain can experience large longitudinal strains and plastic circumferential elongation as the pipeline experiences alignment changes resulting from differential ground movement. Such displacements can potentially impact pipeline safety by adversely affecting structural capacity and leak tight integrity of the linepipe steel. Planning for new long-distance transmission pipelines usually involves consideration of higher strength linepipe steels because their use allows pipeline operators to reduce the overall cost of pipeline construction and increase pipeline throughput by increasing the operating pressure. The design trend for new pipelines in areas prone to ground movement has evolved over the last 10 years from a stress-based design approach to a strain-based design (SBD) approach to further realize the cost benefits from using higher strength linepipe steels. This report presents an overview of SBD for pipelines subjected to large longitudinal strain and high internal pressure with emphasis on the tensile strain capacity of high-strength microalloyed linepipe steel. The technical basis for this report involved engineering analysis and examination of the mechanical behavior of Grade X80 linepipe steel in both the longitudinal and circumferential directions. Testing was conducted to assess effects on material processing including as-rolled, expanded, and heat treatment processing intended to simulate coating application. Elastic-plastic and low-cycle fatigue analyses were also performed with varying internal pressures. Proposed SBD models discussed in this report are based on classical plasticity theory and account for material anisotropy, triaxial strain, and microstructural damage effects

  11. Evaluation of myocardial blood supply using adenosine stress myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Objective: To retrospectively evaluate the value and accuracy of adenosine stress and rest SPECT myocardial perfusion imaging. Methods: A total of 1858 patients who were suspected or known for coronary artery disease (CAD) underwent 99Tcm-methoxyisobutylisonitrile (MIBI) myocardial perfusion SPECT with adenosine infusion using the standard 2-day protocol. Images were interpreted by two or more experienced nuclear medicine physicians. Coronary angiography was carried out in all patients within one month. Kappa test was used to analyze the correlation between the two imaging studies. Results: By coronary angiography, there were 957 patients diagnosed of CAD (one-, two-, three-vessel disease: 506, 256, 195, respectively) and 901 normal. Stenosis was found in 1603 vessels, including left anterior descending coronary artery (LAD): 765, left circumflex coronary artery (LCX): 399 and right coronary artery (RCA): 439. By adenosine induced stress myocardial perfusion imaging, 876 patients were diagnosed of myocardial ischemia (sensitivity: 876/957, 91.54%) and 651 patients had negative findings (specificity: 651/901,72.25 %). The positive and negative predictive values were 77.80% (876/1126) and 88.93% (651/732), respectively. The correlation coefficient between the two imaging studies was 0.641. The vessel-based sensitivity was 81.31% (622/765) for LAD, 56.64% (226/399) for LCX and 70.62% (310/439) for RCA, respectively. The sensitivity for detection of one-, two-, three-vessel stenosis was 87.55% (443/506), 94.92% (243/256) and 97.44% (190/195), respectively. The side-effects was mild and transient with an incidence rate of 84.12% (1563/1858), without major cardiac events. Conclusion: Stress myocardial perfusion imaging induced by adenosine is reliable for the evaluation of myocardial blood supply in CAD patients. (authors)

  12. Depressive symptoms are associated with mental stress-induced myocardial ischemia after acute myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Jingkai Wei

    Full Text Available Depression is an adverse prognostic factor after an acute myocardial infarction (MI, and an increased propensity toward emotionally-driven myocardial ischemia may play a role. We aimed to examine the association between depressive symptoms and mental stress-induced myocardial ischemia in young survivors of an MI.We studied 98 patients (49 women and 49 men age 38-60 years who were hospitalized for acute MI in the previous 6 months. Patients underwent myocardial perfusion imaging at rest, after mental stress (speech task, and after exercise or pharmacological stress. A summed difference score (SDS, obtained with observer-independent software, was used to quantify myocardial ischemia under both stress conditions. The Beck Depression Inventory-II (BDI-II was used to measure depressive symptoms, which were analyzed as overall score, and as separate somatic and cognitive depressive symptom scores.There was a significant positive association between depressive symptoms and SDS with mental stress, denoting more ischemia. After adjustment for demographic and lifestyle factors, disease severity and medications, each incremental depressive symptom was associated with 0.14 points higher SDS. When somatic and cognitive depressive symptoms were examined separately, both somatic [β = 0.17, 95% CI: (0.04, 0.30, p = 0.01] and cognitive symptoms [β = 0.31, 95% CI: (0.07, 0.56, p = 0.01] were significantly associated with mental stress-induced ischemia. Depressive symptoms were not associated with ischemia induced by exercise or pharmacological stress.Among young post-MI patients, higher levels of both cognitive and somatic depressive symptoms are associated with a higher propensity to develop myocardial ischemia with mental stress, but not with physical (exercise or pharmacological stress.

  13. Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

    International Nuclear Information System (INIS)

    Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min-1 g-1, whereas stress MBF was 3.15±1.93 ml min-1 g-1 and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

  14. Abnormal myocardial capillary density in apical hypertrophic cardiomyopathy can be assessed by myocardial contrast echocardiography

    International Nuclear Information System (INIS)

    Myocardial ischemia and dysfunction can occur in hypertrophic cardiomyopathy (HCM) because of the high muscle-to-blood ratio, even without significant coronary artery disease. Microbubbles reside only in the intravascular space and myocardial video-intensity during systole results mostly from microbubbles within capillaries. The hypothesis explored in the present study was that an abnormal capillary density in apical HCM (ApHCM) can be demonstrated using myocardial contrast echocardiography (MCE). The 56 patients were investigated (31 males, age 58±9 years; 33 ApHCM, 9 hypertensive left ventricular hypertrophy [LVH], 14 controls). MCE was performed with low-mechanical-index power modulation imaging. Tissue Doppler imaging to assess myocardial contractile function was obtained at the mitral annulus (S'), and 99mTc-MIBI single photon emission computed tomography (SPECT) was also performed. All ApHCM patients exhibited perfusion defects at the hypertrophied segments in the systolic phase during MCE, whereas SPECT showed normal or rather increased perfusion at those sites. The cyclic variation of video-intensity was exaggerated in ApHCM when compared with the LVH or control group (% of [systolic video-intensity]/[diastolic video-intensity]: 33.0±12.3%, 88.3±19.2% and 79.4±13.9%, respectively [P<0.05]). Concurrently, MCE cyclic variation and perfusion defect size were related to decreased S' (P<0.05 for all). A perfusion defect at the hypertrophied segment, representing abnormal myocardial capillary density, was observed in ApHCM patients during MCE. The extent of MCE cyclic variation and the perfusion defect size both correlate with decreased myocardial contractile property in ApHCM. (author)

  15. Experimental Investigation of Strain Concentration Evaluation Based on the Stress Redistribution Locus Method

    International Nuclear Information System (INIS)

    Evaluation of local strain at structural discontinuities is an important technology in high temperature design of fast reactors because the failure mode in high temperature fatigue or creep fatigue damage is usually crack initiation and growth from such a locally high strained area. A rationalized strain concentration evaluation method was discussed experimentally in this study. The stress redistribution locus (SRL) method had been proposed to improve the accuracy of local stress and strain evaluation for structural discontinuities. This method based on a concept that the locus of stress redistribution from elastic to inelastic state, or during relaxation strongly depends on the structure, and the locus almost coincides with the locus obtained by elastic-creep analysis. High temperature fatigue tests of circumferentially notched specimens were conducted accompanying with local strain measurement by a capacitance type strain gage. Measured strain was compared with the prediction by the SRL method and the applicability of the method is discussed. The SRL method improves the accuracy of inelastic strain estimation with keeping conservativeness in comparison with the Neuber's rule which is used in high temperature design codes. (author)

  16. "Mushroom cloud": a giant left ventricular pseudoaneurysm after a myocardial infarction due to myocardial bridging – a case report

    OpenAIRE

    Ferreira Manuel M; Gouveia Raquel A; Lima Sónia; Santos Miguel; Andrade Maria; Gomes Renata; Silva José

    2009-01-01

    Abstract Left ventricular pseudoaneurysm is an uncommon complication after transmural myocardial infarction, occurring when a free wall rupture is contained by adhesions of the overlying pericardium preventing acute tamponade. In this report, an unusual case of a 61 year-old male with a giant apical left ventricular pseudoaneurysm after an unnoticed myocardial infarction is presented. On coronary angiogram myocardial bridging of the distal left anterior descending artery was judged to be the ...

  17. Influence of the myocardial bridging phenomenon on the myocardial structure and the coronary arteries wall structure changes

    OpenAIRE

    Tomanović-Koković Jelena; Teofilovski-Parapid Gordana; Oklobdžija Mirjana; Kanjuh Vladimir; Kovačević Slobodan; Parapid Biljana; Koković Vladimir

    2006-01-01

    Background/Aim. Our research was performed to evaluate the influences of the myocardial bridging of coronary arteries on the myocardial and coronary arteries wall structure changes, that could be a reason for multiple heart malfunctions. Methods. We analyzed the autopsy material, collected during a five-years period, and especially the group of 575 cases with the major aim to diagnose mors naturalis. In all cases with the presence of myocardial bridge over the arterial coronary wall revealed ...

  18. Short-Term Hyperglycemic Dysregulation in Patients With Type 1 Diabetes Does Not Change Myocardial Triglyceride Content or Myocardial Function

    OpenAIRE

    Hammer, Sebastiaan; Jonker, Jacqueline T; Lamb, Hildo J.; Rutger W van der Meer; Zondag, Wendy; Sepers, Jan M.; de Roos, Albert; Johannes W A Smit; Romijn, Johannes A.

    2008-01-01

    OBJECTIVE—To evaluate the effects of hyperglycemia due to partial insulin deprivation on myocardial triglyceride (TG) content and myocardial function in patients with type 1 diabetes. RESEARCH DESIGN AND METHODS—Myocardial and hepatic TG content and left ventricular (LV) function were measured by magnetic resonance (MR) spectroscopy and MR imaging during optimal glucoregulation and after 24 h of partial insulin deprivation (n = 10). RESULTS—Mean insulin infusion rate was 45 ± 5 units at basel...

  19. Histochemical and immunohistochemical analyses of the myocardial scar fallowing acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Tatić Vujadin

    2012-01-01

    Full Text Available Background/Aim. The heart has traditionally been considered as a static organ without capacity of regeneration after trauma. Currently, the more and more often asked question is whether the heart has any intrinsic capacities to regenerate myocytes after myocardial infarction. The aim of this study was to present the existence of the preserved muscle fibers in the myocardial scar following myocardial infarction as well as the presence of numerous cells of various size and form that differently reacted to the used immunohistochemical antibodies. Methods. Histological, histochemical and immunohistochemical analyses of myocardial sections taken from 177 patients who had died of acute myocardial infarction and had the myocardial scar following myocardial infarction, were carried out. More sections taken both from the site of acute infarction and scar were examined by the following methods: hematoxylin-eosin (HE, periodic acid schiff (PAS, PAS-diastasis, Masson trichrom, Malory, van Gieson, vimentin, desmin, myosin, myoglobin, alpha actin, smoth muscle actin (SMA, p53, leukocyte common antigen (LCA, proliferating cell nuclear antigen (PCNA, Ki-67, actin HHF35, CD34, CD31, CD45, CD45Ro, CD8, CD20. Results. In all sections taken from the scar region, larger or smaller islets of the preserved muscle fibers with the signs of hypertrophy were found. In the scar, a large number of cells of various size and form: spindle, oval, elongated with abundant cytoplasm, small with one nucleus and cells with scanty cytoplasm, were found. The present cells differently reacted to histochemical and immunohistochemical methods. Large oval cells showed negative reaction to lymphocytic and leukocytic markers, and positive to alpha actin, actin HHF35, Ki-67, myosin, myoglobin and desmin. Elongated cells were also positive to those markers. Small mononuclear cells showed positive reaction to lymphocytic markers. Endothelial and smooth muscle cells in the blood vessel walls

  20. Muscle strain (image)

    Science.gov (United States)

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  1. Muscle strain treatment

    Science.gov (United States)

    Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...

  2. Circumferential lesion formation around the pulmonary veins in the left atrium with focused ultrasound using a 2D-array endoesophageal device: a numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Pichardo, Samuel; Hynynen, Kullervo [Imaging Research-Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room C713, Toronto, ON M4N 3M5 (Canada)

    2007-08-21

    Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia affecting humans. The electrical isolation by ablation of the pulmonary veins (PVs) in the left atrium (LA) of the heart has been proven as an effective cure of AF. The ablation consists mainly in the formation of a localized circumferential thermal coagulation of the cardiac tissue surrounding the PVs. In the present numerical study, the feasibility of producing the required circumferential lesion with an endoesophageal ultrasound probe is investigated. The probe operates at 1 MHz and consists of a 2D array with enough elements (114 x 20) to steer the acoustic field electronically in a volume comparable to the LA. Realistic anatomical conditions of the thorax were considered from the segmentation of histological images of the thorax. The cardiac muscle and the blood-filled cavities in the heart were identified and considered in the sound propagation and thermal models. The influence of different conditions of the thermal sinking in the LA chamber was also studied. The circumferential ablation of the PVs was achieved by the sum of individual lesions induced with the proposed device. Different scenarios of lesion formation were considered where ultrasound exposures (1, 2, 5 and 10 s) were combined with maximal peak temperatures (60, 70 and 80 {sup 0}C). The results of this numerical study allowed identifying the limits and best conditions for controlled lesion formation in the LA using the proposed device. A controlled situation for the lesion formation surrounding the PVs was obtained when the targets were located within a distance from the device in the range of 26 {+-} 7 mm. When combined with a maximal temperature of 70 {sup 0}C and an exposure time between 5 and 10 s, this distance ensured preservation of the esophageal structures, controlled lesion formation and delivery of an acoustic intensity at the transducer surface that is compatible with existing materials. With a peak

  3. Is crack branching under shear loading caused by shear fracture? ——A critical review on maximum circumferential stress theory

    Institute of Scientific and Technical Information of China (English)

    孙宗颀

    2001-01-01

    When a crack is subjected to shear force, crack branching usually occurs. Theoretical study shows that the crack branching under shear loading is caused by tensile stress, but not caused by shear fracture. The co-plane shear fracture could be obtained if compressive stress with given direction is applied to the specimen, subsequently, calculated shear fracture toughness, KⅡ C, is larger than KⅠ C. A prerequisite of possible occurrence of mode Ⅱ fracture was proposed. The study of shear fracture shows that the maximum circumferential stress theory considered its criterion as a parametric equation of a curve in KⅠ, KⅡ plane is incorrect; the predicted ratio KⅡ C/KⅠ C=0.866 is incorrect too.

  4. Application of fracture-proof design methods using tearing-instability theory to nuclear piping postulating circumferential through-wall cracks

    International Nuclear Information System (INIS)

    This report presents methods of applying tearing instability analysis to large circumferential through-wall cracks in piping to demonstrate cases of adequate ductility to avoid double ended break. The first part gives results of applying simplified rigid-plastic cracked section analysis to some typical piping systems and subsequently gives some additional refinements of this type of analysis. The second part presents full elastic-plastic cracked section analysis which demonstrates the adequacy of rigid-plastic analysis for most cases and provides the methodology where elastic-plastic analysis is required. The results combined with adequate treatment of material property data and other deformation limiting and load limiting aspects of as-built piping systems, provides a complete analysis of subject

  5. A method for the measurement of dispersion curves of circumferential guided waves radiating from curved shells: experimental validation and application to a femoral neck mimicking phantom

    Science.gov (United States)

    Nauleau, Pierre; Minonzio, Jean-Gabriel; Chekroun, Mathieu; Cassereau, Didier; Laugier, Pascal; Prada, Claire; Grimal, Quentin

    2016-07-01

    Our long-term goal is to develop an ultrasonic method to characterize the thickness, stiffness and porosity of the cortical shell of the femoral neck, which could enhance hip fracture risk prediction. To this purpose, we proposed to adapt a technique based on the measurement of guided waves. We previously evidenced the feasibility of measuring circumferential guided waves in a bone-mimicking phantom of a circular cross-section of even thickness. The goal of this study is to investigate the impact of the complex geometry of the femoral neck on the measurement of guided waves. Two phantoms of an elliptical cross-section and one phantom of a realistic cross-section were investigated. A 128-element array was used to record the inter-element response matrix of these waveguides. This experiment was simulated using a custom-made hybrid code. The response matrices were analyzed using a technique based on the physics of wave propagation. This method yields portions of dispersion curves of the waveguides which were compared to reference dispersion curves. For the elliptical phantoms, three portions of dispersion curves were determined with a good agreement between experiment, simulation and theory. The method was thus validated. The characteristic dimensions of the shell were found to influence the identification of the circumferential wave signals. The method was then applied to the signals backscattered by the superior half of constant thickness of the realistic phantom. A cut-off frequency and some portions of modes were measured, with a good agreement with the theoretical curves of a plate waveguide. We also observed that the method cannot be applied directly to the signals backscattered by the lower half of varying thicknesses of the phantom. The proposed approach could then be considered to evaluate the properties of the superior part of the femoral neck, which is known to be a clinically relevant site.

  6. 环形大腿吸脂术150例体会%A clinical analysis of circumferential thigh liposuction: 150 cases report

    Institute of Scientific and Technical Information of China (English)

    黎石峰; 李俊明; 张昕霞; 江华; 李琳

    2013-01-01

    目的 探讨一种安全有效的大腿吸脂塑形的方法.方法 自2008年4月至2012年5月,采用持续硬膜外麻醉+肿胀麻醉下行360°环形吸脂术,对150例求美者大腿进行吸脂塑形.结果 本组求美者150例,术中麻醉效果好,出血少,术后随访3~9个月,吸脂塑形效果好,并发症少.结论 持续硬膜外麻醉+肿胀麻醉下行360°环形大腿吸脂术是一种安全、有效的方法,值得临床推广.%Objective To explore a safe and effective liposuction method for the thigh lipostructure.Methods From April 2008 to May 2012,circumferential bilateral thigh liposuction under continuous epidural anesthesia combined with local tumescent anesthesia was performed on 150 cases.Results Satisfactory results were received with good intraoperative anesthetic effect and less bleeding.After 3 to 9 months follow-up,satisfied thigh contour was obtained in all cases with few postoperative complications.Conclusion Circumferential thigh liposuction under continuous epidural anesthesia combined with local tumescent anesthesia is a safe and efficacy approach for thigh lipostructure.

  7. 基于PLC的钢管环缝焊接性能研究%Performance of circumferential welding for steel tube based on PLC

    Institute of Scientific and Technical Information of China (English)

    陈怀忠; 许雪贵; 黄芳

    2014-01-01

    PLC technique was applied for controlling the CO2 gas shielded welding process of circumferential welding for 20MnCr steel tube. The corrosion resistance,thermal fatigue resistance,tensile and impact properties were tested and analyzed. The results show that compared with the common control method,the PLC control technique can obtain better corrosion resistance, thermal fatigue resistance,tensile and impact properties of welding joint. After neutral salt-spray corrosion for 240 h,the mass loss rate of circumferential welding joint by PLC technique decreases by 65%,tensile strength at 20℃increases by 15%,and impact energy at 20℃increases by 26%.%在20MnCr钢管环缝CO2气体保护焊控制过程中引入PLC技术,进行焊接接头耐腐蚀性能、抗热疲劳性能、拉伸和冲击性能的测试与对比分析。结果表明:与传统控制技术相比,采用PLC技术获得的焊接接头具有更优的耐腐蚀性能、抗热疲劳性能、拉伸和冲击性能;经过240 h中性盐雾腐蚀后质量损失率降低了65%;20℃抗拉强度增加15%、冲击吸收功增加26%。

  8. A method for the measurement of dispersion curves of circumferential guided waves radiating from curved shells: experimental validation and application to a femoral neck mimicking phantom.

    Science.gov (United States)

    Nauleau, Pierre; Minonzio, Jean-Gabriel; Chekroun, Mathieu; Cassereau, Didier; Laugier, Pascal; Prada, Claire; Grimal, Quentin

    2016-07-01

    Our long-term goal is to develop an ultrasonic method to characterize the thickness, stiffness and porosity of the cortical shell of the femoral neck, which could enhance hip fracture risk prediction. To this purpose, we proposed to adapt a technique based on the measurement of guided waves. We previously evidenced the feasibility of measuring circumferential guided waves in a bone-mimicking phantom of a circular cross-section of even thickness. The goal of this study is to investigate the impact of the complex geometry of the femoral neck on the measurement of guided waves. Two phantoms of an elliptical cross-section and one phantom of a realistic cross-section were investigated. A 128-element array was used to record the inter-element response matrix of these waveguides. This experiment was simulated using a custom-made hybrid code. The response matrices were analyzed using a technique based on the physics of wave propagation. This method yields portions of dispersion curves of the waveguides which were compared to reference dispersion curves. For the elliptical phantoms, three portions of dispersion curves were determined with a good agreement between experiment, simulation and theory. The method was thus validated. The characteristic dimensions of the shell were found to influence the identification of the circumferential wave signals. The method was then applied to the signals backscattered by the superior half of constant thickness of the realistic phantom. A cut-off frequency and some portions of modes were measured, with a good agreement with the theoretical curves of a plate waveguide. We also observed that the method cannot be applied directly to the signals backscattered by the lower half of varying thicknesses of the phantom. The proposed approach could then be considered to evaluate the properties of the superior part of the femoral neck, which is known to be a clinically relevant site. PMID:27272197

  9. Assessment of myocardial fatty acid metabolism in patients with angina pectoris and diabetes mellitus using {sup 123}I-BMIPP myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kazuki; Tanabe, Takuji; Yuba, Tatsuya; Doue, Tomoki; Adachi, Yoshihiko; Katoh, Shuuji [Asahi Univ., Gifu (Japan). Murakami Memorial Hospital; Sugihara, Hiroki; Azuma, Akihiro; Nakagawa, Masao

    2001-11-01

    We studied the effect of myocardial ischemia and diabetes mellitus (DM) on the myocardial fatty acid metabolism using {sup 123}I-BMIPP myocardial scintigraphy. We performed {sup 123}I-BMIPP myocardial scintigraphy in 50 patients with myocardial ischemia and without DM (AP), in 30 patients with myocardial ischemia and DM (AP+DM), 12 patients with DM and without myocardial ischemia (DM), and in 10 normal subjects (N). Myocardial uptake rate of {sup 123}I-BMIPP was obtained using the time activity curve. Myocardial washout rate of {sup 123}I-BMIPP was calculated using the polar images of early and delayed SPECT images. Myocardial uptake rate of {sup 123}I-BMIPP (%) were AP: 4.9{+-}0.6, AP+DM: 5.5{+-}0.5, DM 5.7{+-}0.5 and N: 5.0{+-}0.4. {sup 123}I-BMIPP myocardial uptake rate was increased in AP+DM and DM. {sup 123}I-BMIPP myocardial washout rate (%) were AP: 30.2{+-}4.3, AP+DM: 24.5{+-}3.9, DM: 16.1{+-}2.8 and N: 19.4{+-}3.2. {sup 123}I-BMIPP myocardial washout rate was increased in AP and AP+DM. {sup 123}I-BMIPP myocardial washout rate was increased particularly in patients with multi-vessels disease. {sup 123}I-BMIPP myocardial washout rate was decreased in DM. The present study suggested that diabetes mellitus increased myocardial fatty acid uptake and decreased myocardial fatty acid washout, and that myocardial ischemia increased myocardial fatty acid washout. (author)

  10. Assessment of myocardial fatty acid metabolism in patients with angina pectoris and diabetes mellitus using 123I-BMIPP myocardial scintigraphy

    International Nuclear Information System (INIS)

    We studied the effect of myocardial ischemia and diabetes mellitus (DM) on the myocardial fatty acid metabolism using 123I-BMIPP myocardial scintigraphy. We performed 123I-BMIPP myocardial scintigraphy in 50 patients with myocardial ischemia and without DM (AP), in 30 patients with myocardial ischemia and DM (AP+DM), 12 patients with DM and without myocardial ischemia (DM), and in 10 normal subjects (N). Myocardial uptake rate of 123I-BMIPP was obtained using the time activity curve. Myocardial washout rate of 123I-BMIPP was calculated using the polar images of early and delayed SPECT images. Myocardial uptake rate of 123I-BMIPP (%) were AP: 4.9±0.6, AP+DM: 5.5±0.5, DM 5.7±0.5 and N: 5.0±0.4. 123I-BMIPP myocardial uptake rate was increased in AP+DM and DM. 123I-BMIPP myocardial washout rate (%) were AP: 30.2±4.3, AP+DM: 24.5±3.9, DM: 16.1±2.8 and N: 19.4±3.2. 123I-BMIPP myocardial washout rate was increased in AP and AP+DM. 123I-BMIPP myocardial washout rate was increased particularly in patients with multi-vessels disease. 123I-BMIPP myocardial washout rate was decreased in DM. The present study suggested that diabetes mellitus increased myocardial fatty acid uptake and decreased myocardial fatty acid washout, and that myocardial ischemia increased myocardial fatty acid washout. (author)

  11. Prognostic value of myocardial sympathetic activity in patients with asymptomatic myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Narita, Michihiro; Kurihara, Tadashi; Sindoh, Takashi; Sawada, Yoshihiro [Sumitomo Hospital, Osaka (Japan)

    1999-04-01

    To clarify the significance of myocardial sympathetic activity in patients with asymptomatic myocardial infarction (MI), we performed {sup 123}I-metaiodobenzyl-guanidine (MIBG) and {sup 201}Tl imaging at rest. We calculated the ratio of cardiac uptake of the isotope to the total injected dose (%Uptake), percent washout of MIBG over 3 hours and the Uptake Ratio (UR, %Uptake of MIBG divided by %Uptake of {sup 201}Tl). We compared these indices with clinical findings, exercise stress-rest myocardial perfusion imaging with {sup 99}Tc-methoxy-2-isobutyl isonitrile, coronary angiography, echocardiography and neurohumoral findings. During the follow-up period of 19.9{+-}10.3 months in 32 patients, events (heart failure or cardiac death) developed in 10 (31%). In univariate analysis, diabetes mellitus, atrial fibrillation, left ventricular end-diastolic dimension (LVDd) greater than 54 mm, and the %Uptake of MIBG and UR differed significantly between event and event-free groups. Cox proportional hazard model showed that the UR was a predictor of events (p=0.0007). In patients with UR less than 0.58, the relative risk of events was 19.1 times greater than in patients with an UR greater than 0.58. UR was closely correlated to LVDd (r=-0.578, p=0.01) suggesting that myocardial sympathetic activity is related to LV remodeling after MI. MIBG imaging provides important information regarding the prognosis and the pathophysiologic process of asymptomatic MI. (author)

  12. Evaluation of myocardial involvement in Duchenne progressive muscular dystrophy with thallium-201 myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Myocardial involvement in progressive muscular dystrophy of the Duchenne type was evaluated in 19 patients using thallium-201 myocardial perfusion imaging. The qualitative analysis was performed in anterior, 3 left anterior oblique and left lateral projection images by three experienced physicians. Distinct perfusion defects were shown in 13 patients, especially in LV posterolateral or posterior walls (11 patients). There was no significant relationship between the presence of perfusion defects and the skeletal muscle changes or thoracic deformities assessed by transmission computed tomography. Slightly increased thallium-201 activity in RV free wall and lungs was shown in nine and one patient, respectively. The extensive perfusion defects were shown in 2 patients who died of congestive heart failure 1 to 2 years after the scintigraphic study. The myocardial scintigraphic changes were considered to be minimal in 7 of 9 patients who underwent two serial scintigraphic studies in 2 to 3 years. It was concluded that the thallium myocardial perfusion imaging was a useful clinical technique to evaluate the cardiomyopathy in Duchenne progressive muscular dystrophy. (author)

  13. Evaluation of myocardial involvement in Duchenne progressive muscular dystrophy with thallium-201 myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Naoki; Yamamoto, Shuhei; Okada, Mitsuhiro (Nagoya Univ. (Japan). Faculty of Medicine)

    1983-12-01

    Myocardial involvement in progressive muscular dystrophy of the Duchenne type was evaluated in 19 patients using thallium-201 myocardial perfusion imaging. The qualitative analysis was performed in anterior, 3 left anterior oblique and left lateral projection images by three experienced physicians. Distinct perfusion defects were shown in 13 patients, especially in LV posterolateral or posterior walls (11 patients). There was no significant relationship between the presence of perfusion defects and the skeletal muscle changes or thoracic deformities assessed by transmission computed tomography. Slightly increased thallium-201 activity in RV free wall and lungs was shown in nine and one patient, respectively. The extensive perfusion defects were shown in 2 patients who died of congestive heart failure 1 to 2 years after the scintigraphic study. The myocardial scintigraphic changes were considered to be minimal in 7 of 9 patients who underwent two serial scintigraphic studies in 2 to 3 years. It was concluded that the thallium myocardial perfusion imaging was a useful clinical technique to evaluate the cardiomyopathy in Duchenne progressive muscular dystrophy.

  14. Protective effects of betaglucin on myocardial tissue during myocardial infarction in rats and dogs

    Institute of Scientific and Technical Information of China (English)

    Jiao QIAN; Ai-jun LIU; Wei ZHANG; Zhi-peng WEN; Lili LIN; Jing-hang WANG; Ding-feng SU; Jian-guo LIU

    2009-01-01

    Aim: To test the protective effects of betaglucin, a novel beta-glucan, on models of myocardial infarction (MI) in rats and dogs.Methods: The left anterior descending (LAD) coronary artery occlusion model was used to induce an MI in rats and dogs. Three doses of betaglucin (10, 30 and 100 mg/kg), propranolol (positive control, 1 mg/kg) and vehicle alone (5% glucose solution) were adminis-tered before LAD occlusion, and characteristics of the resulting MI were subsequently assessed. In anesthetized dogs, blood pressure,heart rate, ventricular function, coronary artery blood flow and myocardial oxygen consumption were determined before and after the drug administration.Results: The MI mass in both rats and dogs was significantly reduced by betaglucin (30 and 100 mg/kg, P0.05). High-dose betaglucin (100 mg/kg) increased myocar-dial oxygen consumption, but not to a statistically significant level (P>0.05). The hemodynamic indexes were significantly changed by propranolol.Conclusion: Betaglucin has protective effects on myocardial tissue during MI in rats and dogs and has no influence on hemodynamic parameters at a therapeutic dose. The increase in coronary artery blood flow induced by betaglucin might be beneficial in the treat-ment of patients with MI.

  15. Prognostic value of myocardial sympathetic activity in patients with asymptomatic myocardial infarction

    International Nuclear Information System (INIS)

    To clarify the significance of myocardial sympathetic activity in patients with asymptomatic myocardial infarction (MI), we performed 123I-metaiodobenzyl-guanidine (MIBG) and 201Tl imaging at rest. We calculated the ratio of cardiac uptake of the isotope to the total injected dose (%Uptake), percent washout of MIBG over 3 hours and the Uptake Ratio (UR, %Uptake of MIBG divided by %Uptake of 201Tl). We compared these indices with clinical findings, exercise stress-rest myocardial perfusion imaging with 99Tc-methoxy-2-isobutyl isonitrile, coronary angiography, echocardiography and neurohumoral findings. During the follow-up period of 19.9±10.3 months in 32 patients, events (heart failure or cardiac death) developed in 10 (31%). In univariate analysis, diabetes mellitus, atrial fibrillation, left ventricular end-diastolic dimension (LVDd) greater than 54 mm, and the %Uptake of MIBG and UR differed significantly between event and event-free groups. Cox proportional hazard model showed that the UR was a predictor of events (p=0.0007). In patients with UR less than 0.58, the relative risk of events was 19.1 times greater than in patients with an UR greater than 0.58. UR was closely correlated to LVDd (r=-0.578, p=0.01) suggesting that myocardial sympathetic activity is related to LV remodeling after MI. MIBG imaging provides important information regarding the prognosis and the pathophysiologic process of asymptomatic MI. (author)

  16. Immunoscintigraphy for detecting acute myocardial infarction without electrocardiographic changes.

    OpenAIRE

    Jain, D; Lahiri, A; Raftery, E B

    1990-01-01

    OBJECTIVE--To establish whether immunoscintigraphy with antibody to myosin may detect acute myocardial infarction without electrocardiographic changes. DESIGN--Prospective study of patients with suspected acute myocardial infarction or unstable angina with cardiac imaging with 111indium myosin antibody, estimation of cardiac enzyme concentrations, electrocardiography, 201thallium imaging, and radionuclide ventriculography. SETTING--Coronary care unit in a district general hospital. PATIENTS--...

  17. Nonfasting glucose, ischemic heart disease, and myocardial infarction

    DEFF Research Database (Denmark)

    Benn, Marianne; Tybjaerg-Hansen, Anne; McCarthy, Mark I;

    2012-01-01

    The purpose of this study was to test whether elevated nonfasting glucose levels associate with and cause ischemic heart disease (IHD) and myocardial infarction (MI).......The purpose of this study was to test whether elevated nonfasting glucose levels associate with and cause ischemic heart disease (IHD) and myocardial infarction (MI)....

  18. Left ventricular assessment in myocardial infarction - The VALIANT registry

    NARCIS (Netherlands)

    Hernandez, AF; Velazquez, EJ; Solomon, SD; Kilaru, R; Diaz, R; O'Connor, CM; Ertl, G; Maggioni, AP; Rouleau, JL; van Gilst, W; Pfeffer, MA; Califf, RM

    2005-01-01

    Background: How often echocardiography and cardiac catheterization are used to evaluate left ventricular (LV) function in patients with myocardial infarction (MI) and how they are associated with quality of care is unknown. Methods: Patients with MI in the Valsartan in Acute Myocardial Infarction (V

  19. Relation between renal dysfunction and cardiovascular outcomes after myocardial infarction

    DEFF Research Database (Denmark)

    Anavekar, Nagesh S; McMurray, John J V; Velazquez, Eric J;

    2004-01-01

    in Acute Myocardial Infarction Trial (VALIANT), we identified 14,527 patients with acute myocardial infarction complicated by clinical or radiologic signs of heart failure, left ventricular dysfunction, or both, and a documented serum creatinine measurement. Patients were randomly assigned to receive...

  20. Myocardial salvaging effects and mechanisms of metformin in experimental diabetes

    Directory of Open Access Journals (Sweden)

    Manjusha K. Borde

    2016-04-01

    Conclusions: The present study concluded that Metformin at 100 mg/kg demonstrated myocardial salvaging effects in type II diabetic rats challenged with experimental Myocardial infarction. The antioxidant, hypoglycemic, hypolipidemic and anti-inflammatory effects of Metformin may contribute to its beneficial effects. [Int J Basic Clin Pharmacol 2016; 5(2.000: 341-349