Search results for "Compaction"
showing 10 items of 105 documents
ICD implantation in noncompaction of the left ventricular myocardium: a case report
2009
Isolated noncompaction of the ventricular myocardium (INVM) is an uncommon cardiomyopathy characterized by the persistence of fetal myocardium with prominent trabecular meshwork and deep intertrabecular recesses, often associated with systolic dysfunction and ventricular dilatation. A 23-year-old man from Burkina Faso was referred to our operative unit with a diagnosis of INVM, made with echocardiogram and magnetic resonance imaging and nonsustained ventricular tachycardia. The literature reports the incidence of malignant ventricular arrhythmias in as many as 47% of the patients and sudden cardiac death in almost 50% of them and this supported our decision to perform implantable cardiovert…
Non-compact myocardium assessment by cardiac magnetic resonance: dependence on image analysis method
2018
To compare image analysis methods for the assessment of left ventricle non-compaction from cardiac magnetic resonance (CMR) imaging. CMR images were analyzed in 20 patients and 10 normal subjects. A reference model of the MR signal was introduced and validated based on image data. Non-compact (NC) myocardium size and distribution were assessed by tracing a single, continuous contour delimiting trabeculated region (Jacquier) or by one-by-one selection of trabeculae (Grothoff). The global non-compact/compact (NC/C) ratio, the NC mass, and the segmental NC/C ratio were assessed. Results were compared with the reference model. A significant difference between Grothoff and Jacquier approaches in…
The planimetric Grothoff's criteria by cardiac magnetic resonance can improve the specificity of left ventricular non-compaction diagnosis in thalass…
2020
We differentiated the left ventricle non-compaction (LVNC) from hypertrabeculated myocardium due to a negative remodeling in thalassemia intermedia (TI) patients applying linear and planimetric criteria and comparing the cardiovascular magnetic resonance (CMR) findings. CMR images were analyzed in 181 TI patients enrolled in the Myocardial Iron Overload in Thalassemia Network and 27 patients with proved LVNC diagnosis. The CMR diagnostic criteria applied in TI patients were: a modified linear CMR Petersen’s criterion based on a more restrictive ratio of diastolic NC/C > 2.5 at segmental level and the combination of planimetric Grothoff’s criteria (percentage of trabeculated LV myocardial…
Evaluation of diastolic function by the Tissue doppler in children affected by non- compaction
2007
The Tissue doppler analysis is a new echocardiographic approach to evaluate the diastolic function. In this report we performed a Tissue doppler analysis in a series of 15 children affected by non-compaction. The bidimensional echo-cardiogram showed a systolic function which was reduced only in 8 patients. Alterations of the diastolic function were founded in 7 patients: in 2 cases, a reduction of the E tissue wave was present in all segments. In 3 patients the diastolic dysfunction was limited to apical and lateral segments. In the last 2 children a reduction of the E wave interested only the apical segments. There was a strong correlation between systolic and diastolic dysfunction: in fac…
Speckle myocardial imaging modalities for early detection of myocardial impairment in isolated left ventricular non-compaction
2009
Objective To examine the hypothesis that speckle myocardial imaging (SMI) modalities, including longitudinal, radial and circumferential systolic (s) and diastolic (d) myocardial velocity imaging, displacement (D), strain rate (SR) and strain (S), as well as left ventricular (LV) rotation/torsion are sensitive for detecting early myocardial dysfunction in isolated LV non-compaction (iLVNC). Design and results Twenty patients with iLVNC diagnosed by cardiac magnetic resonance (15) or echocardiography (5) were included. Patients were divided into two groups: ejection fraction (EF)>50% (n=10) and EF≤50% (n=10). Standard measures of systolic and diastolic function including pulsed wave tissue D…
An investigation of the mechanical properties of rubber modified asphalt mixtures using a modified dry process
2017
Incorporating recycling tyres into asphalt mixtures contributes to solving a serious environmental problem as well as the potential of improving the mechanical performance of asphalt mixtures. The recycled tyre rubber is added by two technologies known as the dry process (when rubber particles are treated as an aggregate modifier) and the wet process (when rubber particles are treated as a binder modifier). Although, the dry process is easier and requires minimal or no modification in the asphalt plant, the inconsistency in field performance makes the dry process not widely used. The main reason for this is believed to be the lack of interaction between the rubber particles and binder. In o…
Influences of atomization process and precursor material on the compaction mechanisms and metallurgical properties of parts developed by HIP
2022
Hot Isostatic pressing process is based on the densification of metals powders to near net shape parts with higher mechanicals properties than forged chemical equivalent. The precursor material can influence the parts properties. Thus the aims of this these is to understand the influence of the powder properties on the HIP parts. The particles characterization and the elements and compound monitoring during the HIP cycle allowed to understand the different oxidations phenomenons and their impact on the mechanical properties of parts. The comparison of differents powders batches with identical particles size repartition or identical chemical composition showed that the chemical composition a…
Bitumen stabilized ballast: a potential solution for railway track-bed
2016
Railway ballast degradation under dynamic loads progressively leads to loss of mechanical performance and geometry of the track, so that maintenance interventions are frequently needed. In order to system- atically avoid this issue, recently solutions have been proposed to reinforce track-bed by using polyur- ethane and/or resins as well as asphalt layers among others. Nonetheless, their main limitations are related to the high initial cost and low productivity. To cope with these limitations, in this study, bitumen stabilized ballast (BSB) is proposed as a new solu- tion for ballast stabilization. This method aims at improving durability and reducing settlement by mod- ifying both stiffnes…
Phenotype/Genotype Relationship in Left Ventricular Noncompaction: Ion Channel Gene Mutations Are Associated With Preserved Left Ventricular Systolic…
2021
International audience; Background: Few data exist concerning genotype-phenotype relationships in left ventricular noncompaction (LVNC).Methods and results: From a multicenter French Registry, we report the genetic and clinical spectrum of 95 patients with LVNC, and their genotype-phenotype relationship. Among the 95 LVNC, 45 had at least 1 mutation, including 14 cases of mutation in ion channel genes. In a complementary analysis including 16 additional patients with ion channel gene mutations, for a total of 30 patients with ion channel gene mutation, we found that those patients had higher median LV ejection fraction (60% vs 40%; P < .001) and more biventricular noncompaction (53.1% vs 18…
Preparation of synthetic sandstones with variable cementation for studying the physical properties of granular rocks
1997
In this article, we report a new set of procedures to fabricate synthetic analogues of granular rocks. These procedures permit accurate control of the most important structural parameters (i.e., grain size, porosity, cement content). We were thus able to prepare two varieties of synthetic sandstones in which only the cement content significantly varied. Our procedures were also particularly successful in producing materials that were very similar to natural rocks. To demonstrate this similarity, we compared the microstructure, the mechanical properties (i.e., strength, elastic moduli) and the mechanical behaviour (i.e., brittle or ductile) of the synthetic materials to those of various natu…