1,721,186 research outputs found
Head-to-Head Comparison of Global Longitudinal Strain Measurements among Nine Different Vendors: The EACVI/ASE Inter-Vendor Comparison Study
Full text linkBACKGROUND: This study was planned by the EACVI/ASE/Industry Task Force to Standardize Deformation Imaging to (1) test the variability of speckle-tracking global longitudinal strain (GLS) measurements among different vendors and (2) compare GLS measurement variability with conventional echocardiographic parameters.
METHODS: Sixty-two volunteers were studied using ultrasound systems from seven manufacturers. Each volunteer was examined by the same sonographer on all machines. Inter- and intraobserver variability was determined in a true test-retest setting. Conventional echocardiographic parameters were acquired for comparison. Using the software packages of the respective manufacturer and of two software-only vendors, endocardial GLS was measured because it was the only GLS parameter that could be provided by all manufactures. We compared GLSAV (the average from the three apical views) and GLS4CH (measured in the four-chamber view) measurements among vendors and with the conventional echocardiographic parameters.
RESULTS: Absolute values of GLSAV ranged from 18.0% to 21.5%, while GLS4CH ranged from 17.9% to 21.4%. The absolute difference between vendors for GLSAV was up to 3.7% strain units (P < .001). The interobserver relative mean errors were 5.4% to 8.6% for GLSAV and 6.2% to 11.0% for GLS4CH, while the intraobserver relative mean errors were 4.9% to 7.3% and 7.2% to 11.3%, respectively. These errors were lower than for left ventricular ejection fraction and most other conventional echocardiographic parameters.
CONCLUSION: Reproducibility of GLS measurements was good and in many cases superior to conventional echocardiographic measurements. The small but statistically significant variation among vendors should be considered in performing serial studies and reflects a reference point for ongoing standardization efforts
Comparison of Radio Frequency vs beamformed ultrasound data for infarct classification with CNNs
No full textUltrasound is the most practical, cost-effective and patient-friendly clinical imaging modality. However, Computed Tomography and Magnetic Resonance Imaging outperform echography when texture or tissue characterization is clinically required. As AI-methodologies could help resolve this, a Deep Learning algorithm was applied to classify localized infarcted tissue from static ultrasound recordings.This work was in the context of the International Training Network project called MArie Curie Intelligent UltraSound (MARCIUS). The MARCIUS project has received funding
from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 860745
Ultraschallbasierte Messung der Myokardfunktion bei Patienten mit fortgeschrittener Aortenklappenstenose – vor und nach Klappenersatzoperation
Full text linkBackground and Objectives In Europe and North America, aortic stenosis has become the most frequent valvular heart disease and the most frequent cardiovascular disease after hypertension and coronary artery disease. Modern echocardiography is the most important non-invasive tool to detect and quantify the severity of aortic stenosis. However, regional myocardial function has rarely been described so far. Right after aortic valve replacement afterload decreases but left ventricular hypertrophy remains. The influence of left ventricular geometry on myocardial function as well as the impact of remodeling after valve replacement are not fully understood. The aim of this study is to explore regional systolic and diastolic function of patients with left ventricular hypertrophy due to aortic valve stenosis using doppler velocity and deformation indices as well as conventional echocardiography parameters und their changes early and later after aortic valve replacement, in order to discuss the usefulness of this method to describe adaptive myocardial function and build the base to find new clinical ways of treatment. Methods 33 patients with severe AS were examined before, as well as one week and six months after aortic valve replacement. Beside a standard echocardiogram tissue Doppler data were acquired from an apical four-, three- and two-chamber view using a Vivid 7 scanner (GE Vingmed, Norway) in TVI mode. Data were digitally stored and post-processed off-line using Echo Pac PC software (GE Vingmed, Horten, Norway) and Matlab (Mathworks Inc., Massachusetts, USA)– based research software (TVA, JU Voigt, Leuven, Belgium). Segmental systolic and diastolic velocity and deformation parameters were measured and compared to conventional echocardiographic parameters and left ventricular geometry. The measurements were compared to 17 healthy volunteers. Results Despite normal global left ventricular function, myocardial Doppler based indices of regional systolic and diastolic function were impaired. Furthermore we detected regional differences and variable regional changes after valve replacement. Compared to healthy subjects we found lower longitudinal shortening and shortening rates. After valve replacement systolic strain rate improved immediately. Systolic strain didn’t change right after operation but increased after six month in concordance with the reduction of left ventricular hypertrophy. Medial and basal segments were more impaired than apical ones. In addition, also diastolic function improved after aortic valve replacement. Conclusions In contrast to conventional echocardiographic parameters which are traditionally used to evaluate overall function of the heart, Doppler myocardial indices detect subtle regional changes earlier and are able to describe function changes after valve replacement. Despite normal ejection fraction, regional deformation of the hypertrophic left ventricle was impaired. Left ventricular remodeling resulted in inhomogeneous changes in regional systolic and diastolic myocardial function. We hypothesize, that the ability of Doppler myocardial imaging to detect subtle changes in regional function could improve diagnosis and follow up of patients with aortic stenosis.Hintergrund und Ziele Die Aortenklappenstenose ist inzwischen die häufigste Herzklappenerkrankung in Europa und Nord Amerika ist zudem nach der arteriellen Hypertonie und der koronaren Herzkrankheit die häufigste Erkrankung des kardiovaskulären Systems. Die moderne Echokardiographie ist die wichtigste nichtinvasive Methode eine Aortenklappenstenose zu detektieren und zu quantifizieren. Die regionale Funktion wurde dabei nur wenig beschrieben. Nach Aortenklappenersatz sinkt unmittelbar die Nachlast, jedoch bleibt die vorhandene Hypertrophie zunächst bestehen. Das Verhältnis von linksventrikulärer Geometrie und Herzfunktion sowie die Auswirkungen des Remodellings unmittelbar nach Aortenklappenersatz sind wenig erforscht. Ziel dieser Arbeit ist es, die regionale systolische und diastolische Funktion bei Patienten mit linksventrikulärer Hypertrophie mit Hilfe von Gewebedoppler und Verformungsanalysen herauszuarbeiten und deren Änderungen nach Aortenklappenersatz zu beschreiben, um Rückschlüsse auf myokardiale Anpassungsvorgänge zu ziehen und so eine Basis für eine bessere prognostische Beurteilung von Patienten mit Aortenklappenstenose zu finden. Bestenfalls können neue Parameter gefunden werden die es ermöglichen, gefährdete Patienten ohne wegweisende Symptomatik zu detektieren. Material und Methoden Wir untersuchten 33 Patienten mit fortgeschrittener Aortenklappenstenose vor, sowie eine Woche und sechs Monate nach Aortenklappenersatz. Neben der echokardiographischen Standarduntersuchung zeichneten wir Gewebedopplerdaten des apikalen Vier-, Drei- und Zweikammerblicks auf. Hierfür verwendeten wir ein Vivid 7 Ultraschallgerät (GE Vingmed Ultrasound, Horten, Norwegen) im TVI Modus. Die aufgenommenen Datensätze wurden digital gespeichert und anschließend off-line mit Hilfe der Software EchoPac PC (GE Vingmed, Norwegen) und dem Matlab (Mathworks Inc., Massachusetts, USA)– basierten Kurvenanalyse-Programm TVA (JU Voigt, Leuven, Belgien) analysiert. Die so gewonnenen regionalen systolischen und diastolischen Geschwindigkeits- und Verformungswerte wurden zu den echokardiographischen Parametern und zur linksventrikulären Geometrie in Beziehung gesetzt. Siebzehn ältere Probanden und Studenten bildeten eine gesunde Vergleichsgruppe. Ergebnisse und Beobachtungen Trotz guter linksventrikulärer Globalfunktion konnten wir mittels Gewebedoppler Echokardiographie bei den Patienten mit Aortenklappenstenose systolische und diastolische Funktionseinbußen nachweisen. Zudem zeigten sich regionale Unterschiede der Myokardfunktion. Auch im Verlauf nach Klappenersatzoperation beobachteten wir regionale Änderungen unterschiedlichen Ausmaßes. So war bei den Patienten präoperativ sowohl die systolische Verkürzung als auch die Verkürzungsrate signifikant niedriger als bei den Probanden. Im Verlauf verbesserte sich sofort nach dem AKE die systolische Verkürzungsrate. Das regionale Verkürzungsvermögen verbesserte sich jedoch erst nach sechs Monaten signifikant zusammen mit der Reduktion der hypertrophischen Veränderungen. Die medialen und basalen Segmente waren hierbei stärker beeinträchtigt als die apikalen. Auch die diastolische Funktion verbesserte sich nach dem Aortenklappenersatz. Praktische Schlussfolgerungen Im Gegensatz zu konventionellen globalen echokardiographischen Funktionsparametern vermögen regionale Analysen mittels Gewebedoppler- Echokardiographie bereits früher Veränderungen in der Myokardfunktion aufzuzeigen und scheinen auch im Verlauf den globalen Parametern überlegen zu sein. Trotz normaler Ejektionsfraktion war die regionale Verformung des hypertrophen linken Ventrikels bereits vermindert. Die veränderte Herzgeometrie beeinflusst dabei die regionale systolische und diastolische Myokardfunktion in unterschiedlichem Ausmaß. Die Fähigkeit Gewebedoppler-basierter Verformungsmessungen, subtile Veränderungen der regionalen Myokardfunktion zu detektieren, könnte in Zukunft zur Verbesserung der Diagnostik und Prognoseabschätzung bei Patienten mit Aortenklappenstenose eingesetzt werden
Die Auswirkungen von Erregungsleitungsstörungen auf die regionale Myokardfunktion des linken und rechten Ventrikels
Full text linkAbstract Background, Aims CRT has become an established therapeutic option in patients with heart failure and conduction delays. Despite the use of acknowledged selection criteria, 20-30% of eligible patients do not respond favourably to cardiac resynchronization therapy (CRT). Current selection criteria may account for that. Several echocardiographic, Doppler myocardial imaging based parameters have been proposed in the past, but failed to prove added diagnostic value. In this study we aimed at a detailed analysis of regional LV function in normal hearts and different conduction abnormalities in order to derive new, better parameter to easily describe mechanical LV asynchrony which could potentially be used to guide CRT. Methods 19 healthy volunteers (NORM) and 48 patients with bundle branch blocks (12 RBBB (RSB), 25 non-ischemic LBBB (LSB), 11 ischemic LBBB (LSBi), standard echocardiography and Doppler myocardial imaging. Digitally stored Data were analyzed offline. Segmental velocity, deformation and timing parameters were extracted to characterize left ventricular asynchrony. Apical transverse motion (ATB), a new approach to describe LV asynchrony in one, easy parameter was validated. Results NORM and RSB patients did not differ significantly regarding regional and global LV function. LSB and LSBi patients had a significantly impaired ejection fraction compared to NORM and RSB (23% und 23% vs. 62% und 63%, p<0.001). Longitudinal systolic shortening was reduced (–8% LSB vs. NORM -15%, P<0,0001). Begin of myocardial shortening was (tBegV 117ms vs. NORM 33ms, P<0,0001) and asynchronous with the septum being earliest and the posterior walls being latest. This disturbed temporal sequence of contraction results in parts of the myocardium contracting inefficiently outside ejection time. Lateral walls contribute most to the ejection work (Lat 61% vs. Sep 42%, P= P=0,0078). Characterizing the asynchrony in our study groups by using published, Doppler-based asynchrony parameters revealed inconsistent results. Deformation imaging and the new parameter ATB could well characterize LV-mechanics (ATB 4,2 mm, vs. NORM 1,8 mm, P<0,0001). Conclusion Conduction abnormalities result in characteristic changes in regional and global myocardial function which can be characterized by ATB. ATB is a potential new parameter to guide CRT.Hintergrund und Ziele Die kardiale Resynchronisation durch biventrikuläre Stimulation gilt inzwischen als etablierte Therapieoption bei Patienten mit schwerer Herzinsuffizienz und Erregungsleitungsstörungen. 20-30% eines bereits selektierten Patientengutes sprechen jedoch nicht auf die kardiale Resynchronisationstherapie (CRT) an. Die bisher anerkannten, ausschließlich auf klinischen Daten, EKG und Ejektionsfraktion beruhenden Selektionskriterien sind daher möglicherweise zu ungenau. Wünschenswert wäre eine Methode zur objektiven Beurteilung der mechanischen Asynchronie. Die Gewebedoppler-Echokardiografie mit ihrer hervorragenden zeitlichen und guten räumlichen Auflösung erscheint diesbezüglich als vielversprechende Technik. Bisherige, Doppler-basierte Parameter zeigten in großen klinischen Studien keinen deutlichen Zusatznutzen. Ziel dieser Studie war daher, aufgrund einer genauen Analyse der Auswirkung von Erregungsleitungsstörungen auf die Mechanik der Ventrikelkontraktion neue Parameter zu finden, die die mechanische Asynchronie besser beschreiben und potenziell zur Patientenselektion bei CRT eingesetzt werden können. Methoden Bei 19 gesunden Probanden (NORM) und 48 Patienten mit Schenkelblock (12 mit Rechtsschenkelblock (RSB), 25 mit nicht-ischämischem Linksschenkelblock (LSB), 11 mit ischämischem LSB (LSBi)) wurde die Herzfunktion mittels Standard- und Gewebedoppler-Echokardiografie untersucht. Aus den digital gespeicherten Datensätzen wurden regionale Funktionsdaten extrahiert und Geschwindigkeits-, Verformungs- und Zeitparameter zur Charakterisierung der Asynchronie des linken Ventrikels analysiert. Darauf aufbauend wurde ein neuer Parameter zur Beschreibung der linksventrikulären mechanischen Asynchronie entwickelt (apikale Transversalbewegung, ATB) und validiert. Ergebnisse und Beobachtungen NORM und RSB Patienten unterschieden sich hinsichtlich der globalen und regionalen linksventrikulären Funktion nicht signifikant. Patienten mit LSB und LSBi hatten jedoch eine signifikant niedrigere Ejektionsfraktion als NORM und RSB Patienten (23% und 23% vs. 62% und 63%, p<0.001). Die longitudinale εET war ebenfalls erniedrigt (–8% LSB vs. NORM -15%, P<0,0001). Der Beginn der regionalen Myokardverkürzung war deutlich zeitverzögert (tBegV 117ms vs. NORM 33ms, P<0,0001) und asynchron, septal beginnend und posterior endend. Durch die gestörte zeitliche Abfolge der regionalen Myokardkontraktion konnten Teile des Myokards nicht zur Ejektion beitragen. Den größten Beitrag zur Auswurfarbeit leisteten laterale Ventrikelwände (εET/εges: Lat 60,8% vs. Sep 42,4%, P=0,0078). Die Quantifizierung der Asynchronie mittels bekannter, dopplerbasierter Parameter ergab widersprüchliche Ergebnisse. Verformungsanalysen sowie der neue Parameter ATB beschreiben die mechanische Asynchronie hingegen gut (ATB 4,2 mm vs. NORM 1,8 mm, P<0,0001). Praktische Schlussfolgerungen Erregungsleitungsstörungen führen zu charakteristischen Veränderungen der globalen und regionalen linksventrikulären Kontraktion. Ihre Charakterisierung mittels ATB ist gut möglich und stellt einen potenziellen Ansatz zur besseren Patientenselektion bei CRT dar
Combinatie van PET/CT en 4D anatomische beeldvorming ter verbetering van de kwantificatie van FDG tracer opname
No full textThe measurement of 18F-Fluorodeoxyglucose (FDG) uptake by positron emission tomography (PET) is a validated and robust way to investigate myocardial glucose metabolism. However, the use of PET imaging for cardiac applications is challenged by:
- the low spatial resolution of the clinical PET scanners, which results in blurring and does not
allow for accurate quantification of very thin or small structures (partial volume effect, PVE)
- the moving nature of the heart and the organs around it.
The contribution of motion to cardiac images can be mitigated with different motion correction techniques. One of the most common and straightforward methods, although not optimal for image quality, is to sort the PET dataset into a set of frames corresponding to the different phases of the periodic motion (gating), and then independently reconstruct and use each of them. The issue related to PVE has also been previously addressed. Among all available techniques, coupling PET data with information coming from imaging modalities that provide valuable anatomical information at higher resolution, like CT or MR, during the PET reconstruction (partial volume correction, PVC) has been proven promising in brain. The application of such a partial volume correction technique to a measured PET dataset relies on a good alignment between the anatomical image and the low-resolution PET. Hence, any source of misregistration needs to be avoided. In this scenario, PET attenuation correction might play a role in compromising the registration results, and subsequent PVC.
The aim of this project is to develop, test and validate image processing algorithms that enable the motion compensation and anatomy-guided partial volume correction of cardiac FDG-PET images, in order to provide a more accurate extraction of parameters representing the regional energy consumption in the left ventricle (LV). The study of the relationship between the oxidative metabolism (as a measure of energy consumption) and the regional myocardial deformation as measured with echo, MR or other functional measurements, will ultimately help to better select patients for, and foresee the impact of, cardiac resynchronization therapy in the clinical practice.status: Publishe
Multimodale moleculaire beeldvorming van ischemische hartziekte en hartfalen
No full textDuring the last decades important technological advances in nuclear imaging, represented by single-photon emission computed tomography (SPECT) and positron emission tomography (PET), strengthened its position in the field of non-invasive cardiac imaging and expanded its opportunities for the evaluation of patients with cardiovascular diseases. This PhD project was intended to give an insight in some of the novel opportunities of nuclear cardiology to assess perfusion and metabolism that can assist in the diagnosis of CAD and therapy guidance in the context of heart failure (HF).
One of the research aims of this PhD project was to explore how the assessment of perfusion and glucose metabolism, with 13N-NH3 and 18F-FDG PET, respectively, can help to unravel the pathophysiology of left ventricular (LV) remodelling in cardiac-resynchronization therapy (CRT) candidates and whether PET can help to reliably guide the necessity of CRT implantation in HF patients.
A second research focus of this PhD project was on the recently introduced novel cardiac dedicated cadmium-zinc-telluride (CZT) SPECT cameras, that for the first time offered an opportunity to quantify myocardial perfusion with SPECT, providing a great potential for the improvement of management of patients with CAD. Furthermore, acknowledging the disadvantages of clinically available SPECT perfusion tracers, we renewed our interest in 99mTc-teboroxime - a perfusion tracer with more favourable characteristics, that for a long time was withdrawn from the market due to incompatibility of its fast kinetics with the slow conventional SPECT cameras. In this research project we investigated if the fast kinetics of 99mTc-teboroxime could be an advantage for the novel SPECT CZT camera and evaluated its performance to quantify myocardial perfusion.status: Publishe
Klinische Relevanz und untere Grenze der Normalität von neuer linksventrikulärer, rechtsventrikulärer und linksatrialer Funktionsparameter mittels Speckle-Tracking-Echokardiographie
No full textThe findings of these studies analyzing large cohorts of healthy subjects and patients with CV diseases and risk factors have highlighted and demonstrated the potential usefulness and clinical relevance of new functional and myocardial parameters such as LV strain, RV strain, and LA strain. In addition, these studies have provided the lower limit of normality of these new myocardial parameters, which could be of pivotal importance in determining normal or abnormal cardiac function using these new parameters. Nonetheless, further studies should validate these findings and expert consensus should recommend these new myocardial parameters before introducing these new LV, RV, and LA functional analyses into clinical practice
Tricuspidalisklep Insufficiëntie bij Druk- of Volumebelasting van het Rechter Ventrikel: Epidemiologie, Determinanten en Behandeling.
No full textstatus: Publishe
Layer-Specific Segmental Longitudinal Strain Measurements: Capability of Detecting Myocardial Scar and Differences in Feasibility, Accuracy, and Reproducibility, Among Four Vendors A Report From the EACVI-ASE Strain Standardization Task Force
No full textBACKGROUND:
Segmental longitudinal strain (SLS) is reported to be vendor specific. Despite standardization efforts, vendors still use different myocardial layers for strain measurements. It is unclear, however, which layer is the most favorable for clinical purposes. Therefore, in this study we evaluated the reproducibility, accuracy, and scar detection ability of SLS measurements from different myocardial layers.
METHODS:
In data sets of 58 patients with prior myocardial infarction and five healthy volunteers, we measured the intervendor bias, the relative test-retest variability, and scar discrimination ability of endocardial and midwall SLS, using software packages from four different companies (GE, Siemens, Toshiba, and TomTec). Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition.
RESULTS:
Variability of SLS measurements was significant among the vendors for both midwall and endocardium. In addition, relative errors of SLS measurements varied considerably among vendors (P < .001 for both layers). Comparisons of test-retest errors from different layers for individual vendors did not show any significant differences. Regardless of the vendor, both endocardial and midwall strain values were decreased in scarred segments. Endocardial to midwall ratio of strain measurements showed no difference between scar-free and scarred segments. Endocardial and midwall strain parameters showed no significant difference in scar detection capability.
CONCLUSIONS:
Layer-specific SLS measurements vary significantly among vendors. Endocardial and midwall SLS measurements have a high yet comparable test-retest variability. Combining layer-specific SLS measurements does not provide additional information for detection of regional functional abnormalities. Our results do not provide evidence to favor the use of one myocardial layer over another
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