Die technologische Entwicklung im Bereich der Echokardiographie hat in der letzten Dekade neue Methoden zur objektiven Erfassung der regionalen linksventrikulären Wandbewegung ermöglicht. Speckle Tracking erfasst die myokardiale Deformation durch die Positionsänderung einzelner Bildpunkte von einem Bild des analysierten Datensatzes zum nächsten. Diese Methode ist dem Gewebedoppler überlegen, insbesondere wegen ihrer Unabhängigkeit vom Anlotungswinkel. Zwei-dimensionale (2D) Speckle Tracking Analysen wurden für die klinische Praxis validiert. Die drei-dimensionale (3D) Echokardiographie erlaubt inzwischen Speckle Tracking Analysen von 3D Datensätzen, welche jedoch für die klinische Praxis noch nicht ausreichend validiert sind. Bei Patienten mit normaler regionaler linksventrikulärer Wandbewegung (N=37), sowie bei Patienten mit ischämie-bedingten Wandbewegungsstörungen (N=18) wurden 3D und 2D Speckle Tracking Analysen durchgeführt. Die Vergleichbarkeit der beiden Methoden hinschtlich der Quantifizierung von normalen und pathologischen Wandbewegungsmustern wurde anhand dieser Messungen geprüft. Des weiteren wurde der Einfluss der Bildrate und Bildqualität drei-dimensionaler Datensätze auf die Vergleichbarkeit beider Methoden analysiert. Es zeigte sich eine gute Vergleichbarkeit des 2D und 3D Speckle Tracking in der Diagnostik eingeschränkter linksventrikulärer systolischer Funktion, sowie in der Lokalisationsdiagnostik umschriebener Wandbewegungsstörungen. 2D und 3D Speckle Tracking sind jedoch noch nicht als gleichwertige Methoden anzusehen. Die Bildqualität, generell bei beiden Modalitäten - jedoch speziell bei 3D Datensätzen, sowie die Bildrate der 3D Datensätze zeigen signifikante Einflüsse auf die 3D Strain Analysen. Eine korrekte Standardisierung der analysierten Aufnahmen und eine optimale Bildqualität sind wichtige Faktoren, die die Zuverlässigkeit des 2D und 3D Speckle Trackings bestimmen.

Freehand 3-D ultrasound (US) using a 2-D US probe has the advantage over conventional 3-D probes of being able to collect arbitrary 3-D volumes at a lower cost. Traditionally, generating a volume requires external tracking to record the US probe position. An alternative means of tracking the US probe position is through speckle tracking. Ultrasound imaging has the advantage that the speckle inherent in all images contains relative position information due to the decorrelation of speckle over distance. However, tracking the position of US images using speckle information alone suffers from drifts caused by tissue inconsistencies and overall lack of accuracy. This thesis presents two novel methods of improving the accuracy of speckle-tracked 3-D US through the use of sensor fusion. The first method fuses the speckle-tracked US positions with those measured by an electromagnetic (EM) tracker. Measurements are combined using an unscented Kalman filter (UKF). The fusion is able to reduce drift errors as well as to eliminate high-frequency jitter noise from the EM tracker positions. Such fusion produces a smooth and accurate 3-D reconstruction superior to those using the EM tracker alone. The second method involves the registration of speckle-tracked 3-D US volumes to preoperative CT volumes. We regard registration combined with speckle tracking as a form of sensor fusion. In this case, speckle tracking is used in the registration to generate an initial position for each US image. To improve the accuracy of the US-to-CT registration, the US volume is registered to the CT volume by creating individual US "sub-volumes", each consisting of a small section of the entire US volume. The registration proceeds from the beginning of the US volume to the end, registering every sub-volume. The work is validated through spine phantoms created from clinical patient CT data as well as an animal study using a lamb cadaver. Using this technique, we are able to successfully register a speckle-tracked US volume to a CT volume with excellent accuracy. As a by-product of accurate registration, any drift from the speckle tracking is eliminated and the freehand 3-D US volume is improved. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-10-19 00:10:25.717

This thesis work provides a new way to detect and track the displacement of flexor tendons within the human arm, using a non-invasive, ultrasound-based, speckle tracking technique. By tracking the tendons in the arm, it provides a way to monitor a person’s intention to move their hands and fingers. This has application to hand prosthetic control, as well as tendon injury assessment, which has significant contributions to the medical and rehabilitation community. The system works by capturing and processing a sequence of B-scan ultrasound images, to detect and track the flexor tendon motion (excursion) in the wrist, as the user flexes their muscles. Given the biomechanics of the hand, tendon displacement is correlated to the user’s intention to move their finger. Several speckle tracking techniques using B-scan ultrasound image sequences are developed in this work, including: auto-location of the tendon, a stationary ROI (region of interest), and novel use of similarity measures such as FT (Fisher Tippett), and hybrid methods. As well, work is done to investigate various speckle tracking parameters, and their effects on tracking accuracy. The different speckle tracking techniques are developed using data obtained from cadaver hands, and human volunteers undergoing regular surgery. The tracking techniques are compared in terms of successfully detecting the tendon, accurately tracking tendon displacement, successfully tracking multiple tendons, successfully detecting and tracking the onset of low tendon displacement, and computational efficiency of the algorithms. Another major aspect of this work is the design of a novel quad-array transducer that can collect image sequences from up to four tendons simultaneously. This transducer is instrumental to the motivation for controlling an advanced prosthesis. As well, specialized hardware is designed for the cadaver-based studies. Overall, this thesis successfully demonstrated the proposed tracking algorithms and newly designed hardware, for tracking the displacement of single and multiple flexor tendons. It has provided several important contributions to the field. / Graduate / 0548 / 0986 / 0760

Hälsenan har en viktig roll för motoriken av underbenet samt rörelse vid gång och löpning. I och med detta sker det en stor belastning på hälsenan vid gång och löpning vilket kan leda till bristningar och skador på senan. Dessa bristningar kan ske när hälsenan deformeras i samband med fysisk aktivitet. Deformation av hälsenan är differensen mellan relativ displacement i senan och är ett viktigt koncept inom förståelsen om hälseneskadors etiologi. Syftet med detta examensarbete var att öka kunskapen om displacement i hälsenan och hur det skiljer sig vid habituell löpning med olika löparskor inklusive barfotalöpning. Vidare felsöktes en speckle tracking-algoritm som lägger grund för analysen av displacement i hälsenan. Arbetet är en utökning på ett pågående forskningssamarbete mellan KTH, GIH och KI. Det första steget i arbetet var att MATLAB-programmet för speckle tracking-algoritmen felsöktes och korrigerades. Detta gjordes genom att ändra initiala startvärden i algoritmen såsom centralfrekvensen och värdet för hastigheten av displacement i hälsenan. Efter att hastigheten valts till 2 cm/s fungerade algoritmen felfritt. Nästa steg var att exekvera programmet på den ultraljudsdata för hälsenan som tidigare samlats in från forskningssamarbetet. Algoritmen kördes för tre studiepersoner för habituell löpstil med tre olika löparskor samt barfota. Detta resulterade i att medelvärdeskurvor för ytlig och djup displacement i hälsenan kunde plottas där dess minimum- och maximumvärden kunde jämföras. Efter att differensen för minimum- och maximumvärdet för ytlig och djup displacement hade jämförts mellan samtliga löparskor samt barfota, kunde följande konstateras. Löpning med traditionella skor medförde högst djup displacement följt av skor med kolfibersula, minimalistiska skor och barfotalöpning. Den sko som medförde högst ytlig displacement var skor med kolfibersula följt av traditionella skor, minimalistiska skor samt löpning barfota. Jämförelsen har ej baserats på någon statistisk grund då endast tre studiepersoner analyserades. Detta medför en viss osäkerhet gällande vilken skotyp som medför högst respektive lägst displacement. Bortsätt från denna osäkerhet kan det konstateras att resultat från tidigare studier tyder på liknande insikter. / The Achilles tendon plays a crucial role in the motor function of the lower leg, as well as in the motion involved in walking and running. As a result, the Achilles tendon undergoes significant stress during walking and running, which can lead to tears and injuries to the tendon. These tears can occur when the Achilles tendon is deformed associated with physical activity. The deformation of the Achilles tendon is the difference between the relative displacement in the tendon and is an important concept in understanding the etiology of Achilles tendon injuries. The purpose of this thesis is to increase knowledge about the displacement in the Achilles tendon and how it differs during habitual running with different running shoes, including barefoot running. Furthermore, a speckle tracking algorithm that forms the basis for analyzing the displacement in the Achilles tendon is debugged. The work is an extension of an ongoing research collaboration between KTH, GIH, and KI. The first step in the work was to debug and correct the MATLAB program for the speckle tracking algorithm. This was done by changing initial starting values in the algorithm such as the central frequency and the value for the speed of displacement in the Achilles tendon. After choosing a speed of 2 cm/s, the algorithm worked flawlessly. The next step was to execute the program on the ultrasound data for the Achilles tendon previously collected from the research collaboration. The algorithm was run for test subjects 17, 18, and 21 for habitual running style with three different running shoes and barefoot. This resulted in mean value curves for superficial and deep displacement in the Achilles tendon being plotted, with their minimum and maximum values being compared. After comparing the difference between the minimum and maximum values of superficial and deep displacement across all running shoes as well as barefoot, the following observations were made. Running with traditional shoes caused the highest deep displacement, followed by shoes with carbon fiber soles, minimalist shoes, and barefoot running. The shoe that caused the highest superficial displacement was shoes with carbon fiber soles, followed by traditional shoes, minimalist shoes, and running barefoot. The comparison was not based on any statistical basis since only three test subjects were analyzed. This implies some uncertainty as to which type of shoe causes the highest and lowest displacement. Aside from this uncertainty, it can be noted that the results from previous studies have findings that suggest similar insights.

Die technologische Entwicklung im Bereich der Echokardiographie hat in der letzten Dekade neue Methoden zur objektiven Erfassung der regionalen linksventrikulären Wandbewegung ermöglicht. Speckle Tracking erfasst die myokardiale Deformation durch die Positionsänderung einzelner Bildpunkte von einem Bild des analysierten Datensatzes zum nächsten. Diese Methode ist dem Gewebedoppler überlegen, insbesondere wegen ihrer Unabhängigkeit vom Anlotungswinkel. Zwei-dimensionale (2D) Speckle Tracking Analysen wurden für die klinische Praxis validiert. Die drei-dimensionale (3D) Echokardiographie erlaubt inzwischen Speckle Tracking Analysen von 3D Datensätzen, welche jedoch für die klinische Praxis noch nicht ausreichend validiert sind. Bei Patienten mit normaler regionaler linksventrikulärer Wandbewegung (N=37), sowie bei Patienten mit ischämie-bedingten Wandbewegungsstörungen (N=18) wurden 3D und 2D Speckle Tracking Analysen durchgeführt. Die Vergleichbarkeit der beiden Methoden hinschtlich der Quantifizierung von normalen und pathologischen Wandbewegungsmustern wurde anhand dieser Messungen geprüft. Des weiteren wurde der Einfluss der Bildrate und Bildqualität drei-dimensionaler Datensätze auf die Vergleichbarkeit beider Methoden analysiert. Es zeigte sich eine gute Vergleichbarkeit des 2D und 3D Speckle Tracking in der Diagnostik eingeschränkter linksventrikulärer systolischer Funktion, sowie in der Lokalisationsdiagnostik umschriebener Wandbewegungsstörungen. 2D und 3D Speckle Tracking sind jedoch noch nicht als gleichwertige Methoden anzusehen. Die Bildqualität, generell bei beiden Modalitäten - jedoch speziell bei 3D Datensätzen, sowie die Bildrate der 3D Datensätze zeigen signifikante Einflüsse auf die 3D Strain Analysen. Eine korrekte Standardisierung der analysierten Aufnahmen und eine optimale Bildqualität sind wichtige Faktoren, die die Zuverlässigkeit des 2D und 3D Speckle Trackings bestimmen.

Orientador: Aparecido Antonio Camacho / Resumo: O objetivo do presente estudo foi investigar a função miocárdica pela técnica de ecocardiografia bidimensional speckle tracking (2D STE) em pacientes submetidos à procedimentos anestésico prolongado, com a intenção de se detectar possível disfunção sistólica. Inicialmente para se determinar o intervalo normal da função sistólica na espécie, foram utilizados 31 coelhos da raça Nova Zelândia, adultos, hígidos, machos, com peso médio de 4,0 ± 0,53 kg, nos quais foram obtidos os índices sistólicos radiais como, velocidade rotacional e radial, deslocamento rotacional e radial, strain radial e strain rate radial. Posteriormente, para investigação da função sistólica sob diferentes modalidades ventilatórias, 32 coelhos foram distribuídos, aleatoriamente, em quatro grupos de modalidades ventilatórias diferentes constituídos de 8 animais cada, denominados grupo ventilação ciclada à pressão (GP), grupo ventilação ciclada à pressão associada à PEEP (GPP), grupo ventilação mandatória intermitente sincronizada (GM) e grupo ventilação espontânea (GE). Em todos os grupos, os parâmetros foram mensurados 40 minutos após a indução anestésica (M0) e reavaliados a cada vinte minutos, durante duas horas ininterruptas (M1, M2, M3 e M4). Portanto, o resultado demonstrados na presente investigação cientifica revelam que nenhuma modalidade ventilatória estudada proporcionou um quadro de disfunção sistólica a luz da técnica 2D STE quando foram comparados em cada momento de avaliação anestésica. / Abstract: The aim of this thesis was to investigate the cardiac function of patients undergoing prolonged anesthesia with the use of a two-dimensional speckle tracking (2D STE) technique to detect systolic dysfunction in order to maintain safety during anesthetic procedure. The study was carried out in healthy rabbits because this species is widely used as a model of experimentation for both humans and other animal species. Initially, the normal range of left ventricular radial systolic function was measured, for this purpose, 31 healthy male adults New Zealand rabbits were used, with average weight of 4.0 ± 0.53 kg, from a specialized producer; radial systolic indices were obtained, such as rotational and radial speed, rotational and radial displacement, radial strain and strain rate. Subsequently, 32 rabbits were randomly assigned to four groups of different ventilatory modalities consisting of 8 animals each, referred to as pressure-cycling ventilation group (GP), pressure-cycling ventilatory group associated with PEEP (GPP), synchronized intermittent mandatory ventilation group (GM) and spontaneous ventilation group (GE). In all groups, the parameters were measured 40 minutes after anesthetic induction (M0) and reevaluated every twenty minutes, for two uninterrupted hours (M1, M2, M3 and M4). Therefore, the results demonstrated in the present scientific investigation reveal that no studied ventilatory modality provided a picture of systolic dysfunction in light of the 2D STE techni... (Complete abstract click electronic access below) / Doutor

Advances in the imaging techniques of the heart have fueled the interest in understanding of right heart pathology. Recently, speckle tracking echocardiography has shown to aid in understanding various right heart diseases and better management. Its role is well established in diagnosing right heart failure, pulmonary artery hypertension, arrhythmogenic right ventricular dysplasia and congenital heart disease. We review the basic mechanics of speckle tracking and analyze its role in various right heart conditions.

Orientador: Aparecido Antonio Camacho / Resumo: A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma doença de origem genética, muito prevalente em cães da raça Boxer. Histologicamente ocorre atrofia dos cardiomiócitos do ventrículo direito (VD) e consequente infiltração fibroadiposa, levando ao aparecimento de arritmias ventriculares. Mesmo sendo as alterações miocárdicas microscópicas em sua maioria, estudos recentes têm identificado disfunção contrátil do ventrículo direito, mesmo em estágios iniciais da doença em humanos, tanto por técnicas convencionais de ecocardiografia quanto por técnicas mais avançadas, como no caso do speckle tracking. Por isso, o objetivo deste estudo foi avaliar se há disfunção miocárdica de VD detectável pela ecocardiografia convencional e pela técnica de speckle tracking bidimensional em cães da raça Boxer portadores da CAVD. Para tanto, utilizou-se cães da raça Boxer com idade superior a quatro anos, distribuídos em dois grupos de acordo com o resultado da avaliação Holter (GC: < 50 EVs/24h, n=11 e GD: > 100 EVs/24h, n=11). Os animais foram submetidos a ecocardiografia e avaliou-se diâmetro e comprimento interno do VD em sístole e diástole, encurtamento fracional da área do VD (FAC), excursão sistólica do plano anular da tricúspide (TAPSE), velocidade miocárdica sistólica do ânulo lateral da tricúspide derivada do Doppler tecidual (S’) e deformação (strain) e taxa de deformação (strain rate) longitudinal global da parede livre do VD, derivados da análise por speckle tracking. As... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disease with a high prevalence in Boxer dogs. Histologically, right ventricle (RV) cardiomyocytes’ atrophy occurs, and thus fibrofatty infiltration, triggering ventricular arrhythmias. Although the myocardial changes are mostly microscopic, recent studies in human beings have identified right ventricular systolic dysfunction even in the early stages of ARVC, both by conventional echocardiographic techniques and advanced methods, such as speckle tracking. Therefore, the aim of this study was to investigate if RV myocardial dysfunction is present in Boxers affected by ARVC, evaluated by conventional echocardiography and bidimensional speckle tracking technique. For this purpose, Boxers older than four years were recruited, and based on 24-hour Holter recording were divided in groups: GC:< 50 VPC/24h (n=11), or GD: > 100 VPC/24h (n=11). The following echocardiographic parameters were analyzed: RV internal dimension during systole and diastole; RV fractional area change (FAC); tricuspid annular plane systolic excursion (TAPSE); myocardial systolic velocity of lateral tricuspid annulus (S’), and global longitudinal strain and strain rate. Groups were compared by Student’ t-test or Mann-Whitney test according distribution, and correlation between conventional and speckle tracking echocardiographic variables, as well as number and severity of the ventricular arrhythmias were accomplished by the Pearson test, assumin... (Complete abstract click electronic access below) / Mestre

No description available.

Ekokardiografi är en mycket användbar teknik som bland annat kan bedöma vänsterkammarensfunktion hos hjärtat med hjälp av ejektionsfraktion (EF) och global longitudinell strain (GLS). EF är idag den metoden som används mest vid bedömning av vänsterkammarfunktionen och beräknas enligt Simpsons biplanmetod. GLS är en ny metod som mäter myokardiets deformation och har i tidigare studier visat sig vara en känslig metod och kan upptäcka förändringar i myokardiet tidigare än EF. Vid behandling av bröstcancer kan hjärtat påverkas toxiskt och därmed genomgår denna patientgrupp regelbundna kontroller med ekokardiografi.   Syftet med denna studie är att jämföra två ekokardiografiska metoder hos 20 stycken kvinnliga bröstcancerpatienter. Jämförelser har gjorts mellan EF beräknat med Simpsons biplanmetod (EFbi) och GLS samt mellan EFbi och EF beräknat från GLS (EFGLS). Detta är en kvantitativ retrospektiv studie där data insamlats mellan oktober-december 2014 på avdelningen klinisk fysiologi vid Länssjukhuset Ryhov i Jönköping. Den analysmetod som använts är McNemar´s test samt kappavärde. Resultatet av studien visar att EFbi och GLS gav en dålig överenstämmelse mellan metoderna och en rimlig överenstämmelse sågs mellan EFbi och EFGLS. Slutsatsen har dragits utifrån kappavärdet. / Echocardiography is a useful technique which can value the function of the left chamber of the heart by using ejection fraction (EF) and global longitudinal strain (GLS). Today EF is the most common method in assessments of the left chamber function and is calculated by Simpson´s biplanemethod. GLS is a new method that measures the myocardial deformation. It has been proved to be a sensitive method and can detect changes in the myocardium earlier than EF.   The purpose of this study is to compare two echocardiographic methods among 20 female breast cancer patients. Comparisons have been made between EF calculated with Simpson´s biplanemethod (EFbi) and GLS, and between EFbi and EF calculated by GLS (EFGLS). This is a quantitative retrospective study. The data used in this study was collected between October – December 2014 at the Department of Clinical Physiology at the Hospital Ryhov in Jönköping. The method used to analyse the results was McNemar´s test and Kappa value. The results of the study showed that EFbi and GLS gave a modest correspondence between the methods. A reasonable correspondence were observed between EFbi and EFGLS. The conclusion has been drawn from the kappa value.