Les épilepsies sont des hyperactivités neuronales pathologiques largement distribuées au sein du système nerveux. Aborder la question de l'organisation spatiotemporelle de ces crises est un premier pas crucial vers la dissection des mécanismes qui les sous-tendent. Alors qu'il existe de nombreux modèles d'hyperactivité épileptiforme, il est plus difficile d'étudier les crises spontanées, qui sont altérées par la sédation. Dans cette thèse, j'ai développé une approche combinant l'électroencéphalogramme (EEG) avec l'imagerie fonctionnelle ultrasonore (fUS), sur le rat mobile. Ainsi, sur un modèle d'épilepsie absence, j'ai pu enregistrer simultanément la survenue des crises et les variations hémodynamiques, marqueurs du métabolisme cellulaire. Le suivi additionnel de l'activité hémodynamique n'avait pas d'effet en soi sur l'occurrence et la durée des crises épileptiques. L'analyse des enregistrements a permis de mettre en évidence des corrélations entre les activités électriques et vasculaires durant les crises. Tandis que le thalamus présentait des zones d'hyperperfusion pendant les crises, le cortex présentait des corrélats variables suivant les aires, avec une hyperémie des aires somato-sensorielles accompagnée parfois d'une baisse de perfusion des tissus adjacents. La sensibilité du fUS a révélé, à partir d'événements uniques, qu'une série de pointe-ondes observée par une électrode EEG ne s'accompagne pas toujours d'une hyperactivité vasculaire au même endroit. Ainsi, cette approche permet de délimiter le contour des aires présentant une activité vasculaire pendant les crises et montre une dichotomie partielle entre les composantes électriques et vasculaires des crises. / Epilepsies consist in neuronal hyperactivities distributed across the nervous system that need first to be located in order to later decipher the mechanisms of these pathologies. While there are many models of epileptiform hyperactivity, it is more difficult to study spontaneous seizures, which are altered by sedation. In this thesis, I developed an approach that combines electroencephalography (EEG) and functional ultrasound imaging (fUS), on the mobile rat. Thus, on a model of absence epilepsy, I could record simultaneously the occurrence of seizures and the hemodynamic variations, which reflect cellular metabolism. Seizures were unaltered by the recording protocol, compared to rats with EEG alone. Correlations were observed between electric and vascular activities. The thalamus showed areas of hyperperfusion during seizures. The cortex exhibited different correlates in distinct areas, with hyperaemia in somato-sensory areas, occasionally associated with a decrease in perfusion in adjacent tissue. The sensitivity of fUS, which could resolve blood changes from single occurrences, revealed that series of spike-wave discharges recorded from an EEG electrode were not always associated with vascular hyperactivity in the same region. Thus, this approach can delimit the contour of areas presenting vascular activity during seizures and shows a partial dichotomy between the electric and vascular components of seizures.

Made available in DSpace on 2017-07-10T17:48:29Z (GMT). No. of bitstreams: 1 Bianchecci_Danielli_Conte.PDF: 1308564 bytes, checksum: 046371656b2367e67b20775d20072c2b (MD5) Previous issue date: 2011-12-09 / Fundação Araucária / This study aimed to predict the fillet weight (PF) and fillet yield (RF) of Nile tilapia (Oreochromis niloticus) from external measures, measured by morphometry and measures of epiaxial muscles using ultrasound and validate the estimated equations using another sample biometric data. A total of 102 adult fish GIFT lineage, reversed males weighing between 260 and 580 g had the total weight (PT) and body circumference average (CR) all measured by ultrasonography in four predefined body regions (1) between the basis of anterior (2) between the basis of anteriour insertion of anal fin to the last hard ray of dorsal fin. (3) between the final insertion of anal and dorsal fins and (4) between the ventral and dorsal insertion of caudal fin. The prediction equations from the measurements performed on 50 samples were analyzed by statistical procedures backward and stepwise. The measurements made in remaining 52 samples were used for validation of predictive equations to PF and RF. The validation were made from adjustment of linear models first degree of values observed above the values predict on each regression equation set. The equations PFx and RFx estimated from data collected of ultrasound images showed coefficient of determination (R2) of 0.53 (PF1 = -17.35 + 3.66HD2 45.20LE4 + 0.55AE2 + 4.64AE4) e 0.15 (RF1 = 26.66 + 0.043AE2), in backward, and 0.53 (PF2 = -58.03 + 5.65HE4 + 0.33AD1 + 0.65AD2) e 0.19 (RF2 = 25.02 + 0.051AD2), in stepwise. The inclusion of measures of CR and PT as regressive equations did allow the equations to show higher values of R2 such as 0.97 (PF3= - 52.25 1.26HE1 2.03HE3 + 0.40PT +0.51CR e PF4 = -18.12 1.20HE1 + 0.425PT) and 0.73 (RF3 = 17.83 0.29HE1 0.49HE3 + 0.02PT + 0.13CR), in backward and stepwise, and 0.68 (RF4 = 26,14 - 0,27HE1 + 0,027PT), in stepwise, and lower values of mean square of residue that these regression models presented high adherence to data of PF and RF. About the validation of prediction equations all of it were effective in estimating the PF and RF in the sample evaluated. The equations (P = 1.0000) PF3, PF4 (P = 0.5401), RF3 (P = 1.0000) and RF4 (P = 0.8363) were the most accurate and applicable in predicting PF and RF in Nile tilapia. The height of the left side body regions 1 and 3, measured by ultrasound images, together with the average body weight and circumference, are important in predicting of regressive of PF and RF of Nile tilapia. The regression equations, PF3, PF4, RF3, and RF4 are recommended for estimating the PF and RF of Tilapia in phenotypic males adult Nile tilapia GIFT lineage, weighing between 260 and 580 g / Este estudo teve por objetivos predizer o peso de filé (PF) e o rendimento de filé (RF) de tilápia do Nilo (Oreochromis niloticus), a partir de medidas externas mensuradas por morfometria e medidas da musculatura epiaxial, mensuradas por ultrassonografia, e validar as equações estimadas utilizando outra amostra de dados biométricos. Um total de 102 peixes adultos, da linhagem GIFT, machos invertidos, pesando entre 260 e 580 g, foram avaliados quanto ao peso total (PT), circunferência corporal média (CR) e mensurados por ultrassonografia em quatro regiões corpóreas pré-definidas: (1) entre a base de inserção anterior da nadadeira pélvica até o término anterior da nadadeira dorsal, (2) entre a base da inserção anterior da nadadeira anal até o último raio duro da nadadeira dorsal, (3) entre a inserção final das nadadeiras anal e dorsal e (4) entre a inserção ventral e dorsal da nadadeira caudal. As equações de predição a partir das mensurações realizadas em 50 exemplares foram analisadas pelos procedimentos estatísticos backward e stepwise. As mensurações feitas nos 52 exemplares restantes foram utilizadas para a validação das equações preditoras para PF e RF. A validação foi feita a partir do ajuste de modelos lineares de 1° grau dos valores observados sobre os valores preditos por cada equação de regressão definida. As equações PFx e RFx, estimadas em função dos dados coletados das imagens ultrassonográficas, apresentaram valores de coeficiente de determinação (R²) de 0,53 (PF1 = -17,35 + 3,66HD2 - 45,20LE4 + 0,55AE2 + 4,64AE4) e 0,15 (RF1 = 26,66 + 0,043AE2), no backward, e 0,53 (PF2 = -58,03 + 5,65HE4 + 0,33AD1 + 0,65AD2) e 0,19 (RF2 = 25,02 + 0,051AD2), no stepwise. A inclusão das medidas de CR e PT como regressoras permitiu que as equações apresentassem R² mais elevados, com valores de 0,97 (PF3 = - 52,25 - 1,26HE1 - 2,03HE3 + 0,40PT +0,51CR e PF4 = -18,12 - 1,20HE1 + 0,425PT) e 0,73 (RF3 = 17,83 - 0,29HE1 - 0,49HE3 + 0,02PT + 0,13CR), no backward e no stepwise, e 0,68 (RF4 = 26,14 - 0,27HE1 + 0,027PT), no stepwise, e menores valores de quadrado médio do resíduo, indicando que esses modelos de regressão apresentaram elevada aderência aos dados de PF e RF. Na validação das equações preditoras, todas foram eficientes em estimar o PF e o RF na amostra avaliada. As equações PF3 (P = 1,0000), PF4 (P = 0,5401), RF3 (P = 1,0000) e RF4 (P = 0,8363) foram as mais precisas e aplicáveis na predição de PF e RF em tilápia do Nilo. A altura do lado esquerdo nas regiões corporais 1 e 3, mensuradas por imagens ultrassonográficas, em conjunto com o peso e a circunferência corporal média, são regressoras importantes na predição do PF e RF de tilápia do Nilo. As equações de regressão PF3, PF4, RF3 e RF4 são recomendadas para estimar o PF e o RF de tilápia no Nilo adultas, machos fenotípicos, linhagem GIFT, com peso entre 260 e 580g

Lors d'un accident de voiture, l'abdomen peut être soumis à des chargements rapides pouvant entrainer des blessures des organes abdominaux. Bien que les modèles éléments-finis humains soient de plus en plus utilisés pour la prédiction de ces blessures pendant un choc, la validation de leur comportement interne reste difficile en particulier à cause d'un manque de données expérimentales disponibles. En effet, la vitesse de tels chargements ne permet pas d'utiliser des moyens d'imagerie « classiques » tel que l'IRM. Basé sur une récente technique d'imagerie (échographie ultra-rapide), ce travail porte sur l'étude du comportement interne de l'abdomen pendant un chargement rapide. D'une part, des essais de chargement rapides ont été menés sur sujet cadavérique permettant de mettre en évidence des relations entre le chargement externe et la cinématique interne du foie. Ces essais ont été simulés en utilisant un modèle humain existant et des tendances similaires ont pu être observées pour certains des résultats expérimentaux. D'autre part, afin d'aider à l'exploitation des données échographiques dans ce contexte, une méthode numérique a été développée permettant de calculer des cartes de déformations d'organe à partir d'images échographique ultra-rapide. Cette méthode a d'abord été évaluée numériquement et expérimentalement. Puis elle été appliquée à des images échographiques de reins isolés soumis à des chargements rapides (humain et porc) issus d'une précédente étude permettant de mettre en évidence l'influence de paramètres tels que la vitesse sur les déformations 2D des différentes régions de l'organe. Dans l'ensemble, ces travaux ont permis de progresser sur la connaissance de la réponse de l'abdomen au choc, et de mettre en évidence les limites de performances des modèles actuels de l'être humain. La méthodologie développée afin de calculer les cartes de déformation devrait aider à renforcer ces connaissances dans le futur / During an automotive accident, the abdomen can be subjected to rapid loading leading to abdominal organ injuries. Although human body models become increasingly prevalent to predict injuries during an impact, the validation of their internal response is difficult, in particular due to the lack of data available. Such impact last less than ten milliseconds making the use of standard imaging (e.g. MRI) tools difficult. Based on a recent imaging modality (ultrafast ultrasound imaging), this work focuses on the study of the internal response of the abdomen during an impact. The in situ internal response of abdominal organs (liver, colon) was observed during impacts delivered to post mortem human surrogates. For the first time, trends were found between the external response and the internal organ kinematics. These tests were simulated using an existing human body model leading to similar trends for some of the responses. Also, a method was developed allowing estimating 2D strains in organs during an impact based on ultrafast ultrasound images. This method was first evaluated numerically and experimentally. Then, it was used to process images of human and porcine kidneys during an impact from a previous study. Results highlight the influence of parameters such as the impact speed on the 2D strains estimated in different organ regions.Overall, this research allowed improving upon the current knowledge on the internal response of the abdomen subjected to impact. It also showed the performance limitation of current human body models. The method developed to compute strain maps should help to further improve that knowledge in the future

Dans le domaine de l'imagerie médicale ultrasonore, la connaissance du déplacement du milieu imagé est une donnée clinique très importante dans de nombreux examens, parmi lesquels nous pouvons citer les examens Doppler ou les examens d'élastographie. Dans la littérature, les deux principales familles de méthodes permettant d'estimer le déplacement sont les méthodes de mise en correspondance de blocs et les méthodes Doppler. Les méthodes de mise en correspondance de blocs estiment le déplacement en comparant des vignettes prises dans les images ultrasonores avant et après déplacement. Elles dépendent donc de la méthode utilisée pour former les images. Les méthodes Doppler mesurent quant à elles le déplacement suivant une direction particulière, ce qui limite leur gamme d'utilisation à l'estimation de champs de déplacements simple. Dans cette thèse, nous avons proposé un formalisme, ainsi que trois méthodes, permettant d'estimer le déplacement 2D directement à partir de ces signaux bruts. Cette approche permet de s'affranchir de la dépendance envers la méthode de formation d'images, tout en permettant l'estimation de champs complexes. Nous avons mis en évidence le concept de vecteur normal, liant le déplacement réel de milieu aux décalages temporels de long des signaux bruts. Le formalisme général est appliqué à plusieurs séquences ultrasonores: la première méthode d'estimation utilise des signaux acquis à l'aide d'éléments uniques de la sonde; la deuxième est basée sur l'utilisation d'ondes planes et la troisième méthode s'appuie sur une séquence utilisant des faisceaux focalisés. Les méthodes d'estimation directe du mouvement ont été validées en simulation et expérimentalement, et leurs performances ont été comparées à une méthode de référence: la mise en correspondance de blocs. Les méthodes proposées améliorent significativement la précision de l'estimation du champ de déplacement par rapport à la méthode standard, en atteignant une précision de 1.5µm dans la direction transverse et une précision de 2.5µm dans la direction axiale pour une fréquence de travail de 5MHz. Nous avons également développé une méthode de formation d'images améliorant la résolution spatiale. Cette méthode utilise les spectres de signaux RF acquis avec des ondes planes pour former le spectre de l'image ultrasonore. Elle fournit les images utilisées par la méthode d'estimation du mouvement de référence. / In the field of medical ultrasound imagery, the knowledge of displacement is an important input for many clinical exams, including color Doppler and elastography. In the literature, the two main way proposed for solving the displacement field estimation are blockmatching techniques and Doppler methods. Blockmatching techniques try to match part of images acquired before and after the displacement and depends on the way those images where created. On the other hand, Doppler methods only estimate displacement along a fixed direction. In this thesis, we proposed three methods that can be used to estimates directly the motion field from raw RF signals by using the proposed concept of normal vector. This concept models how displacement will change RF signals. The proposed methods are compared in simulation and experimentally to a reference blockmatching technique and show a improvement of resolution. Proposed methods resolution are up to 1.5µm in the transverse direction and 2.5µm in the axial direction at a frequency of 5MHz. We also proposed a new beamforming technique that estimate the spectrum of the ultrasound image. This method is compatible with RF signals used by motion estimation methods.

La radiologie est actuellement la modalité d'imagerie la plus utilisée en chirurgie orthopédique, que ce soit en planification opératoire, en contrôle per-opératoire ou pour le suivi du patient. Un de ses inconvénients est de ne pas permettre un référencement géométrique des objets représentés. Il est donc impossible tout au long du processus chirurgical orthopédique, de mesurer précisément les modifications de géométrie des structures osseuses. En salle d'opération les instruments chirurgicaux sont référencés spatialement et permettent par palpations de points de référence une identification géométrique des structures osseuses. Ceci est limité au contexte chirurgical car ces palpations requièrent des incisions. Dans cette thèse, nous proposons d'introduire en chirurgie orthopédique une nouvelle approche fondée sur l'utilisation d'un capteur d'images ultrasonores dont le positionnement spatial est connu. Nous présentons une méthode d'analyse d'images ultrasonores qui aboutit à la détection des points de référence dans un contexte non chirurgical. Cet apport est fondamental car il introduit une continuité dans le contrôle précis de la géométrie des structures osseuses tout au long du processus chirurgical orthopédique de la planification opératoire jusqu'au suivi du patient. Pour déterminer la position des points de référence sur les images ultrasonores osseuses nous sommes passés par une étape intermédiaire consistant en la détection de l'interface osseuse par des approches fondées sur des modèles de contours. Devant la difficulté du problème lié à la très faible qualité des images ultrasonores osseuses, nous nous sommes orientés vers une approche coopérative innovante. Dès que la sonde est positionnée sur le patient, le système affiche en temps réel le contour détecté et le clinicien peut, par un mouvement continu de la sonde, faire converger le système vers une solution optimale au regard de son expertise et des propriétés images. La validation de nos algorithmes s'est tout d'abord effectuée en mode non coopératif sur une base de données contenant 651 images ultrasonores. Le meilleur algorithme fondé sur la recherche d'un chemin optimal parmi un ensemble de points de contours candidats a été validé en mode coopératif sur un prototype appelé PhysioPilot dédié à la mesure de paramètres physiologiques dans un contexte non chirurgical / X-rays remain the preferred imaging modality for orthopedic surgery for surgical planning, intra-operative control or patient follow-up. Nevertheless, it does not allow anatomical bone structures referencing. It is then impossible to control geometrical modifications of bone structures during the surgical process. However, surgical tools are referenced in the operating-room space and allow the surgeon to define anatomical structures geometrically by defining landmark positions. This process is only allowed during surgical procedures because it requires to do cuts on the patient. In this work, we propose a new approach using an ultrasound probe that is referenced in the operating-room space. We present an image processing algorithm to extract anatomical landmark position in a surgical context. It is a crucial improvement because it allows a complete patient follow-up from pre-operative planning to post-operative consults. To determine anatomical landmark positions on ultrasound images we added an intermediate step to extract the bone/soft tissues interface via several segmentation methods as active contours. Due to the low quality of ultrasound images we decided to design a innovative cooperative process. As the surgeon positions the ultrasound probe on the patient, the bone interface appears on the system screen in real time. Then the clinician can help the segmentation result to converge to the final solution by a soft movement of the probe. The validation of our work was performed on a database of 651 ultrasound images, in a non-cooperative way. The best algorithm that extracts the bone interface by defining the optimal path in a graph of potential candidates was validated with a cooperative protocol on a prototype called PhysioPilot, in order to perform physiological measurements in a non-surgical context

Ce travail s'intéresse au suivi spatio-temporel par imagerie ultrasonore de la cavitation acoustique. Celle-ci est un phénomène physique complexe utilisé au cours de certaines techniques de thérapie par ultrasons, correspondant à la formation de bulles de gaz qui oscillent et éclatent. Initialement, la méthode TD-PAM (Time Domain Passive Acoustic Mapping, en anglais), a été développée pour cartographier l’activité de cavitation à partir des signaux acoustiques émis par les bulles, enregistrés passivement par une sonde linéaire d'imagerie ultrasonore. Toutefois, le TD-PAM souffre d’une trop faible résolution et de nombreux artefacts de reconstruction. De plus, il est lourd en temps de calcul car il est formalisé dans le domaine temporel (TD). Pour pallier ces deux limitations, il est proposé d'étudier, de comparer et de développer des méthodes avancées d'imagerie ultrasonore passive. Ce manuscrit s'articule autour de trois contributions principales : Une méthode adaptative originale a été formalisée dans le domaine temporel, reposant sur la compression d'amplitude des signaux ultrasonores par racine pième : le TD-pPAM. Cette approche améliore la résolution et le contraste des cartes de cavitation pour un temps de calcul équivalent au TD-PAM. La notion de matrice de densité inter-spectrale a été introduite pour l'imagerie de la cavitation. Dès lors, quatre méthodes dans le domaine de Fourier (FD) ont été étudiées et comparées : le FD-PAM (non-adaptatif), la méthode Robuste de Capon FD-RCB (adaptatif, par optimisation), le Functional Beamforming FD-FB (adaptatif, par compression non-linéaire) et la méthode MUltiple Signal Classification FD-MUSIC (adaptatif, par projection en sous-espaces). Les performances de ces méthodes FD ont été étudiées expérimentalement in vitro cuve d’eau avec une comparaison par imagerie optique. Les méthodes adaptatives FD proposées ont démontré leur potentiel à améliorer le suivi spatio-temporel des bulles. Le FD-RCB offre une localisation supérieure au FD-PAM mais souffre d'une importante complexité algorithmique. Les performances du FD-FB sont intermédiaires à celles du FD-PAM et du FD-RCB, pour une complexité de calcul équivalente au FD-PAM. Le FD-MUSIC a le potentiel de mettre en évidence de faibles sources acoustiques, mais ne conserve pas leurs quantifications relatives / This work focuses on the spatio-temporal monitoring of acoustic cavitation by ultrasonic imaging. This is a complex physical phenomenon used in some ultrasound therapy techniques, corresponding to the formation of gas bubbles that oscillate and implode. Initially, the TD-PAM (Time Domain Passive Acoustic Mapping) method was developed to map cavitation activity from acoustic signals emitted by bubbles, passively recorded by a linear ultrasonic imaging probe. However, the TD-PAM suffers from too low resolution and many reconstruction artifacts. In addition, it is time-consuming because it is formalized in the time domain (TD). To overcome these two limitations, it is proposed to study, compare and develop advanced methods of passive ultrasound imaging. This manuscript is structured around three main contributions: An original adaptive method has been formalised in the time domain, based on the amplitude compression of ultrasonic signals by root pth: TD-pPAM. This approach improves the resolution and contrast of cavitation maps for a computing time equivalent to the TD-PAM. The notion of cross-spectral density matrix has been introduced for cavitation imaging. Four Fourier domain (FD) methods were therefore studied and compared: FD-PAM (non-adaptive), Capon Robuste FD-RCB (adaptive, by optimization), Functional Beamforming FD-FB (adaptive, by non-linear compression) and MUltiple Signal Classification FD-MUSIC (adaptive, by subspaces projection). The performance of these FD methods was studied experimentally in vitro in water tank with a comparison by optical imaging. The proposed adaptive FD methods have demonstrated their potential to improve the spatial and temporal tracking of bubbles. The FD-RCB offers a superior localization to the FD-PAM but suffers from a high algorithmic complexity. The performance of the FD-FB is intermediate to that of the FD-PAM and the FD-RCB, for a calculation complexity equivalent to the FD-PAM. The FD-MUSIC has the potential to highlight weak acoustic sources, but does not keep their relative quantifications

Background: Low back pain (LBP) is often associated with lumbar spinal instability (LSI). The multifidus muscle is considered a stabilizer of the spine and has been studied extensively with Rehabilitative Ultrasound Imaging (RUSI). There may be a relationshipbetween clinical signs of LSI, decreased cross-sectional area (CSA) of the multifidus and weakness. Having the ability to detect multifidus weakness without the use of RUSI may serve to be invaluable to the clinician in detecting multifidus weakness.Purpose: To investigate the relationship between the modified prone straight leg raise test (MPSLR) and CSA of the multifidusmuscle as measured by RUSI and to investigate the relationship between MPSLR and RUSI findings with the presence of low back pain symptoms that interfere with regular daily activities. Subjects: Participants consisted of two groups of subjects. One group (n=30, 87% male) comprised individuals in general good health, aged 18-55, without history of back pain. The second group (n=36, 56% male) comprised individuals aged 18-55, with history of low back pain within the past 12 months. Methodology: Subjects performed a MPSLR test to identify multifidus weakness. All subjects repeated the same test with concurrent RUSI to visualize the multifidusand measure its CSA. Results: A significant association between a positive MPSLR, asymmetry of the multifidus, and pain was observed (p r = .049, p = .696) was not observed. A sensitivity of 94% and a specificity of 63% was also discovered in the ability of the MPSLR test to detect asymmetry of themultifidus muscle within subjects. A positive MPSLR combined with a high Oswestry score of 25-30 further reinforced the probability of pain (p < .001) Conclusion: The MPSLR test demonstrated a strong association between a positive test and asymmetry of themultifidus muscle within subjects. Clinical Relevance: The MPSLR test can be used to identify patients at risk for LBP symptoms due to asymmetrical changes in the multifidus muscle of the lumbar spine, and aid in directing an appropriate rehabilitation approach to those patients in need of specific multifidus exercise prescription.

Vacuum assisted delivery (VAD) is a common procedure used in the final stage of labor in the situation of a difficult natural delivery. Since the only biomechanical studies concerning the clinical safe traction force were conducted during 70s using simplified models to mimic the fetal head, concerns remain regarding the side effects of this medical intervention when applying high levels of traction forces. For experimental evaluation of VAD, a tissue-mimicking accurate fetal head phantom, having the same skull and brain dimension as a newborn, as well as, proper mechanical and acoustic properties of materials, can be used as a useful resource in terms of establishing safe levels of traction forces. The goal of this project is to develop a realistic patient-specific fetal head phantom that will be used to investigate the relation between applied traction force and imposed brain deformation in VAD in an experimental setting. A realistic fetal head phantom was developed using geometry accurate segmented meshes of pediatric skull and brain from a CT fetal head dataset. The fetal skull was 3D printed while the segmented mesh of the brain was used to create a fetal brain mold. The fetal brain phantom was developed using a PVA and graphite solution (10% and 3% mass concentration), whereas the sutures and fontanels, the scalp and the cerebrospinal fluid were mimicked using silicone, surgical latex and water, respectively. All the tissue-mimicking materials used corresponded with the biomechanical properties of the fetal head tissues. After the construction of the fetal head phantom, grey-scale long- and short- axis ultrasound images as well as the fetal brain phantom elasticity map were obtained. Furthermore, using sonomicrometry crystals, the reference strain values during manual hand pressure and VAD experimental procedures were acquired. The results showed negative strain values (compression) reaching 15% in the manual pressure experimental procedure, and higher positive strain values (stretching) reaching over 40% in the VAD experimental procedure. However, due to experimental limitations only one measurement using clinically realistic levels for both vacuum pressure (65 kPa) and traction force (70 N) was achieved. The developed fetal head phantom has potential to provide trustful biomechanical evidence to guide safe vacuum assisted delivery as well as to provide useful resource in terms of defining the clinical effective force of the vacuum extractor (VE). / I slutskedet av svåra vaginala förlossningar är assistans med sugklocka vanligt förekommande. Eftersom de enda biomekaniska studierna om kliniskt säkra dragkrafter genomfördes under 70 -talet med hjälp av förenklade modeller för att efterlikna fostrets huvud, finns det fortfarande oro om vilka skador användandet av sugklocka kan leda till när höga dragkrafter används. För att kunna fastställa en säker nivå av dragkrafter skulle en modell av fosterhuvudet, med realistiska dimensioner samt liknande mekaniska och akustiska egenskaper som en nyfödd, kunna användas.  Målet med detta projekt är att utveckla en realistisk patientspecifik modell av fosterhuvudet och sedan använda den för att experimentellt undersöka sambandet mellan applicerad dragkraft och hjärndeformation.  En realistisk fosterhuvudsmodell utvecklades från segmenterade datortomografibilder på ett fosterhuvud. Skallbenet tillverkades med en 3D-skrivare medan hjärnans gjöts i PVA och grafit (10% och 3% masskoncentration) i en 3D-utskriven form. Suturerna och fontanellerna, skalpen och cerebrospinalvätskan efterliknades med silikon, kirurgisk latex respektive vatten. Alla vävnadsimiterande material som användes motsvarade de biomekaniska egenskaperna hos ett fosters huvud.  När modellen var färdigkonstruerad togs ultraljudsbilder i gråskala i både lång- och kortaxel. Även hjärnmodellens elasticitet mättes med ultraljudsbaserad skjuvvågselastografi. Sonomikrometri –kristaller användes för att samla in referensvärden på hjärndeformation vid manuellt handtryck och experimentell rekonstruktion av förlossning med sugklocka. Resultaten visade att negativ deformation (kompression) på 15% i experimentella rekonstruktionen av förlossning. På grund av experimentella begränsningar uppnåddes dock endast en mätning med kliniskt realistiska nivåer för både vakuumtryck (65 kPa) och dragkraft (70 N).  Den utvecklade fosterhuvudsmodellen har i vidare studier potential att tillhandahålla tillförlitliga biomekaniska bevis för att vägleda säker vakuumassisterad förlossning samt för att definiera kliniska effektiva krafter i en sugklocka.

<p>This thesis presents a family of automatic elastic registration methods applicable to single and multimodal images of similar or dissimilar dimensions. These registration algorithms employ a generic dynamic linear elastic continuum mechanics model of the tissue deformation which is discretized using the finite element method. The dynamic deformation model provides spatial and temporal correlation between images acquired from different orientations at different times. First, a volumetric registration algorithm is presented which estimates the deformation field by balancing internal deformation forces of the elastic model against external forces derived from an intensity-based similarity measure between images. The registration is achieved by iteratively solving a reduced form of the dynamic deformation equations in response to image-derived nodal forces. A general approach for automatic deformable image registration is also presented in this thesis which deals with different registration problems within a unified framework irrespective of the image modality and dimension. Using the dynamic deformation model, the problem of deformable image registration is approached as a classical state estimation problem with various image similarity measures providing an observation model. With this formulation, single and multiple-modality, 3D-3D and 3D-2D image registration problems can all be treated within the same framework.The registration is achieved through a Kalman-like filtering process which incorporates information from the deformation model and an observation error computed from an intensity-based similarity measure. Correlation ratio, normalized correlation coefficient, mutual information, modality independent neighborhood descriptor and sum of squared differences between images are similarity/distance measures employed for single and multiple modality image registration in this thesis</p> / Doctor of Philosophy (PhD)

Background: Pelvic floor muscle (PFM) training is recommended as first line conservative management for stress urinary incontinence (SUI). The fundamental issue of how to optimally contract the PFM has not previously been investigated. An effective voluntary PFM contraction is known to positively influence the bladder neck and urethra which are urethrovesical (UV) structures associated with continence. The PFM may be globally or selectively contracted according to cue to instruction. The main research question was to investigate which cue to instruction for a PFM contraction has the potential to optimise position of UVSs following a brief period of practice in continent nulliparous pre-menopausal women (aiming to provide normative data) and parous menopausal women with previously unreported SUI. Hypotheses: Posterior or combined cues for instruction of PFM contraction are more influential in optimising UV position (UVP) during PFMC following brief practice than an anterior cue. Posterior or combined cues are equally influential in altering UVP. Aims: Preliminary aim was to investigate the reliability and suitability of 2-DRTUS and angle of urethral inclination (AUI) for imaging of selective contraction of the PFM and ease of reading images by a non diagnostic imaging researcher. Principal aim was to investigate if there is an optimal cue to instruction for a PFM contraction in two groups of women. Study 1: pre menopausal nulliparous continent women (to provide normative data) and Study 2: post menopausal parous stress incontinent women. Secondary aims were investigation of posture; ability to selectively contract the PFM contraction; and cue preference. Method: Study 1: Twenty women who were able to effectively and selectively contract were taught the following cues: anterior; posterior; anterior and posterior combined. Following 4 weeks of practice, perineal 2-D RTUS images of three PFMC for each cue were captured in supine and standing twice (for repeatability analysis) five minutes apart. Two raters measured AUI. Data analysis was undertaken using a Customized General Linear Model (GLM) ANOVA with Bonferroni correction for interactions between all variables; subject, cue, posture and test. Seventeen data sets were available for analysis. Study 2: Methodology was based on Study 1. Twenty-one women were taught the study cues, followed the practice protocol and underwent data collection in the supine position. Twenty-one sets of data were available for analysis. Results: Reliability: ICC [1,3] for intra rater reliability was 0.957 [CI 95%: 0.946 to 0.967 p=0.000], inter rater reliability [2,1] 0.820 [CI 95%: 0.768 to 0.861] and for repeatability [1,3] 0.781 [CI 95%: 0.690 to 0.849 p=0.000] (continent) and 0.954 [CI 95%:0.931 to 0.971 p=0.000] (incontinent). Principal results Study 1: anterior vs posterior cues (difference) 3.979˚ (CI 95%: [0.503 to 7.455 p=0.021]); anterior vs combined 3.777˚ (CI 95%: [-0.099 to 6.853 p= 0.059]) posterior vs combined cues -0.602˚ (CI 95%: [-2.874- 4.078 p=1.00]). Aggregated data from tests 1 and 2: anterior vs posterior 4.240° (CI 95%: [1.213 to 7.267 p=0.003]); anterior vs posterior 3.756° (95%CI: [0.729 to 6.783 p=0.009]); posterior vs combined-6.48° (95% CI: [-3.511 to 2.542 p=1.000]). Principal results Study 2: anterior vs posterior 3.936˚ (95%CI: [0.863 to 7.008p=0.008]; 4.946˚ anterior vs combined (95%CI: [1.873 to 8.018 p=0.001]); posterior vs combined 1.010° (95%CI: -[2.062 to 4.082 p=1.000]). Aggregated analysis was anterior vs posterior 3.703˚ (95%CI: [1.639 to 5.761 p=0.000]); anterior vs combined 5.089˚ (95%CI: [3.0287 to 7.1503 p=0.000]) and posterior and combined 1.389° (95%CI: [-0.672 to 3.450 p=0.309]). Secondary results: 2-D RTUS and the AUI were found to be suitable for investigating selective PFM contraction. Posture: supine vs standing (difference) 9.496˚ (p=0.000); (posture did not affect absolute AUI). Three continent (13%) and 2 incontinent (7%) subjects were unable to selectively contract the PFM. Cue preference in both studies was posterior or combined. Conclusions: AUI was significantly narrower/optimal when instruction for PFM contraction included a posterior cue, in both continent and stress incontinent women. This is proposed to be due to optimal recruitment of puborectalis. Puborectalis may be more important in urinary continence than widely recognized. This study has provided seminal information with respect to optimal cue to contraction for a PFM contraction and will change practice. Investigation of the potential impact of these findings clinically is required. It is proposed that further understanding will lead to standardisation of PFM instruction, ease of comparability between PFM research studies, and will clarify PFM instructions for the media and lay public.