O objetivo do trabalho consiste em avaliar a relação entre o posicionamento dos discos articulares durante a dinâmica dos movimentos mandibulares e o levantamento dos dados clínicos com especial ênfase à dor e sua localização preferencial em um grupo de 74 pacientes sintomáticos sendo 51 do gênero feminino e 23 do gênero masculino, entre 19 a 78 anos de idade, portadores de manifestações compatíveis à processos de degeneração interna das articulações temporomandibulares e as correspondentes imagens por meio de imagens em ressonância magnética em norma sagital. As imagens foram adquiridas com a utilização de aparelho com potência de campo magnético de 1.5 Tesla e bobina de superfície dupla para captação de sinais, segundo protocolo indicado para aquisição multiplanar, com ênfase na série definada como densidade de prótons (DP), que foram posteriormente manipuladas numa estação de imagem independenteworkstation - de alta resolução utilizando-se ferramentas eletrônicas em 4 situações de amplitude de abertura bucal (repouso, 10mm; 20mm; 30mm) para ambos os lados. As análises foram realizadas por dois observadores em tempos distintos e transferidas para tabelas de identificação para elaboração das análises estatísticas. Objetivou-se destacar a importância deste método de imagem como base para o diagnóstico de distúrbios destas articulações, pois em muitas situações as informações clínicas obtidas durante a anamnese não foram ao encontro dos dados imaginológicos. Os dados obtidos foram dispostos em tabelas e gráficos os quais permitiram concluir que não houve vínculo entre os fenômenos de dor e a topografia dos discos e observou-se carência de vínculo dos fenômenos de dor localizada com a correspondente morfologia dos discos. / The objective is to assess the relationship between the positioning of articular discs during the dynamics of the mandibular movements and the lifting of the clinical data with particular emphasis on pain and its location preference in a group of 74 symptomatic patients, 51 females and 23 male, between 19 to 78 years. Pacients presents events aliable with internal degeneration processes of temporomandibular joints and related images through a standard sagittal MRI. The images were acquired with the use of apparatus with power magnetic field of 1.5 Tesla and double surface coil to signals capture, according protocol set out to purchase multiplanar aquirer, with emphasis on the series defined as density of protons (PD), which were then handled at a high resolution self-image workstation - using the electronic tools in 4 cases of oral extent of openness (rest, 10mm, 20mm, 30mm) for both sides. The analyses were performed by two observers at different times and transferred to identification tables focusing statistical analyses. The aim was to highlight the importance of this method of image as a basis for the diagnosis of these joints disorders, because in many cases the information obtained during the clinical history does not meet the imaging data. The data were arranged in tables and graphs which showed that there was no link between the phenomena of pain and topography of the disks and there was lack of linkage of the phenomena of pain located with the corresponding morphology of the disks.

Esta dissertação desenvolve e aplica métodos para caracterizar regiões cerebrais durante o estado de repouso. Utilizam-se grafos para representar a inter-dependência temporal de sinais de ressonância magnética funcional provenientes de regiões cerebrais distintas. Vértices representam regiões cerebrais e arestas representam a conectividade funcional. Buscando superar os problemas de visualização e interpretação desta forma de representação, elaboram-se métodos quantitativos para caracterizar padrões de conectividade entre regiões cerebrais. Para cada sujeito analisado: 1) Faz-se a redução da dimensionalidade espacial das imagens de ressonância magnética funcional respeitando os limites anatômicos das regiões cerebrais. 2) Estima-se a rede de conectividade funcional pela coerência direcionada entre pares de regiões distintas. 3) Constrói-se um grafo direcionado e pesado pela medida de conectividade. 4) Quantificam-se os vértices por índices e faz-se o registro destes valores no espaço comum MNI. 5) Avalia-se a consistência de cada índice pelo teste não paramétrico de Friedman seguido de análises de múltiplas comparações. A análise de 198 imagens de sujeitos sadios produziu resultados consistentes e biologicamente plausíveis. Em sua maioria, revelou regiões associadas a conceitos anatômicos de conectividade e integração cerebral. Embora de implementação simples, o método proporciona informações de natureza dinâmica sobre as relações entre diferentes regiões cerebrais e pode ser utilizado futuramente para estudar e entender desordens psiquiátricas/neurológicas. / This dissertation develops and applies methods to characterize brain regions during resting state. Graphs are used to represent functional MRI connectivity from different brain regions. Vertices represent brain regions and edges represent connectivity. To overcome the visualization and interpretation problems of this form of representation, we developed quantitative methods to characterize its patterns. Methods: For each subject: 1) The reduction of spatial dimensionality of functional magnetic resonance imaging is carried out taking into account the anatomic limits of the brain regions. 2) The network is estimated by directed coherence between pairs of separate regions. 3) A directed graph with weights on its edges is constructed using the later connectivity measure. 4) The vertices are quantified by indexes that are registered in the MNI common space. 5) The consistency of each index is evaluated by the nonparametric Friedman followed by Post-Hoc analysis. Results: The analysis of 198 images of healthy subjects produced consistent and biologically plausible results. They revealed anatomical regions involved in brain integration. Conclusion: The method provides information about the dynamic nature of the relationships between different brain regions and can be used in future clinical studies to understand psychiatric and neurological disorders.

O objetivo do trabalho consiste em avaliar a relação entre o posicionamento dos discos articulares durante a dinâmica dos movimentos mandibulares e o levantamento dos dados clínicos com especial ênfase à dor e sua localização preferencial em um grupo de 74 pacientes sintomáticos sendo 51 do gênero feminino e 23 do gênero masculino, entre 19 a 78 anos de idade, portadores de manifestações compatíveis à processos de degeneração interna das articulações temporomandibulares e as correspondentes imagens por meio de imagens em ressonância magnética em norma sagital. As imagens foram adquiridas com a utilização de aparelho com potência de campo magnético de 1.5 Tesla e bobina de superfície dupla para captação de sinais, segundo protocolo indicado para aquisição multiplanar, com ênfase na série definada como densidade de prótons (DP), que foram posteriormente manipuladas numa estação de imagem independenteworkstation - de alta resolução utilizando-se ferramentas eletrônicas em 4 situações de amplitude de abertura bucal (repouso, 10mm; 20mm; 30mm) para ambos os lados. As análises foram realizadas por dois observadores em tempos distintos e transferidas para tabelas de identificação para elaboração das análises estatísticas. Objetivou-se destacar a importância deste método de imagem como base para o diagnóstico de distúrbios destas articulações, pois em muitas situações as informações clínicas obtidas durante a anamnese não foram ao encontro dos dados imaginológicos. Os dados obtidos foram dispostos em tabelas e gráficos os quais permitiram concluir que não houve vínculo entre os fenômenos de dor e a topografia dos discos e observou-se carência de vínculo dos fenômenos de dor localizada com a correspondente morfologia dos discos. / The objective is to assess the relationship between the positioning of articular discs during the dynamics of the mandibular movements and the lifting of the clinical data with particular emphasis on pain and its location preference in a group of 74 symptomatic patients, 51 females and 23 male, between 19 to 78 years. Pacients presents events aliable with internal degeneration processes of temporomandibular joints and related images through a standard sagittal MRI. The images were acquired with the use of apparatus with power magnetic field of 1.5 Tesla and double surface coil to signals capture, according protocol set out to purchase multiplanar aquirer, with emphasis on the series defined as density of protons (PD), which were then handled at a high resolution self-image workstation - using the electronic tools in 4 cases of oral extent of openness (rest, 10mm, 20mm, 30mm) for both sides. The analyses were performed by two observers at different times and transferred to identification tables focusing statistical analyses. The aim was to highlight the importance of this method of image as a basis for the diagnosis of these joints disorders, because in many cases the information obtained during the clinical history does not meet the imaging data. The data were arranged in tables and graphs which showed that there was no link between the phenomena of pain and topography of the disks and there was lack of linkage of the phenomena of pain located with the corresponding morphology of the disks.

Η εισαγωγή της Μαγνητικής Τομογραφίας (ΜΤ) στην κλινική πρακτική και η συμπληρωματική πληροφορία που δίνει η Φασματοσκοπία Μαγνητικού Συντονισμού (ΦΜΣ) συνιστά μια από τις πιο σημαντικές εξελίξεις στη διάγνωση ασθενών με καρκίνο εγκεφάλου [1]. Παρ’ όλα αυτά, οι εικόνες ΜΤ είναι συχνά δύσκολο να ερμηνευθούν από τους ειδικούς λόγω [2] α/ της υποκειμενικότητας και περιορισμένης εμπειρίας του παρατηρητή στην εκτίμηση εικόνων που παράγει η σχετικά νέα αυτή τεχνολογία, β/ των ποικίλων κλινικών χαρακτηριστικών των όγκων (π.χ. τύπος, διαβάθμιση κακοήθειας κλπ.) και γ/ της ιδιαιτερότητας των όγκων στην αντίθεση που παρουσιάζουν με τον περιβάλλοντα ιστό. Μόνο λιγοστές μελέτες έχουν διεξαχθεί για να χαρακτηρίσουν ιστούς εγκεφάλου μέσω της ανάλυσης ποσοτικών χαρακτηριστικών από εικόνες εγκεφάλου ΜΤ [3, 4]. Ενώ έχει ήδη τονιστεί η αναγκαιότητα συσχετισμού της διαγνωστικής και προγνωστικής πληροφορίας που προέρχεται από εικόνες ΜΤ και σήματα ΦΜΣ στη διεθνή βιβλιογραφία [5], υπάρχουν λιγοστές ανάλογες αναφορές για τον σχεδιασμό και υλοποίηση συστήματος Η/Υ αυτόματης διάγνωσης όγκων εγκεφάλου κάνοντας συνδυασμό ποσοτικής πληροφορίας προερχόμενης από εικόνες ΜΤ και σήματα ΦΜΣ [6, 7]. Οι στόχοι της παρούσας διατριβής εστιάζονται στα παρακάτω: - στη μελέτη, ανάπτυξη και η υλοποίηση υπολογιστικού συστήματος αυτόματης ταξινόμησης όγκων του εγκεφάλου μέσω της ποσοτικής ανάλυσης εικόνων ΜΤ το οποίο θα βελτιώνει την ακρίβεια ταξινόμησης σε σχέση με ήδη υπάρχοντα συστήματα [4, 8, 9], όπως αυτά περιγράφονται στην διεθνή βιβλιογραφία μεταξύ πρωτογενών και δευτερογενών όγκων εγκεφάλου καθώς και μεταξύ γλοιωμάτων και μηνιγγιωμάτων με την χρήση δέντρου ιεραρχικής απόφασης δύο επιπέδων. Επιπλέον, στην ανάδειξη πως η χρήση ενός μη-γραμμικού πολυωνυμικού μετασχηματισμού ελάχιστων τετραγώνων των χαρακτηριστικών υφής έχει ως αποτέλεσμα την βελτίωση της ακρίβειας ταξινόμησης του ταξινομητή πιθανοκρατικού νευρωνικού δικτύου. - στην επέκταση και την βελτίωση του συστήματος αυτόματης ταξινόμησης όγκων του εγκεφάλου χρησιμοποιώντας α/ ογκομετρικές ποσοτικές παραμέτρους εικόνων ΜΤ, β/ ταξινομητή μηχανών διανυσμάτων στήριξης μαζί με τη μεθοδολογία συνάθροισης αποτελεσμάτων ταξινόμησης από τυχαιοποιημένα δείγματα κατηγοριών δημιουργημένων με επαναδειγματοληψία για κάθε κόμβο δέντρου ιεραρχικής απόφασης δύο επιπέδων όπου στο πρώτο επίπεδο πραγματοποιήθηκε διαχωρισμός μεταξύ πρωτογενών και δευτερογενών όγκων εγκεφάλου και στο δεύτερο και μεταξύ γλοιωμάτων και μηνιγγιωμάτων και γ/ έναν τροποποιημένο πυρήνα ακτινικής συνάρτησης βάσης για τον ταξινομητή μηχανών διανυσμάτων στήριξης ο οποίος περιλαμβάνει την τεχνική μη-γραμμικού πολυωνυμικού μετασχηματισμού ελάχιστων τετραγώνων με στόχο την βελτίωση της ακρίβειας ταξινόμησης. - στην περαιτέρω επέκταση και την βελτίωση του συστήματος αυτόματης ταξινόμησης με την εισαγωγή χαρακτηριστικών προερχόμενων από σήματα ΦΜΣ ώστε να διερευνηθεί εάν η χρήση του μπορεί να βελτιώσει τα αποτελέσματα ταξινόμησης μεταξύ μηνιγγιωμάτων και μονήρων μεταστάσεων. Τέλος κάνοντας μια περίληψη, η παρούσα διατριβή διαπραγματεύεται τον σχεδιασμό, ανάπτυξη και υλοποίηση μεθόδων και αλγορίθμων για την επεξεργασία και ανάλυση ιατρικών εικόνων, επικεντρώνοντας ειδικότερα στην εφαρμογή των μεθόδων αυτών για την διάγνωση του τύπου των όγκων εγκεφάλου. Τα πιο βασικά συμπεράσματα που απορρέουν από την παρούσα διατριβή είναι τα ακόλουθα: α/ Το σύστημα ταξινόμησης των τύπων των όγκων εγκεφάλου που σχεδιάστηκε και υλοποιήθηκε αυξάνει τα ποσοστά ορθής ταξινόμησης σε σχέση με τα υπάρχοντα. β/ Η κωδικοποίηση των ιδιοτήτων της υφής που προέρχεται από τον σύνολο του όγκου παρέχει επιπρόσθετη πληροφορία στο σύστημα ταξινόμησης αυξάνοντας τα ποσοστά επιτυχούς διαχωρισμού. γ/ Τα χαρακτηριστικά φασματοσκοπίας μαγνητικού συντονισμού αποτελούν επιπρόσθετη αξία στο χαρακτηρισμό του τύπου των όγκων εγκεφάλου μιας και οδήγησαν στην αύξηση του ποσοστού επιτυχούς διαχωρισμού του συστήματος ταξινόμησης. / The process of brain tumor characterization requires a rather intricate assessment of the various Magnetic Resonance (MR) image and spectroscopic features and is typically performed by experienced radiologists. Despite the inherently subjective nature of many of the decisions associated with this process, an expert radiologist is able to perform this task with a significant degree of precision and accuracy. However, in the effort to deliver more effective treatment, clinicians are continuously seeking for greater accuracy in the pathological characterization of brain tissues. The aim of the present thesis was to design, implement, and evaluate a software classification system for discriminating between different brain tumor types on Magnetic Resonance Imaging (MRI), employing textural and spectroscopic features. The clinical material consisted of sixty seven T1-weighted post-contrast MR brain images (21 metastases, 19 meningiomas, and 27 gliomas), obtained from patients with verified and untreated intracranial tumors. Thirty-six 2-dimensional textural features (2D), from the image histogram and the co-occurrence and run-length matrices, were extracted from each one of 67 MR-images. Similarly, an equal number of 3-dimensional textural features (3D) were also calculated in the attempt to maximize classification performances. Finally, MR-spectroscopy features were also incorporated for improving classification accuracies. Classification methods employed included i/ a modified Probabilistic Neural Network (PNN) and Support Vector Machines (SVM) algorithms, incorporating a non-linear Least Squares Features Transformation (LSFT) into the classifiers and ii/ an ensemble classification scheme employing the LSFT-SVM classifier. The LSFT improved classifiers’ performances, increased class separability, and resulted in dimensionality reduction. For evaluating the performance of the designed classification schemes, evaluations were performed by means of the external cross validation process, which is considered indicative of the generalization performance of the designed classification system to ‘unseen’ cases. It was found that the LSFT features transformation enhanced the performance of the PNN and SVM algorithms, achieving classification accuracies of 73.48 % in distinguishing metastatic from primary tumors and 88.67% in discriminating gliomas from meningiomas. When volumetric 3-dimensional features were employed, these results improved to 88.18% for discriminating between metastatic and primary tumors and 97.33% for distinguishing gliomas from meningiomas. The textural features employed in the design of the optimum classification scheme were associated primarily with image texture homogeneity. Finally, when MR-spectroscopy features were also incorporated, classification accuracy was boosted up from 95% in discriminating meningiomas from metastasis to 100%. The MR-image features that participated in the optimum feature vector were related to the degree of homogeneity, the amount of randomness and the dispersion of the gray-tone intensity values within the texture of the tumor. These textural characteristics are related to textural parameters that physicians employ in diagnosis and they were proportional to the textural imprint of brain tumors, i.e. gliomas have heterogeneous texture while meningiomas appear to be homogeneous in MR imaging. The MR-spectroscopy feature that participated in the optimum feature vector was the Choline (Cho) / N-Acetyl Aspartate (NAA) metabolite integral ratio. It was found that both meningiomas and metastases are characterized from low concentrations of NAA while meningiomas exhibit higher concentrations of Cho than metastases, which could be attributed to increased synthesis of tumor cell membranes. Finally, the proposed system might be of value as an assisting tool for brain tumor characterization on volumetric MRI series.

Made available in DSpace on 2014-06-11T19:35:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-22Bitstream added on 2014-06-13T19:24:31Z : No. of bitstreams: 1 guimaraes_smr_dr_sjc.pdf: 3201830 bytes, checksum: 58a70043a3afb382582bd6952818e7c8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo neste estudo foi investigar a reproducibilidade dos resultados (confiabilidade) e a validade dos testes utilizando exames de imagem por ressonância magnética no diagnóstico da posição do disco articular e no diagnóstico das alterações ósseas do côndilo mandibular da articulação temporomandibular. Para tanto, foram avaliados 90 exames de IRM (180 ATM) realizados num equipamento de ressonância magnética de 1,0 Tesla, em próton-densidade (PD), planos coronal e sagital, usando bobina de superfície. Todas as imagens foram analisadas, individualmente, por um médico e por três cirurgiões-dentistas, especialistas em radiologia, sem conhecimento dos diagnósticos dos demais examinadores e das informações clínicas dos indivíduos (duplo-cego). Os examinadores receberam um guia para orientação e treinamento com imagens impressas a respeito dos quatro diagnósticos pré-definidos para a posição do disco (posição normal, descolamento anterior do disco com redução, deslocamento anterior do disco sem redução ou deslocamento posterior do disco articular) e quatro critérios para as alterações do côndilo mandibular (osso normal, presença de osteófito, erosão condilar ou defeito/aplainamento). A partir da metodologia aplicada, os resultados para confiabilidade interexaminadores foram: concordância variando de moderada à alta para a posição do disco e, de fraca à moderada, para as alterações ósseas do côndilo mandibular. A confiabilidade intraexaminador oscilou de alta à excelente para a posição do disco e, de fraca à moderada, para as alterações ósseas do côndilo mandibular. Para a validade da IRM, comparando os cirurgiões-dentistas com o padrãoouro (médico), obteve-se para a posição do disco articular valores acima de 75,0% para sensibilidade, acima 73,1% para especificidade, acima de 70,4% para VPP, acima de 83,0% para VPN e acima... / The aim of this study was to investigate the reproducibility of results (reliability) and validity of magnetic resonance image examinations (MRI) on diagnosis of disk position and osseous alterations of the mandibular condyle of temporomandibular joint (TMJ). Ninety (90) MRI examinations (180 TMJ) were taken on 1,0 Tesla equipment, on proton-density (DP), coronal and sagittal planes, using surface coil. All images were analyzed by a physician e by three surgeon dentists, specialists in radiology, independently, without the knowledge of others examiners diagnosis or subjects clinical information (double-blind). The examiners received a guide for orientation, training and diagnosing according to the four previous defined possibilities for the disk (normal position, anterior disc displacement with reduction, anterior disc displacement without reduction or posterior disc displacement) and four possibilities for the alterations of mandibular condyle (normal, presence of osteophyte, erosion condyle or deformed/flattening). Based on this methodology, the results of interexaminers reliability were: concordance varying from moderate to high for disc position and, from fair to moderate for osseous alterations of mandibular condyle. For validity of MRI, comparing surgeon dentists to gold-standard (physician), for articular disc posicion values obtained were over 75,0% sensibility, over 73,1% specificity, over 70,4% VPP, over 83,0% VPN and over 78,9% accuracy. For morphology of mandibular condyle values obtained were over 85,0% sensibility, over 83,1% specificity, over 41,3% VPP, over 98,0% VPN and over 84,4% accuracy. It was possible to conclude that examiners (physician and surgeon dentists) were able to evaluate, with reliability and accuracy, the position disk and osseous alterations of mandibular condyle by MRI examination

Esta dissertação desenvolve e aplica métodos para caracterizar regiões cerebrais durante o estado de repouso. Utilizam-se grafos para representar a inter-dependência temporal de sinais de ressonância magnética funcional provenientes de regiões cerebrais distintas. Vértices representam regiões cerebrais e arestas representam a conectividade funcional. Buscando superar os problemas de visualização e interpretação desta forma de representação, elaboram-se métodos quantitativos para caracterizar padrões de conectividade entre regiões cerebrais. Para cada sujeito analisado: 1) Faz-se a redução da dimensionalidade espacial das imagens de ressonância magnética funcional respeitando os limites anatômicos das regiões cerebrais. 2) Estima-se a rede de conectividade funcional pela coerência direcionada entre pares de regiões distintas. 3) Constrói-se um grafo direcionado e pesado pela medida de conectividade. 4) Quantificam-se os vértices por índices e faz-se o registro destes valores no espaço comum MNI. 5) Avalia-se a consistência de cada índice pelo teste não paramétrico de Friedman seguido de análises de múltiplas comparações. A análise de 198 imagens de sujeitos sadios produziu resultados consistentes e biologicamente plausíveis. Em sua maioria, revelou regiões associadas a conceitos anatômicos de conectividade e integração cerebral. Embora de implementação simples, o método proporciona informações de natureza dinâmica sobre as relações entre diferentes regiões cerebrais e pode ser utilizado futuramente para estudar e entender desordens psiquiátricas/neurológicas. / This dissertation develops and applies methods to characterize brain regions during resting state. Graphs are used to represent functional MRI connectivity from different brain regions. Vertices represent brain regions and edges represent connectivity. To overcome the visualization and interpretation problems of this form of representation, we developed quantitative methods to characterize its patterns. Methods: For each subject: 1) The reduction of spatial dimensionality of functional magnetic resonance imaging is carried out taking into account the anatomic limits of the brain regions. 2) The network is estimated by directed coherence between pairs of separate regions. 3) A directed graph with weights on its edges is constructed using the later connectivity measure. 4) The vertices are quantified by indexes that are registered in the MNI common space. 5) The consistency of each index is evaluated by the nonparametric Friedman followed by Post-Hoc analysis. Results: The analysis of 198 images of healthy subjects produced consistent and biologically plausible results. They revealed anatomical regions involved in brain integration. Conclusion: The method provides information about the dynamic nature of the relationships between different brain regions and can be used in future clinical studies to understand psychiatric and neurological disorders.

The thesis deals with the edge detection in the magnetic resonance images and their segmentation. There are adduced the gradient based methods, methods based on zero-crossing in the Laplacian images and also methods combined both of the methods adduced above. These methods are compared to find the best one for the temporo-mandibular joint detection. Consequently sufficient segmentation method for particular parts of the temporo-mandibular joint (the condyle, the acetabulum and the articular disk) separation is chosen.

O estudo analisa experimentalmente a integração tendinosa no túnel ósseo femoral na reconstrução do ligamento cruzado anterior do joelho esquerdo com o tendão do músculo semitendíneo autólogo, utilizando imagens de ressonância magnética, teste biomecânico e análise histológica em 15 coelhos da raça Nova Zelândia. Após os períodos de quatro, oito e doze semanas do procedimento cirúrgico, os animais foram submetidos ao exame de ressonância magnética para avaliar o túnel femoral dos joelhos. A seguir os animais foram eutanasiados e os joelhos foram submetidos a testes de tração em uma máquina de ensaios mecânicos Kratos para verificar a integração do enxerto nos túneis e a exame histológico do túnel femoral. A análise dos resultados demonstrou integração mecânica do tendão no túnel femoral a partir da 4ª semana em todos os animais estudados e observou-se na histologia e nas imagens da ressonância magnética alterações do enxerto e da área ao redor de forma heterogênea, sugerindo um processo de cicatrização do tendão-osso, porém não se pode afirmar que ocorria a integração até a 12 semanas. / The purpose was to verify the incorporation (healing) of the graft of the semitendinous tendon into the femoral bone tunnel after an anterior cruciate ligament reconstruction, and verify the post operative evolution of the biomechanical histology and magnetic resonance image analysis of the graft into the femoral bone tunnel. Fifteen New Zealand white rabbits were submitted to an intra-articular anterior cruciate ligament reconstruction in the left knee, using semitendinous tendon autograft. The rabbits were submitted to an magnetic resonance image at 4, 8 and 12 weeks after surgery, after which they were euthanized. The left knee of each rabbit was disarticulated and the anterior cruciate ligament reconstruction was tested for the biomechanical properties and histological analysis of the femoral tunnel. Every rabbit knee showed incorporation of the tendon at the femoral tunnel as of the fourth week in all of the knees studied. After the fourth week signs of integration occurred in the histological analysis and heterogeneous alterations in the magnetic resonance image of the graft and the surrounding areas, which suggests a healing process. Despite the biomechanical incorporation of the graft in the femoral bone tunnel after the fourth week it was not possible to affirm that there occurred incorporation of the graft until the completion of 12 weeks in histological and magnetic resonance image analysis.

OBJETIVO: O objetivo deste estudo é descrever as características do sinal nas lesões císticas da neurocisticercose nas imagens ponderadas em difusão e os metabólitos encontrados na espectroscopia de prótons. MATERIAL E MÉTODOS: Estudaram-se 38 pacientes (39 lesões) com neurocisticercose, usando-se difusão e espectroscopia de prótons. Os exames foram realizados em um magneto de 1,5 T (Signa Horizon LX: GE Medical Systems). A difusão foi realizada no plano axial, com múltiplos cortes com seqüência eco planar. A espectroscopia de prótons utilizou a seqüência PRESS (point-resolved spectroscopy) com TR of 1500 ms e TE de 30/135 ms. RESULTADOS: Os cistos apresentaram intensidade de sinal similar a do líquido cefalorraqueano (LCR) na difusão e valores de CDA sobreponíveis, variando de 1,36 a 3,18 x 10-3 mm2/s. Os picos detectáveis na espectroscopia foram lactato (96,3%), succinato (48%), alanina (40%), lipídeos (15%), aminoácidos citosólicos (7,5%) e acetato (3,7%). CONCLUSÃO: As lesões císticas da neurocisticercose apresentaram hipossinal na difusão e os picos encontrados na espectroscopia de prótons, em ordem decrescente de freqüência, foram lactato, succinato, alanina, lipídeos, aminoácidos citosólicos e acetato / PURPOSE: The objective of this study is to describe the signal behavior of cystic neurocysticercotic lesions on diffusion-weighted imaging (DWI) and single voxel proton spectroscopy findings. MATERIALS AND METHODS: We studied 38 patients (39 lesions) with neurocysticercosis, using diffusion-weighted images and proton MR spectroscopy. The examinations were performed on a 1.5 T scanner (Signa Horizon LX: GE Medical Systems). DWI was performed in the axial plane, using a multisection single shot echo planar pulse sequence. The single voxel proton spectroscopy technique used was the point-resolved spectroscopy (PRESS) sequence with a TR of 1500 ms, short and long TE of 30/135 ms. RESULTS: The cysts presented similar signal intensity to the CSF on DWI, with comparable ADC values, ranging from 1.36 to 3.18 x 10-3 mm2/s. The detectable peaks were lactate (96.3%), succinate (48%), alanine (40%), lipids (15%), cytosolic amino acids (7.5%) and acetate (3.7%). CONCLUSION: The cysts of neurocysticercosis presented hyposignal on DWI and peaks of lactate, succinate, alanine, lipids, cytosolic amino acids and acetate in proton spectroscopy, in decreasing order of frequency

As imagens por ressonância magnéticas não indispensáveis no diagnóstico e tratamento de tumores do encéfalo devido ao seu alto grau de detalhamento anatômico. A tarefa de segmenta¸cão da região tumoral, nestas, permite uma análise quantitativa mais precisa, viabilizando um melhor acompanhamento da evolução/regressão da doença. Porém, a realização manual de tal trabalho é cansativa e apresenta diversas desvantagens que a tornam proibitiva, fazendo com que nao haja muitos médicos dispostos a realizá-la rotineiramente. Neste trabalho é proposto um sistema para segmenta¸cão automática de tumores do encéfalo. O sistema emprega parâmetros de textura de naturezas diversas, como estatísticos, baseados em modelo, e baseados em transformada, os quais são extraídos de diferentes tipos de imagem comuns à pratica médica (T1, T1 com contraste e FLAIR). As técnicas de análise de textura são capazes de detectar alterações mínimas nos tecidos, às vezes imperceptíveis à visão humana, fato que motiva sua adoção; e podem ser complementadas por informações adicionais como valores de intensidade. O sistema proposto conta com quatro etapas básicas: pré-processamento, extração de características, segmentação e pós-processamento; e baseia-se no uso de uma máquina de vetor de suporte para classificação dos pixeis. Os resultados obtidos mostram que o sistema apresenta uma taxa média de acerto elevada, comparável aos resultados encontrados em trabalhos relacionados, sendo capaz de localizar e delimitar a região tumoral sem necessidade de interação com o usuário. A quantificação dos resultados foi realizada utilizando-se métricas de artigos encontrados na literatura. / Magnetic resonance images are essential in the diagnosing and treatment of brain tumors due to its high amount of anatomic details. The task of segmenting brain tumor regions in these images makes more exact quantitative analysis feasible, allowing a better tracking of the evolution/regression of the disease. Nevertheless, the execution of such task is burdensome, featuring several drawbacks that turns it into a prohibitive one, and makes many doctors unwilling to put it into practice. In this work an automatic brain tumor segmentation system is proposed, in which several types of texture parameters such as statistical, model based and transform based, are applied. Those parameters are extracted from different, extensively used, types of magnetic resonance images (T1, T1 with contrast and FLAIR). Texture analysis techniques are capable of detecting tiny changes in underlying tissue, which are sometimes imperceptible to the human vision, fact that motivates its adoption here. Texture features can also be completed by other kinds of characteristics, such as pixel intensity. The proposed system comprises four basic steps: pre-processing, feature extraction, segmentation, and post-processing, and is based on a support vector machine for pixel classification. Final results shows that the system archived high success rates, which are comparable to results found in related works, and that it was able to locate and delimit tumor areas without any user interaction. For the quantification of the results, some metrics found in papers presented in the literature were adopted.