Sandra M. Rua Ventura

Application of MRI and biomedical engineering in speech production study.

Speech production has always been a subject of interest both at the morphological and acoustic levels. This knowledge is useful for a better understanding of all the involved mechanisms and for the construction of articulatory models. Magnetic resonance imaging (MRI) is a powerful technique that allows the study of the whole vocal tract, with good soft tissue contrast and resolution, and permits the calculation of area functions towards a better understanding of this mechanism. Thus, our aim is to demonstrate the value and application of MRI in speech production study and its relationship with engineering, namely with biomedical engineering. After vocal tract contours extraction, data were processed for 3D reconstruction culminating in model construction of some of the sounds of European Portuguese. MRI provides useful morphological data about the position and shape of the different speech articulators, and the biomedical engineering computational tools for its analysis.

Toward Dynamic Magnetic Resonance Imaging of the Vocal Tract During Speech Production

OBJECTIVES/HYPOTHESIS The most recent and significant magnetic resonance imaging (MRI) improvements allow for the visualization of the vocal tract during speech production, which has been revealed to be a powerful tool in dynamic speech research. However, a synchronization technique with enhanced temporal resolution is still required. STUDY DESIGN AND METHODS The study design was transversal in nature. Throughout this work, a technique for the dynamic study of the vocal tract with MRI by using the hearts signal to synchronize and trigger the imaging-acquisition process is presented and described. The technique in question is then used in the measurement of four speech articulatory parameters to assess three different syllables (articulatory gestures) of European Portuguese Language. RESULTS The acquired MR images are automatically reconstructed so as to result in a variable sequence of images (slices) of different vocal tract shapes in articulatory positions associated with Portuguese speech sounds. CONCLUSIONS The knowledge obtained as a result of the proposed technique represents a direct contribution to the improvement of speech synthesis algorithms, thereby allowing for novel perceptions in coarticulation studies, in addition to providing further efficient clinical guidelines in the pursuit of more proficient speech rehabilitation processes.

Morphologic Differences in the Vocal Tract Resonance Cavities of Voice Professionals: An MRI-Based Study

UNLABELLED The processes that take place during singing and acting are complex. However, morphologic and dynamic studies of the vocal tracts during speech have been gaining greater attention, mainly because of the rapid technical advances being made with magnetic resonance imaging (MRI) and image analysis and processing techniques. OBJECTIVES/HYPOTHESIS AND METHODS: Our aim was to describe the morphologic differences in the vocal tract resonance cavities among voice professionals using MRI, and with the three-dimensional models built from the MRI data, compare the volumes calculated for the whole vocal tract and its major resonance cavities. STUDY DESIGN Prospective study. RESULTS The images acquired during the spoken and singing tasks provided morphologic information about the whole vocal tract cavity and also its two major resonance cavities: the oral and the pharynx cavities; differences were observed in the volumes measured during the production of some vowels. CONCLUSIONS The morphologic differences found in the singing voices indicated an increase in the oral cavity volume, resulting in an increase in the overall volumes measured. In the acting voices, both the resonance cavities of the vocal tract contributed to the differences measured.

Development and assessment of an e-learning course on breast imaging for radiographers: a stratified randomized controlled trial.

Background Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Objective Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. Methods A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. Results A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), P<.001. Stratified analysis showed effect in radiographers (23 pp vs 4 pp; P=.004) but was unclear in students (18 pp vs 5 pp; P=.098). Nonetheless, differences in students’ posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; P<.001), both in students (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; P<.001). Overall, 85% were satisfied with the course, and 88% considered it successful. Conclusions This e-learning course is effective, especially for radiographers, which highlights the need for continuing education.

Imaging of the Vocal Tract based on Magnetic Resonance Techniques

Magnetic resonance (MR) imaging has been used to analyze and evaluate the vocal tract shape through different techniques and with promising results in several application fields. Our main purpose is to demonstrate the relevance of MR and techniques of image processing in the analysis of vocal tract. The extraction of contours of the air cavities from 2D images (slices) allowed the built of several 3D reconstruction image stacks by the combination of orthogonally oriented sets of slices for each articulatory gesture, as a new approach to solve the expected spatial under sampling of the imaging process. In result, these computational models provide valuable information for the enhanced visualization of morphologic and anatomical aspects and are useful for partial measurements of the vocal tract shape in different situations. Potential use of this information can be found in Medical and therapeutic applications as well as in acoustic articulatory speech modeling.

Segmentation of tongue shapes during vowel production in magnetic resonance images based on statistical modelling

Quantification of the anatomic and functional aspects of the tongue is pertinent to analyse the mechanisms involved in speech production. Speech requires dynamic and complex articulation of the vocal tract organs, and the tongue is one of the main articulators during speech production. Magnetic resonance imaging has been widely used in speech-related studies. Moreover, the segmentation of such images of speech organs is required to extract reliable statistical data. However, standard solutions to analyse a large set of articulatory images have not yet been established. Therefore, this article presents an approach to segment the tongue in two-dimensional magnetic resonance images and statistically model the segmented tongue shapes. The proposed approach assesses the articulator morphology based on an active shape model, which captures the shape variability of the tongue during speech production. To validate this new approach, a dataset of mid-sagittal magnetic resonance images acquired from four subjects was used, and key aspects of the shape of the tongue during the vocal production of relevant European Portuguese vowels were evaluated.

Qualidade de imagem em mamografia: apresentação do músculo grande peitoral na incidência oblíqua médio-lateral

Since 2004, formaldehyde (FA) has been classified by the International Agency for Cancer Research as a carcinogen. The FA ranks 25th in the overall United States chemical production, with more than 5 million tons produced each year. Due to its economic importance and varied use, many individuals are exposed to FA at their occupational settings. This study aimed to assess the exposure to FA in two occupational settings – FA production factory and pathology anatomy (PA) laboratories – and relate it to possible health effects by comparing frequency of micronuclei (MN) in peripheral bloodIntroducao: As desigualdades em saude sao reconhecidamente um problema de saude publica. A relacao entre determinantes sociais e as desigualdades em saude sao um achado robusto. Enquanto nos adultos e claro que estas desigualdades socioeconomicas se manifestam no seu estado de saude, a situacao e menos clara nas criancas e adolescentes. Foi entao efetuada uma revisao da literatura sobre a influencia dos determinantes sociais na saude na idade pediatrica. De forma a contribuir para um melhor conhecimento sobre a materia. Metodologia: A pesquisa foi efetuada segundo as normas PRISMA, com base nos termos MeSH: Social Class, Pediatric, Hospital, Emergency Treatment, Socioeconomic factor e Healthcare Disparities, na PubMed, Scielo e nas bases de dados da Cochrane. Foram excluidos artigos de revisao, opiniao bem como artigos que tratavam de questoes de acesso aos cuidados. Foi efetuada uma descricao quantitativa e qualitativa dos resultados. Resultados: Foram selecionadas 17 publicacoes, exceto uma do tipo descritiva, todas referentes a estudos observacionais analiticos, a maioria usando dados retrospetivos. Encontrou-se forte evidencia na relacao entre desigualdades em saude e os fatores socio economicos na idade pediatrica. Conclusao: Apesar de nenhuma das publicacoes selecionadas apresentar dados colhidos em Portugal, e seguro afirmar que e possivel encontrar a mesma relacao na idade pediatrica. E importante estudar mais esta area, identificar os determinantes sociais mais importantes bem como as populacoes mais vulneraveis, para melhor poder planear os cuidados de saude e combater as desigualdades. Palavras-Chave: Desigualdades em Saude, Determinantes Sociais da Saude, Fatores Socio-economicos, Pediatria

3D vocal tract reconstruction using magnetic resonance imaging data to study fricative consonant production

The development of Magnetic Resonance Imaging (MRI) has grown rapidly in clinical practice. Currently, the use of MRI in speech research provides useful and accurate qualitative and quantitative data of speech articulation. The aim of this work was to describe an effective method to extract vocal tract and compute their volumes during speech production from MRI images. Using a 3.0 Tesla MRI system, 2D and 3D images of the vocal tract were collected and used to analyze the vocal tract during the production of fricative consonants. These images were also used to build the associated 3D models and compute their volumes. This approach showed that, in general, the volumes measured for the voiceless consonants are smaller than the counterpart voiced consonants.