Browsing by Author "Vieira, Lina"
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- Addressing the patient experience in myocardial perfusion scintigraphyPublication . Grilo, Ana Monteiro; Vieira, Lina; Carolino, Elisabete; Ferreira, Jéssica; Neves, MariaBackground: Myocardial Perfusion Scintigraphy is a medical exam whose purpose is to evaluate myocardial perfusion. This examination due to their procedures can generate some anxiety in patients that can disturb the good performance of the exam. The main objective of this study is to perform an analysis of patient's undergoing myocardial perfusion scintigraphy experience, assess patient`s anxiety and check Nuclear Medicine Department communication and information effectiveness. Material and methods: For this study, the State-Trait Anxiety Inventory (STAI) and two Scan Experience Questionnaires were used. Sixty patients answered the questionnaires before and after myocardial perfusion scintigraphy. Results: Patients reported medium levels of scan-related anxiety and trait anxiety before the myocardial perfusion scintigraphy. After the scan, there is a slight decrease in patients' anxiety. Results of the scan, radiation used, duration of the scan and the injection of the radiopharmaceutical are the most relevant patients' concerns before the scan. 15% of the sample did not receive the necessary information or the most effective way. Conclusions: The results suggest that there are several factors that tend to trigger the patient's experience and anxiety. Strategies to improve patient myocardial perfusion scintigraphy experience at Nuclear Medicine Department are presented.
- Adipose tissue in attenuation and scattering correction in myocardial perfusion SPECT/CT: a phantom studyPublication . Guerreiro, B.; Pereira, P.; Rosa, R.; Valente, S.; Sousa, Eva; Almeida, P.; Branco, F.; Freixo, T.; Jonge, F. D.; Ferreira, T. C.; Vieira, LinaAssess the influence of thoracic AT on cardiac SPECT/CT counts, after attenuation correction and scatter correction.
- Análise de imagens de cintigrafia renal com um método de elementos finitosPublication . Vieira, Lina; Rodrigues, J. A.Objetivo do estudo: Avaliar a reprodutibilidade de um método variacional, discretizado por um método de elementos finitos, na análise de imagens de cintigrafia renal. Conclusões: A metodologia apresentada permite de forma automática obter resultados idênticos aos métodos tradicionais quanto à captação relativa renal, forma e ao número de pixeis.
- Anxiety in cancer patients during 18F-FDG PET/CT low dose: a comparison of anxiety levels before and after imaging studiesPublication . Grilo, Ana Monteiro; Vieira, Lina; Carolino, Elisabete; Oliveira, Cátia; Pacheco, Carolina; Castro, Maria; Alonso, JuanObjective - Assessing the level of anxiety in oncology patients who underwent (18)F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method - The study included 81 cancer patients submitted to the (18)F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI) before and after (18)F-FDG PET/CT low dose scan. Results - Substantial levels of anxiety were detected both before and after (18)F-FDG PET/CT low dose scan (STAI mean > 30), with a significant increase in the state of anxiety after scan performance (p < 0.0001, Medianpre = 31.1, and Medianpos = 33.0). (18)F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1%) and after (86.9%) the scan. The information provided by staff both before and on the (18)F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp.) and as very useful (70.5% and 72.6%, resp.) and correlated positively with patients' overall satisfaction with NM Department (rS = 0.372, p = 0.004 and rS = 0.528, p = 0.000, resp.), but not with anxiety levels. Conclusions - Patients perceive high levels of anxiety during the (18)F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction.
- Cardiac PET/CT with Rb-82: optimization of image acquisition and reconstruction parametersPublication . Chilra, P.; Gnesin, S.; Allenbach, G.; Monteiro, M.; Prior, J. O.; Vieira, Lina; Pires Jorge, J. A.Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in (82)Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Rest and stress list-mode dynamic (82)Rb PET acquisition data from 10 patients without myocardial flow defects and 10 patients with myocardial blood flow defects were reconstructed retrospectively. OSEM reconstructions were performed with Gaussian filters of 4, 6, and 8 mm, different iterations, and subset numbers (2 × 24; 2 × 16; 3 × 16; 4 × 16). Rest and stress global, regional, and segmental MBF and MFR were computed from time activity curves with FlowQuant(©) software. Left ventricular segmentation using the 17-segment American Heart Association model was obtained.
- Comparison between 3D laser scanning and computed tomography on the modelling of head surfacePublication . Sousa, Eva; Vieira, Lina; Costa, D. M.; Costa, Durval C.; Parafita, R.; Loja, M. A.The measurement of people physical parameters and proportions constitutes an important field of science, the anthropometry since it is related to the characterization of the human size and constitution; it allows improving the design and sizing of systems and devices to human use. To enable these measurements, different direct and indirect methodologies may be used depending on the particular aim of a specific study and on the eventual availability of data sources that can be used also for this purpose. Because of this relevance, the present work intends to assess the influence of different acquisition and reconstruction methods in the modeling of a 3D head surface. In order to assess the significance of the differences between acquisition and reconstruction methods, a set of measurements between several anatomic references of a physical phantom were carried out. Statistical evaluation using the Friedman test for non-parametrical pared samples was considered. We found, so far, no statistically significant differences between the several methods considered for acquisition and reconstruction.
- A comparison of two attenuation correction methods in 111In-Pentetriotide abdominal SPECTPublication . Costa, P. A.; Clemente, J. C.; Gonçalves, P. A.; Vieira, LinaTomographic image can be degraded, partially by patient based attenuation. The aim of this paper is to quantitatively verify the effects of attenuation correction methods Chang and CT in 111In studies through the analysis of profiles from abdominal SPECT, correspondent to a uniform radionuclide uptake organ, the left kidney.
- Contributo do ImageJ para segmentação do ventrículo esquerdo em cintigrafia de perfusão do miocárdioPublication . Sousa, Carlota Leonardo de; Carolino, Elisabete; Figueiredo, Sérgio; Vieira, LinaCintigrafia de perfusão do miocárdio - Aplicações clínicas: a)diagnóstico de doença arterial coronária (presença, localização e severidade); b) diagnóstico de enfarte agudo do miocárdio (mas só em repouso…); c) estratificação de risco (após-enfarte e pré-cirurgia); d) monitorização terapêutica após revascularização coronária (angioplastia ou CABG). Atualmente, existem vários softwares que permitem avaliar e quantificar a perfusão do miocárdio encontrando-se validados para uso na prática clínica. Objetivo do estudo - Avaliar a influência da aplicação de diferentes métodos de segmentação disponibilizados no ImageJ (threshold default, OTSU e k-means (k=2 e k=3), em CPM, em função da atividade administrada/simulada (275, 385, 500 e 750 Bequerel/voxel (Bq/voxel) no miocárdio.
- Developments on finite element methods for medical image supported diagnosticsPublication . Almeida, Ana; Barbosa, J. I.; Carvalho, A.; Loja, M. A. R.; Portal, R.; Rodrigues, J. A.; Vieira, LinaVariational image-processing models offer high-quality processing capabilities for imaging. They have been widely developed and used in the last two decades, enriching the fields of mathematics as well as information science. Mathematically, several tools are needed: energy optimization, regularization, partial differential equations, level set functions, and numerical algorithms. For this work we consider a second-order variational model for solving medical image problems. The aim is to obtain as far as possible fine features of the initial image and identify medical pathologies. The approach consists of constructing a regularized functional and to locally analyse the obtained solution. Some parameters selection is performed at the discrete level in the framework of the finite element method. We present several numerical simulations to test the efficiency of the proposed approach.
- Eficácia da música no controlo da ansiedade durante o exame de PET/TCPublication . Santos, Ana; Martins, Ana; Sousa, Carolina; Vieira, Lina; Grilo, Ana Monteiro; Carolino, Elisabete; Castro, Maria; Alonso, JuanIntrodução – Em exames de tomografia de emissão de positrões (PET, do acrónimo inglês Positron Emission Tomography) com tomografia computadorizada (TC) a ansiedade pode interferir com a experiência do paciente e até com o diagnóstico. A música tem vindo a ser utilizada para controlo da ansiedade dos pacientes em inúmeros contextos clínicos. Objetivo – Verificar o efeito da música no controlo da ansiedade dos pacientes durante exames PET/TC. Métodos – Estudo exploratório onde foram incluídos 22 pacientes no grupo de controlo (GC) e 23 no grupo experimental (GE) que realizaram exame de PET/TC com fluorodesoxiglucose marcada com flúor-18 (18F-FDG). Os pacientes do GE ouviram música durante a aquisição de imagens, enquanto os do GC não. Todos os pacientes responderam a questionários sobre a experiência do exame (QEE) e a uma versão reduzida do questionário State-Trait Anxiety Inventory-State (STAI-S) antes do exame (AE) e depois do exame (DE). Procedeu-se ainda à medição da pressão arterial sistólica (PAS) e diastólica (PAD) AE e DE. Resultados – Os valores do STAI-S não diferiram significativamente entre grupos, quer AE quer DE. Contudo, do AE para o DE verificou-se um aumento destes valores no GC e, em oposição, uma diminuição no GE. Comparando as PA entre o GE e o GC constatou-se que não existem diferenças significativas AE, mas existem DE, sendo que no GE os valores são inferiores aos do GC. No GE 91,3% dos pacientes relatou que a música é um auxílio durante o exame, classificando em média o nível de utilidade em 4,4 (0 a 5, sendo 5 o máximo). Conclusões – No presente estudo ouvir música parece ser eficaz no controlo da ansiedade em exames de PET/TC, mostrando-se os pacientes satisfeitos quanto à utilização desta técnica.