Percorrer por autor "Nogueira, Luísa"
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- Apparent diffusion coefficient in the analysis of prostate cancerPublication . Adubeiro, Nuno; Nogueira, Luísa; Ribeiro, Eduardo; Alves, Sandra; Ferreira, Hugo; La Fuente, JoséThe multiparametric magnetic resonance imaging (MPMRI) approach, has allowed the diagnostic performance in the detection and characterization of prostate cancer (PCa). Diffusion-weighted imaging (DWI), is an important technique in the MPMRI, that provides qualitative and quantitative biological information regarding water diffusivity in a non-invasive manner. The apparent diffusion coefficient (ADC) measures water mobility and can be quantified from the signal intensity loss between two or more b-values. Different studies reported that ADC values are directly associated with microvessel density and cellularity. One of the main aspects that is in discussion is the b-values that must be used in the DWI sequence in order to compute ADC.
- Application of the diffusion kurtosis model for the study of breast lesionsPublication . Nogueira, Luísa; Brandão, Sofia; Matos, Eduarda; Nunes, Rita Gouveia; Loureiro, Joana; Ramos, Isabel; Ferreira, Hugo AlexandreObjectives To evaluate diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) in the differentiation and characterisation of breast lesions. Methods Thirty-six women underwent breast magnetic resonance imaging (MRI) including a DWI sequence with multiple b-values (50–3,000 s/mm2). Mean values for apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) were calculated by lesion type and histological subtype. Differences and correlation between parameters were determined. Results Forty-four lesions were found. There were significant differences between benign and malignant lesions for all parameters (ADC, p = 0.017; MD, p = 0.028; MK, p = 0.017). ADC and MD were higher for benign (1.96 ± 0.41 × 10−3 and 2.17 ± 0.42 × 10−3 mm2/s, respectively) than for malignant lesions (1.33 ± 0.18 × 10−3 and 1.52 ± 0.50 × 10−3 mm2/s). MK was higher for malignant (0.61 ± 0.27) than benign lesions (0.37 ± 0.18). We found differences between invasive ductal carcinoma (IDC) and fibroadenoma (FA) for all parameters (ADC, MD and MK): p = 0.016, 0.022 and 0.016, respectively. FA and fibrocystic change (FC) showed differences only in MK (p = 0.016). Conclusions Diffusion in breast lesions follows a non-Gaussian distribution. MK enables differentiation and characterisation of breast lesions, providing new insights into microstructural complexity. To confirm these results, further investigation in a broader sample should be performed.
- Assessment of fat mass and fat-free mass in Portuguese adults: calibration of single-frequency leg-to-leg bioelectrical impedance with dual-energy x-ray absorptiometryPublication . Farias, Fernanda; Severo, Milton; Ramos, Elisabete; Lopes, Carla; Nogueira, Luísa; Araújo, Joana; Nogueira, LuisaBioelectrical impedance analysis (BIA) is more commonly employed in outpatient evaluations and epidemiological studies as it is cheaper and less time-consuming. Therefore, we aimed to compare fat mass (FM) and fat-free mass (FFM) estimated by BIA and dual-energy x-ray absorptiometry (DXA) in Portuguese adults, and to calibrate BIA estimates. We analyzed data from two population-based cohorts: EPIPorto (n = 391; <65 y) and EPITeen (n = 973; 27 y). Both completed single-frequency leg-to-leg BIA (Tanita TBF-300) and DXA (QDR 4500A Hologic). Agreement between BIA and DXA (FM/FFM) was evaluated by Bland and Altman. To calibrate the BIA estimates, the coefficients were estimated by linear regression using univariate (FM or FFM, separately) and multivariate models (FM and FFM in the same model). The correlation between BIA and DXA was high for FFM and for FM (FFM: r = 0.946/r = 0.954; FM: r = 0.926/r = 0.921, for EPIPorto and EPITeen, respectively). However, BIA underestimated FM (19.4% EPIPorto; 24.3% EPITeen) and overestimated FFM (11.3% EPIPorto; 14.4% EPITeen). Using the multivariate constrained model to have an absolute equal intercept for FFM and FM, the following calibration equations for BIA measurements were obtained for EPIPorto: FFMcalibrated =-5.119 + 0.995 £ FFMBIA;FMcalibrated = +5.119 + 0.980 £ FMBIA; and for EPITeen: FFMcalibrated =-5.707 + 0.984 £ FFMBIA;FMcalibrated = +5.707 + 0.975 £ FMBIA. FM assessed by single-frequency leg-to-leg BIA was largely underestimated and FFM overestimated in comparison to DXA, suggesting the use of BIA model-specific calibration equations to calibrate FM and FFMestimates in clinical settings and research studies.
- Associations between nutrition, energy expenditure and energy availability with bone mass acquisition in dance students: a 3-year longitudinal studyPublication . Amorim, Tânia; Freitas, Laura; Metsios, George S.; Thayse, Natacha Gomes; Wyon, Matthew; Flouris, Andreas D.; Maia, José; Marques, Franklim; Nogueira, Luísa; Adubeiro, Nuno; Koutedakis, YiannisThree years of study showed that female and male vocational dancers displayed lower bone mass compared to controls, at forearm, lumbar spine and femoral neck. Energy intake was found to positively predict bone mass accruals only in female dancers at femoral neck. Vocational dancers can be a risk population to develop osteoporosis.
- Avaliação radiológica do refluxo vesico – ureteral em criançasPublication . Nogueira, Luísa; Caldeira, J. P.; Adubeiro, NunoO Refluxo Vesico – Ureteral (RVU) é uma patologia frequente na idade pediátrica. A detecção precoce de RVU é fundamental na orientação terapêutica, de modo a permitir um crescimento renal adequado e prevenir infecções urinárias recorrentes. A investigação radiológica de RVU baseia-se na ecografia e cistouretrografia miccional seriada (CUMS), sendo este último procedimento, o método de eleição, efectuado sob controlo fluoroscópico. Este trabalho tem como objectivo dar a conhecer o papel CUMS na avaliação de RVU e abordar os parâmetros técnicos de aquisição, posicionamento e critérios de qualidade de imagem.
- Avanços da ressonância magnética mamária no diagnóstico do carcinoma da mamaPublication . Costa, Didier; Nogueira, Luísa; Ribeiro, EduardoA Ressonância Magnética Mamaria (RMM), ao longo da década, tem demonstrado um franco desenvolvimento no diagnóstico e caracterização do Carcinoma Mamário. O objectivo deste trabalho científico é demonstrar, através de uma revisão bibliográfica, os avanços desta modalidade na avaliação das lesões da mama, tendo em conta as características: elasticidade (Elastografia), bioquímicas (Espectroscopia), celularidade (Difusão) e vascularização (Perfusão). A avaliação destas em consonância com as morfológicas e cinéticas (RMM), permitem um aumento da especificidade da RMM, reduzindo assim o número de biopsias desnecessárias. Contudo estas evoluções técnicas devem estar em consonância com a inovação em questões de software de processamento de Imagem e hardware dos equipamentos de Ressonância Magnética.
- Changing slopes: can we be moving toward improved early treatment response prediction in breast cancer?Publication . Nogueira, Luísa; Adubeiro, Nuno; Nunes, Rita G.; Nogueira, LuisaBreast cancer is the most common malignant cancer among women worldwide. For locally advanced disease and selected early-stage cases of human epidermal growth factor receptor 2 (HER-2)-positive and triple-negative breast cancers (TNBC), neoadjuvant chemotherapy (NAC) is the standard of care. NAC reduces tumor burden, facilitates axillary surgery de-escalation, increases the feasibility of breast-conserving surgery and aims to achieve a pathological complete response (pCR). Attaining pCR after NAC is associated with improved disease-free and overall survival rates, providing valuable prognostic information.
- A colonoscopia virtual no rastreio do cancro colo rectalPublication . Guedes, Mónica; Barbosa, Simão; Nogueira, LuísaO cancro colo - rectal (CCR) é um problema de saúde mundial, estando associadas elevadas taxas de mortalidade e morbilidade. A maioria de CCR deriva de pólipos adenomatosos.. Um estudo retrospectivo, efectuado no serviço de Radiologia, dos achados imagiológicos típicos e atípicos, entre Janeiro de 2008 e Junho 2010. A Colonoscopia Virtual, apresenta uma sensibilidade elevada na detecção de lesões, com dimensão superior a 10mm, permitindo um diagnóstico precoce, é um exame rápido, pouco invasivo, não há necessidade de sedação e é efectuada em ambulatório.
- Detection of physiological changes in knee cartilage using parametric T2 relaxation maps estimated with a dictionary methodPublication . Coelho, José M.; Fernandes, Tiago T.; Alves, Sandra M.; Vilaça, Adélio; Nunes, Rita G.; Nogueira, Luísa; Oliveira, António; Nogueira, Luisa; Alves, Sandra MariaTo investigate half-marathon running and recovery effects on knee articular cartilage (KAC) health in athletes, using dictionary-matching T2 maps, to detect changes and recovery patterns in KAC. Eleven asymptomatic volunteers (4 females, 7 males; mean age 40 ± 5 years, mean BMI 22.7 ± 1.4 kg/m2) completed a fixed-pace half-marathonwere studied. All were right-knee dominant and engaged in regular running. Sagittal T2-weighted Multi-Echo Spin-Echo images at 3 T were used to assess T2 values pre-run, post-run, and one week later for global and compartmental KAC. Recovery programme included low-intensity running, strength training and rest. Repeated measures ANOVA or equivalent non-parametric tests with post-hoc comparisons compared T2 values over time. Separate analyses were conducted based on laterality, gender and anatomical compartments. Significance was set at < 0.05. Post-run T2 values decreased significantly by 0.9 ms (− 2.0%, p < 0.001), with up to 5.3% reductions in medial tibial (MT) and femoral (MF) compartments. Recovery patterns varied by compartment, sex and laterality. Most compartments returned to baseline within one week; the lateral condyle (LatC) showed incomplete recovery (− 4.7%, Proportional Recovery Index (PRI) = − 0,1); the right knee’s MT exhibited overcompensation (6.3%, PRI = 2.6). Males showed higher baseline T2 values and more efficient recovery in the LatC compared to females (PRI = − 0.1 vs. − 0.4). Half-marathon running induces reversible reductions in KAC hydration, with most compartments recovering or overcompensating within one week. Dictionary-matching T2 mapping offers a robust approach for monitoring cartilage integrity and guiding individualised recovery strategies.
- Diffusion-Weighted Breast Imaging: Beyond MorphologyPublication . Nogueira, Luísa; Nunes, Rita G.; Brandão, Sofia; Ramos, IsabelDiffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique that explores the molecular diffusivity of water in biological tissues to probe its microstructure. Its application to the study of breast lesions has been shown to improve their detection, characterization, and the diagnostic accuracy of breast lesions using MRI. In this chapter, the biophysical basis of diffusion is presented, including the model currently used for DWI in the clinical setting; the concept of apparent diffusion coefficient (ADC) is introduced. A theoretical framework of DWI in healthy conditions and in tissues affected by pathological processes is presented, followed by a literature review on the application of DWI to breast imaging. As the technique has only recently been used in breast imaging studies, controversial issues regarding its application have arisen, namely related to its technical challenges. Therefore, we detail the main technical issues associated with the implementation of DWI in the clinical setting and present potential approaches for obtaining good-quality images. Finally, we identify relevant future research needs involving hardware and software optimization as well as clinical issues which need to be addressed to improve breast lesion diagnosis.
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