Percorrer por autor "Nogueira, Luisa"
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- Acute effects of physical exercise with microcurrent in the adipose tissue of the abdominal region: A randomized controlled trialPublication . Noites, Andreia; Moreira, Anabela; Melo, Cristina; Faria, Miriam; Vilarinho, Rui; Freitas, Carla; Monteiro, Pedro; Carvalho, Paulo; Adubeiro, Nuno; Sousa, Maria; Santos, Rubim; Nogueira, LuisaIncreased abdominal fat and sedentary lifestyles contribute to cardiovascular disease risk. Low-intensity electrical current (microcurrent) on the abdominal region, associated with physical exercise, appears to be an innovative method to increase the lipolytic rate of abdominal adipocytes, in order to reduce abdominal fat. This study aimed to analyze the acute effects of microcurrent associated with an aerobic exercise program in healthy subjects in lipolysis. A double-blinded, randomized controlled trial was developed and conducted in a higher education school. Eighty-three healthy subjects, aged between 18 and 30 years old and with a 18.5 to 29.9 kg/m2 body mass index were randomly assigned either to an experimental or to a placebo group. Subjects received a trans-abdominal microcurrent stimulation for 40 min with (experimental group) or without (placebo group) electrical current, followed by a single aerobic exercise session (60 min at 45–55% VO2max intensity). Lipolytic activity (serum glycerol), abdominal fat (waist circumference, abdominal skinfold, ultrasonography), and serum lipid profile (serum triglyceride, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol) were evaluated in all subjects. Physical activity (International Physical Activity Questionnaire) and dietary intake (food-frequency questionnaire) questionnaires were applied. After the intervention, lipolytic rate was significantly higher (p = 0.003) in the experimental group (mean = 0.15) than in the placebo group (mean = 0.09). Glycerol results showed a statistically significant increase between baseline and after the intervention for both experimental group (p = 0.001) and the placebo group (p = 0.001). Combined use of microcurrent and physical aerobic exercise had an acute effect enhancing lipolytic rate comparing to exercise alone, in young healthy subjects.
- 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.
- Body mass index and visceral fat: correlation with serum lipid profile in healthy young adultsPublication . Moreira, Anabela; Noites, Andreia; Couto, Miriam; Vilarinho, Rui; Melo, Cristina; Sousa, Manuela; Monteiro, Pedro; Carvalho, Paulo; Adubeiro, Nuno; Nogueira, Luisa; Santos, RubimMetabolic and cardiovascular complications and obesity association is well described. Body mass index (BMI) is commonly used to assess obesity, but does not reflect body fat distribution. Abdominal obesity, namely visceral adipose tissue (VAT), is associated with greater risk for those metabolic impairments, including dyslipidemia, than adiposity in other regions of the body. Objective: To determine the correlation between serum lipid profile and anthropometric measures (BMI and VAT) in young healthy adults.
- Breast DWI at 3 T: influence of the fat-suppression technique on image quality and diagnostic performancePublication . Nogueira, Luisa; Brandão, Sofia; Nunes, Rita G.; Ferreira, Hugo Alexandre; Loureiro, Joana; Ramos, IsabelAim To evaluate two fat-suppression techniques: short tau inversion recovery (STIR) and spectral adiabatic inversion recovery (SPAIR) regarding image quality and diagnostic performance in diffusion-weighted imaging (DWI) of breast lesions at 3 T. Materials and methods Ninety-two women (mean age 48 ± 12.1 years; range 21–78 years) underwent breast MRI. Two DWI pulse sequences, with b-values (50 and 1000 s/mm2) were performed with STIR and SPAIR. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), suppression homogeneity, and apparent diffusion coefficient (ADC) values were quantitatively assessed for each technique. Values were compared between techniques and lesion type. Receiver operating characteristics (ROC) analysis was used to evaluate lesion discrimination. Results One hundred and fourteen lesions were analysed (40 benign and 74 malignant). SNR and CNR were significantly higher for DWI-SPAIR; fat-suppression uniformity was better for DWI-STIR (p < 1 × 10−4). ADC values for benign and malignant lesions and normal tissue were 1.92 × 10−3, 1.18 × 10−3, 1.86 × 10−3 s/mm2 for DWI-STIR and 1.80 × 10−3, 1.11 × 10−3, 1.79 × 10−3 s/mm2 for SPAIR, respectively. Comparison between fat-suppression techniques showed significant differences in mean ADC values for benign (p = 0.013) and malignant lesions (p = 0.001). DWI-STIR and -SPAIR ADC cut-offs were 1.42 × 10−3 and 1.46 × 10−3 s/mm2, respectively. Diagnostic performance for DWI-STIR versus SPAIR was: accuracy (81.6 versus 83.3%), area under curve (87.7 versus 89.2%), sensitivity (79.7 versus 85.1%), and specificity (85 versus 80%). Positive predictive value was similar. Conclusion The fat-saturation technique used in the present study may influence image quality and ADC quantification. Nevertheless, STIR and SPAIR techniques showed similar diagnostic performances, and therefore, both are suitable for use in clinical practice.
- Central and peripheral body fat distribution: Different associations with low-grade inflammation in young adults?Publication . Cabral, Maria Bangdiwala; Bangdiwala, Shrikant I.; Severo, Milton; Guimarães, João T.; Nogueira, Luisa; Ramos, ElisabeteBackground and aimsEvidence regarding the impact of regional body fat distribution on low-grade inflammation is limited. The current study examined the association of central and peripheral body fat distribution and low-grade inflammation levels in young adults, considering collinearity between variables.
- 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.
- 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 MRI outside the brainPublication . Nunes, Rita G.; Nogueira, Luisa; Gaspar, Andreia S.; Adubeiro, Nuno; Brandão, SofiaThis manuscript provides an overview of recent developments in Diffusion-Weighted Imaging (DWI) outside the brain, focusing on liver, breast, prostate, muskuloskeletal (MSK) and cardiac applications. A general introduction to cross-cutting acquisition and image processing challenges is first provided. These often include short T2 relaxation times, the need to image a large field-of-view with the resulting complications in shimming the B0 field and achieving good fat suppression. Some of the strategies developed for dealing with motion, namely cardiac and respiratory motion are described. Specific sections are then presented for each of the aforementioned organs. A motivation for the clinical applicability of DWI is first provided, followed by specific image acquisition and processing considerations. Quantitative imaging is becoming standard in clinical practice, and the Apparent Diffusion Coefficient is routinely estimated in the liver, breast and prostate. Application of alternative signal models in these organs is being explored, including both the Intravoxel Incoherent Motion and Diffusion Kurtosis models. Ongoing efforts are focused on evaluating the potential clinical added value of the extra parameters and on improving their repeatability. MSK and cardiac DWI have shown potential for assessing pathological changes in fiber architecture, but further validation is required to enable application in the clinical setting.
- Diffusion-weighted breast imaging at 3 T: Preliminary experiencePublication . Nogueira, Luisa; Brandão, S.; Matos, E.; Nunes, R. G.; Ferreira, H. A.; Loureiro, J.; Ramos, I.To evaluate the performance of diffusion-weighted imaging (DWI) at 3 T for the detection and characterization of breast lesions.
- Diffusion-weighted imaging: determination of the best pair ofb-values to discriminate breast lesionsPublication . Nogueira, Luisa; Brandão, S; Matos, E; Nunes, R G; Loureiro, J; Ferreira, H A; Ramos, IIn breast diffusion-weighted imaging (DWI), the apparent diffusion coefficient (ADC) is used to discriminate between malignant and benign lesions. As ADC estimates can be affected by the weighting factors, our goal was to determine the optimal pair of b-values for discriminating breast lesions at 3.0 T. METHODS: 152 females with 157 lesions (89 malignant and 68 benign) underwent breast MRI, including a DWI sequence sampling six b-values 50, 200, 400, 600, 800 and 1000 s mm−2. ADC values were computed from different pairs of b-values and compared with ADC obtained by fitting the six b-values using a mono-exponential diffusion model (ADCall). Cut-off ADC values were determined and diagnostic performance evaluated by receiver operating characteristic analysis using Youden statistics. Mean ADCs were determined for normal tissue and lesions. Differences were evaluated by lesion and histological types. RESULTS: Considering the cut-off values 1.46 and 1.49 × 103mm2 s−1, the pairs 50, 1000 and 200, 800 s mm−2 showed the highest accuracy, 77.5% and 75.4% with areas under the curve 84.4% and 84.2%, respectively. The best pair for ADC quantification was 50, 1000 s mm−2 with 38/49 true-negative and 69/89 true-positive cases respectively; mean ADCs were 1.86 ± 0.46, 1.77 ± 0.37 and 1.15 ± 0.46 × 10−3 mm2 s−1 for normal, benign and malignant lesions. There were no significant differences in these ADC values when compared with ADCall (ADC calculated from the full set of b - values) [difference = 0.0075 × 10−3 mm2 s−1; confidence interval 95%: (−0.0036; 0.0186); p = 0.18]. CONCLUSION: The diagnostic performance in differentiating malignant and benign lesions was most accurate for the b-value pair 50, 1000 s mm−2.