Browsing by Author "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.
- 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.
- 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.
- Editorial for "Radiomics based on multimodal MRI for the differential diagnosis of benign and malignant breast lesions"Publication . Nogueira, Luisa; Nunes, R. G.Breast magnetic resonance imaging (MRI) is widely used to detect and characterize lesions, presenting good sensi- tivity but moderate specificity. To improve accuracy, new MRI sequences are continuously being sought. Diffusion- weighted imaging (DWI) probes the lesions’ cellularity, improving specificity. However, the distributions of the apparent diffusion coefficients (ADCs) for different lesion types show an overlap. Extensions to the monoexponential DWI model have thus been proposed such as diffusion- kurtosis imaging (DKI).
- Efeito e fatores preditivos da variação do glicerol sanguíneo induzido por eletrolipólise associada a exercício físico moderadoPublication . Couto, M; Noites, Andreia; Vilarinho, Rui; Melo, Cristina; Monteiro, Pedro; Moreira, A.; Cerqueira, Maria Manuela Amorim; Costa, D.; Adubeiro, Nuno; Nogueira, Luisa; Santos, RubimA acumulação de triglicerídeos no tecido adiposo abdominal acarreta risco acrescido para a saúde. Existem poucos estudos que demonstrem o efeito da eletrolipólise sobre o adipócito. A eletrolipólise poderá ser uma medida terapêutica coadjuvante ao exercício com o objectivo de potenciar a lipólise localizada. Assim torna-se pertinente reproduzir tais estudos, explorando se existem características individuais preditivas de mobilização lipolítica
- Endocrine parameters in association with bone mineral accrual in young female vocational ballet dancersPublication . Amorim, Tânia; Metsios, George S.; Flouris, Andreas D.; Nevill, Alan; Gomes, Thayse N.; Wyon, Matthew; Marques, Franklim; Nogueira, Luisa; Adubeiro, Nuno; Jamurtas, Athanasios Z.; Maia, José; Koutedakis, YiannisLess is known on bone mass gains in dancers involved in vocational dance training. The present study found that, as young vocational dancers progress on their professional training, their bone health remains consistently lower compared to non- exercising controls. Endocrine mechanisms do not seem to explain these findings.