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1.
J Biomech ; 71: 100-110, 2018 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-29454543

RESUMO

The mechanical characteristics of the female pelvic floor are relevant to understand pelvic floor dysfunctions (PFD), and how they are related with changes in their biomechanical behavior. Urinary incontinence (UI) and pelvic organ prolapse (POP) are the most common pathologies, which can be associated with changes in the mechanical properties of the supportive structures in the female pelvic cavity. PFD have been studied through different methods, from experimental tensile tests using tissues from fresh female cadavers or tissues collected at the time of a transvaginal hysterectomy procedure, or by applying imaging techniques. In this work, an inverse finite element analysis (FEA) was applied to understand the passive and active behavior of the pubovisceralis muscle (PVM) during Valsalva maneuver and muscle active contraction, respectively. Individual numerical models of women without pathology, with stress UI (SUI) and POP were built based on magnetic resonance images, including the PVM and surrounding structures. The passive and active material parameters obtained for a transversely isotropic hyperelastic constitutive model were estimated for the three groups. The values for the material constants were significantly higher for the women with POP when compared with the other two groups. The PVM of women with POP showed the highest stiffness. Additionally, the influence of these parameters was analyzed by evaluating their stress-strain, and force-displacements responses. The force produced by the PVM in women with POP was 47% and 82% higher when compared to women without pathology and with SUI, respectively. The inverse FEA allowed estimating the material parameters of the PVM using input information acquired non-invasively.


Assuntos
Fenômenos Mecânicos , Contração Muscular , Diafragma da Pelve/fisiologia , Prolapso de Órgão Pélvico/fisiopatologia , Incontinência Urinária por Estresse/fisiopatologia , Adolescente , Adulto , Idoso , Feminino , Análise de Elementos Finitos , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Diafragma da Pelve/diagnóstico por imagem , Prolapso de Órgão Pélvico/diagnóstico por imagem , Incontinência Urinária , Incontinência Urinária por Estresse/diagnóstico por imagem , Manobra de Valsalva , Adulto Jovem
2.
Comput Methods Biomech Biomed Engin ; 20(8): 842-852, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28303730

RESUMO

Pelvic disorders can be associated with changes in the biomechanical properties in the muscle, ligaments and/or connective tissue form fascia and ligaments. In this sense, the study of their mechanical behavior is important to understand the structure and function of these biological soft tissues. The aim of this study was to establish the biomechanical properties of the pelvic floor muscles of continent and incontinent women, using an inverse finite element analysis (FEA). The numerical models, including the pubovisceral muscle and pelvic bones were built from magnetic resonance (MR) images acquired at rest. The numerical simulation of Valsalva maneuver was based on the finite element method and the material constants were determined for different constitutive models (Neo-Hookean, Mooney-Rivlin and Yeoh) using an iterative process. The material constants (MPa) for Neo-Hookean (c1) were 0.039 ± 0.022 and 0.024 ± 0.004 for continent vs. incontinent women. For Mooney-Rivlin (c1) the values obtained were 0.026 ± 0.010 vs. 0.016 ± 0.003, and for Yeoh (c1) the values obtained were 0.031 ± 0.023 vs. 0.016 ± 0.002, (p < 0.05). Muscle displacements obtained in the numerical simulations of Valsalva maneuver were compared with the muscle displacements obtained through additional dynamic MRI. Incontinent women presented a higher antero-posterior displacement than the continent women. The results were also similar between MRI and numerical simulations (40.27% vs. 42.17% for Neo-Hookean, 39.87% for Mooney-Rivlin and 41.61% for Yeoh). Using an inverse FEA coupled with MR images allowed to obtain the in vivo biomechanical properties of the pelvic floor muscles, leading to a relationship between them for the continent and incontinent women in a non-invasive manner.


Assuntos
Análise de Elementos Finitos , Músculos/fisiopatologia , Diafragma da Pelve/fisiopatologia , Incontinência Urinária/fisiopatologia , Adulto , Fenômenos Biomecânicos , Simulação por Computador , Demografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Análise Numérica Assistida por Computador , Estresse Mecânico
4.
PLoS One ; 11(6): e0156688, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27257810

RESUMO

Movement is a key spatiotemporal process that enables interactions between animals and other elements of nature. The understanding of animal trajectories and the mechanisms that influence them at the landscape level can yield insight into ecological processes and potential solutions to specific ecological problems. Based upon optimal foraging models and empirical evidence, we hypothesized that movement by thrushes is highly tortuous (low average movement speeds and homogeneous distribution of turning angles) inside forests, moderately tortuous in urban areas, which present intermediary levels of resources, and minimally tortuous (high movement speeds and turning angles next to 0 radians) in open matrix types (e.g., crops and pasture). We used data on the trajectories of two common thrush species (Turdus rufiventris and Turdus leucomelas) collected by radio telemetry in a fragmented region in Brazil. Using a maximum likelihood model selection approach we fit four probability distribution models to average speed data, considering short-tailed, long-tailed, and scale-free distributions (to represent different regimes of movement variation), and one distribution to relative angle data. Models included land cover type and distance from forest-matrix edges as explanatory variables. Speed was greater farther away from forest edges and increased faster inside forest habitat compared to urban and open matrices. However, turning angle was not influenced by land cover. Thrushes presented a very tortuous trajectory, with many displacements followed by turns near 180 degrees. Thrush trajectories resembled habitat and edge dependent, tortuous random walks, with a well-defined movement scale inside each land cover type. Although thrushes are habitat generalists, they showed a greater preference for forest edges, and thus may be considered edge specialists. Our results reinforce the importance of studying animal movement patterns in order to understand ecological processes such as seed dispersal in fragmented areas, where the percentage of remaining habitat is dwindling.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Aves Canoras/fisiologia , Algoritmos , Animais , Biodiversidade , Brasil , Cidades , Feminino , Florestas , Geografia , Funções Verossimilhança , Masculino , Movimento , Probabilidade , Dispersão de Sementes , Telemetria , Temperatura , Árvores
5.
Proc Inst Mech Eng H ; 230(4): 298-309, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26867781

RESUMO

The mechanical characteristics of the female pelvic floor are relevant when explaining pelvic dysfunction. The decreased elasticity of the tissue often causes inability to maintain urethral position, also leading to vaginal and rectal descend when coughing or defecating as a response to an increase in the internal abdominal pressure. These conditions can be associated with changes in the mechanical properties of the supportive structures-namely, the pelvic floor muscles-including impairment. In this work, we used an inverse finite element analysis to calculate the material constants for the passive mechanical behavior of the pelvic floor muscles. The numerical model of the pelvic floor muscles and bones was built from magnetic resonance axial images acquired at rest. Muscle deformation, simulating the Valsalva maneuver with a pressure of 4 KPa, was compared with the muscle displacement obtained through additional dynamic magnetic resonance imaging. The difference in displacement was of 0.15 mm in the antero-posterior direction and 3.69 mm in the supero-inferior direction, equating to a percentage error of 7.0% and 16.9%, respectively. We obtained the shortest difference in the displacements using an iterative process that reached the material constants for the Mooney-Rivlin constitutive model (c10=11.8 KPa and c20=5.53 E-02 KPa). For each iteration, the orthogonal distance between each node from the group of nodes which defined the puborectal muscle in the numerical model versus dynamic magnetic resonance imaging was computed. With the methodology used in this work, it was possible to obtain in vivo biomechanical properties of the pelvic floor muscles for a specific subject using input information acquired non-invasively.


Assuntos
Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Diafragma da Pelve/diagnóstico por imagem , Diafragma da Pelve/fisiologia , Adulto , Fenômenos Biomecânicos/fisiologia , Feminino , Análise de Elementos Finitos , Humanos
6.
Ann Surg Oncol ; 22 Suppl 3: S985-91, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26314876

RESUMO

BACKGROUND: The American Joint Committee on Cancer (AJCC) stage III classification of oral cavity squamous cell carcinoma (OCSCC) represents a heterogeneous group of patients with early local disease with regional metastases (T1N1 and T2N1) and advanced local disease with or without regional metastasis (T3N0 and T3N1). OBJECTIVE: The aim of this study was to evaluate prognostic heterogeneity in the stage III category. METHODS AND PATIENTS: An international retrospective multicenter study of 1815 patients who were treated for OCSCC from 2003 to 2011. RESULTS: Kaplan-Meier survival analysis and multivariate models of stage III patients revealed better overall survival (OS; HR 2.12, 95 % CI 1.03-4.15; p = 0.01) and disease-specific survival (DSS; HR 1.7, 95 % CI 1.16-4.12; p = 0.04) rates for patients with T1-2N1/T3N0 disease than for patients with T3N1 disease. The outcomes of patients with T3N1 and stage IVa disease were similar (p = 0.89 and p = 0.78 for OS and DSS, respectively). Modifying stage classification by transferring the T3N1 category to the stage VIa group resulted in a better prognostic performance [Harrell's concordance index, C index 0.76; Akaike's Information Criterion (AIC) 4131.6] compared with the AJCC 7th edition staging system (C index 0.65; AIC 4144.9) for OS. When DSS was assessed, the suggested staging system remained the best performing model (C index 0.71; AIC 1061.3) compared with the current AJCC 7th edition staging (C index 0.64; AIC 1066.2). CONCLUSIONS: The prognosis of T3N1 and stage IVa disease are similar in OCSCC, suggesting that these categories could be combined in future revisions of the nodal staging system to enhance prognostic accuracy.


Assuntos
Carcinoma de Células Escamosas/patologia , Neoplasias Bucais/patologia , Estadiamento de Neoplasias/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/cirurgia , Feminino , Seguimentos , Humanos , Agências Internacionais , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/cirurgia , Invasividade Neoplásica , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Estados Unidos , Adulto Jovem
7.
J Dairy Sci ; 98(9): 6597-608, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26162790

RESUMO

Body condition scoring (BCS) is the most widely used method to assess changes in body fat reserves, which reflects its high potential to be included in on-farm welfare assessment protocols. Currently used scoring systems in dairy goats require animal restraint for body palpation. In this study, the Animal Welfare Indicators project (AWIN) proposes to overcome this constraint by developing a scoring system based only on visual assessment. The AWIN visual body condition scoring system highlights representative animals from 3 categories: very thin, normal, and very fat, and was built from data sets with photographs of animals scored by a commonly used 6-point scoring system that requires palpation in 2 anatomical regions. Development of the AWIN scoring system required 3 steps: (1) identification and validation of a body region of interest; (2) sketching the region from photographs; and (3) creation of training material. The scoring system's reliability was statistically confirmed. An initial study identified features in the rump region from which we could compute a set of body measurements (i.e., measures based on anatomical references of the rump region) that showed a strong correlation with the assigned BCS. To validate the result, we collected a final data set from 171 goats. To account for variability in animal size and camera position, we mapped a subset of features to a standard template and aligned all the rump images before computing the body measurements. Scientific illustrations were created from the aligned images of animals identified as representative of each category to increase clarity and reproducibility. For training material, we created sketches representing the threshold between consecutive categories. Finally, we conducted 2 field reliability studies. In the first test, no training was given to 4 observers, whereas in the second, training using the threshold images was delivered to the same observers. In the first experiment, interobserver results was substantial, showing that the visual scoring system is clear and unambiguous. Moreover, results improved after training, reaching almost perfect agreement for the very fat category. The visual body condition scoring system is not only a practical tool for BCS in dairy goats but also shows potential to be fully automated, which would enhance its use in welfare assessment schemes and farm management.


Assuntos
Tecido Adiposo , Tamanho Corporal , Bem-Estar do Animal , Animais , Composição Corporal , Feminino , Cabras , Modelos Lineares , Palpação , Reprodutibilidade dos Testes
8.
Br J Radiol ; 88(1051): 20140829, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25927876

RESUMO

OBJECTIVE: This article proposes a combination of californium-252 ((252)Cf) brachytherapy, boron neutron capture therapy (BNCT) and an intracavitary moderator balloon catheter applied to brain tumour and infiltrations. METHODS: Dosimetric evaluations were performed on three protocol set-ups: (252)Cf brachytherapy combined with BNCT (Cf-BNCT); Cf-BNCT with a balloon catheter filled with light water (LWB) and the same set-up with heavy water (HWB). RESULTS: Cf-BNCT-HWB has presented dosimetric advantages to Cf-BNCT-LWB and Cf-BNCT in infiltrations at 2.0-5.0 cm from the balloon surface. However, Cf-BNCT-LWB has shown superior dosimetry up to 2.0 cm from the balloon surface. CONCLUSION: Cf-BNCT-HWB and Cf-BNCT-LWB protocols provide a selective dose distribution for brain tumour and infiltrations, mainly further from the (252)Cf source, sparing the normal brain tissue. ADVANCES IN KNOWLEDGE: Malignant brain tumours grow rapidly and often spread to adjacent brain tissues, leading to death. Improvements in brain radiation protocols have been continuously achieved; however, brain tumour recurrence is observed in most cases. Cf-BNCT-LWB and Cf-BNCT-HWB represent new modalities for selectively combating brain tumour infiltrations and metastasis.


Assuntos
Terapia por Captura de Nêutron de Boro , Braquiterapia , Neoplasias Encefálicas/radioterapia , Cateterismo , Radiometria/métodos , Terapia por Captura de Nêutron de Boro/métodos , Braquiterapia/métodos , Califórnio , Cateterismo/métodos , Humanos , Imagens de Fantasmas , Dosagem Radioterapêutica
9.
Int J Sports Med ; 36(9): 776-80, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25875315

RESUMO

The purpose of this study was to determine the influence of different levels of regular physical exercise on the frequency of urinary incontinence in young nulliparous women from the northern region of Portugal. Participants (n=386) self-reported demographic variables, frequency, and time spent practicing organized exercise per week, as well as completed the International Consultation on Incontinence Questionnaire-Short Form. The level of exercise was calculated based on the time (in minutes) usually spent per week in organized exercise. 19.9% of Portuguese nulliparous women reported incontinence symptoms. Considering the distribution of urinary incontinence among the different quartiles of organized exercise, women from the 4(th)quartile (those who train for competitive purposes) demonstrated highest relative frequency (p=0.000) and a 2.53 greater relative risk to develop (95% CIs,1.3-2.7) incontinence compared to women from the 1(st) quartile (inactive). Women who practice exercise for recreational purposes (2(nd) and 3(rd) quartiles) did not show significant differences in the urinary incontinence prevalence and relative risk of developing it compared to women from the 1(st) quartile. The results showed that women participating in organized exercise involving high volume training for competition are potentially at risk of developing urinary incontinence, although organized exercise undertaken without the intent to compete seems to be safe for maintaining urinary continence.


Assuntos
Exercício Físico/fisiologia , Incontinência Urinária/epidemiologia , Adolescente , Adulto , Índice de Massa Corporal , Comportamento Competitivo/fisiologia , Estudos Transversais , Feminino , Humanos , Paridade , Educação Física e Treinamento , Portugal/epidemiologia , Prevalência , Fatores de Risco , Inquéritos e Questionários , Incontinência Urinária/etiologia , Adulto Jovem
10.
J Biomech ; 48(9): 1600-5, 2015 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-25757665

RESUMO

Pelvic floor injuries during vaginal delivery are considered a significant risk factor to develop pelvic floor dysfunction. The molding of the fetus head during vaginal delivery facilitates the labor progress, since it adjusts to the birth canal geometry. In this work, a finite element model was used to represent the effects induced by the passage of the fetus head on the pelvic floor. The numerical model used for this simulation included the pelvic floor muscles attached to the bones, and a fetus body. The model of the fetus head included the skin and soft tissues, the skull with sutures and fontanelles, and the brain. The fetus head movements during birth in vertex position were simulated: descent, internal rotation and extension. Two models of the fetus head were compared: a rigid and a deformable one, with the inclusion of the cranial sutures. The influence of the fetus head molding on the pelvic floor muscles was analyzed by evaluating their reaction forces, stretch, and stress and strain fields. Additionally, anatomical indices for the molding of the fetal skull were obtained and compared with clinical data. The passage of the deformable fetus head through the birth canal leads to a reduction of 17.3% on the reaction forces on the pelvic floor muscles when compared to the ones of a rigid head. Furthermore, the fetus head molding implies inferior resistance to rotation resulting in a reduction of 1.86% in muscle stretching. Quantitative evaluation of the fetus head molding showed good agreement with clinical experiments.


Assuntos
Feto/anatomia & histologia , Músculo Esquelético/fisiologia , Parto , Diafragma da Pelve/fisiologia , Fenômenos Biomecânicos , Simulação por Computador , Feminino , Análise de Elementos Finitos , Cabeça/anatomia & histologia , Humanos , Imageamento Tridimensional , Modelos Biológicos , Relaxamento Muscular , Gravidez
11.
J Sports Med Phys Fitness ; 55(11): 1272-6, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25359130

RESUMO

AIM: Sports are associated with pelvic floor dysfunction. This work aimed to assess, in nulliparous asymptomatic women, whether previous intense practice of high-impact sports is associated with differences in morphology and contraction of the pelvic floor muscles, when compared to women who practiced low-level physical activity. METHODS: In this prospective pilot study, 7 former high-impact sports practitioners and a control group (N.=7) were compared. Clinical evaluation and self-administered questionnaires were used to gather information about pelvic floor dysfunction and physical activity. Static and cine dynamic MR images were acquired. Morphological measures of the pubovisceral muscle area and thickness, and levator hiatus (LH) anterior-to-posterior diameter, width and area were taken in the static images. LH anterior-to-posterior diameter was again assessed in the dynamic acquisition (consecutive blocks of rest vs. maximal voluntary contraction). The relative variation between these two conditions was used as an indirect measure of contraction. RESULTS: No abnormal clinical or imaging findings were reported. Former high-impact sports practitioners evidenced decreased pubovisceral muscle thickness (right side P=0.005; left side P=0.004) and area (P=0.004), and larger levator hiatus width and area (P=0.045; P=0.005). Only its anterior-to-posterior diameter was similar (4.89cm±0.35 and 4.81cm±0.17, respectively). Their ability to perform maximum voluntary contractions seems to have decreased (8.03%±0.81 vs. 13.74%±0.95 for controls). CONCLUSION: The current results suggest that women who previously practiced high-impact sports, even being asymptomatic, may have suffered damage to the pelvic floor muscles due to the biomechanical impact of the sports. They may require pelvic floor muscle training to increase muscle thickness and hiatal closing capacity.


Assuntos
Atletas , Contração Muscular/fisiologia , Diafragma da Pelve/fisiologia , Adulto , Exercício Físico/fisiologia , Feminino , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Imagem Cinética por Ressonância Magnética/métodos , Distúrbios do Assoalho Pélvico/classificação , Projetos Piloto , Estudos Prospectivos , Esportes/fisiologia
12.
Transplant Proc ; 46(5): 1489-96, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24935318

RESUMO

Inconsistencies in cardiac rejection grading systems corroborate the concept that the evaluation of inflammatory intensity and myocyte damage seems to be subjective. We studied in 36 patients the potential role of the immunohistochemical (IHC) counting of inflammatory cells in endomyocardial biopsy (EMB) as an objective tool, testing the hypothesis of correlation between the International Society for Heart and Lung Transplantation 2004 rejection and IHC counting of inflammatory cells. We observed a progressive increment in CD68+ cells/mm(2) (P = .000) and CD3+ cells/mm(2) (P = .000) with higher rejection grade. A strong correlation between the grade of cellular rejection and both CD68+ cells/mm(2) and CD3+ cells/mm(2) was obtained (P = .000). One patient with CD3+ and CD68+ cells/mm(2) above the upper limit of the 95% confidence interval for cells/mm(2) found in rejection grade 1R evolved to rejection grade 2R without treatment. In patients with 2R that did not respond to treatment the values of CD68+ or CD3+ cells were higher than the overall median values for rejection grade 2R. For diagnosis of rejection needing treatment, the CD68+ and CD3+ cells/mm(2) areas under the receiver operating characteristic curves were 0.956 and 0.934, respectively. IHC counting of mononuclear inflammatory infiltrate in EMB seems to have additive potential role in evaluation of EMB for the diagnosis and prognosis of rejection episodes.


Assuntos
Antígenos CD/imunologia , Rejeição de Enxerto/diagnóstico , Transplante de Coração , Leucócitos Mononucleares/imunologia , Miocárdio/patologia , Adulto , Animais , Biópsia , Gatos , Feminino , Rejeição de Enxerto/metabolismo , Rejeição de Enxerto/patologia , Humanos , Imuno-Histoquímica , Masculino
13.
Br J Radiol ; 87(1039): 20130807, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24834475

RESUMO

OBJECTIVE: In 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 × 10(3)mm(2) 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) mm(2) 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) mm(2) 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). ADVANCES IN KNOWLEDGE: The best b-value pair for lesion discrimination and characterization through ADC quantification was 50, 1000 s mm(-2).


Assuntos
Neoplasias da Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Lobular/diagnóstico , Imagem de Difusão por Ressonância Magnética , Adulto , Idoso , Idoso de 80 Anos ou mais , Mama/patologia , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Lobular/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROC , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Manejo de Espécimes , Adulto Jovem
14.
Clin Radiol ; 69(4): 378-84, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24360516

RESUMO

AIM: To evaluate the performance of diffusion-weighted imaging (DWI) at 3 T for the detection and characterization of breast lesions. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) of the breast, including DWI single-shot spin-echo echo planar images (SS-SE-EPI; eight b-values, 50-3000 s/mm(2)), were acquired in women with a clinical indication for breast MRI. The exclusion criteria were as follows: (1) previous breast surgery, radiotherapy and/or chemotherapy within the prior 48 months (14 women); (2) only cystic lesions (one woman); (3) no detectable enhancing lesion at dynamic contrast-enhanced (DCE)-MRI (15 women); and (4) breast implants (four women). MRI results were corroborated by histopathology or imaging follow-up. Apparent diffusion coefficients (ADCs) were estimated for lesions and normal glandular tissue. Differences in the ADC between tissue types were evaluated and the sensitivity and specificity of the method calculated by receiver operating characteristics (ROC) curves. RESULTS: The final cohort comprised 53 patients with 59 lesions. Histopathology was obtained for 58 lesions. One lesion was validated as benign on imaging follow-up. Mean ADCs of 1.99 ± 0.27 × 10(-3) mm(2)/s, 1.08 ± 0.25 × 10(-3) mm(2)/s, and 1.74 ± 0.35 × 10(-3) mm(2)/s were obtained for normal tissue, malignant, and benign lesions, respectively. Mean ADCs of malignancies were significantly lower than those of benign lesions (p < 0.001) and normal tissue (p < 0.0001). The sensitivity and specificity for stratifying lesions, considering an ADC threshold of 1.41 × 10(-3) mm(2)/s, were 94.3% and 87.5%, respectively; accuracy was 91.5%. CONCLUSION: DWI proved useful for the detection and characterization of breast lesions in the present sample. ADC values provide a high diagnostic performance for differentiation between benign and malignant lesions.


Assuntos
Neoplasias da Mama/diagnóstico , Mama/patologia , Meios de Contraste , Imagem de Difusão por Ressonância Magnética , Detecção Precoce de Câncer , Gadolínio DTPA , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
15.
Br J Cancer ; 109(8): 2087-95, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24064974

RESUMO

BACKGROUND: Lymph node density (LND) has previously been reported to reliably predict recurrence risk and survival in oral cavity squamous cell carcinoma (OSCC). This multicenter international study was designed to validate the concept of LND in OSCC. METHODS: The study included 4254 patients diagnosed as having OSCC. The median follow-up was 41 months. Five-year overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), locoregional control and distant metastasis rates were calculated using the Kaplan-Meier method. Lymph node density (number of positive lymph nodes/total number of excised lymph nodes) was subjected to multivariate analysis. RESULTS: The OS was 49% for patients with LND0.07 compared with 35% for patients with LND>0.07 (P<0.001). Similarly, the DSS was 60% for patients with LND0.07 compared with 41% for those with LND>0.07 (P<0.001). Lymph node density reliably stratified patients according to their risk of failure within the individual N subgroups (P=0.03). A modified TNM staging system based on LND ratio was consistently superior to the traditional system in estimating survival measures. CONCLUSION: This multi-institutional study validates the reliability and applicability of LND as a predictor of outcomes in OSCC. Lymph node density can potentially assist in identifying patients with poor outcomes and therefore for whom more aggressive adjuvant treatment is needed.


Assuntos
Carcinoma de Células Escamosas/patologia , Linfonodos/patologia , Neoplasias Bucais/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/cirurgia , Estudos de Coortes , Intervalo Livre de Doença , Feminino , Humanos , Linfonodos/cirurgia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/cirurgia , Análise Multivariada , Metástase Neoplásica , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Taxa de Sobrevida , Adulto Jovem
16.
Clin Radiol ; 68(11): e617-23, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23932678

RESUMO

AIM: To compare T1-weighted (W) fat-water separation (Dixon's technique) with T1W fat-saturation (FS) and T2W Dixon with short-tau inversion recovery (STIR) images for fat suppression in a short-bore MRI machine. MATERIALS AND METHODS: Thirteen patients with lumbar disease were studied on using 1.5 T MRI machine. The protocol included T1 FS (with contrast medium administration) and/or STIR and T1W and/or T2W Dixon, for comparison. Three neuroradiologists scored the images from the two-pairs of techniques for fat suppression uniformity and lesion conspicuity. Clinical usefulness of fat-only images was also evaluated. RESULTS: Regarding uniformity of fat suppression, mean scores were 2.28 (±0.49), 3.06 (±0.49), 2.39 (±0.49), and 3.15 (±0.35) for T1W FS, T1W Dixon, STIR, and T2W Dixon sequences, respectively. For the same pulse sequences, lesion conspicuity scores were 2.78 (±0.50), 2.78 (±0.27), 2.76 (±0.47), and 2.91 (±0.4), respectively. Both T1W and T2W Dixon sequences showed more homogeneous fat-suppression when compared to T1W FS (p = 0.026) and STIR (p = 0.008) techniques, but no significant difference was found for lesion conspicuity. Mean scores for the diagnostic utility of fat-only maps were, respectively, 1.72 (±0.39) and 2.48 (±0.50) for T1W and T2W Dixon. CONCLUSION: Fat suppression quality was superior with Dixon when compared to the conventional sequences, but not lesion conspicuity, suggesting that both techniques are reliable for diagnosis. Dixon may be advantageous in cases where inhomogeneity artefacts are an issue. Water-only maps appear to be useful in the clinical setting.


Assuntos
Degeneração do Disco Intervertebral/diagnóstico , Deslocamento do Disco Intervertebral/diagnóstico , Vértebras Lombares/patologia , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Gadolínio , Humanos , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Prospectivos , Reprodutibilidade dos Testes , Adulto Jovem
17.
Ann Surg Oncol ; 20(11): 3575-81, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23775408

RESUMO

BACKGROUND: We aimed to study the importance of clinical N classification (cN) in a subgroup of patients with oral cavity squamous cell carcinoma (OSCC) and pathologically negative neck nodes (pN-). METHODS: A total of 2,258 patients from 11 cancer centers who underwent neck dissection for OSCC (1990-2011) had pN- disease. The median follow-up was 44 months. 5-year overall survival (OS), disease-specific survival (DSS), disease free survival, local control, locoregional control, and distant metastasis rates were calculated by the Kaplan-Meier method. cN classification and tumor, node, metastasis classification system staging variables were subjected to multivariate analysis. RESULTS: A total of 345 patients were preoperatively classified as cN+ and 1,913 were classified as cN-. The 5-year OS and DSS of cN- patients were 73.6 and 82.2 %, respectively. The 5-year OS and DSS of cN+ patients were 64.9 and 76.9 %, respectively (p < 0.0001 each). A cN+ classification was a significant predictor of worse OS (p = 0.03) and DSS (p = 0.016), regardless of treatment, depth of invasion, or extent of neck dissection. cN classification was associated with recurrence-free survival (p = 0.01) and locoregional (neck and primary tumor) control (p = 0.004), but not with local (p = 0.19) and distant (p = 0.06) recurrence rates. CONCLUSIONS: Clinical evidence of neck metastases is an independent predictor of outcome, even in patients with pN- nodes.


Assuntos
Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/secundário , Linfonodos/patologia , Neoplasias Bucais/mortalidade , Neoplasias Bucais/patologia , Esvaziamento Cervical/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Agências Internacionais , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
18.
J Indian Assoc Pediatr Surg ; 17(3): 104-6, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22869974

RESUMO

AIM: In children suffering from severe hepatosplenic schistosomiasis, the surgical protocol includes splenectomy and autoimplantation of spleen morsels in the major omentum, which has the potential of reducing the overwhelming postsplenectomy infection (OPSI). The purpose of the study was to evaluate the remaining splenosis, with the mean postoperative followup of 12.1 ± 5.6 years; to compare the efficacy of the 2 evaluation tools. MATERIALS AND METHODS: Nineteen patients underwent, when they were children, portal decompression and autoimplantation of spleen. After a mean age of 23.4 ± 5.3 years, they were investigated regarding the number of infections and OPSI. They had undergone hepatosplenic scintigraphy with labeled colloidal SnTc(99m) and abdominal ultrasound. It was considered efficient splenosis when the patients presented with 5 or more spleen nodules. The evaluation was performed by 3 observers. RESULTS: None of the patients had increased infection rate or developed OPSI. Sixteen (84.2%) presented efficient splenosis. CONCLUSIONS: The remaining postoperative splenosis was considered efficient in the majority of patients in the long-term followup; and nuclear medicine was considered the gold standard for splenosis evaluation.

19.
Braz J Med Biol Res ; 43(3): 297-302, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20209376

RESUMO

Patients with metabolic syndrome are at high-risk for development of atherosclerosis and cardiovascular events. The objective of this study was to examine the major determinants of coronary disease severity, including those coronary risk factors associated with metabolic syndrome, during the early period after an acute coronary episode. We tested the hypothesis that inflammatory markers, especially highly sensitive C-reactive protein (hsCRP), are related to coronary atherosclerosis, in addition to traditional coronary risk factors. Subjects of both genders aged 30 to 75 years (N = 116) were prospectively included if they had suffered a recent acute coronary syndrome (acute myocardial infarction or unstable angina pectoris requiring hospitalization) and if they had metabolic syndrome diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III. Patients were submitted to a coronary angiography and the burden of atherosclerosis was estimated by the Gensini score. The severity of coronary disease was correlated (Spearman's or Pearson's coefficient) with gender (r = 0.291, P = 0.008), age (r = 0.218, P = 0.048), hsCRP (r = 0.256, P = 0.020), ApoB/ApoA ratio (r = 0.233, P = 0.041), and carotid intima-media thickness (r = 0.236, P = 0.041). After multiple linear regression, only male gender (P = 0.046) and hsCRP (P = 0.012) remained independently associated with the Gensini score. In this high-risk population, male gender and high levels of hsCRP, two variables that can be easily obtained, were associated with more extensive coronary disease, identifying patients with the highest potential of developing new coronary events.


Assuntos
Síndrome Coronariana Aguda/sangue , Proteína C-Reativa/metabolismo , Síndrome Metabólica/sangue , Índice de Gravidade de Doença , Síndrome Coronariana Aguda/etiologia , Adulto , Idoso , Biomarcadores/sangue , Angiografia Coronária , Feminino , Humanos , Masculino , Síndrome Metabólica/complicações , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Sensibilidade e Especificidade , Fatores Sexuais
20.
Braz. j. med. biol. res ; 43(3): 297-302, Mar. 2010. tab
Artigo em Inglês | LILACS | ID: lil-539717

RESUMO

Patients with metabolic syndrome are at high-risk for development of atherosclerosis and cardiovascular events. The objective of this study was to examine the major determinants of coronary disease severity, including those coronary risk factors associated with metabolic syndrome, during the early period after an acute coronary episode. We tested the hypothesis that inflammatory markers, especially highly sensitive C-reactive protein (hsCRP), are related to coronary atherosclerosis, in addition to traditional coronary risk factors. Subjects of both genders aged 30 to 75 years (N = 116) were prospectively included if they had suffered a recent acute coronary syndrome (acute myocardial infarction or unstable angina pectoris requiring hospitalization) and if they had metabolic syndrome diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III. Patients were submitted to a coronary angiography and the burden of atherosclerosis was estimated by the Gensini score. The severity of coronary disease was correlated (Spearman’s or Pearson’s coefficient) with gender (r = 0.291, P = 0.008), age (r = 0.218, P = 0.048), hsCRP (r = 0.256, P = 0.020), ApoB/ApoA ratio (r = 0.233, P = 0.041), and carotid intima-media thickness (r = 0.236, P = 0.041). After multiple linear regression, only male gender (P = 0.046) and hsCRP (P = 0.012) remained independently associated with the Gensini score. In this high-risk population, male gender and high levels of hsCRP, two variables that can be easily obtained, were associated with more extensive coronary disease, identifying patients with the highest potential of developing new coronary events.


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Coronariana Aguda/sangue , Proteína C-Reativa/metabolismo , Síndrome Metabólica/sangue , Índice de Gravidade de Doença , Síndrome Coronariana Aguda/etiologia , Biomarcadores/sangue , Angiografia Coronária , Síndrome Metabólica/complicações , Estudos Prospectivos , Fatores de Risco , Sensibilidade e Especificidade , Fatores Sexuais
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