Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Eur J Cancer Prev ; 30(6): 423-430, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34545020

RESUMO

BACKGROUND AND AIMS: The overall evidence on the association between gallbladder conditions (GBC: gallstones and cholecystectomy) and pancreatic cancer (PC) is inconsistent. To our knowledge, no previous investigations considered the role of tumour characteristics on this association. Thus, we aimed to assess the association between self-reported GBC and PC risk, by focussing on timing to PC diagnosis and tumour features (stage, location, and resection). METHODS: Data derived from a European case-control study conducted between 2009 and 2014 including 1431 PC cases and 1090 controls. We used unconditional logistic regression models to estimate odds ratios (ORs) and corresponding 95% confidence intervals (CIs) adjusted for recognized confounders. RESULTS: Overall, 298 (20.8%) cases and 127 (11.6%) controls reported to have had GBC, corresponding to an OR of 1.70 (95% CI 1.33-2.16). The ORs were 4.84 (95% CI 2.96-7.89) for GBC diagnosed <3 years before PC and 1.06 (95% CI 0.79-1.41) for ≥3 years. The risk was slightly higher for stage I/II (OR = 1.71, 95% CI 1.15-2.55) vs. stage III/IV tumours (OR = 1.23, 95% CI 0.87-1.76); for tumours sited in the head of the pancreas (OR = 1.59, 95% CI 1.13-2.24) vs. tumours located at the body/tail (OR = 1.02, 95% CI 0.62-1.68); and for tumours surgically resected (OR = 1.69, 95% CI 1.14-2.51) vs. non-resected tumours (OR = 1.25, 95% CI 0.88-1.78). The corresponding ORs for GBC diagnosed ≥3 years prior PC were close to unity. CONCLUSION: Our study supports the association between GBC and PC. Given the time-risk pattern observed, however, this relationship may be non-causal and, partly or largely, due to diagnostic attention and/or reverse causation.


Assuntos
Doenças da Vesícula Biliar , Neoplasias da Vesícula Biliar , Neoplasias Pancreáticas , Estudos de Casos e Controles , Doenças da Vesícula Biliar/cirurgia , Neoplasias da Vesícula Biliar/diagnóstico , Neoplasias da Vesícula Biliar/epidemiologia , Neoplasias da Vesícula Biliar/etiologia , Humanos , Modelos Logísticos , Pâncreas/patologia , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/epidemiologia , Neoplasias Pancreáticas/etiologia , Fatores de Risco , Neoplasias Pancreáticas
2.
J Public Health (Oxf) ; 40(suppl_1): i31-i38, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29538725

RESUMO

Background: In 2008, five UKCRC Public Health Research Centres of Excellence were created to develop a coordinated approach to policy and practice engagement and knowledge exchange. The five Centres have developed their own models and practices for achieving these aims, which have not been compared in detail to date. Methods: We applied an extended version of Saner's model for the interface between science and policy to compare five case studies of knowledge exchanges, one from each centre. We compared these practices on three dimensions within our model (focus, function and type/scale) to identify barriers and facilitators for knowledge exchange. Results: The case studies shared commonalities in their range of activities (type) but illustrated different ways of linking these activities (function). The Centres' approaches ranged from structural to more organic, and varied in the extent that they engaged internal audiences (focus). Each centre addressed policymakers at different geographical levels and scale. Conclusions: This article emphasizes the importance of linking a range of activities that engage policymakers at different levels, intensities and points in their decision-making processes to build relationships. Developing a structural approach to knowledge exchange activities in different contexts presents challenges of resource, implementation and evaluation.


Assuntos
Troca de Informação em Saúde , Prática de Saúde Pública , Humanos , Pesquisa Translacional Biomédica
3.
Int J Epidemiol ; 47(2): 473-483, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29329392

RESUMO

Background: Family history (FH) of pancreatic cancer (PC) has been associated with an increased risk of PC, but little is known regarding the role of inherited/environmental factors or that of FH of other comorbidities in PC risk. We aimed to address these issues using multiple methodological approaches. Methods: Case-control study including 1431 PC cases and 1090 controls and a reconstructed-cohort study (N = 16 747) made up of their first-degree relatives (FDR). Logistic regression was used to evaluate PC risk associated with FH of cancer, diabetes, allergies, asthma, cystic fibrosis and chronic pancreatitis by relative type and number of affected relatives, by smoking status and other potential effect modifiers, and by tumour stage and location. Familial aggregation of cancer was assessed within the cohort using Cox proportional hazard regression. Results: FH of PC was associated with an increased PC risk [odds ratio (OR) = 2.68; 95% confidence interval (CI): 2.27-4.06] when compared with cancer-free FH, the risk being greater when ≥ 2 FDRs suffered PC (OR = 3.88; 95% CI: 2.96-9.73) and among current smokers (OR = 3.16; 95% CI: 2.56-5.78, interaction FHPC*smoking P-value = 0.04). PC cumulative risk by age 75 was 2.2% among FDRs of cases and 0.7% in those of controls [hazard ratio (HR) = 2.42; 95% CI: 2.16-2.71]. PC risk was significantly associated with FH of cancer (OR = 1.30; 95% CI: 1.13-1.54) and diabetes (OR = 1.24; 95% CI: 1.01-1.52), but not with FH of other diseases. Conclusions: The concordant findings using both approaches strengthen the notion that FH of cancer, PC or diabetes confers a higher PC risk. Smoking notably increases PC risk associated with FH of PC. Further evaluation of these associations should be undertaken to guide PC prevention strategies.


Assuntos
Neoplasias Pancreáticas/epidemiologia , Fumar/efeitos adversos , Adulto , Idoso , Estudos de Casos e Controles , Estudos de Coortes , Diabetes Mellitus/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Modelos Logísticos , Masculino , Anamnese , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Neoplasias Pancreáticas/genética , Medição de Risco , Fatores de Risco
4.
Ann Oncol ; 28(7): 1618-1624, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28383714

RESUMO

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is usually diagnosed in late adulthood; therefore, many patients suffer or have suffered from other diseases. Identifying disease patterns associated with PDAC risk may enable a better characterization of high-risk patients. METHODS: Multimorbidity patterns (MPs) were assessed from 17 self-reported conditions using hierarchical clustering, principal component, and factor analyses in 1705 PDAC cases and 1084 controls from a European population. Their association with PDAC was evaluated using adjusted logistic regression models. Time since diagnosis of morbidities to PDAC diagnosis/recruitment was stratified into recent (<3 years) and long term (≥3 years). The MPs and PDAC genetic networks were explored with DisGeNET bioinformatics-tool which focuses on gene-diseases associations available in curated databases. RESULTS: Three MPs were observed: gastric (heartburn, acid regurgitation, Helicobacter pylori infection, and ulcer), metabolic syndrome (obesity, type-2 diabetes, hypercholesterolemia, and hypertension), and atopic (nasal allergies, skin allergies, and asthma). Strong associations with PDAC were observed for ≥2 recently diagnosed gastric conditions [odds ratio (OR), 6.13; 95% confidence interval CI 3.01-12.5)] and for ≥3 recently diagnosed metabolic syndrome conditions (OR, 1.61; 95% CI 1.11-2.35). Atopic conditions were negatively associated with PDAC (high adherence score OR for tertile III, 0.45; 95% CI, 0.36-0.55). Combining type-2 diabetes with gastric MP resulted in higher PDAC risk for recent (OR, 7.89; 95% CI 3.9-16.1) and long-term diagnosed conditions (OR, 1.86; 95% CI 1.29-2.67). A common genetic basis between MPs and PDAC was observed in the bioinformatics analysis. CONCLUSIONS: Specific multimorbidities aggregate and associate with PDAC in a time-dependent manner. A better characterization of a high-risk population for PDAC may help in the early diagnosis of this cancer. The common genetic basis between MP and PDAC points to a mechanistic link between these conditions.


Assuntos
Carcinoma Ductal Pancreático/epidemiologia , Biologia Computacional , Neoplasias Pancreáticas/epidemiologia , Análise de Sistemas , Biologia de Sistemas , Biomarcadores Tumorais/genética , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/genética , Estudos de Casos e Controles , Análise por Conglomerados , Comorbidade , Bases de Dados Genéticas , Europa (Continente)/epidemiologia , Análise Fatorial , Humanos , Modelos Logísticos , Análise Multivariada , Razão de Chances , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Análise de Componente Principal , Medição de Risco , Fatores de Risco , Fatores de Tempo
5.
Cancer Treat Rev ; 47: 12-21, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27214603

RESUMO

BACKGROUND: The value of adjuvant radiotherapy in triple negative breast cancer (TNBC) remains unclear. A systematic review and meta-analysis was conducted in TNBC patients to assess survival and recurrence outcomes associated with radiotherapy following either breast conserving therapy (BCT) or post-mastectomy radiotherapy (PMRT). METHODS: Four electronic databases were searched from January 2000 to November 2015 (PubMed, MEDLINE, EMBASE and Web of Science). Studies investigating overall survival and/or recurrence in TNBC patients according to radiotherapy administration were included. A random effects meta-analysis was conducted using mastectomy only patients as the reference. RESULTS: Twelve studies were included. The pooled hazard ratio (HR) for locoregional recurrence comparing BCT and PMRT to mastectomy only was 0.61 (95% confidence interval [CI] 0.41-0.90) and 0.62 (95% CI 0.44-0.86), respectively. Adjuvant radiotherapy was not significantly associated with distant recurrence. The pooled HR for overall survival comparing BCT and PMRT to mastectomy only was 0.57 (95% CI 0.36-0.88) and HR 1.12 (95% CI 0.75, 1.69). Comparing PMRT to mastectomy only, tests for interaction were not significant for stage (p=0.98) or age at diagnosis (p=0.85). However, overall survival was improved in patients with late-stage disease (T3-4, N2-3) pooled HR 0.53 (95% CI 0.32-0.86), and women <40years, pooled HR 0.30 (95% CI 0.11-0.82). CONCLUSIONS: Adjuvant radiotherapy was associated with a significantly lower risk of locoregional recurrence in TNBC patients, irrespective of the type of surgery. While radiotherapy was not consistently associated with an overall survival gain, benefits may be obtained in women with late-stage disease and younger patients.


Assuntos
Neoplasias de Mama Triplo Negativas/mortalidade , Neoplasias de Mama Triplo Negativas/radioterapia , Feminino , Humanos , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/prevenção & controle , Modelos de Riscos Proporcionais , Radioterapia Adjuvante , Análise de Sobrevida , Neoplasias de Mama Triplo Negativas/cirurgia
6.
Cancer Causes Control ; 26(3): 355-66, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25534917

RESUMO

PURPOSE: Pre-clinical studies suggest that oral anticoagulant agents, such as warfarin, may inhibit metastases and potentially prolong survival in cancer patients. However, few population-based studies have examined the association between warfarin use and cancer-specific mortality. METHODS: Using prescribing, cause of death, and cancer registration data from the UK Clinical Practice Research Datalink, four population-based cohorts were constructed, comprising breast, colorectal, lung, and prostate cancer patients diagnosed between 1 January 1998, and the 31 December 2010. Comparing pre-diagnostic warfarin users to non-users, multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for cancer-specific mortality. RESULTS: Overall, 16,525 breast, 12,902 colorectal, 12,296 lung, and 12,772 prostate cancers were included. Pre-diagnostic warfarin use ranged from 2.4 to 4.7 %. There was little evidence of any strong association between warfarin use pre-diagnosis and cancer-specific mortality in prostate (adjusted HR 1.03, 95 % CI 0.84-1.26), lung (adjusted HR 1.06, 95 % CI 0.96-1.16), breast (adjusted HR 0.81, 95 % CI 0.62-1.07), or colorectal (adjusted HR 0.88, 95 % CI 0.77-1.01) cancer patients. Dose-response analyses did not reveal consistent evidence of reductions in users of warfarin defined by the number of prescriptions used and daily defined doses. CONCLUSIONS: There was little evidence of associations between pre-diagnostic use of warfarin and cancer-specific mortality in lung, prostate, breast, or colorectal cancer patients.


Assuntos
Neoplasias da Mama/mortalidade , Neoplasias Colorretais/mortalidade , Neoplasias Pulmonares/mortalidade , Neoplasias da Próstata/mortalidade , Varfarina/uso terapêutico , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Estudos de Coortes , Neoplasias Colorretais/tratamento farmacológico , Bases de Dados Factuais , Feminino , Humanos , Incidência , Neoplasias Pulmonares/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica/tratamento farmacológico , Modelos de Riscos Proporcionais , Neoplasias da Próstata/tratamento farmacológico
7.
Cancer Epidemiol ; 37(6): 897-904, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24042024

RESUMO

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) have many anticarcinogenic properties via the inhibition of cyclooxygenase 2 (COX-2). Only one study, a cohort study examining risk of all cancers, investigated their role in cervical cancer with inconsistent findings between non-aspirin NSAIDs and aspirin. The aim of this study was to further investigate NSAID/aspirin use and cervical cancer risk. METHODS: Using the United Kingdom Clinical Practice Research Datalink, 724 women diagnosed with cervical cancer between 1 January, 1995 and December 2010 were compared to 3479 women (without cervical cancer) matched on year of birth and general practice. Conditional logistic regression analysis adjusted for smoking, sexually transmitted infections, HRT and contraceptive use, was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for cervical cancer risk among users of any oral NSAIDs, non-aspirin NSAIDs and aspirin, as assessed from primary care prescribing data. RESULTS: Excluding the year prior to diagnosis, there was no association in adjusted analyses between ever vs. never use of an NSAID (OR 0.92, 95% CI 0.77-1.09), non-aspirin NSAID (OR 0.95, 95% CI 0.80-1.13) or low-dose aspirin (OR 1.07, 0.80-1.44) and cervical cancer risk. In analysis of daily defined doses, there was no association with cervical cancer risk comparing the highest users to non-users of NSAIDs (OR 0.98, 95% CI 0.69-1.39) or non-aspirin NSAIDs (OR 1.00, 95% CI 0.70-1.43) or low-dose aspirin (OR 1.04, 95% CI 0.59-1.81). CONCLUSION: This large historical cohort study found no evidence of an association between non-aspirin NSAID or aspirin use and cervical cancer risk.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Aspirina/uso terapêutico , Neoplasias do Colo do Útero/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Razão de Chances , Prognóstico , Fatores de Risco , Reino Unido , Neoplasias do Colo do Útero/cirurgia , Adulto Jovem
8.
Cancer Causes Control ; 24(11): 2027-34, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23990380

RESUMO

PURPOSE: The aetiology of primary brain tumours is largely unknown; the role of non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin use and glioma risk has been inconclusive, but few population-based studies with reliable prescribing data have been conducted, and the association with meningioma risk has yet to be assessed. METHODS: The UK Clinical Practice Research Datalink was used to assess the association between aspirin and non-aspirin NSAID use and primary brain tumour risk using a nested case-control study design. Conditional logistic regression analysis was performed on 5,052 brain tumour patients aged 16 years and over, diagnosed between 1987 and 2009 and 42,678 controls matched on year of birth, gender and general practice, adjusting for history of allergy and hormone replacement therapy use in the glioma and meningioma models, respectively. RESULTS: In conditional logistic regression analysis, excluding drug use in the year preceding the index date, there was no association with non-aspirin NSAID use (OR 0.96, 95 % CI 0.81-1.13) or glioma risk comparing the highest category of daily defined dose to non-users; however, non-aspirin NSAID use was positively associated with meningioma risk (OR 1.35, 95 % CI 1.06-1.71). No association was seen with high- or low-dose aspirin use irrespective of histology. CONCLUSIONS: This large nested case-control study finds no association between aspirin or non-aspirin NSAID use and risk of glioma but a slight increased risk with non-aspirin NSAIDs and meningioma.


Assuntos
Anti-Inflamatórios não Esteroides/efeitos adversos , Neoplasias Encefálicas/induzido quimicamente , Glioma/induzido quimicamente , Adulto , Idoso , Aspirina/efeitos adversos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Neoplasias Meníngeas/induzido quimicamente , Meningioma/induzido quimicamente , Pessoa de Meia-Idade , Razão de Chances , Medição de Risco/métodos , Medição de Risco/estatística & dados numéricos , Fatores de Risco
9.
Eur J Cancer ; 49(5): 1109-16, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23146960

RESUMO

AIM: Intrauterine, early life and maternal exposures may have important consequences for cancer development in later life. The aim of this study was to examine perinatal and birth characteristics with respect to Cutaneous malignant melanoma (CMM) risk. METHODS: The Northern Ireland Child Health System database was used to examine gestational age adjusted birth weight, infant feeding practices, parental age and socioeconomic factors at birth in relation to CMM risk amongst 447,663 infants delivered between January 1971 and December 1986. Follow-up of histologically verified CMM cases was undertaken from the beginning of 1993 to 31st December 2007. Multivariable adjusted unconditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) of CMM risk. RESULTS: A total of 276 CMM cases and 440,336 controls contributed to the final analysis. In reference to normal (gestational age-adjusted) weight babies, those heaviest at birth were twice as likely to develop CMM OR 2.4 (95% CI 1.1-5.1). Inverse associations with CMM risk were observed with younger (<25 years) parental age at birth and both a higher birth order and greater household density OR 0.61 (95% CI 0.37-0.99) and OR 0.56 (95% CI 0.30-1.0) respectively. CONCLUSION: This large study of early onset melanoma supports a positive association with higher birth weight (imperatively gestational age adjusted) and CMM risk which may be related to factors which drive intrauterine foetal growth. Strong inverse associations observed with higher birth order and household density suggest that early-life immune modulation may confer protection; findings which warrant further investigation in prospective analyses.


Assuntos
Exposição Ambiental/efeitos adversos , Melanoma/etiologia , Parto/fisiologia , Neoplasias Cutâneas/etiologia , Adulto , Fatores Etários , Peso ao Nascer/fisiologia , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Masculino , Melanoma/epidemiologia , Irlanda do Norte/epidemiologia , Fatores de Risco , Neoplasias Cutâneas/epidemiologia , Adulto Jovem
10.
Oral Oncol ; 48(12): 1191-201, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22841677

RESUMO

Human Papillomavirus (HPV) related oropharyngeal squamous cell carcinomas (OPSCCs) are reported to have improved prognosis and survival in comparison to other head and neck squamous cell cancers (HNSCCs). This systematic review and meta-analysis examines survival differences in HPV-positive HNSCC and OPSCC subtypes including tonsillar carcinoma in studies not previously investigated. Four electronic databases were searched from their inception till April 2011. A random effects meta-analysis was used to pool study estimates evaluating disease-specific (death from HNSCC), overall (all-cause mortality), progression-free and disease-free (recurrence free) survival outcomes in HPV-positive vs. HPV-negative HNSCCs. All statistical tests were two-sided. Forty-two studies were included. Patients with HPV-positive HNSCC had a 54% better overall survival compared to HPV-negative patients HR 0.46 (95% CI 0.37-0.57); the pooled HR for tonsillar cancer and OPSCC was 0.50 (95% CI 0.33-0.77) and HR 0.47 (95% CI 0.35-0.62) respectively. The pooled HR for disease specific survival was 0.28 (95% CI 0.19-0.40); similar effect sizes were found irrespective of the adjustment for confounders, HPV detection methods or study location. Both progression-free survival and disease-free survival were significantly improved in HPV-positive HNSCCs. HPV-positive HNSCCs and OPSCCs patients have a significantly lower disease specific mortality and are less likely to experience progression or recurrence of their cancer than HPV-negative patients; findings which have connotations for treatment selection in these patients.


Assuntos
Neoplasias de Cabeça e Pescoço/virologia , Papillomaviridae/patogenicidade , Humanos , Papillomaviridae/isolamento & purificação , Análise de Sobrevida
11.
J Music Ther ; 38(1): 66-73, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11407966

RESUMO

As music therapists continue to discover more about the therapeutic powers of music, it is interesting now and then to look to the past in order to seek the roots of our contemporary practices. In this regard, the writings of eighteenth-century physicians are pivotal in the development of music therapy, for it was these individuals who first began to depend greatly upon scientific experimentation and observation to formulate their procedures. Representative of this stage in the history of music therapy are the findings of the renowned London physician Richard Brocklesby, the only doctor to write a treatise on music therapy in eighteenth-century England. The subjects treated by Brocklesby in his Reflections on the Power of Music (1749) include his musical remedies for the excesses of various emotions-particularly fear, excessive joy, and excessive sadness. He also discusses his musical remedies for diseases of the mind recognized in the eighteenth century-delirium, frenzy, melancholia, and maniacal cases. He considers music as well an aid to the elderly and to pregnant women. In short, Brocklesby provides a lively account of the curative powers of music as viewed in the mid-eighteenth century by an excellent medical mind.


Assuntos
Musicoterapia/história , Afeto , Inglaterra , História do Século XVIII
12.
Cutis ; 53(1): 44-8, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8119078

RESUMO

Although ultrasound has been used for many years for a variety of medical diagnostic purposes, only recently have systems been designed that allow for its application to skin. High-resolution ultrasound systems now permit accurate, quantitative, noninvasive assessment of skin and cutaneous diseases. This technique will assist in the management of both inflammatory and neoplastic processes. Scans of skin obtained with a prototype high-resolution ultrasound system are presented. The computer-assisted creation of three-dimensional images from sequential B-mode scans is described.


Assuntos
Dermatopatias/diagnóstico por imagem , Humanos , Pele/diagnóstico por imagem , Ultrassonografia/métodos
13.
J Ultrasound Med ; 12(10): 601-8, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8246339

RESUMO

The ability of ultrasonic tissue characterization to differentiate and classify benign and malignant breast tissues in vivo in patients with palpable breast masses and in vitro in excised breast tissue was evaluated. One-hundred and twenty-four in vivo and 89 in vitro studies were performed using a technique of UTC based on parameters from the power spectrum of backscattered echoes. Sensitivities and specificities for diagnosing carcinoma were 86 and 84% for in vivo studies and 94 and 92% for in vitro studies. These UTC parameters provided threshold values for color-coding breast lesion images. The results of this preliminary investigation suggest that UTC provides a basis for assessing more accurately lesions suspected of being malignant prior to biopsy and possibly for evaluating breast lesions noninvasively.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Reações Falso-Positivas , Feminino , Doença da Mama Fibrocística/diagnóstico por imagem , Humanos , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Ultrassonografia Mamária
14.
J Am Acad Dermatol ; 29(2 Pt 1): 171-5, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8335733

RESUMO

BACKGROUND: Visual examination and cutaneous biopsies, two major tools in dermatologic diagnosis, do not provide structural information regarding the entire tissue volume. OBJECTIVE: Our purpose was to develop a high-resolution ultrasound system that quickly, with minimal operator interaction, displays structural data on the entire tissue volume. METHODS: A prototype ultrasound B-scan system was developed and operated at nominal center frequencies between 35 and 50 MHz, with computer processing of data to produce three-dimensional images. These images displayed as three-dimensional "blocks" can be sectioned to provide multiple images of internal structure (i.e., "acoustic biopsies"). RESULTS: B-scans and associated three-dimensional images were obtained from assorted skin sites in selected patients. CONCLUSION: This technique provides a valuable diagnostic tool that is now being further evaluated.


Assuntos
Processamento de Imagem Assistida por Computador , Dermatopatias/diagnóstico por imagem , Adulto , Carcinoma Basocelular/diagnóstico por imagem , Feminino , Humanos , Microcomputadores , Pessoa de Meia-Idade , Valores de Referência , Pele/diagnóstico por imagem , Neoplasias Cutâneas/diagnóstico por imagem , Software , Ultrassonografia
16.
J Vasc Surg ; 17(3): 470-8, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8445741

RESUMO

PURPOSE: The ability of ultrasonic tissue characterization based on radiofrequency signal processing to detect compositional differences in thrombi of varying ages was evaluated in vivo. METHODS: Thrombi were produced in 49 jugular veins of 26 anesthetized 18 to 20 kg pigs by partial ligation and application of direct electric current. Thrombi were imaged 30 minutes after formation and 1, 7, and 14 days later with a color Doppler ultrasound scanner that identified the thrombi, and acquired radio frequency data for ultrasonic tissue characterization analysis. Ultrasonic tissue characterization used two parameters from the normalized power spectrum, slope, and intercept, which are related to scatterer size, scatterer concentration, and acoustic-impedance differences between scatterers and surrounding medium. Previous in vitro studies demonstrated that lower slope and higher intercept values correlated with greater cellularity and more-dense fibrin mesh. Histologic examination was performed for each time period. The values of slope and intercept for each timed observation were compared by a multilinear discriminant analysis. RESULTS: There were no statistical differences between day 0 and day 1. Statistically-significant differences in ultrasonic tissue characterization parameters were seen between all other time intervals with p values < 0.01. Older thrombi tended to demonstrate higher slope and lower intercept values. These ultrasonic tissue characterization changes correlated with a red cell and fibrin-mesh density reduction, which was confirmed by histologic findings and was indicative of partial spontaneous thrombolysis. The degree of spontaneous thrombolysis provides an estimate of the age of thrombi. CONCLUSION: Ultrasonic tissue characterization is capable of distinguishing age differences in thrombi in an animal model and has the potential for noninvasive application in clinical diagnosis.


Assuntos
Tromboflebite/diagnóstico por imagem , Animais , Modelos Animais de Doenças , Veias Jugulares/diagnóstico por imagem , Modelos Lineares , Análise Multivariada , Suínos , Fatores de Tempo , Ultrassonografia
17.
Ultrasound Med Biol ; 19(1): 39-43, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8456527

RESUMO

The purpose of this study was to determine the effect of blood flow perfusion and red cell content on ultrasonic scattering by liver tissue. Data acquisition for ultrasonic tissue characterization (UTC) employing analysis of the backscattered echoes from the power spectrum was obtained from the same region of pig liver tissue under four conditions: 1) normal perfusion in situ, 2) ischemia in situ in the living pig, 3) ischemia in situ immediately postmortem, and 4) immediately after excision of the liver. Discriminant function analysis was used to evaluate differences in the two basic parameters from the normalized power spectrum: slope and intercept. Normal perfused liver had significantly higher intercept values and lower slope values than liver under the other three conditions. Excised liver showed the lowest intercept and highest slope values (p < 0.01). These experiments indicate that differences in perfusion produce significant differences in ultrasonic scattering by liver tissue (ischemia caused a 3 dB drop in intercept amplitude). Normal or ischemic in vivo and in vitro liver tissue is associated with different patterns of ultrasonic scattering, and scattering data under these various circumstances are not equivalent.


Assuntos
Fígado/diagnóstico por imagem , Fígado/fisiopatologia , Animais , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Isquemia/diagnóstico por imagem , Isquemia/fisiopatologia , Fígado/irrigação sanguínea , Masculino , Perfusão , Suínos , Ultrassonografia
18.
Ultrasound Med Biol ; 19(4): 299-308, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8346604

RESUMO

Ultrasonic tissue characterization (UTC) employing slope and Y-intercept parameters from the normalized power spectrum of backscattered echoes was employed in vivo to study compositional changes in the walls of pig jugular veins in which thrombi were experimentally induced. Light microscopy revealed these changes to be intimal hyperplasia with an early predominance of smooth muscle cells and a later mixture of smooth muscle cells and collagen deposits. UTC distinguished intimal hyperplasia from previously reported data from luminal thrombosis UTC. Furthermore, UTC was able to discriminate between early (predominantly smooth muscle cells) and older (smooth muscle cells plus collagen deposits) intimal hyperplasia. The study suggests that intimal hyperplasia in the experimental model used may be organized thrombus and that UTC may be able to follow both the development of wall changes as well as luminal changes occurring in venous thrombosis.


Assuntos
Veias Jugulares/diagnóstico por imagem , Veias Jugulares/patologia , Túnica Íntima/diagnóstico por imagem , Túnica Íntima/patologia , Animais , Colágeno , Modelos Animais de Doenças , Hiperplasia , Suínos , Tromboflebite/diagnóstico por imagem , Tromboflebite/patologia , Ultrassonografia
19.
Artigo em Inglês | MEDLINE | ID: mdl-18263139

RESUMO

Data obtained from a scanning laser acoustic microscope (SLAM) were used to examine several aspects of ultrasonic backscattering from the liver. Phase interferograms from normal and abnormal human-liver specimens were digitized, and a series of algorithms was used to compute images of propagation velocity within the specimens. The propagation velocity images were then employed to simulate A- and B-mode results. These initial simulations were used to investigate how ultrasonic echo signals are related to tissue microstructure. Among the topics examined were B-mode speckling, frequency and beamwidth effects, and angulation dependencies.

20.
Ultrasound Med Biol ; 18(4): 399-410, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1509615

RESUMO

This in vitro study was designed to evaluate the ability of ultrasonic tissue characterization (UTC) based on power spectrum analysis of backscattered radio-frequency echo signals to distinguish two prominent variables of thrombi: cellularity (primarily red cell content) and fibrin-mesh density. Six types of clots simulating thrombus components were prepared by varying red-cell and platelet concentrations and shear forces during clotting. Data were acquired with a linear-array transducer, digitized, and analyzed in terms of slope and intercept parameters obtained from normalized power spectra of radio-frequency echo signals. Increased cellularity and fibrin-mesh density both produced lower slope and higher intercept values, which permitted statistically significant discrimination of cellularity and mesh density in the six types of clots analyzed. Shearing forces and (to a lesser degree) platelet concentrations increased fibrin-mesh density. This study suggests that UTC based upon the power spectrum of echo signals may be used to detect and follow compositional differences that have clinical relevance in the diagnosis and follow-up of thrombi.


Assuntos
Coagulação Sanguínea , Eritrócitos/diagnóstico por imagem , Fibrina/fisiologia , Trombose/diagnóstico por imagem , Plaquetas/diagnóstico por imagem , Humanos , Agregação Plaquetária/fisiologia , Ultrassonografia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...