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1.
Eur J Dev Res ; 34(6): 2787-2809, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34754146

RESUMO

By combining household survey data before and during the COVID-19 pandemic with detailed tax-benefit simulations, this paper quantifies the distributional effects of COVID-19 in Ecuador and the role of tax-benefit policies in mitigating the immediate impact of the economic shocks. Our results show a dramatic increase in income poverty and inequality between December 2019 and June 2020, the period when the economy was hit the hardest. The national poverty headcount increases from 25.7 to 58.2%, the extreme poverty headcount from 9.2 to 38.6%, and the Gini coefficient from 0.461 to 0.592. On average, household disposable income drops by 41%. The new Family Protection Grant provides income protection for the poorest income decile. However, overall tax-benefit policies do little to mitigate the losses in household incomes due to the pandemic. Informal workers, in particular, are left unprotected due to the lack of income support in the event of unemployment. Supplementary Information: The online version contains supplementary material available at 10.1057/s41287-021-00490-1.


En combinant les données d'enquêtes auprès des ménages avant et pendant la pandémie de COVID-19 avec des simulations détaillées d'impôts et de prestations, cet article quantifie les effets distributifs de la COVID-19 en Équateur et le rôle que jouent les politiques d'impôts et des prestations pour atténuer l'impact immédiat des chocs économiques. Nos résultats montrent une hausse spectaculaire de la pauvreté monétaire et des inégalités entre décembre 2019 et juin 2020, période durant laquelle l'économie a été le plus durement touchée. Le taux national de pauvreté passe de 25,7% à 58,2%, le taux d'extrême pauvreté de 9,2% à 38,6% et le coefficient de Gini de 0,461 à 0,592. En moyenne, le revenu disponible des ménages baisse de 41%. La nouvelle allocation de protection familiale offre une assurance de protection des revenus aux 10% des ménages les plus pauvres. Cependant, de façon générale, les politiques d'impôts et des prestations en font peu pour atténuer les pertes de revenus des ménages en raison de la pandémie. Les travailleurs et travailleuses informel·le·s, en particulier, sont laissé·e·s sans protection en raison de l'absence d'allocation de revenu en cas de chômage.

2.
BMC Med ; 19(1): 310, 2021 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-34844596

RESUMO

BACKGROUND: We developed an integrated model called Microsimulation for Income and Child Health (MICH) that provides a tool for analysing the prospective effects of fiscal policies on childhood health in European countries. The aim of this first MICH study is to evaluate the impact of alternative fiscal policies on childhood overweight and obesity in Italy. METHODS: MICH model is composed of three integrated modules. Firstly, module 1 (M1) simulates the effects of fiscal policies on disposable household income using the tax-benefit microsimulation program EUROMOD fed with the Italian EU-SILC 2010 data. Secondly, module 2 (M2) exploits data provided by the Italian birth cohort called Nascita e Infanzia: gli Effetti dell'Ambiente (NINFEA), translated as Birth and Childhood: the Effects of the Environment study, and runs a series of concatenated regressions in order to estimate the prospective effects of income on child body mass index (BMI) at different ages. Finally, module 3 (M3) uses dynamic microsimulation techniques that combine the population structure and incomes obtained by M1, with regression model specifications and estimated effect sizes provided by M2, projecting BMI distributions according to the simulated policy scenarios. RESULTS: Both universal benefits, such as universal basic income (BI), and targeted interventions, such as child benefit (CB) for poorer households, have a significant effect on childhood overweight, with a prevalence ratio (PR) in 10-year-old children-in comparison with the baseline fiscal system-of 0.88 (95%CI 0.82-0.93) and 0.89 (95%CI 0.83-0.94), respectively. The impact of the fiscal reforms was even larger for child obesity, reaching a PR of 0.67 (95%CI 0·50-0.83) for the simulated BI and 0.64 (95%CI 0.44-0.84) for CB at the same age. While both types of policies show similar effects, the estimated costs for a 1% prevalence reduction in overweight and obesity with respect to the baseline scenario is much lower with a more focalised benefit policy than with universal ones. CONCLUSIONS: Our results show that fiscal policies can have a strong impact on childhood health conditions. Focalised interventions that increase family income, especially in the most vulnerable populations, can help to prevent child overweight and obesity. Robust microsimulation models to forecast the effects of fiscal policies on health should be considered as one of the instruments to reach the Health in All Policies (HiAP) goals.


Assuntos
Política Fiscal , Obesidade Infantil , Coorte de Nascimento , Índice de Massa Corporal , Criança , Saúde da Criança , Europa (Continente) , Política de Saúde , Humanos , Sobrepeso , Obesidade Infantil/epidemiologia , Obesidade Infantil/prevenção & controle , Prevalência
3.
Rev. chil. enferm. respir ; 36(4)dic. 2020.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1388125

RESUMO

Resumen La Fibrosis Quística (FQ) es la enfermedad hereditaria de pronóstico reservado más frecuente en raza blanca. Desde el año 2003, Chile inicia un Programa Nacional de Fibrosis Quística, de carácter integral, dirigido por la Unidad de Salud Respiratoria del Ministerio de Salud. Hasta la fecha, los principales resultados del Programa registran una significativa mayor sobrevida (promedio 27 años) y una significativa reducción en la edad de diagnóstico de los pacientes ingresados desde 2006 en adelante. El acceso a la canasta GES (Garantías Explícitas en Salud), la implementación del tamizaje neonatal en algunas regiones del país, la organización y la constitución de equipos entrenados en FQ de diversas especialidades, ha contribuido a mejorar los resultados. Si bien las principales manifestaciones son del aparato respiratorio y digestivo, el carácter multisistémico de la FQ obliga a conocer los distintos aspectos involucrados en su manejo, a fin de optimizar los resultados del tratamiento y los recursos invertidos, tanto en el sector público como privado. Este documento es una revisión y actualización sobre los principales aspectos del diagnóstico, seguimiento y tratamiento de las manifestaciones respiratorias y no respiratorias de la FQ.


Cystic Fibrosis (CF) is the most frequent hereditary disease in whites, with a reserved prognosis. Since 2003, Chile began a comprehensive National Cystic Fibrosis Program, directed by the Respiratory Health Unit of the Ministry of Health. To date, the main results of the Program record a significantly longer survival (average 27 years) and a significant reduction in the age of diagnosis of patients admitted from 2006 onwards. Access to Chilean Explicit Health Guarantees, the implementation of neonatal screening in some regions of the country, the organization and setting up of CF-trained teams of various specialties, has contributed to improving results. Although the main manifestations are of the respiratory and digestive system, the multisystemic nature of CF makes it necessary to know the different aspects involved in its management, in order to optimize the results of the treatment and the resources invested, both in the public and private sectors. This document is a review and an update on the main aspects of the diagnosis, monitoring and treatment of the respiratory and non-respiratory manifestations of CF.

4.
Neumol. pediátr. (En línea) ; 15(4): 429-483, 2020. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1146394

RESUMO

Cystic Fibrosis (CF) is the most frequent hereditary disease in whites, with a reserved prognosis. Since 2003, Chile began a comprehensive National Cystic Fibrosis Program, directed by the Respiratory Health Unit of the Ministry of Health. To date, the main results of the Program record a significantly longer survival (average 27 years) and a significant reduction in the age of diagnosis of patients admitted from 2006 onwards. Access to Chilean Explicit Health Guarantees, the implementation of neonatal screening in some regions of the country, the organization and setting up of CF-trained teams of various specialties, has contributed to improving results. Although the main manifestations are of the respiratory and digestive system, the multisystemic nature of CF makes it necessary to know the different aspects involved in its management, in order to optimize the results of the treatment and the resources invested, both in the public and private sectors. This document is a review and an update on the main aspects of the diagnosis, monitoring and treatment of the respiratory and non-respiratory manifestations of CF.


La Fibrosis Quística (FQ) es la enfermedad hereditaria de pronóstico reservado más frecuente en raza blanca. Desde el año 2003, Chile inicia un Programa Nacional de Fibrosis Quística, de carácter integral, dirigido por la Unidad de Salud Respiratoria del Ministerio de Salud. Hasta la fecha, los principales resultados del Programa registran una significativa mayor sobrevida (promedio 27 años) y una significativa reducción en la edad de diagnóstico de los pacientes ingresados desde 2006 en adelante. El acceso a la canasta GES (Garantías Explícitas en Salud), la implementación del tamizaje neonatal en algunas regiones del país, la organización y la constitución de equipos entrenados en FQ de diversas especialidades, ha contribuido a mejorar los resultados. Si bien las principales manifestaciones son del aparato respiratorio y digestivo, el carácter multisistémico de la FQ obliga a conocer los distintos aspectos involucrados en su manejo, a fin de optimizar los resultados del tratamiento y los recursos invertidos, tanto en el sector público como privado. Este documento es una revisión y actualización sobre los principales aspectos del diagnóstico, seguimiento y tratamiento de las manifestaciones respiratorias y no respiratorias de la FQ.


Assuntos
Humanos , Criança , Adulto , Prestação Integrada de Cuidados de Saúde , Fibrose Cística/diagnóstico , Fibrose Cística/terapia , Chile , Estado Nutricional , Fibrose Cística/reabilitação , Consenso , Recursos em Saúde
5.
Andrology ; 5(5): 889-897, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28704587

RESUMO

Animal data shows that testosterone administration increases the volume of some parenchymal organs. However, the effects of exogenous testosterone on solid abdominal organs in humans remain unknown. The present study evaluated the effects of testosterone administration on the volume of liver, spleen and kidneys in a dose-response trial. Young healthy men aged 18-50 years participating in the 5α-Reductase (5aR) Trial. All participants received monthly injections of 7.5 mg leuprolide acetate to suppress endogenous testosterone secretion and weekly injections of 50, 125, 300 or 600 mg of testosterone enanthate, and were randomized to receive either 2.5 mg dutasteride (5 α-reductase inhibitor) or placebo daily for 20 weeks. Liver, spleen and kidney volumes were measured at baseline and the end of treatment using 1.5-Tesla magnetic resonance imaging. The dose-effect of testosterone on changes in the volume of parenchymal organs was evaluated by linear regression model. The association between changes in total testosterone (TT) levels and changes in organ volumes were assessed. Testosterone administration increased liver volume dose-dependently (17.4 cm3 per 100 mg of weekly testosterone enanthate; p = 0.031); the increase in liver volume was positively associated with changes in TT levels (R2  = 0.08, p = 0.024). A dose-dependent, but non-significant, increase in kidney volumes was also seen. Inclusion of dutasteride use into the models showed an independent association of randomization to dutasteride group with liver volume increase. In conclusion, Testosterone administration increased the liver volume in a dose-dependent manner. The potential changes in parenchymal organs should be considered when interpreting apparent changes in lean mass in response to anabolic interventions.


Assuntos
3-Oxo-5-alfa-Esteroide 4-Desidrogenase/farmacologia , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Baço/efeitos dos fármacos , Testosterona/análogos & derivados , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/administração & dosagem , Adulto , Composição Corporal , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão/efeitos dos fármacos , Testosterona/administração & dosagem , Testosterona/farmacologia , Adulto Jovem
6.
Dentomaxillofac Radiol ; 44(7): 20150047, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25974063

RESUMO

OBJECTIVES: To investigate the location-specific tissue properties and age-related changes of the facial fat and facial muscles using quantitative MRI (qMRI) analysis of longitudinal magnetization (T1) and transverse magnetization (T2) values. METHODS: 38 subjects (20 males and 18 females, 0.5-87 years old) were imaged with a mixed turbo-spin echo sequence at 1.5 T. T1 and T2 measurements were obtained within regions of interest in six facial fat regions including the buccal fat and subcutaneous cheek fat, four eyelid fat regions (lateral upper, medial upper, lateral lower and medial lower) and five facial muscles including the orbicularis oculi, orbicularis oris, buccinator, zygomaticus major and masseter muscles bilaterally. RESULTS: Within the zygomaticus major muscle, age-associated T1 decreases in females and T1 increases in males were observed in later life with an increase in T2 values with age. The orbicularis oculi muscles showed lower T1 and higher T2 values compared to the masseter, orbicularis oris and buccinator muscles, which demonstrated small age-related changes. The dramatic age-related changes were also observed in the eyelid fat regions, particularly within the lower eyelid fat; negative correlations with age in T1 values (p<0.0001 for age) and prominent positive correlation in T2 values in male subjects (p<0.0001 for male×age). Age-related changes were not observed in T2 values within the subcutaneous cheek fat. CONCLUSIONS: This study demonstrates proof of concept using T1 and T2 values to assess age-related changes of the facial soft tissues, demonstrating tissue-specific qMRI measurements and non-uniform ageing patterns within different regions of facial soft tissues.


Assuntos
Envelhecimento/fisiologia , Face/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Tecido Adiposo/anatomia & histologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bochecha/anatomia & histologia , Criança , Pré-Escolar , Pálpebras/anatomia & histologia , Músculos Faciais/anatomia & histologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tela Subcutânea/anatomia & histologia
7.
AJNR Am J Neuroradiol ; 34(3): 622-7, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22878006

RESUMO

BACKGROUND AND PURPOSE: Assessment of bone marrow is most commonly performed qualitatively in the spine or other large long bones. The craniofacial bones are less ideal for bone marrow analysis because of the relatively small bone marrow volume. Because patients with SCD often undergo repeated brain imaging to evaluate for cerebral vaso-occlusive disease, quantitative assessment of craniofacial bone marrow is a reasonable possibility in these patients. The purpose of this study was to investigate specific sickle cell disease changes in craniofacial bone marrow quantitatively by analyzing T1, T2, and secular-T2 relaxation times and volume with the use of quantitative MRI. MATERIALS AND METHODS: Fourteen patients with SCD and 17 control subjects were imaged with the mixed TSE pulse sequence at 1.5T. The craniofacial bones were manually segmented by using 3D Slicer to generate bone marrow volumes and to provide T1, T2, and secular-T2 relaxation times. RESULTS: All subjects exhibited a bimodal T1 histogram. In the SCD group, there was a decrease in amplitude in the first T1 peak and an increase in amplitude in the second T1 peak. The first T1 peak showed a significant increase in relaxation time compared with control subjects (P < .0001), whereas there was no significant difference in the second T1 peak. T2 and secular-T2 relaxation times were significantly shorter in the SCD group (T2, P < .0001; secular-T2, P < .0001). Increasing numbers of blood transfusions resulted in a decrease in T2 and secular-T2 times. Patients with SCD exhibited a larger bone marrow volume compared with control subjects, even after standardization. CONCLUSIONS: Patients with SCD exhibited significant quantifiable changes in the craniofacial bone marrow because of failure of red-to-yellow marrow conversion and iron deposition that can be identified by qMRI relaxometry and volumetry. Both qMRI relaxometry and volumetry may be used as noninvasive tools for assessment of disease severity.


Assuntos
Algoritmos , Anemia Falciforme/patologia , Medula Óssea/patologia , Ossos Faciais/patologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
8.
Dentomaxillofac Radiol ; 41(8): 630-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23166360

RESUMO

OBJECTIVES: The purpose of this prospective study was to characterize the MR relaxometric features of the major salivary glands in patients with sickle cell disease (SCD). METHODS: 15 patients with SCD (aged 19.8-43.6 years) and 12 controls were imaged with the mixed turbo-spin echo pulse sequence. The major salivary glands were manually segmented and T1, T2 and secular T2 relaxometry histograms were modelled with Gaussian functions. RESULTS: Shortened T1 relaxation times were seen solely in the submandibular glands of patients with SCD (747.5±54.8 ms vs 807.1±38.3 ms, p<0.001). Slight T2 and secular T2 shortening were seen in the parotid gland; however, this difference was not significant (p=0.07). The sublingual gland showed no changes under MR relaxometry. There was no difference in glandular volumes, and no correlation was demonstrated between history of blood transfusion and salivary gland relaxometry. CONCLUSIONS: Patients with SCD exhibited changes in quantitative MRI T1 relaxometry histograms of the submandibular glands.


Assuntos
Anemia Falciforme/patologia , Imageamento por Ressonância Magnética/métodos , Glândulas Salivares/patologia , Adulto , Anemia Falciforme/terapia , Estudos de Casos e Controles , Transfusão de Eritrócitos/estatística & dados numéricos , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/instrumentação , Masculino , Tamanho do Órgão , Glândula Parótida/patologia , Estudos Prospectivos , Estudos Retrospectivos , Glândula Sublingual/patologia , Glândula Submandibular/patologia , Adulto Jovem
9.
Osteoarthritis Cartilage ; 18(8): 1062-6, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20472082

RESUMO

OBJECTIVE: Aim was to compare volumetric and semi-quantitative (SQ) measurements of subchondral bone marrow lesions (BMLs) on non-fat-suppressed (FS) T1-weighted (w), T1-w FS contrast enhanced (CE) and proton density (PD)-w FS images in order to define which sequence depicts the lesions to their maximum extent and if T1-w FS CE images and PD-w FS images may be used interchangeably to assess BMLs in a volumetric or SQ fashion. DESIGN: Thirty-two patients with clinical knee osteoarthritis (OA) were scanned on a standard 1.5 T MRI system. A total of 47 BMLs were identified and were manually segmented on all three sequences. BMLs were also assessed semiquantitatively using the Whole Organ Magnetic Resonance Imaging Score (WORMS). The volumetric and SQ results were compared across the three imaging sequences using paired t-tests. RESULTS: Eighty-three percent of the lesions appeared largest on the PD-w FS sequence. Significant differences were observed for volumetric measurements between all three sequences (P < 0.001), however the mean volume difference between PD-w FS and T1-w FS CE (38%) was much smaller than for non-FS T1-w and PD-w FS/T1-w FS CE sequences (195% and 114%, respectively). Significant differences in WORMS scores were noted between PD-w FS and non-FS T1-w images and between T1-w FS CE and non-FS T1-w images (P < 0.001), but no significant difference was observed between PD-w FS and T1-w FS CE images. CONCLUSION: Our findings suggest that the T1-w FS CE and PD-w FS sequences may be interchangeably used for quantitative volumetric and SQ assessment of BMLs.


Assuntos
Doenças da Medula Óssea/patologia , Imageamento por Ressonância Magnética/métodos , Osteoartrite do Joelho/patologia , Idoso , Medula Óssea , Humanos , Articulação do Joelho , Masculino , Pessoa de Meia-Idade , Estatística como Assunto
10.
Rev. argent. anestesiol ; 61(1): 3-6, ene.-feb. 2003.
Artigo em Espanhol | BINACIS | ID: bin-6023

RESUMO

La hidatidosis es una infección causada por el echinococus granulosus, de carácter endémico, presente especialmente en la Mesopotamia y Patagonia argentina. Su tratamiento es el quirúrgico, en cualquier localización. Nosotros describimos un caso clínico de localización renal, tratado por drenaje percutáneo, bajo anestesia regional continua. Señalamos las potenciales complicaciones amenazantes de la vida, tales como el shock anafiláctico y el síndrome hiperosmolar por hipernatremia, que pueden presentarse y para las cuales el anestesiólogo debe estar advertido, para su detección y manejo perioperatorio. (AU)


Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Equinococose/etiologia , Equinococose/complicações , Equinococose/epidemiologia , Equinococose/cirurgia , Equinococose/terapia , Nefropatias , Doenças Renais Císticas/cirurgia , Anestesia Epidural/métodos , Anestesia Epidural/efeitos adversos , Drenagem/métodos , Fatores de Risco , Anafilaxia/complicações , Hipernatremia/complicações , Cuidados Intraoperatórios
11.
Rev. argent. anestesiol ; 61(1): 3-6, ene.-feb. 2003.
Artigo em Espanhol | LILACS | ID: lil-341215

RESUMO

La hidatidosis es una infección causada por el echinococus granulosus, de carácter endémico, presente especialmente en la Mesopotamia y Patagonia argentina. Su tratamiento es el quirúrgico, en cualquier localización. Nosotros describimos un caso clínico de localización renal, tratado por drenaje percutáneo, bajo anestesia regional continua. Señalamos las potenciales complicaciones amenazantes de la vida, tales como el shock anafiláctico y el síndrome hiperosmolar por hipernatremia, que pueden presentarse y para las cuales el anestesiólogo debe estar advertido, para su detección y manejo perioperatorio.


Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Anestesia Epidural , Drenagem , Equinococose , Nefropatias , Doenças Renais Císticas , Anafilaxia , Hipernatremia , Cuidados Intraoperatórios , Fatores de Risco
12.
Scand J Rheumatol ; 29(1): 65-7, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10722261

RESUMO

We describe a 36-year-old woman with Primary Sjögren's Syndrome (PSS). Purpura, corneal perforation, metabolic acidosis, decreased glomerular filtration, hypokalemia, hyposthenuria, and polyuria were present. Chronic renal insufficiency and renal tubular acidosis type I were diagnosed. Kidney biopsy revealed mesangial glomerulonephritis, interstitial nephritis, and tubular atrophy. Replacement treatment with saliva, tears, and potassium citrate was started. She was given prednisone and cyclophosphamide. This would be the first description of PSS, mesangial glomerulonephritis, and chronic renal insufficiency.


Assuntos
Falência Renal Crônica/complicações , Nefrite Intersticial/complicações , Síndrome de Sjogren/complicações , Acidose Tubular Renal/complicações , Acidose Tubular Renal/patologia , Adulto , Feminino , Mesângio Glomerular/patologia , Humanos , Falência Renal Crônica/patologia , Nefrite Intersticial/patologia , Síndrome de Sjogren/patologia
13.
Semin Ultrasound CT MR ; 20(5): 281-93, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10527134

RESUMO

The tissue contrast principles and the technical aspects involved in the design of the imaging protocols currently used for clinical MR cholangiopancreatography are reviewed using a neutral terminology that is applicable to most of the high-field MRI equipment available from the major manufacturers. Furthermore, the technical discussions that follow are accompanied by a comprehensive set of tables listing the pulse sequence parameters used by the authors of the other articles in this issue. The tables are organized according to groups of parameters that determine the fundamental features of the protocols and of the generated images, specifically motion artifact reduction technique, scan geometry, image contrast, and recommended image post processing algorithm.


Assuntos
Sistema Biliar/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Pâncreas/anatomia & histologia , Algoritmos , Artefatos , Humanos , Processamento de Imagem Assistida por Computador
14.
Magn Reson Imaging Clin N Am ; 7(2): 289-301, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10382162

RESUMO

The mechanisms involved in the generation of motion artifacts in MR imaging are complex and depend both on the type and direction of motion as well as on the parameters of the imaging sequence chosen. The methods used to control or reduce motion artifacts are multiple and the appropriate method for use with any given clinical situation will depend on the particular hardware and software of the MR imaging unit, the patient's clinical status, and the specific organ or disease state to be imaged. Some general guidelines for clinical use that are applicable in most scenarios can be defined, although preferences for the different techniques vary. Appropriate T1-weighted images of the upper abdomen and liver can be obtained with breath-hold T1-weighted gradient echo. These images should be acquired with inferior-superior spatial presaturation pulses to reduce vascular pulsation artifact and ghosting. The application of GMN will depend on the individual MR imaging system. If sufficient coverage cannot be obtained with gradient-echo imaging, then conventional T1-weighted images with phase-encoding reordering is suggested. The addition of spatial presaturation pulses (inferior-superior) may be valuable. The use of fat suppression will further improve image quality by reducing ghost artifact and improving CNR, although SNR will decrease. T2-weighted imaging of the upper abdomen will depend greatly on the hardware and software of the MR imaging unit. Recent techniques of breath-hold T2-weighted imaging require faster and stronger gradients, and may not be universally available. If available, these techniques provide excellent anatomic detail, although image contrast (e.g., liver to spleen) may decrease. Respiratory-triggered FSE techniques are the preferred method of imaging in most centers, because the imaging time is considerably less than conventional T2-weighted imaging whereas the image quality is improved. Liver lesion detection capability of the various techniques is still under study. The addition of fat suppression appears to improve image quality further with an increase in lesion detection. By understanding the principles underlying motion artifacts, one can choose the appropriate method of artifact control tailored for the individual clinical situation. In addition, the recognition of the variable appearances of motion artifacts will prevent interpretive errors and misdiagnoses. Careful attention to motion artifact reduction techniques can greatly improve patient care.


Assuntos
Imageamento por Ressonância Magnética/métodos , Artefatos , Humanos , Imageamento por Ressonância Magnética/instrumentação , Movimento (Física)
15.
Magn Reson Imaging Clin N Am ; 7(2): 303-17, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10382163

RESUMO

As there are limitations in WB-MR angiography, so there are limitations in BB-MR angiography. Vessel morphology is visualized by means of the innermost nonattenuated layer of tissue, which, under ideal conditions, coincides with the luminal surface of the vessel wall. Vessel morphology may be depicted inaccurately whenever a portion of the vessel wall is undetectable with the MR imaging technique used. In such cases, vessel segments with exaggerated lumen diameter may result at locations where tissues with either a very short T2 or a low proton density are present. Another phenomenon that could potentially degrade the accuracy of vessel depiction with BB techniques is the effect of slowly flowing blood near the vessel walls. Residual blood signal would result in apparent vessel narrowing. Preliminary clinical experience in the brain, however, suggests that this adverse effect is less prominent with a turbo-SE-based BB technique than with a TOF WB technique. BB-MR angiography data sets may also present image postprocessing difficulties arising from the isointensity between the vessels and other dark structures such as bones and air-filled cavities. A limitation that is more specific to hybrid-SE-based BB-MR pulse sequences, particularly for very high spatial resolution applications, stems from the comparatively high RF specific absorption rates that result from the intensive use of 180 degrees refocusing pulses. GRASE-based BB-MR techniques that generate a fraction of the RF energy constitute a promising alternative for very high spatial resolution applications. In summary, to be effective, a BB technique must produce strong signal attenuation from flowing spins, ideally to the level of the baseline noise. Simultaneously it should produce good depiction of tissues with the comparatively short T2s characteristic of vessel walls and muscle, hence the need to operate with the shortest possible TE. Finally, high spatial resolution combined with fast data acquisition are requisites for imaging small vessels in the presence of motion, such as the carotid arteries. The flow properties of BB-MR angiographic sequences that meet these criteria were reviewed for different anatomic locations.


Assuntos
Angiografia por Ressonância Magnética/métodos , Humanos
17.
Magn Reson Med ; 41(3): 575-90, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10204883

RESUMO

The conditions in which the image intensity of vessels transporting laminar flow is attenuated in black-blood MR angiography (BB-MRA) with turbo spin-echo (TSE) and conventional spin-echo (CSE) pulse sequences are investigated experimentally with a flow phantom, studied theoretically by means of a Bloch equation-voxel sensitivity function (VSF) formalism, and computer modeled. The experiments studied the effects of: a) flow velocity, b) imaging axes orientation relative to the flow direction, and c) phase encoding order of the TSE train. The formulated Bloch equation-VSF theory describes flow effects in two-dimensional (2D)- and 3D-Fourier transform magnetic resonance imaging. In this theoretical framework, the main attenuation mechanism instrumental to BB-MRA, i.e., transverse magnetization dephasing caused by flow in the presence of the imaging gradients, is described in terms of flow-induced distortions of the individual voxel sensitivity functions. The computer simulations predict that the intraluminal homogeneity and extent of flow-induced image intensity attenuation increase as a function of decreasing vessel diameter, in support of the superior image quality achieved with TSE-based BB-MRA in the brain.


Assuntos
Circulação Cerebrovascular/fisiologia , Simulação por Computador , Processamento de Imagem Assistida por Computador/métodos , Angiografia por Ressonância Magnética/métodos , Modelos Cardiovasculares , Imagens de Fantasmas , Artéria Poplítea/fisiologia , Veia Poplítea/fisiologia , Velocidade do Fluxo Sanguíneo , Humanos , Angiografia por Ressonância Magnética/instrumentação , Artéria Poplítea/anatomia & histologia , Veia Poplítea/anatomia & histologia , Valores de Referência , Sensibilidade e Especificidade
18.
AJNR Am J Neuroradiol ; 20(2): 263-6, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10094349

RESUMO

Contrast-bolus tracking in the carotid bifurcation was accomplished using an MR angiographic technique with a 3D turbo field-echo readout (TR/TE = 6/3, flip angle = 50 degrees) modified by a keyhole scheme. Optimal visibility of the contrast bolus was achieved by digital subtraction from a reference volume. This technique reliably time-resolves the carotid arteries from the jugular veins.


Assuntos
Artérias Carótidas/anatomia & histologia , Meios de Contraste , Processamento de Imagem Assistida por Computador/métodos , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Artérias Carótidas/patologia , Feminino , Humanos , Masculino , Técnica de Subtração
19.
Mycopathologia ; 147(1): 49-57, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10872516

RESUMO

A total of 237 commercially available samples of cereal-based foods including bread and related products, noodles, breakfast cereals, baby and infant foods, rice and other foods were randomly collected in southwest Germany during the first six months of 1998. The trichothecenes deoxynivalenol (DON), 3- and 15-acetyl-deoxynivalenol (3-,15-ADON), nivalenol (NIV), fusarenon-X (FUS-X), T-2 toxin (T-2) and HT-2 toxin (HT-2) were determined by gas chromatography/mass spectrometry following clean-up by a two stage solid-phase extraction. Detection limits ranged between 2 and 12 micrograms/kg. Based on all samples, the incidence of DON, HT-2, T-2, 3-ADON, 15-ADON, and NIV was at 71, 18, 4, 4, 4 and 2%, respectively; the average contents in positive samples were at 103, 16, 14, 17, 24 and 109 micrograms/kg, respectively. Fus-X was not detected in any sample. A lower (P < 0.05) DON content was found in baby and infant foods as well as in cookies and cakes compared to bread. Overall, based on the incidence and level of all six toxins, the degree of contamination was lowest in baby and infant foods. Foods produced from either white or whole grain flour did not differ (P > 0.05) with regard to the incidence and level of DON. In foods produced from cereals of organic production both the incidence and median content of DON was lower compared to conventional production. Zearalenone, alpha- and beta-zearalenol were determined by high performance liquid chromatography in 20 selected samples, mostly baby and infant foods. These toxins were not present in excess of the detection limit in any sample.


Assuntos
Grão Comestível/microbiologia , Microbiologia de Alimentos , Fusarium/crescimento & desenvolvimento , Micoses/microbiologia , Micotoxinas/análise , Pão/microbiologia , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão , Fusarium/química , Cromatografia Gasosa-Espectrometria de Massas , Alemanha , Humanos , Alimentos Infantis/microbiologia , Oryza/microbiologia , Secale/microbiologia , Espectrometria de Fluorescência , Toxina T-2/análogos & derivados , Toxina T-2/análise , Tricotecenos/análise , Triticum/microbiologia , Zea mays/microbiologia , Zearalenona/análise , Zeranol/análogos & derivados , Zeranol/análise
20.
J Magn Reson Imaging ; 8(6): 1334-7, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9848748

RESUMO

We investigated the feasibility of performing black-blood MR angiography (MRA) with the gradient and spin-echo (GRASE) pulse sequence. Phantom experiments and human testing were conducted, and the results were compared with those of turbo spin-echo (TSE). We demonstrated that both techniques are able to produce signal suppression of flowing fluid to background level. With fewer radiofrequency (RF)-refocusing pulses, GRASE pulse sequences could serve as an alternative black-blood technique of reduced RF power exposure and shorter scan time. These relative advantages of GRASE may become useful when high-resolution images are taken.


Assuntos
Encéfalo/irrigação sanguínea , Artérias Cerebrais/fisiologia , Veias Cerebrais/fisiologia , Imagem Ecoplanar , Angiografia por Ressonância Magnética , Velocidade do Fluxo Sanguíneo , Humanos , Imagens de Fantasmas
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