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1.
Skin Res Technol ; 23(4): 602-606, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28513053

RESUMO

BACKGROUND: Acute radiation dermatitis (ARD) is a frequent complication after breast cancer radiotherapy and is usually assessed by semi-quantitative clinical scores, which may be subject to inter-observer variability. High-frequency ultrasound imaging of the skin can reliably quantify thickness and edema in diseased skin. We aimed to compare the relative increase in dermal thickness of the irradiated zone in breast-cancer patients undergoing radiotherapy, with clinical severity. METHODS: A consecutive series of patients undergoing treatment for breast cancer by lumpectomy and radiotherapy in a 6-month period also underwent clinical and ultrasound evaluation of ARD. RESULTS: We included 34 female patients 17 had grade 1 (group 1), 17 had grade 2 or grade 3 ARD (group 2). The mean relative increase in dermal thickness in irradiated skin (RIDTIS) was greater for group 2 than 1: 0.53 vs 0.29 mm (P=.023). On univariate analysis, ARD was associated with skin phototype, breast volume and RIDTIS, and on multivariable analysis, breast volume and age remained predictive of the disease. CONCLUSION: Patients with more severe dermatitis showed significantly increased dermal thickness. Dermal thickness is a quantitative variable that could help quantify the efficacy of drugs and improve the treatment of this disease in patients undergoing radiotherapy.


Assuntos
Neoplasias da Mama/radioterapia , Radiodermite/diagnóstico por imagem , Doença Aguda , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Curva ROC , Radiodermite/etiologia , Ultrassonografia
2.
Ultrasound Obstet Gynecol ; 48(6): 779-785, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26678354

RESUMO

OBJECTIVE: To analyze the anatomical relationship between the pubic symphysis and the ischial spines to determine reliable landmarks for the assessment of fetal head descent by intrapartum translabial ultrasound (ITU). METHODS: All computed tomography (CT) scans performed for breech presentation and for twin delivery between 2006 and 2014 in a tertiary university hospital were obtained for measurement and analysis by two operators. The symphysis-left ischial spine angle (SIA) and the symphysis-left ischial spine distance (SID) were measured on three-dimensional reconstructions from the CT volume dataset. We calculated intra- and interobserver agreements for SIA and SID with 95% prediction intervals, created Bland-Altman plots with 95% limits of agreement and estimated the intraclass correlation coefficient (ICC). A sagittal plane projection from the SIA enabled calculation of a sagittal angle, corresponding to the angle of progression (AoP) on ITU. RESULTS: SIA and SID were obtained from CT images from 458 women. Reproducibility was good for both SIA (intraobserver ICC, 0.94 (95% CI, 0.88-0.97) and interobserver ICC, 0.81 (95% CI, 0.66-0.92)) and SID (intraobserver ICC, 0.92 (95% CI, 0.82-0.97) and interobserver ICC, 0.83 (95% CI, 0.73-0.92)). The median SIA was 106° (interquartile range (IQR), 105-109°) and median SID was 26.1 (IQR, 23.4-29.5) mm. SIA and SID were not correlated with pelvic diameter or height. The 50th percentile of AoP was 110°. CONCLUSION: Knowledge of the anatomical relationship between the pubic symphysis and ischial spines makes it possible to establish a sonographic method for assesssing fetal head descent by taking into account the level of the ischial spines. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.


Assuntos
Cabeça/diagnóstico por imagem , Ísquio/anatomia & histologia , Sínfise Pubiana/anatomia & histologia , Tomografia Computadorizada por Raios X/métodos , Ultrassonografia Pré-Natal/métodos , Adulto , Feminino , Cabeça/embriologia , Humanos , Ísquio/diagnóstico por imagem , Idade Materna , Imagem Multimodal , Gravidez , Terceiro Trimestre da Gravidez , Sínfise Pubiana/diagnóstico por imagem , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
3.
Skin Res Technol ; 20(3): 274-81, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24283509

RESUMO

BACKGROUND: Complex decongestive physiotherapy (CDP) is used to treat patients with severe lymphoedema. The efficacy of CDP is usually quantified by calculating limb volume from repeated measurements of circumference at least 10 points before and after treatment of an affected limb. Measurement is time-consuming and operator-dependent. OBJECTIVES: To determine whether decreased dermal thickness is correlated with decreased volume after intensive CDP. METHODS: A consecutive series of patients admitted for intensive CDP were studied over a 6-month period. Before and after CDP, we measured circumference, dermal thickness elasticity and finally improvement in quality of life using a visual analogue scale (VAS). RESULTS: Thirty patients were included in the study. Only three patients were previously untreated. The average relative reduction in limb volume was 4% and the reduction in the dermal thickness was 15% (correlation: r = 0.37, P = 0.05). Viscoelasticity was decreased by 13%. VAS quality of life score was improved by 30%. CONCLUSION: Changes in dermal thickness are slightly correlated with volume changes before and after 5-day intensive CDP in a selected series of patients previously treated at home.


Assuntos
Linfedema/diagnóstico , Linfedema/tratamento farmacológico , Descongestionantes Nasais/uso terapêutico , Pele/diagnóstico por imagem , Pele/fisiopatologia , Ultrassonografia/métodos , Monitoramento de Medicamentos , Módulo de Elasticidade/efeitos dos fármacos , Feminino , Humanos , Linfedema/fisiopatologia , Masculino , Pessoa de Meia-Idade , Exame Físico/métodos , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
4.
Nature ; 449(7164): E1-2, 2007 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-17943088

RESUMO

An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85) in the Virgo cluster was discovered by Kulkarni et al. on 7 January 2006 that had very low luminosity (peak absolute R-band magnitude M(R) of about -12) that was constant over more than 80 days, red colour and narrow spectral lines, which seem inconsistent with those observed in any known class of transient events. Kulkarni et al. suggest an exotic stellar merger as the possible origin. An alternative explanation is that the transient in M85 was a type II-plateau supernova of extremely low luminosity, exploding in a lenticular galaxy with residual star-forming activity. This intriguing transient might be the faintest supernova that has ever been discovered.

5.
Nature ; 447(7146): 829-32, 2007 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-17568740

RESUMO

The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations.

6.
Nature ; 442(7106): 1011-3, 2006 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-16943831

RESUMO

Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes--analogues of GRBs, but with lower luminosities and fewer gamma-rays--can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae.

8.
Ann Rheum Dis ; 67(1): 31-6, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17267515

RESUMO

OBJECTIVES: There is increasing concern about heart and pulmonary vascular involvement in systemic sclerosis (SSc). One of the most severe complications of SSc is pulmonary arterial hypertension (PAH). There has been an increased awareness of left ventricular (LV) diastolic abnormalities in SSc patients. However, previous studies have generally been conducted in small populations. The aims of this study were to prospectively screen for PAH and to describe echocardiographic parameters in a large group of SSc patients. METHODS: This prospective study was conducted in 21 centres for SSc in France. Patients without severe pulmonary function abnormalities, severe cardiac disease and known PAH underwent Doppler echocardiography performed by a reference cardiologist. RESULTS: Of the 570 patients evaluated, PAH was suspected in 33 patients and was confirmed in 18 by right heart catheterisation. LV systolic dysfunction was rare (1.4%). LV hypertrophy was found in 22.6%, with LV diastolic dysfunction in 17.7%. These LV abnormalities were influenced by age, gender and blood pressure. We identified a small group of 21 patients with a restrictive mitral flow pattern in the absence of any other cardiopulmonary diseases, suggesting a specific cardiac involvement in SSc. CONCLUSIONS: Left and right heart diseases, including PAH, LV hypertrophy and diastolic dysfunction, are common in SSc. However, a small subset of patients without any cardiac or pulmonary diseases have a restrictive mitral flow pattern that could be due to primary cardiac involvement of SSc. The prognostic implications of the LV abnormalities will be evaluated in the 3-year follow-up of this cohort.


Assuntos
Cardiopatias/diagnóstico por imagem , Escleroderma Sistêmico/diagnóstico por imagem , Idoso , Cateterismo Cardíaco , Diástole , Ecocardiografia Doppler/métodos , Feminino , França , Cardiopatias/complicações , Humanos , Hipertensão Pulmonar/complicações , Hipertensão Pulmonar/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/complicações , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/complicações , Insuficiência da Valva Mitral/diagnóstico por imagem , Estudos Prospectivos , Escleroderma Sistêmico/complicações , Disfunção Ventricular Esquerda/complicações , Disfunção Ventricular Esquerda/diagnóstico por imagem
9.
AJNR Am J Neuroradiol ; 39(2): 323-330, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29170270

RESUMO

BACKGROUND AND PURPOSE: Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations. MATERIALS AND METHODS: Radiologic images and demographic data were acquired for 25 patients with bifurcation aneurysms treated with flow-diverter stents. Whisker plots and Mann-Whitney rank sum tests were used to evaluate if anatomic data and caliber changes could be linked. Symmetry/asymmetry were defined as diameter ratio 1 = symmetric and diameter ratio <1 = asymmetric. Computational fluid dynamics was performed on idealized and patient-specific anatomies to evaluate flow changes induced by flow-diverter stents in the jailed vessel. RESULTS: Statistical analysis identified a marked correspondence between asymmetric bifurcation and caliber change. Symmetry ratios were lower for cases showing narrowing or subacute occlusion (medium daughter vessel diameter ratio = 0.59) compared with cases with posttreatment caliber conservation (medium daughter vessel diameter ratio = 0.95). Computational fluid dynamics analysis in idealized and patient-specific anatomies showed that wall shear stress in the jailed vessel was more affected when flow-diverter stents were deployed in asymmetric bifurcations (diameter ratio <0.65) and less affected when deployed in symmetric anatomies (diameter ratio ∼1.00). CONCLUSIONS: Anatomic data analysis showed statistically significant correspondence between caliber changes and bifurcation asymmetry characterized by diameter ratio <0.7 (P < .001). Similarly, computational fluid dynamics results showed the highest impact on hemodynamics when flow-diverter stents are deployed in asymmetric bifurcations (diameter ratio <0.65) with noticeable changes on wall sheer stress fields. Further research and clinical validation are necessary to identify all elements involved in vessel caliber changes after flow-diverter stent procedures.


Assuntos
Circulação Cerebrovascular , Hemodinâmica/fisiologia , Aneurisma Intracraniano/terapia , Stents/efeitos adversos , Idoso , Feminino , Humanos , Hidrodinâmica , Masculino , Pessoa de Meia-Idade , Modelos Cardiovasculares
10.
Trials ; 18(1): 306, 2017 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-28683837

RESUMO

BACKGROUND: Interventional radiology includes a range of minimally invasive image-guided diagnostic and therapeutic procedures that have become routine clinical practice. Each procedure involves a percutaneous needle insertion, often guided using computed tomography (CT) because of its availability and usability. However, procedures remain complicated, in particular when an obstacle must be avoided, meaning that an oblique trajectory is required. Navigation systems track the operator's instruments, meaning the position and progression of the instruments are visualised in real time on the patient's images. A novel electromagnetic navigation system for CT-guided interventional procedures (IMACTIS-CT®) has been developed, and a previous clinical trial demonstrated improved needle placement accuracy in navigation-assisted procedures. In the present trial, we are evaluating the clinical benefit of the navigation system during the needle insertion step of CT-guided procedures in the thoraco-abdominal region. METHODS/DESIGN: This study is designed as an open, multicentre, prospective, randomised, controlled interventional clinical trial and is structured as a standard two-arm, parallel-design, individually randomised trial. A maximum of 500 patients will be enrolled. In the experimental arm (navigation system), the procedures are carried out using navigation assistance, and in the active comparator arm (CT), the procedures are carried out with conventional CT guidance. The randomisation is stratified by centre and by the expected difficulty of the procedure. The primary outcome of the trial is a combined criterion to assess the safety (number of serious adverse events), efficacy (number of targets reached) and performance (number of control scans acquired) of navigation-assisted, CT-guided procedures as evaluated by a blinded radiologist and confirmed by an expert committee in case of discordance. The secondary outcomes are (1) the duration of the procedure, (2) the satisfaction of the operator and (3) the irradiation dose delivered, with (4) subgroup analysis according to the expected difficulty of the procedure, as well as an evaluation of (5) the usability of the device. DISCUSSION: This trial addresses the lack of published high-level evidence studies in which navigation-assisted CT-guided interventional procedures are evaluated. This trial is important because it addresses the problems associated with conventional CT guidance and is particularly relevant because the number of interventional radiology procedures carried out in routine clinical practice is increasing. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01896219 . Registered on 5 July 2013.


Assuntos
Abdome/diagnóstico por imagem , Fenômenos Eletromagnéticos , Radiografia Intervencionista/instrumentação , Tórax/diagnóstico por imagem , Tomografia Computadorizada por Raios X/instrumentação , Protocolos Clínicos , Desenho de Equipamento , França , Humanos , Agulhas , Valor Preditivo dos Testes , Estudos Prospectivos , Punções , Doses de Radiação , Exposição à Radiação , Interpretação de Imagem Radiográfica Assistida por Computador , Radiografia Intervencionista/efeitos adversos , Radiografia Intervencionista/métodos , Projetos de Pesquisa , Software , Fatores de Tempo , Tomografia Computadorizada por Raios X/efeitos adversos
11.
J Radiol ; 87(12 Pt 2): 1920-36, 2006 Dec.
Artigo em Francês | MEDLINE | ID: mdl-17211307

RESUMO

Today manufacturers propose echographic systems with a resolution ranging from 100 microm down to 30 microm. This requires ultrasonic frequencies ranging from 20 to 60 MHz. However, when associated with an increase in the attenuation of the wave in the media this limits the applications to superficial exploration. High frequencies also bring special technological limitations mainly in the fields of transducers, electronics, and acoustic coupling. Although high-resolution echography has long remained marginal and been used for the exploration of the skin or the anterior chamber of the eye, new powerful and easy-to-use devices have recently appeared on the market. With these new products, new applications have also appeared such as the exploration of the oral cavity or small laboratory animals (mice).


Assuntos
Olho/diagnóstico por imagem , Boca/diagnóstico por imagem , Doenças Periodontais/diagnóstico por imagem , Pele/diagnóstico por imagem , Ultrassonografia/métodos , Ultrassonografia/estatística & dados numéricos , Adulto , Animais , Oftalmopatias/diagnóstico por imagem , Humanos , Camundongos , Dermatopatias/diagnóstico por imagem , Transdutores , Ultrassonografia/instrumentação
12.
Diagn Interv Imaging ; 97(4): 451-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26972282

RESUMO

PURPOSE: To evaluate the agreement between the Buscarini criteria on ultrasound (US) and multiphase contrast-enhanced multidetector-row computed tomography (MDCT) in the diagnosis and staging of liver involvement in hereditary hemorrhagic telangiectasia (HHT) (i.e., Rendu-Osler disease). To evaluate the role of variations in hepatic artery anatomy in the production of disagreement between these two imaging techniques. MATERIALS AND METHODS: This single center retrospective study included 62 patients with confirmed or suspected HHT. Each patient underwent Doppler US analyzed according to the Buscarini criteria and arterial and portal phase MDCT on the same day or one day apart. Liver involvement was classified as absent, slight, moderate or severe for each examination. Agreement was evaluated by the kappa and Bhapkar tests. Variations in hepatic arterial anatomy was analyzed by MDCT based on the Michel's classification and analysis of agreement and disagreement was performed using the Chi(2) test. RESULTS: Significant disagreement was identified between the two tests in 29 patients with κ=0.376 and a Bhapkar critical probability of P=0.0053. Staging of liver involvement was significantly more severe with MDCT in case of disagreement. A variant hepatic artery anatomy was identified in 12 patients with agreement and 7 patients with disagreement, but the difference was not significant (Chi(2)=0.297). CONCLUSION: The results of our study confirm the importance of associating contrast-enhanced MDCT with Doppler US in the evaluation of liver involvement in patients with HHT.


Assuntos
Hepatopatias/diagnóstico por imagem , Hepatopatias/etiologia , Tomografia Computadorizada Multidetectores , Telangiectasia Hemorrágica Hereditária/complicações , Ultrassonografia Doppler em Cores , Adulto , Idoso , Feminino , Humanos , Masculino , Estudos Retrospectivos
13.
J Radiol ; 86(6 Pt 1): 639-44, 2005 Jun.
Artigo em Francês | MEDLINE | ID: mdl-16142027

RESUMO

PURPOSE: A new matrix-based quantitative ultrasound (QUS) device was developed for the assessment of two parameters: BUA (Broadband Ultrasound Attenuation) and SOS (Speed Of Sound). This device, called Beam scanner, is a contact imaging device designed to evaluate the calcaneus. The aim of this preliminary study was to evaluate the reproducibility of results in a sample of patient with heterogeneous age distribution. MATERIALS AND METHODS: Seventy-six subjects were included: 18 healthy young males, 18 healthy young women and 40 women aged over 50 years old, including 19 osteoporotic patients according to WHO criteria. Five measurements were made for each patient after foot repositioning. Short-term precision was estimated using the coefficient of variation (CV), standardized CV (SCV) and intra-class correlation coefficient (ICC). RESULTS: SCV varied with the group of subjects between 2.0 and 4.3% for BUA, and between 3.1 and 4.5% for SOS. Mean values of BUA and SOS were statistically lower for osteoporotic women compared with healthy young women or healthy young males (p<0.001). For BUA, only SCV and ICC were better for women aged over 50 years old but without statistical difference. CONCLUSION: This study shows that the heterogeneity of the studied sample population is not a significant factor when assessing precision. This new device has a precision similar to others QUS devices.


Assuntos
Calcâneo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/instrumentação , Absorciometria de Fóton , Adulto , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Feminino , Humanos , Processamento de Imagem Assistida por Computador/normas , Masculino , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/diagnóstico por imagem , Reprodutibilidade dos Testes , Ultrassonografia/instrumentação , Ultrassonografia/normas
14.
J Fr Ophtalmol ; 38(7): 595-606, 2015 Sep.
Artigo em Francês | MEDLINE | ID: mdl-25997682

RESUMO

PURPOSE: To assess the effects of preoperative patient characteristics on clinical outcomes of corneal collagen crosslinking (CXL) in patients with progressive keratoconus. PATIENTS AND METHODS: Fifty-four eyes of 41 patients underwent CXL for progressive keratoconus between June 2011 and December 2012. Corneal topography (Orbscan(®)) was assessed at 1, 3, and 6 months and 1 year after CXL treatment and compared with preoperative data. RESULTS: A significant improvement in 1-year postoperative best-corrected visual acuity (BCVA) (0.16±0.21 LogMar preoperatively versus 0.09±0.16 LogMar postoperatively, P=0.007) and in 3mm topographic central irregular astigmatism (P=0.04) was demonstrated with CXL. No significant change was noted for refractive astigmatism (P=0.69), or for 1-year postoperative Kmax (48.4 D±4.1 at baseline versus 48.5 D±4.1 postoperatively, P=0.46). Predictive factors for BVCA improvement were low preoperative BCVA, high refractive astigmatism and advanced keratoconus. Predictive factors for stability of postoperative Kmax values were early keratoconus, and central cone ("nipple" morphology of the cone mainly located in the central 3mm of the cornea). CONCLUSION: This retrospective study confirms the efficacy of CXL for progressive keratoconus, from a refractive as well as topographic standpoint. While cone localization or its eccentricity seems to explain the variability of CXL efficacy reported in the literature, cone severity appears to be the main predictive factor for a lack of topographic stability after CXL treatment but must be weighted by the preferential localization of the cone (3 or 5mm central corneal zone).


Assuntos
Colágeno/efeitos da radiação , Córnea/efeitos da radiação , Ceratocone/radioterapia , Terapia Ultravioleta , Adolescente , Adulto , Astigmatismo/etiologia , Colágeno/química , Córnea/química , Opacidade da Córnea/etiologia , Paquimetria Corneana , Topografia da Córnea , Progressão da Doença , Epitélio Corneano/cirurgia , Feminino , Seguimentos , Humanos , Ceratocone/complicações , Ceratocone/patologia , Ceratocone/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , Protetores contra Radiação/uso terapêutico , Refração Ocular , Riboflavina/uso terapêutico , Resultado do Tratamento , Terapia Ultravioleta/efeitos adversos , Acuidade Visual , Adulto Jovem
15.
J Appl Physiol (1985) ; 72(3): 977-84, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1568994

RESUMO

This study examined the hemodynamic consequences of prolonged lower body positive-pressure application and their relationship to changes in the plasma concentration of the major vasoactive hormones. Six men [36 +/- 2 (SE) yr] underwent 30 min of sitting and then 3 h of 70 degrees head-up tilt. An antigravity suit was applied (60 Torr legs, 30 Torr abdomen) during the last 2 h of tilt. In a similar noninflation experiment, the endocrine responses were measured in the suited subjects tilted for 3 h. Two-dimensional echocardiography was used to calculate ventricular volume and cardiac output. Measurements were made 30 min before and 30 and 90 min after inflation. Immediately after inflation, mean arterial pressure increased by 7 +/- 2 Torr and heart rate decreased by 16 +/- 4 beats/min. Left ventricular end-diastolic volume and systolic volume increased significantly (P less than 0.05) at 30 and 90 min of inflation. Cardiac output increased after 30 min of inflation and returned to the preinflation level at 90 min. Plasma norepinephrine and plasma renin activity were maximally suppressed after 15 and 90 min of inflation, respectively (P less than 0.05). No such hormonal changes occurred during control. Plasma sodium, potassium, and osmolality remained unchanged during both experiments. Thus, prolonged application of lower body positive pressure induces 1) a transient increase in cardiac output and 2) a marked and sustained decrease in plasma norepinephrine and plasma renin activity, which reflect an inflation-induced decrease in sympathetic activity.


Assuntos
Trajes Gravitacionais , Hemodinâmica/fisiologia , Hormônios/sangue , Adulto , Pressão Sanguínea/fisiologia , Volume Sanguíneo/fisiologia , Débito Cardíaco/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Cinética , Masculino , Norepinefrina/sangue , Potássio/sangue , Renina/sangue , Sódio/sangue , Volume Sistólico/fisiologia
16.
Ultrasound Med Biol ; 18(5): 471-8, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1509622

RESUMO

High spatial resolution is required for echographic exploration of the skin, microvessels or small laboratory animals. With the scanner described here, high resolution is obtained by means of a strongly focused, wide-band 17 MHz center frequency transducer (-6 dB bandwidth: 22 MHz). The movement of this transducer above the skin provides a 6 mm wide and 5 mm deep echographic cross-section with an image rate of 15 images/s. The resolution is about 0.08 mm in axial and 0.2 to 0.3 mm in lateral directions. The device was tested on phantoms in water and in vivo on normal and pathological skin in the Department of Dermatology. With the easy-to-handle probe, explorations were made on psoriasis, basocellular carcinoma, malignant melanoma and sarcoidosis.


Assuntos
Ultrassonografia/instrumentação , Carcinoma Basocelular/diagnóstico por imagem , Humanos , Melanoma/diagnóstico por imagem , Pele/diagnóstico por imagem , Dermatopatias/diagnóstico por imagem , Neoplasias Cutâneas/diagnóstico por imagem
17.
Ultrasound Med Biol ; 27(2): 157-69, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11316524

RESUMO

Scattering parameters and histological properties of the ewe fetal lung microstructure were examined in vitro. Four groups of lamb fetuses were chosen at 80, 100, 130 and 145 days of gestation (10 lambs in all). The acoustic parameters of the lung (backscatter coefficient, integrated backscatter coefficient and effective scatterer size), texture parameter of the lung (effective density of scatterers) and a relative lung/liver maturation parameter (the integrated spectral ratio) were measured at 19 degrees +/- 2 degrees C within the frequency range 3-11 MHz. Values of integrated backscatter coefficient significantly decreased between 80 and 130 days gestation (from -73.0 +/- 5.7 dB to -84.0 +/- 0.9 dB between 3 to 7 MHz and from -70.0 +/- 0.8 dB to -81.3 +/- 0.5 dB between 5 to 11 MHz). Values of the integrated spectral ratio indicate that the echogenicity of the lung is greater than that of the liver. These values also decreased between 80 and 130 days gestation (from 10.5 +/- 1.1 dB to 5.1 +/- 0.9 dB between 3 to 7 MHz and from 10.0 +/- 0.8 dB to -6.4 +/- 0.6 dB between 5 to 11 MHz). Texture analysis showed that the K distribution is a good model to describe the envelope of the backscattered signals from the lung and the values of the effective density of scatterers that decrease between 80 and 130 days. These trends seem to be linked to the maturation of the microstructure of the lung and, particularly, to the development of respiratory terminal structures.


Assuntos
Pulmão/diagnóstico por imagem , Pulmão/embriologia , Ultrassonografia Pré-Natal/métodos , Animais , Desenvolvimento Embrionário e Fetal , Idade Gestacional , Processamento de Imagem Assistida por Computador , Fígado/diagnóstico por imagem , Fígado/embriologia , Matemática , Ovinos
18.
Ultrasound Med Biol ; 13(5): 267-74, 1987 May.
Artigo em Inglês | MEDLINE | ID: mdl-3303585

RESUMO

A system for the exploration of deep vessels is proposed. This device is based on a single 300 element linear array in which a "Doppler area" is selected to electronically steer a Doppler beam. Characteristics of the equipment are excellent and it is as easy to handle as a simple linear array scanner. A real-time spectrum analyser is used to process the Doppler signals. The probe and the associated electronics are described and some results are given to illustrate the capabilities of the device such as blood flow estimation and deep vessel studies.


Assuntos
Vasos Sanguíneos/anatomia & histologia , Ultrassonografia/métodos , Aorta/embriologia , Aorta/fisiologia , Vasos Sanguíneos/fisiologia , Desenho de Equipamento , Feminino , Feto/fisiologia , Humanos , Matemática , Gravidez , Fluxo Sanguíneo Regional , Ultrassonografia/instrumentação , Doenças Vasculares/diagnóstico
19.
Ultrasound Med Biol ; 13(6): 329-37, 1987 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3303590

RESUMO

The umbilical circulation can be investigated by Doppler ultrasound techniques very easily. The Doppler frequency spectrum from the umbilical arteries provides information on the placental circulation. The diastolic flow amplitude is directly related to the vascular resistances of the placenta (Rp). In cases of pathological pregnancies with hypertension the decrease of the diastolic flow and the increase of the resistance index Rp have been correlated with intrauterine fetal growth retardation. Fetal cerebral arteries have also been explored during normal pregnancies (n = 40). The index of cerebral resistance (Rc) as defined by Pourcelot is Rc = S-D/S (with S systolic amplitude and D diastolic amplitude) and shows variations similar to the placental index. During normal pregnancy, the cerebral index is higher than the placental index and the cerebro-placental ratio (Rc/Rp) is greater than 1. This preliminary study of both umbilical and cerebral circulation seems to demonstrate that during pathological pregnancies with hypertension (n = 21), with fetal growth retardation one of the indices, Rc or Rp may be out of the normal range but the cerebro-placental ratio (CPR) is always less than 1. However a larger number of patients should be explored in order to evaluate the clinical usefulness of such an observation.


Assuntos
Circulação Cerebrovascular , Desenvolvimento Embrionário e Fetal , Retardo do Crescimento Fetal/diagnóstico , Diagnóstico Pré-Natal , Ultrassonografia , Artérias Cerebrais/embriologia , Feminino , Humanos , Hipertensão/diagnóstico , Gravidez , Complicações Cardiovasculares na Gravidez/diagnóstico , Ultrassom
20.
Ultrasound Med Biol ; 15(2): 121-31, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2658234

RESUMO

A study of a method for exploration of microvessels is presented. Theoretical considerations taking into account the backscattering of ultrasound wave from a red cell and the attenuation versus frequency (up to 180 MHz) show that a frequency in the range of 80 to 120 MHz is most favorable for small depths of exploration (300 microns). The characteristics of the 113 MHz Doppler system which was built are described. The minimum detectable signal is 3 microV, the lateral resolution around 20 microns and the minimum length of the Doppler sample volume about 80 microns. The Doppler data are displayed in the form of a frequency spectrum. The first encouraging tests carried out using 20 microns rectangular glass capillary tubes and 50 to 150 microns microvessels of the mesentery of rat have demonstrated the resolution and the sensitivity of the system. A discussion illustrates the difficult problem of motion artefacts and the improvements which have to be made. From a technical point of view the authors think that it is possible to work with such a high frequency but there are two main difficulties: the processing of a very low frequency Doppler spectrum and the optimization of the probe (dimensions and shape).


Assuntos
Velocidade do Fluxo Sanguíneo , Microcirculação/fisiologia , Ultrassonografia/instrumentação , Animais , Artérias/fisiologia , Capilares/fisiologia , Desenho de Equipamento , Modelos Estruturais , Ratos , Ultrassonografia/métodos
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