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Traces of particulate radioactive iodine (

One of the main goals of haemovigilance is to gather and analyze adverse events in recipients of blood products in order to improve blood safety. The French National Blood Service has a specific role in the management of immediate adverse events: to alert to quarantine the potentially dangerous blood products from the same donation(s), to provide blood testing for the etiologic assessment and to give transfusion advice to patients. The updating of the recipient's computer file allows a better monitoring for both immediate and delayed adverse events. Finally, the French National Blood Service's correspondent of haemovigilance is responsible for donor's inquiries, especially in cases of transfusion related to bacterial contamination, severe allergy, suspicion of transfusion acute related lung injury and viral seroconversion. The management effectiveness for adverse events requires a strong collaboration between all members of the haemovigilance network.

This study aimed to compare the transfer of 2 manmade radionuclides, radiocesium (137Cs) and radiostron- tium (90Sr), from cow milk to whey and cheese in 3 different types of French cheese production with rennet coagulation. Most of the 137Cs was present in the aque- ous phase and became concentrated in the whey. For 137Cs transfer to whey, the processing factor (Pf; i.e., the ratio of the activity concentrations) ranged between 0.86 and 1.30 (n = 12). The food processing retention factor (Fr), calculated using the processing efficiency, ranged between 0.85 and 1.19 (n = 9). No statistical difference of Pf and Fr to whey is identified for 137Cs and the cheese products. The Pf calculated for 90Sr transfer to cheese ranged between 3.95 and 12.16, with significant differences depending on the type of cheese. In addition, a linear correlation is observed between 90Sr Pf to cheese and the Ca level in the cheese (r2 = 0.57). Thus, the Pf is enhanced in hard cheeses that are enriched in calcium. This is confirmed by nearly constant Fr values, ranging between 0.66 and 0.83. © American Dairy Science Association, 2009.

Resume Les ultrasons sont de plus en plus utilises en medecine pour l’examen des organes par echographie doppler. Les frequences les plus utilisees vont de 2 a 20 MHz. Le faible prix de revient et l’innocuite des ultrasons a vocation diagnostique expliquent leur large utilisation. Aujourd’hui, les ultrasons sont egalement utilises pour detruire des tumeurs et peut-etre demain pour delivrer localement des medicaments. Plusieurs equipes francaises, liees aux universites ou CHRU, au CNRS ou a l’Inserm ont mene des travaux determinants dans l’avancement des connaissances et le developpement de nouvelles methodologies cliniques. Plusieurs entreprises ou activites industrielles ont pu etre creees a partir de ces travaux. On trouvera ci-apres quelques points de repere sur ce qui fait le succes de l’imagerie ultrasonore et les techniques associees, en observant bien que le potentiel de creativite autour de l’echographie medicale s’est sans cesse renouvele.

Cerebral hypoxia-ischemia (HI) is an important cause of perinatal brain damage in the term newborn. The areas most affected are the parasagittal regions of the cerebral cortex and, in severe situations, the basal ganglia. The aim of this study was to show that the newborn piglet model can be used to produce neuropathology resulting from moderate HI insult and to monitor damage for 7 days. Two acute cerebral HI were induced in newborn Large White piglets by reducing the inspired oxygen fraction to 4% and occluding the carotid arteries. Newborn piglets were resuscitated, extubated and monitored for 7 days. (31)P magnetic resonance spectroscopy (MRS) offers the ability to monitor the severity of the HI insults. Lactate (Lac) was detected in the HI group at 2 h, 3 days and 5 days after insult by (1)H MRS. Lac/n-acetylaspartate and Lac/choline and Lac/creatine ratios increased significantly (p0.01) in the HI group 2 h after HI insults and remained high over 7 days. For the HI group, mean T(2) values increased significantly in the parietal white matter (subcortical) for 5 days after HI insult [117.5 (+/-7.4) to 158.5 (+/-19.2) at T+3 days, 167.7 (+/-15.4) at T+5 days and 160.9 (+/-10.1) at T+7 days (p0.01)]. This newborn piglet model of moderate HI brain injury with reproducible cerebral damage could be use as reference for the study of neuroprotective strategy for a period of 7 days.

Objectives To evaluate sonographic features following uterine artery embolization and to assess using ultrasound the efficacy of embolization as the primary treatment of fibroids. Design Fifty-eight women (mean age, 44.5 years; range, 33–65 years) suffering from symptoms due to fibroids (menometrorrhagia, bulk-related symptoms, pelvic pain) were followed-up after uterine artery embolization by ultrasound examination at 3 months, 6 months, 1 year and 2 years with assessment of volume and vascularization of fibroids as well as uterine vascularization. Results Fifty-eight patients were examined at 3 months, 46 at 6 months, 36 at 1 year and 19 at 2 years. Most patients were improved or free of symptoms at 3 months (90%), 6 months (92%) and 1 year (87%) and all monitored patients were free of symptoms at 2 years. Clinical failure of treatment occurred in only two cases (3%). Progressive significant reduction in fibroid size with reference to the baseline was demonstrated during follow-up from 3 months (−29%) to 24 months (−86%). Absence of intrafibroid vessels was observed in all except three cases as early as 3 months, whereas perifibroid vessels persisted in 21 cases. No changes in uterine vascularization or uterine artery resistance were noted. Conclusions Uterine artery embolization is a valuable endovascular method for the treatment of fibroids, resulting in marked reduction in fibroid size and disappearance of intrafibroid vessels without reduction in uterine vascularization which is well depicted by sonography. Copyright © 2002 ISUOG

Tritium and stable isotope (deuterium 2H and 18O) concentrations have been determined in natural waters collected from shallow lakes, wells, streams and rivers inside and in the vicinity of the former Semipalatinsk Nuclear Test Site (NE Kazakhstan). The Semipalatinsk Test Site (STS) was one of the main proving grounds for the testing of nuclear weapons by the former Soviet Union. Tritium activity concentrations have been determined by liquid scintillation counting, while hydrogen isotopic composition have been determined using a GV-Isoprime mass spectrometer coupled to an elemental analyzer. Tritium activity concentrations recorded in lake waters (in most cases >10 Bq L-1) were significantly higher than those in well, stream and the Irtysh River waters. In lake waters, enrichments in deuterium and 18O (δD and δ18O varying between –5 and –64 ‰ V-SMOW and –8.4 and +5.5 ‰ V-SMOW, respectively), and high salt concentrations, strongly suggest that significant evaporation has occurred. In contrast, deuterium and tritium signatures of common’ surface and underground waters at the STS were mostly typical of present-day isotope backgrounds of natural waters in NE Kazakhstan. In STS, come salt lakes like Bajansor and Tumatsor with elevated tritium activity from 12 to 15 Bq L-1 lie close to the Global Meteoric Water Line. The potential tritium source for these lakes is residual concentration of tritium after former nuclear test in STS. The study provides evidence to show that export of tritium from underground nuclear test areas and tritium enrichment produced by evaporation are both important determinants of tritium concentrations in standing waters on the Semipalatinsk test site.

Fetal heart rate (FHR) monitoring is widely used to evaluate fetal health and is based on the detection of movements of the fetal heart by Doppler ultrasound. Fetal health can also be evaluated by prolonged observation of body- and pseudo-respiratory movements using two-dimensional ultrasound. Fetal breathing movements are in particular considered to be an important indicator of fetal well being. Ultrasonic Doppler signals caused by movements of the fetal heart were analyzed in detail. The signals were acquired from five healthy fetuses. Minor changes in the insonification geometry gave rise to great variations in the aspects of successive heartbeats. The signals are shown to contain information on both maternal and fetal respiratory movements. This may facilitate the development of a simple method for fetal respiration monitoring coupled to standard FHR monitoring.

Mineralogical, chemical and O-isotopic analyses were performed on the clay matrices surrounding two natural fission reactors of the Oklo deposit. In the deeply preserved reactor 10 (450 m), clays are composed of hydrothermal Mg-chlorites and sudoites (Al-chlorites). The wide range of their O-isotopic compositions (from 0.0 to 15.1‰ SMOW) is consistent with crystallisation during conditions of criticality, when the reactors created a thermal gradient of 100°C/m. The temperature in the core of reactor is calculated to have been approximately 400°C. In contrast, in the shallow reactor 9 (120 m deep), vermiculitized Al-chlorites are the products of the weathering of the hydrothermal chlorites. These vermiculitized Al-chlorites are 18 O enriched ( δ 18 O =18‰ SMOW) and underwent interaction with surface fluids (−2 to −5‰). 149 Sm / 147 Sm isotopic ratios of the clays of reactor 9 show a wide dispersion (2–3 m) of the fissiogenic Sm around the reactor. The migration of the fissiogenic Sm, which is usually retained in the deep reactors, is here related to the circulation of meteoric water under oxidising conditions.

The aim of this study was to determine the influence of neonatal focal cerebral hypoxia-ischemia (HI) on sleep-waking pattern, electrocorticogram (ECoG) power spectra and locomotor activity (LA) in adult Wistar rats. Seven-day old pups were subjected to permanent unilateral ligation of the common carotid artery and transient hypoxia (8% O2). At 10 weeks of age, the extent of brain damages was evaluated by magnetic resonance imaging (MRI) and homogenous injured animals were selected before chronic implantation of radiotelemetry device. Using a single ECoG recording channel method, waking (W), paradoxical sleep (PS) and slow wave sleep (SWS) were continuously recorded for 72 h and they were semi-automatically analyzed off-line. We observed that neonatal HI triggers a cascade of events leading, in adult rats, to brain dysfunction characterized by an increase in SWS (55.0 vs. 40.2% in sham-operated rats, p

Objectives: Clinicians are more and more frequently studying fetal blood flow velocity curves recorded by Doppler ultrasound in vital organs such as the placenta and fetal brain to evaluate fetal well-being. We have therefore developed a mathematical model of the utero-placental and fetal circulations which could be used for teaching and for a better understanding of regulatory mechanisms. Methods: The model is based on two basic elements—an arterial segment and a bifurcation—and we have reproduced the major arteries of the feto-maternal circulation combining these basic elements. The mathematical model of the system is based on the Navier–Stokes equations. The peripheral areas such as the brain, kidneys and placenta are modeled by a simple Windkessel model and the model computes instantaneous flow and pressure at any point in the fetal arterial tree and the uterine arteries. Results: We have compared the computed instantaneous flow curves and pressure with in vivo data and our results agree with the findings in physiological situations and in gravidic hypertension. Conclusions: Our model provides new interesting insights into fetal hemodynamics such as a better understanding of the mismatch impedance phenomena and is a promising model for the study of blood redistribution mechanisms in hypoxic situations.

Purpose We assessed the resistance index (RI) in the superior mesenteric artery under fasting and postprandial conditions in healthy subjects and in patients with cirrhosis to determine whether the amount of change in the RI reflects the presence or severity of liver dysfunction. Methods Fifteen subjects with normal livers and 27 patients with cirrhosis underwent Doppler sonography of the superior mesenteric artery before and after ingesting a standard meal. The RI at baseline (fasting state) and the postprandial RI were compared between the 2 groups. The fasting RIs and post postprandial RIs changes in cirrhotic patients were correlated with the severity of disease. Results No difference was found between the baseline RIs in healthy (RI = 0.85) and cirrhotic subjects (RI = 0.84), nor was there a difference in baseline RIs between subgroups of cirrhotic patients according to the severity of liver disease. The RI decreased significantly (p < 0.05) after the meal in both the healthy (13%) and cirrhotic (8%) subjects, but the postprandial decrease was significantly less pronounced (p < 0.05) in cirrhotic patients than in healthy subjects. Among cirrhotic patients, there was no correlation between the postprandial decrease of the RI and severity of liver disease. Conclusions The marked decrease in the postprandial RI in the SMA in healthy subjects is generally not seen in patients with cirrhosis, and changes in the postprandial RI do not reliably predict the severity of liver dysfunction. © 1998 John Wiley & Sons, Inc. J Clin Ultrasound 26:131–136, 1998.

Study of the cardiovascular system of the human fetus is based on non-invasive measurement methods such as Doppler echography systems. The circulation conditions in fetal vessels are usually evaluated by resistance indices, giving limited physiological information on distal territories such as the placenta or the brain. To enhance the understanding of human fetal haemodynamics, a numerical model of the fetal heart has been developed, using the hydraulic-electric analogy. The model is based on a mechanical hypothesis of parallel functioning of the right and left ventricles, considered to have analogue elastance properties. Their behaviour is equivalent to that of a single ventricle ejecting an equivalent blood volume of 7 ml in the aorta. The characterisation of the equivalent ventricle is based on the determination of a set of four parameters (Emax, Vo, kv and Po) representing the maximum ventricle contractility, a reference volume, and volume and pressure constants, respectively. The model proposed is validated by studying the effects of preload and afterload variations on the fetal heart work, and by comparing the numerical results with literature and measured data. The model constitutes the first step towards a global model of the cardiovascular system of the human fetus.

Bulk elastic, piezoelectric, and dielectric constants of four lead zirconate titanate piezoceramics, Pz24, Pz26, Pz27, Pz28, and a modified lead titanate, PTS, are measured and used to theoretically compute the effective permittivity curve of each material from which the surface acoustic wave (SAW) properties are deduced. In parallel, experimental measurements of the SAW properties are carried out by using a curve fitting algorithm on the real and imaginary parts of the electrical input impedance of an unapodised single electrode SAW transducer. The SAW propagation losses are also measured using a SAW delay line. For these ceramics, the effects of a hot isostatic pressing (HIP) post sintering process on the performances of the device are also studied. All these results are discussed and show that ceramic materials, particularly PTS, have potential for SAW applications.

New methods of estimating effective macroscopic elastic constants for inhomogeneous materials have recently been proposed using elastic-wave scattering theory. However, there are few experimental measurements which allow the validation of these models. The purpose of this paper is to verify if the scattering approximation theories allow prediction of the acoustic properties of epoxy composites containing tungsten powder for various particle sizes and various volume fractions of filler. The theoretical predictions are compared with the experimental results and the different models are discussed.

The phonophoresis of digoxin was studied in vitro through human and hairless mouse skin. Sonication was carried out with continuous mode at an intensity of 1 and 3 W/cm2 and a frequency of 3.3 MHz for 10 min. Sonication at 3W/cm2 significantly increased the absorption of digoxin through mouse skin. Percutaneous penetration was not increased using an intensity of 1W/cm2 under the same experimental conditions. Enhanced digoxin penetration at 3W/cm2 can be explained by the mechanical and/or thermal action of ultrasound waves. Thermal simulation from electrical resistance increased digoxin flux in comparable amounts to those obtained by sonication at 3 W/cm2. There was no enhancement of digoxin absorption across human skin by ultrasound, probably due to dermal retention of this lipophilic drug. Further studies will be necessary to determine the relative importance of the thermal effects of ultrasound on percutaneous administration of drugs.

Resume Le metabolisme cerebral a ete abondamment etudie ces dernieres annees par spectroscopie par resonance magnetique (SRM). L'application en neonatalogie permet de suivre la maturation cerebrale ainsi que l'installation et l'evolution de la souffrance cerebrale. L'utilisation de la spectroscopie phosphore permet de quantifier les metabolites phosphoryles ; ainsi, la mesure des concentrations relatives en phosphocreatine et en phosphate inorganique constitue un element pronostique fiable quant au devenir d'un nouveau-ne ayant subi un accident hypoxoischemique. L'etude des concentrations absolues a fait l'objet de travaux recents et semble encore plus performante. La spectroscopie du proton visualise des metabolites tels que la choline, le N-acetylaspartate, le lactate ou la taurine. Son utilisation est plus recente que celle du phosphore mais les resultats montrent deja son interet en neonatalogie.

Resume Cette revue sur les potentiels evoques (PE) cognitifs chez l'enfant comporte deux volets. Le premier concerne l'apport des PE cognitifs dans les etudes du developpement normal. Les PE cognitifs varient en effet d'une part en fonction de l'âge de l'enfant et d'autre part en fonction des processus cognitifs mis en jeu lors des tâches realisees. Les etudes topographiques permettent egalement de preciser les regions du cerveau impliquees dans ces processus cognitifs specifiques. Le deuxieme volet correspond a deux exemples de pathologie developpementale (trouble de l'attention et autisme) ou les PE cognitifs permettent de mieux comprendre les dysfonctionnements qui sous-tendent les desordres cognitifs observes.

Objective: Although echotomography is a valuable method to diagnose certain acute bowel diseases, the non-specificity of the observed wall thickening is a limitation for a clear positive diagnosis in routine practice. Our hypothesis was that a wall thickening was accompanied by an increased blood flow in acute inflammatory and tumoral processes. Materials and methods: Color coded Doppler (CCD) has been used in emergency in 25 adults to objective possible changes in gastrointestinal blood flow. The final diagnosis was based on clinical records or results of surgery. Results: In the 10 control subjects, vessels were not detected in gallbladder or gastrointestinal walls. In the 25 patients (acute cholecystis, colon cancer, appendicitis, gastric lymphoma, Crohn's disease), CCD easily detected small arteries located at the periphery or within the thickened wall (one vessel in seven cases). In Crohn's disease, the presence of detected vessels would be an argument for establishing an increase in the inflammatory process. Conclusion: The presence of arterial blood flow in a thickened gastrointestinal wall is valuable for assessing a positive diagnosis of acute inflammatory or tumoral lesions.

Summary. This experiment is the first to compare cerebral vasomotor reactivity in the supra- and infra-tentorial regions in baseline conditions and during progressive acute intracranial hypertension. The increase in intracranial pressure was performed using liquid pressure transmission in two groups of 16 rabbits by elevating a saline infusion bottle connected to the subdural space. Cerebral microvessel dilation capacity was studied using acetazolamide arterial infusion during three stages of 20 min: at baseline conditions, with an intracranial pressure value equal to half the diastolic arterial pressure and with an intracranial pressure equal to the diastolic arterial pressure. The effects of acetazolamide in the basilar artery and in the carotid siphon were simultaneously monitored by transcranial Doppler sonography during all the experiments. The changes in cerebral vasomotor reactivity occurred with the same intensity and latency in both vascular compartments in baseline conditions. The maximum amplitude of changes happened 30 s later in the basilar artery than in the carotid siphon. When intracranial pressure was above half the diastolic arterial pressure, the vasomotor tone began to decrease in the carotid siphon which supplies a small region of the rabbit brain, whereas it was maintained in the basilar artery. This effect could be explained by brain tissue hypertension. Vasomotor reactivity had nearly disappeared in all the cerebral arteries investigated when intracranial hypertension was equal to the diastolic arterial pressure. These results show evidence of a direct and late effect of acute elevation of intracranial pressure on cerebral microvascular tone. This begins in the supra-tentorial region but there is an early local effect on the carotid siphon due to the brain tissue pressure.

The relationship between intracranial pressure or cerebral perfusion pressure (CPP), cerebral blood flow, and brain energy failure is unpredictable throughout the development of acute intracranial hypertension. The purpose of the present study was to correlate intracranial pressure with cerebral blood flow velocities and brain energy metabolism in adult rabbits. The acute intracranial hypertension was achieved by pressure transmission. Transcranial Doppler wave-forms were obtained from the basilar artery for monitoring cerebral blood flow velocities. 31P-Magnetic resonance spectroscopy was used to assess brain energy metabolism. The diastolic blood flow velocity began to decrease significantly (34.5%) when the intracranial pressure was equal to half the diastolic arterial pressure for a CPP of 36 +/- 18 mmHg. Circulatory cerebral resistances increased significantly (55%) for the same value of CPP. Diastolic frequency was near zero when intracranial pressure approached diastolic arterial pressure (51 +/- 12 mmHg), corresponding to a CPP of 30 +/- 15 mmHg. At the same time, only a tendency for brain energy metabolism to decrease was observed. Consequently, transcranial Doppler sonography could be proposed for the follow-up of intracranial hypertension. Magnetic resonance spectroscopy could help to monitor these patients and could be especially proposed in case of high intracranial pressure (near diastolic arterial pressure). The joint use of these two methods would help in making appropriate therapeutic decision in humans.

High resolution acoustical imaging involves hard constraints for the ultrasonic probes which are used: a high resonance center frequency, a very wide bandwidth, a good sensitivity and a strong focusing of the beam. The system which is described uses two kinds of focused transducer: a very broad band 17 MHz center frequency transducer (PZT), and a 45 MHz copolymer transducer. The focal distances are respectively 7 mm and 6 mm in water. The movement of the transducer provides a 6 mm wide and 5 mm deep echographic cross-section with at the rate of 15 images/s. The resolution is respectively at 17 MHz and 45 MHz, 80 μm and 60 μm in axial and 250 μm and 60 μm in lateral in the focal zone. The device was tested on fantoms in water and in vivo with applications in Dermatology

In certain dermatoses, the mechanical properties of the skin are markedly altered. The evaluation of these properties in-vivo requires equipment which can simultaneously measure the skin's thickness while applying a known stress to the site in question.Skin thickness can be measured with either A- or B-scan mode ultrasound, the former of which we have incorporated in a device with enables skin elasticity to be determinated. Essentially, this involves the measurement of the distance between transducer (20 Mhz) and the skin structures, before and after deformation by suction, with a resolution of 70 μm. The transducer is located inside a small, cylindrical chamber, which has a 6 mm diameter aperture below the transducer to allow contact with the skin.This device can determine, in a non-invasive way, not only which skin structures are involved in this deformation, but also the morphological variation in the subcutaneous layers and their level of involvement at different stresses. With such information, we hope to be able to propose a mechanical model and to define appropriate skin rheological parameters

The value of sonography in lung diseases such as sarcoidosis is not established. Twelve patients with pulmonary sarcoidosis and eight control subjects underwent a sonographic examination using a high frequency probe (7.5 MHz). The normal lung surface showed smooth and regular hyperechoic patterns, respiratory motions, and occasionally minute interruptions with comet tails. All patients with sarcoidosis showed various surface abnormalities, which appeared irregular and rough with coarse interruptions, producing an increase of artifacts. Nodular patterns were found in nine of 12 patients (75%). Sonography also revealed abnormalities not diagnosed by chest radiographs (n = 2). These findings could offer an complementary approach for evaluating sarcoidosis.

Approximate formulas including losses to predict the electrical impedance of a thin unloaded piezoelectric plate around antiresonant frequencies of the thickness modes have been derived. To do so, a total loss factor is defined that includes both mechanical and electrical losses. Complex electrical impedance measurements on a lead metaniobate and four PZT-type materials between 2 and 50 MHz have been performed. The total loss factors were deduced from both the peak real impedance and from the -6 dB bandwidth of the real impedance peak. Results for fundamental and harmonic thickness modes on thin plates are discussed and the five materials are compared. It is found that for these piezoceramics the total loss factor is well approximated by a linear function of frequency. Finally, a frequency-dependent loss factor is included in the KLM equivalent circuit and it is shown that the theoretical impedance curves obtained with this model are in good agreement with measurements. >

For many years Doppler ultrasound has helped to identify the cause of renal allograft dysfunction. However, Doppler examinations were often performed after the onset of acute renal failure. In the present study we used Doppler ultrasound during grafting to follow changes in renovascular resistance. As early as 30 min after the renal artery had been unclamped, the calculated resistance index (RI) at the hilar part of the renal artery was significantly higher in the group of patients who developed acute tubular necrosis (ATN) than in the group of patients with early normalization of renal function (P = 0.05). This result did not correlate with raised cold and warm ischemia times and serum creatinine level on discharge in patients who presented with ATN. RI higher than 0.730 min after unclamping allows for an identification of those grafts at greater risk for the development of ATN and should be an indication for the early introduction of intensive therapy.

Thirty-nine consecutive patients with consolidated lung confirmed radiologically underwent sonography, and their sonograms were compared with results for 100 healthy subjects. The hyperechoic line of normal aerated lung and its air artifacts showed respiratory motions ("gliding sign," n = 100). Patients with pneumonia demonstrated distinct sonographic patterns. Strong linear echoes with characteristic air artifacts (air bronchogram) and anechoic tubular structures (fluid bronchogram) were visualized in 36 of 39 patients (92.30%). The superficial lung showed a homogeneous hypoechoic band termed "superficial fluid alveolograms" (n = 39) with respiratory motions in 35 of 39 patients. We conclude that sonography can evaluate pulmonary consolidation and may provide additional roentgenographic information, especially when fluid bronchograms are visualized.

Using the noninvasive transcranial ultrasonic Doppler method, flow dynamics of the middle cerebral arteries were investigated in relation to auditory stimulations in 12 children with autistic behavior compared with 12 normal controls and 10 mentally retarded children. In normal children, auditory stimulation evoked lateralized modifications: blood flow increased and resistance index decreased on the left side; such modifications were not recorded on the right side. This pattern should indicate vasodilation mechanisms induced by changes in the metabolism of the brain areas supplied by the left middle cerebral arteries (MCA). Although less asymmetrical, this pattern was also found in the mentally retarded children. Autistic children significantly differed from these two groups. They displayed a symmetric pattern of responses with a blood flow decrease and resistance-index increase on both sides; this could suggest abnormal metabolic mechanisms induced by auditory stimulation in autistic children and could be related to the previous hypothesis of impairment in the development of cerebral lateralization in autism. These preliminary results show that transcranial Doppler ultrasonography may be a valuable and practicable tool for the noninvasive study of evoked blood flow responses in psychopathology.

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.

The relationship between intracranial hypertension and basilar artery blood flow is not well known, and it is not yet definite that the reduction of cerebral flow depends on cerebral perfusion pressure rather than microvessel compression. The purpose of the study described here was to investigate the effect of acute intracranial pressure on the basilar flow velocity, the cerebral perfusion pressure, and the systemic arterial pressure. The basilar Doppler signal was recorded continuously in 24 New Zealand rabbits by transcranial pulsed Doppler method. The acute intracranial hypertension was induced by the progressive raising, in steps of 5 mmHg, of a saline infusion bottle connected to an epidural sensor. The intracranial hypertension induced a decrease in diastolic and mean flow velocities in the basilar artery, and an increase in the resistance index. Cerebral perfusion pressure was significantly correlated with flow parameters. The basilar diastolic flow began to decrease significantly from a 35-40 mmHg intracranial pressure and for a 37 mmHg + 20 SD cerebral perfusion pressure, without significant variation of arterial pressure. Diastolic flow dropped to zero for a 53 mmHg intracranial pressure and a 30 mmHg + 15 SD cerebral perfusion pressure. These results show that high intracranial pressure values are necessary for significantly reducing basilar artery blood flow. This effect, and the increase of circulatory cerebral resistance, occurred before significant changes in systemic arterial pressure.

Intraoperative Doppler sonographic examinations were carried out on seven preterm neonates to measure cerebral blood flow velocity changes in the anterior cerebral arteries during ductus arteriosus ligation. Age at surgery was 12 +/- 6 days. Continuous recordings during the operative procedure showed a rapid increase in diastolic blood pressure (P less than 0.01), whereas systolic blood pressure was not significantly higher compared with pre-occlusion values. In the anterior cerebral arteries, ductal closure led to a decrease in resistance index of Pourcelot (mean = 1.02 +/- 0.08 vs 0.65 +/- 0.07 (P less than 0.001)) and to an increase in area under the velocity curve (mean = 3.64 +/- 0.38 vs 8.16 +/- 1.07 (P less than 0.001)). These changes were associated with a corresponding increase of the end diastolic flow velocity (P less than 0.001) but no change in the peak systolic velocity. The heart rate did not change significantly during ductal closure. TcPO2, TcPCO2 remained normal during the study period. These data indicate that changes in cerebral blood flow velocity during surgical ligation are principally determined by changes in systemic diastolic pressure. Systolic blood pressure and peak systolic flow velocity remain unchanged or slightly higher than preligation values, thereby restoring normal cerebral blood flow velocity pattern without increasing the stress on the wall of cerebral vessels and thus the risk of peri-intraventricular haemorrhage.

A model previously developed for pure 0-3 connectivity piezocomposites has been extended to 3-3 connectivity. This matrix method allows the prediction of the effective electroelastic moduli of a piezocomposite according to its connectivity. It is used to optimize composite performance by choosing the optimal constituents for each phase. A simple combination of the results for 0-3 and 3-3 connectivities allows the effective proportion of 3-3 connectivity to be defined in highly loaded 0-3 piezocomposites. This theoretical analysis has been used to evaluate effective proportions of 3-3 connectivity in five composite samples. The values obtained are shown to be a function of the ceramic volume fraction and fabrication process. The results of this study were used to optimize the fabrication process.

The effect of therapeutic doses of indomethacin versus a placebo on cerebral hemodynamics was studied in nine preterm infants using Doppler ultrasound. Three doses of indomethacin (0.2 mg/kg) induced a significant decrease in the mean frequency compared to the placebo. Heart rate, blood pressure, transcutaneous carbon dioxide tension, and transcutaneous oxygen tension remained stable throughout the study. The changes in mean frequency occurred rapidly and were sustained at significantly diminished levels for at least 1 hour. All infants were mechanically ventilated, and the increase of mean frequency secondary to suctioning was significantly attenuated after each dose of indomethacin as compared to the placebo. The results confirmed that infusion of indomethacin caused a reduction in cerebral blood flow, probably by vasoconstriction of cerebral vessels. Indomethacin also seemed to attenuate the cerebrovascular response to hypercapnia induced by endotracheal suctioning. Even so, and because of the alteration of resting cerebral hemodynamics, we do not support the recommendation that indomethacin should be used prophylactically to prevent patent ductus arterious or periventricular intraventricular hemorrhage.

The color flow mapping method makes it possible to identify small vessels presently not detected on B-mode imaging. The main cerebral arteries of normal human fetuses, anterior, middle, and posterior arteries, were investigated by color-coded Doppler in 45 normal pregnancies. The Pourcelot index R was calculated at different stages of the pregnancy. The values of R (anterior cerebral artery), R (middle cerebral artery), and R (posterior cerebral artery) were compared in each fetus. No significant differences were found when comparing all of the R (anterior cerebral artery) and R (middle cerebral artery) or the R (anterior cerebral artery) and R (middle cerebral artery) at the same gestational age. On the contrary, for each fetus, at any gestational age, the R (anterior cerebral artery) and the R (middle cerebral artery) indices were significantly different (P < 0.01); the index in the middle cerebral artery was higher than that of the anterior cerebral artery. The same difference was observed when comparing R (posterior cerebral artery) and R (middle cerebral artery). The index of the middle cerebral artery was significantly higher than that of the posterior cerebral artery (P < 0.001). On the other hand, no significant difference was found between R (anterior cerebral artery) and R (posterior cerebral artery) at any gestational age (P = 0.4).

Radioiodinated m-iodobenzylguanidine [( 125I]MIBG) and tritiated norepinephrine [( 3H]NE]) uptake and release were compared, in different regions of the brain of the rat. The classification of the regions according to uptake was the same for both tracers:striatum greater than hypothalamus greater than hippocampus greater than cortex greater than brainstem. Tetrabenazine (TBZ), a granular monoamine uptake inhibitor reduced the uptake in the different regions. The inhibition rate was higher for [3H]NE uptake than for [125I]MIBG. The spontaneous release was the same for [125I]MIBG and [3H]NE and was the lowest in the striatum. The K+ stimulated release of [3H]NE was more complete than the release of [125I]MIBG and was the most important in the striatum. From these results, it is inferred that MIBG enters the brain tissue via NE uptake mechanisms. It appears that MIBG is stored in the chromaffin granules, as NE, but also in the cytoplasm. A modified molecule derived from MIBG which would cross the blood-brain barrier, would then appear as a potential scintigraphic marker of monoamine uptake, storage and release.

Contamination of the environment by radionuclides is usually estimated using soil and grass sampling. However, radionuclides are often not homogeneously distributed in soils. In the alpine Mercantour region (Western Alps, France) a large heterogeneity in Chernobyl 137 Cs deposition has been previously observed. Here we report additional 137 Cs results together with new 90 Sr and Pu data for soil, grass, milk, and cheese samples. The results show that radioisotopes from nuclear weapons tests fallout are more homogeneously distributed than Chernobyl 137 Cs. Further, we observe that the 137 Cs and 90 Sr contents are less variable in milk samples than in grass or soil samples. This can be attributed to the homogenization effect of cow vagrancy during grazing. Hence milk seems to be a more robust sample than soil or grass to evaluate the extent of contamination on a regional scale. We explore this idea by comparing own unpublished 90 Sr results and 90 Sr results from the literature to establish the relationship between altitude of grazing and contamination of soil and milk for Western Europe. There is a significant positive correlation between soil contamination and altitude and an even closer correlation between milk 90 Sr activity ( A ) and altitude ( h ): A = A 0 + e k · h where A 0 is the expected activity of milk sampled at sea level ( A 0 = 0.064 ± 0.014 Bq g −1 Ca) and h is the altitude of grazing, k being a constant ( k = 0.95 × 10 −3 ± 0.11 × 10 −3 m −1 Bq g −1 Ca). The fact that there is less scattering in the relationship for the 90 Sr milk -altitude than for 90 Sr soil -altitude suggests, again, that milk is a well-suited sample for environmental survey. The relationship between the altitude of grazing and the 90 Sr content of milk and cheese can also be used to assess the authenticity of dairy products.

Fetal heart rate (FHR) monitoring is a crucial part of monitoring at-risk pregnancies and labor. Its aim is to detect any abnormalities that might indicate acute fetal distress and a need for rapid treatment to avoid death or serious sequelae, including cerebral handicap. The use of fetal biophysical profiles in high-risk pregnancies (gravidic hypertension, in utero infection, etc.) helps to distinguish healthy fetuses from those with chronic conditions. Fetal biophysical profile scores have been developed that integrate five biophysical parameters, one of which is derived from the FHR. The major parameters detected are the rate of fetal movements, fetal tone, fetal breathing movement and amniotic fluid volume. All of those parameters except FHR are obtained by prolonged echographic observation and cannot be used routinely. We developed in this study a new multigate multitransducer pulsed Doppler system for survey of fetal behavior. Fast Fourier transform and autocorrelation function have been used for processing and analyzing ultrasonic Doppler signals generated by fetal movements. Several parameters are analyzed in each of the 12 x 5 = 60 Doppler gates: amplitude of signals reflected by moving fetal structures, velocity, direction and amplitude of displacement of fetal structure (heart, chest, limbs). From these parameters it is possible to calculate FHR and characterize fetal activity. Preliminary in vivo results obtained in 15 pregnant women (30 to 36 wk) are very encouraging but they have yet to be confirmed in future studies. These results also demonstrate the advantages of transducers designed for improved fetal movement detection. The algorithms needs to be precise enough to allow the Actifetus system to function in real time. We now have at our disposal some algorithms that succeed in quantifying FHR and fetal movements with a signal from a given sensor at a given depth. This study confirms the feasibility of monitoring fetal movements by the Actifetus system and demonstrates the importance of the characterization of fetal rhythms (and fetal behavior). The Actifetus system will serve as a new mean for studying fetal response to environment and detecting anomalies related to fetal suffering.

International audience; This paper presents a new technique called empirical mode decomposition (EMD) applied to a multi-gate, multitransducer ultrasound Doppler system used for fetal heart monitoring. We propose this system as an alternative to the existing fetal monitoring techniques. Classical autocorrelation-based fetal heart rate (FHR) detection has been shown to be a good method to detect the FHR in normal situations. However, as this method is applied to magnitudes of the Doppler signal fails to estimate the fetal heart rate when the fetus moves. In view of the extent of FHR variability, a monitoring system should be able to estimate this parameter each time. We therefore propose empirical mode decomposition as an interesting alternative for long-term monitoring. The principle of this method consists of iterative decompositions of a signal into a sum of functions that have the same number of extrema, the same number of zero crossings, and are symmetric with respect to the local mean. When investigation of FHR using autocorrelation on the original Doppler signal fails due to fetal movement or low signal-to-noise ratio (SNR), it is frequently successful using the intrinsic mode functions (imfs). We compared the results of multi-transducer FHR detection with and without EMD decomposition using in-vivo Doppler signals from a set of 40 women between 32 and 38 weeks of pregnancy. This method greatly improved the quality of FHR detection.

Doppler has been used for many years for cardiovascular exploration in order to visualize the vessels walls and anatomical or functional diseases. The use of ultrasound contrast agents makes it possible to improve ultrasonic information. Nonlinear ultrasound imaging highlights the detection of these agents within an organ and hence is a powerful technique to image perfusion of an organ in real-time. The visualization of flow and perfusion provides important information for the diagnosis of various diseases as well as for the detection of tumors. However, the images are buried in noise, the speckle, inherent in the image formation. Furthermore at portal phase, there is often an absence of clear contrast between lesions and surrounding tissues because the organ is filled with agents. In this context, we propose a new method of automatic liver lesions segmentation in nonlinear imaging sequences for the quantification of perfusion. Our method of segmentation is divided into two stages. Initially, we developed an anisotropic diffusion step which raised the structural characteristics to eliminate the speckle. Then, a fuzzy competitive clustering process allowed us to delineate liver lesions. This method has been used to detect focal hepatic lesions (metastasis, nodular hyperplasia, adenoma). Compared to medical expert’s report obtained on 15 varied lesions, the automatic segmentation allows us to identify and delineate focal liver lesions during the portal phase which high accuracy. Our results show that this method improves markedly the recognition of focal hepatic lesions and opens the way for future precise quantification of contrast enhancement.

Doppler has been used for many years for cardiovascular exploration in order to visualize the walls and anatomical or functional diseases. The use of ultrasound contrast agents makes it possible to improve ultrasonic information. Thus, harmonic imaging is a powerful tool for characterizing pathologies by their vascularity. However, images are buried in noise. We present an approach for noise reduction and structural features enhancement based on nonlinear anisotropic diffusion, coupled with fuzzy clustering segmentation to delineate liver pathologies.

Doppler has been used for many years for cardiovascular exploration in order to visualize vessel walls as well as anatomical or functional diseases. The use of ultrasound contrast agents makes it possible to improve ultrasonic information. Recently, nonlinear imaging has emerged as a powerful tool for characterizing pathologies by studying their perfusion. In this paper, we present a new method for estimating the perfusion parameter over a sliding window in order to accurately characterize liver lesions from two-dimensional nonlinear ultrasound images. This method is inspired by the Lucas and Kanade Algorithm coupled with coherence enhancing diffusion in order to suppress the speckle and transparent motions due to the presence of contrast agents.

Doppler has been used for many years for cardiovascular exploration in order to visualize the vessels walls and anatomical or functional diseases. The use of ultrasound contrast agents makes it possible to improve ultrasonic information. Nonlinear ultrasound imaging highlights the detection of these agents within an organ and hence is a powerful technique to image perfusion of an organ in real-time. The visualization of flow and perfusion provides important information for the diagnosis of various diseases as well as for the detection of tumors. We present a new method to automatically segment hepatic tumors, during a perfusion phase, in ultrasound hepatic nonlinear imaging. It is based on a coherence enhancing diffusion process, which removes noise and raises the structural characteristics. The segmentation procedure is a fuzzy competitive agglomerative clustering which takes into account of the perfusion phenomenon. We have tested our method on clinical sequences and obtained excellent results.

Clinicians regularly use several modalities to visualize different aspects of an explored organ. Indeed, recent medical imaging progresses allow complementary information often provided by anatomical and functional modalities to be combined. So, a preliminary image registration is required. In this paper, we present a registration method of multimodal brain MRI and SPECT images of a single patient. The constraint is that no external landmark are available. Therefore, we focus on seeking anatomical invariant brain properties. Hence, we explain our method based on fuzzy image segmentation and a principal axis computing on brain orientation considered as an invariant feature. We deal also with pathological cases presenting missing information in this context. An extension of our method based on a possibilistic shell fitting technique is then developed for brain missing information cases.