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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.

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

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.

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.

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.

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.

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.

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.

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).

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.

We have developed light weight miniature ultrasonic sensors for use in FHR (Fetal Heart Rate) monitoring. These sensors can be fixed to the maternal abdomen using double sided tape rounds identical to those used in ECG. It is shown that these sensors have performances comparable to traditional sensors while greatly increasing patient comfort and ergonomy in use.

Developments in medical imaging allow use of several modalities toward more effective diagnosis. Different modalities often complementary information of the explored organ. In order to take advantage of these different techniques image registration is required. In our case study, we deal with MRI and SPECT images from the same patient. The paper presents a registration approach, without any external landmarks, that proceeds in two steps. First, image segmentation is achieved by a competitive fuzzy clustering method. In the second step we seek for brain orientation, considered as an invariant feature, by principal axis computing. In order to handle pathological cases, which present missing information, we improve brain orientation detection with a possibilistic shell fitting method.

This paper deals with a new ultrasonic method based on Biot's theory to characterize bone-like porous media. For osteoporosis diagnosis, classical parameters such as the slope of the attenuation are both dependent on structure and density. Here, the authors are aiming at the identification of parameters related to the structure only. The Biot theory defines two characteristic frequencies, f/sub t/ and f/sub c/, which depend on structural parameters of the porous medium, such as porosity or pores size. However, they are not in the ultrasonic range. The authors have empirically defined two other frequencies, associated with a change in velocity. These frequencies are thought to delimit a Biot high frequency range and a diffusive range. Hydroxyapatite ceramics, calibrated in pores size, have been used for experiments. They have similar mass densities but different pore size. The results provide very low Biot frequencies in water-filled ceramics but may be promising with oil-filled ceramics. The measured empirical frequencies F/sub phase/ and F/sub TF/ are found to be well correlated with pore size.

Dosimetry and therapeutic application of [ 131 I]-Tyr3-octreotide were evaluated in three patients with metastatic paraganglioma and carcinoid tumor. The in vitro stability of [ 131 I]-Tyr3-octreotide was verified. Tumor uptake and residence time were between 0.02 and 0.1% and 0.5 to 9.8 h, respectively. The calculated tumor radiation doses were between 0.105 and 0.696 mGy · MBq −1 . No intolerance or adverse effects were observed after the therapeutic doses (3.3–6.6 GBq). A partial tumor response was obtained in one patient and no response occurred in two patients.

To enable the investigation of fetal movement in a manner similar to fetal heart rate (FHR) monitoring we have developed an apparatus (the DopFet system) that consists of a pair of miniature sensors, a 2-MHz continuous-wave directional Doppler electronic module and a laptop personal computer. One of the sensors is aimed at the fetal limbs and the other at the thorax to detect heart and upper body movements. The signals are analyzed, presented in real-time and postprocessed by software developed by us. The postprocessing software computes a number of parameters (the DopFet parameters) describing fetal movement. These parameters can be divided into two categories: parameters that describe the quantity of fetal movement (i.e., number of movements) and parameters that describe qualitative aspects of fetal movement (i.e., average movement duration). Future studies using the DopFet system will be aimed at discovering which of these parameters or combination of parameters is the best indicator of fetal well-being. We present an example of a 0.5 h recording and the results of testing on 23 volunteer mothers. These results show good sensitivity of the system compared to real-time ultrasound (US). The system detects 96% of rolling movements, 100% of flexion movements and 97% of leg movements.

The purpose of our study is to trace in vivo and during the perinatal period, the brain maturation process with exhaustive measures of the T2 relaxation time values. We also compared regional myelination progress with variations of the relaxation time values and of brain signal. T2 relaxation times were measured in 7 healthy premature newborns at the post-conceptional age of 37 weeks, using a Carr-Purcell-Meiboom-Gill sequence (echo time 60 to 150 ms), on a 2.35 Tesla Spectro-Imaging MR system. A total of 62 measures were defined for each subject within the brain stem, the basal ganglia and the hemispheric gray and white matter. The mean and standard deviation of the T2 values were calculated for each location. Regional T2 values changes and brain signal variations were studied. In comparison to the adult ones, the T2 relaxation time values of both gray and white matter were highly prolonged and a reversed ratio between gray and white matter was found. The maturational phenomena might be regionally correlated with a T2 value shortening. Significant T2 variations in the brainstem (p < 0.02), the mesencephalon (p < 0.05), the thalami (p < 0.01), the lentiform nuclei (p < 0.01) and the caudate nuclei (p < 0.02) were observed at an earlier time than they were visible on T2-weighted images. In the cerebral hemispheres, T2 values increased from the occipital white matter to parietal, temporal and frontal white matter (p < 0.05) and in the frontal and occipital areas from periventricular to subcortical white matter (p < 0.01). Maturational progress was earlier and better displayed with T2 measurements and T2 mapping. During the perinatal period, the measurements and analysis of T2 values revealed brain regional differences not discernible with T2-weighted images. It might be a more sensitive indicator for assessment of brain maturation.

Objective: This paper investigates the problems, advantages and potential applications of 20 MHz ultrasonic devices. Method: Aqueous gel and a thin appropriate membrane to enclose the front tip were used with 20 MHz probes without obvious decrease in resolution and sensitivity compared to the results obtained without a membrane and this considerably facilitates their routine use. Results: Many applications with linear scanning were evaluated in dermatology, ophthalmology (investigations of the anterior chamber of the eye, checking of corneal grafts), stomatology (detection and evaluation of periodontal disease) and in the field of measurement of very low velocities in small vessels by means of a duplex probe comprising two 20 MHz transducers: an imaging transducer and an inclined blood flow measurement transducer. Velocity profiles (velocities less than 0.50 mm/s) were measured in 100–300 μm diameter vessels using a cross-correlation method. Conclusion: The use of 20 MHz frequency limits resolution but we have shown that this frequency allows the development of easy to handle probes.

In vivo ultrasonic characterization of the skin was performed at 40 MHz by estimating the slope of the attenuation coefficient in the human dermis. The centroid algorithm was first tested on simulated backscattered RF lines with a second-order autoregressive model to carry out the spectral analysis. A relative error of less than 8.5% and a relative precision of less than 6% were predicted for a 2-mm tissue thickness and for temporal window sizes ranging from 0.25 to 0.45 micros. In vivo measurements performed on 138 healthy volunteers yielded values of the attenuation coefficient slope ranging from 0.8 to 3.6 dB/cm MHz. A decrease was observed with advancing age, but no significant difference appeared between men and women. The results from this study suggest that this acoustic parameter shows the effect of the ageing process on normal skin tissue in vivo.

Various parameters are currently used for the semi-quantitative assessment of dopamine D 2 receptors and differ according to the delineation of the striatal region of interest (ROI) and the choice of the reference ROI. The aim of this study was to assess the value of different ROI approaches in differentiating patients with normal or increased numbers of D 2 dopamine receptors (group 1 = Parkinson's disease, n = 8) from patients with decreased dopamine D2 receptors (group 2 = other extrapyramidal syndromes, n = 9) using 123 I-iodolisuride SPET (ILIS-SPET). 123 I-iodolisuride (190 ± 31 MBq) and 99 Tc m -ethyl cysteinate dimer ( 99 Tc m -ECD) perfusion SPET were performed in the the same position, with a dual-headed gamera camera equipped with fan beam collimators. Both a geometric approach (ellipse, circle or rectangle) and an anatomical approach using the CT scan and perfusion SPET as anatomical guides were used to draw striatal and reference ROIs. A total of 33 different parameters were calculated for each patient, indicating the ratio of counts between the striatal and reference ROIs (frontal, occipital cortex or cerebellum) and the asymmetry between the right and left striatum. More significant differences between group 1 and group 2 were found by using geometric ROIs than by using anatomical ROIs. The most discriminant ratios were the caudate/occipital, caudate/frontal and striatum/occipital ratios (P = 0.001, P = 0.002, P = 0.003 respectively). A close correlation was found between the striatum/caudate and striatum/occipital ratios, but not between the striatum/frontal and striatum/occipital ratios or between the striatum/frontal and striatum/caudate ratios. We conclude that the occipital cortex is the best reference for the semi-quantitative evaluation of dopamine D 2 receptors as the frontal cortex could include some dopamine D 2 receptor-bound radioligand, and that the caudate/occipital ratio is an appropriate parameter for differentiating Parkinson's disease from non-Parkinson extrapyramidal syndrome by 1-iodolisuride SPET.

No experimental studies looked at the disturbances appearing after a neonatal focal cerebral hypoxia-ischemia (HI) when animals become adults. Using radiotelemetry, we examined the effects of neonatal focal cerebral HI on blood pressure (BP), heart rate (HR), locomotor activity (LA), body temperature (BT) levels and circadian rhythm parameters of unrestrained adult Wistar rats. At 15 weeks of age, we continuously recorded the cardiovascular and neurobehavioral parameters of HI ( n =6) and sham-operated ( n =6) rats. In adult rats, HI induced persistent hypertensive effects associated with alteration in BP circadian rhythms and pronounced decreases in mesor and percent rhythm of LA. HR and BT parameters were not significantly modified. Therefore, our results suggest that the rat cardiovascular and behavioural circadian control systems may involve several structures which present selective vulnerability to early cerebral HI.

An imaging method is presented to measure the water-diffusion coefficient. The sequence (MISSTEC) uses the simultaneous acquisition of a spin echo and several stimulated echoes with the same intensity except for diffusion weighting. The optimal number of stimulated echoes was calculated to minimize the diffusion coefficient error (D). D values obtained in vitro and in vivo were in good agreement with those from the spin-echo sequence (IntraVoxel Incoherent Motion [IVIM] method). The total acquisition time is half that of the classic IVIM method.

Background. The aim of our study was to image psoriasis plaques by ultrasound to assess the changes in psoriasis and to measure and quantify them objectively. Materials and Methods. Thirty-one psoriasis plaques were studied in 19 patients. Measurements of skin thickness were obtained with a high resolution B-mode echographic system. Results. Some changes were seen in psoriatic skin. A new structural element was observed: a wide subepidermal nonechogenic band. The other changes were a decrease in dermal echoes that were less intense and less dense, and an increase in the epidermal and dermal skin thicknesses. The skin thickness was increased in all psoriasis plaques as compared to apparently normal skin (P < 0.001). The average increase was 67% for whole skin and 200% for epidermis. Conclusions. Ultrasound imaging of psoriatic skin allowed the identification of different skin changes induced by psoriasis, and particularly, the differentiation between epidermal and dermal alterations. We presume that epidermal thickness reflects epidermal proliferation and desquamation, and the increase in the dermal and whole skin thickness reflects infiltration. We feel that ultrasound imaging of psoriatic skin is a quantitative method that is as easy and noninvasive as the psoriasis area and severity index (PASI). It could be used for following up patients with psoriasis and could achieve widespread use, especially in research protocols.

A numerical model based on Navier-Stokes equations was used in conjunction with an experimental model in rabbits to study the effects of acute intracranial hypertension on basilar artery blood flow velocity. The hypertension was induced by pressure transmission via an epidural pressure sensor inserted into a parietal intracranial opening. A critical value of half of the diastolic arterial pressure for the intracranial cerebral pressure was determined by both numerical and experimental models. At this intracranial cerebral pressure level, the total input resistance and total input compliance, determined by the numerical model, exhibited an increase of 27% and 10%, respectively, and the tissular compliance a decrease of 25% from their physiologic baseline values. When the intracranial cerebral pressure reaches the level of the diastolic arterial pressure, a zero diastolic flow is observed into the cerebral vascular system. This study validates the theoretical model, which could be used in assessing intracranial cerebral pressure noninvasively in humans when O2 pressure can be stabilized.

The purpose of this study was to compare transcranial Doppler sonography (TCD) and 99Tcm-HMPAO cerebral scintigraphy in detecting the effects of acute intracranial hypertension by pressure transmission using a previously validated model. In 20 New Zealand rabbits, cerebral blood flow velocities of basilar artery and carotid siphon were simultaneously monitored in baseline conditions and during acute intracranial hypertension by pressure transmission. This hypertension was induced by progressive steps of 5 mmHg, for a 5 min duration by elevating a saline infusion bottle connected to the subdural space. In baseline conditions, significant correlations were found between basilar artery resistive index and 99Tcm-HMPAO uptake in brain stem, r = 0.5 (p0.05) and posterior cerebral areas, r = 0.78 (p0.001). Severe intracranial hypertension equal to the diastolic arterial pressure with a cerebral perfusion pressure of 22.8 +/- 12.7 mmHg significantly decreased the basilar artery blood flow velocities and global 99Tcm-HMPAO cerebral uptake. At this level of intracranial pressure, few correlations between the two methods were observed. TCD detected relatively high blood-flow velocities in the carotid siphon appearing to result from proximal cerebral artery vasospasm. Transcranial pulsed Doppler provides data about haemodynamic changes such as hypoperfusion, vascular resistance increase in the basilar artery territory and vasospasm of the carotid siphon. 99Tcm-HMPAO scintigraphy, which has not yet been studied during intracranial hypertension, gave immediate information on local cerebral perfusion. Cerebral scintigraphy demonstrated a significant diffuse and heterogeneous decrease in cerebral blood flow, without dissociation between supratentorial and infratentorial territories, and tissue perfusion deficit owing to arterial vasospasm. TCD provides emergency investigation in patients with severe head injuries or hydrocephalus. 99Tcm-HMPAO complements TCD in cases of vasospasm and in determining an area of perfusion tissue deficit.

The problem of the two-dimensional (2-D) localization of a target by the ultrasound Doppler effect is theoretically investigated, adopting the case of a system composed of one transmitter and two receivers. Accordingly the relation between the Doppler frequency shift at each receiver and the 2-D localization of the target was established. The range R and the azimuth B are derived from the maximum likelihood Doppler signal processing. The first stage consisted in performing the localization in air, only at the left or at the right side of the line-of-sight of the system

Tomography has been a highly active research field for the last 20 years and great progress has been made in numerical reconstruction methods. This paper deals with a new method of tomographic reconstruction based on optical processing. We first present a system of acquisition by ultrasound and then the backprojection procedure which is performed by optical methods. The projections are coded by an opto-acoustic modulator and deflector into a laser beam and the image is obtained by integrating the resulting pattern over one revolution by a CCD camera. This procedure, which is entirely analogical, allows the real time reconstruction of images, the only delay being the time required for the aquisition (approximatively 1 sec.). Echotomographies obtained by this method are presented

It is proposed to use information on the direction of reflector movement and extensive filtering in the detection of fetal breathing and cardiac movements in the ultrasonic Doppler signal recorded on the surface of the material abdomen. The method appears fairly insensitive to spurious signals and allows those of interest to be distinguished without any reference technique. A decision rule for breathing and cardiac rhythm detection, incorporating movement direction, amplitude, shape and periodicity criteria, is also proposed.