Ultrasonic waves are more and more widely used in medicine for the examination of organs by Doppler echography. The most frequently used ultrasonic frequencies range between 2 and 20 MHz. The relatively low cost and the non-invasiveness of ultrasound explain its increasing use in patients for both diagnosis and follow-up. In the near future, strong perspectives exist for the use of ultrasound for the treatment of tumours and also for local drug delivery. Several French research teams linked to University hospitals or research institutions have conducted key works for the progress of knowledge together with the development of new clinical methods. Several business units or industrial activities have been created after these works. Some landmarks will be found in this text on the features that today make the success of ultrasonic imaging and related modes, with the emphasis of the great and constantly renewed potential of creativity linked to those waves in the human body. (C) 2009 published by Elsevier Masson SAS.

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.

Le Centre d'innovations technologiques hospitalier (CITH) ultrasons de Tours a été créé en fin d'année 2000 pour mettre en œuvre, valider et développer de nouvelles méthodes ou nouveaux concepts ultrasonores avant la mise sur le marché des matériels ou la mise en œuvre quotidienne des applications développées. Le regroupement de compétences médicales appliquées, d'encadrement, de protocoles et d'ingénierie est l'assurance pour les constructeurs de disposer d'interlocuteurs de haut niveau. Le CITH est engagé dans l'étude de nouveaux matériels tels les agents de contraste ultrasonores, l'imagerie haute fréquence en pathologie humaine (peau et œil) et exploration animale, l'exploration des mouvements fœtaux et ses relations avec l'activité maternelle et la souffrance fœtale, l'exploration de la déformabilité tissulaire par ultrasons, la détection des particules intravasculaires de taille supérieure ou d'échogénicité différente de celle des globules rouges et l'exploration de la paroi bronchique par ultrasons. Le CITH a été le déclencheur de développements nouveaux et de la mise en œuvre d'une stratégie complète dans un domaine médical associant recherche fondamentale, évaluation préclinique et applications cliniques autorisant une convergence de moyens et d'échanges essentiels pour une évaluation des méthodes ultrasonores dans le domaine médical.

Quantifier l’augmentation de zone détruite par HIFU lors de l’infusion de microbulles. Le traitement par HIFU (3MHz, 1500 W/m2) a concerné le tiers supérieur des reins droit et gauche de 10 lapins (2,5 kg) par un prototype à guidage échographique (Theraclion®, Paris). Le traitement (50 tirs sur 14 minutes, zone théorique de 430 mm3) a été effectué sans ou avec infusion de SonoVue® (0,3 ml/mn). Une mesure des volumes détruits était faite par échographie et macroscopie lors de l’autopsie à 72h. Ont été retenus 6 traitements sans et 6 traitements avec microbulles. Aucune brûlure cutanée n’a été observée. Le volume nécrosé était fortement augmenté avec microbulles (52 [14-152] versus 5 [0-18] mm3, p = 0,0065). Sans microbulles 4 reins ne présentaient pas de lésions visibles mais tous les reins traités avec microbulles présentaient une lésion détectable. Le fort accroissement de la zone traitée par ultrasons en présence de microbulles permettrait de proposer une modulation de durée ou intensité pour un plus grand confort des patients.

Evaluer la réponse corticale de l’aire visuelle de nouveau-nés au cours de la première année de vie par Doppler transcrânien (DTC). Enregistrement des vélocités des artères cérébrales moyennes et postérieures bilatérales par DTC chez 104 nouveau-nés (nés entre 26 et 34 semaines de gestation) au cours de leur première année, avant et pendant une stimulation lumineuse. Pour les enfants sans retard de développement, lors de la stimulation, avant 6 mois, quel que soit l’âge de naissance, il est noté une diminution (-10 %) des vélocités sanguines des deux côtés alors qu’à partir de 6 mois, une augmentation des vélocités sanguines (+ 8 %) est observée comme chez l’adulte. Cette augmentation est plus importante pour les artères cérébrales postérieures. Pour 4 enfants avec retard de maturation, cette augmentation des vélocités est retardée entre 6 mois et 1 an. Ces résultats suggèrent qu’il existe un délai de réponse corticale adaptée indépendant de l’âge de naissance mais plutôt d’une exposition à la lumière nécessaire de 6 mois. Ceci permettrait d’utiliser le DTC pour détecter des retards de maturation cérébrale.

Quantifier la zone détruite en HIFU par échographie de contraste dès la fin de la session thérapeutique. Le traitement par HIFU (3MHz, 1500 W/ m2, 50 tirs sur 14 minutes, zone théorique de 430 mm3) a concerné le tiers supérieur rénal de 10 lapins (2,5 kg) par un prototype à guidage échographique (Theraclion®, Paris). Une mesure des volumes détruits était effectuée par échographie conventionnelle lors de l’autopsie à 72h. A la fin de la session était réalisée une échographie de contraste (CnTI, Esaote) après bolus intraveineux de 0,3 ml de SonoVue®. Douze traitements ont été pris en compte. Le volume nécrosé moyen mesuré à 72h était de 44 ± 47 mm3. Dans aucun cas il n’a été possible de mettre en évidence une zone ischémique à l’échographie conventionnelle et de contraste à la fin de la session alors que, à 72h, ces volumes étaient clairement mesurables. L’échographie de contraste n’apparaît pas adaptée pour évaluer précocement l’effet thérapeutique des ultrasons amenant à rechercher d’autres modalités ultrasonores ou non.

Doppler has been used for many years for cardiovascular exploration in order to visualize the vessel 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 organ perfusion 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 to 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 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.

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 (p < 0.01) 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 (p < 0.01)]. 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.

L’objectif était de développer des techniques de traitement des signaux Doppler fœtaux dans le but d’évaluer le comportement du fœtus pendant la grossesse à partir de l’analyse du Rythme Cardiaque Fœtal, les mouvements pseudo-respiratoires et des mouvements globaux du fœtus. Le but final est de mettre au point un système de monitoring ambulatoire du comportement fœtal. Le matériel développé est un système multicapteur à effet Doppler puisé (Système ACTIFŒTUS) qui détecte les signaux Doppler fœtaux à 5 profondeurs successives dans l’utérus. La détection et la caractérisation de l’activité fœtale sont réalisées grâce à un traitement de signal adapté suivi de l’extraction de paramètres spécifiques. Les enregistrements effectués sur 15 patientes ont permis de montrer la qualité des signaux de l’activité fœtale obtenus avec le système ACTIFŒTUS, et de valider la FFT et l’autocorrélation pour détecter l’activité cardiaque et les mouvements du fœtus. Nous avons pu également montrer que l’ACI permet de séparer un mélange de signaux Doppler. Plusieurs exemples de résultats seront présentés. Les résultats obtenus permettent d’envisager le développement d’une méthode d’étude ultrasonore du comportement fœtal dans les conditions physiologiques, et de suivi de fœtus en situation de souffrance chronique.

(Manuscrit i-qu le 1 i fei’rirr 2003, occ.epi‘: Ir 19 .septembre 2003) 17 ans apres l’accident de Tchernobyl, cette etude propose une reconstitution des depots de 137Cs dus a cet accident sur l’ensemble du territoire fran ais metropolitain. Cette reconstitution est basee sur la relation entre les depots de ‘”CS et les pluies de la premiere semaine de mai 1986, validee sur le tiers-est du pays, et sur une modelisation de l’appauvrissement d’est en ouest des masses d’air contaminees. La carte proposee, etablie suivant la meme methode geostatistique que celle utilisee par la Commission europeenne, est coherente avec les estimations des depots de ‘37Cs dans les pays d’Europe voisins. I3’Cs deposition mapping in May 1986 over the whole French metropolitan territory. This study intends to reconstruct the I3’Cs deposition over the French territory resulting from the Chernohyl accident, 17 years after its occurrence. This reconstruction b based on the caesium fallout versus atmospheric precipitation relationship during the first week of May 1986, already determined for the Eastern France and the modelling of air masses radioactive load decreaie toward West. The deposition map is ohtained following the methodology used for the European Commission Atlas. Our map is consistent with estimated deposit over neighhouring countries.

The uptake of MIBG, a scintigraphic agent widely used in the detection of APUD tumors, was studied with a pharmacological approach on an in vitro and an in vivo models. MIBG as well as norepinephrine (NE) was taken up by human blood platelets, a model for presynaptic nerve endings amine uptake, with a thermodependant mechanism. MIBG and NE uptake was inhibited by desimipramine and reserpine. However, MIBG but not NE uptake was inhibited by fluvoxamine, a serotonin (5HT) uptake inhibitor. This suggests that MIBG is a NE and also a 5HT uptake tracer which involves uptake one and vesicular storage mechanisms. In rats treated with 6-hydroxydopamine to induced a chemical sympathectomy, we observed an inhibition of uptake similar for MIBG and NE in the heart, the salivary glands and the spleen, but no effect was observed in the liver. Some clinical inferences to best investigate specific monoamine uptake are drawn from these results.

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.

The major objective for fetal ultrasonic monitoring of pregnancies is to recognize pathological conditions with sufficient warning to enable intervention by the clinician before the occurrence of irreversible fetal lesions. For that purpose we developed a multi detector and multigate Doppler system for the study of fetal movements and fetal rhythms in high risk pregnancies. Three methods of signal and data processing have been evaluated for the analysis of ultrasonic Doppler signals generated by the movements of fetal structures: fast Fourier transform (FFT) autocorrelation function (ACF) and independent component analysis (ICA). Preliminary results obtained in 15 normal pregnancies (32-35 weeks) are shown. Recording duration for each examination was between 15 and 20 minutes.

Many Doppler imaging studies have been performed in recent years in a large number of ocular disorders because of improvements in the Doppler equipment used for detecting and measuring the low blood-flow velocities that are a requisite for the quantitative evaluation of blood flow in the orbital vessels. The ophthalmic artery, central retinal artery and vein, posterior ciliary arteries, and the superior ophthalmic vein can be easily identified using color Doppler sonography. The changes in local blood flow in these vessels assessed by spectral analysis pulsed Doppler sonography have been used to characterize and to obtain new insights into different nontumoral vascular disorders including carotid artery stenosis, central retinal vein occlusion, giant cell arteritis, glaucoma, diabetes, fistulas, and tumoral processes of the eye and orbit. Our experience has confirmed the important role of Doppler sonography in the assessment of subclinical changes in the vascular bed, in the understanding of different processes, for following up after specific treatments, and for determining the long-term prognosis of these various conditions.

BACKGROUND/AIM:Retinal vein occlusion (RVO) is one of the most frequent ocular vascular diseases and leads to severe vision impairment. Colour Doppler imaging (CDI) is the first method which allows distinct evaluation of arterial and venous velocities in RVO. CDI is valuable for diagnosis of RVO and shows the effects of isovolaemic haemodilution. Patients with RVO were monitored by CDI for 1 year in order to clarify venous and arterial involvement in the pathogenesis of this disease.METHODS:Patients with RVO were monitored prospectively for 1 year with clinical examinations, fluorescein angiography, and CDI every 3 months. 102 adults referred for RVO for less than 2 months were enrolled. Unaffected eyes were used as control. The maximum systolic and diastolic flow velocities and the resistance index (RI) were measured in the central retinal artery (CRA) and the maximum and minimum blood flow velocities in the central retinal vein (CRV).RESULTS:During the year of observation, branch retinal vein occlusion (BRVO), ischaemic central retinal vein occlusion (CRVO), and non-ischaemic CRVO had a distinct pattern of venous velocity changes. BRVO had a similar profile to that observed in controls. Venous velocities were continuously lower in central forms, with the lowest values in ischaemic occlusion. In contrast, a brief decrease in arterial diastolic velocity was observed in ischaemic CRVO at presentation, correlated with arteriovenous passage time on fluorescein angiography, but with rapid normalisation.CONCLUSIONS:CDI findings were correlated with the type of RVO at all times during follow up. CDI showed persistent impairment of central venous velocity in CRVO whereas there was a fast initial values recovery of the arterial velocity. These results using CDI show strong evidence of a primary venous mechanism in RVO.

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, I 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 I year and 19 at 2 years. Most patients were improved or free of symptoms at 3 months (90%), 6 months (92%) and I 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-zip 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 vasclarization which is well depicted by sonography.