Spatially controlled positioning of coordination polymer nanoparticles onto heterogeneous nanostructured surfaces.

Prussian Blue Analog (PBA) nanoparticles were formed on a heterogeneous nanostructured surface made of an ordered nanoperforated titanium oxide thin film deposited on a gold layer. The study of the nanocomposite film by grazing-incidence wide angle X-ray scattering, infrared spectroscopy, scanning electron microscopy and atomic force microscopy shows that the PBA particles are precisely positioned within all the perforations of the oxide film over very large surface areas. Further investigation on the formation of the PBA particles demonstrates a decisive role of a heterogeneous nucleation of the coordination polymer driven by well-adjusted surfaces energies and reactant concentrations in the spatial positioning of the PBA particles. Thanks to the well-controlled positioning of the particles within the ordered nanoperforations, the latter were successfully used as nano crucibles for the local transformation of PBA into the corresponding metal alloy by heat treatment. The thin film heterostructure thus obtained, made of ferromagnetic islands isolated by diamagnetic walls, opens interesting perspectives for the design of magnetic storage devices.

Comparison between Doppler ultrasonography and multiphase multidetector-row computed tomography in the detection of liver involvement in Rendu-Osler disease: An analysis of 62 patients.

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

Decrease of uteroplacental blood flow after feticide during second-trimester pregnancy termination with complete placenta previa: quantitative analysis using contrast-enhanced ultrasound imaging.

Contrast enhanced ultrasound (CEUS) was used to quantify the dynamic changes in uteroplacental blood flow before and after the interruption of fetal villus circulation resulting from feticide during a second trimester pregnancy termination in a patient with complete placenta previa. Quantitative analysis was performed on time-intensity curves acquired 24 h before and 48 h and 120 h after feticide and demonstrated the persistence of utero-placental blood flow with a progressive and two-step reduction in intervillous space and uteroplacental blood flow. Our results suggest that placental blood flow reduction after interruption of fetal circulation is a progressive and delayed mechanism.

[Value of contrast-enhanced ultrasound in the evaluation of indeterminate renal cysts on CT]. / Évaluation de l'apport de l'échographie de contraste dans l'analyse des kystes rénaux de nature indéterminée au scanner.

PURPOSE: To demonstrate the value of contrast-enhanced ultrasound (CEUS) in the management of Bosniak type 2F and 3 renal cysts on CT. PATIENTS AND METHODS: Retrospective study of 14 patients with 15 Bosniak type 2F and 3 renal cysts on contrast enhanced CT. All patients underwent CEUS of the kidneys after injection of SonoVue(®). Using predetermined criteria, the lesions were classified as benign, malignant or indeterminate. Patients either underwent surgery or follow-up CT at one to three years. RESULTS: From the 15 indeterminate cysts on CT, 12 were either benign (n=8) or malignant (n=4) on CEUS. From the eight cysts considered benign on CEUS, seven remained stable on follow-up CT after a minimum of one year interval and one was surgically resected and confirmed to be benign. All four cysts considered malignant on CEUS were surgically resected and three were confirmed to be malignant and one was confirmed to be benign. Three cysts were indeterminate: two lesions were surgically resected and one was benign while the other was malignant and one lesion was stable at one year follow-up CT. CONCLUSION: CEUS was able to characterize indeterminate lesions as benign or malignant in 80% of cases with 92% reliability. Twenty percent of cysts remained indeterminate on CEUS. CEUS is reliable as a complement to CT in the evaluation of Bosniak type 2F and 3 renal cysts.

[French first results using magnetic resonance-guided focused ultrasound for myoma treatment]. / Résultats préliminaires de la destruction des fibromes utérins par ultrasons focalisés contrôlée par résonance magnétique.

OBJECTIVE: Many women with myomas desire uterine conservation. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a new non-invasive therapy. We describe our early results regarding efficacy and safety of MRgFUS for the treatment of uterine leiomyomas. PATIENTS AND METHODS: Fifty-two French women, over 18 years of age, who were candidates for surgical myomectomy, hysterectomy or uterine artery embolization due to symptomatic myomas were treated by MRgFUS (ExAblate 2000(®), InSightec) and followed up for at least 6 months. Intramural or subserous myomas with a size between 4-12 cm and a T2 low intensity MRI image were selected in women with no abdominal scar and no bowel interposition. The modified symptom severity score (SSS) was examined before and after the treatment at 6 months. Second treatment rate during the first follow-up year was reported. RESULTS: No serious complications were recorded during the treatments or follow-up period. Seven women had initial failure mostly because of bowel interposition, six of them had uterine artery embolisation. The mean modified SSS value for patients before MRgFUS was 41/100 and the values diminished significantly to a mean value of 22/100. A total of 65% of women had a reduction of at least 10 points (n=22) (initial score of 41 [29; 62] and 22 [16; 46] at 6 month follow-up). Good correlation was observed between myomas destruction and the symptoms score. During the follow-up period, ten patients (19%) required invasive interventions (six hysterectomies, two embolisations and two myomectomies). The average reduction in myoma volume determined by MR imaging at 6 months after treatment was 14%. This volume reduction is poorly correlated with the myoma's treated volume of 36.4% (6-74%). CONCLUSION: MRgFUS can safely be used for symptomatic treatment and avoid the need for surgical intervention in most patients. Additional follow-up is needed to determine the long-term durability of this promising non-invasive approach and to obtain reimbursement.

[Real-time contrast-enhanced ultrasound in the evaluation of focal liver lesions: diagnostic efficacy and economical issues from a French multicentric study]. / Echographie de contraste temps réel dans la prise en charge diagnostique des lésions nodulaires hépatiques: évaluation des performances diagnostiques et de l'impact économique sur une étude multicentrique française.

The recent introduction of high-end ultrasound equipment combined with recent contrast agents provides marked improvements in the characterization of focal liver lesions as previously reported by monocentric studies. The aim of the present study was to evaluate the diagnostic performance of Contrast-Enhanced Ultrasonography (CEUS) using SonoVue as well as its medico-economic value for characterization of focal liver lesions. These nodules were not characterized on previous CT or conventional sonography. This prospective multicentric study conducted in 15 French centres found diagnostic performances similar to those reported for CT and MRI, with a concordance rate of 84.5%, sensitivity greater than 80% and specificity greater than 90% for all types of lesions. Higher acceptance was found for CEUS compared to other imaging modalities. Economical assessment based on examination reimbursment and contrast agent cost showed a lower cost for contrast ultrasound versus CT and MRI. This French multicentric study confirmed the high diagnostic value of CEUS for focal liver lesion characterization and demonstrated a lower economical impact compared to other imaging modalities such as CT and MRI.

[Elastosonography of thyroid lesions]. / Elastographie ultrasonore des lésions thyroïdiennes.

UNLABELLED: While ultrasound is the imaging modality of choice for diagnosis of thyroid lesions, characterization remains limited and tissue diagnosis frequently is required for management. The availability of additional tools such as elastography may improve lesion characterization and direct management. MATERIALS AND METHODS: A total of 96 patients (11 males and 85 females; 58+/-24 years) referred for fine needle aspiration (FNA) of mainly solid thyroid nodules 9-32 mm in diameter underwent conventional US and elastosonography. Results on elastography were correlated with histological results from FNA and classified as follows: suspected malignant lesion, suspected benign lesion, suspicious, indeterminate. RESULTS: The nodules were classified as follows: 95 nodules were soft (classes I and II) and 13 nodules were hard (classes III and IV). No cancers were detected in class and II lesions and 6 cancers were detected in class III and IV lesions. FNA provided insufficient cellular material for diagnosis in 5 class I-II nodules and 2 class III-IV nodules. CONCLUSION: Real-time elastosonography may be a useful adjunct to conventional US in the evaluation and characterization of thyroid nodules allowing identification of patients at high risk of malignancy for whom tissue diagnosis and/or close follow-up is required.

Mixed valency and magnetism in cyanometallates and Prussian blue analogues.

Prussian blue (PB) is a well-known archetype of mixed valency systems. In magnetic PB analogues {CxAy[B(CN)6]z}.nH2O (C alkali cation, A and B transition metal ions) and other metallic cyanometallates {Cx(AL)y[B(CN)8]z}.nH2O (L ligand), the presence of two valency states in the solid (either A-B, or A-A' or B-B') is crucial to get original magnetic properties: tunable high Curie temperature magnets; photomagnetic magnets; or photomagnetic high-spin molecules. We focus on a few mixed valency pairs: V(II)/V(III)/V(IV); Cr(II)/Cr(III); Fe(II)-Fe(III); Co(II)-Co(III); Cu(I)-Cu(II); and Mo(IV)/Mo(V), and discuss: (i) the control of the degree of mixed valency during the synthesis, (ii) the importance of mixed valency on the local and long-range structure and on the local and macroscopic magnetization, and (iii) the crucial role of the cyanide ligand to get these original systems and properties.

[Recent advances in contrast-enhanced ultrasound for oncology applications]. / Développements récents en imagerie ultrasonore de contraste à visée oncologique.

The combined use of high-end ultrasound units and sonographic contrast agents provide valuable information for lesion characterization and follow-up of patients under targeter treatments, especially oncologic patients. Early published results for liver pathology have created a place for this technique as a reference method leading to the publication of European guidelines. New oncologic applications have emerged over the last several years for lesions accessible by ultrasound with varied diagnostic value based on each target organ. Contrast-enhanced sonography is rapidly gaining ground for the follow-up of patients under targeted treatment, physical or drug induced, with major implications for the validation of concepts, and management of patients based on reliable early evaluation of therapeutic response to treatment. The purpose of this paper is to review recent advances in this field of sonographic imaging to better understand the role of ultrasound in oncologic pathology.

Diagnostic accuracy of contrast-enhanced ultrasound in focal lesions of the liver using cadence contrast pulse sequencing.

UNLABELLED: The purpose of this study was to assess the accuracy of Cadence Contrast Pulse Sequencing (Siemens-Acuson, CA) method with injection of SonoVue (Bracco Imaging SpA, Italy) for the detection and characterisation of focal liver lesions in comparison with a reference modality during routine use. METHODS: 138 consecutive patients (62 women, 76 men; mean age: 52 years for women and 63 years for men) corresponding to 144 examinations with 381 lesions participated in this prospective study from December 2002 to November 2003. Inclusion criteria were lesions detected by conventional US and the availability of a reference imaging examination (CT or MR imaging) within three weeks. The underlying liver lesions characterised by a reference modality (including biopsy in 29 lesions) were distributed as follows: haemangioma (n = 56), focal nodular hyperplasia (n = 27), hepatocellular carcinoma (n = 44), hepatocellular adenoma (n = 5), liver metastasis (n = 174), abscess (n = 2), cysts (n = 45), other benign lesions (n = 24) and 3 peritoneal metastases. RESULTS: A significant improvement was reported in the number of detected lesions between contrast-enhanced ultrasound and baseline ultrasonography (351 lesions versus 280 lesions, respectively, p < 0.01), whereas no significant difference was noted between contrast-enhanced ultrasound and reference imaging (351 versus 377 lesions, respectively). On the whole, contrast-enhanced ultrasound allowed a complete diagnosis in 96 % of the detected nodules with a significant improvement compared to conventional sonography in which the diagnosis was suspected in only 52 % out of these cases (p < 0.001). No significant difference was noted between contrast-enhanced ultrasound and the reference modality concerning characterisation of nodules. CONCLUSION: The present study clearly indicates that contrast-enhanced sonography using Sonovue and Cadence Contrast Pulse Sequencing allows real-time imaging with high accuracy and thus will be a competitive alternative to other modalities such as CT and MR imaging for liver imaging.

[Techniques and applications of noninvasive high-resolution ultrasound imaging]. / Techniques et applications de l'échographie haute résolution non invasive.

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

[High-resolution ultrasonography: utility in diagnosis, treatment, and monitoring dermatologic diseases]. / L'échographie cutanée haute résolution: utilité pour le diagnostic, le traitement et la surveillance des maladies dermatologiques.

Although less precise than histological examination, high-resolution skin imaging is a noninvasive technique that provides complementary information to the clinical examination: the lesion's US structure as well as its lateral and depth extension. Ultrasonography helps in diagnosis and initial management by measuring melanoma thickness (so as to remove this lesion with safety margins) before destructive treatment (cryosurgery or radiotherapy), by showing tumor limits, or by detecting subclinical recurrence during the follow-up. In this paper, ultrasound images will be correlated with clinical and histological data in various clinical situations such as tumors, edema, cutaneous infiltration, sclerous tissues, hyperlaxity, and cutaneous aging.

A posteriori respiratory gating in contrast ultrasound for assessment of hepatic perfusion.

An original strategy is proposed to minimize the impact of respiratory motion on hepatic contrast-enhanced ultrasound studies. It is based on the a posteriori triggering of dynamic image sequences. It was tested on perfusion studies acquired with a high temporal resolution (8 images s-1) to enable parametric imaging. A respiratory component was first estimated by independent component analysis. The estimation of the local minima and maxima of this curve enabled us to select two subsets of frames, corresponding to the end-of-inspiration plane and to the end-of-expiration plane. Both subsets were simultaneously analysed using factor analysis of medical image sequences. This method identified the main contrast uptake kinetics and their associated localizations. The global strategy was validated firstly on a simulated study and then applied to 11 patients' studies. In both cases, the frame selection was judged relevant and a necessary preliminary step before applying methods of parametric imaging. In conclusion, the a posteriori gating method that is proposed is a first step towards local quantification of hepatic contrast-enhanced ultrasound studies.

[Contrast ultrasound imaging in focal liver lesions: diagnostic value and guidelines]. / Echographie de contraste dans l'exploration des lésions focales hépatiques: valeur diagnostique et recommandations.

The recent introduction of high quality scanners and contrast agents for ultrasound deeply modifies diagnosis strategy in focal liver lesions by using validated criteria. Non-linear imaging methods using low mechanical index (MI<0.2) and second generation contrast agents allow real-time continuous imaging with concomitant limitation in background tIssue signal and also in agent collapse for a high quality contrast imaging giving dramatic improvement in detection and characterization of lesions. Interpretation is based on the presence of contrast agent within the lesion or not (hyper-, hypo- or isosignal) and the delay after injection (arterial, portal or parenchymal or late phase) as previously used by non-ultrasound methods. This allows an easy differentiation of benign from malignant lesions. Moreover, this allows complete characterization in 85 to 95% of all focal liver lesions and 75% in hepatocellular carcinomas. Those results markedly improve ultrasound accuracy compared to conventional sonography and so put contrast-enhanced sonography among recommended non-invasive imaging methods for focal liver lesions with changes in diagnostic strategy according to the lesion type and actual place of US methods. It is recommended to use contrast ultrasound methods in cancer staging for an optimal detection of liver metastases as well as in characterization of lesions detected during conventional sonography with a consecutive decrease of cost-diagnosis ratio.

[Value of combined conventional and contrast enhanced sonography in the evaluation of hepatic disorders]. / Apport de l'échographie de contraste et échographie conventionnelle simultanée en pathologie hépatique.

PURPOSE: To assess the value of combined conventional and contrast-material enhanced sonography for the characterization of focal liver lesions. MATERIALS AND METHODS: Simultaneous imaging with grey scale and contrast enhanced US was performed in 90 patients following Levovist injection (Schering, Berlin, Germany) using the "Agent Detection Imaging" method (ADI, Siemens-Acuson, Mountain View, USA). US scanning was performed at least 4 minutes after contrast injection with review of both grayscale and contrast enhanced modes. Results for detection and characterization of lesions were compared to the selected gold standard imaging modality (CT or MRI). RESULTS: Final diagnoses included: 20 normal examinations, 41 patients with metastases, 6 patients with hepatocellular carcinoma, 13 patients with hemangioma, 6 patients with other benign lesions, 4 patients with cysts and 6 patients with two types of lesions. Delayed phase contrast enhanced US allowed diagnosis of all lesions except for one metastasis and all hepatocellular carcinomas. While the diagnosis of hepatoma could not be confirmed, the features suggested a malignant etiology. For 7 patients with metastases, more lesions were detected at ADI (4.9 lesions) than at conventional US (1.1 lesion). For 3 patients, CT showed more lesions than ADI US (3.3 versus 1.6 lesions). The accuracy of ADI US for differentiating between benign and malignant lesions was 98.7% compared to 49.6% for conventional US (p<0.001). The total number of lesions detected at ADI US was higher (p<0.01) than at conventional US and not significantly different from that obtained by the gold standard reference methods. Complete characterization was achieved in 92.2% of cases with ADI US compared to 59.2% with conventional US (p<0.001). CONCLUSION: Contrast-material enhanced US combined with conventional US markedly improves the diagnostic accuracy of US in terms of lesion detection and characterization.

Contrast enhanced ultrasound image segmentation based on fuzzy competitive clustering and anisotropic diffusion.

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.