Dynamic contrast-enhanced ultrasound parametric maps to evaluate intratumoral vascularization.

Objectives: The purposes of this study were to assess the reliability of parametric maps from dynamic contrast-enhanced ultrasound (DCE-US) to reflect the heterogeneous distribution of intratumoral vascularization and to predict the tissue features linked to vasculature. This study was designed to compare DCE-US parametric maps with histologic vascularity measurements.

Materials And Methods: Dynamic contrast-enhanced ultrasound was performed on 17 melanoma-bearing nude mice after a 0.

Assessment of quantitative perfusion parameters by dynamic contrast-enhanced sonography using a deconvolution method: an in vitro and in vivo study.

Objectives: The purpose of this study was to investigate the impact of the arterial input on perfusion parameters measured using dynamic contrast-enhanced sonography combined with a deconvolution method after bolus injections of a contrast agent.

Methods: The in vitro experiments were conducted using a custom-made setup consisting of pumping a fluid through a phantom made of 3 intertwined silicone pipes, mimicking a complex structure akin to that of vessels in a tumor, combined with their feeding pipe, mimicking the arterial input. In the in vivo experiments, B16F10 melanoma cells were xenografted to 5 nude mice.

In vitro evaluation of the impact of ultrasound scanner settings and contrast bolus volume on time-intensity curves.

The objective of this study was to assess in vitro the impact of ultrasound scanner settings and contrast bolus volume on time-intensity curves formed from dynamic contrast-enhanced ultrasound image loops. An indicator-dilution experiment was developed with an in vitro flow phantom setup used with SonoVue contrast agent (Bracco SpA, Milan, Italy). Imaging was performed with a Philips iU22 scanner and two transducers (L9-3 linear and C5-1 curvilinear).

Estimation of intra-operator variability in perfusion parameter measurements using DCE-US.

Aim: To investigate intra-operator variability of semi-quantitative perfusion parameters using dynamic contrast-enhanced ultrasonography (DCE-US), following bolus injections of SonoVue(®).

Methods: The in vitro experiments were conducted using three in-house sets up based on pumping a fluid through a phantom placed in a water tank. In the in vivo experiments, B16F10 melanoma cells were xenografted to five nude mice.

Combining functional imaging and interstitial pressure measurements to evaluate two anti-angiogenic treatments.

Background: Interstitial hypertension is responsible for poor capillary blood flow and hampered drug delivery. The efficacy of combined sorafenib/bevacizumab treatment given according to different administration schedules has been evaluated by measuring both interstitial pressure (IP) and quantitative dynamic contrast-enhanced ultrasonography (DCE-US) parameters in melanoma-bearing mice.

Material And Methods: [corrected] Sixty mice were xenografted with B16F10 melanoma.

Dynamic contrast-enhanced ultrasonography (DCE-US) with quantification of tumor perfusion: a new diagnostic tool to evaluate the early effects of antiangiogenic treatment.

Dynamic contrast-enhanced ultrasonography (DCE-US) using the contrast agent Sonovue and vascular recognition imaging software is a novel technique that enables the detection of microvessels and quantitative assessment of solid tumor perfusion using raw linear data. Clinical trials have shown that DCE-US can be used to assess the anticancer efficacy of antiangiogenic treatment, for which conventional efficacy criteria based on size are unsuitable. Reduction in tumor vascularization can easily be detected in responders after 1-2 weeks and is correlated with progression-free survival and overall survival.

Early quantitative evaluation of a tumor vasculature disruptive agent AVE8062 using dynamic contrast-enhanced ultrasonography.

Objectives: To evaluate the early tumor vasculature disrupting effects of the AVE8062 molecule and the feasibility of dynamic contrast-enhanced ultrasonography (DCE-US) in the quantitative assessment of these effects.

Material And Methods: AVE8062 was administered at a single dose (41 mg/kg) to 40 melanoma-bearing nude mice, which were all imaged before and after drug administration (5 + 15 minutes, 1, 6, and 24 hours). Using an ultrasound scanner (Aplio, Toshiba), intratumor vessels were counted in power Doppler mode and tumor microvasculature was assessed in a specific harmonic mode associated with a perfusion and quantification software for contrast-uptake quantification (Sonovue, Bracco).

Acoustic characterization of a new trisacryl contrast agent. Part II: Flow phantom study and in vivo quantification.

The biocompatible trisacryl particles (TMP) are made of a cross-linked acrylic copolymer. Their inherent acoustic properties, studied for a contrast agent application, have been previously demonstrated in a in vitro Couette device. To measure their acoustic behaviour under circulating blood conditions, the TMP backscatter enhancement was further evaluated on a home-made flow phantom at different TMP doses (0.

Acoustic characterization of a new trisacryl contrast agent. Part I: In vitro study.

The objective of the study was to acoustically characterize trisacryl polymeric microparticles (TMP), which are derived from biocompatible embolic agents. With significant acoustic properties, these polymeric particles could be potentially used as targeted ultrasound contrast agents, directed towards a specific site, with ligands conjugation on the polymeric network surface. In the in vitro study, a pulser/receiver (PRF of 1 kHz), associated to different transducers (5, 10 and 15 MHz), was used to measure the acoustic properties of the TMP inserted in a Couette flow device.

Methodology for quantifying interactions between perfusion evaluated by DCE-US and hypoxia throughout tumor growth.

The objective was to validate a combination of two new technologies to depict tumor physiology both temporally and spatially with dynamic contrast-enhanced sonography and an oximeter. Human cancer prostate tumors xenografted onto mice were followed for three weeks using dynamic contrast-enhanced ultrasonography (DCE-US) to detect tumor perfusion. Time intensity curves in linear data were quantified on four regions-of-interest (ROI, main tumor section and its anterior, central and posterior intra-tumoral areas) to extract three indices of perfusion.

[Imaging of melanoma: accuracy of ultrasonography before and after contrast injection for diagnostic and early evaluation of treatments].

INTEREST FOR DIAGNOSIS: High-frequency sonography (12-16 MHz) allows to visualize primary cutaneous melanomas. The maximal echographic thickness was measured and strongly correlated to the Breslow index (p< 10(-4)). Lesions were well defined with homogeneous hypoechoic echostructure.

[Current events about echography in 2006: position of the ultrasound functional imaging for the early evaluation of targeted therapeutics].

The early and functional evaluation of new treatments in oncology is a main goal. At present, technical advances in Doppler ultrasonography allow the detection of neovascularization for superficial and deep malignant tumours in order to evaluate the efficiency of new treatments such as antiangiogenic molecules. Contrast agents injection improves the efficiency of this technique and developments of perfusion softwares optimize this detection.

Combination of HIFU therapy with contrast-enhanced sonography for quantitative assessment of therapeutic efficiency on tumor grafted mice.

The objective was to evaluate treatment efficiency of a new high-intensity focused ultrasound (HIFU) prototype combining a therapeutic transducer with a sonographic probe. The optimal HIFU sequence was defined on ex vivo samples before in vivo evaluation of tumor ablation was performed by perfusion quantification after contrast agent injection. The original feature of this prototype is a 9-MHz sonographic probe in a HIFU device and connected to an Aplio (Toshiba) sonograph.

In vitro echogenicity characterization of poly[lactide-coglycolide] (plga) microparticles and preliminary in vivo ultrasound enhancement study for ultrasound contrast agent application.

Objectives: This work includes (1) the characterization of a reproducible poly[lactide-coglycolide] (PLGA) microparticle preparation with an optimial mean diameter and size distribution and (2) the preliminary in vivo ultrasonographic investigation of PLGA microparticles.

Methods: A first series of PLGA microparticle preparations (1 to 15 mum) was acoustically characterized on a hydrodynamic device to select the most appropriate for ultrasound contrast agent application. Preparations of 3-microm microparticles were selected, characterized at different doses, and then injected into 20 melanoma grafted mice for contrast-enhanced power Doppler ultrasonography evaluation.

Validation of a new method for quantifying in vivo murine tumor necrosis by sonography.

Rationale And Objectives: At present, the gold standard to evaluate tumor necrosis is histology. We described here a new method to quantify the degree of tumor necrosis by ultrasonography. This technique combines ultrasound exploration of tissue and post-treatment of the numerical sequences using a dedicated software to evaluate backscattered power within the tumor.

Application of validated ultrasound indices to investigate erythrocyte aggregation in pigs. Preliminary in vivo results.

Although some studies concerning the ultrasound (US) characterization of erythrocyte aggregation reported in the literature have been conducted in vivo, none of them has led to quantitative indices. To achieve this objective, we first finalized a method on a hydrodynamic bench. Particularly, we define a kinetic protocol consisting of applying a 200 s(-1) shear rate followed up by a rapid decrease to reach a residual shear rate between 0 to 32 s(-1).

Comparison of new ultrasound index with laser reference and viscosity indexes for erythrocyte aggregation quantification.

We have previously established new ultrasonic indexes for erythrocyte aggregation using a Couette device, and validated them toward the Rayleigh's theory and reproducibility. Two hydrodynamic protocols were applied on various suspensions and their aggregation degrees were characterized by: 1. for the decreasing shear rates protocol: the power P(US) at the nominal frequency of the transducer used; 2.

A new ultrasound principle for characterizing erythrocyte aggregation: in vitro reproducibility and validation.

Rationale And Objectives: There is no method currently available to quantify erythrocyte aggregation in vivo. In this work, using a Couette system, we defined new ultrasound indexes potentially applicable for non-invasive investigations.

Methods: Two ultrasound protocols were developed: (1) a protocol in which decreasing shear rates ranging from 200 to 1 s-1 were applied to solutions; and (2) a protocol in which a 200 s-1 shear rate was initially applied followed by stoppage of flow (a kinetics protocol).