PubMed Health⌕ Search

Biomedical subjects

François Tranquart

Publications and source records attributed to François Tranquart.

14 recordsLinked to original sources
PubMed2006

Sensitization by dietary docosahexaenoic acid of rat mammary carcinoma to anthracycline: a role for tumor vascularization.

PURPOSE: To investigate whether dietary docosahexaenoic acid (DHA), a peroxidizable polyunsaturated omega-3 fatty acids, sensitizes rat mammary tumors to anthracyclines and whether its action interferes with tumor vascularization, a critical determinant of tumor growth. EXPERIMENTAL DESIGN: Female Sprague-Dawley rats were initiated by N-methylnitrosourea to develop mammary tumors and then assigned to a control group (n = 18), receiving a supplementation of palm oil, or to a DHA group (n = 54), supplemented with a microalgae-produced oil (DHASCO, 1.5 g/d). The DHA group was equally subdivided into three subgroups with addition of different amounts of alpha-tocopherol. Epirubicin was injected weekly during 6 weeks after the largest tumor reached 1.5 cm(2), and subsequent changes in the tumor surface were evaluated. Tumor vascularization was assessed by power Doppler sonography before and during chemotherapy. RESULTS: DHA and alpha-tocopherol were readily absorbed and incorporated into rat tissues. Epirubicin induced a 45% mammary tumor regression in the DHA-supplemented group, whereas no tumor regression was observed in the control group. In the DHA group, before chemotherapy was initiated, tumor vascular density was 43% lower than in the control group and remained lower during chemotherapy. Enhancement of epirubicin efficacy by DHA was abolished in a dose-dependent manner by alpha-tocopherol, and the same trend was observed for DHA-induced reduction in tumor vascular density. CONCLUSIONS: Dietary DHA supplementation led to a reduction in tumor vascularization before the enhancement of any response to anthracyclines, suggesting that DHA chemosensitizes mammary tumors through an inhibition of the host vascular response to the tumor.

Alkylating Agents↗
PubMed2006

Role of parametric imaging in contrast-enhanced sonography of hepatic focal nodular hyperplasia.

PURPOSE: To assess the value of parametric imaging during contrast-enhanced sonographic examination in the diagnosis of focal nodular hyperplasia (FNH) of the liver. MATERIALS AND METHODS: Thirty-one patients with solitary FNH underwent contrast-enhanced sonographic examination between January 2003 and June 2004 using SonoVue and a Sequoia scanner equipped with Cadence Contrast Pulse Sequencing software. Contrast enhancement from a time sequence of perfusion frames was estimated using QontraXt software, which provides quantification of perfusion parameters. From the time-intensity curves, we obtained the following parameters: peak enhancement value, Tr (time recovery corresponding to time needed to reach 63% of the peak value), beta parameter corresponding to the exponential factor, and slope corresponding to the slope of the tangent to the arterial phase of enhancement. RESULTS: Among the 4 parameters studied, the slope of the arterial phase of enhancement was the most sensitive to image the centrifugal arterial flow originating from the central portion of the lesion, whereas peak enhancement value and Tr were the most sensitive to image full enhancement of the lesion. A blinded review revealed equivalent sensitivity in the diagnosis of FNH between the interpretation of the original videoclips and that of the parametric images. CONCLUSIONS: The results of this study show that parametric imaging can be used in place of original videoclips for clinical reporting of FNH; furthermore, it could help less-experienced sonologists diagnose FNH.

Adult↗
PubMed2006

Assessment of cyclic changes of microvessels in ovine ovaries using Sonovue contrast-enhanced ultrasound.

Our objective was to detect variations of ovarian vascularization that occur in the estrus cycle of the ewe using an IV contrast agent. Five ewes were investigated using contrast-enhanced power Doppler after Sonovue injection at day 0, 3, 5, 10 and 13 of the cycle in two successive estrus cycles. Transvaginal ultrasound monitoring of each ewe was performed after a dose of Sonovue. Parameters derived from the time-intensity curves were compared. Quantification of the enhancement and wash-in period parameters changed significantly between ovaries and between the follicular and luteal periods of the cycle. Uptake time, wash-out time, total time of enhancement and area under the curve were the parameters with the smallest variation between ovaries. Wash-out time and area under the curve are two contrast parameters that did not change with cyclic changes. Thus, using these parameters in premenopausal women will allow more accurate detection of vascular modifications that may be associated with ovarian cancer.

Animals↗
PubMed2006

Differential diagnosis of focal nodular hyperplasia with quantitative parametric analysis in contrast-enhanced sonography.

OBJECTIVES: We investigated the potential of quantitative parametric analysis in the differential diagnosis of focal nodular hyperplasia (FNH) from other hypervascularized liver focal lesions. MATERIALS AND METHODS: Eighty-five focal liver lesions (in 83 patients) were explored using contrast-enhanced ultrasound (SonoVue and Cadence Contrast Pulse Sequencing) consisting of typical FNH (n=52), hepatocellular carcinoma (n=11), hemangioma with high flow (n=8), hypervascular metastases (n=10), and hepatocellular adenoma (n=4). QontraXt software (AMID, Italy) was used here to estimate the following parameters: maximum peak value, Tr (time corresponding to time for obtaining 63% of the plateau), beta parameter corresponding to the exponential factor, and slope corresponding to the tangent value of the first phase of enhancement. These parameters were obtained from the time-intensity curves derived from the enhancement observed in 2 regions of interest corresponding, respectively, to the whole lesion and the central region only. RESULTS: A significant statistical difference (P<0.05) was found in the values of Tr, beta, and slope between FNH and other hypervascularized lesions on both the whole lesion and central region. Among these parameters, slope appeared as the most valuable whatever the region of interest, ie, central or whole lesion (P<0.01). Central region was more accurate in the differentiation of FNH and concordant with visual characterization. CONCLUSION: Quantitative parametric curve analysis of the different hypervascularized lesions confirms the depiction of the central artery in FNH and thus could help in differentiating this specific focal liver lesion from the others.

Adult↗
PubMed2006

The kidney: imaging with microbubble contrast agents.

Conventional ultrasonography of the kidney is faced by limitations due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of color Doppler for the detection of intracortical capillaries and deep pedicular vessels. Ultrasound contrast agents (USCAs) overcome these limitations, allowing the development of new applications for renal blood flow imaging and quantification. These improvements result from the increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequences for bubble-specific imaging. In radiology, the liver has been considered as the primary target for contrast because USCAs allow both detection and characterization of focal lesions. The kidney has been less studied because USCA kinetics do not provide the same obvious potential for tumor characterization, and most clinical trials for contrast-enhanced renal imaging were conducted using color Doppler. Despite this, the kidney offers promising applications as USCAs improve the detection of abnormal microvascular and macrovascular disorders. Contrast-enhanced US may become the modality of choice for diagnosis of renal artery stenosis and detection of a perfusion deficit, as well as for characterization of indeterminate renal lesions, atypical cystic lesions, and the identification of acute pyelonephritis.

Contrast Media↗
PubMed2006

Ultrasound-guided collection of amniotic fluid in pregnant rats.

Here we present an echographic method to withdraw amniotic fluid from pregnant rats. The method could be an alternative to the surgical amniotic fluid collection methods used currently. On day 18 of gestation, pregnant Sprague-Dawley rats underwent amniotic sac puncture by either surgical procedure or echographically guided method. This study evaluated the effect of the 2 collection procedures on parturition day, number of pups per litter, and weight of newborns compared with those of a control group without any fluid collection. These parameters did not differ statistically across groups. However, the echographically guided method did not require surgery or postsurgical recovery and was therefore advantageous from the perspective of animal use. Moreover ultrasound-guided collection allows experimental designs that require collection of multiple samples from the same animal during a single pregnancy.

Amniocentesis↗
PubMed2004

Contrast-enhanced sonography helps in discrimination of benign from malignant adnexal masses.

OBJECTIVE: To investigate the potential efficacy of real-time contrast-enhanced power Doppler sonography in the differentiation of benign and malignant adnexal masses in a pilot study. METHODS: Before surgical treatment, adnexal masses were prospectively evaluated with power Doppler sonography before and after injection of a contrast agent. Real-time postinjection sequences were computerized with time-intensity analysis software to determine an enhancement curve and contrast parameters. The intraobserver and interobserver reproducibilities of these criteria were assessed on a subsample. These contrast parameters were compared between benign and malignant tumors using logistic regression. Sensitivity and specificity were used to compare contrast parameters with sonographic and Doppler variables. RESULTS: Ninety-nine women were included, for a total of 101 adnexal masses. There were 23 cases of ovarian malignancies and 78 benign adnexal lesions. Our procedure had excellent intraobserver and interobserver reproducibility, with an average intraclass correlation coefficient of 0.92. The time before enhancement and intensity ratio did not reliably differentiate between the benign and malignant masses. Washout times and areas under the curves were significantly greater in ovarian malignancies than in other benign tumors (P < .001), leading to sensitivity estimates between 96% and 100% and specificity estimates between 83 and 98%. Contrast parameters had slightly higher sensitivity and slightly lower specificity when compared with transvaginal sonographic variables of the resistive index and serum cancer antigen 125 levels. CONCLUSIONS: Contrast-enhanced power Doppler imaging may easily and precisely discriminate benign from malignant adnexal lesions. Larger studies are needed to determine the appropriate use and benefits of this new procedure.

Adnexal Diseases↗
PubMed2003

Changes in tumor vascularization after irradiation, anthracyclin, or antiangiogenic treatment in nitrosomethyl ureas-induced rat mammary tumors.

PURPOSE: Changes in tumor vascularization may be involved in tumor regression after anticancer treatments. We therefore studied the relationship between tumor vascularization and tumor response according to treatment by irradiation (RT), epirubicin (EPI), or antiangiogenic agent TNP-470 in a nitrosomethyl-ureas-induced rat mammary tumor model by measuring the changes in tumor blood flow using high-frequency Power-Doppler sonography. EXPERIMENTAL DESIGN: Mammary tumors were induced in female Sprague-Dawley rats by a single s.c. injection of nitrosomethyl-ureas. After tumor areas reached 2 cm(2), the animals received four weekly injections of epirubicin (EPI group), or a single fraction of 18 Gy (RT group), or six injections of TNP-470 within 12 days (TNP group), or both (RT combined with TNP-470, RT+TNP group). Power-Doppler sonography quantification of tumor vascularization (PDI) was performed before and 12 days after initiation of treatment. Tumor shrinkage was later evaluated and compared with the early changes in PDI values. RESULTS: Compared with the control group, EPI induced an arrest in tumor growth. A similar effect was obtained with TNP-470. There was a decrease in tumor area after RT, but administration of TNP-470 combined with RT did not further enhance this effect. Changes in tumor area paralleled changes in PDI in the EPI group. Furthermore, changes in PDI 7 days after RT were associated with further tumor change in the RT groups, whereas they were independent of the antitumor effect of TNP-470. CONCLUSIONS: Changes in functional tumor vascularization evolution appeared to be closely associated with tumor regression after anticancer treatment.

Animals↗
PubMed2003

Color Doppler imaging of orbital vessels: personal experience and literature review.

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.

Arterial Occlusive Diseases↗
PubMed2003

Leiomyoma recurrence after uterine artery embolization.

PURPOSE: The purpose of this study was to evaluate the rate of leiomyoma recurrence after uterine artery embolization (UAE) for symptomatic uterine leiomyomas. MATERIALS AND METHODS: A prospective study of UAE of uterine leiomyomas has been ongoing at the authors' hospital since 1997. The recurrence rate was assessed in June 2002. Vascular access was obtained via the right common femoral artery and free-flow embolization was performed with use of 150-250- micro m polyvinyl alcohol particles and an absorbable particle sponge. Follow-up included clinical and ultrasound (US) examinations at 3, 6, and 12 months, and once per year thereafter. RESULTS: Eighty-five UAE procedures were performed between January 1997 and June 2000. Five patients were lost to follow-up. Median follow-up was 30 months (range, 2-57 months). There were six immediate failures: one technical failure, three cases of concomitant disease (one case of endometrial cancer and two cases of adenomyosis), and two cases of large subserosal leiomyomas. There were eight late failures or recurrences: one case of leiomyoma progression, seven cases of new leiomyomas. Mean time to recurrence was 27.4 months. CONCLUSIONS: Although UAE is an effective primary treatment for leiomyomas, this study recorded a recurrence rate of 10% at just more than 2 years. Clinical and US examinations are needed before UAE to exclude pedunculated submucosal leiomyomas and cancers, and must be repeated for more than 2 years after UAE to monitor patients' progress. Longer follow-up and more events are needed to define risk factors for recurrence.

Arteries↗
PubMed2003

Radiosensitivity of rat mammary tumors correlates with early vessel changes assessed by power Doppler sonography.

OBJECTIVE: To investigate the changes occurring in the vascularization of tumors during irradiation, we used a model of autochthonous mammary tumors in rats and assessed early vascular changes after irradiation by power Doppler sonography. METHODS: Mammary tumors were induced in 24 female Sprague Dawley rats by a single subcutaneous injection of N-nitroso N-methyl urea. After tumor areas reached 1 cm2, the animals received a single fraction of 18-Gy radiation or intraperitoneal saline injection. Power Doppler sonographic quantification of detected vessels was performed 1 day before irradiation and 7 days after the use of a power Doppler index of 5 different tumor imaging planes. Final tumor shrinkage was compared with early changes in the power Doppler index. Not all tumors regressed in a similar fashion. Radiosensitive tumors were defined as tumors with a greater than 50% decrease in baseline area 28 days after irradiation, whereas radioresistant tumors were tumors with a less than 50% decrease in baseline area. Statistical analysis was performed by the Mann-Whitney U test. RESULTS: Tumor area changes were similar in radioresistant and radiosensitive tumors 7 days after irradiation (-41% and -35%, respectively; P > .05, not significant), whereas reduction in the power Doppler index was significantly greater in radiosensitive tumors (mean value, -63%) than in radioresistant tumors (mean value, -12%) (P = .001). Late tumor regrowth was correlated with day 7 power Doppler index changes (P = .009). A 40% reduction in the power Doppler index at day 7 distinguished 8 of 9 radiosensitive tumors and 8 of 9 radioresistant tumors (P = .003). CONCLUSIONS: This study suggests that early changes in tumor perfusion as assessed by power Doppler sonography after tumor irradiation may precede the long-term tumor regression.

Animals↗
PubMed2002

In vivo quantitation of tumour vascularisation assessed by Doppler sonography in rat mammary tumours.

This study was designed to evaluate high-frequency power Doppler (PDS) and to quantify treatment-induced changes in an experimental autochthonous mammary tumour model in rats. A total of 13 rats with N-methyl, N-nitroso urea-induced mammary tumours were split into three courses; 6 rats were treated with epirubicin, 3 received a placebo injection and 4 had irradiation of their tumour with a direct electron beam using a single dose of 18 Gy. In all groups, treatment began when the tumour area reached at least 1 cm(2) and was preceded by the first power Doppler sonography study of the tumour (Echo #1). Echo #2 was carried out in the middle of the placebo or epirubicin treatment (after 3 weeks) or 7 days after irradiation in the irradiated group. Echo #3 was carried out at the end of placebo or epirubicin treatment or 28 days after irradiation. Then colour pixel density (CPD) and vascularity index (VI) were quantitated. Intraobserver and interobserver variability of the CPD and VI quantitation was low (r = 0.99 and 0.97, respectively, for intraobserver and interobserver variability of the CPD values). The monitoring of CPD and VI showed an increase with time during the observation period. No increase in CPD or VI was observed in treated mammary tumours (p < 0.01). Power Doppler sonography quantitation of angiogenesis is reproducible, noninvasive and feasible in this in vivo breast cancer model. The monitoring of angiogenesis according to different treatments is feasible in real-time. Further studies are needed to investigate the predictive value of CPD and VI on sensitivity of mammary tumours to anticancer treatment.

Animals↗
PubMed2001

Advances in ultrasound.

Significant advances have been recently introduced into various fields of technology, taking advantage of the use of new piezoelectric materials and the large diffusion of broadband transducers. Various types of modulation may be applied to the pulse characteristics, using single pulse, multipulse or multiline techniques, and resulting in improved spatial resolution and better penetration. Non-linear imaging uses the harmonics component, which is generated by tissues or by contrast agents. Different modalities can be used to separate harmonics from fundamental bands from the received signal. New Doppler modes have been developed, whereas grey-scale flow imaging allows the simultaneous imaging of blood flow and tissues. Compounding techniques improve the contrast resolution of tissues and reduce artefacts. If 3D techniques are now currently available, real-time 4D imaging has been recently introduced. Elastographic imaging is still under evaluation, but promising clinical results have been shown. Recent release of the DICOM specification has made the full integration of ultrasound to the PACS systems easier. All these advances indicate that the contribution and potential of ultrasound in patient management is still growing.

Equipment Design↗