Use Of Ultrasound Contrast Media Research Articles

CEUS-guided PTA on stenotic AVF: Morphological and functional point of view.

Stenosis represents the main cause of hemodialysis fistula malfunction. The ultrasound-guided angioplasty with ecographic contrast (CEUS) could provide further advantages to the classical ultrasound guided method improving the morphological characterization of the stenosis and providing quantitative data with the creation of time intensity curves (TIC) collecting functional data comparable between pre and post procedure. A total of 10 CEUS-guided angioplasties were performed on malfunctioning fistulas. The sonographic contrast medium was injected into the vascular tree trough the introducer. Morphological and functional data nature were collected. Were generated TIC curves, obtained by positioning a ROI in correspondence with the post-stenotic tract of the efferent vein. The data collected, regarding the peak intensity reached by the signal (PI) and the time to reach the peak signal intensity (TTP), were compared in the pre and post-procedural phase with flow of vascular access (Qa) and resistance indices (RI). Statistically significant correlation (p < 0.05) was observed between Qa and TTP (r = 0.77; p = 0.009), RI and TTP (r = 0.71; p = 0.02), Qa and PI (r = 0.86; p = 0.0012), and between RI and PI (r = 0.88; p < 0.001). In addition to the advantages associated with the use of ultrasound contrast medium in improving the visualization and characterization of the stenosis by facilitating the PTA procedure, the functional data deriving from the quantitative analysis provide new parameters for evaluating the success of the procedure which could also be used as predictive markers of stenosis recurrence together with the classical ones.

Novel Technique of Non-Intravenous Use of Ultrasound Contrast Media for Biopsy Needle Visualization

Novel Technique of Non-Intravenous Use of Ultrasound Contrast Media for Biopsy Needle Visualization

Is CT still a method of monitoring patients after endovascular treatment of abdominal aortic aneurysms?

Introduction. The endovascular treatment of patient with abdominal aorta aneurysms has been a recognized alternative to classic surgery. One of the most common complications is an endoleak developing due to incomplete exclusion of the aneurysmal sac from circulation. Aim. To assess the value of ultrasound contrast agents for the diagnosis of endoleaks in patients with AAA treated by stent graft implantation. Material and methods. One hundred and ninety-eight patients with AAA were treated with stent graft implantation. Follow-up examinations, i.e. preand post-contrast ultrasound and angio-CT, were performed 6 months after treatment in all patients. In each ultrasound examination, colour, power, Bflow options were used before and after contrast injection; additionally, contrast-enhanced ultrasound (CEUS) was performed after contrast administration. Results. During the follow-up examinations after 6 months, pre-contrast ultrasound performed in all options (colour, power, Bflow) revealed 16 endoleaks: 6 type IA, 4 type IB, type 2 IIA and 4 type IIB; in post-contrast ultrasound using CEUS 22 endoleaks were confirmed and additionally 4 endoleaks were diagnosed: 2 type IIA, and 2 type IIB. In angio-CT, 22 endoleaks were diagnosed: 1 type IA, 5 type IB, 4 type IIA, and 7 type IIB. None of the four additional endoleaks observed with CEUS was found in angio-CT. Conclusions. The use of ultrasound contrast media significantly increases the sensitivity of ultrasound in the diagnosis of endoleaks, particularly type II ones. CEUS examinations show the greatest sensitivity in detecting endoleaks, as they disclose the endoleaks unrecognized by other techniques, including angio-CT. Post-contrast ultrasound can replace angio-CT in monitoring patients after stent graft implantations.

Measurement of pulmonary transit time in healthy cats by use of ultrasound contrast media “Sonovue®”: Feasibility, reproducibility, and values in 42 cats

ObjectiveTo evaluate the feasibility of measuring pulmonary transit time (PTT) in healthy cats by transthoracic echocardiography using the ultrasound contrast agent Sonovue®. To determine normalized PTT (nPTT) values in 42 healthy cats and to estimate the interobserver variability and the within-day repeatability of nPTT measurements. AnimalsForty-two privately owned healthy cats of different breeds, gender and age presented for cardiac examination. MethodsA bolus injection of contrast agent (Sonovue®) was administered intravenously. The right parasternal short axis echocardiographic view was used to record the contrast agent's transit time from the pulmonary artery to the left atrium. Pulmonary transit time and nPTT were determined independently by three examiners with different levels of experience. ResultsNormalized PTT was 4.12 ± 1.0 (mean ± SD) in our population. The median interobserver variability across our population was 6.8%, the median within-day variability for the three observers were 13.1%, 12.7% and 13%. No effect of the observer's experience on nPTT measurement was identified. Age, sex and body weight did not significantly influence nPTT. ConclusionsThis study demonstrates that nPTT measurement is feasible in cats using ultrasound and the blood pool contrast media Sonovue®. Measurements of nPTT can be performed in a clinical setting. Normalized PTT values in healthy cats are comparable with those reported in healthy dogs.

Ultrasound contrast media in paediatric patients: is it an off-label use? Regulatory requirements and radiologist’s liability

The use of ultrasound contrast media is yet to be validated in children. The rare reports in the scientific literature denote their "sporadic" and "experimental" use. Their most likely use is in the setting of off-label prescription of medications. As there are still no guidelines available in Italy for the off-label use of medications, we aim to define the duties, obligations and liability of ultrasound radiologists according to the laws in force.

Automated sonographic tubal patency evaluation with three‐dimensional coded contrast imaging (CCI) during hysterosalpingo‐contrast sonography (HyCoSy)

Evaluation of tubal status is one of the initial steps in the diagnostic work-up of infertile women. Hysterosalpingo- contrast sonography (HyCoSy), currently performed as part of the infertility work-up to assess tubal patency by transvaginal ultrasound (TVS) 1 , is based on the introduction of fluid into the uterine cavity and Fallopian tubes. To evaluate the Fallopian tubes, a sonographic enhancing positive-contrast medium may be used. Air, albumin with micro air bubbles, and galactose with micro air bubbles have been studied. These positive- contrast agents outline the course of the Fallopian tubes, producingahyperechoicappearance.Themostsimpleand inexpensive positive-contrast medium is saline solution mixed with air. When this solution is shaken, it generates as uspension of air bubbles that is easily identif ied sonographically when injected into the uterine cavity and Fallopian tubes 2-4 with spillage around the ovaries. However, while two-dimensional (2D) TVS HyCoSy with saline solution mixed with air appears to be an accurate and inexpensive screening tool to assess tubal patency, it is highly observer-dependent and is accurate only in the hands of experienced investigators 2-5 . In addition,

Contrast-enhanced Ultrasound in Obstetrics and Gynecology

Abstract Ultrasonography is a well-established imaging modality for evaluation of gynecologic tumors. In recent years, more sophisticated technologies like the use of intravascular contrast agents led to an improvement in the ability of the practitioner to differentiate benign from malignant masses. When we consider the safety of contrast-enhanced ultrasonography in obstetrics and gynecology, we must discuss about the effect of ultrasound contrast media on embryo and fetus. The use of ultrasound contrast media in pregnant women always concerns in the obstetricians because of the principle of not exposing a fetus to any drug. Therefore, the literature was reviewed for information about those safety and efficacy because of the uncertainty about the use of contrast media during pregnancy. Based on the limited information available, mutagenic and teratogenic effects have not been described after administration of ultrasound contrast media. No effect on the fetus has been seen after contrast media. The small potential risk associated with the nonthermal bioeffects via acoustic cavitation may be considered to prohibit the use in first trimester pregnant women. In previous studies including human trials, no evidence of adverse effect was reported. Contrast-enhanced ultrasonography could prove a useful adjunct in multiple gestations and in evaluation of uteroplacental circulation. It appears to be very promising potential in obstetrics.

Aktueller Stand der Sonographie in der Gastroenterologie - Leber und Milz

Conventional B-mode and colour duplex imaging is the first choice imaging technique after history taking and physical examination and for the interpretation of laboratory parameters. In the hands of a gastroenterologist ultrasound has become an equally important diagnostic tool as endoscopy. The constantly evolving technique with its possibility of higher resolution by use of "harmonic imaging" and signal enhancement with contrast medium is the reason for a practically relevant review of the situation. Practical references will be given for diagnostics of the liver and portal system including the spleen. The significance of the sonographic diagnosis of "fatty liver" is critically discussed. The overall importance of ultrasound to distinguish different aetiologies of diffuse liver diseases is relatively low. Nevertheless, it is a very sensitive means to detect complications of liver cirrhosis. Portosystemic shunts and typical changes in blood vessel morphology can be diagnosed by colour duplex sonography and used as indirect signs of advanced damage to liver parenchyma. In addition, ultrasound has its value in the confirmation or exclusion of dilated bile ducts as well as in the detection and differentiation of circumscribed liver lesions. The characterisation of focal liver lesions by ultrasound is sufficient in typical cases. The use of ultrasound contrast media (signal enhancers) raises the rate of differentiation and can avoid the uncritical and sequential application of radiological imaging (computed tomography [CT] or magnetic resonance imaging [MRI]). If in doubt about the nature of a lesion, a histological diagnosis remains indispensable. The examination of the spleen and its feeding vessels is regularly done in cases of diffuse parenchymal liver disease when searching for its complications, e. g., portal hypertension. Focal spleen lesions can be observed especially in the context of lymphoma (infiltration) and other bone marrow diseases. Through the application of contrast media, changes of vascularisation (e. g., infarcts) can be visualised and traumatic lesions can be diagnosed more precisely.

Sonographic Characterisation of Hepatocellular Carcinoma at Time of Diagnosis

Hepatocellular carcinoma (HCC) is a malignant liver tumour with a high prevalence world-wide. For screening procedures conventional transabdominal B-mode ultrasound and AFP determination are commonly used. We investigated 100 consecutive patients with histologically proven hepatocellular carcinoma in order to evaluate sonographic characteristics in unselected patients and to compare native and contrast-enhanced ultrasonographic techniques. We investigated 100 consecutive patients with hepatocellular carcinoma at time of diagnosis with respect to echogenicity, patterns of vascularity, and portal/hepatic vein thrombosis. In addition to B-mode and native power Doppler sonography, contrast-enhanced power Doppler sonography with SHU 508A was used in 65 patients. The ultrasound appearance with conventional B-mode of hepatocellular carcinoma was hypoechoic in 48 % of the cases, isoechoic in 9 %, hyperechoic in 19 %, and in 25 % a mixture between hyper- and hypoechoic appearance was found compared to the surrounding liver tissue. Contrast-enhanced power Doppler sonography with SHU 508A changed the pattern of tumour vascularity in 27 % of patients into hypervascular, mainly in small lesions. At the time of diagnosis, the most commonly observed finding in hepatocellular carcinoma is that they appear hypervascular, independent of their size. The use of ultrasound contrast media should be considered to achieve characterisation of liver nodules in cirrhotic livers because they can improve the evaluation of tumour vascularity. Hypovascular HCC are found in about 10 % even after the administration of a contrast agent.

Detection of endoleak with enhanced ultrasound imaging: comparison with biphasic computed tomography.

To compare unenhanced and enhanced ultrasound imaging to biphasic computed tomography (CT) in the detection of endoleak after endovascular abdominal aortic aneurysm (AAA) repair. Fifty-three patients (44 men; mean age 70 years) were examined during 96 follow-up visits after endovascular AAA repair. All patients had color Doppler and power Doppler ultrasound studies performed before and after the administration of an ultrasound contrast agent. Biphasic (arterial and delayed) CT was performed on the same day, and the ultrasound and CT studies were independently scored to record the presence or absence of endoleak and the level of confidence in the observation. The sensitivity of the ultrasound techniques to detect endoleak improved with the use of ultrasound contrast media, ranging from a low of 12% with unenhanced color Doppler to 50% with enhanced power Doppler. However, the enhanced power Doppler failed to detect 9 type II endoleaks identified by CT (86% negative predictive value for endoleak). There were only 2 graft-related endoleaks in the study; one was diagnosed from the ultrasound image, but the other had nondiagnostic ultrasound scans because of poor views. Ultrasound scanning with or without contrast enhancement was not as reliable as CT in diagnosing type II endoleak. CT imaging remains our surveillance modality of choice.

Contrast-enhanced ultrasound improves hepatic vessel visualization after orthotopic liver transplantation.

We investigated whether color-coded Doppler sonography combined with an ultrasound contrast medium would improve the assessment of liver-supplying vessels after orthotopic liver transplantation. Forty-seven patients after orthotopic liver transplantation participated. Examinations were done without and then with the ultrasound contrast medium Levovist. Visualization of the liver-supplying vessels was assessed with a scoring system. Visualization of the portal vein was similar without and with contrast medium. Hepatic arteries were visualized in 39 patients without contrast medium and 46 patients with contrast medium. The remaining patient showed hepatic artery thrombosis, which was confirmed angiographically. With the use of Levovist, the examination took 3.7 min rather than the usual 6.4 min. Imaging of hepatic arteries after liver transplantation improved significantly with the use of ultrasound contrast medium. These findings are important because the early detection of blood flow through the liver after transplantation affects prognosis.

Clinical applications of colour Doppler energy imaging in the female reproductive tract and pregnancy.

This review describes the usefulness of colour Doppler energy (CDE) (or power Doppler) imaging to measure vascularization in the female reproductive tract. CDE imaging is characterized by an increased sensitivity to flow, and thus may be useful in low-flow states and when optimal Doppler angles cannot be obtained. In addition, longer segments of vessels and more individual vessels can be visualized with CDE imaging. The role of CDE imaging in the evaluation of stromal vasculature in normal and in polycystic ovaries is described, and the relationship between follicular vascularity and outcome following in-vitro fertilization are discussed, together with the findings obtained from the evaluation of thecal arteriole of corpus luteum in early pregnancy. The fundamental role of CDE imaging in differentiation among ovarian masses is also reviewed. We summarize the role of CDE imaging in pregnancy, and describe two new applications of three-dimensional power Doppler sonography and the use of ultrasound contrast media. In conclusion, CDE imaging can replace conventional colour Doppler when the information on the direction of flow is not useful. Moreover, the technique appears superior to others for describing microvascular architecture and determining the presence or absence of flow.

Vascularization of breast tumors: use of ultrasound contrast medium in evaluating tumor entity. Preliminary results

The objectives of the present study were to investigate the utility of an ultrasound echo enhancer in the evaluation of the dignity of breast tumors and to identify the best examination parameters. 68 breast tumors in 61 female patients who were referred for operative tumor removal were examined by color-coded duplex sonography before and after administration of Levovist. The investigated parameters were: a) the degree of enhancement, b) the number of tumor vessels, c) the time to maximum enhancement, and d) the morphological pattern and course of vessels. With regard to parameters A, B, and C there were in part pronounced overlaps between malignant (n = 44) and benign (n = 24) lesions. The best differentiation was found for parameter D with a sensitivity of 95% and a specificity of 83%. In all previously operated patients a distinction between a postoperative scar (n = 8) and a tumor recurrence (n = 13) was possible. The use of Levovist leads to a clear improvement in the evaluation of dignity by duplex sonography. On the basis of our preliminary results, the characteristic pattern of vascular morphology and course is the best examination parameter. In particular, the otherwise difficult distinction between scar and recurrence appears to be an interesting application.

IMPROVING COLOR DOPPLER EVALUATION OF KIDNEY TRANSPLANTATION WITH A NEW ULTRASOUND CONTRAST MEDIUM

567 Color doppler ultrasound (CDUS) is routinely performed after kidney transplantation to dissect intraparencymal blood flow variations which can mirror post-transplant complications such as vascular thrombosis or stenosis. The bias of the method is a reduced capability in depicting the outer renal cortex flow where interlobular vessels are located. This accounts for a low reliability in the differentiation of pathological conditions where flow changes are minimal such as acute tubular necrosis (ATN), rejection (RJ) and cyclosporine toxicity. Recently, an ultrasound contrast medium (UCM) consisting of air-filled shell-stabilized microballons have been proposed for the study of several vascular disorders. In normal kidneys, contrast enhancement of the doppler images allows an optimal study of flow characteristics up to the interlobular vessels. This experience reports a preliminary pilot study with the use of UCM in 10 consecutive kidney transplants performed in our center from November 26 to December 17, 1997. All cases were first cadaveric renal transplant under cyclosporine-based immunosuppression. All patients were evaluated blindly by two operators. The CDUS was performed on pod#5 by Aloka SD-2000 with 5 and 7.5 Mhz probes before and after 6.5 ml. i.v. bolus (400 mg/ml) of a galactose-based contrast agent(Levovist®, Shering; Berlin, Germany). On the renal cortex, the following parameters were calculated (5 determinations for each parameter): resistive index (RI), pulsatility index (PI) interlobular flow (IL) and main renal artery flow (RA). 4 out of 10 patients experienced ATN with a delayed recovery of the graft function, 1 patient developed an acute rejection episode within the first postoperative week, while the remaining patients had a favorable post operative course. A significant spectral Doppler enhancement was observed after the contrast administration enabling the pulse doppler sampling in the outer cortex of all the patients. Impaired outer cortical flow was detected in 5/10 patient (4 ATN, 1 RJ) with a PI = 1,81 ± 0.06 and a RI = 0.86 ± 0.06 compared to a PI = 1.23 ± 0.2 and RI = 0.74 ± 0.05 reported in normal kidney transplants (Student's test: pPI = 0.004; pRI = 0.01, respectively). A rearrangement of the cortical perfusion in patients with an abnormal clinical course was also documented by a significant increase of the interlobular flow due to the important peripheral engorgement: IL = 0.68 ± 0.32 ml/min vs. IL = 0.42 ± 0.17 in uneventful transplant (p = 0.01). RA was comparable between the two groups of patients ranging between 540 - 860 ml/min. Furthermore, no significant side effects or changes in patients hemodynamics were recorded upon contrast administration. In conclusion, the use of UCA in kidney transplantation allows a non-invasive study of the outer cortical flow. At this level, the accuracy of flow resistance measurements grants a significant correlation between doppler images and the clinical course of the transplanted kidney and provides a useful tool for monitoring the kidney transplantation outcome in the early postoperative period.

Usefulness of ultrasound contrast medium in perineal sonography for visualization of bladder neck funneling—first observations

Objectives To assess the efficacy of ultrasound contrast medium when imaging bladder neck anatomy with perineal ultrasound. Methods In 10 female patients with urinary stress or stress-urge incontinence, a new echogenic contrast medium (Echovist) was intravesically administered and perineal ultrasound performed. The examination was done with the women in the upright position both without and with ultrasound contrast medium at rest and during pressing, and the pictures of the bladder base, bladder neck, and urethra were compared. Results With the patient in the upright position, the ultrasound contrast medium enters the urethra during pressing and bladder neck funneling is identified more accurately than without contrast medium. With Echovist, bladder neck funneling was detected in 9 of the 10 cases but without it in only 4 cases. Conclusions The use of ultrasound contrast medium results in a better visualization of the bladder neck anatomy. Bladder neck funneling and urinary leakage are seen more distinctly, and this improves the diagnostic reliability in female urinary stress incontinence. This pilot study supports the necessity for further investigations in the use of ultrasound contrast medium as a diagnostic improvement of perineal ultrasound.

Improvement of perineal sonographic bladder neck imaging with ultrasound contrast medium

To assess the efficacy of ultrasound contrast medium when imaging bladder neck anatomy in perineal ultrasound. In 39 women with clinically and urodynamically proven urinary stress or stress-urge incontinence, a new echogenic contrast medium (Echovist) was administered transurethrally and perineal ultrasound was performed. Women were examined in the upright position both without and with ultrasound contrast medium at rest and during Valsalva maneuver, and the pictures of the bladder base, bladder neck, and urethra were compared. With the subject in the upright position, the contrast medium lay at the lowest point of the bladder and resulted in a reverse picture of the bladder base and bladder neck and clear visualization of these structures. In women with urinary stress incontinence, the ultrasound contrast medium entered the urethra during Valsalva, and bladder neck funneling was identified more accurately than without contrast medium. With Echovist, bladder neck funneling was detected in 38 of the 39 cases, compared with only 19 when it was not used. Furthermore, when the bladder neck, urethra, or bladder base were not visible with plain perineal ultrasound, they were seen when ultrasound contrast medium was used. The contrast agent was well tolerated, and there were no adverse side effects. The use of ultrasound contrast medium improves visualization of the bladder neck anatomy. Bladder neck funneling and urinary leakage are seen more distinctly, and this improves the diagnostic reliability in female urinary stress incontinence.