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PubMed2002

Tailored reperfusion strategies in acute myocardial infarction: role of intravenous myocardial contrast echocardiography.

After many years of study and research, the noninvasive assessment of myocardial perfusion by echo contrast agents is becoming a clinical reality. The fast technological progress of echocardiographic imaging and the approval for human use in Europe and the United States of some first and second generation contrast agents explains the growing interest in this new methodology. Recently, a new second generation contrast agent, SonoVue, made of microbubbles stabilized by phospholipids and containing sulphur hexafluoride, has been introduced on the European market. We describe the role of intravenous myocardial contrast echocardiography with second-generation contrast agents such as SonoVue in the tailored reperfusion strategies in acute myocardial infarction.

Contrast Media↗

PubMed2002

A mathematical model for the flotation of waste activated sludge.

A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated.

Carbon Dioxide↗

PubMedDate not supplied

Breast lesion characterization with contrast-enhanced US. Work in progress.

PURPOSE: To characterise breast lesions on the basis of microcirculation features detected with contrast-enhanced US. MATERIALS AND METHODS: Thirty-six patients aged 42-63 years (mean age 55 years) with a single breast lesion previously detected at standard mammography were studied. All US examinations were performed using an ATL HDI 5000 ultrasound device with a 5-10 MHz linear-array transducer, before and after administration of ultrasound contrast medium Levovist (Schering(R), Berlin) was administered by bolus injection (2 ml/s) via a 20 G catheter probe. The mechanical index was set to high to obtain instant rupture of the microbubbles under insonation. Intensity/time curves of the transient scattering in the region of interest (ROI) after contrast administration were extrapolated. The areas under the ROI curves were also evaluated to quantitatively assess the scattering. RESULTS: The US baseline study and colour Doppler US identified 19 benign lesions (15 histologically proven) and 17 malignant lesions (16 histologically proven). The administration of contrast medium did not improve the specificity of the examination. Only by plotting the intensity/time curves of the regions of interest (ROI) and evaluating the areas under the ROI curves, was a significant correlation detected between US and histopathologic diagnosis. CONCLUSIONS: Although further evaluation on a larger series is needed, the analysis of breast lesions by contrast-enhanced perfusion US seems to be a promising technique. Perfusion US can usefully complement high-frequency US, especially when mammography is inconclusive.

Adult↗

PubMed2002

[A case of calvarial aneurysmal bone cyst: transcranial contrast sonographic examination with pulse inversion harmonic imaging method].

A 31-year-old female came to our hospital complaining of left frontal bulging with pain on 10 August 2000. The head x-p showed a radiolucent lesion and bulging at the same calvarial site. CT scan and MRI showed fluid-fluid levels, diploic cyst, deformity and hypertrophic calvarial change. There was a partial hypervascular part of cyst adjacent to the left frontal base by selective left external carotid angiography. Harmonic image is a contrast specific imaging modality that uses the nonlinear properties of contrast agents by transmitting at the fundamental frequency and receiving at multiples of these frequencies. Pulse inversion harmonic image(PIHI) using pulse inversion to eliminate and strengthen the harmonic frequency is more effective than conventional harmonic imaging. Transcranial sonographic examination showed hyper- and hypoechoic appearances in the cyst around abnormal hyperechoic appearances of the calvarial site. The transcranial contrast sonographic images with PIHI (hereinafter TCIpi) demonstrated an enhanced intracystic lower stratum and nearby the diploic part. That modality facilitates better visualization than the harmonic imaging method, enabling differentiation of vascular from avascular areas. As contrast agents are microbubbles, those are restricted in the vascular canal space. So TCIpi findings proved to be a blood circulation of the tumor, cyst and neighboring tissue. Enhanced areas changed by every minute and disappeared gradually. The findings were probably based on the vascular component of the tumor. We obtained images similar to those with CT and MRI. The patient underwent on 21 August. The tumor was removed along with the surrounding skull component. Fresh and old blood were mixed in the cyst. The clinical and pathological diagnosis was aneurysmal bone cyst. The postoperative course was uneventful and she was discharged on 29 August. Aneurysmal bone cyst is a rare calvarial tumor. An diagnostic finding is fluid-fluid levels that appear in approximately 30% of aneurysmal bone cysts. However, this is not a specific finding and has also been reported to occur in osteosarcoma, malignant fibrous histiocytoma, fibrous dysplasia, synovial sarcoma, hemangioma and simple bone cyst. Therefore, diagnosis of aneurysmal bone cyst is based on a combination of the various imaging applications, clinical and pathological findings. Gometz reported that sonographic examination was superior to any diagnostic imaging studies for aneurysmal bone cyst. Furthermore, the perfusion examination like TCIpi can directly observe blood circulation channels in tissue, so the specific enhancement changes of aneurysmal bone cyst could be observed. TCIpi is a useful method for diagnosis of aneurysmal bone cyst.

Adult↗

PubMed2003

Ultrasound in the management of breast disease.

Since its introduction in the 1960s, ultrasound (US) has never been more important in breast disease management as it is today. Its historical role as an adjunct modality to mammography in differentiating cystic from solid lesions has been widely expanded. US-guided sampling procedures represent widely accepted modalities in lesion evaluation. Preoperative localization under US guidance is one of the methods of choice for nonpalpable solid lesions. Screening breast US is currently being investigated and might prove useful for high-risk women and women with dense breasts. Continuous technologic advances, such as high-frequency transducers, new Doppler-based techniques, microbubble contrast agents, harmonic and compound imaging, three-dimensional US, elasticity imaging, US detection of microcalcifications, perfusion US imaging, and computer-aided diagnosis all carry promise of further increases in US utility in the diagnosis and detection of breast disease.

Breast↗

PubMed2003

Hepatopulmonary syndrome in a child.

We report a case of congenital biliary atresia and liver cirrhosis who developed hepatopulmonary syndrome thirteen years after Kasai operation. This 15-yea-old girl suffered from hyperbilirubinemia and acholic stool since birth. Congenital biliary atresia was diagnosed at 6 weeks of age and she received Kasai operation when liver cirrhosis was also found during the surgery. Dyspnea and cyanosis insidiously occurred since the age of 13 and she had been admitted to our hospital due to episodes of esophageal varices bleeding where esophageal varices ligation was performed. Serial examinations showed PaO2: 71 mmHg despite of 100% oxygen supplement. Pulmonary catheterization showed multiple arteriovenous shunts and macroaggregated albumin test revealed significant shunting. Contrast-enhanced echocardiogram showed microbubbles in the left heart. Thus, hepatopulmonary syndrome type II was diagnosed. Treatment is a dilemma although liver transplantation with concomitant lung transplantation is a possible choice.

Adolescent↗

PubMed2003

Value of echocardiography for observing left ventricular hypertrophy in the diagnosis of myocardial microvascular damage in hypertensives.

OBJECTIVE: To investigate the value of the echocardiographic observation of the left ventricular hypertrophy (LVH) in diagnosing myocardial microvascular damage in patients with essential hypertension (EH). METHODS: After intravenous injection with Quanfuxian (a contrast agent consisting of albumin and C3F8 prepared by Nanfang Hospital), the values of A (the maximum number of microbubbles accumulating in the local tissues for assessing the density of local microvessels), beta (the filling velocity of contrast agent for evaluating local blood flow velocity) and A x beta (the product of A and beta for estimating local myocardial blood flow) at rest and after dipyridamole injection were measured by intermittent harmonic imaging with myocardial contrast echocardiography (MCE). The ratios of A and beta along with the microvascular coronary flow velocity reserve (CFVR) were also calculated. RESULTS: Compared with the control group, the rest values of A, beta and A.beta in EH patients were higher, especially in those with LVH. After dipyridamole injection, the values of A, beta, A x beta and the ratios of A and beta, along with CFVR as well, were significantly lowered (P <0.01), and the reductions were especially obvious in LVH cases. As the hypertension exacerbated, the values of A and A x beta tended to increase in positive correlation with systolic and diastolic blood pressure (P <0.01), while the ratio of A and CFVR were decreased, the latter was inversely correlated with diastolic blood pressure (r=-0.55, P <0.01). Positive correlations were noted of the values of A and A x beta with the left ventricular mass and left ventricular mass index (P <0.01). CONCLUSION: EH patients, especially those with LVH, are characterized by increased rest myocardial microvascular blood flow, impaired myocardial microvascular flow reserve and endothelium independent vasodilation relaxing ability, and reduced capillary density, and these conditions tend exacerbate as the disease worsens. Microvascular function impairment should be suspected when complication of LVH arises in the EH patients. As a new important noninvasive technique, MCE can be a promising modality for diagnosing microvascular disease in essential hypertension.

Aged↗

PubMed2003

[Contrast echocardiography: from experimental validation to practice].

After a long wait, contrast echocardiography is at last becoming a reality. The experimental validation step has been passed with success and the first clinical results bring confirmation. The second generation contrast agents which are arriving on the market, and the spread of enhancement techniques such as Real-Time mode allow perfect visualisation of microbubbles within the left ventricular cavity, but equally at the level of the myocardial crown, thus targeting two direct applications in echocardiography: the first, indisputably, concerns the improvement in the detection of the endocardium in all the situations where it is insufficient, and in particular during stress echography; the second, more ambitious, confronts the study of myocardial perfusion, with a yet to be defined place in clinical practice.

Contrast Media↗

PubMed2003

Importance of jugular valve incompetence in contrast transcranial Doppler ultrasonography for the diagnosis of patent foramen ovale.

Transcranial Doppler (TCD) ultrasound with the intravenous injection of agitated saline as contrast (cTCD) is an effective method for detecting right-to-left intracardiac and extracardiac shunt (RLS); however, the sensitivity of cTCD in the diagnosis of RLS remains slightly less than that of transesophageal echocardiography, even in patients with adequate transtemporal ultrasonic bone windows. The authors present a case with cTCD underestimating RLS because of jugular valve incompetence in a 42-year-old man presenting with an episode of transient aphasia. Three weeks after transcatheter closure of a patent foramen ovale associated with an atrial septal aneurysm, he experienced 2 episodes of amaurosis fugax. Following a negative 45-minute embolus detection study with power M-mode TCD, the patient underwent a cTCD study with monitoring of the left middle cerebral artery (MCA), the anterior cerebral artery, and the submandibular extracranial internal carotid artery. A single microbubble (MB) was detected in the left MCA in only 1 of 5 studies; the remaining runs all failed to detect an RLS. Significant MB reflux was noted in the left internal jugular vein because of jugular valve incompetence. The authors conclude that incompetence of the jugular vein valve can result in a false negative cTCD study for RLS detection.

Adult↗

PubMed2002

[Ultrasound contrast agents in liver imaging].

Ultrasound contrast agents may modify any of the three basic physical interactions between ultrasound and body tissues: absorption, reflection and refraction, and then the amount of backscatter can be increased. New imaging techniques including second harmonic imaging, interval-delay harmonic imaging, pulse-inversion harmonic imaging and sub-harmonic imaging proved to increase the sensitivity of altrasound contrast agents. There are several types of agents that have been used for liver imaging: free gas bubbles, saccharide microparticle suspensions, encapsulated microbubbles, perfluorocarbons, organ or tumor-specific agents. Ultrasound contrast agents can show characteristic vascular features of liver, specific types of hepatic tumors, or characteristic dynamic phases of perfusion imaging; therefore they can provide meaningful information for clinical diagnosis.

Contrast Media↗

PubMed2003

Sentinel node detection using contrast-enhanced power Doppler ultrasound lymphography.

RATIONALE AND OBJECTIVES: To establish the feasibility of using contrast-enhanced interstitial ultrasound (US) lymphography as an alternative to current sentinel node detection methods. METHODS: Aqueous US contrast microbubble suspensions of varying diameter were evaluated in vitro to characterize response to insonation. Contrast media were then injected subcutaneously into the distal extremities of 11 normal dogs to target the cervical and popliteal lymph nodes (nodes, n = 40). First-order (sentinel) lymph nodes and second-order sublumbar nodes were imaged intermittently from 0 to at least 120 minutes following contrast injection using continuous power Doppler mode. Lymphoscintigraphy studies were performed on 4 dogs to verify lymphatic drainage patterns and sentinel lymph nodes. RESULTS: Contrast enhancement occurred in 34/40 (85%) sentinel nodes overall and in 30/32 (94%) nodes when submicron or near-micron diameter bubble formulations were used. In many instances, enhancement persisted throughout the imaging period. Contrast response was most pronounced using a high mechanical index and tissue artifact was reduced or eliminated when using a high pulse repetition frequency. CONCLUSIONS: Contrast-enhanced interstitial US lymphography could serve as an alternative to current sentinel node detection methods. Preliminary findings suggest that submicron or near-micron-diameter bubbles may be suitable for lymphatic imaging applications.

Animals↗

PubMed2003

[Value of US imaging of metacarpophalangeal joints in patients with early rheumatoid arthritis].

Technological advances in the field of ultrasound imaging may have, especially in metacarpophalangeal joints, an impact on decision making in patients with early rheumatoid arthritis. First, the normal anatomy of the metacarpophalangeal joints is briefly reviewed. Then, the authors describe the main ultrasound imaging findings of early RA. The role of ultrasound imaging in the assessment of therapeutic response as well as the benefit of microbubble ultrasound contrast agents are considered.

Arthritis, Rheumatoid↗

PubMed2003

Contrast M-mode power Doppler ultrasound in the detection of right-to-left shunts: utility of submandibular internal carotid artery recording.

Cardiac right-to-left shunts (RLSs) can be detected by echocardiography and transcranial Doppler ultrasound (TCD). In patients without adequate transtemporal bone windows, results may be obtained by insonating extracranial arteries; however, the sensitivity and practicality of this approach is unknown. In 34 patients evaluated with echocardiography for RLSs, 73 studies were performed with unilateral, simultaneous contrast TCD (cTCD) of the middle cerebral artery (MCA) and anterior cerebral artery (ACA) and submandibular power M-mode Doppler (PMD) ultrasound of the extracranial internal carotid artery (ecICA). The number of microbubble (MB) signals and their times of first appearance were determined. RLS volume was graded on 6 levels (I = trace, II = small, III = medium, IVa = large, IVb = shower, IVc = curtain) and compared between MCA and ecICA recordings. In 2 of 24 cTCD studies in 15 patients without evidence of RLSs on single-gated MCA monitoring, low-volume RLSs (grades I and II) were detected via ecICA insonation; in both, MB signatures were tracked in the ecICA, passing into the ipsilateral ACA. In 40 of 49 studies (26 patients) in which RLSs were demonstrated with single-gated MCA monitoring, more MBs were detected in the ecICA than the MCA, with either single-gated or M-mode images, with increases of 76.9% and 66.1%, respectively (P = .027). Compared to single-gated studies, M-mode technology detected nonsignificant increases in MB number in both the MCA and the ecICA (by 20.2% and 14.0%, respectively). Contrast PMD with cervical ICA recording is at least as sensitive and specific as the traditional MCA method in detecting RLSs; furthermore, this method seems to be more sensitive for low-volume RLSs (grades I-III) because of air MB decay (9.2%) and entry into the ipsilateral ACA (34.2%). This is in concordance with the increase of detected RLS grades observed in 32.7% of patients with echocardiography-documented RLSs. The authors therefore suggest the incorporation of ecICA PMD not only in patients with poor ultrasonic bone windows but also in every patient being evaluated for suspected RLSs.

Carotid Artery, Internal↗

PubMed2003

Sensitive noninvasive monitoring of tumor perfusion during antiangiogenic therapy by intermittent bolus-contrast power Doppler sonography.

Intermittent bolus-contrast power Doppler ultrasound was used for noninvasive, quantitative monitoring of tumor perfusion during antiangiogenic therapy. Subcutaneous heterotransplants of human squamous cell carcinoma cells in nude mice were treated with a blocking antibody to vascular endothelial growth factor receptor 2 (DC101) and repeatedly examined at weekly intervals. Using replenishment kinetics of microbubbles (Levovist) tumor vascularization, including capillary blood flow, was clearly visualized by this dynamic ultrasound method allowing the determination of a comprehensive functional status of tumor vascularization (blood volume, blood flow, perfusion, and mean blood velocity) in all examined tumors. DC101 treatment decreased tumor blood flow (-64%) and volume (-73%) compared with untreated controls (+409% and +185%, respectively). Regression of functional vessel parameters was observed early well before reduction of tumor size. The treatment-related amount of reduction in tumor volume was directly correlated for the initial tumor blood flow before start of therapy and the perfusion calculated at the preceding examination. The vessel density (immunofluorescence staining with CD31 antibody at different time points) showed an excellent correlation with the calculated relative blood volume (k = 0.84, P < 0.01), thereby validating intermittent sonography as a useful monitoring method. We conclude that intermittent sonography is a promising tool for comprehensive monitoring of antiangiogenic or proangiogenic therapies, especially during early stages of treatment, thus yielding information regarding a prospective evaluation of therapy effects beyond the follow up of tumor size.

Animals↗

PubMed2003

[Contrast-enhanced ultrasonography: renal applications].

Color Doppler US of the urinary tract is still facing a few limitations including, for B-mode imaging, the detection of small lesions, and, for color Doppler, the detection of low flow. Ultrasound contrast agents (USCA) improve these two limitations and allow the development of new functional applications for renal blood flow quantification. This improvement results from an increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequencing and signal processing that led to the concept of specific ultrasound sequences. Most of the clinical indications of contrast-enhanced ultrasonography remain to be validated with the improved detection of the non linear response. USCA improve the detection of abnormal micro and macrovascular disorders of the kidney, particularly for the detection and the characterization of renal artery stenosis, as well as for the visualization of renal infarction. This technique showed potentials for the study of renal masses, especially atypical cystic lesions. Among the remaining indications, the detection of reflux and testicular torsion are the most promising.

Adult↗

PubMed2003

[Contrast echocardiography: from experimental validation into practice].

Contrast echocardiography is at last becoming a reality. The experimental validation step has been completed with success and the first clinical results bring confirmation. The second generation contrast agents which are becoming available on the market, and the spread of enhancement techniques as Real-time mode allow perfect visualization of microbubbles within the left ventricular cavity, but equally at the level of the myocardial crown, thus targeting two direct applications in echocardiography: the first, indisputably, concerns improvement in the detection of the endocardium in all situations where it is insufficient, and in particular during stress echocardiography; second, more ambitious, is with regards to the study of myocardial perfusion with a potential role in clinical practice that remains to be determined.

Contrast Media↗

PubMed2004

[Conditions of contrast ultrasound that affect the proliferation of rat smooth muscle cells].

OBJECTIVE: To investigate the effect of an echo-contrast agent on the proliferation of rat smooth muscle cells under different ultrasound conditions. METHODS: The vascular smooth muscle cells of rats were cultured with echo-contrast agent in 96-well plates, followed by exposure to ultrasound of different conditions. Trypan blue staining was performed 48 h later, and the proliferation of the cells observed by MTT assay. RESULTS: No cytotoxicity was found by trypan blue staining when the mechanical index of ultrasound was below 0.75. Compared with the control cells, the proliferation of the smooth muscle cells was decreased following the exposure as the mechanical index of ultrasound increased. The most obvious inhibition of cell proliferation was resulted when the microbubble concentration was 20% for a 60-second exposure. CONCLUSIONS: The inhibition of the vascular smooth muscle cell proliferation by echo-contrast agent destruction is correlated with the mechanical index of the ultrasound, concentration of the echo-contrast agent, and exposure time of ultrasound.

Animals↗

PubMed2004

Paradoxical cerebral embolisation. An explanation for fat embolism syndrome.

Fat embolism occurs following fractures of a long bone or arthroplasty. We investigated whether paradoxical embolisation through a venous-to-arterial circulation shunt (v-a) could lead to cerebral embolisation during elective hip or knee arthroplasty. Transcranial Doppler ultrasound (TCD), following the intravenous injection of microbubble contrast, identified the presence of a shunt in 41 patients undergoing hip (n = 20) or knee (n = 21) arthroplasty. Intra-operative cerebral embolism was detected during continuous TCD monitoring. Of the 41 patients, 34 had a v-a shunt of whom 18 had an embolism and embolism only occurred in patients with a shunt (p = 0.012). Spontaneous and larger shunts were associated with a greater number of emboli (rs = 0.67 and rs = 0.71 respectively, p < 0.01). Observations in two patients with large spontaneous shunts revealed 368 and 203 emboli and unexplained post-operative confusion and pancreatitis. Paradoxical cerebral embolisation only occurred in patients with a shunt and may explain both postoperative confusion and fat embolism syndrome following surgery.

Adult↗