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PubMed1986

Intraoperative echocardiography for the evaluation of valvular regurgitation: experience in 263 patients.

Because of the limited orifice size and potential complications associated with prosthetic valves, native valve repair and reconstruction is an attractive surgical alternative. However, significant residual valvular regurgitation, which cannot be reliably detected intraoperatively by current methods, increases postoperative morbidity and mortality. Direct epicardial two-dimensional echocardiography with contrast injections can be applied intraoperatively to rapidly and accurately assess the presence and severity of valvular regurgitation in the baseline and postoperative state. Five milliliters of dextrose or saline are injected into the appropriate cardiac chamber, generating echogenic microbubbles (contrast) that normally exit in an antegrade direction, but reflux retrograde in the presence of valvular regurgitation. In a total of 263 patients who underwent intraoperative contrast echocardiography, 177 mitral, aortic, and tricuspid valves were adequately assessed by preoperative catheterization and results were compared with those of intraoperative contrast echocardiography. The sensitivity and specificity of the intraoperative detection of valvular regurgitation by echocardiography were 0.97 and 0.98, respectively, for all valves, 1.00 and 0.90 for mitral valves, and 0.91 and 1.00 for aortic valves. Moreover, intraoperative contrast echocardiography can also provide quantification of valvular regurgitation. In 120 mitral valves evaluated, the correlation between the degree of regurgitation determined by preoperative ventriculography and by intraoperative contrast echocardiography (both on a scale of 0 to 4+) was 0.93. Importantly, 11 patients who had mitral surgery (eight after mitral valve repair, and three after valve replacement) were identified as having significant postprocedure mitral regurgitation by intraoperative contrast echocardiography only, not by other methods. Additionally, nine patients were found to have significant tricuspid regurgitation by intraoperative contrast echocardiography after mitral surgery and underwent successful tricuspid annuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗

PubMed1985

[Left-right shunt caused by anomalous implantation of the left coronary artery in the trunk of pulmonary artery. Detection by contrast echocardiography].

The authors describe a case of an anomalous left coronary artery arising from the main pulmonary artery in an 11 year old child suffering from chest pain on effort and with a continuous murmur in the second left intercostal space. Two dimensional echocardiography (2D E) showed dilatations of the first segment of the right coronary artery and the anomalous origin of the left main coronary artery. A peripheral injection of microbubbles showed a left-to-right shunt between the left coronary artery and the pulmonary artery. Semi-quantitative evaluation of LV regional wall motion showed abnormal contraction of the anterolateral walls. Haemodynamic, angiographic data and the operative findings confirmed the diagnosis. The abnormal coronary ostium was closed and a bypass graft from the aorta to the left anterior descending artery was performed. Clinical and echocardiographic follow-up 7 months after surgery was completely normal.

Child↗

PubMed1985

[Severe hypoxemia due to a right-to-left shunt at the atrial level caused by an infarction of the right ventricle].

The authors report the case of a biventricular inferior myocardial infarction complicated in the acute phase by massive tricuspid regurgitation and a right-to-left interatrial shunt through a patent foramen ovale; this resulted in severe hypoxaemia. The diagnosis was made by contrast 2D echocardiography which showed ventriculo-atrial regurgitation and the passage of microbubbles from the right to the left atrium leading to opacification of the left ventricule: right heart catheterisation with oxymetry and selective right ventriculography confirmed the diagnosis. The hypoxaemia became less severe as the haemodynamic conditions improved. This is one possible mechanism of severe hypoxaemia in the acute phase of myocardial infarction and should be excluded routinely in this situation as it can have important prognostic and therapeutid implications.

Blood Gas Analysis↗

PubMed1985

Intraoperative contrast two-dimensional echocardiography. Evaluation of the presence and severity of aortic and mitral regurgitation during cardiac operations.

We have used contrast two-dimensional echocardiography in the intraoperative evaluation of aortic and mitral regurgitation in 35 patients undergoing cardiac operations. All of them underwent previous cardiac catheterization in order to document the presence and severity of regurgitation. With the pericardium open, a catheter was introduced into the left ventricle (to document mitral regurgitation) or into the ascending aorta (to document aortic regurgitation). The two-dimensional echocardiographic probe was placed on the anterior surface of the right ventricle to obtain a basal image, equivalent to a conventional parasternal longitudinal view. Dextrose in water (5 ml) was rapidly hand-injected through the catheter, while echocardiograms were recorded on videotape. The observation of contrast medium (microbubbles) flowing in the retrograde direction through the incompetent valve was carefully evaluated with the same scoring system used in the hemodynamic laboratory. In 34 cases there was agreement between angiographic and echocardiographic evaluation of the presence and severity of mitral and aortic regurgitation. Only one case was evaluated as mild aortic regurgitation by angiography and moderate aortic regurgitation by echocardiography. There were no false positives or false negatives in the study. In view of the high degree of correlation between contrast two-dimensional echocardiography and hemodynamic data, we suggest that our method is an important tool for the cardiac surgeon. In addition, the present approach overcame the disadvantages of the conventional intraoperative methods, most of which are performed in a nonbeating or fibrillating heart.

Adult↗

PubMed1985

[Spontaneous echocontrastography. Analysis of 50 cases, review of the literature and a proposal for its classification].

Spontaneous echocontrastographic effect (SEE) is sometimes detected in cardiac chambers. In order to propose a classification of the phenomenon we reviewed our series of 50 patients with SEE. We detected three type of SEE: type I, II, III. Type I was characterized by the presence of low amplitude echoes with slow and irregular motion in a cardiac chamber, in some cases the cloud of echoes had not defined borders (type IA), in other cases the cloud had well defined borders and was attached to a mural thrombus (type IB). Type II was characterized by the presence of echoes moving quickly across the mitral valve toward the left ventricle apex. Lastly, type III was characterized by the presence of microbubbles slowly and chaotically moving in right cardiac chambers. Type I SEE was detected only in patients with clinical conditions (mitral stenosis, congestive cardiomyopathies) characterized by slow intracardiac flow; type II was detected in 3 patients with mitral prosthesis, in 3 with constrictive pericarditis and 1 with severe aortic insufficiency. Lastly, type III was detected in 5 patients with tricuspid insufficiency.

Adolescent↗

PubMed1981

Contrast echocardiography of the inferior vena cava.

M-mode and two-dimensional subcostal contrast echocardiography were used in 67 patients and 10 normal subjects to evaluate the contrast echo effect on the inferior vena cava echogram in relation to the cardiac cycle and respiratory events. No contrast echoes were recorded in the inferior vena cava in normals during normal breathing. Contrast echoes were recorded entering the inferior vena cava in systole in 20 patients with tricuspid regurgitation and in pre-systole in patients with atrial septal defect and left-to-right shunt and in some of the patients with elevated right atrial and ventricular end-diastolic pressure. Forced inspiration increased the contrast echo effect and determined the penetration of microbubbles into the inferior vena cava. This latter feature occurred in all the patients and only in 1 normal subject. The entry of the contrast echoes into the inferior vena cava was attributed to the high right atrial ventricular end-diastolic pressure and to the reversed flow, from the right ventricle to the right atrium and inferior vena cava in tricuspid regurgitation and from the left atrium to the inferior vena cava in atrial septal defect. The contrast echocardiographic diagnosis of tricuspid regurgitation appeared to be most reliable. New encouraging results were obtained by this technique in diagnosing atrial septal defect and left-to-right shunt. The first appearance of the contrast, the time of appearance in relation to the cardiac cycle and the direction of the to and fro motion of contrast echoes were the most important factors considered for a correct diagnosis.

Cardiomegaly↗

PubMed1983

Gas phase formation and Doppler monitoring during decompression with elevated oxygen.

Subjects in 150 man-dives were precordially monitored with a 5-MHz Doppler ultrasound bubble detector. These measurements were made during a series of dives conducted to test decompression tables that utilize changes of breathing mixtures and a time-average PIO2 of 1.9 b during the entire decompression period. Precordially detected bubbles at depth were predictive for limb pain in divers approximately 50% of the time; however, 70% of the divers encountered bends problems in the absence of precordially detectable bubbles. Thus, while the presence of venous return bubbles can be associated with a risk factor for bends, the Doppler method appears to lack the specificity needed for personal dive monitoring. During the oxygen-breathing portions of the decompression individual bubbles could not be detected precordially. The amplitude of the Doppler-detected pulmonary artery flow sound increased, however, and possibly indicated the presence of numerous microbubbles.

Decompression↗

PubMed1983

[Diagnosis of tricuspid valve insufficiency based on clinical signs and contrast echocardiography].

The sensitivity and specificity of three clinical signs used for the diagnosis of tricuspid regurgitation (hepato-jugular reflux, congestion of the neck veins, inspiratory dilatation of the neck veins) were evaluated in 27 patients by contrast echocardiography. Tricuspid regurgitation was diagnosed when regurgitation of microbubbles into the inferior vena cava occurred at the time of the v-wave of the atrial pressure pulse. Nine of the 27 patients had tricuspid regurgitation (group I) and 18 patients (group II) did not. The end-diastolic diameter (group I: 3.1 cm; group II: 2.4 cm; p less than 0.05) and the end-systolic diameter (group I: 2.9 cm; group II: 2.3 cm; p less than 0.05) of the vena cava inferior were larger in the patients with tricuspid regurgitation than in those without. The end-diastolic short axis of the right ventricle (group I: 3.5 cm; group II: 3.2 cm; n.s.) did not differ significantly between the groups. Within group II, the echocardiographic dimensions of the vena cava inferior and the right ventricle did not differ in patients with congestion of the neck veins from those without. A significant correlation between clinical signs and tricuspid regurgitation could only be demonstrated for the hepato-jugular reflux (p less than 0.01, chi 2-test) and for inspiratory dilatation of the neck veins (p less than 0.05, chi 2-test).(ABSTRACT TRUNCATED AT 250 WORDS)

Dilatation, Pathologic↗

PubMed1982

Two-dimensional ultrasound and cardiac operations.

Two-dimensional ultrasound was employed for qualitative and quantitative studies during cardiac operations in 74 patients. A gas-sterilized phased-array transducer applied directly to the anterior surface of the heart produced high-quality images without a water path or other special manipulations. The techniques employed were successful in demonstrating alterations in cardiac anatomy associated with valve disease and cardiac tumors. Continuous clouds of microbubbles ejected from the left ventricle immediately following cardiopulmonary bypass were detected in 42% of 45 patients studied. Measurement of short-axis area change during systole proved useful for evaluation of intraoperative changes in left ventricular function. In the perioperative period, with the chest closed, the method detected increasing left ventricular mass during transplant rejection and was useful for monitoring changes in left ventricular performance when image quality was sufficient. The capabilities and limitations of this technique for special studies during cardiac operations should be familiar to surgeons with access to the method.

Cardiac Surgical Procedures↗

PubMed1994

[Early diagnosis of hepatocellular carcinoma].

Hepatocellular carcinoma (HCC) is considered to develop either on a background of preneoplastic lesions as multistep carcinogenesis or on a liver without such a lesion as de novo. The latter course can be assumed by our clinical experience of imaging diagnosis and by follow up studies of alpha fetoprotein (AFP) producing HCCs. Although serial checkup of AFP is important, serological or genetic approach is little use for early detection of HCC. At present, imaging diagnosis especially ultrasound is the best modality for detecting early developing HCC. The most reliable way for the final diagnosis of the detected mass is done by aspiration histology using a 21G needle with ultrasound guidance. Recent new imaging modalities such as contrast enhanced ultrasound using CO2 microbubbles or CTAP are not so reliable as aspiration histology, especially in tumors less than 15 mm in diameter.

Biomarkers, Tumor↗

PubMed1994

[Carbon dioxide as an intra-arterial contrast agent in echography: a technic for its preparation and the preliminary results in assessing hepatocarcinoma vascularization].

This paper reports on an original method to prepare a contrast agent consisting of CO2 microbubbles to be injected i.a. during ultrasound examinations (ultrasound angiography-USA), whose value was investigated in the study of tumor neovascularity in HCC patients. Thirty-five HCC patients underwent USA. CO2 was drawn out from a gas container under pressure and, through a sublimation process, made available in predetermined quantities in test tubes. USA was performed during angiography in 9 cases and immediately before arterial chemoembolization in the other 26 cases. In 51 lesions vascularity was evaluated with conventional angiography, USA and lipiodol CT. USA demonstrated lesion hypervascularity in 91% of cases, as confirmed by lipiodol CT (88%), versus 72.4% of angiography. In 3 of 35 patients USA demonstrated 6 more lesions undetected by other modalities: two of them were proved to be HCC and adenomatous hyperplasia at percutaneous biopsy. USA is a cost-effective procedure, which is easy to perform during conventional angiography: it is more sensitive than conventional angiography in the study of lesion neovascularity and can help plan lesion management, anticipating the results of chemoembolization. The role of USA in the diagnosis and treatment of HCC is, however, still to be defined.

Aged↗

PubMed1994

Survivorship models for estimating the risk of decompression sickness.

Several approaches have been used for modeling the incidence of decompression sickness (DCS) such as Hill's dose-response and logistic regression. Most of these methods do not include the time-to-onset information in the model. Survival analysis (failure time analysis) is appropriate when the time to onset of an event is of interest. The applicability of survival analysis for modeling the risk of DCS is illustrated by using data obtained from hypobaric chamber exposures simulating extravehicular activities (n = 426). Univariate analysis of incidence-free survival proportions were obtained for Doppler-detectable circulating microbubbles (CMB), symptoms of DCS and test aborts. A log-linear failure time regression model with 360-min half-time tissue ratio (TR) as covariate was constructed, and estimated probabilities for various TR values were calculated. Further regression analysis by including CMB status in this model showed significant improvement (p < 0.05) in the estimation of DCS over the previous model. Since DCS is dependent on the exposure pressure as well as the duration of exposure, we recommend the use of survival analysis for modeling the risk of DCS.

Computer Simulation↗

PubMed1994

Ultrasonographic angiography in gallbladder diseases.

Ultrasonographic (US) angiography was performed by sonographic examination with injection of carbon dioxide microbubbles through a catheter following conventional angiography in 41 patients with various gallbladder diseases. Three enhancement patterns were found; strong enhancement in the lesion from the periphery to the center was noted in patients with adenocarcinoma and benign polyp (type I), irregular partial enhancement at the margins of the lesion in those with adenosquamous carcinoma (type II), and internal regular enhancement in those with chronic cholecystitis, xanthogranulomatous cholecystitis and adenomyomatosis (type III). Pseudopolypoid lesion such as gallbladder debris showed no enhancement. US angiography may be useful in the differential diagnosis of gallbladder diseases, especially to differentiate the wall thickening type of gallbladder carcinoma from chronic cholecystitis or adenomyomatosis, and the pseudopolypoid lesion and fundal type of adenomyomatosis from benign polyp or polypoid-type carcinoma.

Adenocarcinoma↗

PubMed1994

[Integrated diagnosis of small hepatocellular carcinoma with imaging diagnosis].

Herein, we present the diagnostic efficacy of various imaging diagnostic techniques for small liver cancer(HCC) and HCC occurrence predictability by ultrasonography during the follow-up period of chronic liver diseases. During the recent 4 years, 78 nodules of small liver cancer measuring 2 cm or less in diameter were found in 50 patients with liver cirrhosis. In this study, the tumor size was divided into 2 groups; 1.5 cm or less in maximal diameter (group A) and 1.6 to 2 cm (group B). The tumor detectability of ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), angiography and lipiodol CT in group A vs group B was 96% vs 97%, 68% vs 88%, 65% vs 94%, 12% vs 78% and 38% vs 89%, respectively. Therefore, angiography and lipiodol CT were not effective for detection of small HCCs smaller than 1.5 cm. Recently, helical CT scanning has been induced in the diagnosis of HCCs and the tumor detectability was enhanced to 82% even in group A. Additionally, helical-dynamic CT has some advantages in evaluating vascularity, especially arterial feeding which is a specific finding to HCCs. In comparison with contrast-enhanced US using CO2-microbubbles, helical-dynamic CT had equivalent accuracy in diagnosing hypervascular tumors, while hypovascular masses were observed in about 30% of group A. With respect to prediction of HCC occurrence in cirrhotic liver, sonographic evaluation of liver parenchyma seemed to be an important parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

Physical and biochemical characterization of Albunex, a new ultrasound contrast agent consisting of air-filled albumin microspheres suspended in a solution of human albumin.

Albunex is a new ultrasound contrast agent for medical imaging. The product consists of air-filled albumin microspheres suspended in a solution of 5% (w/v) human albumin. The suspension is sterile, non-pyrogenic and isotonic, with a pH of 7.0 and a viscosity of 1.4 relative to water. The contrast effect is caused by the air-filled microspheres, which range in diameter from 1 to 15 microns, with less than 5% being larger than 10 microns. The product contains a total of about 7 x 10(8) microspheres/ml of suspension. The number concentration of microspheres with diameters between 4 and 10 microns is about 2 x 10(8)/ml. The latter microsphere fraction is assumed to give the main contribution to the ultrasound signal in the left ventricle of the heart after intravenous injection. The air-filled microspheres are prepared by sonication of a heated solution of 5% (w/v) human albumin. During the sonication process, microbubbles of air are formed which become encapsulated in a thin shell of aggregated albumin about 15 nm in thickness. Due to the stabilizing effect of the albumin shell, the air-filled microsphere suspension is stable for at least 2 years when stored refrigerated. The microsphere protein represents about 1.5% of the total protein in the suspension. The remaining protein is soluble albumin molecules which behave like the albumin molecules in the starting material when analysed by a number of biochemical techniques.

Albumins↗

PubMed1993

Avian myeloblastosis virus core-bound 7 S DNA, highly bent minute structures with sequence-directed curvature.

Structural properties and length distribution profile of 7 S avian myeloblastosis virus (AMV) DNA were studied by means of electron microscopy using two different techniques. This DNA represents mostly double strands, the single strands being in minority. We have shown directly that this DNA forms a bent structure typical of the majority of molecules. These bends are sensitive to the distamycin treatment which stretches most of the bent molecules. Some amount (up to 30%) of circular DNA molecules was detected also in DNA preparations, the nature and the size of which are reminiscent of electron microscopic data on microbubbles of replicating DNA. No specific AMV DNA structural features were found using osmium-tetroxide treatment. The basic size of AMV DNA was estimated to be approximately 150 bp, but its multimers were also detected. Their presence and significance is discussed.

Animals↗

PubMed1994

[Assessment of the distribution of renal cortical blood flow by contrast ultrasonography].

The importance of the distribution of intrarenal blood flow in the regulation of various renal functions, such as urine concentration and sodium excretion, has been well recognized. However, there have been no reliable methods to measure local flow in the kidney in vivo. The present study demonstrated the usefulness of contrast ultrasonography combined with injection of sonicated 5% albumin for assessment of the distribution of renal cortical blood flow in eleven mongrel dogs. The left kidney was displayed by tomographic echography, and microbubbles of sonicated albumin were injected into the abdominal aorta above the left renal artery. Video density time curves were generated and fitted to a time-intensity curve. Intrarenal infusion of acetylcholine (4.0 micrograms/kg/min) increased renal blood flow (RBF) from 2.5 +/- 0.3 to 4.6 +/- 1.0 ml/min/g kwt (p < 0.01), and norepinephrine (0.5 microgram/kg/min) decreased RBF from 2.5 +/- 0.3 to 1.2 +/- 0.5 ml/min/g kwt (p < 0.01). There were significant positive correlations between percent change in RBF and peak intensity and area under the curve, which were calculated with a time-intensity curve. Furthermore, the inner/outer renal cortex ratio of peak intensity significantly increased during acetylcholine infusion (0.72 +/- 0.11 vs 0.86 +/- 0.09; p < 0.01), whereas no significant change was observed during norepinephrine infusion. These results suggest that renal contrast ultrasonography may be useful for real-time assessment of the distribution of renal cortical blood flow in vivo.

Acetylcholine↗

PubMed1994

Saccharide-based contrast agents. Characteristics and diagnostic potential.

Since about 1980 tiny bubbles of gas ("microbubbles") have been known to be highly effective in ultrasonography because of enhancing backscatter ultrasound. After about 25 years of experimental work, the first industrial US contrast agent was approved by health authorities, the galactose microparticle SH U 454-Echovist, Schering AG, launched on the German market in 1991. Its major limitation is represented by the fact that it does not pass the pulmonary barrier and is confined to right heart abnormalities. Therefore another agent has been developed, the transpulmonary derivative of Echovist the galactose-based agent with the code number SH U 508 A (Levovist) which is in the late phase of clinical development for cardiac B-mode and Doppler blood pool US enhancement. A wide number of application areas can be foreseen for this contrast agent, which has been used for a multicenter trial. More than 1,200 patients were included in a European phase-III multicenter trial aimed at assessing the diagnostic efficacy and safety of SH U 508 A (Levovist). The patients included in the study had diagnostically insufficient Doppler signal intensity at routine Doppler or color Doppler vascular imaging. In more than 95% of the patients Doppler signal enhancement was achieved with at least one dose at the scheduled regimen, even in peripheral vessels. Enhanced Doppler US allowed a diagnosis to be made in many patients who would have otherwise undergone more invasive procedures. The diagnostic confidence, evaluated on a numerical rating scale (0-100) increased from 25.2 +/- 22.8% (prevalue) to 77.7 +/- 22.2% after Levovist (mean value +/- standard deviation, as calculated for a subgroup of 513 patients). Repeated i.v. injections were well tolerated. No specific risk was found for patients in any disease group.

Contrast Media↗