Three-dimensional fetal echocardiography: gated versus nongated techniques

The purpose of this study was to compare gated with nongated three-dimensional fetal echocardiography in terms of the ability to demonstrate fetal cardiac anatomy. We examined nine fetuses in utero using conventional two-dimensional sonographic imaging equipment, an electromagnetic position sensor, and a computer-graphics workstation. Free-hand sweeps were performed through the fetal heart and great vessels in either transverse or sagittal orientations with respect to the fetal heart. Seven transverse and five sagittal sweeps were selected for reconstruction and analysis. Cardiac gating was performed by using a temporal Fourier transform to determine the fundamental frequency of cardiac motion. Two-dimensional data from each sweep were reprojected to a series of volume data sets. Each series was then condensed to a single volume, so that each two-dimensional sweep could be compared with its respective gated and nongated volume data sets. The two-dimensional data were reviewed utilizing a display with forward and backward cineloop capability. The gated and nongated volume data sets were displayed interactively as a series of three orthogonal planes, with the ability of the observer to control the location of each image plane within the volume. The gated data were animated with variable display frame rates. Conventional two-dimensional imaging provided a fairly complete evaluation of the fetal heart when scanning included the four-chamber view with a sweep across the outflow tracts. Nongated three-dimensional fetal echocardiography allowed visualization of some structures and views not demonstrated with two-dimensional ultrasonography. Gated three-dimensional fetal echocardiography provided significantly better visualization and comprehension of cardiac anatomy than nongated three-dimensional fetal echocardiography. The superiority of gated over nongated three-dimensional fetal echocardiography appears to come from both improved image quality and the anatomic clues that derive from the ability to view cardiac motion.     

Cor triatriatum in a 70-year-old woman: role of transesophageal echocardiography and dynamic three-dimensional echocardiography in diagnostic assessment

In this report we describe a 70-year-old woman with unrecognized nonobstructive cor triatriatum (CT). She had concomitant mitral regurgitation and coronary artery disease. Diagnosis of CT and its hemodynamic assessment were accomplished by transesophageal echocardiography. Dynamic three-dimensional echocardiography demonstrated multiple fenestrations in the left atrial membrane. Intraoperative findings confirmed the diagnostic accuracy of three-dimensional echocardiography. To our knowledge, this is the first case of CT that has anatomic correlation with three-dimensional echocardiography.     

Three-dimensional echocardiographic measurement of right ventricular volume in children with congenital heart disease validated by magnetic resonance imaging

Measurement of right ventricular volume and function by two-dimensional echocardiography is unreliable because of the asymmetric shape of the right ventricle. The purpose of this study was to validate the accuracy of transthoracic three-dimensional echocardiography in assessing right ventricular volumes in children with congenital heart disease after surgical repair of the defects, by comparison with those measured by magnetic resonance imaging. We examined 13 children after repair of tetralogy of Fallot (10), hypoplastic left heart syndrome (2), or atrial septal defect (1). Each underwent magnetic resonance imaging followed by three-dimensional echocardiography done with a transthoracic 5 MHz, prototype internally rotating omniplane transducer. In both methods, endocardial borders were manually traced and volumetric slices were summated. Close correlation was observed between the two methods (R2 0.91 for end-systolic volumes, 0.90 for end-diastolic volumes, 0.64 for ejection fraction, and 0.92 for interobserver variability). A limits-of-agreement analysis showed no adverse trend between the two methods under values of 100 ml and low variation around the mean values. We conclude that three-dimensional echocardiography measurement of right ventricular volumes correlates closely with magnetic resonance imaging in children with operated congenital heart disease and may allow accurate serial evaluation in these patients.     

Virtual and three-dimensional bronchoscopy with spiral and electron beam computed tomography

PURPOSE: To compare spiral computed tomography (CT) and electron-beam CT (EBT) for 3D and virtual CT-bronchoscopy. MATERIALS AND METHODS: 17 patients with various disorders of the tracheobronchial system were examined using fiberoptic bronchoscopy, spiral CT and EBT. 3D images were reconstructed from CT data sets using automated segmentation based on volume-growing methods. Surface-rendered, volume-rendered, and hybrid reconstructions were visualized in real time using a data helmet. RESULTS: All data sets could be processed to high-quality three-dimensional (3D) and virtual reconstructions. The reduction of motion artifacts due to shorter scan times made EBT data sets better suited for automated segmentation and less susceptible to motion artifacts. 3D and virtual reconstructions did not increase the diagnostic sensitivity of CT compared to axial reconstructions alone. CONCLUSIONS: Shorter scan times of CT imaging yield higher-quality 3D and virtual reconstructions. Modern reconstruction techniques are valuable visualization tools for select indications and are the prerequisite for future developments in computer-aided medicine.     

99mTc-HL91. Effects of low flow and hypoxia on a new ischemia-avid myocardial imaging agent

OBJECTIVES: The aim of this study was to determine whether three-dimensional (3D) myocardial contrast echocardiography (MCE) could provide an accurate in vivo assessment of risk and infarct volumes. BACKGROUND: MCE has been shown to accurately define risk area and infarct size in single tomographic slices. The ability of this technique to measure risk and infarct volumes by using three-dimensional echocardiography (3DE) has not been determined. METHODS: Fifteen open chest dogs underwent variable durations of coronary artery occlusion followed by reperfusion. At each stage, MCE was performed by using left atrial injection of AIP201, a deposit microbubble with a mean diameter of 10 +/- 4 microm and a mean concentration of 1.5 x 10(7) x ml(-1). Images were obtained over a 180 degree arc with use of an automated rotational device and were stored in computer as a 3D data set. Postmortem risk area and infarct size were measured in six to eight left ventricular short-axis slices of equal thickness using technetium-99m autoradiography and tissue staining, respectively. MCE images corresponding to these planes were reconstructed off-line. RESULTS: A close linear relation was noted between the volume of myocardium not showing contrast enhancement on 3D MCE during coronary occlusion and postmortem risk volume (y = 1.2x - 3.0, r = 0.83, SEE = 5.1, n = 15). The volume of myocardium not showing contrast enhancement on 3D MCE after reperfusion also closely correlated with postmortem infarct volume (y = 1.1x - 3.9, r = 0.88, SEE = 4.8, n = 11). No changes in systemic hemodynamic variables were noted with injections of AIP201. CONCLUSIONS: When combined with AIP201, a deposit microbubble, 3D MCE can be used to accurately determine both risk and infarct volumes in vivo. This method could be used to assess the effects of interventions that attempt to alter the infarct/risk volume ratio.     

Recent trends in drug delivery systems: liposomal drug delivery system--preparation and characterisation

The strong relation between increased left ventricular mass and cardiovascular events makes accurate measurement of left ventricular mass a high priority, especially in patients with hypertension. M-mode echocardiography is used most widely to measure left ventricular mass because of its wide availability, moderate expense, anatomic and prognostic validation and lack of radiation or claustrophobia; however, this technique is expertise-dependent and may give erroneous results in distorted ventricles. Two-dimensional and especially three-dimensional echocardiography increase the precision with which left ventricular mass is measured but they are more time-consuming and difficult to perform on a large scale. Magnetic resonance imaging provides highly accurate left ventricular mass measurements and permits tissue imaging but its use is limited by expensive, fixed facilities and claustrophobia. Cine computed X-ray tomography also measures left ventricular mass accurately and permits perfusion assessment with contrast injection but it involves radiation and the use of fixed facilities of limited availability. Understanding the strengths and limitations of available techniques can facilitate selection of the most appropriate method to measure left ventricular mass in a particular setting.     

Hypercholesterolemia enhances oxidant production in mesenteric venules exposed to Ischemia/Reperfusion

BACKGROUND: Three-dimensional echocardiography allows calculation of left ventricular ejection fraction without geometric assumption on the ventricular shape. Our aim was to validate this technique in a paediatric population with distorted ventricles. METHODS: Twenty-one patients aged 6 months to 17 years underwent equilibrium radionuclide angiography and three-dimensional echocardiography. Fourteen patients had dilated cardiomyopathy and seven had univentricular hearts. A new, easy to handle, transthoracic rotational probe was used and motion artefacts were limited during the rotation (3 degrees intervals with ECG and respiratory gating). Left ventricular volumes and ejection fraction were calculated using the Simpson's rule with 12 slices. RESULTS: Three-dimensional echocardiography correlated well with equilibrium radionuclide angiography for ejection fraction measurement (r = 0.90; the mean difference between the two methods being 3.8 +/- 6%). Intra-observer and inter-observer variabilities for 3D echocardiography were 2.4% and 4.5%. CONCLUSIONS: Three-dimensional echocardiography is an accurate, non-invasive, and reproducible methods to measure left ventricular ejection fraction in children.     

Three-dimensional versus two-dimensional video system for the trained endoscopic surgeon and the beginner

Because of the lack of depth perception in current two-dimensional endoscopic video systems, the performance of fine motor movements is impaired. Endoscopic surgeons are generally able to cope with this limitation, and the performance of complex procedures becomes easy with experience. To assess the value of three-dimensional vision, two groups of surgeons, with and without experience in endoscopic surgery, underwent dexterity tests at a simulator. Data from use of two- and three-dimensional video systems were analysed and are discussed in this paper. The three-dimensional system improved the ability to perform endoscopic procedures, particularly when the highest degree of hand-eye coordination was needed. A common sensation of ocular fatigue, related to the prolonged use of this equipment, may limit its usefulness in advanced endoscopic procedures.     

Three-dimensional transesophageal echocardiographic assessment for prosthetic valves

We evaluated three-dimensional transesophageal echocardiographic assessment of the implanted mechanical valves by rotational scanning method. Patients were 7 mitral valve replacement and one aortic valve replacement, 2 mitral and aortic valve replacement. In 2 cases of 7 mitral valve replacement, the prosthetic valve regurgitation was evaluated using by color Doppler echocardiography. In this study, multiplane transesophageal probe was used. It rotated at 2-degree intervals from 0 to 180 degrees and the three-dimensional reconstruction was performed by echo scan workstation system (TOMTEC Inc, Munich, Germany). In mitral valve replacement cases, the valve motion of bileaflet valve (St. Jude Medical valve and ATS valve) were showed very clearly. The struts was easily recognized in the St. Jude Medical valve (SJM valve) cases. In one of SJM valve cases, the pannus formation was revealed, but it did not disturb valve motion. The prosthetic valve regurgitation can be seen accurately. However, aortic valve and ball valve cases cannot be reconstructed because of artifact from prosthetic valve and ultrasonic direction. The prosthetic valve regurgitation, pannus formation which was difficult to be showed in two-dimensional echocardiography and relationship between annulus and sewing cuff can be evaluated by this three-dimensional echocardiography. In this study, this system has some problems, for example real-time evaluation is impossible, aortic valve and ball valve cases cannot be reconstructed. However, we think that this new technology is suitable for evaluating valve thrombus, valve dysfunction and paravalvular leakage. In conclusion, the three-dimensional echo-cardiography demonstrated, reliable and accurate examination, and it can evaluate various complications of prosthetic valve.     

Efficacy of cobalt chelates in the rabbit eye model for epithelial herpetic keratitis

STUDY OBJECTIVE: Accurate diagnosis in emergency department patients with possible myocardial ischemia is problematic. Two-dimensional echocardiography has a high sensitivity for identifying patients with myocardial infarction (MI); however, few studies have investigated its diagnostic ability when used acutely in ED patients with possible myocardial ischemia. Therefore we investigated the ability of ED echocardiography for predicting cardiac events in patients with possible myocardial ischemia. METHODS: Echocardiography was performed within 4 hours of ED presentation in 260 patients with possible myocardial ischemia, and was considered positive if there were segmental wall motion abnormalities or the ejection fraction was less than 40%. ECGs were considered abnormal if there was an ST-segment elevation or depression of greater than or equal to 1 mm, or ischemic T-wave inversion. Cardiac events included MI and revascularization. RESULTS: Of the 260 patients studied, 45 had cardiac events (23 MI, 19 percutaneous transluminal angioplasty, 3 coronary bypass surgery). The sensitivity of echocardiography for predicting cardiac events was 91% (95% confidence interval 79% to 97%]), which was significantly higher than the ECG (40% [95% CI 27% to 55%]: P < .0001), although specificity was lower (75% [95% CI 69% to 81%] versus 94% [95% CI 90% to 97%]; P < .001). Addition of the echocardiography results to baseline clinical variables and the ECG added significant incremental diagnostic value (P < .001). With use of multivariate analysis, only male gender (P < .03, odds ratio [OR] 2.4 [1.1 to 5.3]), and a positive echocardiographic finding (P < .0001, OR 24 [9 to 65]) predicted cardiac events. Excluding patients with abnormal ECGs (N = 30) did not affect sensitivity (85%) or specificity (74%) of echocardiography. CONCLUSION: Echocardiography performed in ED patients with possible myocardial ischemia identifies those who will have cardiac events, is more sensitive than the ECG, and has significant incremental value when added to baseline clinical variables and the ECG.     

Three-dimensional echocardiography. Principles and applications

Three-dimensional echocardiography is based on two methods of retrospective reconstruction from two-dimensional echocardiographic images. The acquisition of the two-dimensional images may be free or imposed, the transducer either carrying an emission-reception system or fixed to an articulated support providing data about its position. In the first system, manual tracing of the contours of the region of interest performed on each frame are superimposed after time sequencing (using the ECG) and spatial repositioning, so enabling three-dimensional visualisation of the contours of the cardiac structures: this approach provides reliable quantitative information (volumes, mass and ejection fractions) and has led to the redefinition of the echocardiographic criteria of mitral valve prolapse. The second system is based on equidistant sections obtained by progressive, controlled two-dimensional scanning (parallel, arc of a circle and rotational) of the structure of interest: a value of grey scale is assigned to the space between two adjacent pixels, enabling the formation of voxels which, when superimposed, give the required effects of volume and surface for three-dimensional imaging. It is then possible to obtain any section of the volume and simulate surgical views of the beating heart. This approach may significantly improve diagnostic accuracy compared with two-dimensional echocardiography and provides access to new quantitative and qualitative parameters.     

Potential advantage of flash echocardiography for digital subtraction of B-mode images acquired during myocardial contrast echocardiography

Optimal assessment of myocardial perfusion with contrast echocardiography by using B-mode imaging often requires image alignment and background subtraction, which are time consuming and need extensive expertise. Flash echocardiography is a new technique in which primary images are gated to the electrocardiogram and secondary images are obtained by transmitting ultrasound pulses in rapid succession after each primary image. Myocardial opacification is seen in the primary image and not in the secondary images because of ultrasound-induced bubble destruction. Because the interval between the primary and first few secondary images is very short, cardiac motion between these images should be minimal. Therefore we hypothesized that 1 or more secondary images could be subtracted from the primary image without the need for image alignment. The ability of ultrasound to destroy microbubbles was assessed by varying the sampling rate, line density, and mechanical index in 6 open-chest dogs. The degree of translation between images was quantified in the x and y directions with the use of computer cross-correlation. At sampling rates of 158 Hz or less and a mechanical index of more than 0.6, videointensity rapidly declined to baseline levels by 25 ms. Significant translation between images was noted only at intervals of more than 112 ms. It is concluded that flash echocardiography can be used for digital subtraction of baseline from contrast-enhanced B-mode images without image alignment. Background subtraction is therefore feasible on-line, potentially eliminating the need for off-line image processing in the future.     

Effect of flecainide on heart rate variability in subjects without coronary artery disease or congestive heart failure

Echocardiography has a role in the management of acute complications of penetrating cardiac trauma. We report the case of a 30-year-old man who sustained a stab wound to the chest. In this case a traumatic perforation of the ventricular septum and the anterior leaflet of the mitral valve caused by a knife occurred without pericardial effusion. The diagnosis was made by transthoracic echocardiography. The ability of transesophageal echocardiography to delineate the intracardiac injuries more precisely helped to guide the surgical procedure.     

The role of echocardiography in preoperative diagnosis of cardiac risk in patients before non-cardiac surgical interventions

Echocardiography is a noninvasive method for cardiac evaluation. A review of the current literature shows that the routine use of echocardiography for assessing perioperative cardiac risk in patients undergoing noncardiac surgery can not be supported. Only patients with suspected relevant heart valve diseases, acute heart failure, cardiomyopathy or condition after heart or heart-lung transplantation may benefit from preoperative echocardiography. In patients with suspected or proven coronary artery disease stress echocardiography offers the most relevant additional information for the anaesthesiologist. However, because of the high financial and personal implications it should be reserved to those patients who are not able to perform a normal stress test. Besides in patients in whom transthoracic echocardiography doesn't offer sufficient information or is not possible transesophageal echocardiography plays only a minor role in preoperative cardiac evaluation.     

Staphylococcus aureus cap5O and cap5P genes functionally complement mutations affecting enterobacterial common-antigen biosynthesis in Escherichia coli

BACKGROUND: Excision of large right atrial masses requires bicaval cannulation and cardiopulmonary bypass. Safe venous cannulation can be accomplished only by knowing the exact intracavitary location and extension of the mass to avoid fragmentation. Transthoracic echocardiography and intraoperative transesophageal echocardiography, although helpful, cannot always define the exact intracavitary relationships of the tumor. METHODS: We have used both intraoperative transesophageal and epicardial echocardiography to guide venous cannulation in 4 patients with large right atrial masses. Both echo images are used by the surgeon to select the exact site and method of cannulation to avoid fragmentation of the mass. Epicardial echocardiography complemented the images obtained by transesophageal echocardiography. RESULTS: The technique of combined transesophageal and epicardial echocardiography allowed safe venous cannulation in all 4 patients. Each of the right atrial masses was safely excised using case-specific cannulation techniques guided by the echocardiographic images. CONCLUSIONS: We propose the routine use of both intraoperative transesophageal and epicardial echocardiography in guiding venous cannulation for safe excision of large right atrial masses.     

Splenic mesothelial cysts mimicking lymphagiomas

The purpose of this prospective multicenter study of 350 consecutive patients who were accepted for mitral valve surgery because of severe regurgitation, was to assess the value of preoperative transthoracic and transesophageal echocardiography in predicting the surgical strategy in severe mitral regurgitation: repair or replacement. The cardiologist predicted the surgical strategy on the basis of the echocardiographic examination, according to predefined guidelines for repair and replacement. The predicted strategy and motivation thereof were compared with the surgical findings and procedure that was performed. Agreement on the basis of transthoracic echocardiography was reached in 86% of the repair patients and on the basis of transesophageal echocardiography in 89%. Agreement on the basis of transthoracic echocardiography was reached in 74% of the replacement patients and on the basis of transesophageal echocardiography in 75%. This study underlines the potential role of echocardiography in predicting the surgical procedure to be applied, provided that both surgeon and cardiologist use the same nomenclature and that the guidelines for replacement/repair are adhered to. Both transthoracic and transesophageal echocardiography appear to be equally accurate in predicting the optimal surgical procedure in this respect.     

Iodine-123-MIBG SPECT versus planar imaging in children with neural crest tumors

Iodine-123-metaiodobenzylguanidine (MIBG) SPECT was compared with 123I-MIBG planar imaging in 35 studies of 25 children with neural crest tumors. METHODS: Iodine-123-MIBG (0.070-0.140 mCi/kg intravenously) was followed at 24 hr by wholebody planar imaging and triple-detector, high-resolution thoraco-abdominal SPECT. At 48 hr, thoracoabdominal planar imaging was performed whenever a high-tissue background or gut activity interfered with the interpretation of the 24-hr planar images. SPECT views included a cine loop presentation of multiple volume-rendered projections. Two reviewers enumerated the number of abnormal sites on the planar and SPECT studies and rated the certainty of interpretation for each study on a scale from 0.1 (low certainty) to 1.0 (high). RESULTS: Abnormal uptake was noted on planar or SPECT imaging in 13 studies (seven patients). The average number of abnormal sites detected per study for all 35 studies was 2.7 for planar imaging and 2.9 for SPECT (p = not significant) (and 7.2 and 8.4 for planar and SPECT, respectively, for the 13 abnormal studies.) The certainty ratings for all 35 studies were 0.74 for planar studies, 0.82 for SPECT (p = 0.05, chi-square, compared with planar) and 0.86 for planar and SPECT combined (p = 0.01 compared with planar alone). On volume-rendered images, gut activity was seen as diffuse and/or linear intraluminal activity. CONCLUSION: When 123I-MIBG SPECT is used, the number of lesions detected is not increased, but there is a significant improvement in the certainty of interpretation over planar imaging.     

Who cares for the mentally ill? Theory and practice hours with a ''mental illness'' focus in nursing curricula in Australian universities

A 72-year-old woman with inferior myocardial infarction presented with both a pseudoaneurysm and a ventricular septal rupture detected by two-dimensional and Doppler echocardiography. The pseudoaneurysm originated from the junctional area between the inferior portion of the ventricular septum and posterior left ventricular wall. The short-axis view of two-dimensional echocardiography revealed an abrupt discontinuity of the junctional area and an echo-free space behind the left ventricular cavity. The communication orifice was 5 mm wide. Color Doppler echocardiography showed a left-to-right shunt flow from the pseudoaneurysm to the right ventricle was visualized. Combined use of two-dimensional and color Doppler echocardiography was useful for detecting a pseudoaneurysm resulting in rupture of the ventricular septum.     

Oral thymic extract for chronic hepatitis C in patients previously treated with interferon. A randomized, double-blind, placebo-controlled trial

Stress echocardiography and perfusion scintigraphy are both useful techniques in the assessment of myocardial viability. The use of one technique or the other as the first choice test depends mainly on each hospital's experience. Perfusion scintigraphy should be chosen as the first technique in the following situations: a) hospitals with little experience in stress echocardiography and a good Nuclear Medicine department; b) patients with a bad acoustic window in rest echocardiography; c) contraindication of a high dobutamine dose, and d) need of quantification of viable area. When having chosen echocardiography as the first technique, perfusion scintigraphy is indicated when the response to dobutamine of the asynergic area does not allow the confirmation or the rejection of the presence of viability.     

Exercise echocardiography with left atrial stimulation: advantages and limitations of the method

Exercise echocardiography seems a relatively reliable diagnostic technique for evaluation of patients with coronary artery disease. The prognostic aspects of the stress echo have widely been documented with the use of various stressors (exercise, dipyridamole, dobutamine, pacing). Rapid atrial pacing echocardiography is highly specific and sensitive technique for the detection of the coronary disease, especially in patients who are unable to perform an active stress test. This technique minimizes the factors decreasing image quality during exercise (chest wall movements and hyperventilation). Exercise echocardiography is safe, relatively cheap, and can be done in every hospital.