ABSTRACT: Quantitative analysis of left-ventricular (LV) aneurysms after myocardial infarction is prognostically relevant and assists in planning surgery. Three-dimensional (3D) echocardiography facilitates clear visualization of cardiac anatomy and accurate assessment of functional parameters. The aim of the present study was to determine the ability of 3D echocardiography to quantify LV aneurysms.
Ten patients with a known LV-aneurysm after myocardial infarction underwent 3D echocardiography and cardiac magnetic resonance (CMR) imaging at 1.5 Tesla within 3 days. For 3D echocardiography, a multiplanar transesophageal examination was performed with full LV coverage and the 3D dataset was analyzed offline. The LV-aneurysm was defined by a wall thickness <5 mm. The following quantitative parameters were determined: left ventricular end-diastolic and end-systolic volumes, LV myocardial mass (LV-mass) and mass of the LV-aneurysm. LV ejection fraction and percentage of aneurysm mass (%-aneurysm) were calculated.
LV volumes and ejection fraction showed a strong correlation between 3D echocardiography and CMR (r = 0.94-0.97; P < 0.01). Importantly, the mass and percentage of mass of the LV-aneurysm demonstrated a high correlation as well (r = 0.94 and r = 0.86, respectively; P < 0.01). For all parameters, the calculated bias between both methods was found to be minimal (0.8-7.6%).
Three-dimensional echocardiography proved to be a reliable tool for quantitative analysis of LV volumes, ejection fraction and aneurysm size in patients with prior myocardial infarction. In addition, 3D visualization of the complex cardiac anatomy in patients with LV-aneurysm may assist surgical procedure planning.
Echocardiography 09/2009; 27(1):64-8. · 1.24 Impact Factor
ABSTRACT: The purpose of this study was to develop a transesophageal probe that: 1) enables on-line representation of the spatial structures of the heart, and 2) enables navigation of medical instruments.
Whereas transthoracic real-time 3-dimensional (3D) echocardiography could recently be implemented, there is still no corresponding transesophageal system. Transesophageal real-time 3D echocardiography would have great potential for numerous clinical applications, such as navigation of catheters.
The newly developed real-time 3D system is based on a transesophageal probe in which multiple transducers are arranged in an interlaced pattern on a rotating cylinder. This enables continuous recording of a large echo volume of 70 mm in length and a sector angle of 120 degrees . The presentation of the volume-reconstructed data is made with a time lag of <100 ms. The frame rate is up to 20 Hz. In addition to conventional imaging, the observer can obtain a stereoscopic image of the structures examined with red/blue goggles.
It was shown in vitro on ventricle- and aorta-form agar models and in vivo that the system enables excellent visualization of the 3D structures. Shape, spatial orientation, and the navigation of various catheters (e.g., EPS-catheter, Swan-Ganz-catheter), stents, or atrial septal defect occluders could be recorded on-line and stereoscopically depicted. The size of the echo sector enables a wide field of view without changing the position of the probe.
Transesophageal real-time 3D echocardiography can be technically realized with the system presented here. The in vitro and in vivo studies show particularly the potential for navigation in the heart and large vessels on the basis of stereoscopic images.
Journal of the American College of Cardiology 11/2006; 48(10):2070-6. · 14.16 Impact Factor
ABSTRACT: Computer-assisted teaching and learning tools offer new opportunities for improving education and training of medical professionals. CAMPUS represents a software for computer-based, problem-oriented learning. It is a case-based training system which provides the patient's history within a highly realistic, multimedia format. Thus, the interactive design is expected to challenge, test and improve the medical knowledge and the diagnostic skills of the students. The objective of the present study was to introduce CAMPUS as a computer-based learning tool and to present preliminary results with regard to acceptance and user-friendliness.
CAMPUS was evaluated by 52 students regarding quality and experienced learning success. A tutorial was conducted within separate, small-numbered groups of students, each working on one learning case. The virtual case started with a summary of the patient's leading symptoms. The students independently took the patient history and carried out the physical examination. Then, they were asked to suggest differential diagnoses, refer the patient to appropriate diagnostic examinations and were encouraged to choose adequate therapeutic strategies. Subsequently, the quality of CAMPUS and the subjective learning success were evaluated with a standardized questionnaire.
Nearly all students described the user interface as visually attractive (51/52) and clearly structured (52/52). In particular, the students found the use of videos to be advantageous. A marked learning success was described by most students (46/52) and all students considered learning with CAMPUS to be effective.
CAMPUS offers an innovative training program to improve medical education and to enhance conventional teaching methods efficiently.
Medizinische Klinik 06/2006; 101(5):365-72. · 0.34 Impact Factor
ABSTRACT: Hintergrund und Ziel:Der Einsatz von computergestützten Lehr- und Lernsystemen bietet neue Möglichkeiten zur Verbesserung der medizinischen Aus-
und Weiterbildung. Mit CAMPUS ist ein entsprechendes Autorensystem für computerbasiertes, problemorientiertes Lernen entwickelt
worden. CAMPUS ist ein fallbasiertes Trainingssystem, das dem Studenten Patientengeschichte und entsprechende Befunde multimedial
aufbereitet und möglichst realitätsnah darstellt. Durch die interaktive Form ist der Student hinsichtlich seiner medizinischen
Entscheidungsfindung gefordert und kann gleichzeitig sein fachliches Wissen prüfen und verbessern. Ziel der vorliegenden Arbeit
war es, das computergestützte Lernprogramm CAMPUS detailliert vorzustellen und über erste Ergebnisse hinsichtlich der Akzeptanz
und Nutzerfreundlichkeit zu berichten.
Methodik:52 Studenten wurden hinsichtlich ihrer Beurteilung zu Qualität von CAMPUS und erzieltem Lerngewinn befragt. Unter ärztlicher
Anleitung wurde in Kleingruppen je ein CAMPUS-Lernfall bearbeitet. Nach der Angabe der Hauptbeschwerden des Patienten sollten
die Studenten eigenständig Fragen stellen und die körperliche Untersuchung durchführen, um anschließend mögliche Differentialdiagnosen
vorzuschlagen, durch geeignete diagnostische Maßnahmen abzuklären und entsprechende Therapiekonzepte zu entwickeln. Im Anschluss
wurden über einen standardisierten Fragebogen die Qualität des Lernprogramms sowie der subjektive Lerngewinn evaluiert.
Ergebnisse:Von nahezu allen Studenten wurde die Programmoberfläche als optisch ansprechend (51/52) und übersichtlich (52/52) eingestuft,
insbesondere der Einsatz von Videos wurde als vorteilhaft betrachtet. Der Lerngewinn wurde als groß (46/52) und das Lernen
mit CAMPUS als effektiv (52/52) beschrieben.
Schlussfolgerung:Mit CAMPUS steht somit ein innovatives Lernprogramm im Rahmen der medizinischen Aus- und Weiterbildung zur Verfügung, das
die konventionellen Lehrmethoden effektiv ergänzen kann.
Background and Purpose:Computer-assisted teaching and learning tools offer new opportunities for improving education and training of medical professionals.
CAMPUS represents a software for computer-based, problemorientated learning. It is a case-based training system which provides
the patient’s history within a highly realistic, multimedia format. Thus, the interactive design is expected to challenge,
test and improve the medical knowledge and the diagnostic skills of the students. The objective of the present study was to
introduce CAMPUS as a computer-based learning tool and to present preliminary results with regard to acceptance and user-friendliness.
Methods:CAMPUS was evaluated by 52 students regarding quality and experienced learning success. A tutorial was conducted within separate,
smallnumbered groups of students, each working on one learning case. The virtual case started with a summary of the patient’s
leading symptoms. The students independently took the patient history and carried out the physical examination. Then, they
were asked to suggest differential diagnoses, refer the patient to appropriate diagnostic examinations and were encouraged
to choose adequate therapeutic strategies. Subsequently, the quality of CAMPUS and the subjective learning success were evaluated
with a standardized questionnaire.
Results:Nearly all students described the user interface as visually attractive (51/52) and clearly structurized (52/52). In particular,
the students found the use of videos to be advantageous. A marked learning success was described by most students (46/52)
and all students considered learning with CAMPUS to be effective.
Conclusion:CAMPUS offers an innovative training program to improve medical education and to enhance conventional teaching methods efficiently.
ABSTRACT: Quantification of the left ventricular (LV) volume by three-dimensional echocardiography is accurate but time-consuming. To shorten the time required, we sought to determine the minimum number of image planes necessary to measure LV volume reliably.MethodsWe analyzed transesophageal three-dimensional echocardiographic LV data obtained by the rotational scanning method in 16 patients: 11 had ischemic heart disease, and 5 had dilated cardiomyopathy. LV volumes were calculated from 6, 10, and 30 short-axis images using the disk-summation method and from 2, 4, 6, 10, 20, and 30 longitudinal images using the new average rotation method.ResultsLV volume varied less with the average rotation method than with the disk-summation method. The 95% limit of agreement between the 30-image and 6-image methods was 0.3% 3.7% for the average rotation method, whereas it was –2.0% 6.9% for the disk-summation method. The time required for analysis decreased from 12.5 2.8min with the 30-image method to only 3.3 0.5min for the 6-image method.ConclusionsMeasurement of six longitudinal images provided reliable LV volume data, even in patients with enlarged or deformed left ventricles. The short measurement time supports the use of three-dimensional echocardiographic LV volume measurement in the clinical setting.
Journal of Medical Ultrasonics 05/2004; 31(2):59-65. · 0.33 Impact Factor
ABSTRACT: Common 3D systems have only limited spatial and temporal resolution (frame rate of 25 Hz). Thin structures such as cardiac valves are not imaged exactly; rapid movement patterns cannot be precisely recorded. The objective of the present project was to achieve radiofrequency (RF) data transmission to the 3D workstation to improve image resolution.
A commercially available echocardiographic system (5-MHz transesophageal echocardiography probe) with an integrated raw data interface enables transmission of RF data (up to 40 megabytes per second). A 3D data set may contain up to 3 gigabytes, so that all of the high-resolution ultrasound information of the 2D image is available. Frame rates of up to 168 Hz result in temporal resolution 6 times that of standard 3D systems. The applicability of the system and the image quality were tested in 10 patients. The structure of the aortic valve and the dynamic changes were depicted by volume rendering. The changes in the orifice areas were measured in frame-by-frame planimetry. The mean number of frames recorded per cardiac cycle was 122+/-16. The improved structural resolution enabled a detailed imaging of the morphology of the aortic cusps. The rapid systolic movement patterns were recorded with up to 51 frames. The high number of frames enabled creation of precise area-time diagrams. Thus, the individual phases of aortic valve movement (rapid opening, slow valve closing, and rapid valve closing) could be analyzed quantitatively.
A 3D system based on RF data enables high-resolution imaging of cardiac movement patterns. This offers new perspectives for qualitative and quantitative analyses, especially of cardiac valves.
Circulation 07/2003; 107(23):2876-9. · 14.74 Impact Factor
ABSTRACT: Knowledge of aortic valve function has been obtained from experimental studies. The aim of the present study was to investigate characteristics of aortic valve motion in humans.
Fifty-six patients were studied: 19 with normal valve and good systolic left ventricular function (Group NL), 12 with normal valve and reduced left ventricular function (Group CMP), and 25 with aortic stenosis and good left ventricular function (Group AS). The frame rate was doubled (50 Hz) compared with previous 3-dimensional systems. A mean of 38 +/- 9 images were acquired per cardiac cycle, with 14 +/- 4 images during the systole. The changes in shape and orifice area were analyzed over time.
With normal valves, valve movement proceeded in 3 phases: rapid opening, slow closing, rapid closing. Stenotic valves showed a slower opening and closing movement. The times to maximum opening in Groups NL, CMP, AS were 76 +/- 30, 88 +/- 18 (P =.06), and 130 +/- 29 (P <.01) ms, respectively. It was inversely correlated to the maximum orifice area (r = -0.59, P <.001). The opening velocities in Groups NL, CMP, AS were 42 +/- 23, 28 +/- 9 (P <.05), and 5 +/- 2 (P <.001) cm(2)/s, respectively. There was a close correlation between the opening velocity and the maximum orifice area (r = 0.87, P <.001). Slow valve closings occurred at a velocity of 8.0 +/- 5.2, 5.3 +/- 2.0 (P =.21), 2.8 +/- 1.1 (P <.01) cm(2)/s, respectively, and rapid closings in Groups NL and CMP at 50 +/- 23, 29 +/- 8 (P <.01) cm(2)/s. The results show good agreement with experimental data.
Rapid aortic valve movement can be recorded by 3-dimensional echocardiography and analyzed quantitatively. Time and velocity indices of valve dynamics are influenced by valvular and myocardial factors. A comparable in vivo analysis is not possible with any other imaging procedure.
Journal of Thoracic and Cardiovascular Surgery 07/2003; 125(6):1412-9. · 3.41 Impact Factor
ABSTRACT: Determination of cardiac output is a potentially important clinical application of three-dimensional (3-D) echocardiography since it could replace invasive measurements with the Swan-Ganz-catheter. To date, there are no studies available to determine whether cardiac output measured by thermodilution can be predicted reliably under changing hemodynamic conditions. Fifteen pigs with ischemic myocardium were examined under four hemodynamic conditions at rest and under pharmacological stress with 5, 10, and 20 microg/kg/min dobutamine. The 3-D datasets were recorded by means of transesophageal echocardiography. The endocardial definition was enhanced by administering the contrast agent FS069 (Optison). Cardiac output was calculated as the product of stroke volume (end-diastolic - end-systolic volume) and heart rate. The invasive measurements were performed with a continuous thermodilution system. In general, there was moderate correlation between 3-D echocardiography and thermodilution(r = 0.72, P < 0.001). At rest, the 3-D echocardiographic measurements were slightly but significantly lower than the invasive measurements (mean difference 0.6 +/- 0.5L/min,P < 0.001). Under stress with 5, 10, and 20 microg/kg/min dobutamine, there was a marked increase in the deviation (1.3 +/- 0.5L/min,P < 0.001; 1.6 +/- 0.7 L/min,P < 0.001; and 2.1 +/- 1.1L/min,P < 0.001, respectively). The deviation was based on two factors: (1). Under stress, the decreasing number of frames per cardiac cycle acquired with 3-D echocardiography led to imprecise recording of end-diastolic and end-systolic volumes, and thus to an underestimation of cardiac output. At least 30 frames per cardiac cycle are needed to eliminate this effect. (2). There is a systematic difference between 3-D echocardiographic and invasive measurements, which is independent of the imaging rate. This is based on an overestimation of the true values by thermodilution. In conclusion, cardiac output can be determined correctly by 3-D echocardiography for normal heart rates at rest. At elevated heart rates, the temporal resolution of 3-D systems currently available is not adequate for reliable determination. In performing and evaluating future clinical comparative studies, the systematic difference between 3-D echocardiography and thermodilution, based on overestimation by thermodilution, must be taken into account.
Echocardiography 02/2003; 20(1):47-55. · 1.24 Impact Factor
ABSTRACT: Aortic stenosis is a challenge for three-dimensional (3-D) echocardiographic image resolution. This is the first study evaluating both 3-D anyplane and 3-D volume-rendered echocardiography in the quantification of aortic stenosis. In 31 patients, 3-D echocardiography was performed using a multiplane transesophageal probe. Within the acquired volume dataset, five parallel cross sections were generated through the aortic valve. Subsequently, volume-rendered images of the five cross sections were reconstructed. The smallest orifice areas of both series were compared with the results obtained by two-dimensional (2-D) transesophageal planimetry and those calculated by Doppler continuity equation. No significant differences were found between Doppler (0.76 +/- 0.18 cm(2)), 2-D echocardiography (0.78 +/- 0.24 cm(2)), and 3-D anyplane echocardiography (0.72 +/- 0.29 cm(2)). The orifice area measured smaller (0.54 =/- 0.31 cm(2), P < 0.001) by 3-D volume-rendered echocardiography. Bland-Altmann analysis indicated that for 3-D anyplane echocardiography, the mean difference from Doppler and 2-D echocardiography was - 0.04 +/- 0.24 cm(2) and - 0.06 +/- 0.23 cm(2), respectively. For 3-D volume-rendered echocardiography, the mean difference was -0.23 +/- 0.24 cm(2) and - 0.25 +/- 0.26 cm(2), respectively. In the subgroup with good resolution in the 3-D dataset, close limits of agreement were obtained between 3-D echocardiography and each of the reference methods, while the subgroup with poor resolution showed wide limits of agreement. In conclusion, planimetry of the stenotic aortic orifice by 3-D volume-rendered echocardiography is feasible but tends to underestimate the orifice area. Three-dimensional anyplane echocardiography shows better agreement with the reference methods. Accuracy is influenced strongly by the structural resolution of the stenotic orifice in the 3-D dataset.
Echocardiography 01/2002; 19(1):45-53. · 1.24 Impact Factor