Three- dimensional echocardiography - Research Paper Example

Three- dimensional echocardiography Three- dimensional echocardiography is a sonogram of the heart that uses an appropriate processing system, and a matrix array ultrasound to diagnose, manage, and follow-up the progress of patients with known or suspected heart diseases. It has of late become one of the most common technologies in cardiology because of its usefulness in providing relevant information about patients’ hearts. The three dimension Echo Box was developed by the European Association of Echocardiography. This paper aims at discussing the history and current application of three-dimensional echocardiography. Three- dimensional echocardiography uses sound frequencies of high sound waves, and due to the reflection by the heart are recorded to produce moving picture. The device used to send the sound waves into the body in known as a transducer. When the sound waves get to the heart they bounce back, and return to the transducer in form of echoes. The echoes from the hearts are converted into images that are always displayed on television monitors in form of a three-dimension image of the heart. Three-dimension echocardiography gives an image of the specific shape of the heart instead of a geometrical shape. This enables it to produce images that are more accurate as compared to the one and two-dimensional echocardiography. Three-dimensional echocardiography has evolved in a fast rate since it was first used about forty years ago. In its different stages of evolution, the use of three-dimensional echocardiography was at a point reduced to the research side of cardiology and not in the clinical setting. Only until very recently has 3D echocardiography been used by cardiologists, and echo cardiographers in hospitals and clinics. Another interesting thing is the fact that transthoracic three-dimension ultrasound has been trumped by three-dimensional trans esophageal echocardiography, especially in the operational room and surgical setting (Lange, Palka, Burstow and Godman 403). The development of three-dimensional echocardiography (3D TTE) can be traced back to almost four decades, just a short period after the arrival and development of 2D echocardiography. In the year 1974, at Stanford University, Dekker et al produced the results of their work: A System for Ultrasonically Imaging the human heart in three dimensions.2D images were retrieved according to electrocardiographic and respiratory timing. This data was developed off-line by interpolation,then reconstructed into a three-dimensional image. Using the same off-line interpretation and reconstruction process as 3D TTE, three-dimensional echocardiography (3D TEE), was introduced, and was first performed in the year 1992. In Comparison to transthoracic echocardiography, the trans-esophageal perspective, as seen by cardiologists and echo-cardiographers, more often showed superior anatomical detail. Incorporating a three-dimensional modality via TEE only served to improve the exam by ensuring better spatial relationships of anatomical structures. It was not until 1991, that every report from this had its basis on a wire-frame display of 3D information, and acoustic transducer registration systems. Initial reports on the in vitro analysis of 3D calculations indicated the error of mensuration for Left Ventricle volume and mass to be ±10 ml. Results of similar nature were given in the scrutiny on right ventricular. In 1989, a trans-esophageal perspective was considered for the first time to get wire-frame 3D data for the in vivo mensuration of LV. Three-dimensional echocardiography was found to correlate highly with cineventriculography.and had about half the variability of volume calculations as compared to 2D echocardiography (Lange et al 404). The mean difference between 3D echocardiography and cineventriculography was found to be 12.6 ml for end-diastolic volume and 6.5 ml for end-systolic volume. Agreement was realized between 3D echocardiography and volumetric cine magnetic resonance imaging. There were no differences existing between the two techniques, and volumetric magnetic resonance imaging. Three-dimension echocardiography was different by one functional category in just 8% of patients handled. The advantage of mass and volume calculation by 3D echocardiography over 2D echocardiography has in the recent past been observed in children having functionally single left ventricles. The measurement of volume by 3D echocardiography is more accurate and had shorter acquisition time as compared to the 2D echocardiography. The aim of three-dimensional echocardiography was to give cardiologists a more accurate rendition of the human heart as well as the face or surgical views of cardiac structures semi-invasively and non-invasively. The images found by the interpolation and reconstruction technique, however, was cumbersome and time consuming. This is because the process of reconstructing many 2D images into a single 3D image needed scan conversion where the scanned information had to be changed into a 3D grid; and volume renderingwith interpolation to fill in the gaps resulting to the complete 3D image. A big part of this process took place in a period of 30 minutes (Lange et al 407). Apart from the clumsy acquisition process and time constraint, three-dimensional images that resulted from reconstruction were not of quality that would be useful for diagnosis. In order to counter these limitations, Von Ramm developed an online acquisition technique in the 1990s. This technique could give details on volume using a sparse matrix array transducer. Each piezoelectric crystal at the sparse array transducer is meant to either receive or transmit ultrasound. The elements are arranged in a grid to allow the possibility of steering the beam in many directions, thus producing a 3D full volume. This technique was further improved to be able to produce near real-time 3D images. This is what was reffered to as real-time 3D echocardiography in cardiology is. In the year 2007,Philips introduced a live 3D TEE probe. The TEE probe is able to produce high quality 3D images. This capability is advocated to its closeness to the heart. The TEE probe can also give images of the heart’s valves, thus enabling cardiac surgeons and cardiologists to carry out a diagnosis and make plans, making their treatments faster and more accurate. The live 3D TEE can also be used for monitoring interventions in real-time and knowing procedure results so that further repairs can be made before the completion of the procedure. The importance of quantitative analysis of ventricular volume and mass in clinical processes is essential for many cardiovascular diseases. The accuracy and reliability of the measurement is therefore of high importance. While 2D echocardiography quantification techniques can be used for this purpose, they have limitations for instance, the requirement for geometric foreshortened views and modeling. These limitations do not apply to the use of 3D echocardiography in assessing ventricular size and function. This advantage is made credible in practice by numerous researches, proving the inferiority of 2Dechocardiography to 3D echocardiography. 3D echocardiography is superior in both EF measurements and accuracy and reproducibility of LV volumes and EF measurements. An important extra value of 3D echocardiography is the ability to evaluate regional LV function because of segmental analysis of the 3D endocardial borders during the cardiac cycle. The potential of 3D echocardiography to determine the quantity of segmental timing of endocardial systolic contraction, and thus detecting and quantifying LVintraventriculardyssynchrony, is essential in knowing which patients will have positive response to cardiac resynchronisation therapy (Lange et al 409). Three- dimensional echocardiography can be used in chamber quantification. Left ventricle chamber and quantification can be studied by the use of three-dimensional echocardiography. It uses the wide-angle mode to obtain the entire left ventricle volume. This enables cardiologists to carryout detailed analysis of regional and global wall motions. The images are displayed with either multiple short-axis views or orthogonal long axis views. Analysis of the data is then done offline with dedicated 3D software. The data can be analyzed online using software internal to the ultra sound machine. Since the data set includes the entire left ventricle volume, many slices from different directions can be acquired from base to the apex to study wall movement. When the left ventricle axes are correctly aligned, left ventricle volumes can be segment, which enables regional left ventricle function assessment. Real time three-dimensional echocardiography can be used in evaluation, and guidance for surgical valve repair. This technique is suitable for studying valve function because of the non-planar anatomy of the cardiac valves, and the related anatomic and spatial changes related to valvular heart disease. The three-dimensional echocardiography has enhanced the proper understanding of mitral valve anatomy and functions. The mitral valve is suited for three-dimensional because of the interrelation between chordae, the valve, myocardial walls, and papillary muscles. This technique provides useful insight into mitral valve structure. 3D echocardiography is used for anatomic assessment of the root morphology and aortic valve and for the calculation of the valve area in aortic stenosis. This method can be applied to delineate aortic flow patterns. This technique has demonstrated accuracy and feasibility in finding the quantity of aortic regurgitation. It can also be used in the localization and detection of aortic valve vegetation. 3D echocardiography can also be used to asses congenital outflow abnormalities, and to demonstrate morphological alterations in the valve after balloon dilation. Three-dimensional echocardiography can be used in the diagnosis and management of tricuspid and pulmonary valves diseases. In comparison to mitral and the aortic valves, the pulmonary and tricuspid valves have been minimally studied with three-dimensional echocardiography. However, this technique can be used illustrate anatomic changes with degenerative tricuspid and rheumatic valve disease. It has reconstructed congenital tricuspid valve abnormalitieswith accuracy,especiallyantrio-ventricular canal defects. As for the pulmonary valve, three-dimensional defining anatomic abnormalities relates to endocarditis and pulmonary valve stenosis (Lange et al 410). Three-dimensional echocardiography can also be used to control congenital heart disease. Clinical studies on the role of three-dimensional echocardiography in patients having congenital heart disease have put emphasis on the unique perspective given by the three-dimensional imaging. The versatility of the method in patients having simple defects in the post operative state also makes it essential in cardiology. Three-dimensional echocardiography can be used to diagnose various forms of congenital heart disease. The capability to analyze and record the whole cardiac structure and the capability to show complex spatial relationship makes it advantageous over 2D echocardiography. The value, feasibility, and accuracy of three-dimensional echocardiography have been evident in the intraoperative environment. Three-dimensional echocardiography gives accurate and frequently additional anatomic information as compared to two-dimensional echocardiography. Interactive three-dimensional TEE was instrumental in identifying folding, and distortion of the annulus as a cause of worsening mitral regulation and functional mitral stenosis during beating heart surgery. Intraoperative three-dimensional TEE is important in patients having surgery for congenital heart lesions. This is because it gives oblique and en face view of the left antrio-ventricular valve malformation in patients having reoperation for regurgitant lesions that have persisted after previous repair of atrioventricularseptal defects. Using contrast with three-dimensional echocardiography in improvement of quantification of the left ventricle volumes has various advantages. The real time three-dimensional technique gives the most practical perspective. Triggering can increase the signal-to-nose ratio making it superior to non-triggered imaging. Three-dimensional echocardiography can also be used in the evaluation of myocardial perfusion. This is enhanced by the capability to record the entire left ventricle and to determine the extent of hyper fused myocardium. The micro-bubble destruction problem remains a challenge even with the triggered imagingtechnique (Lange et al 411). Three-dimensional echocardiography is applicable in the management of hypertrophic cardiomiopathy. In such a situation the motion of the regional wall and the thickness of the wall are assessable by 3D cardiomyopathy. Regional systolic function decreases with the increase in left ventricle hypertrophy in both hypersensitive and idiopathic cardiomyopathy. Three-dimensional echocardiography provides information on morphological abnormalities of the valve leaflets and hypertrophied septum in patients having hypertrophic cardiomyopathy. It also helps in evaluation of mitral annular dynamics and geometry during cardiac cycle in patients with hypertrophic cardiomyopathy and hypertensive hypertrophy. Stress echocardiography is widely common in evaluation of patients with coronary artery disease. Real-time three-dimensional echocardiography has the ability to scan the entire left ventricle wall in a short span of time. It has also exhibited high sensitivity in detecting coronary artery disease as compared to 2D echocardiography. The three-dimensional echocardiography has a simultaneous multi-plane imaging makes it realistic to apply it for clinical stress echocardiography. Three-dimensional echocardiography is important in measurement of the left ventricle mass. By the use of three-dimension dataset, user interaction is enabled thus enhancing the identification of epicardial boundaries of the left ventricle myocardium. This information is useful to the analysis software in calculating an epicardial cast of the ventricle. With the volume of the cast, cardiologists can be able to find the volume of the left ventricle myocardium. They can then multiply by specific gravity of myocardium to find the mass of the left ventricle (Lange et al 412). 3D echocardiography analysis of the right heart function is of great significance in clinical cardiology. Elevation of diastolic pressure in the right atrium and right ventricle and impaired right ventricle feeling can be caused by right ventricular diastolic dysfunction. When there is an increase of pressure in the right atrial, the pressure is transmitted to the inferior vena cava. This results to its dilatation. Inspiratory and IVC diameter collapse can be used in estimating the RA pressure. Right heart dysfunction is a common encounter acquired heart diseases and congenital diseases in children. It has also been discovered to be closely related to patient outcomes. Evaluation of right atrium and systemic veins can be important as of right heart function in children. The information on the right ventricle diastolic function is important given the limitation of the 2D echocardiography in the assessment of right ventricle. This proves the importance of the use of 3D echocardiography in clinical cardiology. The shape of the left ventricle is an important parameter in assessing patients with left ventricle dysfunction. This is because the size of the left ventricle always increases with the deterioration of the function. In such a situation, the shape of the left ventricle becomes more globular and less elliptical. A sphericity index derived from three-dimensional left volumes is most accurate in reflecting the ventricular shape. A three-dimensional derived sphericity index can be calculated by dividing the end diastolic volume of the left ventricles by the sphere’s volume. This index is most accurate predictor of remodeling of patients after acute myocardial infarction. As much as three-dimensional echocardiography has proved to be useful to cardiology, it still has various shortcomings. Despite the fact that three-dimensional echocardiography enhances the quantification of chamber function and size, there is difficulty in performing quantitative analysis involving image interpretation changes. This is the reason as to why there is a paucity of information in support of the additive value of three-dimensional imaging. This makes three-dimensional a costly clinical cardiology process. For the three-dimensional protocol to be complete there must be acquisition of data from four transducer positions. In case all the images required in order to carry out a certain study could be acquired from this protocol, then the duration needed to perform an echocardiogram would greatly decrease. This will mean that it will only become perfect when it will be able to completely carry out complete image interpretation. Work Cited Lange, Aleksandra, PalkaPrzemysław, Burstow J Darryl, and Godman J Michael.“Three-dimensional echocardiography: Historical development and current applications”, Journal of the American Society of Echocardiography, n.p., 2001. Web. 29thOct 2013. Read More