Nuclear magnetic resonance in congenital cardiopathies in adults

Magnetic resonance imaging is a newly developed diagnostic technique recently used for the study of the cardiovascular system. One of the most promising fields of application for magnetic resonance is the study of congenital heart diseases. Since it offers high contrast and resolution tomographic images of the heart, this technique appears particularly suitable for the anatomic assessment of cardiovascular malformations. In order to evaluate the potential of magnetic resonance imaging in the evaluation of congenital heart diseases, we reviewed 21 cases of cardiac malformations (age: 9-81, mean: 48 +/- 23). Two dimensional echo-cardiography was performed on all of them. Out of the 21 patients, 13 were imaged to confirm previous diagnoses based on echocardiographic (8) or angiographic (5) data. Four more patients underwent a cardiac angiography after the magnetic resonance study. The remaining eight patients were imaged due to a poor echocardiographic examination (4) and for other reasons (4). Eight patients had an atrial septal defect, 1 had a patent foramen ovale, 2 had a ventricular septal defect, 1 had a corrected transposition of the great vessels, 2 had an aortic coarctation, 2 had a developmental venous abnormality, 5 had different congenital diseases of the aorta or of the pulmonary valve or artery. Image quality was optimal in 18 out of the 21 patients studied (85.7%). In the remaining 3 subjects image quality enabled a diagnosis. In all patients magnetic resonance imaging correctly depicted the cardiac malformation and in some cases furnished data on the severity of the disease. In 9 cases (4 atrial septal defects, 2 developmental venous abnormalities, 2 aortic aneurysms, 1 right pulmonary artery atresia) magnetic resonance imaging provided the diagnosis. These data indicate that magnetic resonance imaging may represent an important non-invasive diagnostic tool capable of offering valuable information on adult patients with suspected congenital heart disease. It is also possible to foresee that this technique will play an outstanding role as a non invasive alternative imaging technique whenever echocardiography cannot be performed is not satisfactory. Furthermore, magnetic resonance imaging should be considered a major diagnostic technique to be used for the anatomic study of the heart prior to resorting to angiography.     

Preliminary Report on Use of 3-Dimensional Computed Tomographic Images in a Disease-Based Transesophageal Echocardiographic Simulation System

We used 3-dimensional computed tomographic images to create a disease-based transesophageal echocardiographic simulation system for complex congenital heart defects.We enrolled 7 pediatric patients with complex congenital heart defects in this proof-of-concept study. Preoperative computed tomographic images and intraoperative transesophageal echocardiographic images were acquired for all patients. Two- and 3-dimensional computed tomographic cross-sectional images were created to simulate the process of transesophageal echocardiographic image acquisition. Computed tomographic images simulating the midesophageal 4- and 5-chamber views, aortic valve short-axis views, long-axis views, and ascending aortic short-axis views were created to correspond with the actual transesophageal echocardiographic images from each patient. Four reviewers then evaluated the image quality of the computed tomographic images, the agreement between the echocardiographic and tomographic images, and the ability of the 3-dimensional computed tomographic full-volume and cross-sectional images to yield the spatial and temporal congruence of transesophageal echocardiograms.In most of the patients, computed tomography yielded images of good-to-excellent quality. Strong agreement was noted between the computed tomographic and transesophageal echocardiographic images acquired in the same patients. The ability of 3-dimensional computed tomography to yield the spatial and temporal congruence of transesophageal echocardiography in selected planes was also good to excellent.We found that 3-dimensional computed tomographic images can simulate the process of transesophageal echocardiography in acquiring the echocardiographic image clearly. This imaging method has the potential to be applied successfully to a disease-based transesophageal echocardiographic simulation system.Key words: Adult health personnel/education, computer graphics, echocardiography, transesophageal/instrumentation, heart defects, congenital/ultrasonography, image processing, computer-assisted/methods, imaging, three-dimensional/methods, tomography, x-ray computed/methodsTransesophageal echocardiography (TEE) is one of the most important tools in cardiology and cardiovascular anesthesiology. It reveals information about heart anatomy and function, thereby helping to detect and exclude diseases, in addition to guiding surgical treatment or medical therapy.¹ Learning to perform TEE is a challenge because of the difficulties in reconstructing 3-dimensional (3D) images from 2-dimensional (2D) slices and in understanding the spatiotemporal relationships as well as the omniplane rotation.² This becomes more complicated, sometimes even for experienced echocardiographers, in patients who have complex congenital heart defects caused by altered heart anatomy. In addition, TEE is a semi-invasive procedure that should be performed relatively quickly, and it should not be repeated or conducted purely for educational purposes.On the basis of the concept of “augmented reality,” several TEE simulation systems have been introduced as methods of TEE training.^3–5 However, because pathologic changes in the heart can be complex, not all cardiac pathologic states are fully incorporated into these simulators. A disease-based simulation system has not been available.Because of technological advances, cardiac computed tomography (CT) enables the acquisition of high-resolution, real-time 3D images of the heart, including its internal structure.^6,7 Accordingly, these images can simulate the process of TEE in acquiring the image and providing the augmented reality. In this study, we report our initial results from our use of 3D CT images to create a disease-based TEE simulation system for complex congenital heart defects.     

Visualization of Secundum Atrial Septal Defect Using Transthoracic Three-Dimensional Echocardiography in Children: Implications for Transcatheter Closure

BACKGROUND: The objective of this study was to evaluate the efficacy of quantitative measurements of secundum atrial septal defect (ASD) with dynamic transthoracic three-dimensional (3-D) echocardiography. METHODS: Twenty-six patients (age, 13 months to 14 years; mean age, 37 months) with secundum ASDs underwent 3-D echocardiographic imaging generated from transthoracic echocardiographic interrogation before surgery. Four specific cut planes were defined: four-chamber view, transverse view, en face view from right and left atrial side. The images obtained from 16 patients clearly demonstrated all four defined cut planes for the quantitative measurement. RESULTS: The defect sizing determined by the 3-D images correlated well with surgical findings. These images may be interactively manipulated to optimize visualization of the defect to allow the cardiologist to perform transcatheter occlusion. A significant correlation was demonstrated to the limbic band tissue assessment by four-chamber and transverse views. Unusual atrial structures such as muscle bands and the fore-shortening of the en face view might induce biased measurements. CONCLUSIONS: The transthoracic approach was successful in capturing sufficient data to create 3-D images, which can provide an accurate assessment of secundum ASD. The possibility of underestimation should always be taken into account with the en face view. Multiple cut planes were essential to ensure correct sizing for adequate selection of the occluder.     

Dreidimensionale Rekonstruktion der Pulmonalvenen und des linken Atriums

BACKGROUND: Selective pulmonary vein (PV) isolation to eliminate triggers is commonly used for curative catheter ablation of atrial fibrillation guided by two-dimensional (2-D) PV angiography, which is somewhat limited to depict the complex morphology of the PVs. 3-D mapping systems are limited to reconstruct the complete "true" anatomy by the reach of the mapping electrode related to catheter properties (maximum deflection and curve). New 3-D imaging systems (spiral computed tomography [CT] or magnetic resonance imaging [MRI]) provide detailed knowledge of the individual left atrial and PV morphology. Especially with the tampering, funnel-shaped PV ostia, identification of the PV ostium in selective PV isolation procedures aiming at the interruption of myocardial fibers is rather challenging using the 2-D imaging technique of contrast angiography. PATIENTS AND METHODS: In a total of 16 patients (13 male, three female, mean age 57 +/- 8 years), cardiac 3-D magnetic resonance angiography (MRA; 1.5 T, ACS Intera Philips, Germany) using an ECG-gated technique (1.3-1.7 mm slices) was performed. Using the postprocessing software Leonardo (Siemens, Germany), all adjacent anatomic structures such as the pulmonary artery were cut off to focus on the left atrium (LA) and PV anatomy. RESULTS: Left-sided PVs always entered in close proximity into the LA (common ostium in two patients). The right PVs entered more separately into the LA with a predominance of oval shapes. CONCLUSION: MRA is a noninvasive tool providing knowledge of the individual 3-D anatomy in a photorealistic fashion. Ultimately, image fusion with 3-D mappings systems would allow for true 3-D electrophysiologic mapping and could facilitate further understanding of the underlying substrate of so far "unsolved" complex arrhythmias such as atrial fibrillation in the future.     

Dynamic three-dimensional echocardiography with a computed tomography imaging probe: initial clinical experience with transthoracic application in infants and children with congenital heart defects.

OBJECTIVE--To assess the clinical applicability of a prototype computed tomographic echocardiographic imaging probe in paediatric patients with congenital heart disease. DESIGN--A phased array echocardiographic transducer (64 elements, 5 MHz) mounted on a sliding carriage was used transthoracically in various positions on the chest. The transducer moves from the outflow tract to the apex of the heart in 0.5 to 1.3 mm increments and records a tomographic slice of the heart at each increment level. Parallel images are recorded at a frame rate of 25-30 images/s. At each level a complete cardiac cycle is recorded. The images are digitised and stored in the image processing computer, which reconstructs the anatomical structures of the heart in a three-dimensional format by means of different grey scales. PATIENTS--45 paediatric patients (age range 3 days to 17 years) with various congenital heart defects who had been admitted to hospital for diagnostic or therapeutic cardiac catheterisation or surgery. RESULTS--Good quality echocardiographic pictures were obtained in all but two of the 45 patients. Three-dimensional reconstructions of the heart were possible from transthoracic echocardiograms. The recorded cardiac chambers and valves were displayed in three-dimensions in real time (four-dimensionally). The heart was also displayed in real time in any desired plane and in up to five planes simultaneously without having to change the position of the transducer on the chest. Different parts of the heart were displayed in a view similar to that seen by a surgeon during an operation. Image acquisition took 3-5 minutes and three-dimensional reconstruction of various cardiac structures 20-90 minutes. CONCLUSIONS--The computed tomographic imaging probe facilitates acquisition of echocardiographic data as multiple planes can be obtained from one transducer position. Display of three-dimensional structures of the heart may enhance the understanding of cardiac anatomy.     

Visualization of Secundum Atrial Septal Defect Using Transthoracic Three-Dimensional Echocardiography in Children

Background: The objective of this study was to evaluate the efficacy of quantitative measurements of secundum atrial septal defect (ASD) with dynamic transthoracic three-dimensional (3–D) echocardiography. Methods: Twenty-six patients (age, 13 months to 14 years; mean age, 37 months) with secundum ASDs underwent 3-D echocardiographic imaging generated from transthoracic echocardiographic interrogation before surgery. Four specific cut planes were defined: four-chamber view, transverse view, en face view from right and left atrial side. The images obtained from 16 patients clearly demonstrated all four defined cut planes for the quantitative measurement. Results: The defect sizing determined by the 3-D images correlated well with surgical findings. These images may be interactively manipulated to optimize visualization of the defect to allow the cardiologist to perform transcatheter occlusion. A significant correlation was demonstrated to the limbic band tissue assessment by four-chamber and transverse views. Unusual atrial structures such as muscle bands and the fore-shortening of the en face view might induce biased measurements. Conclusions: The transthoracic approach was successful in capturing sufficient data to create 3-D images, which can provide an accurate assessment of secundum ASD. The possibility of underestimation should always be taken into account with the en face view. Multiple cut planes were essential to ensure correct sizing for adequate selection of the occluder.     

Volumetric Holography of Cardiac Defects in Humans: Initial Clinical Experience Using Tomographic Echocardiographic Data

We have previously described a method to develop holograms that does not entail the presence of laser light source in the clinical environment. Although we have demonstrated the feasibility of holography from cardiac ultrasound data to depict normal and abnormal cardiac anatomy in experimental studies, the ability of holography from ultrasound data to image structural cardiac anomalies in patients is not known. In this exploratory study, we addressed the question of whether it was possible to image cardiac pathology by holography in patients with mitral valve disease, atrial septal defects, and ventricular aneurysms. Parallel, tomographic echocardiographic data obtained during transesophageal echocardiography were used to generate holograms of cardiac disorders. Holographic three-dimensional (3-D) reproduction contains up to 1024 by 1024 pixels and full gray scale in each of the individual slices. Holograms of cardiac defects depicted their true spatial location, which not only enhanced the anatomic appreciation of the defect itself, but also revealed the depth and the relationship of the structures in proximity of the defect. Thus, 3-D imaging of cardiac anomalies by volumetric multiplexed holography is feasible.     

Echocardiographic and anatomic findings in atrioventricular discordance with ventriculoarterial concordance

Atrioventricular (AV) discordance with ventriculoarterial (VA) concordance is a rare form of congenital heart disease that consists of 5 different anatomic types. The salient therapeutic consideration uniting these 5 different anatomic entities is that anatomic correction can be achieved by an atrial switch procedure with closure of any associated septal defect. Three patients who had AV discordance with VA concordance are presented, with emphasis upon 2-dimensional echocardiographic diagnosis and surgical management. One of these patients had ventricular inversion with inverted normally related great arteries in situs solitus (i.e., [S,L,I]), thus representing a form of congenital heart disease that until now has not been documented anatomically. Although these are complex defects, multiple-plane imaging with 2-dimensional echocardiography was found to be extremely reliable in ascertaining the anatomy when a comprehensive, segmental analysis is applied. This approach includes determination of visceroatrial situs, ventricular loop and great arterial position and alignment. A surgical approach to closure of the ventricular septal defect through the left-sided infundibulum in isolated ventricular inversion afforded excellent exposure of the defect and avoided AV conduction block.     

Echocardiography from the gastric fundus. Description of new projections]

Two new transgastric echocardiographic views obtained using the transesophageal probe are described. The first one (RVOT-MPA view) presents RVOT, pulmonic valve and proximal MPA. The second one (LVOT--Ao view) shows ascending aorta, aortic valve, LVOT, perimembranous area and anterior part of the trabecular septum, mitral valve with its attachment to the anterior papillary muscle and LA. The latter view corresponds to the standard subcostal view. Repeatability and applicability of these two scans were investigated on 25 pts: 10 with valvular heart disease (including 2 after valve replacement and 1 intraoperative study), 3-VSD, 2-TF, 2-ASD II, 5 with aortic aneurysm (including 1 after surgery), 3 after MI. RVOT-MPA view was obtainable in 76% pts, whereas LVOT-Ao view in 84% pts. This latter scan appeared to be very helpful in detecting VSD--either isolated perimembranous or malalignment in TF. In one pt with TF the detailed anatomy of RVOT, MPA and pulmonic arteries could be clearly imaged in fashion resembling standard echocardiographic subcostal short axis view. Left ventricular--right atrial communication was also readily appreciated in one of the pts. This view confirmed also some other informations, previously achieved by means of TEE planes (eg thrombus in LAA, aortic intimal flap protruding into LVOT). RVOT-MPA projection did not reveal more anatomical data than standard TEE planes in the investigated group. However, it should be useful in diagnosing subpulmonic VSD because of its similarity to the corresponding view available with newer TEE probes which provide longitudinal scans of the heart. The results presented proved usefulness of the new echocardiographic views, particularly in detecting VSD and more complex heart defects.     

Accuracy of two-dimensional echocardiography in the diagnosis of congenital heart disease

To assess the accuracy of 2-dimensional (2-D) echocardiography in the evaluation of cardiac anatomy in patients with congenital heart disease, 2-D echocardiograms were performed in 126 infants and children before cardiac catheterization and angiocardiography. The segmental echocardiographic analysis included determination of intracardiac, great artery, systemic venous and pulmonary venous anatomy. The 126 patients had 259 separate cardiovascular abnormalities, of which 226 (87%) were prospectively identified by 2-D echocardiography. There were 8 false-positive diagnoses. The most common lesions and the sensitivity and specificity of echocardiography were: patent ductus arteriosus, 41 patients (83% and 100%, respectively), ventricular septal defect, 35 patients (86% and 100%); atrial septal defect, 26 patients (85% and 99%); pulmonary valve stenosis, 25 patients (77% and 97%), transposition of the great arteries, 16 patients (100% and 100%); and total anomalous pulmonary venous connection, 14 patients (85% and 100%). Less common defects and their rate of detection included coarctation of the aorta, 10 of 12 patients; atrioventricular canal, 10 of 10 patients; tetralogy of Fallot, 10 of 10 patients; aortic valve stenosis 8 of 8 patients; right aortic arch, 8 of 8 patients; interrupted aortic arch, 4 of 4 patients; and unilateral pulmonary vein atresia, 0 of 1 patient. In 33 patients (26%), the errors in echocardiographic analysis were judged to have surgical importance. Most errors were the result of overlooking or misinterpreting data that had been appropriately recorded on videotape. Pulmonary valve stenosis and patent ductus arteriosus are the lesions most likely to be misdiagnosed by ultrasound studies relying on imaging alone.     

Pränatale Herzdiagnostik mittels zwei- und dreidimensionaler Fetalechokardiographie

INTRODUCTION: With increasing experience of obstetric sonographers, a higher proportion of cardiac malformations is found antenatally. However, undiagnosed fetal cardiac defects still result in a significant pre- and postnatal morbidity and mortality. The purpose of two- and three-dimensional echocardiographic imaging in the fetus is to provide clear representations of the underlying cardiac and vascular anatomy. Studies on pre- and postnatal echocardiography have shown these techniques to provide an adequate form of image display for comprehensive assessment of most cases with congenital heart disease. METHODS: To date, two different methods are used for three-dimensional echocardiography in the fetus. The technique currently employed at numerous institutions derives from a complex assembly of sequentially acquired and reconstructed two-dimensional images and is analogous to the 3-D technology assessed in studies on neonates, children, and adults. Although an electromagnetic location device is used to register transducer position during data acquisition, this technique has important limitations due to fetal movement artifacts and difficulties in cardiac gating. This often results in inadequate image quality when compared with 2-D echocardiography. Recent progress in the design and fabrication of higher-frequency real-time volumetric transducers has greatly improved 3-D echocardiographic imaging resolution and allows more immediate three-dimensional "on-line" analysis of cardiac anatomy. CONCLUSIONS: Advantages of 3-D fetal echocardiography include the ability to slice the acquired 3-D volume data into an infinite number of two-dimensional cross sections, and the ability to reconstruct unique three-dimensional views not seen with two-dimensional imaging. However, considering the current limitations and the time needed for 3-D image processing, its practical clinical relevance in the antenatal situation is not yet clear.     

3-D echocardiography: new developments and future prospects

Due to limitations in transthoracic and occasionally transesophageal 2-D echocardiography with respect to volumetric analysis and morphologic and functional assessment in patients with congenital malformations and valvular heart disease, additional diagnostic tools have been established. In parallel with the rapid evolution in computer technology, 3-D echocardiography has grown into a well-developed technique, such as volume-rendered 3-D reconstruction, capable of displaying dynamic morphology depicting depth of the structures, their attachment, and spatial relation to the surrounding tissue. Nevertheless, the complexity of data acquisition and data processing required for adequate dynamic 3-D echocardiographic imaging and volumetric analysis does not allow to use this approach routinely. The commonly used dynamic 3-D echocardiography means off-line computer-assisted image reconstruction from a series of cross-sectional echocardiographic images using currently available transesophageal and transthoracic transducers. Alternatively, real-time 3-D echocardiography based on novel matrix, phased-array transducer technology has been introduced. Although this technique can be easily combined with any routine examination, its clinical use is limited because of a lower image quality in comparison with dynamic 3-D echocardiography. Up to now, there is no transesophageal approach available using real-time 3-D echocardiography. Recently, dynamic 3-D echocardiographic technique has matured noticeably. Beside the well-known sequential scanning, which is characterized by a fixed probe and patient in space and predetermined motion of the transducer, the freehand scanning using an electromagnetic location system has found its way to clinical environment. The main advantage of this technique is that the transducer can be freely moved by the examiner and, thus, the data set acquired within a routine examination. Also 3-D rendering and display have been developed further. In this respect, especially the "real-time rendering mode" allowing the reconstructed 3-D image to be animated and moved in space and to look at it from different perspectives has gained increasing acceptance. In valvular heart disease, reconstructive surgical treatment is aspired. 3-D echocardiographic imaging is the only technique providing "surgical views" prior to opening the heart. It is capable of distinguishing particular destructive substructures of the valves and the valvular apparatus. Especially in mitral valvular reconstruction, it is of clinical importance to achieve optimal surgical results. With respect to volumetric and mass analysis, 3-D echocardiography is more accurate and reproducible in comparison with conventional 2-D analysis. It provides data independent of geometric assumptions, what may considerably influence the results in the presence of wall motion abnormalities, especially in aneurysmatic ventricles. Volumetric analysis of the aneurysmal portion may also be helpful prior to surgical resection. 3-D echocardiography can also be recommended as a valuable additional approach to atrial septal defect (ASD), corrected transposition of the great arteries, cor triatriatum, and, within limits, to ventricular septal defect (VSD) as well. Especially with respect to ASD and VSD, the potential significance of 3-D echocardiography prior to device closure is emphasized. At present, its additional information in decision-making and the increasing number of clinical cases that can be addressed and answered already justify the clinical use of this technique.     

In Vivo Imaging and Computational Analysis of the Aortic Root. Application in Clinical Research and Design of Transcatheter Aortic Valve Systems

Valvular heart disease is a major cause of morbidity and mortality in developing and industrialized countries. For patients with advanced symptomatic disease, surgical open-heart valve replacement is an effective treatment, supported by long-term outcome data. More recently, less-invasive transcatheter approaches for valve replacement/implantation have been developed for patients that are not considered surgical candidates. An understanding of valvular and paravalvular anatomy and biomechanics is pivotal for the optimization of interventional valve procedures. Advanced imaging is increasingly used not only for clinical guidance but also for the design and further improvement of transcatheter valve systems. Computed tomography is particularly attractive because it acquires high-resolution volumetric data sets of the root including the leaflets and coronary artery ostia, with sufficient temporal resolution for multi-phasic analysis. These volumetric data sets allow subsequent 3-D and 4-D display, reconstruction in unlimited planes, and mathematical modeling. Computer modeling, specifically finite element analysis, of devices intended for implantation in the aortic root, allows for structural analysis of devices and modeling of the interaction between the device and cardiovascular anatomy. This paper will provide an overview of computer modeling of the aortic root and describe FEA approaches that could be applied to TAVI and have an impact on clinical practice and device design.     

Intraoperative epicardial echocardiography: technique and imaging planes

With the recent innovations in cardiac surgical techniques, there is need for an immediate and reliable way to assess results in the operating room. Intraoperative epicardial echocardiography with Doppler color flow mapping provides an accurate and rapid imaging modality to assess the anatomical and functional results of cardiac surgery. This gives the surgeon a way to determine whether the hemodynamic abnormality has been successfully eliminated, prior to closure of the chest. After enclosure in a sterile sheath, a standard echocardiographic transducer is placed directly onto the epicardial surface. The heart is imaged in multiple tomographic planes developed specifically for intraoperative use: the parasternal equivalent; aortopulmonary sulcus; subcostal equivalent; and aorta-superior vena cava transducer positions. Two-dimensional echocardiography is useful to assess the morphology of valves and the size and function of cardiac chambers. Doppler color flow mapping provides a semi-quantitative assessment of the severity and physiological mechanism of valvular regurgitation. Continuous-wave Doppler echocardiography is used to estimate gradients across stenotic valves. This comprehensive appraisal of cardiac anatomy and flow is useful in the pre- or postcardiopulmonary bypass phase of cardiac surgery. This review focuses on the technique of intraoperative echocardiography and its applications in valve reconstruction operations with specific emphasis on the epicardial imaging planes.     

Three-Dimensional Echocardiography of Right Heart Pathology

Three-dimensional (3-D) echocardiography uses sequentially acquired tomography echocardiographic data, which is gated to the cardiac cycle, to reconstruct 3-D views of the heart. So far, this technique has been used primarily to evaluate left-sided heart structures. This report focuses on congenital and acquired right-sided heart pathologies that have been visualized by 3-D echocardiography. In addition to reviewing the literature, several representative figures are included illustrating the unique ability of 3-D echo to elucidate complex right heart anatomy. After a brief introduction to the technical aspects of 3-D echocardiography, the discussion centers on evaluation of congenital heart disease and right-sided masses, determination of right ventricular mass and volume, and evaluation of right-sided valvular heart disease. Congenital heart diseases that are reviewed include atrial septal defect (location, size, efficacy of repair), ventricular septal defect, and congenital heart disease in the fetus being evaluated in utero. Evaluation of right-sided masses, including tumors, vegetations, and thrombi, is reviewed. Methods of determining right ventricular volume and mass using 3-D echo are discussed. Evaluation of valvular heart disease, including Doppler analysis of regurgitant flow, is examined. Finally, special attention is given to the perioperative and intraoperative use of 3-D echocardiography for patients with these conditions. The conclusion summarizes the current and potential future uses of 3-D echocardiography.     

The contribution of magnetic resonance imaging in congenital heart diseases

The diagnostic value of magnetic resonance imaging (MRI) was assessed in 30 patients with congenital heart disease, including 7 patients with postoperative sequellae. The images obtained by synchronizing the MRI spectrometer with the electrocardiogramme were recorded in 2 or 3 different planes (sagittal, frontal and transverse) and compared to clinical, angiographic and/or echocardiographic data. The MRI provided high resolution tomographic images enabling spatial reconstitution of the heart by the use of different planes. These images were particularly useful for showing the position and dimensions of the ventricles (both chamber size and wall thickness) and their relationship to the atria and great vessels. These results confirm the value of this new non-invasive imaging technique in the diagnosis of congenital heart disease, not counting the additional information on blood flow and tissue characterisation that will soon become available.     

Comparison of M mode echocardiography and pathologic findings in the hypoplastic left heart syndrome

The M mode echocardiograms and pathologic specimens from 18 infants with the hypoplastic left heart syndrome were compared to determine the accuracy with which the echocardiogram reflects the state of the mitral valve, left ventricle and aortic valve, and its limitations in establishing this diagnosis. Mitral valve echoes were recorded in 7 of the 11 cases with an anatomic mitral valve orifice diameter greater than 3 mm. Ventricular septal echoes were found only in the seven cases in which the mitral valve was recorded. Differences between echocardiographic and anatomic left ventricular internal dimensions were not statistically significant in this small group. When aortic valve echoes were recorded, this valve was always patent in the anatomic specimen. The aortic valve was atretic in 9 of the 11 cases in which no aortic valve echoes were present. The echocardiographic and anatomic aortic root dimensions had a statistically significant correlation (p < 0.05), but there was considerable scatter in the data.None of the 18 infants met all of the previously proposed criteria for the echocardiographic diagnosis of hypoplastic left heart syndrome. An echocardiographic left ventricular dimension of 10 mm or greater was present in five cases (28 percent), and an aortic root dimension of 10 mm or greater in six (33 percent). The most reliable echocardiographic finding was excursion of 5 mm or less of the anterior leaflet of the mitral valve or inability to detect the mitral valve. Noninvasive findings are not always sufficient to establish the diagnosis of hypoplastic left heart syndrome, and further studies may be necessary in some patients.     

Hypoplastic left heart syndrome: is echocardiography accurate enough to guide surgical palliation?

Two-dimensional echocardiography can diagnose hypoplastic left heart syndrome. However, with the advent of the possibility of palliative open heart surgery, complete anatomic diagnosis is necessary. The anatomic findings of 15 neonates with hypoplastic left heart syndrome (age 1 to 10 days, mean 4.1) who had two-dimensional Doppler echocardiographic studies were compared with the results obtained by angiography (6 cases), surgery (11 cases) and autopsy (8 cases). Complete two-dimensional echocardiographic examination of the aortic arch, pulmonary and systemic venous return, atrial septum, ductus arteriosus and proximal coronary arteries was possible in all 15 neonates and correctly diagnosed hypoplastic left heart syndrome in each. Anatomic two-dimensional echocardiographic assessment was accurate in 13 (86%) of the 15 neonates and there were no false positive results. Undiagnosed associated abnormalities were hypoplasia of a left pulmonary artery in one patient and left superior vena cava in another. Accurate quantitation of the size of the tricuspid valve anulus, ascending aorta, pulmonary anulus and right and left pulmonary arteries was possible. Doppler examination was performed in seven patients and confirmed retrograde aortic arch flow and right to left systolic shunting in the patent ductus arteriosus. In selected neonates, surgical palliation can be attempted without angiography.