[Pathological diagnosis of conotruncal defects by transthoracic three-dimensional echocardiography]

Recently, it has been demonstrated in several studies that three-dimensional echocardiography (3DE) with any cut view interpretation of the cardiac morphological structures and its dynamic three-dimensional display can conform to the need of accurate anatomical diagnosis of complex congenital heart diseases including conotruncal defects (CTD). 3DE can not only provide functional and morphological information of CTD to decide on surgical repair but also simulate the intra operative visualization of complex anatomical cardiac structures to improve the understanding of the anatomy of CTD, but there have been scarce studies to assess systematically the potential noninvasive diagnostic value of transthoracic 3DE for CTD in children. Thus, this study attempted to evaluate the diagnostic value of transthoracic 3DE for the pathological diagnosis of CTD in children.

HP Sonos 5500 echocardiographic system interfaced with Tomtec 3DE imaging system (echo-view 4.2 software) was used to diagnose 210 patients (132 male, 78 female, aged 0-15 years, mean 3.2 +/- 3.2 years) with CTD in Shanghai Children's Medical Center from May 2000 to November 2003, including 62 patients with double outlet right ventricle, 48 patients with transposition of great arteries, 48 patients with tetralogy of Fallot, 38 patients with pulmonary atresia with interventricular septal defect and 14 patients with persistent truncus arteriosus. Diagnostic method consisting of ten designed 3DE sectional views and Van Praagh's sequential segmental approach in congenital heart diseases was used in this study. And the results were compared with those diagnosed by two-dimensional echocardiography (2DE) and angiocardiography. Surgical findings were considered as the "gold standard".

There were 526 image acquisitions of transthoracic 3DE in the 210 patients with CTD including 200 through subcostal window, 254 through parasternal window and 72 through apical window, among which 477 image acquisitions (93.2%) could demonstrate good spatial cardiovascular structures. Meanwhile, six 3DE sectional views of the diagnostic method of the ten designed 3DE sectional views were identified for the diagnosis of CTD as follows: en-face view of atrial and ventricular septa from left ventricle (L1a); en-face view of atrial and ventricular septa from right ventricle (L2a); four-chamber view of whole-heart oblique frontal plane (Ha and Hb); en-face view of atrial-ventricular valve from atria (S1a) and en-face view of atrial-ventricular valve from ventricles (S2a). The 3DE sectional diagnosis showed that 3DE could provide more information of inner cardiac structure than 2DE, such as ventricular configuration identification, atrial-ventricular and ventricular-arterial continuity, location and shape of ventricular septal defect (VSD), and appreciation of the defects related with aorta and pulmonary arteries, etc. In 147 cases of surgical repair, both 3DE and 2DE were in accordance with the surgical findings, but 3DE had new findings in 18 (12.2%) cases and corrected the diagnoses in 10 (6.8%) cases as compared with 2DE.

The 3DE sectional diagnostic method could make a successfully sectional diagnosis of pathological morphology in CTD by demonstrating more spatial information of inner cardiac structure than 2DE and angiocardiography.