New Insights into Sinus Venosus Defects from Cross-Sectional Imaging

Sinus venosus defects include two varieties,superior and inferior sinus venosus defects.The superior sinus venosus defect is characterized by abnormal communication between two closely related venoatrial structures:1)the normally positioned superior vena cava-right atrium complex and 2)the right pulmonary vein-left atrium complex that is displaced leftward,forward and upward.Inferior sinus venosus defects primarily involve the inferior vena cava-right atrial junction while the right pulmonary vein-left atrial junction can also be affected.Because of the rarity and wide variation of the defects,the morphological characterization of sinus venosus defects is inconsistent among investigators and often inaccurate.Modern imaging technologies with high spatial and temporal resolutions have allowed accurate and detailed assessment of the pathological anatomy in larger numbers of cases.In this pictorial essay,we revisit the established and controversial features of the sinus venous defects using twodimensional(2D)and three-dimensional(3D)images obtained by magnetic resonance(MR)or computed tomography(CT)with brief discussion on imaging and treatment strategies.

Partial Anomalous Pulmonary Venous Connection and the Nature of Associated Sinus Venosus Defect

Background:Partial anomalous pulmonary venous connection(PAPVC)is frequently associated with atrial septal defect(ASD),especially sinus venosus defect(SVD).Although Waggstaffe described the pathology of SVDs in 1868,the exact anatomic features and the nature of SVD remains controversial.SVDs with no posterior atrial rim were observed in recent years.However,no studies suggested that absence of the residual posterior atrial septal tissue might be the key feature of SVD.The aims of this study were to investigate if absence of posterior rim of atrial septum played a crucial role in patients with SVD.Methods:From January 2011 to December 2019,256 children with PAPVC combined ASD and 878 children with isolated ASD who underwent corrective cardiac surgery were consecutively enrolled.Comprehensive review of preoperative transthoracic echocardiography,computed-tomography images and surgical findings were performed by experienced pediatric cardiologists.The subtypes of PAPVC,locations and types of ASD,and presence of posterior atrial rim of associated ASD were investigated.Results:PAPVC was right-sided in 244 children,left-sided in 6 children,and bilateral in 6 children.In PAPVC cases,ASD without posterior atrial rim existed in 226 SVD cases.ASD without posterior atrial septum only existed in cases with one or more right pulmonary veins returning to right atrium(RA)or to RA-superior vena cava junction.In cases with isolated ASD,there were 3 SVD,and the other 875 cases were secundum ASD.Conclusions:ASD without posterior atrial rims was associated with one or more right pulmonary veins returning to RA or RA-superior venous cava(SVC)junction.For SVD,the key feature is that the defect is in the posterior of the interatrial septum with no posterior septal rim,rather than adjacent to the SVC or to the inferior vena cava.

Diagnostic value of real-time three-dimensional transesophageal echocardiography for preoperative assessment of sinus venosus atrial septal defect

Background Sinus venosus atrial septal defect（SVASD） is a rare atrial septal defect. The right-sided pulmonary veins may drain into the right atrium directly or via vena cava. Two-dimensional transthoracic echocardiography（2D-TTE） is certainly the initial choice of evaluation of SVASD but is unable to show its spatial relation to the surrounding structures and the configuration of the veins accurately. The purpose of this study was to evaluate the diagnostic accuracy of real-time three-dimensional transesophageal echocardiography（RT3D-TEE） for detecting SVASD and partial anomalous pulmonary venous connection（PAPVC）. Methods2D-TTE and RT3D-TEE were performed in 25 patients with the SVASD before surgical repair. Records of these patients were compared with surgical assessments. Results Twenty-three of the 25 patients with SVASD were detected by 2D-TTE. All the 23 patents were associated with PAPVC. Two of the 25 patients with SVASD were misdiagnosed as the secundum atrial septal defect by 2D-TTE. SVASD was demonstrated in all the 25 cases by RT3D-TEE, and 25 patents were associated with PAPVC. Conclusions RT3D-TEE is highly accurate, scientific method for displaying the location, size, shape of the defect and its spatial relation to the surrounding structures, and provides additional value to the surgeon and physicians for better understanding of spatial intracardiac morphology and making more accurate diagnosis and treatment.