Object To investigate the examing methods and the visualisation rate of left and right atrial appendages in normal fetuses with two-dimensional ultrasonography (2DUS).
Methods 280 consecutive normal fetuses during gestation age 19–28 weeks were examined using GE Voluson Expert 730 or E8 ultrasound diagnostic system. All cases were divded into 2 groups according to different objectives: demonstration planes (n = 200) and Teniae sagittalis (n = 80). 200 consecutive normal fetuses′ atrial appendages were screened on the atrial appendages plane, which was between the four-chamber view (FCV) and the right ventricular outflow tract view (RVOT). The image features and the demonstrated ratios of atrial appendages at different incidence angle of ultrasonography and gestational weeks were recorded and calculated, respectively. 80 consecutive normal fetuses' right atrial appendages were screened to observe, the demonstrated ratio of teniae sagittalis at different incidence angle of ultrasonography was recorded. The demonstrated rate difference was compared by using X2 test.
Results The atrial appendages of normal fetuses can be demonstrated on the plane of atrial appendages. The visualisation ratio of left and right atrial appendages or both were 92%, 68% and 65.5%, respectively. The majority of left atrial appendages were fingerlike hook shapes, with narrower bases and longer bodys, and the endocardial surfaces were relatively smooth. Whereas the right atrial appendages were obtuse-angled triangle shapes, with broad bases and shallower bodys. On endocardial surface the pectinate muscles were often seen, which looked like serrated echoes. The display rate of taenia sagittalis in the right atrial appendages was 65% (52/80). There was significant difference between the ultrasonic incidence angle (p < 0.05). When ultrasound beam entranced into chest from the right side, the display situation of left-right atrial appendages and right atrial appendages were good (p <0.007). The left atrial appendages was better whatever any angles (p < 0.001). The best time to observe atrial appendages was 22 to 24 week of pregnancy.
Conclusions Atrial appendages of normal fetuses can be visualised on atrial appendages plane with 2DUS. There were differences in ultrasonographic features between left and right appendage on atrial appendages plane, expecially teniae sagittalis, which is very help to distinguish from each other. There were useful to deside the atrial situs according to the morphologic and structure of appendages, but still to be studied and comfired.