Ultrasound Imaging Of Atrial Appendages In Normal Fetuses

Object: To investigate the visualization rate，examing methods，sonographical of left and rightatrial appendages in normal fetuses with two-dimensional and three-dimensionalultrasonography（2DUS/3DUS）.Methods:280consecutive normal fetuses during gestation age19-28weeks from November2011through December2012were examined using GE Voluson Expert730or GE VolusonExpert E8ultrasound diagnostic system with Spatio-temporal image correlation technology（STIC）. All cases were divded into2groups according to different objectives:demonstration plane（sn=200）and Teniae sagittali（sn=80）.200consecutive normal fetuses′atrialappendages were screened on transverse section,which was between four-chamber view ofheart(FCV) and the view of right ventricular outflow tract view(RVOT).The right atrialappendage were screened on sagittal plane of superior-inferior vena cava(S+IVC).Allfetuses′three-dimensional volumes acquired from transverse section of atrialappendages.Two-dimensional images and three-dimensional volumes were stored on a database.STIC datasets were analysed with software of4D View.Images were reconstructed usinginversion mode and tomographic ultrasound imaging （TUI）mode. All cases were divided intofour groups by different incidence angle of ultrasonography,or three groups by differentgestational weeks.Image features and the demonstrated ratios of atrial appendages at differentincidence angle of ultrasonography and gestational weeks were recorded andcalculated,respectively.80consecutive normal fetuses′right atrial appendages were screened toobserve,the demonstrated ratio of teniae sagittalis at different incidence angle of ultrasonographywas recorded. The demonstrated rate difference was compared by using X2test.4fetuses as casegroup which was diagnosised as heterotaxy by ultrasound pranatally.Results: Atrial appendages of normal fetuses can be demonstrated on the plane of atrialappendages,which was between the view of FCV and RVOT.The visualization ratio of left,rightand left-right atrial appendages was92%,68%,65.5%,respectively. There was significantdifference between four groups of ultrasonic incidence angle for left,right and left-right atrialappendages（P＜0.05）.But only for right and left-right atrial appendages,there was significantinterclass difference（P＜0.007）.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）. when ultrasound beam entranced into chest from the left or right side, the displaysituation of left atrial appendages was good. The best time to observe atrial appendages was22to24week of pregnancy. Two-dimensional and three-dimensional images of atrial appendagewere observed. The majority of left atrial appendages were fingerlike hook shapes, withnarrower bases and longer bodys,and the endocardial surfaces were relatively smooth.Sometimeswith incisures on external edges.Whereas the majority of right atrial appendages wereobtuse-angled triangle shapes,with broad bases and shallower bodys.On endocardial surface thepectinate muscles were often seen,which looked like serrated echoes, taenia sagittalis werescanned in some cases which was between the right wall of right atrium and the top of rightatrial appendage.The right atrial appendage were displayed on sagittal plane of superior-inferiorvena cava(S+IVC).The shape of right atrial appendage were classified into four types：inversedL-shaped，horizontal， L-shaped and undefined.The display rate of taenia sagittalis was65%(52/80).4fetuses as case group which was diagnosed as heterotaxy by ultrasoundpranatally.3cases’s ultrasonographic features of appendages did correspond to diagnosispranatally,1case’ did not correspond to diagnosis postmortem.Conclusions: Atrial appendages of normal fetuses can be visualized using ultrasonography on atrialappendages plane with2DUS. The right atrial appendage can on sagittal plane of superior-inferior venacava(S+IVC).3DUS can provide more morphologic and structure information.There weredifferences in ultrasonographic features between left and right appendage on atrial appendagesplane,expecially teniae sagittalis，which is very help to distinguish from each other.There wereuseful to deside the atrial situs according to the morphologic and structure of appendages,but stillto be studied and comfired.