Journal of Medical Ultrasound (2012) 20, 65e71

Available online at www.sciencedirect.com

journal homepage: www.jmu-onl ine.com

REVIEW ARTICLE

Diagnosis of Transposition of the Great Arteriesin the Fetus

Jin-Chung Shih 1*, Shu-Chien Huang 2, Chia-Hui Lin 1, Tzu-Hung Lin 1,Ying-Ning Su 1, Shin-Yu Lin 1, En-Ting Wu 3, Ming-Kwang Shyu 1,Chien-Nan Lee 1

1Department of Obstetrics and Gynecology, 2Department of Surgery, and 3Department of Pediatrics, National Taiwan Univer-sity Hospital and National Taiwan University College of Medicine, Taipei, Taiwan

Received 12 October, 2011; accepted 4 November, 2011

KEY WORDSantenatal diagnosis,fetus,transposition of thegreat arteries,

ultrasound

* Correspondence to: Dr. Jin-Chungrics and Gynecology, National TaiwaNumber 8, Chung-Shan South Road, Ta

E-mail address: jcshih@ntu.edu.tw

0929-6441 ª 2012, Elsevier Taiwan LLdoi:10.1016/j.jmu.2012.04.005

Transposition of the great arteries (TGA) is a group of congenital cardiac defects characterizedby ventriculoarterial discordance. It is one of the most common cyanotic heart diseases, andmost affected neonates are undiagnosed as fetuses. The sequelae of the complex congenitalheart diseases could be severe if undiagnosed before birth. However, the outcome of fetuseswith TGA is improved with prenatal detection of this condition. The purpose of this article is toreview the gold standard and additional signs for the diagnosis of fetal TGA.ª 2012, Elsevier Taiwan LLC and the Chinese Taipei Society of Ultrasound in Medicine.Open access under CC BY-NC-ND license.

Introduction

Transposition of the great arteries (TGA) was first describedby Mathew Baillie in 1797 [1]. The term transposition wasfirst used by Farre in 1814, in which “trans” means “across”and “position” means “placement.” Transposition meansthat the aorta and pulmonary artery are placed across the

Shih, Department of Obstet-n University Hospital, 15F,ipei 10002, Taiwan.(J.-C. Shih).

C and the Chinese Taipei Society

ventricular septum. A few decades ago, Van Praagh et alsuggested that the aberrations in conotruncal developmentcould result in a continuum of malpositions of the greatarteries [2]. TGA is simply one subtype of these malposi-tions. Other subcategories of these malpositions includedouble-outlet right ventricle, double-outlet left ventricle,and anatomically corrected malposition [3].

The reported prevalence of congenital heart disease(CHD) varies between four and 10 per 1000 live births[4e6]. Due to advances in fetal ultrasound resolution andtechniques, obstetricians have the increasing ability todetect fetal CHD prenatally, thereby prompting timelyreferral for adequate perinatal management. Based on

of Ultrasound in Medicine. Open access under CC BY-NC-ND license.

66 J.-C. Shih et al.

a review of the literature, the antenatal diagnosis andtransfer of neonates with CHD could improve both short-term and long-term outcomes, especially in those withcyanotic congenital heart diseases [6,7].

In a population-based review, cardiac defects accountfor almost half of the neonatal deaths attributed tocongenital malformations [8]. Tetralogy of Fallot and TGAare the most common cyanotic heart defects, eachconstituting approximately 10% of fetal congenital heartdefects [9e13]. However, in most fetuses, TGA remainsundiagnosed before birth. According to a population-basedreview [14], TGA is diagnosed prenatally in only 17% ofaffected neonates. In contrast, approximately one-half ofcases of tetralogy of Fallot can be correctly diagnosed inutero. We conducted a comprehensive review for thediagnosis of TGA in the fetus because of this low detectionrate.

Terminology

TGA as well as other CHD are best diagnosed using thesegmental approach of the fetal heart [15e17]. To enhanceunderstanding of the terminology used in the segmentalapproach for the diagnosis of TGA, the following termsshould be clarified in advance [2,3,16,18e20].

Atrioventricular (A-V) discordance: The morphologicright atrium (RA) is erroneously connected to the morpho-logic left ventricle (LV); and the morphologic left atrium(LA) is incorrectly drained to the morphologic rightventricle (RV).

Ventriculoarterial (V-A) discordance: The pulmonaryartery (PA) arises from a morphologic LV, and the aorta (Ao)arises from a morphologic RV.

Complete transposition of the great arteries (TGA):Indicates the conditions of ventriculoarterial discordance.The Ao arises from a morphologic RV, and the PA arises froma morphologic LV. The A-V connection is correct.

Congenitally corrected transposition of great arteries(ccTGA): Refers to the condition of A-V discordance plus V-Adiscordance. In brief, the RA enters the LV, which gives riseto the PA. The LA connects the RV, which gives rise to theAo. Thus, the circulation becomes physiologically correctedalthough double errors occur.

d-loop: Denotes the normal rightward (dextro, d ) loopof the embryonic cardiac tube. The inflow portion of the RVis to the right of the morphologic LV.

l-loop: Denotes the cardiac tube bending leftward (levo,l ) during embryogenesis. The inflow portion of themorphologic RV is to the left of the morphologic LV.

Detecting transposition of the great arteries in thefetus

According to the policy of the Bureau of Health Promotionin the Department of Health of Taiwan, general practi-tioners should perform routine ultrasound to evaluatefetal growth at 20 weeks’ gestation. The diagnosis of TGAcan be made by carefully and appropriately evaluating theanatomic locations of cardiac chambers and the connec-tions between the atria, ventricles, and great arteries atthis gestational age with high-resolution ultrasound.

However, it must be emphasized that diagnostic accuracyis only half based on the literature [21e23]. The goldstandard and the additional signs of ultrasound in thediagnosis of fetal TGA are discussed in the followingparagraphs.

The localization of cardiac chambers and greatarteries

The first step in the diagnosis of fetal TGA is the localizationof the cardiac chambers and their connections with thegreat arteries [22]. This is best done by the segmentalapproach as described in the literature [15,24e26]. Thesecardiac structures can be identified on the basis of theirspecific morphologic features.

Anatomically, the differentiation of the atrial chamberis based on the morphologic aspect of the atrial append-ages. The atrial appendages are the earlike extensions ofthe atria. Typically, the RA appendage is triangular inshape, whereas the LA appendage is fingerlike [15].However, differentiation of atrial appendages is difficultduring the antenatal period. In addition, systemic andpulmonary venous connections may provide important cluesto define situs of the atria in the fetus. The supra-diaphragmatic portion of the inferior vena cava (IVC)provides a reliable landmark to identify the anatomic RA(because of the rule of venoatrial concordance) [15], andthe drainages of four pulmonary veins usually define thelocation of anatomic LA (Fig. 1A and B).

Certain features that could help differentiate the rightand left ventricles are the texture and distribution ofinternal trabeculae. The trabeculae are coarse in the RV,but thin and delicate in the LV (Fig. 1B and 1C). More-over, the papillary muscles of the RV are attached toboth the interventricular septum and the lateral wall, yetthe two papillary muscles of the LV are attached only tothe lateral wall of myocardium [15,27,28] (Fig. 1C).Nevertheless, these anatomic features may not beapparent in the fetus. The insertion of the tricuspid valveto the ventricular septum is lower than that of the mitralvalve, and the location of the moderator band in theapical area identifies the location of the RV (Fig. 1B).Both characteristics are valuable in defining themorphologic RV.

The major characteristic of the PA is that the threebranches (right and left PA, ductus arteriosus) immediatelyemerge from the main PA when it arises from the RV(Fig. 1D). In contrast, the Ao does not branch into theascending portion except for the coronary arteries. Theaortic arch can be seen by positioning the transducer tothe left parasagittal plane. In the view, the Ao is seen toarise from the middle of the fetal thorax with acutecurvature (usually described as having a ‘candy cane’appearance). Three branches from the transverse arch canbe identified as the innominate, the left common carotid,and the left subclavian arteries (Fig. 1E). The ductal archcan be seen by sliding the transducer to the left from theaortic arch (with a slight tilt of the transducer). In thenormal fetus, the ductal arch arises from the anteriorthorax with a wide curvature (usually described as havinga ‘hockey stick’ appearance). There is no branch in the

Fig. 1 (A) Parasagittal view of the fetal heart. The drainage of IVC identifies the location of the RV. (B) Four-chamber view of thefetal heart. The MB indicates the location of the morphologic RV, whereas the drainage of normal pulmonary veins denotesthe location of the LA. The trabeculae are coarse in the RV but thin and delicate in the LV. (C) Anatomically, the insertion of thetricuspid valve to the ventricular septum is lower than the mitral valve (arrows). In addition, the papillary muscles of the RV areattached to both the interventricular septum and the free wall (asterisks), yet the two papillary muscles of the LV are attached onlyto the free wall. These landmarks are useful features for the identification of the morphologic RV. (D) The major characteristic ofthe pulmonary artery is that the main pulmonary trunk branches into the right and left pulmonary arteries and the ductus arte-riosus. The ductus arteriosus is not shown here because it is at the higher position. (E) The ‘candy cane’ appearance of the aorticarch, which originates from the middle thorax. 1, the innominate artery; 2, the left common carotid artery; 3, the left subclavianarteries. (F) In the normal fetus, the ductal arch arises from the anterior thorax with a wide curvature (the ’hockey stick’appearance). Ao Z aorta; IVC Z inferior vena cava; LA Z left atrium; LPA Z left pulmonary artery; LV Z left ventricle;MB Z moderator band; MPA Z main pulmonary artery; MV Z mitral valve; PA Z pulmonary artery; PV Z pulmonary vein;RA Z right atrium; RPA Z right pulmonary artery; RV Z right ventricle; TV Z tricuspid valve.

Transposition of the Great Arteries 67

transverse portion of the ductal arch, which can be used todifferentiate the aortic arch (Fig. 1F).

‘Gold standard’ of the diagnosis of fetal TGA

The diagnosis standard of fetal TGA is the demonstration ofV-A discordance. The Ao arises from the morphologic RVwhile the PA arises from themorphologic LV [18] (Fig. 2). Thediagnosis of V-A discordance can be achieved by rotating thetransducer from the four-chamber view to the left

ventricular outflow tract view and the right ventricularoutflow tract view subsequently. Sometimes these twoviews can be obtained simultaneously in the same plane.These two views essentially establish the diagnosis of fetalTGA.

After demonstrating V-A discordance, the A-V connec-tion should be inspected to differentiate complete trans-position (d-TGA) from congenitally corrected transposition(ccTGA). If V-A discordance combined with a correct A-Vconnection is noted, the diagnosis is complete transpositionof the great arteries (d-loop TGA, or d-TGA). In contrast,

Fig. 2 The ventriculoarterial (V-A) discordance and theparallel alignment of the great arteries essentially establishthe diagnosis of transposition of the great arteries in the fetus.The asterisk indicates the location of moderator band.Ao Z aorta; LV Z left ventricle; RV Z right ventricle;PA Z pulmonary artery.

68 J.-C. Shih et al.

when V-A discordance plus A-V discordance (Fig. 3) isdemonstrated, the diagnosis is changed to congenitallycorrected transposition of the great arteries (ccTGA; l-loopTGA). These two entities should be differentiated becausethe clinical manifestation, outcome, and surgical optionsare totally different.

The additional signs of the diagnosis of fetal TGA

Several additional scanning planes and signs of the diag-nosis of fetal TGA have been described in the literature[21,22,29e33]. These additional views, although notessential to the prenatal diagnosis, may help to identify

Fig. 3 The atrioventricular (A-V) discordance. The LA, whichreceives the drainages from the PV, connects to the morpho-logic RV (identified by the presence of the moderator band).The diagnosis of ccTGA can be made in coexistence with the V-A discordance. AO Z aorta; ccTGA Z congenitally correctedtransposition of great arteries; LA Z left atrium;PV Z pulmonary vein; RV Z right ventricle.

TGA or assist diagnosis in certain conditions such as unfa-vorable fetal position or diagnostic dilemma betweensimilar pathologies. The identification of fetal TGA mayimprove perinatal outcome with well-timed transport ofthe mother to a tertiary center for neonatal cardiovascularassistance [34,35].

1. Three-vessel and trachea view: The three-vessel orthree-vessel-trachea view is a transverse view of thefetal upper mediastinum [32,36,37]. In this plane, themain PA, Ao, and superior vena cava (plus the crosssection of trachea in front of the spine) are conse-quently demonstrated from the left side (Fig. 4).However, in the fetus with TGA, this anatomicsequence is altered and usually demonstrates a solitarytransverse Ao in the same plane. The PA and superiorvena cava sometimes may be seen on the same side ofthe transverse Ao (Fig. 5).

2. The arch view: In the fetus with TGA, the aortic archmay be shifted to the anterior fetal thorax, witha ductal arch in its posterior aspect. Both arches maydemonstrate a parallel configuration without a normalspiraling relationship (Fig. 6).

3. The outflow tract view: In the normal fetus, the greatarteries emerging from the bilateral ventricles showa ‘crossover’ relationship. However, in the fetus withTGA, the great arteries are usually aligned in theparallel course, which allows visualization of both greatarteries from ventricles in a single scanning plane(Fig. 4). However, not all fetuses with TGA have thisparallel relationship of the great arteries.

4. The ‘big-eye frog’ view [21]: Using four-dimensionalspatiotemporal image correlation technique, the en-face view of the fetal A-V valves could be seen. Inthis view, the PA is at the 1-2 o’clock direction (leftanterior side) of the Ao. However, the anatomic rela-tionship is altered in the fetuses with d-TGA. In thosefetuses with TGA, the PA deviates posteriorly to thedirections of 3 or 4-5 o’clock direction of Ao (i.e., PAparallel or left posterior to the Ao) (Fig. 7).

Fig. 4 The three-vessel tracheal view through the uppermediastinum of the fetus. The pulmonary artery (PA), the aorta(Ao), and the superior vena cava (SVC) are identified. Thethymus can be seen anteriorly and the trachea posteriorly.

Fig. 5 The same scanning plane as shown in Fig. 4. Theanatomic relationship is altered in the case of fetal trans-position of the great arteries. Ao Z aorta; RPA Z rightpulmonary artery.

Fig. 7 Three orthogonal planes in a volume data set of fetaltransposition of the great arteries (TGA). The C plane identifiesthe relative locations of the PA to the Ao in this fetus. In thenormal fetus, the PA is at the 1-2 o’clock direction to the Ao.But in the fetus with TGA, the PA deviated posteriorly, eitherside-by-side (the ‘big-eye frog’ sign [21]) or to the 4-5 o’clockdirection of the Ao (as illustrated here). The axis bar shown onthe lower right area illustrates the relative position of the Cplane to the fetal body. Arrows indicate the two coronaryarteries from the ascending aorta. Ao Z aorta; PA = pulmonaryartery. RAA Z right atrial appendage; LAA Z left atrialappendage.

Transposition of the Great Arteries 69

Cardiac anomalies associated with TGA

Complete transposition of the great arteries (d-TGA)Approximately one-half of the fetuses with TGA haveassociated ventricular septal defect (VSD). The location ofVSD could be anywhere, but is most commonly found at thepart of the outlet portion with an anterior or posteriormalalignment [38]. Anterior malalignment of the outletseptum may result in aortic root stenosis and widening ofthe pulmonary tract. With a great degree of pulmonaryvalve overriding the ventricular septum (Fig. 8), TGA maymerge into the continuum of the double outlet of the rightventricle. In contrast, when there is posterior malalignmentof the outlet septum, pulmonary stenosis with overriding Ao

Fig. 6 In this scan showing transposition of the greatarteries, the spatial arrangement of the aortic arch and theductal arch is in reverse. In this fetus with congenitally cor-rected transposition of the great arteries, the aortic arch(identified by the presence of three branches in the transversearch) appears anterior to the ductal arch. Both arches arealigned in the parallel course, a finding not seen in the normalfetus.

may be seen. In this condition, it may be difficult todistinguish tetralogy of Fallot from TGA [1,7,16,18,39].

Left ventricular outflow tract obstruction (LVOTO) iscommon in d-TGA due to the posterior malalignment of theoutlet septum, resulting in a small PA in comparison to theAo (Fig. 9 A and B). In contrast, right ventricular outflowtract obstruction (RVOTO) with aortic stenosis is lesscommon in d-TGA. Premature closure of the foramen ovaleis relatively common in the fetuses with TGA, probably due

Fig. 8 The PA overrides the interventricular septum due tothe anterior malalignment (indicated by the arrow) of theoutlet septum. The asterisk indicates the location of theventricular septal defect. Ant Z anterior; Ao Z aorta;PA Z pulmonary artery; Sp Z spine.

Fig. 9 (A) The posterior malalignment of the outlet septum (indicated by the arrow) results in pulmonary stenosis and leftventricular outflow tract obstruction (LVOTO) in a fetus with transposition of the great arteries. The asterisk indicates the locationof the ventricular septal defect. (B) The same fetus as shown in (A). The posterior malalignment of the outlet septum simulta-neously results in dilated aortic root, sometimes becoming overriding aorta. Ao Z aorta; LV Z left ventricle; PA Z pulmonaryartery; RV Z right ventricle.

70 J.-C. Shih et al.

to highly oxygenated blood streaming through the foramenovale [40] (Fig. 10). When both VSD and the foramen ovaleare closed or nearly closed, the affected neonates mayrequire intensive care (including extracorporeal membraneoxygenation) immediately after birth, and early surgery.Complete transposition of the great arteries may oftencombine with atrial isomerism, common A-V canal, anddouble outlet of RV.

Congenitally corrected transposition of the great arteries(ccTGA)Complete transposition of the great arteries is often anisolated lesion. In contrast, 90% of fetuses with ccTGA willhave other cardiac malformations. Approximately 70% ofaffected fetuses have VSD, mostly in the perimembranousportion. LVOTO and tricuspid stenosis occur in 40% and 30%of fetuses with TGA, respectively. Bradycardia andcomplete A-V block were occasionally noted.

Fig. 10 Constricted foramen ovale (indicated by the arrow)in a fetus with transposition of the great arteries noted at 35weeks’ gestation. The ventricular septal defect was also nearlyclosed before birth, prompting emergency surgery during thefirst day of life.

Genetic counseling of TGA diagnosed in the fetus

The morphogenesis of the fetal heart concerns complexdevelopmental changes in the first few weeks of embryoniclife. Many chromosomal and genetic factors may contributeto the development of congenital cardiac defects. Based ona population-based case-control study, the prevalence ofchromosome aberrations in fetuses with CHD is approxi-mately 13% [41]. Most of these aberrations are trisomies 21,18, and 13. However, the incidence of chromosomeanomaly in fetuses with TGA is 0.9% [42], which is identicalto that of the normal population. DiGeorge syndromeresults from the microdeletion of chromosome 22q11,which occurs in 1 per 4000 live births [43]. Phenotypicmanifestations include cardiac defects, characteristicfacies, and thymic hypoplasia. This condition reportedly isassociated with tetralogy of Fallot or other conotruncalmalformations. However, it rarely occurs in the fetus withTGA. Extracardiac defects usually are associated with othercongenital cardiac defects, but the incidence in TGA is low.Approximately 9% of neonates with TGA are reported tohave associated extracardiac malformations, and nospecific type of malformation is described [42].

References

[1] Jaggers JJ, Cameron DE, Herlong JR, et al. Congenital heartsurgery nomenclature and database project: transposition ofthe great arteries. Ann Thorac Surg 2000;69:S205e35.

[2] Van Praagh R, Perez-Trevino C, Lopez-Cuellar M, et al.Transposition of the great arteries with posterior aorta,anterior pulmonary artery, subpulmonary conus and fibrouscontinuity between aortic and atrioventricular valves. Am JCardiol 1971;28:621e31.

[3] Van Praagh R. Transposition of the great arteries. II. Trans-position clarified. Am J Cardiol 1971;28:739e41.

[4] Hornung TS, Calder L. Congenitally corrected transposition ofthe great arteries. Heart 2010;96:1154e61.

[5] Hsiao SM, Wu MH, Jou HJ, et al. Outcome for fetuses withprenatally detected congenital heart disease and cardiacarrhythmias in Taiwan. J Formos Med Assoc 2007;106:423e31.

Transposition of the Great Arteries 71

[6] Wu MH, Chen HC, Lu CW, et al. Prevalence of congenital heartdisease at live birth in Taiwan. J Pediatr 2010;156:782e5.

[7] Skinner J, Hornung T, Rumball E. Transposition of the greatarteries: from fetus to adult. Heart 2008;94:1227e35.

[8] Abu-Harb M, Hey E, Wren C. Death in infancy from unrecog-nised congenital heart disease. Arch Dis Child 1994;71:3e7.

[9] Report of the New England regional infant cardiac program.Pediatrics 1980;65:375e461.

[10] Scott DJ, Rigby ML, Miller GA, et al. The presentation ofsymptomatic heart disease in infancy based on 10 years’experience (1973-82). Implications for the provision ofservices. Br Heart J 1984;52:248e57.

[11] Allan LD, Sharland GK, Milburn A, et al. Prospective diagnosisof 1,006 consecutive cases of congenital heart disease in thefetus. J Am Coll Cardiol 1994;23:1452e8.

[12] Moller JH, Moodie DS, Blees M, et al. Symptomatic heartdisease in infants: comparison of three studies performedduring 1969-1987. Pediatr Cardiol 1995;16:216e22.

[13] Samanek M, Slavik Z, Zborilova B, et al. Prevalence, treat-ment, and outcome of heart disease in live-born children:a prospective analysis of 91,823 live-born children. PediatrCardiol 1989;10:205e11.

[14] Chew C, Halliday JL, Riley MM, et al. Population-based study ofantenatal detection of congenital heart disease by ultrasoundexamination. Ultrasound Obstet Gynecol 2007;29:619e24.

[15] Lapierre C, Dery J, Guerin R, et al. Segmental approach toimaging of congenital heart disease. Radiographics 2010;30:397e411.

[16] Warnes CA. Transposition of the great arteries. Circulation2006;114:2699e709.

[17] Huhta JC. Evaluating the fetus with transposition. CardiolYoung 2005;15:88e92.

[18] Martins P, Castela E. Transposition of the great arteries.Orphanet J Rare Dis 2008;3:27.

[19] Marelli AJ, Mackie AS, Ionescu-Ittu R, et al. Congenital heartdisease in the general population: changing prevalence andage distribution. Circulation 2007;115:163e72.

[20] Paladini D, Rustico M, Todros T, et al. Conotruncal anomaliesin prenatal life. Ultrasound Obstet Gynecol 1996;8:241e6.

[21] Shih JC, Shyu MK, Su YN, et al. ’Big-eyed frog’ sign onspatiotemporal image correlation (STIC) in the antenataldiagnosis of transposition of the great arteries. UltrasoundObstet Gynecol 2008;32:762e8.

[22] Paladini D, Volpe P, Sglavo G, et al. Transposition of the greatarteries in the fetus: assessment of the spatial relationships ofthe arterial trunks by four-dimensional echocardiography.Ultrasound Obstet Gynecol 2008;31:271e6.

[23] Goncalves LF, Espinoza J, Romero R, et al. A systematicapproach to prenatal diagnosis of transposition of the greatarteries using 4-dimensional ultrasonography with spatiotem-poral image correlation. J Ultrasound Med 2004;23:1225e31.

[24] Abdulla R. The segmental approach to the diagnosis ofcongenital heart disease. Pediatr Cardiol 2000;21:118.

[25] Yoo SJ, Lee YH, Cho KS, et al. Sequential segmental approachto fetal congenital heart disease. Cardiol Young 1999;9:430e44.

[26] Hagler DJ. Echocardiographic segmental approach to complexcongenital heart disease in the neonate. Echocardiography1991;8:467e75.

[27] Anderson RH. Transposition e Introduction. Cardiol Young:Cambridge University Press; 2005. pp. 72e5.

[28] Allan LD. Fetal congenital heart disease: diagnosis andmanagement. Curr Opin Obstet Gynecol 1994;6:45e9.

[29] Paladini D, Volpe P, Marasini M, et al. Diagnosis, character-ization and outcome of congenitally corrected transposition ofthe great arteries in the fetus: a multicenter series of 30cases. Ultrasound Obstet Gynecol 2006;27:281e5.

[30] Tometzki AJ, Suda K, Kohl T, et al. Accuracy of prenatalechocardiographic diagnosis and prognosis of fetuses withconotruncal anomalies. J Am Coll Cardiol 1999;33:1696e701.

[31] Tennstedt C, Chaoui R, Korner H, et al. Spectrum of congen-ital heart defects and extracardiac malformations associatedwith chromosomal abnormalities: results of a seven yearnecropsy study. Heart 1999;82:34e9.

[32] Yoo SJ, Lee YH, Kim ES, et al. Three-vessel view of the fetalupper mediastinum: an easy means of detecting abnormalitiesof the ventricular outflow tracts and great arteries duringobstetric screening. Ultrasound Obstet Gynecol 1997;9:173e82.

[33] Santoro G, Masiello P, Baldi C, et al. Corrected transpositionof the great arteries with isolated aortic coarctation: inutero echocardiographic diagnosis. Pediatr Cardiol 1997;18:396e8.

[34] Kumar RK, Newburger JW, Gauvreau K, et al. Comparison ofoutcome when hypoplastic left heart syndrome and trans-position of the great arteries are diagnosed prenatally versuswhen diagnosis of these two conditions is made only post-natally. Am J Cardiol 1999;83:1649e53.

[35] Bonnet D, Coltri A, Butera G, et al. Detection of transpositionof the great arteries in fetuses reduces neonatal morbidityand mortality. Circulation 1999;99:916e8.

[36] Vinals F, Ascenzo R, Poblete P, et al. Simple approach toprenatal diagnosis of transposition of the great arteries.Ultrasound Obstet Gynecol 2006;28:22e5.

[37] Yagel S, Arbel R, Anteby EY, et al. The three vessels andtrachea view (3VT) in fetal cardiac scanning. UltrasoundObstet Gynecol 2002;20:340e5.

[38] Yoo SJ, Golding F, Jaeggi E. Fetal cardiology: ventricularoutflow tract anomalies: so-called conotruncal anomalies.Informa Healthcare USA; 2009:305e27.

[39] Wilkinson JL, Cochrane AD, Karl TR. Congenital heart surgerynomenclature and database project: corrected (discordant)transposition of the great arteries (and related malforma-tions). Ann Thorac Surg 2000;69:S236e48.

[40] Donofrio MT. Images in cardiovascular medicine. Prematureclosure of the foramen ovale and ductus arteriosus in a fetuswith transposition of the great arteries. Circulation 2002;105:e65e6.

[41] Ferencz C, Neill CA, Boughman JA, et al. Congenital cardio-vascular malformations associated with chromosome abnor-malities: an epidemiologic study. J Pediatr 1989;114:79e86.

[42] Abuhamad A, Chaoui R. Genetic aspects of congenital heartdefetcs: a practical guide to fetal echocardiography: normaland abnormal hearts. Philadelphia: Lippincott Williams &Wilkins; 2010. P. 11e29.

[43] Devriendt K, Fryns JP, Mortier G, et al. The annual incidenceof DiGeorge/velocardiofacial syndrome. J Med Genet 1998;35:789e90.