\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[ngerman,english]{babel}
\usepackage{CJKutf8}



\usepackage{float}








\begin{document}

\title{Evaluation the added transverse planes in normal fetal upper mediastinum
by new color imaging technique in fetal echocardiography}



\author[1]{Yu Qi}%
\author[2]{Yu Wang}%
\author[2]{Xue Sun}%
\author[1]{huiyu Tang}%
\author[1]{Dong Wang}%
\author[2]{Ying Zhang}%
\affil[1]{Affiliation not available}%
\affil[2]{Shengjing Hospital of China Medical University}%


\vspace{-1em}



  
  \date{May 08, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Abstract Introduction: The current study aimed to assess the efficacy of
a new scanning procedure in fetal cardiac screening by 6 planes in the
upper mediastinum. Methods: This is a prospective study. 123 normal
fetuses without extracardiac abnormalities or CHD were enrolled in this
study totally. Two sonographers with similar experience were trained for
one month about how to obtain the added planes. Sonographer A used Color
Doppler combined with the radiant flow (Color-R-flow) while sonographer
B used high definition flow imaging combined with the radiant flow
(HD-R-flow) to display 6 planes in the upper mediastinum. The difference
between these two color modalities in subgroups of different fetal
positions (supine, prone, and lateral position) was also discussed.
Results: HD-R-flow has higher detection rates of the 6 planes than
Color-R-flow. The differences presenting for the left innominate vein
and azygos vein (LIV and AzV) view, bilateral subclavian arteries (BSA)
view, and the bilateral internal thoracic arteries (BITA) view were
significant (P\textless{}0.01). The results also demonstrated that
HD-R-flow showed significantly higher detection rates than the
Color-R-flow for the LIV and AzV view and the BITA view of the fetuses
in the supine and lateral position, and BSA view of fetuses in lateral
position. Conclusion: The current study introduced an enhanced scanning
procedure to assess vessels in the fetal upper mediastinum. A new
color-imaging technique was used to better show tiny vessels. This has
confirmed its value in showing a satisfactory detection rate for the 6
cardiac planes.%
\end{abstract}%



\sloppy


\textbf{Introduction}

Congenital heart disease (CHD), with an estimated incidence rate of 1\%
of newborns, remains to be the most common congenital malformations
leading to high morbidity and mortality of neonates {[}1-3{]}.
Echocardiography is the most effective modality to diagnose CHDs
prenatally, which assures proper perinatal management and thus improves
the outcome. Theoretically, most CHDs could be detected in the uterus by
an experienced fetal echocardiographer {[}4{]}. They are sensitive to
find subtle changes in morphology and hemodynamics in fetal heart and to
trace the clues to make an accurate diagnosis {[}5{]}. However, this
beyond the ability of most screening sonographers as it needs much
experience and expertise. A systematic scanning procedure with standard
cardiac planes is in need.

As recommended by ISUOG guidelines for fetal echocardiography, a series
of transverse planes is proposed in routine cardiac scans, including the
four-chamber view (4CV), bilateral outflow tracts views, and the
three-vessel trachea (3VT) view {[}6{]}. Previous reports had suggested
a high efficacy in detecting fetal CHDs using these transverse planes
{[}7-10{]}. However, some abnormalities in the fetal upper mediastinum
are apt to be missed by routine cardiac screenings. It is possible to
improve the detection of fetal CHDs by including more transverse cardiac
planes in addition to the existing recommended views.

Fetal great vessels could be visualized directly by gray-scale
ultrasonography. Color Doppler could undoubtedly enhance morphological
information and determine the blood direction. High-definition flow
(HD-flow) imaging is a special bidirectional Doppler technique that has
the potential benefits of better axial and lateral resolution, fewer
blooming artifacts, and improved sensitivity to display vessel perfusion
and blood flow continuity than traditional Color Doppler {[}11-13{]}.
Recently, the use of radiant flow (R-flow) imaging technique is a great
improvement in fetal cardiac imaging. By specific algorithm, the index
of erythrocyte density in a certain area is converted into height index
and then superimposed on the initial coding of color or HD-flow. The
flow is then displayed in a sense of depth, resembling a
three-dimensional visual effect. Besides, the use of Color
Doppler/HD-flow together with the R-flow technique could apparently
reduce color overflow and thus show vessels with sharp edges.

The current study aimed to evaluate the efficacy of a detailed procedure
exploring vessels in the fetal upper mediastinum. Two color imaging
modalities were used to compare their performance in the investigation
of these planes.

\textbf{Materials and Methods}

Study population

The study population was randomly selected in the pregnant women
presented to our center from July 2018 to December 2019. Fetuses with
confirmed CHD or extracardiac abnormalities were excluded. Mothers with
gestational anemia, diabetes, hypertension, and other high-risk factors
were also excluded. All fetuses involved were singletons. In total, 123
pregnant women were enrolled in this study. Maternal gestation age
ranged from 20 to 37 weeks. Informed consent was obtained from each
patient and the study was approved by the Ethics Committee of Shengjing
Hospital of China Medical University. All cases underwent a month
postnatal echocardiography follow-up.

Ultrasonography technique

An ultrasound system (Voluson E10, GE Healthcare, Kretztechnik, Zipf,
Austria), equipped with a 2 to 9 MHz transabdominal transducer was used
in this study. Each patient was scanned by two screening sonographers
with one year of experience, independently, using gray-scale ultrasound
and different color techniques. They were both adept at the traditional
procedures of fetal cardiac transverse scanning using the 4CV, the left
and right outflow tracts view, and the 3VT view. Then, they were both
trained for three months to become familiar with scanning the added
planes included in the current study. The specific scanning procedures
are achieved by continuously moving the sound beam cephalad along the
vertical axis of the fetal thorax. When scanning the root of the great
arteries, the sound beam sections through the long-axis of the ductus
arteriosus and the right pulmonary artery, together with the short-axis
of the aorta and superior vena cava. It is the 3VV. Slight rotating the
sound beam to the left, the bifurcation of the pulmonary artery should
be demonstrated to show the normal pulmonary artery branching patterns.
It is the branch of pulmonary artery bifurcation (BPAB) view. When the
beam sections through the arch, the ductus arteriosus, and their
convergence, the 3VT view is obtained. When continuing elevating the
sound beam, it demonstrates that the superior vena cava is joined by
both the left innominate vein and the posteroanterior drainage of the
azygos vein. When the beam is turned further cephalad, it sections
across the transverse aortic arch forming a sausage-like structure
{[}14{]}. The origin of bilateral subclavian arteries (BSA) could be
identified in this plane. Scanning around the BSA, the origin of
bilateral internal thoracic arteries (BITA) from the ipsilateral
subclavian artery can be demonstrated {[}15{]}. The related anatomical
structures that should be recognized in each plane were listed in Table
1.

For both sonographers involved in the study, the first recognized
anatomical structures (including the course of the great vessels) by
gray-scale ultrasound. Then, different color-imaging techniques were
used to assess the vessels in detail, including the course and flow
direction. For sonographer A, he used Color Doppler combined with the
radiant flow (Color-R-flow modality) to show the vessels if needed,
while HD-flow combined with the radiant flow (HD-R-flow modality) was
used by sonographer B when scanning these planes. For both modalities,
the scale was set to 20-30 cm/s and 40-50 cm/s when showing the veins
and arteries respectively. The number of planes visualized was recorded
for each sonographer to make a comparison.

As cardiac apex orientation might pose some effects on the detection of
the cardiac views, we also made comparisons among different fetal
positions when necessary. Three subgroups were made according to the
supine position (cardiac apical pointing to 10-2 o'clock), the prone
position (cardiac apical pointing to 4-8 o'clock), and the lateral
position (cardiac apical pointing to 2-4 and 8-10 o'clock).

Statistical analysis

The detection rates for the two modalities were compared via McNemar
analysis. \emph{P} ~-values\textless{}0.05 were considered statistically
significant. All statistical analyses were performed using commercially
available software (SPSS, release 17.0).

\textbf{Results}

The feasibility of the algorithm was studied in 123 fetuses. The mean GA
was 26 \selectlanguage{ngerman}± 2.3 weeks and the mean BMI was 25 ± 3.6
kg/m\textsuperscript{2}. In total, 6 cardiac planes were included in the
current study. The detection rate for each plane is presented in Table
2. The 3VV and 3VT view are in high visualization rate, varying from
88.62\% to 97.56\%, for the two color imaging modalities. HD-R-flow
modality showed a higher detection rate for all the 6 planes than the
Color-R-flow method, with significance presenting for the left
innominate and azygos vein (LIV and AzV) view (71.54\% vs. 35.77\%),
bilateral subclavian arteries (BSA) view (85.37\% vs. 60.16\%), and the
bilateral internal thoracic arteries (BITA) view (75.61\% vs. 50.41\%)
(Figure).

As Doppler shift could be affected by the angle between the sound beam
and the flow direction, we speculated that the detection of these
cardiac planes would also be affected by different fetal positions.
Since the differences of detection rates of 3VV, BPAB and 3VT views were
of no significance, the affection of the fetal position was not under
discussion. Then, fetuses were sub-grouped according to different
cardiac orientations and comparisons were made between the two
color-imaging modalities for the detection of the last three planes. The
results demonstrated that HD-R-flow modality showed a significantly
higher detection rate than the Color-R-flow modality for the LIV and AzV
view (Supine and Lateral position), BSA view (Lateral position), and the
BITA view (Supine and Lateral position). However, for the prone
position, the detection for each plane was very low and no significance
was demonstrated for each of the two modalities (Table 3).

\textbf{Discussion}

The detection of CHD remains a great challenge during routine obstetric
screenings. It is realized that some severe CHDs could be identified by
fetal echocardiography early in the 1990s {[}16-17{]}. Initially, only
the 4CV was used to determine whether a CHD was in existence in the
circumstance of asymmetrical chambers, large-in-sized VSD/AVSD, or
space-occupying lesions {[}18-20{]}. Obvious limitations had been shown
for this modality as it could only identify anomalies at the atrial and
ventricular level. The situation had been improved impressively when the
left and right outflow tract views were included in the routine
diagnostic procedures besides the 4CV, which was supported by the fact
of a significantly higher detection rate for conotruncal anomalies
{[}19, 21-23{]}.

Recently, the new fetal echocardiography guideline had shown its
advantage in detecting more than 90\% CHDs in the uterus, as documented
by several teams and regional studies. The addition of the 3VT view
apparently contributes to the improved performance in this new guideline
{[}24{]}. It was a great development to evaluate fetal great arteries
anatomy as the characteristic sonograms in this specific plane are apt
to recognize by general examiners. The ductus arteriosus, aortic arch,
and their convergence in a ``V'' configuration could be visualized on
the left side of the trachea. In fact, most arch anomalies could be
demonstrated by this plane, such as double aortic arch, right aortic
arch, aberrant left/right subclavian artery, etc {[}25-26{]}. We proved
a very high detection rate for this plane by screening the sonographers
of one-year experience.

Unfortunately, many screening sonographers concern much on the 3VT view
while anatomical structures between the level of the outflow tracts and
3VT planes are not noticed. When gradually elevating the sound beam from
the outflow tracts views, it firstly sections through the pulmonary
trunk and its branches, and then the convergence of the arch and the
ductus arteriosus. We previously reported that it is crucial to
searching around the 3VV to exclude malformations associated with the
aortic origin of the left/right pulmonary artery {[}27{]}. Also, in the
case of the pulmonary sling, the abnormal origin together with the
retroesophageal course of the left pulmonary artery from the right
pulmonary artery could only be shown at the 3VV while it could not be
shown at the 3VT view. We added these 2 cardiac planes in the current
study to explore the feasibility in routine screenings. To our point,
the 3VV is relatively easy to obtain while it is very difficult to show
the BPAB view. A learning curve is needed for scanning. The pulmonary
branching patterns could better be identified by gray-scale ultrasound
when searching along the pulmonary trunk, as far as our experience is
concerned. Though the addition of color imaging helps to determine the
flow direction of the vessels, it does not seem to help much in
improving the detection of the branching when searching along the
pulmonary trunk.

However, color techniques are necessary to investigate small or tiny
vessels, as the vascular wall is too thin to be visualized by gray-scale
ultrasound. Color Doppler has long been used in echocardiography while
it cannot show vessels with a low velocity with a good effect. Doppler
shift can be immensely affected by the angle of the sound beam which
contributes to the low sensitivity in showing small vessels with low
velocity. The introduction of HD-flow is a great innovation in fetal
color imaging. It shows a higher sensitivity to display blood flow in
better perfusion than the traditional Color Doppler technique
{[}11-13{]}. However, excessively higher sensitivity may lead to color
overflow and thus decrease the spatial resolution of the vessels. The
R-flow technique could display color flow in a three-dimensional effect
by adding an algorithm upon initially Color/HD-flow. When using
HD-R-flow, the vessels can then be displayed with both high sensitivity
and high resolution with a sharp edge.

Technical renovations can further promote the launch of a new and
improved protocol for fetal cardiac scanning. Aorta, the pulmonary
artery, and the superior vena cava are the three great vessels which
should be scanned according to the current guidelines {[}6{]}. Other
smaller vessels are existing in the upper mediastinum, such as the
tributaries of superior vena cava (SVC), branches of the aortic arch
(i.e. left/right carotid artery, left/right subclavian artery), and the
internal thoracic artery. We tried to explore these vessels in routine
cardiac scans and thus to screen more malformations in potential. The
application of the new color technique makes it possible to approach the
skill for the detection of these additional vessels with small size and
low-velocity.

Three planes above the level of 3VT view were added in the current
study. Anatomically, the right innominate vein goes down straight and
continues to be the SVC, when the LIV joins it. AzV is a small-sized
vessel that serves as a little tributary of SVC. It is hard to be
identified using Color Doppler in the past while it is relatively easy
to show in many fetuses when scanned by HD-flow. In the case of
supracardiac anomalous pulmonary venous connect, the flow of pulmonary
veins may drain into the LIV via the vertical vein. The examiner may
find the indirect sign of a dilated LIV and thus to trace its origin to
make a diagnosis {[}28{]}. In other cases, when the LIV is not shown on
this plane, the examiner should consider the possibility of a left SVC.
If a dilated AzV is in visualization in this plane, the possibility of
an interrupted inferior vena cava might be in consideration {[}29{]}.

For the BSA plane, it is useful to make the diagnosis of an aberrant
left/right subclavian artery, in which the bilateral subclavian arteries
arise from almost the same position at the proximal descending aorta.
This is very different from normal fetuses, in which the origins of the
left and right subclavian artery were located at the two ends of the
arch. At 3VT view, AzV sometimes may be misrecognized as an aberrant
right subclavian artery. The scanning of the BSA plane helps to make a
differential diagnosis. In addition, the size of the thymus could be
assessed by the BITA plane since it is surrounded by BITA. A small-sized
or disappeared thymus at this plane may suggest the possibility of
Digeorge Syndrome {[}30{]}.

At last, we want to comment on the efficacy of the detailed scanning
procedure performed by the screening sonographers. HD-R-flow apparently
showed a better performance than color-R-flow in showing small vessels
in the three planes above the 3VT level. The difference between the two
color-imaging modalities may be related to different degrees of
influence by Doppler shift as the difference presents only for fetuses
with apical/lateral insonation. BRAVO et al. reported a higher detection
rate for BSA and BITA plane than our results {[}31{]}. An
echocardiographer apparently has much more experience than a screening
sonographer with only one-year experience. However, we can expect a long
term training session may improve the detection of these added planes.
For all the 6 planes involved in the current study, the detection rate
is above 70\%, suggesting a potential wide clinical usage in the future.

\textbf{Study limitation}

The study was limited in that it was relatively small research and did
not recruit CHD fetuses. We expect to carry out a multi-center study in
a normal screening population to evaluate the sensitivity and
specificity of this detailed scanning procedure in cardiac screening.
Besides, to our acknowledgment, the study about the R-flow on fetal
echocardiography is rare. We expect the advanced application of R-flow
on the prenatal diagnosis of the fetal heart.

\textbf{Conclusions}

The current study introduced an enhanced scanning procedure to assess
vessels in the fetal upper mediastinum. New color-imaging techniques
were used to better show tiny vessels with low-velocity. A short-term
training session made it possible for the screening sonographers to
become familiar with the new scanning procedure; this has confirmed its
value in showing a satisfactory detection rate for the 6 cardiac planes.

\textbf{Acknowledgements}

We thank for all the medical specialists who helped collecting the
experimental data.

\textbf{Consent for publication}

Not applicable.

\textbf{Competing interests}

The authors declare that they have no competing interests.

\textbf{References:}

1. Hoffman JI, Kaplan S: The incidence of congenital heart disease. J Am
Coll Cardiol 2002:39(12):1890-1900.

2. Massaro AN, El-Dib M, Glass P, et al: Factors associated with adverse
neurodevelopmental outcomes in infants with congenital heart disease.
Brain Dev 2008:30(7):437-446.

3. Cuneo BF, Curran LF, Davis N, et al: Trends in prenatal diagnosis of
critical cardiac defects in an integrated obstetric and pediatric
cardiac imaging center. J Perinatol 2004:24(11):674-678.

4. Ayres NA: Advances in fetal echocardiography. Tex Heart Inst J 1997:
24(4):250-259.

5. Zhang Y, Cai AL, Ren WD, et al: Identification of fetal cardiac
anatomy and hemodynamics: a novel enhanced screening protocol. BMC
Pregnancy Childbirth 2016:16:145.

6. Carvalho JS, Allan LD, Chaoui R, et al: ISUOG practice guidelines
(updated): sonographic screening examination of the fetal heart.
Ultrasound Obstet Gynecol 2013: 41(3): 348-359.

7. Bravo C, Gámez F, Pérez R, et al: Fetal Aortic Arch Anomalies: Key
Sonographic Views for Their Differential Diagnosis and Clinical
Implications Using the Cardiovascular System Sonographic Evaluation
Protocol {[}published online ahead of print Jun 35, 2016{]}. J
Ultrasound Med 2016:35(2):237-251.

8. Yang ZJ, Pei QY, Li YT, et al: Continuous transverse scanning of the
fetal heart using a cross-sectional image database of common fetal
congenital heart deformities. Taiwan J Obstet Gynecol
2016:55(2):176-182.

9. Weissmann-Brenner A, Zajicek M, Weisz B, et al: Feasibility of
detection of the 3-vessel and trachea view using 3-dimensional
sonographic volumes. J Ultrasound Med 2014:33(4):681-685.

10. Li H, Wei J, Ma Y, et al: Prenatal diagnosis of congenital fetal
heart abnormalities and clinical analysis. J Zhejiang Univ Sci B
2005:6(9):903-906.

11. He YH, Liu K, Gu XY, et al: The application of high definition flow
imaging in fetal hemodynamics. Clin Exp Obstet Gynecol 2015:
42(1):11-17.

12. Hata T, Dai SY, Inubashiri E, et al: Four-dimensional sonography
with B-flow imaging and spatiotemporal image correlation for
visualization of the fetal heart. J Clin Ultrasound 2008: 36(4):204-207.

13. Rizzo G, Pietrolucci ME, Aiello E, et al: Are there any differences
in three-dimensional placental vascular indices obtained using
conventional power Doppler and high-definition flow imaging? J Matern
Fetal Neonatal Med 2012: 25(9):1664-1667.

14. Yoo SJ, Min JY, Lee YH, et al: Fetal sonographic diagnosis of aortic
arch anomalies. Ultrasound Obstet Gynecol 2003: 22(5):535-546.

15. Bravo C, Gámez F, Pérez R, et al: Fetal Aortic Arch Anomalies: Key
Sonographic Views for Their Differential Diagnosis and Clinical
Implications Using the Cardiovascular System Sonographic Evaluation
Protocol. J Ultrasound Med 2016:35(2):237-251.

16. Copel JA, Pilu G, Green J, et al: Fetal echocardiographic screening
for congenital heart disease: the importance of the four-chamber view.
Am J Obstet Gynecol 1987: 157(3):648-655.

17. Allan LD, Crawford DC, Chita SK, et al: Prenatal screening for
congenital heart disease. Br Med J (Clin Res Ed) 1986:
292(6537):1717-1719.

18. Shi C, Song L, Li Y, et al: Value of four-chamber view of the fetal
echocardiography for the prenatal diagnosis of congenital heart dise.
Zhonghua Fu Chan Ke Za Zhi 2002:37(7):385-387.

19. Sharland G. Routine fetal cardiac screening: what are we doing and
what should we do? Prenat Diag 2004:24(13): 1123-1129.

20. Sharland GK, Allan LD. Screening for congenital heart disease
prenatally. Results of a 2 1/2-year study in the South East Thames
Region. Br J Obstet Gynaecol 1992: 99(3): 220-225.

21. Hernandez-Andrade E, Patwardhan M, Cruz-Lemini M, et al: Early
Evaluation of the Fetal Heart. Fetal Diagn Ther 2017:42(3):161-173.

22. Kusajima K, Hoashi T, Kagisaki K, et al: Reoperative double
ventricular outflow tract reconstruction in grown-up congenital heart
disease patients with conotruncal anomalies. Gen Thorac Cardiovasc Surg
2015:63(11):595-600.

23. Quartermain MD, Glatz AC, Goldberg DJ, et al: Pulmonary outflow
tract obstruction in fetuses with complex congenital heart disease:
predicting the need for neonatal intervention. Ultrasound Obstet Gynecol
2013:41(1):47-53.

24. Viñals F, Heredia F, Giuliano A. The role of the three vessels and
trachea view (3VT) in the diagnosis of congenital heart defects.
Ultrasound Obstet Gynecol 2003:22(4):358-367.

25. Wang Y, Fan M, Siddiqui FA, et al: Strategies for Accurate Diagnosis
of Fetal Aortic Arch Anomalies: Benefits of Three-Dimensional Sonography
With Spatiotemporal Image Correlation and a Novel Algorithm for Volume
Analysis. J Am Soc Echocardiogr 2018:31(11):1238-1251.

26. Yagel S, Arbel R, Anteby EY, et al: The three vessels and trachea
view (3VT) in fetal cardiac scanning. Ultrasound Obstet Gynecol
2002:20(4):340-345.

27. Ma J, Zhang Y, Wang Y, et al: Prenatal two-and three-dimensional
echocardiographic diagnosis of anomalous origin of one pulmonary artery
from the ascending aorta: Case report and literature review. J Clin
Ultrasound 2020:23.

28. Sun X, Zhang Y, Fan M, et al: Role of four-dimensional
echocardiography with high-definition flow imaging and spatiotemporal
image correlation in detecting fetal pulmonary veins. Echocardiography
2017:34(6):906-914.

29. Xu Q, Sun HX, Xie JS, et al: Zhonghua Fu Chan Ke Za Zhi
2018:53(3):149-154.

30. Tramontana A, Hartmann B, Hafner E. DiGeorge syndrome chromosome
region deletion and duplication: Prenatal genotype-phenotype variability
in fetal ultrasound and MRI. Prenat Diagn 2019:39(13):1225-1234.

31. Bravo C, Gámez F, Pérez R, et al: Fetal Aortic Arch Anomalies: Key
Sonographic Views for Their Differential Diagnosis and Clinical
Implications Using the Cardiovascular System Sonographic Evaluation
Protocol. J Ultrasound Med 2016:35(2):237-251.



\textbf{Tables:}

\textbf{Table 1} Anatomical structures recognized at each view of the
added planes in the current study\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
Cardiac planes & Anatomical structures\tabularnewline
\midrule
\endhead
3VV & The long-axis of MPA, RPA and DA, the short-axis of AAO, SVC and
DAO.\tabularnewline
BPAB & MPA, the bifurcation into the RPA and LPA and the short-axis of
AAO, DAO and SVC.\tabularnewline
3VT & The V-shape formed by DA and AAO, the short-axis of SVC and DAO,
trachea.\tabularnewline
LIV and AzV & SVC is joined by both the LIV and the posteroanterior
drainage of AzV.\tabularnewline
BSA & The S-shaped formed by BSA.\tabularnewline
BITA & The thymus is located in the middle of the chest and laterally by
BITA.\tabularnewline
\bottomrule
\end{longtable}

3VT, three-vessel trachea view; 3VV, three-vessel view; AAO, aortic
arch; AzV: azygos vein; BITA: bilateral internal thoracic arteries;
BPAB: branch pulmonary artery bifurcation; BSA: bilateral subclavian
arteries; DA, ductus arteriosus; DAO, descending aorta; LIV: left
innominate vein; SVC, superior vena cava.

\textbf{Table 2 The detection rates for six cardiac planes in normal
fetal upper mediastinum using two color-imaging modalities}\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
\begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
Cardiac planes\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
HD-Radiant flow n (\%)\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
Color-Radiant flow n (\%)\strut
\end{minipage} & \begin{minipage}[b]{0.24\columnwidth}\raggedright\strut
P-value\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
3VV\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
111(90.24)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
109(88.62)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.500\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
BPAB\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
87(70.73)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
84(68.29)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
0.250\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
3VT\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
120(97.56)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
119(96.75)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
1.000\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
LIV and AzV\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
88(71.54)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
44(35.77)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}0.01(0.000)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
BSA\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
105(85.37)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
74(60.16)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}0.01(0.000)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
BITA\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
93(75.61)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
62(50.41)\strut
\end{minipage} & \begin{minipage}[t]{0.22\columnwidth}\raggedright\strut
\textless{}0.01(0.000)\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

3VT, three-vessel trachea view; 3VV, three-vessel view; AzV, azygos
vein; BITA, bilateral internal thoracic artery; BPAB, Branch pulmonary
artery bifurcation; BSA, bilateral subclavian artery; LIV, left
innominate vein.

\textbf{Table 3 The detection of the three cardiac planes above the
three-vessel trachea view according to different fetal positions}\selectlanguage{english}
\begin{longtable}[]{@{}llllllllllll@{}}
\toprule
\begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Cardiac planes\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Supine\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Supine\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Supine\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Supine\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Lateral\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Lateral\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Lateral\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Prone\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Prone\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Prone\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Prone\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
HDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
CDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
P-value\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
HDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
HDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
CDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
P-value\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
P-value\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
HDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
CDFI n (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
P-value\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
LIV and AzV view\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
26 (86.67)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
11 (36.67)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
56 (70.89)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
56 (70.89)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
31 (39.24)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
6 (42.86)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
2 (14.29)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
0.125\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
BSA view\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
27 (90.00)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
23 (76.67)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
0.125\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
72 (91.14)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
72 (91.14)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
47 (59.49)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
6 (42.86)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
4 (28.57)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
0.500\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
BITA view\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
27 (90.00)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
21 (70.00)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.031)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
58 (73.42)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
58 (73.42)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
35 (44.30)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
\textless{}0.05 (0.000)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
8 (57.14)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
6 (42.86)\strut
\end{minipage} & \begin{minipage}[t]{0.08\columnwidth}\raggedright\strut
0.500\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

Supine: Indicates fetal cardiac orientation is between 10-2 o'clock

Lateral: Indicates fetal cardiac orientation is between 2-4 and 8-10
o'clock

Prone: Indicates fetal cardiac orientation is between 4-8 o'clock

AzV, azygos vein; BITA: bilateral internal thoracic artery; BSA,
bilateral subclavian artery; LIV, left innominate vein.

\textbf{Figure legends:}

The added planes acquired by Color-R-flow and HD-R-flow in a fetus of 25
week. A. three-vessel view (3VV), B. branch pulmonary artery bifurcation
view (BPAB), C. three-vessel trachea view (3VT), D. the left innominate
vein and azygos vein view, E. the bilateral subclavian arteries view, F.
the bilateral internal thoracic arteries view.

AA, aortic arch; AO, ascending aorta; AzV, azygos vein; DA, ductus
arteriosus; DAO, descending aorta; L-ITA, left internal thoracic artery;
LIV, left innominate vein; LPA, left pulmonary artery; LSA, left
subclavian artery; MPA, main pulmonary artery; R-ITA, right internal
thoracic artery; RPA, right pulmonary artery; RSA, right subclavian
artery; SVC, superior vena cava; T, trachea.

\textbf{Abbreviations:}

3VT, three-vessel trachea; 3VV, three-vessel vein; 4CV, four chamber
view; Azy, azygos vein; BITA, bilateral internal thoracic arteries;
BPAB, branch pulmonary artery bifurcation; BSA, bilateral subclavian
arteries; Color-R-flow, Color Doppler combined with radiant flow; CHD,
congenital heart disease; HD-flow, high definition flow imaging;
HD-R-flow; high definition flow imaging combined with radiant flow; LIV,
left innominate vein; R-flow, radiant flow; SVC, superior vena cava.

\textbf{Hosted file}

\verb`\begin{CJK}{UTF8}{gbsn}投稿用图.\end{CJK}\selectlanguage{english}eps`  available at \url{https://authorea.com/users/355685/articles/478823-evaluation-the-added-transverse-planes-in-normal-fetal-upper-mediastinum-by-new-color-imaging-technique-in-fetal-echocardiography}

\selectlanguage{english}
\FloatBarrier
\end{document}

