AJR 2000; 175:1403-1407
© American Roentgen Ray Society
Three-Dimensional CT of Congenital Esophageal Atresia and Distal Tracheoesophageal Fistula in Neonates
Preliminary Results
Suat Fitoz1,
Çetin Atasoy1,
Aydin Yagmurlu2,
Serdar Akyar1,
Ay
e Erden1 and
Hüseyin Dindar2
1
Department of Radiology, University of Ankara, School of Medicine, Talatpasa
Bulvari, 06100 Sihhiye/Ankara, Turkey.
2
Department of Pediatric Surgery, University of Ankara, School of Medicine,
06100 Dikimevi/Ankara, Turkey.
Received March 1, 2000;
accepted after revision May 1, 2000.
Address correspondence to S. Fitoz, Atatürk
Sitesi, Hayri Cecen S., Ali Haydar Sanli Apt., 29/12, 06450 Or-An, Ankara,
Turkey.
Abstract
OBJECTIVE. Radiography was traditionally used in the preoperative
treatment of neonates with tracheoesophageal atresia and tracheoesophageal
fistula. The aim of this study was to assess the potential use of
three-dimensional CT in the evaluation of this complex congenital
malformation.
CONCLUSION. Three-dimensional CT coupled with reformations in the
three orthogonal planes may have a complementary diagnostic role in congenital
esophageal atresia.
Introduction
Esophageal atresia, with or without tracheoesophageal fistula, is the most
important congenital malformation of the esophagus. The reported overall
incidence of esophageal atresia and tracheo-esophageal fistula is
approximately one in 3000-4500 live births
[1]. Patients usually present
with inability to swallow food and saliva and with respiratory distress due to
aspiration. Prognosis depends on the severity of accompanying malformations
and ventilatory dependence before surgery. The anatomy of esophageal atresia,
with or without fistula, should be shown before surgery. Frontal and lateral
chest radiography, the first diagnostic steps in patients presenting with
symptoms suggestive of tracheoesophageal fistulas, confirms the location of
the catheter in the blind esophageal pouch and shows the pouch length.
Radiographic contrast studies can also be used to look for the rare proximal
fistula, but patients run the risk of pulmonary aspiration, compounding
existing lung damage [2].
To show the anomalies of the tracheobronchial tree and locate the orifice
of the distal fistula in patients with esophageal atresia, some researchers
recommend the routine use of bronchoscopy just before the corrective operation
[3]. However, bronchoscopy has
well-known limitations in neonates. Flexible bronchoscopes are associated with
problems of ventilation, which often poses a time limit of 30-45 sec on this
procedure. Rigid bronchoscopy, which is often performed in the operating
theater, requires general anesthesia. Both flexible and rigid bronchoscopy may
lead to several complications including hypoxia, laryngospasm, pneumothorax,
and airway edema and bleeding
[4,
5].
On the other hand, three-dimensional (3D) imaging including shaded-surface
display (SSD) and recently developed virtual bronchoscopy is a noninvasive
technique that provides realistic 3D views of the tracheobronchial tree
[6]. Three-dimensional imaging
of the tracheobronchial system is well established in adults, but experience
with pediatric patients is limited. To our knowledge, 3D helical CT has not
been used to show the abnormal anatomy in children with esophageal atresia and
tracheoesophageal fistulas. Our purpose was to describe the potential use of
this technique in neonates with esophageal atresia and tracheoesophageal
fistulas.
Subjects and Methods
Eight neonates, three boys and five girls, all with esophageal atresia and
tracheoesophageal fistulas, were included in the study. Patients' birth
weights ranged from 1250 to 2720 g (mean, 2170 g). Mean gestational age was
34.5 weeks (range, 32-39 weeks). The initial diagnosis was made by clinical
symptoms and radiographs showing the catheter inserted into the blind-ended
esophageal pouch. Before CT the proximal pouch was suctioned with an
aspirating catheter, and oxygenation was provided through a nasal cannula
during the procedure. To avoid respiratory distress, sedation was not given.
Body straps were used to immobilize patients and reduce motion artifacts.
After CT all neonates underwent surgery, and CT findings were correlated with
surgical results.
Helical CT data were acquired with a HiSpeed CT Scanner (General Electric
Medical Systems, Milwaukee, WI). Helical CT with 3-mm collimation was
performed from the level of the larynx to the domes of the diaphragm. A pitch
of 1:1 was selected to reduce the stairstep artifacts. The technical factors
were 80 kVp and 100 mA, with a calculated center body dose of 0.57 mGy. The
scanning time ranged from 8 to 21 sec. Images were reconstructed in the axial
plane at 1.5-mm intervals with a standard reconstruction algorithm. The
display field of view was reduced to its minimum level of 9.6 cm to provide
the highest possible in-plane resolution. The CT data were transferred to an
independent workstation (Advantage Windows; General Electric Medical Systems),
which consisted of a Sparc 20 computer (Sun Microsystems, Mountain View, CA).
We generated SSD models of the tracheobronchial system with a lower threshold
of -1000 H and an upper threshold of -500 H, and we created endoluminal
images, using the Windows Navigator system (General Electric Medical Systems).
A four quadrant-divided workstation screen offered a SSD, a transaxial view, a
multiplanar reconstruction coronal view, and a multiplanar reconstruction
sagittal view. The location of the virtual endoscope, which has the ability to
rotate in all directions within the 3D space, was simultaneously identified in
each quadrant. As the cursor moved, the endoscopic view was correlated with
its 3D coordinates to determine the cursor's position and to identify any
motion artifacts. Total image processing time was 30-45 min per patient.
Results
In one patient, motion artifacts due to excessive dyspnea and cough
prevented 3D demonstration of the proximal pouch and distal fistula, which
could be located only on the axial images. In seven of the remaining eight
patients, SSD and virtual bronchoscopic images could satisfactorily show the
anatomic features of the anomaly. In these patients, the tracheae and
bronchial systems including the major lobe bronchi, the proximal pouches, and
the levels of the distal fistulas were shown clearly. In most patients zigzag
artifacts occurred because of motion and respiration; however, they did not
interfere with visualization of the orifice of the distal fistula (Fig.
1A,1B,1C).
In one patient the connection of the distal fistula with the trachea could not
be visualized on SSD images; however, the orifice of the fistula was
inconspicuously depicted on virtual bronchoscopy (Fig.
2A,2B).
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Fig. 2A. —4-day-old dyspneic female neonate with aspiration pneumonia.
Shaded-surface—display image of mediastinum from left lateral aspect
(after left lung was removed from image) reveals significant dilatation of
proximal esophageal pouch (E). Note narrow calibrated distal esophageal
segment (arrow). Tracheal connection cannot be seen because of
peristalsis.
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In seven patients in whom 3D imaging was successful, the lower fistula was
shown to open into the trachea within 1 cm of the carina (Figs.
2A,2B,3A,3B,3C,4A,4B,5A,5B).
The air-containing proximal pouch was also shown in these patients (Figs.
2A,2B,3A,3B,3C,4A,4B,5A,5B).
Two cases were correctly classified as long-gap esophageal atresia because the
distance from the lowermost edge of the proximal pouch to the distal fistula
exceeded 3 cm, as confirmed surgically
(Fig. 4A). In two patients
tracheomalacia was noted as an associated abnormality (Figs.
4A and
5A), which was also confirmed
at surgery.
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Fig. 3A. —34-week-old preterm female infant at 4th day after birth who
presented with inability to swallow. Three-dimensional surface-rendered
anteroinferior image depicts complex anatomic malformation. Note proximal
atretic portion of esophagus (black arrow) and distal segment arising
from carina (white arrow).
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Fig. 3B. —34-week-old preterm female infant at 4th day after birth who
presented with inability to swallow. Three-dimensional surface-rendered image
from posterior external view of trachea and large airways shows lesion better
defined as fistulous connection with distal esophagus at posterior wall of
carina.
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Fig. 3C. —34-week-old preterm female infant at 4th day after birth who
presented with inability to swallow. Virtual bronchoscopic image of carina
clearly shows orifice of fistula (thick arrow) posterior to orifices
of main bronchi (thin arrows).
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Fig. 4A. —33-week-old premature female infant with feeding difficulty.
Shaded-surface—display image shows long gap between proximal pouch
(double arrowhead) and distal fistula (thick arrow). Note
distortion caused by catheter inserted into malacic segment of trachea. Thin
arrow indicates tip of catheter.
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Fig. 5A. —33-week-old premature male infant with esophageal atresia.
Shaded-surface—display image clearly delineates anatomy of proximal
pouch and shows fistula between carina and distal esophagus (black
arrow). Note also proximal tracheomalacia (thin white arrows)
and artifactual interruption of left main bronchus (thick white
arrow).
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Discussion
Esophageal atresia is one of the most challenging congenital anomalies for
the pediatric surgeon because of its high morbidity and mortality. In healthy
neonates the ideal treatment consists of division and closure of the fistula
with primary repair of the atresia, but a staged repair is frequently
necessary in those with low birth weight, severe respiratory distress, a long
gap between the proximal and distal esophagus, or severe accompanying
anomalies [7]. Because the
surgical approach depends on a correct evaluation of the tracheobronchial tree
and the distance between the proximal pouch and distal fistula, the anatomy of
the esophageal atresia, with or without a tracheoesophageal fistula, should be
shown before surgery [8].
Frontal and lateral chest radiographs may give an estimate of the pouch length
by showing the catheter inserted into the blind esophageal pouch. An important
drawback of radiography is its inability to show the distal esophagus in most
patients. Some researchers recommend combining endoscopy and radiography to
examine the distal esophagus and the developmental status of pouches in
long-gap esophageal atresia [7,
8]. But this technique is
highly invasive and suffers from a low resolution especially with rigid
bronchoscopes [4].
Because helical CT allows volume acquisition, helical CT has promoted a
renewed interest in 3D reconstruction of the tracheobronchial tree
[6,
9,
10]. Although its advantages
in adults are well known, there is only one report regarding its use in
children [6] and, to our
knowledge, none in neonates.
Several factors peculiar to this age group preclude optimal 3D imaging of
the airway. The small size of the airway naturally renders images poor in
resolution, but the size may be compensated for by selecting small fields of
view, as was done in our study.
The cardiac and respiratory motion results in zigzag artifacts in the walls
of the airway when reconstructing in virtual bronchoscopy
[6]. Referring to coronal and
sagittal reformations may identify these artifacts. Though a potential
simulator of mucosal or submucosal lesions, these artifacts were not of great
concern in this study, and they did not interfere with visualization of the
fistula orifice in any patient. As in the tracheobronchial system, the large
contrast gradient between the wall and air-filled lumen of esophagus enabled
3D reconstruction of the proximal pouch and the distal segment. Thus 3D
imaging of the anomaly and distance measurements between esophageal segments,
which provide crucial information for planning surgery, could easily be made.
SSD techniques select arbitrarily a threshold level and have the potential to
hide or create discontinuities in walls or to change apparent diameters of
lumens [11]. Considering this
drawback, we correlated simulation-based measurements with axial and
multiplanar reconstruction images to avoid erroneous results.
The site of entry of the lower fistula into the tracheobronchial tree is
variable; it may enter at any point from 2 cm above the carina to the proximal
centimeter of either bronchus. The most common site, however, is 0.5-1 cm
above the carina [12]. Our
virtual bronchoscopic images noninvasively revealed the orifice of the fistula
in seven patients, which was confirmed surgically thereafter.
Although based on a limited number of patients, our findings suggest that
CT may have a complementary diagnostic role in congenital esophageal atresia.
Although 3D CT did not provide information beyond what was already obtained by
standard axial images, SSD images facilitated appreciation of complex anatomic
features of the anomaly by the surgeon, enabling a better orientation before
surgery.
Our patient group included only the neonates with proximal esophageal
atresia and distal tracheoesophageal fistulas, which form most of the
congenital esophageal atresias. This group of neonates is best suited for 3D
CT examination of the anomaly because of the large contrast gradient provided
by the air-filled lumen of the distal segment. However, in those types of
esophageal atresia in which the distal lumen is devoid of air, the technique
may not be as successful. This study involving the neonatal group should be
followed by more extensive research on a larger series of patients to evaluate
the sensitivity and specificity of the method, to optimize the technical
parameters, and to eliminate or reduce artifacts.
References
-
Guiney EJ. Oesophageal atresia and tracheo-oesophageal fistula. In:
Puri P, ed. Newborn surgery, 1st ed. Oxford, United
Kingdom: Butterworth-Heinemann, 1996:227
-237
-
Mellor DJ, Desparment J, Braude BM. Use of flexible, illuminated
stylet to demonstrate the proximal esophageal pouch in surgical repair of
esophageal atresia. Pediatr Surg Int
1999;15:296[Medline]
-
Usui N, Kamata S, Ishikawa S, et al. Anomalies of the
tracheobronchial tree in patients with esophageal atresia. J
Pediatr Surg 1996;31:258
-262[Medline]
-
Nagaraj HS. Bronchoscopy in newborns. In: Puri P, ed.
Newborn surgery, 1st ed. Oxford, United Kingdom:
Butterworth-Heinemann, 1996:221
-223
-
Slonim AD, Ognibene FP. Amnestic agents in pediatric bronchoscopy.
Chest
1999;116:1802
-1808[Abstract/Free Full Text]
-
Konen E, Katz M, Rozenman J, Ben-Shlush A, Itzchak Y, Szeinberg A.
Virtual bronchoscopy in children: early clinical experience.
AJR
1998;171:1699
-1702[Abstract/Free Full Text]
-
Holcomb GW. Identification of the distal esophageal segment during
delayed repair of esophageal atresia and tracheoesophageal fistula.
Surg Gynecol Obstet
1992;174:323
-324[Medline]
-
Caffarena PE, Mattioli G, Bisio G, Martucciello G, Ivani G, Jasonni
V. Long-gap esophageal atresia: a combined endoscopic and radiologic
evaluation. Eur J Pediatr Surg
1994;4:67
-69[Medline]
-
Summers RM. Navigational aids for real-time virtual bronchoscopy.
AJR
1997;168:1165
-1170[Abstract/Free Full Text]
-
Jolezs FA, Lorensen WE, Shinmoto H, et al. Interactive virtual
endoscopy. AJR
1997;169:1229
-1235[Free Full Text]
-
Ferretti GR, Vining DJ, Knoplioch J, Coulomb M. Tracheobronchial
tree: three-dimensional spiral CT with bronchoscopic perspective. J
Comput Assist Tomogr
1996;20:777
-781[Medline]
-
Cudmore RE. Oesophageal atresia and tracheo-oesophageal fistula.
In: Lister J, Irving IM, eds. Neonatal surgery, 3rd
ed. London: Butterworths, 1990:231
-259
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Abstract
Introduction
