Transabdominal Sonography of the NormalGastroesophageal Junction in Children

Francesco Esposito, MD,1 Romilda Lombardi, MD,1 Angela Coppolaro Grasso, MD,1

Hana Dolezalova, MD,1 Antonio Sodano, MD,1 Luciano Tarantino, MD,2 Antonio Giorgio, MD2

1 Department of Pediatric Radiology, University “Federico II” of Napoli, Via S. Pansini, 5, 80100 Naples, Italy2 Ultrasound Service, Hospital for Infectious Diseases “D. Cotugno,” Naples, Italy

Received 6 July 2000; accepted 8 March 2001

ABSTRACT: Purpose. Because sonography identifiesabnormalities of the gastroesophageal junction, it isessential to understand the normal sonographicanatomy. The aim of this study was to determine thenormal sonographic appearance of the gastroesopha-geal junction and its variations and to provide mea-surements of the abdominal esophagus in asymptom-atic, healthy children.

Methods. In this prospective study, 124 healthychildren (75 boys and 49 girls), aged 2 days–12 years,underwent abdominal sonography. With the patient ina supine position, the transducer was placed underthe xiphoid and the ultrasound beam was directedcephalad through the window of the left lobe of theliver. The length of the abdominal esophagus wasmeasured from the point at which it penetrated thediaphragm to the gastroesophageal junction. Thethickness was measured on the anterior wall at themidpoint of the abdominal esophagus.

Results. The gastroesophageal junction was iden-tified by sonography in all of the children. The meanlength of the abdominal portion of the esophagusranged from 18 mm in the newborns to 34 mm inchildren older than 6 years. The wall thickness rangedfrom 2.4 mm to 5.7 mm.

Conclusions. Our results indicate that visualizationof the gastroesophageal junction and measurement ofthe abdominal esophagus are readily achievable withreal-time sonography in healthy children. © 2001John Wiley & Sons, Inc. J Clin Ultrasound 29:326–331,2001.

Keywords: gastroesophageal junction; esophagus; ul-trasonography; children

Transabdominal sonography is a noninvasive,simple, quick, and safe technique to visualize

the gastroesophageal junction1–5 and is useful forstudying gastroesophageal reflux, esophagitis,hiatal relaxation, esophageal varices, and esoph-ageal involvement by malignant tumors.3,4,6–8

An understanding of normal sonographicanatomy is fundamental to the study of gastro-esophageal abnormalities. Previously publishedstudies of the gastroesophageal junction in chil-dren have evaluated the length of the abdominalportion of the esophagus but not the wall thick-ness.3,4 Also, these studies were limited to chil-dren of ages 1 month–7 years.

The purpose of our study was to determine thenormal sonographic appearance of the gastro-esophageal junction and its physiologic variationsand to provide measurements of the abdominalesophagus in asymptomatic, healthy children.

SUBJECTS AND METHODS

In this prospective study, we performed sono-graphic examinations between February 1999and May 2000 on 124 asymptomatic, healthy chil-dren who were enrolled in a program to screen forurinary tract malformations using sonography.There were 75 boys and 49 girls, with an agerange from 2 days to 12 years. Children withsymptoms of gastroesophageal reflux, such asvomiting and regurgitation, and those with re-current respiratory infection, chronic cough,retrosternal or abdominal pain, or unexplainedperiods of crying or agitation and other signs ofdiscomfort2 were excluded from the study. Verbal

Correspondence to: F. Esposito, Via Acquaviva, 19, 80141Naples, Italy

© 2001 John Wiley & Sons, Inc.

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consent was obtained from the parents, and thestudy was approved by the institutional reviewboard.

Sonography was performed using a LOGIQ MD400 ultrasound scanner (GE Medical Systems,Milwaukee, WI) with 5- and 7-MHz curved-arrayreal-time transducers. The sonographic examina-tions were performed by the same investigator(F. E.), with the patient in a supine position afterfasting for 3 hours.

The transducer was placed in the midline un-der the xiphoid, and the ultrasound beam wasdirected cephalad to visualize the distal portion

of the thoracic esophagus and the abdominalesophagus through the window of the left lobe ofthe liver (Figure 1). By swiveling the probe 90°, across section of the abdominal esophagus could bedemonstrated with a “target” pattern posterior tothe left lobe of the liver (Figure 2), the echogeniccenter of the target representing the mucosa andthe collapsed lumen of the esophagus. Imageswere obtained at the end of a normal exhalation.

The length of the abdominal esophagus wasmeasured only on the longitudinal scans from thepoint at which the esophagus traversed the dia-phragm (diaphragmatic sphincter) to the gastro-

FIGURE 1. Longitudinal sonogram shows the normal abdominal esophagus (arrows) and gastroesophagealjunction after deglutition. A, abdominal aorta; L, left lobe of the liver; S, stomach.

FIGURE 2. Transverse sonogram of the normal abdominal esophagus shows a “target” pattern (arrow). A,abdominal aorta; L, left lobe of the liver.

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esophageal junction (identified on sonograms by asmall triangular pad of gastric folds radiatingfrom the cardia) (Figure 3). The esophageal wallthickness was measured on the anterior wall atthe midpoint of the abdominal esophagus (Figure4). The measurements were correlated with theages, which were categorized into 3 groups: 2days–12 months (38 subjects), 2–4 years (50 sub-jects), and more than 4 years (36 subjects). Formaximal precision, the esophageal measure-ments were obtained at the end of a swallow. In-fants were bottle fed water, and children weregiven water in a glass. The diaphragmatic sphinc-ter was identified by a change in echogenicity be-tween the esophageal content retained above thesphincter, material that contained air bubblesand was highly echogenic, and the abdominal

esophagus, which was less echogenic. The gastricend of the abdominal esophagus was identified bythe base of the small triangular pad (Figure 3).The relationship between the abdominal esopha-geal length and patient age was assessed usinglinear regression analysis. Measurements aregiven as mean ± standard deviation.

RESULTS

The gastroesophageal junction was identified bysonography in all of the children. The meanlength of the abdominal portion of the esophagusranged from 18 mm in the newborns to 34 mm inchildren older than 6 years (Figure 5). The wallthickness ranged from 2.4 mm to 5.7 mm. In pa-

FIGURE 3. Longitudinal sonogram (A) and diagram (B) show the normal abdominal esophagus after deglu-tition. The sonogram shows the 2 ends of the abdominal esophageal canal, the point at which the esophagustraversed the diaphragm and the gastroesophageal junction. Measurements are taken from the echogenicarea representing the saliva retained above the diaphragmatic sphincter (open arrow) to the base of thetriangular pad (small arrows). A, abdominal aorta; D, diaphragm; L, left lobe of the liver; S, stomach.

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tients 2 days–12 months old, the mean wall thick-ness was 3.6 ± 0.6 mm; 2–4 years old, 3.9 ± 0.8mm; and older than 4 years, 4.1 ± 0.8 mm. Therewas a significant correlation between abdominalesophageal length and patient age (r 4 0.8530).

DISCUSSION

The length of the abdominal esophagus is an im-portant parameter in the evaluation of patientswith reflux.9 It has been reported that no esoph-

agitis occurs in children without herniation of thegastroesophageal junction through the dia-phragm.3 Moreover, the thickness of the esopha-geal wall has been reported to be increased incases of acute inflammation due to peptic esoph-agitis and in cases of malignant invasion of thegastroesophageal junction.1,8

The assessment of the abdominal esophagusrequires meticulous measurements. Although itis easy to visualize the gastroesophageal junction,it is difficult to accurately measure the abdominal

FIGURE 5. Graph shows correlation between length of abdominal esophagus and child’s age (r = 0.8530).

FIGURE 4. Longitudinal sonogram shows the normal abdominal esophagus, with the 2 arrows indicating thepoint at which the thickness of the anterior wall was measured. A, abdominal aorta; D, diaphragm; L, left lobeof the liver; S, stomach.

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esophagus because its length is not constant. Thelength can change by 2–4 mm as a result of res-piration (Figure 6) and gastric filling. Thus, mea-surement conditions must be as consistent as pos-sible.

Manometry, pH-metry, and scintigraphy re-veal some functional aspects of gastroesophagealreflux but not the morphologic changes.2 Endos-copy is accurate in defining the presence of a her-nia but offers no information about the length ofthe esophagus and the thickness of its wall whenthe gastroesophageal junction is located below thediaphragm.10 Barium x-ray studies can evaluatemucosal alterations and provide a good morpho-logic representation of the gastroesophageal junc-tion and its relationship to the diaphragm, thedistal esophagus, and the stomach. However,barium x-ray studies have poor sensitivity indemonstrating mild shortening of the abdominalesophagus.

The principal advantage of sonography over abarium study is sonography’s higher resolutionthat allows the detection of as little as a 2-mmshortening of the abdominal esophagus. In new-borns and infants, hiatal hernias as small as 5mm are common and represent loss of a quarter ofthe normal length of the abdominal canal. Thegreater sensitivity of sonography in detectingsmall hiatal hernias is essentially due to a betteridentification of the 2 ends of the abdominalesophagus. In addition, in barium studies, thegastroesophageal junction is rapidly obscured by

barium in a prone or supine child and blends withthe posterior gastric wall in a child in an erectposition.11

Published comparisons of sonographic and en-doscopic studies have shown in 90% of cases agood correlation between shortening of the ab-dominal esophagus on sonography and ascensionof the “Z line” (the transition area between theesophagus and stomach identified at endoscopyby a change in color between the pale esophagealand the dark gastric mucosa) on endoscopy.3,5 Thesonographic errors in measurement in our studywere due to errors in locating the gastroesopha-geal junction and the presence of air in the stom-ach obscuring the distal part of the abdominalesophagus.3

The evaluation of the intra-abdominal esopha-gus is fundamental in reflux studies.12 Theesophagus acts like an antireflux barrier, coun-teracting changes in intragastric pressure. A suf-ficient sphincter length is necessary to compen-sate for an increase in intra-abdominal pressure.The optimal length of the abdominal esophaguswas estimated by De Meester et al13 to be 20–25mm. The sonographic length of the abdominalesophagus, including gastric folds, is about 25–30mm.3 Since the abdominal esophagus grows withthe child, the progressive lengthening probablyexplains the frequent improvement of reflux, com-monly present in newborns, when the abdominalesophagus has acquired a sufficient length, afterabout 16–18 months of age.14–16 The results of

FIGURE 6. Longitudinal sonograms show the physiologic variations in the length of the abdominal esophagusbetween the expiratory phase (left, A) and the inspiratory phase (right, B). The arrows show both ends of theabdominal esophagus. L, left lobe of the liver; S, stomach.

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this study are comparable to data previously pub-lished by Gomes et al3 regarding the length of thegastroesophageal junction.

In our patient population, which was exclu-sively pediatric, the normal mean wall thicknesswas slightly greater than the values reported byother authors.3,4 Our results were different fromdata reported by Di Mario et al,4 which showedthat a gastroesophageal wall thickness greaterthan 3 mm in children was abnormal. In an adultpopulation, Changchien et al8 reported normalwall thickness values ranging from 2 mm to 5 mm(mean, 3.8 ± 1.2 mm). The difference in the meanwall thickness between studies may be due to aslight difference in the positioning of the calipersfor measurement, a point which was clearly de-fined in our study.

Our results indicate that visualization of thegastroesophageal junction and measurement ofthe abdominal esophagus are readily achievablewith real-time sonography in healthy children.

ACKNOWLEDGMENTS

We thank Stella Annunziato and Dr. MassimoImbriaco for their assistance in preparing thismanuscript.

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