Ultrasonographic Signs of Sliding Gastric Hiatal Hernia and Their Prospective Evaluation

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1 Ultrasonographic Signs of Sliding Gastric Hiatal Hernia and Their Prospective Evaluation Antonio Aliotta, MD, Gian Ludovico Rapaccini, MD, Maurizio Pompili, MD, Anna Grattagliano, MD, Augusto Cedrone, MD, Concetta Trombino, MD, Francescantonio DeLuca, MD, Italo De Vitis, MD This study was conducted to identify the sonographic findings that might be used to diagnose sliding gastric hiatal hernia. We first performed a retrospective evaluation of 12 patients known to have sliding hiatal hernia and 18 normal controls. In the controls the esopha gogastric junction could be visualized clearly in all cases and the alimentary tract section at the diaphragrnat~ ic hiatus ranged from 7.1 to 10.0 mm. The esophagogastric junction was not visualized in any of the hernia patients, whose alimentary tract diameters ranged from 16.0 to 21.0 mm. These two markers (nonvisualization of the junction and diameter greater than 16 mm) were then evaluated for their ability to predict the occurence of sliding hiatus hernia in a prospective study of 38 patients subsequently diagnosed by means of barium contrast examinations and endoscopy. In this group, each sign had a positive predictive value of 100%. The negative predictive value of the alimentary tract diameter was 90%; that of nonvisualization of the esophagogastric junction was 94.7%. Inclusion of ultrasonography in the initial work-up of patients with symptoms of gastroesophageal reflux may reduce the need for more invasive diagnostic procedures. KEY WORDS: Ultrasonography; Stomach; Hiatal hernia. A bdominal ultrasonography has proved to be useful in the diagnosis of a number of types of pathologic gastrointestinal conditions, 1 and the number of disorders that can be diag- ABBREVIATIONS SGHH, Sliding gastric hiatal hernia; ATS, Alimentary tract section; EGJ, Esophagogastric junction Received July 23, 1993, from the lstituto de Clinica Medica, Universita Cattolica del Sacra Cuore, Rome, Italy. Revised manuscript accepted for publication May 2,1994. Address correspondence and reprint requests to Gian Ludovico Rapaccini, MD, lstituto di Clinica Medica, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, Roma, Italy. nosed with relative certainty by sonography has been growing steadily since the early 1980s. 2-7 Westra and coworkers 8 have recently defined the principal sonographic findings associated with gastroesophageal reflux caused by hiatal herniation of the distal esophagus in infants and young children. These include (1) intra-abdominal esophagus measuring less than 2 em, (2) "rounding" of the gastroesophageal angle and (3) the presence of a ''beak" at the EGJ. Although the predictive value of these criteria was found to be quite good, they cannot be applied in cases involving hiatal herniation of the gastric fundus, as the distal esophagus and the EGJ are no longer within the abdominal cavity. There are no data in the literature on the sonographic findings in adult patients with SGHH by the American Institute of Ultrasound in Medicine J Ultrasound Med 14: , /95/ $3.50

2 458 SLIDING HIATAL HERNIA J Ultrasound Med 14: , 1995 In an attempt to identify the sonographic findings that might allow diagnosis of this type of hiatal hernia in adults, we first performed a retrospective study of subjects in whom SGHH had already been confirmed or excluded on the basis of radiologic (barium contrast examinations) and endoscopic studies. Two easily evaluated parameters were identified in this study, and these were tested subsequently for reliability in predicting or excluding a diagnosis of SGHH in a second group of patients scheduled for upper gastrointestinal evaluation because of various types of symptoms. RETROSPECTIVE STUDY Patients and Methods Abdominal sonography was performed on 30 patients (20 women, 10 men ranging in age from 20 to 85 years) who had previously undergone radiologic and endoscopic studies for gastrointestinal complaints. On the basis of these studies, 12 of the subjects were known to be suffering from SGHH and the remaining 18 were considered to be free of pathologic gastrointestinal conditions (normal controls). The subjects were examined in the supine or left lateral position after a fast of 8 hours or more. Epigastric sagittal or slightly oblique (right or left) scans were obtained using real-time sonographic scanners (Siemens SL-2 equipped with both 3.5 MHz and 5.0 MHz sector transducers and ESAOTE AU 560 with a 3.5 MHz convex transducer). We previously found that the shape of the transducer is not a significant factor in studies of the gastrointestinal tract. 9 All studies were performed by the same examiner, who was aware of the subject's previous diagnosis (SGHH or normal control). On sagittal scans passing through the diaphragmatic hiatus, the normal alimentary tract generally appears as a tubular structure composed of two hypoechoic bands representing the anterior and posterior wajls of the esophagus with a thin central hyperechoic strip resulting from the mucosal layers as well as from their apposition. The central hyperechoic strip can sometimes be not so sharply delineated owing to the presence of gas. This tubular structure extends below the diaphragm for a distance of several centimeters and expands, at the EGJ, into the roundish or oval image of the stomach, which often contains liquid, gas, or both. Scans were evaluated for the visibility of the EGJ and the ATS at the level of diaphragmatic hiatus was measured from the outer Hmits of the exterior wall to the outer limits of the posterior wall. Figure 1 represents the esophagus and the stomach of a normal subject in a sagittal scan passing through the diaphragmatic hiatus: the distance between the markers denotes ATS thickness; the position of the markers, not straight anteroposterior, reflects the fact that the probe was slightly inclined in a caudocranial position. The important point is that both markers be placed at the outer limits of the alimentary tract walls when they pass through the diaphragm, on a plane perpendicular to the major axis of the esophagus. The additional tissue behind the posterior marker is connective tissue, which often is visualized in this kind of scan and which can easily be distinguished from the esophageal wall during dynamic studies; moreover, the EGJ is clearly visible. Our assumptions were that, in patients with SGHH, the EGJ would not be visible (because it had passed into the thorax) and that the ATS at the hiatus (representing a section of the stomach instead of the esophagus) would be greater than normal. Statistical analysis was performed using Student's t-test. RESULTS Adequate visualization of the alimentary tract was achieved in all 18 of the normal subjects and in nine of the 12 known to have SGHH (90% of all those examined). Although impaired visualization was noted in five of these 27 subjects (four normal controls, one with SGHH), owing to the presence of excessive gas, this was overcome by examining the subject in the left lateral position. The same problem was encountered in the remaining three SGHH subjects, but in these cases the position change was insufficient to allow adequate visualization. In the normal subjects the EGJ was visualized dearly in all cases and the ATS ranged from 7.1 to 10.0 mm (mean± SO, 8.5 ± 0.7 mm) (Fig. 1).1n contrast, the EGJ could not be identified in any of the patients with SGHH and the ATS measurements at the hiatus ranged from 16.0 to 21.0 mm (mean ± SO, 17.5 ± 1.7 mm) (Fig. 2A, B). In Figure 2, in the patients with SGHH, ATS at the hiatus is represented by the distance between the two markers (positioned at the outer limits of the hypoechoic anterior and posterior walls) and is greater than 16 mm. The junction between esophagus and stomach is not recognizable. The difference between the mean ATS measurements for the two groups was highly significant (P < ). In 14 cases (nine controls and five with SGHH), ATS measurements were made using both the 3.5 MHz and 5.0 MHz sector probes. In all14, the

3 J Ultrasound Med 14: , 1995 ALIOTI A ET AL 459 Heart 1. Esophagus 2. EGJ (See text) 3. Diaphragm... Diagram 1 Stomach., Figure 1 Sagittal scan passing through the diaphragmatic hiatus in a patient with no pathologic gastrointestinal conditions. The EGJ is visualized dearly and the A TS (distance between the outer limits of the hypoechoic anterior and posterior walls) at the hiatus measures 9.0 mm (see Diagram 1). two measurements were identical, suggesting that the frequency of the probe is not a significant factor in sonographic studies of this type. PROSPECTIVE STUDY Patients and Methods Abdominal sonographic studies were then performed in the manner described previously in 38 patients scheduled for upper gastrointestinal workups. These studies were performed by the same examiner, but in these cases he was not aware of the subject's symptoms. When complete sonographic evaluations of the abdomen (e.g., for tumor staging) were required, these were performed by another examiner who was aware of the patient's clinical picture. Using the two criteria described earlier (i.e., visibility of the EGJ and measurement of the ATS at the hiatus) we attempted to identify patients within this group who were suffering from SGHH. Increased ATS was defined as a measurement of 16 mm or more. Although the maximum ATS measurement found in the previously studied group of normal patients was 10.0 mm, we preferred to use the more restrictive criterion represented by the minimum ATS found in the SGHH group. Diagnoses based on these two criteria were compared with the results of radio- logic studies and fiberoptic endoscopy of the upper gastrointestinal tract performed after our sonographic examination. RESULTS Five of the 38 patients could not be evaluated because of excessive gas. Twenty of the 33 with adequate visualization were found to have an ATS measuring less than 16 mm. Subsequent studies excluded SGHH in 18 of these; in the remaining two (whose ATS measurements were 9 mm and 12 mm, respectively), SGHH was later diagnosed. In 13 other patients, the ATS measured 16 mm or more and all of these were found to have SGHH on the basis of barium contrast examination and endoscopy. In 19 of the 33 patients, the EGJ was visualized by the examiner; SGHH was subsequently excluded in 18. In the remaining 14, the EGJ could not be identified despite otherwise adequate visualization, and subsequent studies confirmed the presence of SGHH in all14. DISCUSSION Westra and coworkers 8 have recently described the sonographic findings that are associated with hiatal hernias of the distal esophagus in children, but few data are available on the sonographic presentation of SGHH, which also is a common cause of ftastroesophageal reflux. Miyamoto and colleagues have noted that visualization of the EGJ is quite difficult in patients with SGHH although this structure can be identified easily in patients with herniation of the distal esophagus alone. Because the caliber of the ali-

4 460 SLIDING HIATAL HERNIA J Ultrasound Med 14: , 1995 Diagram2A A Figure 2 Sagittal scans passing through the diaphragmatic hiatus in two patients known to have SGHH. The EGJ cannot be visualized and the ATS at the hiatus measures 17.5 mm (A), and 18.8 mm (B). The hyperechoic zone between the walls represents gas (see accompanying diagrams). mentary tract is greater at the level of the gastric fundus (primarily because of gaseous distention) than it is in the esophagus, we reasoned that measurement of the ATS at the diaphragmatic hiatus might also be a valid indicator of the presence or absence of gastric herniation. B This AlS was measured from the outermost limits of the hypoechoic bands representing the anterior and the posterior walls of the alimentary tract. Although increases in the diameter might also be found in patients with carcinoma of the distal esophagus, causing an increased thickness of one or both walls, it should be possible to distinguish such a condition from an increase in ATS caused by SGHH by measuring the distance from the outer limit of the wall to the hyperechoic inner mucosal layer, as the waus of the esophagus normally are not any thicker than those of the gastric fundus. The positive and negative predictive values.of these two criteria appear to be excellent. All16 of the patients found to have an ATS measuring more than 16 mm were subsequently found to have SGHH on the basis of radiologic and endoscopic studies. Similarly, SGHH was later confirmed in all14 of the cases in which the EGJ could not be visualized. The negative predictive values of the two criteria were only slightly lower: two of the SGHH patients had an ATS less than 16 mm (negative predictive value, Diagram2B HEART 1

5 J Ultrasound Med 14: , 1994 ALIOTIA ET AL %) and in one the EGJ was erroneously visualized (negative predictive value, 94.7%). The ATS also was less than 16 mm in this latter patient, which means that the negative predictive value of the absence of both findings is also 94.7%. It is worth mentioning that one of the patients in whom SGHH was excluded on the basis of the ATS measurements (12 mm) would have been diagnosed correctly if we had chosen to use the less restrictive normal cut-off of 10 mm (the maximum normal ATS measurement found in the retrospective study). The results of this study and those reported by Westra and coworkers 8 indicate that sonography can offer valuable information in the diagnosis of hiatal hernias. Although further study of larger series will be necessary to confirm our findings, nonvisualization of the EGJ or a hiatal ATS of 16 mm or more on sonograms appears to be strongly suggestive of SGHH. Therefore, patients with symptoms reminiscent of gastroesophageal reflux (epigastric or chest pain, heartburn, regurgitation, cardiac arrythmias) should first undergo a sonographic examination. If these findings are present, appropriate treatment might reasonably be undertaken and, if the response is positive, other, more invasive diagnostic procedures might be avoided. REFERENCES 2. Haller JO, Cohen HL: Hypertrophic pyloric stenosis: Diagnosis using US. Radiology 161:355, Limberg 8: Diagnosis of acute ulcerative colitis and colonic Crohn's disease by colonic sonography. J Clin Ultrasound 17:25, Verbanck J, Lambrecht 5, Rutgeerts L, et al: Can sonography diagnose acute colonic diverticulitis in patients with acute intestinal inflammation? A prospective study. J Clin Ultrasound 17:661, Johairiy IA, Mustafa MA, Zaidi AJ: Fluid-aided sonography of the stomach and duodenum in the diagnosis of peptic ulcer disease in adult patients. J Ultrasound Med 9:77, Gassner I, Strasser K, Bart G, et al: Sonographic appearance of Menetrier's disease in a child. J Ultrasound Med 9:537, Skaane P, Sandbaek G: Ultrasound and CT evaluation of pedunculated gastrointestinal lipomas. Radiology 30:12, Westra SJ, Wolf BHM, Staalman CR: Ultrasound diagnosis of gastroesophageal reflux and hiatal hernia in infants and young children. J Clin Ultrasound 18: 477, Rapaccini GL, Aliotta A, Pompili M, et al: Gastric wall thickness in normal and neoplastic subjects: A prospective study performed by abdominal ultrasound. Gastrointest Radiol13:197, Miyamoto Y, Ishimara K, Nakada N, et al. Ultrasonographic diagnosis of esophagogastric junction in adult. Proceedings of VI WFUMB Congress, Copenhagen, September Bluth El: Ultrasound evaluation of small bowel abnormalities. Am J Gastroenterol78:788, 1983