Radionuclide esophageal transit time for the assessment of pneumatic dilation in patients with achalasia

Mahmoud El-Desouki; Saleh Othman; Rashed Al-Rashed; Mohd Mohamadiyeh; Saleh Al-Amri; Ibrahim Al-Mofleh

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Year : 1999 | Volume : 5 | Issue : 2 | Page : 71-75

Radionuclide esophageal transit time for the assessment of pneumatic dilation in patients with achalasia

Mahmoud El-Desouki¹, Saleh Othman¹, Rashed Al-Rashed², Mohd Mohamadiyeh¹, Saleh Al-Amri², Ibrahim Al-Mofleh²
¹ Nuclear Medicine Division, College of Medicine & KKUH, King Saud University, Riyadh, Saudi Arabia
² Gastroenterology Division, College of Medicine & KKUH, King Saud University, Riyadh, Saudi Arabia

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Date of Submission	26-Feb-1998
Date of Acceptance	03-Oct-1998

Abstract

Objective: The aim of this study was to assess the value of radionuclide esophageal transit time (RET) in prediction of the results of pneumatic dilation in patients with achalasia. Patients and methods: Thirty patients (13 males) with a mean age of 37 ± 15.6 years (range 17-73 years) were included in the study. All patients were diagnosed to have idiopathic achalasia of the cardia and selected for pneumatic dilation. Each patient had three RET, two the same day of dilation (preand postdilation) and a third follow up one within three months of dilation (4 patients failed to come for follow up and were excluded). Results: Several parameters were derived from RET studies, T/50: time required for 50% of activity in the esophagus to be cleared, T/10 : time required for 90% of activity in the esophagus to be cleared and percentage clearance at 10 min. These parameters were compared to response of dysphagia to dilation. It was evident that the higher the esophageal clearance postdilation, the better the outcome. When immediate post dilation clearance was 85% or more the success rate was 83.3% whereas when it was 20-50% the success rate was only 21.4%. No relation was found between T/50, T/10 and dysphagia response. Conclusion: RET appears to be a useful quantitative procedure in the assessment of pneumatic dilation outcome in achalasia patients.

How to cite this article:
El-Desouki M, Othman S, Al-Rashed R, Mohamadiyeh M, Al-Amri S, Al-Mofleh I. Radionuclide esophageal transit time for the assessment of pneumatic dilation in patients with achalasia. Saudi J Gastroenterol 1999;5:71-5

How to cite this URL:
El-Desouki M, Othman S, Al-Rashed R, Mohamadiyeh M, Al-Amri S, Al-Mofleh I. Radionuclide esophageal transit time for the assessment of pneumatic dilation in patients with achalasia. Saudi J Gastroenterol [serial online] 1999 [cited 2021 Oct 19];5:71-5. Available from: https://www.saudijgastro.com/text.asp?1999/5/2/71/33513

Pneumatic dilation of the cardia is one of three options for initial treatment of achalasia^[1] . The assessment of treatment in achalasia is commonly based on symptoms (subjective criteria), manometry and radiographic methods ^[2],[3] . None of these methods, however, quantifies the functional disturbance of impaired esophageal emptying or measures esophageal food residue. Patients with large food residue are considered to be at risk of pulmonary aspiration. In addition, retention esophagitis has been implicated in the etiology of squamous carcinoma of the esophagus complicating achalasia^[4] . Consequently, effective therapy should relieve symptoms and reduce or abolish any esophageal residue. Radionuclide esophageal transit (RET) is a method which evaluates the transport of radiolabelled fluids or semisolid materials through the esophagus. Since its introduction in 1972 by Kazem^[5] , this "physiologic" test has gained popularity and has been used for assessment of different esophageal disorders. In 1979, Tolin et al^[6] described the first quantitative esophageal scintigraphic measurements. In normal groups, they found that 90% of the first swallowed bolus completely transversed the esophagus within nine seconds (T/10). In the subsequent six seconds and during the following 10 minutes of the multiple dry swallow period, they found that no further clearance occurred and retention of about 10% of initial bolus seems to occur frequently. Since then, quantitative esophageal scintigraphy has become the standard method for assessing esophageal transit and several quantitative parameters have been described^{[2],[7],[8],[9],[10],[11]} .

In this prospective study we evaluated a radionuclide esophageal emptying test using a single-phase radiolabelled liquid drink before, and immediately (same day) after pneumatic dilation of the cardia in patients with idiopathic achalasia, including a followup study performed within the 3 months following dilation. The aims of the study were to determine changes in qualitative and quantitative parameters derived from the 3 studies, and whether or not these changes correlate with the clinical response of dysphagea to dilation.

Patients and Methods

Study Population

Radionuclide esophageal transit studies were performed on ' 30 patients (13 were males) with clinically, radiologically and manometrically established diagnosis of achalasia. Pneumatic dilation was performed after securing written consent. The patients mean age was 37 ± 15.6 years (range 17-73 yrs). The median duration of dysphagia was 18 months (range 4-35 months). Each patient had two RETs performed on the same day of dilation, the first before and the second immediately after the procedure. Posttreatment follow up RETs were performed in only 26 patients within 3 months after treatment. The four patients who could not attend for follow up RETs were living in remote areas and were excluded from the study making the study population 26 patients only.

The patients were interviewed immediately after dilation and before the follow up RET study and a questionnaire about symptoms was completed. Symptoms evaluated were dysphagia, chest pain, regurgitation and heartburn. Dysphagia was the only common symptom among all patients, while heartburn in 7 patients, regurgitation in 5 patients and chest pain in 4 patients. Response of dysphagia to dilation was considered for correlation with RET results. Dysphagia was graded as follows: Grade 0 No dysphagia. Grade 1 : Dysphagia to solid food only. Grade 2 : Dysphagia to liquids only. Grade 3 Dysphagia to both solids and fluids. Grade 0 was considered as successful and other grades, as nonsuccessful. The sum of the individual grades was considered as the maximum possible score and this was designated as the dysphagia response score. Consequently the lower the score the better the outcome.

Radionuclide Esophageal Transit studies (RETs): The method we used is modified from that described by Tolin et al ^[6]. Patients were fasted overnight or at least for 3 hours and were seated in a semierect position in front of a gamma camera. The field of view of the camera covered the whole of the esophagus (the area from the mouth till the proximal part of the stomach). Each patient was trained to practice several swallows of plain water before ingestion of the radioactive bolus in one phase. For the RETs, the patients were asked to aspirate, through a straw, 15 milliliters of water or orange juice containing 18-37 MBq (0.5 - 1 mCi) Technetium 99m colloid, DTPA or micropheres, then they were asked to keep the bolus in the mouth and then swallow as a single bolus. Images of 0.5 second duration were recorded over one minute (total 120 frames) during esophageal transit of the tracer. Subsequently, patients performed dry swallows at 15 second intervals for 10 minutes and esophageal counting rates were obtained for each 15 second period. At the end of the dynamic study, patients drank a further 50 ml water and a static image of 30 seconds duration was immediately recorded to assess clearance of residual tracer from the esophagus.

Data Analysis : Data from the twenty six patients were evaluated both qualitatively and quantitatively. The stored images were displayed for qualitative assessment of quality of the study (exclude patient motion), distribution of radioactivity in the esophagus, any episode of gastroesophageal reflux or any esophageal leak as a complication of therapy. Then all the images were condensed into one and the esophagus was delineated by Region of Interest (ROI) and a time activity curve was generated for the whole esophagus. From this curve three indices of transit were obtained. I - T/50, the time required for 50% of the activity in the esophagus to be cleared. II - T/10, the time required for 90% of the activity in the esophagus to be cleared. III - clearance at 10 minutes calculated using the following formula.

(A: Maximum esophagel counts B: Esophagel count at 10 min.).

Results

Qualitative Assessment : The three studies of each patient were reviewed with special emphasis on the postdilation for possible immediate complications (i.e. a leak). Eight of the studies were repeated as they were considered unsatisfactory because of contamination or fractionation of the bolus. In two patients, postdilation leakage was observed, however pulmonary aspiration and gastroesophageal reflux were not documented in any of our patients.

Quantitative Assessment : The percentage clearance at 10 min : The percentage cleared at 10 min of the study was determined for the three studies of each patient and results were tabulated in two groups [Table - 1]. We observed that in all patients, percentage clearance in predilation study was less than 30%. In the postdilation study, two groups could be identified. Group-I, 12/26 patients (46%), had percentage clearance more than 85% [Figure - 1] and none of them showed any significant change in percentage clearance on follow up studies. In groupII, 14/26 patients (54%) had percentage clearance 20-50% post dilation [Figure - 2], five of them showed no change in percentage clearance on follow up studies, while the other nine showed recurrent increase in percentage remaining exceeding 50%. The results of radionuclide esophageal emptying were compared with response of dysphagia to treatment in all patients [Table - 2]. From this table a simple observation was evident, that a relation exists between percentage change in esophageal clearance and dysphagia response, however, it was not possible to determine a cut-off value in percentage clearance and dysphagia response to treatment.

The transit times : T/10 and T/50 were analysed in the 3 sets of studies in all patients. It was observed that T/10 was not found in any of the studies of all patients. On the other hand, T/50 was not found in any of the predilation studies, while in the follow up studies T/50 was variable and ranged from 5 seconds to not be found. From these results, no specific changes in T/10 or T/50 were observed to determine dilation outcome. The effect of age, sex and duration of the disease was not considered at the time of analysis of the results.

Discussion

In achalasia, changes in emptying after treatment reflects the patients clinical status. Prediction of therapy outcome in achalasia is of great clinical interest for the treating physician as well as for the patient. Subjective improvement in symptoms is an important clinical indicator for assessing the response to therapy in achalasia^[12] . However, it is preferable if there is a quantitative parameter that correlates with subjective response and consequently can be used to predict the outcome of therapy and to be used in follow up.

In our study, we investigated the possible correlation between dysphagia response and esophageal clearance postpneumatic dilation therapy as a guide or predictor of therapy outcome. First, the qualitative assessments of the studies permitted assessment of quality of the studies and detection of any immediate complication such as esophageal leakage. Quantitative analysis showed that 10 out of 12 patients with clearance more than 85% had good dysphagia response with a success rate of 83.3% [Table - 2]. The response of dysphagia (success rate) in the rest of the patients (group II) as evident from the same table was only 21.4%. From these results, one can conclude that dysphagia response was different between the two group of patients, being clear that, the more the esophageal clearance, the higher is the chance of dysphagia improvement and the lesser the clearance, the least was the improvement.

These findings are not different from other reported studies. Johnson et al^[12] performed RET in 16 patients with achalasia undergoing pneumatic dilation and they followed them for 3-16 months. They found good correlation between symptoms score and esophageal transit both postdilation and on follow up studies. Mclean et a1^[13] , found that the postdilation values of esophageal transit were identical both one month and six months postdilation. The inconsistency between T/10 and T/50 and dysphagia response was also evident and only improvement in T/50 may suggest symptomatic improvement.

Conclusion

Radionuclide esophageal transit test appears to be a useful procedure in the assessment of patients undergoing pneumatic dilation therapy in terms of observing changes in percentage clearance. However, no certain threshold in clearance time could be derived to predict dilation outcome. The test is simple, quick, physiological and noninvasive. It can be performed at any nuclear medicine facility and we recommend that the test be more utilised by gastroenterologists.

References

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