AJR:169, August 1997 473Timed Barium Swallow: A SimpleTechnique for Evaluating EsophagealEmptying in Patients with AchalasiaJose Marcelo A. de OliveiraSigurbjorn Birgisson2Cindy Doinoff1David Einstein1Brian Herts1W illiam Davros1Nancy Obuchowski1Robert E. Koehler3Joel Richter2Mark E. BakeriOBJECTIVE. Our purpose was to define a simple technique for timing a barium swallowby which radiologists can assess esophageal emptying in patients with achalasia before andafter minimally invasive therapy. Our purpose was also to determine the best method of quan-tifying the degree ofemptying using this timed technique.MATERIALS AND METHODS. In the barium swallow technique. upright frontal spotfilms of the esophagus are obtained at I. 2. and S mm after ingestion of 100-2(X) ml of low-density(45% weight in volume) barium sulfate (volume of barium determined by patient tolerance. Forty-two of these barium swallows done by 23 patients with achalasia were retrospectively reviewed.The examination served either as a baseline study or as a 1-month follow-up study after patientshad undergone pneumatic dilatation or Clostridiu,n hotiilinii,n toxin injection. The spot filmswere digitized, and a region of interest was drawn around the column of barium by two ob-servers. The change in area seen in the region of interest on the I - and 5-mm films served asthe gold standard for percentage ofemptying. The spot films were then analyzed by tour otherobservers. each of whom independently. subjectively. and qualitatively estimated the percent-age ofemptying between the I- and 5-mm spot films. Percentages were divided into quintiles.On a separate occasion. each of these four observers also independently measured the heightand width of the barium column on the I - and 5-mm spot films. The product of height timeswidth seen on the I - and 5-mm films became the quantitative estimate fbr percentage of emptying.RESULTS. W e found no statistically significant difference between the percentage ofemptying as nieasured on the digitized images by the two observers and the height-times-widthcalculations or qualitative emptying percentage as estimated by the fbur observers. Interobserveragreement for the area evaluated on the digitized films as well as the height-times-width mea-surements and qualitative estimates ofemptying was almost perfect (the correlation coefficientsbeing 0.99, 0.87. and 0.93. respectively).CONCLUSION. The timed barium swallow is a simple and reproducible technique.Both qualitative assessment and estimated change in area based on height-times-width mea-surements of the barium column are accurate methods of estimating esophageal emptying.Received November 25, 1996; accepted after revisionFebruary 26, 1997.I Division of Radiology, The Cleveland Clinic Foundation,9500 Euclid Ave., Cleveland, OH44195. Address correspon-dence to M. E. Baker.2Department of Gastroenterology, Division of Medicine,The Cleveland Clinic Foundation, Cleveland, OH 44195.3Department of Radiology, University of Alabama Hospital,619 S. 19th St., Birmingham, AL 35233-6830.AJR 1997;169:473-4790361-803X/97/1692-473 American Roentgen Ray SocietyA chalasia is a motility disorder of theesophagus consisting of abnormalrelaxation of the lower esophagealsphincter and aperistalsis of the esophagealbody [I -3]. The goal of treatment is to relievesymptoms by improving esophageal emptying.Currently. pneumatic dilatation and Clostnidiiiinbotiili iiiiii toxin injection are the two minimallyinvasive treatments used, with Hellers nlyot-omy and esophagectomy reserved for patientswho are refractory to these treatments. As manyas 4(W /e of the patients undergoing pneumaticdilatation require more than one procedure be-cause of incomplete relief of symptoms. and upto 22% of patients require surgery after failedpneumatic dilatation or acomplication from thisprocedure (i.e.. esophageal perforation) I I. 4].In addition to symptomatic changes after ther-apy. objective examination of patients treatedwith pneumatic dilatation may be im portant be-cause clinical improvement can correlate poorlywith the degree of physiologic improvement[5-7J. Ifphysicians had a n ore objective meansof assessing esophageal emptying after pneu-matic dilatation. then mi ore appropriate furtherintervention might occur, thereby improving thelong-temi efficacy Of this procedure.The purpose of this study was twofold: to de-fine a simple, noninvasive, and widely availablebarium technique that could serve as an objec-tive measure of esophageal baseline and post-therapy emptying in achalasia patients and tode Oliveira et al.474 AJR:169, August 1997determine whether a simple qualitative or quan-titative measure can accurately assess esoph-ageal emptying on the basis of a gold standard.Materials and MethodsPatientsA timed hariuni swallow was performed on 23paticnts rcterred tn)I1i our gastroenterology depart-nient sallowing center from November 1 994 toNovember 1995. All 23 patients had achalasia onthe basis of symptoms (dysphagia. regurgitation.chest pain. and weight loss). esophageal manometry.and standard barium swallow. The timed bariumswallow was performed either as a baseline study oras a I -month follow-up study after pneumatic dilata-tion ( 2 1patients )or cndoscopic intrasphincteral injec-tions of C botulii:um toxin (Botox: Allergan. irvine.CM Itwo patients. The patients included 13 womenand It) men and were an average of 46 years oldlrangc. 15-77 years old).A total of 42 timed barium swallows were per-fonned: seven patients had one baseline study andone follow-up study (14 sets of tilms. threc patientshad one baseline study and two follow-up studies(nine sets of films). and two patients had one baselinestudy and three follow-up studies (eight sets of films.In 1 1 patients. only the baseline study I I I sets offilms) was available. Two of these patients were fol-lowed up by the referring physician from other insti-tutions after the therapy. two had a Hellers myotonlya.s initial treatment, one had perfbration of thc esopha-gus as a complication of the pneumatic dilatation andunderwent surgery. and six still had not received treat-ment when the sets of films were collected lbr anal)-sis. Finally. from the 42 set.s of films. one set wasexcluded because the column of barium in the I -mmfilm was discontinuous because of spasm. Therefore.the study sample included 41 sets of films. For theanalysis the films were retrospectively reviewed.TechniqueThe technique for the timed barium swallow.which is sumniarized in the appendix. was as tol-lows (Fig. I). W hile standing. the patient was askedto ingest a low-density barium sulfate suspension(45% weight in volume) (E-Z-PAQUE: E-Z-EM .W estbury. NY) over 3()-45 see. All patients were toldtO) drink the amount of barium they could toleratewithout regurgitation or aspiration (between 100and 2(8) ml). Then. with the patient in a slightlyleft posterior oblique position. three-on-one spotfilms (35 x 35 cm) ofthe esophagus were taken atI. 2. and 5 nun after the start of the barium inges-non (Figs. 1-3). If possible. spot films were takenwhen the esophagus was in a relaxed, rather thanspastic. state: otherwise. the film was exposedwhen the bariuni column was continuous and couldbe captured on the entire film lengthwise. Care wastaken to keep constant the distance of the fluoro-scope carriage Ironi the patient on the three spotflInts. If bariuni completely cleared the esophagusby the 2-mimi filni, the 5-mm film was not taken.The PUP 5e of the 2-mm film was to assess interimeniptying. At all times the patient was kept in the up-right. standing position.Data Interpretation and AnalysisThe 41 sets of 1- and 5-mm films were digi-tized using a I 2-bit. charged-coupled. high-reso-lution Ektron 1412 (Kodak. Rochester, NY)Fig. 1.-46-year-old man with achalasia.A-C, Timed barium swallow shows technique of exposing three-on-one spot film at 1mm (A), 2 mm (B), and 5mm(C) after patient has ingested 220ml of low-density barium.Qualitatively, approximately 40% of barium has emptied by 5-mm film. Study also shows problem of barium-foam level (arrow, B)caused by retained secretions in esoph-agus. For quantitative assessment, we measure superior extent of barium column where barium-foam interface is best defined (superiorhorizontalline, A and C). Regard-less of level chosen, upper extent of barium height must be consistently measured on both 1 - and 5-mm films to assess emptying. Inferior extent of barium column is generallymeasured at level of lower esophageal sphincter (inferior horizontal/me, Aand C). W e choose widest point of column to measure its width (oblique lines, A and C).comparison. The 2-mm film was not used. because width) as compared with that as mi easured byFig. 2.-40-year-old man with achalasia.A-C, Exposure at 1mm (A), 2mm (B), and 5mm (C) shows no emptying of barium by 5mm. Note how barium column height changes on 2-mm film because of contraction.This change does not alter our ability to assess emptying. Change in pixel count between 1- and 5-mm films was -3% and -6%, respectively, for both observers. Changein gross area calculation was 0%, -7%, -7%, and -1 2% for four observers. Qualitative assessment of emptying was 0% for all four observers. Negative numbers for changein pixel count and gross area calculation resultfrom apparent increase in height due to contraction in lower esophageal region. Further, superior extent of barium columnis better defined on 5-mm film.Timed Barium Swallow to Evaluate Esophageal Emptying in AchalasiaAJR:169, August 1997 475digital imaging camera system and a Plannar 1417(Gordon Instruments. Orchard Park. NY) lightsource. The dynamic range of the images was1024 gray levels and sv ts optiniized for each set offilms. The images were scanned at 150 x 512 pix-els. amid the field of view was approximately 10 x35 ciii. The images were displayed on a high-reso-lution ( 1024 x 1280 pixels. 24 bits) graphics mon-itor )Silicon Graphics. M ountain View, CA).Two observers (one a radiologist and the other agastroenterologist) traced a region of interest aroundthe esophageal barium column on the digitized im-ages. All the images were analyzed in a randomizedsequence. M easurements were taken from each im-age on two separate occasions by the two readers toassess the intrareader agreement. Neither of theseobservers participated in the qualitative or quantita-tive analysis. and neither communicated with eachother before the reading sessions.The films were therm analyzed in random order bythree radiologists amid one gastrt nteroIogist (separaterandom order fur each reader). The 1- and 5-mmfilms from each set were available to the observers forthis was only an interim assessment film. Each set wasfirst evaluated qualitatively for esophageal emptying.classifying the esophageal emptying between the I-and 5-mm films as 0-20% . 2l 4OC/c 41-60% . 61-8tY? . or 81-l()0% empty. In the second analysis. atleast 1 week apart from the first one. the same four oh-servers measured the height and width of the bariumcOluflifi in the esophagus in the I - and 5-mm films.The pixel count. because it assesses the area of theesophageal column of barium independent of esoph-ageal shape. was considered the gold standard of areameasurement. Rather than using height and width asseparate parameters. we considered the prxluctheight times width to be an estimate of the area of theesophageal banuiii column. Therefore. for the 1- and5-mm films we compared the percentage of change inthe area of the esophageal barium column as deter-mined by the pixel count with that as determined bythe measurement of height times width and by thequalitative estimate. W e computed the median differ-ences and constructed distribution-free approximately95% confidence intervals for the median using a resa-mpling technique 181 in which the sampling unit wasa patient. not a film.Intraclass correlation coefficients 19. 10J werecomputed for each method of nieasuretiient pixelcount. height-times-width :iieasurements. andqualitative estimate of emptying ). The intraclasscorrelation coefficient describes the variability inmeasurements made oti theanie patient in rela-non to the variability between patients. Thus. in-traobserver agreenient W aS assessed for the saniereader on tV.O different occasions for the pixelcount. Likewise. interobserver agreement wasassessed for the two observers for the pixel countand the four observers for the height-times-widthmeasurements and the qualitative estim ate ofesophageal emptying.ResultsBecause the data do not have a nomial distri-bution, we computed the median percentage ofchange in the esophageal column of barium asnieasured by the subjective methods (qualita-tive estimate and measurement of height timesNDFig. 3.-39.year-old woman with achalasia before and after pneumatic dilatation.A-C, Exposure at 1 mm (A), 2 mm (B), and 5 mm (C) before pneumatic dilatation shows partial emptying of barium by 5 mm. Change in pixel count between 1- and 5-mmfilms was 49% and 47%, respectively, for both observers. Change in gross area calculation was 48%, 41%, 47%, and 43% for four observers. Qualitative assessment ofemptying was 40% for each of two observers and 60% for each of two other observers.D-F, Exposure at 1 mm (Dl, 2mm (El, and 5 mm (F) after pneumatic dilatation shows complete emptying of barium by 5mm. On 2-mm film little barium remains in distalesophagus. On 5-mm film this barium has emptied. Change in pixel count, gross area calculation, and qualitative assessment was 100% for all observers. This follow-upstudy was performed with slightly different film-to-patient distance when compared with initial films (A-C). Nonetheless, we can easily estimate esophageal emptying onboth studies and show that definite improvement has occurred.stimates of EsophagealNote-Numbers in parentheses are 9Yoconfidence intervals.aDifferences calculated between quantitative or qualita.tive techniques for estimating esophageal emptying and thegold standard of measuring that emptying (actual percentageof change in pixel count on digitized images).Timed Barium Swallow to Evaluate Esophageal Emptying in AchalasiaAJR:169, August 1997 477the pixel count (Table 1). The mnedian differ-ences between the percentage of change in areaby pixel count and by either quantitative orqualitative assessment of emptying were small:between -7.0% and 2.5% for the four observ-ers. The 95% comifidence intervals for the me-dian difference contain the value zero for allfour observers. indicating no significant differ-ence in the accuracy of either method as com-pared with pixel count (Figs. 2 and 3).For the pixel count, the inter- and intraob-server reliability was almost perfect. and the in-terobserver reliability of height-times-width andqualitative assessments was almnost perfect.DiscussionThe end point in treating patients with achala-sia is to relieve symptoms and achieve esoph-ageal emptying. However. the clinical decisionto stop therapy is usually based on symptomaticrelief alone. This clinical approach assumes thatsymptomatic improvement or relief is associ-ated with physiologic improvement. However.we and others 15-7] have observed that symp-tomatic improvemlient may not accurately reflectoptimal or complete esophageal emptying. Pa-tients with chronic symptoms often subjectivelyinterpret minimiial improvement in esophagealdrainage as dramatic [5. 7. 11 1. This phenorne-non was observed by Eckardt et al. [6], whocompared a detailed score of clinical symptomsbefore and after treatment. Those investigatorsfound that some severely symptomatic patientsmay be satisfied with miinimal improvement andothers may have unrealistic expectations of ther-apy. Holloway et al. I 121 have suggested thatsymptoms in achalasia patients are not related tothe absolute degree of esophageal obstructionbut probably reflect the patients tolerance anddietary adaptations and the degree of loweresophageal sphincter relaxation.Failure to improve esophageal emptying byrelieving the obstructiomi at the lower esoph-ageal sphincter can lead to further deteriorationto the point at which the esophagus becomesnoncompliant and nonfunctional and assumes asigmoid shape. Therefore. some experts treat-ing achalasia patients believe that the end pointof treatment should be complete esophagealemptying [51- This will reduce the degree ofesophageal dilatation. especially in patients witha mild to moderately dilated esophagus. If com-plete emliptying cannot be achieved with mini-mnally invasive therapies. then a Heller sniyotomy should be considered. Because clini-cal evaluation alone is potentially inaccurate inassessing improvement. an objective means ofassessing esophageal emptying is essential indeciding whether to stop or continue treatmentwith methods such as pneumatic dilatation orC. 1)Otllli!lU111 toxin injection.Esophageal scintigraphy is a simple. estab-lished. and objective parameter for evaluatingesophageal emptying [ I 1-16]. The techniqueused in different institutions varies consider-ably. The consistency of the meal may besolid, semisolid. or liquid. The patient may beexamined in the supine or the upright posi-tion. W ater may or may not be ingested afterthe combination of radionuclide and food isswallowed. Lastly. the area of interest mea-sured can change significantly because it isoperator-dependent [ 13]. In addition to thesetechnical variations. esophageal scintigraphyis not widely available. even though it is rela-tively easy to perform. This problem is impor-tant for gastroenterologists who are followingup achalasia patients after pneumatic dilata-lion. Many of these patients are referred byother physicians and live a significant dis-tance from the treating institution. Returningfor follow-up may not be easy for the patients.Although symptom changes can be assessedover the telephone, an objective measure us-ing scintigraphy in medical centers close tothe patient may not be possible.Barium swallow was initially used byVantrappen et al. [7] in achalasia patients to de-termine the cause of persistent symptoms afterpneumatic dilatation. These researchers ob-served that the diameter of the esophagus corre-lated well with the duration of the symptomsand suggested that such a parameter could beimportant in determining the results of pneu-matic dilatation. However, a study described 21years later by Eckardt et al. [6] showed that nocorrelation existed between the reduction inesophageal diameter after pneumatic dilatationand good long-term response based on symp-toms. Cohen [17] suggested that pneumatic di-latation therapy was successful if. the day afterdilatation. the height of the barium columiin wasless than 1 cm above the cardia in the 5-mmfilm after the patient drank 240 ml of bariumsulfate suspension. Lee et al. l J used thistechnique after pneumatic dilatation and ob-served that the test did not correlate with eitherweight gain or relief of dysphagia. W e believethe reason these studies conflict is that symp-toms alone were used as an objective measureof esophageal emptyimig. Further. Cohen I I 7]performed the test only I day after pneumaticdilatation. when considerable edema and spasmmay be present. To avoid postproceduralchanges that may confuse interpretation of ourtimed technique. we wait I miionth after the pro-cedure before assessing esophageal emptying.Recently. Pasricha et al. I 19] described abarium technique for evaluating achalasia pa-tients treated with C. botiiliiiuni toxin injec-lion. After the patient ingests six 10-nilaliquots ofbarium sulfate (70% weight in vol-ume). a single spot film is obtained. Theheight of the barium fluid level above thelower esophageal sphincter and the maximumwidth of the barium column are measured.Additionally. the diameter of the open loweresophageal sphincter is measured. This ap-proach provides a standardized niethod be-cause the volume of barium ingested and themethod of ingestion are consistent. However,because only a single film is obtained. the de-gree of barium retention at only one point intime is assessed.W e believe that a simple timed barium swal-low can adequately assess esophageal emptyingand can be used in any center with a fluoro-scopic unit. The technique we describe is easyto perforni and requires no special equipment.W e have now trained three of our technologiststo perform this study under our supervision.They have had no difficulty successfully com-pleting the examination as described. Further.several of our patients have been examined us-ing this technique after therapy in other institu-tions because the patients could not convenientlyreturn to our medical center. A description ofthe technique was fitxed to the radiologists inthe other institutions. who) were easily able toreplicate the study.This technique is also simple to interpret be-cause both radiologists and gastroenterologistscan accurately assess emptying. Emptying canbe assessed using either the percent change inthe gross area of the esophagus as defined bythe height times width of the barium column ora qualitative estimate ofemptying. Because thequalitative estimate of emptying is as accurateas the change in gross area. is simple. and cande Oliveira et al.478 AJR:169, August 1997be dictated quickly. we now use this as the pre-ferred method of interpretation. Obviously, us-ing an expensive workstation such as the onewe used to analyze digitized films is totally im-practical in a clinical setting. W e used this tech-nique only a s a method to establish a goldstandard for emptying and are not suggestingthat it become routine.In our current study, we did not analyze thesignificance of the ingested barium volume onthe initial and follow-up examinations. For thebaseline study, we allowed the patient tochoose the barium volum e ingested. In our mi-tial experience on follow-up examinations, thepatient again subjectively ingested a tolerablevolume, often different from the volume in-gested for the baseline study. However. ourtechnique has evolved: now. for all subsequentexaminations the patient consumes the samevolum e of barium as ingested for the baselineexamination. W ith a constant volume for fol-low-up. we have a consistent measure of im-provement over baseline.W e occasionally encounter some problemswhen using this technique. Some patientswith achalasia can have a massively dis-tended esophagus. In these patients, theesophagus is so dilated that we cannot fit thebarium column on a three-on-one film, andwe use instead a two-on-one spot film. W henpatients ingest more than 200 ml of barium,the height of the barium column may not fitlengthwise on the film. In these cases, keep-ing the film-to-patient distance constant. weexpose a spot film centered over the lowerportion of the esophagus and follow this filmimmediately with a spot film centered overthe upper portion of the esophagus. W e thenlocate a fixed point on each film (usually avertebral body) that serves as a referencepoint for both films. For qualitative assess-ment. we then judge the degree of emptyingbased on that reference point. If quantitativemeasures are desired, we measure the bariumcolum n above or below that reference pointon the respective films and add the two to es-tim ate the height ofthe entire barium colum n.W hen the esophagus contains retained foodand secretions, a barium-foam interface formsafter the patient ingests the barium. In thesecases, objectively measuring the height of thebarium column may be difficult. W hen a bar-ium-foam interface forms, we measure the su-perior aspect of the barium column at a pointwhere the margin is consistent and reasonablywell defined (Fig. 1). At times, this measure-ment level is arbitrary-one of the reasons weprefer to qualitatively assess emptying. None-theless, if a quantitative assessment is desired,and if the same assumptions for estimating thebarium column height are used for both the1-mm and the 5-mm film, then the estimateof emptying should be accurate. The observerm ust rem em ber that the purpose of the studywas to estimate the degree of esophageal emp-tying on the examination date only. The pres-ence or absence of retained material on acurrent, prior, or subsequent study is irrelevant.For this reason also, keeping the same film-to-patient distance for subsequent follow-up stud-ies is unnecessary (Fig. 3).The last problem we encounter is in patientswith the vigorous form of achalasia. In these pa-tients, forceful, often continuous, nonpropulsivetertiary esophageal contractions occur. As a re-suIt, exposing the spot film when the bariumcolumn is continuous is difficult. Indeed, wehad to exclude one patient in our series becauseof this problem. In these cases, we attempt toexpose the film when the esophagus is relaxed.W e can usually achieve this goal. In our experi-ence. continuous, vigorous esophageal contrac-tions are uncommon in achalasia patients.W e did not correlate esophageal emptyingbased on the timed barium swallow with a sys-tematic, detailed clinical evaluation because wehad an insufficient number of patients evalu-ated before and after therapy ( 12 patients at thetim e of this assessment). Such a study is essen-tial to show the definitive role of our techniquein complementing the clinical examination ofachalasia patients after minimally invasivetreatments. W e are currently following upmore than 30 patients with this technique. 5ev-eral years must pass before we know whetherfollowing objective data gleaned from the bar-ium study after pneumatic dilatation will assistus in determining the choice of further therapy(i.e., further pneumatic dilatation or Hellersmyotomy). Therefore, the purpose of this com-munication was to establish the barium tech-nique and determine the best method ofassessing emptying on the barium study.In conclusion, we have shown that the timedbarium swallow is a simple technique to evalu-ate esophageal emptying. Currently in our insti-tution, all these examinations are performed bytrained technologists. Because no significantdifference in accuracy exists between the quan-titative and the qualitative methods of evalua-tion, we prefer the faster, qualitative method.Our current technique is the same as describedexcept that we use the same volum e of bariumfor both the baseline and the follow-up exami-nations to serve as an internal control. W e be-lieve that this simple technique should be usedas an objective measure of esophageal empty-ing in achalasia patients.ReferencesI. Ferguson M K. Achalasia: current evaluation andtherapy. Ann Thorac Surg 1991:52:336-3422. Couturier D, Samana J. Clinical aspects and man-ometnc criteria in achalasia. Hepatogastroenter-OlO,gV 1991:38:481-4873. Cohen S. M otor disorders of the esophagus. NEngI J M ed 1979:301 :I 84-1924. Parkman HP, Reynolds JC, Ouyang A, Rosato EF.Eisenberg JM , Cohen S. Pneumatic dilation oresophagomyotomy treatment for idiopathic acha-lasia: clinical outcomes and cost analysis. Dig DisSci 1993:38:75-855. Birgisson S. Richter JE. Achalasia: whats new indiagnosis and treatment? Dig Dis 1997:15(suppll):l-276. Eckardt VF, Aignherr C. Bernhard G. Predictorsof outcome in patients with achalasia treated bypneumatic dilation. Gas:roenterologv 1992; 103:1732- 17387. Vantrappen G. Hellemans J, DeloofW , ValemboisP. Vandembroucke J. Treatment of achalasia withpneumatic dilation. Gut 1971; 12:268-2758. Efron B. The jackkimife, the bootstrap a md otherresanmplumg plans. Philadelphia: Society for In-dustrial and Applied Mathematics, 1982:29-359. Fleiss JL. Statistical inetiiodsfor rates and propar-tiOfls. 2nd ed. New York: W iley. 1981:21 1-23610. Landis JR. Koch GG. The measurement of ob-server agreement for categorical data. Biometrics1977:33:159-1741 1 . Robertson CS, Hardy JG, Atkinson M . Quantita-tive assessment of the response to therapy inachalasia of the cardia. Gut 1989:30:768-77312. Holloway RH, Krosion 0, Lange RC, Baue AE,M cCallurn RW . Radionuclide esophageal empty-ing of a solid meal to quantitate results of therapyin achalasia. Gasiroenterologv 1983:84:771-77613. Fisher RS, M almud LS, Applegate G. Rock E,Lorber SH. Effect of bolus composition on esoph-ageal transit: concise communication. J NucI M ed1982:23:878-88214. Rozen P. Gelfond M , Salzman J, Baron J, Gilat 1.Radionuclide confirmation of the therapeutic valueof isosorbide dinitrate in relieving the dysphagia inachalasia. J Cliii Ga.strne,mterol 1982:4:17-22I 5. M cLean RG, Sniart RC, de Carle D. Lau A. Largebolus radionuclide esophageal transit may predictresponse to esophageal dilation in achalasia (let-ter). J Noel M ed 1992:33:205916. Levine M L Dorf BS, M oskowitz G, Bank S. Pneu-matic dilation in achalasia underendoscopic guidance:conn Iation lire- and postdilation by radionuclide scm-tiscan. Am J Gastroenterol 1987:82:3 1 1-314l7. Cohen NN. An end point for pneumatic dilationof achalasia. Gastrointest Endosc 1975:22:2918. Lee JD. Cecil BD, Brown PE, W right RA. TheCohen test does not predict outcome in achalasiaafter pneumatic dilation. Gastrointest Endosc1993:39:157-16019. Pasricha PJ, Ravich W i, Hendrix TR, Sostre 5,Jones B, Kalloo AN. Intrasphincteric botulinumtoxin for the treatment of achalasia. N Eimgl J M ed1995:322:774-778AJR:169, August 1997 479Timed Barium Swallow to Evaluate Esophageal Emptying in AchalasiaAPPENDIX: Summary of Timed Barium Swallow Technique for Assessing Esophageal Emptying in Patients with Achalasia1 . The patient stands.2. The patient ingests lOO-2()O ml of low-density barium (45% weight in volume) over 30-45 sec. with the volume ingested based on patienttolerance. (The same volume of barium is used for follow-up studies.)3. Three-on-one spot films (35 X 35 cm) are obtained I, 2, and 5 mm after ingestion, with the patient in a left posterior oblique position. Thedistance of the fluoroscope carriage from the patient is kept constant for all spot films. The 2-mm film is optional. but fluoroscopy at 2 mmis to determine the state of emptying.4. The degree of emliptying is estimated qualitatively by comparing the 1- and 5-mm films. The degree of emptying may also be estimated bymeasuring the height and width for both films. calculating the rough area for both, and determining the percentage of change in the area(Fig. I).