TIMED BARIUM SWALLOW - A SIMPLE TECHNIQUE FOR EVALUATING ESOPHAGEAL EMPTYING IN PATIENTS WITH ACHALASIA

OBJECTIVE. Our purpose was to define a simple technique for timing a b arium swallow by which radiologists can assess esophageal emptying in patients with achalasia before and after minimally invasive therapy. O ur purpose was also to determine the best method of quantifying the de gree of emptying using this timed technique. MATERIALS AND METHODS. In the barium swallow technique, upright frontal spot films of the esoph agus are obtained at 1, 2, and 5 min after ingestion of 100-200 ml of low-density (45% weight in volume) barium sulfate (volume of barium de termined by patient tolerance). Forty-two of these barium swallows don e by 23 patients with achalasia were retrospectively reviewed. The exa mination served either as a baseline study or as a 1-month follow-up s tudy after patients had undergone pneumatic dilatation or Clostridium botulinum toxin injection, The spot films were digitized, and a region of interest was drawn around the column of barium by two observers, T he change in area seen in the region of interest on the 1- and 5-min f ilms served as the gold standard for percentage of emptying. The spot films were then analyzed by four other observers, each of whom indepen dently, subjectively, and qualitatively estimated the percentage of em ptying between the 1- and 5-min spot films, Percentages were divided i nto quintiles. On a separate occasion, each of these four observers al so independently measured the height and width of the barium column on the 1- and 5-min spot films, The product of height times width seen o n the 1- and 5-min films became the quantitative estimate for percenta ge of emptying. RESULTS. We found no statistically significant differe nce between the percentage of emptying as measured on the digitized im ages by the two observers and the height-times-width calculations or q ualitative emptying percentage as estimated by the four observers. Int erobserver agreement for the area evaluated on the digitized films as well as the height-times-width measurements and qualitative estimates of emptying was almost perfect (the correlation coefficients being 0.9 9, 0.87, and 0.93, respectively). CONCLUSION. The timed barium swallow is a simple and reproducible technique, Both qualitative assessment a nd estimated change in area based on height-times-width measurements o i the barium column are accurate methods of estimating esophageal empt ying.