Radionuclide esophageal transit studies in achalasia before and after balloon dilatation

Pneumatic balloon dilatation is an effective treatment for achalasia. We describe a radionuclide esophageal transit technique to assess and quantify the effectiveness of dilatation. Time-activity curves were generated following ingestion of a 10-ml bolus containing 99Tcm (Technetium-99m) tin colloid. After 30 seconds, the isotope was followed by a 50-ml bolus of water to achieve esophageal washout. Indices calculated included the percentage of retained activity at 30 seconds (B30) and at 100 seconds (B100) and area under the curve. The normal time-activity curve was established in 26 normal volunteers. Transit studies were performed before and after dilatation in 21 patients. Mean B30 fell from 80.9% pre-dilatation to 58.6% post-dilatation and B100 fell from 43.5% to 21.5% pre- and post-dilatation respectively; these compared with a B30 of 6.6% and a B100 of 0% in 26 normal subjects. The area under the curve fell significantly from 4455 s% to 3304 s% compared to 1025 s% in controls. This technique is a simple, reliable method to quantify the effectiveness of treatment in achalasia.