Changes in Esophageal Transit Scintigraphy After Peroral Endoscopic Myotomy in Patients With Achalasia

Background/Aims: Esophageal transit scintigraphy is a non-invasive nuclear medicine imaging modality for people with esophageal transit problems.In particular, changes in esophageal motor function can be evaluated non-invasively before and after the treatment in patients undergoing peroral endoscopic myotomy (POEM) for achalasia.This study compared the changes in several parameters of esophageal transit and manometry in patients with achalasia who underwent POEM.Methods: This study retrospectively analyzed prospectively collected data from POEM participants.We included 38 patients with achalasia who underwent high-resolution manometry and esophageal transit scintigraphy before POEM and after POEM from 2016 to 2023.Results: All patients had clinical treatment successfully (Eckardt score < 3).Lower esophageal sphincter (LES) pressures were significantly reduced after POEM, including basal resting LES pressure and integrated relaxation pressure (P < 0.001).Esophageal emptying, as assessed by the residual fraction of retained radioactivity at 10 seconds after isotope ingestion, improved from 54.3% to 27.3% (P < 0.001).Analysis of the change in time-to-peak on the time-radioactivity curve showed that it shortened significantly in the upper and middle portions of the esophagus (P < 0.05) but not in the lower portion.The Eckardt symptom score significantly correlated with pre-POEM integrated relaxation pressure (P < 0.05).Post-PO-EM, the symptom score significantly correlated with time-to-peak of the upper portion of the esophagus (P < 0.05).Conclusions: Patients with achalasia who received POEM showed improved not only manometric LES parameters but also esophageal transit.Analysis of the radiation curve's time-to-peak showed that improved retention in the upper portion is an indicator of symptoms improvement in patients who underwent POEM.