Timed-barium esophagogram (TBE) is established test for assessing bolus clearance in achalasia post-treatment. However, radiation exposure is an important disadvantage. Esophageal bolus transit can be evaluated by HRIM. Previous studies comparing Impedance bolus height (IBH) using saline and TBE showed fair correlation. We compared bolus clearance by TBE versus HRIM using yogurt (viscosity matched to barium—calculated using Ostwald viscometer) in patients treated for achalasia. HRIM was performed using solid-state system (MMS, Netherlands). Twenty patients (age 45.1 years; 8 men) treated with pneumatic dilatation (Rigiflex, Boston Scientific) were evaluated with TBE (200 ml Barium) and HRIM (200 ml yoghurt) two weeks after dilation. Both tests were performed in upright position. Barium column height and impedance bolus height (IBH) were measured at 0, 1 and 5 min. Analysis of IBH was performed with spatial impedance variation plot overlayed on esophageal pressure topography. All patients gave consent, and protocol was approved by the IRB. At baseline, 5, 11 and 4 patients had type I, II and III achalasia, respectively. Eckardt score showed an improvement of 5 (range 1–9) points. The mean column height as measured by IBH and TBE at 5 min was similar (4.6 range 0–12.5 cm vs. 4.25 0–16 cm). Pearson correlation between the TBE column and IBH was 0.73 at 5 min. Bland Altman plot for bolus clearance as measured by TBE and HRIM showed good agreement between the modalities. There is good agreement between HRIM (performed using yoghurt) and TBE for evaluation of bolus clearance after therapy in achalasia patients. Single HRIM study done with viscosity matched liquid to barium can give information about bolus clearance and motor function in treated achalasia patients, avoiding radiation exposure.
Karad et al. (Mon,) studied this question.