New parameter for quantifying bolus transit with high-resolution impedance manometry: A comparison with simultaneous esophagogram.

BACKGROUND: Esophageal bolus transit can be assessed using esophagogram or high-resolution impedance manometry (HRIM). The three-dimensional volume of inverted impedance (VII) has been developed to quantify the residual bolus between each swallow through spatiotemporal analysis. However, this novel metric has not been validated against simultaneous esophagogram. METHODS: A total of nine healthy volunteers (Seven males, aged 19-45 years) were prospectively evaluated with HRIM and barium esophagogram. In addition, 21 symptomatic patients (12 males, aged 20-85 years) without major motility disorder were also included. The VII was estimated from HRIM data using MATLAB program and was compared with residual bolus volume in the esophagus estimated from simultaneous esophagogram. KEY RESULTS: A total of 80 swallows (24 in controls and 56 in patients) were analyzed. Results from the VII method were concordant with the bolus transit pattern estimated from the esophagogram in 91.3% (73/80) of swallows. The correlation between quantitative data from VII and the volume of residual bolus estimated from esophagogram was strong in both groups with a Pearson's correlation coefficient of 0.805 for healthy volunteers and 0.730 for symptomatic patients. The intraclass correlation coefficient of VII between the three swallows within a subject was 0.901 in healthy subjects and 0.705 in patients, indicating a modest reliability of this method. CONCLUSIONS AND INFERENCES: The newly developed VII method is a reliable method in assessing residual bolus volume in the esophagus based on comparison with bolus volume estimated from simultaneous esophagogram.