Inter‐ and intra‐rater agreement of interpretation of functional lumen imaging probe in healthy subjects

Abstract

Background

The functional lumen imaging probe (FLIP) evaluates esophagogastric junction (EGJ) opening and esophageal contractility. Both post hoc and real‐time analyses are possible, but reproducibility and reliability of analysis remain undefined. This study assesses inter‐ and intra‐rater agreement of normative FLIP measurements among novice and experienced users.

Methods

Eight motility experts from different institutions independently evaluated de‐identified video recordings from 27 asymptomatic healthy subjects using FLIP. Interpretation methods simulating a post‐procedure and a live procedure setting were tested. Novice FLIP users ( n = 3) received training prior to post‐procedure interpretation. Experienced FLIP users ( n = 5) interpreted using both methods. Users recorded maximum EGJ and distal esophageal body diameter, distensive pressure, and EGJ distensibility index (EGJ‐DI), at balloon fill volumes of 50‐, 60‐, and 70 ml, as well as repetitive antegrade contractions (RACs). Inter‐ and intra‐rater agreements of diameters, distensive pressure and EGJ‐DI were assessed by intra‐class correlation coefficient (ICC) and Pearson's correlation coefficient (PCC). Percentage agreement evaluated inter‐ and intra‐rater reliability for RACs.

Key Results

Novice and experienced users acquired normative FLIP metrics. Good‐to‐excellent inter‐ and intra‐rater reliability were achieved for all variables at 60 ml balloon fill volumes. Median parameters at 60 ml balloon fill volume were as follows: EGJ‐DI 5.5 mm ²/mmHg, maximum EGJ diameter 18.6 mm, distensive pressure at maximum EGJ diameter 48.1 mmHg, and distal esophageal body diameter 19.5 mm.

Conclusions and Inferences

Normative FLIP parameters can be reliably extracted from FLIP videos using both real‐time and post hoc analyses, with high reliability between experienced and novice users.