Impedance in the evaluation of the esophagus

Abstract

The aim of this paper is to review esophageal electrical impedance technologies and to discuss the use of these technologies for physiological measurements, diagnostics, and therapy of esophageal disease. In order to develop a better understanding of the pathophysiology of and improve the diagnosis of esophageal disorders, such as gastroesophageal reflux disease (GERD) and achalasia, several new diagnostic tests, including intraluminal impedance, esophageal mucosal impedance, and the functional luminal imaging probe, have been developed. These technologies have proven valuable for assessment of the esophagus in recent years. They provide information on esophageal flow properties, mucosal integrity, lumen shape, and distensibility in esophageal disorders, in particular for GERD and achalasia. Despite their promise and novel clinical studies, the potential of these technologies has been far from realized. New multidisciplinary approaches will contribute to our understanding and interpretation of esophageal impedance data and disease mechanisms.

Novel gel bolus to improve impedance‐based measurements of esophageal cross‐sectional area during primary peristalsis

“…Ultrafast CT scan imaging shows that normal subjects swallow significant amount of air along with the liquid bolus, 13 which we also find based on the US image analysis. Impedance planimetery 10 and functional luminal imaging probe (FLIP) 11,12 are two validated techniques to measure the luminal CSA of the balloon. Two conditions have to be met in order for the impedance methodology to measure the luminal CSA accurately, 1) the conductive medium around the electrodes has to be uniform and of known conductivity, and 2) there should be no leakage of current to the outside of the bolus 22,23 .…”

“…Ultrafast CT scan imaging shows that normal subjects swallow significant amount of air along with the liquid bolus, 13 which we also find based on the US image analysis. Impedance planimetery 10 and functional luminal imaging probe (FLIP) 11,12 are two validated techniques to measure the luminal CSA of the balloon.…”

“…Above has been used successfully in the impedance planimetry 10 and functional luminal imaging probe. 11,12 Kim et al found significant correlation between the Nadir (minimum) impedance values and esophageal luminal CSA during swallow-induced peristalsis. One of the challenges in measuring luminal CSA accurately from intraluminal impedance measurements is the presence of air in the swallowed liquid saline that may have variable effects on Nadir impedance values along the length of the esophagus.…”

“…Based on the Pouillet's Law of electricity, impedance recordings have the potential to reveal the cross‐sectional area (CSA) of conductive materials. Above has been used successfully in the impedance planimetry 10 and functional luminal imaging probe 11,12 . Kim et al found significant correlation between the Nadir (minimum) impedance values and esophageal luminal CSA during swallow‐induced peristalsis.…”

Reconstruction of the human lower esophageal sphincter based on ultra-mill imaging for biomechanical analysis

“…A number of techniques have been applied clinically to diagnose LES disorders. In addition to imaging modalities such as endoscopy, ultrasound, electrical impedance and video-fluoroscopy ( Furlow, 2004 ; Krugmann et al, 2013 ; Wu et al, 2020 ), functional recordings such as pH monitoring have been applied to monitor acid reflux in the LES over an extended period (24 h) ( Mitchell et al, 2001 ). Pressure recordings such as high-resolution manometry involving water-perfused or solid-state pressure sensors provide detailed pressure profiles of esophageal contractions ( Nayar et al, 2005 ; Fox and Bredenoord, 2008 ).…”