Mucosal Impedance Spectroscopy for Objective Real-time Assessment of Mucosal Health

Abstract

Background and AimsThere is a need for a real-time objective tool to assess the mucosal health of the gastrointestinal (GI) tract during endoscopy. Our aim was to develop, design, and validate a low-cost mucosal impedance (MI) device and determine its role in differentiating diseased mucosa from normal mucosa. MethodsA biocompatible catheter was designed and developed after multiple iterations. It was validated with a commercially available catheter and histopathological analysis in a blinded manner. Patients undergoing resection of the GI tract were recruited after consent, and the resected specimens were analyzed ex vivo for MI within 10 minutes of resection. An average of 3 MI readings of the visually diseased segment and adjacent normal segment were analyzed. MI values of diseased and non-diseased mucosa were compared. ResultsThe in-house catheter was validated with a commercially available impedance measuring device. It showed a high degree of positive correlation (rho = 0.616; P < 0.001). Two hundred and thirty-two patients (age 46 ± 15 years; 68% females) (180 inflammatory and 52 malignant pathology) who were undergoing abdominal surgery were enrolled. The median impedance value of diseased segments was significantly lower than that of the adjacent normal segments of gut in 130 paired samples [1832(727)Ω vs 2604(1295)Ω; P < 0.001]. The MI value of segments containing malignant tissue (n = 50) and inflamed tissue (n = 80) was significantly lower than the MI value of adjacent normal segments of the GI tract [1880(977)Ω vs 2583(1431)Ω; P < 0.001 and 1787(557)Ω vs 2515(1244)Ω; P < 0.001, respectively]. There was a 24% reduction in visually diseased segments [median reduction 712(661)Ω] from adjacent normal segments. A biocompatible endoscopic catheter (3-mm diameter) has been developed and tested in 3 patients and was found to differentiate diseased from normal mucosa. ConclusionImpedance spectroscopy is an effective real-time, simple, objective tool to differentiate diseased gut mucosa from healthy mucosa.