Breath Analysis Using eNose and Ion Mobility Technology to Diagnose Inflammatory Bowel Disease—A Pilot Study

Abstract

Early diagnosis of inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), remains a clinical challenge with current tests being invasive and costly. The analysis of volatile organic compounds (VOCs) in exhaled breath and biomarkers in stool (faecal calprotectin (FCP)) show increasing potential as non-invasive diagnostic tools. The aim of this pilot study is to evaluate the efficacy of breath analysis and determine if FCP can be used as an additional non-invasive parameter to supplement breath results, for the diagnosis of IBD. Thirty-nine subjects were recruited (14 CD, 16 UC, 9 controls). Breath samples were analysed using an in-house built electronic nose (Wolf eNose) and commercial gas chromatograph–ion mobility spectrometer (G.A.S. BreathSpec GC-IMS). Both technologies could consistently separate IBD and controls [AUC ± 95%, sensitivity, specificity], eNose: [0.81, 0.67, 0.89]; GC-IMS: [0.93, 0.87, 0.89]. Furthermore, we could separate CD from UC, eNose: [0.88, 0.71, 0.88]; GC-IMS: [0.71, 0.86, 0.62]. Including FCP did not improve distinction between CD vs UC; eNose: [0.74, 1.00, 0.56], but rather, improved separation of CD vs controls and UC vs controls; eNose: [0.77, 0.55, 1.00] and [0.72, 0.89, 0.67] without FCP, [0.81, 0.73, 0.78] and [0.90, 1.00, 0.78] with FCP, respectively. These results confirm the utility of breath analysis to distinguish between IBD-related diagnostic groups. FCP does not add significant diagnostic value to breath analysis within this study.

Detection of Group B Streptococcus in pregnancy by vaginal volatile organic compound analysis: a prospective exploratory study

“…The data was analysed using the statistical pipeline successfully used in [16][17][18]. In summary, the GC-IMS data was first extracted using the L.A.V.…”

“…Here a Gas Chromatograph-Ion Mobility Spectrometer (GC-IMS) was used. Our group have previously used this instrument on a range of medical conditions including respiratory tract infections, Coeliac's disease and irritable bowel disease [16][17][18]. This instrument was chosen over more traditional gas chromatograph mass spectrometer (GCMS) as the basic sensitivity of the instrument is much higher than GCMS, it can use nitrogen/air as the carrier gas (so no need for expensive carrier gases such as helium), has a lower purchase/test cost than GCMS and has a much smaller form factor, making it applicable for a ward setting.…”

Hybrid Analytical Platform Based on Field-Asymmetric Ion Mobility Spectrometry, Infrared Sensing, and Luminescence-Based Oxygen Sensing for Exhaled Breath Analysis

“…Only a few research groups have selected this path for exhaled breath analysis. The probably most commonly selected approach is the use of electronic noses [5][6][7][8][9][10], i.e. arrays of different colorimetric [8] or metal oxide sensors [9] individually responding to different types of molecules.…”

“…Consequently, truly orthogonal methods are based on different physical principles generating the analytical signals, yet applied to the same sample. This approach has already been proposed [14,15] and put into practice [10,[16][17][18][19][20] by various research groups. For example, Covington et al [10] applied an eNose and GC-IMS to the same breath samples, whereas Williams et al [19] parallely used non-dispersive infrared analysis and PTR-TOF-MS on the same sample set.…”

“…This approach has already been proposed [14,15] and put into practice [10,[16][17][18][19][20] by various research groups. For example, Covington et al [10] applied an eNose and GC-IMS to the same breath samples, whereas Williams et al [19] parallely used non-dispersive infrared analysis and PTR-TOF-MS on the same sample set. It is important to notice though that all above-mentioned groups except Monks et al [20] applied different analytical methods as standalone-techniques, i.e.…”