Assessment of Gastrointestinal Transit Time Using Video Capsule Endoscopy

Abstract

Purpose: Video capsule endoscopy (VCE) is a procedure that uses a wireless camera to take pictures of the gastrointestinal tract. This is most frequently used for evaluating obscure gastrointestinal bleeding. A wireless motility capsule (WMC) of a similar size has been developed, which measures pH, pressure, and temperature, and can be used to assess regional and total gastrointestinal transit times. VCE could also potentially be used as a tool for measuring GI transit time, but here is limited data on gastric empying time (GET) and small bowel transit time (SBTT) using VCE and normal ranges are not standardized.Table: [1726] GET and SBTT as determined by video capsule endoscopy (VCE) compared with wireless motility capsule (WMC) dataMethods: In order to obtain GI transit data and compare results of VCE with those of WMC, we did a retrospective study using data from VCE (PillCam, Given Imaging) performed between 2003-2007 in a county hospital setting. Patients were included if the indication for VCE was either iron deficiency anemia (IDA) or overt obscure GI bleed (OOGIB) and they had no known motility disorder. GET and SBTT (median with 25th-75th percentile) were compared between groups. Results from VCE were also compared with those from healthy controls who were studied with the WMC (SmartPill). Results: There were a total of 147 VCE studies performed, including 42 for OOGIB and 105 for IDA. Mean age (±SD) in the total group was 57.9 ±14.2, 94 (64%) were female, and 135 (92%) were Hispanic. The VCE did not reach the duodenum by the end of the study in 8 of 147 patients (5.4%), so these results were not included in the analysis. Using a linear regression analysis, age and gender had no significant effect on GET. There was a weak inverse linear association between GET and SBTT (r=0.19, p< 0.04). GET and SBTT in the IDA group was not significantly different compared with the OOGIB group. However, GET and SBTT were significantly faster in both groups when compared with WMC data as the gold standard for measuring GI transit time. The table outlines values for patients with OOGIB, IDA, total VCE studies, and 66 healthy controls in WMC studies. Conclusion: 1) GET and SBTT using VCE is not significantly different in OOGIB compared with IDA. 2) Both GET and SBTT are significantly faster in VCE compared with WMC measurements. This is mainly explained by differences in methods of preparation, with VCE performed in the fasting state when phase III migratory motor complexes regularly sweep the GI tract, while WMC is performed after a standardized solid meal where migratory motor complexes are delayed until the digestible solid food is emptied. In summary, VCE could potentially be used for measuring GI transit time in the fasting state and we provide new criteria for normal GET and SBTT.