3D-transit is a well-tolerated and minimal invasive ambulatory method for assessment of GI motility. By providing both total and regional transit times, the 3D-Transit system holds great promise for future clinical studies of GI function in health and disease.

BackgroundTracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system.MethodsA small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4) giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, ϕ). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state.ResultsExperiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1) (p = 0.03).ConclusionMTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

The Magnet Tracking System (MTS) is a minimally-invasive technique of continuous evaluation of gastrointestinal motility. In this study, MTS was used to analyse colonic propulsive dynamics and compare the transit of a magnetic pill with that of standard radio-opaque markers. MTS monitors the progress in real time of a magnetic pill through the gut. Ten men and 10 women with regular daily bowel movements swallowed this pill and 10 radio-opaque markers at 8 pm. Five hours of recordings were conducted during 2 following mornings. Origin, direction, amplitude and velocity of movements were analysed relative to space-time plots of the pill trajectory. Abdominal radiographs were taken to compare the progress of both pill and markers. The magnetic pill lay idle for 90% of its sojourn in the colon; its total retrograde displacement accounted for only 20% of its overall movement. Analysis of these movements showed a bimodal distribution of velocities: around 1.5 and 50 cm min(-1), the latter being responsible for 2/3 of distance traversed. There were more movements overall and more mass movements in males. Net hourly forward progress was greater in the left than right colon, and greater in males. The position of the magnetic pill correlated well with the advancement of markers. MTS showed patterns and propulsion dynamics of colonic segments with as yet unmet precision. Detailed analysis of slow and fast patterns of colonic progress makes it possible to specify the motility of colonic segments, and any variability in gender. Such analysis opens up promising avenues in studies of motility disorders.

The 3D-Transit system now allows detailed description of colonic motility and our results are supported by those previously suggested by manometry. It holds promise for future assessment of movement patterns to characterize different diseases and effects of treatment.

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A new minimally invasive technique allowing for anatomical mapping and motility studies along the entire human digestive system is presented. The technique is based on continuous tracking of a small magnet progressing through the digestive tract. The coordinates of the magnet are calculated from signals recorded by 16 magnetic field sensors located over the abdomen. The magnet position, orientation and trajectory are displayed in real time. Ten young healthy volunteers were followed during 34 h. The technique was well tolerated and no complication was encountered. The information obtained was 3-D configuration of the digestive tract and dynamics of the magnet displacement (velocity, transit time, length estimation, rhythms). In the same individual, repeated examination gave very reproducible results. The anatomical and physiological information obtained corresponded well to data from current methods and imaging. This simple, minimally invasive technique permits examination of the entire digestive tract and is suitable for both research and clinical studies. In combination with other methods, it may represent a useful tool for studies of GI motility with respect to normal and pathological conditions.

Background The 3D‐Transit electromagnet tracking system (Motilis Medica, SA, Lausanne, Switzerland) is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit and motility. Using this tool, we aimed to derive normative values for region‐specific colonic and GI transit times and to assess the influence of age, gender, and body mass index (BMI). Methods Regional and total colonic transit times (CTT), gastric emptying (GET), small intestinal (SITT), and whole gut (WGTT) transit times were extracted from 111 healthy volunteers from the United Kingdom and Denmark (58 female; median age: 40 years [range: 21‐88]). The effects of age, gender, and BMI were assessed using standard statistical methods. Key Results The ascending, transverse, descending, and rectosigmoid colon transit times accounted for 32%, 34%, 17%, and 17% of total CTT in females, and 33%, 25%, 14%, and 28% of total CTT in males. CTT and WGTT were seen to cluster at intervals separated by approximately 24 hours, providing further evidence of the non‐continuous nature of these measurements. Increasing age was associated with longer CTT (P = .021), WGTT (P < .001) ascending (P = .004), transverse (P < .001), and total right (P < .001) colon transit times, but shorter rectosigmoid (P = .004) transit time. Female gender was significantly associated with longer transverse (P = .049) and descending (P < .001) colon transit times, but shorter rectosigmoid (P < .001) transit time. Increasing BMI was significantly associated with shorter WGTT (P = .012). Conclusions and Inferences For the first time, normative reference values for region‐specific colonic transit have been presented. Age, gender, and BMI were seen to have an effect on transit times.

Background/AimsThe paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea restricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients' regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. MethodsFifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were investigated with 3D-Transit and standard radiopaque markers. ResultsTotal GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman's rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5-47.2) hours in patients versus 25.1 (range: 13.1-142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4-5.5) hours in patients versus 4.4 (range: 1.8-7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9-40.1) hours in patients versus 18.1 (range: 5.0-134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental colonic movements was 0.45 (range: 0.03-1.02) per hour in patients and 0.07 (range: 0-0.61) per hour in healthy subjects (P = 0.045). ConclusionsThree-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have