Assessment of colorectal length using the electromagnetic capsule tracking system: a comparative validation study in healthy subjects.

AIM: We aimed to determine colorectal length with the 3D-Transit system by describing a 'centreline' of capsule movement and comparing it with known anatomy, as determined by magnetic resonance imaging (MRI). Further, we aimed to test the day-to-day variation of colorectal length assessed with the system. METHOD: The 3D-Transit system consists of electromagnetic capsules that can be tracked as they traverse the gastrointestinal tract. Twenty-five healthy subjects were examined with both 3D-Transit and MRI. Another 21 healthy subjects were examined with 3D-Transit on two consecutive days. RESULTS: Computation of colorectal length from capsule passage was possible for 60 of the 67 3D-Transit recordings. The length of the colorectum measured with MRI and 3D-Transit was 95 (75-153) cm and 99 (77-147) cm, respectively (P = 0.15). The coefficient of variation (CV) between MRI and 3D-Transit was 7.8%. Apart from the caecum/ascending colon being 26% (P = 0.002) shorter on MRI, there were no other differences in total or segmental colorectal lengths between methods (all P > 0.05). The length of the colorectum measured with 3D-Transit on two consecutive days was 102 (73-119) cm and 103 (75-123) cm (P = 0.67). The CV between days was 7.3%. CONCLUSION: The 3D-Transit system allows accurate and reliable determination of colorectal length compared with MRI-derived colorectal length and between days. Antegrade or retrograde capsule movement relative to this centreline, as well as the length and speed of movements, may be determined by future studies to allow better classification and treatment in patients with dysmotility.

Regional gastrointestinal transit times in severe ulcerative colitis.

BACKGROUND: Gastrointestinal (GI) dysmotility may present secondary to inflammatory bowel disease. The main aim of this study was to investigate GI motility in ulcerative colitis (UC) patients during severe disease activity. METHODS: Twenty patients with severe UC were studied with a novel telemetric capsule system (3D-Transit) designed for minimally invasive, ambulatory assessment of total and regional GI transit times. Ten patients were available for follow-up during remission. Data were compared to those of 20 healthy subjects (HS). KEY RESULTS: Total GI transit time was significantly longer in patients with severe UC (median 44.5 h [range 9.9-102.7 h]) than in HS (median 27.6 h [range 9.6-56.4 h]) (p = 0.032). Additionally, during severe UC, transit time was prolonged through the proximal colon (p = 0.003) and there were strong trends toward longer than normal small intestinal transit time (HS: median 4.9 h [range 3.4-8.3 h] vs severe UC patients: median 5.9 h [range 3.9-11.9 h]; p = 0.053) and colorectal transit times (HS: median 18.2 h [range 1.5-43.7] vs severe UC patients: median 34.9 h [range 0.4-90.9 h]; p = 0.056). Our data further indicate that total GI and colorectal transit times may be prolonged in UC during early remission. CONCLUSIONS & INFERENCES: Total GI transit times are significantly prolonged during severe UC.

Pilot study trialling a new ambulatory method for the clinical assessment of regional gastrointestinal transit using multiple electromagnetic capsules.

BACKGROUND: Gastrointestinal (GI) motor disorders often involve several regions of the GI tract. Therefore, easy and safe assessment of whole gut and regional motility is valuable for more precise diagnosis. 3D-Transit is a novel method for ambulatory evaluation of total and regional gastrointestinal transit times (GITT) based on the anatomical localization of ingestible electromagnetic capsules. The main purpose of this study was to test the performance of the 3D-Transit system. METHODS: Twenty healthy volunteers each ingested three electromagnetic capsules over a period of two consecutive days. Standard radio-opaque markers (ROM) were also ingested to assess the agreement between total GITT obtained with both methods. KEY RESULTS: Investigations were well-tolerated and three capsules could be tracked simultaneously with minimal data loss (Capsule 1: median: 0.2% of time (range 0-25.3%). Region specific contraction patterns were identified and used for computation of total and regional GITT in all subjects. Inter-observer agreement was 100% for total GITT (median variation 0%) but less for regional GITT. Day-to-day and diurnal variations were significant for total and regional GITT. Total GITT assessed by 3D-Transit capsules were moderately well-correlated to those assessed with standard ROM (Spearman's rho = 0.7). CONCLUSIONS & INFERENCES: 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.

Turning off sacral nerve stimulation does not affect gastric and small intestinal motility in patients treated for faecal incontinence.

AIM: Sacral nerve stimulation (SNS) reduces symptoms in up to 80% of patients with faecal incontinence (FI). Its effects are not limited to the distal colon and the pelvic floor. Accordingly, spinal or supraspinal neuromodulation have been suggested as part of the mode of action. The effect of SNS on gastric and small-intestinal motility was studied. METHOD: Using the magnet tracking system, MTS-1, a small magnetic pill was tracked twice through the upper gastrointestinal tract of eight patients with FI successfully treated with SNS. Following a randomized double-blind crossover design, the stimulator was either left active or was turned off for 1 week before investigations with MTS-1. RESULTS: The median (range) frequency of gastric con-tractions was 3.05 (2.83-3.40) per min during SNS and 3.04 (2.79?-3.76) per min without (P=NS). The median (range) frequency of contractions in the small intestine during the first 2h after pyloric passage was 10.005 (9.68-10.70) per min during SNS and 10.09 (9.79-10.29) per min without SNS (P=NS). The median (range) velocity of the magnetic pill during the first 2h in the small intestine was 1.6 (1.2-2.8) cm/min during SNS and 1.7 (0.8-3.7) cm/min without SNS (P=NS). Small-intestinal propagation mainly occurred during very fast movements (>15cm/min), accounting for 51% (42-60%) of the distance 3% (2-4%) of the time during SNS and for 53% (18-73%) of the distance 3% (1-8%) of the time without SNS (P=NS). CONCLUSION: Turning off SNS for 1week did not affect gastric or small-intestinal motility patterns.

Gastric and small intestinal dysfunction in spinal cord injury patients.

BACKGROUND: Many patients with spinal cord injury (SCI) suffer from constipation, abdominal pain, nausea, or bloating, and colonic transit times are prolonged in most. Gastric and small intestinal dysfunction could contribute to symptoms but remain to be described in detail. Also, it is obscure whether the level of SCI affects gastric and small intestinal function. AIM: To study orocecal transit time and gastric emptying (GE) in patients with SCI. METHODS: Nineteen patients with SCI (7 ♀, median age 54 years) and 15 healthy volunteers (9 ♀, median age 32 years) were included. All were referred because of neurogenic bowel problems. Eleven patients had low SCI (located at conus medullaris or cauda equina) affecting only the parasympathetic nerves to the left colon and eight had high SCI (above Th6) affecting parasympathetic and sympathetic innervation. Subjects ingested a small magnetic pill that subsequently was tracked by the Motility Tracking System - MTS-1 (Motilis, Lausanne, Switzerland). RESULTS: Orocecal transit time was longer than normal both in individuals with high lesions (P < 0.01) and in individuals with low lesions (P < 0.01). Individuals with high lesions had slower GE than those with conal/cauda equina lesions (P < 0.05). Basic contractile frequencies of the stomach and small intestine were unaffected by SCI. CONCLUSION: Surprisingly, upper gastrointestinal transit is prolonged in subjects with SCI suffering from bowel problems, not only in subjects with cervical or high thoracic lesions but also in subjects with conal/cauda equina lesions. We speculate that this is secondary to colonic dysfunction and constipation.

Colonic movements in healthy subjects as monitored by a Magnet Tracking System.

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.

Electrical stimulation induces propagated colonic contractions in an experimental model.

BACKGROUND: Direct colonic electrical stimulation may prove to be a treatment option for specific motility disorders such as chronic constipation. The aim of this study was to provoke colonic contractions using electrical stimulation delivered from a battery-operated device. METHODS: Electrodes were inserted into the caecal seromuscular layer of eight anaesthetized pigs. Contractions were induced by a neurostimulator (Medtronic 3625). Caecal motility was measured simultaneously by video image analysis, manometry and a technique assessing colonic transit. RESULTS: Caecal contractions were generated using 8-10 V amplitude, 1000 micros pulse width, 120 Hz frequency for 10-30 s, with an intensity of 7-15 mA. The maximal contraction strength was observed after 20-25 s. Electrical stimulation was followed by a relaxation phase of 1.5-2 min during which contractions propagated orally and aborally over at least 10 cm. Spontaneous and stimulated caecal motility values were significantly different for both intraluminal pressure (mean(s.d.) 332(124) and 463(187) mmHg respectively; P < 0.001, 42 experiments) and movement of contents (1.6(0.9) and 3.9(2.8) mm; P < 0.001, 40 experiments). CONCLUSION: Electrical stimulation modulated caecal motility, and provoked localized and propagated colonic contractions.

Magnet Tracking: a new tool for in vivo studies of the rat gastrointestinal motility.

Digestive motility was studied in the rat using a miniaturized version of the Magnet Tracking system which monitored the progression of a small magnetic pill through the entire digestive tract. The dynamics of movement was followed and three-dimensional (3-D) images of digestive tract were generated. After a retention period in the stomach and rapid passage through duodenum, the magnet progressed along the small intestine with gradually decreasing speed and longer stationary periods. It remained in the caecum for variable intervals. In the colon, periods of progress alternated with long quiescent periods. Gastric activity oscillated at 5-6 min(-1). In the small intestine, two frequency domains coexisted, showing independent modulations and proximo-distal gradients (40 to >32 and 28 to >20 min(-1)). Caecal oscillations were of 1.5 min(-1). The data allowed the magnet location and calculation of gastric and small intestinal transit times (58 +/- 36 and 83 +/- 14 min respectively), both significantly prolonged by oleate administration (243 +/- 130 and 170 +/- 45 min respectively). Magnet Tracking is a non-invasive tool to study the in vivo spatial and temporal organization of gastrointestinal motility in the rat.

Magnetic pill tracking: a novel non-invasive tool for investigation of human digestive motility.

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.