Measurement Of Colonic Transit Research Articles

Expanding criteria for slow colonic transit in patients being evaluated for chronic constipation by scintigraphy.

Colonic transit measurement [geometric center (GC) at 24 and 48hours] identifies slow transit constipation (STC) in patients with chronic constipation. To evaluate the utility of the difference between GC24 and GC48 (Δ48-24 ) to identify STC in adults with chronic constipation. We reviewed medical records of 250 patients, aged 18-75years, who underwent colonic transit by scintigraphy during 1994-2019 for investigation of chronic constipation. Data collected included demographics, medical and surgical histories, and anorectal manometry. We used colonic transit from 220 healthy controls to identify the 5th percentile for diagnosing STC: 1.3 at 24hours, and 1.9 at 48hours. In addition, the 5th percentile for Δ48-24 was 0.38 for females and 0.29 for males. Data are reported as median and IQR [Q1, Q3]). Among the 250 patients [median age 42.5 years (IQR 30.75, 56), 84% female], based on GC24<1.3, 52 (20.8%) had STC (3 males, 49 females); and based on GC48<1.9, 28(11.2%) had STC (3 males, 25 females). Colonic transit was normal in 74.8%. In the groups with normal GC24 and GC48, Δ48-24 identified an additional 32(15.1%) of 212 female patients and 4 (10.5%) of 38 male patients with slow progression of colonic transit between 24 and 48hours. Among these 36 patients with abnormal Δ48-24 , 13(36.1%) had evidence of rectal evacuation disorder. Δ48-24 measurement on scintigraphic colonic transit can identify an additional 9.2% of STC in patients with constipation without rectal evacuation disorder and can help individualize treatment of chronic constipation.

Slow Transit Constipation

Slow transit constipation is a rare condition that is almost exclusively encountered in middle-aged women. The pathophysiology and aetiology are poorly understood, but a multi-factorial pathogenesis seems likely. In the course of the differential diagnosis, mechanical, drug-induced, degenerative, metabolic, endocrinological, neurological and psychiatric causes of constipation must be excluded by an interdisciplinary approach. Gastrointestinal physiological investigations are mandatory, including measurement of colonic transit. Furthermore, pangastrointestinal transit delay, pelvic floor dysfunction and irritable bowel syndrome should be excluded. The initial mode of treatment is strictly conservative. In cases of progression or persistence of symptoms, surgical therapy should be discussed. Subtotal colectomy with ileorectal anastomosis can be regarded as the standard operation for slow transit constipation. Postoperative complications include small bowel obstruction, incontinence and persistence or recurrence of constipation and/or abdominal pain. Using strict criteria for patient selection, overall success rates are reported in excess of 80%.

A single-center, prospective, double-blind, sham-controlled, randomized study of the effect of a vibrating capsule on colonic transit in patients with chronic constipation.

In an open-label study of 26 patients with IBS-C and chronic constipation, treatment with a vibrating (VIBRANT) capsule twice a week for 7.5weeks resulted in 88.5% responders. Effects on colonic transit are unclear. We aimed to compare effects of VIBRANT and sham capsule treatment on colonic transit in patients with functional constipation. Patients with functional constipation (Rome III criteria) were randomized to VIBRANT or sham capsule treatment for 8weeks and underwent scintigraphic colonic transit measurements during week 8. We estimated the overall rate of colonic transit from the slope of progression of colonic geometric center over 48hours. The capsule was activated 8hours after ingestion, and the vibration sequence included 240 cycles. There were no significant group differences in overall colonic transit [GC48, 2.76 (IQR 2.42-4.03) for sham group and 3.46 (2.55-4.61) for active treatment group (P=.13)]. Additionally, the progression of the isotope through the colon was numerically faster, though not significantly different (slope, P=.14) in the VIBRANT capsule group compared to the sham group. Three participants in the VIBRANT capsule group had accelerated colonic transit at 32hours and faster colonic transit slope compared to the 95th percentile of the sham group. Although there were no group differences between VIBRANT and sham capsule treatment on colonic transit, at least one (and possibly three) of 12 patients receiving the VIBRANT capsule had faster colonic transit. The vibration parameters to accelerate colonic transit in patients with functional constipation require further optimization.

Review article: biomarkers and personalised therapy in functional lower gastrointestinal disorders.

Treatment of IBS and functional lower gastrointestinal disorders is still based predominantly on symptoms; biomarkers that reflect the mechanism or pathophysiology have been identified. Given the diverse mechanisms that result in the same clinical phenotype of IBS, it is hypothesised that identification of biomarkers may lead to individualisation of medical therapy. To review the biomarkers that have been appraised in IBS. A single author reviewed the published literature on biomarkers appraised in IBS. The current literature suggests that these biomarkers are insufficiently sensitive or specific to differentiate IBS from health or from other diseases causing similar symptoms, such as coeliac disease or inflammatory bowel disease. Most of the proposed biomarkers are not actionable, that is, they do not lead to an efficacious therapy based on the biological inference of the biomarker itself. However, among proposed biomarkers in IBS, some are actionable, as they specifically reflect a quantitative difference in a mediator of dysfunction or result in a quantifiable disturbance of function that can be specifically treated. Such biomarkers may potentially identify relevant subgroups that respond to specific therapy. The most promising actionable biomarkers are measurement of colonic transit (leading to treatments that reverse the abnormal transit) and measurements of bile acid diarrhoea to identify responders to bile acid sequestrants. Therefore, although biomarkers are not ready for prime time as diagnostic tests in IBS, some biomarkers could identify subgroups of patients with IBS for inclusion in clinical trials that target specific dysfunctions. Such an approach may enhance treatment efficacy, and may ultimately help reduce costs in drug development and in the management of patients in clinical practice.

Tu2057 Assessment of Bowel Symptoms, Colonic Transit, and the Relationship to Fecal Bile Acid (BA) Excretion in Health and Irritable Bowel Syndrome (IBS)

Background: Idiopathic bile acid malabsorption (BAM) causes chronic diarrhea and BA deficiency may cause constipation. BA supplementation and an ileal BA transporter inhibitor, elobixibat, accelerate colonic transit (CT). Rectal infusion of BA (e.g. chenodeoxycholate) induces colonic propulsive motility. Up to 50% of patients with IBS-D have accelerated CT; 20% of patients with IBS-C have delayed CT. The relationship between fecal BA excretion, CT, and bowel symptoms in IBS is unclear and may be relevant to selecting optimal therapy. Aim: To assess stool frequency (number) and consistency (form) in relation to CT and fecal BA excretion in healthy participants and patients with IBS-C and IBS-D. Methods: In a prospective study of 92 participants (31 healthy, 30 IBS-C and 31 IBS-D by Rome III criteria), we measured total and individual fecal BA and fecal fat (on 100g fat diet), overall CT by validated scintigraphy (geometric center, GC at 24 and 48h) and stool characteristics by a 14 day bowel pattern diary including Bristol stool form scale. Univariate associations between endpoints were assessed using Spearman correlation (rs). Relationships between stool characteristics, CT and fecal BA excretion were assessed using response surface multiple regression models (which included BMI as a covariate and linear, quadratic and cross product terms for the CT and BA measurements). Results: 1. There were significant univariate associations (table showing rs) between stool number and stool form and total fecal BA (including % LCA, % CDCA, and % CA), fecal fat, and GC24 and 48. 2. The response surface model for stool number (figure left panel) with total fecal BA and CT (GC24 ) explained 29% of the variation (r=0.54, p,0.001); similarly, the model for stool form (figure middle panel) with fecal BA and CT (GC24) explained 20% of the variation (r=0.45, p=0.021). Using total secretory BA (CA+DCA+CDCA), the response surface model for stool form (figure right panel) explained 23% of the variation (r=0.49, p=0.006). In these models, the relative contribution of CT was consistently greater than that for BA, with the coefficients corresponding to CT being statistically significant (p,0.05), while those for BA were borderline (e.g. p=0.073 for the coefficient for secretory BA and stool form, and p=0.227 for stool number). Conclusion: Relative to fecal BA, colonic transit is the greater determinant of stool number and stool form; increased total and secretory fecal BA enhance the effects of colon transit on stool characteristics, but are not independently significant factors. Funding:NIHDK92179

Tu2058 The Combined Nutrient and Lactulose Challenge Test: A New Non-Invasive Test for Visceral Sensitivity in Irritable Bowel Syndrome (IBS)

Background: Idiopathic bile acid malabsorption (BAM) causes chronic diarrhea and BA deficiency may cause constipation. BA supplementation and an ileal BA transporter inhibitor, elobixibat, accelerate colonic transit (CT). Rectal infusion of BA (e.g. chenodeoxycholate) induces colonic propulsive motility. Up to 50% of patients with IBS-D have accelerated CT; 20% of patients with IBS-C have delayed CT. The relationship between fecal BA excretion, CT, and bowel symptoms in IBS is unclear and may be relevant to selecting optimal therapy. Aim: To assess stool frequency (number) and consistency (form) in relation to CT and fecal BA excretion in healthy participants and patients with IBS-C and IBS-D. Methods: In a prospective study of 92 participants (31 healthy, 30 IBS-C and 31 IBS-D by Rome III criteria), we measured total and individual fecal BA and fecal fat (on 100g fat diet), overall CT by validated scintigraphy (geometric center, GC at 24 and 48h) and stool characteristics by a 14 day bowel pattern diary including Bristol stool form scale. Univariate associations between endpoints were assessed using Spearman correlation (rs). Relationships between stool characteristics, CT and fecal BA excretion were assessed using response surface multiple regression models (which included BMI as a covariate and linear, quadratic and cross product terms for the CT and BA measurements). Results: 1. There were significant univariate associations (table showing rs) between stool number and stool form and total fecal BA (including % LCA, % CDCA, and % CA), fecal fat, and GC24 and 48. 2. The response surface model for stool number (figure left panel) with total fecal BA and CT (GC24 ) explained 29% of the variation (r=0.54, p,0.001); similarly, the model for stool form (figure middle panel) with fecal BA and CT (GC24) explained 20% of the variation (r=0.45, p=0.021). Using total secretory BA (CA+DCA+CDCA), the response surface model for stool form (figure right panel) explained 23% of the variation (r=0.49, p=0.006). In these models, the relative contribution of CT was consistently greater than that for BA, with the coefficients corresponding to CT being statistically significant (p,0.05), while those for BA were borderline (e.g. p=0.073 for the coefficient for secretory BA and stool form, and p=0.227 for stool number). Conclusion: Relative to fecal BA, colonic transit is the greater determinant of stool number and stool form; increased total and secretory fecal BA enhance the effects of colon transit on stool characteristics, but are not independently significant factors. Funding:NIHDK92179

Motility disorders of the colon and rectum

Symptoms associated with disorders of the motility of colon and rectum are common problems in clinical practice. Advances in this field continue to expand our understanding of these disorders and provide new and different treatments with promising results. This article reviews new advances in the past year on the measurement and diagnosis of colonic transit. Recently published data question the importance of dietary fiber in the prevention of colonic diverticulosis and diverticulitis, and support the efficacy of a number of different therapies aimed at improving colonic motility and visceral sensation in constipation and reversing the effects of opioid induced constipation with peripherally acting opioid antagonists. The articles referenced in this review help inform the reader on new developments in the diagnosis and management of patients with colonic and rectal motility disorders.

Colonic dysmotility in constipation

Constipation is a common and distressing condition with major morbidity, health care burden, and impact on quality of life. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in the most severe cases of chronic constipation and physiological testing plays a role in identifying the colonic dysmotility and the subsequent patient management. Measurement of colonic motor patterns and transit has enhanced our knowledge of normal and abnormal colonic motor physiology. The scope of this review encompasses the latest findings that improve our understanding of the motility disorders associated with colonic dysfunction in both the paediatric and adult population suffering from constipation.

Measurement of gastrointestinal and colonic transit in mice

Measurement of gastrointestinal and colonic transit in mice

Scintigraphic Biomarkers for Colonic Dysmotility

Scintigraphic colonic transit measurement has emerged as a unique disease-related biomarker pertinent to drug development and personalized therapy. This surrogate offers reproducible and accurate performance across a spectrum of common colonic motility disorders, linking colonic transit measurements to biological processes and clinical end points. The pathobiologic validity, prognostic utility, performance characteristics, evidence-based linkage of therapeutic intervention with outcome, applicability across distinct pharmacodynamic profiles, and potential for individualizing patient management are all attributes of this gastrointestinal imaging paradigm. The cumulative evidence suggests that the integration of colonic transit measurement as a biomarker would accelerate the development and regulatory approval of therapeutic agents for the treatment of colonic dysmotility. Clinical Pharmacology & Therapeutics (2010) 87 6, 748–753. doi: 10.1038/clpt.2010.23

Performance characteristics of scintigraphic colon transit measurement in health and irritable bowel syndrome and relationship to bowel functions

The inter- and intra-subject variations of scintigraphy, which are used to identify colonic transit disturbances in irritable bowel syndrome (IBS), are unclear. The relationship between colonic transit and bowel functions is incompletely understood. To assess inter- and intra-subject variations of scintigraphic colonic transit measurements in 86 IBS patients and 17 healthy subjects and to quantify the relationship between colonic transit and bowel symptoms in 147 IBS patients and 46 healthy subjects. Data from participants with multiple colonic transit measurements were analysed. Primary end points were colonic filling at 6 h (CF6h) and geometric center (GC) at 24 and 48 h for colonic transit. Bowel functions were assessed by daily stool diaries. Inter- and intra-subject variations were greater for small intestinal than colonic transit. Overall, inter- and intra-subject variations were relatively narrow for colonic transit (both GC24h and GC48h, with lower COV at 48 h); there was little intra-subject variation in health and IBS-constipation over a period of <or=3 weeks and over 2.0 years (median, range 0.1, 11.0 years). Significant intra-individual differences in GC24h were observed only in IBS-D patients. Colonic transit was significantly associated with stool form (accounting for 19-27% of the variance), frequency (19%), and ease of stool passage (12%). Despite inter-subject variation in scintigraphic colonic transit results, the intra-subject measurements are reproducible over time in healthy volunteers and patients with IBS; significant changes in colonic transit at 24 h were observed only in IBS-D. Colonic transit is associated with stool form, frequency and ease of passage.

Inhibition of p38 Mitogen-Activated Protein Kinase Pathway as Prophylaxis of Postoperative Ileus in Mice

Postoperative ileus, an iatrogenic complication of abdominal surgery, is mediated by severe inflammation of the tunica muscularis. Macrophages that reside in the muscularis have important roles in initiating the inflammation. We investigated whether activation of the p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase is involved in the genesis of postoperative ileus, and whether p38-MAPK inhibition by the macrophage-specific inhibitor semapimod prevents intestinal dysmotility. Postoperative ileus was induced by intestinal manipulation of the small bowel in mice. Protein kinase phosphorylation was assessed by immunoblotting of muscularis externa preparations. Proinflammatory gene expression was quantified by real-time polymerase chain reaction. Myeloperoxidase histochemistry for neutrophils was performed in jejunal segments. Nitric oxide production was measured by Griess reaction in smooth-muscle organ culture supernatants. Jejunal contractility was assessed within an organ bath setup. Intestinal motility was analyzed by gastrointestinal and colonic transit measurements. High levels of p38-MAPK and stress-activated protein kinase phosphorylation were observed immediately after intestinal manipulation. Semapimod treatment led to a significant decrease of p38-MAPK phosphorylation in macrophages; proinflammatory gene expression of macrophage inflammatory protein-1alpha, interleukin-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule-1; and neutrophil infiltration. Furthermore, semapimod completely abrogated nitric oxide production within the tunica muscularis. Subsequently, semapimod prevented the suppression of smooth muscle contractility and small intestinal and colonic motility after intestinal manipulation. A single preoperative semapimod administration prevents intestinal macrophage activation and subsequent gastrointestinal dysmotility induced by abdominal surgery. Semapimod inhibits p38-MAPK and nitric oxide production in macrophages, making it a promising strategy for prophylaxis of postoperative ileus.

Measurement of colonic transit using a delayed-release capsule containing radio-opaque markers

Objective. Colonic transit scintigraphy has several advantages in comparison with radio-opaque marker (ROM) techniques but it is limited to specialized centers. The aim of the study was to validate the ROM technique for measuring colonic transit using delayed-release capsules. Material and methods. Colonic transit is expressed as the sum of the weighted mean marker residence times in the colon (geometric centers). Delayed-release capsules containing radio-opaque markers (DC-ROMs) or scintigraphic methods were compared simultaneously in 10 healthy volunteers. Reproducibility and responsiveness of DC-ROM measurements were evaluated in 10 healthy volunteers at an interval of 2 weeks and after bisacodyl treatment, respectively. Results. The transit profiles between the scintigraphic and DC-ROM methods were highly correlated (r=0.994, p<0.01). The reproducibility and responsiveness of DC-ROM measurements were good. Colonic transit measured by DC-ROM correlated with the stool form scale (r=0.66, p<0.01). Conclusion. The DC-ROM test is simple, highly reproducible, responsive, and appropriate for clinical trials and clinical practice.

Pilot study of the efficacy of renzapride on gastrointestinal motility and symptoms in patients with constipation‐predominant irritable bowel syndrome

To investigate the efficacy and safety of renzapride, a potent 5-hydroxytryptamine type-4 receptor full agonist and 5-hydroxytryptamine type-3 receptor antagonist in patients with constipation-predominant irritable bowel syndrome. In this dose-escalating pilot study, 17 patients with constipation-predominant irritable bowel syndrome received placebo, renzapride 2 mg o.d. and renzapride 2 mg b.d. sequentially for 28 days. Response was determined by radio-opaque marker measurement of overall gastrointestinal and segmental colonic transit and patients' assessment of their irritable bowel syndrome symptoms. Renzapride reduced mean overall gastrointestinal transit time (placebo, 2.9 +/- 1.6 days; renzapride 2 mg o.d., 2.6 +/- 1.4 days; renzapride 2 mg b.d., 1.9 +/- 1.6 days) (P = 0.024) and accelerated segmental colonic transit, with statistically significant differences for renzapride 2 mg b.d. over placebo in caecum/ascending colon (P = 0.019) and descending colon (P = 0.022). Renzapride also reduced abdominal pain, increased the number of pain-free days and improved stool consistency. The frequency of reported adverse events was similar on renzapride and placebo. Renzapride is well-tolerated, stimulates gastrointestinal transit and improves symptoms in patients with constipation-predominant irritable bowel syndrome, particularly at the 2 mg b.d. dose, where improvements in gastrointestinal symptoms were evident over placebo. This study has established proof of concept and supports further investigation of renzapride in patients with constipation-predominant irritable bowel syndrome.

A randomized controlled trial of a probiotic combination VSL# 3 and placebo in irritable bowel syndrome with bloating

To evaluate the effects of a combination probiotic on symptoms and colonic transit in patients with irritable bowel syndrome (IBS) and significant bloating. Forty-eight patients with Rome II IBS were randomized in a parallel group, double-blind design to placebo or VSL# 3 twice daily (31 patients received 4 weeks and 17 patients 8 weeks of treatment). Pre- and post-treatment colonic transit measurements were performed using scintigraphy with (111)In charcoal. Symptoms were summarized as an average daily score for the entire period of treatment and separately for the first 4 weeks of treatment. Weekly satisfactory relief of abdominal bloating was assessed. Treatment with VSL# 3 was associated with reduced flatulence over the entire treatment period (placebo 39.5 +/- 2.6 vs VSL# 3 29.7 +/- 2.6, P = 0.011); similarly, during the first 4 weeks of treatment, flatulence scores were reduced (placebo 40.1 +/- 2.5 vs VSL# 3 30.8 +/- 2.5, P = 0.014). Proportions of responders for satisfactory relief of bloating, stool-related symptoms, abdominal pain and bloating scores were not different. Colonic transit was retarded with VSL# 3 relative to placebo (colon geometric center 2.27 +/- 0.20 vs 2.83 +/- 0.19, P = 0.05 respectively). VSL# 3 reduces flatulence scores and retards colonic transit without altering bowel function in patients with IBS and bloating.

Reference values for the geometric centre analysis of colonic transit measurements with 111indium-labelled diethylenetriamine penta-acetic acid.

The geometric centre analysis is often used for evaluating colonic transit data obtained by scintigraphy after oral intake of 111indium-labelled diethylenetriamine penta-acetic acid (111In-DTPA). The purpose of this study was to establish reference values for the geometric centre analysis in adult humans. Forty-eight healthy volunteers (24 women, 24 men) who were equally distributed among three age groups (young, middle-aged, elderly) were studied. In all subjects the geometric centre of radioactivity in the colon was calculated from abdominal gamma camera images acquired 24, 48, 72, and 96 h after oral administration of 111In-DTPA. Overall, the men had a higher geometric centre value than women after both 24 and 48 h indicating a faster progress of colonic contents in men at these time points. At each time point the geometric centre value was higher in both the young and middle-aged subjects than in the elderly subjects, whereas we did not find any difference between young and middle-aged subjects. Furthermore, the smokers had a higher geometric centre value than non-smokers at each time point. The geometric centre value was not influenced by body mass index at any time point.

Gender Differences in Gut Transit Shown with a Newly Developed Radiological Procedure

Background: Gut transit measurements are essential for understanding the pathophysiology of many gastrointestinal disorders. The ideal bowel transit test should be easy to perform, widely accessible, reproducible, non-invasive and inexpensive and the risks should be minimal. These requirements prompted us to develop a procedure for simultaneous measurement of gastric emptying, small-bowel transit and colonic transit at one visit. We assessed the influence of gender, body mass index, age, menopause and smoking on gastrointestinal transit in healthy subjects. Methods: Eighty-three healthy subjects (43 women) were included. Colonic transit was based on 10 radiopaque rings given daily for 6 days with fluoroscopy on day 7. Then, the subjects had a test meal containing 20 radiopaque markers. Using fluoroscopy, gastric emptying and small-bowel transit of the markers were followed until they reached the colon. Results: Gastric emptying, small-bowel transit and colonic transit were significantly slower in female healthy subjects compared to males (2.9 (1.6-4.9) h, median and percentile 10-90, versus 2.4 (0.7-3.7) h, P = 0.005; 4.4 (2.1-11.1) h versus 3.2 (1.5-6.0) h, P = 0.00l; 1.5 (1.0-3.7) days versus 1.3 (0.8-1.9) days P = 0.002), respectively. Small-bowel transit was significantly faster in women with overweight and in postmenopausal women compared to lean and premenopausal women, respectively. Conclusion: This procedure meets most of the requirements of the ideal bowel transit test and is easily performed at one visit. Small-bowel transit as well as gastric emptying and colonic transit were significantly slower for women.

Laparoscopically assisted subtotal colectomy for slow-transit constipation.

When medical therapy fails, slow-transit constipation (STC), a condition seen almost exclusively in women, can be treated surgically. The aim of this study was to describe our results with laparoscopically assisted subtotal colectomy (LASC) for STC. Over a 22-month period, four female patients underwent LASC with ileorectal anastomosis for STC at our hospital. The preoperative workup included clinical assessment, evacuation proctography, rectoanal manometry, and colonic transit measurement. Mobilization of the whole colon and ligation and division of colonic mesenteric vessels with preservation of the omentum were achieved laparoscopically. Through a small Pfannenstiel incision, the colon was removed from the abdomen, leaving a 15-cm rectal stump in situ. The rectal stump was fully mobilized posteriorly, a side-to-end ileorectal anastomosis was fashioned, and the rectal stump was fixed onto the presacral fascia with sutures. The operating time ranged from 150 to 260 min and blood loss was minimal. There were no conversions to open surgery. The postoperative course was uneventful in all patients but one, a 47-year old woman who had transient severe abdominal distension, pain, and frequent small-volume bowel movements. All patients were discharged by the 4th to 10th postoperative day. At 9-month follow-up, all of our patients had normal anorectal function with two to four solid bowel movements per day. Although it is a technically demanding procedure, laparoscopically assisted colectomy for slow-transit constipation, can be achieved safely.

Activated charcoal as a potential radioactive marker for gastrointestinal studies.

The scintigraphic measurement of colonic transit is currently performed using 111In ion exchange resin pellets delivered to the colon in a capsule coated with a pH sensitive polymer, methacrylate, which dissolves in the distal ileum. However, in the USA, this requires an investigational drug permit. Our aim was to evaluate the in vitro binding characteristics of activated charcoal in milieus that mimicked gastric and small intestinal content. The in vitro incubation of activated charcoal was performed with Na99Tc(m)O4, 99Tc(m)-DTPA, 111InCl3, 111In-DTPA, 201TlCl and 67Ga-citrate in the pH range 2-4 and pH 7.2 at 37 degrees C. We estimated the association of radiopharmaceuticals with the activated charcoal over a 3 h in vitro incubation. With the exception of 67Ga-citrate, the association of activated charcoal with the other radiopharmaceuticals was approximately 100% throughout the 3 h incubation. In conclusion, activated charcoal appears to adsorb avidly with common radioisotopes, and appears promising as an alternative to resin ion exchange pellets used for the measurement of gastrointestinal transit by scintigraphy.

Gastrointestinal transit in patients with idiopathic megarectum

In patients with idiopathic megarectum, it is unknown whether abnormality is limited to the dilated large bowel or whether the upper gut is abnormal, as in the various forms of chronic intestinal pseudo-obstruction. This has important implications for treatment, especially surgery. Ten patients (4 females; median age, 18 (range, 17-26) years) with idiopathic megarectum had contrast studies of the upper and lower gut, radioisotope (technetium-99m liquid and indium-111 solid phase) measurement of gastric, small-bowel, and colonic regional transit, and radiopaque marker colonic studies. All patients had a dilated large bowel. No patient had radiographic evidence of upper gut dilation. Four patients had normal and six patients had abnormally slow gastric emptying. Both the radioisotope scans and radiopaque marker studies showed abnormal colonic transit. Regions of delay corresponded with the region of dilated bowel. Symptoms of abdominal distention and bloating did not correspond to abnormalities of gastric emptying but rather with effectiveness of rectal evacuation. Patients with idiopathic megarectum have abnormal colonic transit, delay occurring predominantly in the dilated gut. Marker studies are less sensitive than isotope studies but provide adequate information for clinical purposes. Although motility abnormalities of the upper gut are common, symptoms correlate with large-bowel abnormalities.