Demonstration of differences in colonic volumes, transit, chyme consistency, and response to psyllium between healthy and constipated subjects using magnetic resonance imaging.

BACKGROUND: In functional gastrointestinal disorders a lack of objective biomarkers limits evaluation of underlying mechanisms. We aimed to demonstrate the utility of magnetic resonance imaging for this task using psyllium, an effective constipation treatment, in patients and controls. METHODS: Two crossover studies: (i) adults without constipation (controls, n = 9) took three treatments in randomized order for 6 days - maltodextrin (placebo), psyllium 3.5 g t.d.s and 7 g t.d.s., (ii) adults with chronic constipation (patients, n = 20) took placebo and psyllium 7 g t.d.s. for 6 days. MRI was performed fasting and postprandially on day 6. Measurements included small bowel and ascending colon water content, colonic volume, transit time, and MR relaxometry (T1, T2) to assess colonic chyme. Stool water percentage was measured. RESULTS: 7 g psyllium t.d.s. increased fasting colonic volumes in controls from median 372 mL (IQR 284-601) to 578 mL (IQR 510-882), and in patients from median 831 mL (IQR 745-934) to 1104 mL (847-1316), P < .05. Mean postprandial small bowel water was higher in controls and patients after 7 g psyllium t.d.s. vs placebo. Whole gut transit was slower in patients than controls (P < .05). T1 of the descending colon chyme (fasting) was lower in patients (213 ms, 176-420) than controls (440 ms, 352-884, P < .05) on placebo, but increased by 7 g psyllium t.d.s. (590 ms, 446-1338), P < .001. Descending colon T1 correlated with baseline stool water content and stool frequency on treatment. CONCLUSIONS AND INFERENCES: MRI measurements can objectively demonstrate the mode of action of therapy targeting intestinal fluid content in constipation.

Diagnosis of colonic volvulus: findings on multidetector CT with three-dimensional reconstructions.

Large bowel volvulus is a rare condition that can occur in patients who present with acute abdominal pain. Radiologists should be able to recognise its appearance on multidetector CT (MDCT) images so that the correct diagnosis can be made and catastrophic consequences can be avoided. In this article, we discuss and illustrate the MDCT and three-dimensional appearance of the various forms of large bowel volvulus. As MDCT allows the precise diagnosis of topography, mechanism and severity, this technique can provide an accurate assessment of large bowel volvulus.

Lack of utility of abdominal x-rays in the evaluation of children with constipation: comparison of different scoring methods.

BACKGROUND AND AIM: Abdominal x-rays are used diagnostically in the evaluation of children with constipation. However, their clinical utility has not been established. The aim of the study was to assess the accuracy of different methods in identifying children with functional constipation (FC) or nonretentive fecal incontinence (NRFI). PATIENTS AND METHODS: Retrospective review of abdominal x-rays in which colonic transit (CT), Barr, Leech, and fecal loading (FL) scores were blindly measured by blinded pediatric gastroenterologists and a radiologist. Children were classified a priori as FC or NRFI. RESULTS: One hundred sixty patients (125 FC, 35 NRFI) were studied. There were significant differences (P < 0.05) when comparing those with FC and those with NRFI: CT: 51 +/- 18 vs 40 +/- 21 hours; Barr: 14 +/- 5 vs 11 +/- 4; Leech: 10 +/- 2 vs 8 +/- 2; FL: 2 +/- 0.5 vs 1.7 +/- 0.4. More than 20% of FC had normal Barr and Leech scores, whereas >50% of NRFI had abnormal scores. CT discriminated better between FC and NRFI. There was a significant correlation (P < 0.05) between CT and Barr (0.45), Leech (0.41) and FL scores (0.36), and between Barr and Leech scores (r = 0.94). There was good intraobserver correlation between Barr, Leech, and FL scores but poor interobserver reproducibility. CONCLUSIONS: Although significant differences in overall FC and NRFI scores exist, the discriminative value is low for all scores. There is poor interobserver reproducibility of the Barr, Leech, and FL scores. These findings confirm the limited value of the plain abdominal x-ray in the evaluation of children with constipation.

[X-ray colonometry in the diagnosis of colonic dyskinesias and inflammatory diseases].

Clinical and X-ray studies were made in 316 patients, which revealed intestinal dyskinesia, chronic colitis, and nonspecific ulcerative colitis in 105, 133, and 78 patients, respectively. Irrigoscopy (administration of a contrast enema, examination of the mucosal contour, and double contrasting) was performed in all the patients, by analyzing X-ray planimetric indices. X-ray colonoplanimetry makes it possible to objectify the interpretation of the X-ray pattern in chronic inflammatory diseases of the large bowel and colonic dyskinesia.

Sex differences of brain serotonin synthesis in patients with irritable bowel syndrome using alpha-[11C]methyl-L-tryptophan, positron emission tomography and statistical parametric mapping.

BACKGROUND: Irritable bowel syndrome (IBS) is the most common functional bowel disorder and has a strong predominance in women. Recent data suggest that the brain may play an important role in the pathophysiology of IBS in the brain-gut axis. It is strongly suspected that serotonin (5-HT), a neurotransmitter found in the brain and gut, may be related to the pathophysiology of IBS. It is reported that a 5-HT3 antagonist is effective only in female patients with diarrhea-predominant IBS. OBJECTIVE: In the present study, 5-HT synthesis was measured using positron emission tomography, with alpha-[11C]methyl-L-tryptophan as the tracer, in patients with IBS. The aim of the present study was to compare 5-HT synthesis in the IBS patients with that in the controls, and to compare 5-HT synthesis between male and female IBS patients. METHODS: Six male and six female nonconstipated IBS patients were scanned. Age-matched healthy volunteers were scanned as controls. Eighty minute dynamic scans were performed. Functional 5-HT synthesis images were analyzed using statistical parametric mapping. RESULTS: 5-HT synthesis was greater only in the female IBS patients in the right medial temporal gyrus (multimodal sensory association cortex) compared with the female controls (P<0.001). CONCLUSIONS: The greater brain 5-HT synthesis in the female IBS patients than in the controls may be related to the pathological visceral pain processing of the IBS patients, a larger female predominance of the disorder, and the sex difference of the efficacy of the 5-HT3 antagonist in treatment.

Abnormalities of GI transit in bloated irritable bowel syndrome: effect of bran on transit and symptoms.

OBJECTIVES: Bloating is an important but poorly understood symptom in irritable bowel syndrome (IBS) that is often aggravated by bran. The aim of our study was to determine whether IBS patients with bloating responded to bran differently from healthy controls. METHODS: A total of 12 patients with IBS (according to Rome I criteria), all with moderate to severe bloating, and 12 healthy controls participated in a two way, double blind, randomized, cross-over trial of bran versus placebo (crushed biscuits) 15 g b.i.d. An average daily pain index and bloating score were derived from daily symptom diaries. On day 14, gastric emptying, small bowel transit, percent remaining in ascending colon, and geometric center of a meal marker at 24 h were calculated from scintigraphic images obtained after ingesting a Tc99m-labeled rice pudding meal with 15 g of either placebo or coarse bran. RESULTS: Results are given as median (range). Bran significantly increased the pain index and bloating (p < 0.02) in IBS patients but not controls. The most striking finding was that the small bowel transit time of the meal without bran was markedly faster in IBS patients than in controls, being 203 min (range 109-313) versus 367 min (219-543), p < 0.001. Although in controls bran accelerated small bowel transit time to 262 min (180-380), p = 0.03, and significantly reduced % remaining in the ascending colon from 22% (0-46) to 3% (0-25), p = 0.03, this was not seen in the IBS patients. Bran accelerated whole gut transit as assessed by geometric center at 24 h in both IBS patients and controls. CONCLUSIONS: Bran accelerates small bowel transit and ascending colon clearance without causing symptoms in controls. Small bowel transit is rapid in IBS patients with bloating and, unlike in healthy control subjects, cannot be further accelerated by bran, which nevertheless aggravates symptoms of pain and bloating. We speculate that bran-induced bloating may originate in the colon rather than the small bowel.

The effect of the 5-HT3 receptor antagonist, alosetron, on brain responses to visceral stimulation in irritable bowel syndrome patients.

AIM: To conduct a placebo-controlled functional brain imaging study to assess the effect of the 5-hydroxytryptamine-3 receptor antagonist, alosetron, on irritable bowel syndrome symptoms, regional brain activation by rectosigmoid distension and associated perceptual and emotional responses. METHODS: Fifty-two non-constipated irritable bowel syndrome patients (28 female) were enrolled in a randomized, placebo-controlled trial with alosetron (1-4 mg b.d.). Thirty-seven patients completed both brain scans following randomization. Rectosigmoid stimulation was performed with a computer-controlled barostat. Changes in regional cerebral blood flow were assessed using H215O positron emission tomography. Stimulus ratings and changes in gastrointestinal symptoms were assessed using verbal descriptor scales. RESULTS: Alosetron, but not placebo, treatment was associated with a decrease in symptom ratings, and reductions in emotional stimulus ratings. Compared to baseline, alosetron treatment was associated with reduced regional cerebral blood flow in bilateral frontotemporal and various limbic structures, including the amygdala. Compared to placebo, decreases in activity of the amygdala, ventral striatum, hypothalamus and infragenual cingulate gyrus were significantly greater after alosetron. CONCLUSIONS: In non-constipated irritable bowel syndrome patients, 3 weeks of treatment with a 5-hydroxytryptamine-3 receptor antagonist decreases brain activity in response to unanticipated, anticipated and delivered aversive rectal stimuli in structures of the emotional motor system, and this is associated with a decrease in gastrointestinal symptoms.

Abdominal pain and bowel dysfunction: diagnostic role of intestinal ultrasound.

BACKGROUND: Abdominal pain and irregular bowel habits are common among young people. Irritable bowel syndrome is frequent in the general population and has important economic and social costs. Inflammatory bowel diseases are chronic processes with an acute or indolent onset in young people. Differential clinical diagnosis between irritable bowel syndrome and inflammatory bowel disease can be difficult since symptoms and signs are often non-specific. OBJECTIVE: To evaluate the role of intestinal ultrasound, a non-invasive, simple and cheap diagnostic tool, in the differentiation between organic and functional bowel diseases. METHODS: Abdominal and intestinal ultrasound examinations were performed on 313 consecutive outpatients presenting with abdominal pain and irregular bowel habits lasting more than 3 months. These patients had no symptoms or signs indicative of organic disorders and no previous diagnosis of organic disease. An intestinal wall thickness of more than 7 mm was considered diagnostic for inflammatory bowel disease. Subsequently, we compared the ultrasound results with diagnoses obtained following the traditional criteria (radiological and endoscopic examinations). RESULTS: Intestinal ultrasound for the diagnosis of inflammatory bowel disease showed 74% sensitivity, 98% specificity, a positive predictive value of 92% and a negative predictive value of 92%. CONCLUSIONS: In our experience, intestinal ultrasound seems important as a first diagnostic tool in young patients without clear symptoms or signs of organic diseases, and can be used as an indication that subsequent invasive tests are required.

Quantitative analysis of bowel gas using plain abdominal radiograph in patients with irritable bowel syndrome.

OBJECTIVE: Ideally, the diagnosis of irritable bowel syndrome (IBS) would be achieved using a minimal number of procedures. It is presumed that bowel gas is related to IBS, and it is easily visualized by plain abdominal radiograph. In the present study, to clarify the relationship between IBS and the quantity of bowel gas, the measured bowel gas volume using plain abdominal radiographs was compared with the pathology of IBS. METHODS: Plain abdominal radiographs were digitized and transmitted to a computer (computed radiography) in 30 IBS patients and 30 normal controls. The quantity of bowel gas, determined as the pixel value on images and standardized by physique, was defined as the gas volume score (GVS). Using the mean +/- 2SD of GVS in the control group as the normal score, IBS patients were divided into three groups: high, normal, and low. To examine the sequential reproducibility of a similar quantity of bowel gas, a second plain abdominal radiography was performed about 2 months later, and the GVS were compared. The colonic transit time was determined using radiopaque markers. RESULTS: There was a strong correlation between the quantities of bowel gas measured by two independent gastroenterologists. The mean GVS of IBS patients was significantly higher than that in the control group (p < 0.001). The sequential reproducibility was recognized in all 10 IBS patients. There was no significance between colonic transit time and GVS, nor between symptoms and GVS. CONCLUSIONS: Abdominal gas was analyzed objectively by using GVS, and GVS was considered to represent a useful tool for the diagnosis of IBS.

Tegaserod accelerates orocecal transit in patients with constipation-predominant irritable bowel syndrome.

BACKGROUND & AIMS: This study evaluated the effects of a partial 5-hydroxytryptamine (5-HT)(4) agonist, tegaserod, on gastric small bowel and colonic transit in constipation-predominant irritable bowel syndrome (IBS). METHODS: After a 1 week run-in period, 24 patients with constipation-predominant IBS were randomized to 1 week of tegaserod, 2 mg twice daily, or placebo treatment. Scintigraphic gastric emptying, small bowel transit, and colonic transit were determined before administration of study drug and after 1 week on the medication. Colonic transit was also measured using radiopaque markers and a single radiograph on day 5. RESULTS: Gastric emptying was unaltered by tegaserod. Proximal colonic filling at 6 hours, a measure of orocecal transit, was accelerated by tegaserod (70.4% +/- 1.3% [mean +/- SEM] vs. placebo, 46.4 +/- 1.9; P = 0.015). Proximal colonic emptying half-time and geometric center at 48 hours were also accelerated by tegaserod compared with baseline, but not compared with placebo. Mean colonic transit time was similar in both groups at baseline and after drug administration (tegaserod, 59.5 +/- 2.1 hours; placebo, 62.1 +/- 2.1 hours). CONCLUSIONS: Tegaserod accelerates orocecal transit, tends to accelerate colonic transit, and deserves further study in patients with constipation-predominant IBS.

[Abdominal pain and bowel dysfunction: the diagnostic role of ultrasonography]. / Dolore addominale e alterazione dell'alvo. Ruolo diagnostico dell'ecotomografia.

PURPOSE: To evaluate the role of intestinal ultrasound (US) in differentiating organic from functional bowel disease. MATERIAL AND METHODS: We examined with abdominal and intestinal US 313 consecutive outpatients presenting abdominal pain and bowel dysfunction, lasting more than 3 months, with no symptoms or signs of alarm and with no previous diagnosis of organic disease. Our population consisted of 191 women and 122 men, with average age at diagnosis of 36.5 years; 236 of these patients had irritable bowel syndrome, 61 Crohn's disease, and 16 ulcerative colitis. Intestinal wall thickness exceeding 7 mm was considered diagnostic for inflammatory bowel diseases. We compared US findings with the diagnosis made with the conventional diagnostic workup of radiological and endoscopic examinations. RESULTS: Sensitivity of intestinal US for diagnosis of inflammatory bowel diseases was 74% and specificity 98% (respectively 84% and 98% for the diagnosis of Crohn's disease and 38% and 98% for ulcerative colitis), and positive and negative predictive values were both 92%; efficacy was also 92%. The likelihood ratio was 35 if US was positive for inflammatory bowel diseases and 0.26 if bowel wall thickness was less than 7 mm. Diagnostic efficacy was 95% for Crohn's disease and 94% for ulcerative colitis. DISCUSSION: Intestinal US proved to be a valuable tool in diagnosing Crohn's disease. As the first step examination US can show the disease site and suggest further instrumental tests. CONCLUSIONS: In our experience intestinal US is an important diagnostic examination for the approach to young patients without symptoms or signs suggestive of organic diseases and can help avoid invasive instrumental examinations.

Altered gastric emptying in patients with irritable bowel syndrome.

Irritable bowel syndrome is the most frequent functional disorder of the digestive system. Patients with irritable bowel syndrome have motor disorders not only in the colon, but also in other parts of the digestive tract such as the oesophagus and small intestine; however, it is not known whether the stomach is also involved. We used a radiolabelled mixed solid-liquid meal (technetium-99m for the solid component, indium-111 for the liquid component) to study gastric emptying of solids (GES), liquids (GEL) and indigestible solids (GER) in 50 patients diagnosed as having irritable bowel syndrome (30 with predominant constipation and 20 with predominant diarrhoea). GER was measured by counting the number of indigestible solids remaining in the stomach 4 h after they were swallowed. In patients with irritable bowel syndrome, GES and GEL were slower than in control subjects (P<0.05). GER was normal in all patients except for two women. Thirty-two patients (64%) showed delayed GES, 29 (58%) delayed GEL, and 2 (4%) delayed GER. Among patients with irritable bowel syndrome, GES was slower in those with predominant constipation than in those with predominant diarrhoea (P<0.05); GEL and GER were similar in both groups. Gastroparesis was found in a large proportion of patients with irritable bowel syndrome, suggesting the presence of a more generalised motor disorder of the gut.

Gastrointestinal motility in patients with irritable bowel syndrome studied by using radiopaque markers.

BACKGROUND: Irritable bowel syndrome (IBS) has been identified as a physiologic abnormality, but no test has been established as a diagnostic standard for gastrointestinal dyskinesia in IBS patients. The aim of this study was to investigate gastrointestinal motility in patients with IBS by using radiopaque markers. METHODS: Gastrointestinal motility was studied in IBS patients (n = 72), constipation patients (n = 19), diarrhoea patients (n = 9), and healthy controls (n = 23). Using three types of radiopaque markers, analysis was performed to establish the transit time and a new indicator, the 'scattering index'. RESULTS: Transit times were not characteristic in IBS. The patients with IBS had significantly higher scattering indexes in the colon and total gut than the healthy controls and the patients with constipation and diarrhoea. The transit time and scattering index of the colon were linearly correlated in the healthy controls and the constipation and diarrhoea patients but were not correlated in the IBS patients. Using transit time and scattering index was a reliable means of evaluating gastrointestinal motility in IBS patients, with a sensitivity of 65% and a specificity of 96%. CONCLUSION: Three days' use of the radiopaque marker method was useful for providing an objective means of detecting gastrointestinal dysmotility in IBS patients.

Simple clinical assessment of colonic response to food.

The colonic response to food (CRF) is an integrated function of the colon that has been poorly studied in clinical practice. This study describes a new method to measure it, based on the progress of radio-opaque markers, and shows the results in healthy subjects and in patients with irritable bowel syndrome (IBS). Thirty healthy subjects and 43 patients suffering from IBS were studied. Two studies of colonic transit time (CTT), at rest and after eating a standard test meal, were performed. CRF was quantified by calculating the variation in number of markers in each zone of interest of the large bowel using X-ray films of the abdomen taken before and after eating. The results were as follows: (1) CRF is characterised by caudal propulsion of the colonic contents in the two groups. In controls, there is emptying of the cecum-ascending colon region and filling of the distal large bowel. In IBS patients, only emptying of the left transverse colon and the splenic flexure is found. (2) IBS patients have a delayed CTT because of slowing in the right and left colon, and this is both before and after a meal. The determination of the movements of markers after eating is a simple method that is useful in clinical practice to evaluate CRF.

[Measurement of colon transit time useful in the evaluation of functional constipation]. / Meting van colonpassagetijd nuttig bij de evaluatie van functionele obstipatie.

OBJECTIVE: To determine the colon transit time (CTT) in patients complaining of functional constipation and the correlation between abnormal transit times and the types of constipation and of the symptoms. DESIGN: Retrospective, descriptive. SETTING: Department of Surgery, University Hospital, Nijmegen, the Netherlands. METHOD: The signs and symptoms of 112 patients with infrequent or difficult defaecation, 93 (83%) of them women, with a median age of 42 years (range: 16-72), were recorded by means of a questionnaire. After ingestion of radiopaque markers per day for 10 days, an abdominal survey X-ray was made on day 11. The numbers of markers in the X-ray and per segment (right and left hemicolon and rectosigmoid) were counted; the CTT in hours was calculated by multiplying this number by 2.4. Slowness was defined as more than 45 h for the total CTT and as more than 15 h for the segmental CTT. RESULTS: The total CTT was normal in 33 patients (29%) and prolonged in 79 (71%). The CTT was prolonged only in the rectosigmoid in 14 patients with a normal CTT (42%) and in 50 patients with a prolonged total CTT (63%). Of the patients with a normal total CTT, 13 (39%) had a normal segmental CTT. No statistically significant correlation could be demonstrated between the presence of any symptom and a prolonged CTT. CONCLUSION: Functional constipation may be associated with a normal CTT. Disorders of colonic motility and of rectal evacuation could be distinguished by measuring the total and the segmental colonic transit times.

Gastroparesis and small bowel dysmotility in irritable bowel syndrome.

Alterations in both gastric emptying (GE) and small bowel motility have been reported in irritable bowel syndrome (IBS); the relationship, however, between these different measures of upper gut motor function in IBS has not been assessed. The aims of this study were therefore: (1) to compare the prevalence and characteristics of altered small bowel motility in IBS patients with and without delayed GE; and (2) to assess the interrelationships between fasting and postprandial small bowel motility in IBS, accounting for delayed GE. Forty-four IBS patients and 25 healthy controls underwent 24 hr ambulant recording of interdigestive and digestive small bowel motility. On a separate occasion the IBS patients had GE of both solids and liquids measured by a dual-isotope scintigraphic technique. Thirty-nine percent of IBS patients had delayed GE. Patients with normal GE had no interdigestive small bowel abnormalities. However, in patients with delayed GE fasting phase II burst frequency was higher than in controls [median 0.21/hr (IQR 0.15-0.34) vs 0.06/hr (0-0,16), P = 0.004]. Postprandially, abnormal phase III-like activity was higher in diarrhea-predominant IBS patients (0-0.08/hr vs 0/hr, P = 0.01), than in patients with normal GE or controls. Furthermore, IBS patients with delayed GE did not have the normal correlation between fasting and postprandial motor parameters (percentage occurrence of clustered contractions, postprandial pattern duration vs preceding MMC cycle length). In conclusion, small bowel motor dysfunction occurs more frequently in IBS patients with concomitant gastroparesis than in patients with normal GE. These findings provide further evidence that a neuropathic process may contribute to the pathogenesis of IBS in a subgroup of IBS patients.

Defaecography in patients with irritable bowel syndrome and healthy volunteers.

BACKGROUND: In patients with IBS, many symptoms have their origin in the recto-anal segment, with motility changes in the rectum and in the internal anal sphincter, and alterations in rectal sensitivity. However, up to now, it is not known if these clinical and physiological changes are equated with morphological changes in the recto-anal segment. METHODS: Sixteen consecutive patients with IBS (mean age 22, range 18-33 years; 13 females) and 10 healthy volunteers (mean age 34.5, range 19-50 yr.; 6 males) were evaluated prospectively with defaecography. RESULTS: 1) Anorectal angle: No significant differences were observed in the anorectal angle during rest (91.6 +/- 3.5 degrees vs 92.6 +/- 2.5 degrees) and during defaecation (92 +/- 5.5 degrees vs 98.7 +/- 2.6 degrees) between patients with IBS and healthy volunteers. However, patients with IBS were unable to widen the angle during defaecation, remaining the same at rest (91.6 +/- 3.5 degrees) as during defaecation (92 +/- 5.5 degrees). IBS patients with constipation (n = 2) compared to those with normal frequency defaecation (n = 13) showed no significant differences at rest (95 +/- 6 vs 89.8 +/- 4.1 degrees) and during defaecation (100 +/- vs 88.9 +/- 6.4 degrees). Healthy volunteers widened the angle by more than 5 degrees during defaecation. 2) Perineometry: although not significant, patients with IBS had less perineal descent during the simulated defaecation (1.98 +/- 0.37 cm) than healthy subjects (2.1 +/- 0.3 cm). Nevertheless, during squeeze there was significantly less mobility or perineal descent in patients with IBS than in control subjects (0.21 +/- 0.17 vs 0.95 +/- 0.21 cm; P = 0.01). CONCLUSIONS: The findings of this study suggest that patients with IBS as a whole, whether constipation predominant or not, showed changes in pelvic-floor mobility.