Measurement of gastric emptying time by real-time ultrasonography

This paper describes an ultrasound method of assessing gastric emptying time based on measurements of the gastric antrum, which is visible in almost all subjects before and after meals. A total of 54 subjects were examined including 18 normal subjects and 36 subjects with idiopathic functional dyspepsia. The emptying time was determined in all subjects by measuring the changes in the cross-sectional area of the gastric antrum. In a subgroup of 34 subjects the volume of the whole antropyloric region was also considered. Measurements were taken by the same observer after fasting and at regular 30-min intervals after a standard 800-cal meal. Final emptying time (calculated in relation to the start of the meal) was considered to be the time at which the antral area or volume returned to basal value. Final emptying time (mean +/- SD) was 248 +/- 39 min in normal subjects and 359 +/- 64 min in patients with functional dyspepsia (p less than 0.001). A significantly higher degree of dilatation of the gastric antrum was found in dyspeptic patients than in control subjects. Barium x-ray of the stomach in 19 subjects always confirmed the ultrasound finding on the presence or absence of contents within the stomach. We conclude that this kind of ultrasound study of the antropyloric region allows accurate determination of total gastric emptying time.

Gastric emptying of varying meal weight and composition in man. Evaluation by dual liquid- and solid-phase isotopic method

Ten subjects were given self-selected filling meals (mean weight = 1692 g) and meals of 900 and 300 g. The three meals varied in composition and total kcal. Solid and liquid phase gastric emptying was evaluated using 99mTc-sulfur colloid-labeled chicken liver and [111In]DTPA, and emptying was quantitated using the geometric mean of the anterior and posterior counts. Emptying of the solid-phase marker was linear; mean half-emptying times were 277 min, 146 min, and 77 min for the filling, 900-g, and 300-g meals, respectively. Emptying of the liquid-phase marker was curvilinear, mean half-emptying times were 178 min, 81 min, and 40 min, for the filling, 900-g, and 300-g meals, respectively. Thus, meals of larger weight and kcal content were associated with longer emptying times for both solids and liquids.

Relation between postprandial satiation and antral area in normal subjects

The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

Scintigraphic measurement of gastric emptying and ultrasonographic assessment of antral area: relation to appetite

BACKGROUND

Ultrasound measurement of gastric emptying has potential advantages over scintigraphy, but there is little information about its accuracy.

AIMS

The relation between ultrasonographic measurements of antral area and (a) scintigraphic measurements of gastric emptying and intragastric distribution of liquids (b) postprandial satiation, were evaluated.

SUBJECTS

Seven normal volunteers were studied.

METHOD

Each subject drank 75 g dextrose dissolved in 350 ml of water (300 kcal) or beef soup (20 kcal), both labelled with technetium-99m sulphur colloid on separate days and had measurement of gastric emptying by scintigraphy and ultrasound.

RESULTS

Scintigraphic and ultrasound 50% emptying times (T50s) were comparable and longer (p < 0.001) for dextrose than soup mean (SEM) (dextrose 107 (16) min v 108 (18) min, soup 24 (4) min v 23 (5) min). There were close correlations between scintigraphic and ultrasound T50s (dextrose r = 0.94, p < 0.005, soup r = 0.97, p < 0.001) and between the time at which the distal stomach content decreased from its maximum value by 50% (measured scintigraphically) and the ultrasound T50 (dextrose r = 0.95, p < 0.005, soup r = 0.99, p < 0.0001). In contrast, there was no significant relation between the distal stomach content when expressed as a percentage of the maximum content in the total stomach and the ultrasound T50. After dextrose, fullness was related (r = 0.92, p < 0.01) to the postprandial increase in antral area measured by ultrasound.

CONCLUSIONS

Ultrasound measurements of gastric emptying are: (a) of comparable sensitivity to scintigraphy in quantifying emptying of both low and high nutrient liquids (b) correlate with postprandial satiation, suggesting that the latter may be mediated by antral distension.

Physical state of meal affects gastric emptying, cholecystokinin release and satiety

To verify the influence of food consistency on satiety mechanisms we evaluated the effects of the same meal in solid-liquid (SM) and homogenized (HM) form on satiety sensation, gastric emptying rate and plasma cholecystokinin (CCK) concentration. Eight healthy men, aged 21-28 (mean 24.5) years were given two meals (cooked vegetables 250 g, cheese 35 g, croutons 50 g and olive oil 25 g, total energy 2573 kJ, with water 300 ml) differing only in physical state: SM and HM. The subjects consumed the meals in randomized order on non-consecutive days. The sensations of fullness, satiety and desire to eat were evaluated by means of a questionnaire, gastric emptying was assessed by ultrasonographic measurement of antral area, and plasma CCK concentration was measured by radioimmunoassay. The vegetable-rich meal was significantly more satiating (P < 0.05) when in the HM form than when eaten in a SM state. Furthermore, the overall gastric emptying time was significantly slowed (255 (SEM 11) min after HM v. 214 (SEM 12) min after SM; P < 0.05) and CCK peak occurred later (94 (SEM 12) min after HM v. 62 (SEM 11) min after SM; NS) when the food was consumed in the HM form. Independently of the type of meal, antral area was significantly related to fullness sensations (r2 0.46, P = 0.004). These results demonstrate that meal consistency is an important physical food characteristic which influences both gastric emptying rate and satiety sensation. Moreover, the relationship observed between antral area and fullness sensation confirms that antral distension plays a part in the regulation of eating behaviour.

Bedside ultrasound assessment of gastric content: an observational study

PURPOSE

There is a growing interest in the use of bedside ultrasonography to assess gastric content and volume. It has been suggested that the gastric antrum in particular can be assessed reliably by sonography. The aim of this observational study was to provide a qualitative description of the sonographic characteristics of the gastric antrum when the stomach is empty and following the ingestion of clear fluid, milk, and solid content.

CLINICAL FEATURES

Six healthy volunteers were examined on four different occasions (24 scanning sessions): following a period of eight hours of fast and following ingestion of 200 mL of apple juice, 200 mL of 2% milk, and a standard solid meal (sandwich and apple juice). Examinations were performed following a standardized scanning protocol by two clinical anesthesiologists with previous experience in gastric sonography. For each type of gastric content, the sonographic characteristics of the antrum and its content are described and illustrated with figures.

CONCLUSIONS

Bedside sonography can determine the nature of gastric content (nil, clear fluid, thick fluid/solid). This qualitative information by itself may be useful to assess risk of aspiration, particularly in situations when prandial status is unknown or uncertain.

Wide gastric antrum in patients with non-ulcer dyspepsia. Effect of cisapride

Fasting antral area was examined by ultrasonography in 40 healthy subjects and in 106 patients with non-ulcer dyspepsia (NUD) and erosive prepyloric changes (EPC) before and after treatment with cisapride or placebo. The patients were examined twice, first after a run-in period of 14 days of placebo and then after 14 days of cisapride, 10 mg three times daily, or placebo. The relaxed width of the antral area was measured in two sections: a vertical section in which the antrum, the superior mesenteric vein, and the aorta were visualized simultaneously, and a horizontal section that included the pylorus and the middle of the antrum up to 5 cm proximal to the pylorus. The mean antral area was wider (p less than 0.001), both in vertical and horizontal sections, in patients with NUD and EPC than in controls. The antral area in NUD patients was wider (p less than 0.05) in smokers than in non-smokers. The area tended to decrease during treatment with cisapride (p = 0.08). Bloating was the only symptom significantly associated with a wide antral area (p = 0.01). The results suggest a relationship between a wide fasting antral area and NUD with EPC.

Measurement of gastric emptying by standardized real-time ultrasonography in healthy subjects and diabetic patients

The aim of this study was to simplify and standardize a reproducible, well-tolerated and clinically applicable method for the assessment of gastric emptying rate by real-time ultrasonography. A total of 33 subjects were examined, including 19 healthy subjects and 14 patients with insulin-dependent diabetes mellitus and clinically suspected delayed gastric emptying. Measurements of the gastric antrum were taken in the supine position and in relation to internal landmarks to obtain a standardized cross-sectional image producing the area of a selected slice of the antrum. Diabetic patients were examined on the condition that the fasting blood glucose level was 3.5 to 9.0 mmol/l. Gastric emptying rate was estimated and expressed as the percentage reduction in antral cross-sectional area from 15 to 90 min after the ingestion of a standardized semisolid breakfast meal (300 g rice pudding, 330 kcal). Interobserver and intraobserver measurement errors were assessed, as was the significance of age and sex on gastric emptying. In comparison to healthy subjects, diabetic patients showed significantly wider median values of the 90 min postprandial antral area, but only a mild tendency toward greater dilation of the gastric antrum prior to and 15 min after meal ingestion. The median value of gastric emptying rate in these diabetic patients was estimated at 29%, which was less than half of that in the healthy subjects (63%). Statistically the difference was highly significant. Interpersonal variability of gastric emptying rate and antral areas was large for both groups. Measurements of gastric emptying rate gave highly reproducible results on separate days and from different observers (interobserver systematic measurement error 0.3% and random measurement error 10.9%; intraobserver systematic measurement error 3.6% and random measurement error 9.5%). No difference in gastric emptying rate was found related to age or sex. We conclude that the use of standardized real-time ultrasonography to determine gastric antral cross-sectional area in a single section of the stomach is a valid method for estimating gastric emptying rate.

Real time ultrasonography of the gastric antrum

This study aimed to evaluate whether serial ultrasound measurements of antral volumes are reproducible and, if so, whether they are representative of the entire gastric contents and reliably measure gastric emptying. The antral volume was measured in man after oral and intragastric administration of known amounts of 5% glucose solutions, and on two separate occasions in the same subjects, after the ingestion of a standardised solid-liquid meal (1050 kcal). Antral volume measurements were performed in both supine and upright positions; inter- and intraobserver measurement errors were also assessed. After ingestion or intragastric administration of equal amounts of liquid, antral volumes determined by ultrasound showed a wide intersubject variability. In each individual subject, however, a linear trend was found between the antral volume and amount of ingested or administered liquid. Intrasubject variability of antral volume measurements was at its minimum in fasting conditions and 300 minutes after ingestion of the solid-liquid meal. Intra- and interobserver variations and whether the patient was erect or supine did not affect measurements of antral volumes. These results support the use of real time ultrasound in determining the gastric emptying time. Results at fasting and 300 minutes after a solid-liquid meal are stable end points of measurement.

Non-invasive measurement of gastric accommodation in humans

Gastric accommodation describes the reduction in gastric tone and increase in compliance that follows ingestion of a meal and involves at least two responses: "receptive relaxation" which allows the stomach to accept a volume load without a significant rise in gastric pressure and "adaptive relaxation" which modulates gastric tone in response to the specific properties of the meal ingested. However, there are considerable technical difficulties in measuring the accommodation process. The current standard barostat studies, and other methods such as conventional and three dimensional ultrasound, or single photon emission computed tomography have significant disadvantages. Preliminary findings from the development and validation of a new magnetic resonance imaging technique that addresses many of the deficiencies of previous methods are presented.

Glucagon-like peptide-2 inhibits antral emptying in man, but is not as potent as glucagon-like peptide-1

BACKGROUND

GLP-1 (glucagon-like peptide-1) and GLP-2 (glucagon-like peptide-2) are released in equimolar amounts in response to meal ingestion. GLP-1 inhibits gastric emptying and reduces postprandial gastric and exocrine pancreatic secretion and may play a physiological regulatory role in controlling appetite and energy intake in humans. The role of GLP-2 is more uncertain. Based on the results of animal studies, it has been suggested that GLP-2 may induce intestinal epithelial growth and inhibit gastric motility. The aim of this study was to determine to what extent GLP-2 alone or together with GLP-1 inhibits gastric emptying and the sensation of hunger in man.

METHODS

Eight healthy volunteers were tested in a double-blind, placebo-controlled fashion. Antral emptying of a liquid meal and hunger ratings were determined using ultrasound technology and visual analogue scales scoring during infusions of saline, GLP-2 (0.5, and 1.0 pmol kg body wt(-1) min(-1)), GLP-1 (0.5 pmol kg body wt(-1) min(-1)) or GLP-1 and GLP-2 (0.5 pmol kg body wt(-1) min(-1)).

RESULTS

The GLP-2 infusions resulted in a dose-dependent increase in antral emptying time (35%; ns and 75%; P = 0.049) compared to saline, but GLP-2 was less potent than GLP-1, which increased the antral emptying time by 192% (P < 0.001). Addition of GLP-2 to the GLP-1 infusion did not alter the antral emptying time compared with GLP-1 alone. The GLP-1 infusion decreased the sensation of hunger compared with saline (P = 0.023), whereas the two GLP-2 infusions had no significant effect. Addition of GLP-2 to the GLP-1 infusion did not decrease the sensation of hunger further.

CONCLUSIONS

Both GLP-1 and GLP-2 inhibit antral emptying in man, but GLP-1 is more potent.

Motor function of gastric antrum and pylorus for evacuation of low and high viscosity meals in dogs

In five conscious dogs motility of the antrum, pyloric sphincter, and duodenum was recorded with strain gauge transducers and induction coils. Gastric evacuation of low, medium, and high viscosity meals was measured via a duodenal cannula and observed simultaneously by radiography. Computer analysis of the propagation of the gastric waves revealed increased velocity in the distal antrum but no simultaneous contractions of the terminal antrum and pyloric sphincter. Radiography showed, and measurements of the antral diameter confirmed, that the indentations of the gastric waves were significantly deeper with the low viscosity liquid meal compared with the medium and high viscosity meals. Thereby, retropulsion of the medium and high viscosity ingesta was produced. Results indicated that gastric evacuation was regulated predominantly by the depth of the peristaltic indentation, which depended on the viscosity of the gastric contents. Nothing indicated that the phasic contractions of the pyloric sphincter were of importance for the regulation of gastric emptying.

Relation between antral motility and gastric emptying of solids and liquids in humans

Our aim was to test the hypothesis that there is a relation between antral phasic pressure activity and the emptying of solids and liquids from the intact human stomach after a mixed meal. This hypothesis was evaluated in 14 healthy individuals in whom we performed simultaneous antral manometry and radioscintigraphy after ingestion of a meal labeled with [99mTc]sulfur colloid in cooked egg (solid component) and [111In]DTPA (liquid component). Analysis of the data included an in-depth evaluation of different models for expressing both gastric emptying rates and antral pressure activity. We found that gastric emptying was adequately represented by a two-phase model consisting of lag and emptying periods and by a power exponential model for the liquid phase. Distal antral motility was accurately represented by the slope of the cumulative antral motility index. During the lag period for solids, the antral motility was inversely related to the duration of the lag. During the solid-emptying period, there was a positive correlation between emptying of solids and antral motility. No significant relation was found between antral motility and overall emptying of the liquid phase of the meal. However, a relationship was found when antral motility was related to liquid emptying after an initial lag period for solids. These human data are consistent with a role of antral pressure activity in trituration of solid food and a role of the antrum in the subsequent propulsion of solids and liquids from the stomach.

Gastroduodenal motility during the delayed gastric emptying induced by cold stress

We have assessed the changes in gastroduodenal motility responsible for the delay in gastric emptying produced by cold stress. Antropyloroduodenal pressures were recorded in 7 healthy volunteers, concurrent with scintigraphic measurement of gastric emptying. The manometric assembly incorporated a sleeve sensor located across the pylorus and side holes in the antrum and the duodenum. When approximately 25% of a 100-g 99m Tc-labeled ground beef burger had emptied from the stomach, a standardized cold pressor test was applied. This consisted of 60-s immersions of the left hand in iced water (4 degrees C), with 15-s rest periods between immersions, for up to 20 min. Cold stress was associated with slowed emptying from the total stomach (median, 17% before stress vs. 2% during stress; p less than 0.01) and the proximal stomach (9% before vs. 3% during; p less than 0.01). Retrograde movement of the solid meal from the distal to the proximal stomach was observed in 4 subjects. Cold stress increased the number of isolated pyloric pressure waves (p less than 0.05), and decreased the number of antral (p less than 0.01) and propagated antropyloroduodenal pressure waves (p less than 0.05). Phase 3-like duodenal activity occurred in 2 subjects during the first 5 min of stress; otherwise there was a reduction in the number of duodenal pressure waves during stress (p less than 0.05). Basal pyloric pressure was not elevate before, during, or after stress. We conclude that in addition to the previously reported antral inhibition, cold stress is associated with changes in pyloric and duodenal motility and, in some subjects, in the intragastric distribution of food. These modifications in gastroduodenal motility are likely to contribute to the delay in gastric emptying produced by this stimulus.

Comparison of total and compartmental gastric emptying and antral motility between healthy men and women

There is increasing evidence of gender-related differences in gastric emptying. The purpose of this study was first, to confirm the difference in gastric emptying for both solid and liquid test meals between healthy men and women, and secondly, to investigate the origin of this difference by studying regional gastric emptying and antral motility. A standard gastric emptying test with additional compartmental (proximal and distal) evaluation and dynamic imaging of the antrum was performed in 20 healthy women studied during the first 10 days of the menstrual cycle, and in 31 healthy age-matched men. In concordance with previous reports, women had a longer half-emptying time for solids as compared to men (86. 2+/-5.1 vs 52.2+/-2.9 min, P<0.05). In our observations this seemed to be related to a significantly prolonged lag phase and a significant decrease in terminal slope. Dynamical antral scintigraphy did not show a significant difference. The distribution of the test meal within the stomach (proximal vs distal) showed more early proximal retention in women as compared to men. The terminal slope of the distal stomach was significantly lower in women. We did not observe a significant difference in gastric emptying of the liquid test meal between men and women. Gastric emptying of solids is significantly slower in healthy women as compared to men. These findings emphasise the importance of using different normal values for clinical and research purposes in gastric emptying scintigraphy in men and women. The difference could not be explained by antral motility alone. Increased proximal retention and a lower terminal emptying rate in women are observations to be further investigated.

Motilin induces gall bladder emptying and antral contractions in the fasted state in humans

BACKGROUND

Animal studies have shown that motilin affects gall bladder motility. In humans, no effect has been shown, but erythromycin, a motilin receptor agonist, induces gall bladder emptying.

AIMS

To explore the effect of increasing doses of exogenous motilin on gall bladder volume and antral contractility in the fasted state in humans.

METHODS

After an overnight fast, eight healthy men received increasing intravenous doses of Leu13-motilin (KW-5139) or 0.9% NaCl in a double blind, randomised fashion. Gall bladder volume and antral contraction frequency were determined by ultrasonography.

RESULTS

Infusion of motilin increased plasma motilin levels. Motilin induced a reduction in gall bladder volume of 8.0 (5.0)%, 17.1 (5.0)%, 18.5 (4.7)%, and 16.1 (4.9)% of baseline volume at the end of infusion of 2, 4, 8, and 16 pmol/kg/min respectively, compared with mean stable gall bladder volumes during placebo infusion (p < 0.05). Antral contraction frequency increased during motilin infusion, but not during placebo infusion (p < 0.05).

CONCLUSIONS

Exogenous motilin reducted fasting gall bladder volume and increased antral contractions. After reaching maximal reduction, the gall bladder volume did not decrease further during continuous motilin infusion at higher doses and stayed at the same reduced volume. The degree of gall bladder volume reduction during motilin infusion mimicked gall bladder emptying preceding antral phase III activity of the migrating motor complex in humans. This study indicates that motilin may play a physiological role in the regulation of gall bladder emptying in the fasted state.

Intravenous cisapride accelerates delayed gastric emptying and increases antral contraction amplitude in patients with primary anorexia nervosa

Delayed gastric emptying is common in primary anorexia nervosa. We investigated in 12 patients whether gastric emptying could be accelerated by the prokinetic drug cisapride. Patients were studied on two occasions 1 wk apart and received, under random double-blind conditions, 8 mg of cisapride and placebo intravenously. Gastric emptying of an isotopically labeled semisolid meal and antral motor activity were measured using a dual-headed gamma-camera for 50 min. Emptying was significantly slower (half-emptying time, 50-191 min; median, 121 min) than in 24 healthy volunteers (half-emptying times, 21-119 min; median, 47 min). Cisapride accelerated emptying significantly (p less than 0.001; half-emptying time after cisapride, 22-80 min; median, 42 min). Antral contraction amplitude increased and contraction frequency decreased significantly (p less than 0.001), whereas the propagation velocity of contractions remained unchanged. We concluded that intravenous cisapride accelerates gastric emptying and increases antral contraction amplitude in patients with anorexia nervosa. Whether or not these effects can prove beneficial in diminishing the patients' symptoms and in helping them to gain weight can only be answered from studies involving long-term treatment with cisapride.

Antroduodenal motility studied by real-time ultrasonography. Effect of enprostil

Transabdominal real-time ultrasonography was used to investigate antroduodenal motility effects of the prostaglandin E2 analogue enprostil. Ten healthy subjects were studied on two separate days, once after oral administration of one capsule of enprostil 35 micrograms 1 hour before the ingestion of 500 mL of meat soup and once without drug administration before the meal. The ultrasound probe was positioned at the level of the transpyloric plane to visualize the antrum, pylorus, and proximal duodenum simultaneously and thereafter vertically to visualize the antrum, superior mesenteric vein, and aorta simultaneously. The motility was videotaped for 15 minutes. The antroduodenal coordination, frequency and amplitude of antral contractions, and size of antral area were reduced, whereas the time during which the pylorus was wide open (greater than 5 mm) was increased after enprostil. It is concluded that antroduodenal motility can easily be visualized by ultrasonography. Therapeutic doses of enprostil impair antroduodenal peristalsis and coordination and open the pylorus in healthy subjects.

Antral motility in patients with cirrhosis with or without gastric antral vascular ectasia

Gastric motility has not been extensively studied in patients with cirrhosis and gastric antral vascular ectasia (GAVE) may be associated with antropyloric dysfunction. This study therefore looked at antral motility using ultrasound in patients with alcoholic cirrhosis with or without GAVE. Twenty six patients were included: 10 patients with cirrhosis without GAVE, eight patients with cirrhosis and GAVE, and eight controls without liver disease. Measurement of antral area and antral contractions (amplitude and frequency) was performed for three hours after ingestion of a standardised solid-liquid meal. Antral area half time (mean (SD)) was not significantly increased in patients with cirrhosis without GAVE (84 (42) min), but increased by 120% (123 (43) min; p < 0.01) in patients with GAVE compared with controls (56 (26) min). GAVE patients exhibited the same frequency and amplitude of antral contractions at each time point as controls and had the same tendency to increase these values over time although this was attenuated in the late postprandial phase. In contrast, cirrhotic patients without GAVE exhibited a significantly higher frequency and amplitude of antral contractions during the initial postprandial phase but showed no change in either frequency or amplitude over time. In conclusion, in cirrhosis there is an abnormal antral motor response to a meal, which has a different pattern over time in patients with or without GAVE.

Gastrointestinal wall thickness measured with transabdominal ultrasonography and its relationship to demographic factors in healthy subjects

PURPOSE

To describe the gastrointestinal (GI) wall thickness and the thickness of individual wall layers in healthy subjects using ultrasound and to determine whether demographic factors, the ultrasound transducer frequency, or a fasting state influences these measurements.

MATERIALS AND METHODS

After overnight fasting, the GI wall thickness and wall layers were measured in several regions with transabdominal, high-frequency ultrasound. 122 healthy subjects aged 23 - 79 were included. All measurements were performed with both 8 and 12-MHz transducers except for the rectum measurement (4 MHz). 23 patients were given a 300 Kcal test meal and re-examined after 30 minutes.

RESULTS

Wall thickness measurements of the GI tract with transabdominal ultrasonography are dependent on transducer frequency (p < 0.001), weight (p < 0.001) and age (p < 0.018). The thickness of individual wall layers in the ileum and the sigmoid colon was found to be dependent on both age (p = 0.007) and weight (p < 0.001). The mean wall thickness from the jejunum to the sigmoid colon ranged from 0.9 to 1.2 mm with standard deviations (SD) of 0.3 mm or less. The mean (SD) was 2.9 (0.8) mm in the gastric antrum, 1.6 (0.3) mm in the duodenum, and 2.1 (0.5) mm in the rectum. The gastric antrum was thinner and the ileum and sigmoid colon were thicker after the test meal (p < 0.05).

CONCLUSION

GI wall thickness depends on weight and age. Provided adequate measurement, an abnormal GI wall should be suspected if the thickness exceeds 2 mm except for in the gastric antrum, duodenum and rectum. Reference values for wall thickness can be used regardless of fasting state or probe frequency except for in the gastric antrum.

Ultrasound measurement of gastric emptying time in patients with cystic fibrosis and effect of ranitidine on delayed gastric emptying

Intestinal dysmotility is commonly reported in patients with cystic fibrosis (CF); however, gastric motor activity has rarely been investigated. We measured with real-time ultrasonography the antral distention and gastric emptying time of a solid-liquid meal in 29 patients with CF (age range, 5 to 17 years). A significantly prolonged gastric emptying time was present in 26 patients compared with 13 healthy control subjects (age range, 5 to 16 years); an exaggerated antral distention in the fed period was also detected. The patients with CF and delayed gastric emptying were randomly allocated to receive cisapride or ranitidine for 4 weeks. Twelve patients treated with ranitidine and 11 with cisapride completed the trial. There was a marked decrease in gastric emptying time, antral distention, and dyspeptic symptomatic score in patients receiving ranitidine but not in patients treated with cisapride. We conclude that gastric dysmotility is commonly detected in patients with CF and that H2 receptor blockers are more effective than prokinetics in improving dyspeptic symptoms and gastric emptying and distention.

Gastric emptying and gastro-oesophageal reflux in preterm infants

Gastro-oesophageal reflux is common in preterm infants, but the role of gastric emptying as a causal factor has not been studied before. Gastric emptying was therefore measured in 19 healthy preterm infants (median gestational age 32 weeks) while concurrently measuring 24 hour lower oesophageal pH, using an antimony pH electrode, positioned manometrically. Real time ultrasonic images of the gastric antrum were obtained, and measurements of antral cross-sectional area (ACSA) were made immediately before a nasogastric feed and then during subsequent gastric emptying until ACSA returned to its pre-feed value. Half emptying time (50% delta ACSA) was calculated as the time taken for the ACSA to fall to half the maximal postprandial increment. Mean (SEM) reflux index for the group was 11.9 (2.0)%; number of reflux episodes per 24 hours: 15.4 (1.7); and number of reflux episodes longer than five minutes 5.5 (0.8). Average half emptying times for an individual infant were: median (range) 46 (18-105) minutes. There was no association between gastric emptying rates and any of the indices of gastro-oesophageal reflux, either during the entire 24 hour period for which the lower oesophageal pH was recorded, or in the postprandial periods after the feeds which were studied ultrasonically. Gastro-oesophageal reflux was also unrelated to feed volume and feed type. Asymptomatic gastro-oesophageal reflux is common in preterm infants, but gastric emptying time is not a determinant of it. Inappropriate relaxation of the lower oesophageal sphincter or abnormal oesophageal motility offer more plausible explanations.

CT of gastric carcinoma: preliminary results with a new scanning technique

Usefulness of computed tomography (CT) for the demonstration of gastric carcinoma was evaluated in 250 cases with surgical proof of diagnosis: advanced gastric carcinoma (n = 193), early gastric carcinoma (n = 47), gastric submucosal tumor (n = 8), gastric polyp (n = 1), and benign gastric ulcer (n = 1). CT was performed on prone patients after 400-600 mL of water was orally administered and a 100-mL bolus of nonionic contrast material was injected. Water provided optimal distention and satisfactory contrast to depict the normal gastric wall. Prone positioning allowed visualization of the whole gastric wall except for the fundus and prevented artifacts caused by gas during supine imaging. CT demonstrated gastric tumor as a thickened or abnormally enhanced gastric wall in 95% of advanced carcinomas, 93% of elevated early carcinomas, and 18% of depressed early carcinomas. The authors believe that CT performed with this method is useful and that it should be used in addition to barium and endoscopic studies before surgery is planned.

Ultrasonic assessment of gastric emptying in the preterm infant

The study of gastric emptying in the preterm infant has been hampered by the absence of a suitable, valid technique. We have evaluated gastric antral clearance using serial ultrasonic measurement of the antral cross sectional area (ACSA). The study was easy to perform, providing successful results in 15 of 17 low birth-weight infants, with feed volumes of 8-31 ml/kg. ACSA was closely related to intragastric volume (mean (range) r = 0.96 (0.89-0.99)). Measurements were reproducible: mean (SE) coefficient of variation was 7.7% (1.1). Gastric antral clearance was observed as a fall in ACSA that began shortly after completion of the feed and returned to prefeed values at a variable rate. The pattern of gastric antral transit was entirely consistent with recognised patterns of gastric emptying and half gastric antral clearance times ranged from 20-63 minutes. Ultrasonic measurement of gastric antral clearance is a new technique allowing the study of gastric emptying in the preterm infant.