Dynamic antral scintigraphy following solid and liquid meals in healthy human subjects

A novel dynamic scintigraphic technique for assessing duodenal contractions during gastric emptying in humans: a feasibility study

Duodenal contractions are thought to play a role in the control of gastric emptying. Although noninvasive techniques, such as ultrasonography and MRI, have been proposed for studying duodenal contractile activity in humans, there are no reports on the use of scintigraphy for this purpose. This work aimed to describe a novel scintigraphic technique for assessing duodenal contractility during gastric emptying in humans, and to present preliminary data on the frequency and amplitude of contractions detected in three different duodenal segments. Fasted young healthy volunteers (N=12) were given either a liquid or a solid test meal of similar calorie content (400 kcal) labeled with 99mTc-phytate. Static images were collected to determine gastric emptying. Dynamic images of the anterior aspect of the abdomen (1 frame/s) were also acquired periodically in a standard position for 256 s at 15-30 min intervals. 'Activity versus time' curves were generated for regions of interest corresponding to the proximal, middle, and distal duodenal segments. Curves were digitally filtered and processed to estimate both dominant frequency (fast Fourier transform) and amplitude (mean ejection fraction) of postprandial duodenal contractions. There were no significant differences regarding dominant frequency among proximal, middle, and distal duodenal regions of interest. In addition, there were no significant differences between the liquid and the solid meal in terms of either frequency or amplitude of duodenal contractions. Characterization of duodenal contractions in humans using scintigraphy is feasible and yields consistent data for both the frequency and the amplitude of postprandial contractions, which seems to be rather independent of meal consistency.

Radionuclide gastric emptying scintigraphy in patients with functional dyspepsia

AIM: To assess the use of gastric emptying scintigraphy with solid test meal in patients with functional dyspepsia (FD) and normal subjects.

METHODS: Forty-two patients with FD and 30 normal subjects underwent gastric emptying scintigraphy with 99mTc-DTPA labeling egg solid meal. The standard curve of gastric emptying was plotted to figure out the half-time of gastric emptying and emptying rate at 60 and 120 min by three different methods: method 1 with the radioactivity of the anterior view, method 2 with the mean value of and method 3 with the geometric mean of the radioactivity of the anterior and pastier views as the y-axis of the standard curve of gastric emptying, respectively. The differences in half-times and gastric emptying rates at 60 and 120 min figured out by the three different methods were compared between patients with FD and normal subjects.

RESULTS: One-way analysis of variance was performed to compare the differences in half-times. The half-time figured out by method 1 did not differ significantly from that by method 2 (P = 0.808, P = 0.243, P > 0.05), but the half-time figured out by method 3 differed significantly from those by methods 1 and 2 (1 vs 3: P = 0.007, P = 0.000; 2 vs 3: P = 0.035, P = 0.023; P < 0.05 for all). The half-time and gastric emptying rates at 60 and 120 min differed significantly between FD patients and normal subjects (P = 0.000). Method 1 figured out 80.9%, method 2 figured out 71.4% and method 3 figured out 90.5% of FD patients had longer half-time than normal subjects.

CONCLUSION: Radionuclide 99mTc-DTPA gastric emptying scintigraphy with solid meal is a simple, accurate, quantitative and physiologic method for measuring gastric motility in FD patients.

Advancing gastric emptying studies: standardization and new parameters to assess gastric motility and function

For many years, gastric emptying (GE) studies were performed using various local protocols and different radiolabeled meals. This lack of standardization and normal values made the test results unreliable and difficult to compare from one site to another. A recent consensus has been published that now provides guidance and standardization on how to perform a radiolabeled solid-meal GE study. It is widely recognized, however, that simple measurement of total GE of a solid meal often does not provide an answer to the etiology of symptoms for a large number of patients who present with functional dyspepsia. Advances in our understanding of the different roles of the fundus and antrum and their complex interaction with the proximal small bowel and central nervous system have led to the development of new methods to study gastric motility. This review describes how a more comprehensive approach to studying GE is needed and how this will lead to better diagnosis and treatment for patients referred for GE studies.

Influence of gastric acid on gastric emptying and gastric distension-induced pain response in rats--effects of famotidine and mosapride

BACKGROUND

Gastroduodenal acidification has been reported to aggravate upper abdominal discomfort and pain that are symptoms suffered by functional dyspepsia (FD) patients. Delayed gastric emptying and hypersensitivity to gastric distension (GD) contribute importantly to the pathophysiology of FD.

METHODS

In the present study, we determined the influence of pentagastrin-stimulated endogenous gastric acid on gastric emptying and GD-induced pain responses using rat model systems. Moreover, we evaluated the effects of famotidine and mosapride on changes in gastric emptying and the GD-induced pain response to gastric acid hypersecretion. Gastric emptying was measured by excretion of glass beads that had been intragastrically administered with a liquid nutrient, and gastric pain response was evaluated by observing whether a GD-induced increase in mean blood pressure occurred.

KEY RESULTS

Pentagastrin (2 mg kg(-1), s.c.) which markedly and continuously stimulated gastric acid secretion, significantly delayed and enhanced respectively, gastric emptying and pain compared with saline-injected groups. Oral famotidine (0.1-3 mg kg(-1)) and mosapride (0.3-3 mg kg(-1)) administration in a dose-dependent manner accelerated the delay of gastric emptying. Furthermore, famotidine (0.3-3 mg kg(-1)) significantly alleviated the aggravation of the GD-induced pain response, but mosapride (10 mg kg(-1)) did not.

CONCLUSIONS & INFERENCES

We established rat models to evaluate the effect of gastric acid hypersecretion on gastric emptying and the GD-induced pain response. In these models, acid hypersecretion delayed gastric emptying and aggravated the pain response. Furthermore, we showed that famotidine ameliorated both delayed gastric emptying and gastric hypersensitivity, whereas mosapride only improved delayed gastric emptying.

Methods for measurement of gastric motility

There is an array of tests available to measure gastric motility. Some tests measure end points, such as gastric emptying, that result from several different functions, whereas other tests are more specific and test only a single parameter, such as contractility. This article reviews the tests most commonly available in practice and research to evaluate in vivo the gastric functions of emptying, accommodation, contractility, and myoelectrical activity. The rationale for testing, the relative strengths and weaknesses of each test, and technical details are summarized. We also briefly indicate the applications and validations of the tests for use in experimental animal studies.

Comparison between manual and automated techniques for assessment of data from dynamic antral scintigraphy

OBJECTIVE

This work aimed at determining whether data from dynamic antral scintigraphy (DAS) yielded by a simple, manual technique are as accurate as those generated by a conventional automated technique (fast Fourier transform) for assessing gastric contractility.

METHODS

Seventy-one stretches (4 min) of "activity versus time" curves obtained by DAS from 10 healthy volunteers and 11 functional dyspepsia patients, after ingesting a liquid meal (320 ml, 437 kcal) labeled with technetium-99m (99mTc)-phytate, were independently analyzed by manual and automated techniques.

RESULTS

Data obtained by both techniques for the frequency of antral contractions were similar. Contraction amplitude determined by the manual technique was significantly higher than that estimated by the automated method, in both patients and controls. The contraction frequency 30 min post-meal was significantly lower in patients than in controls, which was correctly shown by both techniques.

CONCLUSIONS

A manual technique using ordinary resources of the gamma camera workstation, despite yielding higher figures for the amplitude of gastric contractions, is as accurate as the conventional automated technique of DAS analysis. These findings may favor a more intensive use of DAS coupled to gastric emptying studies, which would provide a more comprehensive assessment of gastric motor function in disease.

Postprandial gastric antral contractions in patients with gastro-oesophageal reflux disease: a scintigraphic study

Disturbed gastric contractility has been found in manometric studies in patients with gastro-oesophageal reflux disease (GORD), but the pathophysiological role of this abnormality is unclear. We aimed at assessing postprandial gastric antral contractions and its relationships with gastric emptying and gastro-oesophageal reflux in GORD patients. Fasted GORD patients (n = 13) and healthy volunteers (n = 13) ingested a liquid meal labelled with 72 MBq of 99mTechnetium-phytate. Gastric images were acquired every 10 min for 2 h, for measuring gastric emptying half time. Dynamic antral scintigraphy (one frame per second), performed for 4 min at 30-min intervals, allowed estimation of both mean dominant frequency and amplitude of antral contractions. In GORD patients (n = 10), acidic reflux episodes occurring 2 h after the ingestion of the same test meal were determined by ambulatory 24-h oesophageal pH monitoring. Gastric emptying was similar in GORD patients and controls (median; range: 82 min; 58-126 vs 80 min; 44-122 min; P = 0.38). Frequency of antral contractions was also similar in both groups (3.1 cpm; 2.8-3.6 vs 3.2 cpm; 2.4-3.8 cpm; P = 0.15). In GORD patients, amplitude of antral contractions was significantly higher than in controls (32.7%; 17-44%vs 23.3%; 16-43%; P = 0.01), and correlated positively with gastric emptying time (R(s) = 0.58; P = 0.03) and inversely with the number of reflux episodes (R(s) = -0.68; P = 0.02). Increased amplitude of postprandial gastric antral contractions in GORD may comprise a compensatory mechanism against delayed gastric emptying and a defensive factor against acidic gastro-oesophageal reflux.