Use of scintigraphy to evaluate gastric accommodation and emptying: comparison with barostat

Scintigraphy of Gastrointestinal Motility: Best Practices in Assessment of Gastric and Bowel Transit in Adults

Various radiologic examinations and other diagnostic tools exist for evaluating gastrointestinal diseases. When symptoms of gastrointestinal disease persist and no underlying anatomic or structural abnormality is identified, the diagnosis of functional gastrointestinal disorder is frequently applied. Given its physiologic and quantitative nature, scintigraphy often plays a central role in the diagnosis and treatment of patients with suspected functional gastrointestinal disorder. Most frequently, after functional gallbladder disease is excluded, gastric emptying scintigraphy (GES) is considered the next step in evaluating patients with suspected gastric motility disorder who present with upper gastrointestinal symptoms such as dyspepsia or bloating. GES is the standard modality for detecting delayed gastric emptying (gastroparesis) and the less commonly encountered clinical entity, gastric dumping syndrome. Additionally, GES can be used to assess abnormalities of intragastric distribution, suggesting specific disorders such as impaired fundal accommodation or antral dysfunction, as well as to evaluate gastric emptying of liquid. More recently, scintigraphic examinations for evaluating small bowel and large bowel transit have been developed and validated for routine diagnostic use. These can be performed individually or as part of a comprehensive whole-gut transit evaluation. Such scintigraphic examinations are of particular importance because clinical assessment of suspected functional gastrointestinal disorder frequently fails to accurately localize the site of disease, and those patients may have motility disorders involving multiple portions of the gastrointestinal tract. The authors comprehensively review the current practice of gastrointestinal transit scintigraphy, with diseases and best imaging practices illustrated by means of case review. ©RSNA, 2024 See the invited commentary by Maurer and Parkman in this issue.

A novel MRI-based three-dimensional model of stomach volume, surface area, and geometry in response to gastric filling and emptying

BACKGROUND

Gastric motility and accommodation have a critical role in maintaining normal gastrointestinal homeostasis. Different modalities can be adopted to quantify those processes, that is, scintigraphy to measure emptying time and intragastric Barostat for accommodation assessment. However, magnetic resonance imaging (MRI) can assess the same parameters noninvasively without ionizing radiation. Our study aimed to develop a detailed three-dimensional (3D) MRI model of the stomach to describe gastric volumes, surface areas, wall tension distribution, and interobserver agreement.

METHODS

Twelve healthy volunteers underwent an MRI protocol of six axial T2-weighted acquisitions. Each dataset was used to construct a 3D model of the stomach: First, the volumes of the whole stomach, gastric liquid, and air were segmented. After landmark placing, a raw 3D model was generated from segmentation data. Subsequently, irregularities were removed, and the model was divided into compartments. Finally, surface area and 3D geometry parameters (inverse curvatures) were extracted. The inverse curvatures were used as a proxy for wall tension distribution without measuring the intragastric pressure.

KEY RESULTS

The model was able to describe changes in volume and surface geometry for each compartment with a distinct pattern in response to filling and emptying. The surface tension was distributed nonhomogeneously between compartments and showed dynamical changes at various time points.

CONCLUSION & INFERENCES

The presented model offers a detailed tool for evaluating gastric volumes, surface geometry, and wall tension in response to filling and emptying and will provide insights into gastric emptying and accommodation in diseases such as diabetic gastroparesis.

A Preclinical Feasibility Study of Endoscopic Barostat: A Possible Diagnostic Tool for Visceral Hypersensitivity in Functional Dyspepsia

INTRODUCTION

Diagnosing functional dyspepsia requires excluding organic disease and gastrointestinal function evaluation; however, there are no modalities to evaluate these simultaneously. This preclinical study examined the possibility of an endoscopic barostat.

METHODS

Ultrathin endoscopy and our newly developed pressure-regulated endoscopic insufflator, which insufflates the gastrointestinal tract until the preset pressure is achieved, were used. The actual intragastric pressure was measured using an optical fiber manometer placed in the stomach. Experiment-1: in an ex vivo experiment, we insufflated the isolated stomach and verified whether the intragastric pressure reached the preset pressure. Experiment-2: we inserted the endoscope orally in a porcine stomach, insufflated the stomach, and verified whether the intragastric pressure reached the preset pressure. Finally, we insufflated the stomach at a random pressure to verify the functional tests for proof-of-concept.

RESULTS

Experiment-1: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.015, regression line: 0.988, 95% confidence interval [CI]: 0.994-0.994). Experiment-2: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.018, regression line: 0.971, 95% CI: 0.985-0.986). At randomly preset pressures, the transendoscopic theoretical intragastric pressure detected by using the insufflator was correlated with the actual pressure measured by using the pressure manometer.

CONCLUSIONS

This proof-of-concept study shows that a pressure-regulated endoscopic insufflator provides stable intragastric pressure at the preset level, with the potential of an endoscopic barostat to assess the visceral hypersensitivity related to functional dyspepsia.

The effect of prucalopride on gastric sensorimotor function and satiation in healthy volunteers

BACKGROUND

Gastric motor function alterations have been implicated in the pathogenesis of functional dyspepsia with postprandial distress syndrome (PDS). Prucalopride, a 5-TH4 agonist, is known to stimulate gastrointestinal motility. We aimed to evaluate the effect of prucalopride on gastric sensorimotor function in healthy subjects (HV).

METHODS

Barostat and intragastric pressure (IGP) measurements were performed in 17 HV (59% females, age 29.4 ± 2.7 y) after treatment with placebo or prucalopride (2 mg) (single-blind cross-over). Isobaric stepwise distensions and gastric sensations were assessed to determine gastric compliance and sensitivity. Gastric accommodation (GA) with the barostat was quantified before and after ingestion of 200 ml of a nutrient drink (ND). GA measured by IGP was quantified as the drop of IGP from baseline during the intragastric infusion of ND until maximal satiation (60 ml/min).

KEY RESULTS

Prucalopride did not affect barostat assessed gastric compliance or sensitivity. No differences were observed in GA after prucalopride. During the barostat study, 10 min after the meal, 7 HVs reported significantly higher ratings for nausea after prucalopride (p < 0.001), and vomiting was induced in 4 of the HVs. A positive correlation was observed between the delta mean perception of nausea with the delta mean increase of intra-balloon volume before and after meal ingestion (r = 0.37, p = 0.03). During IGP measurements, no effect on nutrient tolerance was observed and increased cramp severity scores were observed which were associated with a significant increase of distal IGP (r = 0.78, p < 0.0001).

CONCLUSIONS & INFERENCES

Prucalopride does not enhances gastric accommodation but it might increase sensitivity to gastric distention. Furthermore, the increase in sensitivity seems to be related to an increase in nausea with distension. Clinicaltrials.gov: NCT04429802.

Joint Hypermobility Syndrome in Patients With Functional Dyspepsia

INTRODUCTION:

The pathophysiology underlying functional dyspepsia (FD) is multifactorial and focuses on gastric sensorimotor dysfunction. Recent studies demonstrated that joint hypermobility syndrome (JHS) is strongly associated with unexplained dyspeptic symptoms in patients attending gastrointestinal clinics. We aimed to study the relationship between symptoms, gastric sensorimotor function, and JHS in FD patients.

METHODS:

Tertiary care FD patients who underwent a gastric barostat study and a gastric emptying breath test with 13C-octanoic acid were recruited for assessment of JHS. The presence of JHS was evaluated by a 2-phase interview and clinical examination that included major and minor criteria of the Brighton classification.

RESULTS:

A total of 62 FD patients (68% women, age 44 ± 1.8 years, and body mass index: 21.7 ± 0.7 kg/m²) accepted to participate in the study. JHS was diagnosed in 55% of FD patients. Assessed symptom profiles during the visit did not differ between the groups. Delayed gastric emptying was not significantly more common in JHS group compared with non-JHS group (JHS group 32% vs non-JHS group 16%, P = 0.31). Prevalence of hypersensitivity to distention (JHS group 24% vs non-JHS group 29%, P = 0.76) and impaired gastric accommodation (JHS group 38% vs non-JHS group 42%, P = 0.79) was similar in patients with or without JHS. No correlations were found between the Beighton hypermobility score and gastric compliance (r = 0.09).

DISCUSSION:

A large subset of this study cohort of tertiary care FD patients has coexisting JHS. We did not identify any specific differences in gastric sensorimotor function between patients with and without JHS. Further prospective research will be required to elucidate the relationship between JHS, a multisystemic disorder with widespread manifestations, and FD symptoms.

Enhancing Scintigraphy for Evaluation of Gastric, Small Bowel, and Colonic Motility

This article reviews the latest enhancements in standards and technology for performing gastric emptying and associated small bowel and colon transit scintigraphic studies. It discusses how developments in appropriate use criteria, American Medical Association Current Procedural Terminology coding, and advanced commercial software permit clinicians to obtain more comprehensive physiologic studies of gastric, small bowel, and colon gastrointestinal motility disorders. It shows how gastrointestinal scintigraphy has expanded to permit assessments of global and regional (fundic and antral) gastric motility and how it permits a single study (whole-gut transit scintigraphy), including measurement of solid and liquid gastric emptying and small bowel and colon transit.

Evaluation of Gastric Emptying by Transabdominal Ultrasound after Oral Administration of Semisolid Cellulose-Based Gastric Ultrasound Contrast Agents

Many previous studies have found that transabdominal ultrasound may allow precise measurement of gastric emptying of liquid meals. However, the clinical use of this technique has been hampered by the limitation that transabdominal ultrasound might not accurately measure gastric emptying of solid meals. It is more important to measure gastric emptying of solids instead of liquids, as gastric emptying of solids is more often delayed than gastric emptying of liquids in gastric motility disorders. Recently, transabdominal ultrasound after oral administration of a cellulose-based gastric contrast agents (TUS-OSCA) has been suggested to be effective in initial screening of gastric lesions. The aim of this study was to explore the accuracy of TUS-OSCA in the evaluation of gastric emptying of a semisolid meal. Twenty healthy young patients (10 males and 10 females aged 25.5 ± 2.5 y) were studied. Concurrent measurements of gastric emptying by scintigraphy and TUS-OSCA were performed after ingestion of 350 mL semisolid ultrasound agent labeled with 20 MBq ^99mTc-sulfur colloid. There was no significant difference in the overall curves for gastric emptying time between scintigraphy and TUS-OSCA. There was a good correlation between the gastric 50% emptying times determined by scintigraphy (89.4 ± 1.8 min) and TUS-OSCA (92.5 ± 1.7 min). The correlation coefficient was r = 0.922 (p = 0.000). Current results indicate that TUS-OSCA is accurate, and the results are similar to those obtained by scintigraphy for gastric emptying of a semisolid meal.

Enhanced Gastric Emptying Scintigraphy to Assess Fundic Accommodation Using Intragastric Meal Distribution and Antral Contractility

Gastric emptying scintigraphy (GES) as now commonly performed measures only total gastric emptying. Intragastric meal distribution (IMD) immediately after meal ingestion (t = 0 min) (IMD⁰) can assess fundic accommodation, and dynamic antral contraction scintigraphy (DACS) can assess antral motility. Our goals were to incorporate IMD and DACS into GES, compare IMD⁰ using gastric division into anatomic proximal and distal halves versus more physiologic separation of the antrum from the proximal stomach using DACS, and establish reference values. Methods: Healthy subjects (n = 20) underwent GES using a solid-liquid meal. DACS (1 frame/3 s) was performed for 20 min after each static imaging time. IMD⁰ was measured using both semiautomated software to divide the gastric long axis into anatomic halves and Fourier analysis to identify antral pixels with phasic contractions. Results: Using halving of the stomach, IMD⁰ averaged 0.75 ± 0.15 (SD). Using phasic contractions to define the antrum, mean IMD⁰ was 0.85 ± 0.14 (P = 0.004). Sustained antral contractions started at a mean of 11.24 ± 12.98 min after meal ingestion and originated in the gastric midbody with a starting location at 40.5% ± 10.8% from the distal to the proximal stomach along its long axis. Antral frequency and ejection fraction peaked 30 min after meal ingestion at 3.30 ± 0.71 contractions per minute and an ejection fraction of 30.3% ± 13.69%, when mean antral filling peaked at 36.7% ± 14%. Maximum antral contraction speed was 3.54 ± 0.90 mm/s at 60 min after meal ingestion. Gastric retention was 39.8% ± 12.8% at 2 h and 5.8% ± 6.0% at 4 h. Conclusion: Addition of DACS to GES permits physiologic characterization of both fundic accommodation and antral contractility to supplement routine GES.

Clinical assessment of gastric emptying and sensory function utilizing gamma scintigraphy: Establishment of reference intervals for the liquid and solid components of the Nottingham test meal in healthy subjects

BACKGROUND

Current investigations of stomach function are based on small test meals that do not reliably induce symptoms and analysis techniques that rarely detect clinically relevant dysfunction. This study presents the reference intervals of the modular "Nottingham test meal" (NTM) for assessment of gastric function by gamma scintigraphy (GSc) in a representative population of healthy volunteers (HVs) stratified for age and sex.

METHODS

The NTM comprises 400 mL liquid nutrient (0.75 kcal/mL) and an optional solid component (12 solid agar-beads (0 kcal). Filling and dyspeptic sensations were documented by 100 mm visual analogue scale (VAS). Gamma scintigraphy parameters that describe early and late phase Gastric emptying (GE) were calculated from validated models.

KEY RESULTS

Gastric emptying (GE) of the liquid component was measured in 73 HVs (male 34; aged 45±20). The NTM produced normal postprandial fullness (VAS ≥30 in 41/74 subjects). Dyspeptic symptoms were rare (VAS ≥30 in 2/74 subjects). Gastric emptying half-time with the Liquid- and Solid-component -NTM was median 44 (95% reference interval 28-78) minutes and 162 (144-193) minutes, respectively. Gastric accommodation was assessed by the ratio of the liquid-NTM retained in the proximal:total stomach and by Early phase emptying assessed by gastric volume after completing the meal (GCV0). No consistent effect of anthropometric measures on GE parameters was present.

CONCLUSIONS AND INFERENCES

Reference intervals are presented for GSc measurements of gastric motor and sensory function assessed by the NTM. Studies involving patients are required to determine whether the reference interval range offers optimal diagnostic sensitivity and specificity.

Gastrointestinal motility dysfunction in critically ill patients: Pathogenesis, clinical assessment, and treatment

Gastrointestinal motility dysfunction is a common clinical complication in ICU patients, which can lead to difficulty in enteral nutrition, vomiting, diarrhea, increased intra-abdominal pressure, ventilator associated pneumonia, intestinal flora displacement, and other adverse reactions. The clinical features of gastrointestinal dysfunction mainly include gastric emptying disturbance, intestinal dysfunction, and gastrointestinal motility disorders. The causes of gastrointestinal motility dysfunction in ICU patients are complex and the clinical evaluation of gastrointestinal dysfunction is difficult. These factors have led to the fact that gastrointestinal motility monitoring techniques have not been widely used in clinical practice. Timely detection and correction of gastrointestinal motility dysfunction in ICU patients can improve outcomes. This article reviews the etiology, clinical evaluation, and treatment of gastrointestinal motility dysfunction in ICU patients.

Intragastric Meal Distribution During Gastric Emptying Scintigraphy for Assessment of Fundic Accommodation: Correlation with Symptoms of Gastroparesis

Impaired fundic accommodation (FA) limits fundic relaxation and the ability to act as a reservoir for food. Assessing intragastric meal distribution (IMD) during gastric emptying scintigraphy (GES) allows for a simple measure of FA. The 3 goals of this study were to evaluate trained readers' (nuclear medicine and radiology physicians) visual assessments of FA from solid-meal GES; develop software to quantify GES IMD; and correlate symptoms of gastroparesis with IMD and gastric emptying. Methods: After training to achieve a consensus interpretation of GES FA, 4 readers interpreted FA in 148 GES studies from normal volunteers and patients. Mixture distribution and κ-agreement analyses were used to assess reader consistency and agreement of scoring of FA. Semiautomated software was used to quantify IMD (ratio of gastric counts in the proximal stomach to those in the total stomach) at 0, 1, 2, 3, and 4 h after ingestion of a meal. Receiver-operating-characteristic analysis was performed to optimize the diagnosis of abnormal IMD at 0 min (IMD⁰) with impaired FA. IMD⁰, GES, water load testing, and symptoms were then compared in 177 patients with symptoms of gastroparesis. Results: Reader pairwise weighted κ-values for the visual assessment of FA averaged 0.43 (moderate agreement) for normal FA versus impaired FA. Readers achieved 84.0% consensus and 85.8% reproducibility in assessing impaired FA. IMD⁰ based on the division of the stomach into proximal and distal halves averaged 0.809 (SD, 0.083) for normal FA and 0.447 (SD, 0.132) (P < 0.01) for impaired FA. On the basis of receiver-operating-characteristic analysis, the optimal cutoff for IMD⁰ discrimination of normal FA from impaired FA was 0.568 (sensitivity, 86.7%; specificity, 91.7%). Of 177 patients with symptoms of gastroparesis, 129 (72.9%) had delayed gastric emptying; 25 (14.1%) had abnormal IMD⁰ Low IMD⁰ (impaired FA) was associated with increased early satiety (P = 0.02). Conclusion: FA can be assessed visually during routine GES with moderate agreement and high reader consistency. Visual and quantitative assessments of FA during GES can yield additional information on gastric motility to help explain patients' symptoms.

Prevalence of Gastric Motility Disorders in Patients with Functional Dyspepsia

Background/Aims

Gastric motility abnormalities have been considered to be pathophysiological features of functional dyspepsia (FD) that are closely related to dyspepsia symptoms, especially postprandial distress syndrome (PDS). The aims of this study are to (1) investigate the prevalence of gastric motility disorders and (2) evaluate the association between gastric motility abnormalities and dyspeptic symptoms using gastric scintigraphy in the PDS type of FD.

Methods

Forty healthy subjects and 94 PDS type FD patients were enrolled in the study. The volunteers and patients ingested a radiolabeled (technetium-99m) solid test meal, and scintigraphic images were recorded. Gastric accommodation and emptying were assessed by scintigraphic imaging. The patients’ dyspeptic symptoms were also explored using self-completed symptom questionnaires with 10 variables (4 scales, 0–3 points) at the same time.

Results

In 94 Japanese FD patients, the prevalence of impaired gastric accommodation and delayed emptying were 14.9% (14/94) and 10.6% (10/94), respectively. Gastric motility abnormalities were seen in 25.5% (24/94) of FD patients. There was no association between gastric motility abnormalities and dyspeptic symptoms.

Conclusions

Gastric motility abnormalities were seen in 25.5% of Japanese PDS type FD patients. However, there was no association between gastric motility abnormalities and dyspeptic symptoms on gastric scintigraphy.

A double-blind placebo controlled study of acotiamide hydrochloride for efficacy on gastrointestinal motility of patients with functional dyspepsia

BACKGROUND

Acotiamide is widely used to improve symptoms in patients with functional dyspepsia (FD) in multiple large-scale clinical studies, but there are few reports about the drug's mechanism of action. The aim of this study was to assess the effects of acotiamide on gastric accommodation and gastric emptying, gastrointestinal symptoms, and health-related quality of life (HR-QOL) in a placebo-controlled study.

METHODS

We conducted a randomized, double-blind placebo-controlled study. Fifty Japanese FD patients were randomly assigned to either placebo (n = 25) or acotiamide 100 mg × 3/day for 2 weeks (n = 25). At baseline and at 2 weeks of treatment, we evaluated the patients' gastric motility using scintigraphy to determine the accommodation and emptying values, gastrointestinal symptom rating scale (GSRS), HR-QOL (SF-8), and anxiety and depression scale (HADS).

RESULTS

Four patients failed to complete the medication regimen and were omitted from analysis; data from 24 placebo patients and 22 acotiamide patients were analyzed. Acotiamide significantly increased gastric accommodation compared to the placebo (p = 0.04 vs. p = 0.08; respectively). Acotiamide significantly accelerated gastric emptying (50 % half-emptying time) (p = 0.02 vs. p = 0.59). Acotiamide significantly improved the total GSRS scores compared to placebo (p = 0.0007 vs. p = 0.14). HR-QOL did not differ significantly between the two groups, but acotiamide significantly improved the HADS anxiety score compared to placebo (p = 0.04 vs. p = 0.20).

CONCLUSIONS

Our placebo-controlled study demonstrated that acotiamide significantly increased both gastric accommodation and gastric emptying in Japanese FD patients. Acotiamide also improved the patients' dyspeptic symptoms and anxiety score. Clinical Trials Registry no: UMIN000013544.

Assessment of Gastric Accommodation in Patients with Functional Dyspepsia by 99mTc-Pertechtenate Single Photon Emission Computed Tomography Imaging: Practical but not Widely Accepted

Objective:

Impaired gastric accommodation is one of the main symptoms in patients with functional dyspepsia. The aim of the present study was to assess gastric accommodation in patients with functional dyspepsia using single photon emission computed tomography (SPECT) imaging.

Methods:

Twenty-four patients with functional dyspepsia and 50 healthy volunteers as control group were enrolled in this study. All participants were given 5 mCi 99mTc-pertechtenate intravenously, served with a low fat meal, and underwent SPECT scanning 20 minutes after the meal.

Results:

Based on the scintigraphic data, gastric volumes were found to be significantly increased after food ingestion in both patient and control groups. We also found that while there was no significant difference between patient and control groups in terms of fasting gastric volumes, postprandial gastric volume was significantly lower in patients as compared to healthy individuals (p<0.05).

Conclusion:

Measuring gastric volume by using SPECT can be a valuable method in the detection of functional dyspepsia and in differentiation of this entity from other organic disorders.

Normal values and symptom correlation of a simplified oatmeal-based gastric emptying study in the Chinese population

BACKGROUND AND AIM

Instant oatmeal has been proposed as a good alternative to the standardized low-fat egg white test meal for gastric emptying studies. We aim to establish normal values of oatmeal-based gastric emptying scintigraphy and test its correlation with gastroparesis symptoms in the Chinese population.

METHODS

This study prospectively enrolled 60 healthy volunteers, 30 functional dyspepsia and 30 diabetes patients with gastroparesis symptoms. All participants were evaluated using the Gastroparesis Cardinal Symptom Index. Each participant ingested instant oatmeal mixed with 1 mCi of (99m) Tc diethylenetriaminepentacetic acid, and serial imaging was immediately acquired for 3 h in the supine position using a left anterior oblique projection. Time-activity curves were generated and quantitative parameters were determined. Normal values were established from healthy volunteers and further applied in the symptomatic patients.

RESULTS

All participants finished the test meal and tolerated the procedure well. All gastric emptying parameters were not significantly affected by age or gender. Values above the 95th percentile of T1/2 , gastric retention at 1, 2, and 3 h (85 min, 65%, 28%, and 8%, respectively) were indicative of delayed gastric emptying. Values below the 5th percentile of gastric retention at 0.5 and 1 h (40% and 15%, respectively) were indicative of rapid gastric emptying. The lower gastric retention limit at 0.5 and 1 h were 40% and 15%, respectively. Four (13.3%) diabetes and four (13.3%) functional dyspepsia patients had delayed emptying while three diabetes patients (10%) had rapid emptying. Gastric emptying parameters correlated best with vomiting (r = 0.621) and nausea (r = 0.566) in diabetes patients.

CONCLUSIONS

We established normal values of oatmeal-based gastric emptying scintigraphy and observed good correlation with cardinal gastroparesis symptoms in the Chinese population.

DA-9701: A New Multi-Acting Drug for the Treatment of Functional Dyspepsia

Motilitone^® (DA-9701) is a new herbal drug that was launched for the treatment of functional dyspepsia in December 2011 in Korea. The heterogeneous symptom pattern and multiple causes of functional dyspepsia have resulted in multiple drug target strategies for its treatment. DA-9701, a compound consisting of a combination of Corydalis Tuber and Pharbitidis Semen, has being developed for treatment of functional dyspepsia. It has multiple mechanisms of action such as fundus relaxation, visceral analgesia, and prokinetic effects. Furthermore, it was found to significantly enhance meal-induced gastric accommodation and increase gastric compliance in dogs. DA-9701 also showed an analgesic effect in rats with colorectal distension induced visceral hypersensitivity and an antinociceptive effect in beagle dogs with gastric distension-induced nociception. The pharmacological effects of DA-9701 also include conventional effects, such as enhanced gastric emptying and gastrointestinal transit. The safety profi le of DA-9701 is also preferable to that of other treatments.