Glucagonlike Peptide-1 Receptor Agonists: The Good, the Bad, and the Ugly-Benefits for Glucose Control and Weight Loss with Side Effects of Delaying Gastric Emptying.

Glucagonlike peptide-1 (GLP-1) receptor agonists (RAs) are being increasingly used for glycemic control in patients with diabetes and for weight loss and weight management in obese subjects. There has been recent public awareness of the potential of GLP-1 RAs to delay gastric emptying and cause gastroparesis. By delaying gastric emptying, these agents can complicate the clinical evaluation of patients on these drugs by affecting diagnostic testing for gastroparesis. This article discusses GLP-1 RAs and their effects on gastric emptying, gastric food retention, and gastroparesis. This article highlights how physicians should be attuned to the gastric side effects of these popular therapeutic agents for blood glucose control in people with diabetes and for weight loss and weight management in obese patients.

Fourier Phase Analysis of Dynamic Antral Contraction Scintigraphy: New Software, Reference Values, and Comparisons to Conventional Gastric Emptying.

Dynamic antral contraction scintigraphy (DACS) has been used to evaluate for gastric dysmotility by measuring antral contraction frequency and ejection fraction (EF). Fourier phase image analysis has the potential to assess gastric antral contractions for dyssynchrony as has been used for analyzing nuclear cardiology ventriculography (multigated acquisition studies) for cardiac dyssynchrony. The aims of this study were to determine whether Fourier phase analysis helps to characterize antral motility physiology, whether Fourier phase analysis correlates with conventional gastric emptying scintigraphy (GES), and which DACS parameters may aid in diagnosing gastric dysmotility, particularly delayed gastric emptying (GE). Methods: DACS and GES of healthy volunteers (n = 22) were compared with patients (n = 99) with symptoms of gastroparesis. New DACS Fourier phase analysis software was developed. Results: GE was delayed (n = 53) or normal (n = 46) in patients. There was a linear correlation between the time for the stomach to empty 50% of the meal and the percentage total proximal and distal in-phase antral pixels at 30 min (r = 0.37, P = 0.0001) and 60 min (r = 0.26, P = 0.007). In healthy volunteers, the mean proximal-to-distal ratio of in-phase antral pixels increased from 1.67 (30 min) to 2.65 (120 min) (P = 0.035), and EF increased from 23% (30 min) to 32% (120 min) (P = 0.022). Multivariable regressions of percentage total proximal and distal in-phase antral pixels (30 min) and EF (60 min) were the best predictors of abnormal GE (adjusted odds ratio, 3.30 [95% CI, 1.21-9.00] and 2.97 [95% CI, 1.08-8.21], respectively). Conclusion: This study used Fourier phase analysis to analyze DACS in healthy volunteers and patients with symptoms of gastroparesis. In addition to establishing reference values, new physiologic information on antral motility was obtained. In healthy volunteers, there was an increasing proximal-to-distal ratio of in-phase antral pixels and antral EF over time after meal ingestion. The percentage total proximal and distal in-phase antral pixels at both 30 and 60 min correlated well with GE values for the time for the stomach to empty 50% of the meal. For symptomatic patients, the percentage total proximal and distal in-phase antral pixels at 30 min and the EF at 60 min after meal ingestion correlated with delayed GE on conventional GES. Thus, Fourier phase analysis of DACS appears to have potential to further aid in diagnosing gastric dysmotility in GES.

Relationships among intragastric meal distribution during gastric emptying scintigraphy, water consumption during water load satiety testing, and symptoms of gastroparesis.

Gastric emptying scintigraphy (GES) measures total gastric retention after a solid meal and can assess intragastric meal distribution (IMD). Water load satiety test (WLST) measures gastric capacity. Both IMD immediately after meal ingestion [ratio of proximal gastric counts after meal ingestion to total gastric counts at time 0 (IMD0)] and WLST (volume of water ingested over 5 min) are indirect measures of gastric accommodation. In this study, IMD0 and WLST were compared with each other and to symptoms of gastroparesis to gauge their clinical utility for assessing patients with symptoms of gastroparesis. Patients with symptoms of gastroparesis underwent GES to obtain gastric retention and IMD0, WLST, and filled out patient assessment of upper GI symptoms. A total of 234 patients with symptoms of gastroparesis were assessed (86 patients with diabetes, 130 idiopathic, 18 postfundoplication) and 175 (75%) delayed gastric emptying. Low IMD0 <0.568 suggesting initial rapid transit to the distal stomach was present in 8% and correlated with lower gastric retention, less heartburn, and lower volumes consumed during WLST. Low WLST volume (<238 mL) was present in 20% and associated with increased severity of early satiety, postprandial fullness, loss of appetite, and nausea. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. Thus, IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.NEW & NOTEWORTHY IMD0 and WLST were assessed for their clinical utility in assessing patients with symptoms of gastroparesis. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.

Buspirone for early satiety and symptoms of gastroparesis: A multi-centre, randomised, placebo-controlled, double-masked trial (BESST).

BACKGROUND: Patients with gastroparesis and related disorders have symptoms including early satiety, postprandial fullness and bloating. Buspirone, a 5-HT1 receptor agonist, may improve fundic accommodation. AIM: To determine if buspirone treatment improves early satiety and postprandial fullness in patients with symptoms of gastroparesis. METHODS: This 4-week multi-centre clinical trial randomised patients with symptoms of gastroparesis and moderate-to-severe symptoms of fullness (Gastroparesis Cardinal Symptom Index [GCSI] early satiety/postprandial fullness subscore [ES/PPF]) to buspirone (10 mg orally) or placebo three times per day. The primary outcome was a change in the ES/PPF from baseline to 4 weeks. The primary analysis was per protocol intention-to-treat ANCOVA of between-group baseline vs. 4-week differences (DoD) in ES/PPF adjusted for baseline ES/PPF. Results are reported using both nominal and Bonferroni (BF) p values. RESULTS AND CONCLUSIONS: Ninety-six patients (47 buspirone, 49 placeboes; 92% female, 50% delayed gastric emptying, 39% diabetic) were enrolled. There was no between-groups difference in the 4-week ES/PPF primary outcome: -1.16 ± 1.25 (SD) on buspirone vs -1.03 ± 1.29 (SD) on placebo (mean DoD: -0.11 [95% CI: -0.68, 0.45]; p = 0.69). Buspirone performed better than placebo in patients with severe-to-very severe bloating at baseline compared to patients with none to moderate: (ES/PPF DoD = -0.65 vs. 1.58, pTX*GROUP  = 0.003; pBF  = 0.07). Among individual GCSI symptoms, only bloating appeared to improve with buspirone vs. placebo. CONCLUSIONS: Patients with moderate-to-severe early satiety/postprandial fullness and other symptoms of gastroparesis did not benefit from buspirone treatment to improve the ES/PPF primary outcome compared with placebo. There was a suggestion of the benefit of buspirone in patients with more severe bloating. TRIAL REGISTRATION: ClinicalTrials.gov NCT0358714285.

Proximal and distal intragastric meal distribution during gastric emptying scintigraphy: Relationships to symptoms of gastroparesis.

BACKGROUND: Total gastric retention (TGR) from gastric emptying scintigraphy (GES) is used for diagnosing gastroparesis (Gp), but correlates poorly with patients' symptoms. Regional intragastric meal distribution (RIMD) can also be assessed from GES. This study classified patients' meal distribution as proximal or distal to relate RIMD to symptoms of Gp. METHODS: GES studies in patients (n = 193) and control subjects (n = 21) were selected for RIMD analysis. Patients completed Patient Assessment of Upper Gastrointestinal Symptoms (PAGI-SYM) for symptom severity before GES. TGR was analyzed using % TGR, and RIMD used a proximal/distal gastric count ratio (PDCR). Results were classified as proximal or distal RIMD at 0, 1, 2, and 4 h postprandially based on their PDCR being above or below the median value of the patients. RESULTS: Patients with delayed GE and immediate post-meal ingestion distal distribution had more severe early satiety and regurgitation. Distal distribution at 1 h had more severe early satiety and loss of appetite compared to proximal distribution. Patients with delayed GE and proximal distribution at 4 h had more severe nausea, retching, and vomiting compared to 4 h distal distribution. Severely delayed 4 h proximal distribution had more nausea than severely delayed 4 h distal distribution. CONCLUSIONS: Increased early distal IMD in patients with delayed GE was associated with regurgitation and early satiety whereas increased late proximal IMD was associated with nausea, retching, and vomiting. Differentiating proximal from distal meal distribution patterns helps to relate symptoms to gastric dysfunction and may be helpful for directing therapy.

Postprandial symptoms in patients with symptoms of gastroparesis: roles of gastric emptying and accommodation.

Patients often are evaluated for gastroparesis because of symptoms occurring with meals. Gastric emptying scintigraphy (GES) is used for gastroparesis diagnosis, although results are not well correlated with gastroparesis symptoms. The aim of this study is to assess relationships between gastroparesis symptoms, gastric emptying (GE), and gastric accommodation (GA). Patients with symptoms of gastroparesis completed the Patient Assessment of Upper GI Symptoms (PAGI-SYM) and recorded symptoms during GES and water load satiety test (WLST), an indirect assessment for GA. A total of 109 patients with gastroparesis symptoms were assessed. Symptom severity increased after GES meal for stomach fullness, belching, nausea, abdominal burning, and abdominal pain. There was no difference in symptoms after meal between patients with delayed (n = 66) and normal (n = 42) GE. Diabetic patients (n = 26) had greater gastric retention than idiopathic patients (n = 78), but idiopathic patients had greater postprandial nausea, stomach fullness, and abdominal pain. Water consumed during WLST averaged 421 ± 245 mL. Idiopathic patients had greater nausea scores during WLST than diabetic patients. In comparison to those with normal water consumption (≥238 mL; n = 80), patients with impaired water ingestion (<238 mL; n = 26) had increased stomach fullness, early satiety, postprandial fullness, and loss of appetite on PAGI-SYM. Patients with delayed and normal GE had similar symptom profiles during GES and WLST. Idiopathic patients had less gastric retention but more symptoms after GES meal and after WLST compared with diabetic patients. Patients with impaired water consumption during WLST had increased symptoms by PAGI-SYM. These data suggest that impaired GA, rather than GE, may be important in explaining postprandial symptoms in patients with symptoms of gastroparesis.NEW & NOTEWORTHY Patients with delayed and normal gastric emptying (GE) had similar symptom profiles during gastric emptying scintigraphy (GES). Idiopathic patients with symptoms of gastroparesis had less gastric retention by GES; but more symptoms after GES meal and after water load satiety test (WLST) compared with diabetic patients. In patients with symptoms of gastroparesis, symptoms after WLST increased with decreasing water consumption. Early satiety and loss of appetite were associated with decreased water consumption during WLST. Thus, impaired accommodation and perhaps visceral hypersensitivity are important in explaining postprandial symptoms in gastroparesis.

Gastric half emptying time (T½ ) for 4-h gastric emptying scintigraphy simplifies reporting but reduces detection of gastroparesis.

BACKGROUND: Gastric emptying scintigraphy (GES) reports percent retention at 1, 2, and 4 h. Time to empty half the meal (T½ ) could simplify GE reporting. AIMS: To compare the performance of GES T½ to 1-, 2-, and 4-h retention. METHODS: GES studies were reviewed; results determined according to retention at 1, 2, and 4 h. T½ was determined using 3 methods: (1) GES curve fitting using 0, 0.5, 1, 2, 3, and 4 h data; (2) linear interpolation using 0, 0.5, 1, 2, 3, and 4 h data; and (3) linear interpolation using only 0, 1, 2, and 4 h data. RESULTS: Of 495 patients, 265 had normal GE, 4 rapid GE (<30% retention at 1 h), and 226 delayed GE: 17 delayed only at 2 h (>60% ret); 94 delayed only at 4 h (>10% ret); and 115 delayed at both 2 h and 4 h. Strong correlations were seen between each T½ method and 1, 2, 3, and 4 h %-empty values: curve-fit T½ (r = -0.851, -0.942, -0.864, -0.744), linear T½ using all imaging times (r = -0.848, -0.972, -0.878, -0.763), and linear T½ using standard imaging times (r = -0.853, -0.974, -0.868, -0.760). The 132 min cutoff for delayed GE captures 99.1% to 100% of delayed GE at both 2 h and 4 h, 76.5% to 94.1% delayed at 2 h only, but only 36.7% to 39.4% delayed at 4 h only; 3.5 to 11.3% of patients with normal GE miscategorized as delayed. CONCLUSIONS: GES T½ correlates more strongly with retention at 2 h than at 4 h. T½ alone may misclassify patients, particularly those with late-phase (4 h only) delays, reducing its utility for diagnosing gastroparesis.

The Utility of Adding a Liquid-Nutrient Meal to Aid Interpretation of Small-Bowel Transit Scintigraphy.

Small-bowel transit scintigraphy (SBTS) evaluates the accumulation of a radiolabeled meal in the terminal ileal reservoir (TIR) 6 h after ingestion. The location of the TIR may be difficult to determine because anatomic information is limited; for equivocal studies, the patient is asked to return the next day to help determine the TIR location by potential transit into the colon. The purpose of this study was to evaluate whether administration of an additional liquid-nutrient meal (LNM) at 6 h can promote movement of the radiolabeled meal to aid in the interpretation of SBTS and eliminate the need for the patient to return. Methods: This retrospective study reviewed 117 SBTS studies from February 2017 to September 2019. Patients were fed a standardized mixed radiolabeled solid-liquid meal for gastric emptying with SBTS according to Society of Nuclear Medicine and Molecular Imaging practice guidelines. An additional LNM was given at 6 h, and post-LNM images were obtained at least 20 min after the LNM. Two board-certified nuclear medicine physicians independently evaluated all images as equivocal or diagnostic at 6 h. Results: Of the 117 patients (71.8% female; median age, 42.0 y) undergoing SBTS, 37 were equivocal cases at 6 h before the LNM (31.6%; 95% CI, 23.3%-40.9%), compared with 12 equivocal cases after the LNM (10.3%; 95% CI, 5.4%-17.2%). Of the equivocal cases, 25 (69.4%; 95% CI, 51.9%-83.7%) had a definitive result after the LNM, whereas 11 (30.6%; 95% CI, 16.4%-48.1%) remained equivocal and 1 showed rapid transit. Among the 23 patients with gastroparesis, only 13 (57%) responded to the LNM, and none of the 3 patients with irritable bowel syndrome responded. Conclusion: The number of equivocal SBTS cases decreased after administration of an LNM at 6 h, converting to a definitive result. This suggests that with use of an LNM, most patients can complete SBTS in 1 d without the need for repeat imaging at 24 h. Administering an LNM appears to be less effective for patients with gastric disorders. However, the clinical significance remains to be explored, and it is unclear whether such patients have both a gastric and a small-bowel disorder, hence reducing any motility-promoting effect of the LNM.

Addition of small-bowel transit scintigraphy to gastric emptying for assessment of patients with upper gastrointestinal symptoms.

BACKGROUND: Dyspeptic symptoms are not well correlated with gastric emptying (GE) results. AIMS: To determine (a) prevalence of delayed SB transit (SBT) in patients undergoing GE scintigraphy for symptoms of gastroparesis; (b) symptoms associated with delayed SBT. METHODS: Patients with symptoms of gastroparesis underwent combined GE and SBT scintigraphy (GES/SBTS). Patients ingested a mixed solid (S)-liquid (L) meal with egg whites labeled with 500 µCi Tc-99 m sulfur colloid and water with 125 µCi In-111 DTPA. Retained S and L gastric activity and percent of L In-111 activity in terminal ileum (TI) and/or cecum/colon at 6 h were determined. Patient Assessment of Gastrointestinal Symptoms (PAGI-SYM) assessed symptoms from 0 (none) to 5 (very severe). KEY RESULTS: Of 363 patients, 174 (47.9%) had delayed S GE, 141 (38.8%) delayed L GE, and 70 (19.3%) delayed SBT. Delayed SBT was seen in 24 (6.6%) with normal S GE and 46 (12.7%) with delayed S GE. Patients with isolated delayed SBT had highest symptom scores for postprandial fullness (3.5), stomach fullness (3.4), nausea (3.2), bloating (3.2), compared to isolated delayed S GE who had highest symptom scores for postprandial fullness (3.7), nausea (3.6), stomach fullness (3.4), and early satiety (3.3). CONCLUSIONS & INFERENCES: Delayed SBT occurred in 19.3% of dyspeptic patients using GES/SBTS. While postprandial and stomach fullness were common to both delayed S GE and delayed SBT, early satiety was associated with delayed S GE whereas bloating was associated with delayed SBT. Thus, SBTS can augment GES to help explain some symptoms associated with dyspepsia and suspected gastroparesis.

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.

The effects of ulimorelin, a ghrelin agonist, on liquid gastric emptying and colonic transit in humans.

BACKGROUND: Ulimorelin, a small molecule ghrelin agonist and prokinetic agent, was effective in animal models of gastroparesis and delayed transit. However, employing once daily administration, it failed in clinical trials of postoperative ileus (POI), a condition in which colonic motility recovers last. The aim of this study was to evaluate drug dosing and regional differences in drug activity between stomach and colon. METHODS: Gastric emptying was assessed by scintigraphy in healthy adults at single doses of 600-1200 µg kg-1 and multiple doses of 80-600 µg kg-1 Q8H for 7 days. Colonic motility was assessed by 7-region scintigraphic analysis at a dose of 600 µg kg-1 for 2 days. The primary endpoints were percent change in time to 50% (∆t50 ) liquid gastric emptying on Days 1, 4, and 6 and the geometric mean center of colonic transit at 24 hours (GC24 ). Plasma concentrations of free and total ulimorelin were measured for pharmacokinetic and exposure-response modeling. KEY RESULTS: Ulimorelin 150-600 µg kg-1 every 8 hours resulted in statistically significant improvements (∆t50  = 23% to 46% (P < .05)) in gastric emptying from baseline that were sustained through Day 6. However, no effects on GC24 were observed. Pharmacokinetic analyses suggested that the free concentrations of ulimorelin achieved in POI trials and dosing frequency may have been inadequate. CONCLUSIONS AND INFERENCES: Ulimorelin is a potent gastric prokinetic but lacks evidence of activity in the human colon, pointing to the stomach as the predominant site of action of ghrelin in humans; ClinicalTrials.gov NCT02993055.

Using gastric emptying scintigraphy to evaluate antral contractions and duodenal bolus propagation.

Our aim was to investigate the feasibility of measuring antral contractions and duodenal bolus propagation (DBP) during dynamic antral contraction scintigraphy (DACS) as an assessment of antro-pyloro-duodenal coordination (APDC). Gastric emptying scintigraphy (GES) with DACS was performed with Tc-99m sulfur colloid (SC) using increasing doses of 74 MBq (2 mCi) for 10 subjects, 185 MBq (5 mCi) for 11, and 370 MBq (10 mCi) for 11. DACS was performed for 10 min after static images at 0, 30, 60, 120, 180, and 240 min in anterior and right anterior oblique (RAO) projections. Best projection and lowest dose of Tc-99m SC were assessed visually. DBP were quantified utilizing duodenal activity peaks from a region of interest in the first portion of the duodenum. DBP was better visualized in the RAO projection than anterior projection and using 185 MBq (5 mCi) and 370 MBq (10 mCi) compared with 74 MBq (2 mCi). DBP showed infrequent and irregular bolus transfers from the antrum to the duodenum. Antral activity peaks at 60 min averaged 2.91 ± 0.66 per minute and duodenum bolus peaks 0.36 ± 0.18 per minute (ratio 0.36/2.91 = 0.12). DBP activity peaks can be measured during GES with DACS but requires a 185-MBq (5 mCi) dose of Tc-99m SC radiolabeled test meal for adequate DBP signal detection and is better imaged in RAO than anterior projection. DBPs over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess APDC.NEW & NOTEWORTHY This study shows that duodenal bolus propagations after meal ingestion can be measured during gastric emptying scintigraphy using dynamic scintigraphy. Duodenal bolus propagation over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess antropyloroduodenal coordination in patients with unexplained symptoms of upper gastrointestinal dysmotility.

Update on Serum Glucose and Metabolic Management of Clinical Nuclear Medicine Studies: Current Status and Proposed Future Directions.

Management of a patient's blood glucose or metabolism in nuclear medicine studies has become an integral aspect of daily work primarily due to the increasing use of F-18 flurodeoxyglucose (FDG) positron emission tomography (PET). Newer tracers such as F-18 Fluciclovine and C-11 Choline, are in theory subject to metabolic shifts and changes based on patients' insulin levels, and also require attention to achieving optimum patient preparation. Metabolic derangements can also affect other studies, such as gastric emptying (GE), the results of which are dependent upon the patient's blood glucose level during the time of imaging. The growing variety of diabetic medications has increased the complexity of the instructions which need to be given to patients. Current guidelines for patient preparation were developed in the past and have only slowly evolved with the introduction of newer oral medications. In addition to older insulin formulations newer formulations with different profiles of onset, duration, and consistency of action are being used. The wide spectrum of newer drugs now in use for treating diabetes has not been accompanied by any updated consensus on how to manage these drugs for imaging studies which require blood glucose level management. In this article we review these newer diabetes medications primarily to raise awareness of the changing landscape. Our focus will be on suggestions to optimize patient preparation and management for these studies. For each scenario, our suggestions will be given as summary proposals for best patient management. Our hope is that this discussion will stimulate multicenter studies to provide data to support new practice guidelines for metabolically dependent nuclear medicine procedures.

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.

Towards a Fuller Assessment of Gastric Motility in Patients With Upper GI Dyspepsia: Time to Accommodate!

There is increasing recognition of the importance of assessing patients with unexplained upper gastrointestinal symptoms for impaired gastric accommodation. New therapeutic approaches to treat impaired accommodation are being developed. This increasing interest in diagnosing and treating impaired gastric accommodation emphasizes the need to have a clinically available method to measure the gastric accommodation response. In this editorial, gastric accommodation is discussed along with the currently available methods for its assessment. We summarize our thoughts on what are the next steps needed to make a readily accessible method for assessing gastric accommodation more widely available.

The BEIR VII Estimates of Low-Dose Radiation Health Risks Are Based on Faulty Assumptions and Data Analyses: A Call for Reassessment.

The 2006 National Academy of Sciences Biologic Effects of Ionizing Radiation (BEIR) VII report is a well-recognized and frequently cited source on the legitimacy of the linear no-threshold (LNT) model-a model entailing a linear and causal relationship between ionizing radiation and human cancer risk. Linearity means that all radiation causes cancer and explicitly excludes a threshold below which radiogenic cancer risk disappears. However, the BEIR VII committee has erred in the interpretation of its selected literature; specifically, the in vitro data quoted fail to support LNT. Moreover, in vitro data cannot be considered as definitive proof of cancer development in intact organisms. This review is presented to stimulate a critical reevaluation by a BEIR VIII committee to reassess the validity, and use, of LNT and its derived policies.

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.