Novel and Validated Approaches for Gastric Emptying Scintigraphy in Patients with Suspected Gastroparesis

Abstract

Controversy exists regarding the relation of upper gastrointestinal symptoms to gastroparesis, which centers on the reportedly weak correlation between symptoms and gastric emptying (GE) measurements. Appropriate management of patients with suspected gastroparesis thus requires the use of validated assessments of GE.GE scintigraphy (GES) using a low-fat EggBeaters (chicken egg white) meal (ConAgra Foods Inc., Omaha, NE, USA) [1] is regarded as the gold standard due to standardized procedures, methods, and well-established normal values. Although this meal has the advantage of good tolerability by the majority of symptomatic patients, there are potential drawbacks: a few patients may not tolerate any solid meal, or the low fat and caloric content may not be able to adequately stress the system, failing to identify impaired gastric motor function in a subset of individuals. Therefore, identification of an alternative, appropriate test meal may be important for clinical and research applications.In this issue, Sachdeva et al.[2] compared GE of the low-fat EggBeaters solid meal (255 kcal containing 2 % fat, 24 % protein, 72 % carbohydrate, and 2 % fiber) to an Ensure Plus (Abbott Laboratories, North Chicago, IL, USA) liquid meal (350 kcal containing 28 % fat, 15 % protein, 57 % carbohydrate, and no fiber) to identify a valid alternative for patients unable to consume the standard low-fat egg-white meal. On separate days, 20 healthy volunteers participated in a well-designed prospective study comparing GES with these two meals; simultaneously, the authors evaluated gastric contractility using a wireless motility capsule (WMC) during both assessments.The objectives were to demonstrate feasibility and to provide hypothesis-generating data (e.g., definition of coefficient of variation [COV; standard deviation/mean] to facilitate the design of future studies).The conclusion that GE of a liquid nutrient meal is similar to that of low-fat egg-white meal (of similar calorie content) is valid, at least in healthy subjects. Nevertheless, as acknowledged by the authors, their results will require replication in a larger cohort, and in subjects with suspected gastroparesis who might differ from a healthy population in terms of having differential GE of solid versus liquid meals. Jones et al. [3] previously reported a significant but weak (r = 0.42, p \ 0.01) correlation between GE of solids and nutrient-containing liquids among 86 patients with diabetes mellitus. In the study by Sachdeva et al. [2], the correlation between the GE T 1/2 of the two meals was similarly weak (r = 0.53) among healthy subjects, suggesting that there are significant intraindividual differences in the emptying of the two meals, and that less than 30 % of the variance is attributable to the same mechanisms for emptying of the two types of meals.It is also necessary to clarify the inter-individual COV with the EggBeaters and the liquid nutrient meal. Diagnostic interpretation of GE T 1/2 by GES in an individual patient requires robust definition of the i...

Gastric Emptying in the Elderly

“…Scintigraphy remains the gold standard for measurement of gastric emptying, and the use of dual isotopes allows both the solid and liquid components of a meal to be 24,25 Regional meal distribution can also be evaluated by defining regions of interest within the stomach. 5 Scintigraphy necessitates access to a gamma camera and is associated with radiation exposure and is, therefore, contraindicated in pregnancy and relatively contraindicated in children.…”

“…Despite the long-term adoption of scintigraphy as a diagnostic tool, there remains a lack of standardization of the technique (eg, meal composition and volume, posture of subjects, frequency and duration of data acquisition, and parameters used to quantify gastric emptying). 26 Breath tests represent an alternative approach, particularly when scintigraphy is not feasible, 2,24,26 and are based on the incorporation of Carbon-13-labeled substrates, usually Carbon-13-octanoic acid, into solid meals or nutrient liquid. The stable Carbon-13-isotope is emptied from the stomach and transported to the liver via the portal vein, where it is oxidized to 13 CO 2 .…”

“…The technique is operator dependent and more difficult in obesity. [24][25][26] High-resolution manometry is used predominantly for research purposes to record the frequency, amplitude, and organization of lumen-occlusive contractions in the antrum, pylorus, and duodenum using a multilumen catheter with an array of side holes and/or a pyloric sleeve sensor. 30 Proximal gastric relaxation in response to a meal can be evaluated in a laboratory using an electronic barostat; the volume of air required to maintain a fixed pressure in an intragastric bag is used as an index of proximal gastric tone.…”

Novel Diet, Drugs, and Gastric Interventions for Gastroparesis

“…This is well illustrated by the emptying profiles of different meals in Figure 1. 2 In general, liquids of low caloric density empty under the pressure gradient between fundic tone and pylorus and little motor action of the distal stomach, and liquids empty exponentially from the stomach. Higher caloric liquids or homogenized solids empty almost linearly under the pressure gradient from the fundus and coordinated antropyloroduodenal motility.…”

Functional Dyspepsia and Gastroparesis

“…There are several important principles: first, the nature and calorie content of the meal determine the rate of emptying [16]; second, whatever method is used, it should be characterized by robust normal data and performance characteristics [17,18]; third, the gastric emptying breath test (GEBT) requires accurate and validated methods for deriving gastric emptying parameters from 13 CO 2 enrichment [19]; fourth, both delayed and accelerated gastric emptying (fig. 1) may be associated with the same upper gastrointestinal symptoms such as fullness, nausea and bloating [20,21].…”