On the validity of the ¹³C‐acetate breath test for comparing gastric emptying of different liquid test meals: a validation study using magnetic resonance imaging

Abstract

Background 13C‐acetate breath testing (BT) is applied to assess and compare gastric emptying of liquid meals. Gastric half‐emptying times (t50) from BT show offsets compared to t50 values from γ‐scintigraphy and ultrasonography. Linear transformations have been proposed to correct these offsets. This investigation critically validates the BT for the assessment of liquid gastric emptying by using simultaneously recorded meal and total gastric content volume emptying data from magnetic resonance imaging (MRI). Methods Data were collected during a recently published double‐blind, randomized, cross‐over MRI gastric emptying study of three 13C‐labeled enteral formulas differing in protein sources (PMID: 24699556). Breath testing‐derived t50 was computed with the analysis methods commonly applied in gastric emptying research, i.e., the exponential‐beta function and the Wagner–Nelson (WN) method, respectively. Key Results Breath testing t50 values from exponential‐beta function and WN method showed a positive and negative offset to MRI data, respectively. Linear regression detected low concordance between MRI and both BT methods revealing meal specific and emptying rate‐dependent offsets. The WN method showed worse agreement and correlation with MRI emptying data. Breath testing rather reflected meal volume than total gastric content volume emptying. Conclusions & Inferences This validation study indicates that the 13C‐acetate breath test may not be applied to compare gastric emptying of arbitrary liquid meals without prior validation by imaging methods. t50 values from BT are biased by (i) the properties of the meal and (ii) the selected method used for 13CO2 exhalation analysis. No linear transformation common for all meals was applicable to correct the offsets between BT and MRI.

Gender Difference of Gastric Emptying in Healthy Volunteers and Patients with Functional Dyspepsia

“…Delayed gastric emptying is one of the causes of FD. Gastric emptying can be measured by several kinds of methods, such as gastric emptying scintigraphy, barium-sandwich emptying radiography, gastric emptying ultrasound and 13 C-acetate breath test [5,6,7]. The 13 C-acetate breath test is widely used for the indirect assessment of gastric emptying [5].…”

“…Gastric emptying can be measured by several kinds of methods, such as gastric emptying scintigraphy, barium-sandwich emptying radiography, gastric emptying ultrasound and 13 C-acetate breath test [5,6,7]. The 13 C-acetate breath test is widely used for the indirect assessment of gastric emptying [5]. The advantage of 13 C-acetate breath test is that it is a simple and easy method, there is no exposure to radiation, and there is no need for specialized facilities [8].…”

Indirect vs direct assessment of gastric emptying: A randomized crossover trial comparing C‐isotope breath analysis and MRI

“…The current study assessed GE over 90 minutes with both BT and MRI, whereas other studies kept collecting breath samples after finishing the MRI measurements . Our MRI measurements showed that at the end of the sampling time not all of the meal had emptied from the stomach.…”

“…This was measured by MRI and BT using 100 mg 13 C‐acetate. It was suggested that these differences were caused by dilution by gastric secretions and the composition of the meal . Accordingly, tracer interactions with fat components in a test meal have been shown to affect tracer absorption and subsequent excretion and thus tracer‐based estimates of GE.…”

“…Longer sample collection duration may increase accuracy but this may not always be necessary. With liquid foods, recovery differences are apparent within 2 hours post ingestion . Apparently, liquid meals empty relatively quickly, especially if their macronutrient content is low .…”