Indirect vs direct assessment of gastric emptying: A randomized crossover trial comparing C-isotope breath analysis and MRI
Neurogastroenterology and Motility
Gastric emptying (GE) is an important element of gastrointestinal physiology. For clinical applications, highly accurate measurements of GE on an individual level are required for diagnosis. 1 In a research setting GE measurements are often used to determine group differences in GE between treatments (for example. 2, 3 Gastric emptying can be measured directly or indirectly. Direct methods include echography, scintigraphy, and MRI. 4 MRI has been validated as an accurate method to measure GE 5
... od to measure GE 5 ; it allows accurate real-time visualization and determination of gastric content without Abstract Background: Indirect methods to assess gastric emptying (GE), such as 13 C breath tests (BT), are commonly used. However, BT usually use a sampling time of 4+ hours. The current study aims to assess the validity of BT for four liquid meals differing in physicochemical properties. To this aim, we compared them to MRI GE-measurements. Methods: Fifteen healthy males (age 22.6 ± 2.4 years, BMI 22.6 ± 1.8 kg/m 2 ) participated in a randomized 2 × 2 crossover experiment. Test foods were liquid meals, which were either thin/thick and 100/500 kcal, labeled with 100 mg of 13 C-octanoate. GE was measured with MRI and assessed by 13 C recovery from breath. Participants were scanned every 10 minutes and at six time points breath samples were collected up to t = 90 minutes. Two curves were fitted to the data to estimate emptying halftime (t 50 Ghoos and t 50 Bluck ). T 50 times were ranked per participant and compared between methods. Key Results: On average, MRI and BT showed similar t 50 rankings for the four liquid meals. In comparison to MRI, t 50 Ghoos overestimated, while t 50 Bluck underestimated GE time . Moreover, more viscous foods were overestimated. In most participants individual t 50 time rankings differed significantly between methods. Conclusions & Inferences: BT can assess relative emptying differences on group level and collecting breath data for 90 minutes constitutes a lower burden for participants and the research facility. However, BT has severe shortcomings compared to MRI for individual GE assessment. Notably, food matrix effects should be considered when interpreting the results of BT. K E Y W O R D S breath, gastric emptying, isotope, MRI This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.