Gastric Accommodation Testing Using Hybrid Nuclear Imaging Volumetry and Combined High-Resolution Manometry-Nutrient...

Gastric accommodation (GA) testing is gaining clinical recognition as novel and minimally invasive modalities emerge. We investigated the feasibility of hybrid nuclear imaging volumetry (SPECT/CT) and combined high-resolution manometry-nutrient drink test (HRM-NDT) to assess GA.

In this non-randomized pilot study, [^99mTc]NaTcO₄ gastric SPECT/CT (250 mL protocol) and proximal gastric HRM-NDT (~60 mL/min protocol) were performed separately within 30 days using Ensure Gold test meal (1.05 kcal/mL; Abbott). GA parameters were measured, and their preliminary associations were examined using Spearman's ρ and Hoeffding's D correlation tests. Data were presented as median ± normalized median absolute deviation.

Twenty healthy, asymptomatic individuals (11 females; 23.5 ± 2.2 years, 23.7 ± 2.2 kg/m²) completed both procedures without serious adverse events and interrupted sessions. The accommodation volume and postprandial-to-fasting volume ratio from SPECT/CT were 325.8 ± 28.5 mL and 5.31 ± 1.28, respectively. During HRM-NDT, the nadir-intragastric pressure (IGP) was -6.6 ± 3.6 mmHg at an ingested volume of 360.0 ± 177.9 mL, and the area-under-curve of IGP was -1566.0 ± 1596.8 mmHg·mL. The maximum tolerated volume for reaching satiety/maximum discomfort was 450.0 ± 177.9 mL, and the area-under-curve of satiation score was 900.0 ± 266.9 satiation-unit·mL. The area-under-curve of IGP showed significant associations with maximum tolerated volume (ρ: -0.702; D: 0.234) and the area-under-curve of satiation score (D: 0.119): all p < 0.01. No correlations were found between volumetric with manometric and subjective NDT GA parameters.

SPECT/CT and HRM-NDT are feasible and tolerable techniques for measuring GA in healthy individuals. Thus, determining their diagnostic utility among patient populations requires further optimization and standardization.