Assessment of nonrespiratory stomach motion in healthy volunteers in fasting and postprandial states

Abstract Purpose To characterize nonrespiratory stomach motion in the fasting state and postprandial. Methods and materials Ten healthy volunteers underwent 2-dimensional Fiesta cine magnetic resonance imaging studies in 30-second voluntary breath hold, in axial, coronal, and 2 oblique planes while fasting, and 5, 15, 30, 45, and 60 minutes postmeal. Each stomach contour was delineated and sampled with 200 points. Matching points were found for all contours in the same 30-second acquisition. Using deformable parametric analysis (Matlab, version 7.1), mean magnitude, and standard deviation of displacement of each point were determined for each patient. Maximal, minimal, and median population values in 6 cardinal, and in any direction, were calculated. Results The median of mean displacements for the baseline position of each point was small and rarely exceeded 1.1 mm; greatest value was 1.6 mm superior–inferior. Median displacement (pooled across time) in the right–left, superior–inferior, and anterior–posterior directions was 0.3 (range, −0.7 to 1.3), 0.8 (−0.4 to 2.4), and 0.3 (−1.1 to 1.6) mm, respectively. Fasting and postprandial standard deviation did not differ. Conclusions Nonrespiratory stomach displacement is small and stomach position is stable after a small, standard meal. Radiation therapy may be delivered at any time within the first hour after eating without significant compromise of planned planning target volumes.