Objectives: The geometric mean is the recommended method for calculating gastric emptying in adults to correct for variable attenuation during the study. In children, it has been reported that a single posterior acquisition is sufficient. Our objective was to evaluate the relation between the values of gastric emptying in children obtained by posterior view only and by the geometric mean of conjugate anterior and posterior views.
Methods: The gastric residual of a standard meal was calculated in 81 children of different ages. The calculation of the gastric residual was performed with different methods, posterior only and geometric mean of anterior and posterior acquisitions. The variation between these 2 methods was evaluated in different age groups and different body weights.
Results: There was a high correlation (r = 0.942) between the values using posterior as compared with geometric mean for all of the patients. For children younger than 8 years and weighing <30 kg, there was no significant difference between the 2 methods for either liquid or solid meals (P = 0.89 and P = 0.11 for age; P = 0.95 and P = 0.80 for weight). For children older than 8 years and weighing >30 kg, there was no significant difference between the 2 methods for liquids (P = 0.57 for age; P = 0.69 for weight), but there was a significant difference with solids (P < 0.0001 for both age and weight).
Conclusions: In children younger than 8 years and weighing <30 kg, acquisition of a single posterior image is sufficient for calculating gastric emptying at 1 hour postingestion for either liquid or solid meals. In children older than 8 years and weighing >30 kg, acquisition of both anterior and posterior images with geometric mean calculation is recommended when a solid meal is used. If a liquid meal is used in patients older than 8 years, the posterior only may be adequate.
*Department of Radiology
†Department of Anesthesia, Children's Hospital Boston, Harvard Medical School, Boston, MA.
Address correspondence and reprint requests to Laura A. Drubach, MD, Department of Radiology, Children's Hospital Boston, 300 Longwood Ave, Boston, MA 02115 (e-mail: email@example.com).
Received 1 August, 2011
Accepted 6 February, 2012
The authors report no conflicts of interest.