Comparing the use of geometric mean and anterior only data in gastric emptying studies

Objectives The SNMMI suggests that a gastric emptying procedure be performed using the geometric mean of counts obtained in anterior and posterior views. In some circumstances it is impossible to get both anterior and posterior views for certain patients, such as those who are bedridden or cannot stand for the appropriate length of time. The purpose of this study was to determine if using only counts obtained from an anterior view would yield the same diagnosis.

Methods This study looks into whether using anterior count data obtained during a gastric emptying study is sufficient when posterior data is unable to be collected. 43 patients were selected from Froedtert Hospital, where the procedures were performed between August 2012 and October 2012. All patients studied ate chicken livers injected with Tc-99m Sulfur Colloid and mixed with a microwavable beef stew. The count results were then studied using both the anterior count information only and the geometric mean of posterior and anterior count information. Statistical analysis was performed in order to compare the two sets of data.

Results It was determined that 14% of patients had a change in their overall diagnosis using the anterior only data. A Chi-Square Test was performed using one degree of freedom and a predetermined level of significance of .05. A Chi-Square value of 9.66 was calculated and a p-value of <.01 was obtained. Thus, since the p-value is less than our level of significance, a significant difference was seen between the geometric mean and anterior only data.

Conclusions From this study, it can be concluded that substituting a procedure utilizing only anterior image data is not as diagnostically accurate due to the significant difference seen in the statistical comparison. Further studies should be performed looking into result changes when left anterior oblique views are collected instead.

Research Support Donohoe, K., Maurer, A., Ziessman, H., Urbain, J., Royal, H., and Martin-Comin, J. (2009, July). Procedure Guideline for Solid Gastric-Emptying Study 3.0. Retrieved from http://www.snm.org/guidelines.