Factors that Influence Selecting the Imaging Modality for Diagnosing Acute Appendicitis

ABSTRACT

PURPOSE: The aim of this study is to evaluate the advanced radiographic imaging that's used for making the diagnosis of an acute appendicitis, and also the factors that influence selecting the imaging modality. METHODS: We retrospectively reviewed the data of 420 patients who underwent an appendectomy as an emergency procedure in our hospital from January 1, 2005, to December 31, 2006. All the cases were categorized into three groups by the radiologic imaging tests. One was the ultrasonography (US) only group, another was the computed tomography (CT) only group and the third was both the US and CT scan group. Age, gender, height, weight, the Alvarado score (AS) and the body mass index (BMI) were compared between the 3 groups. I assessed the reason for choosing computed tomography (CT) to assist in making the diagnosis. RESULTS: Four hundred twenty patients underwent operative exploration under the presumed diagnosis of appendicitis. Of those, 348 patients underwent US, 48 underwent CT scanning and 24 underwent both US and CT scanning. The mean age and BMI were significantly higher in the CT only group (P<0.001 and P=0.008, respectively). The most common reason for choosing CT scanning was that the physician suspected other diseases other than appendicitis due to an atypical presentation on the physical examination. CONCLUSION: US was the most commonly used radiologic imaging study for making the diagnosis of appendicitis. CT was more frequently used for the old or obese patients for making the differential diagnosis.