Does appendiceal diameter change with age? A sonographic study

Abstract

OBJECTIVE. The purposes of this study were to determine whether age-related changes in appendiceal diameter identified on CT and pathology are apparent on sonography and to assess the relationship between normal appendiceal diameter and patient-specific factors. MATERIALS AND METHODS. Ultrasound examinations from 388 unique pediatric patients with normal appendixes, evenly distributed by age, were reviewed. Appendiceal diameter and wall thickness were correlated with patient age, sex, height, weight, and presence of enlarged lymph nodes. RESULTS. Mean (± SD) anteroposterior and transverse appendiceal diameters were 4.4 ±0.9 and 5.1 ± 1.0 mm, respectively. Appendiceal diameter was normally distributed across the population but was not significantly associated with age. Centers for Disease Control and Prevention (CDC) weight percentile for age was the only statistically significant patient-specific predictor of transverse diameter (p = 0.001) and approached significance for anteroposterior diameter (p = 0.051). The presence of enlarged lymph nodes was a significant predictor of anteroposterior diameter (p = 0.029) and approached significance for transverse diameter (p = 0.07). Wall thickness was normally distributed across the population and was significantly associated with age (p = 0.011; effect size, -0.05 mm/y). CONCLUSION. Appendiceal diameter measured on ultrasound is normally distributed in children and does not depend on age. Age-dependent diagnostic cutoffs for normal sonographic diameter are thus not needed. There is, however, a relationship between age and appendiceal wall thickness, suggesting the need for age-dependent diagnostic values if this criteria are to be used to diagnose appendicitis. Although the CDC weight percentile for age and the presence of enlarged lymph nodes affect appendiceal diameter on ultrasound, these effects are small and of doubtful clinical significance.