Ultrasound assessment of mild splenomegaly: spleen/kidney ratio

Abstract

Background. Ultrasound may detect mild splenomegaly before it is clinically palpable. Knowledge of the normal range of spleen size in the population being examined is a prerequisite. Racial differences in splenic length could result in incorrect interpretation of splenic measurements. Objective. To measure the normal values of splenic length in Hong Kong Chinese children and compare the results with Western data; to determine whether there is a constant ratio of the length of the spleen to the left kidney, which could be used to diagnose splenomegaly without reference to a nomogram. Materials and methods. Ultrasound was used to measure maximum splenic and left kidney length in 256 Chinese children to obtain normal values for spleen length and to determine the spleen/kidney ratio. Results. Splenic length in Chinese children is similar to Western children up to the age of about 15 years. The spleen/left kidney ratio is strikingly constant with a mean value of 1. Using 2 SD above the mean as a guide, the upper limit of normal for the spleen/kidney ratio is 1.25. Conclusion. Splenomegaly should be suspected in children if the spleen is more than 1.25 times longer than the adjacent kidney.