Volume of the spleen in children as measured on CT scans: normal standards as a function of body weight.

OBJECTIVE: The purpose of this study was to develop standards for the normal volume of the spleen in children as measured on CT scans. SUBJECTS AND METHODS: CT scans were used to measure the volume of the spleen in 48 children (30 boys and 18 girls), 1 day to 18 years old (mean and median ages were 8.2 and 7.8 years, respectively). Children who had underlying malignant tumors, infection, hematologic diseases, or other conditions that could alter splenic size were excluded. The area of the spleen on each axial section was determined by tracing its outline on the CT monitor and measuring the area of the region of interest. The area of the spleen on each section was multiplied by the slice thickness to calculate the volume of the spleen for each section. The total volume of the spleen was then determined by adding the individual volumes for each of the sections through the spleen. This method of calculating splenic volume has been validated in previous studies in adult subjects. The volume of the spleen was analyzed as a function of both body weight and age. RESULTS: The volume of the spleen correlated better with body weight than with age. The best regression model (r = .85) was a linear relationship as follows: splenic volume (cm3) = 0.7 + [4.6 x weight (kg)]. Using these data and a regression model, we generated standards for normal volume of the spleen as a function of body weight (with 95% tolerance intervals). CONCLUSION: We have developed CT standards for normal splenic volume in children. These standards can be used to objectively measure the size of the spleen in children who have clinically suspected splenomegaly.