In routine sonographic evaluation, healthy children demonstrate homogenous splenic echogenicity that is slightly lower than that of healthy liver tissue. Detailed discrimination between red and white splenic pulp can be accomplished by using a higher-frequency linear transducer (10–13 MHz). The white pulp is typically lower in echogenicity. It is important to remember that the lymphatic system and lymphatic follicles are not completely formed in newborns and infants, so the volume of the white pulp increases with age.

A complete ultrasonographic evaluation of the spleen should always include Doppler flow studies of the surrounding and intraparenchymatous vessels. The architecture of the spleen is predominantly determined by the vascular structure. The spleen is mainly supplied by the splenic artery, which arises from the celiac trunk and in most (80 %) cases traverses along the upper border of the pancreas. Close to the hilum, it separates into two (80 %) or three (20 %) lobar arteries. These lobar arteries supply segments that typically do not form any collaterals between each other, which are important for spleen-preserving surgery. The spleen also obtains some blood from the short gastric vessels arising from the gastroepiploic artery.

Venous drainage is accomplished via the hilum into the splenic vein, which joins the mesenteric vein to form the portal vein. Therefore, splenomegaly may result from portal hypertension. Normal spleen size, however, does not rule out portal hypertension. Therefore, evaluation of the splenic drainage should always include a careful evaluation of the liver as well.

Contrast enhanced ultrasound for splenic indications has not been well studied in children. In a study that included some children, contrast enhancement increased the sensitivity for detection of splenic lacerations after blunt abdominal trauma from 59 to 96 % [2]. The main disadvantage is that intravenous microbubbles of sulfur hexafluoride gas must be infused shortly before imaging.