Yonago Acta medica 1997;40:3142
A Study on Echogenic Changes of the Kidney-Spleen and Liver-Spleen Contrasts with Age in Infants and Children
Md. Abdus Samad, Hiroshi Hayashibara, Yasushi Utsunomiya and Kazuo Shiraki
Department of Pediatrics, Faculty of Medicine, Tottori University, Yonago 683,
Individual echogenicities of the kidneys and liver cannot be determined using only the generally accepted right kidney/liver contrast ratio. We therefore determined 5 new contrast ratios: i) left kidney to spleen (Kl/SP); ii) right kidney to spleen (Kr/SP); iii) liver to spleen (L/SP); iv) Kl/SP - Kr/L; and v) (Kl/SP)/(Kr/L); with the last 2 being designated as modified ratios alternative to the L/SP ratio. We used the new ratios with computerized histogram sonography to assess echogenicitic changes in the kidneys, liver and spleen with age for 257 normal children ranging from birth to 15 years old. The values in Kr/L, Kl/SP and Kr/SP increased from day 0 to day 2 in early neonates (values > 1), decreased between day 2 to 1 month, and thereafter remained constant. The values were < 1 from 1 month to 15 years. The values in L/SP ratio were constant from birth through 6 months (values > 1), and thereafter decreased gradually to a value of approximately 1 and remained constant in the later periods. We found the relationship Kl/SP < Kr/L in early neonates, Kl/SP > Kr/L in infants and Kl/SP < Kr/L again in the later periods. These results suggest that the renal cortical echogenicity was higher than that of the liver and splenic parenchyma in early neonates and that the echogenicity of the liver was greater than that of the spleen in children from birth to 6 months. Combining these ratios is thus helpful for assessing renal and hepatic echogenicity individually. Moreover, significantly higher echogenicity of the liver was observed in patients with hepatic dysfunction (n = 21) for children of all age groups, as observed by the L/SP contrast ratio. Significantly increased echogenicity of the liver was observed by modified ratios in children aged 1 year or older. We suspect that the L/SP and modified ratios are useful for assessing the echogenicity of the liver in patients with liver dysfunction.
Key words: childhood; computerized histogram sonography; liver; kidneys; spleen