Factors associated with renal parenchymal echogenicity in the newborn

A prospective renal ultrasound study of 134 newborns (49 prematures weighing less than 2500 g and 85 more mature babies) was undertaken to investigate factors associated with increased renal cortical echogenicity (RCE). Increased RCE was seen in 39 (29 per cent) babies. It was significantly related to body weight, age, medical status, blood urea nitrogen, and serum creatinine. In view of the interdependence of these factors, however, multivariate analysis was performed, which revealed that age was the most important factor associated with increased echogenicity (r = -0.46), and the other factors had only small independent effects, increasing the multiple r to 0.56. The authors conclude that an infant's immaturity is the most important determinant of increased RCE.