Hyperechoic renal papillae as a physiological finding in neonates.
OBJECTIVE
The increased echogenicity of medullary pyramids in neonates and children is poorly understood. Hence we conducted a prospective ultrasound study of the kidneys of neonates and fetuses. Hence we conducted a prospective ultrasound study of the kidneys of neonates and fetuses.


METHODS
Ultrasound images of kidneys in neonates and fetuses in late pregnancy were analysed.


RESULTS
Thirteen percent of the studied neonates showed hyperechogenicity in the renal papillae that disappeared spontaneously within 1 week, although no hyperechoic papillae were seen in any of the fetuses. Urine volume of the neonates with hyperechogenicity was significantly less than that of those without it.


CONCLUSIONS
The fact that no hyperechoic findings appeared before the 34th week of gestation suggests that maturation of renal tubules and ability to concentrate urinary substances were contributing factors. Because only the tips of the pyramids were hyperechogenic, however, the term hyperechoic papillae would seem more appropriate than hyperechoic pyramids, the term generally used today.
Nakamura
M
M
Department of Clinical Pathology, Jichi Medical School, Tochigi, Japan.
Yokota
K
K
Chen
C
C
Taniguchi
N
N
Izumi
A
A
Kawai
F
F
Itoh
K
K
D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D007679:Kidney Medulla / Q000000981:diagnostic imaging* / Q000196:embryology; D008297:Male; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D016482:Urinalysis; D014556:Urine