Diagnostic ultrasound ( PDFDrive )

CHAPTER 52 The Pediatric Urinary Tract and Adrenal Glands 1781
FIG. 52.5 Ureteral Jets. Transverse bladder image shows bilateral
ureteral jets crossing each other.
and 1.5 mm (range 0.6-2.6), respectively. Strong positive correlations
were found between anterior and posterior wall thickness
and increased age and body mass index (BMI). However, in
contrast to the study of Jequier and Rousseau, there was no
correlation between bladder volume and anterior or posterior
wall thickness. Further studies are required in order to better
delineate the efects of measurement technique as well as patient
age, height, and BMI on bladder wall thickness.
Scans of the bladder are best performed with the bladder
comfortably full so that abnormalities, including wall thickening
and trabeculation, can be seen. Dilation of the distal ureters
and ureteroceles is also sought. he thickness of the bladder
wall may be increased with inlammation or muscular hypertrophy.
Postvoid views of the bladder and kidneys may be helpful
in patients with a neurogenic bladder or dilated upper collecting
system, because a distended bladder may cause increased dilation
but improve ater voiding.
Color Doppler sonography is used in selected clinical situations
to evaluate the ureteral jets 17,18 (Fig. 52.5).
Normal Renal Anatomy
hroughout the second trimester, the fetal kidney consists of a
collection of renunculi (small kidneys), each composed of a
central large pyramid with a thin peripheral rim of cortex. As
the renunculi progressively fuse, their adjoining cortices form
a column of Bertin. he former renunculi are then called “lobes.”
Remnants of these lobes with incomplete fusion are recognized
by a lobulated surface of the kidney. his “persistent fetal lobulation”
(Fig. 52.6) should not be confused with renal scarring 19
and may persist into adulthood. 20 Fetal lobulation is distinguished
from scarring by the presence of a smooth renal contour, regular
spacing, and absence of calyceal blunting. he indentations spare
the renal pyramids, unlike scarring, in which the renal parenchyma
overlying the pyramids appears thinned.
he renal junctional parenchymal defect (interrenicular
septum or issure) is the most prominent of these grooves,
FIG. 52.6 Fetal Lobulation. Longitudinal image of the right kidney
depicts a mildly undulating contour due to parenchymal indentations
that spare the pyramids (arrows).
FIG. 52.7 Renal Junctional Parenchymal Defect. Longitudinal image
of the right kidney reveals an echogenic groove extending obliquely
through the parenchyma (arrowheads).
extending from the hilum to the cortex, and is caused by perirenal
fat adherent to the renal capsule along a clet on the renal surface.
It is frequently seen in the anterosuperior aspect of the kidney 20
(Fig. 52.7). At birth, the pyramids are still large and hypoechoic
compared with the thin rim of echogenic cortex that surrounds
them. Glomerular iltration rate shortly ater birth is low and
increases rapidly ater the irst week postpartum. hroughout
childhood, there is signiicant growth of the cortex, and the
pyramids gradually become proportionately smaller.
he anatomy and sonographic appearance of the pediatric
kidney depend on age. 5,21,22 he normal infant kidney has several
features that difer from the normal adult kidney (Fig. 52.8). he