Diagnostic ultrasound ( PDFDrive )

CHAPTER 54 Pediatric Pelvic Sonography 1907
mechanical obstruction and vesicoureteral relux. In ureterovesical
junction obstruction the distal ureter is dilated but may
taper, making it diicult to visualize at the level of the bladder
trigone, and at times, ureteral peristalsis is absent (Fig. 54.60).
Sonography is useful for identiication of a stone as the cause of
distal ureteral obstruction (Fig. 54.61). With vesicoureteral relux
the ureterovesical junction is oten gaping or patulous, and active
peristalsis is demonstrated. 94,204 In patients with a dilated tubular
structure posterior to the bladder, Doppler ultrasound can be
used to diferentiate a ureter, artery, or vein. In addition, color
Doppler sonography allows reliable visualization of the ureteric
jet phenomenon.
Marshall and colleagues 205 found that the distance of the
ureteric oriice from the midline of the bladder correlated with
vesicoureteric relux when the mean distance was 10.25 mm ±
P
FIG. 54.59 Urethral Stone in Fossa Navicularis. Sagittal image of
penis (P) using stepoff pad reveals a 7-mm calculus (arrow) in the distal
urethra of this 6-year-old boy with gross hematuria, dysuria, and suprapubic
pain.
2.40 SD. Jequier and colleagues 206 used color Doppler imaging
to show that (1) the duration of the ureteric jet varied from 0.4
to 7.5 seconds and depended largely on luid intake, (2) the
direction of the normal jet was anteromedial and upward, (3)
jets from reluxing ureters could appear normal, and (4) Doppler
analyses of the ureteric jet do not allow either the diagnosis or
the exclusion of vesicoureteral relux. 206 Berrocal and colleagues 207
demonstrated that cystosonography with SHU 508A appears
comparable to VCUG in the depiction of vesicoureteral relux.
Darge and colleagues 208 showed that the number of VCUG
procedures was signiicantly reduced as a result of implementation
of voiding urosonography using the intravesical application of
the ultrasound contrast agent Levovist.
Neurogenic or Dysfunctional Bladder
Urinary tract sonography has become a routine screening
procedure in children with neurogenic or dysfunctional bladders.
he most common cause of neurogenic bladder in children is
myelomeningocele. Other acquired forms of dysfunctional
bladder include traumatic paraplegia, cerebral palsy, spinal
cord tumor, and encephalitis or transverse myelitis. hese
children have a higher incidence of UTI, bladder stones, and
relux. Sonography of a neurogenic bladder demonstrates an
irregularly thickened, trabeculated bladder wall, oten with
multiple diverticula. Echogenic material within the bladder lumen
may represent complications of infection, hemorrhage, stone
formation, or foreign body insertion via the urethra. 209 Ultrasound
can also be used to assess the patient’s ability to empty the bladder
spontaneously or ater Credé maneuver or catheterization.
Residual urine volumes can be measured. 210
Urachal anomalies can be identiied on ultrasound when there
is persistence of the embryonic tract between the dome of the
bladder and umbilicus. Cacciarelli and colleagues 211 identiied
a normal urachal remnant in 62% of bladder sonograms in
children. 10,212 A normal urachal remnant appears as a small (6 mm
depth × 13 mm length × 12 mm width), elliptical, hypoechoic
structure located posterior to the rectus abdominis muscle and
A
B
FIG. 54.60 Congenital Ureterovesical Junction (UVJ) Obstruction in Infant With Urinary Tract Infection. (A) Sagittal view of the left
kidney reveals severe hydronephrosis with a markedly thin parenchyma with compression of the corticomedullary differentiation. (B) Sagittal
sonogram of the bladder (B) shows the dilated ureter, which tapers inferiorly at the UVJ (arrow).