Urogenital ImagingUreterocoele
a thin-walled
cystic swelling of the lowermost part of the
ureter in its path through the bladder muscle. Ureterocoeles may be either intravesical (in which the orifice of the
ureter and the
cyst itself protrude into the bladder
lumen) or ectopic (in which the ureterocoele is in the submucosa of the bladder and some part extends into the bladder neck or
urethra). A ureterocoele is believed to be the result of a defect in the muscular coat of the
ureter, and often a defect in the bladder wall itself.
Congenital stenosis of the ureteric orifice in the bladder wall is thought to give rise to ureterocoele, and it is commonly associated with ectopic ureters. It is relatively common in both children and young adults, and is bilateral in approximately 10% of cases. It is more likely to occur in females, and is often accompanied by other
congenital urinary tract anomalies. Ureterocoeles which occur on single ureters may also be intravesical (formerly referred to as simple ureterocoele) or ectopic. The ectopic ureterocoele is similar to a double
ureter. The orifice of the intravesical ureterocoele opens in the normal zone, but is stenotic. It is more common in women than in men, and is usually discovered in adults, unlike most ureterocoeles seen in children.
Most intravesical ureterocoeles are asymptomatic, but a large ureterocoele may block the bladder neck and even cause hydronephrosis. Ureterocoeles on duplex ureters may occur on the ureter draining the upper pole of the kidney, at the lower end of the common stem of a bifid ureter, or on a ureter draining the lower pole of the kidney. In adults, this type of ureterocoele is usually an incidental finding. However, it is more dangerous in infants and children and is the most common cause of acute bladder outlet obstruction in infant girls. It may also be responsible for chronic ureteric obstruction, renal back-pressure atrophy, or persistent urinary tract infection. Ureterocoeles on duplex ureters are more common in females, and the majority are unilateral, although they do occur bilaterally. These ureterocoeles also may be either intravesical or ectopic. Intravesical ureterocoeles on duplex ureters may be either stenotic or nonobstructed. Ectopic ureterocoeles always arise on the upper-pole ureter and may be sphincteric, sphincterostenotic, caecoureterocoeles, blind ectopic ureterocoeles or pseudoectopic ureterocoeles. The functional abnormalities caused by ureterocoeles can be identified with intravenous urography, voiding cystourethrography, percutaneous puncture, ultrasonography, scintigraphy or CT.
Imaging plays an essential role in the diagnosis of ureterocoeles which can be detected as an enlargement at the distal end of the ureter cobra head finding during intravenous urogram (Fig.1). On cystography, the ureterocoele is seen as a radiolucent filling defect in the urinary bladder (Fig.2). As ureterocoeles are very often diagnosed in children, and ultrasound is the primary imaging modality, the ultrasound findings of a ureterocoele have been well described. They are fluid-filled structures, oval in configuration, seen at the ureteric orifice, which has a thick wall around it. Their anatomical location and morphological configuration are classical of the diagnosis (Fig.3) (Fig.4). The ureterocoele can be equally well diagnosed on MRI (Fig.5). Regardless of whether the ureterocoele is simple or ectopic, imaging detection and the specific diagnosis is possible. Furthermore, imaging can be used for the evaluation of associated complications such as urinary obstruction.
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