Diagnostic Ultrasound - Abdomen and Pelvis

Ureteral Ectopia
TERMINOLOGY
Abbreviations
• Ectopic ureter (EU)
Definitions
• Ureter that does not terminate at bladder trigone
• Common usage: Ureter that terminates outside bladder
(extravesicular)
IMAGING
General Features
• Best diagnostic clue
○ 70-80% associated with complete ureteral duplication
○ Dilated ureter that extends beyond bladder
• Location
○ Intravesicular insertion with complete ureteral
duplication
– Weigert-Meyer rule: Upper moiety ureter inserts
inferior and medial to lower moiety ureter
– Results of Weigert-Meyer rule
□ Upper pole tends to obstruct
□ Lower pole tends to have vesicoureteral reflux
○ Extravesicular insertion
– Males: Prostatic urethra most common insertion site
□ Prostatic urethra: 54%, seminal vesicle: 28%, vas
deferens: 10%, ejaculatory duct: 8%
– Females: Vestibule or urethra most common insertion
site
□ Vestibule: 38%, urethra: 32%, vagina: 27%, uterus
or cervix: 3%
○ 5-17% of EUs are bilateral
• Morphology
○ Orifice commonly stenotic, leading to obstruction of
renal moiety
Ultrasonographic Findings
• Grayscale ultrasound
○ Dilated ureter extends beyond bladder trigone
– Transrectal/transvaginal US may delineate site of
insertion
○ Ureterocele may be present if ectopic vesicular insertion
○ Hydronephrotic or dysplastic renal moiety
○ Detection of fetal hydronephrosis may be earliest sign
• Color Doppler
○ Ureteral jet can be used to identify ectopic intravesicular
insertion
○ Compare normal position of contralateral ureteral jet at
interureteric bar
Radiographic Findings
• IVP
○ Complete ureteral duplication
– Dilated upper pole collecting system
– Nonvisualization of upper pole moiety with severe
obstruction/dysplasia
□ Visualized lower pole moiety: Fewer calyces than
normal for entire kidney
□ Lower pole displaced inferolaterally by obstructed
upper pole ("drooping lily" sign)
○ Single-system ectopic ureter (SSEU): Usually small,
dysplastic, and nonfunctioning kidney
Fluoroscopic Findings
• Voiding cystourethrogram
○ Early filling defect in bladder may reflect presence of
ureterocele
○ Look for reflux into either moiety, most commonly,
lower
○ May locate insertion of EU if within urinary tract (bladder
neck or posterior urethra)
CT Findings
• CECT
○ Hydronephrotic upper moiety with variable function
○ Dilated, tortuous ureter to level of insertion
○ Males with SSEUs: Dilated ipsilateral seminal vesicle
○ May be used occasionally to locate small, poorly
functioning, dysplastic kidney
MR Findings
• T2WI
○ High signal intensity fluid within collecting system
○ With obstruction, tortuous dilated ureter can be
followed to level of ectopic insertion
○ High signal cystic dysplasia of upper pole moiety
• T1WI C+
○ Poor or little excretion when upper moiety is obstructed
○ Delayed images can demonstrate whole course of ureter
to level of ectopic insertion
Nuclear Medicine Findings
• Renal scintigraphy
○ Assess relative function, drainage, and scarring, which is
important for surgical planning
Imaging Recommendations
• Best imaging tool
○ Ultrasound and CT/MR urography
– MR urography can display ectopic ureteral insertions,
even those outside urinary tract
○ CT may be useful to locate small, poorly functioning,
dysplastic kidney with single EU
○ VCUG to exclude reflux in complete ureteral duplication
• Protocol advice
○ Trace dilated ureter on US to its termination below
bladder
DIFFERENTIAL DIAGNOSIS
Bladder Diverticulum
• Fluid-filled round or ovoid outpouching from bladder, with
neck
Hydrosalpinx
• Also tubular but has incomplete septa and tiny mural folds
• Anechoic and thin walled when chronic
• Thick walled with internal debris and thicker folds when
acutely infected in pelvic inflammatory disease
• Does not course in craniocaudal direction
Dilated Pelvic Vessels
• Typically more numerous
Diagnoses: Urinary Tract
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