DOI:10.2214/AJR.06.0688
AJR 2007; 188:W390-W391
© American Roentgen Ray Society
Retroiliac Ureters with Bilateral Testicular Microlithiasis: Simultaneous MDCT Visualization of Ureters and Iliac Arteries with Biphasic Contrast Injection
Murat Kocaoglu,
Faysal Gok,
Yusuf Kibar and
Bilal Battal
Gulhane Military Medical School, Ankara 06018, Turkey
WEB—This is a Web exclusive article.
Retroiliac ureter is a rare cause of noncalculous low ureteral obstruction
[1]. The combination of
retroiliac ureter and testicular microlithiasis has not, to our knowledge,
been reported [2]. Moreover,
the multiplanar imaging appearance of retroiliac ureter has not been shown or
described in the literature, to our knowledge. We present MDCT urography
findings of this entity with a biphasic IV contrast material injection and
single scanning method used to visualize the ureters and iliac arteries
simultaneously.
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Fig. 1A —Bilateral retroiliac ureters and testicular microlithiasis in
13-year-old boy who presented with hematuria and recurrent urinary tract
infection. Abdominal sonography (not shown) revealed bilateral
hydroureteronephrosis and scarred left kidney. Thick-slab coronal reformation
CT image from biphasic contrast-enhanced MDCT data through both ureters shows
bilateral retroexternal iliac artery course of ureters (arrows) with
ureteral dilatation. Passage of contrast material distal to stenosis is also
seen.
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Fig. 1B —Bilateral retroiliac ureters and testicular microlithiasis in
13-year-old boy who presented with hematuria and recurrent urinary tract
infection. Abdominal sonography (not shown) revealed bilateral
hydroureteronephrosis and scarred left kidney. Volume-rendered reformation CT
image from biphasic contrast-enhanced MDCT data clearly shows simultaneous
contrast enhancement of retroiliac ureters (arrows) and iliac
arteries. Left kidney is small and has irregular contour. Bilateral hip
dislocation and right accessory renal artery are also noted.
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Fig. 1C —Bilateral retroiliac ureters and testicular microlithiasis in
13-year-old boy who presented with hematuria and recurrent urinary tract
infection. Abdominal sonography (not shown) revealed bilateral
hydroureteronephrosis and scarred left kidney. Longitudinal sonograms of
inguinal regions reveal bilateral undescended testes comprising multiple small
parenchymal echoes without acoustic shadowing, which is consistent with
testicular microlithiasis.
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Fig. 1D —Bilateral retroiliac ureters and testicular microlithiasis in
13-year-old boy who presented with hematuria and recurrent urinary tract
infection. Abdominal sonography (not shown) revealed bilateral
hydroureteronephrosis and scarred left kidney. Longitudinal sonograms of
inguinal regions reveal bilateral undescended testes comprising multiple small
parenchymal echoes without acoustic shadowing, which is consistent with
testicular microlithiasis.
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A 13-year-old boy with cerebral palsy and epilepsy was referred to our
department of radiology for the assessment of recurrent hematuria and urinary
tract infection. Excretory urography performed at another institution showed
delayed excretion of contrast material into the ureters and extrinsic
compression on the distal ureters. Sonography revealed atrophy of and scar
formation on the left kidney and revealed bilateral hydroureteronephrosis. A
voiding cystourethrogram was normal.
The parents of this patient would not consent for him to receive anesthetic
needed for MR urography, the multiplanar imaging method of choice at our
institution for pediatric urinary tract imaging. Because we strongly suspected
distal ureteral compression attributable to a vascular abnormality, we
performed MDCT urography using a modified technique. First, a half dose of IV
contrast material was administered. After a 30-minute delay for contrast
excretion, the second half dose was given immediately before CT.
Maximum-intensity-projection and volume-rendering images showed bilateral
retroexternal iliac ureters and proximal ureteral dilatation. Passage of
contrast material distal to the stenosis was shown fairly well on CT (Figs.
1A and
1B). The scanning parameters
included 90 kV and 80 mAs.
Scrotal and inguinal sonography showed bilateral testicular microlithiasis
with undescended testicles, which were located at the inguinal canals (Figs.
1C and
1D).
Several vascular abnormalities, such as crossing accessory renal arteries,
lumbar veins, retrocaval ureters, and ovarian vein syndrome, may be
responsible for ureteral obstruction. Retroiliac ureter is an infrequent
congenital condition that causes ureteral obstruction; infection; and
hematuria, presumably due to infection, to venous congestion of the ureteral
mucosa by the external arterial compression, or to both. During embryologic
progress, this entity occurs due to faulty migration of the kidneys. Only
fewer than 30 cases have been reported. Nguyen et al.
[1] reviewed the report of
retroiliac ureters and found 24 cases. Among the reviewed cases, they
identified only four cases with bilateral involvement.
Preoperative radiologic diagnosis of retroiliac ureter is usually
complicated and depends on a high level of suspicion. To date, all reported
cases have been shown during surgery or with indirect imaging findings on
excretory urography and catheter angiography without concurrent visualization
of obstructed ureters and arteries
[1]. On the basis of the
findings on previous imaging studies, we suspected vascular compression on the
distal ureters and used a biphasic contrast injection for a single scanning
MDCT technique to be able to see ureters and vascular structures
simultaneously.
With the advent of MDCT technology, 3D and multiplanar reconstruction of
the entire urinary tract have allowed acquisition of conventional urogram-like
images [3]. The main limitation
of MDCT is the increased risk of potentially substantial radiation exposure to
patients; however, studies have shown that appropriate diagnosis for urinary
tract disease is possible using low-dose CT urography
[4].
Several urogenital and extraurogenital abnormalities associated with
retroiliac ureters have been described, but none of those patients had
testicular microlithiasis. Testicular microlithiasis is a rare disease, and a
small number of pediatric cases have been reported. The coexistence of this
condition with malignancies has raised the suspicion that testicular
microlithiasis might be a premalignant lesion
[2].
A retroiliac ureter should be suspected in a patient with a varying degree
of upper urinary tract dilatation, especially if the diagnosis is undetermined
on excretory urography and sonography. The CT urography technique should be
modified by altering the mode of IV contrast material administration when
vessel compression is suspected as the cause of urinary tract obstruction. Our
case also stresses the importance of carefully examining the genital and
urologic systems when either is found to have a congenital abnormality.
References
- Nguyen DH, Koleilat N, Gonzalez R. Retroiliac ureter in a male
newborn with multiple genitourinary anomalies: case report and review of the
literature. J Urol 1989;141
: 1400-1403[Medline]
- Kocaoglu M, Bozlar U, Bulakbasi N, Saglam M, Ucoz T, Somuncu I.
Testicular microlithiasis in pediatric age group: ultrasonography findings and
literature review. Diagn Interv Radiol2005; 11:60
-65[Medline]
- Sheth S, Fishman EK. Multi-detector row CT of the kidneys and
urinary tract: techniques and applications in the diagnosis of benign
diseases. RadioGraphics 2004;24
: e20[Abstract/Free Full Text]
- Kosucu P, Ahmetoglu A, Imamoglu M, et al. Multislice computed
tomography urography after diuretic injection in children with urinary tract
dilatation. Acta Radiol 2004;45
: 95-101[CrossRef][Medline]
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