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Parvati Ramchandani, MD
Genitourinary Fluoroscopic
examinations
1. What are genitourinary fluoroscopic examinations?
Genitourinary fluoroscopic examinations are studies that require “real-time” observation using fluoroscopy so
that maximal information is obtained about the anatomy of the structure being studied; some studies also provide
physiologic information about function. Contrast agent is injected into the various portions of the urinary tract for these
examinations. Examples are retrograde pyelograms for evaluation of the upper urinary tract, cystogram or voiding
cystourethrogram (VCUG) to evaluate the lower urinary tract, retrograde urethrogram (RUG) to evaluate the urethra, and
hysterosalpingogram to evaluate the uterus and fallopian tubes.
2. How are retrograde pyelograms and intravenous urograms (IVUs) different? Do they
provide the same information?
For a retrograde pyelogram, cystoscopy is performed (most often by a urologist), and a catheter is placed into the
renal pelvis. Contrast agent is injected through this catheter under fluoroscopic guidance to evaluate the lumen of the
pyelocalyceal system and the ureter for mucosal abnormalities, such as transitional cell carcinoma.
As discussed in Chapter 21, IVU requires intravenous administration of contrast agent, and it provides physiologic
information about the function of the kidney, in addition to depicting the anatomy of the renal parenchyma and the
collecting systems. A retrograde pyelogram provides only anatomic information about the lumen of the collecting
system, but the depiction of the anatomy is superior to that seen with IVU.
A retrograde pyelogram is performed if the patient cannot
receive an intravenous contrast agent because of renal
insufficiency or a history of severe contrast agent allergy.
Retrograde examination can also be performed if IVU fails
to show the entire pyelocalyceal system or ureter or to
evaluate further an abnormality seen on IVU.
3. What is the difference between a
cystogram and VCUG?
A cystogram is tailored to evaluate the urinary
bladder alone, whereas VCUG includes evaluation
of the bladder neck and urethra under fluoroscopic
observation. Both studies require injection of
radiographic contrast agent into the urinary bladder
through either an indwelling bladder drainage catheter
or a catheter placed in the urinary bladder solely for
the procedure. A cystogram is limited to images of the
bladder, whereas in VCUG, the catheter is removed
after the bladder has been distended with contrast
agent, and the patient voids under fluoroscopic
observation so that the bladder neck and urethra can
also be evaluated.
4. What are the indications for cystogram
and VCUG?
These studies can be performed to evaluate the
anatomy of the bladder and urethra in patients with
voiding dysfunction or recurrent urinary tract infections
(UTIs) (
), to look for a leak or fistula from the
bladder after surgery or abdominal trauma (
),
B
D
Figure 22-1.
Cystogram in a 70-year-old man with complaints
of incomplete emptying. There is a large bladder diverticulum (D)
arising from the left side of the urinary bladder (B) with a wide neck
(single arrow). When the patient voids, contrast agent (and urine)
fills the diverticulum and then flows back into the urinary bladder
when voiding stops, accounting for the patient’s symptoms of
incomplete emptying. The urine stasis in a bladder diverticulum can
be associated with the formation of stones or recurrent UTIs. The
double arrows point to a surgical clip in the pelvis from a previous
surgery.
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Genitourinary tract
to evaluate vesicoureteral reflux (VUR), or to evaluate
urinary incontinence.
5. Is a cystogram sensitive in excluding
a leak from the bladder?
Yes, but only if the study is performed in the correct
manner. It is important to distend the urinary bladder
with contrast agent until a detrusor contraction
occurs, which indicates that the bladder capacity
has been reached. Otherwise, small leaks may not
be shown. There is a great deal of variation in the
amount of bladder filling required to produce a
detrusor contraction, but most patients require 300
to 600 mL of contrast agent to reach this point. A
detrusor contraction is recognized by one of the
following: (1) the patient voids, (2) there is resistance
to injection of contrast agent through a hand-held
syringe so that the barrel of the syringe starts to
move back, or (3) flow through a contrast agent–filled
bag 35 to 40 cm above the fluoroscopy table stops or
reverses.
6. A patient is brought to the emergency
department with blunt abdominal
trauma and pelvic fractures. Does this patient need both an abdominopelvic
computed tomography (CT) scan and a fluoroscopic cystogram?
No. The bladder can be distended with contrast agent on the CT table (termed CT cystogram) to evaluate for a
leak. CT cystogram is as sensitive as a fluoroscopic cystogram, if not more so, in excluding a leak from the urinary
bladder. Before placing a catheter in the urinary bladder in a patient with pelvic fractures, however, the urethra
should be evaluated with RUG, and a catheter should be advanced through the urethra only if there is no urethral
injury. Failure to follow this sequence could cause a partial urethral injury to become a complete urethral disruption.
7. Why is VUR important? How is it shown?
VUR in children can cause recurrent UTIs and lead to permanent renal scarring, termed reflux nephropathy. This
condition can cause complications such as hypertension and renal insufficiency; 10% to 30% of all cases of end-stage
renal disease may be related to reflux nephropathy. In adults, VUR has less clinical significance, although it can be
associated with recurrent UTI and, rarely, even flank pain. VUR is reliably shown by fluoroscopically monitored VCUG. If
the bladder is not distended to the point of voiding, VUR may not be shown. In children, radionuclide cystography is an
alternative study to minimize the radiation exposure to pelvic organs.
8. What is RUG?
RUG is a study used primarily to evaluate the anterior urethra in men (
). The male urethra is divided into
two portions: the posterior urethra, consisting of the prostatic and membranous urethra, and the anterior urethra,
consisting of the bulbar and pendulous urethra. The external urethral sphincter, located in the urogenital diaphragm,
demarcates the posterior urethra from the anterior urethra. The posterior urethra has smooth muscle that relaxes when
the detrusor muscle contracts during voiding and is best seen on VCUG. Although visualized on VCUG, the anterior
urethra is better evaluated by RUG, which is performed by placing a Foley catheter in the tip of the penis and injecting
contrast agent under fluoroscopic guidance. The urethra is usually opacified only to the level of the external sphincter
on RUG because the sphincter is contracted in the nonvoiding state, and contrast agent cannot flow proximal to it.
9. How is the female urethra evaluated?
The entire female urethra is well shown on VCUG (
). The short length of the female urethra makes RUG
a difficult and unnecessary procedure in women.
10. What is a loopogram?
In patients who have undergone cystectomy (usually performed for muscle-invasive bladder cancer), the ureters
are connected to a loop of ileum known as an ileal conduit. The ileal conduit is excluded from the intestinal stream
and is connected to the anterior abdominal wall through a stoma; a urinary drainage bag is usually applied to the
stoma site. A loopogram is performed to evaluate the conduit and the upper urinary tracts. A catheter is placed
in the ileal conduit, and contrast agent is injected under fluoroscopic guidance until it refluxes in a retrograde
fashion into the ureters and the pyelocalyceal systems.
B
V
Figure 22-2.
VCUG in a 40-year-old woman with vaginal leakage
after hysterectomy. There is a fistula (arrow) between the posterior
aspect of the urinary bladder (B) and the vagina (V). Vesicovaginal
fistulas can be a complication of hysterectomy; difficult vaginal
delivery, particularly if forceps are used; cesarean section; and
gynecologic neoplasms, such as cervical cancer.
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Genitourinary Fluoroscopic examinations
11. What is a hysterosalpingogram?
A hysterosalpingogram is a study to evaluate
the uterine cavity and the fallopian tubes
(
). After sterile cleansing of the vaginal
canal and the exocervix, a cannula is placed
in the external cervical os, and contrast agent
is injected under fluoroscopic guidance. The
procedure is performed in women with primary
or secondary infertility and in women with
recurrent miscarriages.
12. Does magnetic resonance
imaging (MRI) or ultrasound
(US) examination of the pelvis
provide the same information as
hysterosalpingogram?
MRI and US are excellent at showing the
uterus, but both studies are poor at showing the
normal fallopian tubes. Dilated fallopian tubes
(hydrosalpinx) can be identified on MRI and
ultrasound, but abnormality in nondilated
tubes is best seen on a hysterosalpingogram
(
).
13. If I have a female patient with a
pelvic mass, what study would be
helpful in further evaluation?
Either MRI or US would be useful to determine
the organ of origin of the mass (gynecologic vs.
nongynecologic mass, uterine vs. ovarian origin)
and to characterize it further. Hysterosalpingogram
has no role in this situation.
14. What about a postmenopausal patient with vaginal bleeding? Would
hysterosalpingogram be helpful in evaluating the endometrium in this patient?
Endometrial abnormalities, such as endometrial hyperplasia or endometrial cancer, can cause perimenopausal/
postmenopausal bleeding and are best evaluated by transvaginal US or pelvic MRI.
A
B
Figure 22-3.
RUG in a 30-year-old man with history of gonorrhea.
A, The balloon of the Foley catheter (arrow) is in the tip of the penis
and has been distended with contrast agent. The balloon is usually placed in the fossa navicularis, which is an area of natural widening
in the glans penis.
B, The anterior urethra is opacified with contrast agent. Multiple strictures (arrows) in the penile urethra are typical
of inflammatory disease. The bulbar urethra is the urethral segment proximal to the arrows. The wide caliber of the proximal bulbar urethra
is the normal appearance of this segment of the bulbar urethra.
Figure 22-4.
VCUG in a 34-year-old woman. A large pocket of contrast
agent on the posterior aspect of the urethra represents a urethral
diverticulum (arrows). A urethral diverticulum is usually the result of
infection in periurethral glands, which decompress into the urethra
and result in a communicating cavity. Patients present with postvoid
dribbling, perineal discomfort, or recurrent UTIs.
Genitourinary Fluoroscopic examinations
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Genitourinary tract
B
iBliography
[1] N.R. Dunnick, C.M. Sandler, J.H. Newhouse, E.S. Amis (Eds.), Textbook of Uroradiology, third ed., Lippincott Williams & Wilkins, Philadelphia, 2001.
[2] C.M. Sandler, S.M. Goldman, A. Kawashima, Lower urinary tract trauma, World J. Urol. 16 (1998) 69–75.
[3] J.P. Vaccaro, J.M. Brody, CT cystography in the evaluation of major bladder trauma, Radiographics 20 (2000) 1373–1381.
Figure 22-5.
Normal hysterosalpingogram in a young woman with
primary infertility. The metal cannula within the external os is seen at
the bottom of the figure. The uterine cavity and both fallopian tubes
appear normal. There is contrast agent spilling from both tubes into
the pelvic peritoneal cavity, which is a normal finding.
Figure 22-6.
Hysterosalpingogram in a woman with a history of
pelvic inflammatory disease. Outpouchings of contrast agent (arrows)
are seen in the proximal portions of both fallopian tubes, a sequela of
prior pelvic inflammatory disease. This condition is termed salpingitis
isthmica nodosa, and it is associated with tubal dysmotility and
infertility. This diagnosis would be difficult to make with any other
imaging modality. The patient was advised to consider in vitro
fertilization.
Key Points: Genitourinary Fluoroscopic Examinations
1. Diagnosing small leaks from the urinary bladder requires adequate distention until a detrusor contraction occurs,
regardless of whether the evaluation is performed with CT or fluoroscopy.
2. The anterior urethra in men is better evaluated on RUG. The posterior urethra in men is better evaluated on VCUG.
3. In a man with pelvic trauma, the urethra should be evaluated with RUG before placement of a bladder drainage
catheter.
4. A retrograde pyelogram is an alternative study to IVU to evaluate the urothelium in patients in whom intravenous
contrast administration is contraindicated.
5. A hysterosalpingogram is the most useful imaging study to evaluate the uterus and the fallopian tubes in patients
with infertility.