CHAPTER 22 170 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) (Fig. 22-1), to look for a leak or fistula from the bladder after surgery or abdominal trauma (Fig. 22-2), 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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Chap
ter
22Parvati Ramchandani, MD
Genitourinary Fluoroscopic examinations
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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.
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.
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) (Fig. 22-1), to look for a leak or fistula from the bladder after surgery or abdominal trauma (Fig. 22-2),
171Genitourinary tract
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.
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
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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 (Fig. 22-3). 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 (Fig. 22-4). The short length of the female urethra makes RUG a difficult and unnecessary procedure in women.
0. 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.
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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.
11. What is a hysterosalpingogram?A hysterosalpingogram is a study to evaluate the uterine cavity and the fallopian tubes (Fig. 22-5). 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 (Fig. 22-6).
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.
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.
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.
BiBliography
[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.
