# Diagnosis of Female Diverticula Using Magnetic Resonance Imaging

Authors: Sima Porten; Stephanie Kielb
Journal: Advances in Urology
 (2008)

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## Abstract

We investigate the
ability of physical exam to diagnose urethral
diverticula with or without magnetic resonance
imaging (MRI) and exclusive of invasive
modalities. A retrospective chart review of all
women undergoing urethral diverticulectomy at
our institution since 1999 was performed. We
identified 28 female patients with a mean age at
diagnosis of 42.6 years (range 18–66).
Common presenting symptoms included dyspareunia,
urgency, and frequency. Physical exam revealed a
suspected urethral diverticulum in 26
(92.9%) patients, which was confirmed
postoperatively in 17 of the 20 (85%) women
who underwent surgical resection. Noninvasive
imaging modalities (MRI or CT) were available
for review in 20 (71%) cases and made the
correct diagnosis of urethral diverticulum
(presence or absence) in 19 (95%) patients.
In those patients with symptoms of stress or
urge incontinence (11, 39%), voiding
cystourethrogram (VCUG) was performed. Urethral
diverticula are often easily diagnosed on physical
exam. MRI can be a useful adjunct for defining
diverticular extent in surgical planning,
especially for proximal and complex diverticula,
and should be the modality of choice if clinical
suspicion is high based on patient symptoms
and physical exam.


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## Body

## 1. Introduction

The incidence
of urethral diverticula is thought to occur in 1–5% of the general
female population [1, 2].  Presenting
symptoms classically consist
of dysuria, post void dribbling, dyspareunia, recurrent urinary tract infections
(UTI), and stress incontinence. In fact, studies suggest that 1.4% of patients
with stress incontinence have a urethral diverticulum [3]. Clinical diagnosis can be difficult due to the
nonspecific nature of presenting symptoms and the possibility of concomitant
genitourinary pathology.However, it
has been shown that in about 60% of cases a careful and thorough physical exam
can make an accurate diagnosis of urethral diverticulum [3].  Ancillary modalities such as cystoscopy,
voiding cystourethrogram (VCUG), and urethrography are reported to be
diagnostic in 65–96% of cases,
depending on the study [4–7].  Traditionally, the gold standard of diagnosis
has been one or more of these ancillary and invasive techniques.These invasive studies are difficult
to perform properly and can be quite uncomfortable for patients. Recent
advances and improvements in magnetic resonance imaging (MRI) have increased
its use in the diagnosis of urethral pathology. MRI has multiplanar imaging
capabilities with excellent tissue contrast, especially on T2-weighted images.
Gadolinium enhancement can help define internal diverticular architecture [7].
Isolated studies in past literature demonstrated MRI to have a high sensitivity
in the diagnosis of urethral diverticulum [7–10].  We report on a cohort of contemporary cases
to determine whether the diagnosis of urethral diverticulum can be made on
physical exam with or without MRI, exclusive of invasive cystoscopy or  VCUG.


## 2. Materials and Methods

Following IRB
approval, female patients diagnosed with urethral diverticulum from 1999 to
2004 were identified by a retrospective chart review using electronic medical
records and paper charts. Information about presenting symptoms, urological
history, diagnosis method, imaging studies, and outcomes at last followup was
documented. Surgical operative reports and pathology reports were also reviewed
for final diagnosis.Cases were reviewed to assess the
method of initial diagnosis (physical exam, MRI, VCUG, cystoscopy, or
urethrography). Our goal was to determine how the diverticula were diagnosed
and to determine what studies were most sensitive at making the diagnosis.
Therefore, any additional studies, as well as their contribution to diagnosis
and surgical planning, were recorded. Outcomes at last followup were correlated with the type of
imaging modality used for diagnosis and/or surgical planning.MRI studies (if obtained) were
performed at this institution using a 1.5 Tessla magnet with a phase-array pelvic coil.
Axial, coronal, and sagittal T2 weighted sequences were obtained using fast
spin echo technique. Axial and sagittal T1 weighted sequences were obtained
before and after intravenous gadolinium contrast. Computer tomographic (CT)
scans were used in four cases due to clinical contraindications for MRI.


## 3. Results

We identified 28 female patients with
a mean age at diagnosis of 42.6 years (range 18–66). The most
common symptoms were dyspareunia in 13 (46%), urgency in 11 (39%), and
frequency in 9 (32%) patients. Recurrent UTIs were common, occurring in 13
(46%) women; in one patient, it was the only symptom present. Of the patients
with incontinence, 5 (18%) described post void dribbling characteristic for urethral diverticulum.
Stress incontinence was present in 9 (32%) patients
(Table1).  On physical exam, 26 (92.9%) patients were
suspected to have a urethral diverticulum based on a visualized or palpable
mass. Purulent material was expressed by compression in 3 (11.5%) masses.  Of these patients, 20 (77%) underwent
surgical resection, with the remaining 6 patients either found to have no abnormalities
on further imaging or were essentially lost to follow up. A postoperative
diagnosis of urethral diverticulum was correctly made in 17 (85%) patients and
vaginal wall cyst was the final diagnosis in 3 patients. Two patients who did
not have physical exam findings underwent surgical resection based on MRI
findings. One was found to have a diverticulum, and the other had no pathology
found at time of surgical exploration (Table 2).Table 1
Patient characteristics.
Mean age (range)42.6 (18–66)No. symptoms (%)Dyspareunia13 (46)Urgency11 (39)Frequency9 (32)Dysuria8 (29)Recurrent urinary tract infection13 (46)Stress  incontinence9 (32)Post void
dribbling5 (18)Table 2
Physical exam
(PE) findings in 24 patients with definitive diagnosis. Definitive diagnosis
was made by either surgery or imaging studies.
Final diagnosis of urethral diverticulumSuspected diverticulum on PEYesNoYes17320No112184Sensitivity (%): 17/18 (94)Specificity (%): 1/4 (25)Positive predictive value (%): 17/20 (85)negative predictive value (%): 1/2 (50).Noninvasive imaging modalities (MRI or
CT) were available for 20 (71%) of the 28 cases reviewed and 19 (95%) of these
patients underwent surgical excision. MRI and CT made the correct diagnosis in
16 (100%) cases with postoperative diagnosis of urethral diverticulum. Three
patients did not have a final diagnosis of urethral diverticulum. Of these, MRI
and CT correctly stated that 2 (67%) were not urethral diverticulum, and
incorrectly stated that 1 (33%) was a urethral diverticulum. The one patient
who did not undergo surgery was diagnosed with urethral trauma based on MRI
findings. In summary, the correct diagnosis of urethral diverticulum (presence
or absence) was made in 19 (95%) patients (Table3).Table 3
Noninvasive imaging
findings in 20 patients.
No033164Sensitivity (%): 16/16 (100)Specificity (%): 3/4 (75)Positive predictive value (%): 16/17 (94)negative predictive value (%): 3/3 (100).In our cohort, videourodynamics
(VCUG) was performed in 11 (39%) patients with symptoms of stress or urge
incontinence. Those with documented Type II stress incontinence (5 patients)
also underwent a pubovaginal sling procedure at time of diverticular resection.
No patient had a diverticulum detected exclusively on VCUG that had not
previously been diagnosed on physical exam. Of note, one patient had a proximal
diverticulum diagnosed by MRI alone, which was not picked up on physical exam
or on VCUG (Figure1).  A total of 8
(30.8%) out of 28 patients had no imaging studies (based on clinical
contraindications like pregnancy), or were lost to follow up (Table 4).Table 4
VCUG in patients with symptoms
of incontinence.
No. of patients with VCUG (%)11 (55)Type II stress
incontinence5 (45)VCUG (+)
diverticula5 (45)MRI/CT (+)
diverticula5 (45)MRI/CT (−)
diverticula0 (0)VCUG (−)
diverticula6 (55)MRI/CT (+)
diverticula6 (55)MRI/CT (−)
diverticula0 (0)Figure 1
Urethral diverticulum on MRI (T2 weighted, fast spin echo). Patient presented with dyspareunia, urinary urgency and a normal physical exam. VCUG showed no evidence of urethral diverticulum. MRI revealed the correct diagnosis.MRI and CT
showed diverticula at an average of 11.1 cm3 (range 0.65–69.8 cm3).
The most common histological finding described by pathology was “chronic inflammation”
in 9 (47%) of 19 patients with surgical pathology available for review.
Nephrogenic adenoma was found in one specimen and in no patient was
diverticular carcinoma found.The average time at the last followup
was 11.9 months (ranging from 0.5–48 months). No
patient (with or without preoperative VCUG) developed de novo urinary
incontinence by history, though postoperative urodynamics testing was not
routinely employed. A single patient had a recurrent urethral diverticula
confirmed by MRI and underwent repeat excision for recurrence 1 year after
initial resection.  This patient had a
large and complex diverticulum with significant proximal extension.


## 4. Discussion

A high index of suspicion is necessary to
initiate the appropriate steps for diagnosis of urethral diverticula. Based
on past studies and reaffirmed in our cohort, once suspected, a good physical
exam can easily and reliably hint at the correct diagnosis; 17 out of 20 (85%)
women were eventually found to have urethral diverticulum based on suspicious physical
exam findings. MRI was diagnostic in one patient in whom physical exam findings
were lacking and who had a proximal diverticulum, and a useful adjunct in
defining diverticular anatomy for surgical planning. As no patient had a diverticula
diagnosed with adjunctive modalities, these are not needed and should not be a
routine component of patient evaluation. Our opinion is that videourodynamics
should be considered only in those patients with concomitant stress
incontinence symptoms or evidence of other genitourinary pathology.Studies from the early 90’s showed
that MRI is sensitive and specific for the detection of urethral diverticulum,
but its high cost and relative unavailability prohibited its use as a
diagnostic tool [11].  Since that time,
improvements in MRI technology and availability have increased its use in the
diagnosis of urethral diverticulum. Daneshgari et al. [8] reported three
cases of intraurethral wall diverticula diagnosed by MRI after cystoscopy,
VCUG, and ultrasonography had failed. Kim et al. examined 20 cases of urethral
diverticula verified surgically, showing that MRI had a sensitivity of 70%, as
compared with urethrography (VCUG and double balloon) or urethroscopy, each with
sensitivity of 55%. Despite these findings, urethroscopy followed by VCUG was
recommended for initial evaluation due to the high cost of MRI at the time of
the study. Five years later, Neitlich et al. [9] reported that MRI could detect
urethral diverticula in women who had negative double-balloon urethrography and VCUG studies. A
T2 weighted, fast spin echo technique was used with a dedicated pelvic
multicoil, creating a faster and more cost-effective technique as compared to
Kim et al. To date, there has been no study directly comparing VCUG with
surface MRI, although Blander et al. [10] retrospectively demonstrated that
endoluminal MRI was more accurate than VCUG in determining size and extent of
urethral diverticula in 27 women.In contrast to these studies, A. C. Wang and C. R. Wang [4] supported the use of VCUG and positive pressure urethrogram in the
diagnosis of urethral diverticula due to their high combined sensitivity of 100%. In their study,
MRI is noted as a better modality overall, but is discounted as a primary
imaging technique due to its high cost. In general, the recent literature
supports the superiority of MRI over invasive imaging modalities by proving its
sensitivity and specificity in detecting urethral pathology, through valid
prospective and retrospective trials [7–10]. Cost
effectiveness is also possible with newer MRI techniques and increased
availability or access to MRI machines, although it is still somewhat of an
issue. In addition, multiple case reports comment on the value of MRI in
elucidating confusing, atypical, or complex presentations. Our contemporary
chart review supports and extends the growing consensus that MRI is the new
gold standard in diverticular diagnosis, as noninvasive imaging modalities made
the correct diagnosis of presence or absence of a urethral diverticulum in 19
out of 20 (95%) patients.Although VCUG has been shown to be
effective in detecting urethral diverticula, inadequate distention of the
urethra or stenotic diverticular ostia can decrease its sensitivity as compared
to other invasive studies [4].  In our
cohort, VCUG added little to the accurate diagnosis and treatment of a urethral
diverticulum. We showed that eliminating this invasive study does not impact on
operative outcomes or diverticular recurrence. However, videourodynamics may
still have a role in the evaluation of patients with urethral diverticula, due
to the high association of concomitant stress incontinence. VCUG would be a
useful study, when surgical treatment for incontinence is desired by the
patient, in addition to diverticular resection [12]. Therefore, both procedures
can be performed at once saving the patient an additional operating room visit.
VCUG may also be useful to evaluate for other genitourinary pathology such as
obstruction (if symptoms warrant) and to help define preoperative voiding dysfunction as
mentioned above.  Otherwise, VCUG is not
a necessary procedure for the routine evaluation of urethral diverticula.It is also unclear if patients with a
diverticulum diagnosed on physical exam need to undergo any imaging study. We
still consider MRI a useful adjunct and advocate its use, especially in
defining the proximal extension of complex diverticula, as seen in our patient
who was diagnosed with MRI alone (Figure1). Currently, it is thought that
patients with significant proximal extension are at an increased risk for
postoperative urinary incontinence. In these cases, high-resolution imaging may
play an important role in preoperative counseling as well as surgical planning.
However with a small, distal, obvious diverticulum seen on physical examination
(in the absence of stress incontinence), proceeding directly to operative
excision is a reasonable, cost-effective approach if MRI is not available.There are some limitations to our
study that deserve mention. As with any retrospective chart review, there is
reviewer dependent bias.
Although our study was relatively large compared to other studies in the
literature, our sample size is still somewhat small. Since charts were pulled
based on diagnosis codes, different physicians performed the physical exam and
VCUG, which creates a chance for variability based on individual skill and
experience.  We are a tertiary care centre,
therefore a few of these patients may have come with a preexisting diagnosis.
This likely produces only a small amount of bias since a large part of our
practice is general urology with many referrals from primary care physicians
within our hospital system. Only three patients in our cohort were referred
from community urologists with a preexisting diagnosis. Different radiologists
read the MRI findings, also creating interoperator variability. The mean size
of diverticula seen on imaging was large (11.1 cm3), which could
play a role in the sensitivity of physical exam.  In addition, not all patients underwent both
VCUG and MRI evaluation, so no direct comparison of imaging modalities is
possible. For future studies, a prospective trial comparing MRI directly with
VCUG is needed to definitively establish which modality has a superior sensitivity
and specificity in the diagnosis and management of urethral diverticula, as
well as overall cost effectiveness.


## 5. Conclusion

Urethral
diverticula can be easily diagnosed on physical exam based on symptoms and
clinical suspicion. MRI can be a useful adjunct for defining diverticular
extent in surgical planning especially in women with proximal diverticula; it
should be the modality of choice if patient presentation is suggestive and
physical exam findings are lacking. Additional invasive imaging, like VCUG, may
still have a role in patients with concomitant urological disease. Otherwise,
VCUG adds little to accurate diagnosis and treatment of urethral diverticula,
and its elimination does not impact accurate diagnosis or operative outcomes.



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