Genitourinary Andrew

Yang,

MD,

MS

#{149} Jacek

L Mostwin,

MD,

PhD

#{149} Neil

B. Rosenshein,

Radiology

MD

#{149} Elias

A. Zerhouni,

MD

Pelvic Floor Descent in Women: Dynamic Evaluation with Fast MR Imaging and Cinematic Display’ The authors present a new method for assessing pelvic prolapse with dynamic fast magnetic resonance (MR) imaging. Twenty-six women with signs and symptoms suggesting pelvic prolapse and 16 control subjects were studied with a series of fast (6-12-second) MR images. Sagittal and coronal images were obtained with graded increase in voluntary pelvic strain, allowing for dynamic display and quantification of the pelvic prolapse process. The distance from the pubococcygeal line was used as an internal reference for measurement of descent in the maximal strain position. With use of control results for normal limit values, prolapse involving the anterior pelvic compartment (cystocele), the middle compartment (vaginal prolapse, uterine prolapse, and enterocele), and the posterior compartment (rectocele) was easily demonstrated. Significant differences between control subjects and patients with prolapse were seen at maximal strain but not in the relaxed state. Quantification of the pelvic descent process with use of fast MR imaging may be of value in surgical planning and postsurgical follow-up.

P

ELVIC

terms: Pelvic viscera, MR studies, 80.1214

prolapse,

85.91

#{149}

1991;

179:25-33

From the Russell H. Morgan Department of Radiology (A.Y., E.A.Z.) and the Departments of Urology (J.L.M.) and Gynecology and Obstetrics (N.B.R.), The Johns Hopkins School of Medicine, Baltimore; and Schultze & Snider & Associates, Union Memorial Hospital, Baltimore (A.Y.). From the 1990 RSNA scientific assembly. Received June 19, 1990; revision requested August 6; revision received December 18; accepted December 26. Address reprint requests to A.Y., 1 106 Gittings Ave. Baltimore, MD 21239. C RSNA, 1991 See also the article by Kruyt et al (pp 159163) in this issue. I

prob-

pelvic floor is mild and not of immediconcern, it may result in

clinical

cases

pain, sociably debilitating stress, total urinary or fecal incontinence, ureterab obstruction, and, in the case of rectal prolapse, constipation and possible rectal ulceration (4). The causes of incontinence and pelvic discomfort are numerous, and the surgeon needs supporting

evidence

to document

pelvic prolapse as the major or contributing cause. The surgical approach to repair depends on precise identification of the pelvic compartments

involved.

examiners.

Existing

methods

of ra-

diobogic evaluation include a series of imaging studies. Bead-chain cystometrography to measure the posterior urethrovesicab angle (5-7), video cystourethrography and cystometrography

with

surement,

sphincter

and

to evaluate

ment,

the

pressure

sonography anterior

vaginography the

middle

mea-

are

is used

barium

pudding

is used

to evaluate Enterocele

used

compart-

to evalu-

compartment,

and

defecography the posterior is not

(8-10) com-

easily

more, ies

three

compartments.

performing

is uncomfortable

Further-

some for

of these the

report

fast

imaging

presents

a new

magnetic in the

method,

resonance

sagittab

(MR)

plane

with

various degrees of pelvic strain, quantification of pelvic descent three compartments. SUBJECTS

AND

for in all

METHODS

Subjects Twenty-six women mean, 56 years) with

(aged 39-86 stress urinary

tinence

symptoms

(5,6)

or other

years; inconsuggest-

ing vaginal or rectal prolapse (10), such as “lump falling down, mass in vaginal introitus with strain, and red lump in rectal area with strain with or without pain and in evacuating

rectum,”

were

re-

ferred for dynamic MR imaging. Sixteen volunteers (aged 27-71 years; mean, 44 years)-women referred for other suspected pelvic pathologic conditions, such as endometriosis or hip pain, but with no history of urinary or fecal incontinence, pelvic organ prolapse, or gynecologic malignancy and no abdominal pain at the time of the study-were imaged as normal control subjects. Informed consent was obtained in all cases. Two of the 16 subjects had undergone Nine of the 26 women

control

tomy.

with

hysterecstress

urinary incontinence or symptoms of prolapse were without a uterus (eight had undergone hysterectomy and in one the uterus was congenitally absent). All but two of the control subjects were parous. Two of the patients were nulliparous.

vi-

sualized without contrast enhancement of the small bowel. None of these studies provide an overall view of all

This

using

difficulty

Physical examination is not always reliable and may be difficult to quantify or not be reproducible between

partment. Radiology

in most

weakness ate

is a common

in older multiparous women, after hysterectomy, with a prevalence of up to 16% (1-

3). While

ate Index Pelvis,

prolapse

lem especially reported

stud-

patients

and some require relatively high radiation exposure from lateral view fluoroscopy and spot radiography. The high rate of failure to ameliorate symptoms and of recurrence of symptoms in each of the three pelvic compartments suggest inadequacies in existing methods of preoperative evaluation (11).

Imaging All

formed

Technique

MR imaging studies were peron 1.5-T units (Signa; GE Medical

Systems, Milwaukee). Routine resting coronal Ti-weighted, axial and sagittal spin-density, and T2-weighted 5-mm-

thick sections fine anatomy

were first obtained and exclude other

to depelvic

disease.

The dynamic in the

sagittal

ent recalled pulse

fast images plane

with

acquisition

sequence

(repetition

were

obtained

use of a gradi-

in a steady time,

state 22-25

msec; echo time, flow compensation; and

13 msec; 30#{176} flip angle; 10-mm-thick section; 256 X 256 matrix and two averages 25

[12

seconds]

or

averages

128

tients,

additional

tamed All

with images

pended

coronal

respiration

untary floor

maneuvers in relaxed

strain, (c) imal pelvic

des gans

(f)

strain

for vol(a) pelvic pelvic

maximal

ability

pelvic The as if you

posi-

strain, (d) maxmaximal pelreproducibility of

to contract and to be reduced

down

supine

instructed

(e) repeat

to assess

pelvic

ob-

pelvic

strain, to ensure

maximal ducibility.

were

as follows: state, (b) mild

effort,

traction

two

pa-

parameters. with sus-

the

were

moderate

strain

and

images

in

The patients

maximal

matrix

In selected

use of the same were obtained

tion.

vic

X 256

[6 seconds]).

conmus-

ability of pelvic voluntarily, and

strain specific

was

perineal of levator

repeated instruction

the are

(g)

for

following:

reprofor

“Bear

constipated

trying to have a bowel that position starting instruction for perineal

or-

and

movement. now.” The contraction

are

Hold specific was

the following: “Squeeze your buttocks together as if you are having diarrhea and did not want to soil yourself. Hold that position

wall

starting with

bulge

now.” pelvic

creasing descent the patient was tions. The study the patients to claustrophobia, data. The in

except

were

then

displayed

1oop

cess. The dynamic imaging minutes to the conventional (including patient instruction In selected patients, the

Dynamic

helpful, ing

in coronal planes bladder base, vagina, not used in image

Patient

plane

shifts

dur-

their

underclothing that

removed,

incontinence were asked to imaging

bladder

full.

to be

half

placed

apart and the knees

The

in a neutral small added

be at the

patients’

slightly

placed Routine

under me-

compression

reduction

legs

position

foam pads comfort.

abdominal

could to void to allow

for

gent (Fig

extending of the line)

from

the

symphysis

was

1). The

to (a) portion

the

used

vertical

most

pubis

to the

joint

(pubococ-

as a reference

distance

bladder floor of the bladder),

inferior

tion

26

cuff, of the

relaxed

Posterior

(16) ± 1.13 ± 1.21 (15) 4.12 ± 1.28 1.88 ± 1.99 (1 1) 2.29 ± 0.99 -0.69 ± 0.83

0.51 1.12

(16) ± ± (20) 0.21 ± -226 ± (6) -0.16 ± -3.98 ±

3.89 2.95

0.72 1.44 0.79 1.44

from

and

Data

line

the

line

(the

most inferior (b) the most infe-

rectal

position

#{149} Radiology

(c)

the

air

was

and

with

most

inferior

measured

maximal

with

were

two use

made

MR imagers of

the

on-line

on

or on hard

internal

one

copies

sence

measurements

of prolapse

partrnents. por-

in

The

the

strain.

were

MR

0.27 -0.87

examination

imaging

the

16 control

to establish the presence

from

a discrimior ab-

in the

The charts

three

pelvic

corn-

of the 26 patients

retrospectively reviewed 6-18 months after MR imaging to see whether prolapse in each compartment was noted

and

on to surgery

cal findings body, bulge

Analysis

patients were used nant value to assess

at physical

went

scale.

tan-

nor portion of the cervix and-in the posthysterectomy patients (n = 1 1)-the vaginal

Middle

1.15 1.24 1.54 1.90 1.07 2.14

mo-

Measurements

of the last coccygeal

cygeal

(16) ± ± (14) 2.05 ± 0.19 ± (12) 1.84 ± -1.88 ±

Subjects

SD by Compartment

Anterior

2.23 1.26

[indicated

in Control

Note-While there is slightly more scatter among the prolapse patients, there was no statistically significant difference between the means of the two groups in the resting position. demonstrating the inadequacy of relaxed images in evaluating pelvic prolapse. However. the differences between control subjects and clinically positive patients were significant in the maximal strain position in each of the three compartments. Values in parentheses are numbers of patients. SD = standard deviation.

of the portion

Position

or Below

was not used.

Analysis

A line

Group

Controlsubjects Relaxed Maximal strain Clinically negative Relaxed Maximal strain Clinically positive Relaxed Maximal strain

maximal voluntary effort, were placed on waterproof

reassured

Image

Mean

strain.

expected. Patients least 2 hours prior

tion

1

and Maximal Strain Positions (in Centimeters Above by -1 Pubococcygeal Line) in the Three Pelvic Compartments and Patients with Suspected Pelvic Prolapse

as the anatomic

with

chanical

Table Resting

not

pads,

were

7

were

ensure patients

and

added about pelvic study time). dynamic se-

images

To the

pelvic pro-

axial

pelvic

1. Sagittal dynamic images of woman with intermittent urinary and fecal incontinence. The relaxed (a) and maximal pelvic strain (b) positions are illustrated. The vertical distance from the pubococcygeal line (PCL) to the bottom of the rectal air (R) in the maximal strain state is 5.5 cm, demonstrating a rectocele. The maximal descent in control subjects with strain was 2.5 cm. Note that with maximal strain, the vertical distances from the bladder base (BB) and the vaginal cuff (VC) to the pubococcygeal line are still within normal limits.

on-

of the prolapse

the

quences were repeated passing through the and rectum but were

b.

Figure

to demonstrate

relationship during

analysis.

a.

in-

for one exclusion due not included in the

a cinematic

the dynamic compartments

abdominal and the

with effort confirm that able to follow the instrucwas well tolerated by all

images

line

The strain

prior

whether

include defective of anterior vaginal

due to cystocele or of posterior vaginal

tocele

or enterocele, of vagina protrusion

or

to dynamic patients

in this period.

strain bulge sion actual

the

urethrocele, wall due

descent

Physi-

perineal wall

with to rec-

or protru-

uterus (procidentia), of rectal mucosa

and (recto-

cele). A patient was considered clinically positive if prolapse in a compartment was noted on a physical examination record. The patient was considered clinically

April

1991

anterior namic

compartment MR imaging

clinically

negative

(Fig showed patients

without cystocele and ically positive patients cele. However, ly negative

went

to be

nine of 12 dinto have cysto-

two of the three and MR-positive

on to undergo

sion

3), dy11 of 14

surgery,

with

clinicalpatients

bladder good

suspen-

results.

The

other patient with negative clinical examination and positive MR results had a history of hysterectomy, abdominal pain, and pain on defecation and demonstrated marked prolapse in all ‘

i.’:p

‘s

-

.-

tT__;\

three

compartments

--

*\

titis

Ms:

c. d. Figure 2. Sagittal dynamic images of postmenopausal woman with stress urinary incontinence and previous incontinence surgery. On relaxed position image (a), pelvic organs bladder (B) and top of vagina (V) are normally related. With mild pelvic strain (b), there is mild anterior bulging of abdominal wall and ing increased intrapelvic pressure. With marked vaginal prolapse are demonstrated.

gans are completely how

the

negative

reduced,

bladder

for

physical tion the

and

floor

rotates

that

compartment

examination findings

record of prolapse

mild descent of bladder and top of vagina, indicatmaximal voluntary strain (c), a large cystocele and With perineal contraction (d), the prolapsed orthe ability of the levator sling to contract is also shown. around the bladder neck.

pelvic

if the did not in that

mencom-

and

strain,

are illustrated.

test.

in Table

1 1 subjects,

measurements

ibility.

The

mean

and

cystica-improved

were

strain

position

ments

in the the

in

each

control

of the

and

correlation

the resting and was calculated

partments

coefficient strain

for each

of the

fers

popula-

Anterior

positions

three

corn-

Volume

Figure 179

2. The #{149} Number

relaxed,

1

three pelvic control subjects

prolapse 3-5. The

pubococcygeal

Posterior

are dis0 line re-

line.

below

images mild

is

strain used

tween

the

line.

limit of descent was the maximal descent

in the control as the discriminant

normal

and

group

abnormal.

and value

MR

imag-

Compartment

did not. The had prolapse at MR

remaining in all three

imaging

(Fig

6).

Compartment no more pubococcygeal

line with maximal strain in the control subjects (Fig 5). Five of six clinicabby positive patients demonstrated rectocele at MR imaging. The other

the bladder more than

pubococcygeal

after

The rectum descended than 2.5 cm below the

We

Compartment strain, descend

months

patients patients

compartments

for the in the

With maximal base should not cm

RESULTS in

tive two

groups in are shown

the lower limit of the control as the discriminant value.

The lower rived from

set of dynamic

and

between

in the two populations.

A typical

cystocele

1.

to the

used group

strain,

compart-

patient

maximal

A large

and patients with played in Figures

deviation

absolute difference between the two measurements were calculated for each of the three compartments. To assess whether the resting position could enable prediction of the maximal

seen

anterior

The vaginal cuff and cervix did not descend more than 1 cm above the pubococcygeal line with maximal strain in the control patients (Fig 4). With use of this criterion, 1 1 of 11 clinically positive patients demonstrated uterine or vaginal prolapse at MR imaging, 13 of 15 clinically nega-

are seen in this patient. and standard deviation

The results compartments

of the

tions,

after

ing-due to an enterocele that had developed in the interim. One patient who was MR negative and clinically positive had a large uterine fibroid and a normal cystometrogram and has not yet been operated on.

Middle

positions

for the control and patient each of the compartments

maximal strain reproduc-

standard

pelvic

contraction

procidentia The mean

made on two consecutive images to assess intrasession

maximal

perineal

partment. Discrepancies between physical examination and dynamic MR results were examined case by case. Differences between means were analyzed by means of a two-tailed Student In

im-

wall suspension. Only one patient who had negative MR but positive clinical examination results eventually underwent surgery-b

Note

at MR

aging. This patient was evaluated by an internist who did not do specific maneuvers to look for pelvic prolapse. One patient who was clinically and MR negative was operated on for metrorrhagia secondary to fibroids. The condition of the other-who had cys-

dewith is be-

In the

1

had a large uterine 20 clinically negative negative MR results

mass. Thirteen patients had for rectocele.

of

However, seven of 20 clinically negative patients demonstrated rectocele at MR imaging, as much as 5.8 cm below the pubococcygeal line. Four of the seven went on to undergo rectocele or enterocele repair. Radiology

#{149} 27

Five patients 7), all of whom Four

of these

had enterocebe were operated enteroceles

4

(Fig on.

were

3

de-

tected on MR images at initial examination. One patient had a defect in the Denonvilliers fascia at static MR imaging enterocebe

only.

Ten

months

later,

an

was demonstrated at physical examination. By MR imaging criteria, there were seven single-compartment prolapses, 1 1 two-compartment prolapses, and four three-compartment prolapses in the 26 patients. prolapse was

In four visualized

patients no on dynamic

We

then

looked

between

the

maximal

strain

was

at the

resting

and

For

0.31 0.59

for the for the

compartment, compartment,

and

0.73

for

the

ment.

In the

lation

coefficient

and

maximal

0.34, 0.68, the three

and

between

prevalence

after

aged

of pelvic

the

resting

was

N-16

in

-6

I

years

had

of vaginal

from

three-fourths

of them

the

were described as having urinary stress incontinence. Only 3% of the 515 desired treatment for their condi-

complaint,

tion, even

bladder

the

problem than the

is pa-

seen at gynecobogic or urobogic In 211 women with pelvic prevalence

of urinary

incontinence was 35% (3). Symptoms of pelvic prolapse indude stress or total urinary or fecal incontinence, urinary retention, constipation, and possible rectal ulcer(4).

Other

28 #{149} Radiology

bess

1

I

I

N-5 I

I

1

N-4 I

I

I

CLINICALLY

CLINICALLY

CLINICALLY

CLINICALLY

NEGATIVE

POSITIVE

POSITIVE

NEGATIVE

NOT

NOT

OPERATED

OPERATED

OPERATED

OPERATED

0.2%

nence,

ation

1

prolapse

ranges

incontinence;

the

I

weakness.

cations include and hemorrhoids The causes

prolapse,

I

Figure 3. Data showing results of resting position (D) and maximum strain () in anterior compartment in control and patient groups. The clinically negative and clinically positive groups (in the anterior compartment) are separated in a. Limits of normal are shown by dashed line. In b, the clinically negative and clinically positive groups are further divided into those who eventually went on to surgery and those who did not. Pubococcygeal line shown by solid line. Vertical scale is in centimeters.

to 43%, depending on the series (2). In an epidemiologic survey, 22% of 515 45-year-old women experienced

tients clinics.

N-i

N-1O

_.___L_ CONTROLS

b.

40-56

suggesting that more widespread

POSITIVE

corre-

the

positions respectively,

floor

hysterectomy

CLINICALLY

NEGATIVE

a.

compartments.

1,349 women

CLINICALLY

was

Pelvic prolapse is a common problem in older multiparous women. Hagstad et al (1) found that 16% of

The

CONTROLS

the

DISCUSSION

evidence

-6

compart-

group,

strain 0.74,

-5

of

the control coefficient

posterior

patient

-3

0.99,

for each

the compartments. group, the correlation

anterior middle

-2

correlation

position

position

0

-4

MR studies. The mean difference between two intrasession measurements of the descent at the maximal strain position was 0.32 cm ± 0.21 in the anterior compartment, 0.32 cm ± 0.25 in the middle compartment, and 0.36 cm ± 0.29 in the posterior compartment. The correlation coefficient (r) between the intrasession test and retest in the three compartments 0.99, and 0.94, respectively.

2

common

compli-

ness

most

associated

The

such bladder,

abnormalities

on

pelvic

compartment(s)

example, be repaired

precise vaginal with

existing

dle-suspension

as unstaand

of the

of therapy

pends

vaginal

intrinsic

abnormalities

choice

weak-

anterior

precise identification The surgical approach

However,

presenting

or attenuation,

or neurogenic

trmnsic

inconti-

anatomic

with

tocebes must be corrected separately. If the problem is a cystocele with anatomic stress incontinence due to a prolapsing bladder neck, the patient may benefit from transabdominal or transurethral urethropexy or a nee-

obstruction

common

include

prolapse ble

ureteral (12,13). of urinary

in-

urethra.

depends on of the cause.

de-

to repair

identification

of the

involved.

For

prolapse alone sacrab cobpopexy.

cystocebes

and

may

rhaphy

rec-

procedure.

Uterine

descent or rectocele alone may be better approached transvaginally, especiably if the patient is frail. The presence of enterocele requires additional repair to close the defect in the Denonvilliers fascia, and preoperative knowledge decreases the chance of accidental bowel damage during posterior colpoperineorThe

(4-6,14).

rates

of failure

and

recurrence April

1991

8

(which ed

prevent

as the

descent)

reason.

are

The

suggest-

frequency

of

6

prolapse

5

age

4

3

caused by the stress of pregnancy and not just that of vaginal delivery

2

alone

1

prevalence tiparous

0

in women

and

rising

That

by

damage

the

-4 -5

also

ligament, bevator applied

-6 -7

predisposes

to vaginal

4.

floor

did

not

prolapse. 3

is supportbroad ligauterosacral

pubocervicab ligament, and muscles. Yet, Mengert (17) traction to the cervix of caand sequentially severed each

davers of the potential tures. Surprisingly,

-8

is

increased

prolapse (11). The uterus ed by the round ligament, ment, paravaginal tissue,

-3

with

of prolapse among mulwomen who deliver by of cesarean section (16). Hys-

terectomy

-2

parity.

is suggested

means

-1

increases

pelvic

support an intact

interfere

with

However,

pelvic

severance

2

parametrial or paravaginal suIts in immediate descent.

0

With the the literature mechanism

chose

strucpelvic of the tissue

present uncertainty regarding the of pelvic support,

to measure

interaction

the

of the

net

rein

exact we

result

support

of the

structures

rather than the individual candidates for pelvic support. We chose the pubococcygeal line because it is easily measured and independent of the

-2 -3 -4

pelvic

-5

tilt

of the

patient.

Also,

com-

ponents of the pelvic floor, such as the pubococcygeab muscle, puborectal muscle, and pubovesical ligament, attach along this line. Thus, there is

-6 -7

-8

some theoretical line as a reference

CLINICALLY NEGATIVE

5.

basis for

for the

using pelvic

this

floor.

Figures

4, 5. Data showing results of resting position (D) and maximum strain (0) in middle (4) and posterior (5) compartments in control and patient groups. The patient group is divided into clinically positive and clinically negative sets. Limits of normal as derived from the control data are shown by dashed line. Pubococcygeal line shown by solid line. Vertical scale is in centimeters.

The

mechanism underlying stress incontinence is controversial. It is generally believed that intraabdominal pressure is transmitted

urinary

equally through the bladder and urethral neck as long as both are above the

after surgery for prolapse suggest inadequacies in existing preoperative evaluation (1 1). For example, of 236 patients reevaluated 1 year after vaginab or suprapubic continence surgery, only 70.6% considered themselves cured (15). In our series of 26 patients, eight had undergone unsuccessful incontinence or prolapse surgery. In many cases, physical examination by an experienced physician can determine

the

pelvic

compartment

involved, as seen by the high correlation between clinical and MR identification of prolapse in our patients. It is difficult to give accuracy data when physical examination is an imperfect standard of reference. However,

Volume

in our 179

small

study,

#{149} Number

MR

1

provid-

ed

additional

therapy the

information

regarding

anterior

tients, in the two patients, compartment experienced the compartments

particular lapse

pelvic

related

in other

MR

tative

and

prolapse

simultaneous

and

follow-up

the

allows

prolapse

is of

in

represents

levator

in men, muscles

and

the

or pubovesical

This

is a linear

pubourethrab

ligament

is unclear (20-22). But, with use of this structure, the anatomic descent of the bladder neck (rather than bladder

floor) is rare

images.

an intrinsic neck that was of the sagittal

structure of low signal intensity that extends from the inferior border of the symphysis pubis to the vesicourethral junction (Fig 8). Whether this

of

This

examina(eg,

nence (18,19). We have marker for the bladder well seen in about 50%

dynamic

postoperative

when physical are equivocal

prominent

travesical pressure overcomes urethral pressure, resulting in inconti-

quanti-

analysis

tion results obese patients).

Pelvic

bococcygeal

pro-

all three pelvic compartments. useful in objective documentation

neck (puin-

in

Dy-

provides

floor. As the bladder below the pelvic floor line), the unopposed

pa-

to their

overlook

compartments.

imaging

and

in two

middle compartment in and in the posterior in four patients. Less physicians may focus on

specialty

namic

descent

compartment

pelvic

descends

affecting

may

ligament

be measured.

toceles,

the

bladder

floor

rotational

may

In large descent

bring

cys-

of the

it substanRadiology

#{149} 29

lL.’i

tially inferior to the bladder neck (Fig 2). Whether the loss of abdominal pressure transmission to the blad-

der

or kinking

of the

urethra

ms ,

#{149}.% .

:sb

There

‘

l#{149}

plains the paradoxical lack of incontinence in some of these patients is unclear. Yet, if the patient has marked discomfort, surgical repair or placement of a pessary may still be required.

‘

,

.4fr

no statistically signifiat the resting position between the control, clinically negative, and clinically positive groups in each of the three compartments. This cant

L..

‘.

ex-

.

.

was

difference

suggests that the dynamic

static images

to differentiate

greater

patient

b.

popula-

tested whether position will

prolapse

a.

images without are insufficient

the

tions. We then tial low resting

-.

in each

mi-

an result

of the

in

three

compartments. However, the correlation was low between the positions of the bladder, cervix or vaginal cuff, and rectum at rest and the positions

at maximal

strain.

This

suggests

that

resting position does not allow prediction of the maximum prolapse position well. Other parameters that can be mea-

sured dude

on the spin-echo images inthe thickness of the muscles

composing

the

length

of the

pelvic

ness and integrity muscle ring. On

echo

images,

ethral

angle

bead-chain anorectal

the

and

the

dynamic

vesicour-

measured

on

cystometrograms angle (5-8) measured (Fig

9) can

measurements extent that,

curving be drawn

be

and

6. Relaxed sagittal (a) and coronal (c) and maximal strength sagittal (b) and coronal images in patient with prolapse in all three compartments. The coronal images were taken through the middle compartment. With strain, the levator muscle sling (arrow) is stretched by the prolapsing vagina. The left and right distance between the muscles also increases. However, compared with the horizontal resting position of the muscle, the levator appears more vertically oriented and is more parallel to the direction of the prolapse. It is possible that a larger vector of muscle force is in the direction of the prolapse. Coronal images may be useful in assessing levator function. B bladder, V vagina.

the on

estimated.

are subjecfor a continu-

structure, at several

the tangents locations,

depending and rectal

on the distention,

degree of bladder respectively.

However,

at least

the

free of the projectional cation errors inherent ray cystometrograms grams.

Figure

(d)

gradient-

posterior

(5,6,14)

These two tive to the

thick-

of the periurethral

the

defecograms

ously may

floor,

urethra,

MR

images

are

and magnifiin routine xand defeco-

mesenteric or retroperitoneal fat that is often present in this defect, even on relaxed images. During maximal

try

pelvic

strain,

od,

herniate ing an

through enterocele

enterocele ing

Other anatomic causes of incontinence, such as a scarred, low-compliance urethra or fistulas, can coexist with pelvic prolapse, and the radiologist should search for them on the spin-echo images. An important advantage of dynam-

the

the

this (Fig

is not stress

small

bowel

may

defect, produc7b). Even if an

demonstrated

images,

the

durreferring

surgeon should be alerted to the defect because of the potential for future herniation or the potential presence of a low-lying bowel ioop that may be damaged by cautery during

posterior

vaginal

repair.

nective tissue between the posterior wall of the vagina and the anterior wall of the rectum (4,23) (Fig 7a).

Precise instructions for the patient are important to ensure that the correct maneuvers are used. We use permeal contraction to document that the patient understands the concept of pelvic relaxation and strain. We always instruct the patient to repeat the maximum pelvic strain to ensure reproducibility of maximal effort. We

This

continue

ic MR imaging the visualization

of pelvic prolapse of enteroceles.

lowing hysterectomy, exist in the rectovaginal the

Denonvilliers

defect

30 #{149} Radiology

a defect may septum or

fascia,

is visible

is Fol-

a loose

because

con-

of the

to encourage

the

patient

to

harder

until

position

the

appears

ly four the

ibility

maximal

strain

reproducible,

to six times. mean

usual-

With

this

intrasession

meth-

reproduc-

was 0.32, 0.32, and

0.36 cm, re-

spectively, in the three pelvic compartments. Differences in descent below 0.5 cm are probably within measurement imprecision. We do not yet have enough data for long-term intersession reproducibility. The Valsalva maneuver is not identical to pelvic strain in that penneal contraction can take place simultaneously with the Valsalva maneu-

yen. and the the

We use

graded

pelvic

strain

steps

observation of the slight bulge of abdominal wall and descent of pelvis to confirm effort and com-

pliance

with

the

overdistended prolapse.

should

ceeding

instructions.

bladder In

be

such

asked

with

the

a case,

An

may the

to void

prior

study.

The

prevent patient

to pro-

postApril

1991

I

Figure

7. (a) Five-millimeter-thick (left) and axial (right) Ti-weighted echo images (repetition time, time, 20 msec) showing fat (F) in the Denonvilliers fascia or septum. (b) Sagittal (top) and

sagittal spin600 msec; echo in the defect rectovaginal coronal (bot-

tom) fast images of same patient as in a. With maximal strain, the poised small bowel loop herniates through the defect (D) in the Denonvilliers fascia to produce a large enterocele (E). With perineal contraction, the enterocele is reduced. Note that there is no cystocele. Elongated cervix (EC) is seen in chronic prolapse. Note increase in transverse diameter (TD) of the pelvic floor with strain. B = bladder, C = cervix, DF degenerating fibroids, LM levator muscle, PM puborectal muscle, R rectum, SB small bowel, U = uterus.

may

underestimate

the

extent

of nec-

tab descent

if there is no rectal air at all. It is possible to mark the anal verge with contrast material such as gadopentetate dimeglumine used with dilution or baby oil. The overestimation of rectal air due to susceptibility was small, on the order of 1-3

mm, and may be reduced by increasing the flip angle or using newer partial-Fourier spin-echo pulse sequences. sualized, na (hence sometimes

there

While the cervix is well vithe lower limit of the vagithe vaginal length) is not measurable. When

is a question

of the

vaginal

as to the

location

or cervix,

we

cuff

use

the static spin-echo images to confirm the anatomy. The pressure causing the pelvic prolapse process in the supine position is limited by voluntary

effort

and

dominal

the

strength

musculature

derestimated the upright

compared position.

adequate

data

of the

and

on the

We

may

with do

effect

ab-

be un-

that in not have

of parity,

as there was a mixture of live vaginal deliveries, miscarriages, cesarean sections, and hysterectomies in our study and our numbers were too small to be specific. Furthermore, we did not have enough control subjects to derive age- or parity-specific normal limits of pelvic descent. Our present suggestions for indications for dynamic MR imaging of pelvic prolapse are shown in Table 2. Additional indications may evolve as urologists and gynecologists are introduced to this new imaging meth-

b.

od. The voiding

residual

ed as well. and maximal

are used steps

temporal during There

Volume

volume

is then

While only the strain sagittal

in data

allow

the graded display of the relationships

spatial

the prolapse are some

179

resting images

analysis,

cinematic

and

not-

process. potential

#{149} Number

1

improvement technique. We have further

tamed simultaneous measurements of intraabdominal or intravesical pressure and cannot measure urodynamic parameters such as detrusor

instability. areas

for

in this imaging not as yet ob-

rectum

The amount is variable,

and

of air in the this

technique

quantitative

vic prolapse with clinical

of surgery,

evidence

should data

of pel-

be integrated to decide what

if any,

type

is indicated.

CONCLUSION We have invasive

developed method

a simple

to quantify

nonsimulta-

Radiology

#{149} 31

neously pelvic

MR od

pelvic

prolapse

compartments

imaging. so that

in all three with

use

of fast

the

meth-

We designed it may

mented on most with commerdially

be

easily

imple-

clinical MR available

imagers fast

pulse sequences. The limits of normal descent with maximal strain are 1 .0 cm below the pubococcygeal line for the bladder base, 1 .0 cm above for the vaginal cuff or lower end of the cervix, and 2.5 cm below for the redtal air. Preliminary results suggest this method will augment and possi-

bly

replace

methods common

some in the clinical

existing evaluation problem.

imaging of this U

Acknowledgments: We thank Renate Soulen, MD, Renee Genadry, MD, Marc Pessar, MD, Robert McLellan, MD, and Shirley Yang, MD, for encouragement and MR imaging technologists Kathy Lipinski, RT, Robin Franz, RT, Clark Pool, BA, RT, Wen Liu, RT, Mary Lally, RT, Keith Penn, RT, Cheryl Moser, RT, Laura Prevost, RT, and Hugh Wall, RT, for their good-humored patience and technical assistance.

References 1.

2.

3.

4.

5.

6.

7.

32

Hagstad A. Janson P0, Lindstedt G. Gynaecological history, complaints, and examinations in a middle-aged population. Maturitas 1985; 7(2):115-128. Cruikshank SH. Preventing posthysterectomy vaginal vault prolapse and enterocele during vaginal hysterectomy. Am Obstet Gynecol 1987; 156:1433-1440. H#{216}rding U, Pedersen KH, Sidenius K, Hedegaard L. Urinary incontinence in 45year-old women: an epidemiological survey. Scand J Urol Nephrol 1986; 20:183186. Zacharin RF. Pelvic floor anatomy and the surgery of pulsion enteroceles. Vienna: Springer-Verlag, 1985. Green TH. Urinary stress incontinence: pathophysiology, diagnosis and classification. In: Buchsbaum HJ, Schmidt JD, eds. Gynecologic and obstetric urology. Philadelphia: Saunders, 1982; 199-224. Raz S. Evaluation of urinary incontinence. In: Buchsbaum HJ, Schmidt JD, eds. Gynecologic and obstetric urology. Philadelphia: Saunders, 1982; 225-238. McGuire E. Causes of involuntary unnary loss and ways to recognize them. In: McGuire E, ed. Urinary incontinence. Or-

#{149} Radiology

the ages. With

portion of the symphysis pubis (P) to the the vesicourethal junction on the relatively Relaxed image is on the left and maximal strain maximal strain, the bladder base (arrow) descends

inferior

marker

for

Table 2 Current Suggestions

for Dynamic

MR Imaging

vesicourethral junction and provides low-contrast gradient recalled imimage is on the right. B bladder. below the vesicourethral junction.

Evaluation

1. Patients with incontinence or other symptoms of prolapse but study or physical examination results Postoperative patients with recurrence of incontinence or prolapse Serial follow-up of patients conservatively treated to document Patients with suspected enterocele or multicompartment prolapse Patients unable to tolerate contrast media or available radiographic of prolapse 6. Older children or young adults with imperforate anus. prior anatomy and to demonstrate ability of levator muscles to contract 7. As a research tool to investigate biomechanics of pelvic prolapse based on the findings

2. 3. 4. 5.

of Pelvic with

equivocal

a

Descent urodynamic

improvement procedures

for evaluation

to reconstruction, and

to design

to define new

therapies

April

1991

8.

9.

10.

11.

12.

13.

4

14.

15.

a.

16.

ri

17.

18.

19.

11

20.

.

21.

22.

23.

Figure gram

9.

Estimation

(a) and

MR imaging. in a and

between

Volume

179

of posterior

anorectal

Note

angle

change penineal

#{149} Number

measured

vesicourethral angle on defecogram

in the two angles contraction

1

and

between maximal

measured (b) with

relaxed strain

on use

and

positions

bead-chain of noninvasive

maximum

strain

Whitehead WE, Schuster MM. Anorectal physiology and pathophysiology. Am Gastroenterol 1987; 82:487-497. Mahieu P, Pringot J, Bodart P. Defecography. I. Description of a new procedure and results in normal patients. Gastrointest Radiol 1984; 9:247-251. Mahieu P. Pringot J, Bodart P. Defecography. II. Contribution to the diagnosis of defecation disorders. Gastrointest Radiol 1984; 9:253-261. Morley GW, Delancey JD. Sacrospinous ligament fixation for eversion of the vagina. Am J Obstet Gynecol 1988; 158:872881. Delaere K, Moonen W, Debruyne F, Jansen T. Hydronephrosis caused by cystocele: treatment by colpopexy to sacral promontory. Urology 1984; 24:364-365. Heslop JH. Piles and rectoceles. Aust N Z J Surg 1987; 57:935-938. Blaivas JG, Olsson CA. Stress incontinence: classification and surgical approach. J Urol 1988; 139:727-731. Stocklin MW, Alder CG. Subjective and objective improvement of urinary incontinence in females following vaginal and abdominal incontinence operations. Geburtshilfe Frauenheilkd 1986; 46:524-529. Taylor RW. Pregnancy after pelvic floor repair. Am J Obstet Gynecol 1966; 94:3539. Mengert WF. Mechanics of uterine support and position. Am J Obstet Gynecol 1936; 31:775-782. Enhorning G. Simultaneous recording of intravesical and intraurethral pressure. Acta Chir Scand 1961; 276(suppl):1-68. Jeffcoat TN, Roberts H. Observation on stress incontinence of urine. Am J Obstet Gynecol 1952; 64:721. Lierse W. Applied anatomy of the pelvis. Berlin: Springer-Verlag, 1984; 74-75, 148149. Pernkopf E. Atlas of topographic and applied human anatomy. Vol 2. Baltimore: Urban & Schwarzenberg, 1980; 337. Delancey JOL. Pubovesical ligament: a separate structure from urethral support (“pubo-urethral ligaments”). Neurourol Urodynamics 1989; 8:53-61. Kuhn RJ, Hollyock yE. Observations on the anatomy of the rectovaginal pouch and septum. Obstet Gynecol 1982; 59:445447.

cystometrodynamic

positions

in b.

Radiology

#{149} 33