International Journal of Gynecology and Obstetrics 121 (2013) 233–239
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International Journal of Gynecology and Obstetrics
journal homepage: www.elsevier.com/locate/ijgo
CLINICAL ARTICLE
Assessment of levator ani morphology and function in asymptomatic
nulliparous women via static and dynamic magnetic resonance imaging
Xiang-Ran Cai, Lin Qiu, He-Jia Wu, Si-Run Liu ⁎
Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China
1. Introduction
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Keywords:
Levator ani muscle
Levator hiatus
Magnetic resonance imaging
Pelvic floor
Pelvic organ support
Objective: To evaluate levator ani morphology and function in healthy nulliparous women using static and
dynamic magnetic resonance imaging. Methods: Eighty asymptomatic, healthy nulliparous Chinese women
(mean age, 25.3 ± 3.5 years) volunteered for the present study. Static T2-weighted fast spin-echo images
were employed to evaluate levator ani morphology; dynamic T2-weighted fast imaging employing
steady-state acquisition was used to evaluate its function. A 2 samples t test was employed to compare
groups. Results: No morphologic abnormality was detected in the 80 healthy nulliparous women. However,
15% (12/80) of women had various degrees of pelvic organ descent below the pubococcygeal line. In these
women, the width of the pubic portion of the levator ani was significantly reduced during straining, whereas
the levator plate angle, the levator hiatus area, and the H and M line lengths were enlarged. These changes
were associated with weakened levator ani function and pelvic floor laxity. Conclusion: Functional abnormality
of the levator ani muscle was noted in nulliparous women at static and dynamic magnetic resonance imaging.
Further follow-up investigation is needed to confirm whether women with functional abnormality are more
likely to develop a prolapse after vaginal birth.
© 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.
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Article history:
Received 22 November 2012
Received in revised form 15 January 2013
Accepted 21 February 2013
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Pelvic floor dysfunction, which can lead to urinary or fecal incontinence and pelvic organ prolapse, is a common and distressing health
problem in women and affects approximately half of all parous
women above the age of 50 years [1]. It has many complex causes.
Although significant research has been conducted, the mechanism
of pelvic floor dysfunction has not been thoroughly understood, partially because of inadequate knowledge about the anatomy and function of the pelvic floor [2]. Abnormal-appearing levator ani (LA)
muscles with specific dysfunctions were noted in women with pelvic
floor dysfunction [1,3–5].
The LA complex is composed of 5 muscle groups [4,6,7]. It provides key support for the pelvic organs and helps to maintain their
continence. The LA muscles are difficult to assess clinically as they
are hidden in the pelvis. Magnetic resonance imaging (MRI) has
been used since the mid-1980s to image these muscles and to evaluate pelvic floor disorders, owing to its multiplanar capability, superb
soft-tissue contrast, and high temporal resolution [8,9]. The morphology of the LA complex can be shown by static images, and its functional changes upon straining and contraction can be captured by
dynamic images.
⁎ Corresponding author at: Medical Imaging Center, First Affiliated Hospital, Jinan
University, No. 613 West Huangpu Avenue, Tianhe District, Guangzhou City, Guangdong
510630, China. Tel.: +86 13802972821; fax: +86 020 38688416.
E-mail address: tlsr@jnu.edu.cn (S.-R. Liu).
The normal anatomy and function of LA muscles has been studied
in asymptomatic nulliparous women to facilitate understanding of
the muscles’ changes when pelvic floor dysfunction occurs [2,10].
However, it is unclear whether asymptomatic nulliparous women
have normal LA morphology and function. To clarify this issue, the
anatomy and function of LA muscles in a large cohort of healthy
asymptomatic nulliparous Chinese women was investigated using
static and dynamic MRI. This type of information will be useful for objectively identifying the specific structure and functional abnormalities of the LA in symptomatic parous women.
2. Materials and methods
The present study was conducted at the First Affiliated Hospital of
Jinan University in Guangzhou, China, from January 1, 2009, to May
20, 2012. It was approved by the hospital’s Committee for Medical
Ethics and performed in accordance with the principles of the Declaration of Helsinki. Written informed consent was received from all
participants. Eighty healthy nulliparous Chinese volunteers from the
staff and students of the hospital took part in the present study.
Women were excluded if they had had a prior pelvic operation or
had any symptoms of urinary or bowel leakage or pelvic organ prolapse, as identified using a validated questionnaire [11]. Additional
exclusion criteria were any findings such as a pelvic tumor that
might have deformed normal pelvic structures, and an inability to
complete the MRI study.
0020-7292/$ – see front matter © 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.ijgo.2013.01.022
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Magnetic resonance images were obtained in the supine position
by using a 1.5-T unit (Signa Excite; GE Medical Systems, Milwaukee,
WI, USA) with a 4-element torso phased-array coil. The examination
comprised 2 parts. During the first part, detailed evaluation of the
LA muscle anatomy was performed in the axial, coronal, and sagittal
planes using a T2-weighted fast spin-echo sequence (repetition
time/echo time 4000/90 ms; slice thickness/gap 3/0.3 mm; matrix
256 × 204; field of view 20 cm). During the second part, 8 images
in the midsagittal plane of the pelvis were acquired for approximately
10 seconds with the patient in a resting position and during the
Valsalva maneuver in a standardized way using a T2-weighted fast
imaging employing steady-state acquisition sequence (repetition
time/echo time –/1.8 ms; slice thickness/gap 4/0.5 mm; matrix
224 × 256; field of view 38 cm; flip angle 55 degrees). This procedure was repeated with the same sequence in the axial and coronal
planes. Maximal straining was repeated 2 or 3 times to ensure the
reproducibility of maximal effort.
The acquired images were examined using the AW4.2 Workstation
(GE Healthcare, Fairfield, CT, USA). Two radiologists (1 with over
20 years of experience) reviewed the images in consensus; both radiologists were blinded to all clinical and research data.
Image interpretation involved the following measurements. The
iliococcygeal angle (ICA), defined as the angle between the iliococcygeal
(IC) muscle—a horizontal, sheet-like structure that spans the pelvis
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from the arcus tendineus and attaches to the coccyx and anococcygeal
raphe—and the horizontal plane of the pelvis, was measured bilaterally
at rest on 3 representative coronal planes acquired through intermediate sections of the vagina, perineal body, and anal canal, and at maximal
straining on the section obtained through the perineal body (Fig. 1a).
The horizontal plane of the pelvis can be obtained by joining corresponding bony landmarks such as the femoral head or ischial tuberosity
on the pelvic sidewall to correct any pelvic rotation. The IC thickness
(ICT) was measured bilaterally in the center of a coronal plane obtained
through the middle part of the anal canal at rest and on straining
(Fig. 1b). The width of the pubic portion of the LA (LA-P)—composed
of fibers from pubovisceral and puborectal muscles; it laterally inserts
to the pubic symphysis and forms a sling around the rectum—was measured bilaterally on a transverse section in its anterior third at the level
of the inferior border of the pubic symphysis at rest and maximal
straining (Fig. 1c). The levator hiatus area (LHA) was also measured
on the same section (Fig. 1d).
The relative movement between pelvic organs and the pubococcygeal
line (PCL) was analyzed on midsagittal sections (Fig. 2). The PCL,
extending from the inferior part of the pubic symphysis to the
sacrococcygeal joint, was used as the reference line because it represents
the fixation plane of all main support structures of the pelvic floor. The
perpendicular distances from the bladder neck, vaginal vault or uterine
cervix, and pouch of Douglas to the PCL were measured at rest and during
Fig. 1. T2-weighted fast spin-echo images obtained from a woman with normal support at rest, illustrating morphologic measurements obtained in the present study.
(a) Iliococcygeal angle (coronal section obtained through the perineal body). 1 represents the horizontal plane of the pelvis, 2 represents the left IC, and 3 represents the right
IC. (b) Thickness of the left and right iliococcygeal muscle (coronal section obtained through the middle part of the anal canal). 1 represents the thickness of the left IC, and 2 represents the thickness of the right IC. (c) Width of the pubic portion of the levator ani (axial section at the level of the inferior border of the pubic symphysis). 1 represents the width
of the left LA-P, and 2 represents the width of the right LA-P. (d) Levator hiatus area (axial section at the level of the inferior border of the pubic symphysis). Abbreviations: IC,
iliococcygeal muscle; LA-P, pubic portion of the levator ani.
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The LA complex was intact in every woman and no defects were
observed. The IC was clearly visible on the coronal and sagittal planes,
and was found laterally, posteriorly, and superiorly with a cranial
convexity that formed a dome shape on coronal planes at rest. On
maximal straining, it became flattened and the dome shape was
lost. The ICA decreased progressively from anterior to posterior
(Table 2; Fig. 1a,b). The bilateral ICA and ICT at rest were relatively
consistent and showed a tendency to increase from rest to strain in
both groups (Table 3; Fig. 3). The LA-P was medial, inferior, and
formed a sling around the urethra, vagina, and rectum, enclosing
the pelvic hiatus. It was orientated anteroposteriorly with U- or
V-shaped appearance on axial planes. It was markedly thicker than
the IC. The LA-P differed from the IC in that it showed a tendency to
decrease in thickness from rest to strain in both groups (Fig. 4). The
U- or V-shaped pelvic hiatus was seen on axial planes at rest in all
women. During straining, it became slightly enlarged but continued
to keep the same shape in women with normal support. However,
in women with pelvic organ descent it was markedly enlarged and
became O-shaped during straining because the bilateral LA-P bulged
outwardly and caudally (Fig. 4).
The mean bilateral ICA and ICT at rest and during straining did not
show any significant differences between the 2 groups (Table 3).
Among the women with pelvic organ descent, the ICA change from
rest to strain was greater and the ICT change was smaller than
among women with normal support, but the differences were not
significant. The mean width of the LA-P (LA-PW) at rest differed nonsignificantly between the 2 groups. However, the difference during
straining was significant, with the LA-P being narrower in group B
than in group A (Fig. 4). The LA-PW in women with pelvic organ
descent showed a greater change from rest to strain than that in
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straining (Fig. 2a). The H and M lines and the levator plate angle (LPA)
were also measured on the same section. The LPA was defined as the
angle between the levator plate and the horizontal line (Fig. 2b). The H
line was drawn from the inferior part of the pubic symphysis to the
posterior rectal wall at the level of the anorectal junction (Fig. 2a). The
M line was drawn as a line from the posterior aspect of the H line perpendicular to the PCL (Fig. 2a). The lengths of the H and M lines were
then determined.
The mean and standard deviation of the measurements were calculated for all participants. To assess the differences between groups,
SPSS version 16.0A (IBM, Armonk, NY, USA) was used to conduct a 2
samples t test. P b 0.05 was considered to be statistically significant.
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Fig. 2. Midsagittal T2-weighted fast spin-echo images obtained from a woman with normal support at rest, illustrating morphologic measurements obtained in the present study.
(a) Perpendicular distances from the bladder neck, uterine cervix, and pouch of Douglas to the pubococcygeal line; H line (white arrow) and M line (black arrow). (b) Levator plate
angle (black arrow). 1 represents the levator plate angle. Abbreviations: B, bladder; U, uterus; R, rectum.
3. Results
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The examination was well tolerated by all 80 healthy nulliparous
participants. The bladder neck, uterine cervix, and pouch of Douglas
remained above the PCL at rest in all women. However, during maximal straining, pelvic organ descent below the PCL was noted in 12
(15.0%) women. On the basis of these MRI findings, the participants
were divided into 2 groups. For group A (n = 68), the MRI images
acquired during straining showed normal support and no pelvic
organ descent, with bladder neck, uterine cervix, and pouch of Douglas
remaining above the PCL. For group B (n = 12), the respective MRI
images demonstrated lowering of the bladder neck, uterine cervix, or
pouch of Douglas below the PCL. The mean age and body mass index
of the 2 groups were statistically close (Table 1).
Table 1
Characteristics of the study participants (n = 80).a
Parameter
Group A (n = 68)
Group B (n = 12)
P value
Mean age, y
Body mass indexb
Bladder neck descent
Uterine cervix descent
Pouch of Douglas descent
25.1 ± 2.3
20.6 ± 3.2
0
0
0
25.7 ± 1.4
20.3 ± 4.5
12
8
5
0.576
0.545
—
—
—
a
b
Values are given as mean ± SD or number.
Calculated as weight in kilograms divided by the square of height in meters.
Table 2
Left and right iliococcygeal angles on 3 representative coronal sections at rest (n = 80).a
Section
Left iliococcygeal angle
Mean ± SD
Median Range
Vagina section
58.25 ± 6.48 59
Perineal body section 45.51 ± 5.53 50
Anal canal section
33.50 ± 4.27 35
a
Right iliococcygeal angle
Mean ± SD
Median Range
52–66 59.62 ± 5.76 60
37–60 47.13 ± 4.37 51
29–43 34.25 ± 3.96 36
Values are given as degrees.
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50–66
34–61
30–45
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Table 3
Pelvic floor measurements on static and dynamic MRI.
Group A (n = 68)
Mean ± SD
Range
Mean ± SD
Range
0.16–0.61
0.18–0.88
0.00–0.46
0.29 ± 0.02
0.43 ± 0.11
0.15 ± 0.12
0.27–0.34
0.30–0.59
0.01–0.31
0.088
0.386
0.820
0.30 ± 0.10
0.47 ± 0.10
0.20 ± 0.11
0.15–0.55
0.30–0.67
0.00–0.47
0.32 ± 0.05
0.45 ± 0.11
0.15 ± 0.12
0.25–0.38
0.33–0.58
0.00–0.33
0.758
0.667
0.535
46.59 ± 7.66
50.86 ± 6.80
7.48 ± 3.01
30.27–54.56
35.50–56.23
1.25–13.67
44.43 ± 4.50
54.29 ± 4.68
9.86 ± 4.56
38.19–49.27
45.22–58.39
5.30–17.26
0.179
0.114
0.261
47.69 ± 7.59
51.17 ± 8.65
8.41 ± 3.84
32.01–64.39
34.33–68.65
1.06–15.33
46.57 ± 5.68
54.34 ± 4.08
10.42 ± 6.78
37.84–54.17
50.56–62.11
1.29–17.81
0.189
0.135
0.432
0.59 ± 0.20
0.43 ± 0.16
0.16 ± 0.12
0.30–1.13
0.16–0.87
0.03–0.52
0.64 ± 0.20
0.32 ± 0.10
0.30 ± 0.17
0.41–0.94
0.23–0.54
0.09–0.58
0.546
0.010
0.015
0.56 ± 0.21
0.38 ± 0.18
0.17 ± 0.12
0.20–1.09
0.14–0.85
0.02–0.55
0.58 ± 0.16
0.27 ± 0.06
0.34 ± 0.17
0.39–0.78
0.16–0.31
0.09–0.62
0.854
0.001
0.005
46.76 ± 6.85
51.90 ± 6.96
5.83 ± 3.70
32–63
37–67
0–15
46.28 ± 7.30
67.86 ± 7.20
21.57 ± 11.01
60.51 ± 10.74
72.89 ± 15.83
12.85 ± 9.56
35.29–81.61
44.46–109.52
0.72–42.87
4.26 ± 0.83
4.82 ± 0.62
0.59 ± 0.62
1.17–5.34
3.60–6.13
0.01–3.26
1.04 ± 0.37
1.69 ± 0.57
0.65 ± 0.41
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0.33 ± 0.10
0.49 ± 0.14
0.19 ± 0.14
59.29 ± 7.54
118.80 ± 26.67
59.51 ± 31.20
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37–56
61–83
10–42
0.872
b0.001
0.009
48.00–70.16
83.21–158.06
13.05–103.48
0.782
0.003
0.007
3.84–4.85
5.01–7.41
0.80–2.68
0.576
b0.001
0.001
0.40–1.78
0.57–2.99
0.04–1.89
1.26 ± 0.43
3.04 ± 0.52
1.78 ± 0.80
0.65–1.69
2.32–3.66
0.77–2.91
0.174
b0.001
b0.001
1.39–3.10
0.00–2.31
0.17–1.91
1.95 ± 0.54
−0.81 ± 0.20
2.76 ± 0.64
1.45–2.74
−0.48 to −1.13
2.05–4.11
0.645
b0.001
b0.001
1.64 ± 0.56
0.97 ± 0.47
0.67 ± 0.39
0.57–2.89
0.00–1.81
0.12–1.49
1.73 ± 0.29
−0.83 ± 1.34
3.42 ± 0.72
1.48–2.34
−2.19 to 1.31
2.05–4.11
0.545
0.012
b0.001
2.01 ± 0.66
1.52 ± 0.66
0.58 ± 0.44
0.31–3.61
0.28–2.82
0.03–1.44
1.93 ± 0.65
0.19 ± 1.24
2.96 ± 0.97
0.81–2.43
−1.13 to 2.03
1.51–4.44
0.803
0.030
b0.001
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2.06 ± 0.37
1.08 ± 0.66
0.99 ± 0.50
or
4.44 ± 0.35
5.95 ± 0.80
1.50 ± 0.62
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ICT-L, cm
Rest
Strain
Differenceb
ICT-R, cm
Rest
Strain
Differenceb
ICA-L, degree
Rest
Strain
Differenceb
ICA-R, degree
Rest
Strain
Differenceb
LA-PW-L, cm
Rest
Strain
Differenceb
LA-PW-R, cm
Rest
Strain
Differenceb
LPA, degree
Rest
Strain
Differenceb
LHA, cm2
Rest
Strain
Differenceb
H line, cm
Rest
Strain
Differenceb
M line, cm
Rest
Strain
Differenceb
B-PCL, cmc
Rest
Strain
Differenceb
U-PCL, cmc
Rest
Strain
Differenceb
D-PCL, cmc
Rest
Strain
Differenceb
P valuea
Group B (n = 12)
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Abbreviations: B-PCL, distance from bladder neck to PCL; D-PCL, distance from pouch of Douglas to PCL; ICA-L and ICA-R, left and right iliococcygeal angle; ICT-L and ICT-R, left and
right iliococcygeal thickness; LA-PW-L and LA-PW-R, width of the pubic portions of the left and right levator ani muscles; LHA, levator hiatus area; LPA, levator plate angle; MRI,
magnetic resonance imaging; PCL, pubococcygeal line; U-PCL, distance from uterine cervix to PCL.
a
The relatively high P values in the table might be caused by the relatively small number of participants compared with the high number of calculations performed.
b
Difference between rest and strain.
c
Negative values indicate positioning of the bladder neck, uterine cervix, and pouch of Douglas inferior to the PCL; positive values indicate their positioning above the PCL.
women with normal support (Fig. 4) and a statistically significant
difference was noted between the 2 groups.
Measurements of the LPA, LHA, and H and M line lengths at rest
were uniform across the 2 groups. During straining, however, these
values were significantly larger among women with pelvic organ descent than among those with normal support (Fig. 5). The mean
changes from rest to strain in these 4 parameters differed significantly
between the groups.
The distances from the bladder neck, uterine cervix, and pouch
of Douglas to the PCL at rest were similar in both groups (Table 3).
However, a statistically significant difference between the 2 groups
was noted for the values during straining, with group B showing
greater descent than group A.
4. Discussion
In the present study population, static and dynamic MRI of the
pelvic floor provided valuable information about LA morphology
and function in asymptomatic nulliparous Chinese women. This information will be useful for future research that aims to determine
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Fig. 3. Static and dynamic coronal T2-weighted fast imaging employing steady-state acquisition images obtained from 2 women with normal pelvic support, illustrating changes
from rest to strain in iliococcygeal muscle morphology. (a) Iliococcygeal angle at rest. (b) Iliococcygeal angle during straining. (c) Iliococcygeal thickness at rest. (d) Iliococcygeal
thickness during straining. The black arrow signifies the iliococcygeal angle and the white arrow the iliococcygeal muscle.
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whether age and/or vaginal delivery alters LA appearance and function. The PCL was used as a reference line to determine pelvic floor
support in the midsagittal plane. Previous authors placed the posterior
point of the PCL at the tip of the coccyx [5,12–14] or at the last horizontal or vertical joint of the coccyx [1,8,9,15]. In the present study, the posterior point was placed at the sacrococcygeal joint to avoid coccyx
movement affecting the position and length of the PCL, which can
lead to an underestimation of the pelvic organ lift induced by contraction of the pelvic floor muscles [13].
The present results demonstrate that 15% of healthy nulliparous
women had various degrees of pelvic organ descent below the PCL.
However, in each case the descent was mild and did not exceed
3 cm. Many authors [1,7,8] have stated that the bladder neck, pouch
of Douglas, and uterine cervix should remain at or above the PCL
with maximal straining in healthy continent women. Goh et al. [15]
reported that 3 of 25 healthy female volunteers developed a cystocele
and 2 an uterocervical prolapse during strain. In the present study,
the women with pelvic organ descent had significantly larger LPA,
LHA, and H and M line length values during straining than did
women with normal support, highlighting their weakened LA function and pelvic floor laxity. The LPA is considered to be an indicator
of damage to LA muscles [16]. Hsu et al. [16] demonstrated that
women with prolapse had a larger LPA and a larger levator hiatus
length. El Sayed et al. [5] found the levator hiatus width and the ICA
to be important in recognizing pelvic floor laxity. Fielding [1] reported
elongated H and M lines during maximal staining in patients with
pelvic floor laxity. Hence, it is reasonable to conclude that the
women in group B had various degrees of impaired LA function and
pelvic floor laxity. The mechanisms underlying this result are not
clear. In addition to the LA muscle, the pelvic fascia and ligament
also provide support for the female pelvic floor [1,3,17]. Failure in
one element could result in increased demands on other components
[3]. For instance, when fascia and ligament defects occur, this might
place greater pressure on the LA muscle. Thus, the balance of the
whole pelvic floor might be maintained by means of LA functional
changes. When the LA eventually fails as well, pelvic organ prolapse
arises. Further follow-up studies are needed to clarify whether women
with pelvic organ descent during straining will develop pelvic organ prolapse more easily in later life than those with normal support.
During straining, the LA-P and the IC changed in a contrary
fashion. The LA-P became narrower, resulting in an enlarged LHA,
whereas the IC became thicker and flattened owing to the enlarged
ICA and LPA. Li and Guo [18] suggested that the increasing intraabdominal pressure could trigger passive-isometric contractions by
pushing down the LA muscles. Interesting observations were also
made regarding LA-P and IC parameters during rest and straining in
the present study groups. Women with normal support showed a
greater change in ICT and a smaller change in LA-PW from rest to strain
compared with women with pelvic organ descent. Thus, the IC contracts
and provides centrifugal force to the LA-P during straining, and this contraction is stronger in women with normal support. This result is supported by Mørkved et al. [19], who reported significantly higher pelvic
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Fig. 4. Static and dynamic axial T2-weighted fast imaging employing steady-state acquisition images showing the LA-P a woman with pelvic support and a woman with pelvic organ
descent. (a) Woman with normal pelvic support at rest. (b) Woman with normal pelvic support during straining. (c) Woman with pelvic organ descent at rest. (d) Woman with
pelvic organ descent during straining. Abbreviation: LA-P, pubic portion of the levator ani.
Fig. 5. Static and dynamic midsagittal T2-weighted fast imaging employing steady-state acquisition images showing the position of the bladder neck, uterine cervix, and pouch of
Douglas relative to the pubococcygeal line in a woman with pelvic support and a woman with pelvic organ descent. (a) Woman with normal pelvic support at rest. (b) Woman with
normal pelvic support during straining. (c) Woman with pelvic organ descent at rest. (d) Woman with pelvic organ descent during straining. The black arrow signifies the M line;
the white arrow signifies the H line. Abbreviations: B, bladder; R, rectum; U, uterus.
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po
floor muscle strength in continent nulliparous women than in incontinent women and noted that muscle strength and muscle thickness
were strongly correlated.
No LA defects were found in the present study. In a series of 123
nulliparous women suspected of having endometriosis, 56% (n =
69) of patients had at least 1 morphologic change (thinning or
aplasia) in the LA muscles [20]. In another study [21], no LA defects
were identified among 80 nulliparous women, but 20% (32/160) of
the vaginally primiparous women included in this study had LA
defects. Other studies have revealed that LA defects are associated
with vaginal birth [3,21,22] and that women with prolapse often
show LA defects [3].
The present study has several limitations. First, the overall number
and the racial diversity of the participants were limited. Therefore,
the results are not representative of the general population. Second,
the correlation between MRI findings and physical examination
results was not examined. Finally, the interobserver variability of
the present descriptors was not assessed. In an attempt to strengthen
the present study, consensus interpretation by experienced radiologists was used.
In conclusion, the present study investigated the morphology and
function of LA muscles by MRI performed on a series of consecutive
young nulliparous Chinese women. In total, 15% of healthy nulliparous women had abnormal LA function and pelvic floor laxity. Further
follow-up investigation is needed to confirm whether such women
are more likely to develop a prolapse after vaginal birth.
239
Acknowledgments
iza
da
The Medical Research Fund of the First Affiliated Hospital, Jinan
University, China, provided financial support (No. 201207).
Conflict of interest
ut
References
or
The authors have no conflicts of interest.
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aa
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