Susan Robert

M. Ascher, C. Lange,

Uterine Curettage:

MD PhD

Leslie M. Scoutt, MD #{149} Shirley Alan H. DeCherney, MD

#{149}

Changes MR

after Imaging

To determine what, if any, changes occur in the appearance of the uterus on magnetic resonance (MR) images after dilation and curettage (D&C), nine women without endometrial abnormality underwent imaging before D&C and on day 2 and day 7 after D&C. On day 2, markedly hypointense curvilinear areas in the endometrial canal were noted on MR images in all patients (P = .0002). By day 7, these areas decreased in size in five (62%) and completely resolved in the rest (P = .022). There was no significant change in the width of the endometrial stripe or in the width or signal intensity of the junctional zone or myometrium after D&C. The junctional zone was focally disrupted in one patient who underwent D&C that was complicated by a uterine perforation. Therefore, curvilinear areas of low signal intensity (most likely representing clot) in the endometrial canal were visualized on MR images within 2 days of uncomplicated D&C and decreased in size or resolved over time. Significant widening of the endometrial stripe or disruption of the junctional zone was not observed after uncomplicated D&C. Index Uterus, Radiology

I

terms: MR

Uterus, endometrium, 854.45 studies, 854.1214 #{149} Uterus, 854.45 1991;

180:433-435

From the Departments

of Diagnostic

Imag-

ing (S.M.A., L.M.S., S.M.M., R.C.L) and Obstetrics and Gynecology (A.H.D.), Yale University School of Medicine, 333 Cedar St, New Haven, CT 06504. Received December 14, 1990; revision requested January 21, 1991; revision received March 22; accepted April 1. Address reprint requests 0

to L.M.S. RSNA, 1991

M. McCarthy,

MD,

PhD

#{149}

D

Dilation Findings’

and

and curettage (D&C) often precede pelvic magnetic resonance (MR) imaging. For example, in the staging of endometrial cancer, MR imaging is conducted after the diagnosis is established with D&C. Similarly, in benign disorders such as infertility, many women undergo D&C as part of their initial workup. The MR imaging appearance of the uterus after instrumentation, to our knowledge, has not been systematically described. Since it is clearly important that postinstrumentation changes not be misconstrued as disease, we performed a prospective study to evaluate what, if any, changes occur in the appearance of the uterus on MR images after D&C. ILATION

MATERIALS

AND

METHODS

Patients without suspected endometrial abnormality who were undergoing an infertility workup in the reproductive endocrime section and were scheduled for D&C during hysteroscopy were invited to participate in this study. Approval was obtamed from the Human Investigations Committee, and informed consent was obtained from all patients. MR imaging was performed immediately prior to D&C and on the 2nd and 7th days after D&C. Twelve women were enrolled in the study, and a baseline MR image was obtamed. However, three women failed to return for follow-up imaging and were excluded from the analysis. Of the nine patients in the final study group, one failed to return for her day 7 MR imaging examination. The patients were aged 29-43 years (mean, 36.5 years). All women were questioned regarding the presence or absence of vaginal bleeding at the time of MR imaging. The date of the last menstrual period prior to the initial pre-D&C MR imaging examination was recorded in an attempt to estimate the phase of the menstrual cyde at imaging: Four women were in the follicular phase, two were in the secretory phase, and three had irregular cycles or an unknown date of last menstrual period. MR imaging was conducted with a 1.5-T system (Signa; GE Medical Systems, Md-

was localized by with gradient-recalled acquisition in the steady state (GRASS; GE Medical Systems), 25/13 (repetition time [TRJ msec/echo time [TEl msec), ffi angle, 5-mm-thick sections and a 2.5-mm gap, two excitations, 256 x 128 matrix, and a 32-cm field of view. waukee).

means

The uterus of axial images

300

Subsequently, echo [SE]

sagittal

Ti-weighted

(spin

600/’20), intermediate, and T2weighted (SE 2,000(20, 80) images were obtained with 5-mm-thick sections with a 2.5-mm gap, two excitations, 256 x 128 matrix, and a 24-cm field of view. The images were analyzed for the integrity of the zonal architecture of the corpus, and the signal intensities of the endometrium, junctional zone, and myometrium were also tabulated. The widths of the endometrium, junctional zone, and myometrium were measured from the MR images with use of hand-held calipers. The signal intensity of the uterine architecture was qualitatively evaluated relative to the urinary bladder. Homogeneity of signal intensity was also assessed. Statistical analysis of the measurements of the zonal architecture was conducted by means of analysis of variance and the Student t test. Analysis of signal intensity was conducted with the x test. The total number of MR images that were statistically analyzed was 26 (since one patient failed to return for her follow-up examinalion on day 7). Pathologic evaluation of endometrial curettage tissue did not reveal abnormalities. RESULTS The endometrium appeared normal in all nine patients on the pre-D&C MR images: hypointense on the Tiweighted images and hyperintense on the T2-weighted images (isointense to urine). On the T2-weighted images on day 2, however, markedly hypointense curvilinear areas were noted in the high-signal-intensity endometrial stripe in all nine patients

Abbreviations:

spin echo, tion time.

SE

=

D&C = dilation and curettage, TE = echo time, TR = repeti-

433

Figure

1.

(a-c)

weighted

unteer before

MR

Sequential images

sagittal

(SE 2,000/80)

‘

T2in a vol-

before and after D&C. (a) MR image D&C shows a normal endometrial (arrow). (b) MR image 2 days after

stripe

D&C shows (arrow). shows

curvilinear

.

-j

areas of signal void

(c) MR image 7 days that areas of low signal

after D&C intensity have

‘,‘

decreased (arrow). (d) Gradient-echo axial MR image (25/13, 30#{176} flip angle) 2 days after D&C shows area of low signal intensity in the endometrial cavity. No significant blooming

of this

area

r”

K

.

y

is seen.

.

.

-

(100%) after D&C. Among the eight patients who returned for their day 7 post-D&C MR imaging examination (Fig 1), the hypointense areas decreased in size in five women (62.5%) and completely resolved in three (37.5%). At testing for the presence or absence of hypointense areas, the change from before D&C to after D&C was statistically significant (P = .0002). The change from day 2 to day 7 was not significant, whereas the change from baseline to day 7 was significant (P = .022). The gradientecho images also demonstrated markedly hypointense lenticular areas on five of nine images on day 2 that paralleled the findings on the SE images. Of the five patients who had hypointense areas on T2-weighted images on day 7, two also had markedly hypointense areas on gradient-echo images. No significant blooming of these areas on gradient-echo images was noted (Fig 1). The Ti-weighted images demonstrated no change from the preD&C MR images. The entire junctional zone was clearly visualized on the T2-weighted images in seven of nine patients before D&C. After D&C, there was no change in the signal behavior or integrity of the junctional zone on days 2 and 7 with the exception of one patient. In this patient, the junctional zone was focally disrupted on both

a.

b.

C.

d.

days

increase

2 and

7 (Fig

2). Subsequent

view of this patient’s records documented procedure

was

re-

operative that the

complicated

patient’s by

a small

uterine perforation at the site of the disruption noted on MR images. There was no statistically significant change in the width (P = .42) or signal behavior (P = .66) of the myometrium after D&C. The sequential measurements of the components of the zonal architecture are summarized in Table 1. The endometrial stripe averaged 0.84 cm in width before D&C, 0.97 cm on day 2, and 0.80 cm

on

day

creasing on day 434

7. Although

a trend

of in-

endometrial width was seen 2 (Table 2), there was no statisRadiology

#{149}

Table 1 Average Width 2 and 7

Measurements

Obtained

MR Images

from

Widths

Vaginal

Areas

Before 0.84

Endometrium Junctional zone

Note.-Values

tically

are mean

significant

the widths Only one

±

0.56 1.73

Myometrium

(P

±

=

1 standard

.26)

D&C

± ±

in

on

post-D&C MR images (this was the patient who had a uterine perforation at the time statistically

of D&C). significant

width of the junctional after instrumentation.

(cm)

0.97 0.57 1.51

Day 7

0.75 0.32 0.48

± ± ±

0.80±0.46

0.68 1.68

± ±

0.23 0.34

deviation.

change

width

D&C and on Days

Day 2

0.37 0.29 0.23

of the endometrial stripe. patient had a substantial in endometrial

before

There was no change in the zone (P = .55)

D&C. These attributable patients

with

Our study demonstrates that predictable changes can be seen within the endometnal stripe after D&C. Markedly hypointense curvilinear areas occur in patients within 2 days after instrumentation. These hypointense areas either decrease in size or completely resolve within 1 week of

hypointense

noted vaginal MR imaging. hemorrhage signal

not

attributable

bleeding these

over

this,

at the time of parenchymal to change in time

which

(1),

The markedly

passage decrease

by the patients. ings of smaller

decrease bleeding

did

active

of blood

to the

or resolution

hypointense

paralleled the tion of vaginal

we

is probably

to continuous

and

likely since all

areas

bleeding Although is known

behavior

observe

outside.

DISCUSSION

findings are most to bleeding (clot),

of

areas

and/or cessaas reported

Therefore, hypointense

our findareas on

day 7 most likely represented fresh clots that were smaller because endometrial bleeding diminished over time. Air can also cause a signal void.

However,

we do not believe

that August

air 1991

without a mass being noted, discussion of the D&C procedure with the referring physician should clarify whether the D&C was complicated by a uterine perforation. Our study did not address the concurrent occurrence of pathologic condition and blood clots. Others have reported that parenchymal blood clots appear hypointense on T2weighted images and are indistinguishable from endometrial carcinoma (2) or submucosal leiomyomas (3). However, in these studies the age of the clots or initiation of bleeding relative to the MR imaging examinalion was not routinely known or specified, and the magnetic field strengths were 0.5 T (2) or 0.5 T and 1.5 T (3). Hemorrhage has been reported to differ in appearance at different field strengths (4). In any event, our study was limited to the description of uterme changes after D&C and did not aim to pathologically define the underlying cause of the findings. In conclusion, changes in the uterus after uncomplicated D&C are confined to the endometrial stripe and are manifested (at least at 1.5 T) as markedly hypointense curvilinear areas within the endometrial cavity without significant widening of the endometrial stripe. Although MR imaging is optimally performed prior to D&C, the diagnostic value of an MR imaging examination performed soon after D&C should not be adversely affected. U ruption

U.

Figure

2.

uterine

Sequential

perforation.

2 days after and extensive

sagittal

(a) MR image

D&C shows bleeding

Table 2 Endometrial Days 2 and

T2-weighted

images

before

(SE 2,000/20,

D&C shows

loss of integrity in endometrial

normal

Obtained

from

MR

Endometrial

Note.-See * Patient t Patient

No.

Before

patient

architecture.

of the zonal architecture cavity. F = pelvic fluid.

Width Measurements 7 for Each Patient

Patient

80) in the

zonal

at perforation

before

Images

Widths

site

a small (arrow)

D&C and on

(cm)

Day 2

D&C

with

(b) MR image

7

Day

1 2*

0.2 0.8

0.4 0.6

0.6

3

1.0

1.2

4 5 6 7 8t

1.0 0.9 1.0

0.5 0.6 1.1

0.6 1.0

9

...

0.4 1.0

0.8

1.0

0.4

2.8

0.9 1.7

1.5

0.5

0.2

Table 1 for average endometrial widths. failed to return for 7th day follow-up. sustained uterine perforation at D&C

References 1.

was

a significant

contributor

to our

findings because there was no significant blooming of these areas (susceptibility artifact) on the gradient-echo images (Fig id). Also, air would not be expected to be inhomogeneous in signal intensity. The possibility that sloughed endometrium contributed to the described findings cannot be excluded. Our results indicate that changes in the uterus after uncomplicated D&C do not mimic a pathologic condition.

Volume

180

Number

#{149}

2

The study

only

discernible

were

curvilinear

findings

in our

areas within the endometrial stripe. Significant widening of the endometrial stripe, a finding associated with endometnal abnormality (2), was not seen after routine D&C. More important, the junctional zone remained intact after uncomplicated D&C. This is quite relevant to the staging of endometrial cancer based

on

MR

imaging,

2.

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because

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JJ,

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Radiology

#{149} 435