(Radiographics. 1999;19:927-935.)
© RSNA, 1999
Focal Intracavitary Masses Recognized with the Hyperechoic Line Sign at Endovaginal US and Characterized with Hysterosonography1
Matthew T. Baldwin, MD ,
Kika M. Dudiak, MD ,
Brian Gorman, MB, BCh and
Catherine A. Marks, MD
1 From the Department of Radiology, Mayo Medical Center, 200 First St SW, Rochester, MN 55905. Recipient of a Certificate of Merit award for a scientific exhibit at the 1997 RSNA scientific assembly. Received April 9, 1998; revision requested June 11 and received September 8; accepted September 8. Address reprint requests to K.M.D.
 |
Abstract
|
|---|
In 42 women, endovaginal ultrasonography (US) was performed because of an abnormal central endometrial complex. Retrospective review of the endovaginal US scans and subsequently obtained hysterosonograms with histopathologic correlation showed a hyperechoic line surrounding the central endometrial complex in 25 patients, all of whom had focal intracavitary processes. Cystic spaces within the central endometrial complex in 17 of these patients reflected polyps; this finding was associated with a hyperechoic line in 15. At hysterosonography, all polyps (n = 29) had a narrow attachment to the endometrium. All five fibroids were broadly attached and had a rim of overlying endometrium. These focal abnormalities were easily distinguished from global endometrial processes amenable to a blind biopsy procedure. This initial experience showed that a hyperechoic line circumscribing the central endometrial complex at endovaginal US allows prediction of focal intracavitary disease, particularly when the line is associated with cystic spaces within the central endometrial complex. The presence of a hyperechoic line can be used to direct the patient to a visually guided hysteroscopic procedure rather than a potentially unsuccessful blind biopsy procedure. Alternatively, absence of a hyperechoic line can prompt management appropriately directed by hysterosonographic characterization of the uterine contents as focal or diffuse.
Index Terms: Uterine neoplasms, diagnosis, 854.30 • Uterine neoplasms, US, 854.12989, 854.30 • Uterus, US, 854.12989
|
INTRODUCTION
|
|---|
A thickened endometrium at endovaginal ultrasonography (US) is a reliable predictor of endometrial disease (1,2). Although this sign is sensitive, the nonspecific nature of the thickening has led most gynecologists to use tissue-specific techniques such as blind endometrial biopsy or dilation and curettage as the initial screening method for endometrial disease. Unfortunately, both of these methods are unguided and inexact. They are better suited to assessment of global endometrial processes: With endometrial biopsy, uninvolved portions of the endometrium may be randomly sampled and focal intracavitary masses such as polyps may be skipped (3,4); with dilation and curettage, focal lesions may also be missed and only 60% of the surface of the endometrial cavity may actually be sampled (5). In contrast, hysteroscopy is a very sensitive tool for surveying the endometrium (6–8), but its expensive and somewhat invasive nature precludes its routine use in screening for endometrial disease. It seems logical to reserve hysteroscopy for diagnosis or treatment of known focal intracavitary processes, a situation ill suited to diagnosis with blind sampling techniques.
Hysterosonography can provide more specificity in distinguishing between various intrauterine processes than can endovaginal US or endometrial biopsy (4,9,10). Although hysterosonography better demonstrates the contents of the endometrial cavity, it is not available at all institutions. In our practice, use of hysterosonography has allowed us to retrospectively recognize a specific pattern on endovaginal US scans that occurs with focal processes. This pattern consists of a hyperechoic line partially or completely surrounding the central endometrial complex (Fig 1). The line can be seen with many focal intracavitary processes including polyps, submucosal fibroids, foci of asymmetric hyperplasia, and localized neoplasia. All of these focal processes are best managed with hysteroscopy, which allows direct visualization for inspection and subsequent biopsy of intrauterine disease.
View larger version (140K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1a. Hyperechoic line sign. (a) Longitudinal endovaginal US scan shows a focal mass. There is a hyperechoic line (arrows) partially surrounding a thickened central endometrial complex. An underlying polyp was demonstrated with hysterosonography. (b) Drawing shows the hyperechoic line surrounding the thickened central endometrial complex.
|
|
View larger version (31K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1b. Hyperechoic line sign. (a) Longitudinal endovaginal US scan shows a focal mass. There is a hyperechoic line (arrows) partially surrounding a thickened central endometrial complex. An underlying polyp was demonstrated with hysterosonography. (b) Drawing shows the hyperechoic line surrounding the thickened central endometrial complex.
|
|
In this article, we propose an algorithmic approach to investigating a thickened or distorted endometrium at US. Patients with a recognizable focal mass at initial endovaginal US, a finding characterized by a hyperechoic line, can be easily triaged to hysteroscopy. Hysterosonography should be reserved for cases without specific evidence of a discrete process at endovaginal US. We also present the typical features evident at hysterosonography that enable the radiologist to characterize various focal masses and to distinguish them from diffuse endometrial processes.
|
METHODS
|
|---|
Hysterosonography was performed in 42 pre- or postmenopausal women with an abnormally thickened (1,2), distorted, or indistinct endometrium at initial endovaginal US. The endovaginal US scans and companion hysterosonograms were retrospectively reviewed and correlated with histopathologic data. Follow-up was performed as follows: Eighteen patients underwent hysteroscopy with guided biopsy, 11 underwent dilation and curettage, six underwent blind endometrial biopsy, and six underwent hysterectomy. One patient was evaluated with magnetic resonance (MR) imaging with the findings considered to be diagnostic of a uterine fibroid.
To perform hysterosonography, we find it helpful to store all of the necessary materials in a single mobile cart. The patient is placed in the lithotomy position on a dedicated bench with stirrups. The cervix is exposed with a speculum and gently cleansed with Betadine (povidone-iodine; Purdue Frederick, Norwalk, Conn) swabs extended on a ring forceps. A 5.3-F insemination catheter (Cook Urological, Spencer, Ind) or, in difficult cases, a 5-F balloon-tipped catheter (Ackrad Laboratories, Cranford, NJ) is advanced through the mouth of the cervix into the uterine cavity. The speculum is exchanged for an endovaginal ultrasound probe (Acuson, Mountain View, Calif) without disturbing the catheter position (Fig 2). Sterile saline solution is introduced through the catheter under direct US guidance until adequate uterine distention has been achieved. Representative transverse and longitudinal images are obtained.
View larger version (64K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2a. Two sequential technical steps necessary to performing hysterosonography. (a) Drawing shows introduction of a catheter into the endometrial cavity with the aid of a long-ringed forceps. (b) Drawing shows replacement of the speculum by an endovaginal probe and distention of the uterine cavity with sterile saline solution.
|
|
View larger version (58K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2b. Two sequential technical steps necessary to performing hysterosonography. (a) Drawing shows introduction of a catheter into the endometrial cavity with the aid of a long-ringed forceps. (b) Drawing shows replacement of the speculum by an endovaginal probe and distention of the uterine cavity with sterile saline solution.
|
|
The attachment and internal characteristics of a visible focal process are routinely documented with gray-scale and color Doppler imaging. The thickness of a more global endometrial process is recorded.
|
ALGORITHM AND CLINICAL EXPERIENCE
|
|---|
We propose an imaging algorithm for diagnosis and management of endometrial disease. The algorithm is based on the premise that focal processes should be directed to hysteroscopy rather than to blind endometrial biopsy. When features of a focal endometrial process are recognized at initial endovaginal US, no further imaging is necessary; instead, hysteroscopy is recommended (Fig 3). This approach allows hysterosonography to be used only selectively in cases in which the distinction between focal and diffuse disease cannot be reliably made at initial endovaginal US. Evidence of a focal mass at hysterosonography would also warrant hysteroscopy. Only patients with documented diffuse processes at hysterosonography would remain suitable candidates for blind endometrial biopsy.
View larger version (24K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3. Diagram shows the proposed algorithm for diagnosis and management of endometrial disease. CEC = central endometrial complex, D&C = dilation and curettage, EMB = endometrial biopsy, MRI = MR imaging, TVS = transvaginal (endovaginal) US.
|
|
Fibroids have a characteristic appearance at MR imaging (11). The algorithm could be expanded to include MR imaging as a means of identifying submucosal fibroids and further distinguishing them from other focal processes when a focal mass is evident at initial endovaginal US or companion hysterosonography.
Endovaginal US
Focal Process (Hyperechoic Line).—When a thickened or distorted endometrium is seen at endovaginal US, characteristics of a focal mass or process may be present. These include a hyperechoic line surrounding the central endometrial complex or cystic spaces within the central endometrial complex. Recognition of a hyperechoic line, cystic spaces, or both at endovaginal US may indicate that a focal mass is present and that hysterosonographic evaluation is not necessary.
We believe that this hyperechoic line represents (a) the interface between the focal lesion and the endometrial lining or (b) the thin endometrium itself. The line may be seen when any mass abuts the endometrium. All 25 patients in our series with a hyperechoic line surrounding part or all of the central endometrial complex at endovaginal US had a focal intracavitary process: Twenty-three had polyps, one had a submucosal fibroid, and one had an area of focal endometrial thickening (Table). None of the patients with a hyperechoic line had a diffuse endometrial process. According to the proposed algorithm, these patients should be directed to hysteroscopy. Further scrutiny of the central endometrial complex can reveal additional evidence of a focal mass at initial endovaginal US. We have observed that a focal endometrial process may be better characterized when cystic spaces are present within the central endometrial complex in company with a hyperechoic line.
A hyperechoic line can occur in conjunction with cystic spaces in the central endometrial complex (Fig 4). These cystic spaces may reflect cystically dilated glands in an underlying polyp and can provide more specificity when present on the endovaginal images. All 17 patients with cystic changes in the endometrium at endovaginal US had polyps; 15 of them also had a hyperechoic line surrounding the central endometrial complex. Only two patients had isolated cystic spaces within the central endometrial complex with no visible associated hyperechoic line.
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4a. Hyperechoic line related to an underlying endometrial polyp. (a) Transverse endovaginal US scan shows a hyperechoic line surrounding the central endometrial complex (arrowheads). There are also cystic spaces within the central endometrial complex (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows an endometrial polyp (arrow) with a narrow attachment to the endometrium (arrowheads).
|
|
View larger version (151K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4b. Hyperechoic line related to an underlying endometrial polyp. (a) Transverse endovaginal US scan shows a hyperechoic line surrounding the central endometrial complex (arrowheads). There are also cystic spaces within the central endometrial complex (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows an endometrial polyp (arrow) with a narrow attachment to the endometrium (arrowheads).
|
|
A focal mass may manifest as a thickened endometrium with a surrounding hyperechoic line at endovaginal US in the absence of associated internal cystic changes (Fig 5). Although this pattern is less specific, in our experience, it still occurs most commonly with endometrial polyps. It is also seen with submucosal or intracavitary fibroids, focal areas of endometrial thickening, and focal carcinoma. Ten of 25 patients with a hyperechoic line surrounding the central endometrial complex at endovaginal US lacked internal cystic spaces: Eight had polyps, one had a submucosal fibroid, and one had an area of focal hyperplasia.
View larger version (127K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5a. Hyperechoic line related to an underlying submucosal fibroid. (a) Transverse endovaginal US scan shows a hyperechoic line partially surrounding a thickened central endometrial complex with a bland internal architecture (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows a submucosal fibroid with a large intracavitary component (arrow). (c) Sagittal T2-weighted MR image shows the large intracavitary component of the fibroid (arrowhead), which is hypointense.
|
|
View larger version (124K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5b. Hyperechoic line related to an underlying submucosal fibroid. (a) Transverse endovaginal US scan shows a hyperechoic line partially surrounding a thickened central endometrial complex with a bland internal architecture (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows a submucosal fibroid with a large intracavitary component (arrow). (c) Sagittal T2-weighted MR image shows the large intracavitary component of the fibroid (arrowhead), which is hypointense.
|
|
View larger version (128K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5c. Hyperechoic line related to an underlying submucosal fibroid. (a) Transverse endovaginal US scan shows a hyperechoic line partially surrounding a thickened central endometrial complex with a bland internal architecture (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows a submucosal fibroid with a large intracavitary component (arrow). (c) Sagittal T2-weighted MR image shows the large intracavitary component of the fibroid (arrowhead), which is hypointense.
|
|
Focal or Diffuse Process (No Hyperechoic Line).—If there is no hyperechoic line at initial endovaginal US and the endometrium is thickened or distorted, one cannot reliably distinguish between a focal and a diffuse intrauterine process (Fig 6). Seventeen patients had a thickened or distorted central endometrial complex at endovaginal US but lacked a surrounding hyperechoic line: Seven had diffuse endometrial thickening, six had polyps, four had submucosal fibroids, and two had discrete areas of endometrial thickening. In such patients, hysterosonography is necessary to differentiate focal from diffuse intracavitary disease and most appropriately direct the patient to a directed versus a blind tissue sampling technique.
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6a. Endometrial thickening related to diffuse endometrial carcinoma. (a) Longitudinal endovaginal US scan shows a thickened endometrium with no associated hyperechoic line surrounding the central endometrial complex. (b) Subsequently obtained longitudinal hysterosonogram shows diffusely thickened endometrium.
|
|
View larger version (130K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6b. Endometrial thickening related to diffuse endometrial carcinoma. (a) Longitudinal endovaginal US scan shows a thickened endometrium with no associated hyperechoic line surrounding the central endometrial complex. (b) Subsequently obtained longitudinal hysterosonogram shows diffusely thickened endometrium.
|
|
Hysterosonography
When necessary, hysterosonography can provide an acoustic window to demonstrate the intrauterine contents and surrounding myometrium. All 42 patients in our study underwent hysterosonography (Table). When hysterosonography is complementary to an endovaginal US study, certain constellations of findings make it easy to determine the underlying pathologic condition.
Focal Process.—Endometrial polyps revealed at hysterosonography were most reliably recognized by their narrow (sessile or pedunculated) attachment to the adjacent endometrium (Fig 7). This finding was appreciated on the images of all 29 patients with polyps. Although most of the polyps (23 of 29 [79%]) were hyperechoic relative to the myometrium, a few were variable in echotexture. Cystic spaces were present within the polyp in more than half of the cases (17 of 29 [59%]). The polyp was associated with a hyperechoic line at initial endovaginal US in 23 of 29 patients (79%). One patient had a focus of endometrial carcinoma within a polyp, which was otherwise indistinguishable at endovaginal US and hysterosonography from the polyps in other patients.
View larger version (123K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7a. Hysterosonographic appearance of endometrial polyps. (a) Longitudinal hysterosonogram shows an endometrial polyp with a long stalk (arrows). (b) Transverse hysterosonogram shows an endometrial polyp with central cystic changes (arrows) and a narrow attachment to the endometrium (arrowhead).
|
|
View larger version (125K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7b. Hysterosonographic appearance of endometrial polyps. (a) Longitudinal hysterosonogram shows an endometrial polyp with a long stalk (arrows). (b) Transverse hysterosonogram shows an endometrial polyp with central cystic changes (arrows) and a narrow attachment to the endometrium (arrowhead).
|
|
At hysterosonography, submucosal fibroids characteristically had an overlying rim of endometrial tissue, which helped confirm their extraendometrial location (Fig 8). We saw this sign in all five cases of fibroids. In contrast to polyps, all five fibroids had a wide attachment to the myometrium. They were variable in echotexture.
View larger version (119K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8a. Hysterosonographic appearance of submucosal fibroids. (a) Transverse hysterosonogram shows a submucosal fibroid with an overlying rim of endometrium (arrow). (b) Transverse hysterosonogram shows a submucosal fibroid with a similar overlying rim of endometrium (arrow).
|
|
View larger version (141K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8b. Hysterosonographic appearance of submucosal fibroids. (a) Transverse hysterosonogram shows a submucosal fibroid with an overlying rim of endometrium (arrow). (b) Transverse hysterosonogram shows a submucosal fibroid with a similar overlying rim of endometrium (arrow).
|
|
Focal endometrial thickening can be easily confused with polyps or fibroids at hysterosonography. Such thickening is most easily identified and distinguished by noting that it is broadly attached to the myometrium but lacks a rim of overlying endometrium. Three patients had an asymmetric area of thickened endometrium: In two patients, the thickening was related to focal endometrial hyperplasia; in the third, a localized endometrial carcinoma manifested as focal endometrial thickening, which was otherwise indistinguishable from the other cases of focally thickened endometrium (Fig 9). All foci of thickening had a broad base, were hyperechoic relative to the myometrium, and lacked an endometrial rim. One patient had the hyperechoic line sign at initial endovaginal US.
Diffuse Process.—Hysterosonography revealed diffuse endometrial thickening in seven patients. This condition was characterized by global thickening of the endometrial lining without focal asymmetry in all cases (Fig 10). The echotexture relative to the myometrium was variable. Of these seven patients, four had proliferative endometrium, two had endometrial hyperplasia, and one had diffuse endometrial carcinoma.
View larger version (143K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9a. Hysterosonographic appearance of asymmetric endometrial thickening. (a) Longitudinal hysterosonogram shows a focus of endometrial thickening along the anterior aspect of the endometrium (arrow). (b) Longitudinal hysterosonogram shows a focus of endometrial thickening near the fundal and posterior aspect of the endometrial cavity (arrow).
|
|
View larger version (117K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9b. Hysterosonographic appearance of asymmetric endometrial thickening. (a) Longitudinal hysterosonogram shows a focus of endometrial thickening along the anterior aspect of the endometrium (arrow). (b) Longitudinal hysterosonogram shows a focus of endometrial thickening near the fundal and posterior aspect of the endometrial cavity (arrow).
|
|
|
CONCLUSIONS
|
|---|
A hyperechoic line surrounding the endometrium at endovaginal US may approach 100% specificity as a predictor of an underlying focal intracavitary process. In our series, no false-positive cases of a hyperechoic line were seen in association with a diffuse process. Such a line likely reflects the interface between the surrounding endometrium and an intraluminal mass or the endometrium itself. When a hyperechoic line is observed together with cystic spaces in the central endometrial complex, it is possible to distinguish polyps from other focal masses at initial endovaginal US. In general, a hyperechoic line is valuable as a predictor of focal intracavitary disease and can be used according to the algorithm to avoid blind endometrial biopsy. When identified at initial endovaginal US, a hyperechoic line can prompt hysteroscopic management and may help avoid unnecessary additional imaging or procedures with false-negative results.
According to the algorithm, when a hyperechoic line is not present, focal and diffuse intracavitary processes can be best distinguished with hysterosonography. Among the focal abnormalities identified at hysterosonography, polyps and fibroids can be differentiated by evaluating the attachment to the endometrium or myometrium and by observing an endometrial rim in fibroids. MR imaging may be a useful adjunct in the algorithm for confirming the presence of a submucosal fibroid and distinguishing it from focal processes that need histopathologic confirmation. Internal characteristics of focal masses such as cystic spaces, which are commonly seen in polyps, may provide additional discriminating information when recognized at endovaginal US.
|
References
|
|---|
-
Nasri MN, Shepard JH, Setchell ME, Lowe DG, Chard T. Sonographic depiction of postmenopausal endometrium with transabdominal and transvaginal scanning. Ultrasound Obstet Gynecol 1991; 1:279-283.[Medline]
-
Varner RE, Sparks JM, Cameron DC, Roberts LL, Seng-Jaw S. Transvaginal sonography of the endometrium in postmenopausal women. Obstet Gynecol 1991; 78:195-199.[Free Full Text]
-
Dubinsky TJ, Parvey HR, Maklad N. The role of transvaginal sonography and endometrial biopsy in the evaluation of peri- and postmenopausal bleeding. AJR 1997; 169:145-149.[Abstract]
-
Dubinsky TJ, Parvey HR, Gormaz G, Curtis N, Maklad N. Transvaginal hysterosonography: comparison with biopsy in the evaluation of postmenopausal bleeding. J Ultrasound Med 1995; 14:887-893.[Abstract]
-
Gimes PA. Diagnostic dilation and curettage: a reappraisal. Am J Obstet Gynecol 1982; 142:1-6.[Medline]
-
Cicinelli E, Romano F, Anastasio PS, Blasi N, Parisi C. Sonohysterography versus hysteroscopy in the diagnosis of endouterine polyps. Gynecol Obstet Invest 1994; 38:266-271.[Medline]
-
Loffer FD. Hysteroscopy with selective endometrial sampling compared with D+C for abnormal uterine bleeding: the value of a negative hysteroscopic view. Obstet Gynecol 1989; 73:16-20.[Abstract/Free Full Text]
-
Cohen MR, Dmowski WP. Modern hysteroscopy: diagnostic and therapeutic potential. Fertil Steril 1973; 24:905-911.[Medline]
-
Dubinsky TJ, Parvey HR, Gormaz G, Maklad N. Transvaginal hysterosonography in the evaluation of small endoluminal masses. J Ultrasound Med 1995; 14:1-6.[Abstract]
-
Gaucherand P, Piacenza JM, Salle B, Rudigoz RC. Sonohysterography of the uterine cavity: preliminary investigations. JCU 1995; 23:339-348.
-
Weinreb JC, Barkoff ND, Megibow A, Demopoulos R. The value of MR imaging in distinguishing leiomyomas from other solid pelvic masses when sonography is indeterminant. AJR 1990; 154:295-299.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
G Michail, A Karahaliou, S Skiadopoulos, C Kalogeropoulou, G Terzis, I Boniatis, L Costaridou, G Kourounis, and G Panayiotakis
Texture analysis of perimenopausal and post-menopausal endometrial tissue in grayscale transvaginal ultrasonography
Br. J. Radiol.,
August 1, 2007;
80(956):
609 - 616.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. M. Breitkopf, R. A. Frederickson, and R. R. Snyder
Detection of Benign Endometrial Masses by Endometrial Stripe Measurement in Premenopausal Women
Obstet. Gynecol.,
July 1, 2004;
104(1):
120 - 125.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Fong, P. Causer, M. Atri, A. Lytwyn, and R. Kung
Transvaginal US and Hysterosonography in Postmenopausal Women with Breast Cancer Receiving Tamoxifen: Correlation with Hysteroscopy and Pathologic Study
RadioGraphics,
January 1, 2003;
23(1):
137 - 150.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. M. Dudiak
Invited Commentary
RadioGraphics,
January 1, 2003;
23(1):
151 - 155.
[Full Text]
[PDF]
|
|
|
Top
Abstract
INTRODUCTION
