Power Doppler properties of endometrial polyps and submucosal fibroids: a preliminary observational study in women with known intracavitary lesions

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1 Ultrasound Obstet Gynecol 2010; 35: Published online in Wiley InterScience ( DOI: /uog.7470 Power Doppler properties of endometrial polyps and submucosal fibroids: a preliminary observational study in women with known intracavitary lesions A. P. CIL, G. TULUNAY, M. F. KOSE and A. HABERAL Etlik Zubeyde Hanim Women s Health Teaching and Research Hospital, Ankara, Turkey KEYWORDS: ultrasonography Doppler mapping; endometrial pathology; endometrial polyp; myoma; power Doppler; submucosal fibroid; ABSTRACT Objectives To compare power Doppler flow mapping characteristics of endometrial polyps and submucosal fibroids and analyze whether two different power Doppler characteristics, single-vessel pattern and rim-like vessel pattern, can help to differentiate these focal endometrial lesions. Methods Patients suspected of having endometrial polyps or submucosal fibroids on sonohysterography were examined prospectively by transvaginal B-mode and power Doppler sonography. Single-vessel pattern and rimlike vessel pattern were considered to be characteristic of endometrial polyps and submucosal fibroids, respectively. Suspected diagnoses of the lesions according to vascular Doppler characteristics were compared with the final diagnosis following histopathological examination. Results Included in the final analysis were 49 patients with histological confirmation of the type of endometrial lesion: 32 with endometrial polyps and 17 with submucosal fibroids. Power Doppler signals were observed in 47 of these; they were not observed in two patients with endometrial polyps. Of the 32 with endometrial polyps, 26 (81.3%) endometrial polyps showed a single-vessel pattern, three (9.4%) showed a multiple-vessel pattern and one (3.1%) showed a scattered-vessel pattern. Of the 17 with submucosal fibroids, 12 (70.6%) showed a rim-like vessel pattern, three (17.6%) showed a multiplevessel pattern and two (11.8%) showed a single-vessel pattern. Single-vessel pattern was associated with two false-positive cases, but there were no false-positive cases for rim-like vessel pattern. The sensitivity, specificity and positive and negative predictive values for single-vessel pattern in diagnosing endometrial polyps were 81.2%, 88.2%, 92.9% and 71.4% and for rim-like pattern in diagnosing submucosal fibroids they were 70.6%, 100%, 100% and 86.5%, respectively. Conclusions Power Doppler blood flow mapping is a valuable tool in the diagnosis of focal endometrial pathology and is useful in distinguishing submucosal fibroids and endometrial polyps. Copyright 2010 ISUOG. Published by John Wiley & Sons, Ltd. INTRODUCTION In patients with abnormal uterine bleeding, transvaginal ultrasound (TVS) is the first-line diagnostic approach to exclude endometrial pathology. If a thickened endometrium suggests endometrial pathology, sonohysterography, office hysteroscopy or dilatation and curettage are the second-line tests preferred, depending on availability and on the suspected pathology, to exclude malignancy and to aid in the decision on management of any pathology found. However, these invasive tests cause patient discomfort and increase the cost of the examination in comparison with TVS. Because color Doppler ultrasound has been shown to detect neovascularization in tumors of different organs 1,2, its use in the differentiation of malignant from benign endometrial pathology has been investigated, some finding it useful 3 and others finding it to be of limited value 4 6. Power Doppler is a new technology with various advantages over conventional color Doppler. It is based on the amplitude of the Doppler signal but not on the Doppler frequency shift. It is insonation angleindependent, with no aliasing, and is more sensitive to low-velocity blood flow. These features make power Correspondence to: Dr A. P. Cil, Department of Obstetrics and Gynecology, Kirikkale University Faculty of Medicine, Kirikkale, Turkey ( cilaylin@gmail.com) Accepted: 11 June 2009 Copyright 2010 ISUOG. Published by John Wiley & Sons, Ltd. ORIGINAL PAPER

2 234 Cil et al. Doppler advantageous for blood flow mapping by facilitating the detection of flow and depicting more clearly and reliably the vascular architecture 7,8. Alcazar et al. used power Doppler to describe three different endometrial flow mapping patterns for endometrial cancer, hyperplasia and polyp, finding two of the patterns to be useful for differentiating types of endometrial pathology 8. Around the same time, in their study evaluating 3099 pre- and postmenopausal patients, Timmerman et al. reported the positive predictive value (PPV) of transvaginal ultrasound with color Doppler to be 81.3% for endometrial polyps and 94.2% for any intracavitary pathology 9. A difference between the color Doppler vascular patterns of intracavitary endometrial polyps and submucosal fibroids has been described 10 13, although these reports included only a small number of patients with submucosal fibroids. Regarding the vascular pattern of endometrial polyps, there is a feeding vessel beginning from the base and going through the central part of the endometrium, referred to by Timmerman et al. as the pedicle artery sign and by Alcazar et al. as the single-vessel pattern. While performing TVS with power Doppler flow mapping of endometrial pathology, we have noticed that submucosal fibroids show a unique flow mapping characteristic that differs from the multiple vessels reported on a few small color Doppler studies of these lesions 10 13, and we defined this power Doppler characteristic of submucosal fibroids as a rim-like Doppler pattern. This pattern shows a circular or semicircular vessel surrounding the focal endometrial lesion, sometimes with a few small, scattered accompanying vessels. Noting that benign focal endometrial lesions such as submucosal fibroids and endometrial polyps show different power Doppler characteristics and that the recognizable characteristic rim-like Doppler pattern of submucosal fibroids has not, to our knowledge, been defined in the English literature, we aimed to compare power Doppler flow mapping characteristics of endometrial polyps and submucosal fibroids and to analyze whether two different power Doppler characteristics could help to differentiate these two focal benign endometrial lesions. who had proliferative endometrium on histological analysis, were excluded from the statistical analysis, leaving a study population of 49 (Figure 1). This study was approved by the institutional review board of Etlik Zubeyde Hanim Women s Health Teaching and Research Hospital. It was conducted according to the guidelines for clinical studies described in the Declaration of Helsinki (as revised by the World Medical Association, Sonography TVS was performed in all patients using an Aloka Prosound SSD 5500 (Aloka Co Ltd, Tokyo, Japan) machine equipped with a MHz endovaginal probe and with 3.75-MHz color, power and pulsed Doppler capabilities. First, standard B-mode TVS was performed in order to evaluate endometrial thickness and echogenicity, and endometrial blood flow distribution was then assessed in all patients. Power Doppler sonography Power Doppler ultrasonography was used to evaluate: the presence or absence of color-coded zones that represent vascularized areas; and the vascular pattern of the endometrium (blood flow mapping). Power Doppler settings were set to achieve maximum sensitivity for detecting low-velocity flow without noise (frequency, 3.75 MHz; power Doppler gain, 16 17; filter, 2). Similar preset power Doppler ultrasound settings were used for all examinations. However, to optimize flow imaging and minimize noise and aliasing, adjustments were made to the gain wall filter. We characterized the different vascular patterns of endometrial pathology according Patients with suspicion of endometrial focal lesion (n = 53) Sonohysterography (n = 53) Focal lesion (n = 52) No focal lesion: excluded (n = 1) PATIENTS AND METHODS Between January and December 2004, 53 patients suspected on sonohysterography of having an endometrial focal lesion were examined prospectively by TVS and power Doppler. The sonographer was blinded to whether the sonohysterographically suspected diagnosis was endometrial polyp or submucosal fibroid. Power Doppler characteristics of the endometrial lesions were recorded and all patients were scheduled for a diagnostic procedure. The sonographic diagnoses of the endometrial focal lesions were compared with the histopathological diagnoses. All except three of the patients had a histopathological diagnosis. These three did not undergo any diagnostic procedure and they, as well as one patient Power Doppler sonography (single-vessel pattern, rim-like-vessel pattern, other pattern or no flow) (n = 52) Diagnostic procedure (n = 49) Submucosal fibroids (n = 17) Endometrial polyps (n = 32) No diagnostic procedure: excluded (n = 3) Figure 1 Algorithm showing the selection of the study population.

3 Power Doppler characteristics of submucosal fibroids and endometrial polyps 235 Figure 2 Transvaginal ultrasound power Doppler flow mapping showing multiple-vessel pattern in a submucosal fibroid (a), single-vessel pattern (b) and scattered-vessel pattern (c) in endometrial polyps and rim-like vessel pattern with a vessel surrounding the fibroid in a semicircular fashion (d). to the three Doppler patterns described by Alcazar et al.8 (multiple-vessel pattern, single-vessel pattern and scattered-vessel pattern, Figure 2a c) and our own rimlike vessel pattern (Figure 2d). Alcazar et al. described multiple- and scattered-vessel patterns to be characteristic of endometrial cancer and hyperplasia, respectively. Single-vessel pattern, with a single vessel penetrating from the myometrium into the endometrium (Figure 2b) was considered to be characteristic of endometrial polyp. Rimlike vessel pattern, with a circular or semicircular vessel surrounding the focal endometrial lesion, sometimes with a few small scattered accompanying vessels (Figure 2d) was considered to be characteristic of submucosal fibroid. Statistical analysis The Shapiro Wilks test was used to assess the distribution of continuous data. Continuous data were compared using Student s t-test or the Mann Whitney U-test according to whether or not the distribution was normal. Categorical data were compared using the chi-square or Fisher s exact test. Sensitivity, specificity, PPV and negative predictive values (NPV) were calculated for single-vessel pattern in the prediction of endometrial polyp and rim-like vessel pattern in the prediction of submucosal fibroid. A P-value 0.05 was considered statistically significant for all tests. Statistical analysis was performed using the SPSS 11.0 statistical package (SPSS Inc., Chicago, IL, USA). Management and histopathological examination Forty-three patients underwent hysteroscopy and one had a total abdominal hysterectomy within 2 weeks after power Doppler examination. Five patients preferred to have dilatation and curettage rather than undergoing hysteroscopy with anesthesia; their histopathological analysis revealed endometrial polyps. Copyright 2010 ISUOG. Published by John Wiley & Sons, Ltd. RESULTS Of the 49 patients, 32 had endometrial polyps and 17 had submucosal fibroids on histopathology. Patients with endometrial polyps were significantly older than were patients with submucousal fibroids (48.9 ± 13.6 vs ± 8.3 years, P = 0.011). The body mass index of the Ultrasound Obstet Gynecol 2010; 35:

4 236 Cil et al. Table 1 Sonographic characteristics of patients with endometrial pathology Characteristic Endometrial polyp (n = 32) Submucosal fibroid (n = 17) P B-mode sonography ET (mm) 15.3 ± ± * Endometrial echogenicity Hyperechoic 31 (96.9) 1 (5.9) < Hypoechoic 1 (3.1) 8 (47.1) < Isoechoic 0 8 (47.1) < Pattern on Doppler imaging Single-vessel 26 (81.3) 2 (11.8) < Rim-like vessel 0 12 (70.6) < Multiple-vessel 3 (9.4) 3 (17.6) Scattered-vessel 1 (3.1) 0 No flow detected 2 (6.3) 0 Data are given as mean ± SD or n (%). *Student s t-test. Chi-square or Fisher s exact test. ET, endometrial thickness. patients in the two groups was similar (30.1 ± 8.2 vs ± 7.1, P = 0.3). There were 12 (37.5%) asymptomatic patients in the endometrial polyp group and two (11.8%) in the submucosal fibroid group (P = 0.095). In the remaining patients the major symptoms were: postmenopausal bleeding (n = 9, 28.1%), menometrorrhagia (n = 6, 18.8%) and menorrhagia (n = 5, 15.6%) in the endometrial polyp group, and menometrorrhagia (n = 13, 76.5%), menorrhagia (n = 1, 5.9%) and bloody discharge (n = 1, 5.9%) in the submucosal fibroid group. Table 1 presents the sonographic characteristics of the endometrial pathologies. The fibroids were Type 0 according to the European Society of Hysteroscopy 14, having their entire volume in the endometrial cavity and being attached to its wall with a thin pedicle. A large majority (81.3%) of the endometrial polyps showed a single-vessel pattern and a majority (70.6%) of submucosal fibroids showed a rim-like vessel pattern. The rim-like vessel pattern occurred in no patient with endometrial polyps, while the single-vessel pattern, considered characteristic of polyps, occurred in two of those with submucosal fibroids, i.e. two false-positive cases. There were no false-positive cases for the rim-like vessel pattern. The sensitivity, specificity, PPV and NPV for single-vessel pattern in diagnosing endometrial polyps were 81.3%, 88.2%, 92.9% and 71.4% and for rim-like vessel pattern in diagnosing submucosal fibroids they were 70.6%, 100%, 100%, and 86.5%, respectively. DISCUSSION Transvaginal color or power Doppler ultrasound flow mapping is reported to be of clinical value in diagnosing endometrial pathology such as endometrial cancer and endometrial polyps, but a discriminatory Doppler vessel pattern has not been attributed to submucosal fibroids 3,8,9. In this study, we described a rim-like vessel pattern characteristic of submucosal fibroids that may be helpful in their diagnosis and in distinguishing them from endometrial polyps. Although sonohysterography remains the best means with which to diagnose intrauterine endometrial lesions, it is more costly, requires additional materials and is timeconsuming compared with power Doppler. Moreover, an intracavitary pedunculated myoma on a stalk may appear as a polyp, while a broad-based polyp with a wide attachment to the endometrial surface may appear fibroid-like. In these situations and in those areas where sonohysterography is not available because of lack of catheters or expertise, power Doppler, as a non-invasive, simple and quick procedure, may be helpful in distinguishing these lesions and could improve preoperative planning. There are only a few studies comparing color Doppler imaging of endometrial polyps with that of submucosal fibroids Color Doppler studies focusing on endometrial polyps and submucosal fibroids have described a multiple-vessel pattern for submucosal fibroids 10,12. In contrast, we found that of the 17 patients with submucosal fibroids, only 17.6% showed a multiple-vessel pattern (Figure 2a), while 12% showed the single-vessel pattern that is considered to be characteristic of endometrial polyps, and 70.6% showed a typical rim-like vessel pattern, which was never seen with endometrial polyps. Of note, according to our results, if a sonographer observes a rim-like vessel pattern in an endometrial lesion, it is very unlikely that it will be anything other than a submucosal fibroid. In our experience, presence of a rim-like vessel pattern surrounding the fibroid in a circular or semicircular fashion is more useful and discriminatory for fibroids than is the multiple vessel pattern described in other studies 10,12. The sensitivity and PPV of rim-like vessel pattern on power Doppler imaging in diagnosing submucosal fibroids were 70.6% and 100%, respectively. The sensitivity and PPV of single-vessel pattern in diagnosing endometrial polyps were 81.2% and 92.9%, respectively, in agreement with published studies 9,10. Alcazar et al. 8 reported a sensitivity of 89.2% in patients with postmenopausal bleeding for single-vessel pattern, while Timmerman et al. 9 reported a sensitivity of 76% in patients evaluated irrespective of symptoms and 83.9% in patients with abnormal bleeding. We acknowledge the limitations of our study, including the small study population and our evaluation of only pathological endometrium. This was an observational study of a preselected group and is not therefore clinically relevant to the general population. This study should be carried out in a large patient population including symptomatic and asymptomatic patients with pathological and normal endometria. It should be borne in mind that submucosal fibroids tend to be more common in younger women compared with endometrial polyps, as confirmed by our study and others 9. Timmerman et al. in their study evaluating 3099 pre- and postmenopausal patients found that those presenting with endometrial polyps tended to be older 9, observing only 12 submucosal

5 Power Doppler characteristics of submucosal fibroids and endometrial polyps 237 fibroids in the population in whom the histopathological diagnosis (gold standard) was available. Therefore, the number of patients from an unselected population needed for evaluation to find numbers of fibroids and polyps comparable to those in our study would be quite high. This would explain why studies evaluating the discrimination of endometrial pathologies using Doppler imaging in patients with postmenopausal bleeding might be unable to identify submucosal fibroids. Prospective studies are required to determine the true predictive power and performance of Doppler in women with abnormal bleeding, as our study was not able to address this. In conclusion, in our experience power Doppler flow mapping is a valuable tool for diagnosing focal endometrial pathology and is useful in distinguishing between focal endometrial lesions such as submucosal fibroids and endometrial polyps. The effectiveness of single-vessel pattern or pedicle artery sign to indicate endometrial polyps is well established by others and confirmed by our study, but future research by different investigators is needed to assess reproducibility and interand intraobserver variability of rim-like vessel pattern in the identification of submucosal fibroids. REFERENCES 1. Taylor KJ, Ramos I, Carter D, Morse SS, Snower D, Fortune K. Correlation of Doppler US tumor signals with neovascular morphologic features. Radiology 1988; 166: Emoto M, Iwasaki H, Mimura K, Kawarabayashi T, Kikuchi M. Differences in the angiogenesis of benign and malignant ovarian tumors, demonstrated by analyses of color Doppler ultrasound, immunohistochemistry, and microvessel density. Cancer 1997; 80: Bourne TH, Campbell S, Steer CV, Royston P, Whitehead MI, Collins WP. Detection of endometrial cancer by transvaginal ultrasonography with color flow imaging and blood flow analysis: a preliminary report. Gynecol Oncol 1991; 40: Sladkevicius P, Valentin L, Marsal K. Endometrial thickness and Doppler velocimetry of the uterine arteries as discriminators of endometrial status in women with postmenopausal bleeding: a comparative study. Am J Obstet Gynecol 1994; 171: Sheth S, Hamper UM, McCollum ME, Caskey CI, Rosensgein NB, Kurman RJ. Endometrial blood flow analysis in postmenopausal women: can it help differentiate benign from malignant causes of endometrial thickening? Radiology 1995; 195: Chan FY, Chau MT, Pun TC, Lam C, Ngan HY, Leong L, Wong RL. Limitations of transvaginal sonography and color Doppler imaging in the differentiation of endometrial carcinoma from benign lesions. J Ultrasound Med 1994; 13: Martinoli C, Derchi LE, Rizatto G, Solbiati L. Power Doppler sonography: general principles, clinical applications, and future prospects. Eur Radiol 1998; 8: Alcázar JL, Castillo G, Mínguez JÁ, Galán MJ. Endometrial blood flow mapping using transvaginal power Doppler sonography in women with postmenopausal bleeding and thickened endometrium. Ultrasound Obstet Gynecol 2003; 21: Timmerman D, Verguts J, Konstantinovic ML, Moerman P, Van Schoubroeck D, Deprest J, van Huffel S. The pedicle artery sign based on sonography with color Doppler imaging can replace second-stage test in women with abnormal bleeding. Ultrasound Obstet Gynecol 2003; 22: Fleischer AC, Shappell HW. Color Doppler sonohysterography of endometrial polyps and submucosal fibroids. J Ultrasound Med 2003; 22: Fleischer AC, Shappell HW, Parker LP, Hanemann C. Color Doppler sonography of endometrial masses. J Ultrasound Med 2002; 21: Tamura-Sadamori R, Emoto M, Naganuma Y, Hachisuga T, Kawarabayashi T. The sonohysterographic difference in submucosal uterine fibroids and endometrial polyps treated by hysteroscopic surgery. J Ultrasound Med 2007; 26: Jakab A Jr, Ovári L, Juhász B, Birinyi L, Bacskó G, Tóth Z. Ultrasound diagnosis of focal intrauterine lesions. Orv Hetil 2002; 143: Wamsteker K, Emanuel MH, de Kruif JH. Transcervical hysteroscopic resection of submucous fibroids for abnormal uterine bleeding: results regarding the degree of intramural extension. Obstet Gynecol 1993; 82: