<scp>ISUOG Consensus Statement</scp> on sonographic assessment of the endometrium: how to perform a gynecological ultrasound scan and report the findings

The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) is a scientific organization that encourages sound clinical practice and high-quality teaching and research related to diagnostic imaging in women's healthcare. The ISUOG Clinical Standards Committee (CSC) has the remit to develop Practice Guidelines and Consensus Statements as educational recommendations that provide healthcare practitioners with a consensus-based approach, from experts, for diagnostic imaging. They are intended to reflect what is considered by ISUOG to be the best practice at the time at which they are issued. Although ISUOG has made every effort to ensure that Guidelines and Consensus Statements are accurate when issued, neither the Society nor any of its employees or members accepts any liability for the consequences of any inaccurate or misleading data, opinions or statements issued by the CSC. The ISUOG CSC documents are not intended to establish a legal standard of care because interpretation of the evidence that underpins them may be influenced by individual circumstances, local protocol and available resources. Approved Guidelines and Consensus Statements can be distributed freely with the permission of ISUOG ([email protected]). The aim of ultrasonography of the endometrial cavity is to evaluate the physiological and pathological changes of the endometrium and detect intracavitary lesions. In 2010, the International Endometrial Tumor Analysis (IETA) consortium1 proposed a structured lexicon to standardize the description of the sonographic features of the endometrium and intrauterine lesions. In recent years, several IETA studies2-5 have applied this lexicon to report the typical sonographic features of normal and abnormal endometrial changes and intracavitary lesions. The initiative for this Consensus Statement came from the ISUOG CSC. Applying the IETA lexicon, we explain how to perform a gynecological ultrasound scan, focusing on endometrial evaluation, and discuss the reporting of sonographic endometrial findings, focusing on clinical relevance for diagnosis and management. This Consensus Statement will be of interest not only to gynecologists with a special interest in ultrasonography, but also to general gynecologists, those performing hysteroscopy, gynecological oncologists and fertility specialists. Pregnancy-related findings, Cesarean scar defects, congenital uterine anomalies and cancer staging are beyond the scope of this Consensus Statement. The contributors to this Consensus Statement are all experts in their fields and have expressed their opinions based on the available literature and evidence. Any clinician applying this Consensus Statement is expected to use their independent medical judgment in the context of the individual clinical circumstances to determine patient care. Twenty experts in the field of gynecological ultrasonography, hysteroscopy and oncology were invited to participate based on their expertise and geographic spread. An online poll was created to assess agreement among all coauthors on the relevant statements for the topics under discussion (Table 1). Statements that were fully or partially agreed upon by ≥ 90% of the voters remained unaltered. Nine statements did not meet this threshold and were reformulated and circulated for a second poll. Both polls were completed by 19 of the 20 participants. 18/19 (94.7) For the optimal interpretation of an ultrasound examination, the referring clinician should state clearly the reason(s) for referral and share the relevant clinical information (e.g. patient's age, height, weight, body mass index, medication, comorbidity, previous sonographic findings, latex allergy) and relevant gynecological history, including last menstrual period, age at menopause, hormonal/non-hormonal contraceptive use, hormonal replacement therapy (HRT), gravidity, parity, previous Cesarean section, previous miscarriage or previous surgery. Gynecological ultrasonography should be performed in a reassuring environment. The absence of latex allergy needs to be confirmed when working with latex probe covers. It is advised to have latex-free alternatives (e.g. nitrile gloves). Fully informing the patient and obtaining their consent before proceeding with the examination are essential. The presence of a chaperone might be particularly advisable in adolescents, patients who have had previous negative experience with gynecological (sonographic) examinations, anxious patients or elderly women6. The presence of a chaperone is, whenever possible, offered in the UK and in many other countries in all cases requiring intimate examination. This is mandatory in the UK for children, adolescents and women who are unable to give informed consent6, 7. Prior to vaginal ultrasonography, it is advised to exclude any vulvar or perineal lesions by external examination. Scanning may cause discomfort, thus it is important to communicate with the patient, to reassure them and ask them to tell the examiner whether they experience any anxiety, pain or discomfort8, 9. Before menopause, an ultrasound examination to detect endometrial lesions should preferably be performed in the early proliferative phase of the menstrual cycle (i.e. after cessation of menstrual bleeding) or after withdrawal bleeding in women taking combined hormonal contraception; in postmenopausal women on cyclic HRT, it should be performed in the estrogen-only phase of the cycle, after the end of withdrawal bleeding, or 5–10 days after the last progestin tablet, depending on the HRT scheme. In the first phase of the menstrual cycle, the endometrium typically has a uniform, hypoechogenic appearance at ultrasound, with a regular, linear midline (i.e. a three-layer pattern). A focal intracavitary lesion, such as an endometrial polyp, will distort the endometrial midline and will be easily visible against the hypoechogenic background. During menstruation, the presence of intracavitary blood (clots) may obscure the view and impede proper endometrial evaluation. In the secretory phase of the cycle, the endometrium becomes more echogenic and, at the end of the cycle, may even develop a more polypoid growth pattern (Figure 1). This may mask or mimic an intracavitary lesion. If imaging is suboptimal, especially in those presenting late in their menstrual cycle, it may be advisable to ask the patient to come back for a second ultrasound evaluation after the next bleed. Ultrasonography of the endometrium may be performed using a transvaginal, transabdominal or, less commonly, transperineal or transrectal approach. According to some local protocols, it is customary to perform both transabdominal and transvaginal ultrasonography in every patient. In most adult women, the endometrium and uterine cavity may be scanned transvaginally7. Transvaginal scanning is the preferred approach, but is contraindicated in women who are unable to give informed consent, when there is vaginal stenosis (e.g. secondary to atrophy, radiotherapy), if the patient is virgo intacta or in the presence of other contraindications for introducing a vaginal probe (e.g. risk of heavy bleeding from an exophytic cervical cancer or after recent vaginal surgery). The management of adolescents should be individualized. In most cases, the patient should be asked to empty her bladder before the examination. The patient is examined in the lithotomy position. Endocavitary ultrasound transducers are considered semicritical medical devices owing to the high risk of potential contamination10. They therefore require an appropriate probe cover and should undergo high-level disinfection after use. A probe cover, filled with gel, is placed on the probe and sufficient gel is applied to the cover before the probe is introduced gently into the vagina. In some countries the use of individual gel sachets is mandatory in view of the risk of infection. In some cases (e.g. cases of postmenopausal bleeding or when there is suspicion of endometriosis), it is advised to evaluate the bladder wall to exclude a bladder lesion (e.g. polyps, primary transitional cell carcinoma or metastatic disease11) or deep endometriosis12. In these circumstances, a minimal level of bladder filling is needed. Therefore, if the bladder is empty, the ultrasound examination may be repeated after 30 min to allow some bladder filling. For optimal interobserver agreement, it is advisable to keep image orientation (cranial, caudal, left, right) consistent within the same unit/department, and to specify the orientation if deviating from the unit's protocol. Ultrasound scanning is a dynamic examination13. For example, gentle pressure on the uterus may allow differentiation between a blood clot and a sessile endometrial polyp. Selective site-specific tenderness when applying pressure on (part of) the uterus may suggest endometritis or adenomyosis12, 14. A transabdominal scan may be preferred when the uterus has an axial position (i.e. when the long axis of the endometrium is continuous with and parallel to the long axis of the endocervical canal), in the presence of large fibroids or a globally enlarged uterus (in which case, having an empty bladder may be advisable) or when a transvaginal scan is considered inappropriate8. In most cases, before carrying out a transabdominal scan, the patient should be instructed to have a full bladder15. A (partially) full bladder the which an the ultrasound an bladder patient and the focal between the ultrasound probe and the image Applying gentle pressure with the probe the focal and may (e.g. of the patient's the wall between the probe and the In patients with or transabdominal ultrasonography may in image This should be in the scan In such cases, a vaginal probe may be it into the the wall is at its In patients with the is more which may also in imaging. the transabdominal to the the may also be A transperineal can be considered to assess perineal the and the uterine In normal circumstances, of the endometrium are owing to focal and of the in the presence of or uterine the endometrium of the uterine or even can be scanning an image to that of the transvaginal for transrectal scanning are vaginal stenosis or other contraindications for introducing a vaginal A transrectal ultrasound scan may be considered to be and informed consent are The management of adolescents should be to the If an has not had previous transrectal ultrasonography may be the patient is informed and and the examination is out in a and environment. should be in women who are unable to or consent to the for women with and in the presence of (e.g. In these imaging (e.g. transabdominal ultrasound or can be A vaginal probe can be for transrectal Before the a is applied to the A examination is performed to the of the and to the The is and the probe is gently the During the patient is asked to as if to the the of the probe has the the examination is of the uterus should with of the bladder and the The position of the uterus is and The uterus is scanned in the from to and in the from the to the an of the the image is to only the uterine The should be as large as possible, focusing on the of In the endometrium is easily The probe should be to the focal for to the a is a will the of imaging may from in uterine position when or with uterine (e.g. owing to or previous may be when the cavity is by such as or Endometrial cancer may also distort the should therefore be considered as a when the endometrium is the endometrium is to it may be to it from the endocervical If possible, the of between the endometrium and the ultrasound should be to image If the endometrium be or gel information on the endometrium and the uterine For an axial a transabdominal scan may provide if the endometrium be In many or is into the ultrasound The use of or is of for the of intracavitary such as endometrial polyps, intracavitary endometrial or and reflect the of blood The in the endometrium may be using a a of is when can be a of when only minimal can be a of when is and a of when is The optimal for the of within the uterus is between and which to a between and Endometrial blood is best when the of is parallel to the ultrasound of the the of interest should the to the to allow accurate of the The pattern within the endometrium is with to the presence of a the of the presence of the of and whether blood into the endometrium have a focal or (Figure are as or more the The may within the which is as or may as a with or may have a focal at the or a within the endometrium within the endometrium but visible at the and in image such as an absence of may be by a may not be at because the are to the ultrasound pressure with the probe or from the endometrium may also the of blood the of into the uterine cavity to on The as a negative or gel may be is if the endometrium be in its or if an intracavitary lesion is and hysteroscopy have diagnostic for the of intracavitary The endometrial is as if the endometrial the uterine cavity regular, and as having endometrial or as if there are deep (Figure The endometrium is as if the the uterine cavity is or (Figure In the presence of a intracavitary lesion, the diagnosis be made between a endometrial lesion and a blood a blood clot will an endometrial lesion, a clot within the cavity when gentle pressure is applied with the ultrasound are echogenic and on image It is to the presence of within the and to all the within the and the before the into the endocervical can be (e.g. or If the cervical is it can be gently or by applying the has into the the is under ultrasound In most cases, minimal uterine cavity using of is sufficient to allow optimal evaluation of the endometrium and the uterine is and not require any pain some women may experience after This is most in women with a of or deep In these in the absence of the use of a 30 min before may be is on the use of before in not some use them in women presenting for fertility In (e.g. patients at high risk of or with a may be is contraindicated in the presence of a or or previous on suspicion of and if be In women, should not be performed in the second of the menstrual cycle, in to to normal secretory endometrial which may give a polypoid and to the of an early the is to may cause of endometrial into the Although its negative on has not some experts in cases considered for should be or, if the pressure and the of should be to a to its gel is less to the therefore the use of gel of to the risk of If there is bleeding in the early period, is preferred to gel to with blood and the and gel may cause if there are into the uterine cavity and large of gel are ultrasound imaging is not mandatory for endometrial lesions but is for the evaluation of congenital uterine and is of for the of intracavitary fibroids and (Figure the of with intrauterine contraceptive and the evaluation of Cesarean A scan may also be of if the uterus is of a within the of an appropriate In clinical evaluation of the the examination is advisable to assess the image and the for that the examiner has this may be performed more secondary If the endometrium is not clearly the may be to a of and image The patient may be asked to on the examination the and the the transvaginal gentle pressure may be applied to the uterus from the or vaginal the the examiner may some pressure on the to the uterus or the In some cases, for some bladder filling or for to in or may the of the transvaginal probe against the uterine the endometrial to against may in the endometrial midline intracavitary lesions. In of an or axial transabdominal scanning the patient's bladder partially filled or empty, to may give ultrasound A full bladder may be in some cases, as it to position the endometrium more to the ultrasound which is optimal for its evaluation. will allow imaging of the endometrium and the uterine in the secretory phase and the endometrium is to evaluate the examination in the proliferative phase of the cycle, when the endometrium is hypoechogenic or intracavitary blood or will allow proper evaluation. may be to from endometrial During may have an a lesion. 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In such a case, the probe to the of may The presence of and its cause should be in the scan If the endometrium be clearly in its it should be as and should be made to The of cases in which the endometrium be may especially in Endometrial should be at its in the and both endometrial endometrial (Figure The should be placed on the in an and the endometrium should be at the at which it to be to the endometrial The should be in to intracavitary is the of both should be and their In the presence of an intracavitary lesion (e.g. the endometrial should the of the lesion in the as as both and of the if an intracavitary is clearly the should not be in the of endometrial lesions should be in in to If an intracavitary lesion is the endometrial is less relevant the and description of the lesion The of the intracavitary should be (e.g. An evaluation of endometrial should of endometrial the endometrial midline and the The of the endometrium is as or hypoechogenic with the of the Endometrial should be as if the endometrium is with and A endometrium has a three-layer pattern in the proliferative phase of the or a pattern in the late secretory phase of the Endometrial is as if the endometrium or The endometrial midline is as if a within the endometrium is as if a is (Figure and as or as in the absence of a The is the between the endometrium and the It is as or The the endometrium is also the The aim of gynecological ultrasonography in women with abnormal bleeding is to exclude or detect intracavitary lesions such as endometrial polyps, intracavitary endometrial endometrial cancer or Although the of this Consensus Statement is on the when abnormal uterine bleeding an ultrasound examination a evaluation of including the (e.g. (e.g. cell (e.g. bladder (e.g. (e.g. endocervical polyp, cervical cervical of endometrial and (e.g. (Figure In women with abnormal uterine bleeding, endometrial is if the endometrial is considered if the endometrium has a three-layer pattern or if the endometrial midline is and In women presenting with postmenopausal bleeding, the endometrium is considered if its is but the clinician may to use a threshold (e.g. to the and negative (Table endometrial endometrial of the and are also important in from lesions. Endometrial cancer is typically with a endometrium (i.e. in postmenopausal a the presence of a endometrial an or of focal or a high of (Figure Endometrial changes in to hormonal after menopause, a for endometrial is not to menopause, and endometrial features other are more abnormal uterine bleeding, ultrasound examination is in the first of the menstrual cycle, after bleeding has In the secretory the endometrium may and more and physiological endometrial changes may be to from In such cases, a ultrasound examination after the cessation of menstrual bleeding may be In women with a menstrual cycle, information the of the cycle and the presence or absence of a or will allow interpretation of the endometrial features at or between the endometrial the of the cycle and the should be Endometrial is by the use and of hormonal (e.g. or combined The endometrium of women on continuous hormonal therapy to be and more In the presence of an owing to of the endometrium is The endometrium should be as The endometrium the is visible and relevant sonographic features may be In patients using a the endometrium the hormonal it and in women who have a HRT, endometrial is expected to be (i.e. after the The endometrial in women using HRT is by the HRT and and to the time the at which the is According to the Society the for a endometrium is as for women on continuous combined HRT and for women on HRT there is evidence that endometrial in women using from that in women using if the is after the end of the withdrawal bleed. has even less research on the of HRT on endometrial In the absence of data, should the same endometrial as that for patients (i.e. Ultrasonography should be the examination for women with abnormal uterine bleeding on therapy (e.g. are in women with of will typically be in the within the endometrium or within In the absence of abnormal uterine bleeding, there is to perform a ultrasound evaluation of the endometrium in women on (Figure Although there is for endometrial cancer in the general gynecological ultrasonography is performed in women abnormal uterine bleeding for other such as when there is suspicion of an or Although endometrial may not have the for the ultrasound scan, it a to endometrial ultrasound in the absence of abnormal uterine have on the risk of endometrial cancer in to endometrial in the postmenopausal endometrial should not be the only sonographic that is into when on endometrial In a abnormal uterine bleeding, should be considered in the presence of or more ultrasound examination for a endometrium in postmenopausal endometrium with an and with or (Figure this has to be in a In the absence of the of a endometrium in postmenopausal may a more examination the scan, first to both intrauterine and features and second to exclude the other If both these are it can be that is patients should be advised to for any postmenopausal bleeding that may evaluation. The presence of intracavitary should be and the examiner should assess whether a for the can be Although intracavitary after to endometrial is a and not may also be secondary to bleeding to intracavitary or (e.g. polyp, with a endometrium in women taking with or The of intracavitary blood has a appearance or may a Endometrial are into the uterine The presence of endometrial can be on ultrasound by the presence of a as a and echogenic that is by the between the and the (Figure Endometrial are with endometrial after menopause, but can also be in or The of can be by dynamic with blood gentle pressure from the probe against the uterine or uterine can the presence of intracavitary lesions by or (i.e. the The use of will typically the presence of a from the and into the of the endometrium (i.e. the The risk of on Endometrial cancer within a may be on if the lesion has an if there are with an pattern or if the lesion is large The presence of intracavitary or after of the (Figure In women presenting with a focal endometrial lesion and abnormal uterine bleeding, is For the more clinical of an endometrial in or postmenopausal sonographic features can to management. The presence of with or an as as the of an endometrial or of the intracavitary lesion, should discussion on the for diagnosis of the lesion and In the absence of such the management may be management with to evaluate for at a to that the lesion is and to a management clinical and sonographic and the patient's should be into when management. focal lesions are at they should be using hysteroscopy, when the endometrium is globally may be If endometrial is based on the sonographic features and endometrial is and should be with has to detect endometrial and is a first diagnostic Ultrasound should be considered to if to the uterine cavity is If the is or or only findings, hysteroscopy is During endometrial the should be and with the sonographic If there is minimal in a with a endometrium at ultrasound scan, a lesion has most and the of the will most not be In these cases, hysteroscopy with is as a diagnostic (Figure hysteroscopy is a to of Obstetrics Gynecology and of of Gynecology and of and of Obstetrics and of of Obstetrics and of and in of Obstetrics and Gynecology of of of Obstetrics and of of Gynecology and and The of and UK of Obstetrics and This Consensus Statement should be and ISUOG Consensus Statement on sonographic of the how to perform a gynecological ultrasound scan and report the Ultrasound of and of evidence in International Society of Ultrasound in Obstetrics and Gynecology Guidelines and Consensus Statements is not to this as were created or in this and and of a The is not for the or of any information by the Any should be to the for the