AIUM Practice Parameter for the Performance of Ultrasound of the Female Pelvis, 2024 Revision

AIUM Practice Parameter for the Performance of Ultrasound of the Female Pelvis, 2024 Revision The American Institute of Ultrasound in Medicine (AIUM) is a multidisciplinary association dedicated to advancing the safe and effective use of ultrasound in medicine through professional and public education, research, development of clinical practice parameters, and accreditation of practices performing ultrasound examinations. The AIUM Practice Parameter for the Performance of Ultrasound of the Female Pelvis was developed and revised by the American Institute of Ultrasound in Medicine (AIUM) in collaboration with other organizations whose members use ultrasound for performing these examinations (see “Acknowledgments”). Recommendations for personnel requirements, the request for the examination, documentation, quality assurance, and safety may vary among the organizations and may be addressed by each separately. This Practice Parameter is intended to provide the medical ultrasound community with recommendations for the performance and recording of high-quality ultrasound examinations. The parameter reflects what the AIUM considers the appropriate criteria for this type of ultrasound examination but is not intended to establish a legal standard of care. Examinations performed in this specialty area are expected to follow the Parameter with the recognition that deviations may occur depending on the clinical situation. Indications - Evaluation of pelvic pain - Evaluation of pelvic masses - Evaluation of dyspareunia - Evaluation of pregnancy of unknown location or ectopic pregnancy - Evaluation of endocrine abnormalities, including polycystic ovaries - Evaluation of dysmenorrhea - Evaluation of amenorrhea - Evaluation of abnormal uterine bleeding (AUB) - Evaluation of postmenopausal bleeding - Evaluation of delayed menses - Follow-up of a previously detected abnormality - Evaluation, monitoring, and/or treatment of patients with infertility - Evaluation when there is limited clinical examination of the pelvis - Evaluation for signs or symptoms of pelvic infection - Further characterization of a pelvic abnormality noted on another imaging study - Evaluation of congenital uterine, gonadal, and lower genital tract anomalies - Evaluation of excessive bleeding, pain, or signs of infection after pelvic surgery, delivery, or abortion - Localization of an intrauterine device (IUD) - Surveillance for malignancy in high-risk patients - Evaluation of incontinence or pelvic organ prolapse - Guidance for interventional or surgical procedures - Preoperative and postoperative evaluation of pelvic structures Qualifications and Responsibilities of Personnel Physicians interpreting or performing this type of ultrasound examination should meet the specified AIUM Training Guidelines1 in accordance with AIUM accreditation policies.2 Sonographers performing the ultrasound examination should be appropriately credentialed3 in the specialty area in accordance with AIUM accreditation policies.2 Physicians not personally performing the examination must provide supervision, as defined by the Centers for Medicare and Medicaid Services Code of Federal Regulations 42 CFR §410.32,4 which is available from the U.S. Government Publishing Office. Request for the Examination The written or electronic request for an ultrasound examination must originate from a physician or other appropriately licensed health care provider or under the provider's direction. The clinical information provided should allow for the performance and interpretation of the appropriate ultrasound examination and should be consistent with relevant legal and local health care facility requirements. Specification of the Examination The following section details the examination to be performed for each organ and anatomic region in the female pelvis. All relevant structures should be identified by the transabdominal and/or transvaginal approach. A transrectal or transperineal approach may be useful in patients who are not candidates for introduction of a vaginal transducer and in assessing the patient with pelvic organ prolapse. More than one approach may be necessary.5, 6 General Pelvic Preparation For a transabdominal pelvic sonogram, a full bladder is typically needed to displace the bowel from the field of view and to provide an optimal acoustic window to better visualize the pelvic structures, particularly if a transvaginal examination cannot be performed. Occasionally, overdistention of the bladder may compromise the evaluation. When this occurs, imaging may be repeated after partial bladder emptying. If any abnormalities of the urinary bladder are detected, these findings should be documented in accordance with the AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Abdomen and/or Retroperitoneum.7 For a transvaginal sonogram, the urinary bladder is preferably empty. The patient, the sonographer, or the clinician may introduce the vaginal transducer, preferably under real-time monitoring. Consideration of having a chaperone present should be in accordance with local policy.8, 9 Two-handed technique (one hand on probe and one hand on external lower abdomen) is helpful to assess mobility of structures and may help move bowel away from the adnexa or to stabilize adnexal structures to aid in their visualization. It is recommended that the examiner inform the patient before a dynamic maneuver such as direct manual pressure on the lower abdomen or sliding of the probe is performed. Uterus The vagina and uterus provide anatomic landmarks that can be used as reference points for the other pelvic structures, whether normal or abnormal. When examining the uterus, the following should be evaluated: 1) the uterine size, shape, and orientation; 2) the endometrium; 3) the myometrium; and 4) the cervix. In children and adolescents, note should be made whether the uterine configuration is prepubertal or postpubertal. The vagina may be imaged while introducing the transducer and can be a landmark for the cervix.10, 11 Although not part of the standard examination, if evaluation of the vaginal mucosa and rectovaginal septum is desired, instillation of 20 mL of gel into the vagina with distension of the vaginal fornices may be helpful.12 Overall uterine length is evaluated in sagittal view from the fundus to the cervix (to the external os, if it can be identified). The length can be measured as a straight line from the fundus to the external os using outer-to-outer technique or by measuring from the fundal region along the endometrial lining and endocervical canal (trace method) using outer-to-outer technique.13 The depth of the uterus (anteroposterior dimension) is measured in the same sagittal view from its anterior to posterior walls, perpendicular to the longitudinal axis of the endometrium. The maximum width is measured in the transverse or coronal view. If volume measurements of the uterine corpus are performed, the cervical component should be excluded from the uterine length measurement. Note is to be made that a volume measurement of the corpus in the nongravid state is an estimate because there is no sonographic anatomic landmark for where the cervix ends and the uterine corpus begins. Abnormalities of the uterus should be documented.14-16 The myometrium and cervix should be evaluated for contour changes, echogenicity, masses, and cysts as well as symmetry between anterior and posterior myometrium. The myometrial echogenicity is reported as either homogenous or heterogeneous. If the myometrium is heterogenous due to shadowing or hyperechogenic islands, that should be specified. Myometrial lesions need to be assessed and described. When an abnormality of the myometrium is noted, the objective finding leading to this conclusion must be documented. For example, simply documenting adenomyosis as a subjective finding is insufficient and has poor reproducibility and reliability.17, 18 Note should be made when the uterus is not mobile or tenderness is elicited during the examination. Fixed retroflexion of the uterus, particularly in the presence of posterior adenomyosis, or absence of sliding between the uterus and adjacent rectum or adnexa, should be recognized as a possible indicator of pelvic adhesion seen in deep endometriosis (DE) in the posterior cul-de-sac.19 Size and location of clinically relevant lesions should be documented. Masses that may require follow-up or intervention should be measured in at least two dimensions, acknowledging that it is not usually necessary to measure all uterine fibroids. The endometrium should be evaluated for thickness, focal abnormality, echogenicity, and echotexture (homogeneous vs heterogeneous), and the presence and characteristics of fluid or masses in the uterine cavity. The thickest part of the endometrium should be measured perpendicular to its longitudinal plane in the anteroposterior diameter from echogenic to echogenic border, using outer-to-outer technique13 (see Figure 1). When fluid is present in the cavity, the endometrial thickness should be measured on either side of the fluid in the same plane and the measurements added together to report the total thickness; the fluid should be excluded in this measurement (see Figure 2). In reproductive-aged postmenarchal patients, assessment of the endometrium should allow for variations expected with phases of the menstrual cycle and with hormonal supplementation.16, 20, 21 It must be reported if the endometrium is not adequately seen in its entirety or is ill defined; in this circumstance, measurement may not be included in the report. The endometrium should be evaluated using power Doppler to assess the vascular pattern. The location of any areas of focal hypervascularity or feeding vessels should be documented. Sonohysterography may be useful to further evaluate the patient with AUB, an abnormal appearing endometrium, and to further evaluate or evaluate an incompletely visualized endometrium (see the AIUM Practice Parameter for the Performance of Sonohysterography and Hysterosalpingo-Contrast Sonography22). If the patient has an IUD, its location should be documented. The addition of 3D ultrasound (transabdominal, transvaginal, transperineal, and/or transrectal) can be helpful in many circumstances, including, but not limited to, evaluating the relationship of masses to the endometrial cavity, identifying uterine congenital anomalies and thickened and/or heterogenous endometrium, identifying uterine synechia, and evaluating the location and orientation of an IUD and the integrity of the pelvic floor.19, 23-30 Performing 3D ultrasound of the uterus may be enhanced if done in the luteal phase because the endometrium is hyperechoic and enables visualization of uterine cavity abnormalities. Adnexae Including Ovaries and Fallopian Tubes When evaluating the adnexa, an attempt should be made to identify the ovaries first because they can serve as a major point of reference for assessing the presence of adnexal pathology. Ovarian size may be determined by measuring the ovary in three dimensions (longitudinal, transverse, and anteroposterior diameters) on views obtained in two orthogonal planes31, 32 with the calculation of ovarian volume as necessary. Any ovarian abnormalities should be documented.33-38 The ovaries may not be identifiable in some individuals. This issue occurs most frequently before puberty and after menopause when the ovaries are smaller and/or follicles are not consistently present to serve as a landmark.5 The adnexal region should be surveyed for abnormalities, particularly masses and dilated tubular structures. If an adnexal abnormality is noted, its relationship to the ovaries and uterus should be assessed. The size and sonographic characteristics of adnexal masses should be documented. Any ovarian lesion should be fully documented with both gray scale and color; gray scale alone cannot determine solid versus debris-containing cystic mass. The addition of 3D to 2D ultrasound can be helpful to differentiate multilocular ovarian cysts from hydrosalpinges. The use of the sliding organ sign technique can demonstrate the presence or absence of mobility of the adnexal structures.39, 40 Abnormal ovarian location, such as in the posterior cul-de-sac with adhesion, particularly to the uterus, pelvic side wall, or contralateral ovary, should be documented because this may indicate endometriosis, other sources of adhesions, or displacement of the ovary in the setting of adnexal torsion (ovarian torsion, isolated tubal torsion, or both ovarian and tubal torsion). Asymmetrical enlargement of the ovary and peripheral location of the follicles are suggestive of ovarian torsion. Identifying the twisted vessel (“whirlpool” sign) is also helpful in making this diagnosis.41 The presence of Doppler signal does not exclude ovarian torsion. All ovarian lesions should be documented according to a validated standardized risk stratification system. A lesion is defined as a finding judged to be inconsistent with normal physiologic function. The size of the ovary and the lesion are measured in mm as the largest three diameters in two perpendicular planes. If using the Oviarian-Adnexal Imaging Reporting Data System (O-RADS), lesions are described as unilocular, unilocular-solid, multilocular, multilocular-solid, or solid. Internal contents of cysts should be described as anechoic, low-level internal echoes, ground glass internal echoes, or mixed internal echoes. Papillary projections are solid projections at least 3 mm in height when measured from the cyst wall. Papillary projections and/or the largest solid portion should be measured in three planes. Color score is measured subjectively: 1 is no vascular flow, 2 is minimal, 3 is moderate, 4 is highly vascular. If the mass has typical features that suggest a specific diagnosis, such as an endometrioma or teratoma, this information should be provided.38, 42, 43 If sonographic characteristics are suggestive of a specific diagnosis, such as hemorrhagic cyst, endometrioma, mature teratoma, hydrosalpinx, peritoneal inclusion cyst, or pedunculated fibroid, this information should also be provided.42-48 Spectral, color, and/or power Doppler ultrasound may be useful to evaluate the vascular characteristics of pelvic lesions.49-52 Cul-de-Sac The cul-de-sac and bowel posterior to the uterus should be evaluated for the presence of free or loculated fluid, or mass. If a mass is detected, its size, position, shape, sonographic characteristics, and relationship to the ovaries and uterus should be documented. Differentiation of normal loops of bowel from a mass may be difficult if only a transabdominal examination is performed. The rectosigmoid colon wall may be imaged from the posterior vaginal fornix.53 Special attention to the posterior cul-de-sac should be made in women with pelvic pain, with fixed retroflexion of the uterus, with sonographic evidence of posterior adenomyosis, and with known or clinically suspected endometriosis.19, 53 Hypoechoic masses with tapering ends in the rectosigmoid wall may be seen in DE.53, 54 The presence of adhesions in the cul-de-sac may be inferred in the absence of a normal uterine sliding sign53, 55 during dynamic imaging. Any tenderness during the ultrasound is helpful to be documented. Documentation Accurate and complete documentation is essential for high-quality patient care. Written reports and ultrasound images/video clips that contain diagnostic information should be obtained and archived, with recommendations for follow-up studies if clinically applicable, in accordance with the AIUM Practice Parameter for Documentation of an Ultrasound Examination.56 Adequate documentation is essential for high-quality patient care. There should be a permanent record of the ultrasound examination and its interpretation. Cine clips may be useful. Comparison with prior relevant imaging studies should be made and is helpful when available. Images of all appropriate areas, both normal and abnormal, should be recorded. Variations from normal size should generally be accompanied by measurements. Images should be labeled with the patient identification, facility identification, examination date, anatomic landmarks, and image orientation. An official interpretation (final report) of the ultrasound examination should be included in the patient's medical record. Retention of the ultrasound examination images should be consistent both with clinical need and with relevant legal and local healthcare facility requirements. Equipment Specifications Equipment performance monitoring should be in accordance with AIUM Routine Quality Assurance of Clinical Ultrasound Equipment.57 The sonographic examination of the female pelvis should be conducted with a real-time scanner, preferably using sector, curved linear, and/or endocavitary transducers. The transducer should be adjusted to operate at the highest frequency appropriate for clinical circumstances, realizing that there is a trade-off between resolution and beam penetration. Quality and Safety Policies and procedures related to quality assurance and improvement, safety, infection control, and equipment-performance monitoring should be developed and implemented in accordance with the AIUM Standards and Guidelines for the Accreditation of Ultrasound Practices.2 ALARA Principle The potential benefits and risks of each examination should be considered. The ALARA (As Low As Reasonably Achievable) principle58 should be observed for factors that affect the acoustical output and by considering transducer dwell time and total scanning time. Further details on ALARA may be found in the current version of the AIUM publication Medical Ultrasound Safety.59 Infection Control Transducer preparation, cleaning, and disinfection should follow manufacturer recommendations and be consistent with the AIUM's Guidelines for Cleaning and Preparing External- and Internal-Use Ultrasound Transducers Between Patients, Safe Handling, and Use of Ultrasound Coupling Gel.60 Equipment Performance Monitoring Monitoring protocols for equipment performance should be developed and implemented in accordance with the AIUM Standards and Guidelines for the Accreditation of Ultrasound Practice.2 Acknowledgments This parameter was developed by the AIUM in collaboration with the American College of Obstetricians and Gynecologists (ACOG), the American College of Radiology (ACR), the Society for Pediatric Radiology (SPR), and the Society of Radiologists in Ultrasound (SRU). We are indebted to the many volunteers who contributed their time, knowledge, and energy to developing this document. Collaborative Subcommittees AIUM Laura Detti, MD Yvette Groszmann, MD, MPH Lauri Silver Hochberg, MD Elizabeth E. Puscheck, MBA, MD, MS ACOG Wendy Brewster, MD, PhD Bethany Skinner, MD ACR Marcela Bohm-Velez, MD, Chair Harris L. Cohen, MD Malak Itani, MD Arleen Li, MD Michelle Melany, MD Roya Sohaey, MD SPR Judy Estroff, MD Jeffrey Tutman, MD SRU Rochelle E. Andreotti, MD Nadia J. Khati, MD AIUM Clinical Standards Committee Rachel Bo-ming Liu, MD, FACEP, FAIUM, Chair Margarita V. Revzin, MD, MS, FSRU, FAIUM, Vice Chair Tracy Anton, BS, RDMS, RDCS, FAIUM Creagh T. Boulger, MD, FAIUM John R. Eisenbrey, PhD, FAIUM Rob Goodman, MB, BChir, FAIUM Ethan J. Halpern, MD, FAIUM Oliver Daniel Kripfgans, PhD, FAIUM Juliana Gevaerd Martins, MD John Stephen Pellerito, MD, FACR, FAIUM, FSRU James M. Shwayder, MD, JD, FAIUM Jean Lea Spitz, MPH, CAE, RDMS, FAIUM, FSDMS Original copyright 1995; revised 1999, 2004, 2006, 2009, 2014, 2019, 2024; renamed 2015