Society of Radiologists in Ultrasound Consensus on Routine Pelvic US for Endometriosis.

Endometriosis is a prevalent and potentially debilitating condition that mostly affects individuals of reproductive age, and often has a substantial diagnostic delay. US is usually the first-line imaging modality used when patients report chronic pelvic pain or have issues of infertility, both common symptoms of endometriosis. Other than the visualization of an endometrioma, sonologists frequently do not appreciate endometriosis on routine transvaginal US images. Given a substantial body of literature describing techniques to depict endometriosis at US, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to make recommendations aimed at improving the screening process for endometriosis. The panel was composed of experts in the imaging and management of endometriosis, including radiologists, sonographers, gynecologists, reproductive endocrinologists, and minimally invasive gynecologic surgeons. A comprehensive literature review combined with a modified Delphi technique achieved a consensus. This statement defines the targeted screening population, describes techniques for augmenting pelvic US, establishes direct and indirect observations for endometriosis at US, creates an observational grading and reporting system, and makes recommendations for additional imaging and patient management. The panel recommends transvaginal US of the posterior compartment, observation of the relative positioning of the uterus and ovaries, and the uterine sliding sign maneuver to improve the detection of endometriosis. These additional techniques can be performed in 5 minutes or less and could ultimately decrease the delay of an endometriosis diagnosis in at-risk patients.

Roadmap to safety: a single center study of evidence-informed approach to placenta accreta spectrum.

Objective: To assess the impact of an evidence-informed protocol for management of placenta accreta spectrum (PAS). Methods: This was a retrospective cohort study of patients who underwent cesarean hysterectomy (c-hyst) for suspected PAS from 2012 to 2022 at a single tertiary care center. Perioperative outcomes were compared pre- and post-implementation of a standardized Multidisciplinary Approach to the Placenta Service (MAPS) protocol, which incorporates evidence-informed perioperative interventions including preoperative imaging and group case review. Intraoperatively, the MAPS protocol includes placement of ureteral stents, possible placental mapping with ultrasound, and uterine artery embolization by interventional radiology. Patients suspected to have PAS on prenatal imaging who underwent c-hyst were included in the analysis. Primary outcomes were intraoperative complications and postoperative complications. Secondary outcomes were blood loss, need for ICU, and length of stay. Proportions were compared using Fisher's exact test, and continuous variables were compared used t-tests and Mood's Median test. Results: There were no differences in baseline demographics between the pre- (n = 38) and post-MAPS (n = 34) groups. The pre-MAPS group had more placenta previa (95% pre- vs. 74% post-MAPS, p = 0.013) and prior cesarean sections (2 prior pre- vs. 1 prior post-MAPS, p = 0.012). The post-MAPS group had more severe pathology (PAS Grade 3 8% pre- vs. 47% post-MAPS, p = 0.001). There were fewer intraoperative complications (39% pre- vs.3% post-MAPS, p < 0.001), postoperative complications (32% pre- vs.12% post-MAPS, p = 0.043), hemorrhages >1l (95% pre- vs.65% post-MAPS, p = 0.001), ICU admissions (59% pre- vs.35% post-MAPS, p = 0.04) and shorter hospital stays (10 days pre- vs.7 days post-MAPS, p = 0.02) in the post-MAPS compared to pre-MAPS patients. Neonatal length of stay was 8 days longer in the post-MAPS group (9 days pre- vs. 17 days post-MAPS, p = 0.03). Subgroup analyses demonstrated that ureteral stent placement and uterine artery embolization (UAE) may be important steps to reduce complications and ICU admissions. When comparing just those who underwent UAE, patients in the post-MAPS group experienced fewer hemorrhages greater five liters (EBL >5l 43% pre- vs.4% post-MAPS, p = 0.007). Conclusion: An evidence-informed approach to management of PAS was associated with decreased complication rate, EBL >1l, ICU admission and length of hospitalization, particularly for patients with severe pathology.

Assessment of Amniotic Fluid Volume in Pregnancy.

Amniotic fluid (AF) is an integral part of the fetal environment and is essential for fetal growth and development. Pathways of AF recirculation include the fetal lungs, swallowing, absorption through the fetal gastrointestinal tract, excretion through fetal urine production, and movement. In addition to being a marker for fetal health, adequate AF is necessary for fetal lung development, growth, and movement. The role of diagnostic imaging is to provide a detailed fetal survey, placental evaluation, and clinical correlation with maternal conditions to help identify causes of AF abnormalities and thereby enable specific therapy. Oligohydramnios prompts evaluation for fetal growth restriction as well as genitourinary issues, including renal agenesis, multicystic dysplastic kidneys, ureteropelvic junction obstruction, and bladder outlet obstruction. Premature preterm rupture of membranes should also be clinically excluded as a cause of oligohydramnios. Clinical trials evaluating amnioinfusion are underway as a potential intervention for renal causes of oligohydramnios. Most cases of polyhydramnios are idiopathic, with maternal diabetes being a common cause. Polyhydramnios prompts evaluation for fetal gastrointestinal obstruction and oropharyngeal or thoracic masses, as well as neurologic or musculoskeletal anomalies. Amnioreduction is performed only for maternal indications such as symptomatic polyhydramnios causing maternal respiratory distress. Polyhydramnios with fetal growth restriction is paradoxical and can occur with maternal diabetes and hypertension. When these maternal conditions are absent, this raises concern for aneuploidy. The authors describe the pathways of AF production and circulation, US and MRI assessment of AF, disease-specific disruption of AF pathways, and an algorithmic approach to AF abnormalities. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Noninvasive prenatal screening and maternal malignancy: role of imaging.

Noninvasive prenatal screening (NIPS) tests for fetal chromosomal anomalies through maternal blood sampling. It is becoming widely available and standard of care for pregnant women in many countries. It is performed in the first trimester of pregnancy, usually between 9 and 12 weeks. Fragments of fetal cell-free deoxyribonucleic acid (DNA) floating in maternal plasma are detected and analyzed by this test to assess for chromosomal aberrations. Similarly, maternal tumor-derived cell-free DNA (ctDNA) released from the tumor cells also circulates in the plasma. Hence, the presence of genomic anomalies originating from maternal tumor-derived DNA may be detected on the NIPS-based fetal risk assessment in pregnant patients. Presence of multiple aneuploidies or autosomal monosomies are the most commonly reported NIPS abnormalities detected with occult maternal malignancies. When such results are received, the search for an occult maternal malignancy begins, in which imaging plays a crucial role. The most commonly detected malignancies via NIPS are leukemia, lymphoma, breast and colon cancers. Ultrasound is a reasonable radiation-free modality for imaging during pregnancy, specially when there are localizing symptoms or findings, such as palpable lumps. While there are no consensus guidelines on the imaging evaluation for these patients, when there are no localizing symptoms or clinically palpable findings, whole body MRI is recommended as the radiation-free modality of choice to search for an occult malignancy. Based on clinical symptoms, practice patterns, and available resources, breast ultrasound, chest radiographs, and targeted ultrasound evaluations can also be performed initially or as a follow-up for MRI findings. CT is reserved for exceptional circumstances due to its higher radiation dose. This article intends to increase awareness of this rare but stressful clinical scenario and guide imaging evaluation for occult malignancy detected via NIPS during pregnancy.

The radiologist's role in a multidisciplinary approach to cancer in pregnancy.

Pregnancy-associated cancer (PAC) occurs in approximately 1 in 1000 pregnancies, and the incidence is expected to rise due to delayed childbearing (Silverstein et al. in JCO Oncol Pract 16:545-557, 2020; Woitek et al. in ESMO Open 1:e000017, 2016). Diagnosis and management of PACs are challenging and diagnosis is often delayed as symptoms may overlap with physiologic changes of pregnancy (Jha et al. in RadioGraphics 42:220005, 2022). These patients are best cared for by a multidisciplinary healthcare team composed of experts (Silverstein et al. in JCO Oncol Pract 16:545-557, 2020). Management of these patients must balance optimal maternal care with potentially harmful fetal effects. This involves honest, forthright, and sometimes difficult discussions between the care team and the patient throughout the entirety of care. Radiologists play a significant role in timely cancer diagnosis, staging and follow-up during and after pregnancy, accurate determination of gestational age, and in assessing fetal growth and well-being throughout pregnancy.

Imaging Cancer in Pregnancy.

Pregnancy-associated cancer (PAC) is defined as cancer that is detected during pregnancy and up to 1 year postpartum. Although rare (~1:1000 pregnancies), PAC is increasing owing to postponed childbearing and advanced maternal age at conception. Cancer-related symptoms masked by physiologic gestational changes may delay diagnosis. Imaging, clinical management, and treatment require a carefully choreographed multidisciplinary team approach. The risk-benefit of every imaging modality, the strategies to balance the safety of mother and fetus, and the support of the patient and family at every step are crucial. US and MRI are preferred imaging modalities that lack ionizing radiation. Radiation dose concerns should be addressed, noting that most imaging examinations (including mammography, radiography, CT, and technetium 99m-labeled sulfur colloid sentinel lymph node staging) are performed at radiation levels below thresholds at which deterministic side effects are seen. Dose estimates should be provided after each examination. The use of iodinated intravenous contrast material is safe during pregnancy, but gadolinium-based contrast material should be avoided. Accurate diagnosis and staging combined with gestational age affect decisions about surgery and chemotherapy. Whole-body MRI with diffusion-weighted sequences is ideal to screen for primary and metastatic sites, determine disease stage, identify biopsy targets, and guide further cancer site-specific imaging. The authors provide an update of the imaging triage, safety considerations, cancer-specific imaging, and treatment options for cancer in pregnancy. An invited commentary by Silverstein and Van Loon is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Transvaginal Ultrasound-Guided Fine-Needle Aspiration Biopsy of Pelvic Lesions.

OBJECTIVES: To assess adequacy of transvaginal ultrasound-guided fine-needle aspiration biopsy (TVUS-FNAB) for pathologic diagnosis of pelvic masses performed using onsite cytopathology consultation. METHODS: In this Institutional Review Board approved, Health Insurance Portability and Accountability Act (HIPAA) compliant study, radiology records were retrospectively queried to identify patients who underwent TVUS-FNAB of a pelvic mass over a 11-year duration. TVUS-FNAB adequacy was determined by correlating cytopathology results with transvaginal ultrasound-guided core-needle biopsy (TVUS-CNB) or surgical pathology results when available, and with clinical diagnostic confidence when additional pathology confirmation was not available. Secondary analysis included patient age, history of hysterectomy, or pelvic malignancy. Target-specific features analyzed included mass size, depth, location, and final pathologic diagnosis. RESULTS: Sixty patients underwent TVUS-FNAB of pelvic masses, 43 of which underwent FNAB only and 17 underwent both TVUS-FNAB and TVUS-CNB during the same procedure. TVUS-FNAB alone was adequate for diagnosis in 51 (85%) cases and addition of core-needle biopsy (CNB) achieved a diagnosis in additional 4 patients, increasing overall diagnostic accuracy to 92% (55/60). FNAB inadequacy had statistically significant association with increasing mass depth, occurrence of a minor intraprocedural complication, and decision to perform a CNB (P <.05). Number of FNAB passes, mass size, history of hysterectomy, and final diagnosis were not statistically significant predictors of FNAB adequacy. CONCLUSION: TVUS-FNAB has a high specimen adequacy rate when performed with an onsite cytopathologist and can be considered first-line approach for image-guided sampling of pelvic lesions with option to add CNB if preliminary cytopathologic review does not confirm sample adequacy.

Ovarian cancer reporting lexicon for computed tomography (CT) and magnetic resonance (MR) imaging developed by the SAR Uterine and Ovarian Cancer Disease-Focused Panel and the ESUR Female Pelvic Imaging Working Group.

OBJECTIVES: Imaging evaluation is an essential part of treatment planning for patients with ovarian cancer. Variation in the terminology used for describing ovarian cancer on computed tomography (CT) and magnetic resonance (MR) imaging can lead to ambiguity and inconsistency in clinical radiology reports. The aim of this collaborative project between Society of Abdominal Radiology (SAR) Uterine and Ovarian Cancer (UOC) Disease-focused Panel (DFP) and the European Society of Uroradiology (ESUR) Female Pelvic Imaging (FPI) Working Group was to develop an ovarian cancer reporting lexicon for CT and MR imaging. METHODS: Twenty-one members of the SAR UOC DFP and ESUR FPI working group, one radiology clinical fellow, and two gynecologic oncology surgeons formed the Ovarian Cancer Reporting Lexicon Committee. Two attending radiologist members of the committee prepared a preliminary list of imaging terms that was sent as an online survey to 173 radiologists and gynecologic oncologic physicians, of whom 67 responded to the survey. The committee reviewed these responses to create a final consensus list of lexicon terms. RESULTS: An ovarian cancer reporting lexicon was created for CT and MR Imaging. This consensus-based lexicon has 6 major categories of terms: general, adnexal lesion-specific, peritoneal carcinomatosis-specific, lymph node-specific, metastatic disease -specific, and fluid-specific. CONCLUSIONS: This lexicon for CT and MR imaging evaluation of ovarian cancer patients has the capacity to improve the clarity and consistency of reporting disease sites seen on imaging. KEY POINTS: • This reporting lexicon for CT and MR imaging provides a list of consensus-based, standardized terms and definitions for reporting sites of ovarian cancer on imaging at initial diagnosis or follow-up. • Use of standardized terms and morphologic imaging descriptors can help improve interdisciplinary communication of disease extent and facilitate optimal patient management. • The radiologists should identify and communicate areas of disease, including difficult to resect or potentially unresectable disease that may limit the ability to achieve optimal resection.

Boba sign with a twist - A variant presentation of a mature cystic teratoma complicated by torsion and rupture.

While mature cystic teratomas are relatively common ovarian neoplasms typically comprising of multiple embryologic cell types, a specific monodermal subtype involving thyroid tissue, struma ovarii, can rarely be seen. This case reviews typical imaging characteristics with MRI and ultrasound of struma ovarii and details possible complications from these masses with intraoperative and histologic correlation.

Müllerian Duct Anomalies: Role in Fertility and Pregnancy.

Müllerian duct anomalies (MDAs) have important implications for the reproductive health of female patients. In patients with both infertility and recurrent pregnancy loss, the incidence of MDAs is as high as 25%. Congenital uterine anomalies are often only part of a complex set of congenital anomalies involving the cervix, vagina, and urinary tract. Multiple classification systems for MDAs exist, each with different criteria that vary most for the diagnosis of septate uterus. Recognizing the features that guide clinical management is essential for interpretation. Identification of an MDA should prompt evaluation for associated urinary tract anomalies. In patients with infertility who seek to use assisted reproductive technologies such as intrauterine insemination, recognition of MDAs may have an affect on reproductive success, particularly in patients who have an incomplete and clinically occult septum that divides the cervix. Two-dimensional US is the first-line modality for evaluating the uterus and adnexa. Three-dimensional (3D) US or MRI may help to visualize the external uterine fundal contour and internal indentation of the endometrial cavity, which are two morphologic characteristics that are keys to the diagnosis of congenital uterine anomalies. Hysterosalpingo contrast-enhanced US may be performed in conjunction with 3D US to evaluate uterine morphologic characteristics, the endometrial cavity, and tubal patency in a single examination. MRI helps to characterize rudimentary uteri in patients with müllerian hypoplasia and allows assessment for ectopic ureters, abnormally positioned ovaries, or associated deep infiltrative endometriosis. Online supplemental material is available for this article. ©RSNA, 2021.

US-guided Interventions to Diagnose and Treat Gynecologic and First-Trimester Disease.

US-guided procedures have an essential role in the diagnosis and treatment of multiple obstetric and gynecologic conditions, can be performed with either transvaginal or transabdominal approaches, and include biopsy of masses, aspiration of fluid collections, injection of therapeutic materials, and saline-infused sonohysterography and hysterosalpingo contrast-enhanced sonography. The full digital presentation is available online. ©RSNA, 2021.

Differentiating complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia: A series of 9 cases and review of the literature.

To identify the differentiating features in clinical presentation, management, and maternal/fetal outcome in complete hydatidiform mole and coexistent fetus compared with placental mesenchymal dysplasia. Between 1997 and 2015, five women with complete hydatidiform mole and coexistent fetus and four women with placental mesenchymal dysplasia were managed at the University of California San Francisco. Clinical features were analyzed and compared with previously published data. Of the five cases of complete hydatidiform mole and coexistent fetus, two had live births. ß-hCG levels were > 200,000 IU/L in all cases. On imaging, a clear plane between the cystic component and the placenta favored a diagnosis of complete hydatidiform mole and coexistent fetus. None of the patients went on to develop gestational trophoblastic neoplasia (GTN), with a range of follow-up from 2 to 38 months. Combining this data with previously published work, the live birth rate in these cases was 38.8%, the rate of persistent GTN was 36.2%, and the rate of persistent GTN in patients with reported live births was 27%. Of the four cases of placental mesenchymal dysplasia, all four had live births. One patient developed HELLP syndrome and intrauterine growth restriction; the remaining three were asymptomatic. Maternal symptoms, fetal anomalies, ß-hCG level, and placental growth pattern on imaging may help differentiate between complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia. There was not an increased risk of gestational trophoblastic neoplasia in patients with complete hydatidiform mole and coexistent fetus who opted to continue with pregnancy.

ACR Appropriateness Criteria® Second and Third Trimester Screening for Fetal Anomaly.

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR appropriateness criteria second and third trimester screening for fetal anomaly

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ultrasound features help identify patients who can undergo noninvasive management for suspected retained products of conception: a single institutional experience.

OBJECTIVES: To evaluate ultrasound (US) features associated with successful noninvasive management for suspected retained products of conception (RPOC). METHODS: In this IRB-approved retrospective study, the radiology report database was queried for pelvic US with keywords of postpartum hemorrhage (PPH) and/or RPOC over a 2-year period. Follow-up exams, US exams without clinical follow-up, suboptimal image quality, and > 1 year from delivery or pregnancy termination were excluded. Charts were reviewed for clinical presentation and management. Two radiologists reviewed images for endometrial thickness, endometrial echogenicity, endometrial vascularity, and enhanced myometrial vascularity (EMV), as well as inner myometrial peak systolic velocity (PSV) and resistive index (RI) where available. Features were assessed for associations with management approach, and test characteristics were calculated. RESULTS: Initial query yielded 196 exams, and 48 were excluded. A total of 148 patients were included. Mean age was 34.2 years (21-47), and mean time from delivery or pregnancy termination was 40.4 days (0-223). 81 (55%) underwent noninvasive management: 72 (48%) expectant and 9 (6%) medical. 67 (45%) underwent invasive management: 60 (41%) surgical and 7 (5%) uterine artery embolization. There was substantial inter-reader agreement for assessment of EMV (K = 0.78) and endometrial vascularity (K = 0.72). Thin endometrial stripe, avascular endometrium, and absence of EMV were associated with successful noninvasive management (p < 0.05). Thin endometrium (< 10 mm) had specificity (90%), PPV (88%), and likelihood ratio (5.91) in predicting successful noninvasive management. CONCLUSION: Endometrial thickness < 10 mm, avascular endometrium, and absence of EMV are the sonographic features associated with successful noninvasive management for PPH or suspected RPOC.

Placental thickness correlates with placenta accreta spectrum (PAS) disorder in women with placenta previa.

OBJECTIVE: To evaluate the association of placental thickness with placenta accreta spectrum disorder in placenta previa. METHODS: In this IRB-approved, retrospective study, ultrasound (US) reports were retrospectively queried for keyword previa. US performed closest to mid-gestation were included. Three measurements were performed at the thickest portion of the placenta on longitudinal transabdominal images. Operative reports and surgical pathology were used as the reference standard. Statistical analysis was performed using unpaired T-tests and receiver operating curve (ROC) analysis. RESULTS: Sixty-five patients with placenta previa were included: 38 with PAS disorder and 27 without PAS disorder, clinically or pathologically. 38/38 (100%) patients of PAS group and 16/27 (59.3%) patients of non-PAS group had history of prior cesarean section. The average placental thickness was 4.3 cm (range 1.8 cm to 7.8 cm) for PAS group and 3.0 cm (range 0.6 cm to 5.3 cm) for non-PAS group (p < 0.001). Placental thickness in patients without PAS disorder and history of prior cesarean section was 3.1 (± 1.1) cm. This was statistically different from patients who had history of prior cesarean section with PAS diagnosis (4.3 cm, P<0.01). Using ROC analysis, a threshold measurement of 4.5 cm leads to sensitivity of 50% and specificity of 96%. CONCLUSION: Our results demonstrate that among women with placenta previa, increased placental thickness at lower uterine segment correlates with placenta accreta spectrum disorder. A threshold of 4.5 cm can be useful for screening patients with placenta previa and risks factors for PAS.

ACR Appropriateness Criteria® Nuchal Translucency Evaluation at 11 to 14 Weeks of Gestation.

A fetus with an increased nuchal translucency at 11 to 14 weeks gestation is at risk for aneuploidy, genetic syndromes, structural anomalies, and intrauterine fetal demise in both single and twin gestations. In addition to referral to genetics for counseling and consideration of diagnostic genetic testing, a detailed anatomic survey and fetal echocardiogram are indicated in the second trimester to screen for congenital malformations and major heart defects. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Second and Third Trimester Vaginal Bleeding.

Vaginal bleeding can occur throughout pregnancy with varied etiologies. Although history and physical examination can identify many etiologies, imaging, in particular ultrasound (US), is the backbone of current medical practice. US pregnant uterus transabdominal, US pregnant uterus transvaginal, and US duplex Doppler velocimetry are usually appropriate for the evaluation of women with painless vaginal bleeding, those with painful vaginal bleeding, and also for those with second or third trimester vaginal bleeding with suspicion of or known placenta previa, low-lying placenta, or vasa previa. US cervix transperineal may be appropriate for those with painless or painful vaginal bleeding but is usually not appropriate for second or third trimester vaginal bleeding with suspicion of or known placenta previa, low-lying placenta, or vasa previa. Because the outcome of pregnancies is unequivocally related to the specific etiology of the vaginal bleeding, knowledge of imaging results directly informs patient management to optimize the outcome for mother and fetus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Classification and reporting guidelines for the pathology diagnosis of placenta accreta spectrum (PAS) disorders: recommendations from an expert panel.

The terminology and diagnostic criteria presently used by pathologists to report invasive placentation is inconsistent and does not reflect current knowledge of the pathogenesis of the disease or the needs of the clinical care team. A consensus panel was convened to recommend terminology and reporting elements unified across the spectrum of PAS specimens (i.e., delivered placenta, total or partial hysterectomy with or without extrauterine tissues, curetting for retained products of conception). The proposed nomenclature under the umbrella diagnosis of placenta accreta spectrum (PAS) replaces the traditional categorical terminology (placenta accreta, increta, percreta) with a descriptive grading system that parallels the guidelines endorsed by the International Federation of Gynaecology and Obstetrics (FIGO). In addition, the nomenclature for hysterectomy specimens is separated from that for delivered placentas. The goal for each element in the system of nomenclature was to provide diagnostic criteria and guidelines for expected use in clinical practice.

ACR Appropriateness Criteria® Placenta Accreta Spectrum Disorder.

Placenta accreta spectrum disorder (PASD) is the current terminology recommended by the International Federation of Obstetrics and Gynecology (FIGO) and should replace terms such as abnormally adherent/invasive placenta or morbidly adherent placenta. PASD refers to a variety of potential clinical complications, which may result from abnormal placental implantation. More specifically, placenta accreta refers to a defect in the decidua basalis where the chorionic villi adhere directly to the myometrium with trophoblastic invasion. Accurate antenatal diagnosis is needed to plan for an appropriate delivery strategy at an experienced center in order to reduce maternal and potential fetal morbidity and mortality. Obtaining radiologic and clinical data when PASD is first suspected can play a significant role in formulating an appropriate delivery strategy. Depending on the clinical risk factors and initial imaging findings, transabdominal ultrasound of the pregnant uterus with duplex Doppler and transvaginal ultrasound as needed are the most appropriate imaging procedures. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.