Double sac sign and intradecidual sign in early pregnancy: interobserver reliability and frequency of occurrence

A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations

The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed.

A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations

The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed. © RSNA and Elsevier, 2024 Supplemental material is available for this article. This article is a simultaneous joint publication in Radiology and American Journal of Obstetrics & Gynecology. All rights reserved. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Either version may be used in citing this article. See also the editorial by Scoutt and Norton in this issue.

The Confounding Ultrasound Diagnosis of Ectopic Pregnancy: Lessons From Peer Learning

ABSTRACT

As the treatment of ectopic pregnancy (EP) has shifted increasingly to medical therapies, the ultrasound (US) diagnosis of EP must necessarily favor specificity over sensitivity. Our review of peer learning cases of EP and early intrauterine pregnancies found several types of pitfalls and problems, which will be described in this essay. These issues include the following: differentiation of tubal EP from a corpus luteum by echogenicity relative to ovarian parenchyma, push technique, and claw sign; how to distinguish interstitial EP from eccentrically located intrauterine pregnancies (angular); use of trophoblastic flow in abnormal intrauterine locations to help identify cesarean scar or cervical implantations; recognition that hemoperitoneum without visualized EP may be due to EP or hemorrhagic cyst; and that distinguishing an abortion in progress from a pregnancy of unknown location may not always be possible and requires clinical follow-up. This essay will also illustrate the consensus terminology that our radiology department has developed in conjunction with our obstetrics and gynecology colleagues to communicate clear diagnoses and reduce the risk of misdiagnosis and adverse outcomes.

"Pseudogestational Sac" and Other 1980s-Era Concepts in Early First-Trimester Ultrasound: Are They Still Relevant Today?

OBJECTIVES

To determine whether an intrauterine round or oval fluid collection ("saclike structure") can prove to be either an intrauterine pregnancy or intrauterine fluid in conjunction with an ectopic pregnancy (sometimes termed "pseudogestational sac") and whether ultrasound features, including the presence or absence of an echogenic rim, "double sac sign" (DSS), or "intradecidual sign" (IDS), are helpful for establishing the diagnosis or predicting the prognosis.

METHODS

We identified all sonograms obtained from women with positive serum human chorionic gonadotropin results at our institution between January 1, 2012, and June 30, 2018, meeting the following criteria: presence of an intrauterine saclike structure without a yolk sac or embryo; no extraovarian adnexal mass; and follow-up information identifying the location of the pregnancy as intrauterine or ectopic. Study authors reviewed sonograms in all cases and recorded the following information: presence or absence of each of an echogenic rim around the collection, a DSS, and an IDS, as well as the mean sac diameter. The indications for the initial ultrasound examinations were recorded.

RESULTS

A total of 649 sonograms met the inclusion criteria. Of these, 598 fluid collections showed an echogenic rim, 182 a DSS, and 347 an IDS (findings not mutually exclusive). In all 649 cases, a subsequent sonogram or other clinical follow-up confirmed that the patient had an intrauterine pregnancy. That is, none of the fluid collections proved to be a pseudogestational sac. In total, 41.2% were live at the end of the first trimester, and 58.8% miscarried. The prognosis was better in cases with, compared to without, an IDS (P = .01, χ² ), but no ultrasound feature was clinically useful for ruling in or excluding a good prognosis.

CONCLUSIONS

In a woman with positive human chorionic gonadotropin results and no extraovarian adnexal mass, the ultrasound finding of an intrauterine saclike structure is virtually certain to be a gestational sac. Ultrasound features of the structure are of no diagnostic or clinically useful prognostic value. Concepts introduced 30 to 40 years ago when ultrasound equipment had far lower resolution than currently, including a DDS, an IDS, and a pseudogestational sac, have no role today in assessing early pregnancy.

Pseudoembryo associated with pseudogestational sac: A novel sonographic finding in ectopic pregnancy

In this case report, we present a case of a hitherto undescribed "pseudoembryo" appearance in a fluid-filled endometrial cavity in ectopic pregnancy.

Knowledge of this sonographic finding is clinically important, since the presence of a "pseudoembryo" could lead to the misidentification of a pseudogestational sac as an intrauterine pregnancy in the setting of ectopic pregnancy.

This paper discuss reviews the pseudogestational sac and imaging findings which differentiate it from a true intrauterine gestation.

ACOG Practice Bulletin No. 193: Tubal Ectopic Pregnancy

Ectopic pregnancy is defined as a pregnancy that occurs outside of the uterine cavity. The most common site of ectopic pregnancy is the fallopian tube. Most cases of tubal ectopic pregnancy that are detected early can be treated successfully either with minimally invasive surgery or with medical management using methotrexate. However, tubal ectopic pregnancy in an unstable patient is a medical emergency that requires prompt surgical intervention. The purpose of this document is to review information on the current understanding of tubal ectopic pregnancy and to provide guidelines for timely diagnosis and management that are consistent with the best available scientific evidence.

Ultrasound of the First Trimester

Ultrasound is the imaging study of choice for detection and full characterization of early pregnancies based on its accuracy, low cost, safety profile, and abundant availability. This article reviews the goals and utility of first-trimester ultrasound in gestation localization, viability determination, and abnormal pregnancies, including ectopic implantation, retained products, and molar pregnancy.

Pitfalls and tips in the diagnosis of ectopic pregnancy

Women of reproductive age with pelvic pain, vaginal bleeding, and a positive pregnancy test often require evaluation with pelvic ultrasound. In these situations, the primary role of pelvic ultrasound is to differentiate an ectopic pregnancy from either a normal or abnormal intrauterine pregnancy. While an accurately performed and interpreted pelvic ultrasound results in rapid diagnosis and management, numerous diagnostic pitfalls can lead to negative outcomes. Therefore, familiarity with the appropriate laboratory tests, sonographic technique, and imaging features of ectopic pregnancy is essential for all radiologists. We present a review of ectopic pregnancy cases from our institution with attention to common pitfalls and troubleshooting tips for physicians who perform and interpret pelvic ultrasounds. We also present recently published literature to aid in the management of first trimester pregnancy.

Normal and Abnormal US Findings in Early First-Trimester Pregnancy: Review of the Society of Radiologists in Ultrasound 2012 Consensus Panel Recommendations

Since being introduced more than 30 years ago, endovaginal ultrasonography (US) and quantitative testing of serum levels of the beta subunit of human chorionic gonadotropin have become the standard means of establishing the presence of normal intrauterine pregnancy (IUP), failed IUP, and ectopic pregnancy. Appropriate use of these powerful tools requires clear, standardized interpretations based on conservative criteria to protect both the pregnancy and the mother. Since diagnoses are assigned earlier and available medical treatments for ectopic pregnancy and failed IUP are expanding, emphasis must carefully shift toward watchful waiting when the mother is clinically stable and a definitive location for the pregnancy cannot be established with US. To this end and to prevent inadvertent harm to early normal pregnancies, the Society of Radiologists in Ultrasound convened a consensus panel of radiologists, obstetricians, and emergency medicine physicians in 2012 with the goal of reviewing current literature and clinical practices and formulating modern criteria and terminology for the various first-trimester outcomes.

Diagnostic Methods of Ectopic Pregnancy and Early Pregnancy Loss: a Review of the Literature

This review article presents recent evidence on early pregnancy loss and ectopic pregnancy. In the light of recent evidence, the β-hCG discriminatory zone may be extended in clinically stable cases without evidence of bleeding. A possible cut-off is 4300 mIU/ml, which corresponds to when a sonographer should detect an intrauterine pregnancy. Embryonic demise can be confirmed when a transvaginal ultrasound finding shows no heartbeat in an embryo of more than 7 mm CRL, no embryo in a gestational sac having a mean sac diameter of more than 25 mm, or no appearance of an embryo within 7-10 days after the primary examination. These are considered definitive signs of embryonic demise. Suggestive signs of embryonic demise require closer monitoring of the pregnancy.

Termination of pregnancy at very early gestation without visible yolk sac on ultrasound

INTRODUCTION

Requests for termination of pregnancy (TOP) at very early gestation (≤6 weeks) can prove challenging for abortion services as the ultrasound feature usually accepted as definitive evidence of an intrauterine pregnancy (IUP), the presence of a yolk sac within a gestational sac, may not yet be evident. In 2011 the Edinburgh TOP service introduced a protocol permitting women to proceed to treatment without further investigations provided that ultrasound showed the features of an eccentrically placed gestational sac (≥3 mm) with a decidual reaction, and there were no signs, symptoms or risk factors for ectopic pregnancy.

METHODS

A retrospective audit was conducted of outcomes of women presenting for TOP at ≤6 weeks' gestation over a 2-year period using the hospital computerised database.

RESULTS

A total of 1155 women presented for TOP with an ultrasound gestational age of ≤6 weeks. Of these, 1030 (89%) had ultrasound evidence of a yolk sac. Eighty-seven women (7.5%) had an eccentrically placed gestational sac with a decidual reaction. All 87 women fulfilled our criteria to proceed to medical TOP, and 66 did so. In the remaining 21 cases, further investigations were performed before they proceeded to medical TOP. Two (0.17%) medical TOPs failed, both in women whose initial ultrasound had shown a yolk sac.

CONCLUSION

Women with ultrasound features consistent with a very early IUP (≥3 mm eccentrically placed gestational sac with a decidual reaction) and without signs, symptoms or risk factors for ectopic pregnancy can proceed directly to medical TOP without the need for delay for further ultrasonography.

Ultrasound evaluation of the first trimester

Ultrasound is a valuable diagnostic test throughout the first trimester of pregnancy. Early in this trimester, it is used to distinguish between normal intrauterine, failed intrauterine, and ectopic pregnancies. Later it can be used with maternal blood tests to screen for trisomy 21 and other forms of aneuploidy, and in some centers to assess fetal anatomy and diagnose structural anomalies. First trimester sonography is also useful for accurate assessment of gestational age. This article reviews these applications, the approach to establishing diagnoses, and ways to avoid diagnostic mistakes that can lead to serious errors in patient management and adverse pregnancy outcome.