First-trimester ventriculomegaly in fetuses with callosal agenesis: Cause or association?

The sonographic findings in four fetuses presenting with ventriculomegaly at first-trimester ultrasound that were subsequently diagnosed as having agenesis of the corpus callosum (ACC) are described. The diagnosis of early ventriculomegaly was suspected subjectively by identification of increased cerebrospinal fluid within the lateral ventricles and confirmed by measuring choroid plexus-to-lateral ventricle length and area ratios. Subsequent scans revealed complete ACC in two cases and partial ACC in the other two. This report adds to the increasing evidence suggesting that first-trimester ventriculomegaly is a strong sonographic marker of underlying brain anomalies, including less evident malformations such as ACC. Detailed second-trimester fetal neurosonography in those women continuing their pregnancies should be performed.

Ultrasound findings and detection of fetal abnormalities before 11 weeks of gestation.

OBJECTIVE: To determine the proportion of major fetal structural abnormalities that can be detected before 11 gestational weeks. METHODS: We conducted a retrospective study of individual patient files at a tertiary provider of obstetric and gynecological ultrasound in Melbourne, Australia. All women who had a pre-cell-free DNA ultrasound with a crown-rump length of less than 45 mm and had one or more ultrasounds at a later gestation were included in the analysis. The primary outcome was the incidence of a fetal structural abnormality. RESULTS: A total of 3333 cases were included in the final analysis. Overall, 316 fetuses (9.5%) had a structural abnormality detected at any point throughout gestation, of which 86 were major structural abnormalities (2.6%). Sixteen fetal abnormalities were detected before 11 weeks of gestation, including 15 major abnormalities (17.4% of the major anomalies). All major fetal abnormalities detected before 11 gestational weeks were confirmed at later ultrasound examinations or the pregnancy did not continue (in four cases due to termination of pregnancy and in one case spontaneous miscarriage before first trimester morphology ultrasound). CONCLUSION: Detection of fetal abnormalities is possible before 11 weeks of gestation. Early suspicion is more likely in cases of major structural abnormalities.

Outcomes following the detection of fetal edema in early pregnancy prior to non-invasive prenatal testing.

OBJECTIVE: To investigate the incidence of structural and chromosomal abnormalities in cases of fetal edema on early ultrasound prior to non-invasive prenatal testing (NIPT). METHODS: A retrospective study of women undergoing pre-NIPT ultrasound with fetal crown-rump length (CRL) of 28 to 44 mm was conducted at a tertiary obstetric ultrasound clinic in Melbourne, Australia. Cases of reported fetal edema were included, and subclassified as isolated nuchal edema (>2.2 mm) or generalized edema/hydrops by two operators blinded to outcomes. RESULTS: We identified 104 cases of fetal edema. Nuchal edema and generalized edema were present in 40 (38.5%) and 64 (61.5%) cases, respectively. Relevant chromosomal anomalies were identified in 19.2% (20/104), occurring in 10.0% (4/40) of the nuchal edema and 25.0% (16/64) of the generalized edema/hydrops cases. Structural anomalies with normal karyotype occurred in four (3.8%) additional cases. Miscarriage occurred in four cases (3.8%) and termination of pregnancy in 18 cases (17.3%). Among cases that reached the 11 to 13+6 weeks ultrasound, the edema resolved in 81.9% and these cases had less adverse outcomes than those with NT≥3.5 mm (10.9% vs 76.5%, P < .001). CONCLUSIONS: Fetal edema in early pregnancy is associated with a high incidence of structural and/or chromosomal abnormalities; these rates increase with progressive severity.

The importance of ultrasound preceding cell-free DNA screening for fetal chromosomal abnormalities.

OBJECTIVE: This study aims to determine the incidence of ultrasound findings that may change clinical management on the day of blood-sampling for cell-free DNA (cfDNA) screening. METHODS: A retrospective study was conducted at a tertiary provider of obstetric and gynecological ultrasound in Melbourne, Australia. Individual patient files were reviewed and results were collated for maternal characteristics, pre-cfDNA ultrasound reports, results and test characteristics of both cfDNA and diagnostic testing, and genetic counselling notes. The primary outcome was a potential change in patient management due to findings detected on the pre-cfDNA ultrasound. RESULTS: Of 6250 pre-cfDNA ultrasounds, 6207 were included in analysis. Of these, 598 (9.6%) pregnancies had a finding on pre-cfDNA ultrasound that had the potential to change management. The reasons for this potential change in management were detection of gestational age below 10 weeks (245, 3.9%), miscarriage (175, 2.8%), demised twin (43, 0.7%), fetal edema (115, 1.9%) and major structural abnormalities (20, 0.3%). These findings were more common in patients of advanced maternal age and in spontaneous conceptions. CONCLUSIONS: An ultrasound prior to cfDNA screening has the potential to change clinical management in almost one in 10 women. The proportion is higher in older age groups and lower in IVF-conceived pregnancies.

Ultrasound Appearances of the Acrania-Anencephaly Sequence at 10 to 14 Weeks' Gestation.

OBJECTIVES: The acrania-anencephaly sequence is a lethal condition with a high detection rate in experienced hands after 10 weeks' gestation. However, earlier in gestation, many cases remain undetected. Different phenotypic appearances have been described and might help increase the detection rate in less experienced hands and also earlier in gestation. The purpose of this study was to assess interobserver reliability in classifying cases of the acrania-anencephaly sequence during first trimester in 6 different subtypes according to their ultrasound appearances. METHODS: This was a retrospective descriptive cohort study at 3 centers for fetal imaging. Each case was classified according to its phenotypic appearance by 2 independent operators as "bilobular," "cystic," "elongated," "irregular," "foreshortened," or "overhanging." Frequencies of each type are described, and interoperator agreement was assessed with the intraclass correlation coefficient. RESULTS: From the 88 included cases, the frequencies of the different subtypes classified as overhanging, elongated, bilobular, cystic, foreshortened, and irregular were 31%, 25%, 19%, 11%, 8%, and 6%, respectively. The interoperator reliability was good, with an intraclass correlation coefficient of 0.903 (95% confidence interval, 0.853-0.937; P < .001). CONCLUSIONS: Using different subtypes may improve the detection of the acrania-anencephaly sequence. An accurate early diagnosis could lead to timely, less traumatic, and safer management of affected pregnancies.

Cranial sonographic markers of fetal open spina bifida at 11 to 13 weeks of gestation.

OBJECTIVES: To compare the sonographic signs of spina bifida obtained on axial and sagittal views of the fetal head between 11 and 13+6 weeks of gestation. METHODS: This was a retrospective study including 27 cases of spina bifida and 1003 randomly selected controls. Indirect markers of spina bifida were evaluated on stored ultrasound images. Intracranial translucency (IT), ratio between the brainstem and the brainstem-occipital bone distance (BS/BSOB), and maxillo-occipital (MO) line were assessed on sagittal view, whereas biparietal diameter (BPD), BPD to abdominal circumference ratio (BPD/AC), and aqueduct to occipital bone (aqueduct of Sylvius [AoS]) distance were measured on the axial plane. Reference ranges were developed, and cases of spina bifida were examined in relation to the reference range. RESULTS: On the sagittal view, detection rates for IT below the fifth percentile, BS/BSOB above the 95th percentile, and an abnormal MO line were 52.3%, 96.3%, and 96.3%, respectively. On the axial view, detection rates for BPD, BPD/AC, and AoS below the fifth percentile were 66.7%, 70.4%, and 77.8%, respectively. CONCLUSION: The MO line and the BS/BSOB ratio appear to be the best indirect ultrasound markers of spina bifida and can be easily obtained during the routine first-trimester scan.

The gap between the aorta and the superior vena cava: A sonographic sign of persistent left superior vena cava and associated abnormalities.

OBJECTIVES: To assess the distance between the right superior vena cava (SVC) and the aorta in fetuses with bilateral superior vena cava as a possible sonographic marker for this. METHODS: This was a nested case-control study including 20 cases of bilateral SVC and 40 gestational age-matched controls. The distance between the right SVC and the aorta was measured at the level of the three-vessel trachea view in stored images, as well as the diameters of the aorta and the right SVC. RESULTS: The distance between the aorta and the right SVC was significantly larger in the cases of a left SVC compared with controls, P < .001. A distance of 2.0 mm or more was found in 70% of the cases and 5% of the controls, with a gestational-age adjusted area under the receiver-operating characteristics (ROC) curve for the diagnosis of left SVC of 0.93 (95% CI 0.87-0.99). The aorta and the right SVC were significantly smaller in cases compared with controls, and there was a significant association with other cardiac and extracardiac abnormalities amongst cases of persistent left SVC. CONCLUSION: An increased distance between the aorta and the right SVC is associated with the diagnosis of bilateral SVC.

Maxillo-occipital line: a sonographic marker for screening of open spina bifida in the first trimester of pregnancy.

Objective: To describe a new first-trimester sonographic landmark the maxillo-occipital line which may be useful for early screening of open spina bifida.Methods: Maxillo-occipital line was prospectively evaluated in 100 low-risk pregnancies at the time of first-trimester sonographic screening examination between 11 and 13 + 6 weeks' gestation. All the pregnant women subsequently had a normal second-trimester scan and normal outcomes. Midsagittal brain images of 14 fetuses with known diagnosis of open spina bifida were evaluated retrospectively to review the maxillo-occipital line.Results: None of the 100 fetuses evaluated prospectively with the maxillo-occipital line below the junction of the midbrain and brain stem were affected by open spina bifida. The aqueduct of Silvius to occiput distance measurement was not obtained in five cases. In all, 14 cases with a diagnosis of open spina bifida, the junction between the midbrain and brain stem, were below the maxilla-occipital line.Conclusion: Maxillo-occipital line is an easy addition to the evaluation of first-trimester screening of open spina bifida. Further studies are needed to determine the false-positive and false-negative rates of this technique.

How to perform a sonographic morphological assessment of the fetus at 11-14 weeks of gestation.

INTRODUCTION: First-trimester ultrasound is widely accepted as part of standard care in many countries. With improvements in equipment, expertise and increasing number of technical studies describing imaging techniques, the detection rate for major fetal anomalies in the first trimester continues to rise and can be as high as 60% in high-risk populations. METHODS: We set out to create a systematic pictorial guide for trained ultrasound providers to describe the common anatomical structures that are identifiable in the first trimester with provided images. In addition to normal anatomical structures, a number of anomalies with high detection rates are listed. CONCLUSION: A large proportion of the major fetal abnormalities can be detected in the first trimester. A systematic approach is essential to ensure that anomalies are equally likely to be detected for patients of any risk background.

Guidelines for the performance of the first trimester ultrasound.

The purpose of this document is to guide ultrasound practitioners in providing accurate information on the assessment of gestational age, viability and fetal development in the first trimester. In the presence of twins and higher order multiple pregnancies, it is also intended to assess chorionicity and amnionicity which have implications for risk assessment and continuing antenatal care. This guideline has been adopted by the ASUM Council and is applicable to all ultrasound practitioners.

Three-dimensional imaging of the uterus: The value of the coronal plane.

Advent in three-dimensional (3D) imaging technology has seen 3D ultrasound establish itself as a useful adjunct complementary to traditional two-dimensional imaging of the female pelvis. This advantage largely arises from its ability to reconstruct the coronal plane of the uterus, which allows further delineation of many gynecological disorders. 3D imaging of the uterus is now the preferred imaging modality for assessing congenital uterine anomalies and intrauterine device localization. Newer indications include the diagnosis of adenomyosis. It can also add invaluable information to delineate other endometrial and myometrial pathology such as fibroids and endometrial polyps.