Crystal Vue technique for imaging fetal spine and ribs

Three-dimensional volume rendering ultrasound for assessing placenta accreta spectrum severity and discriminating it from simple scar dehiscence

BACKGROUND

Prenatal ultrasound discrimination between placenta accreta spectrum and scar dehiscence with underlying nonadherent placenta is challenging both prenatally and intraoperatively, which often leads to overtreatment. In addition, accurate prenatal prediction of surgical difficulty and morbidity in placenta accreta spectrum is difficult, which precludes appropriate multidisciplinary planning. The advent of advanced 3-dimensional volume rendering and contrast enhancement techniques in modern ultrasound systems provides a comprehensive prenatal assessment, revealing details that are not discernible in traditional 2-dimensional imaging.

OBJECTIVE

This study aimed to evaluate the use of 3-dimensional volume rendering ultrasound techniques in determining the severity of placenta accreta spectrum and distinguishing between placenta accreta spectrum and scar dehiscence with underlying nonadherent placenta.

STUDY DESIGN

A prospective, cohort study was conducted between July 2022 and July 2023 in the fetal medicine unit of Dr Soetomo Academic General Hospital, Surabaya, Indonesia. All pregnant individuals with anterior low-lying placenta or placenta previa with a previous caesarean section who were referred with suspicion of placenta accreta spectrum were consented and screened using the standardised 2-dimensional and Doppler ultrasound imaging. Additional 3-dimensional volumes were obtained from the sagittal section of the uterus with a filled urinary bladder. These were analyzed by rotating the region of interest to be perpendicular to the uterovesical interface. The primary outcomes were the clinical and histologic severity in the cases of placenta accreta spectrum and correct diagnosis of dehiscence with nonadherent placenta underneath. The strength of association between ultrasound and clinical outcomes was determined. Multivariate logistic regression analyses and diagnostic testing of accuracy were used to analyze the data.

RESULTS

A total of 70 patients (56 with placenta accreta spectrum and 14 with scar dehiscence) were included in the analysis. Multivariate logistic regression of all 2-dimensional and 3-dimensional signs revealed the 3-dimensional loss of clear zone (P<.001) and the presence of bridging vessels on 2-dimensional Doppler ultrasound (P=.027) as excellent predictors in differentiating scar dehiscence and placenta accreta spectrum. The 3-dimensional loss of clear zone demonstrated a high diagnostic accuracy with an area under the curve of 0.911 (95% confidence interval, 0.819-1.002), with a sensitivity of 89.3% (95% confidence interval, 78.1-95.97%) and specificity of 92.9% (95% confidence interval, 66.1-99.8%). The presence of bridging vessels on 2-dimensional Doppler demonstrated an area under the curve of 0.848 (95% confidence interval, 0.714-0.982) with a sensitivity of 91.1% (95% confidence interval, 80.4-97.0%) and specificity of 78.6% (95% confidence interval, 49.2-95.3%). A subgroup analysis among the placenta accreta spectrum group revealed that the presence of a 3-dimensional disrupted bladder serosa with obliteration of the vesicouterine space was associated with vesicouterine adherence (P<.001).

CONCLUSION

Three-dimensional volume rendering ultrasound is a promising tool for effective discrimination between scar dehiscence with underlying nonadherent placenta and placenta accreta spectrum. It also shows potential in predicting the clinical severity with urinary bladder involvement in cases of placenta accreta spectrum.

Cleft palate in fetuses: feasibility of early diagnosis by Crystal and Realistic Vue rendering 3D ultrasound technology in the first trimester

Objectives

This study aimed to evaluate the feasibility of direct visualization of a normal fetal palate and detect cleft palate in the first trimester with a novel three-dimensional ultrasound (3D US) technique, Crystal and Realistic Vue (CRV) rendering technology.

Methods

Two-dimensional (2D) images and 3D volumes of healthy and cleft palate fetuses at 11-13⁺⁶ weeks were obtained prospectively. 2D ultrasound views included the coronal view of the retronasal triangle and the midsagittal view of the face. 3D-CRV views were analyzed by multiplanar mode display. The pregnancy outcomes of all fetuses were determined during the follow-up period.

Results

In our study, 124 fetuses were recruited, including 100 healthy fetuses and 24 cleft palate fetuses. The cleft palate with lip was observed in 23 fetuses (bilateral in 15, unilateral in 6, median in 2), and one cleft palate was only found in the abnormal group. The bilateral (n = 12) and median (n = 2) cleft palates with lips and the cleft palate alone (n = 1) were associated with other anatomical or chromosomal abnormalities, and one unilateral cleft palate with cleft lip had concomitant NT thickening. In the cleft palate fetus group, 16 fetuses suffered intrauterine death, which was associated with other structural or chromosomal abnormalities in 14 fetuses, seven cases were terminated after consultation, and one was delivered at term. The coronal view of the retronasal triangle and the midsagittal view was easily obtained in all fetuses. 3D-CRV images of palatal parts were clearly obtained in all cases. Unilateral, bilateral, and median cleft palates with cleft lips were visually demonstrated and classified by the 3D-CRV technique.

Conclusion

It is feasible to identify the palate by 3D-CRV in the first trimester in both healthy and cleft palate fetuses. Together with 2D ultrasonography as a complementary diagnostic tool, 3D-CRV is helpful in classifying the cleft palate with a reasonable degree of certainty.

Evaluation of the Tramline Sign in the Prediction of Placenta Accreta Spectrum and Perioperative Outcomes in Anterior Placenta Previa

PURPOSE

 To evaluate perioperative outcomes and the prognostic role of the tramline sign in a cohort of women with anterior placenta previa.

MATERIALS AND METHODS

 Retrospective analysis of 3D ultrasound volumes from women with anterior placenta previa who underwent ultrasound examination beyond 32 weeks. 3D and 3D color volumes were obtained from a sagittal section of the uterus bisecting a partially full bladder and processed using Crystal Vue and Crystal Vue Flow rendering to look for the "tramline sign". "Partial obliteration" was defined as a loss of some or part of the uterine-serosal interface and "full obliteration" as when both interfaces were interrupted. Postnatal ascertainment of placenta accreta spectrum (PAS) was confirmed by findings recorded intraoperatively or on a pathology report.

RESULTS

 65 cases were included. The tramline sign was "partially" (17) or "fully" (19) obliterated in 36 cases (55.4 %), and present in 29 (44.6 %). Obliteration was associated with earlier gestational age at delivery (35 + 1 (26 + 3-38 + 3) vs. 36 + 4 (25 + 3-38 + 0) weeks, p = 0.005), greater estimated blood loss (800 (400-11 000) vs. 600 (300-2100) mls, p = 0.003), longer operative time (155 (60-240) vs. 54 (25-80) minutes, p < 0.001), higher rate of hysterectomy (97.2 % vs. 0.0 %, p < 0.001), longer postoperative admission (7 (3-19) vs. 3 (1-5) days, p < 0.001) and a 100 % rate of postnatal diagnosis of PAS. The finding of an "obliterated" tramline sign identified all women that required hysterectomy and all cases of PAS.

CONCLUSION

 A "partially or fully obliterated" tramline sign is strongly associated with indicators of operative complexity, the postnatal confirmation of PAS, and the need for peripartum hysterectomy.

Imaging fetal anatomy

Due to advancements in ultrasound techniques, the focus of antenatal ultrasound screening is moving towards the first trimester of pregnancy. The early first trimester however remains in part, a 'black box', due to the size of the developing embryo and the limitations of contemporary scanning techniques. Therefore there is a need for images of early anatomical developmental to improve our understanding of this area. By using new imaging techniques, we can not only obtain better images to further our knowledge of early embryonic development, but clear images of embryonic and fetal development can also be used in training for e.g. sonographers and fetal surgeons, or to educate parents expecting a child with a fetal anomaly. The aim of this review is to provide an overview of the past, present and future techniques used to capture images of the developing human embryo and fetus and provide the reader newest insights in upcoming and promising imaging techniques. The reader is taken from the earliest drawings of da Vinci, along the advancements in the fields of in utero ultrasound and MR imaging techniques towards high-resolution ex utero imaging using Micro-CT and ultra-high field MRI. Finally, a future perspective is given about the use of artificial intelligence in ultrasound and new potential imaging techniques such as synchrotron radiation-based CT to increase our knowledge regarding human development.

Exploring copy number variants in deceased fetuses and neonates with abnormal vertebral patterns and cervical ribs

Background

Cervical patterning abnormalities are rare in the general population, but one variant, cervical ribs, is particularly common in deceased fetuses and neonates. The discrepancy between the incidence in the general population and early mortality is likely due to indirect selection against cervical ribs. The cause for the co‐occurrence of cervical ribs and adverse outcome remains unidentified. Copy number variations resulting in gain or loss of specific genes involved in development and patterning could play a causative role.

Methods

Radiographs of 374 deceased fetuses and infants, including terminations of pregnancies, stillbirths and neonatal deaths, were assessed. Copy number profiles of 265 patients were determined using single nucleotide polymorphism array.

Results

274/374 patients (73.3%) had an abnormal vertebral pattern, which was associated with congenital abnormalities. Cervical ribs were present in 188/374 (50.3%) and were more common in stillbirths (69/128 [53.9%]) and terminations of pregnancies (101/188 [53.7%]), compared to live births (18/58, 31.0%). Large (likely) deleterious copy number variants and aneuploidies were prevalent in these patients. None of the rare copy number variants were recurrent or overlapped with candidate genes for vertebral patterning.

Conclusions

The large variety of copy number variants in deceased fetuses and neonates with similar abnormalities of the vertebral pattern probably reflects the etiological heterogeneity of vertebral patterning abnormalities. This genetic heterogeneity corresponds with the hypothesis that cervical ribs can be regarded as a sign of disruption of critical, highly interactive stages of embryogenesis. The vertebral pattern can probably provide valuable information regarding fetal and neonatal outcome.

Sonographic demonstration of fetal esophagus using three-dimensional ultrasound imaging

OBJECTIVE

To evaluate the feasibility of antenatal direct visualization of normal and abnormal fetal esophagus using three-dimensional ultrasound (3D-US) with Crystal Vue rendering technology.

METHODS

Between February and April 2018, 3D-US volumes were collected from a non-consecutive series of singleton pregnancies, referred for clinically indicated detailed prenatal ultrasound at 19-28 weeks' gestation to one of two fetal medicine units in Italy. 3D volumes were acquired from a midsagittal section of the fetal thorax and upper abdomen with the fetus lying in supine position. Postprocessing with multiplanar mode was applied to orientate the volume and identify the esophagus. The region of interest was angled by approximately 30° to the spine and its thickness was adjusted in order to optimize visualization of the intrathoracic and intra-abdominal course of the esophagus. Crystal Vue software was used for image rendering of the fetal trunk in the coronal plane. Postnatal follow-up was available in all cases.

RESULTS

During the study period, 91 pregnancies met the inclusion criteria and were recruited. The study cohort included two pregnancies with suspicion of esophageal atresia due to suboptimal visualization of the stomach. Of the 89 cases with normal stomach on two-dimensional (2D) imaging, 3D-US with Crystal Vue rendering technology allowed direct evaluation of the whole course of the esophagus in 74 (83.1%). In the two cases with small or absent stomach bubble on 2D imaging, esophageal atresia was demonstrated antenatally on 3D Crystal Vue imaging and was confirmed postnatally. The mean time required for offline postprocessing and visualization of the esophageal anatomy was 4 min.

CONCLUSIONS

Using 3D-US with Crystal Vue rendering, it is possible to visualize antenatally the normal fetal esophagus and demonstrate presence of esophageal atresia. This should facilitate prenatal counseling and management of cases with suspected esophageal atresia. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

How to obtain diagnostic planes of the fetal central nervous system using three-dimensional ultrasound and a context-preserving rendering technology

The antenatal evaluation of the fetal central nervous system (CNS) is among the most difficult tasks of prenatal ultrasound (US), requiring technical skills in relation to ultrasound and image acquisition as well as knowledge of CNS anatomy and how this changes with gestation. According to the International Guidelines for fetal neurosonology, the basic assessment of fetal CNS is most frequently performed on the axial planes, whereas the coronal and sagittal planes are required for the multiplanar evaluation of the CNS within the context of fetal neurosonology. It can be even more technically challenging to obtain "nonaxial" views with 2-dimensional (2D) US. The modality of 3-dimensional (3D) US has been suggested as a panacea to overcome the technical difficulties of achieving nonaxial views. The lack of familiarity of most sonologists with the use of 3D US and its related processing techniques may preclude its use even where it could play an important role in complementing antenatal 2D US assessment. Furthermore, once a 3D volume has been acquired, proprietary software allows it to be processed in different ways, leading to multiple ways of displaying and analyzing the same anatomical imaging or plane. These are difficult to learn and time consuming in the absence of specific training. In this article, we describe the key steps for volume acquisition of a 3D US volume, manipulation, and processing with reference to images of the fetal CNS, using a newly developed context-preserving rendering technique.

New three-dimensional/four-dimensional volume rendering imaging software for detecting the abnormally invasive placenta

OBJECTIVE

This study aimed to determine the role of three-dimensional (3D)/four-dimensional (4D) volume rendering ultrasound (VRU) in the diagnosis of abnormally invasive placenta (AIP).

MATERIALS AND METHODS

Twelve consecutive patients strongly suspected of having AIP on the basis of conventional ultrasound (US) and clinical history performed between September 2016 and December 2016 in the main tertiary referral hospital in Surabaya, East Java were included in this prospective observational study. A Samsung WS 80A Elite US scanner with a 3D/4D "crystal vue" and "realistic vue" volume rendering mode was used to establish the diagnosis of AIP and evaluate the site, and depth of placental invasion. The VRU images were compared with the intraoperative findings.

RESULTS

Using this novel US technique, all cases of suspected AIP were subsequently confirmed during surgery. Importantly, the new US technique provided a correct diagnosis of the degree of invasion in 11 out of these 12 suspected AIP cases: 5/5 for placenta percreta, 3/3 for placenta increta, and 2/3 for placenta accreta; one patient was misdiagnosed in terms of the degree of placenta accreta, and one patient had normal implantation).

CONCLUSION

This new software of 3D/4D VRU represents a promising technique for the preoperative diagnosis and staging of AIP.

Three-dimensional ultrasonography by means of HDlive rendering in the first trimester of pregnancy: A pictorial review

Our objective was to describe early embryo/fetus anatomy and abnormalities provided by three and four-dimensional (3D/4D) ultrasound using HDlive rendering technology in the first trimester of pregnancy. Normal and pathologic embryonic and fetal volume data set with postprocessing using HDlive rendering mode. Virtual fetoscopic imaging of the normal and pathologic fetus even at early stage of development with increasing maternal-fetal bonding process. HDlive represents a novel and valuable lightening system for 3D/4D ultrasound application that may aid the prenatal interpretation of early congenital malformations although limitations and cautions are still needed for inclusion in obstetric clinical practice.