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Fetal cerebral magnetic resonance imaging, neurosonography and the brave new world of fetal medicine
No full textUltrasonography of the Prenatal Brain
No full textThe book contains up to date information on sonography of the fetal central nervous system. The normal embyology and sonography of the developing central nervous system throughout gestation is reviewed, as well the appearance, differential diagnosis and prognosis of the congenital anomalies arising from this area
Fetal cerebral magnetic resonance imaging, neurosonography and the brave new world of fetal medicine
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Sonographic examination of the fetal central nervous system: guidelines for performing the ‘basic examination’ and the ‘fetal neurosonogram’
No full textCentral nervous system (CNS) malformations are some of
the most common of all congenital abnormalities. Neural
tube defects are themost frequent CNS malformations and
amount to about 1–2 cases per 1000 births. The incidence
of intracranial abnormalities with an intact neural tube is
uncertain as probably most of these escape detection at
birth and only become manifest in later life. Long-term
follow-up studies suggest however that the incidence may
be as high as one in 100 births1.
Ultrasound has been used for nearly 30 years as the
main modality to help diagnose fetal CNS anomalies. The
scope of these guidelines is to review the technical aspects
of an optimized approach to the evaluation of the fetal
brain in surveys of fetal anatomy, that will be referred
to in this document as a basic examination. Detailed
evaluation of the fetal CNS (fetal neurosonogram) is also
possible but requires specific expertise and sophisticated
ultrasound machines. This type of examination, at
times complemented by three-dimensional ultrasound,
is indicated in pregnancies at increased risk of CNS
anomalies.
In recent years fetal magnetic resonance imaging (MRI)
has emerged as a promising new technique that may add
important information in selected cases and mainly after
20–22 weeks, although its advantage over ultrasound
remains debate
Cesarean Scar Pregnancy: Patient Counseling and Management
No full textThere is no universally agreed upon and adopted management protocol supported by professional societies in the United States or around the world for the treatment of cesarean scar pregnancy. There is a wide range of management options in the literature, and many of them can to lead to severe bleeding complications, which can result in loss of fertility or even maternal death. If inadequately managed, it can lead to untoward complications throughout all 3 trimesters of the pregnancy. Early detection of CSP has a paramount clinical importance
Natural history of Cesarean scar pregnancy on prenatal ultrasound: the crossover sign
No full textObjective: Advances in prenatal imaging techniques have led to an increase in the diagnosis of Cesarean scar pregnancy (CSP). However, antenatal counseling when CSP is diagnosed is challenging, and current evidence is derived mainly from small series reporting high rates of adverse maternal outcomes. The aim of this study was to ascertain the performance of prenatal ultrasound in predicting the natural history of CSP using a new sonographic sign, the crossover sign (COS). Methods: This was a retrospective analysis of early first-trimester (6–8 weeks' gestation) ultrasound images in women with morbidly adherent placenta (MAP) managed in the third trimester of pregnancy. The relationship between the gestational sac of the CSP, anterior uterine wall and Cesarean scar, defined as the COS, was analyzed to determine whether it could predict evolution in these cases. Odds ratios (ORs) were calculated and logistic regression analysis was performed to investigate the association between different types of COS (COS-1, COS-2+ or COS-2–) and the occurrence of MAP. Results: Sixty-eight pregnancies with MAP were included. The risk of placenta percreta was significantly higher in pregnancies with COS-1 than in those with COS-2 (OR, 6.67 (95% CI, 1.3–33.3)). When evaluating the two variants of COS-2 separately, the risk of placenta percreta was significantly higher in pregnancies with COS-1 vs COS-2+ (OR, 5.83 (95% CI, 1.1–30.2)) and this risk was even higher when comparing cases with COS-1 vs COS-2– (OR, 12.0 (95% CI, 1.9–75.7)). Logistic regression analysis showed that COS-1 was associated independently with severe forms of MAP, such as placenta percreta and increta (OR, 12.85 (95% CI, 2.0–84.0)), while COS-2+ was associated independently with placenta accreta (OR, 4.37 (95% CI, 1.1–17.0)). Conclusions: Ultrasound assessment of the relationship between the gestational sac of a CSP and the endometrial line (the COS) may help to determine whether a CSP will progress towards a less severe form of MAP, amenable to postnatal treatment, and successful pregnancy outcome. Large prospective studies are needed to confirm our findings and elucidate the natural history of this condition. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd
ISUOG Practice Guidelines (updated): sonographic examination of the fetal central nervous system. Part 2: performance of targeted neurosonography
No full textN.D
Reference ranges for fetal brain structures using magnetic resonance imaging: systematic review
Full text linkObjective
To evaluate the methodology of studies reporting reference ranges for fetal brain structures on magnetic resonance imaging (MRI).
Methods
MEDLINE, EMBASE, CINAHL and the Web of Science databases were searched electronically up to 31 December 2020 to identify studies investigating biometry and growth of the fetal brain and reporting reference ranges for brain structures using MRI. The primary aim was to evaluate the methodology of these studies. A list of 26 quality criteria divided into three domains, including ‘study design’, ‘statistical and reporting methods’ and ‘specific aspects relevant to MRI’, was developed and applied to evaluate the methodological appropriateness of each of the included studies. The overall quality score of a study, ranging between 0 and 26, was defined as the sum of scores awarded for each quality criterion and expressed as a percentage (the lower the percentage, the higher the risk of bias).
Results
Fifteen studies were included in this systematic review. The overall mean quality score of the studies evaluated was 48.7%. When focusing on each domain, the mean quality score was 42.0% for ‘study design’, 59.4% for ‘statistical and reporting methods’ and 33.3% for ‘specific aspects relevant to MRI’. For the ‘study design’ domain, sample size calculation and consecutive enrolment of women were the items found to be at the highest risk of bias. For the ‘statistical and reporting methods’ domain, the presence of regression equations for mean and SD for each measurement, the number of measurements taken for each variable and the presence of postnatal assessment information were the items found to be at the highest risk of bias. For the ‘specific aspects relevant to MRI’ domain, whole fetal brain assessment was not performed in any of the included studies and was therefore considered to be the item at the highest risk of bias.
Conclusions
Most of the previously published studies reporting fetal brain reference ranges on MRI are highly heterogeneous and have low-to-moderate quality in terms of methodology, which is similar to the findings reported for ultrasound studies
Extreme enhanced myometrial vascularity following cesarean scar pregnancy: a new diagnostic entity
No full textObjective: To define, illustrate and to follow-up the diagnosis, pathophysiology and treatment of a subset of the known enhanced myometrial vascularity (EMV): its extreme form, associated with cesarean scar pregnancies (CSP) and with some cases pf placenta accreta spectrum being at increased risk of significant bleeding complications. We also aim to provide guidance to the management of such cases. Material and methods: This is an IRB-approved retrospective observational study of thirteen patients with an extreme form of EMV complicating CSPs. Patient’s age, parity, number of cesarean deliveries, initial and time to negative serum hCG levels, primary and secondary diagnoses, blood flow peak systolic velocities, primary and secondary treatments, uterine artery embolization and outcomes were recorded. Results: Gestational ages ranged 6–11 weeks at initial presentation. Initial serum hCG was 20.0–102.48 mIU/L (mean 44.4 mIU/L). Diameter of EMV reached 20–75 mm (mean 46.8 mm). The mean peak systolic velocity (PSV) was 84.2 cm/s (range 46.7–118.0). Primary treatments were: systemic methotrexate (MTX) alone; D&C alone; MTX and D&C; local and systemic intra-gestational MTX injection; double cervical ripening balloon with systemic MTX; misoprostol and D&C; emergent UAE. UAE and hysterectomy were the two main secondary treatments in 10 women except 1 having a D&C after UAE, and in 1 the lesion regressed without secondary treatment. Mean time to nonpregnant hCG levels was 21–122 days (mean 67.2). Mean follow-up was 110.2 days (range 26–160). Ten women were treated with UAE, 6 had one, 3 had two embolizations. Two women had hysterectomies, one of these for persistent bleeding. Based upon the common denominators of the clinical and the US pictures, our definition of extreme EMV is sustained form of EMV associated with treated or untreated CSP, with peak systolic velocities of blood flow over 50 cm/s, slow return or plateauing serum hCG, with or without clinically significant vaginal bleeding, unresponsive to initial or secondary treatment requiring uterine artery embolization or hysterectomy. Conclusion: The EMV developing in the background of retained placental tissue associated with CSP differs following the normal regression of the physiologically re-modelled, dilated vascular bed from the faulty “disrepair” of the vessel wall in in treated or untreated CSPs. The “threatening” appearance of the above EMVs warranted the term “extreme”, creating their separate new sub-category.” Extreme forms of CSP-related EMV pose significant diagnostic and management challenges. Prompt recognition and intervention, the proactive use of UAE, can maximize the outcome of women affected by this “extreme” form of EMV enabling to preserve reproductive potential. Obstetricians, gynecologists and interventional radiologists should be aware of this form of severe vascular complication
Risk factors, histopathology and diagnostic accuracy in posterior placenta accreta spectrum disorders: systematic review and meta‐analysis
No full textObjectives
To elucidate the risk factor, histopathological correlations and diagnostic accuracy of prenatal imaging in detecting posterior PAS.
Methods
MEDLINE, Embase and CINAHL were searched. Inclusion criteria were women with posterior PAS confirmed either at surgery or histopathological analysis. The outcomes explored were: risk factor for posterior PAS, histopathological correlation, and diagnostic accuracy of ultrasound and MRI in detecting these anomalies.
Random‐effect meta‐analyses of proportions and summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR–) and diagnostic odds ratio (DOR) using the hierarchical summary receiver–operating characteristics (HSROC) model were used to analyse the data.
Results
20 studies were included. Placenta previa was present in 92.8% pregnancies complicated by posterior PAS, while 76.1% of women had a prior uterine surgery (11 studies, 53/ 88 women), mainly a CS or curettage. When considering the histopathological analysis of women affected by posterior PAS, 77.5% had placenta accrete (11 studies, 34/44 women) , 19.5% placenta increta (11 studies, 8/44 women) and 9.3% placenta percreta (11 studies, 2/44 women ). 56.4% of posterior PAS disorders were detected prenatally on ultrasound, while 46.7% were diagnosed only at birth (12 studies, 31 /63 women). When exploring the distribution of the classic ultrasound signs of PAS, placental lacunae were present in 39.0% (7 studies, 12/30 women), loss of the clear zone in 41.15% (7 studies, 13/30 women) and bladder wall interruption in 16.6% of women (7 studies, 4/30 women), while none of the included cases showed hypervascularization at the bladder wall interface. When assessing the role of MRI in detecting posterior PAS, 73.5% of cases were detected at prenatal MRI, while 26.5% were discovered only at the time of CS (11 studies, 26/32 women).
Conclusion
Placenta previa and prior uterine surgery represent the most commonly reported risk factors for posterior PAS. Ultrasound had a very low diagnostic accuracy in detecting these disorders prenatally
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