posterior fossa first trimester

OBJECTIVES: To measure the ratio of choroid plexus (CP) size to head size in normal fetuses and to compare it to that in fetuses with open spina bifida (OSB) and quantify the subjective sign of a 'dry brain'. METHODS: This was a retrospective study of ultrasound images, obtained during first-trimester screening between 11 and 13 weeks of gestation, from 34 fetuses with OSB and 160 normal fetuses. From the hospital databases, we retrieved images of the fetal head in the transventricular axial plane...

OBJECTIVE: To demonstrate sonographic detectable abnormalities of the posterior fossa in fetuses with a crown-rump length of 45-84 mm in high-risk pregnancies. METHODS: This was a prospective, observational study including 47 fetuses with known outcome, whose mothers attended our centers for first trimester tests and showed an abnormal first trimester ultrasound scan. In these fetuses, we examined transvaginal acquired three-dimensional volume blocks for abnormalities of the fetal posterior fossa...

OBJECTIVE: To report reference ranges for fetal cerebral posterior fossa measurements and to describe the sonographic findings, karyotype results, and pregnancy outcomes in fetuses presenting with cystic posterior fossa (CPF) in the first trimester of pregnancy. METHODS: Two groups of patients undergoing first-trimester sonographic screening at 11-13 weeks' gestation were studied. The first (control group) consisted of 253 consecutive fetuses with normal posterior fossa, in which the brainstem (BS), fourth ventricle, cisterna magna, and BS-occipital bone (BS-OB) diameter were prospectively measured and the BS/BS-OB diameter ratio was calculated...

BACKGROUND: Fetal magnetic resonance imaging (MRI), mainly performed at standard field strength, plays a role in the classification of posterior fossa malformations. In the context of early second-trimester screening, upward rotation of the cerebellar vermis per se is usually compatible with a more favorable outcome than Dandy-Walker malformation and profound vermian hypoplasia. Delayed fenestration of Blake's pouch may either mimic vermian hypoplasia by compression or be associated with it in individual cases...

INTRODUCTION: Isotretinoin, a synthetic derivative of vitamin A, is one of the most potent human teratogens, and is mainly utilized for the treatment of severe recalcitrant nodular acne. Retinoic acid embryopathy is well defined in the literature. CASE REPORT: The mother was referred for a fetal posterior fossa abnormality, first detected at 20 weeks of gestation. The mother used isotretinoin until 18 weeks gestation. Ultrasound examination revealed hypertelorism, cerebellar hypoplasia, vermian agenesis, truncus arteriosus, anotia, thymic aplasia, corpus callosum hypoplasia...

INTRODUCTION: Blake's pouch cyst (BPC) represents an abnormal development of the posterior membranous area of the fetal brain. MATERIAL AND METHODS: Two- and three-dimensional ultrasound with Cristal and Realistic Vue were used to characterized the early prenatal diagnosis. RESULTS: At 9 weeks and 5 days a ballooning in the posterior fossa and resulting in an enlarged intracranial translucency (IT) was detected by 3D ultrasound using Cristal Vue in "inversion" mode and Cristal plus Realistic Vue...

PURPOSE: To compare visualization of first trimester fetal anatomic transvaginal ultrasound (TVUS) to the second trimester transabdominal anatomic ultrasound (TAU) in normal weight and obese patients. MATERIALS AND METHODS: In a prospective cross-sectional study design, 25 women underwent a TVUS between 12 and 14 weeks, and a TAU at 18-22 weeks. For each anatomic structure, the percentage of patients achieving optimal visualization was recorded. Risk ratios for visualizing a structure in the second trimester versus the first were calculated...

Accurate and timely prenatal diagnosis of spina bifida (SB) is a major goal of modern antenatal care. Prenatal screening for open SB should be first performed at the time of routine first-trimester ultrasound by examining the posterior fossa for obliteration or non-visualization of the fourth ventricle ("intracranial translucency") and cisterna magna. The second step of screening is the second-trimester anatomy scan, at which time the features of the Chiari type II malformation should be looked for, including ventriculomegaly, scalloping of the frontal bones ("lemon" sign), and backward and caudal displacement of the cerebellar vermis with obliteration of the cisterna magna ("banana" sign)...

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The objective of this study was to test three measurements: brain stem (BS), intracranial translucency (IT) and brain stem to occipital bone distance (BSOB), as well as one landmark: cisterna magna (CM) visibility, for early diagnosis of open spina bifida (OSB) in a low risk population. A prospective observational study was undertaken in a university hospital. A sample of 1479 women consented to participate between 20 September 2013 and 30 June 2015. Measurements were performed from the mid-sagittal view, as is routinely used for nuchal thickness assessment...

OBJECTIVE: To assess non-visualization of the choroid plexus of the fourth ventricle (CP-4V) as a simple, qualitative and reproducible first-trimester ultrasound feature of the posterior fossa for the prediction of central nervous system (CNS) anomalies and chromosomal defects. METHODS: First-trimester three-dimensional ultrasound datasets of the fetal brain were obtained prospectively from 65 consecutive normal singletons and retrospectively from 27 fetuses identified as having an abnormal posterior fossa on first-trimester ultrasound examination, and randomly combined to form the final study group...

Both in routine diagnostics and detailed, highly specialized workups, major advances have been observed in many areas of ultrasound due to an increase in expertise and improved technology in recent years. This is particularly true in the case of fetal neurosonography 1 2 3 4. Malformations of the CNS together with fetal heart defects are among the most common congenital anomalies. From the embryonic phase to the late third trimester, the CNS undergoes extensive development and maturation processes. The diagnosis of CNS anomalies is therefore primarily dependent on the time at which the examination is performed and the experience of the examiner...

INTRODUCTION: The antenatal diagnosis of open spina bifida (OSB), a neural tube defect, is predominantly made at the second trimester morphology scan by ultrasound detection of structural abnormalities resulting from the associated Chiari II malformation. Evidence has emerged suggesting that these structural abnormalities can be detected earlier, by examination of the posterior fossa as part of the first trimester nuchal translucency scan. In particular, absence of the intra-cranial translucency (IT) of the fourth ventricle has shown promise as a diagnostic marker of OSB, although the sensitivity and specificity of this finding varies widely in the literature...

OBJECTIVE: To describe the pattern and progression of central nervous system (CNS) lesions in microcephalic fetuses with suspected Zika virus (ZIKV) infection. METHODS: In this prospective study in Salvador, Brazil, we analyzed fetuses diagnosed with microcephaly and suspected ZIKV infection after a routine primary care ultrasound scan between July 2015 and February 2016 raised suspicion of fetal microcephaly. The pregnancies were followed with serial ultrasound scans until delivery at one of the three main referral centers for fetal abnormalities in Salvador, Brazil...

OBJECTIVE: To describe the sonographic appearance and temporal changes of the structures of the posterior cranial fossa in fetuses at a crown-rump length (CRL) between 45 and 84 mm in transvaginal acquired three-dimensional volume blocks. METHODS: This was a prospective, cross-sectional, observational study including 80 fetuses, whose mothers attended Kepler University Hospital Linz or the Ambulatorium für Fetalmedizin Feldkirch for first-trimester sonography...

The patient had a previous history of laparoscopic myomectomy. At 10 weeks of gestation, she visited our emergency center due to sudden abdominal pain. An ultrasound examination and MRI showed complete rupture of the uterine myometrium in the fundal wall and a floating gestation sac in Douglas' fossa with fluid. Emergency abdominal laparotomy was immediately performed due to the diagnosis of uterine rupture. During surgery, a small defect of the myometrium was found in the posterior fundal wall of the uterus...

The diagnosis of an abnormal fetal posterior fossa is usually done during the second trimester scan. However, some forms of open spina bifida with Arnold-Chiari malformation can be detected from the first trimester ultrasound with a precise examination of the posterior fossa and intracranial translucency. Furthermore, other abnormalities of the posterior fossa such as cystic malformations also seem to be accessible to early detection. This work detailed the possible usual and unusual aspects of the posterior fossa individualized during the first trimester ultrasound scan...

OBJECTIVE: To conduct a literature review to assess the effectiveness of first trimester ultrasonographic markers of spina bifida (SB) integrating data with our prospective experience. METHODS: The analysis of the SB cases that we prospectively detected in the first trimester, between January 2012 and February 2014, and a systematic review of all the papers evaluating the effectiveness of SB ultrasonographic markers at 11-14 weeks, namely brain stem diameter (BS), fourth ventricle/intracranial translucency (IT), cisterna magna (CM), brain stem/occipital bone distance (BSOB), the ratio between BS and BSOB...

OBJECTIVE: To describe the sonographic appearance of fetal posterior fossa anatomy at 11-14 weeks of pregnancy and to assess the outcome of fetuses with increased intracranial translucency (IT) and/or brainstem-to-occipital bone (BSOB) diameter. METHODS: Reference ranges for brainstem (BS), IT and cisterna magna (CM) measurements, BSOB diameter and the BS : BSOB ratio were obtained from the first-trimester ultrasound examination of 233 fetuses with normal postnatal outcome (control group)...

OBJECTIVE: The posterior fossa of normal fetuses was evaluated and compared with those having chromosomal abnormalities at 11-13+6 weeks' gestation in Chinese population. METHODS: In 518 normal fetuses referred to first trimester screening, fetal brain stem (BS) and brain stem to occipital bone distance (BSOB) were measured prospectively. The BS and BSOB were also measured on stored images in fetuses with confirmed trisomy 21 (n = 38), Trisomy 18 (n = 26), Trisomy 13 (n = 8), and monosomy X (n = 8)...