Basic sonographic examination of the fetal brain at 11-13 weeks' gestation: Rationale for a simple and reliable four-step technique.

The widespread incorporation of first-trimester scanning between 11 and 13 weeks' gestation has shifted from the screening of chromosomal abnormalities, mainly by measuring nuchal translucency thickness and visualization of the nasal bone, to a more detailed study of the fetal anatomy leading to early detection of several structural congenital anomalies. This goal can be improved by the routine and focused sonographic assessment of specific anatomic planes and the identification of distinctive landmarks that can help disclosing a particular, non-evident condition. In this article we present the basis for a basic, early examination of the fetal brain during screening using a four-step technique, which can be readily incorporated during the first-trimester scan. The technique includes the focused visualization of the cranial contour, choroid plexuses of the lateral ventricles and midline, aqueduct of Sylvius, brainstem, fourth ventricle, and the choroid plexus of the fourth ventricle. The rationale for this approach is presented and discussed.

The Rule of 10: a simple 3D ultrasonographic method for the diagnosis of T-shaped uterus.

PURPOSE: To investigate and propose a new simple tridimensional (3D) ultrasonographic method to diagnose a T-shaped uterus (Class U1a). METHODS: A multicenter non-experimental case-control diagnostic accuracy study was conducted between January 2018 and December 2019, including 50 women (cases) diagnosed with T-shaped uterus (U1a class) and 50 women with a "normal uterus" (controls). All the enrolled women underwent 3D ultrasound, drawing four lines and recording the length of three of them as follow: draw and measure the interostial line (R0); draw from the midpoint of R0 a perpendicular line length 20 mm; draw and measure in the uterine cavity a line parallel to R0 at 10 mm below R0 (R10) and a second line parallel to R0 at 20 mm below R0 (R20). The diagnostic performance of all sonographic parameters statistically significantly different between T-shaped and normal uteri was estimated using the receiver operator characteristic (ROC) curve analysis. RESULTS: R10 and R20 were statistically significantly shorter in the T-shaped than the normal uterus. R10 reported the highest diagnostic accuracy with an area under the ROC curve of 0.973 (95% CI 0.940-1.000). R10 length maximizing the Youden's J statistic was 10.5 mm. Assuming R10 length equal to or shorter than 10 mm as the cut off value for defining a woman as having a T-shaped uterus, the new ultrasonographic method following the proposed protocol (R0, R10, and R20) reported sensitivity for T-shaped uterus of 91.1% (95% CI 0.78-0.97%) and a specificity of 100% (95% CI 0.89-100%). The positive likelihood ratio was higher than 30, and the negative likelihood ratio was 0.09 (95% CI 0.04-0.26). CONCLUSIONS: Measuring the length of the intracavitary line parallel to the interostial line at 10 mm from it and using a length ≤ of 10 mm as cut off value (the "Rule of 10") appears a simple and accurate 3D ultrasonographic method for the diagnosis of a T-shaped uterus.

First-trimester sonographic diagnosis of sirenomelia: A multicenter series of 12 cases and review of the literature.

OBJECTIVE: To determine the key sonographic features for the diagnosis of sirenomelia in the first trimester of pregnancy. METHODS: Cases of sirenomelia from several prenatal diagnosis centers were retrospectively identified and reviewed. The diagnosis was established through the detection of fused lower limbs. Additional sonographic findings were also noted. RESULTS: A total of 12 cases were collected. The most striking sonographic finding was the detection of malformed lower limbs, which appeared to be fused and in an atypical position. Nuchal translucency thickness was mildly increased in three cases (25%). An abdominal cyst, representing the dilated blind-ending bowel, was noted in seven cases (58%). Color flow imaging detected a single umbilical artery in six cases (50%) and the associated intra-abdominal vascular anomalies in three cases (25%). No cases of aneuploidy were detected. The pregnancy was terminated in nine cases (75%) and intrauterine demise occurred in the remaining three cases (25%). CONCLUSIONS: The sonographic detection of abnormal lower limbs or an intra-abdominal cyst located laterally during the first-trimester scan may be warning signs of sirenomelia. This should prompt a detailed examination of the fetal lower body and intra-abdominal anatomy, including the main abdominal vessels, in order to look for additional confirmatory findings.

Biparietal diameter-to-crown-rump length disproportion in first-trimester fetuses with holoprosencephaly.

OBJECTIVES: To determine whether the biparietal diameter measurement is altered in first-trimester fetuses with holoprosencephaly. METHODS: Cases of holoprosencephaly were collected retrospectively from 4 fetal medicine centers, and first-trimester biparietal diameter measurements were reviewed. The diagnosis of holoprosencephaly was established sonographically by the detection of abnormal choroid plexus morphologic characteristics (absent "butterfly" sign) and the identification of a monoventricular cerebral cavity on axial views of the fetal brain. The proportion of fetuses with biparietal diameter measurements below the 5th percentile for crown-rump length was determined. RESULTS: Among 45 cases of holoprosencephaly reviewed, 43 had information on both biparietal diameter and crown-rump length measurements. The biparietal diameter was below the 5th percentile for crown-rump length in 14 (32.6%) fetuses. Chromosomal analysis was available in 41; no statistically significant difference in biparietal diameter measurement between those with associated chromosomal anomalies and those without anomalies was noted. A supplementary analysis using head circumference measurement showed an even greater proportion of fetuses with holoprosencephaly with measurements below the 5th percentile for crown-rump length (18 of 42 [42.9%]). CONCLUSIONS: One-third of first-trimester fetuses with a sonographic diagnosis of holoprosencephaly had a biparietal diameter that was smaller than expected for crown-rump length. In this subset of fetuses, the evaluation of intracranial anatomy for signs of holoprosencephaly may be more difficult to perform due to the smaller size of the brain. Therefore, the detection of a biparietal diameter below the 5th percentile as expected from crown-rump length on the first-trimester scan may be a warning sign of holoprosencephaly and should prompt a detailed examination of the intracranial anatomy.

Factors Associated with a Post-Procedure Spontaneous Pregnancy after a Hysterosapingo-Foam-Sonography (HyFoSy): Results from a Multicenter Observational Study.

BACKGROUND: Tubal patency testing constitutes an essential part of infertility work-up. Hysterosalpingo-foam-sonography (HyFoSy) is currently one of the best tests for assessing tubal patency. The objective of our study was to evaluate the post-procedure rate of spontaneous pregnancy among infertile women submitted for an HyFoSy exam with ExEm® foam and the factors associated with this. METHODS: Multicenter, prospective, observational study performed at six Spanish centers for gynecologic sonography and human reproduction. From December 2015 to June 2021, 799 infertile women underwent HyFoSy registration consecutively. The patients' information was collected from their medical records. Multivariable regression analyses were performed, controlling for age, etiology, and time of sterility. The main outcome was to measure post-procedure spontaneous pregnancy rates and the factors associated with the achievement of pregnancy. RESULTS: 201 (26.5%) women got spontaneous conception (SC group), whereas 557 (73.5%) women did not get pregnant (non-spontaneous conception group, NSC). The median time for reaching SC after HyFoSy was 4 months (CI 95% 3.1-4.9), 18.9% of them occurring the same month of the procedure. Couples with less than 18 months of infertility were 93% more likely to get pregnant after HyFoSy (OR 1.93, 95% CI 1.34-2.81; p < 0.001); SC were two times more frequent in women under 35 years with unexplained infertility (OR 2.22, 95% CI 1.07-4.65; P0.033). CONCLUSION: After HyFoSy, one in four patients got pregnant within the next twelve months. Couples with shorter infertility time, unexplained infertility, and women under 35 years are more likely to achieve SC after HyFoSy.

MR imaging of thoracic abnormalities in the fetus.

In recent years, with the development of ultrafast sequences, magnetic resonance (MR) imaging has been established as a valuable diagnostic modality complementary to ultrasonography (US). MR imaging offers several technical advantages over US, including a larger field of view, fewer limitations due to maternal habitus, and the ability to visualize fetal anatomy regardless of fetal presentation. The authors discuss the most frequently found thoracic abnormalities, including congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, bronchopulmonary sequestration, bronchogenic cyst, congenital high airway obstruction syndrome, and bronchial obstruction by a mucus plug, specifically with respect to the effect of fetal MR imaging on diagnosis and treatment. MR imaging can assist in establishing the prognosis and in perinatal management, especially in the case of congenital diaphragmatic hernia, which is the most common indication for thoracic MR imaging. MR imaging can demonstrate hernial contents and quantify lung volume better than US, allowing the prognosis to be determined and postpartum extracorporeal membrane oxygenation needs to be estimated. MR imaging can also be used to distinguish different types of cystic adenomatoid malformations, identify the anomalous vessels of pulmonary sequestration, and assess the functional effects of bronchogenic cysts. Balanced sequences (steady-state free precession sequences) allow performance of unenhanced thoracic vascular studies, which are useful in the diagnosis of intralobar or extralobar sequestration. In summary, fetal MR imaging can provide additional data useful in establishing prognosis and in perinatal management of thoracic malformations.

Intracranial translucency at 11-13 weeks of gestation: prospective evaluation and reproducibility of measurements.

OBJECTIVE: This paper aimed to determine the feasibility of identification and measurement reproducibility of intracranial translucency (IT) in our population. METHODS: This is a prospective study in which five accredited operators attempted to identify and measure the IT during first-trimester sonographic screening for aneuploidy in 990 fetuses. The presence or absence of spina bifida was determined at the time of the second-trimester scan or after birth. Measurement reproducibility was assessed through intraclass correlation coefficient (ICC) on a subgroup of 150 fetuses. RESULTS: Identification and measurement of the IT were possible in 961 (97%) cases. The mean IT anteroposterior diameter was 1.8 mm (SD ± 0.37; range 0.8-3.1), and the size increased linearly with advancing gestation (IT = 0.74 + 0.02 × crown-rump length; r(2) = 0.15, p < 0.0001). The only fetus with spina bifida in this series presented with absent IT. Intra-observer and inter-observer ICCs were 0.79 and 0.75, respectively (95% confidence intervals 0.72-0.84 and 0.67-0.81, respectively; both p < 0.001). CONCLUSIONS: The IT increases linearly with increasing crown-rump length and seems to be of value in the first-trimester detection of spina bifida. It is easy to identify and measure and shows excellent intra-observer and inter-observer reproducibility measurements.

First-trimester assessment of the fetal palate: a novel application of the Volume NT algorithm.

We describe a new technique that can facilitate the first-trimester examination of the fetal palate using the Volume NT algorithm (Samsung Medison, Seoul, Korea), a program that automatically detects the exact midsagittal plane of the head and is primarily designed for semiautomatic measurement of the nuchal translucency thickness. Three-dimensional (3D) data sets from the fetal face were captured with Volume NT and subsequently reformatted with the Oblique View software to obtain orthogonal views of the primary and secondary palate in coronal and axial planes, respectively. By testing this method in selected 3D data sets obtained retrospectively (n = 12) and prospectively (n = 28), we were able to extract clinically acceptable views of the fetal palate in all cases. This preliminary report shows that with this new 3D automation development, early evaluation of the fetal palate is feasible and reproducible and could be easily incorporated into the first-trimester sonographic protocol once its ability to detect abnormal cases is demonstrated.

Feasibility of 3-dimensional sonographic examination of the fetal secondary palate during the second-trimester anatomy scan.

OBJECTIVES: To determine the feasibility of obtaining adequate 3-dimensional (3D) data sets to examine the fetal secondary palate during the second-trimester anatomy scan. METHODS: During a 3-month period, 3D data sets of the fetal secondary palate were obtained from consecutive women undergoing routine second-trimester scans. Only structurally normal singleton fetuses with a normal upper lip on 2-dimensional (2D) sonography were included. Three-dimensional data sets were obtained using a mechanical transducer with a 45° sweep and the same settings as for the standard 2D scan, ideally when the fetus was facing the transducer, with mild extension of the head, and the ultrasound beams projecting caudally to cranially to avoid shadowing from the primary palate or mandible. No additional scanning time was allocated for examination of the palate. Acquired 3D data sets were analyzed offline using dedicated software, and the secondary palate was assessed using the "flipped face" technique. RESULTS: Ninety-seven women met entry criteria and underwent second-trimester scans at a median gestational age of 22 completed weeks (range, 18-23 weeks). In 13 (13.4%) cases, it was not possible to obtain a midsagittal view of the face for capturing 3D volume data sets due to fetal position. Additional factors limiting visualization were shadowing from the primary palate in fetuses with flexion of the head in 30 (30.9%) cases, interposition of, or shadowing from, fetal arms or legs in 11 (11.3%), inability to reproduce a true midsagittal plane in 8 (8.2%), and poor image quality in 1 (1%). Therefore, it was only possible to assess the secondary palate in 34 (35.1%) cases. CONCLUSIONS: It is not feasible to obtain adequate 3D data sets for offline analysis of the fetal secondary palate in almost two-thirds of second-trimester fetuses during the routine scan. However, suboptimal visualization is primarily due to factors related to fetal position rather than equipment or image quality. This finding suggests that a dedicated scan, during which adequate time can be devoted to obtaining a satisfactory position in which the fetal face can be evaluated, may be warranted in high-risk cases.

Antenatally diagnosed renal duplex anomalies: sonographic features and long-term postnatal outcome.

OBJECTIVES: The purpose of this study was to assess the diagnostic accuracy and infant outcomes of antenatally detected renal duplex anomalies. METHODS: An observational longitudinal study of cases of renal duplex anomalies diagnosed on prenatal sonography was conducted. Information on the prenatal sonographic findings, antenatal course, and perinatal outcome was obtained by reviewing the sonography reports and delivery records. Postnatal follow-up, including neonatal and infant evaluations, was obtained from hospital records. RESULTS: During a 7-year period, a total of 24 cases of renal duplex anomalies were identified prenatally. Three cases were excluded from subsequent analysis because of termination of pregnancy after the diagnosis of a severe brain abnormality, loss to follow-up, and an inability to confirm the prenatal diagnosis on neonatal renal sonography. Among the 21 confirmed cases, the presence of two separate renal pelvises was the most common prenatal sonographic feature (n = 15 [71%]), followed by dilatation of a single moiety with a dilated ipsilateral ureter or ureterocele (n = 6 [29%]). In 43% of cases, the renal duplex anomalies had no adverse associations, but in 48%, they were complicated by a urinary tract infection, and 48% of the infants required a surgical procedure during early childhood. CONCLUSIONS: Renal duplex anomalies can be accurately diagnosed by prenatal sonography even when there is minimal dilatation of the renal pelvis. Antenatal diagnosis allows planning of postnatal care, which may prevent urinary tract infections and renal function impairment. The natural history of antenatally diagnosed duplex anomalies seems to be overall benign, with urinary tract infections and the need for surgery being the most common complications in affected infants.

First-trimester assessment of the nasal bones using the retronasal triangle view: a 3-dimensional sonographic study.

OBJECTIVE: The purpose of this study was to evaluate a new sonographic technique for identifying the nasal bones using the retronasal triangle view, ie, the coronal plane at which the palate and frontal processes of the maxilla are simultaneously visualized. METHODS: Three-dimensional (3D) volumes were acquired from women undergoing first-trimester sonographic screening for aneuploidy by 2 accredited operators. Those data sets in which the fetal face was clearly identified were selected for offline analysis by 2 other observers who were unaware of the sonographic or clinical findings. The nasal bones were classified as both present, only 1 present (right or left), or absent according to the presence or absence of 2 small paired echogenic linear structures at the upper tip of the retronasal triangle as determined by 3D navigation in the coronal plane and compared to those findings obtained by 3D navigation in the sagittal plane. Additional 3D data sets involving a subset of 4 first-trimester fetuses with trisomy 21 and absent nasal bones were also analyzed retrospectively and included randomly in the study group. RESULTS: A total of 110 3D data sets were analyzed, of which 86% were obtained transabdominally and 14% transvaginally. The quality of nasal bone identification was classified subjectively by the observers as good in 67% of cases, fair in 29%, and poor in 4%. The nasal bones were classified as at least 1 present in 106 of the cases (96%) and absent in 4 (4%), with complete agreement between observers in both the sagittal and coronal planes (κ = 1). Discrimination between the right and left nasal bones was possible in 89% and 93% for observer A and in 96% and 96% for observer B by assessing the sagittal and coronal views, respectively (right nasal bone: κ = 0.90 [95% confidence interval (CI), 0.79-1]; left nasal bone: κ = 0.85 [95% CI, 0.60-0.99]). The nasal bones were not identified at the level of the retronasal triangle view in any of the fetuses with trisomy 21 and absent nasal bones. CONCLUSIONS: This study shows that the nasal bones can be confidently identified as paired echogenic structures located at the upper tip of the retronasal triangle. This coronal view of the fetal face offers the possibility of screening for the presence or absence of the nasal bones in the first trimester, especially when the standard midsagittal views of the fetal face are suboptimal because of fetal or maternal factors. Because both nasal bones can be evaluated simultaneously in the coronal plane, the retronasal triangle view may be advantageous over the conventional midsagittal view assessment, in which only 1 of the 2 nasal bones is evaluated.

Real-Life Diagnostic Accuracy of MRI in Prenatal Diagnosis.

There is some controversy about the value of fetal MRI in prenatal diagnosis, and most of the studies examine its accuracy in central nervous system (CNS) pathology. The objective of this retrospective study was to assess the diagnostic accuracy and usefulness of fetal MRI in the prenatal diagnosis of central nervous system (CNS) pathology and non-CNS pathology. Patients referred to the Radiology Department between 2007 and 2018 for a fetal MRI after detection of an anomaly in the fetal ultrasound, a high-risk pregnancy, or an inconclusive fetal ultrasound (n = 623) were included in the study. Postnatal diagnosis was used to assess the diagnostic accuracy of MRI. Fetal MRI was considered to provide additional information over fetal ultrasound when findings of the fetal MRI were not detected in the fetal ultrasound or when established a pathological condition that was not detected in the fetal ultrasound. Fetal MRI provided useful information for the perinatal management and prognosis over fetal ultrasound when findings of the fetal MRI changed the postnatal prognosis, leaded to the decision to legally terminate the pregnancy, changed prenatal or postnatal follow-up, or helped in the planning of prenatal or postnatal treatment. Fetal MRI offered an accurate diagnosis in 97% of cases (compared to 90.4% of fetal ultrasound; p < 0.001). Concordance between fetal ultrasound and fetal MRI was 92.1%. Fetal MRI provided additional information over fetal ultrasound in 23.1% of cases. In 11.6% of cases, the information was useful for the perinatal management and prognosis. In 45 cases (7.2%), fetal MRI was the only accurate diagnosis. In conclusion, fetal MRI has a superior diagnostic accuracy, especially in CNS pathology, and provides additional useful information in CNS, thoracic, and abdominal pathology.

Fetal intracranial hemorrhage. Prenatal diagnosis and postnatal outcomes.

OBJECTIVE: To present our experience with 14 cases of fetal intracranial hemorrhage (ICH). METHODS: Cases of fetal ICH detected in our institution between 2005 and 2016 by ultrasonography. Maternal characteristics, ultrasound and MRI findings, and postnatal outcome were noted. RESULTS: Twelve cases (86.7%) were identified during a third trimester routine scan at a median gestational age of 30.6 weeks. The ICH was classified as Grade 2 in two cases, Grade 3 in three cases, and Grade 4 in nine cases. Nine cases were bilateral and five were unilateral (four left/one right). The 11 MRI available confirmed grade and location and, in six cases (54.5%), added new findings. There were six terminations of pregnancy, one intrauterine fetal death and seven babies born alive. These were followed up for 28 months (range 3-96). Some grade of neurologic impairment was observed in five children (71.4%, one Grade 3/four Grade 4), mainly mild to moderate motor sequelae. CONCLUSION: Diagnosis of fetal ICH is amenable to antenatal US. Most of the cases identified are of high grade and usually detected during the third trimester. MRI is a valuable complementary tool in evaluating ICH. Conversely to that previously reported, postnatal survival is high but it entails the risk of adverse neurologic outcome in most neonates.

Brainstem-vermis and brainstem-tentorium angles: 3D ultrasound study of the intra- and inter-observer agreement.

OBJECTIVE: The brainstem-vermis angle (BVA) and the brainstem-tentorium angle (BTA) have been proposed to quantify vermian and tentorial alterations associated to fetal posterior fossa malformations. Our objective is to evaluate the intra- and inter-observer agreement for the measurement of these angles during the prenatal ultrasound scan. METHODS: Fifteen 3 D sets from fetuses with posterior fossa pathology were processed by multiplanar navigation. Four experts in prenatal ultrasound measured the BVA and the BTA on a mid-sagittal view of the fetal brain, following the criteria described by Volpe. Observer 1 did also repeated measurements following both the criteria by Volpe and Ghi. The intraclass correlation coefficient (ICC) was used to test consistency and absolute agreement for intra- and inter-observer measurements. The concordance is poor when ICC <0.40 and excellent when ICC >0.75. RESULTS: Consistency ICC for measurements between the 4 observers was 0.74 (95% CI: 0.54-0.89) for the BVA and 0.55 (95% CI: 0.29-0.78) for the BTA. Absolute agreement ICC was 0.67 (BVA) and 0.45 (BTA). The intra-observer study showed a significantly greater angle with the criteria by Ghi (mean 52.1°, 95% CI: 49.5-54.8) than with the criteria by Volpe (mean 37.4°, 95% CI: 33.1-41.6). CONCLUSIONS: A more precise methodology for the measurement of these angles should be described.

Eminencia ganglionar: Anatomía y patología en resonancia magnética fetal / Ganglionic Eminence: Anatomy and Pathology in Fetal MRI

Se presentan dos casos de resonancia magnética (RM) fetal en los que se detectan anomalías de las eminencias ganglionares (EG): un caso en una gestación única y otro en una gestación gemelar con solo uno de los fetos afectado. Las alteraciones en las eminencias ganglionares son entidades poco frecuentes, con muy pocos casos publicados, tanto por RM como por ecografía fetal, que suelen asociarse con alteraciones neurológicas graves. Se describen los hallazgos por RM de la patología de las EG en estos dos casos, no visibles en la ecografía previa.

We present two cases of fetal MRI where anomalies of the ganglionic eminences (GE) are detected, one case in a single pregnancy and another in a twin gestation with only one of the affected fetuses. Alterations in the ganglionic eminences are rare entities, with very few published cases, both by MRI and fetal ultrasound, which are usually associated with severe neurological alterations. The MR findings of the pathology of the GE in these two cases are described. These findings were not visible on the previous ultrasound.

Resonancia magnética en el diagnóstico del teratoma intracraneal fetal / MRI in the Diagnosis of Fetal Intracranial Teratoma

Los tumores intracraneales fetales son poco comunes, pero cuando aparecen están asociados con una elevada mortalidad. Muchos de los tumores cerebrales congénitos a menudo provocan la muerte fetal intrauterina, lo que limita la evaluación precisa de su prevalencia e incidencia del tumor. El más frecuente es el teratoma, que se caracteriza por estar constituido por células dependientes de las tres capas germinales. Estos tumores suelen detectarse en las ecografías habituales de control prenatal y, frecuentemente, son tan grandes que se dificulta determinar su origen. Por ello, ante la sospecha ecográfica, se recomienda completar el estudio con una RM fetal. Se presenta un caso de una gestante de 20 semanas, en quien se detecta un tumor intracraneal fetal en una ecografía de control prenatal. Se decide completar el estudio con una RM fetal en la que se visualiza una masa dependiente de la glándula pineal con extensión anterior, compatible con teratoma. Se decidió la interrupción voluntaria del embarazo, y en el estudio histológico tras la necropsia se confirmó un teratoma inmaduro. La RM es la prueba de imagen de elección tras la sospecha diagnóstica ecográfica. Por su alta resolución aporta información relevante que permite valorar mejor la arquitectura interna del tumor, así como su origen y extensión. Además, sirve para evaluar el resto de estructuras intracraneales.

Fetal intracranial tumors are rare but, when they do occur they are associated with high fetal mortality. Many of the congenital brain tumors often result in intrauterine fetal death, limiting accurate assessment of tumor prevalence and incidence. The most frequent is teratoma, which is characterized by cells dependent on the three germ layers. These tumors are usually detected in the usual prenatal control ultrasounds, and are often so large that it is difficult to determine their origin. When ultrasound suspicion exists, a fetal MRI study is recommended. The case of a 20- week pregnant woman is presented, in which a fetal intracranial tumor was detected on a prenatal control ultrasound. It was decided to complete the study with a fetal MRI in which a pineal gland mass with anterior extension, compatible with teratoma, was visualized. Voluntary termination of pregnancy was decided, and the histological study after necropsy confirmed that it was an immature teratoma. MRI is the imaging test of choice after suspected diagnostic ultrasound, as its high resolution provides relevant information that allows better assessment of the internal architecture of the tumor, as well as its origin and extension. In addition, it also serves to evaluate the rest of the intracranial structures.

Fetal magnetic resonance imaging and three-dimensional ultrasound in clinical practice: applications in prenatal diagnosis.

Three-dimensional ultrasound and magnetic resonance imaging are powerful imaging techniques that are used increasingly in evaluating fetal anatomy. In this chapter, we review the main applications of these imaging modalities in current practice and present an overview of the malformations that may benefit from assessment with three-dimensional ultrasound and magnetic resonance imaging.

Fetal magnetic resonance imaging and three-dimensional ultrasound in clinical practice: general aspects.

Ultrasonography is used routinely during pregnancy to screen and diagnose fetal anomalies. Two-dimensional ultrasound is usually adequate in women at low risk for malformations. When technical factors limit optimal evaluation or a malformation is suspected, further imaging with three-dimensional ultrasound and magnetic resonance imaging is becoming increasingly common. Three-dimensional ultrasound allows the manipulation of data acquired from two-dimensional ultrasound to recreate an infinite number of views, thereby enhancing the ability to evaluate the fetal anatomy. When three-dimensional ultrasound is either unavailable or inadequate, fetal magnetic resonance imaging permits detailed evaluation of the suspected anomaly and assesses the presence of associated anomalies. In this chapter, we review the techniques, advantages, limitations, and clinical applications of these two fetal imaging modalities.

RM fetal: patología torácica y abdómino-pélvica / Fetal MRI: thoracic, abdominal and pelvic pathology

Aunque la ecografía (US) es el método de elección en la evaluación del feto, la resonancia magnética (RM) es una técnica complementaria a la US en el diagnóstico de las anomalías fetales. Entre las ventajas de la RM se destacan un excelente contraste tisular, un campo de visión grande y una relativa operador-independencia. La mayoría de los trabajos previos de RM fetal han estudiado el sistema nerviodo central (SNC). Sin embargo, la RM es útil en la evaluación de las anomalías torácicas y abdominales. En este artículo se muestran los diferentes aspectos por RM de las anomalías fetales torácicas y abdominales y se discuten las indicaciones y ventajas de la RM fetal...

RM fetal en las anomalías del SNC: Aspectos de interés para el obstetra / Abnormalities in fetal CNS: Interesting issues to the obstetrician

La resonancia magnética (RM) fetal es una técnica de imagen en auge, útil en la valoración del cerebro y columna fetal. Ayuda a estudiar el desarrollo cerebral fetal y se puede realizar un diagnóstico precoz de las anomalías congénitas. La imagen de RM muestra gran resolución de contraste y permite diferenciar mejor que la ecografía entre hallazgos normales y patológicos. Además, algunas malformaciones cerebrales o lesiones destructivas ocultas en la ecografía prenatal pueden ser detectadas por RM. Revisamos las indicaciones, utilidad, seguridad, aspectos técnicos de la RM fetal y la apariencia del desarrollo cerebral fetal, y evaluamos su contribución en el diagnóstico de las patologías de las diferentes regiones cerebrales y de la patología espinal fetal.

Fetal MR imaging (MRI) is an increasingly available technique used to evaluate the fetal brain and spine, because it provides a unique opportunity to evaluate fetal brain development and to make an early diagnosis of congenital abnormalities. MRI allows a better differentiation between normal and abnormal signal intensity of fetal tissues due to its higher contrast resolution compared to prenatal sonography (US). Therefore, structural abnormalities such as brain malformations and destructive lesions that could be sonographically occult on prenatal sonography can be detected at fetal MRI. We review indications, utility, safety, and technical aspects of fetal MR imaging and the appearance of normal fetal brain development evaluating its contribution in the diagnosis of fetal diseases of different brain regions and spinal disorders.