Fetal magnetic resonance imaging enhances detection of spinal cord anomalies in patients with sonographically detected bony anomalies of the spine.

OBJECTIVE: Although fetal magnetic resonance imaging (MRI) is being increasingly used to evaluate sonographically suspected abnormalities, its utility in the evaluation of the spinal canal is not well studied. Because it is not susceptible to the limitations of fetal position, oligohydramnios, and shadowing from bony structures, we hypothesize that fetal MRI is better suited to assess the contents of the spinal canal compared with prenatal sonography. The purpose of this investigation was to determine whether fetal MRI could detect spinal abnormalities in cases in which they had not been originally suspected on prenatal sonography. METHODS: Fetal spine MR images were retrospectively reviewed over a 42-month period. Corresponding sonographic images were then rereviewed to determine whether there were findings in retrospect that might have suggested the cord abnormalities. Cases of myelomeningocele were counted as a spinal cord abnormality only if fetal MRI showed a cord anomaly other than the myelomeningocele. RESULTS: Of 33 cases referred for bony anomalies of the spine, fetal MRI showed additional abnormalities involving the spinal cord in 3 patients. These included diastematomyelia in 2 cases and segmental spinal dysgenesis in the third case. One case of diastematomyelia occurred in association with a lumbosacral myelomeningocele. The spinal cord anomalies were not visible on any of the prenatal sonograms, even in retrospect. CONCLUSIONS: Additional spinal cord anomalies were detected in 10% of cases reviewed. Fetal MRI can be useful in assessing the spinal cord in fetuses with bony spinal anomalies. Our findings suggest that fetuses with sonographically diagnosed bony abnormalities of the spine may benefit from further evaluation with fetal MRI.     

胎儿胼胝体发育不良的超声和磁共振对比观察

目的 探讨超声与MRI在胎儿胼胝体发育不良(ACC)产前诊断中的应用价值。方法 超声怀疑胎儿ACC孕妇16名,均在超声检查后3天内接受胎儿MR检查。将超声、MRI结果与出生后或引产后结果对照。结果 16名孕妇共检出胎儿16胎,MRI证实14胎为胎儿ACC(出生后随访证实5胎,引产后证实9胎),1胎为单纯双侧脑室扩张伴灰质易位,1胎为脑白质、脑干发育不良。MRI与超声比较,诊断胎儿ACC一致者7胎;超声可疑、MRI肯定者7胎;对于其伴发中枢神经系统畸形,两者一致者7胎,MRI多于超声者4胎。结论 超声检查是产前筛查胎儿ACC的普遍方法;MRI对胎儿ACC的显示明显优于超声,有助于明确诊断胎儿ACC并判断其分型及合并畸形。     

Asymmetric Ventriculomegaly,Interhemispheric Cyst,and Dysgenesis of the Corpus Callosum (AVID)

A series of 20 cases from 2 academic institutions is presented with a characteristic imaging triad of asymmetric ventriculomegaly, a large interhemispheric cyst, and partial or complete agenesis of the corpus callosum. Most cases were initially referred as aqueduct stenosis and hydrocephalus or focal porencephaly. We describe the imaging findings that identify an abnormal or absent corpus callosum associated with a type 1 interhemispheric cyst in fetuses initially thought to have hydrocephalus attributable to aqueductal stenosis. We suggest that the acronym AVID (asymmetric ventriculomegaly, interhemispheric cyst, and dysgenesis of the corpus callosum) may be useful in recognition of these cases. All cases presented with markedly asymmetric ventriculomegaly on initial sonography, with progressive hydrocephalus throughout gestation. Fetal magnetic resonance imaging was performed in 15 of 20 cases. Thirteen of 20 cases were identified in male fetuses. Associated fetal and postnatal abnormalities are also reported. Technological improvements in sonography and fetal magnetic resonance imaging allow improved characterization of associated intracranial anomalies in the setting of hydrocephalus. Accurate diagnosis can aid parental counseling, especially because isolated aqueductal stenosis suggests a better prognosis than hydrocephalus with anomalies. Markedly asymmetric ventriculomegaly in this series was the key to excluding isolated aqueductal stenosis and was associated with callosal malformation with a type 1a interhemispheric cyst.     

Characteristics, associations and outcome of partial agenesis of the corpus callosum in the fetus.

OBJECTIVES: To report, in a population of fetuses diagnosed with partial agenesis of the corpus callosum (PACC), the sonographic characterization, incidence of cerebral, extracerebral and chromosomal anomalies, and outcome. In addition, in some of our cases a comparison was made between findings on ultrasound and fetal magnetic resonance imaging (MRI). METHODS: This was a retrospective study of all cases of PACC seen at two referral centers for prenatal diagnosis of congenital anomalies over a 10-year period. The following variables were assessed: indication for referral, additional cerebral and extracerebral malformations, chromosomal abnormalities, and pregnancy and fetal/neonatal outcome. RESULTS: Among 54 cases of fetal agenesis of the corpus callosum detected in the referral centers during the observation period, PACC was diagnosed at prenatal sonography in 20 cases and confirmed at pre/postnatal MRI and necropsy examinations in 19 cases (35%). These 19 constituted the study group. The diagnosis was made in the sagittal planes and in 12 cases it was made prior to 24 weeks. In most cases the indication for referral was the presence of indirect signs of callosal anomalies, such as colpocephaly. In 10 cases PACC occurred in association with other anomalies and in nine it was isolated. MRI was particularly useful for demonstrating some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. Regarding pregnancy outcome, of those diagnosed before 24 weeks which had associated anomalies, all except two were terminated. Of the nine cases with isolated PACC, all were liveborn. Follow-up was available in eight, and two of these (25%) showed evidence of significant developmental delay. In our series the outcome of isolated PACC was not better than that of complete agenesis of the corpus callosum reported in other series. CONCLUSIONS: PACC can be diagnosed reliably and characterized in prenatal life. The sonographic sign present in most cases is colpocephaly. Prenatal MRI can be performed to confirm the diagnosis. It is particularly useful to demonstrate some additional cerebral anomalies such as late sulcation, migrational pathological conditions and heterotopia. The relatively poor survival rate is due to the high rate of terminations and associated major anomalies.     

Fetal brain imaging: a comparison between magnetic resonance imaging and dedicated neurosonography.

OBJECTIVES: To evaluate whether fetal brain magnetic resonance imaging (MRI) adds useful clinical information to that obtained by dedicated fetal neurosonography using a combined transabdominal and transvaginal approach in fetuses with suspected brain anomalies. METHODS: In the 2-year period between January 2000 and January 2002, 42 fetuses underwent neurosonographic and MRI examinations of the brain. The referral indications were: asymmetric ventriculomegaly (13), ventriculomegaly (7), periventricular cysts (2), suspected midline findings (7), agenesis of the corpus callosum (3), infratentorial pathology (3), cytomegalovirus (CMV) infection (2) and miscellaneous indications (5). RESULTS: Neurosonography and MRI produced similar diagnoses in 29 fetuses: normal examination (10), isolated asymmetric ventriculomegaly (11), isolated ventriculomegaly (3), periventricular cysts (2), agenesis of the corpus callosum (1), pericallosal lipoma (1) and cerebellar hemorrhage (1). The neurosonographic diagnoses were more accurate in seven patients: hemimegalencephaly, pericallosal lipoma, signs of CMV infection, brain anomalies associated with agenesis of the corpus callosum and three fetuses with a normal ultrasound scan in which MRI suggested a parenchymal abnormality. MRI provided a more accurate diagnosis in three patients: a third ventricular dilatation was ruled out, normal ventricles in a fetus with an ultrasonographic finding of asymmetric ventricles, and diagnosis of progression of asymmetric ventriculomegaly. In three patients the identified pathologies were differently interpreted, each examination provided another aspect of the anomaly or a definitive diagnosis was not possible. CONCLUSIONS: Our study demonstrated that dedicated neurosonography is equal to MRI in the diagnosis of fetal brain anomalies. In most of the cases MRI confirmed the ultrasonographic diagnosis; in a minority of cases each modality provided additional/different information. The major role of MRI was in reassurance of the parents regarding the presence or absence of brain anomalies.     

胎儿胼胝体发育不全的MRI诊断

目的 探讨MRI在胎儿胼胝体发育不全(ACC)诊断中的应用价值.方法 39例孕妇,年龄19～35岁;孕龄22～39周,平均29周.产前常规行超声(US)检查后24～48 h内行MR检查,采用二维快速平衡稳态采集(2D FIESTA)序列、单次激发快速自旋回波(SSFSE)序列、快速反转恢复运动抑制(FIRM)序列及扩散...     

胎儿胼胝体缺如产前超声及磁共振诊断的应用分析

目的分析胎儿胼胝体缺如的产前超声及磁共振诊断价值。 方法对2013年7月至2014年12月湖北省妇幼保健院产前超声筛查怀疑胼胝体缺如的67例胎儿于超声检查后3 d内行颅脑磁共振检查,与引产或出生后检查结果对照,对产前超声及磁共振检查结果进行分析。 结果产前超声怀疑胼胝体缺如的67例胎儿磁共振检查后均证实为胼胝体缺如,其中胼胝体完全缺如58例,胼胝体部分缺如9例（均为胼胝体体部和压部缺如）。胎儿胼胝体缺如在磁共振正中矢状位图像上表现为胼胝体完全或部分缺如,脑回呈放射状排列;在横轴位和冠状位图像上表现为侧脑室轻至中度扩张,形态失常。 结论磁共振对胎儿胼胝体缺如有较高的诊断价值,可作为产前超声的补充和验证方法,在产前超声检查怀疑胎儿胼胝体异常时,应行胎儿磁共振检查明确诊断。超声与磁共振联合筛查,是胎儿中枢神经系统畸形产前检查中重要的影像学诊断方法。     

What Does Magnetic Resonance Imaging Add to the Prenatal Sonographic Diagnosis of Ventriculomegaly?

OBJECTIVE: The purpose of this study was to determine the contribution of magnetic resonance imaging (MRI) in evaluating fetuses with the sonographic diagnosis of ventriculomegaly (VM). METHODS: Over 4 years, consecutive fetuses with the sonographic diagnosis of VM at 1 facility who underwent prenatal MRI at a second facility were included. The roles of MRI and follow-up sonography were tabulated. The patients were analyzed in 2 groups based on the presence or absence of other central nervous system (CNS) abnormalities. RESULTS: Twenty-six fetuses with a gestational age range of 17 to 37 weeks had sonographically detected VM (atria > or =10-29 mm), including 19 with mild VM (atria 10-12 mm). In group 1, 14 had isolated VM, 6 of which reverted to normal by the third trimester. Magnetic resonance imaging showed cerebellar hypoplasia not shown by sonography in 1 fetus and an additional finding of a mega cisterna magna in a second fetus. In group 2, 12 fetuses had VM and other CNS anomalies on sonography. Additional findings were seen with MRI in 10 of these fetuses, including migrational abnormalities (n = 4), porencephaly (n = 4), and 1 diagnosis each of abnormal myelination, hypoplasia of the corpus callosum, microcephaly, a kinked brain stem, cerebellar hypoplasia, and congenital infarction. There were significantly more fetuses with additional CNS anomalies found by MRI among those in group 2 compared with those in group 1 (Fisher exact test, P = .001). CONCLUSIONS: Although sonography is an accurate diagnostic modality for the evaluation of fetuses with VM, MRI adds important additional information, particularly in fetuses in whom additional findings other than an enlarged ventricle are seen sonographically.     

Fetal ear length measurement: a useful predictor of aneuploidy?

OBJECTIVE: To determine the usefulness of short ear length (EL) measurement in the prenatal detection of fetuses with chromosomal abnormalities. DESIGN: Fetal EL measurements, routine biometry and complete anatomic survey for fetal abnormalities were prospectively performed by antenatal sonography. SUBJECTS: One thousand eight hundred and forty-eight patients with singleton pregnancies undergoing genetic amniocentesis in the second or third trimester. METHODS: Complete data for EL, biometry and anatomic survey for major structural abnormalities and minor sonographic markers of chromosomal abnormality were available in 1311 fetuses. Of these, 48 (3.7%) had an abnormal karyotype and 1263 (96.3%) had a normal karyotype. Using an EL measurement of < or = 10th percentile for corresponding gestational age in normal fetuses as abnormal cut-off values, detection rates for chromosomal abnormalities by short EL were determined. RESULTS: Among the 48 abnormal karyotypes, 34 were considered significant, and 11 of these 34 (32.4%) fetuses had short EL. In 14 cases, the karyotypic abnormality was considered non-significant and fetal EL was normal in all cases. Of the 34 fetuses with significant chromosomal abnormalities, six (17.6%) on antenatal sonography had no detectable abnormal findings, other than short EL. An increased biparietal diameter (BPD)/EL ratio of > or = 4.0 was also noted in fetuses with an abnormal karyotype, but the sensitivity and predictive value of increased BPD/EL ratio alone or increased BPD/EL ratio in combination with short EL was no better than the sensitivity and predictive value of short EL alone. A combination of short EL and abnormal ultrasound, however, gave a much higher positive predictive value (46%) for significant chromosomal abnormalities. CONCLUSIONS: Our findings suggest that in women at high risk for fetal chromosomal abnormality, a short fetal EL measurement on prenatal ultrasound, either alone or in combination with other sonographically detectable structural abnormalities, may be a useful parameter in predicting fetal aneuploidy.     

Prenatal diagnosis of herniated Dandy-Walker cysts.

OBJECTIVE: The purpose of this series is to describe the prenatal diagnosis and pregnancy outcome of fetuses affected with Dandy-Walker malformation in which a posterior cyst herniated through a bony defect of the occipital skull, foramen magnum, or both. METHODS: Two- and 3-dimensional sonography were used to examine 2 fetuses with poorly delineated cerebellar structures and a large posterior cystic neck mass. Fetal magnetic resonance imaging (MRI) was added to this evaluation as a complementary diagnostic modality. RESULTS: Three-dimensional sonography helped characterize the precise site of cyst herniation through the occipital skull or foramen magnum. Fetal MRI confirmed the sonographic findings. Neonatal MRI studies identified heterotopic gray matter as evidence of a neuronal migration disorder in both fetuses. The second fetus also had agenesis of the corpus callosum. Retrospective review of the fetal MRI (25.9 weeks' menstrual age) and 3-dimensional sonographic (18.7 weeks' menstrual age) studies confirmed ventricular wall nodularity involving the occipital horns of the second fetus. CONCLUSIONS: The antenatal detection of a large posterior cystic neck mass and a poorly defined or nonvisualized cerebellar vermis suggest Dandy-Walker malformation with a herniated cyst. Three-dimensional sonography and fetal MRI are important adjunctive methods that can be used to evaluate the herniation site and a possible neuronal migrational disorder.     

胎儿透明隔腔异常产前诊断与妊娠结局分析

目的 探讨产前超声及磁共振(MRI)检查在胎儿透明隔腔异常产前诊断中的应用价值,分析不同类型透明隔腔异常胎儿的妊娠结局.方法 对2018年1月至2019年12月在南方医科大学第一临床医学院深圳妇幼保健院产前超声会诊中心检查并诊断为透明隔腔异常34例胎儿的产前颅脑超声、MRI及终止妊娠胎儿标本、围生期新生儿颅脑影像学检查...     

The transfrontal view: a new approach to the visualization of the fetal midline cerebral structures.

The objective of this study was to assess the feasibility of using the frontal suture as an acoustic window to visualize sonographically the midline cerebral structures (transfrontal view) in midtrimester fetuses. The study design was prospective and observational. In 124 healthy fetuses and in 2 fetuses with agenesis of the corpus callosum at 19 to 24 weeks' gestation, an attempt was made to obtain a transfrontal view by using transabdominal sonography. The transfrontal view was successfully and rapidly obtained in 110 (89%) of the healthy fetuses; it always provided detailed visualization of the entire corpus callosum, cavum septi pellucidii, third ventricle, brain stem, fourth ventricle, vermis cerebelli, and cisterna magna. The anatomic information was comparable with that obtained from a median sagittal scan obtained through the anterior fontanelle. In both fetuses with agenesis of the corpus callosum, the transfrontal view provided clear evidence of the anomaly. The transfrontal view is feasible in midtrimester fetuses and allows rapid demonstration of the cerebral midline structures and the corpus callosum in particular. It may be helpful in the diagnosis or exclusion of cerebral anomalies, and at least in some cases, it may obviate the need for a transvaginal examination. The transfrontal view may also be used to standardize the scanning plane for the evaluation of the fetal facial profile.     

MRI评价胎儿胼胝体缺如及其合并畸形

目的 利用MRI评价胎儿胼胝体缺如及其合并畸形。方法 对81胎MRI诊断胼胝体缺如胎儿，分析胼胝体缺如类型，观察其合并颅脑畸形类型及数目。结果 81胎中，单纯胼胝体缺如47胎、合并畸形34胎；合并蛛网膜囊肿12胎，Dandy-Walker畸形7胎，小脑发育不良5胎，神经元移行异常5胎，大枕大池4胎，室管膜下囊肿4胎，脑实质出血2胎，脑裂畸形、脑穿通畸形及脑膜膨出各1胎。结论 MRI可显示胼胝体缺如胎儿及其合并其他颅脑畸形，为评估胎儿预后提供更多信息。     

Magnetic resonance imaging in pregnancy: study of fetal cerebral malformations.

This paper reports 15 examinations by magnetic resonance imaging (MRI) performed in pregnant women whose fetuses had cerebral malformations identified by sonography. In all the cases the fetuses were immobilized by ultrasound-guided intravenous or intramuscular curarization.The diagnoses by MRI and ultrasound differed only in one case where an occipital meningocele had first been suggested. No cerebral abnormalities were demonstrated in this case by the MRI study, and this was confirmed at birth. In the remaining 14 cases, MRI confirmed the ultrasound diagnosis of cerebral malformation. In four of these cases, MRI added some additional information to the ultrasound diagnosis of ventriculomegaly by detecting agenesis of the corpus callosum in two fetuses, one Chiari malformation and one triventricular hydrocephalus. Another two ultrasound diagnoses of microcephaly actually proved to be semilobar holoprosencephaly with MRI. In the following cases, the MRI diagnoses concurred with those of ultrasound, and was therefore used unnecessarily despite providing further anatomical details of the lesions: two cases of agenesis of the corpus callosum, one case of anencephaly, a cystic hygroma of the neck, an alobar holoprosencephaly, a Dandy-Walker malformation and a mild isolated hydrocephalus associated with diaphragmatic hernia. In one case of iniencephaly, sonography offered closer approximation to the correct diagnosis. The results obtained unequivocally confirm the high sensitivity of ultrasound examinations in the prenatal screening of cerebral malformations and show that MRI proves to be complementary in uncertain cases or when more accurate anatomical detail is required.     

Prenatal diagnosis of agenesis of the corpus callosum

The prenatal sonographic findings in seven cases of agenesis of the corpus callosum (AGCC) are reported. Findings that suggest AGCC on standard transverse views of the fetal cranium are emphasized. All seven cases demonstrated ventricular abnormalities including four fetuses (57%) who demonstrated laterally displaced lateral ventricles and/or disproportionate enlargement of the occipital horns. Two additional fetuses demonstrated a large midline fluid collection, representing a dilated third ventricle. The remaining case demonstrated atypical findings of a septated periventricular cystic mass. Following birth, additional malformations were found in 5 of the 7 fetuses (71%), including one fetus with trisomy 8. We conclude that AGCC can be suggested on the basis of prenatal sonographic findings and that awareness of typical findings should permit more frequent detection of this anomaly in utero. Due to the frequency of concurrent anomalies, identification of AGCC should initiate a careful search for additional malformations.     

Prenatal ultrasound findings of lissencephaly associated with Miller-Dieker syndrome and comparison with pre- and postnatal magnetic resonance imaging.

OBJECTIVE: To report on the prenatal ultrasound findings in fetuses with lissencephaly associated with Miller-Dieker syndrome (MDS) and to compare these findings with those of magnetic resonance imaging (MRI). METHODS: Cases of MDS confirmed by postnatal chromosome microdeletion analysis were identified through review of patient records. Prenatal ultrasound scans were reviewed retrospectively by two radiologists. For cerebral cortical development, the Sylvian, parieto-occipital and calcarine fissures, and the cingulate sulcus and sulci over the cerebral convexity were evaluated. If one or more of these fissures or sulci were not visualized at the expected gestational age or their appearance was abnormal for gestational age, cortical development was considered delayed. Prenatal and postnatal MRI examinations were reviewed by a pediatric neuroradiologist. RESULTS: There were seven cases of MDS. In three cases, the prenatal diagnosis of agyria/lissencephaly was prospectively suspected by ultrasound at 23, 26 and 30 weeks, and subsequently confirmed by prenatal MRI. When we retrospectively reviewed the prenatal ultrasound scans of all fetuses, all had delayed cortical development identified on ultrasound performed after 23 weeks' gestation. In all cases the Sylvian fissure was abnormal on both ultrasound and MRI. In one fetus, a normal cortical appearance for gestational age was seen at the initial 20-week ultrasound examination, but delayed cortical development was identified at a 24-week scan. Mild ventriculomegaly was seen in six fetuses and dysgenesis of the corpus callosum in one. Extracranial abnormalities were detected in five fetuses. Delayed cortical development was seen in two fetuses with mild ventriculomegaly, but no other fetal anomalies. CONCLUSIONS: In fetuses with MDS, delayed cortical development can be suspected on ultrasound as early as 23 weeks' gestation. This finding warrants further investigations including MRI and FISH analysis for chromosome 17p13.3 deletion.     

Sonography of fetal agenesis of the corpus callosum: a survey of 35 cases.

Agenesis of the corpus callosum was identified by ultrasound examination in 35 fetuses between 19 and 37 weeks' gestation. The ultrasound findings included absence of the corpus callosum and cavum septum pellucidum (hypoplasia in one case of partial agenesis of the corpus callosum), a typical 'teardrop' configuration of the lateral ventricles, distension of the interhemispheric fissure, upward displacement of the third ventricle, radiate arrangement of the medial cerebral gyri, and abnormal branching of the anterior cerebral artery. Associated anomalies were identified in 20 fetuses, including heterogeneous malformations and chromosomal aberrations (mosaic-trisomy 8 in three, trisomy 18 in two and partial duplication 8p in one). Five cases of agenesis of the corpus callosum were identified in a population of pregnant patients prospectively investigated because of genetic risk for agenesis of the corpus callosum or related syndromes. In this group, no diagnostic errors were made. Long-term neurological follow-up (6 months to 11 years) was available in 11 infants with antenatal diagnosis of isolated agenesis of the corpus callosum. Normal intellectual development was present in nine, and a low intellect (developmental quotient between 70 and 85) was found in two. It is concluded that fetal agencies of the corpus callosum is associated with elusive sonographic findings that can, however, be accurately identified by targeted examinations. In routine sonograms, an increased atrial width and/or failure to visualize the cavum septum pellucidum should arise the suspicion of fetal agencies of the corpus callosum. Given the high frequency of associated anomalies, prenatal diagnosis of agencies of the corpus callosum dictates the need for a careful survey of fetal anatomy and karyotyping. The prognosis is isolated agencies of the corpus callosum remains uncertain, although it is expected that a normal or boarderline intellectual development will occur in many cases.     

Prenatal detection of fetal trisomy 18 through abnormal sonographic features.

OBJECTIVE: To describe the prenatal detection of fetal trisomy 18 through abnormal sonographic features and to determine the sensitivity of sonographically detecting fetuses with trisomy 18. METHODS: All genetic and cytogenetic records of fetuses with trisomy 18 were reviewed retrospectively (1992-2002). From these, singleton fetuses who had prenatal sonography at our unit were identified. The maximal numbers of individual abnormalities from 1 sonographic examination (not limited to type of organ system) were recorded. Each abnormality was classified as major, minor, or "other," and each organ system was classified as abnormal only once, regardless of the number of individual abnormalities identified in that system. The sensitivity of sonography in detecting abnormalities of trisomy 18 was determined. RESULTS: Of 38 fetuses identified with trisomy 18, all had 4 or more prenatally detected sonographic abnormalities (sensitivity of sonographic detection of fetuses with trisomy 18, 100%). The median number of abnormalities per examination was 8 (range, 4-19). Sonographically detected major abnormalities were cardiac (84%; n = 32), central nervous system (87%; n = 33), gastrointestinal (26%; n = 10), and genitourinary (16%; n = 6). Sonographically detected minor abnormalities were short ear length below the 10th percentile for gestational age (96%; n = 26/27), upper extremities and hands (95%; n = 36), lower extremities and feet (63%; n = 24), and face (53%; n = 20). Fifty percent (19 of 38) had choroid plexus cysts identified, but this was never an isolated finding. CONCLUSIONS: In experienced hands, the sensitivity of detecting fetal trisomy 18 on prenatal sonography is 100%, and all cases will have multiple anomalies visualized.     

超声诊断胎儿胼胝体缺失的价值

目的：探讨胎儿胼胝体缺失声像图特征,认识超声在诊断胼胝体缺失中的价值。材料与方法：根据胎位不同,对胎头进行不同切面扫查,以显示胎头矢状切面为最佳,根据颅内结构的直接或间接影像明确诊断。结果：共8例患者经产前超声检查诊断为此类畸形。共同特征为：脑中线居中,双侧脑室前角狭窄,距脑中线距离增宽,后角扩张,整个侧脑室成＂泪滴状＂;双侧脑室成平行状;第三脑室扩张并上移;未见透明隔腔及胼胝体;侧脑室与脑中线之间显示脑回回声。8例均经MRI证实超声诊断。脐带血检查结果示1例染色体异常,为47,XN,＋18;余7例为46,XN。结论：胼胝体缺失是一种少见的脑部异常,可以发生在染色体异常病例中。通过产前超声检查对胎儿颅内结构特点进行分析,能够明确诊断此病,对临床工作具有指导意义。     

应用三维超声多平面重建技术评价胎儿胼胝体

目的探讨三维超声评价胎儿胼胝体的应用价值。方法分别应用二维和三维超声对87胎正常胎儿及7胎胼胝体发育不全胎儿进行超声检查。结果二维超声获得31胎正常胎儿的胎头矢正中切面,三维重建获得全部胎儿的胎头矢正中切面,二维与三维超声胼胝体图像基本一致,对胼胝体长度的测量高度相关。二维和三维超声均能诊断7胎胼胝体发育不全。结论二维矢正中切面图像质量较好,但三维矢正中切面较二维切面更易获得,可快速评价胎儿胼胝体结构,对产前常规筛查有很高的实用价值。