Role of fetal ultrasound and magnetic resonance imaging in the prenatal diagnosis of migration disorders

OBJECTIVES: To evaluate the contribution and limitations of fetal ultrasonography (US) and magnetic resonance imaging (MRI) for the diagnosis and management of migration disorders. METHODS: Over a 5-year period, 14 fetuses with pathological migration disorders, without an infectious context, were taken care of in our centre. All underwent US; nine underwent MRI as well. Sonographic and MRI data were compared with neuropathological data. RESULTS: The diagnosis of gyral disorders was obtained by US in 1/14 cases; other cerebral abnormalities were found suggesting neuronal disorder in the remainder. Cerebral MRI suggested gyral abnormality in eight of the nine cases. CONCLUSIONS: US performance is increasing. MRI appears to be a promising method for the diagnosis of fetal migration disorders, giving better results than US. It may be recommended in cases of abnormal cerebral US findings or familial clinical history. However, interpretation of MRI can be tricky and the resulting diagnosis occurs late within the pregnancy.     

Schizencephaly: prenatal diagnosis by computed sonography and magnetic resonance imaging

Magnetic resonance (MR) imaging was performed at 29 weeks of pregnancy after ultrasonographic detection of an abnormal cleft in the fetal brain. Fetal neuromuscular blockade was induced by pancuronium bromide injected into the umbilical vein under continuous ultrasound (US) guidance. MR images supported the echotomographic diagnosis of schizencephaly improving the visualization of symmetrical broad clefts connecting the lateral ventricles with the subarachnoid space. Schizencephaly was finally confirmed by neonatal US, computed tomography, and MR.     

Intrauterine brain teratoma: a case report of imaging (US,MRI) with neuropathologic correlations

Fetal brain tumors are rare and teratoma is considered as the most common. Fetal MR Imaging is currently used to evaluate cases of ventricular dilatation. We report a case of cerebral immature teratoma detected by ultrasonography because of ventricular dilatation at 24 gestational weeks. MRI was the more accurate imaging method in depicting the tumor and its consequences on brain development as well as in taking a decision with regard to the management of pregnancy.     

Fetal magnetic resonance imaging (MRI) of ischemic brain injury

The aim of the present study was to demonstrate the usefulness of fetal magnetic resonance imaging (MRI) in ischemic brain injury. We report seven cases of fetal brain ischemia prenatally suspected on ultrasound (US) and confirmed by fetal MRI. Sonographic abnormalities included ventricular dilatation (n=3), microcephaly (n=1), twin pregnancy with in utero death of a twin and suspected cerebral lesion in the surviving co-twin (n=3). MRI was performed with a 1.0 T unit using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences between 28 and 35 weeks of gestation. US and MRI images were compared with pathologic findings or postnatal imaging. MRI diagnosed hydranencephaly (n=1), porencephaly (n=2), multicystic encephalomalacia (n=2), unilateral capsular ischemia (n=1), corpus callosum and cerebral atrophy (n=1). In comparison with US, visualization of fetal brain anomalies was superior with MRI. The present cases demonstrate that MRI is a valuable complementary means of investigation when a brain pathology is discovered or suspected during prenatal US.     

Lobar holoprosencephaly: prenatal MR diagnosis with postnatal MR correlation

Holoprosencephaly is a congenital anomaly characterized by lack of cleavage of the prosencephalon. Although, relatively rare, it is the most common anomaly that involves both the brain and the face. Prenatal diagnosis of this anomaly using ultrasonography, particularly of the less severe forms, is difficult. Magnetic resonance imaging has recently become an important complement to US in prenatal diagnosis of CNS anomalies. We herein report a patient in whom, at 23 weeks of gestation, US suggested agenesis of the corpus callosum and in whom, at 24 weeks of gestation, MRI correctly diagnosed lobar holoprosencephaly, which was confirmed by a postnatal MRI at 3 weeks of age.     

Prenatal diagnosis of tuberous sclerosis with intracerebral signs at 14 weeks' gestation.

We report the ultrasound detection of cranial abnormalities at 14 weeks' gestation in a fetus subsequently confirmed as having tuberous sclerosis using DNA linkage analysis within the affected family. The presence of asymmetrical ventricular enlargement persisted antenatally. Magnetic resonance imaging at 26 weeks indicated the possibility of poor gyral formation consistent with a neuronal migration disorder. Cardiac rhabdomyomata were not visualized on ultrasound scan until 30 weeks' gestation. Postnatal cranial ultrasound confirmed the significant neuropathology which was manifested by severe developmental delay and intractable fits in the child. The potential benefits of earlier diagnosis of tuberous sclerosis by cranial imaging are discussed, although in this patient the routine booking scan resulted in a path of prenatal diagnosis being undertaken which had originally been declined. A mechanism is proposed to explain the variable expression of tuberous sclerosis within this family based on altered TSC2 activity affecting neuronal migration.     

Progressive neuronal degeneration of childhood: prenatal diagnosis by MRI

We report two cases in the same family of progressive neuronal degeneration of childhood--Alpers syndrome--with prenatal MRI findings in one case. The first infant presented at birth with severe microcephaly, then rapidly evolved to progressive encephalopathy with refractory epilepsy, leading to death at 10 months. Biochemical investigations including liver function tests were normal. CT and MRI showed severe diffuse brain atrophy. The diagnosis of progressive neuronal degeneration of childhood was made on the clinical and imaging data. The second pregnancy was marked by gradual decrease of fetal cerebral biometry and a prenatal MRI performed at 32 weeks showed diffuse cortical atrophy, as observed in the sibling. The infant died at 5 months. Neuropathological findings were consistent with Alpers syndrome.     

Magnetic resonance imaging of Ebstein's anomaly: report of two cases.

Among 388 cases of congenital heart disease with magnetic resonance imaging (MRI) from September 1990 to February 1992, we came across two cases of Ebstein's anomaly. They had been previously diagnosed as Ebstein's anomaly by echocardiography and cinecardioangiography. The first case was a three-year-old boy with complex congenital heart disease that included Ebstein's anomaly, a double-outlet right ventricle, pulmonary hypertension, tricuspid regurgitation, mitral regurgitation, a ventricular septal defect and an atrial septal defect. The second was a 13-year-old boy who also had Ebstein's anomaly, but had received a tricuspid valve replacement at the age of five. In Ebstein's anomaly, we found that MRI offers exquisite endocardial and epicardial details. We anticipate that in the future MRI will help to eliminate invasive studies.     

Comparison of magnetic resonance imaging and ultrasonography in the prenatal diagnosis of congenital thoracic abnormalities

OBJECTIVES: To evaluate prenatal MRI in the diagnosis of fetal thoracic abnormalities and to determine whether MRI provides useful information in addition to that of ultrasonography (US). METHODS: Ultrafast MR scanning was performed in 7 pregnant women in whom US was suspicious of fetal congenital anomalies of the thorax [3 cases of congenital diaphragmatic hernia (CDH), 3 cases of chylothorax and 1 case of congenital cystic adenomatoid malformation (CCAM) type III]. The presence, position, size and characteristics of the congenital lesions were determined and compared with postnatal diagnoses. RESULTS: The MRI diagnoses were 3 cases of CDH, 2 of chylothorax and one each of esophageal atresia and CCAM type III. The results of MRI were in agreement with those of US in 6 cases and in disagreement in 1 case of esophageal atresia. Final diagnoses were confirmed at surgery or autopsy in all fetuses. Combined use of MR and US imaging enabled a correct diagnosis in 5 cases and led to an error in the diagnosis of 1 fetus with bronchial stenosis, which had been diagnosed as CCAM type III by US and MRI. MRI led to a correct diagnosis in 1 fetus with esophageal atresia, in whom US had been equivocal in the prenatal diagnosis. CONCLUSION: MRI helped further characterize the fetal thoracic lesions and confirmed or changed the prenatal diagnosis based on US. MRI seems to be powerful in the prenatal diagnosis of thoracic lesions that are atypical or complicated by multiple abnormalities.     

Central nervous system abnormalities assessed with prenatal magnetic resonance imaging

OBJECTIVE: To determine the frequency at which magnetic resonance imaging (MRI) provides additional information in fetuses with suspected central nervous system (CNS) abnormalities on ultrasound. METHODS: Between May 1, 1996, and March 26, 1999, 83 women with 90 fetuses (including seven sets of live twins) had 91 ultrasonographic and MRI examinations of the fetal CNS. Eight women were studied twice, one for two different indications. If referrals came from outside our institution, a confirmatory sonogram was obtained. Indications for examination were ventriculomegaly (n = 25), suspected neural tube defect (n = 16), arachnoid cyst (n = 12), large cisterna magna (n = 11), and miscellaneous indications (n = 20). RESULTS: Magnetic resonance imaging findings led to changed diagnoses in 26 (40%) of 66 fetuses with abnormal confirmatory sonograms. Magnetic resonance imaging findings not found by ultrasound included partial or complete agenesis of the corpus callosum (n = 11), porencephaly (n = 6), hemorrhage (n = 5), tethered cord (n = 3), cortical gyral abnormality (n = 2), cortical cleft (n = 2), midbrain abnormality (n = 2), and partial or complete agenesis of the septi pellucidi (n = 3), as well as holoprosencephaly, cerebellar hypoplasia, subependymal and cortical tubers, vascular malformation, and vermian cysts (one case each). Abnormalities better delineated by MRI than ultrasound included three cephaloceles, a dural arteriovenous malformation, one distal sacral neural tube defect, and the mass effect of three arachnoid cysts. That information was used to alter patient counseling and at times management. CONCLUSION: When a CNS anomaly is detected by sonography or suspected on ultrasound, MRI findings might lead to altered diagnosis and patient counseling.     

Characteristic findings for diagnosis of baby complicated with both the VACTERL association and duodenal atresia

The VACTERL [vertebral defects (V), anal atresia (A), cardiac anomaly (C), tracheal-esophageal fistula with esophageal atresia (TE), renal defects (R), and radial limb dysplasia (L)] association can sometimes be diagnosed by ultrasonography and magnetic resonance imaging (MRI). Although the preaxial limb anomalies on ultrasonography were strongly associated with VACTERL association, the rate of limb anomalies is low. On ultrasonography, useful findings for prenatal diagnosis are a combination of esophageal atresia with hydramnion and renal anomalies. If esophageal atresia cannot be detected due to masking, diagnosis may be very difficult. In this case report, we reported the VACTERL association along with duodenal atresia. The detection of characteristic findings (enlarged stomach and duodenum, possibly change in gallbladder) by use of ultrasonography and MRI might be useful for the prenatal diagnosis of such cases.     

Magnetic resonance imaging and ultrasound in the assessment of the fetal central nervous system

Ultrasound is the screening modality of choice for evaluation of the fetal central nervous system (CNS). However, in cases of difficult diagnosis further fetal investigation is desirable. Due to ultrafast magnetic resonance imaging (MRI) techniques artifacts from fetal motions are minimized. MRI involves no exposure to radiation and hence appears to be safe. Due to the better soft tissue contrast, additional investigation by MRI may extend the sonographic diagnosis of fetal CNS-anomalies. Ultrasound and MRI are complementary imaging methods in the evaluation of the fetal CNS. The most important indications for ultrasound are screening for CNS anomalies and serial assessment of the dynamic of the disorder. The most important indications for fetal MRI are the "second opinion" and investigation by fetal MRI instead of postpartum MRI (especially in cases of planned postpartum intervention). In this article the indications and limitations of ultrasound and magnetic resonance imaging in the evaluation of the fetal CNS are discussed.     

Prenatal imaging of facial clefts by magnetic resonance imaging with emphasis on the posterior palate

OBJECTIVE: To evaluate the role of Magnetic Resonance Imaging (MRI) in the prenatal diagnosis of facial clefts. MATERIALS AND METHODS: Six fetuses with a sonographic diagnosis of cleft lip and palate underwent MRI at a median age of 30 weeks (range 28-32). The defect was bilateral in two cases. RESULTS: Fetal MRI confirmed the presence of a cleft involving at least the anterior palate in all cases. Distinction between unilateral and bilateral clefts could be made in all cases and was always confirmed after birth. Sagittal views of the fetal face were found to be particularly useful in identifying the degree of extension of the cleft into the palate. The diagnosis was confirmed after birth. CONCLUSION: Our results suggest that MRI may be ancillary to ultrasound in prenatal investigation of a fetus with cleft lip, allowing a better staging of the lesion by demonstrating the degree of involvement of the palate.     

Hemimegalencephaly: prenatal diagnosis and outcome

Hemimegalencephaly (HME) is a developmental abnormality of the central nervous system (CNS) which may present as either a syndromic or isolated case. Here, we present two cases of early prenatal diagnosis of HME. Prenatal CNS ultrasound and MRI in the first case revealed ventricular asymmetry, midline shift with displacement of the occipital lobe across the midline, large dilatation mainly at the posterior horn of the left lateral ventricle, and a head circumference in the 90th percentile without involvement of the brain stem and cerebellum, as well as abdominal lymphangioma. Right hemispherectomy was performed at 3 months of age due to intractable seizures. The pathological specimen showed findings characteristic of HME, including a disorganized cytoarchitecture with lack of neuronal lamination, focal areas of polymicrogyria, and neuronal heterotopias with dysplastic cells. In the second case, 2D and 3D neurosonography demonstrated similar findings (asymmetry of cerebral hemispheres, midline shift, and dilation of the posterior horn of the left lateral cerebral ventricle). Posterior fossa structures were unremarkable. HME was diagnosed and the pregnancy was terminated. Autopsy findings confirmed the diagnosis of HME.     

超声与磁共振成像诊断胎儿脊柱与脊髓发育异常的对照研究

目的 比较产前超声检查、磁共振成像(MRI)用于诊断胎儿脊柱与脊髓发育异常的临床价值.方法 选择产前超声检查显示胎儿脊柱与脊髓发育异常的30例孕妇(其中脊柱排列不规则19例、椎管局部增宽7例、脊柱曲度异常4例),年龄22～41岁,孕龄23～38周,在超声检查后72 h内行MRI检查.30例孕妇中选择引产者25例,选择继续妊娠者5例.经患者知情同意,对引产后患儿行尸体解剖(尸解,22例)或尸体影像学检查(3例);对选择继续妊娠者,新生儿出生后12个月内行MRI随访.结果 (1)诊断符合率:19例产前超声显示脊柱排列不规则的胎儿中,产前超声正确诊断8例,分别为3例脊膜膨出、1例隐形脊柱裂、1例脊髓脊膜膨出、3例半椎体,产前超声诊断正确率为42%(8/19);而MRI正确诊断17例,只有1例半椎体和1例蝴蝶椎未能明确诊断,MRI诊断符合率为89%(17/19).7例超声显示椎管局部增宽的胎儿中,产前超声正确诊断0例,符合率为0,MRI正确诊断7例,符合率为7/7.4例超声显示脊柱曲度异常的胎儿中,产前超声正确诊断2例,为尾退化综合征和颈椎过度反曲各1例,符合率为2/4,MRI正确诊断3例,只有1例背侧皮毛窦未能正确诊断,MRl诊断符合率为3/4.(2)MRI的优势:MRI与超声诊断一致9例、纠正超声诊断6例、确诊超声可疑的诊断1例、完善超声诊断11例,MRI和超声均漏诊半椎体、蝴蝶椎和背侧皮毛窦各1例.超声漏诊病例多为脊髓病变,且声像图表现无特异性.结论 MRI可直接显示脊髓及其病变,在评价胎儿脊柱与脊髓发育异常方面是对超声显像的补充,能显著提高诊断的准确性.     

Antenatal ultrasound findings in a case of Uhl's anomaly

A case of severe congenital Uhl's anomaly is described. Uhl's anomaly is a rare disorder characterized by near total absence of the right ventricular myocardium. Antenatal ultrasound and echocardiographic findings are presented and the differential diagnosis is discussed.     

Prenatal detection of a 1p36 deletion in a fetus with multiple malformations and a review of the literature

The prenatal diagnosis of a 1p36 deletion is reported. The pregnancy was ascertained at 24 weeks of gestation because of the discovery of multiple malformations at ultrasound including hypotelorism, moderate cerebral ventricular dilatation and Ebstein anomaly with secondary cardiac failure. Following cytogenetic studies and counselling, the pregnancy was terminated and a fetal autopsy performed. The phenotype of this antenatally-diagnosed case is compared with the clinical features of 44 previously reported cases with an identical deletion of the short arm of chromosome 1p36.     

Prenatal diagnosis of a cystic type IV sacrococcygeal teratoma mimicking a cloacal anomaly: contribution of MR

OBJECTIVE: To report a case of pelvic midline cystic mass in a female fetus without visibility of the rectum and which is not a cloacal anomaly. METHODS: Ultrasound (US) and magnetic resonance imaging (MRI) were performed respectively at 27 and 27.5 weeks' gestation and the findings of these examinations were compared with post-mortem examination after termination of pregnancy (TOP). RESULTS: US showed a pelvic midline cystic mass in a female fetus with mild enlargement of the left ureter and renal pelvis. MRI did not show the T1 hypersignal of meconium in the rectum. The analysis of MR findings were suggestive of the diagnosis of a sacrococcygeal teratoma. Pregnancy was terminated because of the possibility of severe sphincterial disorders and the fetopathological examination confirmed this diagnosis. CONCLUSION: This observation illustrates the diagnostic problems generated by the detection of a pelvic midline cystic mass in a female fetus. The absence of visibility of the T1 hypersignal of the meconium in the rectum is traditionally supposed to be highly suggestive of a cloaca, but may also be explained by the emptiness of the rectum, compressed by the mass.     

磁共振成像在产科临床的应用研究

目的探讨磁共振成像技术在产科中的应用价值。方法对2006年3月至2007年9月在中国医科大学附属盛京医院诊治的胎儿异常及产科并发症、合并症136例孕产妇的超声及磁共振结果,并结合术中所见和手术后病理结果进行对比分析。结果136例孕妇中MRI检查胎儿异常118例,产前胎盘异常5例,妊娠合并肿瘤9例,晚期产后出血4例。磁共振检查补充诊断率53.7%(73例),诊断符合率为46.3%(63例)。结论磁共振成像技术是对超声检查发现的胎儿、胎盘异常及妊娠合并肿瘤的定位、性质的重要验证和补充诊断手段。     

The impact of presurgical magnetic resonance in early breast cancer: an observational study

The aim of this study was to evaluate the impact of presurgical breast magnetic resonance imaging (MRI) on the surgical management of selected patients with early-stage breast cancer who were candidates for BCT. The sample was built up according to the EUSOMA (European Society of Breast Cancer Specialists) recommendations enrolling women with unifocal unilateral early-stage breast carcinoma diagnosed by mammography, ultrasound (US) examination and in some cases also by histological analysis; all were scheduled for wider local excision. All eligible patients underwent presurgical breast MRI and findings were classified according to the BI-RADS system. In the presence of additional foci classified as BI-RADS 3-4, a targeted second-look US study was performed. If second-look US confirmed the presence of foci, needle biopsy was performed. Possible changes in the therapeutic approach resulting from preoperative MRI findings were decided upon by a multidisciplinary team. Outcome of histological examination of the surgical specimen and particularly analysis of tumor infiltration of the resection margins was the standard for determining the appropriateness of surgical strategy. A total of 123 patients underwent presurgical breast MRI. Additional foci were detected in 41.6% of patients, a greater local extension of the index lesion in 6.4%, whereas MRI confirmed local staging established by conventional imaging in 52%. However, 13.8% of additional foci were not confirmed by second-look and needle biopsy. More extensive surgery as a result of MRI findings was performed in 34.2%. This decision proved to be appropriate in 29.3% thus resulting in an over-treatment rate of 4.9%. Presurgical breast MRI resulted in confirmation of planned surgical strategy in 65.8% with an appropriateness rate of 54.5%. Surgical resection margins were positive for malignancy in 11.3% and repeated surgery was therefore required. Therapeutic strategy established on the basis of MRI was appropriate in 83.8% of cases. This study confirms the utility of MRI in presurgical workup of selected breast cancer patients. The results obtained suggest the importance of a sensitive tool such as MRI in the local staging of breast cancer before treatment planning.