Fetal magnetic resonance imaging in the prenatal diagnosis of cerebellar hemorrhage.

We report the case of a fetus with a sonographic mid-gestation diagnosis of hyperechogenic cerebellum suspected to be of hemorrhagic origin on fetal brain magnetic resonance imaging (MRI). No etiological factors for fetal hemorrhage were found other than a maternal heterozygocity for factor V Leiden. Following termination of the pregnancy, autopsy confirmed the prenatal diagnosis of massive cerebellar hemorrhage without underlying vascular anomaly. As an additional tool to ultrasonography, fetal brain MRI can affirm the hemorrhagic origin of hyperechogenic cerebellar lesions, especially by showing a high signal on T1-weighted images.     

产前超声联合磁共振成像诊断胎儿膀胱外翻

目的总结胎儿膀胱外翻（BE）产前超声（US）及磁共振成像（MRI）影像特征。 方法对2013年2月至2017年12月在湖北省妇幼保健院产前超声联合MRI诊断并经产后病理检查确诊为膀胱外翻4例（3例单胎为自然受孕,1例双胎为人工受孕）胎儿的超声影像表现进行总结。 结果4例胎儿产前超声显示共有的异常声像表现为：盆腔内膀胱未显示,脐带低置,耻骨联合分离,性别难以确定,羊水量正常;其中1例双胎之一合并右肾缺如伴脐带插入处下方膨出物,1例疑诊脊髓栓系。4例胎儿产前MRI显示与超声相同的异常影像表现,但4例耻骨联合分离均未显示,排除了超声疑诊脊髓栓系。与引产后X线及病理检查结果对照,产前MRI补充检出超声未显示的腹壁缺损4例,且较超声多检出下腹部肿块凸出3例。超声与MRI联合检查正确诊断胎儿膀胱外翻4例。盆（腹）腔内无膀胱显示,下腹壁缺损伴包块突出,脐带低置,耻骨联合分离,外生殖器畸形,肾脏和羊水量正常为产前超声及MRI诊断胎儿膀胱外翻的主要线索。 结论产前超声与MRI联合检查有利于明确诊断膀胱外翻,避免漏诊。     

Real-time magnetic resonance imaging aids prenatal diagnosis of isolated cleft palate.

OBJECTIVE: Cleft of the secondary palate without cleft lip is difficult to visualize sonographically. This study was performed to assess the utility of sonography, standard magnetic resonance (MR) imaging, and real-time MR imaging in the diagnosis of isolated cleft palate. METHODS: We prospectively assessed 5 fetuses at risk for isolated cleft palate on the basis of family history, micrognathia, or both, using sonography and standard and real-time single-shot fast spin echo MR sequences. Written informed consent was obtained under our Institutional Review Board-approved Health Insurance Portability and Accountability Act-compliant protocol. Images were assessed for confidence in a diagnosis of cleft or normal palate. Prenatal and postnatal diagnoses were compared. RESULTS: In 3 fetuses, micrognathia was visualized by sonography and MR imaging with standard and real-time sequences. One fetus at 19 weeks had a wide cleft of the entire secondary palate, and another fetus at 33 weeks had a cleft of the soft palate; these defects were seen only with real-time MR imaging. One 35-week gestational age fetus had a cleft soft palate that was visualized on standard and real-time MR imaging. Two fetuses with no abnormalities had the normal midline secondary palate seen only on real-time MR imaging. In all fetuses, real-time images were helpful in assessing the secondary palate because the entire midline naso-oropharynx could be visualized. CONCLUSIONS: Real-time MR imaging allows for rapid assessment of the midline structures, providing accurate diagnosis of isolated cleft palate.     

Epignathus: prenatal diagnosis by sonography and magnetic resonance imaging

Prenatal diagnosis of a teratoma of the oral cavity (epignathus) is presented using ultrasonography and magnetic resonance imaging as complementary techniques. Chromosome analysis from amniotic fluid revealed an inverted duplication of chromosome 1 that was confined to the tumour, whereas the constitutional karyotype was normal. The development of polyhydramnios, presumably reflecting impaired fetal swallowing, led to premature rupture of membranes and spontaneous delivery at 23 + 4 weeks of pregnancy. The premature neonate succumbed to acute respiratory distress secondary to airway obstruction by the tumour, and died immediately after birth.     

Ultrasound and fetal magnetic resonance imaging: Clinical performance in the prenatal diagnosis of orofacial clefts and mandibular abnormalities

Cleft lip, with or without cleft palate, is the most common congenital craniofacial anomaly and the second most common birth defect worldwide. Micrognathia is a rare facial malformation characterized by small, underdeveloped mandible and frequently associated with retrognathia. Second- and third-trimester prenatal ultrasound is the standard modality for screening and identification of fetal orofacial abnormalities, with a detection rate in the low-risk population ranging from 0% to 73% for all types of cleft. The prenatal ultrasonography detection can also be performed during the first trimester of pregnancy. Given the potential limitations of obstetric ultrasound for examining the fetal face, such as suboptimal fetal position, shadowing from the surrounding bones, reduce amniotic fluid around the face, interposition of fetal limbs, umbilical cord and placenta, and maternal habitus/abdominal scars, the use of adjunct imaging modalities can enhance prenatal diagnosis of craniofacial anomalies in at-risk pregnancies. Fetal magnetic resonance imaging (MRI) is a potentially useful second-line investigation for the prenatal diagnosis of orofacial malformations with a pooled sensitivity of 97%. In this review, we discuss the role of ultrasound and fetal MRI in the prenatal assessment of abnormalities of the upper lip, palate, and mandible.     

Usefulness of prenatal magnetic resonance imaging in differential diagnosis of fetal congenital cystic adenomatoid malformation and bronchopulmonary sequestration

BACKGROUNDCongenital cystic adenomatoid malformation (CCAM) and bronchopulmonary sequestration (BPS) are the most common lung diseases in fetuses. There are differences in the prognosis and treatment of CCAM and BPS, and the clinical diagnosis and treatment plan is usually prepared prior to birth. Therefore, it is quite necessary to make a clear diagnosis before delivery. CCAM and BPS have similar imaging features, and the differentiation mainly relies on the difference in supply vessels. However, it is hard to distinguish them due to invisible supplying vessels on some images.AIMTo explore the application value of magnetic resonance imaging (MRI) in the differential diagnosis of fetal CCAM and BPS.METHODSData analysis for 32 fetuses with CCAM and 14 with BPS diagnosed by prenatal MRI at Huzhou Maternal and Child Health Care Hospital and Anhui Provincial Children’s Hospital from January 2017 to January 2020 was performed to observe the source blood vessels of lesions and their direction. Pathological confirmation was completed through CT examination and/or operations after birth. RESULTSAfter birth, 31 cases after birth were confirmed to be CCAM, and 15 were confirmed to be BPS. The CCAM group consisted of 21 macrocystic cases and 10 microcystic cases. In 18 cases, blood vessels were visible in lesions. Blood supply of the pulmonary artery could be traced in eight cases, and in 10 cases, only vessels running from the midline to the lateral down direction were observed. No lesions were found in four macrocystic cases and one microcystic case with CCAM through CT after birth; two were misdiagnosed by MRI, and three were misdiagnosed by prenatal ultrasonography. The BPS group consisted of 12 intralobar cases and three extralobar cases. Blood vessels were visible in lesions of nine cases, in four of which, the systemic circulation blood supply could be traced, and in five of which, only vessels running from the midline to the lateral up direction were observed. Three were misdiagnosed by MRI, and four were misdiagnosed by prenatal ultrasonography. CONCLUSIONCCAM and BPS can be clearly diagnosed based on the origin of blood vessels, and correct diagnosis can be made according to the difference in the direction of the blood vessels, but it is hard distinguish microcystic CCAM and BPS without supplying vessels. In some CCAM cases, mainly the macrocystic ones, the lesions may disappear after birth.     

The fetal posterior fossa: clinical correlation of findings on prenatal ultrasound and fetal magnetic resonance imaging

OBJECTIVES: Recognize posterior fossa anomalies on ultrasound and magnetic resonance imaging and appreciate imaging pitfalls that may lead to misdiagnosis. MATERIALS AND METHODS: Cases are presented to illustrate normal development and various anomalies. Postnatal studies and autopsy are used for correlation with prenatal imaging. RESULTS: Normal anatomy and anomalies are demonstrated. Pitfalls such as cystic hygroma, pseudomasses, and use of nonstandard scan planes are illustrated. CONCLUSIONS: Recognizing normal developing structures is an important component of performing fetal ultrasound. Documentation of the cerebellum, vermis, and cisterna magna are required for posterior fossa evaluation in any American Institute of Ultrasound in Medicine-certified practice. Normal variations are common, and understanding the anatomy is vital to avoid misdiagnosis and to accurately characterize abnormalities.     

肛管高空间分辨率磁共振成像的应用价值探讨

目的探讨肛管的高空间分辨率磁共振成像方法及其临床应用价值。方法20例无肛肠病变的志愿者行MR快速高分辨率自旋回波序列T1WI和T2WI扫描,并对获得图像进行分级评价和定量分析。结果20例志愿者的内括约肌、纵行肌、外括约肌、耻骨直肠肌、括约肌间隙、坐骨肛门窝、肛提肌、肛管的黏膜层、黏膜下层等解剖结构均能清楚显示,肛管的信噪比SNR和肛管-脂肪对比度噪声比CNR分别为9.7±2.3和3.1±2.1。结论肛管的高空间分辨率磁共振成像可清晰显示肛管和括约肌环及其周围解剖结构,对于临床评价肛管及肛周病变具有重要的意义。     

高分辨率磁共振血管壁成像在评估颅内动脉瘤稳定性中的研究进展

传统的影像学技术如数字减影血管造影术(digital subtraction angiography,DSA)、CT血管造影术(computed tomography angiography,CTA)及磁共振血管造影术(magnetic resonance angiography,MRA),对颅内动脉瘤的检出、定位及形态学的评估具有一定优势,而对动脉瘤本身血管特征的评估存在很大的局限性。近年来,高分辨率磁共振血管壁成像(high resolution magnetic resonance vessel wall imaging,HR-VWI)逐渐应用于动脉管壁结构的观察与分析,与血管壁的病理特征相结合,对颅内动脉瘤的稳定性进行直接定性评估。笔者将对HR-VWI技术在不同类型颅内动脉瘤中的应用进行综述。     

Fast fetal magnetic resonance imaging techniques

New hardware and software allow for increased magnetic resonance imaging (MRI) speed. This speed is crucial for MRI of the fetus, where motion degrades image quality. Single-shot sequences such as echo-planar and single-shot fast spin echo now are practical with most clinical scanners. This article reviews and illustrates the physics of fast magnetic resonance sequences.     

产前超声在诊断胎儿肿瘤及判定预后中的作用

目的总结胎儿肿瘤的产前超声表现特点,探讨产前超声在胎儿肿瘤诊断和临床预后中的价值。方法回顾分析65例经病理或其他影像学方法证实的胎儿肿瘤的产前超声表现及临床随访资料。结果胎儿肿瘤颅内8例,面部2例,颈部22例,胸部10例,腋窝2例,腹部及腹膜后11例,骶尾部2例,肢体2例,胎盘6例。临床结局:终止妊娠34例,胎死宫内3例,婴幼儿存活28例。结论产前超声检查及动态随访对胎儿肿瘤的诊断、预后判断及临床处理具有重要作用。     

Identification of cortical lamination in awake monkeys by high resolution magnetic resonance imaging

Brodmann divided the neocortex into 47 different cortical areas based on histological differences in laminar myeloarchitectonic and cytoarchitectonic defined structure. The ability to do so in vivo with anatomical magnetic resonance (MR) methods in awake subjects would be extremely advantageous for many functional studies. However, due to the limitations of spatial resolution and contrast, this has been difficult to achieve in awake subjects. Here, we report that by using a combination of MR microscopy and novel contrast effects, cortical layers can be delineated in the visual cortex of awake subjects (nonhuman primates) at 4.7 T. We obtained data from 30-min acquisitions at voxel size of 62.5 × 62.5 × 1000 μm³ (4 nl). Both the phase and magnitude components of the T₂*-weighted image were used to generate laminar profiles which are believed to reflect variations in myelin and local cell density content across cortical depth. Based on this, we were able to identify six layers characteristic of the striate cortex (V1). These were the stripe of Kaes-Bechterew (in layer II/III), the stripe of Gennari (in layer IV), the inner band of Baillarger (in layer V), as well as three sub-layers within layer IV (IVa, IVb, and IVc). Furthermore, we found that the laminar structure of two extrastriate visual cortex (V2, V4) can also be detected. Following the tradition of Brodmann, this significant improvement in cortical laminar visualization should make it possible to discriminate cortical regions in awake subjects corresponding to differences in myeloarchitecture and cytoarchitecture.