A novel RYR1 variant in an infant with a unique fetal presentation of central core disease.

Ryanodine receptor type 1-related disorder (RYR1-RD) is the most common subgroup of congenital myopathies with a wide phenotypic spectrum ranging from mild hypotonia to lethal fetal akinesia. Genetic testing for myopathies is imperative as the diagnosis informs counseling regarding prognosis and recurrence risk, treatment options, monitoring, and clinical management. However, diagnostic challenges exist as current options are limited to clinical suspicion prompting testing including: single gene sequencing or familial variant testing, multi-gene panels, exome, genome sequencing, and invasive testing including muscle biopsy. The timing of diagnosis is of great importance due to the association of RYR1-RD with malignant hyperthermia (MH). MH is a hypermetabolic crisis that occurs secondary to excessive calcium release in muscles, leading to systemic effects that can progress to shock and death if unrecognized. Given the association of MH with pathogenic variants in RYR1, a diagnosis of RYR1-RD necessitates an awareness of medical team to avoid potentially triggering agents. We describe a case of a unique fetal presentation with bilateral diaphragmatic eventrations who had respiratory failure, dysmorphic facial features, and profound global hypotonia in the neonatal period. The diagnosis was made at several months of age, had direct implications on her clinical care related to anticipated need to long-term ventilator support, and ultimately death secondary an arrhythmia as a result of suspected MH. Our report reinforces the importance of having high suspicion for a genetic syndrome and pursuing early, rapid exome or genome sequencing as first line testing in critically ill neonatal intensive care unit patients and further evaluating the pathogenicity of a variant of uncertain significance in the setting of a myopathic phenotype.

Utilization of 3-T fetal magnetic resonance imaging in clinical practice: a single-institution experience.

BACKGROUND: As the safety and efficacy of fetal magnetic resonance imaging (MRI) at 3 tesla (T) continues to evolve, understanding its potential benefits and limitations is becoming increasingly important. OBJECTIVE: We aim to compare the image quality of fetal MRI between 1.5 T and 3 T in routine clinical practice. MATERIALS AND METHODS: Fetal MRIs performed at 3 T between Jan. 1, 2019, and Dec. 31, 2019, at our institution were retrospectively reviewed by four fellowship-trained subspecialty radiologists. Imaging quality by system, sequence and artifacts were compared with matched controls at 1.5 T and rated using a modified Likert scale. RESULTS: Thirty-three fetal MRIs at 3 T were reviewed, and a control group of studies for the same clinical indication and equivalent gestational age were selected for comparison. Two of the four radiologists preferred 3-T image quality of the brain with slight agreement among the four reviewers (k=0.19, P=0.01). Three of the four radiologists had no preference for 1.5 T vs. 3 T in the majority of cases in evaluating the chest and abdomen. In the overall assessment, 3 T was preferred in less than half of cases by all four radiologists (k=0.07, P=0.26). In the evaluation of standing wave, moire fringe and magnetic susceptibility artifacts, 3 T was not preferred in the majority of studies by all four radiologists. Total exam time was significantly longer in the 3-T fetal MRIs (75.0±15.1 min) compared to the 1.5-T fetal MRIs (55.5±13.3 min, P<0.001). CONCLUSION: While 3 T is a feasible alternative to 1.5 T for fetal MRI, the increased artifacts and longer exam times observed at 3 T without clear improvement in overall image quality make 1.5 T preferable for fetal MRI in routine clinical practice.

Magnetic resonance imaging of the fetal brain in monochorionic diamniotic twin gestation: correlation of cerebral injury with ultrasound staging and survival outcomes.

BACKGROUND: The current staging system of twin-twin transfusion syndrome (TTTS) is based on the ultrasound criteria and does not consider the cerebral injury. OBJECTIVE: To assess the incidence of cerebral damage on fetal MRI and correlate abnormal cerebral diffusion-weighted imaging (DWI) findings with survival outcome and the ultrasound staging of TTTS. MATERIALS AND METHODS: We conducted a retrospective review of MRI/DWI of fetal brains and the electronic medical records in monochorionic diamniotic twin gestations. Axial DWI of each fetal brain was performed on 1.5-tesla (T) clinical magnet with b values of 0 s/mm2 and 700 s/mm2. We correlated MRI/DWI abnormalities with the Quintero staging system and survival outcomes of the fetuses. RESULTS: Thirty-four pregnancies (68 fetuses) with 42 fetal cerebral abnormalities were identified by MRI/DWI alone. Of these 42 fetal cerebral abnormalities, 33 fetal brain lesions were visible only on DWI (n=25 donor, n=8 recipients; n=30 unilateral, n=3 bilateral; n=26 diffuse, n=7 focal). Quintero staging in these 34 pregnancies was as follows: 9 Stage I, 7 Stage II, 13 Stage III, 4 Stage IV, 1 Stage V. There was no significant correlation between the presence of cerebral infarction or hemorrhage using MRI/DWI and ultrasound staging (P=0.138). The overall survival rate was 63.2% (43/68). There was a significant correlation between the presence of cerebral infarction or hemorrhage on MRI/DWI and delivery status (P=0.009). CONCLUSION: Abnormal cerebral imaging findings on MRI/DWI from hypoxic-ischemic injury or hemorrhage can be seen at the beginning of the second trimester and do not correlate with the current ultrasound staging system; however, they do correlate with decreased survival. Fetal cerebral abnormalities could be incorporated into the TTTS staging system as an independent risk factor.

Fetal magnetic resonance imaging of skeletal dysplasias.

BACKGROUND: Fetal magnetic resonance imaging (MRI) is obtained for prenatal diagnosis and prognostication of skeletal dysplasias; however, related literature is limited. OBJECTIVE: The purpose of this study was to define the utility of fetal MRI for skeletal dysplasias and to report MRI findings associated with specific diagnoses. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board; informed consent was waived. Women referred for suspected fetal skeletal dysplasia who underwent MRI between January 2003 and December 2018 were included. Definitive diagnoses were determined by genetic testing, autopsy, physical examination and/or postnatal/postmortem imaging. Fetal MRI examinations and reports were reviewed. Descriptive statistics were used to summarize imaging findings. RESULTS: Eighty-nine women were referred for fetal MRI for possible skeletal dysplasia. Forty-three (48%) were determined to have a diagnosis other than skeletal dysplasia and nine were excluded for lack of specific skeletal dysplasia diagnosis. Thirty-seven cases of skeletal dysplasia with available fetal MRI and specific diagnosis were included for analysis. Diagnoses included achondrogenesis (n=2), achondroplasia (n=5), Boomerang dysplasia (n=1), campomelic dysplasia (n=2), Jeune syndrome (n=1), Kniest dysplasia (n=1), osteogenesis imperfecta (n=15) and thanatophoric dysplasia (n=10). A specific skeletal dysplasia diagnosis was mentioned in 17/37 (46%) of MRI imaging reports and correct for 14/17 (82%). MRI findings were reported for each specific skeletal dysplasia diagnosis. CONCLUSION: Fetal MRI is a useful diagnostic tool for skeletal dyplasias and excluded the diagnosis in nearly half of referred pregnancies. In addition to providing fetal lung volumes, fetal MRI demonstrates findings of the brain in achondroplasia and thanatophoric dysplasia, of the spine in achondroplasia and achondrogenesis, of the calvarium in osteogenesis imperfecta and thanatophoric dysplasia, and of the cartilage in Kniest dysplasia.

Abnormalities Associated With the Cavum Septi Pellucidi on Fetal MRI: What Radiologists Need to Know.

OBJECTIVE: Screening the cavum septi pellucidi (CSP), more commonly referred to as the "cavum septum pellucidum," is a required component of the fetal anatomic survey during second-trimester ultrasound (US). The inability to identify the normal appearance of this structure warrants further evaluation because septal insufficiency is associated with multiple brain malformations. In this article, we discuss embryology, normal anatomy, and prenatal evaluation of the CSP as well as the differential diagnosis of associated abnormalities. CONCLUSION: The CSP is an essential part of the CNS evaluation on second-trimester US; if its normal appearance cannot be confirmed by 20 weeks' gestational age, further evaluation is warranted. Fetal MRI, in either the second or third trimester, has become an important tool in further characterization of the associated abnormalities. However, when fetal MRI is not possible, postnatal MRI can also be used and will help to differentiate primary from secondary absence and will aid in providing prognostic information and therapeutic options for patients.

Decreased rectal meconium signal on MRI in fetuses with open spinal dysraphism.

OBJECTIVE: To evaluate rectal meconium signal in fetuses with open spinal dysraphism and correlate findings with postnatal exam. METHODS: This is a single-institution Institutional Review Board-approved Health Insurance Portability and Accountability Act (HIPAA) compliant retrospective analysis of fetal MRIs of open spinal dysraphism from 2004 to 2016. Fetuses with diagnostic T1-weighted images and postnatal follow-up at our institution were included. RESULTS: A total of 115 fetuses (average gestational age 23.9 ± 3.6 weeks) met inclusion criteria. Of these, 80% (92/115) had T1 hyperintense rectal meconium signal. Average height of the meconium column, measured from the base of the bladder to its most inferior extent, was 9.2 ± 4.3 mm in fetuses ≥20-week gestational age and 11.1 ± 4.4 mm in fetuses ≥23-week gestational age (n = 110) . None had bowel dilation. One of 115 fetuses had a simple form of anorectal malformation allowing complete repair in the neonatal period, but this fetus had a normal meconium column height on fetal MRI of 22 mm. The remaining 23/115 fetuses with lack of normal rectal meconium signal were born without evidence of anorectal malformation. CONCLUSION: Decreased or absent T1-hyperintense rectal meconium signal in fetuses with open spinal dysraphism does not correlate with imperforate anus postnatal and may be a reflection of neurogenic bowel in this patient population.

Congenital aqueduct stenosis: Progressive brain findings in utero to birth in the presence of severe hydrocephalus.

PURPOSE: To evaluate the effects of progressive hydrocephalus on the developing brain in a cohort of fetuses diagnosed with congenital aqueduct stenosis by comparing prenatal magnetic resonance imaging and postnatal imaging. METHODS: This IRB approved single center retrospective review of prenatally diagnosed children with congenital aqueduct stenosis interrogated changes in the brain between prenatal and postnatal imaging and analyzed statistics using SAS software package version 9.3. RESULTS: Thirty fetuses imaged at a mean gestational age of 26 weeks had aqueduct obstruction confirmed by postnatal imaging. Progressive hydrocephalus required shunting in all but one patient (97%). Those patients with increasing hydrocephalus showed increase in ventricular rupture (60%), loss of septal leaflets (47%), and reduction in white matter and corpus callosum volume (43%). Cerebellar ectopia developed in 27% with 6% meeting the criteria for Chiari I malformation. CONCLUSION: Hydrocephalus in the fetus results in enlarging ventricular rupture, loss of the septum pellucidum leaflets, volume reduction of brain parenchyma including corpus callosum, and risk for Chiari I anomaly. Given advances in fetal surgery and imaging in the last 3 decades, there may be cause to revisit the idea of in utero cerebral spinal fluid diversion as a means to potentially ameliorate progressive loss of the developing brain.

Prenatal aqueduct stenosis: Association with rhombencephalosynapsis and neonatal outcome.

BACKGROUND AND PURPOSE: To examine prenatal MRI and postnatal imaging in fetuses with congenital aqueductal stenosis (CAS) to determine the frequency of association of rhombencephalosynapsis (RES) and how it may affect neonatal intensive care unit (NICU) course. MATERIALS AND METHODS: A single center IRB-approved retrospective study of children with CAS was performed. Prenatal MRI, postnatal images, and clinical data were reviewed. Statistical analysis was performed with SAS statistical software package version 9.3. RESULTS: Aqueduct obstruction was confirmed for all 30 participants. Hydrocephalus required shunting in all but one (97%). Fifteen neonates had CAS with rhomboencephalosynapsis (RES) (50%). Although neonatal course between the two groups was comparable, 53% of CAS with RES neonates required feeding assistance versus 20% in CAS only (P = 0.128). Shunting in the CAS with RES group occurred at average of 6 days of life versus CAS group at 55 days (P = 0.196). Biometry measurements showed a statistically significant decrease in pons antero-posterior diameter in both groups (CAS only P = 0.0049 and CAS with RES P = 0.0003) when compared with norms for gestational age. CONCLUSION: CAS has a high association with RES. Feeding assistance in the NICU and earlier neurosurgical intervention may be required in patients with CAS who also have RES.

Fowler syndrome and fetal MRI findings: a genetic disorder mimicking hydranencephaly/hydrocephalus.

Fetal ventriculomegaly is a common referral for prenatal MRI, with possible etiologies being hydrocephalus and hydranencephaly. The underlying cause of hydranencephaly is unknown, but many have suggested that the characteristic supratentorial injury is related to idiopathic bilateral occlusions of the internal carotid arteries from an acquired or destructive event. Fowler syndrome is a rare genetic disorder that causes fetal akinesia and a proliferative vasculopathy that can result in an apparent hydranencephaly-hydrocephaly complex. On prenatal imaging, the presence of significant parenchymal loss in the supratentorial and infratentorial brain is a clue to the diagnosis, which should prompt early genetic testing.

Congenital overinflation: prenatal MRI and US findings and outcomes.

OBJECTIVE: The purpose is to describe fetal MR and US findings of congenital overinflation (CO) and to correlate with postnatal outcome. METHODS: Two radiologists reviewed fetal MR and US images in 25 fetuses diagnosed with CO. Lesion size, appearance, location, and presence of hydrops were documented. Chart review was performed for pregnancy outcome, postnatal imaging, interventions, histopathology, and clinical outcome. RESULTS: All lesions demonstrated primarily homogeneous increased echogenicity and MR signal with absent pulmonary vascular distortion. A tubular cystic hilar structure was consistent with a dilated bronchus (68% MR, 25% US). The right lower (32%) and left lower (23%) lobes were most commonly involved. Two cases with central bronchial obstruction resulted in perinatal demise. Of 23 live births, 17 were asymptomatic, 1 symptomatic, and 5 lost to follow-up. Postnatal CT was performed in 17 of 18 patients confirming CO. Histopathology in nine patients revealed bronchial anomalies with hyperinflated (n = 7) or polyalveolar lung (n = 2). Nine patients were observed and remained asymptomatic. CONCLUSIONS: Fetal MR and US demonstrate a consistent pattern of imaging findings in fetuses with CO. Many cases are asymptomatic and can be managed with nonsurgical conservative therapy. CO because of central bronchial obstruction is associated with a guarded prognosis. © 2016 John Wiley & Sons, Ltd.

Guidelines for scanning twins and triplets with US and MRI.

Multiple-fetus gestations have an increased risk of discordant anomalies, aneuploidy and growth restriction compared to singleton pregnancies. In addition, twins sharing the same placenta are at risk for developing specific conditions that are potentially amenable to surgical management. In those scenarios, patients might need to be evaluated not only with US but with fetal MRI as well. This paper outlines basic guidelines to consider when imaging complicated multiple-fetus gestations during the 2nd and 3rd trimesters.

Prenatal Diagnosis of Infantile Myofibroma with Postnatal Imaging Correlation.

Infantile myofibroma is the most common fibrous tumor in infancy. A majority of these lesions are solitary and occur in the head and neck region. Unless visceral sites are involved, the clinical course is typically benign. However, the difficulty in these cases is the differentiation of a benign myofibroma from a solitary malignant neoplasm and determination of visceral involvement. Prenatal diagnosis of this condition is rarely described in the literature, but it does indeed have a role in perinatal management. Our patient was initially identified by prenatal ultrasound with fetal MRI for further characterization of the mass. We present the case of a prenatally diagnosed solitary infantile myofibroma of the lower extremity and highlight the role of prenatal imaging in the diagnosis and treatment of this condition.

Congenital salivary gland anlage tumor - in utero and postnatal imaging.

We present a case of an infant with congenital salivary gland anlage tumor, with fetal and postnatal imaging. To the best of our knowledge, this is the first case describing the in utero imaging findings of salivary gland anlage tumor. A fetal MRI was performed secondary to the clinical finding of polyhydramnios, which identified a nasopharyngeal mass. Because findings were concerning for airway obstruction, the fetus was delivered by ex utero intrapartum treatment (EXIT) to airway procedure. A postnatal CT confirmed the findings of the fetal MRI. The lesion was resected when the baby was 4 days old and recovery was uneventful.

Imaging evaluation of fetal vascular anomalies.

Vascular anomalies can be detected in utero and should be considered in the setting of solid, mixed or cystic lesions in the fetus. Evaluation of the gray-scale and color Doppler US and MRI characteristics can guide diagnosis. We present a case-based pictorial essay to illustrate the prenatal imaging characteristics in 11 pregnancies with vascular malformations (5 lymphatic malformations, 2 Klippel-Trenaunay syndrome, 1 venous-lymphatic malformation, 1 Parkes-Weber syndrome) and vascular tumors (1 congenital hemangioma, 1 kaposiform hemangioendothelioma). Concordance between prenatal and postnatal diagnoses is analyzed, with further discussion regarding potential pitfalls in identification.

Congenital peribronchial myofibroblastic tumor: prenatal imaging clues to differentiate from other fetal chest lesions.

We present a prenatal case of congenital peribronchial myofibroblastic tumor referred as a congenital pulmonary airway malformation (CPAM) with hydrops and polyhydramnios at 30 weeks' gestational age. US and fetal MRI findings did not fit with the referral diagnosis, raising the possibility of intrinsic lung tumor. Fetal hydrops worsened and the baby was successfully delivered by ex utero intrapartum treatment (EXIT) to resection at 31 weeks' gestational age. To the best of our knowledge, this is a unique case of congenital peribronchial myofibroblastic tumor that underwent comprehensive prenatal evaluation and EXIT procedure with good outcome.

Fetal MRI of cloacal exstrophy.

BACKGROUND: Prenatal ultrasonographic (US) diagnosis of cloacal exstrophy (CE) is challenging. OBJECTIVE: To define the fetal MRI findings in CE. MATERIALS AND METHODS: We performed a retrospective review of eight patients with CE. Imaging was performed between 22 weeks and 36 weeks of gestation with US in four and MRI in eight fetuses. Abdominal wall, gastrointestinal/genitourinary, and spine and limb abnormalities detected were compared with postnatal evaluation. RESULTS: US failed to display CE in one of the four fetuses. Fetal MRI confirmed CE in all eight fetuses by demonstrating absence of a normal bladder and lack of meconium-filled rectum/colon, associated with protuberant pelvic contour and omphalocele. These findings correlated postnatally with CE, atretic hindgut and omphalocele. One fetus had imaging before rupture of the cloacal membrane, showing a protruding pelvic cyst. Absent bladder was noted in the remaining seven fetuses. Confirmed skin-covered spinal defects were noted in seven fetuses, low conus/tethered cord in one and clubfoot in three. Six fetuses had renal anomalies, two had hydrocolpos and one had ambiguous genitalia. CONCLUSION: Fetal MRI provides a confident diagnosis of CE when a normal bladder is not identified, there is a protuberant abdominopelvic contour and there is absence of meconium-filled rectum and colon. Genitourinary and spinal malformations are common associations.

'Benign' ovarian teratoma and N-methyl-D-aspartate receptor (NMDAR) encephalitis in a child.

N-methyl-D-aspartate receptor (NMDAR) encephalitis is a life-threatening paraneoplastic neuropsychiatric encephalitis that predominantly affects young women and has a strong association with ovarian teratomas. Removal of the ovarian teratomas improves the prognosis and decreases the risk of recurrence. We present an 11-year-old girl with NMDAR encephalitis with small bilateral teratomas not initially appreciated on abdominal CT or pelvic MRI. A 12-mm teratoma was identified in the right ovary and a 7-mm teratoma was identified in the left ovary on US follow-up at 5 months. Intraoperative sonography was used to localize the teratomas for excision. In NMDAR encephalitis, the ovarian teratomas can be very small, particularly in children, and easily missed on cross-sectional imaging. Awareness of the association of NMDAR encephalitis and ovarian teratomas will improve the diagnostic accuracy and imaging interpretation. Periodic sonography and MRI might be warranted in children if the initial study is negative.

Prenatal imaging of amniotic band sequence: utility and role of fetal MRI as an adjunct to prenatal US.

BACKGROUND: Amniotic band sequence and its US manifestations have been well-described. There is little information, however, regarding the accuracy and utility of fetal MRI. OBJECTIVE: To describe the MRI findings in amniotic band sequence and to compare the diagnostic accuracy of MRI and US. MATERIALS AND METHODS: Prenatal MRI and US studies were retrospectively reviewed in 14 consecutive pregnancies with confirmed amniotic band sequence. Both studies were evaluated for amniotic band visualization, body part affected, type of deformity, umbilical cord involvement and vascular abnormality. RESULTS: Amniotic bands were confidently identified with MRI in 8 fetuses (57%), suggested with MRI in 3 fetuses (21%) and confidently seen by US in 13 fetuses (93%). Neither modality detected surgically proven bands on one fetus. Both techniques were equally able to define the body part affected and the type of deformity. At least one limb abnormality was visualized in all cases and truncal involvement was present in two cases. Cord involvement was identified in seven cases, with one case detected only by MRI. CONCLUSION: Fetal MRI is able to visualize amniotic bands and their secondary manifestations and could be complementary to prenatal US when fetal surgery is contemplated.

Prenatal counseling for cloaca and cloacal exstrophy-challenges faced by pediatric surgeons.

INTRODUCTION: With the advance of prenatal imaging, more often pediatric surgeons are called for prenatal counseling in suspected cases of cloaca or cloacal exstrophy. This presents new challenges for pediatric surgeons since no specific guidelines have been established so far. The purpose of this review is to analyze our experience in prenatally diagnosed cloaca or cloacal exstrophy and to provide some guidelines for prenatal counseling of these complex congenital anomalies. METHODS: A retrospective review of the medical charts of patients with prenatally diagnosed cloaca and cloacal exstrophy who received postnatal care in our institution between July 2005 and March 2012 was performed. Representative images of prenatal studies were selected from 13 cases to illustrate different scenarios and the recommendations given. In addition, a review of the literature was performed to support our advice to parents. RESULTS: Eleven patients were female and two patients were male. The postnatal diagnoses were cloacal exstrophy (6), cloaca (5), posterior cloaca variant (1), and covered cloacal exstrophy (1). The selected abnormal prenatal imaging findings in these 13 patients included hydronephrosis (12), neural tube defect (8), omphalocele (7), lack of meconium at expected rectal location (7), vertebral anomaly (7), non-visualize bladder (5), distended bladder (5), hydrocolpos (4), dilated or echogenic bowel (3), umbilical cord cyst (3), separated pubic bones (2), and the "elephant trunk" sign (2). The prenatal diagnosis was correct in 10 cases, partially correct in two cases, and it was missed in one case. All parents received prenatal counseling depending on the specific diagnosis. CONCLUSION: The continuous technologic innovations in prenatal imaging make it possible to prenatally diagnose more complex anomalies including cloaca and cloacal exstrophy with increased levels of confidence and enhance the benefit of prenatal counseling. Together, these allow the parents to be better prepared for the condition and the care team to provide the best possible initial management in order to improve the outcomes of these challenging patients.

Fetal MRI clues to diagnose cloacal malformations.

BACKGROUND: Prenatal US detection of cloacal malformations is challenging and rarely confirms this diagnosis. OBJECTIVE: To define the prenatal MRI findings in cloacal malformations. MATERIALS AND METHODS: We performed a retrospective study of patients with cloacal malformations who had pre- and post-natal assessment at our institution. Fetal MRI was obtained in six singleton pregnancies between 26 and 32 weeks of gestation. Imaging analysis was focused on the distal bowel, the urinary system and the genital tract and compared with postnatal clinical, radiological and surgical diagnoses. RESULTS: The distal bowel was dilated and did not extend below the bladder in five fetuses. They had a long common cloacal channel (3.5-6 cm) and a rectum located over the bladder base. Only one fetus with a posterior cloacal variant had a normal rectum. Three fetuses had increased T2 signal in the bowel and two increased T1/decreased T2 signal bladder content. All had renal anomalies, four had abnormal bladders and two had hydrocolpos. CONCLUSION: Assessment of the anorectal signal and pelvic anatomy during the third trimester helps to detect cloacal malformations in the fetus. The specificity for this diagnosis was highly increased when bowel fluid or bladder meconium content was identified.