Fetal magnetic resonance imaging, ultrasound, and echocardiography findings in twin reversed arterial perfusion sequence.

BACKGROUND: Twin reversed arterial perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation pregnancies, in which the pump twin provides hemodynamic support to a nonviable co-twin (acardius). Fetal magnetic resonance imaging (MRI) is used to detect pump twin abnormalities, particularly brain ischemia, prior to fetal intervention to interrupt umbilical blood flow to the acardius. OBJECTIVE: To summarize the imaging findings of TRAP sequence pregnancies in a large series. MATERIALS AND METHODS: A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected. RESULTS: Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardius to pump twin ratio A/P ratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson's r=0.45 and 0.48, respectively, both P<.001). CONCLUSION: Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.

Association of enlarged extra-axial spaces and subdural hemorrhage in preterm infants at term-equivalent age.

To determine the incidence of enlarged extra-axial space (EES) and its association with subdural hemorrhage (SDH) in a regional cohort of preterm infants. As part of a prospective cohort study of 395 preterm infants, brain magnetic resonance imaging (MRI) was collected on each infant at term-equivalent age. Six preterm infants showed evidence of SDH. We reviewed the MRIs to identify the incidence of EES in these 6 infants and the cohort broadly. We then completed a retrospective chart review of the 6 infants to identify any concerns for non-accidental trauma (NAT) since the MRI was obtained. The incidence of SDH in the cohort was 1.6%. The incidence of EES was 48.1% including all 6 infants with SDH. The incidence of SDH in infants with EES was 3.2%. The retrospective chart review of the 6 infants did not yield any evidence of NAT. The incidence of EES and SDH in our cohort was significantly higher than similar cohorts of term infants, demonstrating an increased risk in preterm infants. The incidence of SDH in infants with EES was greater than in the total cohort, suggesting that it is a risk factor for asymptomatic SDH in preterm infants.

Further expansion and confirmation of phenotype in rare loss of YWHAE gene distinct from Miller-Dieker syndrome.

Deletion of 17p13.3 has varying degrees of severity on brain development based on precise location and size of the deletion. The most severe phenotype is Miller-Dieker syndrome (MDS) which is characterized by lissencephaly, dysmorphic facial features, growth failure, developmental disability, and often early death. Haploinsufficiency of PAFAH1B1 is responsible for the characteristic lissencephaly in MDS. The precise role of YWHAE haploinsufficiency in MDS is unclear. Case reports are beginning to elucidate the phenotypes of individuals with 17p13.3 deletions that have deletion of YWHAE but do not include deletion of PAFAH1B1. Through our clinical genetics practice, we identified four individuals with 17p13.3 deletion that include YWHAE but not PAFAH1B1. These patients have a similar phenotype of dysmorphic facial features, developmental delay, and leukoencephalopathy. In a review of the literature, we identified 19 patients with 17p13.3 microdeletion sparing PAFAH1B1 but deleting YWHAE. Haploinsufficiency of YWHAE is associated with brain abnormalities including cystic changes. These individuals have high frequency of epilepsy, intellectual disability, and dysmorphic facial features including prominent forehead, epicanthal folds, and broad nasal root. We conclude that deletion of 17p13.3 excluding PAFAH1B1 but including YWHAE is associated with a consistent phenotype and should be considered a distinct condition from MDS.

MRI Findings in Third-Trimester Opioid-Exposed Fetuses, With Focus on Brain Measurements: A Prospective Multicenter Case-Control Study.

BACKGROUND. The opioid epidemic has profoundly affected infants born in the United States, as in utero opioid exposure increases the risk of cognitive and behavioral problems in childhood. Scarce literature has evaluated prenatal brain development in fetuses with opioid exposure in utero (hereafter opioid-exposed fetuses). OBJECTIVE. The purpose of this study is to compare opioid-exposed fetuses and fetuses without opioid exposure (hereafter unexposed fetuses) in terms of 2D biometric measurements of the brain and additional pregnancy-related assessments on fetal MRI. METHODS. This prospective case-control study included patients in the third trimester of pregnancy who underwent investigational fetal MRI at one of three U.S. academic medical centers from July 1, 2020, through December 31, 2021. Fetuses were classified as opioid exposed or unexposed in utero. Fourteen 2D biometric measurements of the fetal brain were manually assessed and used to derive four indexes. Measurements and indexes were compared between the two groups by use of multivariable linear regression models, which were adjusted for gestational age (GA), fetal sex, and nicotine exposure. Additional pregnancy-related findings on MRI were evaluated. RESULTS. The study included 65 women (mean age, 29.0 ± 5.5 [SD] years). A total of 28 fetuses (mean GA at the time of MRI, 32.2 ± 2.5 weeks) were opioid-exposed, and 37 fetuses (mean GA at the time of MRI, 31.9 ± 2.7 weeks) were unexposed. In the adjusted models, seven measurements were smaller (p < .05) in opioid-exposed fetuses than in unexposed fetuses: cerebral frontooccipital diameter (93.8 ± 7.4 vs 95.0 ± 8.6 mm), bone biparietal diameter (79.0 ± 6.0 vs 80.3 ± 7.1 mm), brain biparietal diameter (72.9 ± 7.7 vs 74.1 ± 8.6 mm), corpus callosum length (37.7 ± 4.0 vs 39.4 ± 3.7 mm), vermis height (18.2 ± 2.7 vs 18.8 ± 2.6 mm), anteroposterior pons measurement (11.6 ± 1.4 vs 12.1 ± 1.4 mm), and transverse cerebellar diameter (40.4 ± 5.1 vs 41.4 ± 6.0 mm). In addition, in the adjusted model, the frontoocccipital index was larger (p = .02) in opioid-exposed fetuses (0.04 ± 0.02) than in unexposed fetuses (0.04 ± 0.02). Remaining measures and indexes were not significantly different between the two groups (p > .05). Fetal motion, cervical length, and deepest vertical pocket of amniotic fluid were not significantly different (p > .05) between groups. Opioid-exposed fetuses, compared with unexposed fetuses, showed higher frequencies of both breech position (21% vs 3%, p = .03) and increased amniotic fluid volume (29% vs 8%, p = .04). CONCLUSION. Fetuses with opioid exposure in utero had a smaller brain size and altered fetal physiology. CLINICAL IMPACT. The findings provide insight into the impact of prenatal opioid exposure on fetal brain development.

Acute histologic chorioamnionitis independently and directly increases the risk for brain abnormalities seen on magnetic resonance imaging in very preterm infants.

BACKGROUND: The independent risk for neurodevelopmental impairments attributed to chorioamnionitis in premature infants remains controversial. Delayed brain maturation or injury identified on magnetic resonance imaging at term-equivalent age can be used as a surrogate measure of neurodevelopmental impairments that is less confounded by postdelivery neonatal intensive care unit environmental factors to investigate this relationship more clearly. OBJECTIVE: This study aimed to determine whether preterm infants born with moderate to severe acute histologic chorioamnionitis would have a higher magnetic resonance imaging-determined global brain abnormality score, independent of early premature birth, when compared with preterm infants with no or mild chorioamnionitis. STUDY DESIGN: This was a prospective, multicenter cohort study involving infants born very prematurely ≤32 weeks' gestational age with acute moderate to severe histologic chorioamnionitis, graded using standard histologic criteria. Brain abnormalities were diagnosed and scored using a well-characterized, standardized scoring system captured using a high-resolution 3 Tesla magnetic resonance imaging research magnet. In secondary analyses, total brain volume and 4 magnetic resonance imaging metrics of cortical maturation (cortical surface area, sulcal depth, gyral index, and inner cortical curvature) were calculated using an automated algorithm and correlated with chorioamnionitis. The association of funisitis (any grade) with brain abnormalities was also explored. We investigated if premature birth mediated the relationship between histologic chorioamnionitis and brain abnormality score using mediation analysis. RESULTS: Of 353 very preterm infants, 297 infants had mild or no chorioamnionitis (controls), and 56 were diagnosed with moderate to severe acute histologic chorioamnionitis. The primary outcome brain abnormality score was significantly higher in histologic chorioamnionitis-exposed infants than in the controls (median, 4 vs 7; P<.001). Infants with acute histologic chorioamnionitis had significantly lower brain tissue volume (P=.03) and sulcal depth (P=.04), whereas other morphometric indices did not differ statistically. In the multiple regression analysis, we observed persistent significant relationships between moderate to severe acute histologic chorioamnionitis and brain abnormality scores (ß=2.84; 1.51-4.16; P<.001), total brain volume (P=.03), and sulcal depth (P=.02). Funisitis was also significantly associated with brain abnormality score after adjustment for clinical confounders (P=.005). Mediation analyses demonstrated that 50% of brain abnormalities was an indirect consequence of premature birth, and the remaining 50% was a direct effect of moderate to severe acute histologic chorioamnionitis when compared with preterm infants with no or mild chorioamnionitis exposure. Examining gestational age as a mediator, funisitis did not exert a significant direct effect on brain abnormalities after the significant indirect effects of preterm birth were accounted for. CONCLUSION: Acute histologic chorioamnionitis increases the risk for brain injury and delayed maturation, both directly and indirectly, by inducing premature birth.

Value of pre- and postnatal magnetic resonance imaging in the evaluation of congenital central nervous system anomalies.

Fetal MRI and neonatal MRI of the central nervous system (CNS) are complementary tools that can help to accurately counsel and direct the management of children with anomalies of the central nervous system. Postnatal MRI can add to fetal MRI by allowing for monitoring of changes in the severity of disease, better delineation of a suspected prenatal anomaly, evaluation for secondary pathologies related to the primary diagnosis, and surgical management direction. In this review we discuss the roles of fetal and neonatal MRI in the diagnosis and treatment of congenital anomalies of the CNS through a series of case examples and how both are important in patient management.

Prenatal opioid exposure is associated with smaller brain volumes in multiple regions.

BACKGROUND: The impact of prenatal opioid exposure on brain development remains poorly understood. METHODS: We conducted a prospective study of term-born infants with and without prenatal opioid exposure. Structural brain MRI was performed between 40 and 48 weeks postmenstrual age. T2-weighted images were processed using the Developing Human Connectome Project structural pipeline. We compared 63 relative regional brain volumes between groups. RESULTS: Twenty-nine infants with prenatal opioid exposure and 42 unexposed controls were included. The groups had similar demographics, except exposed infants had lower birth weights, more maternal smoking and maternal Hepatitis C, fewer mothers with a college degree, and were more likely non-Hispanic White. After controlling for sex, postmenstrual age at scan, birth weight, and maternal education, exposed infants had significantly smaller relative volumes of the deep gray matter, bilateral thalamic ventrolateral nuclei, bilateral insular white matter, bilateral subthalamic nuclei, brainstem, and cerebrospinal fluid. Exposed infants had larger relative volumes of the right cingulate gyrus white matter and left occipital lobe white matter. CONCLUSIONS: Infants with prenatal opioid exposure had smaller brain volumes in multiple regions compared to controls, with two regions larger in the opioid-exposed group. Further research should focus on the relative contributions of maternal opioids and other exposures. IMPACT: Prenatal opioid exposure is associated with developmental and behavioral consequences, but the direct effects of opioids on the developing human brain are poorly understood. Prior small studies using MRI have shown smaller regional brain volumes in opioid-exposed infants and children. After controlling for covariates, infants with prenatal opioid exposure scanned at 40-48 weeks postmenstrual age had smaller brain volumes in multiple regions compared to controls, with two regions larger in the opioid-exposed group. This adds to the literature showing potential impact of prenatal opioid exposure on the developing brain.

Pediatric hanging and strangulation: is vascular injury a true risk?

BACKGROUND: Acute screening of pediatric strangulation and hanging injuries has evolved at many institutions to include cervical arterial vascular imaging. As current standards in pediatric imaging support less radiation exposure and increased imaging appropriateness, it is questionable whether vascular arterial injury is a true risk in this population. OBJECTIVE: To determine the role of cervical vascular arterial imaging in the evaluation of pediatric hanging and strangulation injuries. MATERIALS AND METHODS: This is a retrospective study of patients who present at a Level 1 pediatric trauma center with a history of hanging and strangulation injuries. All relevant studies, including computed tomography (CT) angiography of the neck, contrast-enhanced neck CT, cervical magnetic resonance (MR) angiography, magnetic resonance imaging (MRI) and/or CT of the brain and cervical spine and associated clinical records, were reviewed. RESULTS: Sixty-six patients were identified, 60 with vascular arterial imaging studies. No vascular injury was identified. Soft-tissue injury was noted in 20/66 (30%) patients and craniocervical injury was suspected in 2/66 (3%), but no cervical spine fracture was identified. Only 49 patients had brain imaging, with 7/49 (14%) demonstrating changes consistent with cerebral edema, which correlated negatively with survival (P<0.01). CONCLUSION: Vascular arterial imaging, particularly with CT angiography, performed in the pediatric population after hanging and strangulation injury resulted in no positive studies for cervical arterial injury. This study supports the need to reevaluate routine screening CT angiography in this study population.

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.

Prenatal and postnatal MRI findings in open spinal dysraphism following intrauterine repair via open versus fetoscopic surgical techniques.

PURPOSE: The purpose of the study is to examine MRI findings of the brain and spine on prenatal and postnatal MRI following intrauterine repair of open spinal dysraphism (OSD) by open hysterotomy and fetoscopic approaches. MATERIALS AND METHODS: This study is a single-center HIPAA-compliant and IRB-approved retrospective analysis of fetal MRIs with open spinal dysraphism from January 2011 through December 2018 that underwent subsequent prenatal repair of OSD. RESULTS: Sixty-two patients met inclusion criteria: 47 underwent open repair, and 15 underwent fetoscopic repair, with an average gestational age of 22.6 ± 1.4 weeks at initial MRI. On postnatal MRI, spinal cord syrinx was seen in 34% (16/47) of patients undergoing open versus 33.3% (5/15) undergoing fetoscopic repair (P = 0.96). Postnatally, there was no significant difference in hindbrain herniation between the open versus fetoscopic repair groups (P = 0.28). Lateral ventricular size was significantly larger in the open (20.9 ± 6.7 mm) versus the fetoscopic repair (16.1 ± 4.9 mm) group (P = 0.01). CONCLUSION: Though lateral ventricular size in the open repair group was larger than the fetoscopic repair group, this can likely be explained by initial selection criteria used for fetoscopic repair. Other postoperative imaging parameters on postnatal MRI were not significantly different between the two groups.

Imaging diagnosis of ventriculomegaly: fetal, neonatal, and pediatric.

Ventriculomegaly is the term used to describe abnormal enlargement of ventricles in the brain. Neuroimaging, whether it is by ultrasound, computed tomography, or magnetic resonance imaging, is the key to its identification and can help to diagnose its cause and guide management in many cases. The implementation of the imaging modalities and potential differential considerations varies from the fetus, infant, and pediatric patient. Here we discuss how the imaging modalities can be used in these patient populations and review some of the differential considerations.

Imaging of open spinal dysraphisms in the era of prenatal surgery.

Over the last decade fetal surgery to repair open spinal dysraphisms has become an acceptable and in some cases desirable alternative to the traditional method of postnatal closure. Fetal MRI is an essential part of the workup in these patients, not only to select the appropriate candidates for fetal surgery but also to guide prenatal counseling and perinatal management. In this article we review current surgical techniques for prenatal repair, relevant imaging findings in the era of fetal surgery, and expected imaging findings of the brain and spine in the fetal and postnatal periods.

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.

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.

Neonatal Functional and Structural Connectivity Are Associated with Cerebral Palsy at Two Years of Age.

OBJECTIVE: The accuracy of structural magnetic resonance imaging (MRI) to predict later cerebral palsy (CP) in newborns with perinatal brain injury is variable. Diffusion tensor imaging (DTI) and task-based functional MRI (fMRI) show promise as predictive tools. We hypothesized that infants who later developed CP would have reduced structural and functional connectivity as compared with those without CP. STUDY DESIGN: We performed DTI and fMRI using a passive motor task at 40 to 48 weeks' postmenstrual age in 12 infants with perinatal brain injury. CP was diagnosed at age 2 using a standardized examination. RESULTS: Five infants had CP at 2 years of age, and seven did not have CP. Tract-based spatial statistics showed a widespread reduction of fractional anisotropy (FA) in almost all white matter tracts in the CP group. Using the median FA value in the corticospinal tracts as a cutoff, FA was 100% sensitive and 86% specific to predict CP compared with a sensitivity of 60 to 80% and a specificity of 71% for structural MRI. During fMRI, the CP group had reduced functional connectivity from the right supplemental motor area as compared with the non-CP group. CONCLUSION: DTI and fMRI obtained soon after birth are potential biomarkers to predict CP in newborns with perinatal brain injury.

Prenatal evaluation of the Sakoda complex.

Sakoda complex is a rare but distinct combination of birth defects consisting of a basal cephalocele, agenesis of the corpus callosum, and midline cleft lip/palate. It has been reported in association with ophthalmologic abnormalities, cognitive deficits and severe epilepsy. Here we describe both prenatal and postnatal MRI findings of a classic case of Sakoda complex in a child with characteristic findings on fetal MRI; prenatal findings have not been described in the literature. Diagnosis of this entity has important implications for prenatal counseling and perinatal management, as is demonstrated in this case.

Fetal brain morphometry on prenatal magnetic resonance imaging in congenital diaphragmatic hernia.

BACKGROUND: Many infants with congenital diaphragmatic hernia (CDH) show brain abnormality on postnatal brain MRI related to severity of CDH, degree of lung hypoplasia, intrathoracic liver, right diaphragmatic hernia and large diaphragmatic defect. It is not known whether these factors affect brain growth in utero in CDH. OBJECTIVE: To assess prenatal brain morphometry and abnormalities on fetal MR in congenital diaphragmatic hernia. MATERIALS AND METHODS: We retrospectively reviewed 109 fetal MRIs in 63 fetuses with CDH from 2009 to 2014 (27 died before discharge, 36 survived to discharge). We compared brain injury and gestational-age-corrected z-scores of brain measurements between survivors and non-survivors. We assessed correlations between brain abnormalities and CDH severity. RESULTS: Enlarged extraaxial space was the most common abnormality, frequently seen on fetal MRI at >28 weeks of gestation, similar in survivors versus non-survivors. Anteroposterior cerebellar vermis dimension at >28 weeks of gestation was smaller in non-survivors compared to survivors (P=.02) and positively correlated with observed/expected total fetal lung volume (P=.01). Transverse cerebellar diameter at >28 weeks of gestation was also positively correlated with observed/expected total fetal lung volume (P=.04). We did not identify maturational delay, abnormal parenchymal signal or intracranial hemorrhage on fetal MRI. CONCLUSION: Enlarged extraaxial spaces in the third trimester was the most common abnormality on fetal MRI in congenital diaphragmatic hernia. Cerebellar dimensions on fetal MRI are associated with CDH severity. There was no major brain parenchymal injury on fetal MRI, even in the third trimester, in CDH survivors and non-survivors.

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.