Prenatal assessment of brain malformations on neuroimaging: an expert panel review.

Brain malformations represent a heterogeneous group of abnormalities of neural morphogenesis, often associated with aberrations of neuronal connectivity and brain volume. Prenatal detection of brain malformations requires a clear understanding of embryology and developmental morphology through the various stages of gestation. This expert panel review is written with the central aim of providing an easy-to-understand roadmap to improve prenatal detection and characterization of structural malformations based on the current understanding of normal and aberrant brain development. The utility of each available neuroimaging modality including prenatal multiplanar neurosonography, anatomical magnetic resonance imaging (MRI), and advanced MRI techniques, as well as further insights from post-mortem imaging have been highlighted for every developmental stage.

Longitudinal analysis of regional brain changes in anti-NMDAR encephalitis: a case report.

BACKGROUND: Anti-NMDA receptor encephalitis is an immune-mediated disorder characterized by antibodies against the GluN1 subunit of the NMDA receptor that is increasingly recognized as a treatable cause of childhood epileptic encephalopathy. In adults, the disorder has been associated with reversible changes in brain volume over the course of treatment and recovery, but in children, little is known about its time course and associated imaging manifestations. CASE PRESENTATION: A previously healthy 20-month-old boy presented with first-time unprovoked seizures, dysautonomia, and dyskinesia. Paraneoplastic workup was negative, but CSF was positive for anti-NMDAR antibodies. The patient's clinical condition waxed and waned over a 14-month course of treatment with first- and second-line immunotherapies (including steroids, IVIG, rituximab, and cyclophosphamide). Serial brain MRIs scans obtained at 5 time points spanning this same period showed no abnormal signal or enhancement but were remarkable for cycles of reversible regional cortical volume loss. All scans included identical 1-mm resolution 3D T1-weighted sequences obtained on the same 3 T scanner. Using a novel longitudinal processing stream in FreeSurfer6 (Reuter M, et. al, Neuroimage 61:1402-18, 2012) we quantified the rate of change in cortical volume at each vertex (% volume change per month) between consecutive scans and correlated these changes with the time course of the patient's treatment and clinical response. We found regionally specific changes in cortical volume (up to 7% per month) that preferentially affected the frontal and occipital lobes and paralleled the patient's clinical course, with clinical decline associated with volume loss and clinical improvement associated with volume gain. CONCLUSIONS: Our results suggest that reversible cortical volume loss in anti-NMDA encephalitis has a regional specificity that mirrors many of the clinical symptoms associated with the disorder and tracks the dynamics of disease severity over time. This case illustrates how quantitative morphometric techniques can be applied to clinical imaging data to reveal patterns of brain change that may provide insight into disease pathophysiology. More widespread application of this approach might reveal regional and temporal patterns specific to different types of autoimmune encephalitis, providing a tool for diagnosis and a surrogate marker for monitoring treatment response.

Definitions and classification of malformations of cortical development: practical guidelines.

Malformations of cortical development are a group of rare disorders commonly manifesting with developmental delay, cerebral palsy or seizures. The neurological outcome is extremely variable depending on the type, extent and severity of the malformation and the involved genetic pathways of brain development. Neuroimaging plays an essential role in the diagnosis of these malformations, but several issues regarding malformations of cortical development definitions and classification remain unclear. The purpose of this consensus statement is to provide standardized malformations of cortical development terminology and classification for neuroradiological pattern interpretation. A committee of international experts in paediatric neuroradiology prepared systematic literature reviews and formulated neuroimaging recommendations in collaboration with geneticists, paediatric neurologists and pathologists during consensus meetings in the context of the European Network Neuro-MIG initiative on Brain Malformations (https://www.neuro-mig.org/). Malformations of cortical development neuroimaging features and practical recommendations are provided to aid both expert and non-expert radiologists and neurologists who may encounter patients with malformations of cortical development in their practice, with the aim of improving malformations of cortical development diagnosis and imaging interpretation worldwide.

Novel KIF7 missense substitutions in two patients presenting with multiple malformations and features of acrocallosal syndrome.

We present two children who both had two missense mutations in the Kinesin Family Member 7 (KIF7) gene. A seven year old female with severe developmental delays, failure to thrive and growth retardation, infantile spasms, a cardiac vascular ring and right-sided aortic arch, imperforate anus, hydronephrosis with a right renal cyst, syndactyly and abnormal white matter was a compound heterozygote for c.3365C > G, predicting p.(Ser1122Trp) that was maternally inherited and c.2482G > A, predicting p.(Val828Met) that was paternally inherited. An eight year old female with severe developmental delays, epilepsy, left postaxial polydactyly of the hand and abnormalities of brain development including hydrocephalus, pachygyria and absence of the body and splenium of the corpus callous was a compound heterozygote for c.461G > A, predicting p.(Arg154Gln) and c.2959 G > A, predicting p.(Glu987Lys) that was maternally inherited and her father was unavailable for testing. The presentations in these children include features of acrocallosal syndrome, such as hypoplasia of the corpus callosum, enlarged ventricles, facial dysmorphism with a prominent forehead and broad halluces in the first child, but included atypical findings for individuals previously reported to have truncating mutations in KIF7, including imperforate anus, infantile spasms and severe growth retardation. We conclude that these phenotypes may result from the KIF7 sequence variants and abnormal hedgehog signaling, but that the full spectrum of KIF7-associated features remains to be determined.

Developmental progress and creatine restoration upon long-term creatine supplementation of a patient with arginine:glycine amidinotransferase deficiency.

BACKGROUND: Arginine:glycineamidinotransferase (AGAT/GATM) deficiency has been described in 9 patients across 4 families. Here we describe the clinical outcome and response to creatine supplementation in a patient of the second family affected with AGAT deficiency-a 9-year-old girl. PATIENT AND METHODS: Delayed motor milestones were noticed from 4 months of age and at 14 months moderate hypotonia, developmental delay and failure to thrive. Laboratory studies revealed low plasma creatine as well as extremely low levels of guanidinoacetic acid in urine and plasma. Proton magnetic resonance spectroscopy (MRS) of the brain showed absence of creatine. DNA sequence analysis revealed a homozygous mutation (c.484+1G>T) in the AGAT/GATM gene. AGAT activity was not detectable in lymphoblasts and RNA analysis revealed a truncated mRNA (r.289_484del196) that is degraded via Nonsense Mediated Decay. At 16 months, Bayley's Infant Development Scale (BIDS) showed functioning at 43% of chronologic age. Oral creatine supplementation (up to 800 mg/kg/day) was begun. RESULTS: At age 9 years she demonstrated advanced academic performance. Partial recovery of cerebral creatine levels was demonstrated on MRS at 25 months of age. Brain MRS at 40 months of age revealed a creatine/NAA ratio of about 80% of that in age-matched controls. CONCLUSIONS: 8 years post initiation of oral creatine supplementation, patient demonstrates superior nonverbal and academic abilities, with average verbal skills. We emphasize that early diagnosis combined with early treatment onset of AGAT deficiency may lead to improvement of developmental outcome.

Registration-based approach for reconstruction of high-resolution in utero fetal MR brain images.

RATIONALE AND OBJECTIVES: This paper describes a novel approach to forming high-resolution MR images of the human fetal brain. It addresses the key problem of fetal motion by proposing a registration-refined compounding of multiple sets of orthogonal fast two-dimensional MRI slices, which are currently acquired for clinical studies, into a single high-resolution MRI volume. MATERIALS AND METHODS: A robust multiresolution slice alignment is applied iteratively to the data to correct motion of the fetus that occurs between two-dimensional acquisitions. This is combined with an intensity correction step and a super-resolution reconstruction step, to form a single high isotropic resolution volume of the fetal brain. RESULTS: Experimental validation on synthetic image data with known motion types and underlying anatomy, together with retrospective application to sets of clinical acquisitions, are included. CONCLUSION: Results indicate that this method promises a unique route to acquiring high-resolution MRI of the fetal brain in vivo allowing comparable quality to that of neonatal MRI. Such data provide a highly valuable window into the process of normal and abnormal brain development, which is directly applicable in a clinical setting.

Symptomatic epidural lipomatosis of the spinal cord in a child: MR demonstration of spinal cord injury.

We report a case of symptomatic epidural lipomatosis in an 8-year-old girl with Cushing's syndrome secondary to longstanding high-dose steroid therapy for Crohn's disease. MR imaging of the spine revealed massive diffuse epidural fat compressing the entire spinal cord with T2 prolongation in the central gray matter of the cord suggesting ischemic myelopathy. This finding has not been previously demonstrated on imaging. A proposed mechanism underlying these findings is discussed.