T2-FLAIR Mismatch: An Imaging Biomarker for Children's MYB/MYBL1-Altered Diffuse Astrocytoma or Angiocentric Glioma.

BACKGROUND AND PURPOSE: T2-FLAIR mismatch is a highly specific imaging biomarker of IDH-mutant diffuse astrocytoma in adults. It has however also been described in MYB/MYBL1-altered low grade tumors. Our aim was to assess the diagnostic power of the T2-FLAIR mismatch in IDH-mutant astrocytoma and MYB/MYBL1-altered low-grade tumors in children and correlate this mismatch with histology. MATERIALS AND METHODS: We evaluated MR imaging examinations of all pediatric patients, performed at the Princess Máxima Center for Pediatric Oncology and the University Medical Center Utrecht between January 2012 and January 2023, with the histomolecular diagnosis of IDH-mutant astrocytoma, diffuse astrocytoma MYB/MYBL1-altered, or angiocentric glioma, and the presence of T2-FLAIR mismatch was assessed. Histologically, the presence of microcysts in the tumor (a phenomenon suggested to be correlated with T2-FLAIR mismatch in IDH-mutant astrocytomas in adults) was evaluated. RESULTS: Nineteen pediatric patients were diagnosed with either IDH-mutant astrocytoma (n = 8) or MYB/MYBL1-altered tumor (n = 11: diffuse astrocytoma, MYB- or MYBL1-altered n = 8; or angiocentric glioma n = 3). T2-FLAIR mismatch was present in 11 patients, 3 (38%) in the IDH-mutant group and 8 (73%) in the MYB/MYBL1 group. No correlation was found between T2-FLAIR mismatch and the presence of microcysts or an enlarged intercellular space in either IDH-mutant astrocytoma (P = .38 and P = .56, respectively) or MYB/MYBL1-altered tumors (P = .36 and P = .90, respectively). CONCLUSIONS: In our pediatric population, T2-FLAIR mismatch was more often found in MYB/MYBL1-altered tumors than in IDH-mutant astrocytomas. In contrast to what has been reported for IDH-mutant astrocytomas in adults, no correlation was found with microcystic changes in the tumor tissue. This finding challenges the hypothesis that such microcystic changes and/or enlarged intercellular spaces in the tissue of these tumors are an important part of explaining the occurrence of the T2-FLAIR mismatch.

The long-term outcome of revision microdiscectomy for recurrent sciatica.

PURPOSE: To study the long-term outcome of revision microdiscectomy after classic microdiscectomy for lumbosacral radicular syndrome (LSRS). METHODS: Eighty-eight of 216 patients (41%) who underwent a revision microdiscectomy between 2007 and 2010 for MRI disc-related LSRS participated in this study. Questionnaires included visual analogue scores (VAS) for leg pain, RDQ, OLBD, RAND-36, and seven-point Likert scores for recovery, leg pain, and back pain. Any further lumbar re-revision operation(s) were recorded. RESULTS: Mean (SD) age was 59.8 (12.8), and median [IQR] time of follow-up was 10.0 years [9.0-11.0]. A favourable general perceived recovery was reported by 35 patients (40%). A favourable outcome with respect to perceived leg pain was present in 39 patients (45%), and 35 patients (41%) reported a favourable outcome concerning back pain. The median VAS for leg and back pain was worse in the unfavourable group (48.0/100 mm (IQR 16.0-71.0) vs. 3.0/100 mm (IQR 2.0-5.0) and 56.0/100 mm (IQR 27.0-74.0) vs. 4.0/100 mm (IQR 2.0-17.0), respectively; both p < 0.001). Re-revision operation occurred in 31 (35%) patients (24% same level same side); there was no significant difference in the rate of favourable outcome between patients with or without a re-revision operation. CONCLUSION: The long-term results after revision microdiscectomy for LSRS show an unfavourable outcome in the majority of patients and a high risk of re-revision microdiscectomy, with similar results. Based on also the disappointing results of alternative treatments, revision microdiscectomy for recurrent LSRS seems to still be a valid treatment. The results of our study may be useful to counsel patients in making appropriate treatment choices.

Medullary Tegmental Cap Dysplasia: Fetal and Postnatal Presentations of a Unique Brainstem Malformation.

BACKGROUND AND PURPOSE: Medullary tegmental cap dysplasia is a rare brainstem malformation, first described and defined by James Barkovich in his book Pediatric Neuroimaging from 2005 as an anomalous mass protruding from the posterior medullary surface. We describe the neuroimaging, clinical, postmortem, and genetic findings defining this unique malformation. MATERIALS AND METHODS: This is a multicenter, international, retrospective study. We assessed the patients' medical records, prenatal ultrasounds, MR images, genetic findings, and postmortem results. We reviewed the medical literature for all studies depicting medullary malformations and evaluated cases in which a dorsal medullary protuberance was described. RESULTS: We collected 13 patients: 3 fetuses and 10 children. The medullary caps had multiple characteristics. Associated brain findings were a rotated position of the medulla, a small and flat pons, cerebellar anomalies, a molar tooth sign, and agenesis of the corpus callosum. Systemic findings included the following: polydactyly, hallux valgus, large ears, and coarse facies. Postmortem analysis in 3 patients revealed that the cap contained either neurons or white matter tracts. We found 8 publications describing a dorsal medullary protuberance in 27 patients. The syndromic diagnosis was Joubert-Boltshauser syndrome in 11 and fibrodysplasia ossificans progressiva in 14 patients. CONCLUSIONS: This is the first study to describe a series of 13 patients with medullary tegmental cap dysplasia. The cap has different shapes: distinct in Joubert-Boltshauser syndrome and fibrodysplasia ossificans progressive. Due to the variations in the clinical, imaging, and postmortem findings, we conclude that there are multiple etiologies and pathophysiology. We suggest that in some patients, the pathophysiology might be abnormal axonal guidance.

Introduction of ultra-high-field MR brain imaging in infants: vital parameters, temperature and comfort.

Background: Brain MRI in infants at ultra-high-field scanners might improve diagnostic quality, but safety should be evaluated first. In our previous study, we reported simulated specific absorption rates and acoustic noise data at 7 Tesla. Methods: In this study, we included twenty infants between term-equivalent age and three months of age. The infants were scanned on a 7 Tesla MRI directly after their clinically indicated 3 Tesla brain MRI scan. Vital parameters, temperature, and comfort were monitored throughout the process. Brain temperature was estimated during the MRI scans using proton MR spectroscopy. Results: We found no significant differences in vital parameters, temperature, and comfort during and after 7 Tesla MRI scans, compared to 3 Tesla MRI scans. Conclusions: These data confirm our hypothesis that scanning infants at 7 Tesla MRI appears to be safe and we identified no additional risks from scanning at 3 Tesla MRI.

Imaging Characteristics of CNS Neuroblastoma-FOXR2: A Retrospective and Multi-Institutional Description of 25 Cases.

BACKGROUND AND PURPOSE: The 5th edition of the World Health Organization Classification of CNS tumors defines the CNS neuroblastoma FOXR2 in the group of embryonal tumors. Published clinical outcomes tend to suggest a favorable outcome after resection, craniospinal irradiation, and chemotherapy. This multicenter study aimed to describe imaging features of CNS neuroblastoma-FOXR2, which have been poorly characterized thus far. MATERIALS AND METHODS: On the basis of a previously published cohort of tumors molecularly classified as CNS neuroblastoma-FOXR2, patients with available imaging data were identified. The imaging features on preoperative MR imaging and CT data were recorded by 8 experienced pediatric neuroradiologists in consensus review meetings. RESULTS: Twenty-five patients were evaluated (13 girls; median age, 4.5 years). The tumors were often large (mean, 115 [ SD, 83] mL), showed no (24%) or limited (60%) perilesional edema, demonstrated heterogeneous enhancement, were often calcified and/or hemorrhagic (52%), were always T2WI-hyperintense to GM, and commonly had cystic and/or necrotic components (96%). The mean ADC values were low (687.8 [SD 136.3] × 10-6 mm2/s). The tumors were always supratentorial. Metastases were infrequent (20%) and, when present, were of nodular appearance and leptomeningeal. CONCLUSIONS: In our cohort, CNS neuroblastoma FOXR2 tumors showed imaging features suggesting high-grade malignancy and, at the same time, showed characteristics of less aggressive behavior. There are important differential diagnoses, but the results of this study may assist in considering this diagnosis preoperatively.

Resting energy expenditure in children at risk of hypothalamic dysfunction.

Objective: Children with suprasellar brain damage are at risk of hypothalamic dysfunction (HD). HD may lead to decreased resting energy expenditure (REE). Decreased REE, however, is not present in all children with HD. Our aim was to assess which children suspect for HD have low REE, and its association with clinical severity of HD or radiological hypothalamic damage. Patients and methods: A retrospective cohort study was performed. Measured REE (mREE) of children at risk of HD was compared to predicted REE (pREE). Low REE was defined as mREE <90% of predicted. The mREE/pREE quotient was associated to a clinical score for HD symptoms and to radiological hypothalamic damage. Results: In total, 67 children at risk of HD (96% brain tumor diagnosis) with a mean BMI SDS of +2.3 ± 1.0 were included. Of these, 45 (67.2%) had low mREE. Children with severe HD had a significant lower mean mREE/pREE quotient compared to children with no, mild, or moderate HD. Mean mREE/pREE quotient of children with posterior hypothalamic damage was significantly lower compared to children with no or anterior damage. Tumor progression or tumor recurrence, severe clinical HD, and panhypopituitarism with diabetes insipidus (DI) were significant risk factors for reduced REE. Conclusion: REE may be lowered in children with hypothalamic damage and is associated to the degree of clinical HD. REE is, however, not lowered in all children suspect for HD. For children with mild or moderate clinical HD symptoms, REE measurements may be useful to distinguish between those who may benefit from obesity treatment that increases REE from those who would be better helped using other obesity interventions.

A diffusion tensor imaging analysis of white matter microstructures in non-operated craniosynostosis patients.

PURPOSE: In 7 to 15-year-old operated syndromic craniosynostosis patients, we have shown the presence of microstructural anomalies in brain white matter by using DTI. To learn more about the cause of these anomalies, the aim of the study is to determine diffusivity values in white matter tracts in non-operated syndromic craniosynostosis patients aged 0-2 years compared to healthy controls. METHODS: DTI datasets of 51 non-operated patients with syndromic craniosynostosis with a median [IQR] age of 0.40 [0.25] years were compared with 17 control subjects with a median of 1.20 [0.85] years. Major white matter tract pathways were reconstructed with ExploreDTI from MRI brain datasets acquired on a 1.5 T MRI system. Eigenvalues of these tract data were examined, with subsequent assessment of the affected tracts. Having syndromic craniosynostosis (versus control), gender, age, frontal occipital horn ratio (FOHR), and tract volume were treated as independent variables. RESULTS: ʎ2 and ʎ3 of the tracts genu of the corpus callosum and the hippocampal segment of the cingulum bundle show a ƞ2 > 0.14 in the comparison of patients vs controls, which indicates a large effect on radial diffusivity. Subsequent linear regressions on radial diffusivity of these tracts show that age and FOHR are significantly associated interacting factors on radial diffusivity (p < 0.025). CONCLUSION: Syndromic craniosynostosis shows not to be a significant factor influencing the major white matter tracts. Enlargement of the ventricles show to be a significant factor on radial diffusivity in the tracts corpus callosum genu and the hippocampal segment of the cingulate bundle. CLINICAL TRIAL REGISTRATION: MEC-2014-461.

The Mammillary Bodies: A Review of Causes of Injury in Infants and Children.

Despite their small size, the mammillary bodies play an important role in supporting recollective memory. However, they have typically been overlooked when assessing neurologic conditions that present with memory impairment. While there is increasing evidence of mammillary body involvement in a wide range of neurologic disorders in adults, very little attention has been given to infants and children. Literature searches of PubMed and EMBASE were performed to identify articles that describe mammillary body pathology on brain MR imaging in children. Mammillary body pathology is present in the pediatric population in several conditions, indicated by signal change and/or atrophy on MR imaging. The main causes of mammillary body pathology are thiamine deficiency, hypoxia-ischemia, direct damage due to masses or hydrocephalus, or deafferentation resulting from pathology within the wider Papez circuit. Optimizing scanning protocols and assessing mammillary body status as a standard procedure are critical, given their role in memory processes.

The atonic stomach: a dangerous condition prior to scoliosis surgery.

A dilated atonic stomach as part of neuromuscular or syndromic disorders can have devastating results after scoliosis surgery. Patients can be asymptomatic preoperatively and non-clinical signs can be easily overlooked. Awareness of the condition, however, can prevent severe complications such as aspiration.

Neurological deficits are present in syndromic craniosynostosis patients with and without tonsillar herniation.

BACKGROUND: Children with syndromic craniosynostosis (sCS) have a higher incidence of cerebellar tonsillar herniation (TH) than the general population. In the general population, TH ≥ 5 mm below the foramen magnum is associated with typical neurological deficits but, in sCS, we do not know whether this degree of TH is required before such deficits occur. OBJECTIVE: This prospective cohort study aimed to determine the association between findings on neurological assessment and cerebellar tonsillar position. METHODS: Magnetic resonance imaging (MRI) was used to determine TH ≥ 5 mm and the presence of syringomyelia. In regard to the outcome of neurological deficits, these were categorized according to: A, cerebellar function; B, cranial nerve abnormalities; and C, sensory or motor dysfunction. RESULTS: Twenty of 63 patients with sCS (32% [95% confidence interval 21-45%]) had TH ≥ 5 mm and/or syringomyelia. There was no significant difference in proportion between individual forms of sCS: 16/34 Crouzon, 2/11 Muenke, 2/12 Apert, and 0/7 Saethre-Chotzen patients. Neurological deficits were prevalent (73% [95% confidence interval 60-83%]), and as frequent in patients with TH ≥ 5 mm and/or syringomyelia as those without. Surgery occurred in 3 patients overall, and only in Crouzon patients. CONCLUSION: Determining the effect of TH ≥ 5 mm on neurologic functioning in sCS patients is used to better determine when surgical intervention is warranted. However, we have found that neurological deficits are prevalent in sCS patients, irrespective of cerebellar tonsillar position, suggesting that such findings are developmental and, in part, syndrome-specific central nervous system features.

Introduction of Ultra-High-Field MR Imaging in Infants: Preparations and Feasibility.

BACKGROUND AND PURPOSE: Cerebral MR imaging in infants is usually performed with a field strength of up to 3T. In adults, a growing number of studies have shown added diagnostic value of 7T MR imaging. 7T MR imaging might be of additional value in infants with unexplained seizures, for example. The aim of this study was to investigate the feasibility of 7T MR imaging in infants. We provide information about the safety preparations and show the first MR images of infants at 7T. MATERIALS AND METHODS: Specific absorption rate levels during 7T were simulated in Sim4life using infant and adult models. A newly developed acoustic hood was used to guarantee hearing protection. Acoustic noise damping of this hood was measured and compared with the 3T Nordell hood and no hood. In this prospective pilot study, clinically stable infants, between term-equivalent age and the corrected age of 3 months, underwent 7T MR imaging immediately after their standard 3T MR imaging. The 7T scan protocols were developed and optimized while scanning this cohort. RESULTS: Global and peak specific absorption rate levels in the infant model in the centered position and 50-mm feet direction did not exceed the levels in the adult model. Hearing protection was guaranteed with the new hood. Twelve infants were scanned. No MR imaging-related adverse events occurred. It was feasible to obtain good-quality imaging at 7T for MRA, MRV, SWI, single-shot T2WI, and MR spectroscopy. T1WI had lower quality at 7T. CONCLUSIONS: 7T MR imaging is feasible in infants, and good-quality scans could be obtained.

Signal Change in the Mammillary Bodies after Perinatal Asphyxia.

BACKGROUND AND PURPOSE: Research into memory deficits associated with hypoxic-ischemic encephalopathy has typically focused on the hippocampus, but there is emerging evidence that the medial diencephalon may also be compromised. We hypothesized that mammillary body damage occurs in perinatal asphyxia, potentially resulting in mammillary body atrophy and subsequent memory impairment. MATERIALS AND METHODS: We retrospectively reviewed brain MRIs of 235 clinically confirmed full-term patients with hypoxic-ischemic encephalopathy acquired at a single center during 2004-2017. MRIs were performed within 10 days of birth (median, 6; interquartile range, 2). Two radiologists independently assessed the mammillary bodies for abnormal signal on T2-weighted and DWI sequences. Follow-up MRIs were available for 9 patients; these were examined for evidence of mammillary body and hippocampal atrophy. RESULTS: In 31 neonates (13.2%), abnormal high mammillary body signal was seen on T2-weighted sequences, 4 with mild, 25 with moderate, and 2 with severe hypoxic-ischemic encephalopathy. In addition, restricted diffusion was seen in 6 neonates who had MR imaging between days 5 and 7. For these 31 neonates, the most common MR imaging pattern (41.9%) was abnormal signal restricted to the mammillary bodies with the rest of the brain appearing normal. Follow-up MRIs were available for 9 patients: 8 acquired between 3 and 19 months and 1 acquired at 7.5 years. There was mammillary body atrophy in 8 of the 9 follow-up MRIs. CONCLUSIONS: Approximately 13% of full-term infants with hypoxic-ischemic encephalopathy showed abnormal high mammillary body signal on T2-weighted images during the acute phase, which progressed to mammillary body atrophy in all but 1 of the infants who had follow-up MR imaging. This mammillary body involvement does not appear to be related to the severity of encephalopathy, MR imaging patterns of hypoxic-ischemic encephalopathy, or pathology elsewhere in the brain.

Characteristic MR Imaging Findings of the Neonatal Brain in RASopathies.

BACKGROUND AND PURPOSE: Neuroimaging features in neonates with RASopathies are rarely reported, and to date, there are no neuroimaging studies conducted in this population. Our aim was to investigate the occurrence of supratentorial and posterior fossa abnormalities on brain MRIs of neonates with a RASopathy. MATERIALS AND METHODS: An observational case-control study of neonates with a confirmed RASopathy was conducted. The presence of an intraventricular and/or parenchymal hemorrhage and punctate white matter lesions and assessments of the splenium of the corpus callosum, gyrification of the cortical gray matter, and enlargement of the extracerebral space were noted. The vermis height, transverse cerebellar diameter, cranial base angle, tentorial angle, and infratentorial angle were measured. RESULTS: We reviewed 48 brain MR studies performed at 3 academic centers in 3 countries between 2009 and 2017. Sixteen of these infants had a genetically confirmed RASopathy (group 1), and 32 healthy infants were enrolled as the control group (group 2). An increased rate of white matter lesions, extracerebral space enlargement, simplification of the cortical gyrification, and white matter abnormalities were seen in group 1 (P < .001, for each). The vermis height of patients was significantly lower, and tentorial and infratentorial angles were significantly higher in group 1 (P = .01, P < .001, and P = .001, respectively). CONCLUSIONS: Neonates with a RASopathy had characteristic structural and acquired abnormalities in the cortical gray matter, white matter, corpus callosum, cerebellum, and posterior fossa. This study provides novel neuroimaging findings on supratentorial and posterior fossa abnormalities in neonates with a RASopathy.

A New Ultrasound Marker for Bedside Monitoring of Preterm Brain Growth.

BACKGROUND AND PURPOSE: Preterm neonates are at risk for neurodevelopmental impairment, but reliable, bedside-available markers to monitor preterm brain growth during hospital stay are still lacking. The aim of this study was to assess the feasibility of corpus callosum-fastigium length as a new cranial sonography marker for monitoring of preterm brain growth. MATERIALS AND METHODS: In this longitudinal prospective cohort study, cranial ultrasound was planned on the day of birth, days 1, 2, 3, and 7 of life; and then weekly until discharge in preterm infants born before 29 weeks of gestational age. Reproducibility and associations between clinical variables and corpus callosum-fastigium growth trajectories were studied. RESULTS: A series of 1-8 cranial ultrasounds was performed in 140 infants (median gestational age at birth, 27(+2) weeks (interquartile range, 26(+1) to 28(+1); 57.9% male infants). Corpus callosum-fastigium measurements showed good-to-excellent agreement for inter- and intraobserver reproducibility (intraclass correlation coefficient >0.89). Growth charts for preterm infants between 24 and 32 weeks of gestation were developed. Male sex and birth weight SD score were positively associated with corpus callosum-fastigium growth rate. CONCLUSIONS: Corpus callosum-fastigium length measurement is a new reproducible marker applicable for bedside monitoring of preterm brain growth during neonatal intensive care stay.

Abnormal transcranial Doppler cerebral blood flow velocity and blood pressure profiles in children with syndromic craniosynostosis and papilledema.

OBJECTIVE: Children with syndromic craniosynostosis are at risk of intracranial hypertension. This study aims to examine patient profiles of transcranial Doppler (TCD) cerebral blood flow velocity (CBFv) and systemic blood pressure (BP) in subjects with and without papilledema at the time of surgery, and subsequent effect of cranial vault expansion. METHODS: Prospective study of patients treated at a national referral center. Patients underwent TCD of the middle cerebral artery 1 day before and 3 weeks after surgery. Measurements included mean CBFv, peak systolic velocity, and end diastolic velocity; age-corrected resistive index (RI) was calculated. Systemic BP was recorded. Papilledema was used to indicate intracranial hypertension. RESULTS: Twelve patients (mean age 3.1 years, range 0.4-9.5) underwent TCD; 6 subjects had papilledema. Pre-operatively, patients with papilledema, in comparison to those without, had higher TCD values, RI, and BP (all p = 0.04); post-operatively, the distinction regarding BP remained (p = 0.04). There is a significant effect of time following vault surgery with a decrease in RI (p < 0.01). CONCLUSION: Patients with syndromic craniosynostosis who have papilledema have a different TCD profile with raised BP. Vault surgery results in increased CBFv and decrease in RI, however the associated systemic BP response to intracranial hypertension remained at short-term follow-up.

Diffusion Tensor Imaging and Fiber Tractography in Children with Craniosynostosis Syndromes.

BACKGROUND AND PURPOSE: Patients with craniosynostosis syndromes caused by mutations in FGFR-2, FGFR-3, and TWIST1 genes are characterized by having prematurely fused skull sutures and skull base synchondroses, which result in a skull deformity and are accompanied by brain anomalies, including altered white matter microarchitecture. In this study, the reliability and reproducibility of DTI fiber tractography was investigated in these patients. The outcomes were compared with those of controls. MATERIALS AND METHODS: DTI datasets were acquired with a 1.5T MR imaging system with 25 diffusion gradient orientations (voxel size = 1.8 × 1.8 × 3.0 mm(3), b-value = 1000 s/mm(2)). White matter tracts studied included the following: corpus callosum, cingulate gyrus, fornix, corticospinal tracts, and medial cerebellar peduncle. Tract pathways were reconstructed with ExploreDTI in 58 surgically treated patients with craniosynostosis syndromes and 7 controls (age range, 6-18 years). RESULTS: Because of the brain deformity and abnormal ventricular shape and size, DTI fiber tractography was challenging to perform in patients with craniosynostosis syndromes. To provide reliable tracts, we adapted standard tracking protocols. Fractional anisotropy was equal to that in controls (0.44 versus 0.45 ± 0.02, P = .536), whereas mean, axial, and radial diffusivity parameters of the mean white matter were increased in patients with craniosynostosis syndromes (P < .001). No craniosynostosis syndrome-specific difference in DTI properties was seen for any of the fiber tracts studied in this work. CONCLUSIONS: Performing DTI fiber tractography in patients with craniosynostosis syndromes was difficult due to partial volume effects caused by an anisotropic voxel size and deformed brain structures. Although these patients have a normal fiber organization, increased diffusivity parameters suggest abnormal microstructural tissue properties of the investigated white matter tracts.

Atypical presentation of a newborn with Apert syndrome.

INTRODUCTION: Apert syndrome is a rare syndrome characterized by a consistent phenotype including bilateral coronal suture synostosis with an enlarged anterior fontanel, midface hypoplasia, and complex symmetric syndactyly of hands and feet. CASE REPORT: We present a boy with Apert syndrome caused by the pathogenic c.755C > G p.Ser252Trp mutation in the FGFR2 gene with atypical characteristics, including premature fusion of the metopic suture with a small anterior fontanel, hypotelorism, and a massive posterior fontanel. Directly after birth, he showed papilledema, epilepsy, and central apneas. CONCLUSION: We present a newborn with Apert syndrome with atypical craniofacial presentation.

Developmental venous anomaly in the newborn brain.

INTRODUCTION: Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. METHODS: Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. RESULTS: DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. CONCLUSIONS: This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age.

Choice of diffusion tensor estimation approach affects fiber tractography of the fornix in preterm brain.

BACKGROUND AND PURPOSE: Neonatal DTI enables quantitative assessment of microstructural brain properties. Although its use is increasing, it is not widely known that vast differences in tractography results can occur, depending on the diffusion tensor estimation methodology used. Current clinical work appears to be insufficiently focused on data quality and processing of neonatal DTI. To raise awareness about this important processing step, we investigated tractography reconstructions of the fornix with the use of several estimation techniques. We hypothesized that the method of tensor estimation significantly affects DTI tractography results. MATERIALS AND METHODS: Twenty-eight DTI scans of infants born <29 weeks of gestation, acquired at 30-week postmenstrual age and without intracranial injury observed, were prospectively collected. Four diffusion tensor estimation methods were applied: 1) linear least squares; 2) weighted linear least squares; 3) nonlinear least squares, and 4) robust estimation of tensors by outlier rejection. Quality of DTI data and tractography results were evaluated for each method. RESULTS: With nonlinear least squares and robust estimation of tensors by outlier rejection, significantly lower mean fractional anisotropy values were obtained than with linear least squares and weighted linear least squares. Visualized quality of tract reconstruction was significantly higher by use of robust estimation of tensors by outlier rejection and correlated with quality of DTI data. CONCLUSIONS: Quality assessment and choice of processing methodology have considerable impact on neonatal DTI analysis. Dedicated acquisition, quality assessment, and advanced processing of neonatal DTI data must be ensured before performing clinical analyses, such as associating microstructural brain properties with patient outcome.

Optimal timing of cerebral MRI in preterm infants to predict long-term neurodevelopmental outcome: a systematic review.

SUMMARY: Advances in neonatal neuroimaging have improved detection of preterm brain injury responsible for abnormal neuromotor and cognitive development. Increasingly sophisticated MR imaging setups allow scanning during early preterm life. In this review, we investigated how brain MR imaging in preterm infants should be timed to best predict long-term outcome. Given the strong evidence that structural brain abnormalities are related to long-term neurodevelopment, MR imaging should preferably be performed at term-equivalent age. Early MR imaging is promising because it can guide early intervention studies and is indispensable in research on preterm brain injury.