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Background We previously reported that increasing severity of watershed (WS) injury in neonatal magnetic resonance imaging (MRI) is associated with worse language outcomes in early childhood. In the present study, we investigated the relationship between neonatal injury patterns and cognitive profile in adolescents with neonatal encephalopathy. Methods Term neonates with encephalopathy were prospectively enrolled and imaged using brain MRI from 1999 to 2008. Neonatal brain injury was scored according to the degree of injury in WS and basal ganglia/thalamus (BG/T) areas. The children underwent a neurocognitive assessment and follow-up brain MRI at the age of 10–16 years. The relationship between neonatal brain injury patterns and adolescent cognitive outcomes was assessed. Results In a cohort of 16 children, neonatal MRI showed WS injury in 7, BG/T injury in 2, and normal imaging in 7. Children with WS injury had lower estimated overall cognitive ability than those with normal imaging. Increasing WS injury score was associated with decreasing estimated overall cognitive ability, Perceptual Reasoning Index, and digit span score. Conclusions Children with the WS injury are at an increased risk of having problems in long-term intellectual ability. These cognitive outcomes may underlie early language difficulties seen in children with neonatal WS injury. Impact Adolescents with a history of neonatal encephalopathy and watershed pattern of injury on neonatal brain magnetic resonance imaging (MRI) had lower overall cognitive ability, perceptual reasoning skills, and auditory working memory than those with normal neonatal imaging. Children with post-neonatal epilepsy and cerebral palsy had the worst cognitive outcomes. Watershed pattern of injury confers high long-term differences in intellectual ability.

Punctate white matter lesions (PWML) are common in preterm neonates and have also been reported in the full term. While most studies focus on white matter abnormalities, gray matter (GM) alterations are generally ignored due to the lack of abnormalities on conventional MRI. This study aims to investigate whether magnetic resonance spectroscopy is a sensitive and practical method to detect occult alterations of deep GM nuclei in these neonates. Neonates with PWML and controls with no MRI abnormalities were retrospectively studied. Apparent diffusion coefficient values and metabolic ratios (Cho/Cr, NAA/Cho, and NAA/Cr) in the lenticular nucleus and the thalamus were compared between the PWML and control groups. Forty-two neonates with PWML (grades I, II, and III contained 14, 21, and 7 subjects, respectively) and 50 controls were enrolled. Apparent diffusion coefficient values in the lenticular nucleus and the thalamus were not significantly different between the PWML and the control groups. The NAA/Cho ratio was significantly lower in the PWML group than in the control group in both regions, whereas a lower NAA/Cr ratio was only observed in the thalamus. Significantly lower ratios of NAA/Cho in both regions and NAA/Cr in the thalamus were detected in the grade II and III subgroup, whereas the thalamic NAA/Cho ratio was decreased in the grade I group compared with controls. Magnetic resonance spectroscopy is a sensitive method for detecting the occult deep GM abnormalities for the study cohort of neonates with PWML when compared with subjects without PWML.

Author(s): Kamino, Daphne; Chau, Vann; Studholme, Colin; Liu, Mengyuan; Xu, Duan; Barkovich, A James; Ferriero, Donna M; Miller, Steven P; Brant, Rollin; Tam, Emily WY | Abstract: BackgroundTo assess whether postnatal plasma cholesterol levels are associated with microstructural and macrostructural regional brain development in preterm newborns.MethodsSixty preterm newborns (born 24-32 weeks gestational age) were assessed using MRI studies soon after birth and again at term-equivalent age. Blood samples were obtained within 7 days of each MRI scan to analyze for plasma cholesterol and lathosterol (a marker of endogenous cholesterol synthesis) levels. Outcomes were assessed at 3 years using the Bayley Scales of Infant Development, Third Edition.ResultsEarly plasma lathosterol levels were associated with increased axial and radial diffusivities and increased volume of the subcortical white matter. Early plasma cholesterol levels were associated with increased volume of the cerebellum. Early plasma lathosterol levels were associated with a 2-point decrease in motor scores at 3 years.ConclusionsHigher early endogenous cholesterol synthesis is associated with worse microstructural measures and larger volumes in the subcortical white matter that may signify regional edema and worse motor outcomes. Higher early cholesterol is associated with improved cerebellar volumes. Further work is needed to better understand how the balance of cholesterol supply and endogenous synthesis impacts preterm brain development, especially if these may be modifiable factors to improve outcomes.

Magnetic resonance imaging (MRI) is the workhorse modality in pediatric neuroimaging because it provides excellent soft-tissue contrast without ionizing radiation. Until recently, studies were uninterpretable without sedation; however, given development of shorter sequences, sequences that correct for motion, and studies showing the potentially deleterious effects of sedation on immature laboratory animals, it is prudent to minimize sedation when possible. This manuscript provides basic guidelines for performing pediatric neuro MRI without sedation by both modifying technical factors to reduce scan time and noise, and using a multi-disciplinary team to coordinate imaging with the patient's biorhythms.

Preterm birth has a dramatic impact on polyunsaturated fatty acid exposures for the developing brain. This study examined the association between postnatal fatty acid levels and measures of brain injury and development, as well as outcomes. A cohort of 60 preterm newborns (24–32 wk gestational age) was assessed using early and near-term magnetic resonance imaging (MRI) studies. Red blood cell fatty acid composition was analyzed coordinated with each scan. Outcome at a mean of 33 mo corrected age was assessed using the Bayley Scales of Infant Development, 3rd edition. Adjusting for confounders, a 1% increase in postnatal docosahexaenoic acid (DHA) levels at early MRI was associated with 4.3-fold decreased odds of intraventricular hemorrhage, but was not associated with white matter injury or cerebellar haemorrhage. Higher DHA and lower linoleic acid (LA) levels at early MRI were associated with lower diffusivity in white matter tracts and corresponding improved developmental scores in follow-up. Higher DHA and lower LA levels in the first few weeks of life are associated with decreased intraventricular haemorrhage, improved microstructural brain development, and improved outcomes in preterm born children. Early and possibly antenatal interventions in high-risk pregnancies need to be studied for potential benefits in preterm developmental outcomes.

Diffusion imaging has made significant inroads into the clinical diagnosis of a variety of diseases by inferring changes in microstructure, namely cell membranes, myelin sheath and other structures that inhibit water diffusion. This review discusses recent progress in the use of diffusion parameters in predicting functional outcome. Studies in the literature using only scalar parameters from diffusion measurements, such as apparent diffusion coefficient (ADC) and fractional anisotropy (FA), are summarized. Other more complex mathematical models and post-processing uses are also discussed briefly.

Investigation of optical absorption in ∼25μm thick, monocrystalline silicon (Si) substrates obtained from a novel exfoliation technique is done by fabricating solar cells with single heterojunction architecture (without using intrinsic amorphous silicon layer) with diffused back junction and local back contact. The ease of process flow and the rugged and flexible nature of the substrates due to thick metal backing enables use of various light-trapping and optical absorption enhancement schemes traditionally practiced in the industry for thicker (>120μm) substrates. Optical measurement of solar cells using antireflective coating, texturing on both surfaces, and back surface dielectric/metal stack as mirror to reflect the long wavelength light from the back surface show a very low front surface reflectance of 4.6% in the broadband spectrum (300nm-1200nm). The illuminated current voltage (IV) and external quantum efficiency (EQE) measurement of such solar cell shows a high integrated current density of 34.4mA/cm2, which implies significant internal photon reflection. Our best cell with intrinsic amorphous silicon (i-a-Si) layer with only rear surface textured shows an efficiency of 14.9%. EQE data shows improved blue response and current density due to better front surface passivation. Simulations suggest that with optimized light trapping and surface passivation, such thin c-Si cells can reach efficiencies >20%.

The hippocampal formation plays an important role in learning and memory, however data on its development in utero in humans is limited. This study was performed to evaluate hippocampal development in healthy fetuses using 3D reconstructed magnetic resonance imaging (MRI). A cohort of 20 healthy pregnant women underwent prenatal MRI at a median gestational age of 24.9 weeks (range 21.3-31.9 weeks); 6 of the women also had a second fetal MRI performed at a 6 week interval. Routine 2D ultrafast T2-weighted images were used to reconstruct a 3D volume image, which was then used to manually segment the right and left hippocampi. Total hippocampal volume was calculated for each subject and compared against gestational age. There was a linear increase in total hippocampal volume with increasing gestational age (P

Cerebellar injury has been increasingly recognized as a complication of preterm birth, with decreased cerebellar volumes seen on follow-up neuroimaging. A cohort of 38 preterm newborns, including 14 with two scans, was studied with MRI, including single-shot fast spin-echo (SSFSE) diffusion tensor imaging (DTI) sequence specifically to assess the posterior fossa. Early changes in the cerebellum (apparent diffusion coefficient (ADC) and fractional anisotropy (FA)) were assessed and correlated with supratentorial manifestations of injury (intraventricular hemorrhage (IVH) or white matter injury (WMI)). ADC decreased and FA increased with increasing gestational age in both cerebellar grey and white matter. Severe IVH was associated with increased ADC in the middle cerebellar peduncles and hila of the cerebellar nuclei, decreased ADC in the cerebellar cortex, and decreased FA in all three regions. Changes with WMI were not consistent. Significant developmental changes in water diffusion were seen in cerebellar grey and white matter that were altered in patients with supratentorial IVH. DTI studies may provide an early indicator for cerebellar injury and abnormal cerebellar development in preterm neonates.