Term-equivalent Magnetic Resonance Imaging Research Articles

Prechtl’s General Movements performed at writhing age may help target MRI use in the NICU (P9-9.012)

<h3>Objective:</h3> We aimed to determine if Prechtl’s general movement assessment (GMA) could help target the use of magnetic resonance imaging (MRI) in the neonatal intensive care unit (NICU) to detect infants with neuroimaging abnormalities not detected by cranial ultrasound (CUS) alone. <h3>Background:</h3> Prechtl’s GMA is a bedside evaluation performed to identify infants at high-risk for neurological and motor disorders such as cerebral palsy (CP). Cramped synchronized (CS) GMA at writhing age has been associated with poor neuromotor outcomes. However, no clinical practice guideline exists to recommend routine use of term-equivalent MRI in infants with CS GMAs. <h3>Design/Methods:</h3> We retrospectively reviewed neuroimaging reports from pediatric neuroradiologists of all infants who had CS GMA between 36 and 44 weeks post-menstrual age at two level III and three level IV NICUs. All three sites used standard protocols for preterm neuroimaging with at least one CUS in the first week after birth and another near 30 weeks corrected gestational age. If an MRI was obtained (due to clinical suspicion for intracranial abnormality, abnormal CUS findings, or CS GMA) the reason for performing the MRI was recorded. <h3>Results:</h3> 144 infants had CS GMA, and of these, only 19 did not receive neuroimaging. Initial neuroimaging demonstrated abnormal (mild and severe) findings in 64.5% and clinically significant in 45.6%. When MRI was performed secondarily, agreement between the two types of imaging occurred most of the time. A higher level of insult was present in 20.7% of those receiving a secondary MRI. The frequency of clinically significant abnormal findings on final determination was 48.8%. In 14 cases, secondary MRI was performed in response to GMA CS pattern only; in this case, MRI was abnormal in 11 (76.8%) cases. <h3>Conclusions:</h3> These results suggest that infants with CS GMA at writhing age may represent a population with a high-likelihood of clinically significant abnormal neuroimaging findings. <b>Disclosure:</b> Dr. Chirigos has nothing to disclose. Dr. Burton has nothing to disclose. Dr. Maitre has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Thrive Neuromedical. Dr. Maitre has stock in Thrive Neuromedical. Dr. Ostrander has nothing to disclose.

MRI Findings in Prematurely-Born Adolescents and Young Adults Who Screen Positive for Autism Spectrum Disorder

Autism spectrum disorder (ASD) is three to four times more common in prematurely-born children (<37 weeks' gestation) than term-born children.1 The relationship between lower gestational age and ASD is independent of familial and environmental factors, suggesting a potential causal link.2 Term-equivalent magnetic resonance imaging (MRI) findings do not reliably predict ASD in preterm infants,3 and little is known about MRI findings in preterm children with ASD imaged later in childhood. To address this gap, we screened adolescents and young adults for ASD as part of a longitudinal cohort study of MRI in preterm infants4 and compared neonatal and follow-up MRI findings by ASD screening status.

Trajectory of the incidence of brushes on preterm electroencephalogram and its association with neurodevelopment in extremely low birth weight infants

BackgroundBrush or delta brush is a well-known characteristic waveform in preterm electroencephalograms. However, the longitudinal trajectory of brushes and its association with neurodevelopment remain uncertain. MethodsWe analyzed the longitudinal incidence of brushes in 36 extremely low birth weight infants without severe brain lesions and its association with neurodevelopment and white matter abnormality. Conventional eight-channel electroencephalograms were recorded at 30, 32, 36, and 40 postmenstrual weeks (PMW). Incidence of brushes was calculated as the sum of brushes from each channel separated by active sleep and quiet sleep. A developmental delay was defined as a developmental quotient of <85 assessed at corrected age of 18 months. White matter abnormalities were evaluated with term-equivalent magnetic resonance imaging. ResultsThe median incidence of brushes (per minute) in 36 infants at PMW 30, 32, 36, and 40 was 16.4, 20.4, 22.5, and 1.8 during active sleep and 7.5, 10.3, 11.5, and 1.7 during quiet sleep, respectively. Among the 36 infants, 14 infants were diagnosed with developmental delay. Longitudinal trajectories of the incidence of brushes were different between the normal and the delayed development groups. Brushes were observed most frequently at 36 PMW in the delayed development group. The incidence of brushes at 36 PMW was significantly correlated with the severity of white matter abnormalities and negatively correlated with the developmental quotient. ConclusionThe incidence of brushes at 36 PMW can be a unique predictor of early neurodevelopment in extremely low birth weight infants without severe brain lesions.

Specific cognitive deficits in preschool age correlated with qualitative and quantitative MRI parameters in prematurely born children

Cognitive deficits after perinatal brain lesion in preterm infants are among the most common neurodevelopmental disturbances. The relationship between structural changes on at term magnetic resonance imaging (MRI) and cognitive deficits in the preschool age should be a special focus due to timely intervention. The aim of this study was to correlate qualitative and quantitative MRI parameters of perinatal brain lesion in preterm children, on early neonatal MRI and follow up MRI, with general and specific cognitive functions in the preschool age. Twenty-one preterm infants with verified perinatal lesions based on clinical and ultrasound data underwent a brain MRI at term-equivalent age and a second MRI between 3 and 5 years of age. Qualitative and quantitative MRI analyses were done. All subjects underwent cognitive assessment (3-5 years) using Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Developmental Neuropsychological Assessment (NEPSY-II). Results show that many structural changes on at term MRI and on follow up MRI in preterm born children moderately correlate with specific cognitive deficits in preschool age. At term equivalent MRI, white matter changes and cortical thickness correlate to general and specific cognitive functions in infants born preterm. By analyzing follow up MRI at preschool age, structural changes of different white matter segments, corpus callosum, cortical thickness and lobe volume correlate to some specific cognitive functions. Besides general cognitive delay, specific cognitive deficits in preterm children should be targeted in research and intervention, optimally combined with MRI scanning, providing timely and early intervention of cognitive deficits after perinatal brain lesion. Our results, as well as previously published results, suggest the importance of detailed preschool neuropsychological assessment, prior to enrolment in the school system. Although preliminary, our results expand our understanding of the relationship between early brain developmental lesions and cognitive outcome following premature birth.

Clinical impact of term-equivalent magnetic resonance imaging in extremely low-birth-weight infants at a regional NICU.

To evaluate the clinical impact of routine term-equivalent magnetic resonance imaging (TE-MRI) for extremely low-birth-weight infants at a regional neonatal intensive care unit. This is a single-center retrospective study evaluating preterm survivors who underwent TE-MRI. MRI abnormalities were compared between infants with and without cranial ultrasonography (CUS) abnormalities. Cost analysis comparing imaging modalities was also performed. TE-MRI use increased from 17% in 2006 to 76% in 2010. MRI detected new findings in nearly half of infants, whether or not they had known ultrasound abnormalities. MRI detected more cerebellar (18% vs 6%, P=0.04) and moderate white matter injury (12% vs 7%, P<0.001), and altered simulated neurological prognosis across developmental domains. The cost of TE-MRI was $1600, which was comparable to serial CUSs. TE-MRI detects new abnormalities and impacts developmental prognosis in the extremely low birth weight, which supports its use despite the added financial cost.

Corticospinal Tract Injury Precedes Thalamic Volume Reduction in Preterm Infants with Cystic Periventricular Leukomalacia

ObjectivesTo measure both fractional anisotropy (FA) values in the corticospinal tracts (CSTs) and volume of the thalami in preterm infants with cystic periventricular leukomalacia (c-PVL) and to compare these measurements with control infants.Study designPreterm infants with c-PVL and controls with magnetic resonance imaging data acquired between birth and term equivalent age (TEA) were retrospectively identified in 2 centers. Tractography of the CST and segmentation of the thalamus were performed, and values from infants with c-PVL and controls were compared.ResultsThirty-three subjects with c-PVL and 31 preterm controls were identified. All had at least 1 scan up to TEA, and multiple scans were performed in 31 infants. A significant difference in FA values of the CST was found between cases and controls on the scans both before and at TEA. Absolute thalamic volumes were significantly reduced at TEA but not on the earlier scans. Data acquired in infancy showed lower FA values in infants with c-PVL.ConclusionsDamage to the CST can be identified on the early scan and persists, whereas the changes in thalamic volume develop in the weeks between the early and term equivalent magnetic resonance imaging. This may reflect the difference between acute and remote effects of the extensive injury to the white matter caused by c-PVL.

Regional Brain Biometrics at Term-Equivalent Age and Developmental Outcome in Extremely Low-Birth-Weight Infants.

This study aims to evaluate individual regional brain biometrics and their association with developmental outcome in extremely low-birth-weight (ELBW) infants. This is a retrospective study evaluating term-equivalent magnetic resonance imaging (TE-MRI) from 27 ELBW infants with known developmental outcomes beyond 12 months corrected age. Regional biometric measurements were performed by a pediatric neuroradiologist blinded to outcome data. Measures included biparietal width, transcerebellar diameter (TCD), deep gray matter area (DGMA), ventricular dilatation, corpus callosum, and interhemispheric distance. The relationship between regional biometrics and Bayley-II developmental scores were evaluated with linear regression models. The study cohort had an average±standard deviation birth weight of 684±150 g, gestational age of 24.6±2 weeks and 48% males. DGMA was significantly associated with both cognitive and motor outcomes. Significant associations were also observed between TCD and corpus callosum splenium with cognitive and motor outcomes, respectively. Other biometric measures were not associated with outcome (p>0.05). DGMA<10.26 cm2 was highly specific for poor motor and cognitive outcome. TE-MRI biometrics reflecting impaired deep gray matter, callosal, and cerebellar size is associated with worse early childhood cognitive and motor outcomes. DGMA may be the most robust single biometric measure to predict adverse developmental outcome in preterm survivors.

Normative amplitude-integrated EEG measures in preterm infants.

ObjectiveAssessing qualitative patterns of amplitude integrated EEG (aEEG) maturation of preterm infants requires personnel with training in interpretation and an investment of time. Quantitative algorithms provide a method for rapidly and reproducibly assessing an aEEG recording independent of provider skill level. Although there are several qualitative and quantitative normative datasets in the literature, this study provides the broadest array of quantitative aEEG measures in a carefully selected and followed cohort of preterm infants with mild or no visible injury on term equivalent MRI and subsequently normal neurodevelopment at 2 and 7 years of age.Study DesignA two-channel aEEG recording was obtained on days 4,7,14, and 28 of life for infants born ≤30 weeks EGA. Measures of amplitude and continuity, spectral edge frequency, percentage of trace in interburst interval, interburst interval length, and frequency counts of smooth delta waves, delta brushes and theta bursts were obtained. MRI was obtained at term-equivalent age (TEA) and neurodevelopmental testing was conducted at 2 and 7 years of corrected age.ResultCorrelations were found between increasing post-menstrual age (PMA) and decreasing maximum amplitude (R=−0.23, p=0.05), increasing minimum amplitude (R=0.46, p=0.002), and increasing spectral edge frequency (R=0.78, p=4.17x10−14). Negative correlations were noted between increasing PMA and counts of smooth delta waves (R=−0.39, p=0.001), delta brushes (R=−0.37, p=0.003), and theta bursts (R=−0.61, p=5.66x10−8). Increasing PMA was also associated with a decreased amount of time spent in the interburst interval (R=−0.38, p=0.001) and a shorter length of the maximum IBI (R=−0.27, p=0.03).ConclusionThis analysis supports a strong correlation between quantitatively determined aEEG measures and PMA, in a cohort of preterm infants with normal TEA neuroimaging and neurodevelopmental outcomes at 7 years of age, which is both predictable and reproducible. These “normative” quantitative values support the pattern of maturation previously identified by qualitative analysis.

Magnetic resonance imaging of the brain at term equivalent age in extremely premature neonates: To scan or not to scan?

In the last decade, the role of magnetic resonance imaging (MRI) in neonatal care for prematurely born infants has rapidly expanded and evolved. Recent investigations addressed many of the practical issues pertaining to image acquisition and interpretation, enabling high-quality MR images to be obtained without sedating medications in preterm infants at any institution. Expanded application has demonstrated that MRI provides superior ability to assess cerebral development and identify and define cerebral injury in comparison to other imaging modalities. Term equivalent MRI results have been shown to correlate with neurodevelopmental outcomes, providing improved predictive ability over other neuroimaging, clinical or physical examination measures. Regular utilisation of MRI in this population is fundamental to gaining the knowledge and expertise necessary for rational, accurate application. Ongoing experiences will continue to shape the nature and type of information available to clinicians and families using MRI, further refining its role as a routine element of neonatal care.