Effects of neurodevelopmental risk factors on brainstem maturation in premature infants.

BACKGROUND: Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA). METHODS: Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded. RESULTS: Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level. CONCLUSIONS: Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation. IMPACT: Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

Early Neonatal C-Reactive Protein Levels and Periventricular Leukomalacia.

BACKGROUND: Cystic periventricular leukomalacia (cPVL) is a strong indicator of subsequent motor and developmental impairments in premature infants. There is a paucity of publications on biomarkers of cPVL. OBJECTIVES: To determine C-reactive protein (CRP) levels during the first week of life of preterm infants who later developed cPVL and to identify the association between CRP levels with perinatal factors. METHODS: We retrospectively included infants ≤ 32 weeks gestation and/or birth weights ≤ 1500 grams; 17 with a cranial ultrasound diagnosis of cPVL and 54 with normal ultrasounds. Serum CRP levels were measured during days 1-7 (CRP1-7d) of life and subdivided into two timing groups: days 1-3 (CRP1-3d) and days 4-7 (CRP4-7d). RESULTS: The cPVL group had significantly higher mean CRP4-7d levels compared to controls (12.75 ± 21.2 vs. 2.23 ± 3.1, respectively, P = 0.03), while CRP1-3d levels were similar. CRP1-7d levels were significantly correlated with maximal fraction of inspired oxygen during the first 12 hours of life (FiO2-12h, r = 0.51, P < 0.001]. Additional risk factors were not associated with CRP levels. CONCLUSIONS: Our finding of elevated CRP4-7d levels and later development of cPVL supports earlier studies on the involvement of inflammation in the pathogenesis of cPVL. Whether CRP could serve as a biomarker of cPVL and its correlation with outcomes, awaits further trials. Furthermore, the correlation between FiO2-12h and CRP1-7d levels suggest that hypoxia and/or hyperoxia may serve as a trigger in the activation of inflammation during the first days of life of preterm infants.

The impact of extrauterine life on visual maturation in extremely preterm born infants.

BACKGROUND: Extrauterine life is an important factor when considering brain maturation. Few studies have investigated the development of visual evoked potentials (VEP) in extremely preterm infants, and only a minority have taken into consideration the impact of extrauterine life. The aim of this study was to assess the normal maturation of VEP in infants born prior to 29 weeks gestational age (GA) and to explore the potential influence of extrauterine life. METHODS: VEP were prospectively recorded in extremely preterm infants, and principal peaks (N0, N1, P1, N2, P2, N3) were identified. The mean of peak-time and percentages of peak appearances were assessed for three GA groups (23/24, 25/26, 27/28 weeks) and four subgroups of increasing postnatal age (PNA), up to 8 weeks after birth. RESULTS: A total of 163 VEP recordings in 38 preterm infants were analyzed. With increasing GA at birth, peak-times decreased. When comparing infants with equal GA but longer extrauterine life, those with the highest PNA demonstrated the shortest VEP peak-times. However, this effect was less present in infants born prior to 25 weeks GA. CONCLUSION: Provided that a certain maturational threshold is reached, extrauterine life appears to accelerate maturation of the visual system in preterm infants.

Prediction of Periventricular Leukomalacia in Neonates after Cardiac Surgery Using Machine Learning Algorithms.

Periventricular leukomalacia (PVL) is brain injury that develops commonly in neonates after cardiac surgery. Earlier identification of patients who are at higher risk for PVL may improve clinicians' ability to optimize care for these challenging patients. The aim of this study was to apply machine learning algorithms and wavelet analysis to vital sign and laboratory data obtained from neonates immediately after cardiac surgery to predict PVL occurrence. We analyzed physiological data of patients with and without hypoplastic left heart syndrome (HLHS) during the first 12 h after cardiac surgery. Wavelet transform was applied to extract time-frequency information from the data. We ranked the extracted features to select the most discriminative features, and the support vector machine with radial basis function as a kernel was selected as the classifier. The classifier was optimized via three methods: (1) mutual information, (2) modified mutual information considering the reliability of features, and (3) modified mutual information with reliability index and maximizing set's mutual information. We assessed the accuracy of the classifier at each time point. A total of 71 neonates met the study criteria. The rates of PVL occurrence were 33% for all patients, with 41% in the HLHS group and 25% in the non-HLHS group. The F-score results for HLHS patients and non-HLHS patients were 0.88 and 1.00, respectively. Using maximizing set's mutual information improved the classifier performance in the all patient groups from 0.69 to 0.81. The novel application of a modified mutual information ranking system with the reliability index in a PVL prediction model provided highly accurate identification. This tool is a promising step for improving the care of neonates who are at higher risk for developing PVL following cardiac surgery.

Predicting 2-y outcome in preterm infants using early multimodal physiological monitoring.

BACKGROUND: Preterm infants are at risk of adverse outcome. The aim of this study is to develop a multimodal model, including physiological signals from the first days of life, to predict 2-y outcome in preterm infants. METHODS: Infants <32 wk gestation had simultaneous multi-channel electroencephalography (EEG), peripheral oxygen saturation (SpO2), and heart rate (HR) monitoring. EEG grades were combined with gestational age (GA) and quantitative features of HR and SpO2 in a logistic regression model to predict outcome. Bayley Scales of Infant Development-III assessed 2-y neurodevelopmental outcome. A clinical course score, grading infants at discharge as high or low morbidity risk, was used to compare performance with the model. RESULTS: Forty-three infants were included: 27 had good outcomes, 16 had poor outcomes or died. While performance of the model was similar to the clinical course score graded at discharge, with an area under the receiver operator characteristic (AUC) of 0.83 (95% confidence intervals (CI): 0.69-0.95) vs. 0.79 (0.66-0.90) (P = 0.633), the model was able to predict 2-y outcome days after birth. CONCLUSION: Quantitative analysis of physiological signals, combined with GA and graded EEG, shows potential for predicting mortality or delayed neurodevelopment at 2 y of age.

Slow pupillary light responses in infants at high risk of cerebral palsy were associated with periventricular leukomalacia and neurological outcome.

AIM: Having observed slow pupillary light responses (PLRs) in infants at high risk of cerebral palsy, we retrospectively evaluated whether these were associated with specific brain lesions or unfavourable outcomes. METHODS: We carried out neurological examinations on 30 infants at very high risk of cerebral palsy five times until the corrected age of 21 months, classifying each PLR assessment as normal or slow. The predominant reaction during development was determined for each infant. Neonatal brain scans were classified based on the type of brain lesion. Developmental outcome was evaluated at 21 months of corrected age with a neurological examination, the Bayley Scales of Infant Development Second Edition and the Infant Motor Profile. RESULTS: Of the 30 infants, 16 developed cerebral palsy. Predominantly slow PLRs were observed in eight infants and were associated with periventricular leukomalacia (p = 0.007), cerebral palsy (p = 0.039), bilateral cerebral palsy (p = 0.001), poorer quality of motor behaviour (p < 0.0005) and poorer cognitive outcome (p = 0.045). CONCLUSION: This explorative study suggested that predominantly slow PLR in infants at high risk of cerebral palsy were associated with periventricular leukomalacia and poorer developmental outcome. Slow PLR might be an expression of white matter damage, resulting in dysfunction of the complex cortico-subcortical circuitries.

The expanding phenotype of COL4A1 and COL4A2 mutations: clinical data on 13 newly identified families and a review of the literature.

Two proα1(IV) chains, encoded by COL4A1, form trimers that contain, in addition, a proα2(IV) chain encoded by COL4A2 and are the major component of the basement membrane in many tissues. Since 2005, COL4A1 mutations have been known as an autosomal dominant cause of hereditary porencephaly. COL4A1 and COL4A2 mutations have been reported with a broader spectrum of cerebrovascular, renal, ophthalmological, cardiac, and muscular abnormalities, indicated as "COL4A1 mutation-related disorders." Genetic counseling is challenging because of broad phenotypic variation and reduced penetrance. At the Erasmus University Medical Center, diagnostic DNA analysis of both COL4A1 and COL4A2 in 183 index patients was performed between 2005 and 2013. In total, 21 COL4A1 and 3 COL4A2 mutations were identified, mostly in children with porencephaly or other patterns of parenchymal hemorrhage, with a high de novo mutation rate of 40% (10/24). The observations in 13 novel families harboring either COL4A1 or COL4A2 mutations prompted us to review the clinical spectrum. We observed recognizable phenotypic patterns and propose a screening protocol at diagnosis. Our data underscore the importance of COL4A1 and COL4A2 mutations in cerebrovascular disease, also in sporadic patients. Follow-up data on symptomatic and asymptomatic mutation carriers are needed for prognosis and appropriate surveillance.

Scoring system for periventricular leukomalacia in infants with congenital heart disease.

BACKGROUND: Currently two magnetic resonance imaging (MRI) methods have been used to assess periventricular leukomalacia (PVL) severity in infants with congenital heart disease: manual volumetric lesion segmentation and an observational categorical scale. Volumetric classification is labor intensive and the categorical scale is quick but unreliable. We propose the quartered point system (QPS) as a novel, intuitive, time-efficient metric with high interrater agreement. METHODS: QPS is an observational scale that asks the rater to score MRIs on the basis of lesion size, number, and distribution. Pre- and postoperative brain MRIs were obtained on term congenital heart disease infants. Three independent observers scored PVL severity using all three methods: volumetric segmentation, categorical scale, and QPS. RESULTS: One-hundred and thirty-five MRIs were obtained from 72 infants; PVL was seen in 48 MRIs. Volumetric measurements among the three raters were highly concordant (ρc = 0.94-0.96). Categorical scale severity scores were in poor agreement between observers (κ = 0.17) and fair agreement with volumetrically determined severity (κ = 0.26). QPS scores were in very good agreement between observers (κ = 0.82) and with volumetric severity (κ = 0.81). CONCLUSION: QPS minimizes training and sophisticated radiologic analysis and increases interrater reliability. QPS offers greater sensitivity to stratify PVL severity and has the potential to more accurately correlate with neurodevelopmental outcomes.

The whole spectrum of cystic periventricular leukomalacia of the preterm infant: results from a large consecutive case series.

PURPOSE: The purpose of this study is to describe features of cystic periventricular leukomalacia (PVL) in a large consecutive cohort study including long-term neurodevelopmental follow-up. METHODS: We performed a retrospective single-centre cohort study including all preterm infants ≤35 weeks of gestational age with PVL diagnosed by ultrasound scans (US) from a tertiary care university hospital between 1988 and 2012. RESULTS: The majority of 160 consecutively diagnosed cases had a gestational age between 28 and 32 weeks (60.6%), and male sex was predominant (60.6%). The most common associated clinical findings included respiratory distress syndrome, preterm premature rupture of the membranes, and chorioamnionitis (57.5, 49.4, and 39.4%, respectively). Infants presented with apnoeas in 66.3 and neonatal seizures in 23.1%. Any kind of respiratory support was present in 75.0%. Associated low-grade intraventricular haemorrhage was evident in 33.1, high-grade haemorrhage in 9.4%. Cysts were located on both hemispheres in 75% and PVL grades 3 and 4 were predominant (75.6%). Neurodevelopmental follow-up of 146 cases at a median age of 72 months revealed normal development in 11.0, mental retardation in 50.0, and cerebral palsy in 83.6%. Visual impairment was diagnosed in 21.9% and hearing impairment in one case. A quarter of cases (27.4%) developed seizure disorders. Outcome data were significantly better in unilateral compared to bilateral PVL. CONCLUSIONS: Long-term neurodevelopmental outcome of bilateral PVL always was adverse and different from unilateral PVL. The latter might be negatively influenced by associated intra- and periventricular haemorrhages.

Screening Cranial Imaging at Multiple Time Points Improves Cystic Periventricular Leukomalacia Detection.

OBJECTIVE: The aim of this study is to determine whether the cystic periventricular leukomalacia (cPVL) detection rate differs between imaging studies performed at different time points. DESIGN: We retrospectively reviewed the prospectively collected data of 31,708 infants from the NICHD Neonatal Research Network. Inclusion criteria were infants < 1,000 g birth weight or < 29 weeks' gestational age who had cranial imaging performed using both early criterion (cranial ultrasound [CUS] < 28 days chronological age) and late criterion (CUS, magnetic resonance imaging, or computed tomography closest to 36 weeks postmenstrual age [PMA]). We compared the frequency of cPVL diagnosed by early and late criteria. RESULTS: About 664 (5.2%) of the 12,739 infants who met inclusion criteria had cPVL using either early or late criteria; 569 using the late criterion, 250 using the early criterion, and 155 patients at both times. About 95 (14.3%) of 664 cPVL cases seen on early imaging were no longer visible on repeat screening closest to 36 weeks PMA. Such disappearance of cPVL was more common in infants < 26 weeks' gestation versus infants of 26 to 28 weeks' gestation (18.5 vs. 11.5%; p = 0.013). CONCLUSIONS: Cranial imaging at both < 28 days chronological age and closest to 36 weeks PMA improves cPVL detection, especially for more premature infants.

Relation between prognosis and changes of MBP and S100B in premature infants with periventricular leukomalacia.

This study aims to explore the relation between changes in myelin basic protein (MBP) and S100 protein (S100B) serum levels and prognosis in premature infants with periventricular leukomalacia (PVL). In our hospital, 78 premature infants with PVL and 43 normal premature infants were studied from July 1, 2007 to December 31, 2008. MBP and S100B serum levels were detected at 1, 3, 7, and 14 days after birth by using enzyme-linked immunosorbent assay. All infants were followed four times (once every 3 months) after discharge from hospital. Their intelligence quotient and physical development index were tested by using Gesell developmental scales. The MBP serum levels were significantly higher in premature infants with PVL at any time point than in normal premature infants. S100B serum levels gradually increased at 1, 3, and 7 days; peaked on the 7th day; and then gradually decreased to the normal level on the 14th day. The intelligence quatient and physical development index of infants with increased S100B and MBP levels on the 7th day were lower than those of infants who had normal S100B and MBP levels and those of normal premature infants. A negative relation exists between S100B and MBP serum levels and prognosis in PVL infants. An increase of MBP and S100B levels lasting >7 days could cause poor prognosis.

Compound heterozygous mutations in glycyl-tRNA synthetase are a proposed cause of systemic mitochondrial disease.

BACKGROUND: Glycyl-tRNA synthetase (GARS) is an aminoacyl-tRNA synthetase (ARS) that links the amino acid glycine to its corresponding tRNA prior to protein translation and is one of three bifunctional ARS that are active within both the cytoplasm and mitochondria. Dominant mutations in GARS cause rare forms of Charcot-Marie-Tooth disease and distal spinal muscular atrophy. CASE PRESENTATION: We report a 12-year old girl who presented with clinical and biochemical features of a systemic mitochondrial disease including exercise-induced myalgia, non-compaction cardiomyopathy, persistent elevation of blood lactate and alanine and MRI evidence of mild periventricular leukomalacia. Using exome sequencing she was found to harbor compound heterozygous mutations within the glycyl-tRNA synthetase (GARS) gene; c.1904C > T; p.Ser635Leu and c.1787G > A; p.Arg596Gln. Each mutation occurred at a highly conserved site within the anticodon binding domain. CONCLUSION: Our findings suggest that recessive mutations in GARS may cause systemic mitochondrial disease. This phenotype is distinct from patients with previously reported dominant mutations in this gene, thereby expanding the spectrum of disease associated with GARS dysregulation.

Neuroimaging and neurodevelopmental outcome of preterm infants with a periventricular haemorrhagic infarction located in the temporal or frontal lobe.

AIM: The aim of the study was to compare clinical and neuroimaging characteristics and neurodevelopmental outcome in preterm infants with a periventricular haemorrhagic infarction (PVHI) located in the temporal or frontal periventricular white matter. METHOD: The study was a retrospective hospital-based study of preterm infants with a frontal PVHI (n=21; 11 males, 10 females; mean birthweight 1527g; mean gestational age 30.3wks) or temporal PVHI (n=13; five males, eight females; mean birthweight 1205g; mean gestational age 30.2wks) admitted to the neonatal intensive care unit between 1990 and 2012. The clinical course, results of neuroimaging studies, and neurodevelopmental outcomes of preterm infants with a gestational age less than 34 weeks with a confirmed PVHI on early cranial ultrasonography and/or magnetic resonance imaging were reviewed. For assessment of neurodevelopmental outcome we used the Griffiths Mental Development Scales, the Movement Assessment Battery for Children, the Gross Motor Function Classification System, the Wechsler Preschool and Primary Scale of Intelligence, the Child Behavior Checklist, and ophthalmological assessment. An unfavourable neurodevelopmental outcome was defined as moderately or severely atypical neurological examination during the last visit: presence of cerebral palsy, epilepsy, a hearing or visual impairment, and/or atypical cognitive development (Griffiths Mental Development Scales developmental quotient or Wechsler Preschool and Primary Scale of Intelligence <85). RESULTS: Unfavourable outcome was observed in 12 out of 13 children with a temporal PVHI compared with six out of 21 children with a frontal PVHI (p=0.002). Only one of the included infants with a PVHI in the temporal white matter developed cerebral palsy, which was due to a parietal PVHI in the contralateral hemisphere. Cognitive impairment was noted in seven infants with a frontal PVHI and five with a temporal PVHI. There were more infants with a temporal PVHI who developed visual impairment (n=5) or behavioural problems (n=7) compared with those with a frontal PVHI (visual impairment (n=2), behavioural problems (n=3). INTERPRETATION: PVHI located in the temporal or frontal lobe is almost invariably related to a typical motor outcome, but carries a risk of cognitive, behavioural, and visual problems, especially in infants with a PVHI located in the temporal lobe.

Patterns of increases in interleukin-6 and C-reactive protein as predictors for white matter injury in preterm infants.

BACKGROUND: The aim of this study was to determine whether patterns of increases in serum interleukin-6 (IL-6) and C-reactive protein (CRP) levels at birth were associated with the development of white matter injury (WMI) in preterm infants with a fetal inflammatory response (FIR). METHODS: One hundred infants who were born at <32 weeks gestation and had funisitis, as determined by histological evidence of FIR, were studied. Infants were divided into four groups according to IL-6 and CRP levels at birth, with cut-off values of 200 pg/mL and 0.4 mg/dL, respectively. We compared the incidence of WMI, determined by MRI at term-equivalent age, among these groups. RESULTS: The number of infants in each group was 12, 43, 0, and 45 in the high IL-6 and high CRP (HH) group, high IL-6 and low CRP (HL) group, low IL-6 and high CRP (LH) group, and low IL-6 and low CRP (LL) group, respectively. The incidence of WMI was significantly higher in the HH group than in the HL group and LL group (83%, 40%, and 34%, respectively). Multiple logistic regression analysis revealed that a combined elevation in IL-6 and CRP levels was an independent predictor for the development of WMI (odds ratio, 8.3). CONCLUSION: A combined elevation in serum IL-6 and CRP levels at birth was associated with the development of WMI in preterm infants with FIR.

The spectrum of cerebral visual impairment as a sequel to premature birth: an overview.

PURPOSE: In children born prematurely, impairment of vision due to damage to the brain is more common than due to retinopathy of prematurity. Yet, the diagnosis of cerebral visual impairment may be missed. The subject of cerebral visual impairment in children is reviewed in order to explain and draw attention to the types of visual deficits and behaviours that may result as a sequel to premature birth. METHODS: A wide range of sources of data has been employed to assemble this overview. The principal reference source is PubMed. RESULTS: The material presented highlights the origin and range of visual deficits that result from damage to the brain, related to premature birth. Deficits of primary visual functions, perceptual dysfunction, simultanagnostic visual disorders and impaired visual guidance of movement (optic ataxia), as well as disorders of visual attention and memory, can occur in a variety of combinations and degrees. The resulting behavioural outcomes are described. CONCLUSION: Identification and characterisation of impaired vision, due to prematurity associated damage to the brain, are essential. This is required so as to ensure that affected children are not inappropriately disadvantaged on account of the diagnosis being missed or inadequately acted upon, but instead, they are managed optimally, both at home and at school, so that their development is enhanced to the greatest advantage.

Visual function in preterm infants: visualizing the brain to improve prognosis.

Considerable development of the visual system occurs in the third trimester of life, a time when very preterm-born infants are in a neonatal intensive care unit (NICU). Their very early birth during a period of rapid and marked neurodevelopment and their clinical course makes them a very high-risk population. A range of different events impacts brain development and the visual system, leading to significant long-term visual dysfunction. Improved neuroimaging techniques provide an important window on the early brain and visual system development of these vulnerable infants. Greater understanding of the etiology of visual impairment subsequent to preterm birth and the timing of critical processes will allow early recognition and the earlier implementations of interventions. In the longer term, this will help clinicians optimize NICU practice to reduce the incidence of visual dysfunction in these children.

Severe brain damage in premature infants associated with postnatal infection.

AIM: This study examined clinical features and neuroimaging characteristics of severe brain damage in premature infants with postnatal infection. METHODS: We retrospectively analyzed clinical data of two preterm infants who developed extensive encephalomalacia secondary to postnatal infection. RESULTS: Two premature boys experienced serious postnatal infection at about 3 weeks after birth; the infection was characterized by lethargy, apnea, increased CRP, severe bilateral pneumonia, positive sputum culture for multidrug-resistant bacteria, and mild changes of cerebrospinal fluid. Both infants required ventilation and antibiotic therapy. While both infants survived, a very extensive encephalomalacia was documented by serial cranial ultrasound, MRI and CT scans 3 to 4 weeks after postnatal infection. Their mothers had no premature ruptures of membranes and no signs of antenatal infection, suggesting potential postnatal infection in the infants. CONCLUSION: More studies are needed to better understand the underlying mechanism of encephalomalacia associated with postnatal infection. To facilitate early diagnosis and effective treatment, cranial ultrasound scans should be done routinely in premature infants with serious postnatal infection.

[The relationship between the severity of periventricular leukomalacia and the fractional anisotropy values of diffusion tensor imaging].

OBJECTIVE: We performed diffusion tensor imaging (DTI) in children with periventricular leukomalacia (PVL) to quantify the relationship between the fractional anisotropy (FA) values of DTI and the severity of PVL. METHODS: In this study, we performed DTI in 16 children (seven males, nine females) with PVL. To evaluate the FA values, we used region-of-interest (ROI) measurements and tractography-based measurements. We classified the patients into two groups based on the severity of the magnetic resonance imaging (MRI) findings: the mild group had white matter injury limited to a triangular zone around the lateral ventricle (n = 9) and the severe group had it extended forward (n = 7). Then, we performed ROI measurements for these two groups to evaluate the FA values. We also divided the patients into two groups based on their motor ability :those that could (n = 10) and could not (n = 6) stand. We used tractography-based measurements to evaluate the FA values. To reduce the bias caused by age, we divided the patients into two groups: those younger than 3 years and those 3 years of age and older. All data were analyzed using the Mann-Whitney U-test, and p < 0.05 was considered statistically significant. RESULTS: In the ROI measurements, regardless of age, the severe group showed a more significant FA reduction in the white matter of the parietal and occipital lobes, including the middle/posterior part of the centrum ovale, superior longitudinal fasciculus, arcuate fascicullus, and thalamic radiation. In the tractography-based measurements, regardless of age, the measured FA values were significantly lower in the group that could not stand. CONCLUSIONS: This study suggested that the measured FA values could be used to evaluate the severity of PVL quantitatively, and that DTI provides much more information for understanding the pathophysiology of PVL, as compared with conventional MRI.

[Pathomorphology of periventricular leukomalacia and other white matter lesions in infants].

The paper describes white matter lesions that differ from periventricular leukomalacia (PVL), such as diffuse leukomalacia (DL) and telencephalic gliosis (TG). There are three types of cerebral leukomalacias: PVL, DL, and subcortical leukomalacia. The morphological differences between PVL and DL are considered. The diffuse form of PVL is described. It is pointed out that colliquation PVL foci frequently occur in infants with birth weight less than 1500 g. There are data on the morphology of TG in which generalized and occasionally large-focal astrogliosis develops in the cerebral hemispheric white matter. It is suggested that it is inexpedient to identify the focal and diffuse components of PVL. The immunihistochemical findings led to the conclusion that PVL, DL, and TG did not result from the direct effects of pathogens of inherited infections on brain tissue.