Periventricular infarction diagnosed by ultrasound: a postmortem correlation

Assessment of risk factors for cystic periventricular leukomalacia

AIM

Periventricular leukomalacia (PVL) is an important cause of cerebral palsy in premature infants, and cystic PVL is the most serious form of the disease. The risk factors for cystic PVL in singleton fetuses at a gestational age of <35 weeks are unclear.

METHODS

This study included 2013 singleton birth infants delivered at a gestational age of <35 weeks in Kagoshima City Hospital between 2006 and 2017. The findings for 30 infants with cystic PVL were compared with those for 63 matched control infants by gestational age and birth weight.

RESULTS

The cystic PVL was associated with increased incidence of recurrent late deceleration (L/D) (43.4% vs. 15.9%, P = 0.004) and loss of variability (LOV) (10.0% vs. 0.0%, P = 0.03) in fetal heart rate monitoring and late-onset circulatory dysfunction (LCD) (33.3% vs. 11.1%, P = 0.02). Logistic regression analysis revealed that recurrent L/D (odds ratio [OR] = 3.57, 95% confidence interval [CI]: 1.29-10.15, P = 0.01) and LCD (OR = 3.41, 95% CI: 1.09-11.04, P = 0.03) were risk factors associated with cystic PVL. LOV was not included in the multivariate analysis as there were too few cases in both the cystic PVL and control groups.

CONCLUSION

Recurrent L/D, LOV and LCD are strongly associated with cystic PVL. In cases of fetal acidosis related to recurrent L/D or loss of variability, cystic PVL may occur.

Feasibility of combining two individualized lung recruitment maneuvers at birth for very low gestational age infants: a retrospective cohort study

Background

Lung recruitment at birth has been advocated as an effective method of improving the respiratory transition at birth. Sustained inflations (SI) and dynamic positive end-expiratory pressure (PEEP) were assessed in clinical and animal studies to define the optimal level. Our working hypothesis was that very low gestational age infants (VLGAI) < 32 weeks’ gestation require an individualized lung recruitment based on combining both manoeuvers.

Methods

Between 2014 and 2016, 91 and 72 inborn VLGAI, requiring a respiratory support beyond a continuous positive airway pressure (CPAP) = 5 cmH2O, were enrolled before and after introducing these manoeuvers based on progressive increase in SI up to 15 s, with simultaneous gradual increase in PEEP up to 15 cmH2O, according to the cardiorespiratory response. Retrospective comparisons of the incidence of mechanical ventilation (MV) < 72 h of life, short-term and before discharge morbidity were then performed.

Results

Among extremely low gestational age infants (ELGAI) < 29 weeks’ gestation, the following outcomes decreased significantly: intubation (90 to 55%) and surfactant administration (54 to 12%) in the delivery room, MV (92 to 71%) and its mean duration < 72 h of life (45 h to 13 h), administration of a 2nd dose of surfactant (35 to 12%) and postnatal corticosteroids (52 to 19%), and the rate of bronchopulmonary dysplasia (23 to 5%). Among VLGAI, all of these results were also significant. Neonatal mortality and morbidity were not different.

Conclusions

In our setting, combining two individualized lung recruitment maneuvers at birth was feasible and may be beneficial on short-term and before discharge pulmonary outcomes. A randomized controlled trial is needed to confirm these results.

The role of systemic hemodynamic disturbances in prematurity-related brain injury

Premature infants who experience cerebrovascular injury frequently have acute and long-term neurologic complications. In this article, we explore the relationship between systemic hemodynamic insults and brain injury in this patient population and the mechanisms that might be at play.

Elevated cerebral pressure passivity is associated with prematurity-related intracranial hemorrhage

OBJECTIVES

Cerebral pressure passivity is common in sick premature infants and may predispose to germinal matrix/intraventricular hemorrhage (GM/IVH), a lesion with potentially serious consequences. We studied the association between the magnitude of cerebral pressure passivity and GM/IVH.

PATIENTS AND METHODS

We enrolled infants <32 weeks' gestational age with indwelling mean arterial pressure (MAP) monitoring and excluded infants with known congenital syndromes or antenatal brain injury. We recorded continuous MAP and cerebral near-infrared spectroscopy hemoglobin difference (HbD) signals at 2 Hz for up to 12 hours/day and up to 5 days. Coherence and transfer function analysis between MAP and HbD signals was performed in 3 frequency bands (0.05-0.25, 0.25-0.5, and 0.5-1.0 Hz). Using MAP-HbD gain and clinical variables (including chorioamnionitis, Apgar scores, gestational age, birth weight, neonatal sepsis, and Score for Neonatal Acute Physiology II), we built a logistic regression model that best predicts cranial ultrasound abnormalities.

RESULTS

In 88 infants (median gestational age: 26 weeks [range 23-30 weeks]), early cranial ultrasound showed GM/IVH in 31 (37%) and parenchymal echodensities in 10 (12%) infants; late cranial ultrasound showed parenchymal abnormalities in 19 (30%) infants. Low-frequency MAP-HbD gain (highest quartile mean) was significantly associated with early GM/IVH but not other ultrasound findings. The most parsimonious model associated with early GM/IVH included only gestational age and MAP-HbD gain.

CONCLUSIONS

This novel cerebrovascular monitoring technique allows quantification of cerebral pressure passivity as MAP-HbD gain in premature infants. High MAP-HbD gain is significantly associated with GM/IVH. Precise temporal and causal relationship between MAP-HbD gain and GM/IVH awaits further study.

Neonatal cranial ultrasound lesions and developmental delays at 2 years of age among extremely low gestational age children

BACKGROUND

Studies of the relationship between ultrasound images from preterm newborns and developmental delay most often are based on small samples defined by birth weight and exclude infants not testable with standardized assessments.

METHODS

We evaluated associations between ultrasound-defined lesions of the brain and developmental delays at 24 months' corrected age in 1017 children born before the 28th postmenstrual week. Brain ultrasound scans were read for concordance on 4 lesions: intraventricular hemorrhage, moderate/severe ventriculomegaly, white matter echodense/hyperechoic lesions, and white matter echodense/hypoechoic lesions and 2 diagnoses-periventricular leukomalacia and periventricular hemorrhagic infarction. Certified examiners, who were not aware of the infants' ultrasound findings, administered the Bayley Scales of Infant Development-Second Edition. Children with an impairment (eg., blindness) that precluded testing with the Bayley Scales and those for whom >2 test items were omitted were classified using the Vineland Adaptive Behavior Scales Motor Skills Domain instead of the Psychomotor Development Index and the Adaptive Behavior Composite instead of the Mental Development Index.

RESULTS

Fully 26% of all of the children had delayed mental development (ie, Mental Development Index < 70), and 31% had delayed psychomotor development (ie, Psychomotor Development Index < 70). Ultrasound abnormalities were more strongly associated with low Psychomotor Development Index than with low Mental Development Index. Children without cranial ultrasound abnormality had the lowest probability (23% and 26%) of delayed mental or psychomotor development. Moderate/severe ventriculomegaly was associated with a more than fourfold increase in the risk of psychomotor delay and an almost threefold increase in the risk of mental delay. Echolucency was the next best predictor of delayed mental and psychomotor development. The probability of low scores varied with the number of zones involved and with the location of echolucency. At particularly high risk were infants with bilateral cerebellar hemorrhage, co-occurring ventriculomegaly and echolucency bilateral echolucency, or echolucency located posteriorly.

CONCLUSIONS

Focal white matter damage, as characterized by echolucent/hypoechoic lesion, and diffuse damage, as suggested by late ventriculomegaly, are associated with delayed mental and psychomotor development.

Oxygenation and ventilation in spontaneously breathing very preterm infants with nasopharyngeal CPAP in the delivery room

AIM

To provide data on ventilation, oxygenation and acid-base state from birth to 48 h in very preterm infants treated with lung recruitment manoeuvre and nasopharyngeal continuous positive airway pressure in the delivery room.

METHODS

Subjects of this prospective observational cohort study were 48 of 61 infants enrolled in a randomised controlled trial to test two lung recruitment manoeuvres after birth. The infants had received an arterial line in the delivery room. The outcome measures were data on oxygenation, ventilation and acid-base state during spontaneous breathing.

RESULTS

Data are presented as (n [%]; median [minimum-maximum]). 22 of 48 (46%) infants (gestational age, 26.4 [25.0-28.9] weeks; birth weight 870 [540-1310] g) were never intubated during the study. The FiO(2) of these infants was low (0.4 [0.21-0.45] at 45 min and 0.21 [0.21-0.5] at 48 h). PCO(2) reached its maximum at 24 (11-44) min (8 [6.4-10.8] kPa) and decreased below 6.7 kPa (median) within 3 h. The incidence of intracranial haemorrhage/periventricular leukomalacia did not increase with hypercapnia (pCO(2) > 8 kPa).

CONCLUSION

A transient period of hypercapnia after birth may occur in spontaneously breathing very preterm infants supported with nasopharyngeal continuous positive airway pressure in the delivery room. The incidence of cerebral damage was not increased in infants with hypercapnia.

Ultrasonographic features and severity scoring of periventricular hemorrhagic infarction in relation to risk factors and outcome

OBJECTIVE

Early diagnosis of periventricular hemorrhagic infarction in premature infants is based on bedside neonatal cranial ultrasonography. Currently, evaluation of its morphology and evolution by cranial ultrasound relies largely on data predating major advances in perinatal care and lacks a consistent classification system for determining severity of injury. The objective of this study was to examine the ultrasonographic morphology and evolution of periventricular hemorrhagic infarction in the modern NICU and to determine the value of a cranial ultrasonography-based severity score for predicting outcome.

METHODS

We retrospectively evaluated all cranial ultrasounds and medical records of 58 premature infants with periventricular hemorrhagic infarction. We assigned each subject a severity score based on extent of echodensity, unilateral versus bilateral, and presence or absence of midline shift. A neurologic examination was performed after 12 months adjusted age.

RESULTS

The parenchymal echodensity of periventricular hemorrhagic infarction most often involved parietal and frontal territories and evolved into single and/or multiple cysts. One quarter of cases were bilateral, and nearly 70% were extensive. Higher severity scores were significantly associated with pulmonary hemorrhage and low bicarbonate levels and with outcomes of fatality, early neonatal seizures, and motor disability.

CONCLUSIONS

Despite advances in perinatal medicine, periventricular hemorrhagic infarction remains an important complication of prematurity. Periventricular hemorrhagic infarction can be graded using a scoring system based on sonographic characteristics. Higher severity scores predict worse outcome. Such severity scoring could improve the clinician's ability to counsel parents regarding management decisions and early intervention strategies.

Hemodynamics of the cerebral arteries of infants with periventricular leukomalacia

OBJECTIVE

This study investigated the developmental changes in blood flow in each cerebral artery among infants with and without periventricular leukomalacia (PVL), to elucidate the time of onset of PVL.

METHODS

Eight of 67 low birth weight infants were diagnosed through ultrasonography as having PVL with cyst formation. The mean cerebral blood flow velocities (CBFVs) in the anterior cerebral artery, middle cerebral arteries (MCAs), posterior cerebral arteries (PCAs), internal carotid arteries (ICAs), and basilar artery were measured with Doppler ultrasonography at postnatal days 0, 1, 2, 3, 4, 5, 7, 10, 14, 21, 28, 42, 56, and 70. Four of 8 infants with cyst formation and 1 of 59 infants without cyst formation developed cerebral palsy.

RESULTS

The mean CBFVs of infants with PVL were significantly lower in the anterior cerebral artery (days 14-70), the right MCA (days 14-70), the left MCA (days 14-70), the right PCA (days 7-70), the left PCA (days 5-70), the right ICA (days 7-70), the left ICA (days 7-70), and the basilar artery (days 14 and 28-70). The CBFVs in all arteries were also lower among those with PVL than among intact infants on day 0. The CBFVs increased postnatally in the PCAs of infants with intact brains, whereas they remained unchanged after day 14 or 21 among infants with PVL. There was a significant difference in the prevalence of cerebral palsy between the 2 groups.

CONCLUSIONS

We suggest that the total cerebral blood supply is decreased in cases of cystic PVL and that this reduction occurs just after birth, in a defined sequence, in the cerebral arteries. We conclude that the insult resulting in PVL might occur close to the time of birth.

Sustained pressure-controlled inflation or intermittent mandatory ventilation in preterm infants in the delivery room? A randomized, controlled trial on initial respiratory support via nasopharyngeal tube

AIM

To prove the hypothesis that sustained pressure-controlled inflation compared to intermittent mandatory ventilation for lung recruitment via nasopharyngeal tube after delivery is more effective in reducing the rate of endotracheal intubation and mechanical ventilation in very preterm infants.

METHODS

The study was designed as a randomized, controlled trial. The setting was the delivery room and neonatal intensive care unit of a university hospital in Germany. Subjects were 61 infants (25.0-28.9 wk of gestation) with signs of respiratory distress immediately after birth. The infants were randomized in the delivery room to two different respiratory interventions: either to sustained pressure-controlled inflation (15 s) or to intermittent mandatory ventilation (rate 60 min(-1)). This respiratory support was given by a nasopharyngeal tube. The inflation pressure or peak inspiratory pressure was increased stepwise (20-25-30 cm H2O) according to the response of heart rate and oxygenation.

RESULTS

The main outcome measure was treatment failure, i.e., endotracheal intubation and mechanical ventilation according to given intubation criteria. Treatment failure occurred in 61% (95% CI, sustained pressure-controlled inflation: 42-78) and 70% (95% CI, intermittent mandatory ventilation: 51-85) (p = 0.59). The rates of mortality (3/61), severe intraventricular haemorrhage (5/61) and chronic lung disease (10/58) were not different between groups.

CONCLUSION

Sufficient spontaneous breathing within the first 48 h of life without endotracheal intubation and mechanical ventilation was achieved in about 30% with both methods of initial respiratory support.

Preterm children have disturbances of white matter at 11 years of age as shown by diffusion tensor imaging

Preterm birth frequently involves white matter injury and affects long-term neurologic and cognitive outcomes. Diffusion tensor imaging has been used to show that the white matter microstructure of newborn, preterm children is compromised in a regionally specific manner. However, until now it was not clear whether these lesions would persist and be detectible on long-term follow-up. Hence, we collected diffusion tensor imaging data on a 1.5-T scanner, and computed fractional anisotropy and coherence measures to compare the white matter integrity of children born preterm to that of control subjects. The subjects for the preterm group (10.9 +/- 0.29 y; n = 9; birth weight <or= 1500 g; mean gestational age, 28.6 +/- 1.05 wk) possessed attention deficits, a common problem in preterms. They were compared with age- and sex-matched control children (10.8 +/- 0.33 y; n = 10; birth weight >or= 2500; gestational age, >or= 37 wk). We found that the preterm group had lower fractional anisotropy values in the posterior corpus callosum and bilaterally in the internal capsules. In the posterior corpus callosum this difference in fractional anisotropy values may partially be related to a difference in white matter volume between the groups. An analysis of the coherence measure failed to indicate a group difference in the axonal organization. These results are in agreement with previous diffusion tensor imaging findings in newborn preterm children, and indicate that ex-preterm children with attention deficits have white matter disturbances that are not compensated for or repaired before 11 y of age.

Cerebral morbidity in preterm twins

BACKGROUND

Whether twins are more prone to increased neonatal morbidity than singletons remains controversial. It was the aim of this study to define the special risks of preterm twins with an emphasis on cerebral morbidity.

METHODS

A retrospective chart review was carried out of all consecutively born twins (n = 230) and the corresponding sets of singletons of a single level-III neonatal intensive care unit. The subjects had a gestational age between 24 and 37 weeks, and were born in 1990-98.

RESULTS

Twin pregnancies were more often complicated by preterm contractions (odds ratio (OR) 4.03 (95% confidence interval (CI) 2.39, 6.78)) whereas gestosis was significantly less (OR 0.14 (95% CI 0.05, 0.41)). Grades III and IV intracranial bleeding occurred significantly more often in twins compared to singletons (OR 3.75 (95% CI 1.65, 8.97)), with infants of less than 32 weeks' gestational age being predominantly affected (OR 3.31 (95% CI 1.33, 8.29)). Infants of less than 32 weeks' gestational age developed respiratory distress syndrome more often than the corresponding singletons (OR 1.93 (95% CI 1.15, 3.25)). There were no differences in all observed items between the first- and second-born twins.

CONCLUSION

Twins of less than 37 weeks' gestational age were significantly more often affected by high-grade intraventricular hemorrhage irrespective of birth order. Periventricular leukomalacia occurred twice as often as in singletons. There were no differences with respect to mortality and further morbidity except for respiratory distress syndrome in preterm twins of less than 32 weeks' gestational age.

Acute respiratory failure and short-term outcome after premature rupture of the membranes and oligohydramnios before 20 weeks of gestation

OBJECTIVES

To study the effect of premature rupture of membranes and oligohydramnios before 20 weeks of gestation (PROM20) on acute respiratory morbidity and on short-term outcome in infants with a gestational age >or=24 weeks.

STUDY DESIGN

A historic cohort study was performed of all infants born after PROM20 with a gestational age greater-than-or-equal24 weeks between 1990 and 1999. Control infants were matched for year of birth, gestational age, and birth weight.

RESULTS

PROM20 infants had an increased acute respiratory morbidity (higher ventilator settings and increased incidence of hypoxemia, hypercapnia, and pulmonary hypertension) and a trend to more air leaks. Although not statistically different, PROM20 infants had more complications (neonatal survival, 68% vs 95%; severe intracranial hemorrhage, 31% vs 6%; chronic lung disease in surviving infants, 46% vs 17%). The relative risk for combined morbidity (death, intracranial hemorrhage, chronic lung disease) was increased (3.0, P =.019) when compared with matched control infants. However, 31% of the surviving PROM20 infants were discharged without apparent morbidity.

CONCLUSIONS

Expectant treatment in women with PROM20 and present neonatal intensive care has improved the survival of PROM20 infants despite severe initial respiratory failure. However, chronic morbidity still occurred.

Topography of cerebral white-matter disease of prematurity studied prospectively in 1607 very-low-birthweight infants

The objective of this study was to evaluate to what extent (1) the characteristics of localization, distribution, and size of echodense and echolucent abnormalities enable individuals to be designated as having either periventricular hemorrhagic infarction or periventricular leukomalacia and (2) the characteristics of periventricular hemorrhagic infarction and periventricular leukomalacia are independent occurrences. The population for this study consisted of 1607 infants with birthweights of 500 to 1500 g, born between January 1991 and December 1993, who had at least one cranial ultrasound scan read independently by at least two ultrasonographers. The ultrasound data collection form diagrammed six standard coronal views. The cerebrum was divided into 17 zones in each hemisphere. All abnormalities were described as being echodense or echolucent and were classified on the basis of their size, laterality, location, and evolution. Eight percent (134/1607) of infants had at least one white-matter abnormality. The prevalence of white-matter disease decreased with increasing gestational age. Most abnormalities were small or medium sized and unilateral; only large echodensities tended to be bilateral and asymmetric. Large abnormalities, whether echodense or echolucent, were more likely than smaller abnormalities to be widespread, and the extent of cerebral involvement was independent of whether abnormalities were unilateral or bilateral. Large abnormalities were relatively more likely than small abnormalities to involve anterior planes. Small abnormalities, whether echodense or echolucent, or whether unilateral or bilateral, preferentially occurred near the trigone. Using the characteristics of location, size, and laterality/symmetry, we were able to allocate only 53% of infants with white-matter abnormalities to periventricular hemorrhagic infarction or periventricular leukomalacia. Assuming that periventricular leukomalacia and periventricular hemorrhagic infarction are independent and do not share risk factors, and that each occurs in approximately 5% of infants, we would have expected 0.25%, or about 4 individuals, to have abnormalities with characteristics of both periventricular leukomalacia and periventricular hemorrhagic infarction, whereas we found 63 such infants. Most infants with white-matter disease could not be clearly designated as having periventricular hemorrhagic infarction or periventricular leukomalacia only. Periventricular hemorrhagic infarction contributes to the risk of periventricular leukomalacia occurrence, or the two sorts of abnormalities share common risk antecedent factors. The descriptive term echodense or echolucent and the generic term white-matter disease of prematurity should be used instead of periventricular leukomalacia or periventricular hemorrhagic infarction when referring to sonographically defined white-matter abnormalities.

Can neurological injury be timed?

Our knowledge about the cause of cerebral palsy continues to expand and prenatal events are thought to play an important role. This article reviews laboratory tests, imaging studies and pathologic findings that have been used to identify the timing of neurological injury. Limitations exist for all modalities, however, imaging studies, electroencephalograms and pathologic examination provide the most useful information. Improvements in our ability to time neurological injury will better direct our efforts to prevent cerebral palsy.

Delivery room management of extremely low birth weight infants: spontaneous breathing or intubation?

OBJECTIVE

To study the effect of two different delivery room (DR) policies on the rate of endotracheal intubation and mechanical ventilation (EI/MV) and short term morbidity in extremely low birth weight infants (ELBWI; <1000 g, >/=24 weeks).

METHODS

Retrospective cohort study of 123 inborn ELBWIs born in 1994 and in 1996. DR policies have changed. Until 1994, ELBWIs were intubated immediately after delivery when presenting the slightest signs of respiratory distress or asphyxia after initial resuscitation using a face mask and a handbag. During 1995, the guidelines for respiratory support were changed. In 1996, continuous (15 to 20 seconds), pressure controlled (20 to 25 cm H2O) inflation of the lungs using a nasal pharyngeal tube, followed by continuous positive airway pressure (CPAP; 4 to 6 cm H2O) was applied to all ELBWIs immediately after delivery to establish a functional residual capacity and perhaps to avoid EI/MV. In addition to the changes in respiratory support, the prevention of conductive and evaporative heat loss was improved in 1996. For analysis of morbidity and mortality, infants were matched for gestational age and birth weight.

RESULTS

The rate of EI/MV in the DR decreased from 84% in 1994 to 40% in 1996. In 1996, 25% of the ELBWIs were never intubated (7% in 1994), but 35% of the ELBWIs needed secondary EI/MV, primarily because of respiratory distress syndrome (RDS). Initial ventilator settings, ventilator days, mortality, and morbidity were not different between ELBWIs with EI/MV in the DR and infants with secondary EI/MV attributable to RDS in the intensive care unit. ELBWIs with no EI/MV that was caused by RDS had a lower morbidity (ie, bronchopulmonary dysplasia, intraventricular hemorrhage >grade 2 and/or periventricular leukomalacia), mortality, and fewer hospital days (mean: 79 vs 105 days). The incidence of gastrointestinal adverse effects like feeding intolerance or necrotizing enterocolitis was not increased in 1996. PaCO2 was significantly higher at admission to the neonatal unit in ELBWIs with CPAP in 1996 (54 +/- 15 mm Hg, 7.2 +/- 2.0 kPa) compared with infants with EI/MV in 1994 (38 +/- 11 mm Hg, 5.1 +/- 1. 5 kPa. A total of 26% of spontaneously breathing infants had hypercapnia (PaCO2 >/=60 mm Hg [8.0 kPa]), compared with 7% of infants with EI/MV in 1994. Within the first few hours of life, PaCO2 decreased to 46 (32 to 57) mm Hg (6.1 [4.3 to 7.6] kPa) in never intubated ELBWIs (n = 17), but increased to 70 (57 to 81) mm Hg (9.3 [7.6 to 10.8] kPa) in ELBWIs (n = 14) with RDS and secondary EI/MV (age 5.5 [1 to 44] hours).

CONCLUSIONS

In our setting, the individualized intubation strategy in the DR restricted EI/MV to those ELBWIs who ultimately needed it, without increasing morbidity or mortality in infants with secondary EI/MV attributable to RDS. We speculate that an individualized intubation strategy of the ELBWI is superior to immediate intubation of all ELBWIs with slight signs of respiratory distress after birth.

Brain injury in the premature infant: overview of clinical aspects, neuropathology, and pathogenesis

Brain injury in the premature infant is an extremely important problem, in part because of the large absolute number of infants affected yearly. The two principal brain lesions that underlie the neurological manifestations subsequently observed in premature infants are periventricular hemorrhagic infarction and periventricular leukomalacia. The emphases of this article are the neurology, neuropathology, and pathogenesis of these two lesions. Recent work suggests that the ultimate goal, prevention of the lesions, is potentially achievable. Periventricular hemorrhagic infarction may be preventable by prevention of germinal matrix/intraventricular hemorrhage, and periventricular leukomalacia, by detection of impaired cerebrovascular autoregulation, prevention of impaired cerebral blood flow, and interruption of the cascade to oligodendroglial cell death by such agents as free-radical scavengers.

Brain injury in the premature infant--from pathogenesis to prevention

Brain injury in the premature infant is an extremely important problem, in part because of the large absolute number of infants affected yearly. The two principal brain lesions that underlie the neurological manifestations subsequently observed in premature infants are periventricular hemorrhagic infarction and periventricular leukomalacia. The emphases of this article are the neurology, neuropathology and pathogenesis of these two lesions. Recent work suggests that the ultimate goal, prevention of the lesions, is potentially achievable. Periventricular hemorrhagic infarction may be preventable by prevention of germinal matrix-intraventricular hemorrhage, and periventricular leukomalacia, by detection of impaired cerebrovascular autoregulation, prevention of impaired cerebral blood flow and interruption of the cascade to oligodendroglial cell death by such agents as free radical scavengers.

Sonographic diagnosis of intracranial hemorrhage and periventricular leukomalacia in premature African neonates

Transfontanelle ultrasound (US) was done prospectively and analyzed for intra-cranial hemorrhage (ICH) and periventricular leukomalacia (PVL) in 110 premature infants. The babies were divided into two subgroups according to their birth weights (BW): those with BW of 1500 g or less (n = 93) belonged to subgroup A while babies of BW between 1500 and 2500 g (n = 17) were placed in subgroup B. Overall incidence of ICH and PVL was 24.5 and 26.4%, respectively in the 110 cases studied. Under subgroup A, 26/93 (28.0%) cases had ICH while 22/93 (23.7%) cases had PVL. In subgroup B, 2/17 (11.8%) cases had ICH while PVL was noted in 7/17 (41.2%) cases. These results show that premature African children have a lower incidence of ICH but a higher incidence of PVL compared to babies from temperate regions. Genetic and environmental factors are probably responsible for these variations in the occurrence of both diseases in population groups from different geographical locations.

Diagnosis of intracranial lesions in very-low-birthweight infants by ultrasound: incidence and association with potential risk factors

This study was designed to determine the frequencies of germinal matrix and ventricular haemorrhages as well as lesions in the white matter diagnosed by ultrasonography. In subsequent studies the effects of perinatal brain lesions on the cognitive and motor development of preterm children will be presented. Lesions of the white matter are probably more damaging than intraventricular and subependymal bleeds. Therefore, a modified classification of the lesions was used, clearly separating bleeds from white matter pathology. The study includes 291 infants with a body weight of < or = 1500 g consecutively admitted to the neonatal intensive-case unit at Karolinska Hospital from 1988 to 1993. Fifty-four (18.9%) died before 6 months. Two hundred and sixty-three infants were examined using ultrasound. Pathology due to bleeding was classified into three grades (B1-3) similar to Papile's first three grades. Pathology in periventricular white matter was classified into four groups (W1-4): W1 = subtle and We = distinctive white matter echodensities; W3 = cyst formation; W4 = large, intense echodensity. Forty-nine patients had abnormalities in the periventricular white matter (15 W1, 12 W2, 11 W3 and 11 W4) and 58 had subependymal (B1 = 29) or ventricular bleeding without (B2 = 13) or with dilatation (B3 = 16). Ventilator treatment was significantly associated with both B and W lesions. Low gestational age, low birthweight, small for gestational age, pre-eclampsia and caesarean section were significantly associated with B lesions whereas asphyxia, surfactant treatment, male patient sex and outborn were associate with W lesions; b 1-3 and W 1-4 lesions were thus partly associated with different potential risk factors. The pre- and perinatal potential risk factors could only partly explain the variance in the frequency of B and W lesions, indicating that there are yet unidentified risk factors for intracranial ultrasonographic pathology.

Immunohistochemical study of myelination and oligodendrocyte in infants with periventricular leukomalacia

Eighteen patients with periventricular leukomalacia (PVL) of the focal or widespread type were immunohistochemically studied with respect to myelination and ferritin-containing oligodendrocytes and compared with 23 controls. Morphometric examination of myelination and ferritin-containing oligodendrocytes revealed normal development in the nonnecrotic cerebral white matter of the focal PVL brains. Myelination was mainly impaired in the necrotic or gliotic periventricular white matter of the widespread PVL brains. The expression of lipid components was poorer than that of myelin basic protein and the number of ferritin-containing oligodendrocytes was decreased in the necrotic or diffuse gliotic region of the widespread PVL brains compared to the controls. There was a significant relationship between the number of ferritin-containing oligodendrocytes and the degree of myelination. The impaired myelination in the PVL brains occurred in the necrotic as well as gliotic regions in the cerebral white matter, and may be related to the decrease of normal oligodendrocytes.

Clinical aspects of perinatal hypoxic-ischemic brain injury

Perinatal hypoxic-ischemic cerebral injury is a significant cause of neurological morbidity and mortality in childhood. It is often difficult to determine the precise timing of such injury. Data from epidemiological and neuropathological studies have identified several maternal and fetal risk factors that seem to be associated with suspected prenatal brain injury. Hypoxic-ischemic cerebral injury that originates earlier in gestation may result in few, if any, clinical abnormalities during the newborn period. Clinical abnormalities may also be difficult to recognize in the premature newborn, and greater reliance must be placed on other adjunctive investigations, eg, neuroimaging. In contrast, term infants who sustain acute, intrapartum hypoxic-ischemic insult of sufficient magnitude to result in long-term sequelae invariably show recognizable encephalopathy during the newborn period. A combination of clinical data and adjunctive investigations during the neonatal period is a powerful predictive tool for long-term outcome.

Assessment of local cerebral blood flow in neonates with N-isopropyl-P-[123I]iodoamphetamine and single photon emission computed tomography

Local cerebral blood flow was measured in 10 high-risk infants with neonatal episodic neurological events at 41-44 post-conceptional weeks using N-isopropyl-p-[123I]iodoamphetamine (IMP) and single photon emission computed tomography (SPECT). In 5 of the 7 infants with normal neurological outcome, prominent cerebral perfusion was found in the basal ganglia, brainstem, cerebellum, parietal white matter, and sensory motor cortex. The frontal lobes showed poor relative perfusion. In 3 infants with severe neurological deficits, SPECT demonstrated severe hypoperfusion of all parts of the brain except the basal ganglia, brainstem and sensorimotor cortex. However, MRI revealed non-specific changes, such as poor myelination and ventricular dilatation. SPECT, when performed in the first weeks of life, can be useful and may be more sensitive than MRI in predicting the occurrence of major neurological handicaps. However, because of the relatively invasive character and high cost of SPECT, SPECT should not necessarily be performed in all high-risk neonates.

A comparative magnetic resonance imaging study of the corpus callosum in neurologically normal children and children with spastic diplegia

To determine the extent of brain damage in children with spastic diplegia, we analyzed the true midsagittal magnetic resonance imaging findings for the corpus callosum in 43 children with spastic diplegia and in 69 neurologically normal children. In the normal children, the thicknesses of the genu, midbody, splenium and the entire corpus callosum were found to increase with age, while the ratios of the thickness of the splenium and of the midbody to the length were constant, regardless of age. Both ratios were significantly reduced in diplegic children and the ratio for the splenium was highly correlated with the extent of motor impairment. Assessment of the morphometric changes in the corpus callosum using magnetic resonance imaging may contribute to the determination of the extent of brain damage in diplegic children.

Developmental features of the brain in preterm and fullterm infants on MR imaging

Normal development and maturation in pre- and postnatal periods were studied using MR imaging. For this purpose, we performed MR imaging at a postmenstrual age of 37-44 weeks in both low-risk preterm and fullterm infants and assessed the myelination pattern and the dimension of the pituitary gland, corpus callosum, pons and cerebellar vermis. There were no differences in stages of myelination and the size of these structures in both groups. MR imaging was also performed in infants with various cerebral injuries. Focal or diffuse areas of hyperintensity on T2-weighted images and delayed myelination were the commonly observed abnormal findings in these infants.

Intraventricular Hemorrhage: An Update

Although the incidence of intraventricular hemorrhage (IVH) has decreased in recent years, the increasing survival rates for the smallest premature infants indicate that the lesion will continue to be a major problem in neonatal intensive care facilities. We review prenatal, perinatal, and postnatal variables that have been associated with enhanced risk of IVH and address some of the methodological limitations of previously reported studies. The neuropa-thology is characterized by bleeding into the subependymal germinal matrix, with subsequent rupture into the lateral ventricle. The pathogenesis of IVH relates to intravascular, vascular, and extravascular factors. Intravas-cular factors are those that relate primarily to control of blood flow and pressure in the microcirculation of the germinal matrix. Vascular factors relate to the microcirculation of the matrix, the site of initial bleeding. A maturation-dependent alteration of vascular integrity and a vulnerability of matrix vessels to injury appear important. Extravascular factors include those relevant to mesenchy-mal and glial support for matrix vessels and to local fibrino-lytic activity in the germinal matrix. Prognosis in the setting of IVH relates to the mechanisms of brain injury, the most important of which is pcriventricular hemorrhagic infarction, often inappropriately called grade IV IVH and often associated with subsequent motor and cognitive deficits. Prevention of IVH remains the most important goal. Prenatal interventions include prevention of premature birth, transportation of premature infants to a tertiary facility in utero rather than after birth, possibly prenatal administration of phenobarbital or vitamin K, and optimal management of labor and deliver. Postnatal interventions include careful newborn resuscitation, correction or prevention of major hemodynamic disturbances, and correction of abnormalities of coagulation. Postnatal pharmacological interventions that have been studied in detail include phenobarbital, indomethacin, ethamsylate, and vitamin E. No single agent among this group has been shown consistently to lead to a decrease in incidence and severity of IVH.

Natural history of ventricular dilatation in preterm infants: prognostic significance

Cerebral ultrasounds were prospectively performed in 100 infants weighing 1,500 gm or less in order to evaluate the prognostic significance of ventricular dilatations and their associated findings. There was no difference in the incidence of ventricular dilatation (24%) between patients with or without periventricular hemorrhage (PVH). Although patients with PVH developed ventricular dilatation significantly earlier than infants without PVH, no differences were observed in severity, location, head circumference growth, or intracranial pressure between the groups. Ventricular dilatation was statistically related to PVH grade III and PVH with parenchymal involvement; grades moderate-to-severe of periventricular echogenicity; and cystic periventricular leukomalacia (PVL). Ventricular dilatation persisted longer than 6 weeks in 61% of infants and had irregular margins in 62%. The latter were significantly related to cystic PVL. Seventy-seven of 100 infants examined were followed until 20 months corrected age. Ventricular dilatation mainly when persistent and with irregular margins was associated with handicaps. We conclude that ventricular dilatation is frequent in very low-birth weight infants. Furthermore, its occurrence may be independent of PVH. Persistent ventricular dilatation with irregular margins, even in its mild forms, suggests a parenchymal lesion and guarded prognosis.

Reliability of interpretation of cranial ultrasound examinations of very low-birthweight neonates

The authors studied intra- and inter-reader reliability of the interpretation of cranial ultrasound examinations of very low-birthweight infants. A radiologist read 173 films, 88 of which he had read previously; the other 85 had been read previously by a second radiologist. For the diagnoses of subependymal hemorrhage and intraventricular hemorrhage, intra-reader agreement was similar to inter-reader agreement. 98 ultrasound films were read initially as showing subependymal hemorrhage; in nine cases the second reading did not agree. In five of 58 cases read initially as showing intraventricular hemorrhage, the second reading did not agree. Similarly, of 32 cases read initially as showing intraparenchymal echo-density, four were interpreted as negative on second reading. For all three diagnoses, disagreement occurred often enough to cause substantial misclassification bias when cranial ultrasound is used for clinical research.

Cardiotocographic and sonographic findings in two cases of antenatally diagnosed intrauterine fetal brain death

Intrauterine fetal brain death is a rare cause of a fixed fetal heart rate pattern. Seven cases have been previously reported in the literature, but only two of them were diagnosed prenatally and all the newborns died soon after delivery. Two additional cases of antepartum diagnosis of intrauterine fetal brain death, managed expectantly, are reported. We had the unique opportunity to document progressive sonographic cerebral changes during the follow-up period, following the neurological event, while the fetus continued life and growth in utero. The cardiographic and sonographic findings suggesting intrauterine fetal brain death were a prolonged fixed fetal heart rate, even following a vibroacoustic and contraction stress test; an atonic fetus without breathing and body movement; and the appearance of hydramnios and the development of ventriculomegaly.

Postnatal encephaloclastic porencephaly--a new lesion?

A previously unrecognised and distinctive pattern of severe brain injury in extreme preterm neonates was observed recently. Fifteen neonates of birth weight 600-1270 g and gestation of 24-32 weeks showed relatively late development on cerebral ultrasound scan of extensive dense and cystic lesions involving the periphery of the brain. The extent of the changes was confirmed at postmortem examination in 11 babies. These changes have been called encephaloclastic porencephaly. The population of babies in whom this has occurred and their clinical outcome has been reviewed, with comparison between the evolution of the ultrasound changes and pathological findings at postmortem examination.

Ultrasonographic findings in thalamus and basal ganglia in term asphyxiated infants

Three severely asphyxiated term neonates demonstrated bilateral hyperechogenicity in the thalamus and basal ganglia. During evolution, areas of attenuated echogenicity appeared in these structures at the same time as periventricular cysts were evident in 2 patients with coexistent periventricular leukomalacia. All 3 patients developed ventricular dilatation; in the 2 patients with periventricular leukomalacia, the ventricular border was irregular in the outer (dorsal) margin, and interhemispheric fissures were widened as a manifestation of cerebral atrophy. Furthermore, the thalamic inner (ventral) margins of the lateral ventricles were irregular in all 3 patients. This previously unrecognized finding points to a particular form of cerebral atrophy localized in the gangliothalamic region that contributes to the development of ventriculomegaly. The reported sonographic sequence implies profound damage in the thalamus and basal ganglia in asphyxiated infants which undoubtedly has contributed to the poor outcomes of our patients.

White matter damage in preterm newborns--an epidemiologic perspective

Prior to 1980, white matter abnormalities of the preterm newborn were known exclusively as pathological entities, but now cranial ultrasonography can image white matter abnormalities in life. Ultrasonographic white matter echodensities and echolucencies in low birthweight babies predict later handicap (especially cerebral palsy) more accurately than any other antecedent. With the increased availability of high resolution cranial ultrasonography and the improved skill in obtaining and reading cranial ultrasonograms, rapid gains can be expected in our understanding of white matter disorders. These advances are likely to be made in the diagnosis and classification of white matter disorders and in their epidemiologic and prognostic features, topics explored in this review.

White matter necrosis in very low birth weight infants: neuropathologic and ultrasonographic findings in infants surviving six days or longer

We describe the neuropathologic and ultrasonographic findings in 22 very low birth weight infants (mean weight 948 gm) who survived at least 6 days and for whom cranial ultrasonography had been performed three or more times in life. White matter necrosis was found in 15 of the 22 subjects and was judged chronic (5 days' duration or longer) in seven subjects. The most common pattern was diffuse necrosis of hemispheric white matter, found in 10 of 15 infants; restriction of necrosis to the periventricular region was found in only three infants. The classic histologic features of periventricular leukomalacia were absent from 7 of the 15 infants with necrosis. Seventeen infants had intraventricular hemorrhage, but extension of ventricular blood into white matter unaffected by infarction was not found. Two ultrasonographic features were associated with white matter necrosis: increased parenchymal echogenicity and ventricular enlargement. One or both of these findings were present in 67% of infants with white matter necrosis, in 90% of infants with diffuse necrosis, but in no infant without necrosis. Increased parenchymal echogenicity was seen in all four infants with hemorrhagic necrosis, in 60% of infants with diffuse necrosis, but in none of the five infants with localized necrosis. We conclude that the very small infants now dying in nurseries have a form of white matter damage that is more extensive than, and in some cases histologically different from, periventricular leukomalacia as originally described. Ultrasonography as used in this study identified most but not all infants with pathologically verified white matter necrosis.

Antenatal origin of neurologic damage in newborn infants. II. Multiple gestations

Necrosis of the cerebral white matter may be identified in living infants with echoencephalography. Echoencephalographic studies were performed in 89 twins and 12 triplets at less than 36 weeks of gestation to determine the incidence and complications associated with antenatal necrosis of the cerebral white matter. Antenatal necrosis of the cerebral white matter was identified when brain atrophy or cavities in the white matter were present by day 3 of life. Fourteen infants (13.8%) were considered to have antenatal necrosis of the cerebral white matter. The incidence of antenatal necrosis of the cerebral white matter was higher in monochorionic than in dichorionic infants (30% vs 3.3%; p less than 0.001). Univariate analysis showed that antenatal necrosis of the cerebral white matter was significantly associated with polyhydramnios, intrauterine fetal death of the cotwin, hydrops, multiple placental vascular connections, and placental artery-to-artery, vein-to-vein, and artery-to-vein anastomosis. Logistic regression analysis showed that antenatal necrosis of the cerebral white matter was predicted by the presence of either artery-to-artery or vein-to-vein anastomosis and by intrauterine fetal death of a cotwin. Vein-to-vein anastomosis had the strongest association, because 89% of seven infants with vein-to-vein anastomosis demonstrated antenatal necrosis of the cerebral white matter (p = 0.003). Monochorionic multiple gestations frequently are complicated by antenatal necrosis of the cerebral white matter. Multiple vascular connections with vein-to-vein anastomosis appear as the most important associated factor for antenatal necrosis of the cerebral white matter in this population.

Periventricular leukomalacia: ultrasonic and neuropathological correlations

Ultrasound scans of a preterm neonate (27 weeks gestation) at seven weeks of age showed periventricular echo-free cavities, but these were no longer visible at 15 weeks, three weeks before the infant died. At autopsy, a linear glial scar, extending from the periventricular white-matter into the white axis of the parasagittal gyrus, was found in the area occupied by the periventricular cysts. The larger cavity was reduced to a slit-like excavation in the midst of glial tissue. Unsuspected focal infarcts in the cerebral cortex were also found. This observation demonstrates that transient echo-free cavities represent foci of cystic necrosis, which are subject to secondary collapse. In the authors' experience, the linear extension of periventricular leukomalacia (PVL) into the core of parasagittal gyri is a frequent feature of PVL, and one which cannot easily be accounted for by the usual explanations of border-zone ischaemic softening.

Neurosonographic features of periventricular echodensities associated with cerebral palsy in preterm infants

We studied the value of neonatal neurosonograms in preterm infants for predicting the development of cerebral palsy (CP). All infants born at less than 33 weeks of gestation who were admitted to the intensive care nursery of Thomas Jefferson University Hospital from 1982 to 1986 were serially studied with cranial ultrasound methods that reliably detect neonatal periventricular echodensities (PVE) and cysts that are 2 mm in diameter or larger. PVE were graded as mild or as moderate to severe, and cyst size was classified by widest diameter as either large (greater than or equal to 3 mm) or small (less than 3 mm). All 127 surviving infants with PVE or cyst formation or both were followed until spastic forms of CP could be diagnosed or excluded during late infancy. All 26 of the infants in whom spastic CP developed had moderate or severe PVE in the area superior and lateral to the caudothalamic notch as noted on the parasagittal images of the neonatal neurosonograms. All these infants also developed cysts in the periventricular region within the area of the previously noted PVE. Mild or moderate to severe PVE were not associated with the development of spastic CP in 101 infants. Cysts developed in the area of PVE in the neurosonographic studies of 42 of these 101 infants. Mild PVE without cysts and moderate to severe PVE without cysts had negative predictive values for CP of 69% and 76%, respectively. By contrast, the presence of moderate to severe PVEs with large cyst formation had positive and negative predictive values of 90% and 93%, respectively, and was the most sensitive and specific neurosonographic finding for predicting CP, with an efficiency of 92%. The presence or absence of intracranial hemorrhage did not increase the efficiency of the ultrasound test results.

Neurologic sequelae and MRI in low-birth weight patients

Periventricular hyperintensity was detected using long repetition and echo time on spin-echo magnetic resonance imaging in 24 of 32 children with birth weights less than 2,500 gm. Functionally, 11 children were normal, 6 mildly handicapped, 7 moderately handicapped, and 8 severely handicapped. The functional handicaps were correlated to the degree of periventricular hyperintensity observed on magnetic resonance imaging when periventricular hyperintensity was divided into 4 grades; therefore, the extent of periventricular hyperintensity observed on magnetic resonance imaging has been proved to be of value in the clinical assessment of low-birth weight infants and children and may contribute to the prediction of later functional deficits.

Intraventricular hemorrhage

A review of the role of ultrasound imaging in the diagnosis and study of intraventricular hemorrhage is presented. The characteristics of both early and late scans of germinal matrix, intraventricular, and intraparenchymal hemorrhage, as well as periventricular leukomalacia, have been worked out over the past decade. There is good agreement between the images and pathologic findings. A system of classification that recognizes the importance of parenchymal lesions and their evolution is suggested. The ability to perform repeated ultrasound examinations of sick premature infants has allowed the gathering of important information about pathophysiology, natural history, and outcome. In turn, these studies allow better interpretation of ultrasound scans in the individual infant. Using sequential scans when parenchymal lesions are found improves prognostic information. Prevention of intraventricular hemorrhage is still a goal. However, judging from the experience at our institution it may be that the subtle application of principles demonstrated by the study of this problem with ultrasound imaging has already begun to prevent intraventricular hemorrhage in some patients.

Etiologic heterogeneity of intracranial hemorrhages in preterm newborns

Hemorrhages in brain parenchyma and ventricles in preterm infants tend to be grouped as one entity. To help determine whether these hemorrhages should be viewed as one or more entities, we compared the risk profiles of 3 groups of hemorrhages defined by location and time of occurrence: early germinal matrix hemorrhage (GMH), late GMH, and late peri/intraventricular hemorrhage excluding GMH. These 3 groups were determined to have sufficient differences in various risk factors to warrant separate epidemiologic study.

Precision of ultrasound diagnosis of pathologically verified lesions in the brains of very preterm infants

Abnormalities detected by a mechanical sector scanner were compared 'blind' with autopsy findings in the brains of 56 infants born at less than 33 weeks gestation. Intraventricular haemorrhage was found in 53 of 112 hemispheres and had been accurately diagnosed by ultrasound (sensitivity 91 per cent; specificity 81 per cent). Isolated germinal layer haemorrhage was less successfully identified (sensitivity 61 per cent; specificity 78 per cent); false-positive diagnoses were partly due to difficulty in distinguishing haemorrhage from the normal choroid plexus in extremely preterm infants. Haemorrhagic parenchymal lesions were correctly identified in nine infants (sensitivity 82 per cent; specificity 97 per cent). Only 11 of 39 hemispheres with histological evidence of hypoxic-ischaemic injury, without marked bleeding, were correctly identified by ultrasound (sensitivity 28 per cent), mainly because of failure to detect small areas of periventricular leucomalacia and diffuse gliosis. 10 hemispheres with periventricular echodensities thought to represent leucomalacia showed no histological evidence of hypoxic-ischaemic injury (specificity 86 per cent). Ventricular dilatation in seven infants was always associated with evidence of hypoxic-ischaemic injury at autopsy.

Antenatal origin of neurologic damage in newborn infants. I. Preterm infants

Currently, the diagnosis of white matter necrosis may be performed with echoencephalography when cysts are observed in the white matter adjacent to the lateral ventricles. One hundred twenty-seven infants with a gestational age less than 36 weeks (mean [+/- SE] gestational age = 31 +/- 3.2 weeks) were studied in the neonatal period with echoencephalography to determine the incidence of white matter necrosis and the perinatal variables associated with this complication. Twenty-three infants (18.3%) had white matter necrosis. Thirteen (10.3%) had cysts by day 3 (11 on day 1), indicating that the onset of white matter necrosis occurred antenatally. The incidence of antenatal white matter necrosis was inversely related to birth weight and was more frequent in infants weighing less than 1000 gm (19%). Stepwise logistic regression analysis of 31 antenatal variables showed that placental vascular anastomoses in multiple pregnancies, funisitis, and purulent amniotic fluid were the only complications associated with antenatal white matter necrosis. Follow-up neurologic evaluations were abnormal in four of six patients with antenatal white matter necrosis. The findings in this study focus attention on prenatal, rather than intrapartum and postnatal, factors as causative agents of neurologic morbidity and emphasize the importance of early and sequential evaluation of neonatal brain structures.

Effect of timing of cerebral ultrasonography on the prediction of later neurodevelopmental outcome in high-risk preterm infants

To determine the predictive value of cranial ultrasonographic examination in high-risk preterm infants at different postnatal ages, we scanned 110 infants less than or equal to 32 weeks gestational age at 1, 2, 3, and 6 weeks postnatal ages and at 40 weeks postconceptional age (PCA). Cranial abnormalities detected by ultrasonography at each postnatal age of examination were classified as minor (periventricular superolateral echogenicity with or without intraventricular hemorrhage, grades 1 to 3) or major (cystic periventricular leukomalacia with or without intraventricular hemorrhage, grade 4) and correlated with neurodevelopmental outcome determined by 1 year of age. Major abnormalities detected by ultrasonography were present in four infants at 1 week, four at 2 weeks, eight at 3 weeks, and 11 infants at 6 weeks and 40 weeks PCA, respectively. Nineteen infants (17%) had moderate to severe functional handicaps defined as cerebral palsy, cognitive or visual deficit, or deafness. The positive and negative predictive values of ultrasound examinations, with regard to later neurodevelopmental outcome, improved with increasing postnatal age at examination and was best at 40 weeks PCA. Negative results of ultrasound study at 40 weeks PCA most correctly predicted satisfactory outcome. Although only 58% of moderately to severely handicapped infants were correctly identified by ultrasound examination at 40 weeks PCA, all infants with major ultrasonographic abnormalities at 40 weeks PCA had moderate or severe handicap. Our data demonstrate that the timing of cerebral ultrasonography is important in the prediction of later neurodevelopmental outcome in high-risk preterm infants.

Hemiplegic cerebral palsy. Aetiology and outcome

Hemiplegic cerebral palsy (CP) was studied in a retrospective population-based series of 169 cases from the South-western Swedish health care region covering the birth years 1969-78. The purpose was to analyse the prevalence, aetiology and neuro-developmental outcome in children born preterm and at term, and to correlate pathogenetic periods, aetiological factors and clinical parameters to neuroradiology. The prevalence at the ages 6-15 years was 0.66 per 1000. Postnatally acquired hemiplegia, mainly postinfectious, iatrogenic or posttraumatic, constituted 11%. Among term children with congenital hemiplegia (pre and perinatally derived) the aetiology was considered prenatal, mainly circulatory brain lesions and maldevelopments, in 42%, combined pre and perinatal in 9%, perinatal (cerebral haemorrhage, hypoxia) in 16% and untraceable in 34%. The corresponding distribution among preterm children was 29%, 47%, 25% and 6%, respectively. The rate of preterm birth among congenital cases was 24%. Birth asphyxia was shown to be a poor indicator of pathogenetic period, whereas a cascade of postpartum complications suggested perinatal brain damage. Clinical follow-up of 152 children revealed that 50% had mild, 31% moderate and 19% severe motor dysfunction. Stereognostic sense was impaired in 44% of the children (astereognosia in 20%). Additional impairments (mental retardation, epilepsy, impaired vision, hearing and speech, severe behavioural/perceptual problems) were present in 42%. Term children with congenital hemiplegia tended to be more severely affected than preterm children. The resulting total handicap was considered mild in 40%, moderate in 44% and severe in 16%. The prevalence of severe total handicap was highest among postnatal cases. Computerised tomography (CT), performed in 109 congenital cases, was normal in 26%, showed unilateral ventricular enlargement in 36% and revealed cortical/subcortical cavities in 20%. In the remaining 18% CT findings were classified as "other". With the classification so far used, correlations between CT findings and aetiologies were unsatisfactory and disappointing. In contrast, CT findings showed a strong correlation with clinical degree of severity and magnitude of associated handicap. As a rule, normal CT implied mild disability and unilateral ventricular enlargement moderate, whereas cortical/subcortical cavities were frequently associated with severe handicap, including mental retardation and epilepsy.

The evolution and outcome of cavitating periventricular leukomalacia in infancy. A study of 46 cases

Forty six infants with the ultrasonic diagnosis of cavitating periventricular leukomalacia (CPVL) have been reviewed. Follow up examination results allow correlation between the ultrasound appearances and subsequent neurodevelopmental and neurological deficits. The highest incidence of this condition was found in infants at and below 27 weeks gestation, and occurred in 15% of very premature infants surviving 14 days or more. Cavities developed 15 days after the onset of periventricular echodensity (median time). Ventricular dilatation occurred in 24% of the infants who developed cavities. Follow up information was available in 27 infants and 18 of these (67%) had significant neurodevelopmental handicap. The location of echolucent cavities were described as involving anterior, middle or posterior cerebral zones or any combination of these. Cerebral palsy was closely related to the presence of cavities, but there was little association between cavities and developmental delay. Four factors were found to predict cerebral palsy: cavities within the occipital zone, the involvement of multiple regions of the brain, lesions greater than 1 cm in diameter and cavities associated with subcortical leukomalacia. Lesions confined to the anterior or middle zones were unlikely to be associated with significant handicap. The presence of cavities per se was not associated with a higher incidence of severe developmental delay.

Interobserver variability in neonatal cranial ultrasonography

The reliability of cranial ultrasound diagnosis in the premature neonate was examined using data from an ongoing multicentre study of the epidemiology and long-term consequences of neonatal brain haemorrhage. First week ultrasound films (obtained at 4 hours, 24 hours and 7 days) from 60 study subjects were randomly selected for independent review by two groups of experienced interpreters, and results were recorded separately for observations (i.e. presence or absence of an abnormal echodense area on a film) and interpretations (i.e. presence or absence of haemorrhage or ventricular dilatation) in each hemisphere. Because of deaths in the first week of life, the total number of films examined was 138. Concordance on the presence or absence of an abnormal echodensity was examined for each individual film for three areas of interest: the germinal matrix, the ventricles and the parenchyma. Concordance on the presence or absence of haemorrhage or ventricular dilatation was examined only for the seventh-day film, or the final film prior to death. Finally, concordance was analysed with the diagnostic interpretations grouped into categories thought to differ prognostically for long-term outcome. In general, concordance was poorest for germinal matrix lesions and best for parenchymal lesions. Concordance was lower for observations made on each individual film than it was for interpretation of the final film in each case. Fifty-five of 60 cases (92%) were assigned to the same major prognostic category by both readers. Ultrasound review conferences were held periodically and there was evidence that concordance in ultrasound reading and interpretation improved during the course of the study.

Probability of neurodevelopmental disorders estimated from ultrasound appearance of brains of very preterm infants

The neurodevelopmental status of 342 very preterm infants who had undergone prospective ultrasound brainscans was assessed at a median corrected age of 52 weeks. The probabilities for neurodevelopmental disorders were calculated according to the ultrasound findings. The results showed that the probability of a major or minor disorder was low for infants whose scans did not show periventricular haemorrhage or markedly increased parenchymal echodensities in the first week of life, and for those whose scans at discharge gave no evidence of ventricular dilatation, hydrocephalus or cerebral atrophy. By contrast, the probability of a disorder was very high for infants with markedly increased parenchymal echodensities in the first week, and for infants with evidence of cerebral atrophy at discharge. The majority of the infants could be assigned, on the basis of the ultrasound scan at discharge, either to a large group who were at low risk of neurodevelopmental disorders or to a small group who were at high risk; the remainder were at intermediate risk. These findings may be used as a guide to the prognosis for other infants whose ultrasound scans show similar appearances.

Reliability of sonography in non-hemorrhagic periventricular leucomalacia

Sonographic pictures of the brain of 19 newborn infants who died at a mean age of 4.2 days after birth (range 1-23 days) were examined independently by five experienced sonographers. In all infants information on postmortem brain pathology was available. Diagnoses made by the sonographers based on the sonographic pictures were compared with the gross postmortem findings. The results of the study show that except for one infant with a subarachnoid hemorrhage all cerebral hemorrhages were diagnosed accurately by all sonographers. Non-hemorrhagic periventricular leucomalacia (PVL), however, was missed on sonography in 2 of the 3 cases. Surprisingly, PVL was diagnosed on sonography in 1 (8%) to 6 (50%) of 12 infants in which postmortem examination of the brain revealed no PVL. It is concluded that non-hemorrhagic PVL cannot be diagnosed accurately using sonography in the first days of life, if a 5 MHz transducer is used.